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Sample records for autocrine mechanism involving

  1. Vasoreparative dysfunction of CD34+ cells in diabetic individuals involves hypoxic desensitization and impaired autocrine/paracrine mechanisms.

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    Yagna P R Jarajapu

    Full Text Available We hypothesized that endothelial progenitor cells derived from individuals with diabetes would exhibit functional defects including inability to respond to hypoxia and altered paracrine/autocrine function that would impair the angiogenic potential of these cells. Circulating mononuclear cells isolated from diabetic (n = 69 and nondiabetic (n = 46 individuals were used to grow endothelial colony forming cells (ECFC, early endothelial progenitor cells (eEPCs and isolate CD34+ cells. ECFCs and eEPCs were established from only 15% of the diabetic individuals tested thus directing our main effort toward examination of CD34+ cells. CD34+ cells were plated in basal medium to obtain cell-free conditioned medium (CM. In CM derived from CD34+ cells of diabetic individuals (diabetic-CM, the levels of stem cell factor, hepatocyte growth factor, and thrombopoietin were lower, and IL-1β and tumor necrosis factor (TNFα levels were higher than CM derived from nondiabetic individuals (nondiabetic-CM. Hypoxia did not upregulate HIF1α in CD34+ cells of diabetic origin. Migration and proliferation of nondiabetic CD34+ cells toward diabetic-CM were lower compared to nondiabetic-CM. Attenuation of pressure-induced constriction, potentiation of bradykinin relaxation, and generation of cGMP and cAMP in arterioles were observed with nondiabetic-CM, but not with diabetic-CM. Diabetic-CM failed to induce endothelial tube formation from vascular tissue. These results suggest that diabetic subjects with microvascular complications exhibit severely limited capacity to generate ex-vivo expanded endothelial progenitor populations and that the vasoreparative dysfunction observed in diabetic CD34+ cells is due to impaired autocrine/paracrine function and reduced sensitivity to hypoxia.

  2. Vasoreparative dysfunction of CD34+ cells in diabetic individuals involves hypoxic desensitization and impaired autocrine/paracrine mechanisms.

    Science.gov (United States)

    Jarajapu, Yagna P R; Hazra, Sugata; Segal, Mark; Li Calzi, Sergio; LiCalzi, Sergio; Jadhao, Chandra; Jhadao, Chandra; Qian, Kevin; Mitter, Sayak K; Raizada, Mohan K; Boulton, Michael E; Grant, Maria B

    2014-01-01

    We hypothesized that endothelial progenitor cells derived from individuals with diabetes would exhibit functional defects including inability to respond to hypoxia and altered paracrine/autocrine function that would impair the angiogenic potential of these cells. Circulating mononuclear cells isolated from diabetic (n = 69) and nondiabetic (n = 46) individuals were used to grow endothelial colony forming cells (ECFC), early endothelial progenitor cells (eEPCs) and isolate CD34+ cells. ECFCs and eEPCs were established from only 15% of the diabetic individuals tested thus directing our main effort toward examination of CD34+ cells. CD34+ cells were plated in basal medium to obtain cell-free conditioned medium (CM). In CM derived from CD34+ cells of diabetic individuals (diabetic-CM), the levels of stem cell factor, hepatocyte growth factor, and thrombopoietin were lower, and IL-1β and tumor necrosis factor (TNFα) levels were higher than CM derived from nondiabetic individuals (nondiabetic-CM). Hypoxia did not upregulate HIF1α in CD34+ cells of diabetic origin. Migration and proliferation of nondiabetic CD34+ cells toward diabetic-CM were lower compared to nondiabetic-CM. Attenuation of pressure-induced constriction, potentiation of bradykinin relaxation, and generation of cGMP and cAMP in arterioles were observed with nondiabetic-CM, but not with diabetic-CM. Diabetic-CM failed to induce endothelial tube formation from vascular tissue. These results suggest that diabetic subjects with microvascular complications exhibit severely limited capacity to generate ex-vivo expanded endothelial progenitor populations and that the vasoreparative dysfunction observed in diabetic CD34+ cells is due to impaired autocrine/paracrine function and reduced sensitivity to hypoxia.

  3. Autocrine and Paracrine Mechanisms Promoting Chemoresistance in Cholangiocarcinoma

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    Massimiliano Cadamuro

    2017-01-01

    Full Text Available Resistance to conventional chemotherapeutic agents, a typical feature of cholangiocarcinoma, prevents the efficacy of the therapeutic arsenal usually used to combat malignancy in humans. Mechanisms of chemoresistance by neoplastic cholangiocytes include evasion of drug-induced apoptosis mediated by autocrine and paracrine cues released in the tumor microenvironment. Here, recent evidence regarding molecular mechanisms of chemoresistance is reviewed, as well as associations between well-developed chemoresistance and activation of the cancer stem cell compartment. It is concluded that improved understanding of the complex interplay between apoptosis signaling and the promotion of cell survival represent potentially productive areas for active investigation, with the ultimate aim of encouraging future studies to unveil new, effective strategies able to overcome current limitations on treatment.

  4. Cyclic mechanical deformation stimulates human lung fibroblast proliferation and autocrine growth factor activity.

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    Bishop, J E; Mitchell, J J; Absher, P M; Baldor, L; Geller, H A; Woodcock-Mitchell, J; Hamblin, M J; Vacek, P; Low, R B

    1993-08-01

    Cellular hypertrophy and hyperplasia and increased extracellular matrix deposition are features of tissue hypertrophy resulting from increased work load. It is known, for example, that mechanical forces play a critical role in lung development, cardiovascular remodeling following pressure overload, and skeletal muscle growth. The mechanisms involved in these processes, however, remain unclear. Here we examined the effect of mechanical deformation on fibroblast function in vitro. IMR-90 human fetal lung fibroblasts grown on collagen-coated silastic membranes were subjected to cyclical mechanical deformation (10% increase in culture surface area; 1 Hz) for up to 5 days. Cell number was increased by 39% after 2 days of deformation (1.43 +/- .01 x 10(5) cells/membrane compared with control, 1.03 +/- 0.02 x 10(5) cells; mean +/- SEM; P < 0.02) increasing to 163% above control by 4 days (2.16 +/- 0.16 x 10(5) cells compared with 0.82 +/- 0.03 x 10(5) cells; P < 0.001). The medium from mechanically deformed cells was mitogenic for IMR-90 cells, with maximal activity in the medium from cells mechanically deformed for 2 days (stimulating cell replication by 35% compared with media control; P < 0.002). These data suggest that mechanical deformation stimulates human lung fibroblast replication and that this effect is mediated by the release of autocrine growth factors.

  5. Autocrine growth factors are involved in branching morphogenesis of mouse lung epithelium.

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    Okada, Kimiko; Noda, Masatsugu; Nogawa, Hiroyuki

    2013-01-01

    The current model for branching morphogenesis of mouse lung proposes that the epithelium bifurcates as cells pursue separate sources of fibroblast growth factor (FGF) 10, secreted from mesenchymal tissue through interactions with epithelial tissue. If so, it may be assumed that the lung epithelium will grow into a uniform, expanding ball (without branching) when uniformly exposed to a constant concentration of FGF10. To test this hypothesis, we cultured Matrigel-embedded lung epithelium explants in FGF10-supplemented medium while shaking the culture dishes. Shaking cultures with FGF10 resulted in inferior epithelial branching compared to control cultures at rest. However, this effect was unexpectedly accompanied by poor growth rather than by ball-like expansion. When using FGF1, epithelial cultures grew and branched similarly well under either culture condition. Thus, we hypothesized that FGF10 signaling must be mediated by autocrine FGFs, such as FGF1, which might easily diffuse through the culture medium in the shaking culture. Reverse transcription-polymerase chain reaction analyses showed that FGF9 as well as FGF1 were expressed in the epithelium in vivo and in FGF10-stimulated epithelium in vitro, and FGF9 induced epithelial branching at a much lower concentration than FGF10. These results suggest that FGF1 and FGF9 may mediate FGF10 signaling and induce branching in the lung epithelium via autocrine signaling.

  6. Interleukin 6 promotes endometrial cancer growth through an autocrine feedback loop involving ERK–NF-κB signaling pathway

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    Che, Qi; Liu, Bin-Ya; Wang, Fang-Yuan; He, Yin-Yan; Lu, Wen; Liao, Yun [Department of Obstetrics and Gynecology, Shanghai First People’s Hospital Affiliated to Shanghai Jiao Tong University, Shanghai (China); Gu, Wei, E-mail: krisgu70@163.com [Department of Obstetrics and Gynecology, International Peace Maternity and Child Health Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai (China); Wan, Xiao-Ping, E-mail: wanxp@sjtu.edu.cn [Department of Obstetrics and Gynecology, Shanghai First Maternity and Infant Hospital Affiliated to Tong Ji University, Shanghai (China)

    2014-03-28

    Highlights: • IL-6 could promote endometrial cancer cells proliferation. • IL-6 promotes its own production through an autocrine feedback loop. • ERK and NF-κB pathway inhibitors inhibit IL-6 production and tumor growth. • IL-6 secretion relies on the activation of ERK–NF-κB pathway axis. • An orthotopic nude endometrial carcinoma model confirms the effect of IL-6. - Abstract: Interleukin (IL)-6 as an inflammation factor, has been proved to promote cancer proliferation in several human cancers. However, its role in endometrial cancer has not been studied clearly. Previously, we demonstrated that IL-6 promoted endometrial cancer progression through local estrogen biosynthesis. In this study, we proved that IL-6 could directly stimulate endometrial cancer cells proliferation and an autocrine feedback loop increased its production even after the withdrawal of IL-6 from the medium. Next, we analyzed the mechanism underlying IL-6 production in the feedback loop and found that its production and IL-6-stimulated cell proliferation were effectively blocked by pharmacologic inhibitors of nuclear factor-kappa B (NF-κB) and extra-cellular signal-regulated kinase (ERK). Importantly, activation of ERK was upstream of the NF-κB pathways, revealing the hierarchy of this event. Finally, we used an orthotopic nude endometrial carcinoma model to confirm the effects of IL-6 on the tumor progression. Taken together, these data indicate that IL-6 promotes endometrial carcinoma growth through an expanded autocrine regulatory loop and implicate the ERK–NF-κB pathway as a critical mediator of IL-6 production, implying IL-6 to be an important therapeutic target in endometrial carcinoma.

  7. Laminins promote postsynaptic maturation by an autocrine mechanism at the neuromuscular junction

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    Nishimune, Hiroshi; Jarad, George; Moulson, Casey L.; Müller, Ulrich; Miner, Jeffrey H.; Valdez, Gregorio; Sanes, Joshua R

    2008-01-01

    A prominent feature of synaptic maturation at the neuromuscular junction (NMJ) is the topological transformation of the acetylcholine receptor (AChR)-rich postsynaptic membrane from an ovoid plaque into a complex array of branches. We show here that laminins play an autocrine role in promoting this transformation. Laminins containing the α4, α5, and β2 subunits are synthesized by muscle fibers and concentrated in the small portion of the basal lamina that passes through the synaptic cleft at ...

  8. Vascular endothelial growth factor regulates osteoblast survival – evidence for an autocrine feedback mechanism

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    Street John

    2009-06-01

    Full Text Available Abstract Background Apoptosis of osteoblasts and osteoclasts regulates bone homeostasis. Skeletal injury in humans results in 'angiogenic' responses primarily mediated by vascular endothelial growth factor(VEGF, a protein essential for bone repair in animal models. Osteoblasts release VEGF in response to a number of stimuli and express receptors for VEGF in a differentiation dependent manner. This study investigates the putative role of VEGF in regulating the lifespan of primary human osteoblasts(PHOB in vitro. Methods PHOB were examined for VEGF receptors. Cultures were supplemented with VEGF(0–50 ng/mL, a neutralising antibody to VEGF, mAB VEGF(0.3 ug/mL and Placental Growth Factor (PlGF, an Flt-1 receptor-specific VEGF ligand(0–100 ng/mL to examine their effects on mineralised nodule assay, alkaline phosphatase assay and apoptosis.. The role of the VEGF specific antiapoptotic gene target BCl2 in apoptosis was determined. Results PHOB expressed functional VEGF receptors. VEGF 10 and 25 ng/mL increased nodule formation 2.3- and 3.16-fold and alkaline phosphatase release 2.6 and 4.1-fold respectively while 0.3 ug/mL of mAB VEGF resulted in approx 40% reductions in both. PlGF 50 ng/mL had greater effects on alkaline phosphatase release (103% increase than on nodule formation (57% increase. 10 ng/mL of VEGF inhibited spontaneous and pathological apoptosis by 83.6% and 71% respectively, while PlGF had no significant effect. Pretreatment with mAB VEGF, in the absence of exogenous VEGF resulted in a significant increase in apoptosis (14 vs 3%. VEGF 10 ng/mL increased BCl2 expression 4 fold while mAB VEGF decreased it by over 50%. Conclusion VEGF is a potent regulator of osteoblast life-span in vitro. This autocrine feedback regulates survival of these cells, mediated via a non flt-1 receptor mechanism and expression of BCl2 antiapoptotic gene.

  9. Laminins promote postsynaptic maturation by an autocrine mechanism at the neuromuscular junction.

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    Nishimune, Hiroshi; Valdez, Gregorio; Jarad, George; Moulson, Casey L; Müller, Ulrich; Miner, Jeffrey H; Sanes, Joshua R

    2008-09-22

    A prominent feature of synaptic maturation at the neuromuscular junction (NMJ) is the topological transformation of the acetylcholine receptor (AChR)-rich postsynaptic membrane from an ovoid plaque into a complex array of branches. We show here that laminins play an autocrine role in promoting this transformation. Laminins containing the alpha4, alpha5, and beta2 subunits are synthesized by muscle fibers and concentrated in the small portion of the basal lamina that passes through the synaptic cleft at the NMJ. Topological maturation of AChR clusters was delayed in targeted mutant mice lacking laminin alpha5 and arrested in mutants lacking both alpha4 and alpha5. Analysis of chimeric laminins in vivo and of mutant myotubes cultured aneurally demonstrated that the laminins act directly on muscle cells to promote postsynaptic maturation. Immunohistochemical studies in vivo and in vitro along with analysis of targeted mutants provide evidence that laminin-dependent aggregation of dystroglycan in the postsynaptic membrane is a key step in synaptic maturation. Another synaptically concentrated laminin receptor, Bcam, is dispensable. Together with previous studies implicating laminins as organizers of presynaptic differentiation, these results show that laminins coordinate post- with presynaptic maturation.

  10. Luminal and basal-like breast cancer cells show increased migration induced by hypoxia, mediated by an autocrine mechanism

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    Zänker Kurt S

    2011-05-01

    Full Text Available Abstract Background Some breast cancer patients receiving anti-angiogenic treatment show increased metastases, possibly as a result of induced hypoxia. The effect of hypoxia on tumor cell migration was assessed in selected luminal, post-EMT and basal-like breast carcinoma cell lines. Methods Migration was assessed in luminal (MCF-7, post-EMT (MDA-MB-231, MDA-MB-435S, and basal-like (MDA-MB-468 human breast carcinoma cell lines under normal and oxygen-deprived conditions, using a collagen-based assay. Cell proliferation was determined, secreted cytokine and chemokine levels were measured using flow-cytometry and a bead-based immunoassay, and the hypoxic genes HIF-1α and CA IX were assessed using PCR. The functional effect of tumor-cell conditioned medium on the migration of neutrophil granulocytes (NG was tested. Results Hypoxia caused increased migratory activity but not proliferation in all tumor cell lines, involving the release and autocrine action of soluble mediators. Conditioned medium (CM from hypoxic cells induced migration in normoxic cells. Hypoxia changed the profile of released inflammatory mediators according to cell type. Interleukin-8 was produced only by post-EMT and basal-like cell lines, regardless of hypoxia. MCP-1 was produced by MDA-MB-435 and -468 cells, whereas IL-6 was present only in MDA-MB-231. IL-2, TNF-α, and NGF production was stimulated by hypoxia in MCF-7 cells. CM from normoxic and hypoxic MDA-MB-231 and MDA-MB-435S cells and hypoxic MCF-7 cells, but not MDA-MB-468, induced NG migration. Conclusions Hypoxia increases migration by the autocrine action of released signal substances in selected luminal and basal-like breast carcinoma cell lines which might explain why anti-angiogenic treatment can worsen clinical outcome in some patients.

  11. Arsenite evokes IL-6 secretion, autocrine regulation of STAT3 signaling, and miR-21 expression, processes involved in the EMT and malignant transformation of human bronchial epithelial cells

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    Luo, Fei; Xu, Yuan [Institute of Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University (China); The Key Laboratory of Modern Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University (China); Ling, Min [Jiangsu Center for Disease Control and Prevention, Nanjing 211166, Jiangsu (China); Zhao, Yue; Xu, Wenchao [Institute of Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University (China); The Key Laboratory of Modern Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University (China); Liang, Xiao [Mental Health Center of Xuhui-CDC, Shanghai 200232 (China); Jiang, Rongrong; Wang, Bairu [Institute of Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University (China); The Key Laboratory of Modern Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University (China); Bian, Qian [Jiangsu Center for Disease Control and Prevention, Nanjing 211166, Jiangsu (China); Liu, Qizhan, E-mail: drqzliu@hotmail.com [Institute of Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University (China); The Key Laboratory of Modern Toxicology, Ministry of Education, School of Public Health, Nanjing Medical University (China)

    2013-11-15

    Arsenite is an established human carcinogen, and arsenite-induced inflammation contributes to malignant transformation of cells, but the molecular mechanisms by which cancers are produced remain to be established. The present results showed that, evoked by arsenite, secretion of interleukin-6 (IL-6), a pro-inflammatory cytokine, led to the activation of STAT3, a transcription activator, and to increased levels of a microRNA, miR-21. Blocking IL-6 with anti-IL-6 antibody and inhibiting STAT3 activation reduced miR-21 expression. For human bronchial epithelial cells, cultured in the presence of anti-IL-6 antibody for 3 days, the arsenite-induced EMT and malignant transformation were reversed. Thus, IL-6, acting on STAT3 signaling, which up-regulates miR-21in an autocrine manner, contributes to the EMT induced by arsenite. These data define a link from inflammation to EMT in the arsenite-induced malignant transformation of HBE cells. This link, mediated through miRNAs, establishes a mechanism for arsenite-induced lung carcinogenesis. - Highlights: • Arsenite evokes IL-6 secretion. • IL-6 autocrine mediates STAT3 signaling and up-regulates miR-21expression. • Inflammation is involved in arsenite-induced EMT.

  12. Distinguishing autocrine and paracrine signals in hematopoietic stem cell culture using a biofunctional microcavity platform

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    Müller, Eike; Wang, Weijia; Qiao, Wenlian; Bornhäuser, Martin; Zandstra, Peter W.; Werner, Carsten; Pompe, Tilo

    2016-08-01

    Homeostasis of hematopoietic stem cells (HSC) in the mammalian bone marrow stem cell niche is regulated by signals of the local microenvironment. Besides juxtacrine, endocrine and metabolic cues, paracrine and autocrine signals are involved in controlling quiescence, proliferation and differentiation of HSC with strong implications on expansion and differentiation ex vivo as well as in vivo transplantation. Towards this aim, a cell culture analysis on a polymer microcavity carrier platform was combined with a partial least square analysis of a mechanistic model of cell proliferation. We could demonstrate the discrimination of specific autocrine and paracrine signals from soluble factors as stimulating and inhibitory effectors in hematopoietic stem and progenitor cell culture. From that we hypothesize autocrine signals to be predominantly involved in maintaining the quiescent state of HSC in single-cell niches and advocate our analysis platform as an unprecedented option for untangling convoluted signaling mechanisms in complex cell systems being it of juxtacrine, paracrine or autocrine origin.

  13. Regulation of spermatogenesis by paracrine/autocrine testicular factors

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    MahmoudHuleihel; EitanLunenfeld

    2004-01-01

    Spermatogenesis is a complex process regulated by endocrine and testicular paracrine/autocrine factors.Gonadotropins are involved in the regulation of several testicular paracrine factors, mainly of the IL-1 family and testicular hormones. Testicular cytokines and growth factors (such as IL-1, IL-6, TNF, IFN-T, LIF and SCF) were shown to affect both the germ cell proliferation and the Leydig and Sertoli cells functions and secretion. Cytokines and growth factors are produced by immune cells and in the interstitial and seminiferous tubular compartments by various testicular cells, including Sertoli, Leydig, peritubular cells, spermatogonia, differentiated spermatogonia and even spermatozoa. Corresponding cytokine and growth factor receptors were demonstrated on some of the testicular cells. These cytokines also control the secretion of the gonadotropins and testosterone in the testis. Under pathological conditions the levels of pro-inflammatory cytokines are increased and negatively affected spermatogenesis. Thus,the expression levels and the mechanisms involved in the regulation of testicular paracrine/autocrine factors should be considered in future therapeutic strategies for male infertility. (Asian J Androl 2004 Sep; 6: 259-268)

  14. Autocrine and/or paracrine insulin-like growth factor-I activity in skeletal muscle

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    Adams, Gregory R.

    2002-01-01

    Similar to bone, skeletal muscle responds and adapts to changes in loading state via mechanisms that appear to be intrinsic to the muscle. One of the mechanisms modulating skeletal muscle adaptation it thought to involve the autocrine and/or paracrine production of insulinlike growth factor-I. This brief review outlines components of the insulinlike growth factor-I system as it relates to skeletal muscle and provides the rationale for the theory that insulinlike growth factor-I is involved with muscle adaptation.

  15. Neurophysiological mechanisms involved in auditory perceptual organization

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    Aurélie Bidet-Caulet

    2009-09-01

    Full Text Available In our complex acoustic environment, we are confronted with a mixture of sounds produced by several simultaneous sources. However, we rarely perceive these sounds as incomprehensible noise. Our brain uses perceptual organization processes to independently follow the emission of each sound source over time. If the acoustic properties exploited in these processes are well-established, the neurophysiological mechanisms involved in auditory scene analysis have raised interest only recently. Here, we review the studies investigating these mechanisms using electrophysiological recordings from the cochlear nucleus to the auditory cortex, in animals and humans. Their findings reveal that basic mechanisms such as frequency selectivity, forward suppression and multi-second habituation shape the automatic brain responses to sounds in a way that can account for several important characteristics of perceptual organization of both simultaneous and successive sounds. One challenging question remains unresolved: how are the resulting activity patterns integrated to yield the corresponding conscious perceptsµ

  16. Major regulatory mechanisms involved in sperm motility.

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    Pereira, Rute; Sá, Rosália; Barros, Alberto; Sousa, Mário

    2017-01-01

    The genetic bases and molecular mechanisms involved in the assembly and function of the flagellum components as well as in the regulation of the flagellar movement are not fully understood, especially in humans. There are several causes for sperm immotility, of which some can be avoided and corrected, whereas other are related to genetic defects and deserve full investigation to give a diagnosis to patients. This review was performed after an extensive literature search on the online databases PubMed, ScienceDirect, and Web of Science. Here, we review the involvement of regulatory pathways responsible for sperm motility, indicating possible causes for sperm immotility. These included the calcium pathway, the cAMP-dependent protein kinase pathway, the importance of kinases and phosphatases, the function of reactive oxygen species, and how the regulation of cell volume and osmolarity are also fundamental components. We then discuss main gene defects associated with specific morphological abnormalities. Finally, we slightly discuss some preventive and treatments approaches to avoid development of conditions that are associated with unspecified sperm immotility. We believe that in the near future, with the development of more powerful techniques, the genetic causes of sperm immotility and the regulatory mechanisms of sperm motility will be better understand, thus enabling to perform a full diagnosis and uncover new therapies.

  17. Regulation of Dense-Core Granule Replenishment by Autocrine BMP Signalling in Drosophila Secondary Cells.

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    Redhai, Siamak; Hellberg, Josephine E E U; Wainwright, Mark; Perera, Sumeth W; Castellanos, Felix; Kroeger, Benjamin; Gandy, Carina; Leiblich, Aaron; Corrigan, Laura; Hilton, Thomas; Patel, Benjamin; Fan, Shih-Jung; Hamdy, Freddie; Goberdhan, Deborah C I; Wilson, Clive

    2016-10-01

    Regulated secretion by glands and neurons involves release of signalling molecules and enzymes selectively concentrated in dense-core granules (DCGs). Although we understand how many secretagogues stimulate DCG release, how DCG biogenesis is then accelerated to replenish the DCG pool remains poorly characterised. Here we demonstrate that each prostate-like secondary cell (SC) in the paired adult Drosophila melanogaster male accessory glands contains approximately ten large DCGs, which are loaded with the Bone Morphogenetic Protein (BMP) ligand Decapentaplegic (Dpp). These DCGs can be marked in living tissue by a glycophosphatidylinositol (GPI) lipid-anchored form of GFP. In virgin males, BMP signalling is sporadically activated by constitutive DCG secretion. Upon mating, approximately four DCGs are typically released immediately, increasing BMP signalling, primarily via an autocrine mechanism. Using inducible knockdown specifically in adult SCs, we show that secretion requires the Soluble NSF Attachment Protein, SNAP24. Furthermore, mating-dependent BMP signalling not only promotes cell growth, but is also necessary to accelerate biogenesis of new DCGs, restoring DCG number within 24 h. Our analysis therefore reveals an autocrine BMP-mediated feedback mechanism for matching DCG release to replenishment as secretion rates fluctuate, and might explain why in other disease-relevant systems, like pancreatic β-cells, BMP signalling is also implicated in the control of secretion.

  18. Autocrine/Paracrine Human Growth Hormone-stimulated MicroRNA 96-182-183 Cluster Promotes Epithelial-Mesenchymal Transition and Invasion in Breast Cancer.

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    Zhang, Weijie; Qian, Pengxu; Zhang, Xiao; Zhang, Min; Wang, Hong; Wu, Mingming; Kong, Xiangjun; Tan, Sheng; Ding, Keshuo; Perry, Jo K; Wu, Zhengsheng; Cao, Yuan; Lobie, Peter E; Zhu, Tao

    2015-05-29

    Human growth hormone (hGH) plays critical roles in pubertal mammary gland growth, development, and sexual maturation. Accumulated studies have reported that autocrine/paracrine hGH is an orthotopically expressed oncoprotein that promotes normal mammary epithelial cell oncogenic transformation. Autocrine/paracrine hGH has also been reported to promote mammary epithelial cell epithelial-mesenchymal transition (EMT) and invasion. However, the underlying mechanism remains largely obscure. MicroRNAs (miRNAs) are reported to be involved in regulation of multiple cellular functions of cancer. To determine whether autocrine/paracrine hGH promotes EMT and invasion through modulation of miRNA expression, we performed microarray profiling using MCF-7 cells stably expressing wild type or a translation-deficient hGH gene and identified miR-96-182-183 as an autocrine/paracrine hGH-regulated miRNA cluster. Forced expression of miR-96-182-183 conferred on epithelioid MCF-7 cells a mesenchymal phenotype and promoted invasive behavior in vitro and dissemination in vivo. Moreover, we observed that miR-96-182-183 promoted EMT and invasion by directly and simultaneously suppressing BRMS1L (breast cancer metastasis suppressor 1-like) gene expression. miR-96 and miR-182 also targeted GHR, providing a potential negative feedback loop in the hGH-GHR signaling pathway. We further demonstrated that autocrine/paracrine hGH stimulated miR-96-182-183 expression and facilitated EMT and invasion via STAT3 and STAT5 signaling. Consistent with elevated expression of autocrine/paracrine hGH in metastatic breast cancer tissue, miR-96-182-183 expression was also remarkably enhanced. Hence, we delineate the roles of the miRNA-96-182-183 cluster and elucidate a novel hGH-GHR-STAT3/STAT5-miR-96-182-183-BRMS1L-ZEB1/E47-EMT/invasion axis, which provides further understanding of the mechanism of autocrine/paracrine hGH-stimulated EMT and invasion in breast cancer.

  19. Extrinsic Mechanisms Involved in Age-Related Defective Bone Formation

    DEFF Research Database (Denmark)

    Trinquier, Anne Marie-Pierre Emilie; Kassem, Moustapha

    2011-01-01

    the mechanisms involved in the age-related defective bone formation. Evidence Acquisition: The mechanisms discussed in this review are based on a PubMed search and knowledge of the authors in the field. Evidence Synthesis: Available basic and clinical studies indicate that multiple mechanisms are involved...

  20. Molecular mechanisms involved in intestinal iron absorption

    Institute of Scientific and Technical Information of China (English)

    Paul Sharp; Surjit Kaila Srai

    2007-01-01

    Iron is an essential trace metal in the human diet due to its obligate role in a number of metabolic processes.In the diet, iron is present in a number of different forms, generally described as haem (from haemoglobin and myoglobin in animal tissue) and non-haem iron (including ferric oxides and salts, ferritin and lactoferrin).This review describes the molecular mechanisms that co-ordinate the absorption of iron from the diet and its release into the circulation. While many components of the iron transport pathway have been elucidated, a number of key issues still remain to be resolved. Future work in this area will provide a clearer picture regarding the transcellular flux of iron and its regulation by dietary and humoral factors.

  1. Factors involved in mechanical fatigue degradation of dental resin composites.

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    Lohbauer, U; Belli, R; Ferracane, J L

    2013-07-01

    The design of clinical trials allows for limited insights into the fatigue processes occurring in resin composites and the factors involved therein. In vitro studies, in contrast, can fundamentally narrow study interests to focus on particular degradation mechanisms and, to date, represent the major contributors to the state of knowledge on the subject. These studies show that microstructural features are important in determining strength and fracture toughness, whereas fatigue resistance is mainly related to the susceptibility of the matrix and the filler/matrix interface to mechanical and chemical degradation. In this review, we focus on fracture mechanisms occurring during fatigue, on the methods used to assess them, and on additional phenomena involved in the degradation of initial mechanical properties of resin composites.

  2. Autocrine Effects of Tumor-Derived Complement

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    Min Soon Cho

    2014-03-01

    Full Text Available We describe a role for the complement system in enhancing cancer growth. Cancer cells secrete complement proteins that stimulate tumor growth upon activation. Complement promotes tumor growth via a direct autocrine effect that is partially independent of tumor-infiltrating cytotoxic T cells. Activated C5aR and C3aR signal through the PI3K/AKT pathway in cancer cells, and silencing the PI3K or AKT gene in cancer cells eliminates the progrowth effects of C5aR and C3aR stimulation. In patients with ovarian or lung cancer, higher tumoral C3 or C5aR mRNA levels were associated with decreased overall survival. These data identify a role for tumor-derived complement proteins in promoting tumor growth, and they therefore have substantial clinical and therapeutic implications.

  3. Damage response involves mechanisms conserved across plants, animals and fungi.

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    Hernández-Oñate, M A; Herrera-Estrella, A

    2015-08-01

    All organisms are constantly exposed to adverse environmental conditions including mechanical damage, which may alter various physiological aspects of growth, development and reproduction. In plant and animal systems, the damage response mechanism has been widely studied. Both systems posses a conserved and sophisticated mechanism that in general is aimed at repairing and preventing future damage, and causes dramatic changes in their transcriptomes, proteomes, and metabolomes. These damage-induced changes are mediated by elaborate signaling networks, which include receptors/sensors, calcium (Ca(2+)) influx, ATP release, kinase cascades, reactive oxygen species (ROS), and oxylipin signaling pathways. In contrast, our current knowledge of how fungi respond to injury is limited, even though various reports indicate that mechanical damage triggers reproductive processes. In fungi, the damage response mechanism has been studied more in depth in Trichoderma atroviride. Interestingly, these studies indicate that the mechanical damage response involves ROS, Ca(2+), kinase cascades, and lipid signaling pathways. Here we compare the response to mechanical damage in plants, animals and fungi and provide evidence that they appear to share signaling molecules and pathways, suggesting evolutionary conservation across the three kingdoms.

  4. Mechanisms Involved in Exercise-Induced Cardioprotection: A Systematic Review

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    Juliana Pereira Borges

    2015-01-01

    Full Text Available Background: Acute myocardial infarction is the leading cause of morbidity and mortality worldwide. Furthermore, research has shown that exercise, in addition to reducing cardiovascular risk factors, can also protect the heart against injury due to ischemia and reperfusion through a direct effect on the myocardium. However, the specific mechanism involved in exerciseinduced cardiac preconditioning is still under debate. Objective: To perform a systematic review of the studies that have addressed the mechanisms by which aerobic exercise promotes direct cardioprotection against ischemia and reperfusion injury. Methods: A search was conducted using MEDLINE, Literatura Latino-Americana e do Caribe de Informação em Ciências da Saúde, and Scientific Electronic Library Online databases. Data were extracted in a standardized manner by two independent researchers, who were responsible for assessing the methodological quality of the studies. Results: The search retrieved 78 studies; after evaluating the abstracts, 30 studies were excluded. The manuscripts of the remaining 48 studies were completely read and, of these, 20 were excluded. Finally, 28 studies were included in this systematic review. Conclusion: On the basis of the selected studies, the following are potentially involved in the cardioprotective response to exercise: increased heat shock protein production, nitric oxide pathway involvement, increased cardiac antioxidant capacity, improvement in ATP-dependent potassium channel function, and opioid system activation. Despite all the previous investigations, further research is still necessary to obtain more consistent conclusions.

  5. [Ocular involvement in spondylarthritis--new mechanisms, new therapies].

    Science.gov (United States)

    Itulescu, T C M; Alexandrescu, Cristina; Voinea, Liliana-Mary

    2014-01-01

    Spondyloarthrites (SPA) represent a group of heterogenous rheumatic diseases (ankylosing spondylitis/SA, psoriatic arthritis/PsA, reactive arthritis/ReA, spondyloarthritis in bowel inflammatory diseases/BID, undifferentiated spondyloarthritis/undif SpA) with distinct clinical features and common genetic predisposition (HLA-B27). SpA may also affect other organs, ocular involvement, represented by uveitis and conjunctivitis, being one of the most important extraskeletal manifestations. Pathogenic mechanisms of ocular involment in SpA are not entirely known; nevertheless, the inflammatory process which characterizes the main rheumatic diseases seems to be responsible for this extraskeletal manifestation. SpA treatment targeted at clinical remission has a favourable effect not only on articular but also on ocular involvement. The discovery of new pathogenic mechanisms of both rheumatic and eye disease in SpA have contributed to identification of new pathogenic therapies. The interdisciplinary team work of rheumatologists and ophtalmologists have prove essential for the management of SpA patients with ocular manifestations.

  6. Quantum-Mechanical Calculations on Molecular Substructures Involved in Nanosystems

    Directory of Open Access Journals (Sweden)

    Beata Szefler

    2014-09-01

    Full Text Available In this review article, four ideas are discussed: (a aromaticity of fullerenes patched with flowers of 6-and 8-membered rings, optimized at the HF and DFT levels of theory, in terms of HOMA and NICS criteria; (b polybenzene networks, from construction to energetic and vibrational spectra computations; (c quantum-mechanical calculations on the repeat units of various P-type crystal networks and (d construction and stability evaluation, at DFTB level of theory, of some exotic allotropes of diamond D5, involved in hyper-graphenes. The overall conclusion was that several of the yet hypothetical molecular nanostructures herein described are serious candidates to the status of real molecules.

  7. Cellular and Humoral Mechanisms Involved in the Control of Tuberculosis

    Directory of Open Access Journals (Sweden)

    Joaquin Zuñiga

    2012-01-01

    Full Text Available Mycobacterium tuberculosis (Mtb infection is a major international public health problem. One-third of the world's population is thought to have latent tuberculosis, a condition where individuals are infected by the intracellular bacteria without active disease but are at risk for reactivation, if their immune system fails. Here, we discuss the role of nonspecific inflammatory responses mediated by cytokines and chemokines induced by interaction of innate receptors expressed in macrophages and dendritic cells (DCs. We also review current information regarding the importance of several cytokines including IL-17/IL-23 in the development of protective cellular and antibody-mediated protective responses against Mtb and their influence in containment of the infection. Finally, in this paper, emphasis is placed on the mechanisms of failure of Mtb control, including the immune dysregulation induced by the treatment with biological drugs in different autoimmune diseases. Further functional studies, focused on the mechanisms involved in the early host-Mtb interactions and the interplay between host innate and acquired immunity against Mtb, may be helpful to improve the understanding of protective responses in the lung and in the development of novel therapeutic and prophylactic tools in TB.

  8. Mechanisms involved in BACE upregulation associated to stress.

    Science.gov (United States)

    Martisova, Eva; Solas, Maite; Gerenu, Gorka; Milagro, Fermin I; Campion, Javier; Ramirez, Maria J

    2012-09-01

    The objective of the present work was to study a purported involvement of stress in amyloid pathology through the modulation of BACE expression. Early-life stressed rats (maternal separation, MS) showed significant increases in corticosterone levels, BACE expression and Aβ levels. The CpG7 site of the BACE promoter was significantly hypomethylated in MS, and corticosterone levels negatively correlated to the methylation status of CpG7. The activation of the stress-activated protein kinase JNK was also increased in MS rats. In SHSY-5Y neuroblastoma cells, corticosterone induced a rapid increase in BACE expression that was abolished by specific inhibiton of JNK activation or by spironolactone, a mineralocorticoid receptor antagonist, but not by mifepristone, a glucocorticoid receptor antagonist. Corticosterone was also able to increase pJNK expression and this effect was fully reverted by spironolactone. Mice chronically treated with corticosterone showed increased BACE and pJNK expression. These increases were reverted by treatment with spironolactone or with a JNK inhibitor. It is suggested that increased corticosterone levels associated to stress lead to increase BACE transcription both through epigenetic mechanisms and activation of JNK.

  9. Prolactin as an autocrine/paracrine factor in breast tissue.

    Science.gov (United States)

    Clevenger, C V; Plank, T L

    1997-01-01

    The neuroendocrine hormone prolactin (PRL) stimulates breast growth and differentiation during puberty, pregnancy, and lactation. Despite extensive and convincing data indicating that PRL significantly contributes to the pathogenesis and progression of rodent mammary carcinoma, parallel observations for human breast cancer have not been concordant. In particular, the therapeutic alteration of somatolactogenic hormone levels has not consistently altered the course of human breast cancer. Recent data, however, suggest that extra-pituitary tissues are capable of elaborating PRL; indeed, the observation of sustained serum levels of PRL in post-hypophysectomy patients supports this hypothesis. Proof of an autocrine/paracrine loop for PRL within normal and malignant human breast tissues requires that the following three criteria be met: (1) PRL must be synthesized and secreted within mammary tissues; (2) the receptor for PRL (PRLR) must be present within these tissues; and, (3) proliferative responses to autocrine/paracrine PRL must be demonstrated. These criteria have now been fulfilled in several laboratories. With the demonstration of a PRL autocrine/paracrine loop in mammary glands, the basis for the ineffective treatment of human breast cancer by prior endocrine-based anti-somatolactogenic therapies is evident. These findings provide the precedent for novel therapeutic strategies aimed at interrupting the stimulation of breast cancer growth by PRL at both endocrine and autocrine/paracrine levels.

  10. MECHANISMS INVOLVED IN MYCORRHIZAL WHEAT PROTECTION AGAINST POWDERY MILDEW.

    Science.gov (United States)

    Mustafa, G; Tisserant, B; Randoux, B; Fontaine, J; Sahraoui, A Lounes-Hadj; Reignault, Ph

    2014-01-01

    In France, the Ecophyto 2018 national action plan will set out to reduce the use of pesticides by 50% by 2018, if possible. To achieve this goal, the use of arbuscular mycorrhizal (AM) fungi could be a potential alternative method allowing the control of crop diseases. The inoculation by AM fungi has been demonstrated to protect plants against soil-borne pathogens, but little is known about their effectiveness against aerial pathogens, such as the biotrophic fungus Blumeria graminis f.sp. tritici (Bgt) causing wheat (Triticum aestivum) powdery mildew. In the present study, wheat plants were grown in pots, under controlled conditions. Using various phosphorus (P) concentrations, the effectiveness of three AM inocula (Rhizophagus irregularis (Ri), Funneliformis mosseae (Fm)) and Solrize, a mixture of Ri and Fm) in Orvantis wheat cultivar, were tested. After 42 days of culture, mycorrhizal (M) and non-mycorrhizal (NM) wheat plants were infected by Bgt. A satisfactory mycorrhizal rate was obtained with the phosphorus concentration P/5 (P corresponding to the dose used in wheat fields in = 62 mg/L). Our work shows, for the first time, (i) a protective effect of AM inoculation against wheat powdery mildew, reaching up to 73% with Fm inocula, and (ii) its ability to induce a systemic resistance in wheat. Thereafter, we investigated mechanisms involved in this protection. Control plants, M plants, infected plants by Bgt, and M-infected plants were compared at: (i) cytological level, our results revealed that papillae and whole-fluorescent cells presence was induced, conversely fungal haustorium formation in epidermal cells was reduced within M plants leaves (ii) enzymatic level-by assessing defense enzyme activities (lipoxygenase, peroxidase) known as defense markers were measured 24, 48, 72 and 96 hours after infection (hai). The importance of these activities in the defense pathways induced in wheat by AM fungi will be discussed.

  11. Autocrine HBEGF expression promotes breast cancer intravasation, metastasis and macrophage-independent invasion in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Z. N.; Sharma, V. P.; Beaty, B. T.; Roh-Johnson, M.; Peterson, E. A.; Van Rooijen, N.; Kenny, P. A.; Wiley, H. S.; Condeelis, J. S.; Segall, J. E.

    2014-10-13

    Increased expression of HBEGF in estrogen receptor-negative breast tumors is correlated with enhanced metastasis to distant organ sites and more rapid disease recurrence upon removal of the primary tumor. Our previous work has demonstrated a paracrine loop between breast cancer cells and macrophages in which the tumor cells are capable of stimulating macrophages through the secretion of colony-stimulating factor-1 while the tumor-associated macrophages (TAMs), in turn, aid in tumor cell invasion by secreting epidermal growth factor. To determine how the autocrine expression of epidermal growth factor receptor (EGFR) ligands by carcinoma cells would affect this paracrine loop mechanism, and in particular whether tumor cell invasion depends on spatial ligand gradients generated by TAMs, we generated cell lines with increased HBEGF expression. We found that autocrine HBEGF expression enhanced in vivo intravasation and metastasis and resulted in a novel phenomenon in which macrophages were no longer required for in vivo invasion of breast cancer cells. In vitro studies revealed that expression of HBEGF enhanced invadopodium formation, thus providing a mechanism for cell autonomous invasion. The increased invadopodium formation was directly dependent on EGFR signaling, as demonstrated by a rapid decrease in invadopodia upon inhibition of autocrine HBEGF/EGFR signaling as well as inhibition of signaling downstream of EGFR activation. HBEGF expression also resulted in enhanced invadopodium function via upregulation of matrix metalloprotease 2 (MMP2) and MMP9 expression levels. We conclude that high levels of HBEGF expression can short-circuit the tumor cell/macrophage paracrine invasion loop, resulting in enhanced tumor invasion that is independent of macrophage signaling.

  12. Collagen and Stretch Modulate Autocrine Secretion of Insulin-like Growth Factor-1 and Insulin-like Growth Factor Binding Proteins from Differentiated Skeletal Muscle Cells

    Science.gov (United States)

    Perrone, Carmen E.; Fenwick-Smith, Daniela; Vandenburgh, Herman H.

    1995-01-01

    Stretch-induced skeletal muscle growth may involve increased autocrine secretion of insulin-like growth factor-1 (IGF-1) since IGF-1 is a potent growth factor for skeletal muscle hypertrophy, and stretch elevates IGF-1 mRNA levels in vivo. In tissue cultures of differentiated avian pectoralis skeletal muscle cells, nanomolar concentrations of exogenous IGF-1 stimulated growth in mechanically stretched but not static cultures. These cultures released up to 100 pg of endogenously produced IGF-1/micro-g of protein/day, as well as three major IGF binding proteins of 31, 36, and 43 kilodaltons (kDa). IGF-1 was secreted from both myofibers and fibroblasts coexisting in the muscle cultures. Repetitive stretch/relaxation of the differentiated skeletal muscle cells stimulated the acute release of IGF-1 during the first 4 h after initiating mechanical activity, but caused no increase in the long-term secretion over 24-72 h of IGF-1, or its binding proteins. Varying the intensity and frequency of stretch had no effect on the long-term efflux of IGF-1. In contrast to stretch, embedding the differentiated muscle cells in a three-dimensional collagen (Type I) matrix resulted in a 2-5-fold increase in long-term IGF-1 efflux over 24-72 h. Collagen also caused a 2-5-fold increase in the release of the IGF binding proteins. Thus, both the extracellular matrix protein type I collagen and stretch stimulate the autocrine secretion of IGF-1, but with different time kinetics. This endogenously produced growth factor may be important for the growth response of skeletal myofibers to both types of external stimuli.

  13. Homing orientation in salamanders: A mechanism involving chemical cues

    Science.gov (United States)

    Madison, D. M.

    1972-01-01

    A detailed description is given of experiments made to determine the senses and chemical cues used by salamanders for homing orientation. Sensory impairment and cue manipulative techniques were used in the investigation. All experiments were carried out at night. Results show that sense impaired animals did not home as readily as those who were blind but retained their sensory mechanism. This fact suggests that the olfactory mechanism is necessary for homing in the salamander. It was determined that after the impaired salamander regenerated its sensory mechanism it too returned home. It was concluded that homing ability in salamanders is direction independent, distant dependent, and vision independent.

  14. Molecular mechanisms involved in Weibel-Palade body exocytosis

    NARCIS (Netherlands)

    van Hooren, K.W.E.M.

    2014-01-01

    Endothelial cells form the barrier between the circulating blood and the underlying tissue. Endothelial cells contain specialized organelles called Weibel-Palade bodies that contain proteins involved in blood coagulation and inflammatory processes. In this thesis we describe a studies unraveling the

  15. Probing Embryonic Stem Cell Autocrine and Paracrine Signaling Using Microfluidics

    Science.gov (United States)

    Przybyla, Laralynne; Voldman, Joel

    2012-07-01

    Although stem cell fate is traditionally manipulated by exogenously altering the cells' extracellular signaling environment, the endogenous autocrine and paracrine signals produced by the cells also contribute to their two essential processes: self-renewal and differentiation. Autocrine and/or paracrine signals are fundamental to both embryonic stem cell self-renewal and early embryonic development, but the nature and contributions of these signals are often difficult to fully define using conventional methods. Microfluidic techniques have been used to explore the effects of cell-secreted signals by controlling cell organization or by providing precise control over the spatial and temporal cellular microenvironment. Here we review how such techniques have begun to be adapted for use with embryonic stem cells, and we illustrate how many remaining questions in embryonic stem cell biology could be addressed using microfluidic technologies.

  16. Mechanisms Involved in Nematode Control by Endophytic Fungi

    NARCIS (Netherlands)

    Schouten, Sander

    2016-01-01

    Colonization of plants by particular endophytic fungi can provide plants with improved defenses toward nematodes. Evidently, such endophytes can be important in developing more sustainable agricultural practices. The mechanisms playing a role in this quantitative antagonism are poorly understood

  17. General mechanism for helium blistering involving displaced atom transport

    Energy Technology Data Exchange (ETDEWEB)

    McDonell, W.R.

    1979-01-01

    A mechanism developed to account for formation of vertically elongated blisters in high displacement environments produced by /sup 252/Cf alpha particles and fission fragments has been extended to formation of done-shaped blisters in the low displacement environments produced by simple helium ion beams. In this mechanism, transport of displaced atoms to relieve compressive stresses in the helium-implanted layer allows interconnections of small, subsurface bubbles to form the blister cavity. The same transport may cause thickening of the blister caps at low implantation energies. The transition from dome-shaped to vertically elongated blistering occurs between the 300 and 3000 displacements per helium atom produced by simple helium ions and /sup 252/Cf radiations respectively.

  18. Autocrine glutamatergic transmission for the regulation of embryonal carcinoma stem cells.

    Science.gov (United States)

    Teng, Lin; Lei, Hui-Min; Sun, Fan; An, Shi-Min; Tang, Ya-Bin; Meng, Shuang; Wang, Cong-Hui; Shen, Ying; Chen, Hong-Zhuan; Zhu, Liang

    2016-08-02

    Glutamate behaves as the principal excitatory neurotransmitter in the vertebrate central nervous system and recently demonstrates intercellular signaling activities in periphery cancer cells. How the glutamatergic transmission is organized and operated in cancer stem cells remains undefined. We have identified a glutamatergic transmission circuit in embryonal carcinoma stem cells. The circuit is organized and operated in an autocrine mechanism and suppresses the cell proliferation and motility. Biological analyses determined a repertoire of glutamatergic transmission components, glutaminase, vesicular glutamate transporter, glutamate NMDA receptor, and cell membrane excitatory amino-acid transporter, for glutamate biosynthesis, package for secretion, reaction, and reuptake in mouse and human embryonal carcinoma stem cells. The glutamatergic components were also identified in mouse transplanted teratocarcinoma and in human primary teratocarcinoma tissues. Released glutamate acting as the signal was directly quantified by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Genetic and pharmacological abolishment of the endogenously released glutamate-induced tonic activation of the NMDA receptors increased the cell proliferation and motility. The finding suggests that embryonal carcinoma stem cells can be actively regulated by establishing a glutamatergic autocrine/paracrine niche via releasing and responding to the transmitter.

  19. Human neural stem cell-induced endothelial morphogenesis requires autocrine/paracrine and juxtacrine signaling

    Science.gov (United States)

    Chou, Chung-Hsing; Modo, Michel

    2016-01-01

    Transplanted neural stem cells (NSC) interact with the host brain microenvironment. A neovascularization is commonly observed in the vicinity of the cell deposit, which is correlated with behavioral improvements. To elucidate the signaling mechanisms between human NSCs and endothelial cells (ECs), these were cocultured in an in vitro model in which NSC-induced endothelial morphogenesis produced a neurovascular environment. Soluble (autocrine/paracrine) and contact–mediated (juxtacrine) signaling molecules were evaluated for two conditionally immortalized fetal NSC lines derived from the cortical anlage (CTXOE03) and ganglionic eminence (STROC05), as well as an adult EC line (D3) derived from the cerebral microvasculature of a hippocampal biopsy. STROC05 were 4 times as efficient to induce endothelial morphogenesis compared to CTXOE03. The cascade of reciprocal interactions between NSCs and ECs in this process was determined by quantifying soluble factors, receptor mapping, and immunocytochemistry for extracellular matrix molecules. The mechanistic significance of these was further evaluated by pharmacological blockade. The sequential cell-specific regulation of autocrine/paracrine and juxtacrine signaling accounted for the differential efficiency of NSCs to induce endothelial morphogenesis. These in vitro studies shed new light on the reciprocal interactions between NSCs and ECs, which are pivotal for our mechanistic understanding of the efficacy of NSC transplantation. PMID:27374240

  20. Molecular mechanisms involved in mammalian primary sex determination.

    Science.gov (United States)

    She, Zhen-Yu; Yang, Wan-Xi

    2014-08-01

    Sex determination refers to the developmental decision that directs the bipotential genital ridge to develop as a testis or an ovary. Genetic studies on mice and humans have led to crucial advances in understanding the molecular fundamentals of sex determination and the mutually antagonistic signaling pathway. In this review, we summarize the current molecular mechanisms of sex determination by focusing on the known critical sex determining genes and their related signaling pathways in mammalian vertebrates from mice to humans. We also discuss the underlying delicate balance between testis and ovary sex determination pathways, concentrating on the antagonisms between major sex determining genes.

  1. Chromosome catastrophes involve replication mechanisms generating complex genomic rearrangements.

    Science.gov (United States)

    Liu, Pengfei; Erez, Ayelet; Nagamani, Sandesh C Sreenath; Dhar, Shweta U; Kołodziejska, Katarzyna E; Dharmadhikari, Avinash V; Cooper, M Lance; Wiszniewska, Joanna; Zhang, Feng; Withers, Marjorie A; Bacino, Carlos A; Campos-Acevedo, Luis Daniel; Delgado, Mauricio R; Freedenberg, Debra; Garnica, Adolfo; Grebe, Theresa A; Hernández-Almaguer, Dolores; Immken, LaDonna; Lalani, Seema R; McLean, Scott D; Northrup, Hope; Scaglia, Fernando; Strathearn, Lane; Trapane, Pamela; Kang, Sung-Hae L; Patel, Ankita; Cheung, Sau Wai; Hastings, P J; Stankiewicz, Paweł; Lupski, James R; Bi, Weimin

    2011-09-16

    Complex genomic rearrangements (CGRs) consisting of two or more breakpoint junctions have been observed in genomic disorders. Recently, a chromosome catastrophe phenomenon termed chromothripsis, in which numerous genomic rearrangements are apparently acquired in one single catastrophic event, was described in multiple cancers. Here, we show that constitutionally acquired CGRs share similarities with cancer chromothripsis. In the 17 CGR cases investigated, we observed localization and multiple copy number changes including deletions, duplications, and/or triplications, as well as extensive translocations and inversions. Genomic rearrangements involved varied in size and complexities; in one case, array comparative genomic hybridization revealed 18 copy number changes. Breakpoint sequencing identified characteristic features, including small templated insertions at breakpoints and microhomology at breakpoint junctions, which have been attributed to replicative processes. The resemblance between CGR and chromothripsis suggests similar mechanistic underpinnings. Such chromosome catastrophic events appear to reflect basic DNA metabolism operative throughout an organism's life cycle.

  2. Kinetics and mechanisms of reactions involving small aromatic reactive intermediates

    Energy Technology Data Exchange (ETDEWEB)

    Lin, M.C. [Emory Univ., Atlanta, GA (United States)

    1993-12-01

    Small aromatic radicals such as C{sub 6}H{sub 5}, C{sub 6}H{sub 5}O and C{sub 6}H{sub 4} are key prototype species of their homologs. C{sub 6}H{sub 5} and its oxidation product, C{sub 6}H{sub 5}O are believed to be important intermediates which play a pivotal role in hydrocarbon combustion, particularly with regard to soot formation. Despite their fundamental importance, experimental data on the reaction mechanisms and reactivities of these species are very limited. For C{sub 6}H{sub 5}, most kinetic data except its reactions with NO and NO{sub 2}, were obtained by relative rate measurements. For C{sub 6}H{sub 5}O, the authors have earlier measured its fragmentation reaction producing C{sub 5}H{sub 5} + CO in shock waves. For C{sub 6}H{sub 4}, the only rate constant measured in the gas phase is its recombination rate at room temperature. The authors have proposed to investigate systematically the kinetics and mechanisms of this important class of molecules using two parallel laser diagnostic techniques--laser resonance absorption (LRA) and resonance enhanced multiphoton ionization mass spectrometry (REMPI/MS). In the past two years, study has been focused on the development of a new multipass adsorption technique--the {open_quotes}cavity-ring-down{close_quotes} technique for kinetic applications. The preliminary results of this study appear to be quite good and the sensitivity of the technique is at least comparable to that of the laser-induced fluorescence method.

  3. Mechanisms involved in alternariol-induced cell cycle arrest

    Energy Technology Data Exchange (ETDEWEB)

    Solhaug, A., E-mail: Anita.Solhaug@vetinst.no [Norwegian Veterinary Institute, Oslo (Norway); Vines, L.L. [Michigan State University, Department of Food Science and Human Nutrition, East Lansing, MI (United States); Ivanova, L.; Spilsberg, B. [Norwegian Veterinary Institute, Oslo (Norway); Holme, J.A. [Norwegian Institute of Public Health, Division of Environmental Medicine, Oslo (Norway); Pestka, J. [Michigan State University, Department of Food Science and Human Nutrition, East Lansing, MI (United States); Collins, A. [University of Oslo, Department of Nutrition, Faculty of Medicine, Oslo (Norway); Eriksen, G.S. [Norwegian Veterinary Institute, Oslo (Norway)

    2012-10-15

    Alternariol (AOH), a mycotoxin produced by Alternaria sp, is often found as a contaminant in fruit and cereal products. Here we employed the murine macrophage cell line RAW 264.7 to test the hypothesis that AOH causes toxicity as a response to DNA damage. AOH at concentrations of 15-30 {mu}M almost completely blocked cell proliferation. Within 30 min treatment, AOH (30 {mu}M) significantly increased the level of reactive oxygen species (ROS). Furthermore, DNA base oxidations as well as DNA strand breaks and/or alkaline labile sites were detected by the comet assay after 2 h exposure of AOH. Cell death (mostly necrosis) was observed after prolonged exposure to the highest concentration of AOH (60 {mu}M for 24 and 48 h) in our study. The DNA damage response involved phosphorylation (activation) of histone H2AX and check point kinase-1- and 2 (Chk-1/2). Moreover, AOH activated p53 and increased the expression of p21, Cyclin B, MDM2, and Sestrin 2; likewise the level of several miRNA was affected. AOH-induced Sestrin 2 expression was regulated by p53 and could at least partly be inhibited by antioxidants, suggesting a role of ROS in the response. Interestingly, the addition of antioxidants did not inhibit cell cycle arrest. Although the formation of ROS by itself was not directly linked cell proliferation, AOH-induced DNA damage and resulting transcriptional changes in p21, MDM2, and Cyclin B likely contribute to the reduced cell proliferation; while Sestrin 2 would contribute to the oxidant defense.

  4. Adipocytes promote prostate cancer stem cell self-renewal through amplification of the cholecystokinin autocrine loop.

    Science.gov (United States)

    Tang, Kai-Dun; Liu, Ji; Jovanovic, Lidija; An, Jiyuan; Hill, Michelle M; Vela, Ian; Lee, Terence Kin-Wah; Ma, Stephanie; Nelson, Colleen; Russell, Pamela J; Clements, Judith A; Ling, Ming-Tat

    2016-01-26

    Obesity has long been linked with prostate cancer progression, although the underlying mechanism is still largely unknown. Here, we report that adipocytes promote the enrichment of prostate cancer stem cells (CSCs) through a vicious cycle of autocrine amplification. In the presence of adipocytes, prostate cancer cells actively secrete the peptide hormone cholecystokinin (CCK), which not only stimulates prostate CSC self-renewal, but also induces cathepsin B (CTSB) production of the adipocytes. In return, CTSB facilitates further CCK secretion by the cancer cells. More importantly, inactivation of CCK receptor not only suppresses CTSB secretion by the adipocytes, but also synergizes the inhibitory effect of CTSB inhibitor on adipocyte-promoted prostate CSC self-renewal. In summary, we have uncovered a novel mechanism underlying the mutual interplay between adipocytes and prostate CSCs, which may help explaining the role of adipocytes in prostate cancer progression and provide opportunities for effective intervention.

  5. Mechanism involved in enhancement of osteoblast differentiation by hyaluronic acid

    Energy Technology Data Exchange (ETDEWEB)

    Kawano, Michinao [Division of Maxillofacial Diagnostic and Surgical Science, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Ariyoshi, Wataru [Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Iwanaga, Kenjiro [Division of Maxillofacial Diagnostic and Surgical Science, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Okinaga, Toshinori [Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Habu, Manabu [Division of Maxillofacial Diagnostic and Surgical Science, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Yoshioka, Izumi [Division of Oral and Maxillofacial Surgery, Department of Medicine of Sensory and Motor Organs, University of Miyazaki, Kiyotake, Miyazaki 889-1692 (Japan); Tominaga, Kazuhiro [Division of Maxillofacial Diagnostic and Surgical Science, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Oral Bioresearch Center, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Nishihara, Tatsuji, E-mail: tatsujin@kyu-dent.ac.jp [Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental College, Kitakyushu 803-8580 (Japan); Oral Bioresearch Center, Kyushu Dental College, Kitakyushu 803-8580 (Japan)

    2011-02-25

    Research highlights: {yields} In this study was to investigate the effects of HA on osteoblast differentiation induced by BMP-2. {yields} MG63 cells were incubated with BMP-2 and HA for various time periods. {yields} Phosphorylation of Smad 1/5/8, p38, and ERK proteins was determined by western blot analysis. To elucidate the nuclear translocation of phosphorylated Smad 1/5/8, stimulated cells were subjected to immunofluorescence microscopy. {yields} HA enhanced BMP-2 induces osteoblastic differentiation in MG63 cells via down-regulation of BMP-2 antagonists and ERK phosphorylation. -- Abstract: Objectives: Bone morphogenetic protein-2 (BMP-2) is expected to be utilized to fill bone defects and promote healing of fractures. However, it is unable to generate an adequate clinical response for use in bone regeneration. Recently, it was reported that glycosaminoglycans, including heparin, heparan sulfate, keratan sulfate, dermatan sulfate, chondroitin-4-sulfate, chondroitin-6-sulfate, and hyaluronic acid (HA), regulate BMP-2 activity, though the mechanism by which HA regulates osteogenic activities has not been fully elucidated. The aim of this study was to investigate the effects of HA on osteoblast differentiation induced by BMP-2. Materials and methods: Monolayer cultures of osteoblastic lineage MG63 cells were incubated with BMP-2 and HA for various time periods. To determine osteoblastic differentiation, alkaline phosphatase (ALP) activity in the cell lysates was quantified. Phosphorylation of Smad 1/5/8, p38, and ERK proteins was determined by Western blot analysis. To elucidate the nuclear translocation of phosphorylated Smad 1/5/8, stimulated cells were subjected to immunofluorescence microscopy. To further elucidate the role of HA in enhancement of BMP-2-induced Smad signaling, mRNA expressions of the BMP-2 receptor antagonists noggin and follistatin were detected using real-time RT-PCR. Results: BMP-2-induced ALP activation, Smad 1/5/8 phosphorylation, and

  6. Autocrine regulation of cell proliferation by estrogen receptor-alpha in estrogen receptor-alpha-positive breast cancer cell lines

    Directory of Open Access Journals (Sweden)

    Pan Zhongzong

    2009-01-01

    Full Text Available Abstract Background Estrogen receptor-α (ERα is essential for mammary gland development and is a major oncogene in breast cancer. Since ERα is not colocalized with the cell proliferation marker Ki-67 in the normal mammary glands and the majority of primary breast tumors, it is generally believed that paracrine regulation is involved in ERα mediated cell proliferation. In the paracrine model, ERα-positive cells don't proliferate but will release some paracrine growth factors to stimulate the neighboring cells to proliferate. In a subpopulation of cancer cells in some primary breast tumors, however, ERα does colocalize with the cell proliferation marker Ki-67, suggesting an autocrine regulation by ERα in some primary breast tumors. Methods Colocalization of ERα with Ki-67 in ERα-positive breast cancer cell lines (MCF-7, T47D, and ZR75-1 was evaluated by immunofluorescent staining. Cell cycle phase dependent expression of ERα was determined by co-immunofluorescent staining of ERα and the major cyclins (D, E, A, B, and by flow cytometry analysis of ERαhigh cells. To further confirm the autocrine action of ERα, MCF-7 cells were growth arrested by ICI182780 treatment, followed by treatment with EGFR inhibitor, before estrogen stimulation and analyses for colocalization of Ki-67 and ERα and cell cycle progression. Results Colocalization of ERα with Ki-67 was present in all three ERα-positive breast cancer cell lines. Unlike that in the normal mammary glands and the majority of primary breast tumors, ERα is highly expressed throughout the cell cycle in MCF-7 cells. Without E2 stimulation, MCF-7 cells released from ICI182780 treatment remain at G1 phase. E2 stimulation of ICI182780 treated cells, however, promotes the expression and colocalization of ERα and Ki-67 as well as the cell cycle progressing through the S and G2/M phases. Inhibition of EGFR signaling does not inhibit the autocrine action of ERα. Conclusion Our data indicate

  7. Interfollicular epidermal stem cells self-renew via autocrine Wnt signaling.

    Science.gov (United States)

    Lim, Xinhong; Tan, Si Hui; Koh, Winston Lian Chye; Chau, Rosanna Man Wah; Yan, Kelley S; Kuo, Calvin J; van Amerongen, Renée; Klein, Allon Moshe; Nusse, Roel

    2013-12-06

    The skin is a classical example of a tissue maintained by stem cells. However, the identity of the stem cells that maintain the interfollicular epidermis and the source of the signals that control their activity remain unclear. Using mouse lineage tracing and quantitative clonal analyses, we showed that the Wnt target gene Axin2 marks interfollicular epidermal stem cells. These Axin2-expressing cells constitute the majority of the basal epidermal layer, compete neutrally, and require Wnt/β-catenin signaling to proliferate. The same cells contribute robustly to wound healing, with no requirement for a quiescent stem cell subpopulation. By means of double-labeling RNA in situ hybridization in mice, we showed that the Axin2-expressing cells themselves produce Wnt signals as well as long-range secreted Wnt inhibitors, suggesting an autocrine mechanism of stem cell self-renewal.

  8. Adiponectin action: a combination of endocrine and autocrine/paracrine effects

    Directory of Open Access Journals (Sweden)

    Gary eSweeney

    2011-11-01

    Full Text Available The widespread physiological actions of adiponectin have now been well characterized as clinical studies and work in animal models have established strong correlations between circulating adiponectin levels and various disease-related outcomes. Thus, conventional thinking attributes many of adiponectins beneficial effects to endocrine actions of adipose-derived adiponectin. However, it is now clear that several tissues can themselves produce adiponectin and there is growing evidence that locally produced adiponectin can mediate functionally important autocrine or paracrine effects. In this review article we discuss regulation of adiponectin production, its mechanism of action via receptor isoforms and signaling pathways and its principal physiological effects (ie. metabolic and cardiovascular. The role of endocrine actions of adiponectin and changes in local production of adiponectin or its receptors in whole body physiology is discussed.

  9. Chemical Hypoxia Brings to Light Altered Autocrine Sphingosine-1-Phosphate Signalling in Rheumatoid Arthritis Synovial Fibroblasts

    Directory of Open Access Journals (Sweden)

    Chenqi Zhao

    2015-01-01

    Full Text Available Emerging evidence suggests a role for sphingosine-1-phosphate (S1P in various aspects of rheumatoid arthritis (RA pathogenesis. In this study we compared the effect of chemical hypoxia induced by cobalt chloride (CoCl2 on the expression of S1P metabolic enzymes and cytokine/chemokine secretion in normal fibroblast-like synoviocytes (FLS and RAFLS. RAFLS incubated with CoCl2, but not S1P, produced less IL-8 and MCP-1 than normal FLS. Furthermore, incubation with the S1P2 and S1P3 receptor antagonists, JTE-013 and CAY10444, reduced CoCl2-mediated chemokine production in normal FLS but not in RAFLS. RAFLS showed lower levels of intracellular S1P and enhanced mRNA expression of S1P phosphatase 1 (SGPP1 and S1P lyase (SPL, the enzymes that are involved in intracellular S1P degradation, when compared to normal FLS. Incubation with CoCl2 decreased SGPP1 mRNA and protein and SPL mRNA as well. Inhibition of SPL enhanced CoCl2-mediated cytokine/chemokine release and restored autocrine activation of S1P2 and S1P3 receptors in RAFLS. The results suggest that the sphingolipid pathway regulating the intracellular levels of S1P is dysregulated in RAFLS and has a significant impact on cell autocrine activation by S1P. Altered sphingolipid metabolism in FLS from patients with advanced RA raises the issue of synovial cell burnout due to chronic inflammation.

  10. SDF-1α is a novel autocrine activator of platelets operating through its receptor CXCR4.

    Science.gov (United States)

    Walsh, Tony G; Harper, Matthew T; Poole, Alastair W

    2015-01-01

    Platelets store and secrete the chemokine stromal cell-derived factor (SDF)-1α upon platelet activation, but the ability of platelet-derived SDF-1α to signal in an autocrine/paracrine manner mediating functional platelet responses relevant to thrombosis and haemostasis is unknown. We sought to explore the role of platelet-derived SDF-1α and its receptors, CXCR4 and CXCR7 in facilitating platelet activation and determine the mechanism facilitating SDF-1α-mediated regulation of platelet function. Using human washed platelets, CXCR4 inhibition, but not CXCR7 blockade significantly abrogated collagen-mediated platelet aggregation, dense granule secretion and thromboxane (Tx) A2 production. Time-dependent release of SDF-1α from collagen-activated platelets supports a functional role for SDF-1α in this regard. Using an in vitro whole blood perfusion assay, collagen-induced thrombus formation was substantially reduced with CXCR4 inhibition. In washed platelets, recombinant SDF-1α in the range of 20-100 ng/mL(-1) could significantly enhance platelet aggregation responses to a threshold concentration of collagen. These enhancements were completely dependent on CXCR4, but not CXCR7, which triggered TxA2 production and dense granule secretion. Rises in cAMP were significantly blunted by SDF-1α, which could also enhance collagen-mediated Ca2+ mobilisation, both of which were mediated by CXCR4. This potentiating effect of SDF-1α primarily required TxA2 signalling acting upstream of dense granule secretion, whereas blockade of ADP signalling could only partially attenuate SDF-1α-induced platelet activation. Therefore, this study supports a potentially novel autocrine/paracrine role for platelet-derived SDF-1α during thrombosis and haemostasis, through a predominantly TxA2-dependent and ADP-independent pathway.

  11. Mechanism(s) involved in opioid drug abuse modulation of HAND.

    Science.gov (United States)

    Dutta, Raini; Roy, Sabita

    2012-07-01

    Drug abuse and HIV infection are interlinked. From the onset of the HIV/AIDS epidemic, the impact of illicit drug use on HIV disease progression has been a focus of many investigations. Both laboratory-based and epidemiological studies strongly indicate that drug abuse may exacerbate HIV disease progression and increase mortality and morbidity in these patients. Increase susceptibility to opportunistic infection has been implicated as one of the major causes for this detriment. Furthermore, opioids are known to elicit prevalence of neurodegenerative disorders in HIV-infected patients. Numerous authors have delineated various molecular as well as cellular mechanisms associated with neurological complications in these patients. This review gives an overview of these findings. Understanding the mechanisms will allow for the development of targeted therapies aimed at reducing the progression of neurocognitive decline in the drug abusing HIV infected individuals.

  12. Mechanisms involved in regulation of osteoclastic differentiation by mechanical stress-loaded osteoblasts

    Energy Technology Data Exchange (ETDEWEB)

    Kaneuji, Takeshi [Division of Oral and Maxillofacial Reconstructive Surgery, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Ariyoshi, Wataru; Okinaga, Toshinori; Toshinaga, Akihiro [Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Takahashi, Tetsu [Division of Oral and Maxillofacial Reconstructive Surgery, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Oral Bioresearch Center, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Nishihara, Tatsuji, E-mail: tatsujin@kyu-dent.ac.jp [Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Oral Bioresearch Center, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan)

    2011-04-29

    Highlights: {yields} Effect of compressive force on osteoblasts were examined. {yields} Compressive force induced OPG expression and suppressed osteoclastogenesis. {yields} This enhancement of OPG is dependent on Wnt/Ca2+ signal pathway. -- Abstract: Mechanical stress is known to be important for regulation of bone turnover, though the detailed mechanisms are not fully understood. In the present study, we examined the effect of mechanical stress on osteoblasts using a novel compression model. Mouse osteoblastic MC3T3-E1 cells were embedded in three-dimensional (3D) gels and cultured with continuous compressive force (0-10.0 g/cm{sup 2}) for 48 h, and the conditioned medium were collected. RAW264.7 cells were then incubated with the conditioned medium for various times in the presence of receptor activator of nuclear factor-{kappa}B ligand (RANKL). Conditioned medium was found to inhibit the differentiation of RAW264.7 cells into osteoclasts induced by RANKL via down-regulation of the expression of tumor necrosis factor receptor-associated factor 6 (TRAF6), phosphorylation of I{kappa}B{alpha}, and nuclear translocation of p50 and p65. Interestingly, the conditioned medium also had a high level of binding activity to RANKL and blocked the binding of RANK to RANKL. Furthermore, the binding activity of conditioned medium to RANKL was reduced when the 3D gel was supplemented with KN-93, an inhibitor of non-canonical Wnt/Ca{sup 2+} pathway. In addition, expression level of osteoprotegerin (OPG) mRNA was increased in time- and force-dependent manners, and remarkably suppressed by KN-93. These results indicate that osteoblastic cells subjected to mechanical stress produce OPG, which binds to RANKL. Furthermore, this binding activity strongly inhibited osteoclastogenesis through suppression of TRAF6 and the nuclear factor-kappa B (NF-{kappa}B) signaling pathway, suggesting that enhancement of OPG expression induced by mechanical stress is dependent on non-canonical Wnt

  13. Autocrine Signaling and Quorum Sensing: Extreme Ends of a Common Spectrum.

    Science.gov (United States)

    Doğaner, Berkalp A; Yan, Lawrence K Q; Youk, Hyun

    2016-04-01

    'Secrete-and-sense cells' can communicate by secreting a signaling molecule while also producing a receptor that detects the molecule. The cell can potentially 'talk' to itself ('self-communication') or talk to neighboring cells with the same receptor ('neighbor communication'). The predominant forms of secrete-and-sense cells are self-communicating 'autocrine cells', which are largely found in animals, and neighbor-communicating 'quorum sensing cells', which are mostly associated with bacteria. While assumed to function independently of one another, recent studies have discovered quorum-sensing organs and autocrine-signaling microbes. Moreover, similar types of genetic circuit control many autocrine and quorum-sensing cells. Here, we outline these recent findings and explain how autocrine and quorum sensing are two sides of a many-sided 'dice' created by the versatile secrete-and-sense cell.

  14. BDNF, produced by a TPO-stimulated megakaryocytic cell line, regulates autocrine proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Shogo [Graduate School of Health Sciences, Hokkaido University, Sapporo (Japan); Research Fellow of the Japan Society for the Promotion of Science, Tokyo (Japan); Nagasawa, Ayumi; Masuda, Yuya; Tsunematsu, Tetsuya [Graduate School of Health Sciences, Hokkaido University, Sapporo (Japan); Hayasaka, Koji; Matsuno, Kazuhiko; Shimizu, Chikara [Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Sapporo (Japan); Ozaki, Yukio [Department of Clinical and Laboratory Medicine, Faculty of Medicine, University of Yamanashi (Japan); Moriyama, Takanori, E-mail: moriyama@hs.hokuda.ac.jp [Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Sapporo (Japan)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer It has been thought that BDNF is not produced in the megakaryocytic lineage. Black-Right-Pointing-Pointer MEG-01 produces BDNF upon TPO stimulation and regulates its proliferation. Black-Right-Pointing-Pointer BDNF accelerates proliferation of MEG-01 in an autocrine manner. Black-Right-Pointing-Pointer BDNF may be an autocrine MEG-CSF, which regulates megakaryopoiesis. -- Abstract: While human platelets release endogenous brain-derived neurotrophic factor (BDNF) upon activation, a previous report on MEG-01, a megakaryocytic cell line, found no trace of BDNF production, and the pathophysiological function of platelet BDNF has remained elusive. In the present study, we demonstrate that MEG-01 produces BDNF in the presence of TPO and that this serves to potentiate cell proliferation. Our in vitro findings suggest that BDNF regulates MEG-01 proliferation in an autocrine manner, and we suggest that BDNF may be a physiological autocrine regulator of megakaryocyte progenitors.

  15. FGF19 functions as autocrine growth factor for hepatoblastoma.

    Science.gov (United States)

    Elzi, David J; Song, Meihua; Blackman, Barron; Weintraub, Susan T; López-Terrada, Dolores; Chen, Yidong; Tomlinson, Gail E; Shiio, Yuzuru

    2016-03-01

    Hepatoblastoma is the most common liver cancer in children, accounting for over 65% of all childhood liver malignancies. Hepatoblastoma is distinct from adult liver cancer in that it is not associated with hepatitis virus infection, cirrhosis, or other underlying liver pathology. The paucity of appropriate cell and animal models has been hampering the mechanistic understanding of hepatoblastoma pathogenesis. Consequently, there is no molecularly targeted therapy for hepatoblastoma. To gain insight into cytokine signaling in hepatoblastoma, we employed mass spectrometry to analyze the proteins secreted from Hep293TT hepatoblastoma cell line we established and identified the specific secretion of fibroblast growth factor 19 (FGF19), a growth factor for liver cells. We determined that silencing FGF19 by shRNAs or neutralizing secreted FGF19 by anti-FGF19 antibody inhibits the proliferation of hepatoblastoma cells. Furthermore, blocking FGF19 signaling by an FGF receptor kinase inhibitor suppressed hepatoblastoma growth. RNA expression analysis in hepatoblastoma tumors revealed that the high expression of FGF19 signaling pathway components as well as the low expression of FGF19 signaling repression targets correlates with the aggressiveness of the tumors. These results suggest the role of FGF19 as autocrine growth factor for hepatoblastoma.

  16. Mechanisms involved in the transport of mercuric ions in target tissues.

    Science.gov (United States)

    Bridges, Christy C; Zalups, Rudolfs K

    2017-01-01

    Mercury exists in the environment in various forms, all of which pose a risk to human health. Despite guidelines regulating the industrial release of mercury into the environment, humans continue to be exposed regularly to various forms of this metal via inhalation or ingestion. Following exposure, mercuric ions are taken up by and accumulate in numerous organs, including brain, intestine, kidney, liver, and placenta. In order to understand the toxicological effects of exposure to mercury, a thorough understanding of the mechanisms that facilitate entry of mercuric ions into target cells must first be obtained. A number of mechanisms for the transport of mercuric ions into target cells and organs have been proposed in recent years. However, the ability of these mechanisms to transport mercuric ions and the regulatory features of these carriers have not been characterized completely. The purpose of this review is to summarize the current findings related to the mechanisms that may be involved in the transport of inorganic and organic forms of mercury in target tissues and organs. This review will describe mechanisms known to be involved in the transport of mercury and will also propose additional mechanisms that may potentially be involved in the transport of mercuric ions into target cells.

  17. GDNF protects enteric glia from apoptosis: evidence for an autocrine loop

    Directory of Open Access Journals (Sweden)

    Steinkamp Martin

    2012-01-01

    Full Text Available Abstract Background Enteric glia cells (EGC play an important role in the maintenance of intestinal mucosa integrity. During the course of acute Crohn's disease (CD, mucosal EGC progressively undergo apoptosis, though the mechanisms are largely unknown. We investigated the role of Glial-derived neurotrophic factor (GDNF in the regulation of EGC apoptosis. Methods GDNF expression and EGC apoptosis were determined by immunofluorescence using specimen from CD patients. In primary rat EGC cultures, GDNF receptors were assessed by western blot and indirect immunofluorescence microscopy. Apoptosis in cultured EGC was induced by TNF-α and IFN-γ, and the influence of GDNF on apoptosis was measured upon addition of GDNF or neutralizing anti-GDNF antibody. Results Increased GDNF expression and Caspase 3/7 activities were detected in in specimen of CD patients but not in healthy controls. Moreover, inactivation of GDNF sensitized in EGC cell to IFN-γ/TNF-α induced apoptosis. Conclusions This study proposes the existence of an autocrine anti-apoptotic loop in EGC cells which is operative in Crohn's disease and dependent of GDNF. Alterations in this novel EGC self-protecting mechanism could lead to a higher susceptibility towards apoptosis and thus contribute to disruption of the mucosal integrity and severity of inflammation in CD.

  18. A theoretical study of the molecular mechanism of the GAPDH Trypanosoma cruzi enzyme involving iodoacetate inhibitor

    Science.gov (United States)

    Carneiro, Agnaldo Silva; Lameira, Jerônimo; Alves, Cláudio Nahum

    2011-10-01

    The glyceraldehyde-3-phosphate dehydrogenase enzyme (GAPDH) is an important biological target for the development of new chemotherapeutic agents against Chagas disease. In this Letter, the inhibition mechanism of GAPDH involving iodoacetate (IAA) inhibitor was studied using the hybrid quantum mechanical/molecular mechanical (QM/MM) approach and molecular dynamic simulations. Analysis of the potential energy surface and potential of mean force show that the covalent attachment of IAA inhibitor to the active site of the enzyme occurs as a concerted process. In addition, the energy terms decomposition shows that NAD+ plays an important role in stabilization of the reagents and transition state.

  19. Fibroblast growth factor receptor 4 (FGFR4) and fibroblast growth factor 19 (FGF19) autocrine enhance breast cancer cells survival.

    Science.gov (United States)

    Tiong, Kai Hung; Tan, Boon Shing; Choo, Heng Lungh; Chung, Felicia Fei-Lei; Hii, Ling-Wei; Tan, Si Hoey; Khor, Nelson Tze Woei; Wong, Shew Fung; See, Sze-Jia; Tan, Yuen-Fen; Rosli, Rozita; Cheong, Soon-Keng; Leong, Chee-Onn

    2016-09-06

    Basal-like breast cancer is an aggressive tumor subtype with poor prognosis. The discovery of underlying mechanisms mediating tumor cell survival, and the development of novel agents to target these pathways, is a priority for patients with basal-like breast cancer. From a functional screen to identify key drivers of basal-like breast cancer cell growth, we identified fibroblast growth factor receptor 4 (FGFR4) as a potential mediator of cell survival. We found that FGFR4 mediates cancer cell survival predominantly via activation of PI3K/AKT. Importantly, a subset of basal-like breast cancer cells also secrete fibroblast growth factor 19 (FGF19), a canonical ligand specific for FGFR4. siRNA-mediated silencing of FGF19 or neutralization of extracellular FGF19 by anti-FGF19 antibody (1A6) decreases AKT phosphorylation, suppresses cancer cell growth and enhances doxorubicin sensitivity only in the FGFR4+/FGF19+ breast cancer cells. Consistently, FGFR4/FGF19 co-expression was also observed in 82 out of 287 (28.6%) primary breast tumors, and their expression is strongly associated with AKT phosphorylation, Ki-67 staining, higher tumor stage and basal-like phenotype. In summary, our results demonstrated the presence of an FGFR4/FGF19 autocrine signaling that mediates the survival of a subset of basal-like breast cancer cells and suggest that inactivation of this autocrine loop may potentially serve as a novel therapeutic intervention for future treatment of breast cancers.

  20. Mechanisms involved in calcium deficiency development in tomato fruit in response to gibberellins

    Science.gov (United States)

    Although gibberellins (GAs) have been shown to induce the calcium deficiency disorder, blossom-end rot (BER), development in tomato fruit (Solanum lycopersicum), the mechanisms involved remain largely unexplored. Our objectives were to better understand how GAs and a GA biosynthesis inhibitor affect...

  1. EFFECTS OF AMINO ACIDS ON THE MEMBRANE POTENTIAL OF TOAD OOCYTES AND THE MECHANISMS INVOLVED

    Institute of Scientific and Technical Information of China (English)

    WANGYu-Feng; CHENGJiun; CHENGZhi-Ping

    1989-01-01

    The etTects of 23 amino acids on the membrane potential of toad ( Bufo bufo gargarizans ) oocytes and the mechanisms involved were investigated in vitro by means of microelectrode. At a concentration of I mmol/L-alanine, leucine and lyaine induced signfiant depolarization, and tryptophan provoked a marked hyperpolarization during

  2. Involvement of the mechanoreceptors in the sensory mechanisms of manual and electrical acupuncture.

    Science.gov (United States)

    Yamamoto, Hiromi; Kawada, Toru; Kamiya, Atsunori; Miyazaki, Shunichi; Sugimachi, Masaru

    2011-02-24

    The modalities of acupuncture can be broadly classified into manual acupuncture (MA) and electroacupuncture (EA). Although MA has been reported to cause winding of tissue around the needle and subsequent activation of the sensory mechanoreceptors and nociceptors, the sensory mechanisms of acupuncture stimulation are not fully understood. To test the hypothesis that the involvement of the mechanoreceptors in the sensory mechanism is different in MA and EA, we examined the effects of a stretch-activated channel blocker gadolinium on the hemodynamic responses to hind limb MA and EA in anesthetized rats (n = 9). Gadolinium significantly attenuated the MA-induced bradycardic response (-22 ± 5 vs. -10 ± 3 bpm, Pmechanoreceptors are involved in the sensory mechanisms for both MA and EA.

  3. Positive Feedback Loop of Autocrine BDNF from Microglia Causes Prolonged Microglia Activation

    Directory of Open Access Journals (Sweden)

    Xin Zhang

    2014-08-01

    Full Text Available Background/Aims: Microglia, which represent the immune cells of the central nervous system (CNS, have long been a subject of study in CNS disease research. Substantial evidence indicates that microglial activation functions as a strong neuro-inflammatory response in neuropathic pain, promoting the release of pro-inflammatory cytokines, such as tumor necrosis factor (TNF-α. In addition, activated microglia release brain-derived neurotrophic factor (BDNF, which acts as a powerful cytokine. In this study, we performed a series of in vitro experiments to examine whether a positive autocrine feedback loop existed between microglia-derived BDNF and subsequent microglial activation as well as the mechanisms underlying this positive feedback loop. Methods: Because ATP is a classic inducer of microglial activation, firstly, we examined ATP-activated microglia in the present study. Secondly, we used TrkB/Fc, the BDNF sequester, to eliminate the effects of endogenous BDNF. ATP-stimulated microglia without BDNF was examined. Finally, we used exogenous BDNF to further determine whether BDNF could directly activate BV2 microglia. In all experiments, to quantify BV2 microglia activation, the protein levels of CD11b, a microglial activation marker, were measured by western blot. A Transwell migration assay was used to examine microglial migration. To assess the synthesis and release of proinflammatory cytokines, western blot was used to measure BDNF synthesis, and ELISA was used to quantify TNF-α release. Results: In our present research, we have observed that ATP dramatically activates microglia, enhancing microglial migration, increasing the synthesis of BDNF and up-regulating the release of TNF-α. Microglial activation is inhibited following the sequestration of endogenous BDNF, resulting in impaired microglial migration and decreased TNF-α release. Furthermore, exogenous BDNF can also activate microglia to subsequently enhance migration and increase TNF

  4. Seminal vesicle intraepithelial involvement by prostate cancer: putative mechanism and clinicopathological significance.

    Science.gov (United States)

    Miyai, Kosuke; Kristiansen, Anna; Egevad, Lars; Pina-Oviedo, Sergio; Divatia, Mukul K; Shen, Steven S; Miles, Brian J; Ayala, Alberto G; Park, Yong Wook; Ro, Jae Y

    2014-09-01

    We have recently shown seminal vesicle intraepithelial involvement of prostate cancer in cases with seminal vesicle invasion (pT3b). Based on the manner of seminal vesicle invasion, there could be 2 possible mechanisms of seminal vesicle intraepithelial involvement: direct intraepithelial invasion from prostate carcinoma in the muscular wall of seminal vesicles or intraepithelial involvement of cancer from the invaginated extraprostatic space (IES)/ejaculatory duct system to extraprostatic seminal vesicle. We aimed to clarify the manner and clinicopathological significance of seminal vesicle intraepithelial involvement. Of 1629 consecutive radical prostatectomies, 109 cases (6.7%) showed seminal vesicle invasion in whole-mounted radical prostatectomy specimens. In these pT3b cases, 18 (17%) showed seminal vesicle intraepithelial involvement by prostate cancer. Stromal invasion of the IES/ejaculatory duct system and ejaculatory duct intraepithelial invasion by prostate cancer were identified in 62 and 5 of 109 pT3b cases, respectively. However, the presence/absence of IES/ejaculatory duct system involvement by prostate cancer does not predict seminal vesicle intraepithelial involvement. No statistically significant correlation was observed between all pathologic parameters/biochemical recurrence and the presence/absence of seminal vesicle intra-epithelial involvement in the pT3b cases. These findings suggest that seminal vesicle intraepithelial involvement is more likely due to direct invasion of carcinoma from the muscular wall of seminal vesicles rather than intraepithelial extension from the ejaculatory duct system in the IES. Further studies with a substantially greater case number are needed to clarify the clinicopathological significance of seminal vesicle intraepithelial involvement in a better manner.

  5. Cell resistance to the Cytolethal Distending Toxin involves an association of DNA repair mechanisms

    Science.gov (United States)

    Bezine, Elisabeth; Malaisé, Yann; Loeuillet, Aurore; Chevalier, Marianne; Boutet-Robinet, Elisa; Salles, Bernard; Mirey, Gladys; Vignard, Julien

    2016-01-01

    The Cytolethal Distending Toxin (CDT), produced by many bacteria, has been associated with various diseases including cancer. CDT induces DNA double-strand breaks (DSBs), leading to cell death or mutagenesis if misrepaired. At low doses of CDT, other DNA lesions precede replication-dependent DSB formation, implying that non-DSB repair mechanisms may contribute to CDT cell resistance. To address this question, we developed a proliferation assay using human cell lines specifically depleted in each of the main DNA repair pathways. Here, we validate the involvement of the two major DSB repair mechanisms, Homologous Recombination and Non Homologous End Joining, in the management of CDT-induced lesions. We show that impairment of single-strand break repair (SSBR), but not nucleotide excision repair, sensitizes cells to CDT, and we explore the interplay of SSBR with the DSB repair mechanisms. Finally, we document the role of the replicative stress response and demonstrate the involvement of the Fanconi Anemia repair pathway in response to CDT. In conclusion, our work indicates that cellular survival to CDT-induced DNA damage involves different repair pathways, in particular SSBR. This reinforces a model where CDT-related genotoxicity primarily involves SSBs rather than DSBs, underlining the importance of cell proliferation during CDT intoxication and pathogenicity. PMID:27775089

  6. Cysteinyl leukotrienes are autocrine and paracrine regulators of fibrocyte function.

    Science.gov (United States)

    Vannella, Kevin M; McMillan, Tracy R; Charbeneau, Ryan P; Wilke, Carol A; Thomas, Peedikayil E; Toews, Galen B; Peters-Golden, Marc; Moore, Bethany B

    2007-12-01

    Pulmonary fibrosis is characterized by the accumulation of fibroblasts and myofibroblasts. These cells may accumulate from three potential sources: the expansion of resident lung fibroblasts, the process of epithelial-mesenchymal transition, or the recruitment and differentiation of circulating mesenchymal precursors known as fibrocytes. We have previously demonstrated that fibrocytes participate in lung fibrogenesis following administration of FITC to mice. We now demonstrate that leukotriene-deficient 5-LO(-/-) mice are protected from FITC-induced fibrosis. Both murine and human fibrocytes express both cysteinyl leukotriene receptor (CysLT) 1 and CysLT2. In addition, fibrocytes are capable of producing CysLTs and can be regulated via the autocrine or paracrine secretion of these lipid mediators. Exogenous administration of leukotriene (LT) D(4), but not LTC(4) induces proliferation of both murine and human fibrocytes in a dose-dependent manner. Consistent with this result, CysLT1 receptor antagonists are able to block the mitogenic effects of exogenous LTD(4) on fibrocytes. Endogenous production of CysLTs contributes to basal fibrocyte proliferation, but does not alter fibrocyte responses to basic fibroblast growth factor. Although CysLTs can induce the migration of fibrocytes in vitro, they do not appear to be essential for fibrocyte recruitment to the lung in vivo, possibly due to compensatory chemokine-mediated recruitment signals. However, CysLTs do appear to regulate the proliferation of fibrocytes once they are recruited to the lung. These data provide mechanistic insight into the therapeutic benefit of leukotriene synthesis inhibitors and CysLT1 receptor antagonists in animal models of fibrosis.

  7. Cissus sicyoides: Pharmacological Mechanisms Involved in the Anti-Inflammatory and Antidiarrheal Activities

    Science.gov (United States)

    Beserra, Fernando Pereira; de Cássia Santos, Raquel; Périco, Larissa Lucena; Rodrigues, Vinicius Peixoto; de Almeida Kiguti, Luiz Ricardo; Saldanha, Luiz Leonardo; Pupo, André Sampaio; da Rocha, Lúcia Regina Machado; Dokkedal, Anne Lígia; Vilegas, Wagner; Hiruma-Lima, Clélia Akiko

    2016-01-01

    The objective of this study was to evaluate the pharmacological mechanisms involved in anti-inflammatory and antidiarrheal actions of hydroalcoholic extract obtained from the leaves of Cissus sicyoides (HECS). The anti-inflammatory effect was evaluated by oral administration of HECS against acute model of edema induced by xylene, and the mechanisms of action were analysed by involvement of arachidonic acid (AA) and prostaglandin E2 (PGE2). The antidiarrheal effect of HECS was observed and we analyzed the motility and accumulation of intestinal fluid. We also analyzed the antidiarrheal mechanisms of action of HECS by evaluating the role of the opioid receptor, α2 adrenergic receptor, muscarinic receptor, nitric oxide (NO) and PGE2. The oral administration of HECS inhibited the edema induced by xylene and AA and was also able to significantly decrease the levels of PGE2. The extract also exhibited significant anti-diarrheal activity by reducing motility and intestinal fluid accumulation. This extract significantly reduced intestinal transit stimulated by muscarinic agonist and intestinal secretion induced by PGE2. Our data demonstrate that the mechanism of action involved in the anti-inflammatory effect of HECS is related to PGE2. The antidiarrheal effect of this extract may be mediated by inhibition of contraction by acting on the intestinal smooth muscle and/or intestinal transit. PMID:26805827

  8. Cissus sicyoides: Pharmacological Mechanisms Involved in the Anti-Inflammatory and Antidiarrheal Activities

    Directory of Open Access Journals (Sweden)

    Fernando Pereira Beserra

    2016-01-01

    Full Text Available The objective of this study was to evaluate the pharmacological mechanisms involved in anti-inflammatory and antidiarrheal actions of hydroalcoholic extract obtained from the leaves of Cissus sicyoides (HECS. The anti-inflammatory effect was evaluated by oral administration of HECS against acute model of edema induced by xylene, and the mechanisms of action were analysed by involvement of arachidonic acid (AA and prostaglandin E2 (PGE2. The antidiarrheal effect of HECS was observed and we analyzed the motility and accumulation of intestinal fluid. We also analyzed the antidiarrheal mechanisms of action of HECS by evaluating the role of the opioid receptor, α2 adrenergic receptor, muscarinic receptor, nitric oxide (NO and PGE2. The oral administration of HECS inhibited the edema induced by xylene and AA and was also able to significantly decrease the levels of PGE2. The extract also exhibited significant anti-diarrheal activity by reducing motility and intestinal fluid accumulation. This extract significantly reduced intestinal transit stimulated by muscarinic agonist and intestinal secretion induced by PGE2. Our data demonstrate that the mechanism of action involved in the anti-inflammatory effect of HECS is related to PGE2. The antidiarrheal effect of this extract may be mediated by inhibition of contraction by acting on the intestinal smooth muscle and/or intestinal transit.

  9. Tissue transglutaminase is involved in mechanical load-induced osteogenic differentiation of human ligamentum flavum cells.

    Science.gov (United States)

    Chao, Yuan-Hung; Huang, Shih-Yung; Yang, Ruei-Cheng; Sun, Jui-Sheng

    2016-07-01

    Mechanical load-induced osteogenic differentiation might be the key cellular event in the calcification and ossification of ligamentum flavum. The aim of this study was to investigate the influence of tissue transglutaminase (TGM2) on mechanical load-induced osteogenesis of ligamentum flavum cells. Human ligamentum flavum cells were obtained from 12 patients undergoing lumbar spine surgery. Osteogenic phenotypes of ligamentum flavum cells, such as alkaline phosphatase (ALP), Alizarin red-S stain, and gene expression of osteogenic makers were evaluated following the administration of mechanical load and BMP-2 treatment. The expression of TGM2 was evaluated by real-time PCR, Western blotting, and enzyme-linked immunosorbent assay (ELISA) analysis. Our results showed that mechanical load in combination with BMP-2 enhanced calcium deposition and ALP activity. Mechanical load significantly increased ALP and OC gene expression on day 3, whereas BMP-2 significantly increased ALP, OPN, and Runx2 on day 7. Mechanical load significantly induced TGM2 gene expression and enzyme activity in human ligamentum flavum cells. Exogenous TGM2 increased ALP and OC gene expression; while, inhibited TG activity significantly attenuated mechanical load-induced and TGM2-induced ALP activity. In summary, mechanical load-induced TGM2 expression and enzyme activity is involved in the progression of the calcification of ligamentum flavum.

  10. Autocrine motility factor promotes HER2 cleavage and signaling in breast cancer cells

    Science.gov (United States)

    Kho, Dhong Hyo; Nangia-Makker, Pratima; Balan, Vitaly; Hogan, Victor; Tait, Larry; Wang, Yi; Raz, Avraham

    2013-01-01

    Trastuzumab (Herceptin®) is an effective targeted therapy in HER2 overexpressing human breast carcinoma. However, many HER2-positive patients initially or eventually become resistant to this treatment, so elucidating mechanisms of trastuzumab resistance that emerge in breast carcinoma cells is clinically important. Here we show that autocrine motility factor (AMF) binds to HER2 and induces cleavage to the ectodomain-deleted and constitutively active form p95HER2. Mechanistic investigations indicated that interaction of AMF with HER2 triggers HER2 phosphorylation and metalloprotease-mediated ectodomain shedding, activating PI3K and MAPK signaling and ablating the ability of trastuzumab to inhibit breast carcinoma cell growth. Further, we found that HER2 expression and AMF secretion were inversely related in breast carcinoma cells. Based on this evidence that AMF may contribute to HER2-mediated breast cancer progression, our findings suggest that AMF-HER2 interaction might be a novel target for therapeutic management of breast cancer patients whose disease is resistant to trastuzumab. PMID:23248119

  11. Molecular Mechanisms Involved in Mesenchymal Stem Cell Migration to the Site of Acute Myocardial Infarction

    Directory of Open Access Journals (Sweden)

    Katarina Kollar

    2009-01-01

    Full Text Available Mesenchymal stem cells or multipotent mesenchymal stromal cells (both referred to as MSC have been shown in some studies to have a beneficial effect on myocardial recovery after infarct. Current strategies for MSC delivery to heart involve intravenous, intraarterial, and intramuscular delivery. Different routes of MSC delivery and a lack of knowledge of the mechanisms that MSC utilise to migrate in vivo has most likely led to the marked variations in results that have been found. This review aims to summarise the current knowledge of MSC migratory mechanisms and looks to future methods of MSC manipulation prior to delivery in order to enhance MSC migration and engraftment.

  12. [Involvement of adrenergic mechanisms in developing the nervous syndrome of high pressure and nitrogen narcosis].

    Science.gov (United States)

    Sledkov, A I; Bernarskii, K V; Shilina, M N

    1996-01-01

    Involvement of the adrenergic mediator system in central mechanisms of hyperbaric nitrogen narcosis or the high pressure nervous syndrome (NSHP) produced by nitrogen or heliox gas mixtures under increased pressure was studied in mice and rabbit experiments with the use of pharmacological substances-analyzers. Accumulated data are indicative of lack of a significant role of the adrenergic system in the NSHP genesis and a protective effect of activation of the central but not peripheric adrenergic mediation in development of the behavioural and electrophysiological symptomatics of nitrogen narcosis. Mechanisms of NSHP and nitrogen narcosis and possible principles of pharmacological correction are under discussion.

  13. Effects of Autocrine Motility Factor (AMF) on the Migration and Invasion of Glioblastoma U251 Cells and Their Mechanism%自分泌运动因子AMF对人胶质母细胞瘤U251细胞迁移、侵袭的影响及相关机制研究

    Institute of Scientific and Technical Information of China (English)

    李阳; 汤宁; 刘哲宇; 孙铮

    2016-01-01

    为了探讨自分泌运动因子(autocrine motility factor,AMF)对人胶质母细胞瘤U251细胞迁移、侵袭影响及其相关分子机制,该实验采用了RT-PCR及免疫印迹法检测RNA干扰AMF后U251细胞中AMF的表达变化;细胞划痕实验、Transwell实验分别观察了AMF干扰前后U251细胞迁移、侵袭能力的变化;免疫印记检测AMF干扰前后细胞中总Akt、p-Akt、Sox2、基质金属蛋白酶-2(matrix metalloprotein-2,MMP-2)及MMP-9蛋白水平的变化.研究结果表明,AMF成功干扰后U251细胞的迁移和侵袭能力受到抑制,p-Akt、Sox2、MMP-2和MMP-9蛋白表达水平降低.该研究表明,AMF敲低可以通过下调PI3K/Ak信号通路活性及Sox2、MMP-2和MMP-9蛋白水平,抑制人胶质母细胞瘤U251细胞迁移和侵袭.

  14. Mechanisms involved in VPAC receptors activation and regulation: lessons from pharmacological and mutagenesis studies.

    Directory of Open Access Journals (Sweden)

    Ingrid eLanger

    2012-10-01

    Full Text Available VIP plays diverse and important role in human physiology and physiopathology and their receptors constitute potential targets for the treatment of several diseases such as neurodegenerative disorder, asthma, diabetes and inflammatory diseases. This article reviews the current knowledge regarding the two VIP receptors, VPAC1 and VPAC2, with respect to mechanisms involved in receptor activation, G protein coupling, signaling, regulation and oligomerization.

  15. Clavulanic acid increases dopamine release in neuronal cells through a mechanism involving enhanced vesicle trafficking

    Science.gov (United States)

    Kost, Gina Chun; Selvaraj, Senthil; Lee, Young Bok; Kim, Deog Joong; Ahn, Chang-Ho; Singh, Brij B

    2011-01-01

    Clavulanic acid is a CNS-modulating compound with exceptional blood-brain barrier permeability and safety profile. Clavulanic acid has been proposed to have anti-depressant activity and is currently entering Phase IIb clinical trials for the treatment of Major Depressive Disorder (MDD). Studies have also shown that clavulanic acid suppresses anxiety and enhances sexual functions in rodent and primate models by a mechanism involving central nervous system (CNS) modulation, although its detailed mechanism of action has yet to be elucidated. To further examine its potential as a CNS modulating agent as well as its mechanism of action, we investigated the effects of clavulanic acid in neuronal cells. Our results indicate that clavulanic acid enhances dopamine release in PC12 and SH-SY5Y cells without affecting dopamine synthesis. Furthermore, using affinity chromatography we were able to identify two proteins, Munc18-1 and Rab4 that potentially bind to clavulanic acid and play a critical role in neurosecretion and the vesicle trafficking process. Consistent with this result, an increase in the translocation of Munc18-1 and Rab4 from the cytoplasm to the plasma membrane was observed in clavulanic acid treated cells. Overall, these data suggest that clavulanic acid enhances dopamine release in a mechanism involving Munc18-1 and Rab4 modulation and warrants further investigation of its therapeutic use in CNS disorders, such as depression. PMID:21964384

  16. Clavulanic acid increases dopamine release in neuronal cells through a mechanism involving enhanced vesicle trafficking.

    Science.gov (United States)

    Kost, Gina Chun; Selvaraj, Senthil; Lee, Young Bok; Kim, Deog Joong; Ahn, Chang-Ho; Singh, Brij B

    2011-10-24

    Clavulanic acid is a CNS-modulating compound with exceptional blood-brain barrier permeability and safety profile. Clavulanic acid has been proposed to have anti-depressant activity and is currently entering Phase IIb clinical trials for the treatment of Major Depressive Disorder (MDD). Studies have also shown that clavulanic acid suppresses anxiety and enhances sexual functions in rodent and primate models by a mechanism involving central nervous system (CNS) modulation, although its detailed mechanism of action has yet to be elucidated. To further examine its potential as a CNS modulating agent as well as its mechanism of action, we investigated the effects of clavulanic acid in neuronal cells. Our results indicate that clavulanic acid enhances dopamine release in PC12 and SH-SY5Y cells without affecting dopamine synthesis. Furthermore, using affinity chromatography we were able to identify two proteins, Munc18-1 and Rab4 that potentially bind to clavulanic acid and play a critical role in neurosecretion and the vesicle trafficking process. Consistent with this result, an increase in the translocation of Munc18-1 and Rab4 from the cytoplasm to the plasma membrane was observed in clavulanic acid treated cells. Overall, these data suggest that clavulanic acid enhances dopamine release in a mechanism involving Munc18-1 and Rab4 modulation and warrants further investigation of its therapeutic use in CNS disorders, such as depression.

  17. Evidence of involvement of central neural mechanisms in generating fibromyalgia pain.

    Science.gov (United States)

    Staud, Roland

    2002-08-01

    Fibromyalgia syndrome (FMS) is characterized by widespread pain, fatigue, sleep abnormalities, and distress. Because FMS lacks consistent evidence of tissue abnormalities, recent investigations have focused on central nervous system mechanisms of pain. Abnormal temporal summation of second pain (wind-up) and central sensitization have been described recently in patients with FMS. Wind-up and central sensitization, which rely on central pain mechanisms, occur after prolonged C-nociceptor input and depend on activation of nociceptor-specific neurons and wide dynamic range neurons in the dorsal horn of the spinal cord. Other abnormal central pain mechanisms recently detected in patients with FMS include diffuse noxious inhibitory controls. These pain inhibitory mechanisms rely on spinal cord and supraspinal systems involving pain facilitatory and pain inhibitory pathways. Brain-imaging techniques that can detect neuronal activation after nociceptive stimuli have provided additional evidence for abnormal central pain mechanisms in FMS. Brain images have corroborated the augmented reported pain experience of patients with fibromyalgia during experimental pain stimuli. In addition, thalamic activity, which contributes significantly to pain processing, was decreased in fibromyalgia. However, central pain mechanisms of fibromyalgia may not depend exclusively on neuronal activation. Neuroglial activation has been found to play an important role in the induction and maintenance of chronic pain. These findings may have important implications for future research and the treatment of fibromyalgia pain.

  18. Involvement of midbrain tectum neurokinin-mediated mechanisms in fear and anxiety

    Energy Technology Data Exchange (ETDEWEB)

    Brenes, J.C. [Experimental and Physiological Psychology, Philipps-University of Marburg, Marburg (Germany); Broiz, A.C.; Bassi, G.S. [Instituto de Neurociências e Comportamento, Campus USP, Ribeirão Preto, SP (Brazil); Laboratório de Psicobiologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Schwarting, R.K.W. [Experimental and Physiological Psychology, Philipps-University of Marburg, Marburg (Germany); Brandão, M.L. [Instituto de Neurociências e Comportamento, Campus USP, Ribeirão Preto, SP (Brazil); Laboratório de Psicobiologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil)

    2012-03-09

    Electrical stimulation of midbrain tectum structures, particularly the dorsal periaqueductal gray (dPAG) and inferior colliculus (IC), produces defensive responses, such as freezing and escape behavior. Freezing also ensues after termination of dPAG stimulation (post-stimulation freezing). These defensive reaction responses are critically mediated by {sub Y}-aminobutyric acid and 5-hydroxytryptamine mechanisms in the midbrain tectum. Neurokinins (NKs) also play a role in the mediation of dPAG stimulation-evoked fear, but how NK receptors are involved in the global processing and expression of fear at the level of the midbrain tectum is yet unclear. The present study investigated the role of NK-1 receptors in unconditioned defensive behavior induced by electrical stimulation of the dPAG and IC of male Wistar rats. Spantide (100 pmol/0.2 µL), a selective NK-1 antagonist, injected into these midbrain structures had anti-aversive effects on defensive responses and distress ultrasonic vocalizations induced by stimulation of the dPAG but not of the IC. Moreover, intra-dPAG injections of spantide did not influence post-stimulation freezing or alter exploratory behavior in rats subjected to the elevated plus maze. These results suggest that NK-1 receptors are mainly involved in the mediation of defensive behavior organized in the dPAG. Dorsal periaqueductal gray-evoked post-stimulation freezing was not affected by intra-dPAG injections of spantide, suggesting that NK-1-mediated mechanisms are only involved in the output mechanisms of defensive behavior and not involved in the processing of ascending aversive information from the dPAG.

  19. Involvement of midbrain tectum neurokinin-mediated mechanisms in fear and anxiety

    Directory of Open Access Journals (Sweden)

    J.C. Brenes

    2012-04-01

    Full Text Available Electrical stimulation of midbrain tectum structures, particularly the dorsal periaqueductal gray (dPAG and inferior colliculus (IC, produces defensive responses, such as freezing and escape behavior. Freezing also ensues after termination of dPAG stimulation (post-stimulation freezing. These defensive reaction responses are critically mediated by γ-aminobutyric acid and 5-hydroxytryptamine mechanisms in the midbrain tectum. Neurokinins (NKs also play a role in the mediation of dPAG stimulation-evoked fear, but how NK receptors are involved in the global processing and expression of fear at the level of the midbrain tectum is yet unclear. The present study investigated the role of NK-1 receptors in unconditioned defensive behavior induced by electrical stimulation of the dPAG and IC of male Wistar rats. Spantide (100 pmol/0.2 μL, a selective NK-1 antagonist, injected into these midbrain structures had anti-aversive effects on defensive responses and distress ultrasonic vocalizations induced by stimulation of the dPAG but not of the IC. Moreover, intra-dPAG injections of spantide did not influence post-stimulation freezing or alter exploratory behavior in rats subjected to the elevated plus maze. These results suggest that NK-1 receptors are mainly involved in the mediation of defensive behavior organized in the dPAG. Dorsal periaqueductal gray-evoked post-stimulation freezing was not affected by intra-dPAG injections of spantide, suggesting that NK-1-mediated mechanisms are only involved in the output mechanisms of defensive behavior and not involved in the processing of ascending aversive information from the dPAG.

  20. IL-8, a novel messenger to cross-link inflammation and tumor EMT via autocrine and paracrine pathways (Review).

    Science.gov (United States)

    Long, Xinxin; Ye, Yingnan; Zhang, Lijie; Liu, Pengpeng; Yu, Wenwen; Wei, Feng; Ren, Xiubao; Yu, Jinpu

    2016-01-01

    The epithelial-mesenchymal transition (EMT) is a process through which epithelial cells trans-differentiate and acquire an aggressive mesenchymal phenotype. In tumor cells, EMT is a vital step of tumor progression and metastasis. Amid the increasing interest in tumor EMT, only a few studies focused on the soluble mediators secreted by tumor cells passing through this phenotypic switch. In this review, we focus on the essential role of interleukin-8 (IL-8) signaling for the acquisition and maintenance of tumor EMT via direct and indirect mechanisms. Besides the autocrine loop between IL-8 and tumor cells that have gone through EMT, IL-8 could potentiate adjacent epithelial tumor cells into a mesenchymal phenotype via a paracrine mode. Moreover, understanding the role of IL-8 in EMT will provide insight into the pathogenesis of tumor progression and may facilitate the development of an effective strategy for the prevention and treatment of metastatic cancer.

  1. Phytoremediation potential of the novel atrazine tolerant Lolium multiflorum and studies on the mechanisms involved

    Energy Technology Data Exchange (ETDEWEB)

    Merini, Luciano J. [Catedra de Microbiologia Industrial y Biotecnologia, Universidad de Buenos Aires (Argentina); Bobillo, Cecilia [Servicio de Huellas Digitales Geneticas, Facultad de Farmacia y Bioquimica, Microbiologia Industrial y Biotecnologia, Universidad de Buenos Aires, Junin 956, BS As (Argentina); Cuadrado, Virginia [Catedra de Microbiologia Industrial y Biotecnologia, Universidad de Buenos Aires (Argentina); Corach, Daniel [Servicio de Huellas Digitales Geneticas, Facultad de Farmacia y Bioquimica, Microbiologia Industrial y Biotecnologia, Universidad de Buenos Aires, Junin 956, BS As (Argentina); Giulietti, Ana M., E-mail: agiule@ffyb.uba.a [Catedra de Microbiologia Industrial y Biotecnologia, Universidad de Buenos Aires (Argentina)

    2009-11-15

    Atrazine impact on human health and the environment have been extensively studied. Phytoremediation emerged as a low cost, environmental friendly biotechnological solution for atrazine pollution in soil and water. In vitro atrazine tolerance assays were performed and Lolium multiflorum was found as a novel tolerant species, able to germinate and grow in the presence of 1 mg kg{sup -1} of the herbicide. L. multiflorum presented 20% higher atrazine removal capacity than the natural attenuation, with high initial degradation rate in microcosms. The mechanisms involved in atrazine tolerance such as mutation in psbA gene, enzymatic detoxification via P{sub 450} or chemical hydrolysis through benzoxazinones were evaluated. It was demonstrated that atrazine tolerance is conferred by enhanced enzymatic detoxification via P{sub 450}. Due to its atrazine degradation capacity in soil and its agronomical properties, L. multiflorum is a candidate for designing phytoremediation strategies for atrazine contaminated agricultural soils, especially those involving run-off avoiding. - Finding of a novel atrazine-tolerant species, as a potential candidate for phytoremediating herbicide-contaminated agriculture soils and elucidation of the mechanisms involved in tolerance.

  2. Potential Mechanisms Involved in Ceramide-induced Apoptosis in Human Colon Cancer HT29 Cells

    Institute of Scientific and Technical Information of China (English)

    JING WANG; XIAO-WEN LV; YU-GUO DU

    2009-01-01

    Objective To investigate the potential mechanisms of cell death after the treatment with ceramide. Methods MTT assay,DNA ladder, reporter assay, FACS and Western blot assay were employed to investigate the potential mechanisms of cell death after the treatment with C2-ceramide. Results A short-time treatment with C2-ceramide induced cell death, which was associated with p38 MAP kinase activation, but had no links with typical caspase activation or PARP degradation. Rather than caspase inhibitor, Inhibitor of p38 MAP kinase blocked cell death induced by a short-time treatment with ceramide (12 h). Moreover, incubation of cells with ceramide for a long time (>12 h) increased subGl, but reduced S phase accompanied by caspase-dependent and caspase-independent changes including NFκB activation. Conclusion Ceramide-induced cell apoptosis involves both caspase-dependent and -independent signaling pathway. Caspase-independent cell death occurring in a relatively early stage, which is mediated via p38 MAP kinase, can progress into a stage involving both caspase-dependent and -independent mechanisms accompanied by cell signaling of MAPKs and NFκB.

  3. Review of endocrine disorders associated with environmental toxicants and possible involved mechanisms.

    Science.gov (United States)

    Maqbool, Faheem; Mostafalou, Sara; Bahadar, Haji; Abdollahi, Mohammad

    2016-01-15

    Endocrine disrupting chemicals (EDC) are released into environment from different sources. They are mainly used in packaging industries, pesticides and food constituents. Clinical evidence, experimental models, and epidemiological studies suggest that EDC have major risks for human by targeting different organs and systems in the body. Multiple mechanisms are involved in targeting the normal system, through estrogen receptors, nuclear receptors and steroidal receptors activation. In this review, different methods by which xenobiotics stimulate signaling pathways and genetic mutation or DNA methylation have been discussed. These methods help to understand the results of xenobiotic action on the endocrine system. Endocrine disturbances in the human body result in breast cancer, ovarian problems, thyroid eruptions, testicular carcinoma, Alzheimer disease, schizophrenia, nerve damage and obesity. EDC characterize a wide class of compounds such as organochlorinated pesticides, industrial wastes, plastics and plasticizers, fuels and numerous other elements that exist in the environment or are in high use during daily life. The interactions and mechanism of toxicity in relation to human general health problems, especially endocrine disturbances with particular reference to reproductive problems, diabetes, and breast, testicular and ovarian cancers should be deeply investigated. There should also be a focus on public awareness of these EDC risks and their use in routine life. Therefore, the aim of this review is to summarize all evidence regarding different physiological disruptions in the body and possible involved mechanisms, to prove the association between endocrine disruptions and human diseases.

  4. Assessment of Mechanisms Involved in Antinociception Produced by the Alkaloid Caulerpine

    Directory of Open Access Journals (Sweden)

    Luiz Henrique Agra Cavalcante-Silva

    2014-09-01

    Full Text Available In previous works we showed that oral administration of caulerpine, a bisindole alkaloid isolated from algae of the genus Caulerpa, produced antinociception when assessed in chemical and thermal models of nociception. In this study, we evaluated the possible mechanism of action of this alkaloid in mice, using the writhing test. The antinociceptive effect of caulerpine was not affected by intraperitoneal (i.p. pretreatment of mice with naloxone, flumazenil, l-arginine or atropine, thus discounting the involvement of the opioid, GABAergic, l-arginine-nitric oxide and (muscarinic cholinergic pathways, respectively. In contrast, i.p. pretreatment with yohimbine, an α2-adrenoceptor antagonist, or tropisetron, a 5-HT3 antagonist, significantly blocked caulerpine-induced antinociception. These results suggest that caulerpine exerts its antinociceptive effect in the writhing test via pathways involving α2-adrenoceptors and 5-HT3 receptors. In summary, this alkaloid could be of interest in the development of new dual-action analgesic drugs.

  5. Mechanisms Involved in the Pro-Apoptotic Effect of Melatonin in Cancer Cells

    Directory of Open Access Journals (Sweden)

    Isaac Antolín

    2013-03-01

    Full Text Available It is well established that melatonin exerts antitumoral effects in many cancer types, mostly decreasing cell proliferation at low concentrations. On the other hand, induction of apoptosis by melatonin has been described in the last few years in some particular cancer types. The cytotoxic effect occurs after its administration at high concentrations, and the molecular pathways involved have been only partially determined. Moreover, a synergistic effect has been found in several cancer types when it is administered in combination with chemotherapeutic agents. In the present review, we will summarize published work on the pro-apoptotic effect of melatonin in cancer cells and the reported mechanisms involved in such action. We will also construct a hypothesis on how different cell signaling pathways may relate each other on account for such effect.

  6. Multiple mechanisms involved in oxytocin-induced modulation of myometrial contractility

    Institute of Scientific and Technical Information of China (English)

    Anatoly SHMYGOL; Joanna GULLAM; Andrew BLANKS; Steven THORNTON

    2006-01-01

    Oxytocin is a small peptide hormone with multiple sites of action in human body.It regulates a large number of reproduction-related processes in all species.Particularly important is its ability to stimulate uterine contractility.This is achieved by multiple mechanisms involving sarcoplasmic reticulum Ca2+ release and sensitization of the contractile apparatus to Ca2+.In this paper,we review the data published by US and other groups on oxytocin-induced modulation of uterine contractility.We conclude that sensitization of contractile apparatus to Ca2+ is the most relevant physiological effect of oxytocin on human myometrium.

  7. Mechanisms regulating proteostasis are involved in sympatric speciation of the blind mole rat, Spalax galili.

    Science.gov (United States)

    Rodriguez, Karl A; Li, Kexin; Nevo, Eviatar; Buffenstein, Rochelle

    2016-01-01

    Genome-wide analysis demonstrates extensive genomic adaptive complexes involved in sympatric speciation between blind mole rats (Spalax galili) in abutting populations living in basalt and chalk soils. Among the gene ontology (GO) enrichment, musculature and metabolism stood out in basalt dwellers while nutrition and neurogenetics were highlighted in chalk residents. Measurements of mechanisms regulating protein homeostasis inspired by these GO terms suggest that at the proteomic level there is also a habitat/soil-type driven divergence with the basalt residents exhibiting higher proteasome activity whereas elevated levels of markers of autophagy are evident in the chalk inhabitants.

  8. Pathogenic Mechanisms Involved in the Hematological Alterations of Arenavirus-induced Hemorrhagic Fevers

    Directory of Open Access Journals (Sweden)

    Roberto G. Pozner

    2013-01-01

    Full Text Available Viral hemorrhagic fevers (VHFs caused by arenaviruses are acute diseases characterized by fever, headache, general malaise, impaired cellular immunity, eventual neurologic involvement, and hemostatic alterations that may ultimately lead to shock and death. The causes of the bleeding are still poorly understood. However, it is generally accepted that these causes are associated to some degree with impaired hemostasis, endothelial cell dysfunction and low platelet counts or function. In this article, we present the current knowledge about the hematological alterations present in VHF induced by arenaviruses, including new aspects on the underlying pathogenic mechanisms.

  9. Pathogenic mechanisms involved in the hematological alterations of arenavirus-induced hemorrhagic fevers.

    Science.gov (United States)

    Schattner, Mirta; Rivadeneyra, Leonardo; Pozner, Roberto G; Gómez, Ricardo M

    2013-01-21

    Viral hemorrhagic fevers (VHFs) caused by arenaviruses are acute diseases characterized by fever, headache, general malaise, impaired cellular immunity, eventual neurologic involvement, and hemostatic alterations that may ultimately lead to shock and death. The causes of the bleeding are still poorly understood. However, it is generally accepted that these causes are associated to some degree with impaired hemostasis, endothelial cell dysfunction and low platelet counts or function. In this article, we present the current knowledge about the hematological alterations present in VHF induced by arenaviruses, including new aspects on the underlying pathogenic mechanisms.

  10. A review on the molecular mechanisms involved in insulin resistance induced by organophosphorus pesticides.

    Science.gov (United States)

    Lasram, Mohamed Montassar; Dhouib, Ines Bini; Annabi, Alya; El Fazaa, Saloua; Gharbi, Najoua

    2014-08-01

    There is increasing evidence reporting that organophosphorus pesticides (OPs) impair glucose homeostasis and cause insulin resistance and type 2 diabetes. Insulin resistance is a complex metabolic disorder that defies explanation by a single etiological pathway. Formation of advanced glycation end products, accumulation of lipid metabolites, activation of inflammatory pathways and oxidative stress have all been implicated in the pathogenesis of insulin resistance. Ultimately, these molecular processes activate a series of stress pathways involving a family of serine kinases, which in turn have a negative effect on insulin signaling. Experimental and clinical data suggest an association between these molecular mechanisms and OPs compounds. It was first reported that OPs induce hyperglycemia. Then a concomitant increase of blood glucose and insulin was pointed out. For some years only, we have begun to understand that OPs promote insulin resistance and increase the risk of type 2 diabetes. Overall, this review outlines various mechanisms that lead to the development of insulin resistance by OPs exposure.

  11. Cholinergic deficiency involved in vascular dementia:possible mechanism and strategy of treatment

    Institute of Scientific and Technical Information of China (English)

    Juan WANG; Hai-yan ZHANG; Xi-can TANG

    2009-01-01

    Vascular dementia (VaD) is a progressive neurodegenerative disease with a high prevalence.Several studies have recently reported that VaD patients present cholinergic deficits in the brain and cerebrospinal fluid (CSF) that may be closely related to the pathophysiology of cognitive impairment.Moreover,cholinergic therapies have shown promising effects on cognitive improvement in VaD patients.The precise mechanisms of these cholinergic agents are currently not fully understood;however,accumulating evidence indicates that these drugs may act through the cholinergic anti-inflammatory pathway,in which the efferent vagus nerve signals suppress pro-inflammatory cytokine release and inhibit inflammation,although regulation of oxidative stress and energy metabolism,alleviation of apoptosis may also be involved.In this paper,we provide a brief overview of the cholinergic treatment strategy for VaD and its relevant mechanisms of anti-inflammation.

  12. Mechanism of electron transfer reaction of ternary dipicolinatochromium(III) complex involving oxalate as secondary ligand

    Indian Academy of Sciences (India)

    Hassan Amroun Ewais; Iqbal Mohamed Ibrhium Ismail

    2013-09-01

    Mechanism of electron transfer reaction of ternary Mechanism of the oxidation of [CrIII(DPA)(OX)(H2O)]− (DPA = dipicolinate and OX = oxalate) by periodate in aqueous acidic medium has been studied spectrophotometrically over the pH range of 4.45-5.57 at different temperatures. The reaction is first order with respect to both [IO$^{−}_{4}$] and the complex concentration, and it obeys the following rate law: $$d[{\\text Cr}^{\\text{VI}}]/dt = k_6K_4K_6[{\\text IO}^−_4][{\\text{Cr}}^{\\text{III}}]_{\\text{T}}/\\{([H^+] + K_4) + (K_5[H+] + K_6K_4)[{\\text{IO}}^{−}_{4}]\\}.$$ The rate of the reaction increases with increasing pH due to the deprotonation equilibria of the complex. The experimental rate law is consistent with a mechanism in which the deprotonated form [CrIII(DPA)(OX)(OH)]2− is more reactive than the conjugated acid. It is proposed that electron transfer proceeds through an inner-sphere mechanism via coordination of IO$^{−}_{4}$ to chromium(III). Thermodynamic activation parameters were calculated using the transition state theory equation.dipicolinatochromium(III) complex involving oxalate as secondary ligand

  13. The mechanism of sperm-egg interaction and the involvement of IZUM01 in fusion

    Institute of Scientific and Technical Information of China (English)

    Naokazu Inoue; Masahito Ikawa; Masaru Okabe

    2011-01-01

    An average human ejaculate contains over 100 million sperm,but only a few succeed in accomplishing the journey to an egg by migration through the female reproductive tract.Among these few sperm,only one participates in fertilization.There might be an ingenious molecular mechanism to ensure that the very best sperm fertilize an egg.However,recent gene disruption experiments in mice have revealed that many factors previously described as important for fertilization are largely dispensable.One could argue that the fertilization mechanism is made robust against gene disruptions.However,this is not likely,as there are already six different gene-disrupted mouse lines (Calmegin,Adam1a,Adam2,Adam3,Aceand Pgap1),all of which result in male sterility.The sperm from these animals are known to have defective zona-binding ability and at the same time lose oviduct-migrating ability.Concerning spermzona binding,the widely accepted involvement of sugar moiety on zona pellucida 3 (ZP3) is indicated to be dispensable by gene disruption experiments.Thus,the landscape of the mechanism of fertilization is revolving considerably.In the sperm-egg fusion process,CD9 on egg and IZUM01 on sperm have emerged as essential factors.This review focuses on the mechanism of fertilization elucidated by gene-manipulated animals.

  14. The mechanism of sperm-egg interaction and the involvement of IZUMO1 in fusion.

    Science.gov (United States)

    Inoue, Naokazu; Ikawa, Masahito; Okabe, Masaru

    2011-01-01

    An average human ejaculate contains over 100 million sperm, but only a few succeed in accomplishing the journey to an egg by migration through the female reproductive tract. Among these few sperm, only one participates in fertilization. There might be an ingenious molecular mechanism to ensure that the very best sperm fertilize an egg. However, recent gene disruption experiments in mice have revealed that many factors previously described as important for fertilization are largely dispensable. One could argue that the fertilization mechanism is made robust against gene disruptions. However, this is not likely, as there are already six different gene-disrupted mouse lines (Calmegin, Adam1a, Adam2, Adam3, Ace and Pgap1), all of which result in male sterility. The sperm from these animals are known to have defective zona-binding ability and at the same time lose oviduct-migrating ability. Concerning sperm-zona binding, the widely accepted involvement of sugar moiety on zona pellucida 3 (ZP3) is indicated to be dispensable by gene disruption experiments. Thus, the landscape of the mechanism of fertilization is revolving considerably. In the sperm-egg fusion process, CD9 on egg and IZUMO1 on sperm have emerged as essential factors. This review focuses on the mechanism of fertilization elucidated by gene-manipulated animals.

  15. Autocrine/paracrine proliferative effect of ovarian GH and IGF-I in chicken granulosa cell cultures.

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    Ahumada-Solórzano, S Marisela; Martínez-Moreno, Carlos G; Carranza, Martha; Ávila-Mendoza, José; Luna-Acosta, José Luis; Harvey, Steve; Luna, Maricela; Arámburo, Carlos

    2016-08-01

    It is known that growth hormone (GH) and its receptor (GHR) are expressed in granulosa cells (GC) and thecal cells during the follicular development in the hen ovary, which suggests GH is involved in autocrine/paracrine actions in the female reproductive system. In this work, we show that the knockdown of local ovarian GH with a specific cGH siRNA in GC cultures significantly decreased both cGH mRNA expression and GH secretion to the media, and also reduced their proliferative rate. Thus, we analyzed the effect of ovarian GH and recombinant chicken GH (rcGH) on the proliferation of pre-hierarchical GCs in primary cultures. Incubation of GCs with either rcGH or conditioned media, containing predominantly a 15-kDa GH isoform, showed that both significantly increased proliferation as determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, proliferating cell nuclear antigen (PCNA) quantification and ((3)H)-thymidine incorporation ((3)H-T) assays in a dose response fashion. Both, locally produced GH and rcGH also induced the phosphorylation of Erk1/2 in GC cultures. Furthermore, GH increased IGF-I synthesis and its release into the GC culture incubation media. These results suggest that GH may act through local IGF-I to induce GC proliferation, since IGF-I immunoneutralization completely abolished the GH-induced proliferative effect. These data suggest that GH and IGF-I may play a role as autocrine/paracrine regulators during the follicular development in the hen ovary at the pre-hierarchical stage.

  16. Astrocytes are involved in trigeminal dynamic mechanical allodynia: potential role of D-serine.

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    Dieb, W; Hafidi, A

    2013-09-01

    Trigeminal neuropathic pain affects millions of people worldwide. Despite decades of study on the neuronal processing of pain, mechanisms underlying enhanced pain states after injury remain unclear. N-methyl-D-aspartate (NMDA) receptor-dependent changes play a critical role in triggering central sensitization in neuropathic pain. These receptors are regulated at the glycine site through a mandatory endogenous co-agonist D-serine, which is synthesized by astrocytes. Therefore, the present study was carried out to determine whether astrocytes are involved, through D-serine secretion, in dynamic mechanical allodynia (DMA) obtained after chronic constriction of the infraorbital nerve (CCI-IoN) in rats. Two weeks after CCI-IoN, an important reaction of astrocytes was present in the medullary dorsal horn (MDH), as revealed by an up-regulation of glial fibrillary acidic protein (GFAP) in allodynic rats. In parallel, an increase in D-serine synthesis, which co-localized with its synthesis enzyme serine racemase, was strictly observed in astrocytes. Blocking astrocyte metabolism by intracisternal delivery of fluorocitrate alleviated DMA. Furthermore, the administration of D-amino-acid oxidase (DAAO), a D-serine-degrading enzyme, or that of L-serine O-sulfate (LSOS), a serine racemase inhibitor, significantly decreased pain behavior in allodynic rats. These results demonstrate that astrocytes are involved in the modulation of orofacial post-traumatic neuropathic pain via the release of the gliotransmitter D-serine.

  17. Antinociceptive Activity of Methanol Extract of Muntingia calabura Leaves and the Mechanisms of Action Involved

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    M. H. Mohd. Sani

    2012-01-01

    Full Text Available Muntingia calabura L. (family Elaeocarpaceae has been traditionally used to relieve various pain-related ailments. The present study aimed to determine the antinociceptive activity of methanol extract of M. calabura leaves (MEMC and to elucidate the possible mechanism of antinociception involved. The in vivo chemicals (acetic acid-induced abdominal constriction and formalin-, capsaicin-, glutamate-, serotonin-induced paw licking test and thermal (hot plate test models of nociception were used to evaluate the extract antinociceptive activity. The extract (100, 250, and 500 mg/kg was administered orally 60 min prior to subjection to the respective test. The results obtained demonstrated that MEMC produced significant (P<0.05 antinociceptive response in all the chemical- and thermal-induced nociception models, which was reversed after pretreatment with 5 mg/kg naloxone, a non-selective opioid antagonist. Furthermore, pretreatment with L-arginine (a nitric oxide (NO donor, NG-nitro-L-arginine methyl esters (L-NAME; an inhibitor of NO synthase (NOS, methylene blue (MB; an inhibitor of cyclic-guanosine monophosphate (cGMP pathway, or their combination also caused significant (P<0.05 change in the intensity of the MEMC antinociception. In conclusion, the MEMC antinociceptive activity involves activation of the peripheral and central mechanisms, and modulation via, partly, the opioid receptors and NO/cGMP pathway.

  18. Mechanism involved in phagocytosis and killing of Listeria monocytogenes by Acanthamoeba polyphaga.

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    Akya, Alisha; Pointon, Andrew; Thomas, Connor

    2009-10-01

    Intra-cellular pathogen, Listeria monocytogenes, is capable of invasion and survival within mammalian cells. However, Acanthamoeba polyphaga trophozoites phagocytose and rapidly degrade Listeria cells. In order to provide more information on amoeba phagocytosis and killing mechanisms, this study used several inhibitor agents known to affect the phagocytosis and killing of bacteria by eukaryotes. Amoebae were pre-treated with mannose, cytochalasin D, wortmannin, suramin, ammonium chloride, bafilomycin A and monensin followed by co-culture with bacteria. Phagocytosis and killing of bacterial cells by amoeba trophozoites was assessed using plate counting methods and microscopy. The data presented indicates that actin polymerisation and cytoskeletal rearrangement are involved in phagocytosis of L. monocytogenes cells by A. polyphaga trophozoites. Further, both phagosomal acidification and phagosome-lysosome fusion are involved in killing and degradation of L. monocytogenes cells by A. polyphaga. However, the mannose-binding protein receptor does not play an important role in uptake of bacteria by amoeba trophozoites. In conclusion, this data reveals the similar principles of molecular mechanisms used by different types of eukaryotes in uptake and killing of bacteria.

  19. Mechanisms and neuronal networks involved in reactive and proactive cognitive control of interference in working memory.

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    Irlbacher, Kerstin; Kraft, Antje; Kehrer, Stefanie; Brandt, Stephan A

    2014-10-01

    Cognitive control can be reactive or proactive in nature. Reactive control mechanisms, which support the resolution of interference, start after its onset. Conversely, proactive control involves the anticipation and prevention of interference prior to its occurrence. The interrelation of both types of cognitive control is currently under debate: Are they mediated by different neuronal networks? Or are there neuronal structures that have the potential to act in a proactive as well as in a reactive manner? This review illustrates the way in which integrating knowledge gathered from behavioral studies, functional imaging, and human electroencephalography proves useful in answering these questions. We focus on studies that investigate interference resolution at the level of working memory representations. In summary, different mechanisms are instrumental in supporting reactive and proactive control. Distinct neuronal networks are involved, though some brain regions, especially pre-SMA, possess functions that are relevant to both control modes. Therefore, activation of these brain areas could be observed in reactive, as well as proactive control, but at different times during information processing.

  20. Estradiol decreases cortical reactive astrogliosis after brain injury by a mechanism involving cannabinoid receptors.

    Science.gov (United States)

    López Rodríguez, Ana Belén; Mateos Vicente, Beatriz; Romero-Zerbo, Silvana Y; Rodriguez-Rodriguez, Noé; Bellini, María José; Rodriguez de Fonseca, Fernando; Bermudez-Silva, Francisco Javier; Azcoitia, Iñigo; Garcia-Segura, Luis M; Viveros, María-Paz

    2011-09-01

    The neuroactive steroid estradiol reduces reactive astroglia after brain injury by mechanisms similar to those involved in the regulation of reactive gliosis by endocannabinoids. In this study, we have explored whether cannabinoid receptors are involved in the effects of estradiol on reactive astroglia. To test this hypothesis, the effects of estradiol, the cannabinoid CB1 antagonist/inverse agonist AM251, and the cannabinoid CB2 antagonist/inverse agonist AM630 were assessed in the cerebral cortex of male rats after a stab wound brain injury. Estradiol reduced the number of vimentin immunoreactive astrocytes and the number of glial fibrillary acidic protein immunoreactive astrocytes in the proximity of the wound. The effect of estradiol was significantly inhibited by the administration of either CB1 or CB2 receptor antagonists. The effect of estradiol may be in part mediated by alterations in endocannabinoid signaling because the hormone increased in the injured cerebral cortex the messenger RNA levels of CB2 receptors and of some of the enzymes involved in the synthesis and metabolism of endocannabinoids. These findings suggest that estradiol may decrease reactive astroglia in the injured brain by regulating the activity of the endocannabinoid system.

  1. Novel mechanisms of sildenafil in pulmonary hypertension involving cytokines/chemokines, MAP kinases and Akt.

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    Tamas Kiss

    Full Text Available Pulmonary arterial hypertension (PH is associated with high mortality due to right ventricular failure and hypoxia, therefore to understand the mechanism by which pulmonary vascular remodeling initiates these processes is very important. We used a well-characterized monocrotaline (MCT-induced rat PH model, and analyzed lung morphology, expression of cytokines, mitogen-activated protein kinase (MAPK phosphorylation, and phosphatidylinositol 3-kinase-Akt (PI-3k-Akt pathway and nuclear factor (NF-κB activation in order to elucidate the mechanisms by which sildenafil's protective effect in PH is exerted. Besides its protective effect on lung morphology, sildenafil suppressed multiple cytokines involved in neutrophil and mononuclear cells recruitment including cytokine-induced neutrophil chemoattractant (CINC-1, CINC-2α/β, tissue inhibitor of metalloproteinase (TIMP-1, interleukin (IL-1α, lipopolysaccharide induced CXC chemokine (LIX, monokine induced by gamma interferon (MIG, macrophage inflammatory protein (MIP-1α, and MIP-3α. NF-κB activation and phosphorylation were also attenuated by sildenafil. Furthermore, sildenafil reduced extracellular signal-regulated kinase (ERK1/2 and p38 MAPK activation while enhanced activation of the cytoprotective Akt pathway in PH. These data suggest a beneficial effect of sildenafil on inflammatory and kinase signaling mechanisms that substantially contribute to its protective effects, and may have potential implications in designing future therapeutic strategies in the treatment of pulmonary hypertension.

  2. Mechanisms involved in the nociception triggered by the venom of the armed spider Phoneutria nigriventer.

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    Camila Gewehr

    Full Text Available BACKGROUND: The frequency of accidental spider bites in Brazil is growing, and poisoning due to bites from the spider genus Phoneutria nigriventer is the second most frequent source of such accidents. Intense local pain is the major symptom reported after bites of P. nigriventer, although the mechanisms involved are still poorly understood. Therefore, the aim of this study was to identify the mechanisms involved in nociception triggered by the venom of Phoneutria nigriventer (PNV. METHODOLOGY/PRINCIPAL FINDINGS: Twenty microliters of PNV or PBS was injected into the mouse paw (intraplantar, i.pl.. The time spent licking the injected paw was considered indicative of the level of nociception. I.pl. injection of PNV produced spontaneous nociception, which was reduced by arachnid antivenin (ArAv, local anaesthetics, opioids, acetaminophen and dipyrone, but not indomethacin. Boiling or dialysing the venom reduced the nociception induced by the venom. PNV-induced nociception is not dependent on glutamate or histamine receptors or on mast cell degranulation, but it is mediated by the stimulation of sensory fibres that contain serotonin 4 (5-HT4 and vanilloid receptors (TRPV1. We detected a kallikrein-like kinin-generating enzyme activity in tissue treated with PNV, which also contributes to nociception. Inhibition of enzymatic activity or administration of a receptor antagonist for kinin B2 was able to inhibit the nociception induced by PNV. PNV nociception was also reduced by the blockade of tetrodotoxin-sensitive Na(+ channels, acid-sensitive ion channels (ASIC and TRPV1 receptors. CONCLUSION/SIGNIFICANCE: Results suggest that both low- and high-molecular-weight toxins of PNV produce spontaneous nociception through direct or indirect action of kinin B2, TRPV1, 5-HT4 or ASIC receptors and voltage-dependent sodium channels present in sensory neurons but not in mast cells. Understanding the mechanisms involved in nociception caused by PNV are of

  3. Genes and mechanisms involved in beta-amyloid generation and Alzheimer's disease.

    Science.gov (United States)

    Steiner, H; Capell, A; Leimer, U; Haass, C

    1999-01-01

    Alzheimer's disease is characterized by the invariable accumulation of senile plaques that are predominantly composed of amyloid beta-peptide (Abeta). Abeta is generated by proteolytic processing of the beta-amyloid precursor protein (betaAPP) involving the combined action of beta- and gamma-secretase. Cleavage within the Abeta domain by alpha-secretase prevents Abeta generation. In some very rare cases of familial AD (FAD), mutations have been identified within the betaAPP gene. These mutations are located close to or at the cleavage sites of the secretases and pathologically effect betaAPP processing by increasing Abeta production, specifically its highly amyloidogenic 42 amino acid variant (Abeta42). Most of the mutations associated with FAD have been identified in the two presenilin (PS) genes, particularly the PS1 gene. Like the mutations identified within the betaAPP gene, mutations in PS1 and PS2 cause the increased generation of Abeta42. PS1 has been shown to be functionally involved in Notch signaling, a key process in cellular differentation, and in betaAPP processing. A gene knock out of PS1 in mice leads to an embryonic lethal phenotype similar to that of mice lacking Notch. In addition, absence of PS1 results in reduced gamma-secretase cleavage and leads to an accumulation of betaAPP C-terminal fragments and decreased amounts of Abeta. Recent work may suggest that PS1 could be the gamma-secretase itself, exhibiting the properties of a novel aspartyl protease. Mutagenesis of either of two highly conserved intramembraneous aspartate residues of PS1 leads to reduced Abeta production as observed in the PS1 knockout. A corresponding mutation in PS2 interfered with betaAPP processing and Notch signaling suggesting a functional redundancy of both presenilins. In this issue, some of the recent work on the molecular mechanisms involved in Alzheimer's disease (AD) as well as novel diagnostic approaches and risk factors for AD will be discussed. In the first

  4. Peptide Bond Synthesis by a Mechanism Involving an Enzymatic Reaction and a Subsequent Chemical Reaction.

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    Abe, Tomoko; Hashimoto, Yoshiteru; Zhuang, Ye; Ge, Yin; Kumano, Takuto; Kobayashi, Michihiko

    2016-01-22

    We recently reported that an amide bond is unexpectedly formed by an acyl-CoA synthetase (which catalyzes the formation of a carbon-sulfur bond) when a suitable acid and l-cysteine are used as substrates. DltA, which is homologous to the adenylation domain of nonribosomal peptide synthetase, belongs to the same superfamily of adenylate-forming enzymes, which includes many kinds of enzymes, including the acyl-CoA synthetases. Here, we demonstrate that DltA synthesizes not only N-(d-alanyl)-l-cysteine (a dipeptide) but also various oligopeptides. We propose that this enzyme catalyzes peptide synthesis by the following unprecedented mechanism: (i) the formation of S-acyl-l-cysteine as an intermediate via its "enzymatic activity" and (ii) subsequent "chemical" S → N acyl transfer in the intermediate, resulting in peptide formation. Step ii is identical to the corresponding reaction in native chemical ligation, a method of chemical peptide synthesis, whereas step i is not. To the best of our knowledge, our discovery of this peptide synthesis mechanism involving an enzymatic reaction and a subsequent chemical reaction is the first such one to be reported. This new process yields peptides without the use of a thioesterified fragment, which is required in native chemical ligation. Together with these findings, the same mechanism-dependent formation of N-acyl compounds by other members of the above-mentioned superfamily demonstrated that all members most likely form peptide/amide compounds by using this novel mechanism. Each member enzyme acts on a specific substrate; thus, not only the corresponding peptides but also new types of amide compounds can be formed.

  5. Coral bleaching under thermal stress: putative involvement of host/symbiont recognition mechanisms

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    Tambutte Sylvie

    2009-08-01

    Full Text Available Abstract Background Coral bleaching can be defined as the loss of symbiotic zooxanthellae and/or their photosynthetic pigments from their cnidarian host. This major disturbance of reef ecosystems is principally induced by increases in water temperature. Since the beginning of the 1980s and the onset of global climate change, this phenomenon has been occurring at increasing rates and scales, and with increasing severity. Several studies have been undertaken in the last few years to better understand the cellular and molecular mechanisms of coral bleaching but the jigsaw puzzle is far from being complete, especially concerning the early events leading to symbiosis breakdown. The aim of the present study was to find molecular actors involved early in the mechanism leading to symbiosis collapse. Results In our experimental procedure, one set of Pocillopora damicornis nubbins was subjected to a gradual increase of water temperature from 28°C to 32°C over 15 days. A second control set kept at constant temperature (28°C. The differentially expressed mRNA between the stressed states (sampled just before the onset of bleaching and the non stressed states (control were isolated by Suppression Subtractive Hybridization. Transcription rates of the most interesting genes (considering their putative function were quantified by Q-RT-PCR, which revealed a significant decrease in transcription of two candidates six days before bleaching. RACE-PCR experiments showed that one of them (PdC-Lectin contained a C-Type-Lectin domain specific for mannose. Immunolocalisation demonstrated that this host gene mediates molecular interactions between the host and the symbionts suggesting a putative role in zooxanthellae acquisition and/or sequestration. The second gene corresponds to a gene putatively involved in calcification processes (Pdcyst-rich. Its down-regulation could reflect a trade-off mechanism leading to the arrest of the mineralization process under stress

  6. Involvement of endothelium-dependent and -independent mechanisms in midazolam-induced vasodilation.

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    Colussi, Gian Luca; Di Fabio, Alessandro; Catena, Cristiana; Chiuch, Alessandra; Sechi, Leonardo A

    2011-08-01

    Benzodiazepine (BDZ) infusion has been shown to reduce blood pressure in both humans and animals. Although the inhibitory effects of BDZ on the central nervous system have been well documented, less is known about the direct effects of BDZ on the vascular bed. The aims of this study were to assess the effects of the BDZ midazolam on the vascular system in C57/BL6 mouse aortic rings and to investigate the mechanisms of its direct vascular action. We found that midazolam induced reversible, dose-dependent vasodilation in potassium- and phenylephrine-precontracted rings. In rings that were precontracted with potassium or phenylephrine, treatment with 10 μmol l(-1) midazolam increased vasodilation by 15 and 60%, respectively, compared with baseline. Vasodilation increased by 80 and 87%, respectively, after treatment with 50 μmol l(-1) midazolam. Only the low concentration of midazolam (10 μmol l(-1)) induced endothelium-dependent vasodilation in phenylephrine-precontracted rings. Vasodilation increased by 60% in rings with endothelium and by 20% in rings without endothelium. Conversely, only the high concentration of midazolam (50 μmol l(-1)) reduced the CaCl(2)-induced vasoconstriction of aortic rings with EC(50) (the concentration giving 50% of the maximal effect) values of 1 and 6 mmol l(-1) for vehicle- and midazolam-treated rings, respectively. Furthermore, the incubation of phenylephrine-precontracted rings with an inhibitor of the nitric oxide synthase (NOS) NG-nitro-L-arginine methyl ester or the inhibitors of central or peripheral type BDZ receptors (flumazenil or PK 11195, respectively) produced no change in midazolam-induced vasodilation. Thus, low concentrations of midazolam induce vasodilation via an endothelium-dependent mechanism that does not involve NO production. In contrast, high concentrations of midazolam induce vasodilation via an endothelium-independent mechanism that implies reduced sensitivity of aortic rings to calcium ions. Additionally

  7. Molecular Mechanisms Involved in the Antitumor Activity of Cannabinoids on Gliomas: Role for Oxidative Stress

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    Paola Massi

    2010-05-01

    Full Text Available Cannabinoids, the active components of Cannabis sativa, have been shown to exert antiproliferative and proapoptotic effects on a wide spectrum of tumor cells and tissues. Of interest, cannabinoids have displayed great potency in reducing the growth of glioma tumors, one of the most aggressive CNS tumors, either in vitro or in animal experimental models curbing the growth of xenografts generated by subcutaneous or intrathecal injection of glioma cells in immune-deficient mice. Cannabinoids appear to be selective antitumoral agents as they kill glioma cells without affecting the viability of non-transformed cells. This review will summarize the anti-cancer properties that cannabinoids exert on gliomas and discuss their potential action mechanisms that appear complex, involving modulation of multiple key cell signaling pathways and induction of oxidative stress in glioma cells.

  8. Molecular Mechanisms Involved in the Antitumor Activity of Cannabinoids on Gliomas: Role for Oxidative Stress

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    Massi, Paola [Department of Pharmacology, Chemotherapy and Toxicology, University of Milan, Via Vanvitelli 32, 20129 Milan (Italy); Valenti, Marta; Solinas, Marta; Parolaro, Daniela, E-mail: daniela.parolaro@uninsubria.it [Department of Structural and Functional Biology, Section of Pharmacology, Center of Neuroscience, University of Insubria, Via A. da Giussano 10, 20152 Busto Arsizio, Varese (Italy)

    2010-05-26

    Cannabinoids, the active components of Cannabis sativa, have been shown to exert antiproliferative and proapoptotic effects on a wide spectrum of tumor cells and tissues. Of interest, cannabinoids have displayed great potency in reducing the growth of glioma tumors, one of the most aggressive CNS tumors, either in vitro or in animal experimental models curbing the growth of xenografts generated by subcutaneous or intrathecal injection of glioma cells in immune-deficient mice. Cannabinoids appear to be selective antitumoral agents as they kill glioma cells without affecting the viability of non-transformed cells. This review will summarize the anti-cancer properties that cannabinoids exert on gliomas and discuss their potential action mechanisms that appear complex, involving modulation of multiple key cell signaling pathways and induction of oxidative stress in glioma cells.

  9. Spinal toll like receptor 3 is involved in chronic pancreatitis-induced mechanical allodynia of rat

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    Feng Quan-Xing

    2011-02-01

    Full Text Available Abstract Background Mechanisms underlying pain in chronic pancreatitis (CP are incompletely understood. Our previous data showed that astrocytes were actively involved. However, it was unclear how astrocytic activation was induced in CP conditions. In the present study, we hypothesized that toll-like receptors (TLRs were involved in astrocytic activation and pain behavior in CP-induced pain. Results To test our hypothesis, we first investigated the changes of TLR2-4 in the rat CP model induced by intrapancreatic infusion of trinitrobenzene sulfonic acid (TNBS. Western blot showed that after TNBS infusion, TLR3, but not TLR2 or TLR4, was increased gradually and maintained at a very high level for up to 5 w, which correlated with the changing course of mechanical allodynia. Double immunostaining suggested that TLR3 was highly expressed on astrocytes. Infusion with TLR3 antisense oligodeoxynucleotide (ASO dose-dependently attenuated CP-induced allodynia. CP-induced astrocytic activation in the spinal cord was also significantly suppressed by TLR3 ASO. Furthermore, real-time PCR showed that IL-1β, TNF-α, IL-6 and monocyte chemotactic protein-1 (MCP-1 were significantly increased in spinal cord of pancreatic rats. In addition, TLR3 ASO significantly attenuated CP-induced up-regulation of IL-1β and MCP-1. Conclusions These results suggest a probable "TLR3-astrocytes-IL-1β/MCP-1" pathway as a positive feedback loop in the spinal dorsal horn in CP conditions. TLR3-mediated neuroimmune interactions could be new targets for treating persistent pain in CP patients.

  10. Molecular characterization of HIV-1 subtype C gp-120 regions potentially involved in virus adaptive mechanisms.

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    Alessandra Cenci

    Full Text Available The role of variable regions of HIV-1 gp120 in immune escape of HIV has been investigated. However, there is scant information on how conserved gp120 regions contribute to virus escaping. Here we have studied how molecular sequence characteristics of conserved C3, C4 and V3 regions of clade C HIV-1 gp120 that are involved in HIV entry and are target of the immune response, are modulated during the disease course. We found an increase of "shifting" putative N-glycosylation sites (PNGSs in the α2 helix (in C3 and in C4 and an increase of sites under positive selection pressure in the α2 helix during the chronic stage of disease. These sites are close to CD4 and to co-receptor binding sites. We also found a negative correlation between electric charges of C3 and V4 during the late stage of disease counteracted by a positive correlation of electric charges of α2 helix and V5 during the same stage. These data allow us to hypothesize possible mechanisms of virus escape involving constant and variable regions of gp120. In particular, new mutations, including new PNGSs occurring near the CD4 and CCR5 binding sites could potentially affect receptor binding affinity and shield the virus from the immune response.

  11. Autocrine stimulation of osteoblast activity by Wnt5a in response to TNF-α in human mesenchymal stem cells

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    Briolay, A. [ICBMS, UMR CNRS 5246, University of Lyon 1, Bâtiment Raulin, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex (France); Lencel, P. [Physiopathology of Inflammatory Bone Diseases, EA4490, ULCO. Quai Masset, Bassin Napoléon BP120, 62327 Boulogne/Mer (France); Bessueille, L. [ICBMS, UMR CNRS 5246, University of Lyon 1, Bâtiment Raulin, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex (France); Caverzasio, J. [Service of Bone Diseases, Department of Internal Medicine Specialties, University Hospital of Geneva, CH-1211 Geneva 14 (Switzerland); Buchet, R. [ICBMS, UMR CNRS 5246, University of Lyon 1, Bâtiment Raulin, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex (France); Magne, D., E-mail: david.magne@univ-lyon1.fr [ICBMS, UMR CNRS 5246, University of Lyon 1, Bâtiment Raulin, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex (France)

    2013-01-18

    Highlights: ► Ankylosing spondylitis (AS) leads to bone fusions and ankylosis. ► TNF-α stimulates osteoblasts through growth factors in AS. ► We compare the involvement of canonical vs non-canonical Wnt signaling. ► Canonical Wnt signaling is not involved in TNF-α effects in differentiating hMSCs. ► TNF-α stimulates osteoblasts through Wnt5a autocrine secretion in hMSCs. -- Abstract: Although anti-tumor necrosis factor (TNF)-α treatments efficiently block inflammation in ankylosing spondylitis (AS), they are inefficient to prevent excessive bone formation. In AS, ossification seems more prone to develop in sites where inflammation has resolved following anti-TNF therapy, suggesting that TNF-α indirectly stimulates ossification. In this context, our objectives were to determine and compare the involvement of Wnt proteins, which are potent growth factors of bone formation, in the effects of TNF-α on osteoblast function. In human mesenchymal stem cells (MSCs), TNF-α significantly increased the levels of Wnt10b and Wnt5a. Associated with this effect, TNF-α stimulated tissue-non specific alkaline phosphatase (TNAP) and mineralization. This effect was mimicked by activation of the canonical β-catenin pathway with either anti-Dkk1 antibodies, lithium chloride (LiCl) or SB216763. TNF-α reduced, and activation of β-catenin had little effect on expression of osteocalcin, a late marker of osteoblast differentiation. Surprisingly, TNF-α failed to stabilize β-catenin and Dkk1 did not inhibit TNF-α effects. In fact, Dkk1 expression was also enhanced in response to TNF-α, perhaps explaining why canonical signaling by Wnt10b was not activated by TNF-α. However, we found that Wnt5a also stimulated TNAP in MSCs cultured in osteogenic conditions, and increased the levels of inflammatory markers such as COX-2. Interestingly, treatment with anti-Wnt5a antibodies reduced endogenous TNAP expression and activity. Collectively, these data suggest that increased

  12. Mechanisms involved in ceramide-induced cell cycle arrest in human hepatocarcinoma cells

    Institute of Scientific and Technical Information of China (English)

    Jing Wang; Xiao-Wen Lv; Jie-Ping Shi; Xiao-Song Hu

    2007-01-01

    AIM:To investigate the effect of ceramide on the cell cycle in human hepatocarcinoma Bel7402 cells.Possible molecular mechanisms were explored.METHODS:[3-(4,5)-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide(MTT)assay,plasmid transfection,reporter assay,FACS and Western blotting analyses were employed to investigate the effect and the related molecular mechanisms of C2-ceramide on the cell cycle of Bel7402 cells.RESULTS:C2-ceramide was found to inhibit the growth of Bel7402 cells by inducing cell cycle arrest.During the process,the expression of p21 protein increased,while that of cyclinD1,phospho-ERK1/2 and c-myc decreased.Furthermore,the level of CDK7 was downregulated,while the transcriptional activity of PPARγ was upregulated.Addition of GW9662,which is a PPARγ specific antagonist,could reserve the modulation action on CDK7.CONCLUSION:Our results support the hypothesis that cell cycle arrest induced by C2-ceramide may be mediated via accumulation of p21 and reduction of cyclinD1 and CDK7,at least partly,through PPARγ activation.The ERK signaling pathway was involved in this process.

  13. A non-cardiomyocyte autonomous mechanism of cardioprotection involving the SLO1 BK channel

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    Andrew P. Wojtovich

    2013-03-01

    Full Text Available Opening of BK-type Ca2+ activated K+ channels protects the heart against ischemia-reperfusion (IR injury. However, the location of BK channels responsible for cardioprotection is debated. Herein we confirmed that openers of the SLO1 BK channel, NS1619 and NS11021, were protective in a mouse perfused heart model of IR injury. As anticipated, deletion of the Slo1 gene blocked this protection. However, in an isolated cardiomyocyte model of IR injury, protection by NS1619 and NS11021 was insensitive to Slo1 deletion. These data suggest that protection in intact hearts occurs by a non-cardiomyocyte autonomous, SLO1-dependent, mechanism. In this regard, an in-situ assay of intrinsic cardiac neuronal function (tachycardic response to nicotine revealed that NS1619 preserved cardiac neurons following IR injury. Furthermore, blockade of synaptic transmission by hexamethonium suppressed cardioprotection by NS1619 in intact hearts. These results suggest that opening SLO1 protects the heart during IR injury, via a mechanism that involves intrinsic cardiac neurons. Cardiac neuronal ion channels may be useful therapeutic targets for eliciting cardioprotection.

  14. Seismic behavior and mechanism analysis of innovative precast shear wall involving vertical joints

    Institute of Scientific and Technical Information of China (English)

    孙建; 邱洪兴

    2015-01-01

    To study the seismic performance and load-transferring mechanism of an innovative precast shear wall (IPSW) involving vertical joints, an experimental investigation and theoretical analysis were successively conducted on two test walls. The test results confirm the feasibility of the novel joints as well as the favorable seismic performance of the walls, even though certain optimization measures should be taken to improve the ductility. The load-transferring mechanism subsequently is theoretically investigated based on the experimental study. The theoretical results show the load-transferring route of the novel joints is concise and definite. During the elastic stage, the vertical shear stress in the connecting steel frame (CSF) distributes uniformly;and each high-strength bolt (HSB) primarily delivers vertical shear force. However, the stress in the CSF redistributes when the walls develop into the elastic-plastic stage. At the ultimate state, the vertical shear stress and horizontal normal stress in the CSF distribute linearly;and the HSBs at both ends of the CSF transfer the maximum shear forces.

  15. Exploring the temporal mechanism involved in the pitch of unresolved harmonics.

    Science.gov (United States)

    Kaernbach, C; Bering, C

    2001-08-01

    This paper continues a line of research initiated by Kaernbach and Demany [J. Acoust. Soc. Am. 104, 2298-2306 (1998)], who employed filtered click sequences to explore the temporal mechanism involved in the pitch of unresolved harmonics. In a first experiment, the just noticeable difference (jnd) for the fundamental frequency (F0) of high-pass filtered and low-pass masked click trains was measured, with F0 (100 to 250 Hz) and the cut frequency (0.5 to 6 kHz) being varied orthogonally. The data confirm the result of Houtsma and Smurzynski [J. Acoust. Soc. Am. 87, 304-310 (1990)] that a pitch mechanism working on the temporal structure of the signal is responsible for analyzing frequencies higher than ten times the fundamental. Using high-pass filtered click trains, however, the jnd for the temporal analysis is at 1.2% as compared to 2%-3% found in studies using band-pass filtered stimuli. Two further experiments provide evidence that the pitch of this stimulus can convey musical information. A fourth experiment replicates the finding of Kaernbach and Demany on first- and second-order regularities with a cut frequency of 2 kHz and extends the paradigm to binaural aperiodic click sequences. The result suggests that listeners can detect first-order temporal regularities in monaural click streams as well as in binaurally fused click streams.

  16. Protein Machineries Involved in the Attachment of Heme to Cytochrome c: Protein Structures and Molecular Mechanisms

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    Carlo Travaglini-Allocatelli

    2013-01-01

    Full Text Available Cytochromes c (Cyt c are ubiquitous heme-containing proteins, mainly involved in electron transfer processes, whose structure and functions have been and still are intensely studied. Surprisingly, our understanding of the molecular mechanism whereby the heme group is covalently attached to the apoprotein (apoCyt in the cell is still largely unknown. This posttranslational process, known as Cyt c biogenesis or Cyt c maturation, ensures the stereospecific formation of the thioether bonds between the heme vinyl groups and the cysteine thiols of the apoCyt heme binding motif. To accomplish this task, prokaryotic and eukaryotic cells have evolved distinctive protein machineries composed of different proteins. In this review, the structural and functional properties of the main maturation apparatuses found in gram-negative and gram-positive bacteria and in the mitochondria of eukaryotic cells will be presented, dissecting the Cyt c maturation process into three functional steps: (i heme translocation and delivery, (ii apoCyt thioreductive pathway, and (iii apoCyt chaperoning and heme ligation. Moreover, current hypotheses and open questions about the molecular mechanisms of each of the three steps will be discussed, with special attention to System I, the maturation apparatus found in gram-negative bacteria.

  17. A host defense mechanism involving CFTR-mediated bicarbonate secretion in bacterial prostatitis.

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    Chen Xie

    Full Text Available BACKGROUND: Prostatitis is associated with a characteristic increase in prostatic fluid pH; however, the underlying mechanism and its physiological significance have not been elucidated. METHODOLOGY/PRINCIPAL FINDINGS: In this study a primary culture of rat prostatic epithelial cells and a rat prostatitis model were used. Here we reported the involvement of CFTR, a cAMP-activated anion channel conducting both Cl(- and HCO(3(-, in mediating prostate HCO(3(- secretion and its possible role in bacterial killing. Upon Escherichia coli (E. coli-LPS challenge, the expression of CFTR and carbonic anhydrase II (CA II, along with several pro-inflammatory cytokines was up-regulated in the primary culture of rat prostate epithelial cells. Inhibiting CFTR function in vitro or in vivo resulted in reduced bacterial killing by prostate epithelial cells or the prostate. High HCO(3(- content (>50 mM, rather than alkaline pH, was found to be responsible for bacterial killing. The direct action of HCO(3(- on bacterial killing was confirmed by its ability to increase cAMP production and suppress bacterial initiation factors in E. coli. The relevance of the CFTR-mediated HCO(3(- secretion in humans was demonstrated by the upregulated expression of CFTR and CAII in human prostatitis tissues. CONCLUSIONS/SIGNIFICANCE: The CFTR and its mediated HCO(3(- secretion may be up-regulated in prostatitis as a host defense mechanism.

  18. Mechanism of microglia neuroprotection: Involvement of P2X7, TNFα, and valproic acid.

    Science.gov (United States)

    Masuch, Annette; Shieh, Chu-Hsin; van Rooijen, Nico; van Calker, Dietrich; Biber, Knut

    2016-01-01

    Recently, we have demonstrated that ramified microglia are neuroprotective in N-methyl-D-aspartate (NMDA)-induced excitotoxicity in organotypic hippocampal slice cultures (OHSCs). The present study aimed to elucidate the underlying neuron-glia communication mechanism. It is shown here that pretreatment of OHSC with high concentrations of adenosine 5'-triphosphate (ATP) reduced NMDA-induced neuronal death only in presence of microglia. Specific agonists and antagonists identified the P2X7 receptor as neuroprotective receptor which was confirmed by absence of ATP-dependent neuroprotection in P2X7-deficient OHSC. Microglia replenished chimeric OHSC consisting of wild-type tissue replenished with P2X7-deficient microglia confirmed the involvement of microglial P2X7 receptor in neuroprotection. Stimulation of P2X7 in primary microglia induced tumor necrosis factor α (TNFα) release and blocking TNFα by a neutralizing antibody in OHSC abolished neuroprotection by ATP. OHSC from TNFα-deficient mice show increased exicitoxicity and activation of P2X7 did not rescue neuronal survival in the absence of TNFα. The neuroprotective effect of valproic acid (VPA) was strictly dependent on the presence of microglia and was mediated by upregulation of P2X7 in the cells. The present study demonstrates that microglia-mediated neuroprotection depends on ATP-activated purine receptor P2X7 and induction of TNFα release. This neuroprotective pathway was strengthened by VPA elucidating a novel mechanism for the neuroprotective function of VPA.

  19. Mechanism of oxidative stress involved in the toxicity of ZnO nanoparticles against eukaryotic cells

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    M. Saliani

    2016-01-01

    Full Text Available ZnO NPs (zinc oxide nanoparticles has generated significant scientific interest as a novel antibacterial and anticancer agent. Since oxidative stress is a critical determinant of ZnO NPs-induced damage, it is necessary to characterize their underlying mode of action. Different structural and physicochemical properties of ZnO NPs such as particle surface, size, shape, crystal structure, chemical position, and presence of metals can lead to changes in biological activities including ROS (reactive oxygen species production. However, there are some inconsistencies in the literature on the relation between the physicochemical features of ZnO NPs and their plausible oxidative stress mechanism. Herein, the possible oxidative stress mechanism of ZnO NPs was reviewed. This is worthy of further detailed evaluations in order to improve our understanding of vital NPs characteristics governing their toxicity. Therefore, this study focuses on the different reported oxidative stress paradigms induced by ZnO NPs including ROS generated by NPs, oxidative stress due to the NPs-cell interaction, and role of the particle dissolution in the oxidative damage. Also, this study tries to characterize and understand the multiple pathways involved in oxidative stress induced by ZnO NPs. Knowledge about different cellular signaling cascades stimulated by ZnO NPs lead to the better interpretation of the toxic influences induced by the cellular and acellular parameters. Regarding the potential benefits of toxic effects of ZnO NPs, in-depth evaluation of their toxicity mechanism and various effects of these nanoparticles would facilitate their implementation for biomedical applications.

  20. Analysis of regulatory network involved in mechanical induction of embryonic stem cell differentiation.

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    Xinan Zhang

    Full Text Available Embryonic stem cells are conventionally differentiated by modulating specific growth factors in the cell culture media. Recently the effect of cellular mechanical microenvironment in inducing phenotype specific differentiation has attracted considerable attention. We have shown the possibility of inducing endoderm differentiation by culturing the stem cells on fibrin substrates of specific stiffness. Here, we analyze the regulatory network involved in such mechanically induced endoderm differentiation under two different experimental configurations of 2-dimensional and 3-dimensional culture, respectively. Mouse embryonic stem cells are differentiated on an array of substrates of varying mechanical properties and analyzed for relevant endoderm markers. The experimental data set is further analyzed for identification of co-regulated transcription factors across different substrate conditions using the technique of bi-clustering. Overlapped bi-clusters are identified following an optimization formulation, which is solved using an evolutionary algorithm. While typically such analysis is performed at the mean value of expression data across experimental repeats, the variability of stem cell systems reduces the confidence on such analysis of mean data. Bootstrapping technique is thus integrated with the bi-clustering algorithm to determine sets of robust bi-clusters, which is found to differ significantly from corresponding bi-clusters at the mean data value. Analysis of robust bi-clusters reveals an overall similar network interaction as has been reported for chemically induced endoderm or endodermal organs but with differences in patterning between 2-dimensional and 3-dimensional culture. Such analysis sheds light on the pathway of stem cell differentiation indicating the prospect of the two culture configurations for further maturation.

  1. Chronic alcohol exposure inhibits biotin uptake by pancreatic acinar cells: possible involvement of epigenetic mechanisms.

    Science.gov (United States)

    Srinivasan, Padmanabhan; Kapadia, Rubina; Biswas, Arundhati; Said, Hamid M

    2014-11-01

    Chronic exposure to alcohol affects different physiological aspects of pancreatic acinar cells (PAC), but its effect on the uptake process of biotin is not known. We addressed this issue using mouse-derived pancreatic acinar 266-6 cells chronically exposed to alcohol and wild-type and transgenic mice (carrying the human SLC5A6 5'-promoter) fed alcohol chronically. First we established that biotin uptake by PAC is Na(+) dependent and carrier mediated and involves sodium-dependent multivitamin transporter (SMVT). Chronic exposure of 266-6 cells to alcohol led to a significant inhibition in biotin uptake, expression of SMVT protein, and mRNA as well as in the activity of the SLC5A6 promoter. Similarly, chronic alcohol feeding of wild-type and transgenic mice carrying the SLC5A6 promoter led to a significant inhibition in biotin uptake by PAC, as well as in the expression of SMVT protein and mRNA and the activity of the SLC5A6 promoters expressed in the transgenic mice. We also found that chronic alcohol feeding of mice is associated with a significant increase in the methylation status of CpG islands predicted to be in the mouse Slc5a6 promoters and a decrease in the level of expression of transcription factor KLF-4, which plays an important role in regulating SLC5A6 promoter activity. These results demonstrate, for the first time, that chronic alcohol exposure negatively impacts biotin uptake in PAC and that this effect is exerted (at least in part) at the level of transcription of the SLC5A6 gene and may involve epigenetic/molecular mechanisms.

  2. Mechanisms involved in calcium oxalate endocytosis by Madin-Darby canine kidney cells

    Directory of Open Access Journals (Sweden)

    A.H. Campos

    2000-01-01

    Full Text Available Calcium oxalate (CaOx crystals adhere to and are internalized by tubular renal cells and it seems that this interaction is related (positively or negatively to the appearance of urinary calculi. The present study analyzes a series of mechanisms possibly involved in CaOx uptake by Madin-Darby canine kidney (MDCK cells. CaOx crystals were added to MDCK cell cultures and endocytosis was evaluated by polarized light microscopy. This process was inhibited by an increase in intracellular calcium by means of ionomycin (100 nM; N = 6; 43.9% inhibition; P<0.001 or thapsigargin (1 µM; N = 6; 33.3% inhibition; P<0.005 administration, and via blockade of cytoskeleton assembly by the addition of colchicine (10 µM; N = 8; 46.1% inhibition; P<0.001 or cytochalasin B (10 µM; N = 8; 34.2% inhibition; P<0.001. Furthermore, CaOx uptake was reduced when the activity of protein kinase C was inhibited by staurosporine (10 nM; N = 6; 44% inhibition; P<0.01, or that of cyclo-oxygenase by indomethacin (3 µM; N = 12; 17.2% inhibition; P<0.05; however, the uptake was unaffected by modulation of potassium channel activity with glibenclamide (3 µM; N = 6, tetraethylammonium (1 mM; N = 6 or cromakalim (1 µM; N = 6. Taken together, these data indicate that the process of CaOx internalization by renal tubular cells is similar to the endocytosis reported for other systems. These findings may be relevant to cellular phenomena involved in early stages of the formation of renal stones.

  3. Multiple mechanisms involved in diabetes protection by lipopolysaccharide in non-obese diabetic mice

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jun [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Department of Pharmacology, College of Medicine, Wuhan University of Science and Technology, Wuhan (China); Cao, Hui [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Wang, Hongjie [Section of Neurobiology, Torrey Pines Institute for Molecular Studies, Port Saint Lucie, FL (United States); Yin, Guoxiao; Du, Jiao; Xia, Fei; Lu, Jingli [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Xiang, Ming, E-mail: xiangming@mails.tjmu.edu.cn [Department of Pharmacology, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China)

    2015-06-15

    Toll-like receptor 4 (TLR4) activation has been proposed to be important for islet cell inflammation and eventually β cell loss in the course of type 1 diabetes (T1D) development. However, according to the “hygiene hypothesis”, bacterial endotoxin lipopolysaccharide (LPS), an agonist on TLR4, inhibits T1D progression. Here we investigated possible mechanisms for the protective effect of LPS on T1D development in non-obese diabetic (NOD) mice. We found that LPS administration to NOD mice during the prediabetic state neither prevented nor reversed insulitis, but delayed the onset and decreased the incidence of diabetes, and that a multiple-injection protocol is more effective than a single LPS intervention. Further, LPS administration suppressed spleen T lymphocyte proliferation, increased the generation of CD4{sup +}CD25{sup +}Foxp3{sup +} regulatory T cells (Tregs), reduced the synthesis of strong Th1 proinflammatory cytokines, and downregulated TLR4 and its downstream MyD88-dependent signaling pathway. Most importantly, multiple injections of LPS induced a potential tolerogenic dendritic cell (DC) subset with low TLR4 expression without influencing the DC phenotype. Explanting DCs from repeated LPS-treated NOD mice into NOD/SCID diabetic mice conferred sustained protective effects against the progression of diabetes in the recipients. Overall, these results suggest that multiple mechanisms are involved in the protective effects of LPS against the development of diabetes in NOD diabetic mice. These include Treg induction, down-regulation of TLR4 and its downstream MyD88-dependent signaling pathway, and the emergence of a potential tolerogenic DC subset. - Highlights: • Administration of lipopolysaccharide (LPS) prevented type 1 diabetes in NOD mice. • Downregulating TLR4 level and MyD88-dependent pathway contributed to protection of LPS. • LPS administration also hampered DC maturation and promoted Treg differentiation.

  4. Endoplasmic reticulum quality control is involved in the mechanism of endoglin-mediated hereditary haemorrhagic telangiectasia.

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    Bassam R Ali

    Full Text Available Hereditary haemorrhagic telangiectasia (HHT is an autosomal dominant genetic condition affecting the vascular system and is characterised by epistaxis, arteriovenous malformations and mucocutaneous and gastrointestinal telangiectases. This disorder affects approximately 1 in 8,000 people worldwide. Significant morbidity is associated with this condition in affected individuals, and anaemia can be a consequence of repeated haemorrhages from telangiectasia in the gut and nose. In the majority of the cases reported, the condition is caused by mutations in either ACVRL1 or endoglin genes, which encode components of the TGF-beta signalling pathway. Numerous missense mutations in endoglin have been reported as causative defects for HHT but the exact underlying cellular mechanisms caused by these mutations have not been fully established despite data supporting a role for the endoplasmic reticulum (ER quality control machinery. For this reason, we examined the subcellular trafficking of twenty-five endoglin disease-causing missense mutations. The mutant proteins were expressed in HeLa and HEK293 cell lines, and their subcellular localizations were established by confocal fluorescence microscopy alongside the analysis of their N-glycosylation profiles. ER quality control was found to be responsible in eight (L32R, V49F, C53R, V125D, A160D, P165L, I271N and A308D out of eleven mutants located on the orphan extracellular domain in addition to two (C363Y and C382W out of thirteen mutants in the Zona Pellucida (ZP domain. In addition, a single intracellular domain missense mutant was examined and found to traffic predominantly to the plasma membrane. These findings support the notion of the involvement of the ER's quality control in the mechanism of a significant number, but not all, missense endoglin mutants found in HHT type 1 patients. Other mechanisms including loss of interactions with signalling partners as well as adverse effects on functional

  5. Gene expression modulation and the molecular mechanisms involved in Nelfinavir resistance in Leishmania donovani axenic amastigotes.

    Science.gov (United States)

    Kumar, Pranav; Lodge, Robert; Raymond, Frédéric; Ritt, Jean-François; Jalaguier, Pascal; Corbeil, Jacques; Ouellette, Marc; Tremblay, Michel J

    2013-08-01

    Drug resistance is a major public health challenge in leishmaniasis chemotherapy, particularly in the case of emerging Leishmania/HIV-1 co-infections. We have delineated the mechanism of cell death induced by the HIV-1 protease inhibitor, Nelfinavir, in the Leishmania parasite. In order to further study Nelfinavir-Leishmania interactions, we selected Nelfinavir-resistant axenic amastigotes in vitro and characterized them. RNA expression profiling analyses and comparative genomic hybridizations of closely related Leishmania species were used as a screening tool to compare Nelfinavir-resistant and -sensitive parasites in order to identify candidate genes involved in drug resistance. Microarray analyses of Nelfinavir-resistant and -sensitive Leishmania amastigotes suggest that parasites regulate mRNA levels either by modulating gene copy numbers through chromosome aneuploidy, or gene deletion/duplication by homologous recombination. Interestingly, supernumerary chromosomes 6 and 11 in the resistant parasites lead to upregulation of the ABC class of transporters. Transporter assays using radiolabelled Nelfinavir suggest a greater drug accumulation in the resistant parasites and in a time-dependent manner. Furthermore, high-resolution electron microscopy and measurements of intracellular polyphosphate levels showed an increased number of cytoplasmic vesicular compartments known as acidocalcisomes in Nelfinavir-resistant parasites. Together these results suggest that Nelfinavir is rapidly and dramatically sequestered in drug-induced intracellular vesicles.

  6. Molecular mechanisms involved in the pathogenesis of alphavirus-induced arthritis.

    Science.gov (United States)

    Assunção-Miranda, Iranaia; Cruz-Oliveira, Christine; Da Poian, Andrea T

    2013-01-01

    Arthritogenic alphaviruses, including Ross River virus (RRV), Chikungunya virus (CHIKV), Sindbis virus (SINV), Mayaro virus (MAYV), O'nyong-nyong virus (ONNV), and Barmah Forest virus (BFV), cause incapacitating and long lasting articular disease/myalgia. Outbreaks of viral arthritis and the global distribution of these diseases point to the emergence of arthritogenic alphaviruses as an important public health problem. This review discusses the molecular mechanisms involved in alphavirus-induced arthritis, exploring the recent data obtained with in vitro systems and in vivo studies using animal models and samples from patients. The factors associated to the extension and persistence of symptoms are highlighted, focusing on (a) virus replication in target cells, and tissues, including macrophages and muscle cells; (b) the inflammatory and immune responses with recruitment and activation of macrophage, NK cells and T lymphocytes to the lesion focus and the increase of inflammatory mediators levels; and (c) the persistence of virus or viral products in joint and muscle tissues. We also discuss the importance of the establishment of novel animal models to test new molecular targets and to develop more efficient and selective drugs to treat these diseases.

  7. Molecular Mechanisms Involved in the Pathogenesis of Alphavirus-Induced Arthritis

    Directory of Open Access Journals (Sweden)

    Iranaia Assunção-Miranda

    2013-01-01

    Full Text Available Arthritogenic alphaviruses, including Ross River virus (RRV, Chikungunya virus (CHIKV, Sindbis virus (SINV, Mayaro virus (MAYV, O'nyong-nyong virus (ONNV, and Barmah Forest virus (BFV, cause incapacitating and long lasting articular disease/myalgia. Outbreaks of viral arthritis and the global distribution of these diseases point to the emergence of arthritogenic alphaviruses as an important public health problem. This review discusses the molecular mechanisms involved in alphavirus-induced arthritis, exploring the recent data obtained with in vitro systems and in vivo studies using animal models and samples from patients. The factors associated to the extension and persistence of symptoms are highlighted, focusing on (a virus replication in target cells, and tissues, including macrophages and muscle cells; (b the inflammatory and immune responses with recruitment and activation of macrophage, NK cells and T lymphocytes to the lesion focus and the increase of inflammatory mediators levels; and (c the persistence of virus or viral products in joint and muscle tissues. We also discuss the importance of the establishment of novel animal models to test new molecular targets and to develop more efficient and selective drugs to treat these diseases.

  8. Noradrenergic mechanism involved in the nociceptive modulation of hippocampal CA3 region of normal rats.

    Science.gov (United States)

    Jin, Hua; Teng, Yueqiu; Zhang, Xuexin; Yang, Chunxiao; Xu, Manying; Yang, Lizhuang

    2014-06-27

    Norepinephrine (NE) is an important neurotransmitter in the brain, and regulates antinociception. However, the mechanism of action of NE on pain-related neurons in the hippocampal CA3 region is not clear. This study examines the effects of NE, phentolamine on the electrical activities of pain-excited neurons (PENs) and pain-inhibited neurons (PINs) in the hippocampal CA3 region of rats. Trains of electric impulses applied to the right sciatic nerve were used as noxious stimulation. The electrical activities of PENs or PINs in the hippocampal CA3 region were recorded by using a glass microelectrode. Our results revealed that, in the hippocampal CA3 region, the intra-CA3 region microinjection of NE decreased the pain-evoked discharged frequency and prolonged the discharged latency of PEN, and increased the pain-evoked discharged frequency and shortened discharged inhibitory duration (ID) of PIN, exhibiting the specific analgesic effect of NE. While intra-CA3 region microinjection of phentolamine produced the opposite response. It implies that phentolamine can block the effect of endogenous NE to cause the enhanced response of PEN and PIN to noxious stimulation. On the basis of above findings we can deduce that NE, phentolamine and alpha-adrenoceptor are involved in the modulation of nociceptive information transmission in the hippocampal CA3 region.

  9. Mechanisms involved in alleviation of intestinal inflammation by bifidobacterium breve soluble factors.

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    Elise Heuvelin

    Full Text Available OBJECTIVES: Soluble factors released by Bifidobacterium breve C50 (Bb alleviate the secretion of pro-inflammatory cytokines by immune cells, but their effect on intestinal epithelium remains elusive. To decipher the mechanisms accounting for the cross-talk between bacteria/soluble factors and intestinal epithelium, we measured the capacity of the bacteria, its conditioned medium (Bb-CM and other Gram(+ commensal bacteria to dampen inflammatory chemokine secretion. METHODS: TNFalpha-induced chemokine (CXCL8 secretion and alteration of NF-kappaB and AP-1 signalling pathways by Bb were studied by EMSA, confocal microscopy and western blotting. Anti-inflammatory capacity was also tested in vivo in a model of TNBS-induced colitis in mice. RESULTS: Bb and Bb-CM, but not other commensal bacteria, induced a time and dose-dependent inhibition of CXCL8 secretion by epithelial cells driven by both AP-1 and NF-kappaB transcription pathways and implying decreased phosphorylation of p38-MAPK and IkappaB-alpha molecules. In TNBS-induced colitis in mice, Bb-CM decreased the colitis score and inflammatory cytokine expression, an effect reproduced by dendritic cell conditioning with Bb-CM. CONCLUSIONS: Bb and secreted soluble factors contribute positively to intestinal homeostasis by attenuating chemokine production. The results indicate that Bb down regulate inflammation at the epithelial level by inhibiting phosphorylations involved in inflammatory processes and by protective conditioning of dendritic cells.

  10. Neural mechanisms involved in the oral representation of percussion music: an fMRI study.

    Science.gov (United States)

    Tsai, Chen-Gia; Chen, Chien-Chung; Chou, Tai-Li; Chen, Jyh-Horng

    2010-11-01

    Numerous music cultures use nonsense syllables to represent percussive sounds. Covert reciting of these syllable sequences along with percussion music aids active listeners in keeping track of music. Owing to the acoustic dissimilarity between the representative syllables and the referent percussive sounds, associative learning is necessary for the oral representation of percussion music. We used functional magnetic resonance imaging (fMRI) to explore the neural processes underlying oral rehearsals of music. There were four music conditions in the experiment: (1) passive listening to unlearned percussion music, (2) active listening to learned percussion music, (3) active listening to the syllable representation of (2), and (4) active listening to learned melodic music. Our results specified two neural substrates of the association mechanisms involved in the oral representation of percussion music. First, information integration of heard sounds and the auditory consequences of subvocal rehearsals may engage the right planum temporale during active listening to percussion music. Second, mapping heard sounds to articulatory and laryngeal gestures may engage the left middle premotor cortex.

  11. Orientation mechanisms and sensory organs involved in host location in a dipteran parasitoid larva.

    Science.gov (United States)

    Crespo, José E; Lazzari, Claudio R; Castelo, Marcela K

    2011-01-01

    The robber fly Mallophora ruficauda is one of the principal pests of apiculture in the Pampas region of Argentina. Larvae are solitary ectoparasitoids of third-instar scarab beetle larvae. Females of M. ruficauda do not lay eggs on or near the hosts, but on tall grasses. After hatching, larvae are dispersed by the wind and drop to the ground, where they dig and search for potential hosts. It is known that second-instar larvae of M. ruficauda exhibit active host-searching behaviour towards their preferred hosts, i.e., third-instar larvae of Cyclocephala signaticollis. Although host-location seems to be mediated by chemical cues, the mechanism of orientation and the sensory organs involved in host location remain unknown. We carried out behavioural experiments in the laboratory to address these questions. We also tested whether the orientation behaviour is exclusively based on the use of chemical cues. We found that larvae of M. ruficauda detect the chemicals with chemosensilla on the maxillary palps. Only one maxillary palp suffices for orientation, but their bilateral ablation abolishes orientation. Besides, an hexane extract of the host body was as attractive as a live host. Our results support that M. ruficauda larvae find their hosts underground by means of chemoklinotaxis.

  12. Superoxide anions and hydrogen peroxide induce hepatocyte death by different mechanisms : Involvement of JNK and ERK MAP kinases

    NARCIS (Netherlands)

    Conde de la Rosa, L; Schoemaker, MH; Vrenken, TE; Buist-Homan, M; Havinga, R; Jansen, PLM; Moshage, H

    2006-01-01

    Background/Aims: In liver diseases, reactive oxygen species (ROS) are involved in cell death and liver injury, but the mechanisms are not completely elucidated. To elucidate the mechanisms of hepatocyte cell death induced by the ROS superoxide anions and hydrogen peroxide, primary cultures of hepato

  13. Autocrine CCL19 blocks dendritic cell migration toward weak gradients of CCL21

    DEFF Research Database (Denmark)

    Hansen, Morten; Met, Özcan; Larsen, Niels Bent

    2016-01-01

    the effect of autocrine CCL19 on in vitro migration of human DCs toward CCL21. Results. Using human monocyte-derived DCs in a 3D chemotaxis assay, we are the first to demonstrate that CCL19 more potently induces directed migration of human DCs compared with CCL21. When comparing migration of type 1 DCs......Background aims. Maturation of dendritic cells (DCs) induces their homing from peripheral to lymphatic tissues guided by CCL21. However, in vitro matured human monocyte-derived DC cancer vaccines injected intradermally migrate poorly to lymph nodes (LNs). In vitro maturation protocols generate DCs...... and PGE2-DCs, migration of type 1 DCs was strikingly impaired compared with PGE2-DCs, but only toward low concentrations of CCL21. When type 1 DCs were cultured overnight in fresh culture medium (reducing autocrine CCL19 levels), a rescuing effect was observed on migration toward low concentrations of CCL...

  14. Exosomes mediate stromal mobilization of autocrine Wnt-PCP signaling in breast cancer cell migration.

    Science.gov (United States)

    Luga, Valbona; Zhang, Liang; Viloria-Petit, Alicia M; Ogunjimi, Abiodun A; Inanlou, Mohammad R; Chiu, Elaine; Buchanan, Marguerite; Hosein, Abdel Nasser; Basik, Mark; Wrana, Jeffrey L

    2012-12-21

    Stroma in the tumor microenvironment plays a critical role in cancer progression, but how it promotes metastasis is poorly understood. Exosomes are small vesicles secreted by many cell types and enable a potent mode of intercellular communication. Here, we report that fibroblast-secreted exosomes promote breast cancer cell (BCC) protrusive activity and motility via Wnt-planar cell polarity (PCP) signaling. We show that exosome-stimulated BCC protrusions display mutually exclusive localization of the core PCP complexes, Fzd-Dvl and Vangl-Pk. In orthotopic mouse models of breast cancer, coinjection of BCCs with fibroblasts dramatically enhances metastasis that is dependent on PCP signaling in BCCs and the exosome component, Cd81 in fibroblasts. Moreover, we demonstrate that trafficking in BCCs promotes tethering of autocrine Wnt11 to fibroblast-derived exosomes. This work reveals an intercellular communication pathway whereby fibroblast exosomes mobilize autocrine Wnt-PCP signaling to drive BCC invasive behavior.

  15. Mechanism involved in trichloroethylene-induced liver cancer: Importance to environmental cleanup. 1998 annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    Bull, R.J.; Thrall, B.D.; Sasser, L.B.; Miller, J.H.; Schultz, I.R.

    1998-06-01

    'The objective of this project is to develop critical data for changing risk-based clean-up standards for trichloroethylene (TCE). The project is organized around two interrelated tasks: Task 1 addresses the tumorigenic and dosimetry issues for the metabolites of TCE that produce liver cancer in mice, dichloroacetate (DCA) and trichloroacetate (TCA). Early work had suggested that TCA was primarily responsible for TCE-induced liver tumors, but several, more mechanistic observations suggest that DCA may play a prominent role. This task is aimed at determining the basis for the selection hypothesis and seeks to prove that this mode of action is responsible for TCE-induced tumors. This project will supply the basic dose-response data from which low-dose extrapolations would be made. Task 2 seeks specific evidence that TCA and DCA are capable of promoting the growth of spontaneously initiated cells from mouse liver, in vitro. The data provide the clearest evidence that both metabolites act by a mechanism of selection rather than mutation. These data are necessary to select between a linear (i.e. no threshold) and non-linear low-dose extrapolation model. As of May of 1998, this research has identified two plausible modes of action by which TCE produces liver tumors in mice. These modes of action do not require the compounds to be mutagenic. The bulk of the experimental evidence suggests that neither TCE nor the two hepatocarcinogenic metabolites of TCE are mutagenic. The results from the colony formation assay clearly establish that both of these metabolites cause colony growth from initiated cells that occur spontaneously in the liver of B 6 C 3 F 1 mice, although the phenotypes of the colonies differ in the same manner as tumors differ, in vivo. In the case of DCA, a second mechanism may occur at a lower dose involving the release of insulin. This observation is timely as it was recently reported that occupational exposures to trichloroethylene results in 2 to 4

  16. Corticotropin-releasing hormone: an autocrine hormone that promotes lipogenesis in human sebocytes.

    Science.gov (United States)

    Zouboulis, Christos C; Seltmann, Holger; Hiroi, Naoki; Chen, WenChieh; Young, Maggie; Oeff, Marina; Scherbaum, Werner A; Orfanos, Constantin E; McCann, Samuel M; Bornstein, Stefan R

    2002-05-14

    Sebaceous glands may be involved in a pathway conceptually similar to that of the hypothalamic-pituitary-adrenal (HPA) axis. Such a pathway has been described and may occur in human skin and lately in the sebaceous glands because they express neuropeptide receptors. Corticotropin-releasing hormone (CRH) is the most proximal element of the HPA axis, and it acts as central coordinator for neuroendocrine and behavioral responses to stress. To further examine the probability of an HPA equivalent pathway, we investigated the expression of CRH, CRH-binding protein (CRH-BP), and CRH receptors (CRH-R) in SZ95 sebocytes in vitro and their regulation by CRH and several other hormones. CRH, CRH-BP, CRH-R1, and CRH-R2 were detectable in SZ95 sebocytes at the mRNA and protein levels: CRH-R1 was the predominant type (CRH-R1/CRH-R2 = 2). CRH was biologically active on human sebocytes: it induced biphasic increase in synthesis of sebaceous lipids with a maximum stimulation at 10(-7) M and up-regulated mRNA levels of 3 beta- hydroxysteroid dehydrogenase/Delta(5-4) isomerase, although it did not affect cell viability, cell proliferation, or IL-1 beta-induced IL-8 release. CRH, dehydroepiandrosterone, and 17 beta-estradiol did not modulate CRH-R expression, whereas testosterone at 10(-7) M down-regulated CRH-R1 and CRH-R2 mRNA expression at 6 to 24 h, and growth hormone (GH) switched CRH-R1 mRNA expression to CRH-R2 at 24 h. Based on these findings, CRH may be an autocrine hormone for human sebocytes that exerts homeostatic lipogenic activity, whereas testosterone and growth hormone induce CRH negative feedback. The findings implicate CRH in the clinical development of acne, seborrhea, androgenetic alopecia, skin aging, xerosis, and other skin disorders associated with alterations in lipid formation of sebaceous origin.

  17. Autocrine growth regulation of human glomerular mesangial cells is primarily mediated by basic fibroblast growth factor.

    OpenAIRE

    Francki, A.; Uciechowski, P.; Floege, J; von der Ohe, J.; Resch, K.; Radeke, H. H.

    1995-01-01

    For various forms of human glomerulonephritis a close relationship between inflammatory injury and a local mesangial proliferative response has been described. Herein, we used primary cultures of human glomerular mesangial cells (HMCs) from five different donors to determine the autocrine growth-inducing capacity of their supernatants after stimulation with different cytokines and lipopolysaccharide (LPS) to determine whether this effect is due to basic fibroblast growth factor (bFGF). The ba...

  18. Autocrine extracellular purinergic signaling in epithelial cells derived from polycystic kidneys.

    Science.gov (United States)

    Schwiebert, Erik M; Wallace, Darren P; Braunstein, Gavin M; King, Sandi R; Peti-Peterdi, Janos; Hanaoka, Kazushige; Guggino, William B; Guay-Woodford, Lisa M; Bell, P Darwin; Sullivan, Lawrence P; Grantham, Jared J; Taylor, Amanda L

    2002-04-01

    ATP and its metabolites are potent autocrine agonists that act extracellularly within tissues to affect epithelial function. In polycystic kidneys, renal tubules become dilated and/or encapsulated as cysts, creating abnormal microenvironments for autocrine signaling. Previously, our laboratory has shown that high-nanomolar to micromolar quantities of ATP are released from cell monolayers in vitro and detectable in cyst fluids from microdissected human autosomal dominant polycystic kidney (ADPKD) cysts. Here, we show enhanced ATP release from autosomal recessive polycystic kidney (ARPKD) and ADPKD epithelial cell models. RT-PCR and immunoblotting for P2Y G protein-coupled receptors and P2X purinergic receptor channels show expression of mRNA and/or protein for multiple subtypes from both families. Assays of cytosolic Ca(2+) concentration and secretory Cl(-) transport show P2Y and P2X purinergic receptor-mediated stimulation of Cl(-) secretion via cytosolic Ca(2+)-dependent signaling. Therefore, we hypothesize that autocrine purinergic signaling may augment detrimentally cyst volume expansion in ADPKD or tubule dilation in ARPKD, accelerating disease progression.

  19. Study of the Genes and Mechanism Involved in the Radioadaptive Response

    Science.gov (United States)

    Dasgupta, Pushan R.

    2009-01-01

    The radioadaptive response is a phenomenon where exposure to a prior low dose of radiation reduces the level of damage induced by a subsequent high radiation dose. The molecular mechanism behind this is still not well understood. Learning more about the radioadaptive response is critical for long duration spaceflight since astronauts are exposed to low levels of cosmic radiation. The micronucleus assay was used to measure the level of damage caused by radiation. Although cells which were not washed with phosphate buffered saline (PBS) after a low priming dose of 5cGy did not show adaptation to the challenge dose, washing the cells with PBS and giving the cells fresh media after the low dose did allow radioadaptation to occur. This is consistent with the results of a previous publication by another research group. In the present study, genes involved in DNA damage signaling and the oxidative stress response were studied using RT PCR techniques in order to look at changes in expression level after the low dose with or without washing. Our preliminary results indicate that upregulation of oxidative stress response genes ANGPTL7, NCF2, TTN, and SRXN1 may be involved in the radioadaptive response. The low dose of radiation alone was found to activate the oxidative stress response genes GPR156 and MTL5, whereas, washing the cells alone caused relatively robust upregulation of the oxidative stress response genes DUSP1 and PTGS2. Washing after the priming dose showed some changes in the expression level of several DNA damage signaling genes. In addition, we studied whether washing the cells after the priming dose has an effect on the level of nitric oxide in both the media and cells, since nitric oxide levels are known to increase in the media of the cells after a high dose of radiation only if the cells were already exposed to a low priming dose. Based on this preliminary study, we propose that washing the cells after priming exposure actually eliminates some factor

  20. Molecular mechanisms involved in the hormonal prevention of aging in the rat.

    Science.gov (United States)

    Tresguerres, Jesús A F; Kireev, Roman; Tresguerres, Ana F; Borras, Consuelo; Vara, Elena; Ariznavarreta, Carmen

    2008-02-01

    Previous data from our group have provided support for the role of GH, melatonin and estrogens in the prevention of aging of several physiological parameters from bone, liver metabolism, vascular activity, the central nervous system (CNS), the immune system and the skin. In the present work data on the molecular mechanisms involved are presented. A total of 140 male and female rats have been submitted to different treatments over 10 weeks, between 22 and 24 months of age. Males have been treated with GH and melatonin. Females were divided in two groups: intact and castrated at 12 months of age. The first group was treated with GH and melatonin and the second with the two latter compounds and additionally with estradiol and Phytosoya. Aging was associated with a reduction in the number of neurons of the hylus of the dentate gyrus of the hippocampus and with a reduction of neurogenesis. GH treatment increased the number of neurons but did not increase neurogenesis thus suggesting a reduction of apoptosis. This was supported by the reduction in nucleosomes and the increase in Bcl2 observed in cerebral homogenates together with an increase in sirtuin2 and a reduction of caspases 9 and 3. Melatonin, estrogen and Phytosoya treatments increased neurogenesis but did not enhance the total number of neurons. Aging induced a significant increase in mitochondrial nitric oxide in the hepatocytes, together with a reduction in the mitochondrial fraction content in cytochrome C and an increase of this compound in the cytosolic fraction. Reductions of glutathione peroxidase and glutathione S-transferase were also detected, thus indicating oxidative stress and possibly apoptosis. Treatment for 2.5 months of old rats with GH and melatonin were able to significantly and favourably affect age-induced deteriorations, thus reducing oxidative damage. Keratinocytes obtained from old rats in primary culture showed an increase in lipoperoxides, caspases 8 and 3 as well as a reduction in Bcl2

  1. Mechanisms of Action Involved in Ozone Therapy: Is healing induced via a mild oxidative stress?

    Science.gov (United States)

    Sagai, Masaru; Bocci, Velio

    2011-12-20

    stress. Recently these concepts have become widely accepted. The versatility of ozone in treating vascular and degenerative diseases as well as skin lesions, hernial disc and primary root carious lesions in children is emphasized. Further researches able to elucidate whether the mechanisms of action of ozone therapy involve nuclear transcription factors, such as Nrf2, NFAT, AP-1, and HIF-1α are warranted.

  2. Physiological mechanisms involved in resistance to cotton verticillium wilt induced by AM fungi

    Institute of Scientific and Technical Information of China (English)

    LIU Bing-jiang; LIU Run-jin

    2004-01-01

    @@ It was proved that arbuscular mycorrhizal (AM) fungi played an important role in increasing plant resistance to soilborne pathogens, especially when plants were pre-inoculated with AM fungi.Mechanisms involved in this phenomenon are not yet well understood. On the basis of the former experiment results in our lab, effects of AM fungi on cotton Verticillium wilt and the mechanisms of increasing disease resisitance by the tested fungi were studied in pot culture under greenhouse conditions. Two cotton cutivars Litai 8 and 86-1 which are susceptible to Verticillium dahliae were pre-inoculated with Glomus fasiculatum, and Gigaspora margarita, then inoculated with the strain of Verticillium dahliae, namely "An-Yang" (belong to intermediate virulent type) 30 days after the former inoculation. Results showed that AM fungi could improve the growth and development of cotton plants, increase plants dry mass, decrease incidence and disease index of Verticillium wilt of cotton plants, inhibit the infection and development of V. dahliae to different extent in the rhizosphere of cotton pre-inoculated with AM fungi, while the colonization and spore numbers of AM fungi were not reduced significantly by this pathogen. The defence enzymes, such as phenylalanine ammonia-lyase (PAL), chitinase, β-1, 3-glucanase, peroxidase, polyphenoloxidase (PPO) were induced, and their activities and peak increased by AM fungi in roots and leaves, and the increasing speed and peak of the enzyme activity were higher in treatment with AM fungus preinoculation than the inoculation with only V. dahliae, which suggested that defense response was activated by AM fungi, and then made the cotton to react strongly and rapidly to the infection of V. dahliae. In addition, AM fungi decreased the content of malondiadehyde (MDA) in cotton roots and leaves,protected membrane system and alleviated the damage caused by the pathogen. The AM fungus,Glomus fasiculatum showed the superior effects of biological

  3. Mechanisms of Action Involved in Ozone Therapy: Is healing induced via a mild oxidative stress?

    Directory of Open Access Journals (Sweden)

    Sagai Masaru

    2011-12-01

    moderate oxidative stress. Recently these concepts have become widely accepted. The versatility of ozone in treating vascular and degenerative diseases as well as skin lesions, hernial disc and primary root carious lesions in children is emphasized. Further researches able to elucidate whether the mechanisms of action of ozone therapy involve nuclear transcription factors, such as Nrf2, NFAT, AP-1, and HIF-1α are warranted.

  4. Mechanisms involved in the selective transfer of long chain polyunsaturted fatty acids to the fetus

    Directory of Open Access Journals (Sweden)

    Alfonso eGil-Sánchez

    2011-09-01

    Full Text Available The concentration of long chain polyunsaturated fatty acid (LCPUFA in the fetal brain increases dramatically from the third trimester until 18 months of life. Several studies have shown an association between the percentage of maternal plasma docosahexaenoic acid (DHA during gestation and development of the cognitive functions in the neonate. Since only very low levels of LCPUFA are synthesized in the fetus and placenta, their primary source for the fetus is that of maternal origin. Both in vitro and human in vivo studies using labelled fatty acids have shown the preferential transfer of LCPUFA from the placenta to the fetus compared with other fatty acids, although the mechanisms involved are still uncertain. The placenta takes up circulating maternal non-esterified fatty acids (NEFA and fatty acids released mainly by maternal lipoprotein lipase and endothelial lipase. These NEFA may enter the cell by passive diffusion or by means of membrane carrier proteins. Once in the cytosol, NEFA bind to cytosolic fatty acid-binding proteins for transfer to the fetal circulation or can be oxidized within the trophoblasts and even re-esterified and stored in lipid droplets (LD. Although trophoblast cells are not specialized in lipid storage, LCPUFA may up-regulate peroxisome proliferator activated receptor-γ (PPARγ and hence the gene expression of fatty acid transport carriers, fatty acid acyl-CoA synthetases and adipophilin or other enzymes related with lipolysis, modifying their rate of placental transfer and metabolization. The placental transfer of LCPUFA during pregnancy seems to be a key factor in the neurological development of the fetus. Increased knowledge on the factors that modify placental transfer of fatty acids would contribute to our understanding of this complex process.

  5. The molecular mechanism underlying Roberts syndrome involves loss of ESCO2 acetyltransferase activity.

    Science.gov (United States)

    Gordillo, Miriam; Vega, Hugo; Trainer, Alison H; Hou, Fajian; Sakai, Norio; Luque, Ricardo; Kayserili, Hülya; Basaran, Seher; Skovby, Flemming; Hennekam, Raoul C M; Uzielli, Maria L Giovannucci; Schnur, Rhonda E; Manouvrier, Sylvie; Chang, Susan; Blair, Edward; Hurst, Jane A; Forzano, Francesca; Meins, Moritz; Simola, Kalle O J; Raas-Rothschild, Annick; Schultz, Roger A; McDaniel, Lisa D; Ozono, Keiichi; Inui, Koji; Zou, Hui; Jabs, Ethylin Wang

    2008-07-15

    Roberts syndrome/SC phocomelia (RBS) is an autosomal recessive disorder with growth retardation, craniofacial abnormalities and limb reduction. Cellular alterations in RBS include lack of cohesion at the heterochromatic regions around centromeres and the long arm of the Y chromosome, reduced growth capacity, and hypersensitivity to DNA damaging agents. RBS is caused by mutations in ESCO2, which encodes a protein belonging to the highly conserved Eco1/Ctf7 family of acetyltransferases that is involved in regulating sister chromatid cohesion. We identified 10 new mutations expanding the number to 26 known ESCO2 mutations. We observed that these mutations result in complete or partial loss of the acetyltransferase domain except for the only missense mutation that occurs in this domain (c.1615T>G, W539G). To investigate the mechanism underlying RBS, we analyzed ESCO2 mutations for their effect on enzymatic activity and cellular phenotype. We found that ESCO2 W539G results in loss of autoacetyltransferase activity. The cellular phenotype produced by this mutation causes cohesion defects, proliferation capacity reduction and mitomycin C sensitivity equivalent to those produced by frameshift and nonsense mutations associated with decreased levels of mRNA and absence of protein. We found decreased proliferation capacity in RBS cell lines associated with cell death, but not with increased cell cycle duration, which could be a factor in the development of phocomelia and cleft palate in RBS. In summary, we provide the first evidence that loss of acetyltransferase activity contributes to the pathogenesis of RBS, underscoring the essential role of the enzymatic activity of the Eco1p family of proteins.

  6. Pathophysiological mechanisms involved in non-alcoholicsteatohepatitis and novel potential therapeutic targets

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Non-alcoholic fatty liver disease (NAFLD) is a major healthcare problem and represents the hepatic expression ofthe metabolic syndrome. NAFLD is classified as nonalcoholicfatty liver (NAFL) or simple steatosis, and nonalcoholicsteatohepatitis (NASH). NASH is characterizedby the presence of steatosis and inflammation withor without fibrosis. The physiopathology of NAFL andNASH and their progression to cirrhosis involve severalparallel and interrelated mechanisms, such as, insulinresistance (IR), lipotoxicity, inflammation, oxidativestress, and recently the gut-liver axis interaction has beendescribed. Incretin-based therapies could play a role inthe treatment of NAFLD. Glucagon-like peptide-1 (GLP-1)is an intestinal mucosa-derived hormone which is secretedinto the bloodstream in response to nutrient ingestion;it favors glucose-stimulated insulin secretion, inhibitionof postprandial glucagon secretion and delayed gastricemptying. It also promotes weight loss and is involvedin lipid metabolism. Once secreted, GLP-1 is quicklydegraded by dipeptidyl peptidase-4 (DPP-4). Therefore,DPP-4 inhibitors are able to extend the activity of GLP-1.Currently, GLP-1 agonists and DPP-4 inhibitors representattractive options for the treatment of NAFLD andNASH. The modulation of lipid and glucose metabolismthrough nuclear receptors, such as the farsenoid Xreceptor, also constitutes an attractive therapeutic target.Obeticholic acid is a potent activator of the farnesoidX nuclear receptor and reduces liver fat content andfibrosis in animal models. Ursodeoxycholic acid (UDCA)is a hydrophilic bile acid with immunomodulatory, antiinflammatory,antiapoptotic, antioxidant and antifibroticproperties. UDCA can improve IR and modulatelipid metabolism through its interaction with nuclearreceptors such as, TGR5, farnesoid X receptor-a, orthe small heterodimeric partner. Finally, pharmacologicmodulation of the gut microbiota could have a role in thetherapy of NAFLD and

  7. Role of pigment epithelium-derived factor in the involution of hemangioma: Autocrine growth inhibition of hemangioma-derived endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyung-Jin [Department of Pharmacology, College of Medicine, Seoul National University, Seoul 110-799 (Korea, Republic of); Department of Biomedical Science, College of Medicine, Seoul National University, Seoul 110-799 (Korea, Republic of); Yun, Jang-Hyuk; Heo, Jong-Ik [Department of Pharmacology, College of Medicine, Seoul National University, Seoul 110-799 (Korea, Republic of); Lee, Eun Hui [Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Min, Hye Sook [Department of Pathology, Seoul National University Hospital, Seoul 110-744 (Korea, Republic of); Choi, Tae Hyun, E-mail: psthchoi@snu.ac.kr [Department of Plastic and Reconstructive Surgery, Seoul National University Children’s Hospital, Seoul 110-744 (Korea, Republic of); Department of Pediatric Plastic and Reconstructive Surgery, Seoul National University Children’s Hospital, Seoul 110-744 (Korea, Republic of); Cho, Chung-Hyun, E-mail: iamhyun@snu.ac.kr [Department of Pharmacology, College of Medicine, Seoul National University, Seoul 110-799 (Korea, Republic of); Department of Biomedical Science, College of Medicine, Seoul National University, Seoul 110-799 (Korea, Republic of); Ischemic/Hypoxic Disease Institute, College of Medicine, Seoul National University, Seoul 110-799 (Korea, Republic of); Cancer Research Institute, College of Medicine, Seoul National University, Seoul 110-799 (Korea, Republic of)

    2014-11-14

    Highlights: • PEDF was expressed and induced during the involuting phase of IH. • PEDF inhibited the cell growth of the involuting HemECs in an autocrine manner. • PEDF suppression restored the impaired cell growth of the involuting HemECs. - Abstract: Hemangioma is a benign tumor derived from abnormal blood vessel growth. Unlike other vascular tumor counterparts, a hemangioma is known to proliferate during its early stage but it is followed by a stage of involution where regression of the tumor occurs. The critical onset leading to the involution of hemangioma is currently not well understood. This study focused on the molecular identities of the involution of hemangioma. We demonstrated that a soluble factor released from the involuting phase of hemangioma-derived endothelial cells (HemECs) and identified pigment epithelium-derived factor (PEDF) as an anti-angiogenic factor that was associated with the growth inhibition of the involuting HemECs. The growth inhibition of the involuting HemECs was reversed by suppression of PEDF in the involuting HemECs. Furthermore, we found that PEDF was more up-regulated in the involuting phase of hemangioma tissues than in the proliferating or the involuted. Taken together, we propose that PEDF accelerates the involution of hemangioma by growth inhibition of HemECs in an autocrine manner. The regulatory mechanism of PEDF expression could be a potential therapeutic target to treat hemangiomas.

  8. Involvement of lignin and hormones in the response of woody poplar taproots to mechanical stress.

    Science.gov (United States)

    Trupiano, Dalila; Di Iorio, Antonino; Montagnoli, Antonio; Lasserre, Bruno; Rocco, Mariapina; Grosso, Alessandro; Scaloni, Andrea; Marra, Mauro; Chiatante, Donato; Scippa, Gabriella S

    2012-09-01

    Mechanical stress is a widespread condition caused by numerous environmental factors that severely affect plant stability. In response to mechanical stress, plants have evolved complex response pathways able to detect mechanical perturbations and inducing a suite of modifications in order to improve anchorage. The response of woody roots to mechanical stresses has been studied mainly at the morphological and biomechanical level, whereas investigations on the factors triggering these important alterations are still at the initial stage. Populus has been widely used to study the response of stem to different mechanical stresses and, since it has the first forest tree genome to be decoded, represents a model woody plant for addressing questions on the mechanisms controlling adaptation of woody roots to changing environments. In this study, a morphological and physiological analysis was used to investigate factors controlling modifications in Populus nigra woody taproots subjected to mechanical stress. An experimental model analyzing spatial and temporal mechanical force distribution along the woody taproot axis enabled us to compare the events occurring in its above-, central- and below-bending sectors. Different morphogenetic responses and local variations of lignin and plant hormones content have been observed, and a relation with the distribution of the mechanical forces along the stressed woody taproots is hypothesized. We investigated the differences of the response to mechanical stress induction during the time; in this regard, we present data referring to the effect of mechanical stress on plant transition from its condition of winter dormancy to that of full vegetative activity.

  9. Mechanisms involved in the psychological distress of Black Caribbeans in the United States

    Science.gov (United States)

    Govia, Ishtar O.

    The mental health of ethnic minorities in the United States is of urgent concern. The accelerated growth of groups of ethnic minorities and immigrants in the United States and the stressors to which they are exposed, implores academic researchers to investigate more deeply health disparities and the factors that exacerbate or minimize such inequalities. This dissertation attended to that concern. It used data from the National Survey of American Life (NSAL), the first survey with a national representative sample of Black Caribbeans, to explore mechanisms that involved in the psychological distress of Black Caribbeans in the United States. In a series of three studies, the dissertation investigated the role and consequence of (1) chronic discrimination, immigration factors, and closeness to ethnic and racial groups; (2) personal control and social support; and (3) family relations and social roles in the psychological distress of Black Caribbeans. Study 1 examined how the associations between discrimination and psychological distress were buffered or exacerbated by closeness to ethnic group and closeness to racial group. It also examined how these associations differed depending on immigration factors. Results indicated that the buffering or exacerbating effect of ethnic and racial group closeness varied according to the type of discrimination (subtle or severe) and were more pronounced among those born in the United States. Using the stress process framework, Study 2 tested moderation and mediation models of the effects of social support and personal control in the association between discrimination and distress. Results from a series of analyses on 579 respondents suggested that personal control served as a mediator in this relationship and that emotional support exerted a direct distress deterring function. Study 3 investigated sex differences in the associations between social roles, intergenerational family relationship perceptions and distress. Results

  10. Mangiferin, a natural xanthone, accelerates gastrointestinal transit in mice involving cholinergic mechanism

    Institute of Scientific and Technical Information of China (English)

    Talita Cavalcante Morais; Synara Cavalcante Lopes; Karine Maria Martins Bezerra Carvalho; Bruno Rodrigues Arruda; Francisco Thiago Correia de Souza; Maria Teresa Salles Trevisan; Vietla Satyanarayana Rao; Flávia Almeida Santos

    2012-01-01

    AIM:To investigate the effects of mangiferin on gastrointestinal transit (GIT) in normal and constipated mice,together with the possible mechanism.METHODS:Intragastrically-administered charcoal meal was used to measure GIT in overnight starved Swiss mice.In the first experiments,mangiferin (3 mg/kg,10mg/kg,30 mg/kg,and 100 mg/kg,po) or tegaserod (1mg/kg,ip) were administered 30 min before the charcoal meal to study their effects on normal transit.In the second series,mangiferin (30 mg/kg) was tested on delayed GIT induced by several different pharmacological agonists (morphine,clonidine,capsaicin) or antagonists (ondansetron,verapamil,and atropine) whereas in the third series,mangiferin (30 mg/kg,100mg/kg and 300 mg/kg) or tegaserod (1 mg/kg) were tested on 6 h fecal pellets outputted by freely fed mice.The ratio of wet to dry weight was calculated and used as a marker of fecal water content.RESULTS:Mangiferin administered orally significantly (P < 0.05) accelerated GIT at 30 mg/kg and 100 mg/kg (89%and 93%,respectively),similarly to 5-hydroxytryptamine4 (5-HT4) agonist tegaserod (81%) when compared to vehicle-treated control (63%).Co-administered mangiferin (30 mg/kg) totally reversed the inhibitory effect of opioid agonist morphine,5-HT3-receptor antagonist ondansetron and transient receptor potential vanilloid-1 receptor agonist capsaicin on GIT,but only to a partial extent with the GIT-delay induced by α2-adrenoceptor agonist clonidine,and calcium antagonist verapamil.However,co-administered atropine completely blocked the stimulant effect of mangiferin on GIT,suggesting the involvement of muscarinic acetylcholine receptor activation.Although mangiferin significantly enhanced the 6 h fecal output at higher doses (245.5 ± 10.43 mg vs 161.9 ± 10.82 mg and 227.1 ± 20.11 mg vs 161.9 ±10.82 mg of vehicle-treated control,at 30 and 100 mg/kg,P < 0.05,respectively),the effect of tegaserod was more potent (297.4 ± 7.42 mg vs 161.9 ± 10.82 mg of

  11. Mangiferin, a natural xanthone, accelerates gastrointestinal transit in mice involving cholinergic mechanism

    Science.gov (United States)

    Morais, Talita Cavalcante; Lopes, Synara Cavalcante; Carvalho, Karine Maria Martins Bezerra; Arruda, Bruno Rodrigues; de Souza, Francisco Thiago Correia; Trevisan, Maria Teresa Salles; Rao, Vietla Satyanarayana; Santos, Flávia Almeida

    2012-01-01

    AIM: To investigate the effects of mangiferin on gastrointestinal transit (GIT) in normal and constipated mice, together with the possible mechanism. METHODS: Intragastrically-administered charcoal meal was used to measure GIT in overnight starved Swiss mice. In the first experiments, mangiferin (3 mg/kg, 10 mg/kg, 30 mg/kg, and 100 mg/kg, po) or tegaserod (1 mg/kg, ip) were administered 30 min before the charcoal meal to study their effects on normal transit. In the second series, mangiferin (30 mg/kg) was tested on delayed GIT induced by several different pharmacological agonists (morphine, clonidine, capsaicin) or antagonists (ondansetron, verapamil, and atropine) whereas in the third series, mangiferin (30 mg/kg, 100 mg/kg and 300 mg/kg) or tegaserod (1 mg/kg) were tested on 6 h fecal pellets outputted by freely fed mice. The ratio of wet to dry weight was calculated and used as a marker of fecal water content. RESULTS: Mangiferin administered orally significantly (P < 0.05) accelerated GIT at 30 mg/kg and 100 mg/kg (89% and 93%, respectively), similarly to 5-hydroxytryptamine4 (5-HT4) agonist tegaserod (81%) when compared to vehicle-treated control (63%). Co-administered mangiferin (30 mg/kg) totally reversed the inhibitory effect of opioid agonist morphine, 5-HT3-receptor antagonist ondansetron and transient receptor potential vanilloid-1 receptor agonist capsaicin on GIT, but only to a partial extent with the GIT-delay induced by α2-adrenoceptor agonist clonidine, and calcium antagonist verapamil. However, co-administered atropine completely blocked the stimulant effect of mangiferin on GIT, suggesting the involvement of muscarinic acetylcholine receptor activation. Although mangiferin significantly enhanced the 6 h fecal output at higher doses (245.5 ± 10.43 mg vs 161.9 ± 10.82 mg and 227.1 ± 20.11 mg vs 161.9 ± 10.82 mg of vehicle-treated control, at 30 and 100 mg/kg, P < 0.05, respectively), the effect of tegaserod was more potent (297.4 ± 7.42 mg

  12. A novel mechanism of hippocampal LTD involving muscarinic receptor-triggered interactions between AMPARs, GRIP and liprin-α

    Directory of Open Access Journals (Sweden)

    Dickinson Bryony A

    2009-06-01

    Full Text Available Abstract Background Long-term depression (LTD in the hippocampus can be induced by activation of different types of G-protein coupled receptors, in particular metabotropic glutamate receptors (mGluRs and muscarinic acethycholine receptors (mAChRs. Since mGluRs and mAChRs activate the same G-proteins and isoforms of phospholipase C (PLC, it would be expected that these two forms of LTD utilise the same molecular mechanisms. However, we find a distinct mechanism of LTD involving GRIP and liprin-α. Results Whilst both forms of LTD require activation of tyrosine phosphatases and involve internalisation of AMPARs, they use different molecular interactions. Specifically, mAChR-LTD, but not mGluR-LTD, is blocked by peptides that inhibit the binding of GRIP to the AMPA receptor subunit GluA2 and the binding of GRIP to liprin-α. Thus, different receptors that utilise the same G-proteins can regulate AMPAR trafficking and synaptic efficacy via distinct molecular mechanisms. Conclusion Our results suggest that mAChR-LTD selectively involves interactions between GRIP and liprin-α. These data indicate a novel mechanism of synaptic plasticity in which activation of M1 receptors results in AMPAR endocytosis, via a mechanism involving interactions between GluA2, GRIP and liprin-α.

  13. Neurotensin (NTS) and its receptor (NTSR1) causes EGFR, HER2 and HER3 over-expression and their autocrine/paracrine activation in lung tumors, confirming responsiveness to erlotinib.

    Science.gov (United States)

    Younes, Mohamad; Wu, Zherui; Dupouy, Sandra; Lupo, Audrey Mansuet; Mourra, Najat; Takahashi, Takashi; Fléjou, Jean François; Trédaniel, Jean; Régnard, Jean François; Damotte, Diane; Alifano, Marco; Forgez, Patricia

    2014-09-30

    Alterations in the signaling pathways of epidermal growth factor receptors (HERs) are associated with tumor aggressiveness. Neurotensin (NTS) and its high affinity receptor (NTSR1) are up regulated in 60% of lung cancers. In a previous clinical study, NTSR1 overexpression was shown to predict a poor prognosis for 5 year overall survival in a selected population of stage I lung adenocarcinomas treated by surgery alone. In a second study, shown here, the frequent and high expression of NTSR1 was correlated with a pejorative prognosis in 389 patients with stage I to III lung adenocarcinoma, and was an independent prognosis marker. Interactions between NTS and NTSR1 induce pro-oncogenic biological effects associated with neoplastic processes and tumor progression. Here we highlight the cellular mechanisms activated by Neurotensin (NTS) and its high affinity receptor (NTSR1) contributing to lung cancer cell aggressiveness. We show that the NTS autocrine and/or paracrine regulation causes EGFR, HER2, and HER3 over-expression and activation in lung tumor cells. The EGFR and HER3 autocrine activation is mediated by MMP1 activation and EGF "like" ligands (HB-EGF, Neuregulin 1) release. By establishing autocrine and/or paracrine NTS regulation, we show that tumor growth is modulated according to NTS expression, with a low growth rate in those tumors that do not express NTS. Accordingly, xenografted tumors expressing NTS and NTSR1 showed a positive response to erlotinib, whereas tumors void of NTSR1 expression had no detectable response. This is consistent with the presence of a NTS autocrine loop, leading to the sustained activation of EGFR and responsible for cancer aggressiveness. We propose the use of NTS/NTSR1 tumor expression, as a biomarker for the use of EGFR tyrosine kinase inhibitors in patients lacking EGFR mutation.

  14. Role of TGF-β in Survival of Phagocytizing Microglia: Autocrine Suppression of TNF-α Production and Oxidative Stress.

    Science.gov (United States)

    Ryu, Keun-Young; Cho, Geum-Sil; Piao, Hua Zi; Kim, Won-Ki

    2012-12-01

    Microglia are recognized as residential macrophageal cells in the brain. Activated microglia play a critical role in removal of dead or damaged cells through phagocytosis activity. During phagocytosis, however, microglia should survive under the harmful condition of self-producing ROS and pro-inflammatory mediators. TGF-β has been known as a classic anti-inflammatory cytokine and controls both initiation and resolution of inflammation by counter-acting inflammatory cytokines. In the present study, to understand the self-protective mechanism, we studied time-dependent change of TNF-α and TGF-β production in microglia phagocytizing opsonized-beads (i.e., polystyrene microspheres). We found that microglia phagocytized opsonized-bead in a time-dependent manner and simultaneously produced both TNF-α and TGF-β. However, while TNF-α production gradually decreased after 6 h, TGF-β production remained at increased level. Microglial cells pre-treated with lipopolysaccharides (a strong immunostimulant, LPS) synergistically increased the production of TNF-α and TGF-β both. However, LPS-pretreated microglia produced TNF-α in a more sustained manner and became more vulnerable, probably due to the marked and sustained production of TNF-α and reduced TGF-β. Intracellular oxidative stress appears to change in parallel with the microglial production of TNF-α. These results indicate TGF-β contributes for the survival of phagocytizing microglia through autocrine suppression of TNF-α production and oxidative stress.

  15. MECHANISMS INVOLVED IN TRICHLOROETHYLENE INDUCED LIVER CANCER: IMPORTANCE TO ENVIRONMENTAL CLEANUP

    Energy Technology Data Exchange (ETDEWEB)

    Bull, Richard J.; Thrall, Brain D.

    2001-12-31

    Trichloroethylene (TCE) is a common contaminant of groundwater as a result of poor disposal practices of the past. As a consequence, this solvent is the focus of many clean-up operations of uncontrolled hazardous waste sites. TCE is carcinogenic in both mice and rats, but at different sites, the liver and kidney, respectively (NCI 1976; NTP 1988; NTP 1990). Liver tumor induction in mice has been the tumor most critical from the standpoint of environmental regulation (Bull 2000). Under the proposed cancer risk guidelines of the Environmental Protection Agency (EPA 1996), identifying the dose-response behavior of key events involved in carcinogenic responses can be used for developing alternative risk assessments. A major difficulty in developing alternative approaches for TCE is the fact that three of its metabolites are capable of inducing liver cancer in mice (Bull et al. 1990; Daniel et al. 1992; DeAngelo et al. 1999; Pereria 1996). Two of these metabolites have distinct modes of action, dichloroacetate (DCA) and trichloroacetate (TCA). The third metabolite, chloral hydrate, is probably active as a result of its conversion to one or both of these two metabolites. Ordinarily, the first approach to assigning causality to a metabolite in tumorigenesis would be an attempt to measure its concentration in the body and associate that with tumorigenic concentrations observed when the compound is itself administered. This can be done with relative ease with TCA. However, it has been more difficult with DCA since blood levels of this metabolite after exposure to carcinogenic doses of DCA fall rapidly below detection limits (Kato-Weinstein et al. 1998; Merdink et al. 1998). Mutations in the ras protooncogene have been used to determine if distinct patterns of DNAsequence alterations can provide indications of the type of DNA damage that might be produced by carcinogens. The presence of ras mutations in chemically-induced tumors was suggested as a means o f determining

  16. Swarming mechanisms in the yellow fever mosquito: aggregation pheromones involved in the mating behavior of Aedes aegypti

    Science.gov (United States)

    Mosquitoes of various species mate in swarms comprised of tens to thousands flying males. Yet little information is known about mosquito swarming mechanism. Discovering chemical cues involved in mosquito biology leads to better adaptation of disease control interventions. In this study, we aimed ...

  17. Study of the Chemical Mechanism Involved in the Formation of Tungstite in Benzyl Alcohol by the Advanced QEXAFS Technique

    DEFF Research Database (Denmark)

    Olliges‐Stadler, Inga; Stötzel, Jan; Koziej, Dorota

    2012-01-01

    Insight into the complex chemical mechanism for the formation of tungstite nanoparticles obtained by the reaction of tungsten hexachloride with benzyl alcohol is presented herein. The organic and inorganic species involved in the formation of the nanoparticles were studied by time‐dependent gas c...

  18. Identification and Characterization of the Phage Gene sav, Involved in Sensitivity to the Lactococcal Abortive Infection Mechanism AbiV

    DEFF Research Database (Denmark)

    Haaber, Jakob Brandt Borup; Rousseau, G. M.; Hammer, Karin;

    2009-01-01

    Lactococcus lactis phage mutants that are insensitive to the recently characterized abortive infection mechanism AbiV were isolated and analyzed in an effort to elucidate factors involved in the sensitivity to AbiV. Whole-genome sequencing of the phage mutants p2.1 and p2.2 revealed mutations...

  19. SF/HGF-c-Met autocrine and paracrine promote metastasis of hepatocellular carcinoma

    Institute of Scientific and Technical Information of China (English)

    Qian Xie; Kang-Da Liu; Mei-Yu Hu; Kang Zhou

    2001-01-01

    AIM: To explore the role of SF/HGF-Met autocrine and parscrine in metastasis of hepatocellular carcinoma (HCC). METHODS: SF/HGF and c-met transcription and protein expression in HCC were examined by RT-PCR and Western Blot in 4 HCC cell lines, including HepG2, Hep3B,SMMC7721 and MHCC-1, the last cell line had a higher potential of metastasis. Sf/hgf cDNA was transfected by the method of Lipofectin into SMMC7721. SF/HGF and c-met antibody were used to stimulate and block SF/HGF-c-met signal transduction. Cell morphology, mobility, and proliferation were respectively compared by microscopic observation, wound healing assay and cell growth curve. RESULTS: HCC malignancy appeared to be relative to its met-SF/HGF expression. In MHCC-1, c-met expression was much stronger than that in other cell lines with lower potential of metastasis and only SF/HGF autocrine existed in MHCC-1. After sf/hgf cDNA transfection or conditioned medium of MHCC-1 stimulation, SMMC7721 changed into elongated morphology, and the abilities of proliferation ( P < 0.05) and mobility increased. Such bio-activity could he blocked by c-met antibody ( P< 0.05). CONCLUSION: The system of SF/HGF-c-met autocrine and paracrine played an important role in development and metastasis potential of HCC. Inhibition of SF/HGF-c-met signal transduction system may reduce the growth and metastasis of HCC.

  20. Molecular mechanism for the involvement of nuclear receptor FXR in HBV-associated hepatocellular carcinoma

    Directory of Open Access Journals (Sweden)

    Yong-dong Niu

    2011-08-01

    Full Text Available Farnesoid X receptor (FXR, also termed nuclear receptor NR1H4 is critically involved in the regulation of nascent bile formation and bile acid enterohepatic circulation. FXR and bile acids have been shown to play roles in liver regeneration and inflammatory responses. There is increasing evidence suggesting that FXR and the FXR signaling pathway are involved in the pathophysiology of a wide range of liver diseases, such as viral hepatitis, cirrhosis, and hepatocellular carcinoma (HCC. Here we discuss the latest discoveries of FXR functions with relevance to bile acid metabolism and HBV-associated HCC. More specifically, the goal of this review is to discuss the roles of FXR and bile acids in regulating HBV replication and how disregulation of the FXR-bile acid signaling pathway is involved in HBV-associated hepatocarcinogenesis.

  1. A Mechanism for Land-Atmosphere Feedback Involving Planetary Wave Structures

    Science.gov (United States)

    Koster, Randal D.; Chang, Yehui; Schubert, Siegfried D.

    2014-01-01

    While the ability of land surface conditions to influence the atmosphere has been demonstrated in various modeling and observational studies, the precise mechanisms by which land-atmosphere feedback occurs are still largely unknown particularly the mechanisms that allow land moisture state in one region to affect atmospheric conditions in another. Such remote impacts are examined here in the context of atmospheric general circulation model (AGCM) simulations, leading to the identification of one potential mechanism: the phase-locking and amplification of a planetary wave through the imposition of a spatial pattern of soil moisture at the land surface. This mechanism, shown here to be relevant in the AGCM, apparently also operates in nature, as suggested by supporting evidence found in reanalysis data.

  2. Sensitizing Children to the Social and Emotional Mechanisms Involved in Racism: A Program Evaluation

    Science.gov (United States)

    Triliva, Sofia; Anagnostopoulou, Tanya; Vleioras, Georgios

    2014-01-01

    This paper describes and discusses the results of an intervention aiming to sensitize children to the social and emotional processes involved in racism. The intervention was applied and evaluated in 10 Greek elementary schools. The goals and the intervention methods of the program modules are briefly outlined and the results of the program…

  3. Cumulative asbestos exposure for US automobile mechanics involved in brake repair (circa 1950s-2000).

    Science.gov (United States)

    Finley, Brent L; Richter, Richard O; Mowat, Fionna S; Mlynarek, Steve; Paustenbach, Dennis J; Warmerdam, John M; Sheehan, Patrick J

    2007-11-01

    We analyzed cumulative lifetime exposure to chrysotile asbestos experienced by brake mechanics in the US during the period 1950-2000. Using Monte Carlo methods, cumulative exposures were calculated using the distribution of 8-h time-weighted average exposure concentrations for brake mechanics and the distribution of job tenure data for automobile mechanics. The median estimated cumulative exposures for these mechanics, as predicted by three probabilistic models, ranged from 0.16 to 0.41 fibers per cubic centimeter (f/cm(3)) year for facilities with no dust-control procedures (1970s), and from 0.010 to 0.012 f/cm(3) year for those employing engineering controls (1980s). Upper-bound (95%) estimates for the 1970s and 1980s were 1.96 to 2.79 and 0.07-0.10 f/cm(3) year, respectively. These estimates for US brake mechanics are consistent with, but generally slightly lower than, those reported for European mechanics. The values are all substantially lower than the cumulative exposure of 4.5 f/cm(3) year associated with occupational exposure to 0.1 f/cm(3) of asbestos for 45 years that is currently permitted under the current occupational exposure limits in the US. Cumulative exposures were usually about 100- to 1,000-fold less than those of other occupational groups with asbestos exposure for similar time periods. The cumulative lifetime exposure estimates presented here, combined with the negative epidemiology data for brake mechanics, could be used to refine the risk assessments for chrysotile-exposed populations.

  4. The Role and Mechanisms of Action of Glucocorticoid Involvement in Memory Storage

    Directory of Open Access Journals (Sweden)

    Carmen Sandi

    1998-01-01

    integral aspect of the neurobiological mechanism underlying memory formation. By reviewing the work carried out in different learning models in chicks (passive avoidance learning and rats (spatial orientation in the Morris water maze and contextual fear conditioning, a role for brain corticosterone action through the glucocorticoid receptor type on the mechanisms of memory consolidation is hypothesized. Evidence is also presented to relate post-training corticosterone levels to the strength of memory storage. Finally, the possible molecular mechanisms that might mediate the influences of glucocorticoids in synaptic plasticity subserving long-term memory formation are considered, mainly by focusing on studies implicating a steroid action through (i glutamatergic transmission and (ii cell adhesion molecules.

  5. Estrogenic endocrine disruptors: Molecular mechanisms of action.

    Science.gov (United States)

    Kiyama, Ryoiti; Wada-Kiyama, Yuko

    2015-10-01

    A comprehensive summary of more than 450 estrogenic chemicals including estrogenic endocrine disruptors is provided here to understand the complex and profound impact of estrogen action. First, estrogenic chemicals are categorized by structure as well as their applications, usage and effects. Second, estrogenic signaling is examined by the molecular mechanism based on the receptors, signaling pathways, crosstalk/bypassing and autocrine/paracrine/homeostatic networks involved in the signaling. Third, evaluation of estrogen action is discussed by focusing on the technologies and protocols of the assays for assessing estrogenicity. Understanding the molecular mechanisms of estrogen action is important to assess the action of endocrine disruptors and will be used for risk management based on pathway-based toxicity testing.

  6. Constitutional Chromothripsis Rearrangements Involve Clustered Double-Stranded DNA Breaks and Nonhomologous Repair Mechanisms

    Directory of Open Access Journals (Sweden)

    Wigard P. Kloosterman

    2012-06-01

    Full Text Available Chromothripsis represents a novel phenomenon in the structural variation landscape of cancer genomes. Here, we analyze the genomes of ten patients with congenital disease who were preselected to carry complex chromosomal rearrangements with more than two breakpoints. The rearrangements displayed unanticipated complexity resembling chromothripsis. We find that eight of them contain hallmarks of multiple clustered double-stranded DNA breaks (DSBs on one or more chromosomes. In addition, nucleotide resolution analysis of 98 breakpoint junctions indicates that break repair involves nonhomologous or microhomology-mediated end joining. We observed that these eight rearrangements are balanced or contain sporadic deletions ranging in size between a few hundred base pairs and several megabases. The two remaining complex rearrangements did not display signs of DSBs and contain duplications, indicative of rearrangement processes involving template switching. Our work provides detailed insight into the characteristics of chromothripsis and supports a role for clustered DSBs driving some constitutional chromothripsis rearrangements.

  7. Cell wall trapping of autocrine peptides for human G-protein-coupled receptors on the yeast cell surface.

    Directory of Open Access Journals (Sweden)

    Jun Ishii

    Full Text Available G-protein-coupled receptors (GPCRs regulate a wide variety of physiological processes and are important pharmaceutical targets for drug discovery. Here, we describe a unique concept based on yeast cell-surface display technology to selectively track eligible peptides with agonistic activity for human GPCRs (Cell Wall Trapping of Autocrine Peptides (CWTrAP strategy. In our strategy, individual recombinant yeast cells are able to report autocrine-positive activity for human GPCRs by expressing a candidate peptide fused to an anchoring motif. Following expression and activation, yeast cells trap autocrine peptides onto their cell walls. Because captured peptides are incapable of diffusion, they have no impact on surrounding yeast cells that express the target human GPCR and non-signaling peptides. Therefore, individual yeast cells can assemble the autonomous signaling complex and allow single-cell screening of a yeast population. Our strategy may be applied to identify eligible peptides with agonistic activity for target human GPCRs.

  8. Study of the effects of dietary polyunsaturated fatty acids: Molecular mechanisms involved in intestinal inflammation

    OpenAIRE

    Knoch, Bianca; Matthew P.G. Barnett; McNabb, Warren C.; Roy, Nicole C.

    2009-01-01

    The use of «omic» techniques in combination with model systems and molecular tools allows to understand how foods and food components act on metabolic pathways to regulate transcriptional processes. Polyunsaturated fatty acids have distinctive nutritional and metabolic effects because they give rise to lipid mediated products and affect the expression of various genes involved in intestinal inflammation. The present review focuses on the molecular effects of dietary polyunsaturated fatty acid...

  9. A case of primary spinal myoclonus: clinical presentation and possible mechanisms involved

    OpenAIRE

    Campos Cynthia Resende; Limongi João Carlos Papaterra; Machado Flávia Costa Nunes; Brotto Mário Wilson Iervolino

    2003-01-01

    Spinal myoclonus is a rare movement disorder characterized by myoclonic involvement of a group of muscles supplied by a few contiguous segments of the spinal cord. Structural lesions are usually the cause, but in primary spinal myoclonus the etiology remains unknown. We present the case of a 26-year-old woman with cervical spinal myoclonus in which both clinical and electromyographic findings pointed to the segment C1-C3 as the origin of the myoclonus. Laboratorial examinations were normal an...

  10. VIGS for dissecting mechanisms involved in the symbiotic interaction of microbes with plants

    DEFF Research Database (Denmark)

    Grønlund, Mette

    2015-01-01

    Virus-induced gene silencing (VIGS) is an alternative reverse genetics tool for silencing of genes in some plants which are difficult to transform. The pea early browning virus (PEBV) has been developed as a VIGS vector and used in pea for functional analysis of several genes. Here, a PEBV-VIGS p......-VIGS protocol is described which is suitable for reverse genetics studies in pea for genes involved in the symbiosis with arbuscular mycorrhizal fungi and Rhizobium....

  11. Mechanism of Microglia Neuroprotection : Involvement of P2X7, TNF alpha, and Valproic Acid

    NARCIS (Netherlands)

    Masuch, Annette; Shieh, Chu-Hsin; van Rooijen, Nico; van Calker, Dietrich; Biber, Knut

    2016-01-01

    Recently, we have demonstrated that ramified microglia are neuroprotective in N-methyl-D-aspartate (NMDA)-induced excitotoxicity in organotypic hippocampal slice cultures (OHSCs). The present study aimed to elucidate the underlying neuron-glia communication mechanism. It is shown here that pretreatm

  12. An angiopoietin-like protein 2 autocrine signaling promotes EMT during pancreatic ductal carcinogenesis

    Science.gov (United States)

    Carbone, Carmine; Piro, Geny; Fassan, Matteo; Tamburrino, Anna; Mina, Maria Mihaela; Zanotto, Marco; Chiao, Paul J; Bassi, Claudio; Scarpa, Aldo; Tortora, Giampaolo; Melisi, Davide

    2015-01-01

    The identification of the earliest molecular events responsible for the metastatic dissemination of pancreatic ductal adenocarcinoma (PDAC) remains critical for early detection, prevention, and treatment interventions. In this study, we hypothesized that an autocrine signaling between Angiopoietin-like Protein (ANGPTL)2 and its receptor leukocyte immunoglobulin-like receptor B2 (LILRB2) might be responsible for the epithelial-to-mesenchymal transition (EMT) and, the early metastatic behavior of cells in pancreatic preneoplastic lesions. We demonstrated that the sequential activation of KRAS, expression of HER2 and silencing of p16/p14 are sufficient to progressively and significantly increase the secretion of ANGPTL2, and the expression of LILRB2. Silencing the expression of ANGPTL2 reverted EMT and reduced migration in these cell lines. Blocking ANGPTL2 receptor LILRB2 in KRAS, and KRAS/HER2/p16p14shRNA LILRB2- expressing cells reduced ANGPTL2-induced cell proliferation and invasion. An increasingly significant overexpression of ANGPTL2 was observed in in a series of 68 different human PanIN and 27 PDAC lesions if compared with normal pancreatic parenchyma. These findings showed that the autocrine signaling of ANGPTL2 and its receptor LILRB2 plays key roles in sustaining EMT and the early metastatic behavior of cells in pancreatic preneoplastic lesions supporting the potential role of ANGPTL2 for early detection, metastasis prevention, and treatment in PDAC. PMID:25360865

  13. IL-17C regulates the innate immune function of epithelial cells in an autocrine manner.

    Science.gov (United States)

    Ramirez-Carrozzi, Vladimir; Sambandam, Arivazhagan; Luis, Elizabeth; Lin, Zhongua; Jeet, Surinder; Lesch, Justin; Hackney, Jason; Kim, Janice; Zhou, Meijuan; Lai, Joyce; Modrusan, Zora; Sai, Tao; Lee, Wyne; Xu, Min; Caplazi, Patrick; Diehl, Lauri; de Voss, Jason; Balazs, Mercedesz; Gonzalez, Lino; Singh, Harinder; Ouyang, Wenjun; Pappu, Rajita

    2011-10-12

    Interleukin 17C (IL-17C) is a member of the IL-17 family that is selectively induced in epithelia by bacterial challenge and inflammatory stimuli. Here we show that IL-17C functioned in a unique autocrine manner, binding to a receptor complex consisting of the receptors IL-17RA and IL-17RE, which was preferentially expressed on tissue epithelial cells. IL-17C stimulated epithelial inflammatory responses, including the expression of proinflammatory cytokines, chemokines and antimicrobial peptides, which were similar to those induced by IL-17A and IL-17F. However, IL-17C was produced by distinct cellular sources, such as epithelial cells, in contrast to IL-17A, which was produced mainly by leukocytes, especially those of the T(H)17 subset of helper T cells. Whereas IL-17C promoted inflammation in an imiquimod-induced skin-inflammation model, it exerted protective functions in dextran sodium sulfate-induced colitis. Thus, IL-17C is an essential autocrine cytokine that regulates innate epithelial immune responses.

  14. Are immunological mechanisms involved in colon cancer and are they possible markers for biotherapy improvement?

    Science.gov (United States)

    Berghella, Anna Maria; Contasta, Ida; Pellegrini, Patrizia; Del Beato, Tiziana; Adorno, Domenico

    2006-10-01

    This paper focuses on our data on colon cancer patients. Our overall results lead us to believe that the suppressive effect of specific cytokines in colon cancer patients alters the functionality of TH1 and TH2 subsets of CD4+ T-cells, with an expansion of TH2 cells and a malfunctioning of TH1 cells. This immunological disregulation appears to increase with stage progression, suggesting a direct role in the mechanisms that allow the tumour to locate and expand within the host. It is also clear that in order to identify disease markers and generate an in vivo immune response that corrects the imbalance between TH1 and TH2 cells, we need to understand how tumour mechanisms cause this imbalance to begin with.

  15. Molecular mechanisms involved in the bidirectional relationship between diabetes mellitus and periodontal disease

    Directory of Open Access Journals (Sweden)

    Harpreet Singh Grover

    2013-01-01

    Full Text Available Both diabetes and periodontitis are chronic diseases. Diabetes has many adverse effects on the periodontium, and conversely periodontitis may have deleterious effects further aggravating the condition in diabetics. The potential common pathophysiologic pathways include those associated with inflammation, altered host responses, altered tissue homeostasis, and insulin resistance. This review examines the relationship that exists between periodontal diseases and diabetes mellitus with a focus on potential common pathophysiologic mechanisms.

  16. Phenanthrene causes ocular developmental toxicity in zebrafish embryos and the possible mechanisms involved

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Lixing [State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005 (China); Wang, Chonggang [State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005 (China); State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen (China); Zhang, Youyu; Wu, Meifang [State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005 (China); Zuo, Zhenghong, E-mail: zuozhenghong@xmu.edu.cn [State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen 361005 (China); State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen (China)

    2013-10-15

    Highlights: • Phe exposure caused obvious morphological changes in the retina. • Phe exposure caused apoptosis and reduction of cell proliferation in the retina. • Phe causes ocular toxicity might be via the AhR/Zeb1/Mitf/Pax6 signaling pathway. • AhR is a repressor of Zeb1. -- Abstract: Recent studies show that polycyclic aromatic hydrocarbons (PAHs) may be a candidate cause of developmental defects of the retina, but the mechanism is still unclear. We evaluated the mechanism(s) underlying PAH-induced retinal development defects due to exposure to environmental concentrations of Phenanthrene (Phe) in zebrafish. We found that exposure to environmental concentrations of Phe caused obvious morphological changes, developmental retardation, apoptosis, and reduction of cell proliferation in the retina. Our results indicated that Phe could cause visual system developmental defects. Phe exposure up-regulated aryl hydrocarbon receptor (AhR) and microphthalmia-associated transcription factor (Mtif) expression, and down-regulated zinc finger E-box binding homeobox 1 (Zeb1) and paired box 6 (Pax6). Moreover, we demonstrated that AhR was a repressor of Zeb1. We propose that Phe's ocular toxicity is mediated by up-regulating AhR, which then down-regulates Zeb1, in turn inducing Mitf expression while inhibiting Pax6 expression.

  17. An intermolecular binding mechanism involving multiple LysM domains mediates carbohydrate recognition by an endopeptidase

    DEFF Research Database (Denmark)

    Wong, Jaslyn E M M; Midtgaard, Søren Roi; Gysel, Kira

    2015-01-01

    LysM domains, which are frequently present as repetitive entities in both bacterial and plant proteins, are known to interact with carbohydrates containing N-acetylglucosamine (GlcNAc) moieties, such as chitin and peptidoglycan. In bacteria, the functional significance of the involvement of multi......LysM domains, which are frequently present as repetitive entities in both bacterial and plant proteins, are known to interact with carbohydrates containing N-acetylglucosamine (GlcNAc) moieties, such as chitin and peptidoglycan. In bacteria, the functional significance of the involvement...... of multiple LysM domains in substrate binding has so far lacked support from high-resolution structures of ligand-bound complexes. Here, a structural study of the Thermus thermophilus NlpC/P60 endopeptidase containing two LysM domains is presented. The crystal structure and small-angle X-ray scattering...... solution studies of this endopeptidase revealed the presence of a homodimer. The structure of the two LysM domains co-crystallized with N-acetyl-chitohexaose revealed a new intermolecular binding mode that may explain the differential interaction between LysM domains and short or long chitin oligomers...

  18. Molecular mechanisms involved in secretory vesicle recruitment to the plasma membrane in beta-cells.

    Science.gov (United States)

    Varadi, Aniko; Ainscow, E K; Allan, V J; Rutter, G A

    2002-04-01

    Glucose stimulates the release of insulin in part by activating the recruitment of secretory vesicles to the cell surface. While this movement is known to be microtubule-dependent, the molecular motors involved are undefined. Active kinesin was found to be essential for vesicle translocation in live beta-cells, since microinjection of cDNA encoding dominant-negative KHC(mut) (motor domain of kinesin heavy chain containing a Thr(93)-->Asn point mutation) blocked vesicular movements. Moreover, expression of KHC(mut) strongly inhibited the sustained, but not acute, stimulation of secretion by glucose. Thus, vesicles released during the first phase of insulin secretion exist largely within a translocation-independent pool. Kinesin-driven anterograde movement of vesicles is then necessary for the sustained (second phase) of insulin release. Kinesin may, therefore, represent a novel target for increases in intracellular ATP concentrations in response to elevated extracellular glucose and may be involved in the ATP-sensitive K+channel-independent stimulation of secretion by the sugar.

  19. Mechanisms involved in carbachol-induced Ca2+ sensitization of contractile elements in rat proximal and distal colon

    OpenAIRE

    Takeuchi, Tadayoshi; Kushida, Masahiko; Hirayama, Nobue; Kitayama, Muneyoshi; Fujita, Akikazu; Hata, Fumiaki

    2004-01-01

    Mechanisms involved in Ca2+ sensitization of contractile elements induced by the activation of muscarinic receptors in membrane-permeabilized preparations of the rat proximal and distal colon were studied.In α-toxin-permeabilized preparations from the rat proximal and distal colon, Ca2+ induced a rapid phasic and subsequent tonic component. After Ca2+-induced contraction reached a plateau, guanosine 5′-triphosphate (GTP) and carbachol (CCh) in the presence of GTP further contracted preparatio...

  20. Connecting mechanics and bone cell activities in the bone remodeling process: an integrated finite element modeling.

    Science.gov (United States)

    Hambli, Ridha

    2014-01-01

    Bone adaptation occurs as a response to external loadings and involves bone resorption by osteoclasts followed by the formation of new bone by osteoblasts. It is directly triggered by the transduction phase by osteocytes embedded within the bone matrix. The bone remodeling process is governed by the interactions between osteoblasts and osteoclasts through the expression of several autocrine and paracrine factors that control bone cell populations and their relative rate of differentiation and proliferation. A review of the literature shows that despite the progress in bone remodeling simulation using the finite element (FE) method, there is still a lack of predictive models that explicitly consider the interaction between osteoblasts and osteoclasts combined with the mechanical response of bone. The current study attempts to develop an FE model to describe the bone remodeling process, taking into consideration the activities of osteoclasts and osteoblasts. The mechanical behavior of bone is described by taking into account the bone material fatigue damage accumulation and mineralization. A coupled strain-damage stimulus function is proposed, which controls the level of autocrine and paracrine factors. The cellular behavior is based on Komarova et al.'s (2003) dynamic law, which describes the autocrine and paracrine interactions between osteoblasts and osteoclasts and computes cell population dynamics and changes in bone mass at a discrete site of bone remodeling. Therefore, when an external mechanical stress is applied, bone formation and resorption is governed by cells dynamic rather than adaptive elasticity approaches. The proposed FE model has been implemented in the FE code Abaqus (UMAT routine). An example of human proximal femur is investigated using the model developed. The model was able to predict final human proximal femur adaptation similar to the patterns observed in a human proximal femur. The results obtained reveal complex spatio-temporal bone

  1. Extracellular matrix proteins modulate asthmatic airway smooth muscle cell proliferation via an autocrine mechanism

    NARCIS (Netherlands)

    Johnson, Peter R A; Burgess, Janette K; Underwood, P Anne; Au, Wendy; Poniris, Maree H; Tamm, Michael; Ge, Qi; Roth, Michael; Black, Judith L

    2004-01-01

    BACKGROUND: Airway remodeling is a key feature of persistent asthma and includes alterations in the extracellular matrix protein profile around the airway smooth muscle (ASM) and hyperplasia of the ASM. We have previously shown that nonasthmatic ASM cells in culture produce a range of extracellular

  2. Differentially expressed fibroblast growth factors regulate skeletal muscle development through autocrine and paracrine mechanisms

    OpenAIRE

    1996-01-01

    Several FGF family members are expressed in skeletal muscle; however, the roles of these factors in skeletal muscle development are unclear. We examined the RNA expression, protein levels, and biological activities of the FGF family in the MM14 mouse skeletal muscle cell line. Proliferating skeletal muscle cells express FGF-1, FGF-2, FGF-6, and FGF-7 mRNA. Differentiated myofibers express FGF-5, FGF-7, and reduced levels of FGF-6 mRNA. FGF-3, FGF-4, and FGF-8 were not detectable by RT-PCR in ...

  3. Adiponectin self-regulates its expression and multimerization in adipose tissue: an autocrine/paracrine mechanism?

    Science.gov (United States)

    Lin, Huan; Li, Zhen

    2012-01-01

    Adiponectin, a 30-kDa peptide hormone discovered in the mid 1990s, is secreted abundantly and exclusively by adipose tissue. Adiponectin exists in three major forms: a low molecular weight (LMW) trimer, a medium molecular weight (MMW) hexamer, and a high molecular weight (HMW) 18-36 oligomer. The HMW oligomer has the most potent insulin-sensitizing activity therefore impaired adiponectin multimerization may lead to impaired glycemic control. Decreased ratio of HMW/total adiponectin has been observed in patients with obesity, type-2 diabetes mellitus, cardiovascular diseases and insulin resistance-related metabolic syndrome. Previous studies have indicated that berberine or aminoimidazole carboxamide ribonucleotide (AICAR)-induced activation of AMP-activated protein kinase (AMPK) suppresses the expression of adiponectin but promotes adiponectin multimerization in adipocytes. Since adiponectin activates AMPK through adiponectin receptors (AdipoRs) in the membranes of adipocytes, we speculate that adiponectin self-regulates its expression and multimerization in adipose tissue. The hypothesis suggests a potential drug target for treating insulin resistance and provides new interpretation of several clinical observations. In addition, we propose a rapid method for one-step detection of the distribution of adiponectin oligomers in approximately 30 min, based on the open sandwich immunoassay and fluorescence resonance energy transfer technology. With the development of this new method, the ratio of HMW/total adiponectin may be applied in clinical diagnosis as a novel biomarker for insulin resistance and metabolic disorders.

  4. Autocrine signaling mechanism of vitamin D in the bovine innate immune response

    Science.gov (United States)

    Vitamin D is 25-hydroxylated in the liver to provide the precursor for renal production of the steroid hormone 1,25-dihydroxyvitamin D (1,25(OH)2D3) by 1alpha-hydroxylase. This highly regulated endocrine pathway is key to controlling many aspects of calcium homeostasis. In contrast to the hormone’...

  5. GR-127935-sensitive mechanism mediating hypotension in anesthetized rats: are 5-HT5B receptors involved?

    Science.gov (United States)

    Sánchez-Maldonado, Carolina; López-Sánchez, Pedro; Anguiano-Robledo, Liliana; Leopoldo, Marcello; Lacivita, Enza; Terrón, José A

    2015-04-01

    The 5-HT1B/1D receptor antagonist, GR-127935, inhibits hypotensive responses produced by the 5-HT1A, 5-HT1B/1D and 5-HT7 receptor agonist, and 5-HT5A/5B receptor ligand, 5-carboxamidotryptamine (5-CT), in rats. This work further characterized the above mechanism using more selective 5-HT1B and 5-HT1D receptor antagonists. Also, expression of 5-HT5A and 5-HT5B receptor mRNAs in blood vessels was searched by reverse transcription polymerase chain reaction. Decreases in diastolic blood pressure induced by 5-CT (0.001-10 μg/kg, intravenously) were analyzed in anesthetized rats that had received intravenous vehicle (1 mL/kg), SB-224289 (5-HT1B antagonist; 0.3 and 1.0 mg/kg), BRL15572 (5-HT1D antagonist; 0.3 and 1.0 mg/kg), SB-224289 + BRL15572 (0.3 mg/kg, each), or SB-224289 + BRL15572 (0.3 mg/kg, each) + GR-127935 (1 mg/kg). Because only the latter treatment inhibited 5-CT-induced hypotension, suggestive of a mechanism unrelated to 5-HT1B/1D receptors, the effects of antagonists/ligands at 5-HT5A (SB-699551, 1 mg/kg), 5-HT6 (SB-399885, 1 mg/kg), and 5-HT1B/1D/5A/5B/7 receptors (ergotamine, 0.1 mg/kg) on 5-CT-induced hypotension were tested. Interestingly, only ergotamine blocked 5-CT-induced responses; this effect closely paralleled that of SB-224289 + BRL-15572 + GR-127935. Neither did ergotamine nor GR-127935 inhibit hypotensive responses induced by the 5-HT7 receptor agonist, LP-44. Faint but clear bands corresponding to 5-HT5A and 5-HT5B receptor mRNAs in aorta and mesenteric arteries were detected. Results suggest that the GR-127935-sensitive mechanism mediating hypotension in rats is unrelated to 5-HT1B, 5-HT1D, 5-HT5A, 5-HT6, and 5-HT7 receptors. This mechanism, however, resembles putative 5-HT5B receptors.

  6. A novel mechanism involved in the coupling of mitochondrial biogenesis to oxidative phosphorylation

    Directory of Open Access Journals (Sweden)

    Jelena Ostojić

    2014-01-01

    Full Text Available Mitochondria are essential organelles that are central to a multitude of cellular processes, including oxidative phosphorylation (OXPHOS, which produces most of the ATP in animal cells. Thus it is important to understand not only the mechanisms and biogenesis of this energy production machinery but also how it is regulated in both physiological and pathological contexts. A recent study by Ostojić et al. [Cell Metabolism (2013 18, 567-577] has uncovered a regulatory loop by which the biogenesis of a major enzyme of the OXPHOS pathway, the respiratory complex III, is coupled to the energy producing activity of the mitochondria.

  7. Involvement of TACE in colon inflammation: a novel mechanism of regulation via SIRT-1 activation.

    Science.gov (United States)

    Sharma, Manoranjan; Mohapatra, Jogeswar; Wagh, Akshaya; Patel, Hiren M; Pandey, Dheerendra; Kadam, Shekhar; Argade, Anil; Deshpande, Shrikalp S; Shah, Gourang B; Chatterjee, Abhijit; Jain, Mukul R

    2014-03-01

    TNF-α converting enzyme (TACE) processes the membrane TNF-α to release the bioactive soluble TNF-α. Several evidences suggest the involvement of TNF-α and TACE in inflammatory bowel disease (IBD). Tissue inhibitor of metalloproteinase (TIMP)-3, an endogenous inhibitor of TACE, is positively associated with silent information regulator (SIRT)-1. We aimed to study the expression of TACE, TIMP-3 and SIRT-1 at different stages of colitis and how TACE is regulated in response to SIRT-1 activation. Acute colitis was induced by 3.5% dextran sulfate sodium (DSS) in drinking water for 5days and levels of cytokines and mRNA expression of TACE, TIMP-3 and SIRT-1 were measured in colon at different time intervals. Next, the effect of SIRT-1 activator (resveratrol) or a selective TACE inhibitor (compound 11p) treatment was evaluated. Elevated levels of TNF-α, interleukin (IL)-6, IL-1β, interferon (IFN)-γ and IL-17 were observed during DSS exposure phase which restored to the normal level after DSS removal. A significant increase in TACE and suppression in TIMP-3 and SIRT-1 mRNA level was observed during DSS exposure phase which reverts back to normal towards the remission phase. Treatment with resveratrol significantly elevated SIRT-1 and TIMP-3 and suppressed TACE mRNA expression and was associated with amelioration of disease. Furthermore, treatment with selective TACE inhibitor significantly suppressed body weight loss, disease activity index, colonic myeloperoxidase activity and the elevated levels of cytokines after DSS challenge. These results strongly emphasize the involvement of TACE in colon inflammation and inhibition of TACE directly or indirectly via SIRT-1 activation ameliorates colitis.

  8. Mechanism of Anti-glioblastoma Effect of Temzolomide Involved in ROS-Mediated SIRT 1 Pathway

    Directory of Open Access Journals (Sweden)

    Yuan Jiang

    2014-03-01

    Full Text Available Objective: To explore the new molecular mechanism of anti-tumor effect of temzolomide (TMZon glioblastoma cell strain. Methods: MTT methods and Hoechst 33342 staining method were applied to determine the effect of TMZ on the proliferation and apoptosis of glioblastoma cell strains U251 and SHG44, while flow cytometry was used to detect the impact of TMZ on cellular cycles. Additionally, DCFH-DA probe was adopted to test intracellular reactive oxygen species (ROS level while Real-time PCR and Western blot tests were applied to determine the influence of TMZ on SIRT1 expression. Results: TMZ in different concentrations added into glioblastoma cell strain for 72 h could concentration-dependently inhibit the proliferation of glioblastoma cells, 100 μmol/L of which could also block cells in phase G2/M and improve cellular apoptosis. In addition, TMZ could evidently increase intracellular ROS level so as to activate SIRT1. Conclusion: The mechanism of anti-tumor effect of TMZ on glioblastoma may be associated with ROS-induced SIRT1 pathway, providing theoretical basis for the clinical efficacy of TMZ.

  9. Mechanism of Anti-glioblastoma Effect of Temzolomide Involved in ROS-Mediated SIRT 1 Pathway

    Institute of Scientific and Technical Information of China (English)

    Jiang Yuan; Sun Yan; Yuan Yuan

    2014-01-01

    Objective:To explore the new molecular mechanism of anti-tumor effect of temzolomide (TMZ) on glioblastoma cell strain. Methods:MTT methods and Hoechst 33342 staining method were applied to determine the effect of TMZ on the proliferation and apoptosis of glioblastoma cell strains U251 and SHG44, while lfow cytometry was used to detect the impact of TMZ on cellular cycles. Additionally, DCFH-DA probe was adopted to test intracellular reactive oxygen species (ROS) level while Real-time PCR and Western blot tests were applied to determine the inlfuence of TMZ on SIRT1 expression. Results: TMZ in different concentrations added into glioblastoma cell strain for 72 h could concentration-dependently inhibit the proliferation of glioblastoma cells, 100 μmol/L of which could also block cells in phase G2/M and improve cellular apoptosis. In addition, TMZ could evidently increase intracellular ROS level so as to activate SIRT1. Conclusion: The mechanism of anti-tumor effect of TMZ on glioblastoma may be associated with ROS-induced SIRT1 pathway, providing theoretical basis for the clinical efifcacy of TMZ.

  10. Gut bitter taste receptor signalling induces ABCB1 through a mechanism involving CCK.

    Science.gov (United States)

    Jeon, Tae-Il; Seo, Young-Kyo; Osborne, Timothy F

    2011-08-15

    T2Rs (bitter taste-sensing type 2 receptors) are expressed in the oral cavity to prevent ingestion of dietary toxins through taste avoidance. They are also expressed in other cell types, including gut enteroendocrine cells, where their physiological role is enigmatic. Previously, we proposed that T2R-dependent CCK (cholecystokinin) secretion from enteroendocrine cells limits absorption of dietary toxins, but an active mechanism was lacking. In the present study we show that T2R signalling activates ABCB1 (ATP-binding cassette B1) in intestinal cells through a CCK signalling mechanism. PTC (phenylthiocarbamide), an agonist for the T2R38 bitter receptor, increased ABCB1 expression in both intestinal cells and mouse intestine. PTC induction of ABCB1 was decreased by either T2R38 siRNA (small interfering RNA) or treatment with YM022, a gastrin receptor antagonist. Thus gut ABCB1 is regulated through signalling by CCK/gastrin released in response to PTC stimulation of T2R38 on enteroendocrine cells. We also show that PTC increases the efflux activity of ABCB1, suggesting that T2R signalling limits the absorption of bitter tasting/toxic substances through modulation of gut efflux membrane transporters.

  11. Potassium channel and NKCC cotransporter involvement in ocular refractive control mechanisms.

    Directory of Open Access Journals (Sweden)

    Sheila G Crewther

    Full Text Available Myopia affects well over 30% of adult humans globally. However, the underlying physiological mechanism is little understood. This study tested the hypothesis that ocular growth and refractive compensation to optical defocus can be controlled by manipulation of potassium and chloride ion-driven transretinal fluid movements to the choroid. Chicks were raised with +/-10D or zero power optical defocus rendering the focal plane of the eye in front of, behind, or at the level of the retinal photoreceptors respectively. Intravitreal injections of barium chloride, a non-specific inhibitor of potassium channels in the retina and RPE or bumetanide, a selective inhibitor of the sodium-potassium-chloride cotransporter were made, targeting fluid control mechanisms. Comparison of refractive compensation to 5 mM Ba(2+ and 10(-5 M bumetanide compared with control saline injected eyes shows significant change for both positive and negative lens defocus for Ba(2+ but significant change only for negative lens defocus with bumetanide (Rx(SAL(-10D = -8.6 +/- .9 D; Rx(Ba2+(-10D = -2.9 +/- .9 D; Rx(Bum(-10D = -2.9 +/- .9 D; Rx(SAL(+10D = +8.2 +/- .9 D; Rx(Ba2+(+10D = +2.8 +/- 1.3 D; Rx(Bum(+10D = +8.0 +/- .7 D. Vitreous chamber depths showed a main effect for drug conditions with less depth change in response to defocus shown for Ba(2+ relative to Saline, while bumetanide injected eyes showed a trend to increased depth without a significant interaction with applied defocus. The results indicate that both K channels and the NKCC cotransporter play a role in refractive compensation with NKCC blockade showing far more specificity for negative, compared with positive, lens defocus. Probable sites of action relevant to refractive control include the apical retinal pigment epithelium membrane and the photoreceptor/ON bipolar synapse. The similarities between the biometric effects of NKCC inhibition and biometric reports of the blockade of the retinal ON response, suggest a

  12. Neural Mechanisms of Temporomandibular Joint and Masticatory Muscle Pain: A Possible Role for Peripheral Glutamate Receptor Mechanisms

    Directory of Open Access Journals (Sweden)

    David K Lam

    2005-01-01

    Full Text Available The purpose of the present review is to correlate recent knowledge of the role of peripheral ionotropic glutamate receptors in the temporomandibular joint and muscle pain from animal and human experimental pain models with findings in patients. Chronic pain is common, and many people suffer from chronic pain conditions involving deep craniofacial tissues such as temporomandibular disorders or fibromyalgia. Animal and human studies have indicated that the activation of peripheral ionotropic glutamate receptors in deep craniofacial tissues may contribute to muscle and temporomandibular joint pain and that sex differences in the activation of glutamate receptors may be involved in the female predominance in temporomandibular disorders and fibromyalgia. A peripheral mechanism involving autocrine and/or paracrine regulation of nociceptive neuronal excitability via injury or inflammation-induced release of glutamate into peripheral tissues that may contribute to the development of craniofacial pain is proposed.

  13. Breast cancer: mechanisms involved in action of phytoestrogens and epigenetic changes.

    Science.gov (United States)

    Dagdemir, Aslihan; Durif, Julie; Ngollo, Marjolaine; Bignon, Yves-Jean; Bernard-Gallon, Dominique

    2013-01-01

    In this review, we consider phytoestrogens and different epigenetic modifications in breast cancer. Epigenetic phenomena are mediated by several molecular mechanisms comprising histone modifications, small non-coding or anti-sense RNA and DNA methylation. These different modifications are closely interrelated. De-regulation of gene expression is a hallmark of cancer. Although genetic lesions have been the focus of cancer research for many years, it has become increasingly recognized that aberrant epigenetic modifications also play major roles in breast carcinogenesis. The incidence and mortality rates of breast cancer are high in the Western world compared with countries in Asia. There are also differences in the breast cancer incidence rates in different Western countries. This could be related to phytoestrogens.

  14. [Cytological mechanisms involved in assimilation of n-alkanes by yeasts].

    Science.gov (United States)

    Meĭsel', M N; Medvedeva, G A; Kozlova, T M

    1976-01-01

    The paper describes cytological mechanism of adaptation of yeasts to assimilation of aliphatic hydrocarbons added to a growth medium as a sole source of carbon. The process was studied by light optical and electron microscopy, employing fluorescent labelling and electron microscopy contrasting. Two types of yeasts were found, which differed by the response of the cell walls to hydrocarbons: those that formed "channels" and those that did not form them. Cytological response to hydrocarbon assimilation was detected also in the mitochondria and canals of the endoplasmic reticulum. Components of the Golgi apparatus may also participate in this process, in particular, in formation of peroxisomes (microbodies). Close contacts of the yeast cells with the hydrocarbon being assimilated is important; assimilation may start in a close vicinity of the cell walls. The rate of flavin production by Candida tropicalis 303 IBFM increases during growth on solid paraffins, beginning with C20-paraffin.

  15. Critical review on the physical and mechanical factors involved in tissue engineering of cartilage.

    Science.gov (United States)

    Gaut, Carrie; Sugaya, Kiminobu

    2015-01-01

    Articular cartilage defects often progress to osteoarthritis, which negatively impacts quality of life for millions of people worldwide and leads to high healthcare expenditures. Tissue engineering approaches to osteoarthritis have concentrated on proliferation and differentiation of stem cells by activation and suppression of signaling pathways, and by using a variety of scaffolding techniques. Recent studies indicate a key role of environmental factors in the differentiation of mesenchymal stem cells to mature cartilage-producing chondrocytes. Therapeutic approaches that consider environmental regulation could optimize chondrogenesis protocols for regeneration of articular cartilage. This review focuses on the effect of scaffold structure and composition, mechanical stress and hypoxia in modulating mesenchymal stem cell fate and the current use of these environmental factors in tissue engineering research.

  16. Mechanisms Involved in Trichloroethylene-Induced Liver Cancer: Importance to Environmental Cleanup

    Energy Technology Data Exchange (ETDEWEB)

    Bull, Richard J.; Thrall, Brian D.

    2000-06-01

    The project is organized around two interrelated tasks: Task 1 develops the basic dosimetry parameters and provides in vivo data describing the mode of action tumorigenic and for the metabolites of TCE that produce liver cancer in mice, dichloroacetate (DCA) and trichloroacetate (TCA). Early work suggested that TCA was primarily responsible for TCE-induced liver tumor. More recent, mechanistic observations indicated that DCA played a prominent role. Therefore, studies were designed to determine whether the effects of DCA were mediated through a mode of action that affects primarily tumor growth rates. Task 2 seeks specific evidence that TCA and DCA are capable of promoting the growth of spontaneously initiated cells from mouse liver, in vitro. The data provide the clearest evidence that both metabolites act by a mechanism of selection rather than mutation. These data are necessary to select between a linear (i.e. no threshold) and non-linear low-dose extrapolation models.

  17. The Micro-mechanism Involved and Wollastonite Signature in the Calcareous Precipitates of Marine Isolates.

    Science.gov (United States)

    Sarayu, K; Iyer, Nagesh R; Annaselvi, M; Ramachandra Murthy, A

    2016-03-01

    Micro-mechanical studies connecting the influence of extrinsic factors over intrinsic factors on 30 calcareous isolates obtained from marine sediment biofilms of the Bay of Bengal (Indian Ocean) revealed that the fate of calcareous crystal precipitation is highly dependent on factors like extracellular polysaccharides (EPS), organic carbon and nutrition. Further studies exemplified that EPS and the organic carbon secreted by the isolates controlled the dissemination of the calcareous crystals precipitated. From the study, it is evident that an EPS concentration of 7-15 mg l(-1) was found to enhance the dissemination of the calcareous crystals. Atomic force micrographs explain the nucleation behaviour and morphology of the calcareous crystals precipitated. X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDAX) showed that the crystals were mainly composed of calcite and partially wollastonite.

  18. A tumor-suppressing mechanism in Drosophila involving cell competition and the Hippo pathway

    Science.gov (United States)

    Menéndez, Javier; Pérez-Garijo, Ainhoa; Calleja, Manuel; Morata, Ginés

    2010-01-01

    Mutant larvae for the Drosophila gene lethal giant larva (lgl) develop neoplastic tumors in imaginal discs. However, lgl mutant clones do not form tumors when surrounded by wild-type tissue, suggesting the existence of a tumor-suppressing mechanism. We have investigated the tumorigenic potential of lgl mutant cells by generating wing compartments that are entirely mutant for lgl and also inducing clones of various genetic combinations of lgl− cells. We find that lgl− compartments can grow indefinitely but lgl− clones are eliminated by cell competition. lgl mutant cells may form tumors if they acquire constitutive activity of the Ras pathway (lgl− UAS-rasV12), which confers proliferation advantage through inhibition of the Hippo pathway. Yet, the majority of lgl− UAS-rasV12 clones are eliminated in spite of their high proliferation rate. The formation of a tumor requires in addition the formation of a microenvironment that allows mutant cells to evade cell competition. PMID:20679206

  19. Effects of high fluoride intake on child mental work capacity: preliminary investigation into the mechanisms involved

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.; Li, X.J.; Wei, S.Q. [Child & Adolescent Hygiene Teaching Research Station, Chengdu (China)

    2008-10-15

    A study was carried out on 157 children, age 12-13, from a coal-burning fluorosis endemic area together with an experiment looking into the effect of high fluoride intake in animals. The results showed that early, prolonged high fluoride intake causes a decrease in a child's mental work capacity and that prolonged high uptake of fluoride causes a child's levels of hair zinc to drop. A multifactoral correlative analysis demonstrated a direct correlation between hair zinc and mental work capacity. The decrease of 5-hydroxyindoleacetic acid and the increase of norepinephrine in animal brains exposed to high levels of fluoride suggest a possible mechanism for mental work capacity deficits in children. However, further research is necessary.

  20. Mechanical stretch upregulates proteins involved in Ca2+ sensitization in urinary bladder smooth muscle hypertrophy.

    Science.gov (United States)

    Boopathi, Ettickan; Gomes, Cristiano; Zderic, Stephen A; Malkowicz, Bruce; Chakrabarti, Ranjita; Patel, Darshan P; Wein, Alan J; Chacko, Samuel

    2014-09-15

    Partial bladder outlet obstruction (pBOO)-induced remodeling of bladder detrusor smooth muscle (DSM) is associated with the modulation of cell signals regulating contraction. We analyzed the DSM from obstructed murine urinary bladders for the temporal regulation of RhoA GTPase and Rho-activated kinase (ROCK), which are linked to Ca(2+) sensitization. In addition, the effects of equibiaxial cell stretch, a condition thought to be associated with pBOO-induced bladder wall smooth muscle hypertrophy and voiding frequency, on the expression of RhoA, ROCK, and C-kinase-activated protein phosphatase I inhibitor (CPI-17) were investigated. DSM from 1-, 3-, 7-, and 14-day obstructed male mice bladders and benign prostatic hyperplasia (BPH)-induced obstructed human bladders revealed overexpression of RhoA and ROCK-β at the mRNA and protein levels compared with control. Primary human bladder myocytes seeded onto type I collagen-coated elastic silicone membranes were subjected to cyclic equibiaxial stretch, mimicking the cellular mechanical stretch in the bladder in vivo, and analyzed for the expression of RhoA, ROCK-β, and CPI-17. Stretch caused a significant increase of RhoA, ROCKβ, and CPI-17 expression. The stretch-induced increase in CPI-17 expression occurs at the transcriptional level and is associated with CPI-17 promoter binding by GATA-6 and NF-κB, the transcription factors responsible for CPI-17 gene transcription. Cell stretch caused by bladder overdistension in pBOO is the likely mechanism for initiating overexpression of the signaling proteins regulating DSM tone.

  1. A pathogenic mechanism in Huntington's disease involves small CAG-repeated RNAs with neurotoxic activity.

    Science.gov (United States)

    Bañez-Coronel, Mónica; Porta, Silvia; Kagerbauer, Birgit; Mateu-Huertas, Elisabet; Pantano, Lorena; Ferrer, Isidre; Guzmán, Manuel; Estivill, Xavier; Martí, Eulàlia

    2012-01-01

    Huntington's disease (HD) is an autosomal dominantly inherited disorder caused by the expansion of CAG repeats in the Huntingtin (HTT) gene. The abnormally extended polyglutamine in the HTT protein encoded by the CAG repeats has toxic effects. Here, we provide evidence to support that the mutant HTT CAG repeats interfere with cell viability at the RNA level. In human neuronal cells, expanded HTT exon-1 mRNA with CAG repeat lengths above the threshold for complete penetrance (40 or greater) induced cell death and increased levels of small CAG-repeated RNAs (sCAGs), of ≈21 nucleotides in a Dicer-dependent manner. The severity of the toxic effect of HTT mRNA and sCAG generation correlated with CAG expansion length. Small RNAs obtained from cells expressing mutant HTT and from HD human brains significantly decreased neuronal viability, in an Ago2-dependent mechanism. In both cases, the use of anti-miRs specific for sCAGs efficiently blocked the toxic effect, supporting a key role of sCAGs in HTT-mediated toxicity. Luciferase-reporter assays showed that expanded HTT silences the expression of CTG-containing genes that are down-regulated in HD. These results suggest a possible link between HD and sCAG expression with an aberrant activation of the siRNA/miRNA gene silencing machinery, which may trigger a detrimental response. The identification of the specific cellular processes affected by sCAGs may provide insights into the pathogenic mechanisms underlying HD, offering opportunities to develop new therapeutic approaches.

  2. Growth capacity and biochemical mechanisms involved in rhizobia tolerance to salinity and water deficit.

    Science.gov (United States)

    Mhamdi, Rakia; Nouairi, Issam; ben Hammouda, Thouraya; Mhamdi, Ridha; Mhadhbi, Haythem

    2015-04-01

    The aim of the present study was to evaluate abiotic stress tolerance of rhizobial strains belonging to Mesorhizobium, Sinorhizobium, and Rhizobium genera, as well as to investigate specie specific stress response mechanisms. Effect of NaCl and PEG on growth capacity, protein, lipid peroxydation (MDA), membrane fatty acid composition and antioxidant enzymes were investigated. Growth capacity and viability of overall rhizobia strains decreased proportionally to the increase of NaCl and PEG levels in the medium. Sinorhizobium strains appeared the most tolerant, where 4H41strain was able to grow at 800 mM NaCl and 40% PEG. On the other hand, growth of R. gallicum and M. mediterraneum was inhibited by 200 mM NaCl. The content of MDA was unchanged in Sinorhizobium strains under both stresses. For Mesorhizobium, only PEG treatment increased the content of MDA. Amount of the C19:0 cyclo fatty-acid was increased in both Sinorhizobium and Mesorhizobium tolerant strains. NaCl stress increased Superoxide dismutase (SOD) activity of overall species; especially the most tolerant strain 4H41. Both treatments increased catalase (CAT) activity in 4H41, TII7, and 835 strains. Obtained results suggest that major response of tolerant Sinorhizobium and Mesorhizobium strains to NaCl and PEG stresses is a preferential accumulation of the C19:0 cyclo fatty acid within bacterial membrane as mechanism to reduce fluidity and maintain integrity. Cell integrity and functioning is also assured by maintaining and/or increasing activity of SOD and CAT antioxidant enzymes for tolerant strains to omit structural and functional damages related to reactive oxygen species overproduced under stressful conditions.

  3. Attentional Biases toward Attractive Alternatives and Rivals: Mechanisms Involved in Relationship Maintenance among Chinese Women.

    Directory of Open Access Journals (Sweden)

    Yidan Ma

    Full Text Available A long-term romantic relationship can offer many benefits to committed individuals. Thus, humans possess relationship maintenance mechanisms to protect against threats from those who serve as attractive alternatives or intrasexual rivals. Many studies have indicated that romantic love can act as a commitment device to activate these mechanisms. To examine the attentional bias associated with relationship maintenance among 108 college students (49 single and 59 committed females in China, we used a semantic priming procedure to activate mental representations associated with romantic love and then asked participants to complete a dot-probe task for the purpose of making a distinction between the engage and disengage components of attention. No significant engaging effects toward attractive faces were observed among committed females, but the following significant disengaging effects were found: when primed with romantic love, single females showed increased attention toward and difficulty in disengaging from attractive male faces, whereas females already in a committed relationship did not alter their attention, remaining as inattentive to attractive alternatives as they were in the baseline condition. In addition, committed females responded to love priming by exhibiting difficulty in disengaging from attractive rivals. The present findings provide evidence in the Chinese cultural context for the existence of early-stage attentional processes in the domain of relationship maintenance that committed Chinese females protected an ongoing relationship by not only being inattentive to attractive males who could serve as attractive alternatives, but also being more attentive to attractive females who could be potential rivals when mental representations associated with romantic love were primed.

  4. Autocrine induction of invasion and metastasis by tumor-associated trypsin inhibitor in human colon cancer cells.

    Science.gov (United States)

    Gouyer, V; Fontaine, D; Dumont, P; de Wever, O; Fontayne-Devaud, H; Leteurtre, E; Truant, S; Delacour, D; Drobecq, H; Kerckaert, J-P; de Launoit, Y; Bracke, M; Gespach, C; Desseyn, J-L; Huet, G

    2008-07-03

    From the conditioned medium of the human colon carcinoma cells, HT-29 5M21 (CM-5M21), expressing a spontaneous invasive phenotype, tumor-associated trypsin inhibitor (TATI) was identified and characterized by proteomics, cDNA microarray approaches and functional analyses. Both CM-5M21 and recombinant TATI, but not the K18Y-TATI mutant at the protease inhibitor site, trigger collagen type I invasion by several human adenoma and carcinoma cells of the colon and breast, through phosphoinositide-3-kinase, protein kinase C and Rho-GTPases/Rho kinase-dependent pathways. Conversely, the proinvasive action of TATI in parental HT29 cells was alleviated by the TATI antibody PSKAN2 and the K18Y-TATI mutant. Stable expression of K18Y-TATI in HT-29 5M21 cells downregulated tumor growth, angiogenesis and the expression of several metastasis-related genes, including CSPG4 (13.8-fold), BMP-7 (9.7-fold), the BMP antagonist CHORDIN (5.2-fold), IGFBP-2 and IGF2 (9.6- and 4.6-fold). Accordingly, ectopic expression of KY-TATI inhibited the development of lung metastases from HT-29 5M21 tumor xenografts in immunodeficient mice. These findings identify TATI as an autocrine transforming factor potentially involved in early and late events of colon cancer progression, including local invasion of the primary tumor and its metastatic spread. Targeting TATI, its molecular partners and effectors may bring novel therapeutic applications for high-grade human solid tumors in the digestive and urogenital systems.

  5. Mechanisms involved in the anti-inflammatory action of inhaled tea tree oil in mice.

    Science.gov (United States)

    Golab, Mateusz; Skwarlo-Sonta, Krystyna

    2007-03-01

    Tea tree oil (TTO) is well known as an antimicrobial and immunomodulatory agent. In the present study we confirmed the anti-inflammatory properties of TTO and investigated the involvement of the hypothalamic-pituitary-adrenal (HPA) axis in the immunomodulatory action of TTO administered by inhalation. Sexually mature, 6-8-week-old, C(57)BI(10) x CBA/H (F(1)) male mice were used. One group of animals was injected intra-peritoneally (ip) with Zymosan to elicit peritoneal inflammation and was then submitted to four sessions of TTO inhalation (15 mins each). Some of the mice were simultaneously injected ip with Antalarmin, a CRH-1 receptor antagonist, to block HPA axis functions. Twenty-four hours after the injections the mice were killed by CO(2) asphyxia, and peritoneal leukocytes (PTLs) were isolated and counted. Levels of reactive oxygen species (ROS) and cyclooxygenase (COX) activity in PTLs were assessed by fluorimetric and colorimetric assays, respectively. The results obtained show that sessions of TTO inhalation exert a strong anti-inflammatory influence on the immune system stimulated by Zymosan injection, while having no influence on PTL number, ROS level, and COX activity in mice without inflammation. The HPA axis was shown to mediate the anti-inflammatory effect of TTO; Antalarmin abolished the influence of inhaled TTO on PTL number and their ROS production in mice with experimental peritonitis, but it had no effect on these parameters in mice without inflammation.

  6. An Overview of Sub-Cellular Mechanisms Involved in the Action of TTFields

    Directory of Open Access Journals (Sweden)

    Jack A. Tuszynski

    2016-11-01

    Full Text Available Long-standing research on electric and electromagnetic field interactions with biological cells and their subcellular structures has mainly focused on the low- and high-frequency regimes. Biological effects at intermediate frequencies between 100 and 300 kHz have been recently discovered and applied to cancer cells as a therapeutic modality called Tumor Treating Fields (TTFields. TTFields are clinically applied to disrupt cell division, primarily for the treatment of glioblastoma multiforme (GBM. In this review, we provide an assessment of possible physical interactions between 100 kHz range alternating electric fields and biological cells in general and their nano-scale subcellular structures in particular. This is intended to mechanistically elucidate the observed strong disruptive effects in cancer cells. Computational models of isolated cells subject to TTFields predict that for intermediate frequencies the intracellular electric field strength significantly increases and that peak dielectrophoretic forces develop in dividing cells. These findings are in agreement with in vitro observations of TTFields’ disruptive effects on cellular function. We conclude that the most likely candidates to provide a quantitative explanation of these effects are ionic condensation waves around microtubules as well as dielectrophoretic effects on the dipole moments of microtubules. A less likely possibility is the involvement of actin filaments or ion channels.

  7. IL-5-overexpressing mice exhibit eosinophilia and altered wound healing through mechanisms involving prolonged inflammation.

    Science.gov (United States)

    Leitch, Victoria D; Strudwick, Xanthe L; Matthaei, Klaus I; Dent, Lindsay A; Cowin, Allison J

    2009-02-01

    Leucocytes are essential in healing wounds and are predominantly involved in the inflammatory and granulation stages of wound repair. Eosinophils are granulocytic leucocytes and are specifically regulated by interleukin-5 (IL-5), a cytokine produced by T helper 2 (Th2) cells. To characterize more clearly the role of the IL-5 and eosinophils in the wound healing process, IL-5-overexpressing and IL-5-deficient mice were used as models of eosinophilia and eosinophil depletion, respectively. Our results reveal a significantly altered inflammatory response between IL-5-overexpressing and IL-5 knockout mice post-wounding. Healing was significantly delayed in IL-5-overexpressing mice with wounds gaping wider and exhibiting impaired re-epithelialization. A delay in collagen deposition was observed suggesting a direct effect on matrix synthesis. A significant increase in inflammatory cell infiltration, particularly eosinophils and CD4(+) cells, one of the main cell types which secrete IL-5, was observed in IL-5-overexpressing mice wounds suggesting that one of the main roles of IL-5 in wound repair may be to promote the infiltration of eosinophils into healing wounds. Healing is delayed in IL-5-overexpressing mice and this corresponds to significantly increased levels of eosinophils and CD4(+) cells within the wound site that may contribute to and exacerbate the inflammatory response, resulting in detrimental wound repair.

  8. An intermolecular binding mechanism involving multiple LysM domains mediates carbohydrate recognition by an endopeptidase

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Jaslyn E. M. M. [Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus (Denmark); Midtgaard, Søren Roi [University of Copenhagen, Universitetsparken 5, 2100 Copenhagen (Denmark); Gysel, Kira [Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus (Denmark); Thygesen, Mikkel B.; Sørensen, Kasper K.; Jensen, Knud J. [University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C (Denmark); Stougaard, Jens; Thirup, Søren; Blaise, Mickaël, E-mail: mickael.blaise@cpbs.cnrs.fr [Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus (Denmark)

    2015-03-01

    The crystal and solution structures of the T. thermophilus NlpC/P60 d, l-endopeptidase as well as the co-crystal structure of its N-terminal LysM domains bound to chitohexaose allow a proposal to be made regarding how the enzyme recognizes peptidoglycan. LysM domains, which are frequently present as repetitive entities in both bacterial and plant proteins, are known to interact with carbohydrates containing N-acetylglucosamine (GlcNAc) moieties, such as chitin and peptidoglycan. In bacteria, the functional significance of the involvement of multiple LysM domains in substrate binding has so far lacked support from high-resolution structures of ligand-bound complexes. Here, a structural study of the Thermus thermophilus NlpC/P60 endopeptidase containing two LysM domains is presented. The crystal structure and small-angle X-ray scattering solution studies of this endopeptidase revealed the presence of a homodimer. The structure of the two LysM domains co-crystallized with N-acetyl-chitohexaose revealed a new intermolecular binding mode that may explain the differential interaction between LysM domains and short or long chitin oligomers. By combining the structural information with the three-dimensional model of peptidoglycan, a model suggesting how protein dimerization enhances the recognition of peptidoglycan is proposed.

  9. Mechanisms of Involvement of Eicosanoids and their Precursors in the Pathophysiology and Treatment of Schizophrenia.

    Science.gov (United States)

    Schmidt, Luise; Ceglarek, Uta; Kortz, Linda; Hoop, Marcus; Kirkby, Kenneth Clifford; Thiery, Joachim; Himmerich, Hubertus

    2013-09-01

    The pathophysiology of schizophrenia has not been fully elucidated but there are converging leads to understanding this complex psychiatric disorder. One family of molecules that may play a crucial role in the development of schizophrenia is the eicosanoids. Review of the literature on eicosanoids in patients with schizophrenia points to findings in three areas: precursor molecules such as polyunsaturated fatty acids (PUFAs) and specifically arachidonic acid (AA), the actions of specific eicosanoids such as thromboxane A2 (TxA2), thromboxane B2 (TxB2) and prostaglandin E2 (PGE2), and enzymes with important functions in eicosanoid metabolism such as cyclooxygenase 2 (COX-2). It has also been found that classical as well as second generation antipsychotics, drugs used to treat schizophrenia, influence eicosanoid metabolism. For example, clozapine and its metabolite N-desmethylclozapine (NDMC) decreased TxB2 production in vitro. Eicosanoids and the enzymes involved in their metabolism may provide novel future drug targets. Therapeutic response to COX-2 inhibitors has already been demonstrated in patients at an early stage of schizophrenia. COX-2 inhibitors may exert this therapeutic action through their effects in reducing PGE2, type-2 cytokine and kynurenic acid production and strengthening glutamatergic neurotransmission.

  10. Modelling and pathway identification involving the transport mechanism of a complex metabolic system in batch culture

    Science.gov (United States)

    Yuan, Jinlong; Zhang, Xu; Zhu, Xi; Feng, Enmin; Yin, Hongchao; Xiu, Zhilong

    2014-06-01

    The bio-dissimilation of glycerol to 1,3-propanediol (1,3-PD) by Klebsiella pneumoniae (K. pneumoniae) can be characterized by a complex metabolic system of interactions among biochemical fluxes, metabolic compounds, key enzymes and genetic regulation. In this paper, in consideration of the fact that the transport ways of 1,3-PD and glycerol with different weights across cell membrane are still unclear in batch culture, we consider 121 possible metabolic pathways and establish a novel mathematical model which is represented by a complex metabolic system. Taking into account the difficulty in accurately measuring the concentration of intracellular substances and the absence of equilibrium point for the metabolic system of batch culture, the novel approach used here is to define quantitatively biological robustness of the intracellular substance concentrations for the overall process of batch culture. To determine the most possible metabolic pathway, we take the defined biological robustness as cost function and establish an identification model, in which 1452 system parameters and 484 pathway parameters are involved. Simultaneously, the identification model is subject to the metabolic system, continuous state constraints and parameter constraints. As such, solving the identification model by a serial program is a very complicated task. We propose a parallel migration particle swarm optimization algorithm (MPSO) capable of solving the identification model in conjunction with the constraint transcription and smoothing approximation techniques. Numerical results show that the most possible metabolic pathway and the corresponding metabolic system can reasonably describe the process of batch culture.

  11. Mechanism of cancer drug resistance and the involvement of noncoding RNAs.

    Science.gov (United States)

    Xia, Hongping; Hui, Kam M

    2014-01-01

    Drug resistance is one of the major reasons for the failure of cancer therapies. Although our understanding of resistance to targeted cancer drugs remains incomplete, new and more creative approaches are being exploited to intercept this phenomenon. Considerable advances have been made in our understanding that cancer drug resistance can be caused by alterations of drug efflux, increases in drug metabolism, mutations of drug targets, alterations in DNA repair and cell cycle, changes in cell apoptosis and autophagy, induction of epithelial-mesenchymal transition (EMT) and the generation of cancer stem cells (CSCs). Furthermore, intracellular signalling pathways have been shown to play key physiological roles and the abnormal activation of signalling pathways may be correlated with drug resistance. Recently, noncoding RNAs (ncRNAs), including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), have emerged as important regulators of gene expression and alternative splicing, which provides cells with yet another mode to greatly increase regulatory complexity and fine-tune their transcriptome and can rapidly adjust their proteome in response to stimuli. Consequently, a wide variety of biological functions have been shown to depend on the coordinated interactions between noncoding RNAs and cellular signalling networks to achieve a concerted desired physiological outcome, whereas mutations and dysregulation of ncRNAs have been linked to diverse human diseases, including cancer drug resistance. In this review, we will discuss recent findings on the multiple molecular roles of regulatory ncRNAs on the signalling pathways involved in cancer drug resistance and the therapeutic potential of reverse drug resistance.

  12. Paracrine mechanisms involved in the control of early stages of mammalian spermatogenesis

    Directory of Open Access Journals (Sweden)

    Pellegrino eRossi

    2013-11-01

    Full Text Available Within the testis, Sertoli cell is the primary target of pituitary FSH. Several growth factors have been described to be produced specifically by Sertoli cells and modulate male germ cell development through paracrine mechanisms. Some have been shown to act directly on spermatogonia such as GDNF, which acts on self-renewal of spermatogonial stem cells (SSCs while inhibiting their differentiation; BMP4, which has both a proliferative and differentiative effect on these cells, and KL, which stimulates the KIT tyrosine-kinase receptor expressed by differentiating spermatogonia (but not by SSCs. KL not only controls the proliferative cycles of KIT positive spermatogonia, but it also stimulates the expression of genes that are specific of the early phases of meiosis, whereas the expression of typical spermatogonial markers is down-regulated. On the contrary, FGF9 acts as a meiotic inhibiting substance both in fetal gonocytes and in post-natal spermatogonia through the induction of the RNA-binding protein NANOS2. Vitamin A, which is metabolized to Retinoic Acid in Sertoli cells, controls both SSCs differentiation through KIT induction and NANOS2 inhibition, and meiotic entry of differentiating spermatogonia through STRA8 upregulation.

  13. Involvement of a joker mutation in a polymerase-independent lethal mutagenesis escape mechanism.

    Science.gov (United States)

    Agudo, Rubén; de la Higuera, Ignacio; Arias, Armando; Grande-Pérez, Ana; Domingo, Esteban

    2016-07-01

    We previously characterized a foot-and-mouth disease virus (FMDV) with three amino acid replacements in its polymerase (3D) that conferred resistance to the mutagenic nucleoside analogue ribavirin. Here we show that passage of this mutant in the presence of high ribavirin concentrations resulted in selection of viruses with the additional replacement I248T in 2C. This 2C substitution alone (even in the absence of replacements in 3D) increased FMDV fitness mainly in the presence of ribavirin, prevented an incorporation bias in favor of A and U associated with ribavirin mutagenesis, and conferred the ATPase activity of 2C decreased sensitivity to ribavirin-triphosphate. Since in previous studies we described that 2C with I248T was selected under different selective pressures, this replacement qualifies as a joker substitution in FMDV evolution. The results have identified a role of 2C in nucleotide incorporation, and have unveiled a new polymerase-independent mechanism of virus escape to lethal mutagenesis.

  14. Auxin-induced growth of Avena coleoptiles involves two mechanisms with different pH optima

    Science.gov (United States)

    Cleland, R. E.

    1992-01-01

    Although rapid auxin-induced growth of coleoptile sections can persist for at least 18 hours, acid-induced growth lasts for a much shorter period of time. Three theories have been proposed to explain this difference in persistence. To distinguish between these theories, the pH dependence for auxin-induced growth of oat (Avena sativa L.) coleoptiles has been determined early and late in the elongation process. Coleoptile sections from which the outer epidermis was removed to facilitate buffer entry were incubated, with or without 10 micromolar indoleacetic acid, in 20 millimolar buffers at pH 4.5 to 7.0 to maintain a fixed wall pH. During the first 1 to 2 hours after addition of auxin, elongation occurs by acid-induced extension (i.e. the pH optimum is <5 and the elongation varies inversely with the solution pH). Auxin causes no additional elongation because the buffers prevent further changes in wall pH. After 60 to 90 minutes, a second mechanism of auxin-induced growth, whose pH optimum is 5.5 to 6.0, predominates. It is proposed that rapid growth responses to changes in auxin concentration are mediated by auxin-induced changes in wall pH, whereas the prolonged, steady-state growth rate is controlled by a second, auxin-mediated process whose pH optimum is less acidic.

  15. Endocannabinoids are involved in male vertebrate reproduction: regulatory mechanisms at central and gonadal level

    Directory of Open Access Journals (Sweden)

    Patrizia eBovolin

    2014-04-01

    Full Text Available Endocannabinoids are natural lipids regulating a large array of physiological functions and behaviors in vertebrates. The endocannabinoid system is highly conserved in evolution and comprises several specific receptors (type-1 and type-2 cannabinoid receptors, their endogenous ligands (e.g. anandamide and 2-arachidonoylglycerol, and a number of biosynthetic and degradative enzymes. In the last few years, endocannabinoids have been described as critical signals in the control of male and female reproduction at multiple levels: centrally, by targeting hypothalamic Gonadotropin-Releasing-Hormone secreting neurons and pituitary, and locally, with direct effects on the gonads. These functions are supported by the extensive localization of cannabinoid receptors and endocannabinoid metabolic enzymes at different levels of the hypothalamic-pituitary-gonadal axis in mammals, as well as bonyfish and amphibians. In vivo and in vitro studies indicate that endocannabinoids centrally regulate gonadal functions by modulating the Gonadotropin Releasing Hormone-gonadotropin-steroid network through direct and indirect mechanisms. Several proofs of local endocannabinoid regulation have been found in the testis and male genital tracts, since endocannabinoids control Sertoli and Leydig cells activity, germ cell progression, as well as the acquisition of sperm functions. A comparative approach usually is a key step in the study of physiological events leading to the building of a general model. Thus, in this review we summarize the action of endocannabinoids at different levels of the male reproductive axis, with special emphasis, where appropriate, on data from non-mammalian vertebrates.

  16. Kindling-induced learning deficiency and possible cellular and molecular involved mechanisms.

    Science.gov (United States)

    Sherafat, Mohammad Amin; Ronaghi, Abdolaziz; Ahmad-Molaei, Leila; Nejadhoseynian, Mohammad; Ghasemi, Rasoul; Hosseini, Arman; Naderi, Nima; Motamedi, Fereshteh

    2013-06-01

    Hippocampus learning disturbance is a major symptom of patients with seizure, hence hippocampal dysfunction has essential role in worsening the disease. Hippocampal formation includes neurons and myelinated fibers that are necessary for acquisition and consolidation of memory, long-term potentiation and learning activity. The exact mechanism by which seizure can decrease memory and learning activity of hippocampus remains unknown. In the present study, electrical kindling-induced learning deficit in rats was evaluated by Morris water maze (MWM) test. The hippocampus was removed and changes in neurons and myelin sheaths around hippocampal fibers were investigated using histological and immunohistochemical methods. Demyelination was assessed by luxol fast blue staining, and immunohistological staining of myelin-binding protein (MBP). The TUNEL assay was used for evaluation of neuronal apoptosis and the glial fibriliary acetic protein (GFAP) was used for assessment of inflammatory reaction. The results indicated that electrical kindling of hippocampus could induce deficiency in spatial learning and memory as compared to control group. In addition, electrical kindling caused damage to the myelin sheath around hippocampal fibers and produced vast demyelination. Furthermore, an increase in the number of apoptotic cells in hippocampal slices was observed. In addition, inflammatory response was higher in kindled animals as compared to the control group. The results suggested that the decrease in learning and memory in kindled animals is likely due to demyelination and augmentation in apoptosis rate accompanied by inflammatory reaction in hippocampal neurons of kindled rats.

  17. Auxin-induced growth of Avena coleoptiles involves two mechanisms with different pH optima

    Science.gov (United States)

    Cleland, R. E.

    1992-01-01

    Although rapid auxin-induced growth of coleoptile sections can persist for at least 18 hours, acid-induced growth lasts for a much shorter period of time. Three theories have been proposed to explain this difference in persistence. To distinguish between these theories, the pH dependence for auxin-induced growth of oat (Avena sativa L.) coleoptiles has been determined early and late in the elongation process. Coleoptile sections from which the outer epidermis was removed to facilitate buffer entry were incubated, with or without 10 micromolar indoleacetic acid, in 20 millimolar buffers at pH 4.5 to 7.0 to maintain a fixed wall pH. During the first 1 to 2 hours after addition of auxin, elongation occurs by acid-induced extension (i.e. the pH optimum is Auxin causes no additional elongation because the buffers prevent further changes in wall pH. After 60 to 90 minutes, a second mechanism of auxin-induced growth, whose pH optimum is 5.5 to 6.0, predominates. It is proposed that rapid growth responses to changes in auxin concentration are mediated by auxin-induced changes in wall pH, whereas the prolonged, steady-state growth rate is controlled by a second, auxin-mediated process whose pH optimum is less acidic.

  18. A POTENTIAL MECHANISM OF BREAKTHROUGH BLEEDING ASSOCIATED WITH PROGESTIN: INVOLVEMENT IN ALTERATION OF ENDOMETRIAL ENDOTHELIAL CELLS

    Institute of Scientific and Technical Information of China (English)

    Gui-hua Sha; Shou-qing Lin

    2008-01-01

    Objective To explore the potential mechanism of breakthrough bleeding associated with progestin with in vitro methods.Methods The isolation and culture of human endometrial endothelial cells (HEECs) was performed with themethod established in our laboratory. The content and activity of urokinase-type plasminogen activator (uPA) and the content of plasminogen activator inhibitor-1 ( PAI-1 ) in cell supernatants after incubated with different concentrations of progesterone (0-5 μmol/L) and 17β-estradiol (0, 0.1, or 1 nmol/L) were measured by method of ELISA. Apoptosis rate of HEECs was measured by flow eytometry. Viable cell count was measured by MTr.Results The increased level of progesterone (0.5-5 μmol/L) combined with 17β-estmdiol elevated content and activity of uPA while the production of PAI-1 remained unchanged. The apoptosis of HEECs was inhibited along with the increment of total viable cell counts at higher ooneenwations of progesterone with 17β-estradiol.Conclusion The inhibition of apoptosis and increased content and activity of uPA may contribute to the occurrence of irregular bleeding associated with progestin use to some extent.

  19. Adaptation of grapevine flowers to cold involves different mechanisms depending on stress intensity.

    Directory of Open Access Journals (Sweden)

    Mélodie Sawicki

    Full Text Available Grapevine flower development and fruit set are influenced by cold nights in the vineyard. To investigate the impact of cold stress on carbon metabolism in the inflorescence, we exposed the inflorescences of fruiting cuttings to chilling and freezing temperatures overnight and measured fluctuations in photosynthesis and sugar content. Whatever the temperature, after the stress treatment photosynthesis was modified in the inflorescence, but the nature of the alteration depended on the intensity of the cold stress. At 4°C, photosynthesis in the inflorescence was impaired through non-stomatal limitations, whereas at 0°C it was affected through stomatal limitations. A freezing night (-3°C severely deregulated photosynthesis in the inflorescence, acting primarily on photosystem II. Cold nights also induced accumulation of sugars. Soluble carbohydrates increased in inflorescences exposed to -3°C, 0°C and 4°C, but starch accumulated only in inflorescences of plants treated at 0 and -3°C. These results suggest that inflorescences are able to cope with cold temperatures by adapting their carbohydrate metabolism using mechanisms that are differentially induced according to stress intensity.

  20. Effects of nitric oxide on magnocellular neurons of the supraoptic nucleus involve multiple mechanisms.

    Science.gov (United States)

    Silva, M P da; Cedraz-Mercez, P L; Varanda, W A

    2014-02-01

    Physiological evidence indicates that the supraoptic nucleus (SON) is an important region for integrating information related to homeostasis of body fluids. Located bilaterally to the optic chiasm, this nucleus is composed of magnocellular neurosecretory cells (MNCs) responsible for the synthesis and release of vasopressin and oxytocin to the neurohypophysis. At the cellular level, the control of vasopressin and oxytocin release is directly linked to the firing frequency of MNCs. In general, we can say that the excitability of these cells can be controlled via two distinct mechanisms: 1) the intrinsic membrane properties of the MNCs themselves and 2) synaptic input from circumventricular organs that contain osmosensitive neurons. It has also been demonstrated that MNCs are sensitive to osmotic stimuli in the physiological range. Therefore, the study of their intrinsic membrane properties became imperative to explain the osmosensitivity of MNCs. In addition to this, the discovery that several neurotransmitters and neuropeptides can modulate their electrical activity greatly increased our knowledge about the role played by the MNCs in fluid homeostasis. In particular, nitric oxide (NO) may be an important player in fluid balance homeostasis, because it has been demonstrated that the enzyme responsible for its production has an increased activity following a hypertonic stimulation of the system. At the cellular level, NO has been shown to change the electrical excitability of MNCs. Therefore, in this review, we focus on some important points concerning nitrergic modulation of the neuroendocrine system, particularly the effects of NO on the SON.

  1. The Ras/Raf/MEK/extracellular signal-regulated kinase pathway induces autocrine-paracrine growth inhibition via the leukemia inhibitory factor/JAK/STAT pathway.

    Science.gov (United States)

    Park, Jong-In; Strock, Christopher J; Ball, Douglas W; Nelkin, Barry D

    2003-01-01

    Sustained activation of the Ras/Raf/MEK/extracellular signal-regulated kinase (ERK) pathway can lead to cell cycle arrest in many cell types. We have found, with human medullary thyroid cancer (MTC) cells, that activated Ras or c-Raf-1 can induce growth arrest by producing and secreting an autocrine-paracrine factor. This protein was purified from cell culture medium conditioned by Raf-activated MTC cells and was identified by mass spectrometry as leukemia inhibitory factor (LIF). LIF expression upon Raf activation and subsequent activation of JAK-STAT3 was also observed in small cell lung carcinoma cells, suggesting that this autocrine-paracrine signaling may be a common response to Ras/Raf activation. LIF was sufficient to induce growth arrest and differentiation of MTC cells. This effect was mediated through the gp130/JAK/STAT3 pathway, since anti-gp130 blocking antibody or dominant-negative STAT3 blocked the effects of LIF. Thus, LIF expression provides a novel mechanism allowing Ras/Raf signaling to activate the JAK-STAT3 pathway. In addition to this cell-extrinsic growth inhibitory pathway, we find that the Ras/Raf/MEK/ERK pathway induces an intracellular growth inhibitory signal, independent of the LIF/JAK/STAT3 pathway. Therefore, activation of the Ras/Raf/MEK/ERK pathway can lead to growth arrest and differentiation via at least two different signaling pathways. This use of multiple pathways may be important for "fail-safe" induction and maintenance of cell cycle arrest.

  2. Autocrine production of beta-chemokines protects CMV-Specific CD4 T cells from HIV infection.

    Directory of Open Access Journals (Sweden)

    Joseph P Casazza

    2009-10-01

    Full Text Available Induction of a functional subset of HIV-specific CD4+ T cells that is resistant to HIV infection could enhance immune protection and decrease the rate of HIV disease progression. CMV-specific CD4+ T cells, which are less frequently infected than HIV-specific CD4+ T cells, are a model for such an effect. To determine the mechanism of this protection, we compared the functional response of HIV gag-specific and CMV pp65-specific CD4+ T cells in individuals co-infected with CMV and HIV. We found that CMV-specific CD4+ T cells rapidly up-regulated production of MIP-1alpha and MIP-1beta mRNA, resulting in a rapid increase in production of MIP-1alpha and MIP-1beta after cognate antigen stimulation. Production of beta-chemokines was associated with maturational phenotype and was rarely seen in HIV-specific CD4+ T cells. To test whether production of beta-chemokines by CD4+ T cells lowers their susceptibility to HIV infection, we measured cell-associated Gag DNA to assess the in vivo infection history of CMV-specific CD4+ T cells. We found that CMV-specific CD4+ T cells which produced MIP-1beta contained 10 times less Gag DNA than did those which failed to produce MIP-1beta. These data suggest that CD4+ T cells which produce MIP-1alpha and MIP-1beta bind these chemokines in an autocrine fashion which decreases the risk of in vivo HIV infection.

  3. 'Big'-insulin-like growth factor-II signaling is an autocrine survival pathway in gastrointestinal stromal tumors.

    NARCIS (Netherlands)

    Rikhof, B.; Graaf, W.T.A. van der; Suurmeijer, A.J.H.; Doorn, J. van; Meersma, G.J.; Groenen, P.J.T.A.; Schuuring, E.M.; Meijer, C.; Jong, S. de

    2012-01-01

    New treatment targets need to be identified in gastrointestinal stromal tumors (GISTs) to extend the treatment options for patients experiencing failure with small-molecule tyrosine kinase inhibitors, such as imatinib. Insulin-like growth factor (IGF)-II acts as an autocrine factor in several tumor

  4. Mechanisms involved in the association between periodontitis and complications in pregnancy.

    Directory of Open Access Journals (Sweden)

    Marcela eYang

    2015-01-01

    Full Text Available The association between periodontitis and gestation complications such as premature delivery, low weight at birth and preeclampsia has been suggested. Nevertheless, epidemiological data have shown contradictory data, mainly due to differences in clinical parameters of periodontitis assessment. Furthermore, differences in microbial composition and immune response between aggressive and chronic periodontitis are not addressed by these epidemiological studies. We aimed to review the current data on the association between gestation complications and periodontitis, and the mechanisms underlying this association. Shifts in the microbial composition of the subgingival biofilm may occur during pregnancy, leading to a potentially more hazardous microbial community. Pregnancy is characterized by physiological immune tolerance. However, the infection leads to a shift in maternal immune response to a pathogenic pro-inflammatory response, with production of inflammatory cytokines and toxic products. In women with periodontitis, the infected periodontal tissues may act as reservoirs of bacteria and their products which can disseminate to the fetus-placenta unit. In severe periodontitis patients, the infection agents and their products are able to activate inflammatory signaling pathways locally and in extra-oral sites, including the placenta-fetal unit, which may not only induce preterm labor, but also lead to preeclampsia and restrict intrauterine growth. Despite these evidences, the effectiveness of periodontal treatment in preventing gestational complications was still not established since it may be influenced by several factors such as severity of disease, composition of microbial community, treatment strategy, and period of treatment throughout pregnancy. This lack of scientific evidence does not exclude the need to control infection and inflammation in periodontitis patients during pregnancy, and treatment protocols should be validated.

  5. Mechanisms Involved in Thromboxane A2 -induced Vasoconstriction of Rat Intracavernous Small Penile Arteries.

    Science.gov (United States)

    Grann, Martin; Comerma-Steffensen, Simon; Arcanjo, Daniel D R; Simonsen, Ulf

    2016-10-01

    Diabetes is associated with erectile dysfunction and with hypercontractility in erectile tissue and this is in part ascribed to increased formation of thromboxane. Rho kinase (ROCK) is a key regulator of calcium sensitization and contraction in vascular smooth muscle. This study investigated the role of calcium and ROCK in contraction evoked by activation of the thromboxane receptors. Rat intracavernous penile arteries were mounted for isometric tension and intracellular calcium ([Ca(2+) ]i ) recording and corpus cavernosum for measurements of MYPT1 phosphorylation. In penile arteries, U46619 by activation of thromboxane receptors concentration dependently increased calcium and contraction. U46619-induced calcium influx was blocked by nifedipine, a blocker of L-type calcium channels, and by 2-aminoethoxydiphenyl borate, a blocker of transient receptor potential (TRP) channels. Inhibitors of ROCK, Y27632 and glycyl-H1152P, concentration dependently reduced U46619-induced contraction, but only Y27632 reduced [Ca(2+) ]i levels in the penile arteries activated with either high extracellular potassium or U46619. MYPT-Thr(850) phosphorylation in corpus cavernous strips was increased in response to U46619 through activation of TP receptors and was found to be a direct result of phosphorylation by ROCK. Y27632 induced less relaxation in mesenteric arteries, H1152P induced equipotent relaxations, and a protein kinase C inhibitor, Ro-318220, failed to relax intracavernous penile arteries, but induced full relaxation in rat mesenteric arteries. Our findings suggest that U46619 contraction depends on Ca(2+) influx through L-type and TRP channels, and ROCK-dependent mechanisms in penile arteries. Inhibition of the ROCK pathway is a potential approach for the treatment of erectile dysfunction associated with hypertension and diabetes.

  6. Study of catalase adsorption on two mixed-mode ligands and the mechanism involved therein.

    Science.gov (United States)

    Shiva Ranjini, S; Vijayalakshmi, M A

    2012-11-01

    Mixed-mode chromatography sorbents n-hexylamine HyperCel™ (HEA) and phenylpropylamine HyperCel™ (PPA) were evaluated for the study of adsorption of catalase from two different sources. Various parameters such as buffer composition, ionic strength and pH were investigated to study the mechanism of interaction of commercially available pre-purified catalase from Bovine liver, purified catalase from black gram (Vigna mungo) and crude extract of black gram containing catalase with these mixed-mode ligands. A simple and economical screening protocol for identifying optimal buffer conditions for adsorption and desorption of catalase was established with micro volumes of the sorbent in batch mode. With HEA HyperCel, it was observed that pre-purified catalase from both bovine liver and black gram was completely retained at pH 7.0, irrespective of the presence or absence of NaCl in the adsorption buffer, whereas the catalase from crude extract of black gram was completely retained only in the presence of 0.2 M salt in the adsorption buffer. The elution of catalase from both the sources was accomplished by lowering the pH to 4.5 in absence of salt. In case of PPA HyperCel, catalase from both the sources was very strongly adsorbed under different buffer conditions studied, and elution did not yield a significant catalase activity. From the screening experiments, it could be concluded that the interaction of catalase with HEA HyperCel could be dominated by hydrophobic forces with minor contributions from ionic interaction and with PPA HyperCel, it could be a combination of different non-covalent interactions acting on different loci on the surface of the protein.

  7. Mechanisms Involved in the Association between Periodontitis and Complications in Pregnancy

    Science.gov (United States)

    Zi, Marcela Yang Hui; Longo, Priscila Larcher; Bueno-Silva, Bruno; Mayer, Marcia Pinto Alves

    2015-01-01

    The association between periodontitis and some of the problems with pregnancy such as premature delivery, low weight at birth, and preeclampsia (PE) has been suggested. Nevertheless, epidemiological data have shown contradictory data, mainly due to differences in clinical parameters of periodontitis assessment. Furthermore, differences in microbial composition and immune response between aggressive and chronic periodontitis are not addressed by these epidemiological studies. We aimed to review the current data on the association between some of these problems with pregnancy and periodontitis, and the mechanisms underlying this association. Shifts in the microbial composition of the subgingival biofilm may occur during pregnancy, leading to a potentially more hazardous microbial community. Pregnancy is characterized by physiological immune tolerance. However, the infection leads to a shift in maternal immune response to a pathogenic pro-inflammatory response, with production of inflammatory cytokines and toxic products. In women with periodontitis, the infected periodontal tissues may act as reservoirs of bacteria and their products that can disseminate to the fetus-placenta unit. In severe periodontitis patients, the infection agents and their products are able to activate inflammatory signaling pathways locally and in extra-oral sites, including the placenta-fetal unit, which may not only induce preterm labor but also lead to PE and restrict intrauterine growth. Despite these evidences, the effectiveness of periodontal treatment in preventing gestational complications was still not established since it may be influenced by several factors such as severity of disease, composition of microbial community, treatment strategy, and period of treatment throughout pregnancy. This lack of scientific evidence does not exclude the need to control infection and inflammation in periodontitis patients during pregnancy, and treatment protocols should be validated. PMID:25688342

  8. Nephropathy and hepatopathy in weaned piglets provoked by natural ochratoxin A and involved mechanisms.

    Science.gov (United States)

    Zhang, Zheqian; Gan, Fang; Xue, Hongxia; Liu, Yunhuan; Huang, Da; Khan, Alam Zeb; Chen, Xingxiang; Huang, Kehe

    2016-04-01

    Ochratoxin A (OTA) contamination is a worldwide problem in pig industry. The objectives of the present study were to investigate the toxicity of natural OTA in weaned piglets and to further explore the underlying mechanisms. Totally, 36 crossbred ([Landrace × Yorkshire] × Duroc) piglets were randomly divided into 3 groups (three replicates per group, 4 piglets per replicate), and fed a basal diet (Con group) and basal diets added with 0.4 mg (OTA-L group) or 0.8 mg OTA/kg (OTA-H group), respectively for 42 days. The results showed that growth performance was significantly decreased (P<0.05) in OTA added groups compared with Con group. OTA concentration was relatively high in serum and OTA concentration in kidney was higher than in liver, respectively. AST, creatinine and urea in serum of OTA added groups were significantly increased (P<0.05), while glucose, total protein, albumin and globulin in serum of OTA added groups were significantly decreased (P<0.05) compared with Con group. Degenerative changes were observed in the epithelial cells of proximal tubules and in hepatocytes of OTA added groups. Antioxidant capacities in blood of OTA added groups and in kidney of OTA-H group were significantly decreased (P<0.05) compared with Con group. The mRNA expressions of bcl-2 were up-regulated, mRNA expressions of bax were down-regulated and the ratio of bcl-2 and bax was increased in kidney and liver of OTA added groups compared with Con group. In conclusion, OTA could reduce antioxidant capacity and suppress apoptosis in tissues and cause degenerative changes in the epithelial cells in proximal tubules and hepatic cells, which may have a negative effect on the growth performance of piglets.

  9. The Vulnerability of Vessels Involved in the Role of Embolism and Hypoperfusion in the Mechanisms of Ischemic Cerebrovascular Diseases

    Directory of Open Access Journals (Sweden)

    Yong Peng Yu

    2016-01-01

    Full Text Available Accurate definition and better understanding of the mechanisms of stroke are crucial as this will guide the effective care and therapy. In this paper, we review the previous basic and clinical researches on the causes or mechanisms of ischemic cerebrovascular diseases (ICVD and interpret the correlation between embolism and hypoperfusion based on vascular stenosis and arterial intimal lesions. It was suggested that if there is no embolus (dynamic or in situ emboli, there might be no cerebral infarction. Three kinds of different clinical outcomes of TIA were theoretically interpreted based on its mechanisms. We suppose that there is a correlation between embolism and hypoperfusion, and which mechanisms (hypoperfusion or hypoperfusion induced microemboli playing the dominant role in each type of ICVD depends on the unique background of arterial intimal lesions (the vulnerability of vessels. That is to say, the vulnerability of vessels is involved in the role of embolism and hypoperfusion in the mechanisms of ischemic cerebrovascular diseases. This inference might enrich and provide better understandings for the underlying etiologies of ischemic cerebrovascular events.

  10. 涉诉信访终结机制研究%Research on Mechanism of Settling Petition Involving Lawsuit

    Institute of Scientific and Technical Information of China (English)

    宋春龙; 徐琦

    2012-01-01

    Mechanism of settling petition involving lawsuit is an important part to the system of solving of China. Due to problems in the practice, it's necessary to establish a complete system of As the first step on the ladder to the system of petition involving lawsuit, the mechanism of settling dispute re- this field. petition in- volving lawsuit needs to be systematized based on theories. Courts of each level have come up with different petition settling mechanisms, which can be served as practical support to the integration and improvement of this system.%涉诉信访制度是我国多元化解纷机制的重要组成部分,由于在实践中所存在的问题,有必要对其进行完整的制度构建。涉诉信访的终结机制作为打开涉诉信访制度的突破口,亟须系统化、理论化的构建。各级法院在实践中也总结出了不同的终结机制,为整个制度的整合与完整提供了实践支持。

  11. Reevaluation of the proposed autocrine proliferative function of prolactin in breast cancer

    DEFF Research Database (Denmark)

    Nitze, Louise Maymann; Galsgaard, Elisabeth Douglas; Din, Nanni

    2013-01-01

    synthesised PRL in breast cancer. We analysed the expression of PRL in human breast cancer tumours using qPCR analysis and in situ hybridization (ISH). PRL mRNA expression was very low or undetectable in the majority of samples in three cDNA arrays representing samples from 144 breast cancer patients...... and in 13 of 14 breast cancer cell lines when analysed by qPCR. In accordance, PRL expression did not reach detectable levels in any of the 19 human breast carcinomas or 5 cell lines, which were analysed using a validated ISH protocol. Two T47D-derived breast cancer cell lines were stably transfected......The pituitary hormone prolactin (PRL) has been implicated in tumourigenesis. Expression of PRL and its receptor (PRLR) was reported in human breast epithelium and breast cancer cells. It was suggested that PRL may act as an autocrine/paracrine growth factor. Here, we addressed the role of locally...

  12. Identification and targeting of a TACE-dependent autocrine loopwhich predicts poor prognosis in breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kenny, Paraic A.; Bissell, Mina J.

    2005-06-15

    The ability to proliferate independently of signals from other cell types is a fundamental characteristic of tumor cells. Using a 3D culture model of human breast cancer progression, we have delineated a protease-dependent autocrine loop which provides an oncogenic stimulus in the absence of proto-oncogene mutation. Inhibition of this protease, TACE/ADAM17, reverts the malignant phenotype by preventing mobilization of two crucial growth factors, Amphiregulin and TGF{alpha}. We show further that the efficacy of EGFR inhibitors is overcome by physiological levels of growth factors and that successful EGFR inhibition is dependent on reducing ligand bioavailability. Using existing patient outcome data, we demonstrate a strong correlation between TACE and TGF{alpha} expression in human breast cancers that is predictive of poor prognosis.

  13. Purification of autocrine growth factor from conditioned medium of rat sarcoma (XC) cells.

    Science.gov (United States)

    Checiówna, D; Klein, A

    1996-01-01

    Transformation of rat cells by Rous sarcoma virus(es) induced the release of growth factors into serum-free conditioned media. An PR-RSV-transformed rat cell line, XC, produced and released polypeptide factors which promote anchorage-dependent and anchorage-independent growth of XC cells. One of the autocrine factors of XC cells was purified to homogeneity by four-step procedure: ultrafiltration, ion-exchange chromatography on MonoS, reverse-phase chromatography on Spherisorb ODS2 and gel filtration on Superose 12. The factor gave a single band on SDS-electrophoresis on polyacrylamide gel and was assumed to have a molecular weight of 16 kDa. The factor is a potent mitogen for XC cells; half-maximal stimulation of DNA synthesis was achieved at a concentration of 0.8 ng/ml. The peptide is probably one of the family of EGF-like heparin-binding growth factors.

  14. MYC translocation-negative classical Burkitt lymphoma cases: an alternative pathogenetic mechanism involving miRNA deregulation

    DEFF Research Database (Denmark)

    Leucci, E; Cocco, M; Onnis, A

    2008-01-01

    at the standardization of FISH procedures in lymphoma diagnosis, we found that five cases out of 35 classic endemic BLs were negative for MYC translocations by using a split-signal as well as a dual-fusion probe. Here we investigated the expression pattern of miRNAs predicted to target c-Myc, in BL cases, to clarify...... whether alternative pathogenetic mechanisms may be responsible for lymphomagenesis in cases lacking the MYC translocation. miRNAs are a class of small RNAs that are able to regulate gene expression at the post-transcriptional level. Several studies have reported their involvement in cancer...

  15. Arbuscular Mycorrhizal Fungi for the Biocontrol of Plant-Parasitic Nematodes: A Review of the Mechanisms Involved.

    Science.gov (United States)

    Schouteden, Nele; De Waele, Dirk; Panis, Bart; Vos, Christine M

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) are obligate root symbionts that can protect their host plant against biotic stress factors such as plant-parasitic nematode (PPN) infection. PPN consist of a wide range of species with different life styles that can cause major damage in many important crops worldwide. Various mechanisms have been proposed to play a role in the biocontrol effect of AMF against PPN. This review presents an overview of the different mechanisms that have been proposed, and discusses into more detail the plausibility of their involvement in the biocontrol against PPN specifically. The proposed mechanisms include enhanced plant tolerance, direct competition for nutrients and space, induced systemic resistance (ISR) and altered rhizosphere interactions. Recent studies have emphasized the importance of ISR in biocontrol and are increasingly placing rhizosphere effects on the foreground as well, both of which will be the focal point of this review. Though AMF are not yet widely used in conventional agriculture, recent data help to develop a better insight into the modes of action, which will eventually lead toward future field applications of AMF against PPN. The scientific community has entered an exciting era that provides the tools to actually unravel the underlying molecular mechanisms, making this a timely opportunity for a review of our current knowledge and the challenges ahead.

  16. Visual loss in HIV-associated cryptococcal meningitis: A case series and review of the mechanisms involved

    Directory of Open Access Journals (Sweden)

    Anand Moodley

    2015-04-01

    Full Text Available Permanent visual loss is a devastating yet preventable complication of cryptococcal meningitis. Early and aggressive management of cerebrospinal fluid pressure in conjunction with antifungal therapy is required. Historically, the mechanisms of visual loss in cryptococcal meningitis have included optic neuritis and papilloedema. Hence, the basis of visual loss therapy has been steroid therapy and intracranial pressure lowering without clear guidelines. With the use of high-resolution magnetic resonance imaging of the optic nerve, an additional mechanism has emerged, namely an optic nerve sheath compartment syndrome (ONSCS caused by severely elevated intracranial pressure and fungal loading in the peri-optic space. An improved understanding of these mechanisms and recognition of the important role played by raised intracranial pressure allows for more targeted treatment measures and better outcomes. In the present case series of 90 HIV co-infected patients with cryptococcal meningitis, we present the clinical and electrophysiological manifestations of Cryptococcus-induced visual loss and review the mechanisms involved.

  17. Enhancement of non-heme iron absorption by anchovy (Engraulis japonicus) muscle protein hydrolysate involves a nanoparticle-mediated mechanism.

    Science.gov (United States)

    Wu, Haohao; Zhu, Suqin; Zeng, Mingyong; Liu, Zunying; Dong, Shiyuan; Zhao, Yuanhui; Huang, Hai; Lo, Y Martin

    2014-08-27

    The mechanisms by which meat enhances human absorption of non-heme iron remain unknown. Recently, anchovy (Engraulis japonicus) muscle protein hydrolysate (AMPH) was found to mediate the formation of nanosized ferric hydrolysis products in vitro. The current paper evaluates the effects of AMPH on the bioavailability and the intestinal speciation of non-heme iron in rats, followed by an investigation of cellular uptake pathways of in vitro-formed AMPH-stabilized nanosized ferric hydrolysis products (ANPs) by polarized human intestinal epithelial (Caco-2) cells. The hemoglobin regeneration efficiencies in anemic rats followed the order ferric citrate (9.79 ± 2.02%) iron in the groups of FC+AMPH, FeSO4, and ANPs were significantly lower than the corresponding hemoglobin regeneration efficiencies (P iron in intestinal iron absorption from FC+AMPH, FeSO4, and ANPs. Calcein-fluorescence measurements of the labile iron pool of polarized Caco-2 cells revealed the involvement of both divalent transporter 1 and endocytosis in apical uptake of ANPs, with endocytosis dominating at acidic extracellular pH. Overall, AMPH enhancement of non-heme iron absorption involves a nanoparticle-mediated mechanism.

  18. On the Path of Election and Martyrdom: Some Psychic Mechanisms Involved in the Anders Behring Breivik's Determination as a Terrorist.

    Science.gov (United States)

    Cotti, Patricia

    2015-08-01

    On 22 July 2011, the Norwegian Anders Behring Breivik carried out two attacks in Oslo that cost the lives of 77 people, injured many others, and plunged the entire Norwegian nation into mourning. When he was arrested, Breivik presented himself as a member of the Knights Templar, whose mission is to defend the Christian Western world. He considers that he has sacrificed himself by his actions for his people and says that he has prepared himself for martyrdom. In analysing Breivik's words and writings, this article attempts to identify the thought mechanisms involved in Breivik's idea of election (megalomania) and martyrology. It highlights the importance of a mechanism of "return to the sender," whereby Breivik returns the reproaches directed at him by an agency of judgment (ego ideal or superegoic object). It emphasizes the existence of a "burning desire" and yearning (Sehnsucht) for this same persecuting superegoic object, an object that Breivik constantly wants to find again, even if in death. Taking into consideration Searles's hypothesis that the sense of being persecuted is a defence against the impossibility of mourning, and also H. Blum's hypothesis that persecutory feelings are indicative of fears of a "regressive loss of object constancy," the different psychic mechanisms and modes of functioning underlying Breivik's terrorist determination are related here to what we know about his affective development and infantile relationships.

  19. Identification of up-regulated proteins potentially involved in the antagonism mechanism of Bacillus amyloliquefaciens G1.

    Science.gov (United States)

    Cao, Haipeng; Zheng, Weidong; He, Shan; Wang, Hao; Wang, Tu; Lu, Liqun

    2013-06-01

    The use of Bacillus probiotics has been demonstrated as a promising method in the biocontrol of bacterial diseases in aquaculture. However, the molecular antibacterial mechanism of Bacillus still remains unclear. In order to explore the antibacterial mechanism of the potential antagonistic Bacillus amyloliquefaciens strain G1, comparative proteomics between B. amyloliquefaciens strain G1 and its non-antagonistic mutant strain was investigated. The 2-dimensional electrophoresis gel maps of their total extracted proteins were described and 42 different proteins were found to be highly expressed in strain G1 in comparison with those in the mutant strain. 35 of these up-regulated proteins were successfully identified using MALDI-TOF-TOF MS and databank analysis, and their biological functions were analyzed through the KEGG database. The increased expression of these proteins suggested that high levels of energy metabolism, biosynthesis and stress resistance could play important roles in strain G1's antagonism. To our knowledge, this is the first report on the proteins involved in the antagonism mechanism of B. amyloliquefaciens using a proteomic approach and the proteomic data also contribute to a better understanding of the molecular basis for the antagonism of B. amyloliquefaciens.

  20. Metal and metalloid foliar uptake by various plant species exposed to atmospheric industrial fallout: Mechanisms involved for lead

    Energy Technology Data Exchange (ETDEWEB)

    Schreck, E., E-mail: eva.schreck@ensat.fr [Universite de Toulouse (France); INP, UPS (France); EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement) (France); ENSAT, Avenue de l' Agrobiopole, 31326 Castanet Tolosan (France); CNRS (France); EcoLab, 31326 Castanet Tolosan (France); Foucault, Y. [Universite de Toulouse (France); INP, UPS (France); EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement) (France); ENSAT, Avenue de l' Agrobiopole, 31326 Castanet Tolosan (France); CNRS (France); EcoLab, 31326 Castanet Tolosan (France); STCM, Societe de Traitements Chimiques des Metaux, 30 Avenue de Fondeyre 31200 Toulouse (France); Sarret, G. [ISTerre (UMR 5275), Universite J. Fourier and CNRS, BP 53, 38041 Grenoble cedex 9 (France); Sobanska, S. [LASIR (UMR CNRS 8516), Universite de Lille 1, Bat. C5, 59655 Villeneuve d' Ascq cedex (France); Cecillon, L. [ISTerre (UMR 5275), Universite J. Fourier and CNRS, BP 53, 38041 Grenoble cedex 9 (France); Castrec-Rouelle, M. [Universite Pierre and Marie Curie (UPMC-Paris 6), Bioemco (Biogeochimie et Ecologie des Milieux Continentaux), Site Jussieu, Tour 56, 4 Place Jussieu, 75252 Paris cedex 05 (France); Uzu, G. [Laboratoire d' Aerologie (UMR 5560), OMP, UPS 14, Avenue Edouard Belin, 31400 Toulouse (France); GET (UMR 5563), IRD, 14, Avenue Edouard Belin, 31400 Toulouse (France); Dumat, C. [Universite de Toulouse (France); INP, UPS (France); EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement) (France); ENSAT, Avenue de l' Agrobiopole, 31326 Castanet Tolosan (France); CNRS (France); EcoLab, 31326 Castanet Tolosan (France)

    2012-06-15

    Fine and ultrafine metallic particulate matters (PMs) are emitted from metallurgic activities in peri-urban zones into the atmosphere and can be deposited in terrestrial ecosystems. The foliar transfer of metals and metalloids and their fate in plant leaves remain unclear, although this way of penetration may be a major contributor to the transfer of metals into plants. This study focused on the foliar uptake of various metals and metalloids from enriched PM (Cu, Zn, Cd, Sn, Sb, As, and especially lead (Pb)) resulting from the emissions of a battery-recycling factory. Metal and metalloid foliar uptake by various vegetable species, exhibiting different morphologies, use (food or fodder) and life-cycle (lettuce, parsley and rye-grass) were studied. The mechanisms involved in foliar metal transfer from atmospheric particulate matter fallout, using lead (Pb) as a model element was also investigated. Several complementary techniques (micro-X-ray fluorescence, scanning electron microscopy coupled with energy dispersive X-ray microanalysis and time-of-flight secondary ion mass spectrometry) were used to investigate the localization and the speciation of lead in their edible parts, i.e. leaves. The results showed lead-enriched PM on the surface of plant leaves. Biogeochemical transformations occurred on the leaf surfaces with the formation of lead secondary species (PbCO{sub 3} and organic Pb). Some compounds were internalized in their primary form (PbSO{sub 4}) underneath an organic layer. Internalization through the cuticle or penetration through stomata openings are proposed as two major mechanisms involved in foliar uptake of particulate matter. - Graphical abstract: Overall picture of performed observations and mechanisms potentially involved in lead foliar uptake. Highlights: Black-Right-Pointing-Pointer Foliar uptake of metallic particulate matter (PM) is of environmental and health concerns. Black-Right-Pointing-Pointer The leaf morphology influences the adsorption

  1. Resistance to coumaphos and diazinon in Boophilus microplus (Acari: Ixodidae) and evidence for the involvement of an oxidative detoxification mechanism.

    Science.gov (United States)

    Li, Andrew Y; Davey, Ronald B; Miller, Robert J; George, John E

    2003-07-01

    The levels of resistance to two organophosphate acaricides, coumaphos and diazinon, in several Mexican strains of Boophilus microplus (Canestrini) were evaluated using the FAO larval packet test. Regression analysis of LC50 data revealed a significant cross-resistance pattern between those two acaricides. Metabolic mechanisms of resistance were investigated with synergist bioassays. Piperonyl butoxide (PBO) reduced coumaphos toxicity in susceptible strains, but synergized coumaphos toxicity in resistant strains. There was a significant correlation between PBO synergism ratios and the coumaphos resistance ratios. The results suggest that an enhanced cytochrome P450 monooxygenase (cytP450)-mediated detoxification mechanism may exist in the resistant strains, in addition to the cytP450-mediated metabolic pathway that activates coumaphos. PBO failed to synergize diazinon toxicity in resistant strains, suggesting the cytP450 involved in detoxification were specific. Triphenylphosphate (TPP) synergized toxicity of both acaricides in both susceptible and resistant strains, and there was no correlation between TPP synergism ratios and the LC50 estimates for either acaricide. Esterases may not play a major role in resistance to coumaphos and diazinon in those strains. Bioassays with diethyl maleate (DEM) revealed a significant correlation between DEM synergism ratios and LC50 estimates for diazinon, suggesting a possible role for glutathione S-transferases in diazinon detoxification. Resistance to coumaphos in the Mexican strains of B. microplus was likely to be conferred by both a cytP450-mediated detoxification mechanism described here and the mechanism of insensitive acetylcholinesterases reported elsewhere. The results of this study also underscore the potential risk of coumaphos resistance in B. microplus from Mexico to the U.S. cattle fever tick eradication program.

  2. Mechanisms of a novel anticancer therapeutic strategy involving atmospheric pressure plasma-mediated apoptosis and DNA strand break formation.

    Science.gov (United States)

    Chung, Woo-Hyun

    2016-01-01

    Atmospheric pressure plasma has been developed for a variety of biomedical applications due to its chemically reactive components. Recently, the plasma has emerged as a promising novel cancer therapy based on its ability to selectively ablate cancer cells while leaving normal cells essentially unaffected. The therapeutic effect of plasma is attributed to intracellular generation of reactive oxygen/nitrogen species (ROS/RNS) leading to mitochondria-mediated apoptosis and to activation of the DNA damage checkpoint signaling pathway via severe DNA strand break formation. However, the biochemical mechanisms responsible for appropriate activation of these physiological events and which pathway is more crucial for plasma-mediated cytotoxicity have not been clarified. Understanding the molecular link between ROS/RNS-mediated apoptosis and DNA damage-involved chromosome instability is critical for the development of more efficacious therapeutic strategies for selective killing of diverse cancer cells.

  3. Metal and metalloid foliar uptake by various plant species exposed to atmospheric industrial fallout: mechanisms involved for lead.

    Science.gov (United States)

    Schreck, E; Foucault, Y; Sarret, G; Sobanska, S; Cécillon, L; Castrec-Rouelle, M; Uzu, G; Dumat, C

    2012-06-15

    Fine and ultrafine metallic particulate matters (PMs) are emitted from metallurgic activities in peri-urban zones into the atmosphere and can be deposited in terrestrial ecosystems. The foliar transfer of metals and metalloids and their fate in plant leaves remain unclear, although this way of penetration may be a major contributor to the transfer of metals into plants. This study focused on the foliar uptake of various metals and metalloids from enriched PM (Cu, Zn, Cd, Sn, Sb, As, and especially lead (Pb)) resulting from the emissions of a battery-recycling factory. Metal and metalloid foliar uptake by various vegetable species, exhibiting different morphologies, use (food or fodder) and life-cycle (lettuce, parsley and rye-grass) were studied. The mechanisms involved in foliar metal transfer from atmospheric particulate matter fallout, using lead (Pb) as a model element was also investigated. Several complementary techniques (micro-X-ray fluorescence, scanning electron microscopy coupled with energy dispersive X-ray microanalysis and time-of-flight secondary ion mass spectrometry) were used to investigate the localization and the speciation of lead in their edible parts, i.e. leaves. The results showed lead-enriched PM on the surface of plant leaves. Biogeochemical transformations occurred on the leaf surfaces with the formation of lead secondary species (PbCO(3) and organic Pb). Some compounds were internalized in their primary form (PbSO(4)) underneath an organic layer. Internalization through the cuticle or penetration through stomata openings are proposed as two major mechanisms involved in foliar uptake of particulate matter.

  4. Mechanisms of formation and function of eosinophil lipid bodies: inducible intracellular sites involved in arachidonic acid metabolism

    Directory of Open Access Journals (Sweden)

    Bozza Patricia T

    1997-01-01

    Full Text Available Lipid bodies, inducible lipid-rich cytoplasmic inclusions, are characteristically abundant in cells associated with inflammation, including eosinophils. Here we reviewed the formation and function of lipid bodies in human eosinophils. We now have evidence that the formation of lipid bodies is not attributable to adverse mechanisms, but is centrally mediated by specific signal transduction pathways. Arachidonic acid and other cis fatty acids by an NSAID-inhibitable process, diglycerides, and PAF by a 5-lipoxygenase dependent pathway are potent stimulators of lipid body induction. Lipid body formation develops rapidly by processes that involve PKC, PLC, and de novo mRNA and protein synthesis. These structures clearly serve as repositoires of arachidonyl-phospholipids and are more than inert depots. Specific enzymes, including cytosolic phospholipase A2, MAP kinases, lipoxygenases and cyclooxygenases, associate with lipid bodies. Lipid bodies appear to be dynamic, organelle-like structures involved in intracellular pathways of lipid mobilization and metabolism. Indeed, increases in lipid body numbers correlated with enhanced production of both lipoxygenase- and cyclooxygenase-derived eicosanoids. We hypothesize that lipid bodies are distinct inducible sites for generating eicosanoids as paracrine mediators with varied activities in inflammation. The capacity of lipid body formation to be specifically and rapidly induced in leukocytes enhances eicosanoid mediator formation, and conversely pharmacologic inhibition of lipid body induction represents a potential novel and specific target for anti-inflammatory therapy.

  5. Involvement of β-defensin 130 (DEFB130) in the macrophage microbicidal mechanisms for killing Plasmodium falciparum

    Science.gov (United States)

    Terkawi, Mohamad Alaa; Takano, Ryo; Furukawa, Atsushi; Murakoshi, Fumi; Kato, Kentaro

    2017-01-01

    Understanding the molecular defense mechanism of macrophages and identifying their effector molecules against malarial parasites may provide important clues for the discovery of new therapies. To analyze the immunological responses of malarial parasite-induced macrophages, we used DNA microarray technology to examine the gene profile of differentiated macrophages phagocytizing Plasmodium falciparum-parasitized erythrocytes (iRBC). The transcriptional gene profile of macrophages in response to iRBCs represented 168 down-regulated genes, which were mainly involved in the cellular immune response, and 216 upregulated genes, which were involved in cellular proteolysis, growth, and adhesion. Importantly, the specific upregulation of β-defensin 130 (DEFB130) in these macrophages suggested a possible role for DEFB130 in malarial parasite elimination. Differentiated macrophages phagocytizing iRBCs exhibited an increase in intracellular DEFB130 levels and DEFB130 appeared to accumulate at the site of iRBC engulfment. Transfection of esiRNA-mediated knockdown of DEFB130 into macrophages resulted in a remarkable reduction in their antiplasmodial activity in vitro. Furthermore, DEFB130 synthetic peptide exhibited a modest toxic effect on P. falciparum in vitro and P. yoelii in vivo, unlike scrambled DEFB130 peptide, which showed no antiplasmodial activity. Together, these results suggest that DEFB130 might be one of the macrophage effector molecules for eliminating malarial parasites. Our data broaden our knowledge of the immunological response of macrophages to iRBCs and shed light on a new target for therapeutic intervention. PMID:28181499

  6. Tetrahydrocannabinol Induces Brain Mitochondrial Respiratory Chain Dysfunction and Increases Oxidative Stress: A Potential Mechanism Involved in Cannabis-Related Stroke

    Directory of Open Access Journals (Sweden)

    Valérie Wolff

    2015-01-01

    Full Text Available Cannabis has potential therapeutic use but tetrahydrocannabinol (THC, its main psychoactive component, appears as a risk factor for ischemic stroke in young adults. We therefore evaluate the effects of THC on brain mitochondrial function and oxidative stress, key factors involved in stroke. Maximal oxidative capacities Vmax (complexes I, III, and IV activities, Vsucc (complexes II, III, and IV activities, Vtmpd (complex IV activity, together with mitochondrial coupling (Vmax/V0, were determined in control conditions and after exposure to THC in isolated mitochondria extracted from rat brain, using differential centrifugations. Oxidative stress was also assessed through hydrogen peroxide (H2O2 production, measured with Amplex Red. THC significantly decreased Vmax (−71%; P<0.0001, Vsucc (−65%; P<0.0001, and Vtmpd (−3.5%; P<0.001. Mitochondrial coupling (Vmax/V0 was also significantly decreased after THC exposure (1.8±0.2 versus 6.3±0.7; P<0.001. Furthermore, THC significantly enhanced H2O2 production by cerebral mitochondria (+171%; P<0.05 and mitochondrial free radical leak was increased from 0.01±0.01 to 0.10±0.01% (P<0.001. Thus, THC increases oxidative stress and induces cerebral mitochondrial dysfunction. This mechanism may be involved in young cannabis users who develop ischemic stroke since THC might increase patient’s vulnerability to stroke.

  7. Initial study on the possible mechanisms involved in the effects of high doses of perfluorooctane sulfonate (PFOS) on prolactin secretion.

    Science.gov (United States)

    Salgado, R; Pereiro, N; López-Doval, S; Lafuente, A

    2015-09-01

    Perfluorooctane sulfonate (PFOS) is a fluorinated organic compound. This chemical is neurotoxic and can alter the pituitary secretion. This is an initial study aimed at knowing the toxic effects of high doses of PFOS on prolactin secretion and the possible mechanisms involved in these alterations. For that, adult male rats were orally treated with 3.0 and 6.0 mg of PFOS/kg body weight (b.w.)/day for 28 days. At the end of the treatment, the serum levels of prolactin and estradiol as well as the concentration of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and gamma-aminobutyric acid (GABA) were quantified in the anterior and in the mediobasal hypothalamus. PFOS, at the administered doses, reduced prolactin and estradiol secretion, increased the concentration of dopamine and GABA in the anterior hypothalamus, and decreased the ratios DOPAC/dopamine and HVA/dopamine in this same hypothalamic area. The outcomes reported in this study suggest that (1) high doses of PFOS inhibit prolactin secretion in adult male rats; (2) only the periventricular-hypophysial dopaminergic (PHDA) neurons seem to be involved in this inhibitory effect but not the tuberoinfundibular dopaminergic (TIDA) and the tuberohypophysial dopaminergic (THDA) systems; (3) GABAergic cells from the paraventricular and supraoptic nuclei could be partially responsible for the PFOS action on prolactin secretion; and finally (4) estradiol might take part in the inhibition exerted by elevated concentration of PFOS on prolactin release.

  8. Mecanismos envolvidos na cicatrização: uma revisão Mechanisms involved in wound healing: a revision

    Directory of Open Access Journals (Sweden)

    Carlos Aberto Balbino

    2005-03-01

    Full Text Available Os mecanismos envolvidos no processo de reparo de tecidos estão revisados nesse trabalho. O processo de cicatrização ocorre fundamentalmente em três fases: inflamação, formação de tecido de granulação e deposição de matriz extracelular e remodelação. Os eventos celulares e tissulares de cada uma dessas fases estão descritos e discutidos. Os mediadores químicos estão correlacionados com os eventos do processo de cicatrização e as células envolvidas. Especial ênfase é dada à participação dos fatores de crescimento.The mechanisms involved in tissue repair are revised. The wound healing process occurs basically in three phases: inflammation, formation of granulating tissue and extracellular tissue deposition, and tissue remodeling. The cellular and tissue events of each phase are described and discussed. The chemical mediators and their interplay with the wound healing events and cells involved are also discussed. However, especial attention was given to the role played by the growth factors in the tissue repair process.

  9. Mechanisms involved in the vasorelaxant effects produced by the acute application of amfepramone in vitro to rat aortic rings

    Energy Technology Data Exchange (ETDEWEB)

    López-Canales, J.S. [Section of Postgraduate Studies and Investigation, Higher School of Medicine from the National Polytechnic Institute, Mexico City (Mexico); Department of Cellular Biology, National Institute of Perinatology, Mexico City (Mexico); Lozano-Cuenca, J.; Muãoz-Islas, E.; Aguilar-Carrasco, J.C. [Department of Cellular Biology, National Institute of Perinatology, Mexico City (Mexico); López-Canales, O.A.; López-Mayorga, R.M.; Castillo-Henkel, E.F.; Valencia-Hernández, I.; Castillo-Henkel, C. [Section of Postgraduate Studies and Investigation, Higher School of Medicine from the National Polytechnic Institute, Mexico City (Mexico)

    2015-03-27

    Amfepramone (diethylpropion) is an appetite-suppressant drug used for the treatment of overweight and obesity. It has been suggested that the systemic and central activity of amfepramone produces cardiovascular effects such as transient ischemic attacks and primary pulmonary hypertension. However, it is not known whether amfepramone produces immediate vascular effects when applied in vitro to rat aortic rings and, if so, what mechanisms may be involved. We analyzed the effect of amfepramone on phenylephrine-precontracted rat aortic rings with or without endothelium and the influence of inhibitors or blockers on this effect. Amfepramone produced a concentration-dependent vasorelaxation in phenylephrine-precontracted rat aortic rings that was not affected by the vehicle, atropine, 4-AP, glibenclamide, indomethacin, clotrimazole, or cycloheximide. The vasorelaxant effect of amfepramone was significantly attenuated by NG-nitro-L-arginine methyl ester (L-NAME) and tetraethylammonium (TEA), and was blocked by removal of the vascular endothelium. These results suggest that amfepramone had a direct vasorelaxant effect on phenylephrine-precontracted rat aortic rings, and that inhibition of endothelial nitric oxide synthase and the opening of Ca{sup 2+}-activated K{sup +} channels were involved in this effect.

  10. Decreased autocrine EGFR signaling in metastatic breast cancer cells inhibits tumor growth in bone and mammary fat pad.

    Science.gov (United States)

    Nickerson, Nicole K; Mohammad, Khalid S; Gilmore, Jennifer L; Crismore, Erin; Bruzzaniti, Angela; Guise, Theresa A; Foley, John

    2012-01-01

    Breast cancer metastasis to bone triggers a vicious cycle of tumor growth linked to osteolysis. Breast cancer cells and osteoblasts express the epidermal growth factor receptor (EGFR) and produce ErbB family ligands, suggesting participation of these growth factors in autocrine and paracrine signaling within the bone microenvironment. EGFR ligand expression was profiled in the bone metastatic MDA-MB-231 cells (MDA-231), and agonist-induced signaling was examined in both breast cancer and osteoblast-like cells. Both paracrine and autocrine EGFR signaling were inhibited with a neutralizing amphiregulin antibody, PAR34, whereas shRNA to the EGFR was used to specifically block autocrine signaling in MDA-231 cells. The impact of these was evaluated with proliferation, migration and gene expression assays. Breast cancer metastasis to bone was modeled in female athymic nude mice with intratibial inoculation of MDA-231 cells, and cancer cell-bone marrow co-cultures. EGFR knockdown, but not PAR34 treatment, decreased osteoclasts formed in vitro (p<0.01), reduced osteolytic lesion tumor volume (p<0.01), increased survivorship in vivo (p<0.001), and resulted in decreased MDA-231 growth in the fat pad (p<0.01). Fat pad shEGFR-MDA-231 tumors produced in nude mice had increased necrotic areas and decreased CD31-positive vasculature. shEGFR-MDA-231 cells also produced decreased levels of the proangiogenic molecules macrophage colony stimulating factor-1 (MCSF-1) and matrix metalloproteinase 9 (MMP9), both of which were decreased by EGFR inhibitors in a panel of EGFR-positive breast cancer cells. Thus, inhibiting autocrine EGFR signaling in breast cancer cells may provide a means for reducing paracrine factor production that facilitates microenvironment support in the bone and mammary gland.

  11. Decreased autocrine EGFR signaling in metastatic breast cancer cells inhibits tumor growth in bone and mammary fat pad.

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    Nicole K Nickerson

    Full Text Available Breast cancer metastasis to bone triggers a vicious cycle of tumor growth linked to osteolysis. Breast cancer cells and osteoblasts express the epidermal growth factor receptor (EGFR and produce ErbB family ligands, suggesting participation of these growth factors in autocrine and paracrine signaling within the bone microenvironment. EGFR ligand expression was profiled in the bone metastatic MDA-MB-231 cells (MDA-231, and agonist-induced signaling was examined in both breast cancer and osteoblast-like cells. Both paracrine and autocrine EGFR signaling were inhibited with a neutralizing amphiregulin antibody, PAR34, whereas shRNA to the EGFR was used to specifically block autocrine signaling in MDA-231 cells. The impact of these was evaluated with proliferation, migration and gene expression assays. Breast cancer metastasis to bone was modeled in female athymic nude mice with intratibial inoculation of MDA-231 cells, and cancer cell-bone marrow co-cultures. EGFR knockdown, but not PAR34 treatment, decreased osteoclasts formed in vitro (p<0.01, reduced osteolytic lesion tumor volume (p<0.01, increased survivorship in vivo (p<0.001, and resulted in decreased MDA-231 growth in the fat pad (p<0.01. Fat pad shEGFR-MDA-231 tumors produced in nude mice had increased necrotic areas and decreased CD31-positive vasculature. shEGFR-MDA-231 cells also produced decreased levels of the proangiogenic molecules macrophage colony stimulating factor-1 (MCSF-1 and matrix metalloproteinase 9 (MMP9, both of which were decreased by EGFR inhibitors in a panel of EGFR-positive breast cancer cells. Thus, inhibiting autocrine EGFR signaling in breast cancer cells may provide a means for reducing paracrine factor production that facilitates microenvironment support in the bone and mammary gland.

  12. Huang Qi Jian Zhong Pellet Attenuates TNBS-Induced Colitis in Rats via Mechanisms Involving Improvement of Energy Metabolism.

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    Liu, Duan-Yong; Pan, Chun-Shui; Liu, Yu-Ying; Wei, Xiao-Hong; Zhou, Chang-Man; Sun, Kai; He, Ke; Li, Chong; Yan, Li; Fan, Jing-Yu; Wang, Chuan-She; Hibi, Toshifumi; Liu, Hong-Ning; Han, Jing-Yan

    2013-01-01

    Huang Qi Jian Zhong Pellet (HQJZ) is a famous Chinese medicine formula for treatment of various gastrointestinal tract diseases. This study investigated the role of HQJZ in 2,4,6-trinitrobenzene sulfonic acid- (TNBS-) induced colitis and its underlying mechanism. Colonic mucosal injury was induced by TNBS in the Sprague-Dawley rats. In the HQJZ treatment group, HQJZ was administered (2 g/kg) for 14 days starting from day 1 after TNBS infusion. Colonic mucosal injury occurred obviously 1 day after TNBS challenge and did not recover distinctively until day 15, including an increase in macro- and microscopic scores, a colonic weight index, a decrease in colonic length, a number of functional capillaries, and blood flow. Inverted intravital microscopy and ELISA showed colonic microcirculatory disturbances and inflammatory responses after TNBS stimulation, respectively. TNBS decreased occludin, RhoA, and ROCK-I, while increasing Rac-1, PAK-1, and phosphorylated myosin light chain. In addition, ATP content and ATP5D expression in colonic mucosa decreased after TNBS challenge. Impressively, treatment with HQJZ significantly attenuated all of the alterations evoked by TNBS, promoting the recovery of colonic injury. The present study demonstrated HQJZ as a multitargeting management for colonic mucosal injury, which set in motion mechanisms involving improvement of energy metabolism.

  13. Huang Qi Jian Zhong Pellet Attenuates TNBS-Induced Colitis in Rats via Mechanisms Involving Improvement of Energy Metabolism

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    Duan-Yong Liu

    2013-01-01

    Full Text Available Huang Qi Jian Zhong Pellet (HQJZ is a famous Chinese medicine formula for treatment of various gastrointestinal tract diseases. This study investigated the role of HQJZ in 2,4,6-trinitrobenzene sulfonic acid- (TNBS- induced colitis and its underlying mechanism. Colonic mucosal injury was induced by TNBS in the Sprague-Dawley rats. In the HQJZ treatment group, HQJZ was administered (2 g/kg for 14 days starting from day 1 after TNBS infusion. Colonic mucosal injury occurred obviously 1 day after TNBS challenge and did not recover distinctively until day 15, including an increase in macro- and microscopic scores, a colonic weight index, a decrease in colonic length, a number of functional capillaries, and blood flow. Inverted intravital microscopy and ELISA showed colonic microcirculatory disturbances and inflammatory responses after TNBS stimulation, respectively. TNBS decreased occludin, RhoA, and ROCK-I, while increasing Rac-1, PAK-1, and phosphorylated myosin light chain. In addition, ATP content and ATP5D expression in colonic mucosa decreased after TNBS challenge. Impressively, treatment with HQJZ significantly attenuated all of the alterations evoked by TNBS, promoting the recovery of colonic injury. The present study demonstrated HQJZ as a multitargeting management for colonic mucosal injury, which set in motion mechanisms involving improvement of energy metabolism.

  14. Effects and mechanisms of 3α,5α,-THP on emotion, motivation, and reward functions involving pregnane xenobiotic receptor

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    Cheryl A Frye

    2012-01-01

    Full Text Available Progestogens [progesterone (P4 and its products] play fundamental roles in the development and/or function of the central nervous system during pregnancy. We, and others, have investigated the role of pregnane neurosteroids for a plethora of functional effects beyond their pro-gestational processes. Emerging findings regarding the effects, mechanisms, and sources of neurosteroids have challenged traditional dogma about steroid action. How the P4 metabolite and neurosteroid, 3α-hydroxy-5α-pregnan-20-one (3α,5α-THP, influences cellular functions and behavioral processes involved in emotion/affect, motivation, and reward, is the focus of the present review. To further understand these processes, we have utilized an animal model assessing the effects, mechanisms, and sources of 3α,5α-THP. In the ventral tegmental area (VTA, 3α,5α-THP has actions to facilitate affective, and motivated, social behaviors through non-traditional targets, such as GABA, glutamate, and dopamine receptors. 3α,5α-THP levels in the midbrain VTA both facilitate, and/or are enhanced by, affective and social behavior. The pregnane xenobiotic receptor (PXR mediates the production of, and/or metabolism to, various neurobiological factors. PXR is localized to the midbrain VTA of rats. The role of PXR to influence 3α,5α-THP production from central biosynthesis, and/or metabolism of peripheral P4, in the VTA, as well as its role to facilitate, or be increased by, affective/social behaviors is under investigation. Investigating novel behavioral functions of 3α,5α-THP extends our knowledge of the neurobiology of progestogens, relevant for affective/social behaviors, and their connections to systems that regulate affect and motivated processes, such as those important for stress regulation and neuropsychiatric disorders (anxiety, depression, schizophrenia, drug dependence. Thus, further understanding of 3α,5α-THP’s role and mechanisms to enhance affective and motivated

  15. Effects and Mechanisms of 3α,5α,-THP on Emotion, Motivation, and Reward Functions Involving Pregnane Xenobiotic Receptor.

    Science.gov (United States)

    Frye, Cheryl A; Paris, J J; Walf, A A; Rusconi, J C

    2011-01-01

    Progestogens [progesterone (P(4)) and its products] play fundamental roles in the development and/or function of the central nervous system during pregnancy. We, and others, have investigated the role of pregnane neurosteroids for a plethora of functional effects beyond their pro-gestational processes. Emerging findings regarding the effects, mechanisms, and sources of neurosteroids have challenged traditional dogma about steroid action. How the P(4) metabolite and neurosteroid, 3α-hydroxy-5α-pregnan-20-one (3α,5α-THP), influences cellular functions and behavioral processes involved in emotion/affect, motivation, and reward, is the focus of the present review. To further understand these processes, we have utilized an animal model assessing the effects, mechanisms, and sources of 3α,5α-THP. In the ventral tegmental area (VTA), 3α,5α-THP has actions to facilitate affective, and motivated, social behaviors through non-traditional targets, such as GABA, glutamate, and dopamine receptors. 3α,5α-THP levels in the midbrain VTA both facilitate, and/or are enhanced by, affective and social behavior. The pregnane xenobiotic receptor (PXR) mediates the production of, and/or metabolism to, various neurobiological factors. PXR is localized to the midbrain VTA of rats. The role of PXR to influence 3α,5α-THP production from central biosynthesis, and/or metabolism of peripheral P(4), in the VTA, as well as its role to facilitate, or be increased by, affective/social behaviors is under investigation. Investigating novel behavioral functions of 3α,5α-THP extends our knowledge of the neurobiology of progestogens, relevant for affective/social behaviors, and their connections to systems that regulate affect and motivated processes, such as those important for stress regulation and neuropsychiatric disorders (anxiety, depression, schizophrenia, drug dependence). Thus, further understanding of 3α,5α-THP's role and mechanisms to enhance affective and motivated processes

  16. Structure reveals regulatory mechanisms of a MaoC-like hydratase from Phytophthora capsici involved in biosynthesis of polyhydroxyalkanoates (PHAs.

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    Huizheng Wang

    Full Text Available BACKGROUND: Polyhydroxyalkanoates (PHAs have attracted increasing attention as "green plastic" due to their biodegradable, biocompatible, thermoplastic, and mechanical properties, and considerable research has been undertaken to develop low cost/high efficiency processes for the production of PHAs. MaoC-like hydratase (MaoC, which belongs to (R-hydratase involved in linking the β-oxidation and the PHA biosynthetic pathways, has been identified recently. Understanding the regulatory mechanisms of (R-hydratase catalysis is critical for efficient production of PHAs that promise synthesis an environment-friendly plastic. METHODOLOGY/PRINCIPAL FINDINGS: We have determined the crystal structure of a new MaoC recognized from Phytophthora capsici. The crystal structure of the enzyme was solved at 2.00 Å resolution. The structure shows that MaoC has a canonical (R-hydratase fold with an N-domain and a C-domain. Supporting its dimerization observed in structure, MaoC forms a stable homodimer in solution. Mutations that disrupt the dimeric MaoC result in a complete loss of activity toward crotonyl-CoA, indicating that dimerization is required for the enzymatic activity of MaoC. Importantly, structure comparison reveals that a loop unique to MaoC interacts with an α-helix that harbors the catalytic residues of MaoC. Deletion of the loop enhances the enzymatic activity of MaoC, suggesting its inhibitory role in regulating the activity of MaoC. CONCLUSIONS/SIGNIFICANCE: The data in our study reveal the regulatory mechanism of an (R-hydratase, providing information on enzyme engineering to produce low cost PHAs.

  17. Autocrine abscisic acid plays a key role in quartz-induced macrophage activation.

    Science.gov (United States)

    Magnone, Mirko; Sturla, Laura; Jacchetti, Emanuela; Scarfì, Sonia; Bruzzone, Santina; Usai, Cesare; Guida, Lucrezia; Salis, Annalisa; Damonte, Gianluca; De Flora, Antonio; Zocchi, Elena

    2012-03-01

    Inhalation of quartz induces silicosis, a lung disease where alveolar macrophages release inflammatory mediators, including prostaglandin-E(2) (PGE(2)) and tumor necrosis factor α (TNF-α). Here we report the pivotal role of abscisic acid (ABA), a recently discovered human inflammatory hormone, in silica-induced activation of murine RAW264.7 macrophages and of rat alveolar macrophages (AMs). Stimulation of both RAW264.7 cells and AMs with quartz induced a significant increase of ABA release (5- and 10-fold, respectively), compared to untreated cells. In RAW264.7 cells, autocrine ABA released after quartz stimulation sequentially activates the plasma membrane receptor LANCL2 and NADPH oxidase, generating a Ca(2+) influx resulting in NFκ B nuclear translocation and PGE(2) and TNF-α release (3-, 2-, and 3.5-fold increase, respectively, compared to control, unstimulated cells). Quartz-stimulated RAW264.7 cells silenced for LANCL2 or preincubated with a monoclonal antibody against ABA show an almost complete inhibition of NFκ B nuclear translocation and PGE(2) and TNF-α release compared to controls electroporated with a scramble oligonucleotide or preincubated with an unrelated antibody. AMs showed similar early and late ABA-induced responses as RAW264.7 cells. These findings identify ABA and LANCL2 as key mediators in quartz-induced inflammation, providing possible new targets for antisilicotic therapy.

  18. Autocrine and paracrine roles for ATP and serotonin in mouse taste buds.

    Science.gov (United States)

    Huang, Yijen A; Dando, Robin; Roper, Stephen D

    2009-11-01

    Receptor (type II) taste bud cells secrete ATP during taste stimulation. In turn, ATP activates adjacent presynaptic (type III) cells to release serotonin (5-hydroxytryptamine, or 5-HT) and norepinephrine (NE). The roles of these neurotransmitters in taste buds have not been fully elucidated. Here we tested whether ATP or 5-HT exert feedback onto receptor (type II) cells during taste stimulation. Our previous studies showed NE does not appear to act on adjacent taste bud cells, or at least on receptor cells. Our data show that 5-HT released from presynaptic (type III) cells provides negative paracrine feedback onto receptor cells by activating 5-HT(1A) receptors, inhibiting taste-evoked Ca(2+) mobilization in receptor cells, and reducing ATP secretion. The findings also demonstrate that ATP exerts positive autocrine feedback onto receptor (type II) cells by activating P2Y1 receptors and enhancing ATP secretion. These results begin to sort out how purinergic and aminergic transmitters function within the taste bud to modulate gustatory signaling in these peripheral sensory organs.

  19. Interleukin-19 acts as a negative autocrine regulator of activated microglia.

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    Hiroshi Horiuchi

    Full Text Available Activated microglia can exert either neurotoxic or neuroprotective effects, and they play pivotal roles in the pathogenesis and progression of various neurological diseases. In this study, we used cDNA microarrays to show that interleukin-19 (IL-19, an IL-10 family cytokine, is markedly upregulated in activated microglia. Furthermore, we found that microglia are the only cells in the nervous system that express the IL-19 receptor, a heterodimer of the IL-20Rα and IL-20Rβ subunits. IL-19 deficiency increased the production of such pro-inflammatory cytokines as IL-6 and tumor necrosis factor-α in activated microglia, and IL-19 treatment suppressed this effect. Moreover, in a mouse model of Alzheimer's disease, we observed upregulation of IL-19 in affected areas in association with disease progression. Our findings demonstrate that IL-19 is an anti-inflammatory cytokine, produced by activated microglia, that acts negatively on microglia in an autocrine manner. Thus, microglia may self-limit their inflammatory response by producing the negative regulator IL-19.

  20. MCP-1 expressed by osteoclasts stimulates osteoclastogenesis in an autocrine/paracrine manner

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, Kana [Department of Orthopedic Surgery, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan); Division of Orthopedic Research, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan); Department of Cell Differentiation, The Sakaguchi Laboratory of Developmental Biology, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan); Ninomiya, Ken [Department of Orthopedic Surgery, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan); Department of Cell Differentiation, The Sakaguchi Laboratory of Developmental Biology, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan); Sonoda, Koh-Hei [Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582 (Japan); Miyauchi, Yoshiteru; Hoshi, Hiroko [Department of Orthopedic Surgery, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan); Division of Orthopedic Research, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan); Iwasaki, Ryotaro [Division of Orthopedic Research, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan); Department of Cell Differentiation, The Sakaguchi Laboratory of Developmental Biology, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan); Department of Dentistry and Oral Surgery, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan); Miyamoto, Hiroya [Department of Orthopedic Surgery, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan); Division of Orthopedic Research, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan); and others

    2009-06-05

    Monocyte chemoattractant protein-1 (MCP-1) is a chemokine that plays a critical role in the recruitment and activation of leukocytes. Here, we describe that multinuclear osteoclast formation was significantly inhibited in cells derived from MCP-1-deficient mice. MCP-1 has been implicated in the regulation of osteoclast cell-cell fusion; however defects of multinuclear osteoclast formation in the cells from mice deficient in DC-STAMP, a seven transmembrane receptor essential for osteoclast cell-cell fusion, was not rescued by recombinant MCP-1. The lack of MCP-1 in osteoclasts resulted in a down-regulation of DC-STAMP, NFATc1, and cathepsin K, all of which were highly expressed in normal osteoclasts, suggesting that osteoclast differentiation was inhibited in MCP-1-deficient cells. MCP-1 alone did not induce osteoclastogenesis, however, the inhibition of osteoclastogenesis in MCP-1-deficient cells was restored by addition of recombinant MCP-1, indicating that osteoclastogenesis was regulated in an autocrine/paracrine manner by MCP-1 under the stimulation of RANKL in osteoclasts.

  1. Autocrine/paracrine dopamine in the salivary glands of the blacklegged tick Ixodes scapularis.

    Science.gov (United States)

    Koči, Juraj; Simo, Ladislav; Park, Yoonseong

    2014-03-01

    Dopamine (DA) is known to be the most potent activator of tick salivary secretion, which is an essential component of successful tick feeding. We examined the quantitative changes of catecholamines using a method coupling high-pressure liquid chromatography with electrochemical detection (HPLC-ECD). We also investigated the levels of catecholamines conjugated to other molecules utilising appropriate methods to hydrolyse the conjugates. Three different biological samples, salivary glands, synganglia, ovaries and haemolymph were compared, and the largest quantity of DA was detected in salivary gland extracts (up to ∼100pg/tick), supporting the hypothesis that autocrine/paracrine dopamine activates salivary secretion. Quantitative changes of catecholamines in the salivary glands over the entire blood feeding duration were examined. The amount of dopamine in the salivary glands increased until the day 5 of feeding, at which the rapid engorgement phase began. We also detected a small but significant amount of norepinephrine in the salivary glands. Interestingly, saliva collected after induction of salivary secretion by the cholinergic agonist pilocarpine contained a large amount of DA sulphate with a trace amount of DA, suggesting a potential biological role of DA sulphate in tick saliva.

  2. Autocrine and Paracrine Actions of IGF-I Signaling in Skeletal Development

    Institute of Scientific and Technical Information of China (English)

    Yongmei Wang; Daniel D. Bikle; Wenhan Chang

    2013-01-01

    Insulin-like growth factor-I (IGF-I) regulates cell growth, survival, and differentiation by acting on the IGF-I receptor, (IGF-IR)-a tyrosine kinase receptor, which elicits diverse intracellular signaling responses. All skeletal cells express IGF-I and IGF-IR. Recent studies using tissue/cell-specific gene knockout mouse models and cell culture techniques have clearly demonstrated that locally produced IGF-I is more critical than the systemic IGF-I in supporting embryonic and postnatal skeletal development and bone remodeling. Local IGF-I/IGF-IR signaling promotes the growth, survival and differentiation of chondrocytes and osteo-blasts, directly and indirectly, by altering other autocrine/paracrine signaling pathways in cartilage and bone, and by enhancing interactions among these skeletal cells through hormonal and physical means. Moreover, local IGF-I/IGF-IR signaling is critical for the anabolic bone actions of growth hormone and parathyroid hormone. Herein, we review evidence supporting the actions of local IGF-I/IGF-IR in the above aspects of skeletal development and remodeling.

  3. Raft-dependent endocytosis of autocrine motility factor/phosphoglucose isomerase: a potential drug delivery route for tumor cells.

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    Liliana D Kojic

    Full Text Available BACKGROUND: Autocrine motility factor/phosphoglucose isomerase (AMF/PGI is the extracellular ligand for the gp78/AMFR receptor overexpressed in a variety of human cancers. We showed previously that raft-dependent internalization of AMF/PGI is elevated in metastatic MDA-435 cells, but not metastatic, caveolin-1-expressing MDA-231 cells, relative to non-metastatic MCF7 and dysplastic MCF10A cells suggesting that it might represent a tumor cell-specific endocytic pathway. METHODOLOGY/PRINCIPAL FINDINGS: Similarly, using flow cytometry, we demonstrate that raft-dependent endocytosis of AMF/PGI is increased in metastatic HT29 cancer cells expressing low levels of caveolin-1 relative to metastatic, caveolin-1-expressing, HCT116 colon cells and non-metastatic Caco-2 cells. Therefore, we exploited the raft-dependent internalization of AMF/PGI as a potential tumor-cell specific targeting mechanism. We synthesized an AMF/PGI-paclitaxel conjugate and found it to be as efficient as free paclitaxel in inducing cytotoxicity and apoptosis in tumor cells that readily internalize AMF/PGI compared to tumor cells that poorly internalize AMF/PGI. Murine K1735-M1 and B16-F1 melanoma cells internalize FITC-conjugated AMF/PGI and are acutely sensitive to AMF/PGI-paclitaxel mediated cytotoxicity in vitro. Moreover, following in vivo intratumoral injection, FITC-conjugated AMF/PGI is internalized in K1735-M1 tumors. Intratumoral injection of AMF/PGI-paclitaxel induced significantly higher tumor regression compared to free paclitaxel, even in B16-F1 cells, known to be resistant to taxol treatment. Treatment with AMF/PGI-paclitaxel significantly prolonged the median survival time of tumor bearing mice. Free AMF/PGI exhibited a pro-survival role, reducing the cytotoxic effect of both AMF/PGI-paclitaxel and free paclitaxel suggesting that AMF/PGI-paclitaxel targets a pathway associated with resistance to chemotherapeutic agents. AMF/PGI-FITC uptake by normal murine spleen

  4. Insights into the Mechanisms Involved in the Expression and Regulation of Extracellular Matrix Proteins in Diabetic Nephropathy.

    Science.gov (United States)

    Hu, C; Sun, L; Xiao, L; Han, Y; Fu, X; Xiong, X; Xu, X; Liu, Y; Yang, S; Liu, F; Kanwar, Y S

    2015-01-01

    Diabetic Nephropathy (DN) is believed to be a major microvascular complication of diabetes. The hallmark of DN includes deposition of Extracellular Matrix (ECM) proteins, such as, collagen, laminin and fibronectin in the mesangium and renal tubulo-interstitium of the glomerulus and basement membranes. Such an increased expression of ECM leads to glomerular and tubular basement membranes thickening and increase of mesangial matrix, ultimately resulting in glomerulosclerosis and tubulointerstitial fibrosis. The characteristic morphologic glomerular mesangial lesion has been described as Kimmelstiel-Wilson nodule, and the process at times is referred to as diabetic nodular glomerulosclerosis. Thus, the accumulation of ECM proteins plays a critical role in the development of DN. The relevant mechanism(s) involved in the increased ECM expression and their regulation in the kidney in diabetic state has been extensively investigated and documented in the literature. Nevertheless, there are certain other mechanisms that may yet be conclusively defined. Recent studies demonstrated that some of the new signaling pathways or molecules including, Notch, Wnt, mTOR, TLRs and small GTPase may play a pivotal role in the modulation of ECM regulation and expression in DN. Such modulation could be operational for instance Notch through Notch1/Jagged1 signaling, Wnt by Wnt/β- catenin pathway and mTOR via PI3-K/Akt/mTOR signaling pathways. All these pathways may be critical in the modulation of ECM expression and tubulo-interstitial fibrosis. In addition, TLRs, mainly the TLR2 and TLR4, by TLR2- dependent and TGF-β-dependent conduits, may modulate ECM expression and generate a fibrogenic response. Small GTPase like Rho, Ras and Rab family by targeting relevant genes may also influence the accumulation of ECM proteins and renal fibrosis in hyperglycemic states. This review summarizes the recent information about the role and mechanisms by which these molecules and signaling pathways

  5. Nodal promotes the self-renewal of human colon cancer stem cells via an autocrine manner through Smad2/3 signaling pathway.

    Science.gov (United States)

    Gong, Yuehua; Guo, Ying; Hai, Yanan; Yang, Hao; Liu, Yang; Yang, Shi; Zhang, Zhenzhen; Ma, Meng; Liu, Linhong; Li, Zheng; He, Zuping

    2014-01-01

    Colorectal cancer is one of the most common and fatal tumors. However, molecular mechanisms underlying carcinogenesis of colorectal cancer remain largely undefined. Here, we explored the expression and function of Nodal in colon cancer stem cells (CCSCs). Nodal and its receptors were present in numerous human colorectal cancer cell lines. NODAL and ALK-4 were coexpressed in human colon cancerous tissues, and NODAL, CD24, and CD44, markers for CCSCs, were expressed at higher levels in human colon cancerous tissues than adjacent noncancerous colon tissues. Human CCSCs were isolated by magnetic activated cell sorting using anti-CD24 and anti-CD44. Nodal transcript and protein were hardly detectable in CD44- or CD24-negative human colorectal cancer cell lines, whereas Nodal and its receptors were present in CCSCs. Notably, Nodal facilitated spheroid formation of human CCSCs, and phosphorylation of Smad2 and Smad3 was activated by Nodal in cells of spheres derived from human CCSCs. Collectively, these results suggest that Nodal promotes the self-renewal of human CCSCs and mediate carcinogenesis of human colorectal cancer via an autocrine manner through Smad2/3 pathway. This study provides a novel insight into molecular mechanisms controlling fate of human CCSCs and offers new targets for gene therapy of human colorectal cancer.

  6. Mechanisms Involved in Acquisition of blaNDM Genes by IncA/C2 and IncFIIY Plasmids.

    Science.gov (United States)

    Wailan, Alexander M; Sidjabat, Hanna E; Yam, Wan Keat; Alikhan, Nabil-Fareed; Petty, Nicola K; Sartor, Anna L; Williamson, Deborah A; Forde, Brian M; Schembri, Mark A; Beatson, Scott A; Paterson, David L; Walsh, Timothy R; Partridge, Sally R

    2016-07-01

    blaNDM genes confer carbapenem resistance and have been identified on transferable plasmids belonging to different incompatibility (Inc) groups. Here we present the complete sequences of four plasmids carrying a blaNDM gene, pKP1-NDM-1, pEC2-NDM-3, pECL3-NDM-1, and pEC4-NDM-6, from four clinical samples originating from four different patients. Different plasmids carry segments that align to different parts of the blaNDM region found on Acinetobacter plasmids. pKP1-NDM-1 and pEC2-NDM-3, from Klebsiella pneumoniae and Escherichia coli, respectively, were identified as type 1 IncA/C2 plasmids with almost identical backbones. Different regions carrying blaNDM are inserted in different locations in the antibiotic resistance island known as ARI-A, and ISCR1 may have been involved in the acquisition of blaNDM-3 by pEC2-NDM-3. pECL3-NDM-1 and pEC4-NDM-6, from Enterobacter cloacae and E. coli, respectively, have similar IncFIIY backbones, but different regions carrying blaNDM are found in different locations. Tn3-derived inverted-repeat transposable elements (TIME) appear to have been involved in the acquisition of blaNDM-6 by pEC4-NDM-6 and the rmtC 16S rRNA methylase gene by IncFIIY plasmids. Characterization of these plasmids further demonstrates that even very closely related plasmids may have acquired blaNDM genes by different mechanisms. These findings also illustrate the complex relationships between antimicrobial resistance genes, transposable elements, and plasmids and provide insights into the possible routes for transmission of blaNDM genes among species of the Enterobacteriaceae family.

  7. Amino acid residues involved in the catalytic mechanism of NAD-dependent glutamate dehydrogenase from Halobacterium salinarum.

    Science.gov (United States)

    Pérez-Pomares, F; Ferrer, J; Camacho, M; Pire, C; LLorca, F; Bonete, M J

    1999-02-01

    The pH dependence of kinetic parameters for a competitive inhibitor (glutarate) was determined in order to obtain information on the chemical mechanism for NAD-dependent glutamate dehydrogenase from Halobacterium salinarum. The maximum velocity is pH dependent, decreasing at low pHs giving a pK value of 7.19+/-0.13, while the V/K for l-glutamate at 30 degrees C decreases at low and high pHs, yielding pK values of 7.9+/-0.2 and 9.8+/-0.2, respectively. The glutarate pKis profile decreases at high pHs, yielding a pK of 9. 59+/-0.09 at 30 degrees C. The values of ionization heat calculated from the change in pK with temperature are: 1.19 x 10(4), 5.7 x 10(3), 7 x 10(3), 6.6 x 10(3) cal mol-1, for the residues involved. All these data suggest that the groups required for catalysis and/or binding are lysine, histidine and tyrosine. The enzyme shows a time-dependent loss in glutamate oxidation activity when incubated with diethyl pyrocarbonate (DEPC). Inactivation follows pseudo-first-order kinetics with a second-order rate constant of 53 M-1min-1. The pKa of the titratable group was pK1=6.6+/-0.6. Inactivation with ethyl acetimidate also shows pseudo-first-order kinetics as well as inactivation with TNM yielding second-order constants of 1.2 M-1min-1 and 2.8 M-1min-1, and pKas of 8.36 and 9.0, respectively. The proposed mechanism involves hydrogen binding of each of the two carboxylic groups to tyrosyl residues; histidine interacts with one of the N-hydrogens of the l-glutamate amino group. We also corroborate the presence of a conservative lysine that has a remarkable ability to coordinate a water molecule that would act as general base.

  8. Mechanism of ghrelin-induced gastric contractions in Suncus murinus (house musk shrew: involvement of intrinsic primary afferent neurons.

    Directory of Open Access Journals (Sweden)

    Anupom Mondal

    Full Text Available Here, we have reported that motilin can induce contractions in a dose-dependent manner in isolated Suncus murinus (house musk shrew stomach. We have also shown that after pretreatment with a low dose of motilin (10(-10 M, ghrelin also induces gastric contractions at levels of 10(-10 M to 10(-7 M. However, the neural mechanism of ghrelin action in the stomach has not been fully revealed. In the present study, we studied the mechanism of ghrelin-induced contraction in vitro using a pharmacological method. The responses to ghrelin in the stomach were almost completely abolished by hexamethonium and were significantly suppressed by the administration of phentolamine, prazosin, ondansetron, and naloxone. Additionally, N-nitro-l-arginine methylester significantly potentiated the contractions. Importantly, the mucosa is essential for ghrelin-induced, but not motilin-induced, gastric contractions. To evaluate the involvement of intrinsic primary afferent neurons (IPANs, which are multiaxonal neurons that pass signals from the mucosa to the myenteric plexus, we examined the effect of the IPAN-related pathway on ghrelin-induced contractions and found that pretreatment with adenosine and tachykinergic receptor 3 antagonists (SR142801 significantly eliminated the contractions and GR113808 (5-hydroxytryptamine receptor 4 antagonist almost completely eliminated it. The results indicate that ghrelin stimulates and modulates suncus gastric contractions through cholinergic, adrenergic, serotonergic, opioidergic neurons and nitric oxide synthases in the myenteric plexus. The mucosa is also important for ghrelin-induced gastric contractions, and IPANs may be the important interneurons that pass the signal from the mucosa to the myenteric plexus.

  9. Mechanism of ghrelin-induced gastric contractions in Suncus murinus (house musk shrew): involvement of intrinsic primary afferent neurons.

    Science.gov (United States)

    Mondal, Anupom; Aizawa, Sayaka; Sakata, Ichiro; Goswami, Chayon; Oda, Sen-ichi; Sakai, Takafumi

    2013-01-01

    Here, we have reported that motilin can induce contractions in a dose-dependent manner in isolated Suncus murinus (house musk shrew) stomach. We have also shown that after pretreatment with a low dose of motilin (10(-10) M), ghrelin also induces gastric contractions at levels of 10(-10) M to 10(-7) M. However, the neural mechanism of ghrelin action in the stomach has not been fully revealed. In the present study, we studied the mechanism of ghrelin-induced contraction in vitro using a pharmacological method. The responses to ghrelin in the stomach were almost completely abolished by hexamethonium and were significantly suppressed by the administration of phentolamine, prazosin, ondansetron, and naloxone. Additionally, N-nitro-l-arginine methylester significantly potentiated the contractions. Importantly, the mucosa is essential for ghrelin-induced, but not motilin-induced, gastric contractions. To evaluate the involvement of intrinsic primary afferent neurons (IPANs), which are multiaxonal neurons that pass signals from the mucosa to the myenteric plexus, we examined the effect of the IPAN-related pathway on ghrelin-induced contractions and found that pretreatment with adenosine and tachykinergic receptor 3 antagonists (SR142801) significantly eliminated the contractions and GR113808 (5-hydroxytryptamine receptor 4 antagonist) almost completely eliminated it. The results indicate that ghrelin stimulates and modulates suncus gastric contractions through cholinergic, adrenergic, serotonergic, opioidergic neurons and nitric oxide synthases in the myenteric plexus. The mucosa is also important for ghrelin-induced gastric contractions, and IPANs may be the important interneurons that pass the signal from the mucosa to the myenteric plexus.

  10. The pressor effect of angiotensin-(1-7 in the rat rostral ventrolateral medulla involves multiple peripheral mechanisms

    Directory of Open Access Journals (Sweden)

    Rita C. Oliveira

    2013-01-01

    Full Text Available OBJECTIVE: In the present study, the peripheral mechanism that mediates the pressor effect of angiotensin-(1-7 in the rostral ventrolateral medulla was investigated. METHOD: Angiotensin-(1-7 (25 pmol was bilaterally microinjected in the rostral ventrolateral medulla near the ventral surface in urethane-anesthetized male Wistar rats that were untreated or treated (intravenously with effective doses of selective autonomic receptor antagonists (atenolol, prazosin, methyl-atropine, and hexamethonium or a vasopressin V1 receptor antagonist [d(CH25 -Tyr(Me-AVP] given alone or in combination. RESULTS: Unexpectedly, the pressor response produced by angiotensin-(1-7 (16 ± 2 mmHg, n = 12, which was not associated with significant changes in heart rate, was not significantly altered by peripheral treatment with prazosin, the vasopressin V1 receptor antagonist, hexamethonium or methyl-atropine. Similar results were obtained in experiments that tested the association of prazosin and atenolol; methyl-atropine and the vasopressin V1 antagonist or methyl-atropine and prazosin. Peripheral treatment with the combination of prazosin, atenolol and the vasopressin V1 antagonist abolished the pressor effect of glutamate; however, this treatment produced only a small decrease in the pressor effect of angiotensin-(1-7 at the rostral ventrolateral medulla. The combination of hexamethonium with the vasopressin V1 receptor antagonist or the combination of prazosin, atenolol, the vasopressin V1 receptor antagonist and methyl-atropine was effective in blocking the effect of angiotensin-(1-7 at the rostral ventrolateral medulla. CONCLUSION: These results indicate that angiotensin-(1-7 triggers a complex pressor response at the rostral ventrolateral medulla that involves an increase in sympathetic tonus, release of vasopressin and possibly the inhibition of a vasodilatory mechanism.

  11. Oral Efficacy of Apigenin against Cutaneous Leishmaniasis: Involvement of Reactive Oxygen Species and Autophagy as a Mechanism of Action.

    Directory of Open Access Journals (Sweden)

    Fernanda Fonseca-Silva

    2016-02-01

    Full Text Available The treatment for leishmaniasis is currently based on pentavalent antimonials and amphotericin B; however, these drugs result in numerous adverse side effects. The lack of affordable therapy has necessitated the urgent development of new drugs that are efficacious, safe, and more accessible to patients. Natural products are a major source for the discovery of new and selective molecules for neglected diseases. In this paper, we evaluated the effect of apigenin on Leishmania amazonensis in vitro and in vivo and described the mechanism of action against intracellular amastigotes of L. amazonensis.Apigenin reduced the infection index in a dose-dependent manner, with IC50 values of 4.3 μM and a selectivity index of 18.2. Apigenin induced ROS production in the L. amazonensis-infected macrophage, and the effects were reversed by NAC and GSH. Additionally, apigenin induced an increase in the number of macrophages autophagosomes after the infection, surrounding the parasitophorous vacuole, suggestive of the involvement of host autophagy probably due to ROS generation induced by apigenin. Furthermore, apigenin treatment was also effective in vivo, demonstrating oral bioavailability and reduced parasitic loads without altering serological toxicity markers.In conclusion, our study suggests that apigenin exhibits leishmanicidal effects against L. amazonensis-infected macrophages. ROS production, as part of the mechanism of action, could occur through the increase in host autophagy and thereby promoting parasite death. Furthermore, our data suggest that apigenin is effective in the treatment of L. amazonensis-infected BALB/c mice by oral administration, without altering serological toxicity markers. The selective in vitro activity of apigenin, together with excellent theoretical predictions of oral availability, clear decreases in parasite load and lesion size, and no observed compromises to the overall health of the infected mice encourage us to supports

  12. Increased aerobic glycolysis through beta2 stimulation is a common mechanism involved in lactate formation during shock states.

    Science.gov (United States)

    Levy, Bruno; Desebbe, Olivier; Montemont, Chantal; Gibot, Sebastien

    2008-10-01

    During septic shock, muscle produces lactate by way of an exaggerated NaK-adenosine triphosphatase (ATPase)-stimulated aerobic glycolysis associated with epinephrine stimulation possibly through beta2 adrenoreceptor involvement. It therefore seems logical that a proportion of hyperlactatemia in low cardiac output states would be also related to this mechanism. Thus, in low-flow and normal-to-high-flow models of shock, we investigate (1) whether muscle produces lactate and (2) whether muscle lactate production is linked to beta2 adrenergic stimulation and Na+K+-ATPase. We locally modulated the adrenergic pathway and Na+K+-ATPase activity in male Wistar rats' skeletal muscle using microdialysis with nonselective and selective beta blockers and ouabain in different models of rodent shock (endotoxin, peritonitis, and hemorrhage). Blood flow at the probe site was evaluated by ethanol clearance. We measured the difference between muscle lactate and blood lactate concentration, with a positive gradient indicating muscle lactate or pyruvate production. Epinephrine levels were elevated in all shock groups. All models were associated with hypotension and marked hyperlactatemia. Muscle lactate concentrations were consistently higher than arterial levels, with a mean gradient of 2.5+/-0.3 in endotoxic shock, 2.1+/-0.2 mM in peritonitis group, and 0.9+/-0.2 mM in hemorrhagic shock (Pshock, 210+/-30 microM in peritonitis group, and 90+/-10 microM in hemorrhagic shock (Pshock mechanism. This demonstrates that lactate production during shock states is related, at least in part, to increased NaK-ATPase activity under beta2 stimulation. In shock state associated with a reduced or maintained blood flow, an important proportion of muscle lactate release is regulated by a beta2 receptor stimulation and not secondary to a reduced oxygen availability.

  13. Plant-plant-microbe mechanisms involved in soil-borne disease suppression on a maize and pepper intercropping system.

    Directory of Open Access Journals (Sweden)

    Min Yang

    Full Text Available BACKGROUND: Intercropping systems could increase crop diversity and avoid vulnerability to biotic stresses. Most studies have shown that intercropping can provide relief to crops against wind-dispersed pathogens. However, there was limited data on how the practice of intercropping help crops against soil-borne Phytophthora disease. PRINCIPAL FINDINGS: Compared to pepper monoculture, a large scale intercropping study of maize grown between pepper rows reduced disease levels of the soil-borne pepper Phytophthora blight. These reduced disease levels of Phytophthora in the intercropping system were correlated with the ability of maize plants to form a "root wall" that restricted the movement of Phytophthora capsici across rows. Experimentally, it was found that maize roots attracted the zoospores of P. capsici and then inhibited their growth. When maize plants were grown in close proximity to each other, the roots produced and secreted larger quantities of 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H-one (DIMBOA and 6-methoxy-2-benzoxazolinone (MBOA. Furthermore, MBOA, benzothiazole (BZO, and 2-(methylthio-benzothiazole (MBZO were identified in root exudates of maize and showed antimicrobial activity against P. capsici. CONCLUSIONS: Maize could form a "root wall" to restrict the spread of P. capsici across rows in maize and pepper intercropping systems. Antimicrobe compounds secreted by maize root were one of the factors that resulted in the inhibition of P. capsici. These results provide new insights into plant-plant-microbe mechanisms involved in intercropping systems.

  14. Heme iron from meat and risk of colorectal cancer: a meta-analysis and a review of the mechanisms involved.

    Science.gov (United States)

    Bastide, Nadia M; Pierre, Fabrice H F; Corpet, Denis E

    2011-02-01

    Red meat and processed meat intake is associated with a risk of colorectal cancer, a major cause of death in affluent countries. Epidemiological and experimental evidence supports the hypothesis that heme iron present in meat promotes colorectal cancer. This meta-analysis of prospective cohort studies of colon cancer reporting heme intake included 566,607 individuals and 4,734 cases of colon cancer. The relative risk of colon cancer was 1.18 (95% CI: 1.06-1.32) for subjects in the highest category of heme iron intake compared with those in the lowest category. Epidemiological data thus show a suggestive association between dietary heme and risk of colon cancer. The analysis of experimental studies in rats with chemically-induced colon cancer showed that dietary hemoglobin and red meat consistently promote aberrant crypt foci, a putative precancer lesion. The mechanism is not known, but heme iron has a catalytic effect on (i) the endogenous formation of carcinogenic N-nitroso compounds and (ii) the formation of cytotoxic and genotoxic aldehydes by lipoperoxidation. A review of evidence supporting these hypotheses suggests that both pathways are involved in heme iron toxicity.

  15. The Deceptively Simple N170 Reflects Network Information Processing Mechanisms Involving Visual Feature Coding and Transfer Across Hemispheres

    Science.gov (United States)

    Ince, Robin A. A.; Jaworska, Katarzyna; Gross, Joachim; Panzeri, Stefano; van Rijsbergen, Nicola J.; Rousselet, Guillaume A.; Schyns, Philippe G.

    2016-01-01

    A key to understanding visual cognition is to determine “where”, “when”, and “how” brain responses reflect the processing of the specific visual features that modulate categorization behavior—the “what”. The N170 is the earliest Event-Related Potential (ERP) that preferentially responds to faces. Here, we demonstrate that a paradigmatic shift is necessary to interpret the N170 as the product of an information processing network that dynamically codes and transfers face features across hemispheres, rather than as a local stimulus-driven event. Reverse-correlation methods coupled with information-theoretic analyses revealed that visibility of the eyes influences face detection behavior. The N170 initially reflects coding of the behaviorally relevant eye contralateral to the sensor, followed by a causal communication of the other eye from the other hemisphere. These findings demonstrate that the deceptively simple N170 ERP hides a complex network information processing mechanism involving initial coding and subsequent cross-hemispheric transfer of visual features. PMID:27550865

  16. Effects of benzo(a)pyrene on the skeletal development of Sebastiscus marmoratus embryos and the molecular mechanism involved

    Energy Technology Data Exchange (ETDEWEB)

    He Chengyong [Key Laboratory of Ministry of Education for Subtropical Wetland Ecosystem Research, School of Life Sciences, Xiamen University, Xiamen (China); Zuo Zhenghong [Key Laboratory of Ministry of Education for Subtropical Wetland Ecosystem Research, School of Life Sciences, Xiamen University, Xiamen (China); State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen (China); Shi Xiao; Li Ruixia; Chen Donglei; Huang Xin; Chen Yixin [Key Laboratory of Ministry of Education for Subtropical Wetland Ecosystem Research, School of Life Sciences, Xiamen University, Xiamen (China); Wang Chonggang, E-mail: cgwang@xmu.edu.cn [Key Laboratory of Ministry of Education for Subtropical Wetland Ecosystem Research, School of Life Sciences, Xiamen University, Xiamen (China); State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen (China)

    2011-01-25

    Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants, which have been known to be carcinogenic and teratogenic. However, the skeletal development toxicity of PAHs and the mechanism involved remain unclear. In fishes, the neurocranial and craniofacial skeleton develop as cartilage. The signaling molecules of hedgehog (Hh) family play crucial roles in regulating skeletal development. In the present study, rockfish (Sebastiscus marmoratus) embryos were exposed to benzo(a)pyrene (BaP) for 7 days at environmental levels (0.05, 0.5 and 5 nmol/L) which resulted in craniofacial skeleton deformities. BaP exposure reduced the cell proliferation activity in the craniofacial skeleton as detected by quantitative PCR and in situ hybridization. The expression of Sonic hedgehog (Shh), rather than Indian hedgehog (Ihh), was down-regulated in the craniofacial skeleton in the 0.5 and 5 nmol/L groups. Consistent with the Shh results, the expression of Ptch1 and Gli2 was decreased by BaP exposure and BMP4 was presented on changes in the 0.5 and 5 nmol/L groups. These results suggested that BaP could impair the expression and function of Shh signaling pathway, perturbing the proliferation of chondrocytes and so disturbing craniofacial skeletal development.

  17. Underlying mechanism of ASIC1a involved in acidosis-induced cytotoxicity in rat C6 glioma cells

    Institute of Scientific and Technical Information of China (English)

    Xie-chuan WENG; Jian-quan ZHENG; Jin LI; Wen-bin XIAO

    2007-01-01

    Aim:To investigate the underlying mechanism of acid-sensing ion channel (ASIC) la involved in the acidosis-induced cytotoxicity of rat C6 glioma cells. Methods:The stable ASICla-silenced C6 cells built with the RNA interference technology were confirmed by RT-PCR and Western blot analysis. Intracellular calcium ([Ca2+]i) in both the wild-type rat C6 glioma cells and the ASIC I a-silenced C6 cells were analyzed before and after acid application/exposure with the calcium imaging experiment. Results:The rapid extracellular pH drop induced the increase of [Ca2+]i in the wild-type C6 cells,but not in the ASICla-silenced C6 cells. During the prolonged acid exposure,[Ca2+]i was lower in the ASICla-silenced C6 cells than that in the control cells. Conclusion:The resultant toxicity of [Ca2+]i might contribute to the acidosis-induced cytotoxicity.

  18. Mechanisms involved in vitamin D mediated intestinal calcium absorption and in non-classical actions of vitamin D.

    Science.gov (United States)

    Christakos, Sylvia; Dhawan, Puneet; Ajibade, Dare; Benn, Bryan S; Feng, Jingjing; Joshi, Sneha S

    2010-07-01

    Recent studies in our laboratory using calbindin-D9k null mutant mice as well as mice lacking the 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) inducible epithelial calcium channel TRPV6 provide evidence for calbindin-D9k and TRPV6 independent regulation of active intestinal calcium absorption. These findings suggest that in the knock out (KO) mice there is compensation by another calcium channel or protein and that other novel factors are involved in 1,25(OH)2D3 mediated active intestinal calcium absorption. In addition, 1,25(OH)2D3 mediated paracellular transport of calcium may have contributed to the normalization of serum calcium in the null mutant mice. 1,25(OH)2D3 downregulates cadherin-17 and upregulates claudin-2 and claudin-12 in the intestine, suggesting that 1,25(OH)2D3, by regulating these epithelial cell junction proteins, can route calcium through the paracellular path. With regard to non-classical actions, 1,25(OH)2D3 has been reported to inhibit the proliferation of a number of malignant cells and to regulate adaptive as well as innate immunity. This article will review new developments related to the function and regulation of vitamin D target proteins in classical and non-classical vitamin D target tissues that have provided novel insight into mechanisms of vitamin D action.

  19. Gut microbiota-involved mechanisms in enhancing systemic exposure of ginsenosides by coexisting polysaccharides in ginseng decoction

    Science.gov (United States)

    Zhou, Shan-Shan; Xu, Jun; Zhu, He; Wu, Jie; Xu, Jin-Di; Yan, Ru; Li, Xiu-Yang; Liu, Huan-Huan; Duan, Su-Min; Wang, Zhuo; Chen, Hu-Biao; Shen, Hong; Li, Song-Lin

    2016-03-01

    Oral decoctions of traditional Chinese medicines (TCMs) serve for therapeutic and prophylactic management of diseases for centuries. Small molecules and polysaccharides are the dominant chemicals co-occurred in the TCM decoction. Small molecules are well-studied by multidisciplinary elaborations, whereas the role of polysaccharides remains largely elusive. Here we explore a gut microbiota-involved mechanism by which TCM polysaccharides restore the homeostasis of gut microbiota and consequently promote the systemic exposure of concomitant small molecules in the decoction. As a case study, ginseng polysaccharides and ginsenosides in Du-Shen-Tang, the decoction of ginseng, were investigated on an over-fatigue and acute cold stress model. The results indicated that ginseng polysaccharides improved intestinal metabolism and absorption of certain ginsenosides, meanwhile reinstated the perturbed holistic gut microbiota, and particularly enhanced the growth of Lactobacillus spp. and Bacteroides spp., two major metabolic bacteria of ginsenosides. By exploring the synergistic actions of polysaccharides with small molecules, these findings shed new light on scientization and rationalization of the classic TCM decoctions in human health care.

  20. Uptake and phloem transport of glucose-fipronil conjugate in Ricinus communis involve a carrier-mediated mechanism.

    Science.gov (United States)

    Wu, Han-Xiang; Yang, Wen; Zhang, Zhi-Xiang; Huang, Ting; Yao, Guang-Kai; Xu, Han-Hong

    2012-06-20

    Some compounds containing glucose are absorbed via the monosaccharide transporters of the plasma membrane. A glucose-fipronil conjugate, N-[3-cyano-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethyl)sulfinyl]-1H-pyrazol-5-yl]-1-(β-d-glucopyranosyl)-1H-1,2,3-triazole-4-methanamine (GTF), has been synthesized in our previous work. GTF exhibits moderate phloem mobility in Ricinus communis. In the current paper, we demonstrate that the uptake of GTF by Ricinus seedling cotyledon discs is partly mediated by an active carrier system (K(m)1 = 0.17 mM; V(max)1 = 2.2 nmol cm(-2) h(-1)). Four compounds [d-glucose, sucrose, phloridzin, and carbonyl cyanide m-chlorophenylhydrazone (CCCP)] were examined for their effect on GTF uptake. Phloridzin as well as CCCP markedly inhibit GTF uptake, and d-glucose weakly competes with it. The phloem transport of GTF in Ricinus seedlings is found to involve an active carrier-mediated mechanism that effectively contributes to the GTF phloem loading. The results prove that adding a glucose core is a reasonable and feasible approach to confer phloem mobility to fipronil by utilizing plant monosaccharide transporters.

  1. The predominant mechanism of intercellular calcium wave propagation changes during long-term culture of human osteoblast-like cells

    DEFF Research Database (Denmark)

    Henriksen, Zanne; Hiken, Jeffrey F; Steinberg, Thomas H;

    2006-01-01

    Intercellular calcium waves (ICW) are calcium transients that spread from cell to cell in response to different stimuli. We previously demonstrated that human osteoblast-like cells in culture propagate ICW in response to mechanical stimulation by two mechanisms. One mechanism involves autocrine...... assessed by video imaging of Fura-2 loaded cells after 1, 2 and 4 months culture. The P2Y2 receptor and the gap junction protein Cx43 were assessed by Western blot and real-time PCR. In resting conditions, P2Y mediated ICW prevailed and spread rapidly to about 13 cells. P2Y receptor desensitization by ATP......, but as cells differentiate in culture, gap-junction-mediated ICW become more prominent. These results suggest that P2Y receptor-mediated and gap junction-mediated mechanisms of intercellular calcium signaling may play different roles during differentiation of bone-forming cells....

  2. Melanoma cell-derived exosomes promote epithelial-mesenchymal transition in primary melanocytes through paracrine/autocrine signaling in the tumor microenvironment.

    Science.gov (United States)

    Xiao, Deyi; Barry, Samantha; Kmetz, Daniel; Egger, Michael; Pan, Jianmin; Rai, Shesh N; Qu, Jifu; McMasters, Kelly M; Hao, Hongying

    2016-07-01

    The tumor microenvironment is abundant with exosomes that are secreted by the cancer cells themselves. Exosomes are nanosized, organelle-like membranous structures that are increasingly being recognized as major contributors in the progression of malignant neoplasms. A critical element in melanoma progression is its propensity to metastasize, but little is known about how melanoma cell-derived exosomes modulate the microenvironment to optimize conditions for tumor progression and metastasis. Here, we provide evidence that melanoma cell-derived exosomes promote phenotype switching in primary melanocytes through paracrine/autocrine signaling. We found that the mitogen-activated protein kinase (MAPK) signaling pathway was activated during the exosome-mediated epithelial-to-mesenchymal transition (EMT)-resembling process, which promotes metastasis. Let-7i, an miRNA modulator of EMT, was also involved in this process. We further defined two other miRNA modulators of EMT (miR-191 and let-7a) in serum exosomes for differentiating stage I melanoma patients from non-melanoma subjects. These results provide the first strong molecular evidence that melanoma cell-derived exosomes promote the EMT-resembling process in the tumor microenvironment. Thus, novel strategies targeting EMT and modulating the tumor microenvironment may emerge as important approaches for the treatment of metastatic melanoma.

  3. A phosphatase-independent gain-of-function mutation in PTEN triggers aberrant cell growth in astrocytes through an autocrine IGF-1 loop.

    Science.gov (United States)

    Fernández, S; Genis, L; Torres-Alemán, I

    2014-08-07

    Loss-of-function mutations in the phosphatase PTEN (phosphatase and tensin homolog deleted on chromosome10) contribute to aberrant cell growth in part through upregulation of the mitogenic IGF-1/PI3K/Akt pathway. In turn, this pathway exerts a homeostatic feedback over PTEN. Using mutagenesis analysis to explore a possible impact of this mutual control on astrocyte growth, we found that truncation of the C-terminal region of PTEN (Δ51) associates with a marked increase in NFκB activity, a transcription factor overactivated in astrocyte tumors. Whereas mutations of PTEN are considered to lead to a loss-of-function, PTENΔ51, a truncation that comprises a region frequently mutated in human gliomas, displayed a neomorphic (gain-of-function) activity that was independent of its phosphatase activity. This gain-of-function of PTENΔ51 includes stimulation of IGF-1 synthesis through protein kinase A activation of the IGF-1 promoter. Increased IGF-1 originates an autocrine loop that activates Akt and NFκB. Constitutive activation of NFκB in PTENΔ51-expressing astrocytes leads to aberrant cell growth; astrocytes expressing this mutant PTEN generate colonies in vitro and tumors in vivo. Mutations converting a tumor suppressor such as PTEN into a tumor promoter through a gain-of-function involving IGF-1 production may further our understanding of the role played by this growth factor in glioma growth and help us define druggable targets for personalized therapy.

  4. Autocrine regulation of interferon gamma in mesenchymal stem cells plays a role in early osteoblastogenesis.

    Science.gov (United States)

    Duque, Gustavo; Huang, Dao Chao; Macoritto, Michael; Rivas, Daniel; Yang, Xian Fang; Ste-Marie, Louis Georges; Kremer, Richard

    2009-03-01

    Interferon (IFN)gamma is a strong inhibitor of osteoclast differentiation and activity. However, its role in osteoblastogenesis has not been carefully examined. Using microarray expression analysis, we found that several IFNgamma-inducible genes were upregulated during early phases of osteoblast differentiation of human mesenchymal stem cells (hMSCs). We therefore hypothesized that IFNgamma may play a role in this process. We first observed a strong and transient increase in IFNgamma production following hMSC induction to differentiate into osteoblasts. We next blocked this endogenous production using a knockdown approach with small interfering RNA and observed a strong inhibition of hMSC differentiation into osteoblasts with a concomitant decrease in Runx2, a factor indispensable for osteoblast development. Additionally, exogenous addition of IFNgamma accelerated hMSC differentiation into osteoblasts in a dose-dependent manner and induced higher levels of Runx2 expression during the early phase of differentiation. We next examined IFNgamma signaling in vivo in IFNgamma receptor 1 knockout (IFNgammaR1(-/-)) mice. Compared with their wild-type littermates, IFNgammaR1(-/-) mice exhibited a reduction in bone mineral density. As in the in vitro experiments, MSCs obtained from IFNgammaR1(-/-) mice showed a lower capacity to differentiate into osteoblasts. In summary, we demonstrate that the presence of IFNgamma plays an important role during the commitment of MSCs into the osteoblastic lineage both in vitro and in vivo, and that this process can be accelerated by exogenous addition of IFNgamma. These data therefore support a new role for IFNgamma as an autocrine regulator of hMSC differentiation and as a potential new target of bone-forming cells in vivo.

  5. Regulation of the expression of proto-oncogenes by autocrine embryotropins in the early mouse embryo.

    Science.gov (United States)

    Jin, Xing Liang; O'Neill, C

    2011-06-01

    Autocrine embryotropins act as survival signals for the preimplantation embryo. In this study we examined the role of Paf in the transcription of the key proto-oncogenes Bcl2 and Fos. Transcripts were detected in oocytes and some cohorts of zygotes but not in cohorts of 2-cell, 8-cell, and blastocyst stage embryos. Immunolocalization of BCL2 and FOS showed little staining in oocytes and zygotes but increased staining in the embryo from the 2-cell to blastocyst stage. Paf (37 nM) treatment of 2-cell embryos caused an alpha-amanitin (26 μM)-sensitive increase in Bcl2 and Fos transcripts 20 min after treatment that subsided by 40 min. This increase was blocked by inhibition of calcium (by BAPTA-AM) or phosphatidylinositol-3-kinase signaling (by LY294002). Paf challenge also caused increased staining of BCL2 and FOS. Increased staining of FOS required new protein synthesis that had a half-life of 2-4 h after Paf challenge. Only a small proportion (∼12%) of individual 2-cell embryos collected from the reproductive tract had detectable Bcl2 and Fos. This dichotomous pattern of transcript expression is consistent with the known periodic actions of Paf (which has a periodicity of ∼90 min) and the relatively short half-life of the resulting transcripts. A BCL2 antagonist (HA14-1) caused a dose-dependent decrease in the capacity of cultured zygotes to develop to morphological blastocysts, which was partially reversed by the simultaneous addition of Paf to medium. The results show that Paf induces periodic transient transcriptions of key proto-oncogenes that result in the persistent presence of the resulting proteins in the preimplantation phase of development.

  6. Metabotropic glutamate receptor 7 modulates the rewarding effects of cocaine in rats: involvement of a ventral pallidal GABAergic mechanism.

    Science.gov (United States)

    Li, Xia; Li, Jie; Peng, Xiao-Qing; Spiller, Krista; Gardner, Eliot L; Xi, Zheng-Xiong

    2009-06-01

    The metabotropic glutamate receptor 7 (mGluR7) has received much attention as a potential target for the treatment of epilepsy, major depression, and anxiety. In this study, we investigated the possible involvement of mGluR7 in cocaine reward in animal models of drug addiction. Pretreatment with the selective mGluR7 allosteric agonist N,N'-dibenzyhydryl-ethane-1,2-diamine dihydrochloride (AMN082; 1-20 mg/kg, i.p.) dose-dependently inhibited cocaine-induced enhancement of electrical brain-stimulation reward and intravenous cocaine self-administration under both fixed-ratio and progressive-ratio reinforcement conditions, but failed to alter either basal or cocaine-enhanced locomotion or oral sucrose self-administration, suggesting a specific inhibition of cocaine reward. Microinjections of AMN082 (1-5 microg/microl per side) into the nucleus accumbens (NAc) or ventral pallidum (VP), but not dorsal striatum, also inhibited cocaine self-administration in a dose-dependent manner. Intra-NAc or intra-VP co-administration of 6-(4-methoxyphenyl)-5-methyl-3-pyridin-4-ylisoxazolo[4,5-c]pyridin-4(5H)-one (MMPIP, 5 microg/microl per side), a selective mGluR7 allosteric antagonist, significantly blocked AMN082's action, suggesting an effect mediated by mGluR7 in these brain regions. In vivo microdialysis demonstrated that cocaine (10 mg/kg, i.p.) priming significantly elevated extracellular DA in the NAc or VP, while decreasing extracellular GABA in VP (but not in NAc). AMN082 pretreatment selectively blocked cocaine-induced changes in extracellular GABA, but not in DA, in both naive rats and cocaine self-administration rats. These data suggest: (1) mGluR7 is critically involved in cocaine's acute reinforcement; (2) GABA-, but not DA-, dependent mechanisms in the ventral striatopallidal pathway appear to underlie AMN082's actions; and (3) AMN082 or other mGluR7-selective agonists may be useful in the treatment of cocaine addiction.

  7. Genetic mechanisms involved in the evolution of the cephalopod camera eye revealed by transcriptomic and developmental studies

    Directory of Open Access Journals (Sweden)

    Ogura Atsushi

    2011-06-01

    Full Text Available Abstract Background Coleoid cephalopods (squids and octopuses have evolved a camera eye, the structure of which is very similar to that found in vertebrates and which is considered a classic example of convergent evolution. Other molluscs, however, possess mirror, pin-hole, or compound eyes, all of which differ from the camera eye in the degree of complexity of the eye structures and neurons participating in the visual circuit. Therefore, genes expressed in the cephalopod eye after divergence from the common molluscan ancestor could be involved in eye evolution through association with the acquisition of new structural components. To clarify the genetic mechanisms that contributed to the evolution of the cephalopod camera eye, we applied comprehensive transcriptomic analysis and conducted developmental validation of candidate genes involved in coleoid cephalopod eye evolution. Results We compared gene expression in the eyes of 6 molluscan (3 cephalopod and 3 non-cephalopod species and selected 5,707 genes as cephalopod camera eye-specific candidate genes on the basis of homology searches against 3 molluscan species without camera eyes. First, we confirmed the expression of these 5,707 genes in the cephalopod camera eye formation processes by developmental array analysis. Second, using molecular evolutionary (dN/dS analysis to detect positive selection in the cephalopod lineage, we identified 156 of these genes in which functions appeared to have changed after the divergence of cephalopods from the molluscan ancestor and which contributed to structural and functional diversification. Third, we selected 1,571 genes, expressed in the camera eyes of both cephalopods and vertebrates, which could have independently acquired a function related to eye development at the expression level. Finally, as experimental validation, we identified three functionally novel cephalopod camera eye genes related to optic lobe formation in cephalopods by in situ

  8. Binding of FGF2 to FGFR2 in an autocrine mode in trophectoderm cells is indispensable for mouse blastocyst formation through PKC-p38 pathway.

    Science.gov (United States)

    Yang, Jing; Zhang, Dan; Yu, Ying; Zhang, Run-Ju; Hu, Xiao-Ling; Huang, He-Feng; Lu, Yong-Chao

    2015-01-01

    Fibroblast growth factors (FGF1, FGF2 and FGF4) and fibroblast growth factor receptors (FGFR1, FGFR2, FGFR3 and FGFR4) have been reported to be expressed in preimplantation embryos and be required for their development. However, the functions of these molecules in trophectoderm cells (TEs) that lead to the formation of the blastocyst as well as the underlying mechanism have not been elucidated. The present study has demonstrated for the first time that endogenous FGF2 secreted by TEs can regulate protein expression and distribution in TEs via the FGFR2-mediated activation of PKC and p38, which are important for the development of expanded blastocysts. This finding provides the first explanation for the long-observed phenomenon that only high concentrations of exogenous FGFs have effects on embryonic development, but in vivo the amount of endogenous FGFs are trace. Besides, the present results suggest that FGF2/FGFR2 may act in an autocrine fashion and activate the downstream PKC/p38 pathway in TEs during expanded blastocyst formation.

  9. Mechanisms involved in the anti-inflammatory action of a polysulfated fraction from Gracilaria cornea in rats.

    Directory of Open Access Journals (Sweden)

    Chistiane Oliveira Coura

    Full Text Available The anti-inflammatory mechanisms of the sulfated polysaccharidic fraction obtained from red marine alga Gracilaria cornea (Gc-FI were investigated using a paw edema model induced in rats by different inflammatory agents (carrageenan, dextran, serotonin, bradykinin, compound 48/80 or L-arginine. Gc-FI at the doses of 3, 9 or 27 mg/kg, subcutaneously--s.c., significantly inhibited rat paw edema induced by carrageenan and dextran, as confirmed by myeloperoxidase and Evans' blue assessments, respectively. Gc-FI (9 mg/kg, s.c. inhibited rat paw edema induced by histamine, compound 48/80 and L-arginine. Additionally, Gc-FI (9 mg/kg, s.c. inhibited Cg-induced edema in animals with intact mast cells but did not inhibit that with degranulated mast cells by compound 48/80, revealing a protective role on mast cell membranes. Gc-FI down-regulated the IL-1β, TNF-α and COX-2 mRNA and protein levels compared with those of the carrageenan group, based on qRT-PCR and immunohistochemistry analyses. After inhibition with ZnPP IX, a specific heme oxygenase-1 (HO-1 inhibitor, the anti-inflammatory effect of Gc-FI was not observed in Cg-induced paw edema, suggesting that the anti-inflammatory effect of Gc-FI is, in part, dependent on the integrity of the HO-1 pathway. Gc-FI can target a combination of multiple points involved in inflammatory phenomena.

  10. Mechanisms involved in the anti-inflammatory action of a polysulfated fraction from Gracilaria cornea in rats.

    Science.gov (United States)

    Coura, Chistiane Oliveira; Souza, Ricardo Basto; Rodrigues, José Ariévilo Gurgel; Vanderlei, Edfranck de Sousa Oliveira; de Araújo, Ianna Wivianne Fernandes; Ribeiro, Natássia Albuquerque; Frota, Annyta Fernandes; Ribeiro, Kátia Alves; Chaves, Hellíada Vasconcelos; Pereira, Karuza Maria Alves; da Cunha, Rodrigo Maranguape Silva; Bezerra, Mirna Marques; Benevides, Norma Maria Barros

    2015-01-01

    The anti-inflammatory mechanisms of the sulfated polysaccharidic fraction obtained from red marine alga Gracilaria cornea (Gc-FI) were investigated using a paw edema model induced in rats by different inflammatory agents (carrageenan, dextran, serotonin, bradykinin, compound 48/80 or L-arginine). Gc-FI at the doses of 3, 9 or 27 mg/kg, subcutaneously--s.c., significantly inhibited rat paw edema induced by carrageenan and dextran, as confirmed by myeloperoxidase and Evans' blue assessments, respectively. Gc-FI (9 mg/kg, s.c.) inhibited rat paw edema induced by histamine, compound 48/80 and L-arginine. Additionally, Gc-FI (9 mg/kg, s.c.) inhibited Cg-induced edema in animals with intact mast cells but did not inhibit that with degranulated mast cells by compound 48/80, revealing a protective role on mast cell membranes. Gc-FI down-regulated the IL-1β, TNF-α and COX-2 mRNA and protein levels compared with those of the carrageenan group, based on qRT-PCR and immunohistochemistry analyses. After inhibition with ZnPP IX, a specific heme oxygenase-1 (HO-1) inhibitor, the anti-inflammatory effect of Gc-FI was not observed in Cg-induced paw edema, suggesting that the anti-inflammatory effect of Gc-FI is, in part, dependent on the integrity of the HO-1 pathway. Gc-FI can target a combination of multiple points involved in inflammatory phenomena.

  11. Mast cells phagocyte Candida albicans and produce nitric oxide by mechanisms involving TLR2 and Dectin-1.

    Science.gov (United States)

    Pinke, Karen Henriette; Lima, Heliton Gustavo de; Cunha, Fernando Queiroz; Lara, Vanessa Soares

    2016-02-01

    Candida albicans (C. albicans) is a fungus commonly found in the human mucosa, which may cause superficial and systemic infections, especially in immunosuppression. Until now, the main actors in the defense against this fungus are the epithelial cells, neutrophils, macrophages/monocytes and dendritic cells. However, mast cells are strategically located to play a first line of anti-Candida defense and it has appropriate mechanisms to do it. As with other cells, the recognition of C. albicans occurs meanly via TLR2 and Dectin-1. We assess the TLR2/Dectin-1 involvement in phagocytosis and production of nitric oxide (NO) and reactive oxygen species (ROS) by mast cells challenged with C. albicans. Bone marrow-derived mast cells (MC) from wild type (Wt) or knockout (TLR2-/-) mice C57BL/6 were subjected to in vitro Dectin-1 blockade. After challenged with FITC-labeled C. albicans or zymosan, phagocytosis was analyzed by microscopy. The intracellular production of NO and ROS was measured by DAF-FM diacetate and CellROX Deep/Red Reagent kits. The nitrite formation and hydrogen peroxide release were analyzed by Griess reaction and Amplex Red Hydrogen Peroxide/Peroxidase Assay Kit. Wt/MC phagocytose C. albicans with production of intracellular NO, but not ROS. Moreover, increased levels of nitrite were also observed. The absence and/or blockade of TLR2/Dectin-1 caused significant decreased in C. albicans phagocytosis and NO production. Our results showed that mast cells are able to phagocytose and produce NO against C. albicans via TLR2/Dectin-1. Therefore, mast cells could be important during the course of Candida infection and as a therapeutic target.

  12. Slimmer or fertile? Pharmacological mechanisms involved in reduced sperm quality and fertility in rats exposed to the anorexigen sibutramine.

    Directory of Open Access Journals (Sweden)

    Cibele S Borges

    Full Text Available Sperm acquire motility and fertility capacity during epididymal transit, under the control of androgens and sympathetic innervations. It is already known that the acceleration of epididymal sperm transit time can lead to lower sperm quality. In a previous work we showed that rats exposed to the anorexigen sibutramine, a non-selective serotonin-norepinephrine reuptake inhibitor, presented faster sperm transit time, lower epididymal sperm reserves and potentiation of the tension of epididymal duct to norepinephrine exposed acutely in vitro to sibutramine. In the present work we aimed to further investigate pharmacological mechanisms involved in these alterations and the impact on rat sperm quality. For this, adult male Wistar rats were treated with sibutramine (10 mg/kg/day or vehicle for 30 days. Sibutramine decreased final body, seminal vesicle, ventral prostate and epididymal weights, as well as sperm transit time in the epididymal cauda. On the contrary of the in vitro pharmacological assays, in which sibutramine was added directly to the bath containing strips of distal epididymal cauda, the ductal tension was not altered after in vivo sub-chronic exposure to sibutramine. However, there is pharmacological evidence that the endogenous epididymal norepinephrine reserves were reduced in these animals. It was also shown that the decrease in prostate weight can be related to increased tension developed of the gland, due to sibutramine sympathomimetic effects. In addition, our results showed reduced sperm quality after in utero artificial insemination, a more sensitive procedure to assess fertility in rodents. The epididymal norepinephrine depletion exerted by sibutramine, associated with decreases in sperm transit time, quantity and quality, leading to reduced fertility in this experimental model, reinforces the concerns about the possible impact on fertility of man taking sibutramine as well as other non-selective serotonin

  13. Antimanic-like activity of candesartan in mice: Possible involvement of antioxidant, anti-inflammatory and neurotrophic mechanisms.

    Science.gov (United States)

    de Souza Gomes, Júlia Ariana; de Souza, Greicy Coelho; Berk, Michael; Cavalcante, Lígia Menezes; de Sousa, Francisca Cléa F; Budni, Josiane; de Lucena, David Freitas; Quevedo, João; Carvalho, André F; Macêdo, Danielle

    2015-11-01

    Activation of the brain angiotensin II type 1 receptor (AT1R) triggers pro-oxidant and pro-inflammatory mechanisms which are involved in the neurobiology of bipolar disorder (BD). Candesartan (CDS) is an AT1 receptor antagonist with potential neuroprotective properties. Herein we investigated CDS effects against oxidative, neurotrophic inflammatory and cognitive effects of amphetamine (AMPH)-induced mania. In the reversal protocol adult mice were given AMPH 2 mg/kg i.p. or saline and between days 8 and 14 received CDS 0.1, 0.3 or 1 mg/kg orally, lithium (Li) 47.5 mg/kg i.p., or saline. In the prevention treatment, mice were pretreated with CDS, Li or saline prior to AMPH. Locomotor activity and working memory performance were assessed. Glutathione (GSH), thiobarbituric acid-reactive substance (TBARS) and TNF-α levels were evaluated in the hippocampus (HC) and cerebellar vermis (CV). Brain-derived neurotrophic factor (BDNF) and glycogen synthase kinase 3-beta (GSK-3beta) levels were measured in the HC. CDS and Li prevented and reversed the AMPH-induced increases in locomotor activity. Only CDS prevented and reversed AMPH-induced working memory deficits. CDS prevented AMPH-induced alterations in GSH (HC and CV), TBARS (HC and CV), TNF-α (HC and CV) and BDNF (HC) levels. Li prevented alterations in BDNF and phospho-Ser9-GSK3beta. CDS reversed AMPH-induced alterations in GSH (HC and CV), TBARS (HC), TNF-α (CV) and BDNF levels. Li reversed AMPH-induced alterations in TNF-α (HC and CV) and BDNF (HC) levels. CDS is effective in reversing and preventing AMPH-induced behavioral and biochemical alterations, providing a rationale for the design of clinical trials investigating CDS׳s possible therapeutic effects.

  14. The Ang II-induced growth of vascular smooth muscle cells involves a phospholipase D-mediated signaling mechanism.

    Science.gov (United States)

    Freeman, E J

    2000-02-15

    Angiotensin (Ang) II acts as a mitogen in vascular smooth muscle cells (VSMC) via the activation of multiple signaling cascades, including phospholipase C, tyrosine kinase, and mitogen-activated protein kinase pathways. However, increasing evidence supports signal-activated phospholipases A(2) and D (PLD) as additional mechanisms. Stimulation of PLD results in phosphatidic acid (PA) formation, and PA has been linked to cell growth. However, the direct involvement of PA or its metabolite diacylglycerol (DAG) in Ang II-induced growth is unclear. PLD activity was measured in cultured rat VSMC prelabeled with [(3)H]oleic acid, while the incorporation of [(3)H]thymidine was used to monitor growth. We have previously reported the Ang II-dependent, AT(1)-coupled stimulation of PLD and growth in VSMC. Here, we show that Ang II (100 nM) and exogenous PLD (0.1-100 units/mL; Streptomyces chromofuscus) stimulated thymidine incorporation (43-208% above control). PA (100 nM-1 microM) also increased thymidine incorporation to 135% of control. Propranolol (100 nM-10 microM), which inhibits PA phosphohydrolase, blocked the growth stimulated by Ang II, PLD, or PA by as much as 95%, an effect not shared by other beta-adrenergic antagonists. Propranolol also increased the production of PA in the presence of Ang II by 320% and reduced DAG and arachidonic acid (AA) accumulation. The DAG lipase inhibitor RHC-80267 (1-10 microM) increased Ang II-induced DAG production, while attenuating thymidine incorporation and release of AA. Thus, it appears that activation of PLD, formation of PA, conversion of PA to DAG, and metabolism of DAG comprise an important signaling cascade in Ang II-induced growth of VSMC.

  15. The asymmetric binding of PGC-1α to the ERRα and ERRγ nuclear receptor homodimers involves a similar recognition mechanism.

    Directory of Open Access Journals (Sweden)

    Maria Takacs

    Full Text Available BACKGROUND: PGC-1α is a crucial regulator of cellular metabolism and energy homeostasis that functionally acts together with the estrogen-related receptors (ERRα and ERRγ in the regulation of mitochondrial and metabolic gene networks. Dimerization of the ERRs is a pre-requisite for interactions with PGC-1α and other coactivators, eventually leading to transactivation. It was suggested recently (Devarakonda et al that PGC-1α binds in a strikingly different manner to ERRγ ligand-binding domains (LBDs compared to its mode of binding to ERRα and other nuclear receptors (NRs, where it interacts directly with the two ERRγ homodimer subunits. METHODS/PRINCIPAL FINDINGS: Here, we show that PGC-1α receptor interacting domain (RID binds in an almost identical manner to ERRα and ERRγ homodimers. Microscale thermophoresis demonstrated that the interactions between PGC-1α RID and ERR LBDs involve a single receptor subunit through high-affinity, ERR-specific L3 and low-affinity L2 interactions. NMR studies further defined the limits of PGC-1α RID that interacts with ERRs. Consistent with these findings, the solution structures of PGC-1α/ERRα LBDs and PGC-1α/ERRγ LBDs complexes share an identical architecture with an asymmetric binding of PGC-1α to homodimeric ERR. CONCLUSIONS/SIGNIFICANCE: These studies provide the molecular determinants for the specificity of interactions between PGC-1α and the ERRs, whereby negative cooperativity prevails in the binding of the coactivators to these receptors. Our work indicates that allosteric regulation may be a general mechanism controlling the binding of the coactivators to homodimers.

  16. Signaling Pathways Involved in Cardiac Hypertrophy

    Institute of Scientific and Technical Information of China (English)

    Tao Zewei; Li Longgui

    2006-01-01

    Cardiac hypertrophy is the heart's response to a variety of extrinsic and intrinsic stimuli that impose increased biomechanical stress.Traditionally, it has been considered a beneficial mechanism; however, sustained hypertrophy has been associated with a significant increase in the risk of cardiovascular disease and mortality. Delineating intracellular signaling pathways involved in the different aspects of cardiac hypertrophy will permit future improvements in potential targets for therapeutic intervention. Generally, there are two types of cardiac hypertrophies, adaptive hypertrophy, including eutrophy (normal growth) and physiological hypertrophy (growth induced by physical conditioning), and maladaptive hypertrophy, including pathologic or reactive hypertrophy (growth induced by pathologic stimuli) and hypertrophic growth caused by genetic mutations affecting sarcomeric or cytoskeletal proteins. Accumulating observations from animal models and human patients have identified a number of intracellular signaling pathways that characterized as important transducers of the hypertrophic response,including calcineurin/nuclear factor of activated Tcells, phosphoinositide 3-kinases/Akt (PI3Ks/Akt),G protein-coupled receptors, small G proteins,MAPK, PKCs, Gp130/STAT'3, Na+/H+ exchanger,peroxisome proliferator-activated receptors, myocyte enhancer factor 2/histone deacetylases, and many others. Furthermore, recent evidence suggests that adaptive cardiac hypertrophy is regulated in large part by the growth hormone/insulin-like growth factors axis via signaling through the PI3K/Akt pathway. In contrast, pathological or reactive hypertrophy is triggered by autocrine and paracrine neurohormonal factors released during biomechanical stress that signal through the Gq/phosphorlipase C pathway, leading to an increase in cytosolic calcium and activation of PKC.

  17. Autocrine VEGF-VEGFR2-Neuropilin-1 signaling promotes glioma stem-like cell viability and tumor growth

    DEFF Research Database (Denmark)

    Hamerlik, Petra; Lathia, Justin D; Rasmussen, Rikke;

    2012-01-01

    glioma stem-like cells (GSCs), whose viability, self-renewal, and tumorigenicity rely, at least in part, on signaling through the VEGF-VEGFR2-Neuropilin-1 (NRP1) axis. We find that the limited impact of bevacizumab-mediated VEGF blockage may reflect ongoing autocrine signaling through VEGF-VEGFR2-NRP1......, which is associated with VEGFR2-NRP1 recycling and a pool of active VEGFR2 within a cytosolic compartment of a subset of human GBM cells. Whereas bevacizumab failed to inhibit prosurvival effects of VEGFR2-mediated signaling, GSC viability under unperturbed or radiation-evoked stress conditions...

  18. Low prosocial attachment, involvement with drug-using peers, and adolescent drug use: a longitudinal examination of mediational mechanisms.

    Science.gov (United States)

    Henry, Kimberly L

    2008-06-01

    The process of disengagement from prosocial entities (e.g., family and school) and either simultaneous or subsequent engagement with antisocial entities (e.g., friends who use drugs) is a critical contributor to adolescent drug use and delinquency. This study provides a series of formal mediation tests to demonstrate the relationship between poor family attachment, poor school attachment, involvement with friends who use drugs, and a student's own use of drugs. Results indicate that poor family attachment exerts its effect on drug use through poor school attachment and involvement with friends who use drugs. In addition, poor school attachment exerts its effect on drug use through involvement with friends who use drugs. The results of this study corroborate theories that suggest disengagement from prosocial entities is associated with involvement with antisocial entities and eventual involvement in drug use. Implications for prevention strategies are discussed.

  19. Thermodynamic analysis of ionizable groups involved in the catalytic mechanism of human matrix metalloproteinase 7 (MMP-7).

    Science.gov (United States)

    Takeharu, Hitoshi; Yasukawa, Kiyoshi; Inouye, Kuniyo

    2011-12-01

    Human matrix metalloproteinase 7 (MMP-7) exhibits a broad bell-shaped pH-dependence with the acidic and alkaline pK(e) (pK(e1) and pK(e2)) values of about 4 and 10. In this study, we estimated the ionizable groups involved in its catalytic mechanism by thermodynamic analysis. pK(a) of side chains of L-Asp, L-Glu, L-His, L-Cys, L-Tyr, L-Lys, and L-Arg at 25-45°C were determined by the pH titration of amino-acid solutions, from which their enthalpy changes, ∆H°, of deprotonation were calculated. pK(e1) and pK(e2) of MMP-7 at 15-45°C were determined in the hydrolysis of (7-methoxycoumarin-4-yl)acetyl-L-Pro-L-Leu-Gly-L-Leu-[N(3)-(2,4-dinitrophenyl)-L-2,3-diaminopropionyl]-L-Ala-L-Arg-NH(2), from which ∆H(o) for pK(e1) and pK(e2) was calculated. The ∆H(o) for pK(e1) (-20.6±6.1kJmol(-1)) was similar to that for L-Glu (-23.6±5.8kJmol(-1)), and the ∆H(o) for pK(e2) (89.9±4.0kJmol(-1)) was similar to those for L-Arg (87.6±5.5kJmol(-1)) and L-Lys (70.4±4.4kJmol(-1)). The mutation of the active-site residue Glu198 into Ala completely abolished the activity, suggesting that Glu198 is the ionizable group for pK(e1). On the other hand, no arginine or lysine residues are found in the active site of MMP-7. We proposed a possibility that a protein-bound water is the ionizable group for pK(e2).

  20. Study of the mechanisms involved in the vasorelaxation induced by (−)-epigallocatechin-3-gallate in rat aorta

    Science.gov (United States)

    Álvarez, Ezequiel; Campos-Toimil, Manuel; Justiniano-Basaran, Hélène; Lugnier, Claire; Orallo, Francisco

    2005-01-01

    This study investigated several mechanisms involved in the vasorelaxant effects of (−)-epigallocatechin-3-gallate (EGCG). EGCG (1 μM–1 mM) concentration dependently relaxed, after a transient increase in tension, contractions induced by noradrenaline (NA, 1 μM), high extracellular KCl (60 mM), or phorbol 12-myristate 13-acetate (PMA, 1 μM) in intact rat aortic rings. In a Ca2+-free solution, EGCG (1 μM–1 mM) relaxed 1 μM PMA-induced contractions, without previous transient contraction. However, EGCG (1 μM–1 mM) did not affect the 1 μM okadaic acid-induced contractions. Removal of endothelium and/or pretreatment with glibenclamide (10 μM), tetraethylammonium (2 mM) or charybdotoxin (100 nM) plus apamin (500 nM) did not modify the vasorelaxant effects of EGCG. In addition, EGCG noncompetitively antagonized the contractions induced by NA (in 1.5 mM Ca2+-containing solution) and Ca2+ (in depolarizing Ca2+-free high KCl 60 mM solution). In rat aortic smooth muscle cells (RASMC), EGCG (100 μM) reduced increases in cytosolic free Ca2+ concentration ([Ca2+]i) induced by angiotensin II (ANG II, 100 nM) and KCl (60 mM) in 1.5 mM CaCl2-containing solution and by ANG II (100 nM) in the absence of extracellular Ca2+. In RASMC, EGCG (100 μM) did not modify basal generation of cAMP or cGMP, but significantly reversed the inhibitory effects of NA (1 μM) and high KCl (60 mM) on cAMP and cGMP production. EGCG inhibited the enzymatic activity of all the cyclic nucleotide PDE isoenzymes present in vascular tissue, being more effective on PDE2 (IC50∼17) and on PDE1 (IC50∼25). Our results suggest that the vasorelaxant effects of EGCG in rat aorta are mediated, at least in part, by an inhibition of PDE activity, and the subsequent increase in cyclic nucleotide levels in RASMC, which, in turn, can reduce agonist- or high KCl concentration-induced increases in [Ca2+]i. PMID:16299547

  1. Identification of mechanisms involved in the relaxation of rabbit cavernous smooth muscle by a new nitric oxide donor ruthenium compound

    Directory of Open Access Journals (Sweden)

    João Batista Gadelha de Cerqueira

    2012-10-01

    Full Text Available PURPOSE: The aim of this study was to evaluate the relaxation in vitro of cavernous smooth muscle induced by a new NO donor of the complex nitrosil-ruthenium, named trans-[Ru(NH34(caffeine(NO]C13 (Rut-Caf and sodium nitroprusside (SNP. MATERIALS AND METHODS: The tissues, immersed in isolated bath systems, were pre-contracted with phenilephrine (PE (1 µM and then concentration-response curves (10-12 - 10-4 M were obtained. To clarify the mechanism of action involved, it was added to the baths ODQ (10 µM, 30 µM, oxyhemoglobin (10 µM, L-cysteine (100 µM, hydroxicobalamine (100 µM, glibenclamide, iberotoxin and apamine. Tissue samples were frozen in liquid nitrogen to measure the amount of cGMP and cAMP produced. RESULTS: The substances provoked significant relaxation of the cavernous smooth muscle. Both Rut-Caf and SNP determined dose-dependent relaxation with similar potency (pEC50 and maximum effect (Emax. The substances showed activity through activation of the soluble guanylyl cyclase (sGC, because the relaxations were inhibited by ODQ. Oxyhemoglobin significantly diminished the relaxation effect of the substances. L-cysteine failed to modify the relaxations caused by the agents. Hydroxicobalamine significantly diminished the relaxation effect of Rut-Caf. Glibenclamide significantly increased the efficacy of Rut-Caf (pEC50 4.09 x 7.09. There were no alterations of potency or maximum effect of the substances with the addition of the other ion channel blockers. Rut-Caf induced production of significant amounts of cGMP and cAMP during the relaxation process. CONCLUSIONS: In conclusion, Rut-Caf causes relaxation of smooth muscle of corpus cavernosum by means of activation of sGC with intracellular production of cGMP and cAMP; and also by release of NO in the intracellular environment. Rut-Caf releases the NO free radical and it does not act directly on the potassium ion channels.

  2. Connective tissue growth factor and β-catenin constitute an autocrine loop for activation in rat sarcomatoid mesothelioma.

    Science.gov (United States)

    Jiang, Li; Yamashita, Yoriko; Chew, Shan-Hwu; Akatsuka, Shinya; Ukai, Shun; Wang, Shenqi; Nagai, Hirotaka; Okazaki, Yasumasa; Takahashi, Takashi; Toyokuni, Shinya

    2014-08-01

    Due to the formerly widespread use of asbestos, malignant mesothelioma (MM) is increasingly frequent worldwide. MM is classified into epithelioid (EM), sarcomatoid (SM), and biphasic subtypes. SM is less common than EM but is recognized as the most aggressive type of MM, and these patients have a poor prognosis. To identify genes responsible for the aggressiveness of SM, we induced EM and SM in rats, using asbestos, and compared their transcriptomes. Based on the results, we focused on connective tissue growth factor (Ctgf), whose expression was significantly increased in SM compared with EM; EM itself exhibited an increased expression of Ctgf compared with normal mesothelium. Particularly in SM, Ctgf was a major regulator of MM proliferation and invasion through activation of the β-catenin-TCF-LEF signalling pathway, which is autocrine and formed a positive feedback loop via LRP6 as a receptor for secreted Ctgf. High Ctgf expression also played a role in the epithelial-mesenchymal transition in MM. Furthermore, Ctgf is a novel serum biomarker for both early diagnosis and determining the MM prognosis in rats. These data link Ctgf to SM through the LRP6-GSK3β-β-catenin-TCF-Ctgf autocrine axis and suggest Ctgf as a therapeutic target.

  3. Autocrine and paracrine Shh signaling are necessary for tooth morphogenesis, but not tooth replacement in snakes and lizards (Squamata).

    Science.gov (United States)

    Handrigan, Gregory R; Richman, Joy M

    2010-01-01

    Here we study the role of Shh signaling in tooth morphogenesis and successional tooth initiation in snakes and lizards (Squamata). By characterizing the expression of Shh pathway receptor Ptc1 in the developing dentitions of three species (Eublepharis macularius, Python regius, and Pogona vitticeps) and by performing gain- and loss-of-function experiments, we demonstrate that Shh signaling is active in the squamate tooth bud and is required for its normal morphogenesis. Shh apparently mediates tooth morphogenesis by separate paracrine- and autocrine-mediated functions. According to this model, paracrine Shh signaling induces cell proliferation in the cervical loop, outer enamel epithelium, and dental papilla. Autocrine signaling within the stellate reticulum instead appears to regulate cell survival. By treating squamate dental explants with Hh antagonist cyclopamine, we induced tooth phenotypes that closely resemble the morphological and differentiation defects of vestigial, first-generation teeth in the bearded dragon P. vitticeps. Our finding that these vestigial teeth are deficient in epithelial Shh signaling further corroborates that Shh is needed for the normal development of teeth in snakes and lizards. Finally, in this study, we definitively refute a role for Shh signaling in successional dental lamina formation and conclude that other pathways regulate tooth replacement in squamates.

  4. Glucose stimulates neurotensin secretion from the rat small intestine by mechanisms involving SGLT1 and GLUT2 leading to cell depolarization and calcium influx

    DEFF Research Database (Denmark)

    Kuhre, Rune Ehrenreich; Bechmann, Louise Ellegaard; Hartmann, Bolette

    2015-01-01

    , but the mechanisms involved are not well understood. Here, we show that rats express NT in the gut and that glucose gavage stimulates secretion similarly to oral glucose in humans. Therefore, we conducted experiments on isolated perfused rat small intestine with a view to characterize the cellular pathways...

  5. Molecular mechanisms involved in the inhibition of MDA-MB-435 breast cancer cells by phenolic acids from the red-flesh peach BY00P6653

    Science.gov (United States)

    A wide variety of fruits and vegetables extracts have been shown to protect against cancer cell growth in vitro. Increasing evidence suggests that phenolics compounds found in fruits and vegetables may have anticancer properties. However, the molecular mechanisms involved in the anti-proliferative...

  6. Salvianolic Acid B inhibits platelet adhesion under conditions of flow by a mechanism involving the collagen receptor alpha 2 beta 1

    NARCIS (Netherlands)

    Wu, Ya Ping; Zhao, Xiao Min; Pan, Shao Dong; Guo, De An; Wei, Ran; Han, Ji Ju; Kainoh, Mie; Xia, Zuo Li; de Groot, Philip G.; Lisman, Ton

    2008-01-01

    Salvianolic acid B (SAB) is a component of Danshen, a herb widely used in Chinese medicine, and was previously shown to exert a number of biological activities including inhibition of platelet function, but the exact mechanisms involved are unclear. SAB dose-dependently inhibited platelet deposition

  7. Cutting the Loops of Depression: a System Dynamics Representation of the Feedback Mechanisms Involved in Depression Development

    NARCIS (Netherlands)

    Herrera, D.; Bleijenbergh, I.L.

    2016-01-01

    Depression is a complex illness that involves the instability of biological and psychological structures in an individual. These disturbances make a depressed person to be affected in the personal relationships within his social circles and to be unable to fulfill normal daily activities as expected

  8. Autocrine regulation of TGF-β1-induced cell migration by exocytosis of ATP and activation of P2 receptors in human lung cancer cells.

    Science.gov (United States)

    Takai, Erina; Tsukimoto, Mitsutoshi; Harada, Hitoshi; Sawada, Keisuke; Moriyama, Yoshinori; Kojima, Shuji

    2012-11-01

    TGF-β1 plays a key role in cancer progression through induction of various biological effects, including cell migration. Extracellular nucleotides, such as ATP, released from cells play a role in signaling through activation of P2 receptors. We show here that exocytosis of ATP followed by activation of P2 receptors play a key role in TGF-β1-induced actin remodeling associated with cell migration. Treatment with TGF-β1 facilitated migration of human lung cancer A549 cells, which was blocked by pretreatment with ecto-nucleotidase and P2 receptor antagonists. ATP and P2 agonists facilitated cell migration. TGF-β1-induced actin remodeling, which contributes to cell migration, was also suppressed by pretreatment with ecto-nucleotidase and P2 receptor antagonists. Knockdown of P2X7 receptor suppressed TGF-β1-induced migration and actin remodeling. These results indicate the involvement of TGF-β1-induced ATP release in cell migration, at least in part, through activation of P2X7 receptors. TGF-β1 caused release of ATP from A549 cells within 10 minutes. Both ATP-enriched vesicles and expression of a vesicular nucleotide transporter (VNUT) SLC17A9, which is responsible for exocytosis of ATP, were found in cytosol of A549 cells. TGF-β1 failed to induce release of ATP from SLC17A9-knockdown cells. TGF-β1-induced cell migration and actin remodeling were also decreased in SLC17A9-knockdown cells. These results suggest the importance of exocytosis of ATP in cell migration. We conclude that autocrine signaling through exocytosis of ATP and activation of P2 receptors is required for the amplification of TGF-β1-induced migration of lung cancer cells.

  9. Expression of autocrine prolactin and the short isoform of prolactin receptor are associated with inflammatory response and apoptosis in monocytes stimulated with Mycobacterium bovis proteins.

    Science.gov (United States)

    López-Rincón, Gonzalo; Mancilla, Raúl; Pereira-Suárez, Ana L; Martínez-Neri, Priscila A; Ochoa-Zarzosa, Alejandra; Muñoz-Valle, José Francisco; Estrada-Chávez, Ciro

    2015-06-01

    Increased levels of prolactin (PRL) have recently been associated with carcinogenesis and the exacerbation of autoimmune diseases, and might be involved in the progression of tuberculosis (TB). To investigate the relationship between PRL and prolactin receptor (PRLr) expression with inflammatory response and apoptosis in monocytes, we used THP-1 cells stimulated with antigens of the Mycobacterium bovis AN5 strain culture filtrate protein (CFP-M. bovis). Western blot (WB), real-time Polymerase chain reaction (PCR), and immunocytochemistry were performed to identify both PRL and PRLr molecules. PRL bioactivity and proinflammatory cytokine detection were assessed. The results showed that PRL and PRLr messenger RNA (mRNA) were synthesized in THP-1 monocytes induced with CFP-M. bovis at peaks of 176- and 404-fold, respectively. PRL forms of 60 and 80kDa and PRLr isoforms of 40, 50, and 65kDa were also identified as time-dependent, while 60-kDa PRL, as well as 40-, and 50-kDa PRLr, were found as soluble forms in culture media and later in the nucleus of THP-1 monocytes. PRL of 60kDa released by monocytes exhibited bioactivity in Nb2 cells, and both synthesized PRL and synthesized PRLr were related with nitrite and proinflammatory cytokine levels proapoptotic activity in CFP-M. bovis-induced monocytes. Our results suggest the overexpression of a full-autocrine loop of PRL and PRLr in monocytes that enhances the inflammatory response and apoptosis after priming with M. bovis antigens.

  10. Autophosphorylation of [alpha]CaMKII is Differentially Involved in New Learning and Unlearning Mechanisms of Memory Extinction

    Science.gov (United States)

    Kimura, Ryoichi; Silva, Alcino J.; Ohno, Masuo

    2008-01-01

    Accumulating evidence indicates the key role of [alpha]-calcium/calmodulin-dependent protein kinase II ([alpha]CaMKII) in synaptic plasticity and learning, but it remains unclear how this kinase participates in the processing of memory extinction. Here, we investigated the mechanism by which [alpha]CaMKII may mediate extinction by using…

  11. The effect of tyrphostins AG494 and AG1478 on the autocrine growth regulation of A549 and DU145 cells

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    Agnieszka Bojko

    2012-07-01

    Full Text Available We employed two selective EGFR tyrosine kinase inhibitors: AG494 (reversible and AG1478 (irreversible for growth regulation of human lung (A549 and prostate (DU145 cancer cell lines, cultured in chemically defined DMEM/F12 medium. Both tested tyrphostins significantly inhibited autocrine growth of the investigated cell lines. The action of AG494 was dose dependent, and at highest concentrations led to complete inhibition of growth. AG1478 seemed to be more effective at lower concentrations, but was unable to completely inhibit growth of A549 cells. Inhibition of EGFR kinase activity by AG494 in contrast to AG1478 had no effect on the activity of ERK in both cell lines. Both EGFR’s inhibitors induced apoptosis of the investigated lung and prostate cancer cell lines, but the proapoptotic effect of the investigated tyrphostins was greater in A549 than in DU145 cells. The tyrphostins arrested cell growth of DU145 and A549 cells in the G1 phase, similarly to other known inhibitors of EGFR. The influence of AG494 and AG1478 on the activity of two signaling proteins (AKT and ERK was dependent upon the kind of investigated cells. In the case of DU145 cells, there was an evident decline in enzymatic activity of both kinases (stronger for AG1478, while in A549, only AG1478 effectively inhibited the phosphorylation of Akt. Tyrphostins AG494 and AG1478 are ATP-competitors and are supposed to have a similar mechanism of action, but our results suggest that this is not quite true.

  12. Imidazoline receptors in the heart: a novel target and a novel mechanism of action that involves atrial natriuretic peptides

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    S. Mukaddam-Daher

    2004-08-01

    Full Text Available Chronic stimulation of sympathetic nervous activity contributes to the development and maintenance of hypertension, leading to left ventricular hypertrophy (LVH, arrhythmias and cardiac death. Moxonidine, an imidazoline antihypertensive compound that preferentially activates imidazoline receptors in brainstem rostroventrolateral medulla, suppresses sympathetic activation and reverses LVH. We have identified imidazoline receptors in the heart atria and ventricles, and shown that atrial I1-receptors are up-regulated in spontaneously hypertensive rats (SHR, and ventricular I1-receptors are up-regulated in hamster and human heart failure. Furthermore, cardiac I1-receptor binding decreased after chronic in vivo exposure to moxonidine. These studies implied that cardiac I1-receptors are involved in cardiovascular regulation. The presence of I1-receptors in the heart, the primary site of production of natriuretic peptides, atrial natriuretic peptide (ANP and brain natriuretic peptide (BNP, cardiac hormones implicated in blood pressure control and cardioprotection, led us to propose that ANP may be involved in the actions of moxonidine. In fact, acute iv administration of moxonidine (50 to 150 µg/rat dose-dependently decreased blood pressure, stimulated diuresis and natriuresis and increased plasma ANP and its second messenger, cGMP. Chronic SHR treatment with moxonidine (0, 60 and 120 µg kg-1 h-1, sc for 4 weeks dose-dependently decreased blood pressure, resulted in reversal of LVH and decreased ventricular interleukin 1ß concentration after 4 weeks of treatment. These effects were associated with a further increase in already elevated ANP and BNP synthesis and release (after 1 week, and normalization by 4 weeks. In conclusion, cardiac imidazoline receptors and natriuretic peptides may be involved in the acute and chronic effects of moxonidine.

  13. Mechanism-based Inactivation by Aromatization of the Transaminase BioA Involved in Biotin Biosynthesis in Mycobaterium tuberculosis

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Ce; Geders, Todd W.; Park, Sae Woong; Wilson, Daniel J.; Boshoff, Helena I.; Abayomi, Orishadipe; Barry, III, Clifton E.; Schnappinger, Dirk; Finzel, Barry C.; Aldrich, Courtney C. (Weill-Med); (UMM); (NIAID)

    2011-11-16

    BioA catalyzes the second step of biotin biosynthesis, and this enzyme represents a potential target to develop new antitubercular agents. Herein we report the design, synthesis, and biochemical characterization of a mechanism-based inhibitor (1) featuring a 3,6-dihydropyrid-2-one heterocycle that covalently modifies the pyridoxal 5'-phosphate (PLP) cofactor of BioA through aromatization. The structure of the PLP adduct was confirmed by MS/MS and X-ray crystallography at 1.94 {angstrom} resolution. Inactivation of BioA by 1 was time- and concentration-dependent and protected by substrate. We used a conditional knock-down mutant of M. tuberculosis to demonstrate the antitubercular activity of 1 correlated with BioA expression, and these results provide support for the designed mechanism of action.

  14. Docking Studies in Target Proteins Involved in Antibacterial Action Mechanisms: Extending the Knowledge on Standard Antibiotics to Antimicrobial Mushroom Compounds

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    Maria José Alves

    2014-01-01

    Full Text Available In the present work, the knowledge on target proteins of standard antibiotics was extended to antimicrobial mushroom compounds. Docking studies were performed for 34 compounds in order to evaluate their affinity to bacterial proteins that are known targets for some antibiotics with different mechanism of action: inhibitors of cell wall synthesis, inhibitors of protein synthesis, inhibitors of nucleic acids synthesis and antimetabolites. After validation of the molecular docking approach, virtual screening of all the compounds was performed against penicillin binding protein 1a (PBP1a, alanine racemase (Alr, d-alanyl-d-alanine synthetase (Ddl, isoleucyl-tRNA sinthetase (IARS, DNA gyrase subunit B, topoisomerase IV (TopoIV, dihydropteroate synthetase (DHPS and dihydrofolate reductase (DHFR using AutoDock4. Overall, it seems that for the selected mushroom compounds (namely, enokipodins, ganomycins and austrocortiluteins the main mechanism of the action is the inhibition of cell wall synthesis, being Alr and Ddl probable protein targets.

  15. Enhancement of pulmonary tumour seeding by human coagulation factors II, IX, X--an investigation into the possible mechanisms involved.

    OpenAIRE

    Purushotham, A D; McCulloch, P.; George, W. D.

    1991-01-01

    Warfarin inhibits metastasis in the animal model and injection of the Warfarin-dependent coagulation factor complex II, IX, X enhances pulmonary metastasis in the same model. We have studied two possible mechanisms responsible for the observed effect. Mtln3, rat mammary carcinoma cells, radiolabelled with 5-(125) Iodo-2'-deoxyuridine (IUDR) were injected intravenously in female Fisher 344 rats either alone or in combination with factor complex II, IX, X or bovine serum albumin. Following sacr...

  16. Insights into the dual activation mechanism involving bifunctional cinchona alkaloid thiourea organocatalysts: an NMR and DFT study.

    Science.gov (United States)

    Zhu, Jun-Ling; Zhang, Yong; Liu, Chong; Zheng, An-Min; Wang, Wei

    2012-11-02

    In-depth understanding of the activation mechanism in asymmetric organocatalysis is of great importance for rational development of highly efficient catalytic systems. In this Article, the mechanism for the direct vinylogous Michael reaction of α,β-unsaturated γ-butyrolactam (Nu) and chalcone (EI) catalyzed by the bifunctional cinchona alkaloid thiourea organocatalyst (Cat) was studied with a combination of experimental (NMR) and theoretical (DFT) approaches, through which a new dual activation pathway was found. The key feature of this new dual activation mechanism (Pathway C) is that one N-H(A) of the thiourea moiety and the N-H of the protonated amine in Cat simultaneously activate Nu, while the other N-H(B) of the thiourea moiety activates EI. Both the NMR measurement and the DFT calculation identified that the interaction of Cat with Nu is stronger than that with EI in the catalyst-substrate complexes. Kinetic studies via variable-temperature NMR measurements indicated that, with the experimental activation energy E(a) of 10.2 kcal/mol, the reaction is all first-order in Nu, EI, and Cat. The DFT calculation further revealed that the C-C bond formation is both the rate-determining and the stereoselectivity-controlling steps. In agreement with the experimental data, the energy barrier for the rate-determining step along Pathway C was calculated as 8.8 kcal/mol. The validity of Pathway C was further evidenced by the calculated enantioselectivity (100% ee) and diastereoselectivity (60:1 dr), which are in excellent match with the experimental data (98% ee and >30:1 dr, respectively). Mechanistic study on the Michael addition of nitromethane to chalcone catalyzed by the Catalyst I further identified the generality of this new dual activation mechanism in cinchona alkaloid thiourea organocatalysis.

  17. Insights into the epigenetic mechanisms involving histone lysine methylation and demethylation in ischemia induced damage and repair has therapeutic implication.

    Science.gov (United States)

    Chakravarty, Sumana; Jhelum, Priya; Bhat, Unis Ahmad; Rajan, Wenson D; Maitra, Swati; Pathak, Salil S; Patel, Anant B; Kumar, Arvind

    2017-01-01

    Cerebral ischemic stroke is one of the leading causes of death and disability worldwide. Therapeutic interventions to minimize ischemia-induced neural damage are limited due to poor understanding of molecular mechanisms mediating complex pathophysiology in stroke. Recently, epigenetic mechanisms mostly histone lysine (K) acetylation and deacetylation have been implicated in ischemic brain damage and have expanded the dimensions of potential therapeutic intervention to the systemic/local administration of histone deacetylase inhibitors. However, the role of other epigenetic mechanisms such as histone lysine methylation and demethylation in stroke-induced damage and subsequent recovery process is elusive. Here, we established an Internal Carotid Artery Occlusion (ICAO) model in CD1 mouse that resulted in mild to moderate level of ischemic damage to the striatum, as suggested by magnetic resonance imaging (MRI), TUNEL and histopathological staining along with an evaluation of neurological deficit score (NDS), grip strength and rotarod performance. The molecular investigations show dysregulation of a number of histone lysine methylases (KMTs) and few of histone lysine demethylases (KDMs) post-ICAO with significant global attenuation in the transcriptionally repressive epigenetic mark H3K9me2 in the striatum. Administration of Dimethyloxalylglycine (DMOG), an inhibitor of KDM4 or JMJD2 class of histone lysine demethylases, significantly ameliorated stroke-induced NDS by restoring perturbed H3K9me2 levels in the ischemia-affected striatum. Overall, these results highlight the novel role of epigenetic regulatory mechanisms controlling the epigenetic mark H3K9me2 in mediating the stroke-induced striatal damage and subsequent repair following mild to moderate cerebral ischemia.

  18. Mechanism of HCV's resistance to IFN-α in cell culture involves expression of functional IFN-α receptor 1

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    Lamaze Christophe

    2011-07-01

    Full Text Available Abstract The mechanisms underlying the Hepatitis C virus (HCV resistance to interferon alpha (IFN-α are not fully understood. We used IFN-α resistant HCV replicon cell lines and an infectious HCV cell culture system to elucidate the mechanisms of IFN-α resistance in cell culture. The IFN-α resistance mechanism of the replicon cells were addressed by a complementation study that utilized the full-length plasmid clones of IFN-α receptor 1 (IFNAR1, IFN-α receptor 2 (IFNAR2, Jak1, Tyk2, Stat1, Stat2 and the ISRE- luciferase reporter plasmid. We demonstrated that the expression of the full-length IFNAR1 clone alone restored the defective Jak-Stat signaling as well as Stat1, Stat2 and Stat3 phosphorylation, nuclear translocation and antiviral response against HCV in all IFN-α resistant cell lines (R-15, R-17 and R-24 used in this study. Moreover RT-PCR, Southern blotting and DNA sequence analysis revealed that the cells from both R-15 and R-24 series of IFN-α resistant cells have 58 amino acid deletions in the extracellular sub domain 1 (SD1 of IFNAR1. In addition, cells from the R-17 series have 50 amino acids deletion in the sub domain 4 (SD4 of IFNAR1 protein leading to impaired activation of Tyk2 kinase. Using an infectious HCV cell culture model we show here that viral replication in the infected Huh-7 cells is relatively resistant to exogenous IFN-α. HCV infection itself induces defective Jak-Stat signaling and impairs Stat1 and Stat2 phosphorylation by down regulation of the cell surface expression of IFNAR1 through the endoplasmic reticulum (ER stress mechanisms. The results of this study suggest that expression of cell surface IFNAR1 is critical for the response of HCV to exogenous IFN-α.

  19. Pharmacological Characterization of the Mechanisms Involved in Delayed Calcium Deregulation in SH-SY5Y Cells Challenged with Methadone

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    Sergio Perez-Alvarez

    2012-01-01

    Full Text Available Previously, we have shown that SH-SY5Y cells exposed to high concentrations of methadone died due to a necrotic-like cell death mechanism related to delayed calcium deregulation (DCD. In this study, we show that, in terms of their Ca2+ responses to 0.5 mM methadone, SH-SY5Y cells can be pooled into four different groups. In a broad pharmacological survey, the relevance of different Ca2+-related mechanisms on methadone-induced DCD was investigated including extracellular calcium, L-type Ca2+ channels, μ-opioid receptor, mitochondrial inner membrane potential, mitochondrial ATP synthesis, mitochondrial Ca2+/2Na+-exchanger, reactive oxygen species, and mitochondrial permeability transition. Only those compounds targeting mitochondria such as oligomycin, FCCP, CGP 37157, and cyclosporine A were able to amend methadone-induced Ca2+ dyshomeostasis suggesting that methadone induces DCD by modulating the ability of mitochondria to handle Ca2+. Consistently, mitochondria became dramatically shorter and rounder in the presence of methadone. Furthermore, analysis of oxygen uptake by isolated rat liver mitochondria suggested that methadone affected mitochondrial Ca2+ uptake in a respiratory substrate-dependent way. We conclude that methadone causes failure of intracellular Ca2+ homeostasis, and this effect is associated with morphological and functional changes of mitochondria. Likely, this mechanism contributes to degenerative side effects associated with methadone treatment.

  20. Involvement of two different mechanisms in trigeminal ganglion-evoked vasodilatation in the cat lower lip: role of experimental conditions.

    Science.gov (United States)

    Date, H; Kato, M; Izumi, H

    2000-03-15

    The present study was designed to examine the vasodilator mechanisms elicited by electrical stimulation of trigeminal ganglion (TG) in cat lower lip of the cats. When vago-sympathectomized cats were fixed into a stereotaxic frame by means of ear-bars, etc., the lip blood flow (LBF) increase evoked by lingual nerve (LN) stimulation (parasympathetic reflex response) was almost abolished in 15 out of 34 animals, but unaffected in the other 19. With the animal in the stereotaxic frame, electrical stimulation at sites within the TG evoked an LBF increase whether or not the LN stimulation-induced reflex response was intact. However, hexamethonium abolished the TG stimulation-induced LBF increase in animals whose brainstem parasympathetic reflex was intact, but reduced it by only 50% in animals whose reflex was impaired. This difference was seen in all experiments in which the electrode site was within the TG proper, regardless of its exact position. Although the underlying mechanism is unclear, these data suggest that when the TG is stimulated the LBF increase is entirely mediated via the parasympathetic reflex mechanism in animals whose brainstem reflex is intact, and that an antidromic vasodilatation occurs only in animals whose brainstem parasympathetic reflex is impaired.

  1. Physiological Mechanisms Only Tell Half Story: Multiple Biological Processes are involved in Regulating Freezing Tolerance of Imbibed Lactuca sativa Seeds.

    Science.gov (United States)

    Jaganathan, Ganesh K; Han, Yingying; Li, Weijie; Song, Danping; Song, Xiaoyan; Shen, Mengqi; Zhou, Qiang; Zhang, Chenxue; Liu, Baolin

    2017-03-13

    The physiological mechanisms by which imbibed seeds survive freezing temperatures in their natural environment have been categorized as freezing avoidance by supercooling and freezing tolerance by extracellular freeze-desiccation, but the biochemical and molecular mechanisms conferring seed freezing tolerance is unexplored. In this study, using imbibed Lactuca sativa seeds we show that fast cooled seeds (60 °C h(-1)) suffered significantly higher membrane damage at temperature between -20 °C and -10 °C than slow cooled (3 °Ch(-1)) seeds (P  0.05). However, both SOD activity and accumulation of free proline were induced significantly after slow cooling to -20 °C compared with fast cooling. RNA-seq demonstrated that multiple pathways were differentially regulated between slow and fast cooling. Real-time verification of some differentially expressed genes (DEGs) revealed that fast cooling caused mRNA level changes of plant hormone and ubiquitionation pathways at higher sub-zero temperature, whilst slow cooling caused mRNA level change of those pathways at lower sub-zero ttemperatures. Thus, we conclude that imbibed seed tolerate low temperature not only by physiological mechanisms but also by biochemical and molecular changes.

  2. An FGF autocrine loop initiated in second heart field mesoderm regulates morphogenesis at the arterial pole of the heart

    Science.gov (United States)

    Park, Eon Joo; Watanabe, Yusuke; Smyth, Graham; Miyagawa-Tomita, Sachiko; Meyers, Erik; Klingensmith, John; Camenisch, Todd; Buckingham, Margaret; Moon, Anne M.

    2009-01-01

    In order to understand how secreted signals regulate complex morphogenetic events, it is crucial to identify their cellular targets. By conditional inactivation of Fgfr1 and Fgfr2 and overexpression of the FGF antagonist sprouty 2 in different cell types, we have dissected the role of FGF signaling during heart outflow tract development in mouse. Contrary to expectation, cardiac neural crest and endothelial cells are not primary paracrine targets. FGF signaling within second heart field mesoderm is required for remodeling of the outflow tract: when disrupted, outflow myocardium fails to produce extracellular matrix and TGFβ and BMP signals essential for endothelial cell transformation and invasion of cardiac neural crest. We conclude that an autocrine regulatory loop, initiated by the reception of FGF signals by the mesoderm, regulates correct morphogenesis at the arterial pole of the heart. These findings provide new insight into how FGF signaling regulates context-dependent cellular responses during development. PMID:18832392

  3. Timely activation of budding yeast APCCdh1 involves degradation of its inhibitor, Acm1, by an unconventional proteolytic mechanism.

    Directory of Open Access Journals (Sweden)

    Michael Melesse

    Full Text Available Regulated proteolysis mediated by the ubiquitin proteasome system is a fundamental and essential feature of the eukaryotic cell division cycle. Most proteins with cell cycle-regulated stability are targeted for degradation by one of two related ubiquitin ligases, the Skp1-cullin-F box protein (SCF complex or the anaphase-promoting complex (APC. Here we describe an unconventional cell cycle-regulated proteolytic mechanism that acts on the Acm1 protein, an inhibitor of the APC activator Cdh1 in budding yeast. Although Acm1 can be recognized as a substrate by the Cdc20-activated APC (APCCdc20 in anaphase, APCCdc20 is neither necessary nor sufficient for complete Acm1 degradation at the end of mitosis. An APC-independent, but 26S proteasome-dependent, mechanism is sufficient for complete Acm1 clearance from late mitotic and G1 cells. Surprisingly, this mechanism appears distinct from the canonical ubiquitin targeting pathway, exhibiting several features of ubiquitin-independent proteasomal degradation. For example, Acm1 degradation in G1 requires neither lysine residues in Acm1 nor assembly of polyubiquitin chains. Acm1 was stabilized though by conditional inactivation of the ubiquitin activating enzyme Uba1, implying some requirement for the ubiquitin pathway, either direct or indirect. We identified an amino terminal predicted disordered region in Acm1 that contributes to its proteolysis in G1. Although ubiquitin-independent proteasome substrates have been described, Acm1 appears unique in that its sensitivity to this mechanism is strictly cell cycle-regulated via cyclin-dependent kinase (Cdk phosphorylation. As a result, Acm1 expression is limited to the cell cycle window in which Cdk is active. We provide evidence that failure to eliminate Acm1 impairs activation of APCCdh1 at mitotic exit, justifying its strict regulation by cell cycle-dependent transcription and proteolytic mechanisms. Importantly, our results reveal that strict cell

  4. Structures and molecular mechanisms for common 15q13.3 microduplications involving CHRNA7: benign or pathological?

    Science.gov (United States)

    Szafranski, Przemyslaw; Schaaf, Christian P; Person, Richard E; Gibson, Ian B; Xia, Zhilian; Mahadevan, Sangeetha; Wiszniewska, Joanna; Bacino, Carlos A; Lalani, Seema; Potocki, Lorraine; Kang, Sung-Hae; Patel, Ankita; Cheung, Sau Wai; Probst, Frank J; Graham, Brett H; Shinawi, Marwan; Beaudet, Arthur L; Stankiewicz, Pawel

    2010-07-01

    We have investigated four approximately 1.6-Mb microduplications and 55 smaller 350-680-kb microduplications at 15q13.2-q13.3 involving the CHRNA7 gene that were detected by clinical microarray analysis. Applying high-resolution array-CGH, we mapped all 118 chromosomal breakpoints of these microduplications. We also sequenced 26 small microduplication breakpoints that were clustering at hotspots of nonallelic homologous recombination (NAHR). All four large microduplications likely arose by NAHR between BP4 and BP5 LCRs, and 54 small microduplications arose by NAHR between two CHRNA7-LCR copies. We identified two classes of approximately 1.6-Mb microduplications and five classes of small microduplications differing in duplication size, and show that they duplicate the entire CHRNA7. We propose that size differences among small microduplications result from preexisting heterogeneity of the common BP4-BP5 inversion. Clinical data and family histories of 11 patients with small microduplications involving CHRNA7 suggest that these microduplications might be associated with developmental delay/mental retardation, muscular hypotonia, and a variety of neuropsychiatric disorders. However, we conclude that these microduplications and their associated potential for increased dosage of the CHRNA7-encoded alpha 7 subunit of nicotinic acetylcholine receptors are of uncertain clinical significance at present. Nevertheless, if they prove to have a pathological effects, their high frequency could make them a common risk factor for many neurobehavioral disorders.

  5. Determination of rate constants for the uptake process involving SO{sub 2} and an aerosol particle. A quantum mechanics/molecular mechanics and quantum statistical investigation

    Energy Technology Data Exchange (ETDEWEB)

    Madsen, Marianne Sloth [Department of Chemistry, H.C. Orsted Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen O (Denmark); Danish Meteorological Institute, Lyngbyvej 100, DK-2100 Copenhagen O (Denmark)], E-mail: msm@dmi.dk; Gross, Allan [Department of Chemistry, H.C. Orsted Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen O (Denmark); Danish Meteorological Institute, Lyngbyvej 100, DK-2100 Copenhagen O (Denmark); Falsig, Hanne [Department of Chemistry, H.C. Orsted Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen O (Denmark); Kongsted, Jacob [Department of Theoretical Chemistry, Chemical Center, University of Lund, P.O. Box 124, S-22100 Lund (Sweden); Osted, Anders; Mikkelsen, Kurt V. [Department of Chemistry, H.C. Orsted Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen O (Denmark); Christiansen, Ove [Department of Chemistry, University of Aarhus, Langelandsgade 140, DK-8000 Aarhus C (Denmark)

    2008-06-02

    We present a combined quantum mechanics/molecular mechanics and quantum statistical investigation of the interactions between a molecule (SO{sub 2}) and an aerosol particle including rate constants for the uptake process. A coupled cluster/molecular mechanics method including explicit polarization is used along with a quantum statistical method for calculating sticking coefficients. The importance of the polarization of the classical subsystem (the aerosol particle), the size of the classical subsystem and the size of one-electron basis sets are studied. The interaction energy is divided into van der Waals, electrostatic and polarization contributions. Relevant binding sites for the evaluation of the sticking coefficient are identified. These are classified into three groups according to the strength of the molecule-aerosol particle interaction energy. The identification of binding sites provides relevant information used in the quantum statistical method and thereby knowledge of the magnitude of the sticking coefficients for the different binding sites along with the total rates for the uptake processes between the aerosol particle and the SO{sub 2} molecule.

  6. Characterization of the autocrine/paracrine function of vitamin D in human gingival fibroblasts and periodontal ligament cells.

    Directory of Open Access Journals (Sweden)

    Kaining Liu

    Full Text Available BACKGROUND: We previously demonstrated that 25-hydroxyvitamin D(3, the precursor of 1α,25-dihydroxyvitamin D(3, is abundant around periodontal soft tissues. Here we investigate whether 25-hydroxyvitamin D(3 is converted to 1α,25-dihydroxyvitamin D(3 in periodontal soft tissue cells and explore the possibility of an autocrine/paracrine function of 1α,25-dihydroxyvitamin D(3 in periodontal soft tissue cells. METHODOLOGY/PRINCIPAL FINDINGS: We established primary cultures of human gingival fibroblasts and human periodontal ligament cells from 5 individual donors. We demonstrated that 1α-hydroxylase was expressed in human gingival fibroblasts and periodontal ligament cells, as was cubilin. After incubation with the 1α-hydroxylase substrate 25-hydroxyvitamin D(3, human gingival fibroblasts and periodontal ligament cells generated detectable 1α,25-dihydroxyvitamin D(3 that resulted in an up-regulation of CYP24A1 and RANKL mRNA. A specific knockdown of 1α-hydroxylase in human gingival fibroblasts and periodontal ligament cells using siRNA resulted in a significant reduction in both 1α,25-dihydroxyvitamin D(3 production and mRNA expression of CYP24A1 and RANKL. The classical renal regulators of 1α-hydroxylase (parathyroid hormone, calcium and 1α,25-dihydroxyvitamin D(3 and Porphyromonas gingivalis lipopolysaccharide did not influence 1α-hydroxylase expression significantly, however, interleukin-1β and sodium butyrate strongly induced 1α-hydroxylase expression in human gingival fibroblasts and periodontal ligament cells. CONCLUSIONS/SIGNIFICANCE: In this study, the expression, activity and functionality of 1α-hydroxylase were detected in human gingival fibroblasts and periodontal ligament cells, raising the possibility that vitamin D acts in an autocrine/paracrine manner in these cells.

  7. Autocrine Signaling Underlies Fast Repetitive Plasma Membrane Translocation of Conventional and Novel Protein Kinase C Isoforms in β Cells.

    Science.gov (United States)

    Wuttke, Anne; Yu, Qian; Tengholm, Anders

    2016-07-15

    PKC signaling has been implicated in the regulation of many cell functions, including metabolism, cell death, proliferation, and secretion. Activation of conventional and novel PKC isoforms is associated with their Ca(2+)- and/or diacylglycerol (DAG)-dependent translocation to the plasma membrane. In β cells, exocytosis of insulin granules evokes brief (<10 s) local DAG elevations ("spiking") at the plasma membrane because of autocrine activation of P2Y1 purinoceptors by ATP co-released with insulin. Using total internal reflection microscopy, fluorescent protein-tagged PKCs, and signaling biosensors, we investigated whether DAG spiking causes membrane recruitment of PKCs and whether different classes of PKCs show characteristic responses. Glucose stimulation of MIN6 cells triggered DAG spiking with concomitant repetitive translocation of the novel isoforms PKCδ, PKCϵ, and PKCη. The conventional PKCα, PKCβI, and PKCβII isoforms showed a more complex pattern with both rapid and slow translocation. K(+) depolarization-induced PKCϵ translocation entirely mirrored DAG spiking, whereas PKCβI translocation showed a sustained component, reflecting the subplasma membrane Ca(2+) concentration ([Ca(2+)]pm), with additional effect during DAG spikes. Interference with DAG spiking by purinoceptor inhibition prevented intermittent translocation of PKCs and reduced insulin secretion but did not affect [Ca(2+)]pm elevation or sustained PKCβI translocation. The muscarinic agonist carbachol induced pronounced transient PKCβI translocation and sustained recruitment of PKCϵ. When rise of [Ca(2+)]pm was prevented, the carbachol-induced DAG and PKCϵ responses were somewhat reduced, but PKCβI translocation was completely abolished. We conclude that exocytosis-induced DAG spikes efficiently recruit both conventional and novel PKCs to the β cell plasma membrane. PKC signaling is thus implicated in autocrine regulation of β cell function.

  8. Autocrine Signaling Underlies Fast Repetitive Plasma Membrane Translocation of Conventional and Novel Protein Kinase C Isoforms in β Cells*

    Science.gov (United States)

    Wuttke, Anne; Yu, Qian; Tengholm, Anders

    2016-01-01

    PKC signaling has been implicated in the regulation of many cell functions, including metabolism, cell death, proliferation, and secretion. Activation of conventional and novel PKC isoforms is associated with their Ca2+- and/or diacylglycerol (DAG)-dependent translocation to the plasma membrane. In β cells, exocytosis of insulin granules evokes brief (<10 s) local DAG elevations (“spiking”) at the plasma membrane because of autocrine activation of P2Y1 purinoceptors by ATP co-released with insulin. Using total internal reflection microscopy, fluorescent protein-tagged PKCs, and signaling biosensors, we investigated whether DAG spiking causes membrane recruitment of PKCs and whether different classes of PKCs show characteristic responses. Glucose stimulation of MIN6 cells triggered DAG spiking with concomitant repetitive translocation of the novel isoforms PKCδ, PKCϵ, and PKCη. The conventional PKCα, PKCβI, and PKCβII isoforms showed a more complex pattern with both rapid and slow translocation. K+ depolarization-induced PKCϵ translocation entirely mirrored DAG spiking, whereas PKCβI translocation showed a sustained component, reflecting the subplasma membrane Ca2+ concentration ([Ca2+]pm), with additional effect during DAG spikes. Interference with DAG spiking by purinoceptor inhibition prevented intermittent translocation of PKCs and reduced insulin secretion but did not affect [Ca2+]pm elevation or sustained PKCβI translocation. The muscarinic agonist carbachol induced pronounced transient PKCβI translocation and sustained recruitment of PKCϵ. When rise of [Ca2+]pm was prevented, the carbachol-induced DAG and PKCϵ responses were somewhat reduced, but PKCβI translocation was completely abolished. We conclude that exocytosis-induced DAG spikes efficiently recruit both conventional and novel PKCs to the β cell plasma membrane. PKC signaling is thus implicated in autocrine regulation of β cell function. PMID:27226533

  9. Autocrine role of estrogens in the augmentation of luteinizing hormone receptor formation in cultured rat granulosa cells.

    Science.gov (United States)

    Kessel, B; Liu, Y X; Jia, X C; Hsueh, A J

    1985-06-01

    The effects of estrogens on gonadotropin-stimulated luteinizing hormone (LH) receptor formation were examined in primary cultures of rat granulosa cells. Granulosa cells were cultured for 3 days with increasing concentrations of follicle-stimulating hormone (FSH) in the presence or absence of native and synthetic estrogens. Follicle-stimulating hormone stimulated LH receptor formation in a dose-dependent fashion, and estrogens enhanced the FSH-stimulated LH receptor content by decreasing the apparent ED50 of FSH. At 6.25 ng/ml FSH, the enhancement in LH receptor was estrogen dose dependent, with an ED50 value of about 3 X 10(-9) M for 17 beta-estradiol. The increased LH receptor content seen in cells treated with FSH and estrogen was correlated with increased cAMP production by these cells in response to LH stimulation. Time course studies revealed enhancement of FSH-stimulated LH receptor induction at 48 and 72 h of culture. Granulosa cells were also cultured with FSH for 2 days to induce functional LH receptors, then further cultured for 3 days with LH in the presence or absence of estrogens. At 30 ng/ml LH, increasing concentrations of estrogens maintained LH receptor content in a dose-dependent fashion, with their relative estrogenic potencies in keeping with reported binding affinities to estrogen receptors. An autocrine role of estrogens on LH receptor formation was further tested in granulosa cells treated with FSH and an aromatase substrate (androstenedione) to increase estrogen biosynthesis. Cotreatment with semipurified estrogen antibodies partially blocked the FSH stimulation of LH receptors, whereas nonimmune serum was ineffective. Also, inclusion of diethylstilbestrol prevented the inhibitory effect of the estrogen antibodies. Thus, local estrogens in ovarian follicles may play an autocrine role in granulosa cells to enhance LH receptor formation and to increase granulosa cell responsiveness to the LH surge, with subsequent ovulation and adequate

  10. Transcriptome profiling of Pinus radiata juvenile wood with contrasting stiffness identifies putative candidate genes involved in microfibril orientation and cell wall mechanics

    Directory of Open Access Journals (Sweden)

    Wu Harry X

    2011-10-01

    Full Text Available Abstract Background The mechanical properties of wood are largely determined by the orientation of cellulose microfibrils in secondary cell walls. Several genes and their allelic variants have previously been found to affect microfibril angle (MFA and wood stiffness; however, the molecular mechanisms controlling microfibril orientation and mechanical strength are largely uncharacterised. In the present study, cDNA microarrays were used to compare gene expression in developing xylem with contrasting stiffness and MFA in juvenile Pinus radiata trees in order to gain further insights into the molecular mechanisms underlying microfibril orientation and cell wall mechanics. Results Juvenile radiata pine trees with higher stiffness (HS had lower MFA in the earlywood and latewood of each ring compared to low stiffness (LS trees. Approximately 3.4 to 14.5% out of 3, 320 xylem unigenes on cDNA microarrays were differentially regulated in juvenile wood with contrasting stiffness and MFA. Greater variation in MFA and stiffness was observed in earlywood compared to latewood, suggesting earlywood contributes most to differences in stiffness; however, 3-4 times more genes were differentially regulated in latewood than in earlywood. A total of 108 xylem unigenes were differentially regulated in juvenile wood with HS and LS in at least two seasons, including 43 unigenes with unknown functions. Many genes involved in cytoskeleton development and secondary wall formation (cellulose and lignin biosynthesis were preferentially transcribed in wood with HS and low MFA. In contrast, several genes involved in cell division and primary wall synthesis were more abundantly transcribed in LS wood with high MFA. Conclusions Microarray expression profiles in Pinus radiata juvenile wood with contrasting stiffness has shed more light on the transcriptional control of microfibril orientation and the mechanical properties of wood. The identified candidate genes provide an

  11. Involvement of spinal glutamate transporter-1 in the development of mechanical allodynia and hyperalgesia associated with type 2 diabetes

    Directory of Open Access Journals (Sweden)

    Shi J

    2016-11-01

    Full Text Available Jinshan Shi,1,* Ke Jiang,2,* Zhaoduan Li,3 1Department of Anesthesiology, Guizhou Provincial People’s Hospital, 2Department of Anesthesiology, The Affiliated Hospital of Guizhou Medical University, Guiyang, 3Department of Anesthesiology, Tianjin Nankai Hospital, Tianjin, People’s Republic of China *These authors contributed equally to this work Abstract: Little is known about the effects of the development of type 2 diabetes on glutamate homeostasis in the spinal cord. Therefore, we quantified the extracellular levels of glutamate in the spinal cord of Zucker diabetic fatty (ZDF rats using in vivo microdialysis. In addition, protein levels of glutamate transporter-1 (GLT-1 in the spinal cord of ZDF rats were measured using Western blot. Finally, the effects of repeated intrathecal injections of ceftriaxone, which was previously shown to enhance GLT-1 expression, on the development of mechanical allodynia and hyperalgesia as well as on basal extracellular level of glutamate and the expression of GLT-1 in the spinal cord of ZDF rats were evaluated. It was found that ZDF rats developed mechanical hyperalgesia and allodynia, which were associated with increased basal extracellular levels of glutamate and attenuated levels of GLT-1 expression in the spinal cord, particularly in the dorsal horn. Furthermore, repeated intrathecal administrations of ceftriaxone dose-dependently prevented the development of mechanical hyperalgesia and allodynia in ZDF rats, which were correlated with enhanced GLT-1 expression without altering the basal glutamate levels in the spinal cord of ZDF rats. Overall, the results suggested that impaired glutamate reuptake in the spinal cord may contribute to the development of neuropathic pains in type 2 diabetes. Keywords: diabetes, peripheral neuropathy, spinal cord, Zucker diabetic fatty rats, glutamate, glutamate transporter-1

  12. Rapid and Localized Mechanical Stimulation and Adhesion Assay: TRPM7 Involvement in Calcium Signaling and Cell Adhesion.

    Directory of Open Access Journals (Sweden)

    Wagner Shin Nishitani

    Full Text Available A cell mechanical stimulation equipment, based on cell substrate deformation, and a more sensitive method for measuring adhesion of cells were developed. A probe, precisely positioned close to the cell, was capable of a vertical localized mechanical stimulation with a temporal frequency of 207 Hz, and strain magnitude of 50%. This setup was characterized and used to probe the response of Human Umbilical Endothelial Vein Cells (HUVECs in terms of calcium signaling. The intracellular calcium ion concentration was measured by the genetically encoded Cameleon biosensor, with the Transient Receptor Potential cation channel, subfamily M, member 7 (TRPM7 expression inhibited. As TRPM7 expression also regulates adhesion, a relatively simple method for measuring adhesion of cells was also developed, tested and used to study the effect of adhesion alone. Three adhesion conditions of HUVECs on polyacrylamide gel dishes were compared. In the first condition, the substrate is fully treated with Sulfo-SANPAH crosslinking and fibronectin. The other two conditions had increasingly reduced adhesion: partially treated (only coated with fibronectin, with no use of Sulfo-SANPAH, at 5% of the normal amount and non-treated polyacrylamide gels. The cells showed adhesion and calcium response to the mechanical stimulation correlated to the degree of gel treatment: highest for fully treated gels and lowest for non-treated ones. TRPM7 inhibition by siRNA on HUVECs caused an increase in adhesion relative to control (no siRNA treatment and non-targeting siRNA, but a decrease to 80% of calcium response relative to non-targeting siRNA which confirms the important role of TRPM7 in mechanotransduction despite the increase in adhesion.

  13. Rapid and Localized Mechanical Stimulation and Adhesion Assay: TRPM7 Involvement in Calcium Signaling and Cell Adhesion.

    Science.gov (United States)

    Nishitani, Wagner Shin; Alencar, Adriano Mesquita; Wang, Yingxiao

    2015-01-01

    A cell mechanical stimulation equipment, based on cell substrate deformation, and a more sensitive method for measuring adhesion of cells were developed. A probe, precisely positioned close to the cell, was capable of a vertical localized mechanical stimulation with a temporal frequency of 207 Hz, and strain magnitude of 50%. This setup was characterized and used to probe the response of Human Umbilical Endothelial Vein Cells (HUVECs) in terms of calcium signaling. The intracellular calcium ion concentration was measured by the genetically encoded Cameleon biosensor, with the Transient Receptor Potential cation channel, subfamily M, member 7 (TRPM7) expression inhibited. As TRPM7 expression also regulates adhesion, a relatively simple method for measuring adhesion of cells was also developed, tested and used to study the effect of adhesion alone. Three adhesion conditions of HUVECs on polyacrylamide gel dishes were compared. In the first condition, the substrate is fully treated with Sulfo-SANPAH crosslinking and fibronectin. The other two conditions had increasingly reduced adhesion: partially treated (only coated with fibronectin, with no use of Sulfo-SANPAH, at 5% of the normal amount) and non-treated polyacrylamide gels. The cells showed adhesion and calcium response to the mechanical stimulation correlated to the degree of gel treatment: highest for fully treated gels and lowest for non-treated ones. TRPM7 inhibition by siRNA on HUVECs caused an increase in adhesion relative to control (no siRNA treatment) and non-targeting siRNA, but a decrease to 80% of calcium response relative to non-targeting siRNA which confirms the important role of TRPM7 in mechanotransduction despite the increase in adhesion.

  14. Apparent anti-Woodward-Hoffmann addition to a nickel bis(dithiolene) complex: the reaction mechanism involves reduced, dimetallic intermediates.

    Science.gov (United States)

    Dang, Li; Shibl, Mohamed F; Yang, Xinzheng; Harrison, Daniel J; Alak, Aiman; Lough, Alan J; Fekl, Ulrich; Brothers, Edward N; Hall, Michael B

    2013-04-01

    Nickel dithiolene complexes have been proposed as electrocatalysts for alkene purification. Recent studies of the ligand-based reactions of Ni(tfd)2 (tfd = S2C2(CF3)2) and its anion [Ni(tfd)2](-) with alkenes (ethylene and 1-hexene) showed that in the absence of the anion, the reaction proceeds most rapidly to form the intraligand adduct, which decomposes by releasing a substituted dihydrodithiin. However, the presence of the anion increases the rate of formation of the stable cis-interligand adduct, and decreases the rate of dihydrodithiin formation and decomposition. In spite of both computational and experimental studies, the mechanism, especially the role of the anion, remained somewhat elusive. We are now providing a combined experimental and computational study that addresses the mechanism and explains the role of the anion. A kinetic study (global analysis) for the reaction of 1-hexene is reported, which supports the following mechanism: (1) reversible intraligand addition, (2) oxidation of the intraligand addition product prior to decomposition, and (3) interligand adduct formation catalyzed by Ni(tfd)2(-). Density functional theory (DFT) calculations were performed on the Ni(tfd)2/Ni(tfd)2(-)/ethylene system to shed light on the selectivity of adduct formation in the absence of anion and on the mechanism in which Ni(tfd)2(-) shifts the reaction from intraligand addition to interligand addition. Computational results show that in the neutral system the free energy of activation for intraligand addition is lower than that for interligand addition, in agreement with the experimental results. The computations predict that the anion enhances the rate of the cis-interligand adduct formation by forming a dimetallic complex with the neutral complex. The [(Ni(tfd)2)2](-) dimetallic complex then coordinates ethylene and isomerizes to form a Ni,S-bound ethylene complex, which then rapidly isomerizes to the stable interligand adduct but not to the intraligand adduct

  15. The β-amyloid protein induces S100β expression in rat hippocampus through a mechanism that involves IL-1

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To explore the effect of β-amyloid protein (Aβ) on S100β expression in rat hippocampus and its mechanisms. Methods At 7 days after bilateral stereotaxis injection of different dose of fibrillar Aβ 25-35 and interluekin-1 receptor antagonist (IL-1ra) into the rat CA1 region, the learning and memory abilities of rats were tested with passive avoidance task. Amyloid deposition was detected by using Congo red staining technique. Nissl staining and immunohistochemical techniques were used to analyze th...

  16. Diazepam neuroprotection in excitotoxic and oxidative stress involves a mitochondrial mechanism additional to the GABAAR and hypothermic effects.

    Science.gov (United States)

    Sarnowska, Anna; Beresewicz, Małgorzata; Zabłocka, Barbara; Domańska-Janik, Krystyna

    2009-01-01

    The aim of the present investigation was to analyze the molecular mechanism(s) of diazepam neuroprotection in two models of selective neuronal death in CA1 sector of hippocampus: in vivo following transient gerbil brain ischemia and in vitro in rat hippocampal brain slices subjected to glutamatergic (100 microM NMDA) or oxidative (30 microM tertbutyl-hydroksyperoxide (TBH)) stress. In the in vivo model the diazepam treatment (two doses of 10mg/kg i.p. 30 and 90 min after the insult) resulted in more than 60% of CA1 hippocampal neurons surviving the insult comparing with 15% in untreated animals. To test whether the protective effect of diazepam was due to the postulated drug-induced hypothermia we followed the fluxes of body temperature during postischemic reperfusion: diazepam reduced temperature from 36.6+/-1 degrees C to 33.4+/-2 degrees C. Equivalent hypothermia induced and maintained in animals after ischemia did not prevent neuronal cell loss to the same extent as diazepam did (42.8+/-9.2% and 72.4+/-14.5% of live neurons, respectively). In vitro, under constant temperature conditions, diazepam exerted neuroprotective effects following a "U-shaped" dose-response curve, with concentration efficacy window of 0.5-10 microM. Five micro-molar diazepam showed significant protection by reducing over 50% the number of (dead) propidium iodide labeled cells even in the presence of GABA(A) receptor antagonist bicuculline. Next, we have shown that diazepam reduced the efflux of cytochrome c out of mitochondria both in compromised CA1 neurons in vitro and in isolated mitochondria treated with 30 microM THB. Our results suggest that the neuroprotective action of diazepam relies on additional mechanism(s) and not solely on its hypothermic effect. We suggest that diazepam evokes neuroprotection through its central receptors located on the GABA(A) receptor complex and, possibly, through its peripheral receptor, the translocator protein TSPO (previously called the peripheral

  17. Adenovirus Recruits Dynein by an Evolutionary Novel Mechanism Involving Direct Binding to pH-Primed Hexon

    Directory of Open Access Journals (Sweden)

    Julian Scherer

    2011-08-01

    Full Text Available Following receptor-mediated uptake into endocytic vesicles and escape from the endosome, adenovirus is transported by cytoplasmic dynein along microtubules to the perinuclear region of the cell. How motor proteins are recruited to viruses for their own use has begun to be investigated only recently. We review here the evidence for a role for dynein and other motor proteins in adenovirus infectivity. We also discuss the implications of recent studies on the mechanism of dynein recruitment to adenovirus for understanding the relationship between pathogenic and physiological cargo recruitment and for the evolutionary origins of dynein-mediated adenovirus transport.

  18. Exploring the Mechanisms of Pathogenesis in Prostate Cancer Involving TMPRSS2-ERG (Or ETV1) Gene Rearrangement

    Science.gov (United States)

    2009-01-01

    Esther Baena, PhD; Zhe Li, PhD. Conclusion: We planned to use both a series of mouse models and biochemical approaches to study the mechanisms of...Apr 1, 2006). 9. S. A. Tomlins et al., Science 310, 644 (Oct 28, 2005). 10. J. Wang , Y. Cai, C. Ren, M. Ittmann, Cancer Res 66, 8347 (Sep 1, 2006...Cancer Res 68, 3584 (May 15, 2008). 23. S. Wang et al., Cancer Cell 4, 209 (Sep, 2003). 24. Y. Y. Kisanuki et al., Dev Biol 230, 230 (Feb 15, 2001

  19. Huang Qi Jian Zhong Pellet Attenuates TNBS-Induced Colitis in Rats via Mechanisms Involving Improvement of Energy Metabolism

    OpenAIRE

    Duan-Yong Liu; Chun-Shui Pan; Yu-Ying Liu; Xiao-Hong Wei; Chang-Man Zhou; Kai Sun; Ke He; Chong Li; Li Yan; Jing-Yu Fan; Chuan-She Wang; Toshifumi Hibi; Hong-Ning Liu; Jing-Yan Han

    2013-01-01

    Huang Qi Jian Zhong Pellet (HQJZ) is a famous Chinese medicine formula for treatment of various gastrointestinal tract diseases. This study investigated the role of HQJZ in 2,4,6-trinitrobenzene sulfonic acid- (TNBS-) induced colitis and its underlying mechanism. Colonic mucosal injury was induced by TNBS in the Sprague-Dawley rats. In the HQJZ treatment group, HQJZ was administered (2 g/kg) for 14 days starting from day 1 after TNBS infusion. Colonic mucosal injury occurred obviously 1 day a...

  20. A novel COX-independent mechanism of sulindac sulfide involves cleavage of epithelial cell adhesion molecule protein.

    Science.gov (United States)

    Liggett, Jason L; Min, Kyung-Won; Smolensky, Dmitriy; Baek, Seung Joon

    2014-08-01

    Non-steroidal anti-inflammatory drugs (NSAIDs) are extensively used over the counter to treat headaches and inflammation as well as clinically to prevent cancer among high-risk groups. The inhibition of cyclooxygenase (COX) activity by NSAIDs plays a role in their anti-tumorigenic properties. NSAIDs also have COX-independent activity which is not fully understood. In this study, we report a novel COX-independent mechanism of sulindac sulfide (SS), which facilitates a previously uncharacterized cleavage of epithelial cell adhesion molecule (EpCAM) protein. EpCAM is a type I transmembrane glycoprotein that has been implemented as an over-expressed oncogene in many cancers including colon, breast, pancreas, and prostate. We found EpCAM to be down-regulated by SS in a manner that is independent of COX activity, transcription regulation, de novo protein synthesis, and proteasomal degradation pathway. Our findings clearly demonstrate that SS drives cleavage of the extracellular portion of EpCAM near the N-terminus. This SS driven cleavage is blocked by a deleting amino acids 55-81 as well as simply mutating arginine residues at positions 80 and 81 to alanine of EpCAM. Proteolysis of EpCAM by SS may provide a novel mechanism by which NSAIDs affect anti-tumorigenesis at the post-translational level.

  1. RNA-Binding Proteins in Trichomonas vaginalis: Atypical Multifunctional Proteins Involved in a Posttranscriptional Iron Regulatory Mechanism

    Science.gov (United States)

    Figueroa-Angulo, Elisa E.; Calla-Choque, Jaeson S.; Mancilla-Olea, Maria Inocente; Arroyo, Rossana

    2015-01-01

    Iron homeostasis is highly regulated in vertebrates through a regulatory system mediated by RNA-protein interactions between the iron regulatory proteins (IRPs) that interact with an iron responsive element (IRE) located in certain mRNAs, dubbed the IRE-IRP regulatory system. Trichomonas vaginalis, the causal agent of trichomoniasis, presents high iron dependency to regulate its growth, metabolism, and virulence properties. Although T. vaginalis lacks IRPs or proteins with aconitase activity, possesses gene expression mechanisms of iron regulation at the transcriptional and posttranscriptional levels. However, only one gene with iron regulation at the transcriptional level has been described. Recently, our research group described an iron posttranscriptional regulatory mechanism in the T. vaginalis tvcp4 and tvcp12 cysteine proteinase mRNAs. The tvcp4 and tvcp12 mRNAs have a stem-loop structure in the 5'-coding region or in the 3'-UTR, respectively that interacts with T. vaginalis multifunctional proteins HSP70, α-Actinin, and Actin under iron starvation condition, causing translation inhibition or mRNA stabilization similar to the previously characterized IRE-IRP system in eukaryotes. Herein, we summarize recent progress and shed some light on atypical RNA-binding proteins that may participate in the iron posttranscriptional regulation in T. vaginalis. PMID:26703754

  2. Compensatory mechanism involving the knee joint of the intact limb during gait in unilateral below-knee amputees.

    Science.gov (United States)

    Beyaert, C; Grumillier, C; Martinet, N; Paysant, J; André, J-M

    2008-08-01

    This study evaluated the asymmetry of knee kinetics during uncomfortable gait induced by prosthesis misalignment to further demonstrate the compensatory function of the knee joint of the intact limb during gait. Three-dimensional gait analysis including knee kinematics and kinetics at the beginning of stance phase was conducted in 15 healthy subjects and 17 unilateral trans-tibial amputees (TTA) walking at self-selected speed in three conditions of prosthetic alignment: initial alignment (IA); initial alignment altered either by 6 degrees of internal rotation (IR) or by 6 degrees of external rotation (ER) applied on the pylon. Patients reported best comfort of gait in IA condition and discomfort mainly in IR condition. Maximum knee flexion and knee total work at power phases K0-K2 were significantly higher in intact limbs compared to prosthetic and control limbs. In intact limbs, these variables had significantly higher values (+10-35%, pknee kinetics of the prosthetic limb, which suggests a protective mechanism. Knee kinetics of the intact limb did alter, which suggests a compensatory mechanism.

  3. Tissue concentrations of somatomedin C: further evidence for multiple sites of synthesis and paracrine or autocrine mechanisms of action.

    OpenAIRE

    D'Ercole, A J; Stiles, A D; Underwood, L E

    1984-01-01

    We have validated a method for extracting and measuring the tissue content of somatomedin C (Sm-C)/insulin-like growth factor I (IGF-I), a growth-hormone-dependent, growth-promoting peptide. The Sm-C content of tissue extracts was strongly growth-hormone dependent because most of the tissues studied from hypophysectomized rats contained significantly less Sm-C than normal tissues. The intraperitoneal administration of ovine growth hormone (oGH) to hypophysectomized rats caused tissue extracta...

  4. Evolutionary Mechanisms Involved in Emergence of Viral Haemorrhagic Septicaemia Virus (VHSV) into Cultured Rainbow Trout, Oncorhynchus mykiss

    DEFF Research Database (Denmark)

    Schönherz, Anna A.

    Viral haemorrhagic septicaemaia virus (VHSV) is an RNA virus of lower vertebrates that infects a wide range of freshwater, anadromous and marine fish species. VHSV is endemic among most marine and anadromous fish species but has emerged into cultured rainbow trout where it evolves towards high...... virulence, causing extensive losses to the aquacultre industry. Cross-species transmission and subsequent adaptation to cultured raibow trout is observed occasionally. However, the biological background facilitationg VHSV emergense has yet to be identified. In the present PhD project potential mechanisms...... facilitation VHSV emergence into cultured raibow trout were explored. In vivo infection trials and in selico based molecular analysis were performed to independently investigate the first two steps of viral emergence, namely initial introduction to- and subsequent adaptation and establishment within the new...

  5. Mechanisms involved in the depolarization of cutaneous afferents produced by segmental and descending inputs in the cat spinal cord.

    Science.gov (United States)

    Jiménez, I; Rudomin, P; Solodkin, M

    1987-01-01

    The relative contribution of specific and unspecific (potassium) components involved in the generation of primary afferent depolarization (PAD) of cutaneous fibres was analyzed in the spinal cord of the anesthetized cat. To this end we examined the correlation between the intraspinal threshold changes of single afferent fibres in the sural nerve produced by segmental and descending inputs and the negative DC potential shifts produced by these same stimuli at the site of excitability testing, the latter taken as indicators of the changes in extracellular concentration of potassium ions. Stimulation of the ipsilateral brain-stem reticular formation and of the contralateral red nucleus with 100-200 Hz trains reduced very effectively the intraspinal threshold of sural nerve fibres ending in the dorsal horn practically without producing any negative DC potential shifts at the site of excitability testing. However, negative DC potential shifts were produced more ventrally, in the intermediate nucleus and/or motor nucleus. Stimulation of the sural and superficial peroneus nerves with pulses at 2 Hz and strengths below 2 xT, also reduced the intraspinal threshold of single SU fibres without producing significant DC potential changes at the site of excitability testing. On the other hand, 100 Hz trains with strengths above 2 xT produced negative DC potential shifts and a proportional reduction of the intraspinal threshold of the SU fibres. The PAD of sural fibres produced by stimulation of rubro-spinal and reticulo-spinal fibres as well as by stimulation of sensory nerves with low frequency trains was unaffected or slightly increased, by i.v. injection of strychnine (0.2 mg/kg), but was readily abolished 5-10 min after the i.v. injection of picrotoxin (2 mg/kg). The results suggest that activation of reticulo-spinal and rubro-spinal fibres, as well as stimulation of cutaneous nerves with low frequencies and low strengths, produce PAD of cutaneous fibres involving activation

  6. Multiple insecticide resistance mechanisms involving metabolic changes and insensitive target sites selected in anopheline vectors of malaria in Sri Lanka

    Directory of Open Access Journals (Sweden)

    Karunaratne SHP Parakrama

    2008-08-01

    Full Text Available Abstract Background The current status of insecticide resistance and the underlying resistance mechanisms were studied in the major vector of malaria, Anopheles culicifacies, and the secondary vector, Anopheles subpictus in five districts (Anuradhapura, Kurunegala, Moneragala, Puttalam and Trincomalee of Sri Lanka. Eight other anophelines, Anopheles annularis, Anopheles barbirostris, Anopheles jamesii, Anopheles nigerrimus, Anopheles peditaeniatus, Anopheles tessellatus, Anopheles vagus and Anopheles varuna from Anuradhapura district were also tested. Methods Adult females were exposed to the WHO discriminating dosages of DDT, malathion, fenitrothion, propoxur, λ-cyhalothrin, cyfluthrin, cypermethrin, deltamethrin, permethrin and etofenprox. The presence of metabolic resistance by esterase, glutathione S-transferase (GST and monooxygenase-based mechanisms, and the sensitivity of the acetylcholinesterase target site were assessed using synergists, and biochemical, and metabolic techniques. Results All the anopheline species had high DDT resistance. All An. culicifacies and An. subpictus populations were resistant to malathion, except An. culicifacies from Kurunegala, where there was no malathion carboxylesterase activity. Kurunegala and Puttalam populations of An. culicifacies were susceptible to fenitrothion. All the An. culicifacies populations were susceptible to carbamates. Both species were susceptible to the discriminating dosages of cypermethrin and cyfluthrin, but had different levels of resistance to other pyrethroids. Of the 8 other anophelines, only An. nigerrimus and An. peditaeniatus were resistant to all the insecticides tested, probably due to their high exposure to the insecticides used in agriculture. An. vagus showed some resistance to permethrin. Esterases, GSTs and monooxygenases were elevated in both An. culicifacies and An. subpictus. AChE was most sensitive to insecticides in Kurunegala and Trincomalee An. culicifacies

  7. From simple receptors to complex multimodal percepts: A first global picture on the mechanisms involved in perceptual binding

    Directory of Open Access Journals (Sweden)

    Rosemarie eVelik

    2012-07-01

    Full Text Available The binding problem in perception is concerned with answering the question how information from millions of sensory receptors, processed by millions of neurons working in parallel, can be merged into a unified percept. Binding in perception reaches from the lowest levels of feature binding up to the levels of multimodal binding of information coming from the different sensor modalities and also from other functional systems. The last 40 years of research have shown that the binding problem cannot be solved easily. Today, it is considered as one of the key questions to brain understanding. To date, various solutions have been suggested to the binding problem including: (1 combination coding, (2 binding by synchrony, (3 population coding, (4 binding by attention, (5 binding by knowledge, expectation, and memory, (6 hardwired versus on-demand binding, (7 bundling and binding of features, (8 the feature-integration theory of attention, (9 synchronization through top-down processes. Each of those hypotheses addresses important aspects of binding. However, each of them also suffers from certain weak points and can never give a complete explanation. This article gives a brief overview of the so far suggested solutions of perceptual binding and then shows that those are actually not mutually exclusive but can complement each other. A computationally verified model is presented which shows that, most likely, the different described mechanisms of binding act (1 at different hierarchical levels and (2 in different stages of perceptual knowledge acquisition. The model furthermore considers and explains a number of inhibitory filter mechanisms that suppress the activation of inappropriate or currently irrelevant information.

  8. A unique mechanism of nuclear division in Giardia lamblia involves components of the ventral disk and the nuclear envelope.

    Science.gov (United States)

    Solari, Alberto J; Rahn, Monica I; Saura, Alicia; Lujan, Hugo D

    2003-12-01

    The fine structure of the binucleate, parasitic protist Giardia lamblia during interphase and divisional stages was studied by serial thin sectioning and three-dimensional reconstructions. The earlier sign of nuclear division is the development of a few peripheral areas of densely packed chromatin directly attached to the inner nuclear envelope. An intracytoplasmic sheet of ventral disk components grows from the cell periphery towards one of the nuclei, apparently constricting this nucleus, which becomes located at a ventral bulge. After the basal bodies become duplicated, a full nuclear division occurs in trophozoites, giving two pairs of parent-daughter nuclei. This full division occurs in a dorsal-ventral direction, with the resulting nuclear pairs located at the sides of the two sets of basal bodies. A new ventral disk is formed from the disk-derived sheets in the cell harboring the four nuclei. Cytokinesis is polymorphic, but at early stages is dorsal-to-dorsal. Encysting trophozoites show the development of Golgi cisternae stacks and dense, specific secretory granules. 3-D reconstructions show that cysts contain a single pair of incompletely strangled nuclei. The dividing Giardia lacks a typical, microtubular spindle either inside or outside the nuclei. The nuclear envelope seems to be the only structure involved in the final division of the parent-daughter nuclei.

  9. Molecular mechanisms involved in TFF3 peptide-mediated modulation of the E-cadherin/catenin cell adhesion complex.

    Science.gov (United States)

    Meyer zum Büschenfelde, Dirk; Hoschützky, Heinz; Tauber, Rudolf; Huber, Otmar

    2004-05-01

    TFF3 is a member of the TFF-domain peptide family which is constitutively expressed in mucous epithelial tissues where it acts as a motogenic factor and plays an important role during epithelial restitution after wounding and during inflammation. In contrast to these beneficial functions, TFFs were also reported to be involved in cell scattering and tumor invasion. These changes in epithelial cell morphology and motility are associated with a modulation of cell contacts. In this respect, we here investigated the E-cadherin/catenin cell adhesion complex in FLAG-hTFF3-transfected HT29/B6 and MDCK cells. In hTFF3-transfected cells the amount of E-cadherin is reduced with a concomitant reduction of alpha- and beta-catenin levels. On one hand, E-cadherin expression is lowered at the transcriptional level as shown by multiplex RT-PCR analysis. This decrease does not depend on differences in the promoter methylation status as shown by methylation-specific PCR. On the other hand, pulse-chase experiments showed a reduction in the E-cadherin half-life in hTFF3-transfected cells reflecting increased E-cadherin degradation. In summary, hTFF3 induces transcriptional and posttranslational processes resulting in a modulation of E-cadherin-mediated cell-cell contacts that may play an important role in the paradoxical benefical and pathogenic function of TFF peptides.

  10. Intraocular Pressure and the Mechanisms Involved in Resistance of the Aqueous Humor Flow in the Trabecular Meshwork Outflow Pathways.

    Science.gov (United States)

    Tamm, Ernst R; Braunger, Barbara M; Fuchshofer, Rudolf

    2015-01-01

    Intraocular pressure (IOP), the critical risk factor for glaucoma, is generated and maintained by the aqueous humor circulation system. Aqueous humor is secreted from the epithelial layers of the ciliary body and exits the eye through the trabecular meshwork or the uveoscleral outflow pathways. IOP builds up in response to a resistance to aqueous humor flow in the trabecular outflow pathways. The trabecular outflow resistance is localized in the inner wall region, which comprises the juxtacanalicular connective tissue (JCT) and the inner wall endothelium of Schlemm's canal (SC). Outflow resistance in this region is lowered through the relaxation of contractile myofibroblast-like cells in trabecular meshwork and the adjacent scleral spur, or the contraction of the ciliary muscle. In primary open-angle glaucoma, the most frequent form of glaucoma, outflow resistance of the inner wall region is typically higher than normal. There is evidence that the increase in resistance is related to characteristic biological changes in the resident cells of the JCT, which more and more acquire the structural and functional characteristics of contractile myofibroblasts. The changes involve an augmentation of their actin cytoskeleton and of their surrounding fibrillary extracellular matrix, which connects to JCT cells via integrins. This scenario leads to an overall stiffening of the inner wall region, and is modulated by transforming growth factor-β/connective tissue growth factor signaling. Essentially comparable changes appear to occur in SC endothelial cells. Stiffening of JCT and SC cells is very likely a critical causative factor for the increase in trabecular outflow resistance in POAG.

  11. Nandrolone and stanozolol induce Leydig cell tumor proliferation through an estrogen-dependent mechanism involving IGF-I system.

    Science.gov (United States)

    Chimento, Adele; Sirianni, Rosa; Zolea, Fabiana; De Luca, Arianna; Lanzino, Marilena; Catalano, Stefania; Andò, Sebastiano; Pezzi, Vincenzo

    2012-05-01

    Several substances such as anabolic androgenic steroids (AAS), peptide hormones like insulin-like growth factor-I (IGF-I), aromatase inhibitors and estrogen antagonists are offered via the Internet, and are assumed without considering the potential deleterious effects that can be caused by their administration. In this study we aimed to determine if nandrolone and stanozolol, two commonly used AAS, could have an effect on Leydig cell tumor proliferation and if their effects could be potentiated by the concomitant use of IGF-I. Using a rat Leydig tumor cell line, R2C cells, as experimental model we found that nandrolone and stanozolol caused a dose-dependent induction of aromatase expression and estradiol (E2) production. When used in combination with IGF-I they were more effective than single molecules in inducing aromatase expression. AAS exhibited estrogenic activity and induced rapid estrogen receptor (ER)-dependent pathways involving IGF1R, AKT, and ERK1/2 phosphorylation. Inhibitors for these kinases decreased AAS-dependent aromatase expression. Up-regulated aromatase levels and related E2 production increased cell proliferation as a consequence of increased cyclin E expression. The observation that ER antagonist ICI182,780 was also able to significantly reduce ASS- and AAS + IGF-induced cell proliferation, confirmed a role for estrogens in AAS-dependent proliferative effects. Taken together these data clearly indicate that the use of high doses of AAS, as it occurs in doping practice, enhances Leydig cell proliferation, increasing the risk of tumor development. This risk is higher when AAS are used in association with IGF-I. To our knowledge this is the first report directly associating AAS and testicular cancer.

  12. Swarming mechanisms in the yellow fever mosquito: aggregation pheromones are involved in the mating behavior of Aedes aegypti.

    Science.gov (United States)

    Fawaz, Emadeldin Y; Allan, Sandra A; Bernier, Ulrich R; Obenauer, Peter J; Diclaro, Joseph W

    2014-12-01

    Mosquitoes of various species mate in swarms comprised of tens of thousands of flying males. In this study, we examined Aedes aegypti swarming behavior and identified associated chemical cues. Novel evidence is provided that Ae. aegypti females aggregate by means of olfactory cues, such as aggregation pheromones. Isolation of Ae. aegypti aggregation pheromones was achieved by aeration of confined mosquitoes and collection of associated volatiles by glass filters. The collected volatiles were identified through gas chromatography mass spectrometry (GCMS). Three aggregation pheromones were collected and identified as 2,6,6-trimethylcyclohex-2-ene-1,4-dione (ketoisophorone) (CAS# 1125-21-9, t(R) = 18.75), 2,2,6-trimethylcyclohexane-1,4-dione (the saturated analog of ketoisophorone) (CAS# 20547-99-3, t(R) = 20.05), and 1-(4-ethylphenyl) ethanone (CAS# 937-30-4, t(R) = 24.22). Our biological studies revealed that the identified compounds stimulated mosquito behavior under laboratory conditions. The mechanism of mosquito swarm formation is discussed in light of our behavioral study findings. A preliminary field trial demonstrated the potential application of the isolated aggregation pheromones in controlling Ae. aegypti.

  13. Design and evaluation of doxorubicin-containing microbubbles for ultrasound-triggered doxorubicin delivery: cytotoxicity and mechanisms involved.

    Science.gov (United States)

    Lentacker, Ine; Geers, Bart; Demeester, Joseph; De Smedt, Stefaan C; Sanders, Niek N

    2010-01-01

    Drug delivery with microbubbles and ultrasound is gaining more and more attention in the drug delivery field due to its noninvasiveness, local applicability, and proven safety in ultrasonic imaging techniques. In this article, we tried to improve the cytotoxicity of doxorubicin (DOX)-containing liposomes by preparing DOX-liposome-containing microbubbles for drug delivery with therapeutic ultrasound. In this way, the DOX release and uptake can be restricted to ultrasound-treated areas. Compared to DOX-liposomes, DOX-loaded microbubbles killed at least two times more melanoma cells after exposure to ultrasound. After treatment of the melanoma cells with DOX-liposome-loaded microbubbles and ultrasound, DOX was mainly present in the nuclei of the cancer cells, whereas it was mainly detected in the cytoplasm of cells treated with DOX-liposomes. Exposure of cells to DOX-liposome-loaded microbubbles and ultrasound caused an almost instantaneous cellular entry of the DOX. At least two mechanisms were identified that explain the fast uptake of DOX and the superior cell killing of DOX-liposome-loaded microbubbles and ultrasound. First, exposure of DOX-liposome-loaded microbubbles to ultrasound results in the release of free DOX that is more cytotoxic than DOX-liposomes. Second, the cellular entry of the released DOX is facilitated due to sonoporation of the cell membranes. The in vitro results shown in this article indicate that DOX-liposome-loaded microbubbles could be a very interesting tool to obtain an efficient ultrasound-controlled DOX delivery in vivo.

  14. Enhancement of pulmonary tumour seeding by human coagulation factors II, IX, X--an investigation into the possible mechanisms involved.

    Science.gov (United States)

    Purushotham, A D; McCulloch, P; George, W D

    1991-09-01

    Warfarin inhibits metastasis in the animal model and injection of the Warfarin-dependent coagulation factor complex II, IX, X enhances pulmonary metastasis in the same model. We have studied two possible mechanisms responsible for the observed effect. Mtln3, rat mammary carcinoma cells, radiolabelled with 5-(125) Iodo-2'-deoxyuridine (IUDR) were injected intravenously in female Fisher 344 rats either alone or in combination with factor complex II, IX, X or bovine serum albumin. Following sacrifice at various intervals, measured lung radioactivity was significantly higher (20%) in animals administered cells with the factor complex than in the other two groups (P less than 0.001, ANOVA and Student's t-test). These results indicate increased entrapment of tumour cells in the pulmonary microcirculation. In a second experiment, rat factor complex II, IX, X was prepared, and Mtln3 cells were then injected in female Fisher 344 rats alone or in combination with either human factor complex or rat factor complex. Following sacrifice, the number of pulmonary nodules in animals receiving cells with rat factor complex was similar to that in animals receiving human factor complex, and significantly higher than that in the control (P less than 0.001, ANOVA and Mann-Whitney), indicating that the observed enhancement of pulmonary seeding is unrelated to the xenogeneic properties of the human factor complex.

  15. A Tribolium castaneum whole-embryo culture protocol for studying the molecular mechanisms and morphogenetic movements involved in insect development.

    Science.gov (United States)

    Macaya, Constanza C; Saavedra, Patricio E; Cepeda, Rodrigo E; Nuñez, Viviana A; Sarrazin, Andres F

    2016-01-01

    The development of the red flour beetle Tribolium castaneum is more representative of arthropods than the evolutionarily derived fly, Drosophila melanogaster. Thus, Tribolium is becoming an emerging organism model for studying the evolution of the mechanisms that control embryonic development in arthropods. In this regard, diverse genetic and molecular tools are currently available for Tribolium, as well as imaging and embryonic techniques. Recently, we developed a method for culturing embryos in order to study specific stages during Tribolium development. In this report, we present a detailed and "easy-to-follow" protocol for embryo handling and dissection, extending the use of whole-embryo culture to functional analysis by performing in vivo pharmacological manipulations. This experimental accessibility allowed us to study the relevance of microtubules in axis elongation, using nocodazole and taxol drugs to interfere with microtubule networks, followed by length measurement analysis. Additionally, we demonstrated that embryo handling had no effect on the development of Tribolium embryos, and we checked viability after dissection and bisection and during incubation using propidium iodide. The embryo culture protocol we describe here can be applied to study diverse developmental processes in Tribolium. We expect that this protocol can be adapted and applied to other arthropods.

  16. Effect of selenium on control of postharvest gray mould of tomato fruit and the possible mechanisms involved

    Directory of Open Access Journals (Sweden)

    Zhilin eWu

    2016-01-01

    Full Text Available Selenium (Se has important benefits for crop growth and stress tolerance at low concentrations. However, there is very little information on antimicrobial effect of selenium against the economically important fungus Botrytis cinerea. In the present study, using sodium selenite as Se source, we investigated the effect of Se salts on spore germination and mycelial growth of the fungal pathogen in vitro and gray mould control in harvested tomato fruit. Se treatment at 24 mg/L significantly inhibited spore germination of the fungal pathogen and effectively controlled gray mould in harvested tomato fruit. Se treatment at 24 mg/L seems to induce the generation of intracellular reactive oxygen species in the fungal spores. The membrane integrity damage was observed with fluorescence microscopy following staining with propidium iodide after treatment of the spores with Se. These results suggest that Se has the potential for controlling gray mould rot of tomato fruits and might be useful in integrated control against gray mould disease of postharvest fruits and vegetables caused by B. cinerea. The mechanisms by which Se decreased gray mould decay of tomato fruit may be directly related to the severe damage to the conidia plasma membrane and loss of cytoplasmic materials from the hyphae.

  17. Cordycepin Decreases Compound Action Potential Conduction of Frog Sciatic Nerve In Vitro Involving Ca2+-Dependent Mechanisms

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    Li-Hua Yao

    2015-01-01

    Full Text Available Cordycepin has been widely used in oriental countries to maintain health and improve physical performance. Compound nerve action potential (CNAP, which is critical in signal conduction in the peripheral nervous system, is necessary to regulate physical performance, including motor system physiological and pathological processes. Therefore, regulatory effects of cordycepin on CNAP conduction should be elucidated. In this study, the conduction ability of CNAP in isolated frog sciatic nerves was investigated. Results revealed that cordycepin significantly decreased CNAP amplitude and conductive velocity in a reversible and concentration-dependent manner. At 50 mg/L cordycepin, CNAP amplitude and conductive velocity decreased by 62.18 ± 8.06% and 57.34% ± 6.14% compared with the control amplitude and conductive velocity, respectively. However, the depressive action of cordycepin on amplitude and conductive velocity was not observed in Ca2+-free medium or in the presence of Ca2+ channel blockers (CdCl2/LaCl3. Pretreatment with L-type Ca2+ channel antagonist (nifedipine/deltiazem also blocked cordycepin-induced responses; by contrast, T-type and P-type Ca2+ channel antagonists (Ni2+ failed to block such responses. Therefore, cordycepin decreased the conduction ability of CNAP in isolated frog sciatic nerves via L-type Ca2+ channel-dependent mechanism.

  18. PLAG1 alterations in lipoblastoma: involvement in varied mesenchymal cell types and evidence for alternative oncogenic mechanisms.

    Science.gov (United States)

    Gisselsson, D; Hibbard, M K; Dal Cin, P; Sciot, R; Hsi, B L; Kozakewich, H P; Fletcher, J A

    2001-09-01

    Lipoblastomas are rare soft tissue tumors that occur primarily in young children. They typically contain variably differentiated adipocytes, primitive mesenchymal cells, myxoid matrix, and fibrous trabeculae. Abnormalities in chromosome 8, leading to rearrangements of the PLAG1 gene, were demonstrated recently in four lipoblastomas. In the present report, we determine the frequency of PLAG1 alterations in 16 lipoblastomas from children aged 13 years or younger, and we also evaluate the stages of lipoblastoma differentiation at which PLAG1 genomic alterations are found. Eleven lipoblastomas (69%), including those with either classic or lipoma-like histology, had rearrangements of the 8q12 PLAG1 region. Another three lipoblastomas had polysomy for chromosome 8 in the absence of PLAG1 rearrangement. Only two cases (13%) lacked a chromosome 8 abnormality. Notably, the lipoblastomas with chromosome 8 polysomy had up to five copies of chromosome 8 as an isolated cytogenetic finding in an otherwise diploid cell. We also demonstrate that PLAG1 alterations are found in a spectrum of mesenchymal cell types in lipoblastomas, including lipoblasts, mature adipocytes, primitive mesenchymal cells, and fibroblast-like cells. This finding is consistent with neoplastic origin in a primitive mesenchymal precursor and with variable differentiation to a mature adipocyte end-point. Hence, our studies provide biological validation for the clinical observation that lipoblastomas can evolve into mature, lipoma-like, lesions. They also suggest that PLAG1 dosage alterations caused by polysomy 8 might represent an alternative oncogenic mechanism in lipoblastoma.

  19. Arsenate tolerance mechanism of Oenothera odorata from a mine population involves the induction of phytochelatins in roots.

    Science.gov (United States)

    Kim, Dae-Yeon; Park, Hyun; Lee, Sang-Hwan; Koo, Namin; Kim, Jeong-Gyu

    2009-04-01

    We investigated the arsenate tolerance mechanisms of Oenothera odorata by comparing two populations [i.e., one population from the mine site (MP) and the other population from an uncontaminated site (UP)] via the exposure of hydroponic solution containing arsenate (i.e., 0-50 microM). The MP plants were significantly more tolerant to arsenate than UP plants. The UP plants accumulated more As in their shoots and roots than did the MP plants. The UP plants translocated up to 21 microg g(-1) of As into shoots, whereas MP plants translocated less As (up to 4.5 microg g(-1)) to shoots over all treatments. The results of lipid peroxidation indicated that MP plants were less damaged by oxidative stress than were UP plants. Phytochelatin (PC) content correlated linearly with root As concentration in the MP (i.e., [PCs](root)=1.69x[As](root), r(2)=0.945) and UP (i.e., [PCs](root)=0.89x[As](root), r(2)=0.979) plants. This relationship means that increased PC to As ratio may be associated with increased tolerance. Our results suggest that PC induction in roots plays a critical role in As tolerance of O. odorata.

  20. The β-amyloid protein induces S100β expression in rat hippocampus through a mechanism that involves IL-1

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To explore the effect of β-amyloid protein (Aβ) on S100β expression in rat hippocampus and its mechanisms. Methods At 7 days after bilateral stereotaxis injection of different dose of fibrillar Aβ 25-35 and interluekin-1 receptor antagonist (IL-1ra) into the rat CA1 region, the learning and memory abilities of rats were tested with passive avoidance task. Amyloid deposition was detected by using Congo red staining technique. Nissl staining and immunohistochemical techniques were used to analyze the number of neurons, and GFAP and the S100β expression in hippocampal CA1 region , respectively. Results After fibrillar Aβ injection, the step-through latency of rats was significantly shortened compared to that of the control group. The GFAP positive astrocytes were found surrounding amyloid deposition. Neuronal loss occurred in the pyramidal cell layer of CA1 region. The number of S100β positive cells in Aβ-treated group was significantly increased compared with that in the control group. After IL-1ra injection, the number of S100β positive cells was significantly decreased. Conclusion Intrahippocampal injection of Aβ 25-35 could cause similar pathologic changes of Alzheimer's disease. Aβ 25-35 was capable of up-regulating S100β expression in a dose-dependent manner. The injection of IL-1ra could attenuate the effect of Aβ on S100β expression.

  1. Murine neural stem cells model Hunter disease in vitro: glial cell-mediated neurodegeneration as a possible mechanism involved.

    Science.gov (United States)

    Fusar Poli, E; Zalfa, C; D'Avanzo, F; Tomanin, R; Carlessi, L; Bossi, M; Nodari, L Rota; Binda, E; Marmiroli, P; Scarpa, M; Delia, D; Vescovi, A L; De Filippis, L

    2013-11-07

    Mucopolysaccharidosis type II (MPSII or Hunter Syndrome) is a lysosomal storage disorder caused by the deficit of iduronate 2-sulfatase (IDS) activity and characterized by progressive systemic and neurological impairment. As the early mechanisms leading to neuronal degeneration remain elusive, we chose to examine the properties of neural stem cells (NSCs) isolated from an animal model of the disease in order to evaluate whether their neurogenic potential could be used to recapitulate the early phases of neurogenesis in the brain of Hunter disease patients. Experiments here reported show that NSCs derived from the subventricular zone (SVZ) of early symptomatic IDS-knockout (IDS-ko) mouse retained self-renewal capacity in vitro, but differentiated earlier than wild-type (wt) cells, displaying an evident lysosomal aggregation in oligodendroglial and astroglial cells. Consistently, the SVZ of IDS-ko mice appeared similar to the wt SVZ, whereas the cortex and striatum presented a disorganized neuronal pattern together with a significant increase of glial apoptotic cells, suggesting that glial degeneration likely precedes neuronal demise. Interestingly, a very similar pattern was observed in the brain cortex of a Hunter patient. These observations both in vitro, in our model, and in vivo suggest that IDS deficit seems to affect the late phases of neurogenesis and/or the survival of mature cells rather than NSC self-renewal. In particular, platelet-derived growth factor receptor-α-positive (PDGFR-α+) glial progenitors appeared reduced in both the IDS-ko NSCs and in the IDS-ko mouse and human Hunter brains, compared with the respective healthy controls. Treatment of mutant NSCs with IDS or PDGF throughout differentiation was able to increase the number of PDGFR-α+ cells and to reduce that of apoptotic cells to levels comparable to wt. This evidence supports IDS-ko NSCs as a reliable in vitro model of the disease, and suggests the rescue of PDGFR-α+ glial cells as a

  2. Mechanisms involved in abdominal nociception induced by either TRPV1 or TRPA1 stimulation of rat peritoneum.

    Science.gov (United States)

    Trevisan, Gabriela; Rossato, Mateus F; Hoffmeister, Carin; Oliveira, Sara M; Silva, Cássia R; Matheus, Filipe C; Mello, Gláucia C; Antunes, Edson; Prediger, Rui D S; Ferreira, Juliano

    2013-08-15

    Abdominal pain is a frequent symptom of peritoneal cavity irritation, but little is known about the role of the receptors for irritant substances, transient receptor potential vanilloid 1 (TRPV1) and ankyrin 1 (TRPA1), in this painful condition. Thus, we investigated the abdominal nociception caused by peritoneal stimulation with TRPV1 (capsaicin) and TRPA1 (allyl isothiocyanate, AITC) agonists and their mechanisms in rats. The intraperitoneal (i.p.) injection of either capsaicin or AITC (0.03-10 mg/kg) induced short-term (up to 20 min) and dose-dependent abdominal nociception, and also produced c-fos expression in spinal afferents of the dorsal horn. TRPV1 antagonism prevented (94 ± 4% inhibition) nociception induced by capsaicin but not by AITC. In contrast, the TRPA1 antagonism almost abolished AITC-induced nociception (95 ± 2% inhibition) without altering the capsaicin response. Moreover, nociception induced by either capsaicin or AITC was reduced by the desensitisation of TRPV1-positive sensory fibres with resiniferatoxin (73 ± 18 and 76 ± 15% inhibitions, respectively) and by the NK1 receptor antagonist aprepitant (56 ± 5 and 53 ± 8% inhibitions, respectively). Likewise, the i.p. injections of capsaicin or AITC increased the content of substance P in the peritoneal fluid. Nevertheless, neither the mast cell membrane stabiliser cromoglycate, nor the H1 antagonist promethazine, nor depletion of peritoneal macrophages affected abdominal nociception induced either by capsaicin or AITC. Accordingly, neither capsaicin nor AITC increased the histamine content in the peritoneal fluid or provoked peritoneal mast cell degranulation in vitro. Collectively, our findings suggest that TRPV1 and TRPA1 stimulation in the peritoneum produces abdominal nociception that is mediated by sensory fibres activation.

  3. Sarcoplasmic phospholamban protein is involved in the mechanisms of postresuscitation myocardial dysfunction and the cardioprotective effect of nitrite during resuscitation.

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    Yu Huang

    Full Text Available OBJECTIVES: Sarcoplasmic reticulum (SR Ca(2+-handling proteins play an important role in myocardial dysfunction after acute ischemia/reperfusion injury. We hypothesized that nitrite would improve postresuscitation myocardial dysfunction by increasing nitric oxide (NO generation and that the mechanism of this protection is related to the modulation of SR Ca(2+-handling proteins. METHODS: We conducted a randomized prospective animal study using male Sprague-Dawley rats. Cardiac arrest was induced by intravenous bolus of potassium chloride (40 µg/g. Nitrite (1.2 nmol/g or placebo was administered when chest compression was started. No cardiac arrest was induced in the sham group. Hemodynamic parameters were monitored invasively for 90 minutes after the return of spontaneous circulation (ROSC. Echocardiogram was performed to evaluate cardiac function. Myocardial samples were harvested 5 minutes and 1 hour after ROSC. RESULTS: Myocardial function was significantly impaired in the nitrite and placebo groups after resuscitation, whereas cardiac function (i.e., ejection fraction and fractional shortening was significantly greater in the nitrite group than in the placebo group. Nitrite administration increased the level of nitric oxide in the myocardium 5 min after resuscitation compared to the other two groups. The levels of phosphorylated phospholamban (PLB were decreased after resuscitation, and nitrite increased the phosphorylation of phospholamban compared to the placebo. No significant differences were found in the expression of sarcoplasmic reticulum Ca(2+ ATPase (SERCA2a and ryanodine receptors (RyRs. CONCLUSIONS: postresuscitation myocardial dysfunction is associated with the impairment of PLB phosphorylation. Nitrite administered during resuscitation improves postresuscitation myocardial dysfunction by preserving phosphorylated PLB protein during resuscitation.

  4. Structural and Molecular Mechanism of CdpR Involved in Quorum-Sensing and Bacterial Virulence in Pseudomonas aeruginosa.

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    Jingru Zhao

    2016-04-01

    Full Text Available Although quorum-sensing (QS systems are important regulators of virulence gene expression in the opportunistic human pathogen Pseudomonas aeruginosa, their detailed regulatory mechanisms have not been fully characterized. Here, we show that deletion of PA2588 resulted in increased production of pyocyanin and biofilm, as well as enhanced pathogenicity in a mouse model. To gain insights into the function of PA2588, we performed a ChIP-seq assay and identified 28 targets of PA2588, including the intergenic region between PA2588 and pqsH, which encodes the key synthase of Pseudomonas quinolone signal (PQS. Though the C-terminal domain was similar to DNA-binding regions of other AraC family members, structural studies revealed that PA2588 has a novel fold at the N-terminal region (NTR, and its C-terminal HTH (helix-turn-helix domain is also unique in DNA recognition. We also demonstrated that the adaptor protein ClpS, an essential regulator of ATP-dependent protease ClpAP, directly interacted with PA2588 before delivering CdpR to ClpAP for degradation. We named PA2588 as CdpR (ClpAP-degradation and pathogenicity Regulator. Moreover, deletion of clpP or clpS/clpA promotes bacterial survival in a mouse model of acute pneumonia infection. Taken together, this study uncovered that CdpR is an important QS regulator, which can interact with the ClpAS-P system to regulate the expression of virulence factors and pathogenicity.

  5. Two non-target mechanisms are involved in glyphosate-resistant horseweed (Conyza canadensis L. Cronq.) biotypes.

    Science.gov (United States)

    González-Torralva, Fidel; Rojano-Delgado, Antonia M; Luque de Castro, María D; Mülleder, Norbert; De Prado, Rafael

    2012-11-15

    The physiological and biochemical bases for glyphosate resistance and susceptibility in horseweed (Conyza canadensis L. Cronq.) populations collected from Córdoba, Huelva, Málaga, Jaén and Seville in southern Spain were investigated. Screening 25 populations treated with glyphosate (238gacidequivalentha(-1)) at the rosette stage (BBCH 14-15) revealed reductions in fresh weight (fw) of 9-99%. The resistant biotype (R C004) was 6.1 times more resistant than the susceptible biotype (S). Shikimate accumulation in both biotypes increased until 72h after treatment (HAT), and then continued to increase (to 61.2%) in the S biotype, but decreased by 40% in the R (C004) biotype. Differential glyphosate spray retention and foliar uptake of applied (14)C-glyphosate between the R (C004) and S biotype had no effect on resistance to this herbicide. Quantitative and qualitative tests showed greater (14)C-glyphosate mobility in the S biotype than in the R (C004) biotype. Glyphosate was metabolized faster in the R (C004) biotype than in the S biotype. The herbicide disappeared completely from the R (C004) biotype by conversion into glyoxylate, sarcosine and aminomethylphosphonic acid within 96 HAT. On the other hand, 41.43nmolg(-1)fw of all glyphosate applied remained in the S biotype and glyoxylate was its only non-toxic metabolite. These results suggest that glyphosate resistance in horseweed is due to two different non-target mechanisms, namely: (a) impaired glyphosate translocation and (b) glyphosate metabolism to other compounds.

  6. Regulation of the CDP-choline pathway by sterol regulatory element binding proteins involves transcriptional and post-transcriptional mechanisms.

    Science.gov (United States)

    Ridgway, Neale D; Lagace, Thomas A

    2003-06-15

    The synthesis of phosphatidylcholine (PtdCho) by the CDP-choline pathway is under the control of the rate-limiting enzyme CTP:phosphocholine cytidylyltransferase (CCT). Sterol regulatory element binding proteins (SREBPs) have been proposed to regulate CCT at the transcriptional level, or via the synthesis of lipid activators or substrates of the CDP-choline pathway. To assess the contributions of these two mechanisms, we examined CCTalpha expression and PtdCho synthesis by the CDP-choline pathway in cholesterol and fatty acid auxotrophic CHO M19 cells inducibly expressing constitutively active nuclear forms of SREBP1a or SREBP2. Induction of either SREBP resulted in increased expression of mRNAs for sterol-regulated genes, elevated fatty acid and cholesterol synthesis (>10-50-fold) and increased PtdCho synthesis (2-fold). CCTalpha mRNA was increased 2-fold by enforced expression of SREBP1a or SREBP2. The resultant increase in CCTalpha protein and activity (2-fold) was restricted primarily to the soluble fraction of cells, and increased CCTalpha activity in vivo was not detected. Inhibition of the synthesis of fatty acids or their CoA esters by cerulenin or triacsin C respectively following SREBP induction effectively blocked the accompanying elevation in PtdCho synthesis. Thus PtdCho synthesis was driven by increased synthesis of fatty acids or a product thereof. These data show that transcriptional activation of CCTalpha is modest relative to that of other SREBP-regulated genes, and that stimulation of PtdCho synthesis by SREBPs in CHO cells is due primarily to increased fatty acid synthesis.

  7. Mechanism of hyperinsulinism in short-chain 3-hydroxyacyl-CoA dehydrogenase deficiency involves activation of glutamate dehydrogenase.

    Science.gov (United States)

    Li, Changhong; Chen, Pan; Palladino, Andrew; Narayan, Srinivas; Russell, Laurie K; Sayed, Samir; Xiong, Guoxiang; Chen, Jie; Stokes, David; Butt, Yasmeen M; Jones, Patricia M; Collins, Heather W; Cohen, Noam A; Cohen, Akiva S; Nissim, Itzhak; Smith, Thomas J; Strauss, Arnold W; Matschinsky, Franz M; Bennett, Michael J; Stanley, Charles A

    2010-10-01

    The mechanism of insulin dysregulation in children with hyperinsulinism associated with inactivating mutations of short-chain 3-hydroxyacyl-CoA dehydrogenase (SCHAD) was examined in mice with a knock-out of the hadh gene (hadh(-/-)). The hadh(-/-) mice had reduced levels of plasma glucose and elevated plasma insulin levels, similar to children with SCHAD deficiency. hadh(-/-) mice were hypersensitive to oral amino acid with decrease of glucose level and elevation of insulin. Hypersensitivity to oral amino acid in hadh(-/-) mice can be explained by abnormal insulin responses to a physiological mixture of amino acids and increased sensitivity to leucine stimulation in isolated perifused islets. Measurement of cytosolic calcium showed normal basal levels and abnormal responses to amino acids in hadh(-/-) islets. Leucine, glutamine, and alanine are responsible for amino acid hypersensitivity in islets. hadh(-/-) islets have lower intracellular glutamate and aspartate levels, and this decrease can be prevented by high glucose. hadh(-/-) islets also have increased [U-(14)C]glutamine oxidation. In contrast, hadh(-/-) mice have similar glucose tolerance and insulin sensitivity compared with controls. Perifused hadh(-/-) islets showed no differences from controls in response to glucose-stimulated insulin secretion, even with addition of either a medium-chain fatty acid (octanoate) or a long-chain fatty acid (palmitate). Pull-down experiments with SCHAD, anti-SCHAD, or anti-GDH antibodies showed protein-protein interactions between SCHAD and GDH. GDH enzyme kinetics of hadh(-/-) islets showed an increase in GDH affinity for its substrate, α-ketoglutarate. These studies indicate that SCHAD deficiency causes hyperinsulinism by activation of GDH via loss of inhibitory regulation of GDH by SCHAD.

  8. MeCP2 post-translational modifications: a mechanism to control its involvement in synaptic plasticity and homeostasis?

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    Elisa eBellini

    2014-08-01

    Full Text Available Although Rett syndrome (RTT represents one of the most frequent forms of severe intellectual disability in females worldwide, we still have an inadequate knowledge of the many roles played by MeCP2 (whose mutations are responsible for most cases of RTT and their relevance for RTT pathobiology. Several studies support a role of MeCP2 in the regulation of synaptic plasticity and homeostasis. At the molecular level, MeCP2 is described as a repressor capable of inhibiting gene transcription through chromatin compaction. Indeed, it interacts with several chromatin remodeling factors, such as HDAC-containing complexes and ATRX. Other studies have inferred that MeCP2 functions also as an activator; a role in regulating mRNA splicing and in modulating protein synthesis has also been proposed. Further, MeCP2 avidly binds both 5-methyl- and 5-hydroxymethyl-cytosine. Recent evidence suggests that it is the highly disorganized structure of MeCP2, together with its post-translational modifications (PTMs that generate and regulate this functional versatility. Indeed, several reports have demonstrated that differential phosphorylation of MeCP2 is a key mechanism by which the methyl binding protein modulates its affinity for its partners, gene expression and cellular adaptations to stimuli and neuronal plasticity. As logic consequence, generation of phospho-defective Mecp2 knock-in mice has permitted associating alterations in neuronal morphology, circuit formation, and mouse behavioral phenotypes with specific phosphorylation events. MeCP2 undergoes various other PTMs, including acetylation, ubiquitination and sumoylation, whose functional roles remain largely unexplored. These results, together with the genome-wide distribution of MeCP2 and its capability to substitute histone H1, recall the complex regulation of histones and suggest the relevance of quickly gaining a deeper comprehension of MeCP2 PTMs, the respective writers and readers and the consequent

  9. Alteration in Marrow Stromal Microenvironment and Apoptosis Mechanisms Involved in Aplastic Anemia: An Animal Model to Study the Possible Disease Pathology

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    Sumanta Chatterjee

    2010-01-01

    Full Text Available Aplastic anemia (AA is a heterogeneous disorder of bone marrow failure syndrome. Suggested mechanisms include a primary stem cell deficiency or defect, a secondary stem cell defect due to abnormal regulation between cell death and differentiation, or a deficient microenvironment. In this study, we have tried to investigate the alterations in hematopoietic microenvironment and underlying mechanisms involved in such alterations in an animal model of drug induced AA. We presented the results of studying long term marrow culture, marrow ultra-structure, marrow adherent and hematopoietic progenitor cell colony formation, flowcytometric analysis of marrow stem and stromal progenitor populations and apoptosis mechanism involved in aplastic anemia. The AA marrow showed impairment in cellular proliferation and maturation and failed to generate a functional stromal microenvironment even after 19 days of culture. Ultra-structural analysis showed a degenerated and deformed marrow cellular association in AA. Colony forming units (CFUs were also severely reduced in AA. Significantly decreased marrow stem and stromal progenitor population with subsequently increased expression levels of both the extracellular and intracellular apoptosis inducer markers in the AA marrow cells essentially pointed towards the defective hematopoiesis; moreover, a deficient and apoptotic microenvironment and the microenvironmental components might have played the important role in the possible pathogenesis of AA.

  10. Suppression of ERK phosphorylation through oxidative stress is involved in the mechanism underlying sevoflurane-induced toxicity in the developing brain

    Science.gov (United States)

    Yufune, Shinya; Satoh, Yasushi; Akai, Ryosuke; Yoshinaga, Yosuke; Kobayashi, Yasushi; Endo, Shogo; Kazama, Tomiei

    2016-01-01

    In animal models, neonatal exposure to general anesthetics significantly increased neuronal apoptosis with subsequent behavioral deficits in adulthood. Although the underlying mechanism is largely unknown, involvement of extracellular signal-regulated kinases (ERKs) is speculated since ERK phosphorylation is decreased by neonatal anesthetic exposure. Importance of ERK phosphorylation for neuronal development is underscored by our recent finding that transient suppression of ERK phosphorylation during the neonatal period significantly increased neuronal apoptosis and induced behavioral deficits. However, it is still unknown as to what extent decreased ERK phosphorylation contributes to the mechanism underlying anesthetic-induced toxicity. Here we investigated the causal relationship of decreased ERK phosphorylation and anesthetic-induced toxicity in the developing brain. At postnatal day 6 (P6), mice were exposed to sevoflurane (2%) or the blood-brain barrier-penetrating MEK inhibitor, α-[amino[(4-aminophenyl)thio]methylene]-2-(trifluoromethyl)benzeneacetonitrile (SL327) (50 mg/kg). Transient suppression of ERK phosphorylation by an intraperitoneal injection of SL327 at P6 significantly increased apoptosis similar to sevoflurane-induced apoptosis. Conversely, SL327 administration at P14 or P21 did not induce apoptosis, even though ERK phosphorylation was inhibited. Restoring ERK phosphorylation by administration of molecular hydrogen ameliorated sevoflurane-induced apoptosis. Together, our results strongly suggests that suppressed ERK phosphorylation is critically involved in the mechanism underlying anesthetic-induced toxicity in the developing brain. PMID:26905012

  11. Signal transduction mechanisms involved in S100A4-induced activation of the transcription factor NF-κB

    Directory of Open Access Journals (Sweden)

    Mælandsmo Gunhild M

    2010-05-01

    Full Text Available Abstract Background The metastasis-promoting protein S100A4 activates the transcription factor NF-κB through the classical NF-κB activation pathway. The upstream signal transduction mechanisms leading to increased NF-κB activity are, however, incompletely characterized. Methods The human osteosarcoma cell line II-11b was stimulated with recombinant S100A4 in the presence or absence of inhibitors of common signal transduction pathways, and NF-κB activity was examined using a luciferase-based reporter assay and phosphorylation of IκBα. mRNA expression was analyzed by real-time RT-PCR, protein expression was examined by Western blotting and IKK activity was measured using an in vitro kinase assay. The role of upstream kinases and the cell surface receptor RAGE was investigated by overexpression of dominant negative proteins and by siRNA transfection. Results The Ser/Thr kinase inhibitors H-7 and staurosporine inhibited S100A4-induced IκBα phosphorylation and subsequent NF-κB activation. The protein tyrosine kinase inhibitor genistein and the phospholipase C inhibitor compound 48/80 had a partial inhibitory effect on IκBα phosphorylation, whereas inhibitors of protein kinase C, G-protein coupled receptors and PI 3-kinases had no effect on the level of phosphorylation. Interestingly, S100A4 treatment induced activating phosphorylations of IKKα/β, but neither H-7 nor staurosporine was able to significantly inhibit IKK activation. Dominant negative MEKK1 or NIK did not inhibit S100A4-induced NF-κB activity, and S100A4 stimulation did not influence AKT phosphorylation. Furthermore, diminished expression of the putative S100 protein receptor RAGE did not affect the observed phosphorylation of IκBα. Conclusions S100A4 activates NF-κB by inducing phosphorylation of IKKα/β, leading to increased IκBα phosphorylation. The Ser/Thr kinase inhibitors H-7 and staurosporine attenuated S100A4-induced NF-κB activation and inhibited IKK

  12. Characterization of mechanisms involved in presynaptic inhibition of sympathetic pressor effects induced by some 5-HT1 receptor antagonists.

    Science.gov (United States)

    Fernández, M M; Calama, E; Morán, A; Martín, M L; San Román, L

    2000-01-01

    1. In a previous study, we showed that the presynaptic inhibitory action of 5-hydroxytryptamine receptor agonists on sympathetic pressor effects obtained in the pithed rats were mainly mediated by activation of 5-HT1A and 5-HT1D receptor subtypes. At the time, we observed that some 5-HT1 receptors antagonists - WAY 100,635 and NAN-190 (both 5-HT1A receptor antagonists), methiothepin (a 5-HT1,2,5,6,7 receptor antagonist) and spiperone (a 5-HT1,2 receptor antagonist) - reduced per se the pressor effects obtained by electrical stimulation. The aim of the present work was to investigate the mechanism participating in this inhibitory effect. 2. The inhibition induced by WAY 100,635 (1000 microg kg-1, i.v.) was blocked after i.v. treatment with idazoxan, an alpha2-adrenoceptor antagonist (300 and 1000 microg kg-1) and was not modified after i.v. treatment with propranolol, a beta-adrenoceptor antagonist (1000 microg kg-1) and sulpiride, a D2 receptor antagonist (1000 microg kg-1). The inhibition induced by spiperone (500 microg kg-1 i.v.) was significantly blocked by sulpiride (1000 microg kg-1) and was not modified by idazoxan or propranolol. 3. Sulpiride (1000 microg kg-1) partially blocked the inhibition induced by methiothepin (50 microg kg-1 i.v.). Only pretreatment with idazoxan (300 microg kg-1) modified the inhibition induced by NAN-190 (100 microg kg-1 i.v.), such inhibition increasing after intravenous administration of idazoxan. 4. All the antagonists used in our experiments failed to inhibit the pressor responses elicited by i.v. noradrenaline administration. 5. The above results suggest that the inhibitory effects of these 5-HT1 receptor antagonists are presynaptic in nature, but not related to the blockade of 5-HT1 receptors subtypes. The simultaneous activation or inhibition of other receptor systems could explain the inhibition produced by each 5-HT1 receptor antagonist studied.

  13. The ectomycorrhizal fungus Paxillus involutus converts organic matter in plant litter using a trimmed brown-rot mechanism involving Fenton chemistry

    DEFF Research Database (Denmark)

    Rineau, Francois; Roth, Doris; Shah, Firoz

    2012-01-01

    chemistry similar to that of brown-rot fungi. The set of enzymes expressed by Pa. involutus during the degradation of the organic matter was similar to the set of enzymes involved in the oxidative degradation of wood by brown-rot fungi. However, Pa. involutus lacked transcripts encoding extracellular...... the mycorrhizal fungi. To capture the nitrogen, the fungi must at least partly disrupt the recalcitrant organic matterprotein complexes within which the nitrogen is embedded. This disruption process is poorly characterized. We used spectroscopic analyses and transcriptome profiling to examine the mechanism...... by which the ectomycorrhizal fungus Paxillus involutus degrades organic matter when acquiring nitrogen from plant litter. The fungus partially degraded polysaccharides and modified the structure of polyphenols. The observed chemical changes were consistent with a hydroxyl radical attack, involving Fenton...

  14. Modification of hydrological properties in a fine textured soil following field application of pelletized biochar: investigation of the mechanism involved.

    Science.gov (United States)

    Costanza Andrenelli, Maria; Mocali, Stefano; Pellegrini, Sergio; Vignozzi, Nadia

    2016-04-01

    The application of pelletized biochar is seldom employed in field, and its effect on soil hydrological behaviour scarcely investigated. Biochar is usually added in powdered or granular form to improve the homogeneity of distribution, meanwhile favouring its interaction with soil matrix. In this study we evaluated the possibility of applying pelletized biochar as soil conditioner to enhance, during a single cropping season, the hydrological behaviour of a silty clay loam soil prone to structure degradation. For that purpose, the water retention curves (WRCs) were determined on undisturbed soil samples (0-15 cm) three months after the addition, at the rate of 14 Mg ha-1, of two differently pyrolyzed biochars (B1 and B2). Starting from the WRCs the pore size distribution was determined. The gravimetric water content at both field capacity (-10 kPa) and wilting point (-1,500 kPa) was also measured on biochar samples to assess their available water capacity (AWC). In both the treatments, soil bulk density (BD) was significantly lower compared to control, apparently as direct consequence of the addition of low density pellets. Actually, excluding the intrinsic biochar porosity from soil bulk density calculation, BD values of the treated soils remain lower of around 10% over control. Such findings suggest that a modification of soil structural characteristics might have been induced by pellet addition. Data of the WRCs indicate a significant increase of transmission (500-50 micron), storage (50-0.5 micron) and AWC pores (30-0.2 micron) in the amended soils. The two biochars affected the AWC by direct pore contribution, but the extent of such effect was related to the biochar type: the tested pelletized biomass seems to have positive effects provided that the pyrolysis temperature does not exceed 800°C, as in the case of B1. The overall hydrological improvement might be correlated to both the inherent biochar retention capacity and a merely mechanical process of

  15. Genotoxic potential of montmorillonite clay mineral and alteration in the expression of genes involved in toxicity mechanisms in the human hepatoma cell line HepG2.

    Science.gov (United States)

    Maisanaba, Sara; Hercog, Klara; Filipic, Metka; Jos, Ángeles; Zegura, Bojana

    2016-03-01

    Montmorillonite, also known as Cloisite(®)Na(+) (CNa(+)), is a natural clay with a wide range of well-documented and novel applications, such as pharmaceutical products or food packaging. Although considered a low toxic product, the expected increased exposure to CNa(+) arises concern on the potential consequences on human and environmental health especially as its genotoxicity has scarcely been investigated so far. Thus, we investigated, for the first time, the influence of non-cytotoxic concentrations of CNa(+) (15.65, 31.25 and 62.5 μg/mL) on genomic instability of human hepatoma cell line (HepG2) by determining the formation of micronuclei (MNi), nucleoplasmic bridges (NPBs) and nuclear buds (NBUDs) with the Cytokinesis block micronucleus cytome assay. Further on we studied the influence of CNa(+) on the expression of several genes involved in toxicity mechanisms using the real-time quantitative PCR. The results showed that CNa(+) increased the number of MNi, while the numbers of NBUDs and NPBs were not affected. In addition it deregulated genes in all the groups studied, mainly after longer time of exposure. These findings provide the evidence that CNa(+) is potentially genotoxic. Therefore further studies that will elucidate the molecular mechanisms involved in toxic activity of CNa(+) are needed for hazard identification and human safety assessment.

  16. Activation of vitamin D regulates response of human bronchial epithelial cells to Aspergillus fumigatus in an autocrine fashion.

    Science.gov (United States)

    Li, Pei; Wu, Ting; Su, Xin; Shi, Yi

    2015-01-01

    Aspergillus fumigatus (A. fumigatus) is one of the most common fungi to cause diseases in humans. Recent evidence has demonstrated that airway epithelial cells play an important role in combating A. fumigatus through inflammatory responses. Human airway epithelial cells have been proven to synthesize the active vitamin D, which plays a key role in regulating inflammation. The present study was conducted to investigate the impact of A. fumigatus infection on the activation of vitamin D and the role of vitamin D activation in A. fumigatus-elicited antifungal immunity in normal human airway epithelial cells. We found that A. fumigatus swollen conidia (SC) induced the expression of 1α-hydroxylase, the enzyme catalyzing the synthesis of active vitamin D, and vitamin D receptor (VDR) in 16HBE cells and led to increased local generation of active vitamin D. Locally activated vitamin D amplified SC-induced expression of antimicrobial peptides in 16HBE cells but attenuated SC-induced production of cytokines in an autocrine fashion. Furthermore, we identified β-glucan, the major A. fumigatus cell wall component, as the causative agent for upregulation of 1α-hydroxylase and VDR in 16HBE cells. Therefore, activation of vitamin D is inducible and provides a bidirectional regulation of the responses to A. fumigatus in 16HBE cells.

  17. Cellular entry of ebola virus involves uptake by a macropinocytosis-like mechanism and subsequent trafficking through early and late endosomes.

    Directory of Open Access Journals (Sweden)

    Mohammad F Saeed

    Full Text Available Zaire ebolavirus (ZEBOV, a highly pathogenic zoonotic virus, poses serious public health, ecological and potential bioterrorism threats. Currently no specific therapy or vaccine is available. Virus entry is an attractive target for therapeutic intervention. However, current knowledge of the ZEBOV entry mechanism is limited. While it is known that ZEBOV enters cells through endocytosis, which of the cellular endocytic mechanisms used remains unclear. Previous studies have produced differing outcomes, indicating potential involvement of multiple routes but many of these studies were performed using noninfectious surrogate systems such as pseudotyped retroviral particles, which may not accurately recapitulate the entry characteristics of the morphologically distinct wild type virus. Here we used replication-competent infectious ZEBOV as well as morphologically similar virus-like particles in specific infection and entry assays to demonstrate that in HEK293T and Vero cells internalization of ZEBOV is independent of clathrin, caveolae, and dynamin. Instead the uptake mechanism has features of macropinocytosis. The binding of virus to cells appears to directly stimulate fluid phase uptake as well as localized actin polymerization. Inhibition of key regulators of macropinocytosis including Pak1 and CtBP/BARS as well as treatment with the drug EIPA, which affects macropinosome formation, resulted in significant reduction in ZEBOV entry and infection. It is also shown that following internalization, the virus enters the endolysosomal pathway and is trafficked through early and late endosomes, but the exact site of membrane fusion and nucleocapsid penetration in the cytoplasm remains unclear. This study identifies the route for ZEBOV entry and identifies the key cellular factors required for the uptake of this filamentous virus. The findings greatly expand our understanding of the ZEBOV entry mechanism that can be applied to development of new

  18. Phosphoglucose isomerase/autocrine motility factor mediates epithelial-mesenchymal transition regulated by miR-200 in breast cancer cells.

    Science.gov (United States)

    Ahmad, Aamir; Aboukameel, Amro; Kong, Dejuan; Wang, Zhiwei; Sethi, Seema; Chen, Wei; Sarkar, Fazlul H; Raz, Avraham

    2011-05-01

    Phosphoglucose isomerase/autocrine motility factor (PGI/AMF) plays an important role in glycolysis and gluconeogenesis and is associated with invasion and metastasis of cancer cells. We have previously shown its role in the induction of epithelial-mesenchymal transition (EMT) in breast cancer cells, which led to increased aggressiveness; however, the molecular mechanism by which PGI/AMF regulates EMT is not known. Here we show, for the first time, that PGI/AMF overexpression led to an increase in the DNA-binding activity of NF-κB, which, in turn, led to increased expression of ZEB1/ZEB2. The microRNA-200s (miR-200s) miR-200a, miR-200b, and miR-200c are known to negatively regulate the expression of ZEB1/ZEB2, and we found that the expression of miR-200s was lost in PGI/AMF overexpressing MCF-10A cells and in highly invasive MDA-MB-231 cells, which was consistent with increased expression of ZEB1/ZEB2. Moreover, silencing of PGI/AMF expression in MDA-MB-231 cells led to overexpression of miR-200s, which was associated with reversal of EMT phenotype (i.e., mesenchymal-epithelial transition), and these findings were consistent with alterations in the relative expression of epithelial (E-cadherin) and mesenchymal (vimentin, ZEB1, ZEB2) markers and decreased aggressiveness as judged by clonogenic, motility, and invasion assays. Moreover, either reexpression of miR-200 or silencing of PGI/AMF suppressed pulmonary metastases of MDA-MB-231 cells in vivo, and anti-miR-200 treatment in vivo resulted in increased metastases. Collectively, these results suggest a role of miR-200s in PGI/AMF-induced EMT and thus approaches for upregulation of miR-200s could be a novel therapeutic strategy for the treatment of highly invasive breast cancer.

  19. A labdane diterpene exerts ex vivo and in vivo cardioprotection against post-ischemic injury: involvement of AKT-dependent mechanisms.

    Science.gov (United States)

    Cuadrado-Berrocal, Irene; Gómez-Gaviro, María V; Benito, Yolanda; Barrio, Alicia; Bermejo, Javier; Fernández-Santos, María Eugenia; Sánchez, Pedro L; Desco, Manuel; Fernández-Avilés, Francisco; Fernández-Velasco, María; Boscá, Lisardo; de Las Heras, Beatriz

    2015-02-15

    Therapeutic approaches to protect the heart from ischemia/reperfusion (I/R) injury are an area of intense research, as myocardial infarction is a major cause of mortality and morbidity. Diterpenes are bioactive natural products with great therapeutic potential. In the present study, we have investigated the in vivo cardioprotective effects of a labdane diterpene (DT1) against cardiac I/R injury and the molecular mechanisms involved. DT1 attenuates post-ischemic injury via an AKT-dependent activation of HIF-1α, survival pathways and inhibition of NF-κB signaling. Myocardial infarction (MI) was induced in Wistar rats occluding the left coronary artery (LCA) for 30min followed by 72h reperfusion. DT1 (5mg/kg) was intravenously administered at reperfusion. In addition, we investigated the mechanisms of cardioprotection in the Langendorff-perfused model. Cardioprotection was observed when DT1 was administered after myocardial injury. The molecular mechanisms involved the activation of the survival pathway PDK-1, AKT and AMPK, a reduced phosphorylation of PKD1/2 and sustained HIF-1α activity, leading to increased expression of anti-apoptotic proteins and decreased caspase-3 activation. Pharmacological inhibition of AKT following MI and prior to DT1 challenge significantly decreased the cardioprotection afforded by DT1 therapy at reperfusion. Cardiac function after MI was significantly improved after DT1-treatment, as evidenced by hemodynamic recovery and decreased myocardial infarct size. These findings demonstrate an efficient in vivo cardioprotection by diterpene DT1 against I/R when administered at reperfusion, opening new therapeutic strategies as adjunctive therapy for the pharmacological management of I/R injury.

  20. Picroside Ⅱ inhibits hypoxia/reoxygenation-induced cardiomyocyte apoptosis by ameliorating mitochondrial function through a mechanism involving a decrease in reactive oxygen species production.

    Science.gov (United States)

    Li, Jian-Zhe; Yu, Shu-Yi; Mo, Dan; Tang, Xiu-Neng; Shao, Qing-Rui

    2015-02-01

    Reactive oxygen species (ROS)‑induced mitochondrial dysfunction plays an important role in cardiomyocyte apoptosis during myocardial ischemia/reperfusion (I/R) injury. Picroside Ⅱ, isolated from Picrorhiza scrophulariiflora Pennell (Scrophulariaceae), has been reported to protect cardiomyocytes from hypoxia/reoxygenation (H/R)‑induced apoptosis, but the exact mechanism is not fully clear. The aim of the present study was to explore the protective effects of picroside Ⅱ on H/R‑induced cardiomyocyte apoptosis and the underlying mechanism. In the H9c2 rat cardiomyocyte cell line, picroside Ⅱ (100 µg/ml) was added for 48 h prior to H/R. The results showed that picroside Ⅱ markedly inhibited H/R‑induced cardiomyocyte apoptosis. In addition, picroside Ⅱ was also able to decrease the opening degree of mitochondrial permeability transition pore (mPTP), increase the mitochondrial membrane potential, inhibit cytochrome c release from mitochondria to cytosol and downregulate caspase‑3 expression and activity concomitantly with the decreased ROS production. These results suggested that picroside Ⅱ inhibited H/R‑induced cardiomyocyte apoptosis by ameliorating mitochondrial function through a mechanism involving a decrease in ROS production.

  1. Role of enzymatic activity in muscle damage and cytotoxicity induced by Bothrops asper Asp49 phospholipase A2 myotoxins: are there additional effector mechanisms involved?

    Directory of Open Access Journals (Sweden)

    Diana Mora-Obando

    2014-09-01

    Full Text Available Viperid venoms often contain mixtures of Asp49 and Lys49 PLA2 myotoxin isoforms, relevant to development of myonecrosis. Given their difference in catalytic activity, mechanistic studies on each type require highly purified samples. Studies on Asp49 PLA2s have shown that enzyme inactivation using p-bromophenacyl bromide (p-BPB drastically affects toxicity. However, based on the variable levels of residual toxicity observed in some studies, it has been suggested that effector mechanisms independent of catalysis may additionally be involved in the toxicity of these enzymes, possibly resembling those of the enzymatically inactive Lys49 myotoxins. A possibility that Lys49 isoforms could be present in Asp49 PLA2 preparations exists and, if undetected in previous studies, could explain the variable residual toxicity. This question is here addressed by using an enzyme preparation ascertained to be free of Lys49 myotoxins. In agreement with previous reports, inactivation of the catalytic activity of an Asp49 myotoxin preparation led to major inhibition of toxic effects in vitro and in vivo. The very low residual levels of myotoxicity (7% and cytotoxicity (4% observed can be attributed to the low, although detectable, enzyme remaining active after p-BPB treatment (2.7%, and would be difficult to reconcile with the proposed existence of additional catalytic-independent toxic mechanisms. These findings favor the concept that the effector mechanism of toxicity of Asp49 PLA2 myotoxins from viperids fundamentally relies on their ability to hydrolyze phospholipids, arguing against the proposal that membrane disruption may also be caused by additional mechanisms that are independent of catalysis.

  2. Involvement of HLDF protein and anti-HLDF antibodies in the mechanisms of blood pressure regulation in healthy individuals and patients with stable hypertension and hypertensive crisis.

    Science.gov (United States)

    Elistratova, E I; Gruden, M A; Sherstnev, V V

    2012-09-01

    We studied the relationships between the blood serum levels of human leukemia differentiation factor HLDF, idiotypic and anti-idiotypic antibodies to HLDF, and clinical indicators of cardiovascular function in apparently healthy individuals and patients with essential hypertension and cerebral hypertensive crisis. Markedly reduced HLDF levels and anti-HLDF antibody titers were found in the blood of the examined patients. Correlations between HLDF levels, duration of hypertension, and systolic and diastolic BP were revealed. These findings suggest that the studied molecular factors are involved in the mechanisms of BP regulation under normal conditions and during hypertension development. The protein HLDF and anti-HLDF antibodies can be considered as biomarkers for early diagnosis of hypertension and its cerebral complications.

  3. The Three-Dimensional Structure of NAD(P)H:Quinone Reductase, a Flavoprotein Involved in Cancer Chemoprotection and Chemotherapy: Mechanism of the Two-Electron Reduction

    Science.gov (United States)

    Li, Rongbao; Bianchet, Mario A.; Talalay, Paul; Amzel, L. Mario

    1995-09-01

    Quinone reductase [NAD(P)H:(quinone acceptor) oxidoreductase, EC 1.6.99.2], also called DT diaphorase, is a homodimeric FAD-containing enzyme that catalyzes obligatory NAD(P)H-dependent two-electron reductions of quinones and protects cells against the toxic and neoplastic effects of free radicals and reactive oxygen species arising from one-electron reductions. These two-electron reductions participate in the reductive bioactivation of cancer chemotherapeutic agents such as mitomycin C in tumor cells. Thus, surprisingly, the same enzymatic reaction that protects normal cells activates cytotoxic drugs used in cancer chemotherapy. The 2.1-Å crystal structure of rat liver quinone reductase reveals that the folding of a portion of each monomer is similar to that of flavodoxin, a bacterial FMN-containing protein. Two additional portions of the polypeptide chains are involved in dimerization and in formation of the two identical catalytic sites to which both monomers contribute. The crystallographic structures of two FAD-containing enzyme complexes (one containing NADP^+, the other containing duroquinone) suggest that direct hydride transfers from NAD(P)H to FAD and from FADH_2 to the quinone [which occupies the site vacated by NAD(P)H] provide a simple rationale for the obligatory two-electron reductions involving a ping-pong mechanism.

  4. A novel mechanism for momordin Ic-induced HepG2 apoptosis: involvement of PI3K- and MAPK-dependent PPARγ activation.

    Science.gov (United States)

    Wang, Jing; Yuan, Li; Xiao, Haifang; Wang, Chan; Xiao, Chunxia; Wang, Yutang; Liu, Xuebo

    2014-05-01

    Momordin Ic is a natural triterpenoid saponin found in various Chinese and Japanese natural medicines such as the fruit of Kochia scoparia (L.) Schrad. Momordin Ic has been previously demonstrated to induce HepG2 cell apoptosis in a ROS-mediated PI3K and MAPK pathway-dependent manner. In the present study, the underlying mechanisms of PI3K and MAPK pathway-mediated PPARγ, and PGC-1α co-regulator activation, as well as the effects of downstream proteins, COX-2 and FoxO4, on cell apoptosis were investigated. The results demonstrated that momordin Ic activated PPARγ and inhibited COX-2. PGC-1α and FoxO4 expressions were increased by the PI3K or MAPK pathways. Furthermore, PPARγ inhibition decreased p-p38 and FoxO4 expression, and restored COX-2 expression. ROS inhibition exerted little effect on PPARγ, COX-2 and FoxO4 expression but affected PGC-1α expression. These results revealed the involvement of PI3K and MAPK-dependent PPARγ activation in momordin Ic-induced apoptosis, providing more detailed information underlying the pro-apoptotic mechanism of momordin Ic in HepG2 cell apoptosis.

  5. Different molecular mechanisms involved in spontaneous and oxidative stress-induced mitochondrial fragmentation in tripeptidyl peptidase-1 (TPP-1)-deficient fibroblasts

    Science.gov (United States)

    Van Beersel, Guillaume; Tihon, Eliane; Demine, Stéphane; Hamer, Isabelle; Jadot, Michel; Arnould, Thierry

    2012-01-01

    NCLs (neuronal ceroid lipofuscinoses) form a group of eight inherited autosomal recessive diseases characterized by the intralysosomal accumulation of autofluorescent pigments, called ceroids. Recent data suggest that the pathogenesis of NCL is associated with the appearance of fragmented mitochondria with altered functions. However, even if an impairement in the autophagic pathway has often been evoked, the molecular mechanisms leading to mitochondrial fragmentation in response to a lysosomal dysfunction are still poorly understood. In this study, we show that fibroblasts that are deficient for the TPP-1 (tripeptidyl peptidase-1), a lysosomal hydrolase encoded by the gene mutated in the LINCL (late infantile NCL, CLN2 form) also exhibit a fragmented mitochondrial network. This morphological alteration is accompanied by an increase in the expression of the protein BNIP3 (Bcl2/adenovirus E1B 19 kDa interacting protein 3) as well as a decrease in the abundance of mitofusins 1 and 2, two proteins involved in mitochondrial fusion. Using RNAi (RNA interference) and quantitative analysis of the mitochondrial morphology, we show that the inhibition of BNIP3 expression does not result in an increase in the reticulation of the mitochondrial population in LINCL cells. However, this protein seems to play a key role in cell response to mitochondrial oxidative stress as it sensitizes mitochondria to antimycin A-induced fragmentation. To our knowledge, our results bring the first evidence of a mechanism that links TPP-1 deficiency and oxidative stress-induced changes in mitochondrial morphology. PMID:23249249

  6. Biochemical and molecular mechanisms involved in simultaneous phenol and Cr(VI) removal by Acinetobacter guillouiae SFC 500-1A.

    Science.gov (United States)

    Ontañon, Ornella M; González, Paola S; Agostini, Elizabeth

    2015-09-01

    Bioremediation has emerged as an environmental friendly strategy to deal with environmental pollution. Since the majority of polluted sites contain complex mixtures of inorganic and organic pollutants, it is important to find bacterial strains that can cope with multiple contaminants. In this work, a bacterial strain isolated from tannery sediments was identified as Acinetobacter guillouiae SFC 500-1A. This strain was able to simultaneously remove high phenol and Cr(VI) concentrations, and the mechanisms involved in such process were evaluated. The phenol biodegradation was catalized by a phenol-induced catechol 1,2-dioxygenase through an ortho-cleavage pathway. Also, NADH-dependent chromate reductase activity was measured in the cytosolic fraction. The ability of this strain to reduce Cr(VI) to Cr(III) was corroborated by detection of Cr(III) in cellular biomass after the removal process. While phenol did not affect significantly the chromate reductase activity, Cr(VI) was a major disruptor of catechol dioxygenase activity. Nevertheless, this activity was high even in presence of high Cr(VI) concentrations. Our results suggest the potential application of A. guillouiae SFC 500-1A for wastewaters treatment, and the obtained data provide the insights into the removal mechanisms, dynamics, and possible limitations of the bioremediation.

  7. Light effects on the multicellular magnetotactic prokaryote 'Candidatus Magnetoglobus multicellularis' are cancelled by radiofrequency fields: the involvement of radical pair mechanisms.

    Science.gov (United States)

    de Melo, Roger Duarte; Acosta-Avalos, Daniel

    2017-02-01

    'Candidatus Magnetoglobus multicellularis' is the most studied multicellular magnetotactic prokaryote. It presents a light-dependent photokinesis: green light decreases the translation velocity whereas red light increases it, in comparison to blue and white light. The present article shows that radio-frequency electromagnetic fields cancel the light effect on photokinesis. The frequency to cancel the light effect corresponds to the Zeeman resonance frequency (DC magnetic field of 4 Oe and radio-frequency of 11.5 MHz), indicating the involvement of a radical pair mechanism. An analysis of the orientation angle relative to the magnetic field direction shows that radio-frequency electromagnetic fields disturb the swimming orientation when the microorganisms are illuminated with red light. The analysis also shows that at low magnetic fields (1.6 Oe) the swimming orientation angles are well scattered around the magnetic field direction, showing that magnetotaxis is not efficiently in the swimming orientation to the geomagnetic field. The results do not support cryptochrome as being the responsible chromophore for the radical pair mechanism and perhaps two different chromophores are necessary to explain the radio-frequency effects.

  8. The accumulation mechanism of the hypoxia imaging probe “FMISO” by imaging mass spectrometry: possible involvement of low-molecular metabolites

    Science.gov (United States)

    Masaki, Yukiko; Shimizu, Yoichi; Yoshioka, Takeshi; Tanaka, Yukari; Nishijima, Ken-ichi; Zhao, Songji; Higashino, Kenichi; Sakamoto, Shingo; Numata, Yoshito; Yamaguchi, Yoshitaka; Tamaki, Nagara; Kuge, Yuji

    2015-01-01

    18F-fluoromisonidazole (FMISO) has been widely used as a hypoxia imaging probe for diagnostic positron emission tomography (PET). FMISO is believed to accumulate in hypoxic cells via covalent binding with macromolecules after reduction of its nitro group. However, its detailed accumulation mechanism remains unknown. Therefore, we investigated the chemical forms of FMISO and their distributions in tumours using imaging mass spectrometry (IMS), which visualises spatial distribution of chemical compositions based on molecular masses in tissue sections. Our radiochemical analysis revealed that most of the radioactivity in tumours existed as low-molecular-weight compounds with unknown chemical formulas, unlike observations made with conventional views, suggesting that the radioactivity distribution primarily reflected that of these unknown substances. The IMS analysis indicated that FMISO and its reductive metabolites were nonspecifically distributed in the tumour in patterns not corresponding to the radioactivity distribution. Our IMS search found an unknown low-molecular-weight metabolite whose distribution pattern corresponded to that of both the radioactivity and the hypoxia marker pimonidazole. This metabolite was identified as the glutathione conjugate of amino-FMISO. We showed that the glutathione conjugate of amino-FMISO is involved in FMISO accumulation in hypoxic tumour tissues, in addition to the conventional mechanism of FMISO covalent binding to macromolecules. PMID:26582591

  9. An Analysis of Government Involvement in Corporate Governance Mechanisms%公司治理的政府介入结构分析

    Institute of Scientific and Technical Information of China (English)

    向锐; 曹国华; 杨秀苔

    2001-01-01

    In this paper,the model has been constructed corresponding to the present situation of corporate governance mechanisms in China.With game theory,it is proved that the efficiency in corporate operation will be affected seriously by the governance mechanism in which the Government is involved excessively.We consider that the Government should withdraw State-owned property from industries as soon as possible and it should be a most urgent task at present to eliminate barriers of property rights in reformed state-owned enterprises.%针对当前我国股份公司治理机制的现状,本文构造了一个相应的模型,应用博弈论方法证明,政府过度介入公司治理将严重影响公司运行效率,认为国有资产应当尽快退出产业部门,以此消除国有企业改革的产权障碍,并且指出这应是当前最为急迫的一项任务。

  10. The rice OsNAC6 transcription factor orchestrates multiple molecular mechanisms involving root structural adaptions and nicotianamine biosynthesis for drought tolerance.

    Science.gov (United States)

    Lee, Dong-Keun; Chung, Pil Joong; Jeong, Jin Seo; Jang, Geupil; Bang, Seung Woon; Jung, Harin; Kim, Youn Shic; Ha, Sun-Hwa; Choi, Yang Do; Kim, Ju-Kon

    2016-11-28

    Drought has a serious impact on agriculture worldwide. A plant's ability to adapt to rhizosphere drought stress requires reprogramming of root growth and development. Although physiological studies have documented the root adaption for tolerance to the drought stress, underlying molecular mechanisms is still incomplete, which is essential for crop engineering. Here, we identified OsNAC6-mediated root structural adaptations, including increased root number and root diameter, which enhanced drought tolerance. Multiyear drought field tests demonstrated that the grain yield of OsNAC6 root-specific overexpressing transgenic rice lines was less affected by drought stress than were nontransgenic controls. Genome-wide analyses of loss- and gain-of-function mutants revealed that OsNAC6 up-regulates the expression of direct target genes involved in membrane modification, nicotianamine (NA) biosynthesis, glutathione relocation, 3'-phophoadenosine 5'-phosphosulphate accumulation and glycosylation, which represent multiple drought tolerance pathways. Moreover, overexpression of NICOTIANAMINE SYNTHASE genes, direct targets of OsNAC6, promoted the accumulation of the metal chelator NA and, consequently, drought tolerance. Collectively, OsNAC6 orchestrates novel molecular drought tolerance mechanisms and has potential for the biotechnological development of high-yielding crops under water-limiting conditions.

  11. Activated alveolar epithelial cells initiate fibrosis through autocrine and paracrine secretion of connective tissue growth factor.

    Science.gov (United States)

    Yang, Jibing; Velikoff, Miranda; Canalis, Ernesto; Horowitz, Jeffrey C; Kim, Kevin K

    2014-04-15

    Fibrogenesis involves a pathological accumulation of activated fibroblasts and extensive matrix remodeling. Profibrotic cytokines, such as TGF-β, stimulate fibroblasts to overexpress fibrotic matrix proteins and induce further expression of profibrotic cytokines, resulting in progressive fibrosis. Connective tissue growth factor (CTGF) is a profibrotic cytokine that is indicative of fibroblast activation. Epithelial cells are abundant in the normal lung, but their contribution to fibrogenesis remains poorly defined. Profibrotic cytokines may activate epithelial cells with protein expression and functions that overlap with the functions of active fibroblasts. We found that alveolar epithelial cells undergoing TGF-β-mediated mesenchymal transition in vitro were also capable of activating lung fibroblasts through production of CTGF. Alveolar epithelial cell expression of CTGF was dramatically reduced by inhibition of Rho signaling. CTGF reporter mice demonstrated increased CTGF promoter activity by lung epithelial cells acutely after bleomycin in vivo. Furthermore, mice with lung epithelial cell-specific deletion of CTGF had an attenuated fibrotic response to bleomycin. These studies provide direct evidence that epithelial cell activation initiates a cycle of fibrogenic effector cell activation during progressive fibrosis. Therapy targeted at epithelial cell production of CTGF offers a novel pathway for abrogating this progressive cycle and limiting tissue fibrosis.

  12. Hypertonic stress induces VEGF production in human colon cancer cell line Caco-2: inhibitory role of autocrine PGE₂.

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    Luciana B Gentile

    Full Text Available Vascular Endothelial Growth Factor (VEGF is a major regulator of angiogenesis. VEGF expression is up regulated in response to micro-environmental cues related to poor blood supply such as hypoxia. However, regulation of VEGF expression in cancer cells is not limited to the stress response due to increased volume of the tumor mass. Lipid mediators in particular arachidonic acid-derived prostaglandin (PGE₂ are regulators of VEGF expression and angiogenesis in colon cancer. In addition, increased osmolarity that is generated during colonic water absorption and feces consolidation seems to activate colon cancer cells and promote PGE₂ generation. Such physiological stimulation may provide signaling for cancer promotion. Here we investigated the effect of exposure to a hypertonic medium, to emulate colonic environment, on VEGF production by colon cancer cells. The role of concomitant PGE₂ generation and MAPK activation was addressed by specific pharmacological inhibition. Human colon cancer cell line Caco-2 exposed to a hypertonic environment responded with marked VEGF and PGE₂ production. VEGF production was inhibited by selective inhibitors of ERK 1/2 and p38 MAPK pathways. To address the regulatory role of PGE₂ on VEGF production, Caco-2 cells were treated with cPLA₂ (ATK and COX-2 (NS-398 inhibitors, that completely block PGE₂ generation. The Caco-2 cells were also treated with a non selective PGE₂ receptor antagonist. Each treatment significantly increased the hypertonic stress-induced VEGF production. Moreover, addition of PGE₂ or selective EP₂ receptor agonist to activated Caco-2 cells inhibited VEGF production. The autocrine inhibitory role for PGE₂ appears to be selective to hypertonic environment since VEGF production induced by exposure to CoCl₂ was decreased by inhibition of concomitant PGE₂ generation. Our results indicated that hypertonicity stimulates VEGF production in colon cancer cell lines. Also PGE

  13. Promotion of human early embryonic development and blastocyst outgrowth in vitro using autocrine/paracrine growth factors.

    Science.gov (United States)

    Kawamura, Kazuhiro; Chen, Yuan; Shu, Yimin; Cheng, Yuan; Qiao, Jie; Behr, Barry; Pera, Renee A Reijo; Hsueh, Aaron J W

    2012-01-01

    Studies using animal models demonstrated the importance of autocrine/paracrine factors secreted by preimplantation embryos and reproductive tracts for embryonic development and implantation. Although in vitro fertilization-embryo transfer (IVF-ET) is an established procedure, there is no evidence that present culture conditions are optimal for human early embryonic development. In this study, key polypeptide ligands known to be important for early embryonic development in animal models were tested for their ability to improve human early embryo development and blastocyst outgrowth in vitro. We confirmed the expression of key ligand/receptor pairs in cleavage embryos derived from discarded human tri-pronuclear zygotes and in human endometrium. Combined treatment with key embryonic growth factors (brain-derived neurotrophic factor, colony-stimulating factor, epidermal growth factor, granulocyte macrophage colony-stimulating factor, insulin-like growth factor-1, glial cell-line derived neurotrophic factor, and artemin) in serum-free media promoted >2.5-fold the development of tri-pronuclear zygotes to blastocysts. For normally fertilized embryos, day 3 surplus embryos cultured individually with the key growth factors showed >3-fold increases in the development of 6-8 cell stage embryos to blastocysts and >7-fold increase in the proportion of high quality blastocysts based on Gardner's criteria. Growth factor treatment also led to a 2-fold promotion of blastocyst outgrowth in vitro when day 7 surplus hatching blastocysts were used. When failed-to-be-fertilized oocytes were used to perform somatic cell nuclear transfer (SCNT) using fibroblasts as donor karyoplasts, inclusion of growth factors increased the progression of reconstructed SCNT embryos to >4-cell stage embryos. Growth factor supplementation of serum-free cultures could promote optimal early embryonic development and implantation in IVF-ET and SCNT procedures. This approach is valuable for infertility

  14. Promotion of human early embryonic development and blastocyst outgrowth in vitro using autocrine/paracrine growth factors.

    Directory of Open Access Journals (Sweden)

    Kazuhiro Kawamura

    Full Text Available Studies using animal models demonstrated the importance of autocrine/paracrine factors secreted by preimplantation embryos and reproductive tracts for embryonic development and implantation. Although in vitro fertilization-embryo transfer (IVF-ET is an established procedure, there is no evidence that present culture conditions are optimal for human early embryonic development. In this study, key polypeptide ligands known to be important for early embryonic development in animal models were tested for their ability to improve human early embryo development and blastocyst outgrowth in vitro. We confirmed the expression of key ligand/receptor pairs in cleavage embryos derived from discarded human tri-pronuclear zygotes and in human endometrium. Combined treatment with key embryonic growth factors (brain-derived neurotrophic factor, colony-stimulating factor, epidermal growth factor, granulocyte macrophage colony-stimulating factor, insulin-like growth factor-1, glial cell-line derived neurotrophic factor, and artemin in serum-free media promoted >2.5-fold the development of tri-pronuclear zygotes to blastocysts. For normally fertilized embryos, day 3 surplus embryos cultured individually with the key growth factors showed >3-fold increases in the development of 6-8 cell stage embryos to blastocysts and >7-fold increase in the proportion of high quality blastocysts based on Gardner's criteria. Growth factor treatment also led to a 2-fold promotion of blastocyst outgrowth in vitro when day 7 surplus hatching blastocysts were used. When failed-to-be-fertilized oocytes were used to perform somatic cell nuclear transfer (SCNT using fibroblasts as donor karyoplasts, inclusion of growth factors increased the progression of reconstructed SCNT embryos to >4-cell stage embryos. Growth factor supplementation of serum-free cultures could promote optimal early embryonic development and implantation in IVF-ET and SCNT procedures. This approach is valuable for

  15. Nelfinavir and other protease inhibitors in cancer: mechanisms involved in anticancer activity [v2; ref status: indexed, http://f1000r.es/536

    Directory of Open Access Journals (Sweden)

    Tomas Koltai

    2015-03-01

    Full Text Available Objective: To review the mechanisms of anti-cancer activity of nelfinavir and other protease inhibitors (PIs based on evidences reported in the published literature. Methods: We extensively reviewed the literature concerning nelfinavir (NFV as an off target anti-cancer drug and other PIs. A classification of PIs based on anti-cancer mode of action was proposed. Controversies regarding nelfinavir mode of action were also addressed. Conclusions: The two main mechanisms involved in anti-cancer activity are endoplasmic reticulum stress-unfolded protein response pathway and Akt inhibition. However there are many other effects, partially dependent and independent of those mentioned, that may be useful in cancer treatment, including MMP-9 and MMP-2 inhibition, down-regulation of CDK-2, VEGF, bFGF, NF-kB, STAT-3, HIF-1 alfa, IGF, EGFR, survivin, BCRP, androgen receptor, proteasome, fatty acid synthase (FAS, decrease in cellular ATP concentration and upregulation of TRAIL receptor DR5, Bax, increased radiosensitivity, and autophagy. The end result of all these effects is slower growth, decreased angiogenesis, decreased invasion and increased apoptosis, which means reduced proliferation and increased cancer cells death. PIs may be classified according to their anticancer activity at clinically achievable doses, in AKT inhibitors, ER stressors and Akt inhibitors/ER stressors. Beyond the phase I trials that have been recently completed, adequately powered and well-designed clinical trials are needed in the various cancer type settings, and specific trials where NFV is tested in association with other known anti-cancer pharmaceuticals should be sought, in order to find an appropriate place for NFV in cancer treatment. The analysis of controversies on the molecular mechanisms of NFV hints to the possibility that NFV works in a different way in tumor cells and in hepatocytes and adipocytes.

  16. Epithelial–mesenchymal transition during oncogenic transformation induced by hexavalent chromium involves reactive oxygen species-dependent mechanism in lung epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Song-Ze, E-mail: dingsongze@hotmail.com [Department of Internal Medicine, Henan Provincial People’s Hospital, Zhengzhou University, Wei-Wu Road, Zhengzhou, Henan 450000 (China); Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY 40536 (United States); Yang, Yu-Xiu; Li, Xiu-Ling [Department of Internal Medicine, Henan Provincial People’s Hospital, Zhengzhou University, Wei-Wu Road, Zhengzhou, Henan 450000 (China); Michelli-Rivera, Audrey [Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY 40536 (United States); Han, Shuang-Yin [Department of Internal Medicine, Henan Provincial People’s Hospital, Zhengzhou University, Wei-Wu Road, Zhengzhou, Henan 450000 (China); Wang, Lei; Pratheeshkumar, Poyil; Wang, Xin; Lu, Jian; Yin, Yuan-Qin; Budhraja, Amit; Hitron, Andrew J. [Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY 40536 (United States)

    2013-05-15

    Hexavalent chromium [Cr(VI)] is an important human carcinogen associated with pulmonary diseases and lung cancer. Exposure to Cr(VI) induces DNA damage, cell morphological change and malignant transformation in human lung epithelial cells. Despite extensive studies, the molecular mechanisms remain elusive, it is also not known if Cr(VI)-induced transformation might accompany with invasive properties to facilitate metastasis. We aimed to study Cr(VI)-induced epithelial–mesenchymal transition (EMT) and invasion during oncogenic transformation in lung epithelial cells. The results showed that Cr(VI) at low doses represses E-cadherin mRNA and protein expression, enhances mesenchymal marker vimentin expression and transforms the epithelial cell into fibroblastoid morphology. Cr(VI) also increases cell invasion and promotes colony formation. Further studies indicated that Cr(VI) uses multiple mechanisms to repress E-cadherin expression, including activation of E-cadherin repressors such as Slug, ZEB1, KLF8 and enhancement the binding of HDAC1 in E-cadherin gene promoter, but DNA methylation is not responsible for the loss of E-cadherin. Catalase reduces Cr(VI)-induced E-cadherin and vimentin protein expression, attenuates cell invasion in matrigel and colony formation on soft agar. These results demonstrate that exposure to a common human carcinogen, Cr(VI), induces EMT and invasion during oncogenic transformation in lung epithelial cells and implicate in cancer metastasis and prevention. - Graphical abstract: Epithelial–mesenchymal transition during oncogenic transformation induced by hexavalent chromium involves reactive oxygen species-dependent mechanisms in lung epithelial cells. - Highlights: • We study if Cr(VI) might induce EMT and invasion in epithelial cells. • Cr(VI) induces EMT by altering E-cadherin and vimentin expression. • It also increases cell invasion and promotes oncogenic transformation. • Catalase reduces Cr(VI)-induced EMT, invasion and

  17. 17 beta-estradiol-BSA conjugates and 17 beta-estradiol regulate growth plate chondrocytes by common membrane associated mechanisms involving PKC dependent and independent signal transduction.

    Science.gov (United States)

    Sylvia, V L; Walton, J; Lopez, D; Dean, D D; Boyan, B D; Schwartz, Z

    2001-01-01

    Nuclear receptors for 17 beta-estradiol (E(2)) are present in growth plate chondrocytes from both male and female rats and regulation of chondrocytes through these receptors has been studied for many years; however, recent studies indicate that an alternative pathway involving a membrane receptor may also be involved in the cell response. E(2) was found to directly affect the fluidity of chondrocyte membranes derived from female, but not male, rats. In addition, E(2) activates protein kinase C (PKC) in a nongenomic manner in female cells, and chelerythrine, a specific inhibitor of PKC, inhibits E(2)-dependent alkaline phosphatase activity and proteoglycan sulfation in these cells, indicating PKC is involved in the signal transduction mechanism. The aims of the present study were: (1) to examine the effect of a cell membrane-impermeable 17 beta-estradiol-bovine serum albumin conjugate (E(2)-BSA) on chondrocyte proliferation, differentiation, and matrix synthesis; (2) to determine the pathway that mediates the membrane effect of E(2)-BSA on PKC; and (3) to compare the action of E(2)-BSA to that of E(2). Confluent, fourth passage resting zone (RC) and growth zone (GC) chondrocytes from female rat costochondral cartilage were treated with 10(-9) to 10(-7) M E(2) or E(2)-BSA and changes in alkaline phosphatase specific activity, proteoglycan sulfation, and [(3)H]-thymidine incorporation measured. To examine the pathway of PKC activation, chondrocyte cultures were treated with E(2)-BSA in the presence or absence of GDP beta S (inhibitor of G-proteins), GTP gamma S (activator of G-proteins), U73122 or D609 (inhibitors of phospholipase C [PLC]), wortmannin (inhibitor of phospholipase D [PLD]) or LY294002 (inhibitor of phosphatidylinositol 3-kinase). E(2)-BSA mimicked the effects of E(2) on alkaline phosphatase specific activity and proteoglycan sulfation, causing dose-dependent increases in both RC and GC cell cultures. Both forms of estradiol inhibited [(3)H

  18. Heme oxygenase-1-derived carbon monoxide is an autocrine inhibitor of vascular smooth muscle cell growth.

    Science.gov (United States)

    Peyton, Kelly J; Reyna, Sylvia V; Chapman, Gary B; Ensenat, Diana; Liu, Xiao-ming; Wang, Hong; Schafer, Andrew I; Durante, William

    2002-06-15

    Vascular smooth muscle cells (SMCs) generate carbon monoxide (CO) via the catabolism of heme by the enzyme heme oxygenase (HO). In the present study, we found that serum stimulated a time- and concentration-dependent increase in the levels of HO-1 messenger RNA (mRNA) and protein in vascular SMCs. The induction of HO-1 expression by serum was inhibited by actinomycin D or cycloheximide. In addition, serum stimulated HO activity, as reflected by an increase in the concentration of bilirubin in the culture media. Treatment of vascular SMCs with serum stimulated DNA synthesis and this was potentiated by the HO inhibitors, zinc and tin protoporphyrin-IX as well as by the CO scavenger, hemoglobin. The iron chelator desferrioxamine had no effect on DNA synthesis. However, exposure of vascular SMCs to exogenous CO inhibited serum-stimulated SMC proliferation and the phosphorylation of retinoblastoma protein. In addition, CO arrested SMCs at the G(1)/S transition phase of the cell cycle and selectively blocked the serum-stimulated expression of cyclin A mRNA and protein without affecting the expression of cyclin D1 and E. CO also inhibited the serum-stimulated activation of cyclin A-associated kinase activity and cyclin-dependent kinase 2 activity. These results demonstrate that serum stimulates HO-1 gene expression and CO synthesis. Furthermore, they show that CO acts in a negative feedback fashion to inhibit vascular SMC growth by regulating specific components of the cell cycle machinery. The capacity of vascular mitogens to induce CO synthesis may provide a novel mechanism by which these agents modulate cell growth.

  19. The ectomycorrhizal fungus Paxillus involutus converts organic matter in plant litter using a trimmed brown-rot mechanism involving Fenton chemistry

    Science.gov (United States)

    Rineau, Francois; Roth, Doris; Shah, Firoz; Smits, Mark; Johansson, Tomas; Canbäck, Björn; Olsen, Peter Bjarke; Persson, Per; Grell, Morten Nedergaard; Lindquist, Erika; Grigoriev, Igor V; Lange, Lene; Tunlid, Anders

    2012-01-01

    Soils in boreal forests contain large stocks of carbon. Plants are the main source of this carbon through tissue residues and root exudates. A major part of the exudates are allocated to symbiotic ectomycorrhizal fungi. In return, the plant receives nutrients, in particular nitrogen from the mycorrhizal fungi. To capture the nitrogen, the fungi must at least partly disrupt the recalcitrant organic matter–protein complexes within which the nitrogen is embedded. This disruption process is poorly characterized. We used spectroscopic analyses and transcriptome profiling to examine the mechanism by which the ectomycorrhizal fungus Paxillus involutus degrades organic matter when acquiring nitrogen from plant litter. The fungus partially degraded polysaccharides and modified the structure of polyphenols. The observed chemical changes were consistent with a hydroxyl radical attack, involving Fenton chemistry similar to that of brown-rot fungi. The set of enzymes expressed by Pa. involutus during the degradation of the organic matter was similar to the set of enzymes involved in the oxidative degradation of wood by brown-rot fungi. However, Pa. involutus lacked transcripts encoding extracellular enzymes needed for metabolizing the released carbon. The saprotrophic activity has been reduced to a radical-based biodegradation system that can efficiently disrupt the organic matter–protein complexes and thereby mobilize the entrapped nutrients. We suggest that the released carbon then becomes available for further degradation and assimilation by commensal microbes, and that these activities have been lost in ectomycorrhizal fungi as an adaptation to symbiotic growth on host photosynthate. The interdependence of ectomycorrhizal symbionts and saprophytic microbes would provide a key link in the turnover of nutrients and carbon in forest ecosystems. PMID:22469289

  20. Mechanism of toxicity of the branched-chain fatty acid phytanic acid, a marker of Refsum disease, in astrocytes involves mitochondrial impairment.

    Science.gov (United States)

    Reiser, Georg; Schönfeld, Peter; Kahlert, Stefan

    2006-01-01

    Phytanic acid is a saturated branched-chain fatty acid, which is formed by bacterial degradation of chlorophyll in the intestinal tract of ruminants. The methyl group in beta-position prevents degradation of phytanic acid by the beta-oxidation pathway. Therefore, degradation of phytanic acid is initiated by alpha-oxidation in peroxisomes. The inherited peroxisomal disorder Refsum disease is characterised by accumulation of phytanic acid. Unusually high concentrations of phytanic acid can be found in the plasma of Refsum disease patients, who suffer from neurodegeneration and muscle dystrophy. Phytanic acid has been suggested to be causally involved in the clinical symptoms. To elucidate the pathogenic mechanism, we investigated the influence of phytanic acid in rat hippocampal astrocytes by monitoring the cytosolic Ca(2+) concentration, the mitochondrial membrane potential (Deltapsi(m)), the generation of reactive oxygen species as well as the cellular ATP level. In response to phytanic acid (100 microM) cytosolic Ca(2+) was quickly increased. The phytanic acid-evoked Ca(2+) response was transient and involved activation of intracellular Ca(2+) stores. In isolated rat brain mitochondria, phytanic acid dissipated Deltapsi(m) in a reversible and dose-dependent manner. Moreover, phytanic acid released cytochrome c from mitochondria. Depending on the mitochondrial activity state, phytanic acid either stimulated or inhibited the electron flux within the respiratory chain. In addition, phytanic acid induced substantial generation of reactive oxygen species in isolated mitochondria as well as in intact cells. Phytanic acid caused cell death of astrocytes within a few hours of exposure. In conclusion, we suggest that phytanic acid initiates astrocyte cell death by activating the mitochondrial route of apoptosis.

  1. Involvement of both Type I and Type II mechanisms in Gram-positive and Gram-negative bacteria photosensitization by a meso-substituted cationic porphyrin

    Energy Technology Data Exchange (ETDEWEB)

    Ergaieg, Karim; Seux, Rene [Laboratoire d' Etude et de Recherche en Environnement et Sante, National School of Public Health, Av. Pr. Leon Bernard, CS 74312, Rennes 35043 (France); Chevanne, Martine; Cillard, Josiane [Laboratoire de Biologie Cellulaire et Vegetale, UPRES 3891, UFR des Sciences Pharmaceutiques et Biologiques, University of Rennes 1, 2 Av. Pr. Leon Bernard, CS 34317, Rennes 35043 (France)

    2008-12-15

    A meso-substituted cationic porphyrin (TMPyP) showed a photocytotoxicity against Gram-positive and Gram-negative bacteria. In order to determine the mechanism involved in the phototoxicity of this photosensitizer, electron paramagnetic resonance (EPR) experiments with 2,2,6,6-tetramethyl-4-piperidone (TEMP), a specific probe for singlet oxygen, and the spin-trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) were carried out with illuminated TMPyP. An EPR signal characteristic of TEMP-singlet oxygen (TEMPO) adduct formation was observed, which could be ascribed to singlet oxygen ({sup 1}O{sub 2}) generated by TMPyP photosensitization. The signal for the DMPO spin adduct of superoxide anion (DMPO-OOH) was observed in DMSO solution but not in aqueous conditions. However, an EPR spectrum characteristic of the DMPO-hydroxyl radical spin adduct (DMPO-OH) was observed in aqueous conditions. The obtained results testify a primary hydroxyl radical ({sup .}OH) generation probably from superoxide anion (O{sub 2} {sup x} {sup -})via the Fenton reaction and/or via Haber-Weiss reaction. Gram-positive and Gram-negative bacteria inactivation by TMPyP photosensitization predominantly involved Type II reactions mediated by the formation of {sup 1}O{sub 2}, as demonstrated by the effect of quenchers for {sup 1}O{sub 2} and scavengers for {sup .}OH (sodium azide, thiourea, and dimethylsulphoxide). Participation of other active oxygen species cannot however be neglected since Type I reactions also had a significant effect, particularly for Gram-negative bacteria. For Gram-negative bacteria the photoinactivation rate was lower in the presence of superoxide dismutase, a specific O{sub 2} {sup x} {sup -} scavenger, and/or catalase, an enzyme which specifically eliminates H{sub 2}O{sub 2}, but was unchanged for Gram-positive bacteria. The generation of {sup 1}O{sub 2}, O{sub 2} {sup x} {sup -} and {sup .}OH by TMPyP photosensitization indicated that TMPyP maintained a photodynamic activity in

  2. Glucose stimulates neurotensin secretion from the rat small intestine by mechanisms involving SGLT1 and GLUT2, leading to cell depolarization and calcium influx.

    Science.gov (United States)

    Kuhre, Rune Ehrenreich; Bechmann, Louise Ellegaard; Wewer Albrechtsen, Nicolai Jacob; Hartmann, Bolette; Holst, Jens Juul

    2015-06-15

    Neurotensin (NT) is a neurohormone produced in the central nervous system and in the gut epithelium by the enteroendocrine N cell. NT may play a role in appetite regulation and may have potential in obesity treatment. Glucose ingestion stimulates NT secretion in healthy young humans, but the mechanisms involved are not well understood. Here, we show that rats express NT in the gut and that glucose gavage stimulates secretion similarly to oral glucose in humans. Therefore, we conducted experiments on isolated perfused rat small intestine with a view to characterize the cellular pathways of secretion. Luminal glucose (20% wt/vol) stimulated secretion but vascular glucose (5, 10, or 15 mmol/l) was without effect. The underlying mechanisms depend on membrane depolarization and calcium influx, since the voltage-gated calcium channel inhibitor nifedipine and the KATP channel opener diazoxide, which causes hyperpolarization, eliminated the response. Luminal inhibition of the sodium-glucose cotransporter 1 (SGLT1) (by phloridzin) eliminated glucose-stimulated release as well as secretion stimulated by luminal methyl-α-D-glucopyranoside (20% wt/vol), a metabolically inactive SGLT1 substrate, suggesting that glucose stimulates secretion by initial uptake by this transporter. However, secretion was also sensitive to GLUT2 inhibition (by phloretin) and blockage of oxidative phosphorylation (2-4-dinitrophenol). Direct KATP channel closure by sulfonylureas stimulated secretion. Therefore, glucose stimulates NT secretion by uptake through SGLT1 and GLUT2, both causing depolarization either as a consequence of sodium-coupled uptake (SGLT1) or by closure of KATP channels (GLUT2 and SGLT1) secondary to the ATP-generating metabolism of glucose.

  3. Silicon-mediated resistance of Arabidopsis against powdery mildew involves mechanisms other than the salicylic acid (SA)-dependent defence pathway.

    Science.gov (United States)

    Vivancos, Julien; Labbé, Caroline; Menzies, James G; Bélanger, Richard R

    2015-08-01

    On absorption by plants, silicon (Si) offers protection against many fungal pathogens, including powdery mildews. The mechanisms by which Si exerts its prophylactic role remain enigmatic, although a prevailing hypothesis suggests that Si positively influences priming. Attempts to decipher Si properties have been limited to plants able to absorb Si, which excludes the model plant Arabidopsis because it lacks Si influx transporters. In this work, we were able to engineer Arabidopsis plants with an Si transporter from wheat (TaLsi1) and to exploit mutants (pad4 and sid2) deficient in salicylic acid (SA)-dependent defence responses to study their phenotypic response and changes in defence expression against Golovinomyces cichoracearum (Gc) following Si treatment. Our results showed that TaLsi1 plants contained significantly more Si and were significantly more resistant to Gc infection than control plants when treated with Si, the first such demonstration in a plant transformed with a heterologous Si transporter. The resistant plants accumulated higher levels of SA and expressed higher levels of transcripts encoding defence genes, thus suggesting a role for Si in the process. However, TaLsi1 pad4 and TaLsi1 sid2 plants were also more resistant to Gc than were pad4 and sid2 plants following Si treatment. Analysis of the resistant phenotypes revealed a significantly reduced production of SA and expression of defence genes comparable with susceptible controls. These results indicate that Si contributes to Arabidopsis defence priming following pathogen infection, but highlight that Si will confer protection even when priming is altered. We conclude that Si-mediated protection involves mechanisms other than SA-dependent defence responses.

  4. A mechanism of male germ cell apoptosis induced by bisphenol-A and nonylphenol involving ADAM17 and p38 MAPK activation.

    Directory of Open Access Journals (Sweden)

    Paulina Urriola-Muñoz

    Full Text Available Germ cell apoptosis regulation is pivotal in order to maintain proper daily sperm production. Several reports have shown that endocrine disruptors such as Bisphenol-A (BPA and Nonylphenol (NP induce germ cell apoptosis along with a decrease in sperm production. Given their ubiquitous distribution in plastic products used by humans it is important to clarify their mechanism of action. TACE/ADAM17 is a widely distributed extracellular metalloprotease and participates in the physiological apoptosis of germ cells during spermatogenesis. The aims of this work were: 1 to determine whether BPA and NP induce ADAM17 activation; and 2 to study whether ADAM17 and/or ADAM10 are involved in germ cell apoptosis induced by BPA and NP in the pubertal rat testis. A single dose of BPA or NP (50 mg/kg induces germ cell apoptosis in 21-day-old male rats, which was prevented by a pharmacological inhibitor of ADAM17, but not by an inhibitor of ADAM10. In vitro, we showed that BPA and NP, at similar concentrations to those found in human samples, induce the shedding of exogenous and endogenous (TNF-α ADAM17 substrates in primary rat Sertoli cell cultures and TM4 cell line. In addition, pharmacological inhibitors of metalloproteases and genetic silencing of ADAM17 prevent the shedding induced in vitro by BPA and NP. Finally, we showed that in vivo BPA and NP induced early activation (phosphorylation of p38 MAPK and translocation of ADAM17 to the cell surface. Interestingly, the inhibition of p38 MAPK prevents germ cell apoptosis and translocation of ADAM17 to the cell surface. These results show for the first time that xenoestrogens can induce activation of ADAM17 at concentrations similar to those found in human samples, suggesting a mechanism by which they could imbalance para/juxtacrine cell-to-cell-communication and induce germ cell apoptosis.

  5. Ultra-deep pyrosequencing of partial surface protein genes from infectious Salmon Anaemia virus (ISAV suggest novel mechanisms involved in transition to virulence.

    Directory of Open Access Journals (Sweden)

    Turhan Markussen

    Full Text Available Uncultivable HPR0 strains of infectious salmon anaemia viruses (ISAVs infecting gills are non-virulent putative precursors of virulent ISAVs (vISAVs causing systemic disease in farmed Atlantic salmon (Salmo salar. The transition to virulence involves two molecular events, a deletion in the highly polymorphic region (HPR of the hemagglutinin-esterase (HE gene and a Q266→L266 substitution or insertion next to the putative cleavage site (R267 in the fusion protein (F. We have performed ultra-deep pyrosequencing (UDPS of these gene regions from healthy fish positive for HPR0 virus carrying full-length HPR sampled in a screening program, and a vISAV strain from an ISA outbreak at the same farming site three weeks later, and compared the mutant spectra. As the UDPS data shows the presence of both HE genotypes at both sampling times, and the outbreak strain was unlikely to be directly related to the HPR0 strain, this is the first report of a double infection with HPR0s and vISAVs. For F amplicon reads, mutation frequencies generating L266 codons in screening samples and Q266 codons in outbreak samples were not higher than at any random site. We suggest quasispecies heterogeneity as well as RNA structural properties are linked to transition to virulence. More specifically, a mechanism where selected single point mutations in the full-length HPR alter the RNA structure facilitating single- or sequential deletions in this region is proposed. The data provides stronger support for the deletion hypothesis, as opposed to recombination, as the responsible mechanism for generating the sequence deletions in HE.

  6. Ellagitannins of the fruit rind of pomegranate (Punica granatum antagonize in vitro the host inflammatory response mechanisms involved in the onset of malaria

    Directory of Open Access Journals (Sweden)

    Bhattacharya Deepak

    2010-07-01

    Full Text Available Abstract Background The sun-dried rind of the immature fruit of pomegranate (Punica granatum is presently used as a herbal formulation (OMARIA, Orissa Malaria Research Indigenous Attempt in Orissa, India, for the therapy and prophylaxis of malaria. The pathogenesis of cerebral malaria, a complication of the infection by Plasmodium falciparum, is an inflammatory cytokine-driven disease associated to an up-regulation and activity of metalloproteinase-9 and to the increase of TNF production. The in vitro anti-plasmodial activity of Punica granatum (Pg was recently described. The aim of the present study was to explore whether the anti-malarial effect of OMARIA could also be sustained via other mechanisms among those associated to the host immune response. Methods From the methanolic extract of the fruit rind, a fraction enriched in tannins (Pg-FET was prepared. MMP-9 secretion and expression were evaluated in THP-1 cells stimulated with haemozoin or TNF. The assays were conducted in the presence of the Pg-FET and its chemical constituents ellagic acid and punicalagin. The effect of urolithins, the ellagitannin metabolites formed by human intestinal microflora, was also investigated. Results Pg-FET and its constituents inhibited the secretion of MMP-9 induced by haemozoin or TNF. The effect occurred at transcriptional level since MMP-9 mRNA levels were lower in the presence of the tested compounds. Urolithins as well inhibited MMP-9 secretion and expression. Pg-FET and pure compounds also inhibited MMP-9 promoter activity and NF-kB-driven transcription. Conclusions The beneficial effect of the fruit rind of Punica granatum for the treatment of malarial disease may be attributed to the anti-parasitic activity and the inhibition of the pro-inflammatory mechanisms involved in the onset of cerebral malaria.

  7. Mechanisms involved in the modulation of astroglial resistance to oxidative stress induced by activated microglia: antioxidative systems, peroxide elimination, radical generation, lipid peroxidation.

    Science.gov (United States)

    Röhl, Claudia; Armbrust, Elisabeth; Herbst, Eva; Jess, Anne; Gülden, Michael; Maser, Edmund; Rimbach, Gerald; Bösch-Saadatmandi, Christine

    2010-05-01

    Microglia and astrocytes are the cellular key players in many neurological disorders associated with oxidative stress and neuroinflammation. Previously, we have shown that microglia activated by lipopolysaccharides (LPS) induce the expression of antioxidative enzymes in astrocytes and render them more resistant to hydrogen peroxide (H2O2). In this study, we examined the mechanisms involved with respect to the cellular action of different peroxides, the ability to detoxify peroxides, and the status of further antioxidative systems. Astrocytes were treated for 3 days with medium conditioned by purified quiescent (microglia-conditioned medium, MCM[-]) or LPS-activated (MCM[+]) microglia. MCM[+] reduced the cytotoxicity of the organic cumene hydroperoxide in addition to that of H2O2. Increased peroxide resistance was not accompanied by an improved ability of astrocytes to remove H2O2 or an increased expression/activity of peroxide eliminating antioxidative enzymes. Neither peroxide-induced radical generation nor lipid peroxidation were selectively affected in MCM[+] treated astrocytes. The glutathione content of peroxide resistant astrocytes, however, was increased and superoxide dismutase and heme oxygenase were found to be upregulated. These changes are likely to contribute to the higher peroxide resistance of MCM[+] treated astrocytes by improving their ability to detoxify reactive oxygen radicals and oxidation products. For C6 astroglioma cells a protective effect of microglia-derived factors could not be observed, underlining the difference of primary cells and cell lines concerning their mechanisms of oxidative stress resistance. Our results indicate the importance of microglial-astroglial cell interactions during neuroinflammatory processes.

  8. The Ras/Raf/MEK/Extracellular Signal-Regulated Kinase Pathway Induces Autocrine-Paracrine Growth Inhibition via the Leukemia Inhibitory Factor/JAK/STAT Pathway

    OpenAIRE

    Park, Jong-In; Strock, Christopher J.; Ball, Douglas W.; Nelkin, Barry D.

    2003-01-01

    Sustained activation of the Ras/Raf/MEK/extracellular signal-regulated kinase (ERK) pathway can lead to cell cycle arrest in many cell types. We have found, with human medullary thyroid cancer (MTC) cells, that activated Ras or c-Raf-1 can induce growth arrest by producing and secreting an autocrine-paracrine factor. This protein was purified from cell culture medium conditioned by Raf-activated MTC cells and was identified by mass spectrometry as leukemia inhibitory factor (LIF). LIF express...

  9. A phospho-dependent mechanism involving NCoR and KMT2D controls a permissive chromatin state at Notch target genes.

    Science.gov (United States)

    Oswald, Franz; Rodriguez, Patrick; Giaimo, Benedetto Daniele; Antonello, Zeus A; Mira, Laura; Mittler, Gerhard; Thiel, Verena N; Collins, Kelly J; Tabaja, Nassif; Cizelsky, Wiebke; Rothe, Melanie; Kühl, Susanne J; Kühl, Michael; Ferrante, Francesca; Hein, Kerstin; Kovall, Rhett A; Dominguez, Maria; Borggrefe, Tilman

    2016-06-02

    The transcriptional shift from repression to activation of target genes is crucial for the fidelity of Notch responses through incompletely understood mechanisms that likely involve chromatin-based control. To activate silenced genes, repressive chromatin marks are removed and active marks must be acquired. Histone H3 lysine-4 (H3K4) demethylases are key chromatin modifiers that establish the repressive chromatin state at Notch target genes. However, the counteracting histone methyltransferase required for the active chromatin state remained elusive. Here, we show that the RBP-J interacting factor SHARP is not only able to interact with the NCoR corepressor complex, but also with the H3K4 methyltransferase KMT2D coactivator complex. KMT2D and NCoR compete for the C-terminal SPOC-domain of SHARP. We reveal that the SPOC-domain exclusively binds to phosphorylated NCoR. The balance between NCoR and KMT2D binding is shifted upon mutating the phosphorylation sites of NCoR or upon inhibition of the NCoR kinase CK2β. Furthermore, we show that the homologs of SHARP and KMT2D in Drosophila also physically interact and control Notch-mediated functions in vivo Together, our findings reveal how signaling can fine-tune a committed chromatin state by phosphorylation of a pivotal chromatin-modifier.

  10. Advanced Fabrication of Chemically Bonded Graphene/TiO2 Continuous Fibers with Enhanced Broadband Photocatalytic Properties and Involved Mechanisms Exploration

    Science.gov (United States)

    Zhang, Qingzhe; Bao, Nan; Wang, Xinqiang; Hu, Xinde; Miao, Xinhan; Chaker, Mohamed; Ma, Dongling

    2016-12-01

    In this article, a novel route for the synthesis of graphene/TiO2 continuous fibers (GTF) using force-spinning combined with water vapor annealing method is reported for the first time. The morphology, structure and optical properties of the composite were fully characterized. With a single step of heat treatment process using steam at ambient conditions, we were able to initiate a series of chemical reactions, such as reduction of graphene oxide (GO), crystallization of TiO2, formation of C-Ti bond, and introduction of oxygen vacancies into TiO2. The incorporation of graphene in TiO2 fibers facilitated bandgap narrowing and improved photo-induced charge separation in the photocatalyst. As a result of synergistic effects, TiO2 fibers-2 wt% graphene (2%GTF) showed the highest photocatalytic activities in the degradation of X-3B under UV irradiation, superior to the benchmark photocatalyst P25. Under visible light irradiation, the same catalyst was about 4 times more efficient compared to pure TiO2 fibers (PTF). A detailed study of involved active species (in particular, ·, h+ and ·OH) unraveled the mechanism regarding photocatalysis.

  11. The involvement of noradrenergic mechanisms in the suppressive effects of diazepam on the hypothalamic-pituitary-adrenal axis activity in female rats

    Science.gov (United States)

    Švob Štrac, Dubravka; Muck-Šeler, Dorotea; Pivac, Nela

    2012-01-01

    Aim To elucidate the involvement of noradrenergic system in the mechanism by which diazepam suppresses basal hypothalamic-pituitary-adrenal (HPA) axis activity. Methods Plasma corticosterone and adrenocorticotropic hormone (ACTH) levels were determined in female rats treated with diazepam alone, as well as with diazepam in combination with clonidine (α2-adrenoreceptor agonist), yohimbine (α2-adrenoreceptor antagonist), alpha-methyl-p-tyrosine (α-MPT, an inhibitor of catecholamine synthesis), or reserpine (a catecholamine depleting drug) and yohimbine. Results Diazepam administered in a dose of 2.0 mg/kg suppressed basal HPA axis activity, ie, decreased plasma corticosterone and ACTH levels. Pretreatment with clonidine or yohimbine failed to affect basal plasma corticosterone and ACTH concentrations, but abolished diazepam-induced inhibition of the HPA axis activity. Pretreatment with α-MPT, or with a combination of reserpine and yohimbine, increased plasma corticosterone and ACTH levels and prevented diazepam-induced inhibition of the HPA axis activity. Conclusion The results suggest that α2-adrenoreceptors activity, as well as intact presynaptic noradrenergic function, are required for the suppressive effect of diazepam on the HPA axis activity. PMID:22661134

  12. Plants Possess a Cyclic Mitochondrial Metabolic Pathway similar to the Mammalian Metabolic Repair Mechanism Involving Malate Dehydrogenase and l-2-Hydroxyglutarate Dehydrogenase.

    Science.gov (United States)

    Hüdig, Meike; Maier, Alexander; Scherrers, Isabell; Seidel, Laura; Jansen, Erwin E W; Mettler-Altmann, Tabea; Engqvist, Martin K M; Maurino, Veronica G

    2015-09-01

    Enzymatic side reactions can give rise to the formation of wasteful and toxic products that are removed by metabolite repair pathways. In this work, we identify and characterize a mitochondrial metabolic repair mechanism in Arabidopsis thaliana involving malate dehydrogenase (mMDH) and l-2-hydroxyglutarate dehydrogenase (l-2HGDH). We analyze the kinetic properties of both A. thaliana mMDH isoforms, and show that they produce l-2-hydroxyglutarate (l-2HG) from 2-ketoglutarate (2-KG) at low rates in side reactions. We identify A. thaliana l-2HGDH as a mitochondrial FAD-containing oxidase that converts l-2HG back to 2-KG. Using loss-of-function mutants, we show that the electrons produced in the l-2HGDH reaction are transferred to the mitochondrial electron transport chain through the electron transfer protein (ETF). Thus, plants possess the biochemical components of an l-2HG metabolic repair system identical to that found in mammals. While deficiencies in the metabolism of l-2HG result in fatal disorders in mammals, accumulation of l-2HG in plants does not adversely affect their development under a range of tested conditions. However, orthologs of l-2HGDH are found in all examined genomes of viridiplantae, indicating that the repair reaction we identified makes an essential contribution to plant fitness in as yet unidentified conditions in the wild.

  13. Parental Involvement

    OpenAIRE

    Ezra S Simon

    2008-01-01

    This study was conducted in Ghana to investigate, (1) factors that predict parental involvement, (2) the relationship between parental home and school involvement and the educational achievement of adolescents, (3) the relationship between parental authoritativeness and the educational achievement of adolescent students, (4) parental involvement serving as a mediator between their authoritativeness and the educational achievement of the students, and (5) whether parental involvement decreases...

  14. Subcellular propagation of calcium waves in Müller glia does not require autocrine/paracrine purinergic signaling.

    Science.gov (United States)

    Phuong, Tam T T; Yarishkin, Oleg; Križaj, David

    2016-09-02

    The polarized morphology of radial glia allows them to functionally interconnect different layers of CNS tissues including the retina, cerebellum, and cortex. A likely mechanism involves propagation of transcellular Ca(2+) waves which were proposed to involve purinergic signaling. Because it is not known whether ATP release is required for astroglial Ca(2+) wave propagation we investigated this in mouse Müller cells, radial astroglia-like retinal cells in which in which waves can be induced and supported by Orai/TRPC1 (transient receptor potential isoform 1) channels. We found that depletion of endoplasmic reticulum (ER) stores triggers regenerative propagation of transcellular Ca(2+) waves that is independent of ATP release and activation of P2X and P2Y receptors. Both the amplitude and kinetics of transcellular, depletion-induced waves were resistant to non-selective purinergic P2 antagonists such as pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS). Thus, store-operated calcium entry (SOCE) is itself sufficient for the initiation and subcellular propagation of calcium waves in radial glia.

  15. Metaproteomics Identifies the Protein Machinery Involved in Metal and Radionuclide Reduction in Subsurface Microbiomes and Elucidates Mechanisms and U(VI) Reduction Immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Pfiffner, Susan M. [Univ. of Tennessee, Knoxville, TN (United States); Löffler, Frank [Univ. of Tennessee, Knoxville, TN (United States); Ritalahti, Kirsti [Univ. of Tennessee, Knoxville, TN (United States); Sayler, Gary [Univ. of Tennessee, Knoxville, TN (United States); Layton, Alice [Univ. of Tennessee, Knoxville, TN (United States); Hettich, Robert [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-08-31

    The overall goal for this funded project was to develop and exploit environmental metaproteomics tools to identify biomarkers for monitoring microbial activity affecting U speciation at U-contaminated sites, correlate metaproteomics profiles with geochemical parameters and U(VI) reduction activity (or lack thereof), elucidate mechanisms contributing to U(VI) reduction, and provide remediation project managers with additional information to make science-based site management decisions for achieving cleanup goals more efficiently. Although significant progress has been made in elucidating the microbiology contribution to metal and radionuclide reduction, the cellular components, pathway(s), and mechanisms involved in U trans-formation remain poorly understood. Recent advances in (meta)proteomics technology enable detailed studies of complex samples, including environmental samples, which differ between sites and even show considerable variability within the same site (e.g., the Oak Ridge IFRC site). Additionally, site-specific geochemical conditions affect microbial activity and function, suggesting generalized assessment and interpretations may not suffice. This research effort integrated current understanding of the microbiology and biochemistry of U(VI) reduction and capitalize on advances in proteomics technology made over the past few years. Field-related analyses used Oak Ridge IFRC field ground water samples from locations where slow-release substrate biostimulation has been implemented to accelerate in situ U(VI) reduction rates. Our overarching hypothesis was that the metabolic signature in environmental samples, as deciphered by the metaproteome measurements, would show a relationship with U(VI) reduction activity. Since metaproteomic and metagenomic characterizations were computationally challenging and time-consuming, we used a tiered approach that combines database mining, controlled laboratory studies, U(VI) reduction activity measurements, phylogenetic

  16. Mechanics

    CERN Document Server

    Hartog, J P Den

    1961-01-01

    First published over 40 years ago, this work has achieved the status of a classic among introductory texts on mechanics. Den Hartog is known for his lively, discursive and often witty presentations of all the fundamental material of both statics and dynamics (and considerable more advanced material) in new, original ways that provide students with insights into mechanical relationships that other books do not always succeed in conveying. On the other hand, the work is so replete with engineering applications and actual design problems that it is as valuable as a reference to the practicing e

  17. The nature of tryptophan radicals involved in the long-range electron transfer of lignin peroxidase and lignin peroxidase-like systems: Insights from quantum mechanical/molecular mechanics simulations.

    Science.gov (United States)

    Bernini, Caterina; Pogni, Rebecca; Basosi, Riccardo; Sinicropi, Adalgisa

    2012-05-01

    A catalytically active tryptophan radical has been demonstrated to be involved in the long-range electron transfer to the heme cofactor of lignin peroxidase (LiP) from Phanerochaete chrysosporium although no direct detection by EPR spectroscopy of the tryptophan radical intermediate has been reported to date. An engineering-based approach has been used to manipulate the microenvironment of the redox-active tryptophan site in LiP and Coprinus cinereus Peroxidase (CiP), allowing the direct evidence of the tryptophan radical species. In light of the newly available EPR experimental data, we performed a quantum mechanical/molecular mechanics computational study to characterize the tryptophan radicals in the above protein matrices as well as in pristine LiP. The nature of the tryptophan radicals is discussed together with the analysis of their environment with the aim of understanding the different behavior of pristine LiP in comparison with that of LiP and CiP variants.

  18. Autocrine Acetylcholine, Induced by IL-17A via NFκB and ERK1/2 Pathway Activation, Promotes MUC5AC and IL-8 Synthesis in Bronchial Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Angela Marina Montalbano

    2016-01-01

    Full Text Available IL-17A is overexpressed in the lung during acute neutrophilic inflammation. Acetylcholine (ACh increases IL-8 and Muc5AC production in airway epithelial cells. We aimed to characterize the involvement of nonneuronal components of cholinergic system on IL-8 and Muc5AC production in bronchial epithelial cells stimulated with IL-17A. Bronchial epithelial cells were stimulated with recombinant human IL-17A (rhIL-17A to evaluate the ChAT expression, the ACh binding and production, the IL-8 release, and the Muc5AC production. Furthermore, the effectiveness of PD098,059 (inhibitor of MAPKK activation, Bay11-7082 (inhibitor of IkBα phosphorylation, Hemicholinium-3 (HCh-3 (choline uptake blocker, and Tiotropium bromide (Spiriva® (anticholinergic drug was tested in our in vitro model. We showed that rhIL-17A increased the expression of ChAT, the levels of ACh binding and production, and the IL-8 and Muc5AC production in stimulated bronchial epithelial cells compared with untreated cells. The pretreatment of the cells with PD098,059 and Bay11-7082 decreased the ChAT expression and the ACh production/binding, while HCh-3 and Tiotropium decreased the IL-8 and Muc5AC synthesis in bronchial epithelial cells stimulated with rhIL-17A. IL-17A is involved in the IL-8 and Muc5AC production promoting, via NFκB and ERK1/2 pathway activation, the synthesis of ChAT, and the related activity of autocrine ACh in bronchial epithelial cells.

  19. Possible involvement of GABAergic mechanism in protective effect of melatonin against sleep deprivation-induced behaviour modification and oxidative damage in mice.

    Science.gov (United States)

    Kumar, Anil; Singh, Anant

    2009-08-01

    Sleep is an important physiological process responsible for the maintenance of physical, mental and emotional health of a living being. Sleep deprivation is considered risky for several pathological diseases such as anxiety and motor and cognitive dysfunctions. Sleep deprivation has recently been reported to cause oxidative damage. This study has been designed to explore the possible involvement of the GABAergic mechanism in protective effects of melatonin against 72-h sleep deprivation-induced behaviour modification and oxidative damage in mice. Mice were sleep-deprived for a period of 72 h using the grid over water suspended method. Animals were divided into groups of 6-8 animals each. Melatonin (5 and 10 mg/kg), flumazenil (0.5 mg/kg), picrotoxin (0.5 mg/kg) and muscimol (0.05 mg/kg) were administered for 5 days starting 2 days before 72-h sleep deprivation. Various behavioural tests (plus maze, zero maze, mirror chamber, actophotometer) and body weight assessment followed by oxidative stress parameters (malondialdehyde level, glutathione, catalase, nitrite and protein) were carried out. The 72-h sleep deprivation caused significant anxiety-like behaviour, weight loss, impaired locomotor activity and oxidative damage as compared with naïve (without sleep deprivation). Treatment with melatonin (5 mg/kg and 10 mg/kg, ip) significantly improved locomotor activity, weight loss and antianxiety effect as compared with control (sleep-deprived). Biochemically, melatonin treatment significantly restored reduced glutathione, catalase activity, attenuated lipid peroxidation and nitrite level as compared with control animals (72-h sleep-deprived). Flumazenil (0.5 mg/kg) and picrotoxin (0.5 mg/kg) pretreatments with a lower dose of melatonin (5 mg/kg) significantly antagonized the protective effect of melatonin. However, muscimol (0.05 mg/kg) pretreatment with melatonin (5 mg/kg, ip) potentiated the protective effect of melatonin which was significant as compared with their

  20. Prolonged propagation of rat neural stem cells relies on inhibiting autocrine/paracrine bone morphogenetic protein and platelet derived growth factor signals

    Institute of Scientific and Technical Information of China (English)

    Yirui Sun; Liangfu Zhou; Xing Wu; Hua Liu; Qiang Yuan; Ying Mao; Jin Hu

    2011-01-01

    Continuous expansion of rat neural stem cell lines has not been achieved due to proliferation arrest and spontaneous differentiation in vitro. In the current study, neural precursor cells derived from the subventricular zone of adult rats spontaneously underwent astroglial and oligodendroglial differentiation after limited propagation. This differentiation was largely induced by autocrine or paracrine bone morphogenetic protein and platelet derived growth factor signals. The results showed that, by inhibiting bone morphogenetic protein and platelet derived growth factor signals, adult rat neural precursor cells could be extensively cultured in vitro as tripotent stem cell lines. In addition to adult rat neural stem cells, we found that bone morphogenetic protein antagonists can promote the proliferation of human neural stem cells. Therefore, the present findings illustrated the role of autocrine or paracrine bone morphogenetic protein and platelet derived growth factor signaling in determining neural stem cell self-renewal and differentiation. By antagonizing both signals, the long-term propagation of rat neural stem cell lines can be achieved.

  1. Cytotoxic mechanisms of Zn{sup 2+} and Cd{sup 2+} involve Na{sup +}/H{sup +} exchanger (NHE) activation by ROS

    Energy Technology Data Exchange (ETDEWEB)

    Koutsogiannaki, Sophia [Laboratory of Animal Physiology, Zoology Department, School of Biology, Faculty of Science, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Evangelinos, Nikolaos [Laboratory of Animal Physiology, Zoology Department, School of Biology, Faculty of Science, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Koliakos, George [Department of Biological Chemistry, Medical School, Aristotle University of Thessaloniki, P.O. Box 17034, 54124 Thessaloniki (Greece); Kaloyianni, Martha [Laboratory of Animal Physiology, Zoology Department, School of Biology, Faculty of Science, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)]. E-mail: kaloyian@bio.auth.gr

    2006-07-20

    The signaling mechanism induced by cadmium (Cd) and zinc (Zn) in gill cells of Mytilus galloprovincialis was investigated. Both metals cause an increase in {center_dot}O{sub 2} {sup -} production, with Cd to be more potent (216 {+-} 15%) than Zn (150 {+-} 9.5%), in relation to control value (100%). The metals effect was reversed after incubation with the amiloride analogue, EIPA, a selective Na{sup +}/H{sup +} exchanger (NHE) inhibitor as well as in the presence of calphostin C, a protein kinase C (PKC) inhibitor. The heavy metals effect on {center_dot}O{sub 2} {sup -} production was mediated via the interaction of metal ions with {alpha}{sub 1}- and {beta}-adrenergic receptors, as shown after incubation with their respective agonists and antagonists. In addition, both metals caused an increase in intracellular pH (pHi) of gill cells. EIPA together with either metal significantly reduced the effect of each metal treatment on pHi. Incubation of gill cells with the oxidants rotenone, antimycin A and pyruvate caused a significant increase in pHi ({delta}pHi 0.830, 0.272 and 0.610, respectively), while in the presence of the anti-oxidant N-acetyl cysteine (NAC) a decrease in pHi ({delta}pHi -0.090) was measured, indicating that change in reactive oxygen species (ROS) production by heavy metals affects NHE activity. When rosiglitazone was incubated together with either heavy metal a decrease in O{sub 2} {sup -} production was observed. Our results show a key role of NHE in the signal transduction pathway induced by Zn and Cd in gill cells, with the involvement of ROS, PKC, adrenergic and PPAR-{gamma} receptors. In addition, differences between the two metals concerning NHE activation, O{sub 2} {sup -} production and interaction with adrenergic receptors were observed.

  2. Genome-wide transcriptomic and proteomic analyses of bollworm-infested developing cotton bolls revealed the genes and pathways involved in the insect pest defence mechanism.

    Science.gov (United States)

    Kumar, Saravanan; Kanakachari, Mogilicherla; Gurusamy, Dhandapani; Kumar, Krishan; Narayanasamy, Prabhakaran; Kethireddy Venkata, Padmalatha; Solanke, Amolkumar; Gamanagatti, Savita; Hiremath, Vamadevaiah; Katageri, Ishwarappa S; Leelavathi, Sadhu; Kumar, Polumetla Ananda; Reddy, Vanga Siva

    2016-06-01

    Cotton bollworm, Helicoverpa armigera, is a major insect pest that feeds on cotton bolls causing extensive damage leading to crop and productivity loss. In spite of such a major impact, cotton plant response to bollworm infection is yet to be witnessed. In this context, we have studied the genome-wide response of cotton bolls infested with bollworm using transcriptomic and proteomic approaches. Further, we have validated this data using semi-quantitative real-time PCR. Comparative analyses have revealed that 39% of the transcriptome and 35% of the proteome were differentially regulated during bollworm infestation. Around 36% of significantly regulated transcripts and 45% of differentially expressed proteins were found to be involved in signalling followed by redox regulation. Further analysis showed that defence-related stress hormones and their lipid precursors, transcription factors, signalling molecules, etc. were stimulated, whereas the growth-related counterparts were suppressed during bollworm infestation. Around 26% of the significantly up-regulated proteins were defence molecules, while >50% of the significantly down-regulated were related to photosynthesis and growth. Interestingly, the biosynthesis genes for synergistically regulated jasmonate, ethylene and suppressors of the antagonistic factor salicylate were found to be up-regulated, suggesting a choice among stress-responsive phytohormone regulation. Manual curation of the enzymes and TFs highlighted the components of retrograde signalling pathways. Our data suggest that a selective regulatory mechanism directs the reallocation of metabolic resources favouring defence over growth under bollworm infestation and these insights could be exploited to develop bollworm-resistant cotton varieties.

  3. Myeloperoxidase-derived hypochlorous acid promotes ox-LDL-induced senescence of endothelial cells through a mechanism involving β-catenin signaling in hyperlipidemia.

    Science.gov (United States)

    Liu, Wei-Qi; Zhang, Yin-Zhuang; Wu, Yan; Zhang, Jie-Jie; Li, Tin-Bo; Jiang, Tian; Xiong, Xiao-Ming; Luo, Xiu-Ju; Ma, Qi-Lin; Peng, Jun

    2015-11-27

    Myeloperoxidase (MPO)-derived product hypochlorous acid (HOCl) is able to induce cellular senescence and MPO is also expressed in endothelial cells besides the well-recognized immune cells. This study aims to clarify the association of endothelium-derived MPO with endothelial senescence in hyperlipidemia. The rats were fed with high-fat diet for 8 weeks to establish a hyperlipidemic model, which showed an increase in plasma lipids, endothelium-derived MPO expression, endothelial senescence and endothelial dysfunction concomitant with a reduction in glycogen synthase kinase 3 beta (GSK-3β) activity and phosphorylated β-catenin (p-β-catenin) level as well as an increase in β-catenin and p53 levels within the endothelium. Next, human umbilical vein endothelial cells (HUVECs) were incubated with oxidized low density lipoprotein (ox-LDL, 100 μg/ml) for 24 h to establish a senescent cell model in vitro. Consistent with the finding in vivo, ox-LDL-induced MPO expression and HUVECs senescence, accompanied by a decrease in GSK-3β activity and p-β-catenin level as well as an increase in HOCl content, β-catenin and p53 levels; these phenomena were attenuated by MPO inhibitor. Replacement of ox-LDL with HOCl could also induce HUVECs senescence and activate the β-catenin/p53 pathway. Based on these observations, we conclude that endothelium-derived MPO is upregulated in hyperlipidemic rats, which may contribute to the accelerated vascular endothelial senescence through a mechanism involving the β-catenin/p53 pathway.

  4. Study of the mechanisms involved in the laser superficial hardening process of metallic alloys; Estudo dos mecanismos envolvidos no processo de endurecimento superficial a laser de ligas metalicas

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Edmara Marques Rodrigues da

    2001-07-01

    The laser superficial hardening process of a ferrous alloy (gray cast iron) and of an aluminum-silicon alloy was investigated in this work. These metallic alloys are used in the automobile industry for manufacturing cylinders and pistons, respectively. By application of individual pulses and single tracks, the involved mechanisms during the processing were studied. Variables such as energy density, power density, temporal width, beam diameter on the sample surface, atmosphere of the processing region, overlapping and scanning velocity. The hardened surface was characterized by optical and scanning electronic microscopy, dispersive energy microanalysis, X-ray mapping, X-ray diffraction, and measurements of roughness and Vickers microhardness. Depending on the processing parameters, it is possible to obtain different microstructures. The affected area of gray cast iron, can be hardened by remelting or transformation hardening (total or partial) if the reached temperature is higher or not that of melting temperature. Laser treatment originated new structures such as retained austenite, martensite and, occasionally, eutectic of cellular dendritic structure. Aluminum-silicon alloy does not have phase transformation in solid state, it can be hardened only by remelting. The increase of hardness is a function of the precipitation hardening process, which makes the silicon particles smaller and more disperse in the matrix. Maximal values of microhardness (700-1000 HV) were reached with the laser treatment in gray cast iron samples. The initial microhardness is of 242 HV. For aluminum-silicon alloy, the laser remelting increases the initial microhardness of 128 HV to the range of 160-320 HV. The found results give a new perspective for using the CLA/IPEN's laser in the heat treatment area. Besides providing a higher absorptivity to the materials, compared with the CO{sub 2} laser, and optical fiber access, the superficial hardening with Nd:YAG laser, depending on the

  5. Mobilisation of endothelial progenitor cells: one of the possible mechanisms involved in the chronic administration of melatonin preventing erectile dysfunction in diabetic rats

    Institute of Scientific and Technical Information of China (English)

    Xue-Feng Qiu; Xiao-Xin Li; Yun Chen; Hao-Cheng Lin; Wen Yu; Run Wang; Yu-Tian Dai

    2012-01-01

    Diabetes-induced oxidative stress plays a critical role in the mobilisation of endothelial progenitor cells (EPCs) from the bone marrow to the circulation.This study was designed to explore the effects of chronic melatonin administration on the promotion of the mobilisation of EPCs and on the preservation of erectile function in type Ⅰ diabetic rats.Melatonin was administered to streptozotocin-induced type Ⅰdiabetic rats.EPCs levels were determined using flow cytometry,Oxidative stress in the bone marrow was indicated by the levels of superoxide dismutase and malondialdehyde.Erectile function was evaluated by measuring the intracavemous pressure during an electrostimulation of the cavernous nerve.The density of the endothelium and the proportions of smooth muscle and collagen in the corpus cavernosum were determined by immunohistochemistry.The administration of melatonin increased the superoxide dismutase level and decreased the malondiaidehyde level in the bone marrow,This effect was accompanied by an increased level of circulating EPCs in the diabetic rats.The intracavernous pressure to mean arterial pressure ratio of the rats in the treatment group was significantly greater,compared with diabetic control rats.The histological analysis demonstrated an increase in the endothelial density of the corpus cavernosum after the administration of melatonin.However,melatonin treatment did not change the proportions of smooth muscle and collagen in the corpus cavernosum of diabetic rats.Chronic administration of melatonin has a beneficial effect on preventing erectile dysfunction (ED) in type Ⅰ diabetic rats.Promoting the mobilisation of EPCs is one of the possible mechanisms involved in the improvement of ED.

  6. Fucoidan extract induces apoptosis in MCF-7 cells via a mechanism involving the ROS-dependent JNK activation and mitochondria-mediated pathways.

    Directory of Open Access Journals (Sweden)

    Zhongyuan Zhang

    Full Text Available BACKGROUND: Fucoidan extract (FE, an enzymatically digested compound with a low molecular weight, is extracted from brown seaweed. As a natural compound with various actions, FE is attractive, especially in Asian countries, for improving the therapeutic efficacy and safety of cancer treatment. The present study was carried out to investigate the anti-tumor properties of FE in human carcinoma cells and further examine the underlying mechanisms of its activities. METHODOLOGY/PRINCIPAL FINDING: FE inhibits the growth of MCF-7, MDA-MB-231, HeLa, and HT1080 cells. FE-mediated apoptosis in MCF-7 cancer cells is accompanied by DNA fragmentation, nuclear condensation, and phosphatidylserine exposure. FE induces mitochondrial membrane permeabilization (MMP through loss of mitochondrial membrane potential (ΔΨm and regulation of the expression of Bcl-2 family members. Release of apoptosis-inducing factor (AIF and cytochrome c precedes MMP. AIF release causes DNA fragmentation, the final stage of apoptosis, via a caspase-independent mitochondrial pathway. Additionally, FE was found to induce phosphorylation of c-Jun N-terminal kinase (JNK, p38, and extracellular signal-regulated kinase (ERK 1/2, and apoptosis was found to be attenuated by inhibition of JNK. Furthermore, FE-mediated apoptosis was found to involve the generation of reactive oxygen species (ROS, which are responsible for the decrease of ΔΨm and phosphorylation of JNK, p38, and ERK1/2 kinases. CONCLUSIONS/SIGNIFICANCE: These data suggest that FE activates a caspase-independent apoptotic pathway in MCF-7 cancer cells through activation of ROS-mediated MAP kinases and regulation of the Bcl-2 family protein-mediated mitochondrial pathway. They also provide evidence that FE deserves further investigation as a natural anticancer and cancer preventive agent.

  7. Mechanisms involved in protection afforded by L-arginine in ibuprofen-induced gastric damage: role of nitric oxide and prostaglandins.

    Science.gov (United States)

    Jiménez, Dolores; Martin, M José; Pozo, David; Alarcón, Catalina; Esteban, José; Bruseghini, Leo; Esteras, Antonio; Motilva, Virginia

    2002-01-01

    L-Arginine (L-arg) exhibits multiple biological properties and plays an important role in the regulation of different functions in pathological conditions. Many of these effects could be achieved on this amino acid serving as a substrate for the enzyme nitric oxide synthase (NOS). At the gastrointestinal level, recent reports revealed its protective activities involving a hyperemic response increasing the gastric blood flow. The aim of this study was to characterize the relationship between NOS activity/expression and prostaglandin changes (PGs) in rats gastric mucosa, with L-arg associated resistance to the nonsteroidal anti-inflammatory drug (NSAID) ibuprofen (IBP). The protective effect of oral L-arg (100 mg/kg body wt), administerred together with IBP (100 mg/kg body wt, per os), was evident enough 90 min after drug administration, although a significant protection persisted for more than 6 hr. Pretreatment with N(G)-nitro-L-arginine (L-NNA) (40 mg/kg body wt, intraperitoneally), a competitive inhibitor of constitutive NOS, partly altered the protection afforded by the amino acid. In contrast, no changes could be observed after inducible NOS inhibition [aminoguanidine (AG) 50 mg/Kg body wt, intraperitoneally). L-arg, plus IBP, produced a significant increase of the cyclic GMP (cGMP) response in tissue samples from rat stomach, 90 min and 6 h after drug administration. iNOS activity and mRNA expression were higher in IBP-treated rats, and no differences were observed in inducible responses in the L-arg plus IBP group. No variations in the cNOS activity and expression were found among the different groups of animals assayed. The measurement of mucosal PGE2 content confirmed that biosynthesis of the eicosanoid is maintained by L-arg for over 90 min after IBP, while a total inhibition was observed 6 hr later. The mechanisms of the L-arg protective effect on the damaged induced by IBP could be explained by the different period after drug administration. The early

  8. In vitro screening of major neurotransmitter systems possibly involved in the mechanism of action of antibodies to S100 protein in released-active form

    Directory of Open Access Journals (Sweden)

    Gorbunov EA

    2015-11-01

    Full Text Available Evgeniy A Gorbunov, Irina A Ertuzun, Evgeniya V Kachaeva, Sergey A Tarasov, Oleg I EpsteinOOO “NPF “MATERIA MEDICA HOLDING”, Moscow, Russian FederationAbstract: Experimentally and clinically, it was shown that released-active form of antibodies to S100 protein (RAF of Abs to S100 exerts a wide range of pharmacological activities: anxiolytic, antiasthenic, antiaggressive, stress-protective, antihypoxic, antiischemic, neuroprotective, and nootropic. The purpose of this study was to determine the influence of RAF of Abs to S100 on major neurotransmitter systems (serotoninergic, GABAergic, dopaminergic, and on sigma receptors as well which are possibly involved in its mechanism of pharmacological activity. Radioligand binding assays were used for assessment of the drug influence on ligand–receptor interaction. [35S]GTPγS binding assay, cyclic adenosine monophosphate HTRF™, cellular dielectric spectroscopy assays, and assays based on measurement of intracellular concentration of Ca2+ ions were used for assessment of agonist or antagonist properties of the drug toward receptors. RAF of Abs to S100 increased radioligand binding to 5-HT1F, 5-HT2B, 5-HT2Cedited, 5-HT3, and to D3 receptors by 142.0%, 131.9%, 149.3%, 120.7%, and 126.3%, respectively. Also, the drug significantly inhibited specific binding of radioligands to GABAB1A/B2 receptors by 25.8%, and to both native and recombinant human sigma1 receptors by 75.3% and 40.32%, respectively. In the functional assays, it was shown that the drug exerted antagonism at 5-HT1B, D3, and GABAB1A/B2 receptors inhibiting agonist-induced responses by 23.24%, 32.76%, and 30.2%, respectively. On the contrary, the drug exerted an agonist effect at 5-HT1A receptors enhancing receptor functional activity by 28.0%. The pharmacological profiling of RAF of Abs to S100 among 27 receptor provides evidence for drug-related modification of major neurotransmitter systems.Keywords: dopamine agent, released

  9. Epigenetic mechanisms involved in differential MDR1 mRNA expression between gastric and colon cancer cell lines and rationales for clinical chemotherapy

    Directory of Open Access Journals (Sweden)

    Kim Kyung-Jong

    2008-08-01

    Full Text Available Abstract Background The membrane transporters such as P-glycoprotein (Pgp, the MDR1 gene product, are one of causes of treatment failure in cancer patients. In this study, the epigenetic mechanisms involved in differential MDR1 mRNA expression were compared between 10 gastric and 9 colon cancer cell lines. Methods The MDR1 mRNA levels were determined using PCR and real-time PCR assays after reverse transcription. Cytotoxicity was performed using the MTT assay. Methylation status was explored by quantification PCR-based methylation and bisulfite DNA sequencing analyses. Results The MDR1 mRNA levels obtained by 35 cycles of RT-PCR in gastric cancer cells were just comparable to those obtained by 22 cycles of RT-PCR in colon cancer cells. Real-time RT-PCR analysis revealed that MDR1 mRNA was not detected in the 10 gastric cancer cell lines but variable MDR1 mRNA levels in 7 of 9 colon cancer cell lines except the SNU-C5 and HT-29 cells. MTT assay showed that Pgp inhibitors such as cyclosporine A, verapamil and PSC833 sensitized Colo320HSR (colon, highest MDR1 expression but not SNU-668 (gastric, highest and SNU-C5 (gastric, no expression to paclitaxel. Quantification PCR-based methylation analysis revealed that 90% of gastric cancer cells, and 33% of colon cancer cells were methylated, which were completely matched with the results obtained by bisulfite DNA sequencing analysis. 5-aza-2'-deoxcytidine (5AC, a DNA methyltransferase inhibitor increased the MDR1 mRNA levels in 60% of gastric cells, and in 11% of colon cancer cells. Trichostatin A (TSA, histone deacetylase inhibitor increased the MDR1 mRNA levels in 70% of gastric cancer cells and 55% of colon cancer cells. The combined treatment of 5AC with TSA increased the MDR1 mRNA levels additively in 20% of gastric cancer cells, but synergistically in 40% of gastric and 11% of colon cancer cells. Conclusion These results indicate that the MDR1 mRNA levels in gastric cancer cells are significantly

  10. Co-expression of epidermal growth factor-receptor and c-erb B-2 proto-oncogene product in human salivary-gland adenocarcinoma cell line HSG and the implications for HSG cell autocrine growth.

    Science.gov (United States)

    Kyakumoto, S; Kurokawa, R; Hoshino, M; Ota, M

    1994-07-01

    The autonomous proliferation of HSG cells is mediated by an autocrine growth factor, a 46K epidermal growth factor (EGF)-like molecule. The receptor for this molecule was investigated. Immunoprecipitation and immunoblotting revealed the expression of two possible receptor molecules, EGF-R and p185erbB-2, in HSG cells. Northern blotting also revealed the co-expression of 5.6-kb EGF-R mRNA and 4.6-kb c-erb B-2 mRNA. When the purified EGF-like molecule was added to the cultures, EGF-R but not p185erbB-2 was autophosphorylated. These results suggest that, although both EGF-R and p185erbB-2 are co-expressed in HSG cells, the EGF-R is the genuine receptor for the EGF-like molecule. However, there is a possibility that p185erB-2 is involved in the signal transduction system. This possibility was examined by using specific antibodies to human EGF-R (hEGF-R), p185erbB-2, and EGF to inhibit the functions of these molecules. Addition of these three antibodies to the cultures inhibited the growth of HSG cells. The antibodies to EGF-R and p185erbB-2 also caused morphological changes such as disturbances of the plasma membrane, and some cell death. Surprisingly, the effect of the anti-p185erbB-2 antibody on growth inhibition and morphology was stronger than that of the anti-hEGF-R antibody. Thus, p185erB-2 expressed in HSG cells has an important function in the signal transduction of HSG cell growth.

  11. Metaproteomics Identifies the Protein Machinery Involved in Metal and Radionuclide Reduction in Subsurface Microbiomes and Elucidates Mechanisms and U(VI) Reduction Immobilization

    Energy Technology Data Exchange (ETDEWEB)

    Pfiffner, Susan M. [Univ. of Tennessee, Knoxville, TN (United States); Löffler, Frank [Univ. of Tennessee, Knoxville, TN (United States); Ritalahti, Kirsti [Univ. of Tennessee, Knoxville, TN (United States); Sayler, Gary [Univ. of Tennessee, Knoxville, TN (United States); Layton, Alice [Univ. of Tennessee, Knoxville, TN (United States); Hettich, Robert [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-08-31

    The overall goal for this funded project was to develop and exploit environmental metaproteomics tools to identify biomarkers for monitoring microbial activity affecting U speciation at U-contaminated sites, correlate metaproteomics profiles with geochemical parameters and U(VI) reduction activity (or lack thereof), elucidate mechanisms contributing to U(VI) reduction, and provide remediation project managers with additional information to make science-based site management decisions for achieving cleanup goals more efficiently. Although significant progress has been made in elucidating the microbiology contribution to metal and radionuclide reduction, the cellular components, pathway(s), and mechanisms involved in U trans-formation remain poorly understood. Recent advances in (meta)proteomics technology enable detailed studies of complex samples, including environmental samples, which differ between sites and even show considerable variability within the same site (e.g., the Oak Ridge IFRC site). Additionally, site-specific geochemical conditions affect microbial activity and function, suggesting generalized assessment and interpretations may not suffice. This research effort integrated current understanding of the microbiology and biochemistry of U(VI) reduction and capitalize on advances in proteomics technology made over the past few years. Field-related analyses used Oak Ridge IFRC field ground water samples from locations where slow-release substrate biostimulation has been implemented to accelerate in situ U(VI) reduction rates. Our overarching hypothesis was that the metabolic signature in environmental samples, as deciphered by the metaproteome measurements, would show a relationship with U(VI) reduction activity. Since metaproteomic and metagenomic characterizations were computationally challenging and time-consuming, we used a tiered approach that combines database mining, controlled laboratory studies, U(VI) reduction activity measurements, phylogenetic

  12. A review on the mechanisms of blood-flow restriction resistance training-induced muscle hypertrophy.

    Science.gov (United States)

    Pearson, Stephen John; Hussain, Syed Robiul

    2015-02-01

    It has traditionally been believed that resistance training can only induce muscle growth when the exercise intensity is greater than 65% of the 1-repetition maximum (RM). However, more recently, the use of low-intensity resistance exercise with blood-flow restriction (BFR) has challenged this theory and consistently shown that hypertrophic adaptations can be induced with much lower exercise intensities (training being demonstrated by numerous studies, the underlying mechanisms responsible for such effects are not well defined. Metabolic stress has been suggested to be a primary factor responsible, and this is theorised to activate numerous other mechanisms, all of which are thought to induce muscle growth via autocrine and/or paracrine actions. However, it is noteworthy that some of these mechanisms do not appear to be mediated to any great extent by metabolic stress but rather by mechanical tension (another primary factor of muscle hypertrophy). Given that the level of mechanical tension is typically low with BFR resistance exercise (adaptations reported with BFR resistance training. However, despite the low level of mechanical tension, it is plausible that the effects induced by the primary factors (mechanical tension and metabolic stress) are, in fact, additive, which ultimately contributes to the adaptations seen with BFR resistance training. Exercise-induced mechanical tension and metabolic stress are theorised to signal a number of mechanisms for the induction of muscle growth, including increased fast-twitch fibre recruitment, mechanotransduction, muscle damage, systemic and localised hormone production, cell swelling, and the production of reactive oxygen species and its variants, including nitric oxide and heat shock proteins. However, the relative extent to which these specific mechanisms are induced by the primary factors with BFR resistance exercise, as well as their magnitude of involvement in BFR resistance training-induced muscle hypertrophy

  13. Effects of betaine on performance and body composition: a review of recent findings and potential mechanisms.

    Science.gov (United States)

    Cholewa, Jason M; Guimarães-Ferreira, Lucas; Zanchi, Nelo Eidy

    2014-08-01

    Betaine is a methyl derivative of glycine first isolated from sugar beets. Betaine consumed from food sources and through dietary supplements presents similar bioavailability and is metabolized to di-methylglycine and sarcosine in the liver. The ergogenic and clinical effects of betaine have been investigated with doses ranging from 500 to 9,000 mg/day. Some studies using animal models and human subjects suggest that betaine supplementation could promote adiposity reductions and/or lean mass gains. Moreover, previous investigations report positive effects of betaine on sports performance in both endurance- and resistance-type exercise, despite some conflicting results. The mechanisms underlying these effects are poorly understood, but could involve the stimulation of lipolysis and inhibition of lipogenesis via gene expression and subsequent activity of lipolytic-/lipogenic-related proteins, stimulation of autocrine/endocrine IGF-1 release and insulin receptor signaling pathways, stimulation of growth hormone secretion, increased creatine synthesis, increases in protein synthesis via intracellular hyper-hydration, as well as exerting psychological effects such as attenuating sensations of fatigue. However, the exact mechanisms behind betaine action and the long-term effects of supplementation on humans remain to be elucidated. This review aims to describe evidence for the use of betaine as an ergogenic and esthetic aid, and discuss the potential mechanisms underlying these effects.

  14. Mechanics

    CERN Document Server

    Chester, W

    1979-01-01

    When I began to write this book, I originally had in mind the needs of university students in their first year. May aim was to keep the mathematics simple. No advanced techniques are used and there are no complicated applications. The emphasis is on an understanding of the basic ideas and problems which require expertise but do not contribute to this understanding are not discussed. How­ ever, the presentation is more sophisticated than might be considered appropri­ ate for someone with no previous knowledge of the subject so that, although it is developed from the beginning, some previous acquaintance with the elements of the subject would be an advantage. In addition, some familiarity with element­ ary calculus is assumed but not with the elementary theory of differential equations, although knowledge of the latter would again be an advantage. It is my opinion that mechanics is best introduced through the motion of a particle, with rigid body problems left until the subject is more fully developed. Howev...

  15. IL-35 promotes pancreas cancer growth through enhancement of proliferation and inhibition of apoptosis: evidence for a role as an autocrine growth factor.

    Science.gov (United States)

    Nicholl, Michael B; Ledgewood, Chelsea L; Chen, Xuhui; Bai, Qian; Qin, Chenglu; Cook, Kathryn M; Herrick, Elizabeth J; Diaz-Arias, Alberto; Moore, Bradley J; Fang, Yujiang

    2014-12-01

    Interleukin-35 (IL-35), an IL-12 cytokine family member, mediates the immune inhibitory function of regulatory T cells (Treg). We assayed the presence of IL-35 in paraffin-embedded human pancreas cancer (PCAN) and unexpectedly found IL-35 was expressed mainly by epithelial derived PCAN cells, but not by Treg. We further examined the expression and effect of exogenous IL-35 in human PCAN cell lines and found IL-35 promoted growth and inhibited apoptosis in PCAN cell lines. IL-35 induced proliferation correlated with an increase in cyclin B, cyclin D, cdk2, and cdk4 and a decrease in p27 expression, while inhibition of apoptosis was associated with an increase in Bcl-2 and a decrease in TRAILR1. We conclude IL-35 is produced by PCAN in vivo and promotes PCAN cell line growth in vitro. These results might indicate an important new role for IL-35 as an autocrine growth factor in PCAN growth.

  16. Regulation of Prostate Development and Benign Prostatic Hyperplasia by Autocrine Cholinergic Signaling via Maintaining the Epithelial Progenitor Cells in Proliferating Status

    Directory of Open Access Journals (Sweden)

    Naitao Wang

    2016-05-01

    Full Text Available Regulation of prostate epithelial progenitor cells is important in prostate development and prostate diseases. Our previous study demonstrated a function of autocrine cholinergic signaling (ACS in promoting prostate cancer growth and castration resistance. However, whether or not such ACS also plays a role in prostate development is unknown. Here, we report that ACS promoted the proliferation and inhibited the differentiation of prostate epithelial progenitor cells in organotypic cultures. These results were confirmed by ex vivo lineage tracing assays and in vivo renal capsule recombination assays. Moreover, we found that M3 cholinergic receptor (CHRM3 was upregulated in a large subset of benign prostatic hyperplasia (BPH tissues compared with normal tissues. Activation of CHRM3 also promoted the proliferation of BPH cells. Together, our findings identify a role of ACS in maintaining prostate epithelial progenitor cells in the proliferating state, and blockade of ACS may have clinical implications for the management of BPH.

  17. Community involvement

    Directory of Open Access Journals (Sweden)

    Editorial Office

    1979-09-01

    Full Text Available Community involvement is the main theme of Health Year. Governments have a responsibility for the health of their people, and in this country under the present 3-tier system of government, the responsibility for the rendering of health services is divided between central, provincial and local government. However, under our democratic system, all people have the right to, and it is indeed their duty, to participate individually and collectively in the planning and implementation of services to meet their health needs. Ultimately, through involvement of individuals, families and communities, greater self-reliance is achieved leading to greater responsibility being assumed by people for their own health.

  18. Platelet-derived sphingosine-1-phosphate and inflammation: from basic mechanisms to clinical implications.

    Science.gov (United States)

    Vito, Clara Di; Hadi, Loubna Abdel; Navone, Stefania Elena; Marfia, Giovanni; Campanella, Rolando; Mancuso, Maria Elisa; Riboni, Laura

    2016-07-01

    Beyond key functions in hemostasis and thrombosis, platelets are recognized as key players of inflammation, an underlying feature of a variety of diseases. In this regard, platelets act as a circulating source of several pro- and anti-inflammatory molecules, which are secreted from their intracellular stores upon activation. Among them, mounting evidence highlights a crucial role of sphingosine-1-phosphate (S1P), a multifunctional sphingoid mediator. S1P-induced pleiotropic effects include those crucial in inflammatory processes, such as the maintenance of the endothelial barrier integrity, and leukocyte activation and recruitment at the injured site. This review outlines the peculiar features and molecular mechanisms that allow platelets for acting as a unique factory that produces and stores S1P in large quantities. A particular emphasis is placed on the autocrine and paracrine roles of S1P derived from the "inflamed" platelets, highlighting the role of its cross-talk with endothelial and blood cells involved in inflammation, and the mechanisms of its contribution to the development and progression of inflammatory diseases. Finally, potential clinical implications of platelet-derived S1P as diagnostic tool of inflammatory severity, and as therapeutic target in inflammation are discussed.

  19. Capsaicin mimics mechanical load-induced intracellular signaling events: involvement of TRPV1-mediated calcium signaling in induction of skeletal muscle hypertrophy.

    Science.gov (United States)

    Ito, Naoki; Ruegg, Urs T; Kudo, Akira; Miyagoe-Suzuki, Yuko; Takeda, Shin'ichi

    2013-01-01

    Mechanical load-induced intracellular signaling events are important for subsequent skeletal muscle hypertrophy. We previously showed that load-induced activation of the cation channel TRPV1 caused an increase in intracellular calcium concentrations ([Ca ( 2+) ]i) and that this activated mammalian target of rapamycin (mTOR) and promoted muscle hypertrophy. However, the link between mechanical load-induced intracellular signaling events, and the TRPV1-mediated increases in [Ca ( 2+) ]i are not fully understood. Here we show that administration of the TRPV1 agonist, capsaicin, induces phosphorylation of mTOR, p70S6K, S6, Erk1/2 and p38 MAPK, but not Akt, AMPK or GSK3β. Furthermore, the TRPV1-induced phosphorylation patterns resembled those induced by mechanical load. Our results continue to highlight the importance of TRPV1-mediated calcium signaling in load-induced intracellular signaling pathways.

  20. The solvent effect on two competing reaction mechanisms involving hypervalent iodine reagents (λ(3)-iodanes): facing the limit of the stationary quantum chemical approach.

    Science.gov (United States)

    Sala, Oliver; Lüthi, Hans Peter; Togni, Antonio

    2014-11-05

    Trifluoromethylation of acetonitrile with 3,3-dimethyl-1-(trifluoromethyl)-1λ(3),2- benziodoxol is assumed to occur via reductive elimination (RE) of the electrophilic CF3-ligand and MeCN bound to the hypervalent iodine. Computations in gas phase showed that the reaction might also occur via an SN2 mechanism. There is a substantial solvent effect present for both reaction mechanisms, and their energies of activation are very sensitive toward the solvent model used (implicit, microsolvation, and cluster-continuum). With polarizable continuum model-based methods, the SN2 mechanism becomes less favorable. Applying the cluster-continuum model, using a shell of solvent molecules derived from ab initio molecular dynamics (AIMD) simulations, the gap between the two activation barriers ( ΔΔG‡) is lowered to a few kcal mol(-1) and also shows that the activation entropies (ΔS‡) and volumes (ΔV‡) for the two mechanisms differ substantially. A quantitative assessment of ΔΔG‡ will therefore only be possible using AIMD. A natural bond orbital-analysis gives further insight into the activation of the CF3-reagent by protonation.

  1. Mechanisms involved in control of ¤Blumeria graminis¤ f.sp. ¤hordei¤ in barley treated with mycelial extracts from cultured fungi

    DEFF Research Database (Denmark)

    Haugaard, H.; Collinge, D.B.; Lyngkjær, Michael Foged

    2002-01-01

    Treatment with mycelial extracts, prepared from liquid cultures of Bipolaris oryzae , Pythium ultimum and Rhizopus stolonifer , protected barley (Hordeum vulgare ) against powdery mildew disease caused by the fungus Blumeria graminis f.sp. hordei . The mechanisms of this protection were studied...

  2. The Union Involved in the Mechanism of the Social Construction%工会参与社会建设的机制研究

    Institute of Scientific and Technical Information of China (English)

    纪荣凯

    2012-01-01

    Chinese trade unions as a bridge between the party and the masses of workers in the social construction which can not be replaced by any social organization. In order to fully release the participation in the social construction and give better play to organizing employees, guiding the workers, serving workers and safeguarding the legitimate rights and interests, the trade unions must build and continue to improve macroparticipation mechanism, maintaining the potential of the working mechanism of the workers' rights, long-term workers mechanism, employee groups and unexpected events to prevent emergency response mechanism, employees of public opinion to guide and ease the mechanism.%中国工会作为党联系职工群众的桥梁纽带,在社会建设中的作用是任何社会组织不可替代的。工会必须构建并不断完善宏观参与机制、维护职工权益工作机制、长效化的职工服务机制、职工群体性突发性事件预防应急机制、职工舆情引导和疏导机制,才能充分释放参与社会建设的潜力,更好地发挥组织职工、引导职工、服务职工和维护职工合法权益的重要作用。

  3. A murine experimental anthracycline extravasation model: pathology and study of the involvement of topoisomerase II alpha and iron in the mechanism of tissue damage

    DEFF Research Database (Denmark)

    2010-01-01

    The bisdioxopiperazine topoisomerase II catalytic inhibitor dexrazoxane has successfully been introduced into the clinic as an antidote to accidental anthracycline extravasation based on our preclinical mouse studies. The histology of this mouse extravasation model was investigated and found...... with dense dermal connective tissue. The extension of this fibrosis was quantified, and dexrazoxane intervention resulted in a statistically significant decrease in fibrosis extension, as also observed in the clinic. Several mechanisms have been proposed in anthracycline extravasation cytotoxicity, and we...... tested two major hypotheses: (1) interaction with topoisomerase II alpha and (2) the formation of tissue damaging reactive oxygen species following redox cycling of an anthracycline Fe(2+) complex. Dexrazoxane could minimise skin damage via both mechanisms, as it stops the catalytic activity...

  4. A novel antibody-dependent cellular cytotoxicity mechanism involved in defense against malaria requires costimulation of monocytes FcgammaRII and FcgammaRIII

    DEFF Research Database (Denmark)

    Jafarshad, Ali; Dziegiel, Morten Hanefeld; Lundquist, Rasmus

    2007-01-01

    Clinical experiments have shown that the Ab-dependent cell-mediated inhibition of Plasmodium falciparum is a major mechanism controlling malaria parasitemia and thereby symptoms. In this study, we demonstrate that a single merozoite per monocyte (MN) is sufficient to trigger optimal antiparasitic......-dependent cellular cytotoxicity and implies that all MN are not equally effective. These findings have both fundamental and practical implications, particularly for vaccine discovery....

  5. Role of the Renin-Angiotensin-Aldosterone System beyond Blood Pressure Regulation: Molecular and Cellular Mechanisms Involved in End-Organ Damage during Arterial Hypertension.

    Science.gov (United States)

    Muñoz-Durango, Natalia; Fuentes, Cristóbal A; Castillo, Andrés E; González-Gómez, Luis Martín; Vecchiola, Andrea; Fardella, Carlos E; Kalergis, Alexis M

    2016-06-23

    Arterial hypertension is a common condition worldwide and an important predictor of several complicated diseases. Arterial hypertension can be triggered by many factors, including physiological, genetic, and lifestyle causes. Specifically, molecules of the renin-angiotensin-aldosterone system not only play important roles in the control of blood pressure, but they are also associated with the genesis of arterial hypertension, thus constituting a need for pharmacological interventions. Chronic high pressure generates mechanical damage along the vascular system, heart, and kidneys, which are the principal organs affected in this condition. In addition to mechanical stress, hypertension-induced oxidative stress, chronic inflammation, and the activation of reparative mechanisms lead to end-organ damage, mainly due to fibrosis. Clinical trials have demonstrated that renin-angiotensin-aldosterone system intervention in hypertensive patients lowers morbidity/mortality and inflammatory marker levels as compared to placebo patients, evidencing that this system controls more than blood pressure. This review emphasizes the detrimental effects that a renin-angiotensin-aldosterone system (RAAS) imbalance has on health considerations above and beyond high blood pressure, such as fibrotic end-organ damage.

  6. Characterization of large deletions occurring during a single round of retrovirus vector replication: novel deletion mechanism involving errors in strand transfer.

    Science.gov (United States)

    Pulsinelli, G A; Temin, H M

    1991-09-01

    Retroviruses mutate at a high rate during replication. We used a spleen necrosis virus-based vector system and helper cell line to characterize mutations occurring during a single round of retrovirus replication. The vector used, JD216HyNeo, codes for two drug resistance genes, hygromycin resistance (hygro) and neomycin resistance (neo). The downstream neo gene is expressed only when a mutation alleviates a block to splicing which is located in the upstream hygro gene. The mutations allowing splicing were large deletions, ranging in size from about 500 to about 2,000 bp. Most of the mutant proviruses lacked the encapsidation sequence, as shown by our inability to rescue the mutant proviruses with wild-type reticuloendotheliosis virus strain A and confirmed by Southern blotting and direct DNA sequence analysis. We therefore concluded that most of the deletions arose during reverse transcription in the target cell, rather than during transcription in the host cell. The sequence data also indicated that the deletions occurred by at least three different mechanisms: (i) misalignment of the growing point; (ii) incorrect synthesis and termination in the primer-binding sequence during synthesis of the plus-strand strong-stop DNA; and (iii) incorrect synthesis and termination before the primer-binding sequence during synthesis of the plus-strand strong-stop DNA. The second mechanism also led to the incorporation of cellular sequences into the proviral genome, pointing to a potential novel mechanism by which retroviruses can acquire cellular genes.

  7. 肝窦内皮细胞参与肝纤维化的机制%Mechanism of liver sinusoidal endothelial cells involved in liver fibrosis

    Institute of Scientific and Technical Information of China (English)

    李娟梅; 闫洁; 吕文良; 陈兰羽; 徐晨光

    2013-01-01

    肝窦内皮细胞在肝纤维发生发展过程中具有重要作用.它主要通过表达相关细胞因子、介导肝脏炎症反应、活化星状细胞、参与细胞外基质的生成与降解、参与肝窦毛细血管化、调节肝脏血管等参与肝纤维化.本文就肝窦内皮细胞与肝纤维化的机制进行综述.%Sinusoidal endothelial cells play an important role in the development of liver fibrogenesis. It is mainly through the expression of cytokines, mediation of liver inflammation, activation of hepatic satelliteell, involvment in the generation and degradation of extracellular matrix, participation in the sinusoidal capillarization and regulation of the liver vascular involved in liver fibrosis.

  8. Traf2- and Nck-interacting kinase (TNIK) is involved in the anti-cancer mechanism of dovitinib in human multiple myeloma IM-9 cells.

    Science.gov (United States)

    Chon, Hae Jung; Lee, Yura; Bae, Kyoung Jun; Byun, Byung Jin; Kim, Soon Ae; Kim, Jiyeon

    2016-07-01

    Traf2- and Nck-interacting kinase (TNIK) is a member of the germinal center kinase family. TNIK was first identified as a kinase that is involved in regulating cytoskeletal organization in many types of cells, and it was recently proposed as a novel therapeutic target in several types of human cancers. Although previous studies suggest that TNIK plays a pivotal role in cancer cell survival and prognosis, its function in hematological cancer cell survival has not been investigated. Here we investigated the relationship between TNIK function and cell viability in multiple myeloma IM-9 cells using TNIK small interfering RNA (siRNA) transfection and dovitinib treatment. Treatment of IM-9 cells with TNIK siRNA and dovitinib treatment reduced cell proliferation. The ATP competing kinase assay and western blot analysis showed that dovitinib strongly inhibited both the interaction of TNIK with ATP (K i, 13 nM) and the activation of Wnt signaling effectors such as β-catenin and TCF4. Dovitinib also induced caspase-dependent apoptosis in IM-9 cells without significant cytotoxicity in PBMCs. Our results provide new evidence that TNIK may be involved in the proliferation of multiple myeloma IM-9 cells and in the anti-cancer activity of dovitinib via inhibition of the endogenous Wnt signaling pathway.

  9. Acutely applied MDMA enhances long-term potentiation in rat hippocampus involving D1/D5 and 5-HT2 receptors through a polysynaptic mechanism.

    Science.gov (United States)

    Rozas, C; Loyola, S; Ugarte, G; Zeise, M L; Reyes-Parada, M; Pancetti, F; Rojas, P; Morales, B

    2012-08-01

    3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) is a drug of abuse that induces learning and memory deficit. However, there are no experimental data that correlate the behavioral evidence with models of synaptic plasticity such as long-term potentiation (LTP) or long-term depression (LTD). Using field potential recordings in rat hippocampal slices of young rats, we found that acute application of MDMA enhances LTP in CA3-CA1 synapses without affecting LTD. Using specific antagonists and paired-pulse facilitation protocols we observed that the MDMA-dependent increase of LTP involves presynaptic 5-HT₂ serotonin receptors and postsynaptic D1/D5 dopamine receptors. In addition, the inhibition of PKA suppresses the MDMA-dependent increase in LTP, suggesting that dopamine receptor agonism activates cAMP-dependent intracellular pathways. We propose that MDMA exerts its LTP-altering effect involving a polysynaptic interaction between serotonergic and dopaminergic systems in hippocampal synapses. Our results are compatible with the view that the alterations in hippocampal LTP could be responsible for MDMA-dependent cognitive deficits observed in humans and animals.

  10. Hepatic transcriptional analysis in rats treated with Cassia occidentalis seed: involvement of oxidative stress and impairment in xenobiotic metabolism as a putative mechanism of toxicity.

    Science.gov (United States)

    Panigrahi, Gati Krushna; Yadav, Ashish; Yadav, Anuradha; Ansari, Kausar M; Chaturvedi, Rajnish K; Vashistha, Vipin M; Raisuddin, S; Das, Mukul

    2014-08-17

    The present study was undertaken to investigate the effect of Cassia occidentalis (CO) seeds on the transcriptional expression patterns of mRNAs in rat liver by microarray analysis. The results indicated that exposure of CO (0.5%) seeds in diet to rats differentially regulated 60 transcripts belonging to various metabolic pathways including, oxidative stress, xenobiotic metabolism, carbohydrate metabolism, cell cycle, apoptosis etc. The expression of AKT1, CAT, SOD1, CYP1A1, CYP2B1, TGF-β, BAX, CREB1, JNK1 and IL-6 were validated by the qRT-PCR. In addition, involvement of oxidative stress was observed due to marked depletion of glutathione, increase in lipid peroxidation and modulation of antioxidant enzymes in hepatic tissue of rats treated with 0.5-2.0% CO in diet. Furthermore, significant decrease in the levels of Phase 1 (EROD, MROD and PROD) and Phase 2 (QR and GST) enzymes following 0.5-2.0% CO exposure indicates the impairment of xenobiotic metabolism and possible accumulation of toxic ingredients of the seeds in liver. Overall, the study predicts the involvement of multiple pathways and related biomolecules in CO induced hepatotoxicity and the data may be useful in formulating strategies for therapeutic interventions of suspected CO poisoning study cases.

  11. Impact of vasculature damage on the outcome of spinal cord injury:a novel collagenase-induced model may give new insights into the mechanisms involved

    Institute of Scientific and Technical Information of China (English)

    Patrick Losey; Daniel C. Anthony

    2014-01-01

    The deleterious effect of vasculature damage on the outcome of spinal cord injury has long been recognized, and numerous clinical studies have shown that the presence of hemorrhage into the spinal cord is directly associated with a poorer neurological outcome. Vascular damage leads to de-creased blood lfow to the cord and the release of potentially toxic blood-borne components. Here we consider the mechanisms that may be contributing to hemorrhage-induced damage and discuss the utility of a new model of spinal cord hemorrhage, which was urgently required as most of our current understanding has been extrapolated from intracerebral hemorrhage studies.

  12. Low Constitutive Cell Surface Expression of HLA-B Is Caused by a Posttranslational Mechanism Involving Glu180 and Arg239

    DEFF Research Database (Denmark)

    Dellgren, Christoffer; Ekwelum, Vanessa A. C.; Ormhøj, Maria

    2016-01-01

    HLA class I cell surface expression is crucial for normal immune responses, and variability in HLA expression may influence the course of infections. We have previously shown that classical HLA class I expression on many human cell types is biased with greatly reduced expression of HLA-B compared...... with HLA-A in the absence of inflammatory signals. In the search for the mechanisms responsible for this discrepancy, we have recently reported that the regulation is mainly posttranslational and that the C-terminal part of the α2 domain and the α3 domain contain the molecular determinants that explain...

  13. PERK-eIF2α-ATF4 pathway mediated by endoplasmic reticulum stress response is involved in osteodifferentiation of human periodontal ligament cells under cyclic mechanical force.

    Science.gov (United States)

    Yang, Shuang-Yan; Wei, Fu-Lan; Hu, Li-Hua; Wang, Chun-Ling

    2016-08-01

    To prevent excess accumulation of unfolded proteins in endoplasmic reticulum (ER), eukaryotic cells have signaling pathways from the ER to the cytosol or nucleus. These processes are known as the endoplasmic reticulum stress (ERS) response. Protein kinase R like endoplasmic reticulum kinase (PERK) is a major transducer of the ERS response and it directly phosphorylate α-subunit of eukaryotic initiation factor 2 (eIF2α), resulting in translational attenuation. Phosphorylated eIF2α specifically promoted the translation of the activating transcription factor 4 (ATF4). ATF4 is a known important transcription factor which plays a pivotal role in osteoblast differentiation and bone formation. Furthermore, ATF4 is a downstream target of PERK. Studies have shown that PERK-eIF2α-ATF4 signal pathway mediated by ERS was involved in osteoblastic differentiation of osteoblasts. We have known that orthodontic tooth movement is a process of periodontal ligament cells (PDLCs) osteodifferentiation and alveolar bone remodeling under mechanical force. However, the involvement of PERK-eIF2α-ATF4 signal pathway mediated by ERS in osteogenic differentiation of PDLCs under mechanical force has not been unclear. In our study, we applied the cyclic mechanical force at 10% elongation with 0.5Hz to mimic occlusal force, and explored whether PERK-eIF2α-ATF4 signaling pathway mediated by ERS involved in osteogenic differentiation of PDLCs under mechanical force. Firstly, cyclic mechanical force will induce ERS and intensify several osteoblast marker genes (ATF4, OCN, and BSP). Next, we found that PERK overexpression increased eIF2α phosphorylation and expression of ATF4, furthermore induced BSP, OCN expression, thus it will promote osteodifferentiation of hPDLCs; mechanical force could promote this effect. However, PERK(-/-) cells showed the opposite changes, which will inhibit osteodifferentiation of hPDLCs. Taken together, our study proved that PERK-eIF2α-ATF4 signaling pathway

  14. MyD88 drives the IFN-ß response to Lactobacillus acidophilus in dendritic cells through a mechanism involving IRF1, IRF3, and IRF7

    DEFF Research Database (Denmark)

    Weiss, Gudrun Margarethe; Maaetoft-Udsen, Kristina; Stifter, Sebastian A.

    2012-01-01

    Type I IFNs are induced by pathogens to protect the host from infection and boost the immune response. We have recently demonstrated that this IFN response is not restricted to pathogens, as the Gram-positive bacterium Lactobacillus acidophilus, a natural inhabitant of the intestine, induces high...... levels of IFN-ß in dendritic cells. In the current study, we investigate the intracellular pathways involved in IFN-ß upon stimulation of dendritic cells with L. acidophilus and reveal that this IFN-ß induction requires phagosomal uptake and processing but bypasses the endosomal receptors TLR7 and TLR9......-ß signaling. The IFN-ß production is strongly impaired by inhibitors of spleen tyrosine kinase (Syk) and PI3K. Our results indicate that L. acidophilus induces IFN-ß independently of the receptors typically used by bacteria, as it requires MyD88, Syk, and PI3K signaling and phagosomal processing to activate...

  15. Deleted in malignant brain tumour 1 (DMBT1) is secreted in the oviduct and involved in the mechanism of fertilization in equine and porcine species

    DEFF Research Database (Denmark)

    Ambruosi, Barbara; Accogli, Gianluca; Douet, Cecile;

    2013-01-01

    fertilization (IVF) in porcine and equine species that represent divergent IVF models. We first performed IVF after pre-incubation of oocytes with or without oviductal fluid supplemented or not with antibodies directed against DMBT1. We showed that oviductal fluid induces an increase of the monospermic...... fertilization rate, and that this effect is cancelled by the addition of antibodies, in both porcine and equine species. Moreover, pre-incubation of oocytes with recombinant DMBT1 induces an increase of the monospermic fertilization rate in the pig, confirming an involvement of DMBT1 in the fertilization...... in the zona pellucida and cytoplasm of equine and porcine oocytes was observed using immunofluorescence analysis and confocal microscopy. Moreover, we showed an interaction between DMBT1 and porcine spermatozoa using surface plasmon resonance studies. Finally, a bioinformatics and phylogenetic analysis...