The effects of HIV-1 regulatory TAT protein expression on brain reward function, response to psychostimulants and delay-dependent memory in mice.

Science.gov (United States)

Kesby, James P; Markou, Athina; Semenova, Svetlana

2016-10-01

Depression and psychostimulant abuse are common comorbidities among humans with immunodeficiency virus (HIV) disease. The HIV regulatory protein TAT is one of multiple HIV-related proteins associated with HIV-induced neurotoxicity. TAT-induced dysfunction of dopamine and serotonin systems in corticolimbic brain areas may result in impaired reward function, thus, contributing to depressive symptoms and psychostimulant abuse. Transgenic mice with doxycycline-induced TAT protein expression in the brain (TAT+, TAT- control) show neuropathology resembling brain abnormalities in HIV+ humans. We evaluated brain reward function in response to TAT expression, nicotine and methamphetamine administration in TAT+ and TAT- mice using the intracranial self-stimulation procedure. We evaluated the brain dopamine and serotonin systems with high-performance liquid chromatography. The effects of TAT expression on delay-dependent working memory in TAT+ and TAT- mice using the operant delayed nonmatch-to-position task were also assessed. During doxycycline administration, reward thresholds were elevated by 20% in TAT+ mice compared with TAT- mice. After the termination of doxycycline treatment, thresholds of TAT+ mice remained significantly higher than those of TAT- mice and this was associated with changes in mesolimbic serotonin and dopamine levels. TAT+ mice showed a greater methamphetamine-induced threshold lowering compared with TAT- mice. TAT expression did not alter delay-dependent working memory. These results indicate that TAT expression in mice leads to reward deficits, a core symptom of depression, and a greater sensitivity to methamphetamine-induced reward enhancement. Our findings suggest that the TAT protein may contribute to increased depressive-like symptoms and continued methamphetamine use in HIV-positive individuals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Potent inhibition of HIV-1 replication by a Tat mutant.

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Luke W Meredith

Full Text Available Herein we describe a mutant of the two-exon HIV-1 Tat protein, termed Nullbasic, that potently inhibits multiple steps of the HIV-1 replication cycle. Nullbasic was created by replacing the entire arginine-rich basic domain of wild type Tat with glycine/alanine residues. Like similarly mutated one-exon Tat mutants, Nullbasic exhibited transdominant negative effects on Tat-dependent transactivation. However, unlike previously reported mutants, we discovered that Nullbasic also strongly suppressed the expression of unspliced and singly-spliced viral mRNA, an activity likely caused by redistribution and thus functional inhibition of HIV-1 Rev. Furthermore, HIV-1 virion particles produced by cells expressing Nullbasic had severely reduced infectivity, a defect attributable to a reduced ability of the virions to undergo reverse transcription. Combination of these inhibitory effects on transactivation, Rev-dependent mRNA transport and reverse transcription meant that permissive cells constitutively expressing Nullbasic were highly resistant to a spreading infection by HIV-1. Nullbasic and its activities thus provide potential insights into the development of potent antiviral therapeutics that target multiple stages of HIV-1 infection.

Therapeutic immunization with HIV-1 Tat reduces immune activation and loss of regulatory T-cells and improves immune function in subjects on HAART.

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Barbara Ensoli

2010-11-01

Full Text Available Although HAART suppresses HIV replication, it is often unable to restore immune homeostasis. Consequently, non-AIDS-defining diseases are increasingly seen in treated individuals. This is attributed to persistent virus expression in reservoirs and to cell activation. Of note, in CD4(+ T cells and monocyte-macrophages of virologically-suppressed individuals, there is continued expression of multi-spliced transcripts encoding HIV regulatory proteins. Among them, Tat is essential for virus gene expression and replication, either in primary infection or for virus reactivation during HAART, when Tat is expressed, released extracellularly and exerts, on both the virus and the immune system, effects that contribute to disease maintenance. Here we report results of an ad hoc exploratory interim analysis (up to 48 weeks on 87 virologically-suppressed HAART-treated individuals enrolled in a phase II randomized open-label multicentric clinical trial of therapeutic immunization with Tat (ISS T-002. Eighty-eight virologically-suppressed HAART-treated individuals, enrolled in a parallel prospective observational study at the same sites (ISS OBS T-002, served for intergroup comparison. Immunization with Tat was safe, induced durable immune responses, and modified the pattern of CD4(+ and CD8(+ cellular activation (CD38 and HLA-DR together with reduction of biochemical activation markers and persistent increases of regulatory T cells. This was accompanied by a progressive increment of CD4(+ T cells and B cells with reduction of CD8(+ T cells and NK cells, which were independent from the type of antiretroviral regimen. Increase in central and effector memory and reduction in terminally-differentiated effector memory CD4(+ and CD8(+ T cells were accompanied by increases of CD4(+ and CD8(+ T cell responses against Env and recall antigens. Of note, more immune-compromised individuals experienced greater therapeutic effects. In contrast, these changes were opposite

Functional substitution by TAT-utrophin in dystrophin-deficient mice.

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Kevin J Sonnemann

2009-05-01

Full Text Available The loss of dystrophin compromises muscle cell membrane stability and causes Duchenne muscular dystrophy and/or various forms of cardiomyopathy. Increased expression of the dystrophin homolog utrophin by gene delivery or pharmacologic up-regulation has been demonstrated to restore membrane integrity and improve the phenotype in the dystrophin-deficient mdx mouse. However, the lack of a viable therapy in humans predicates the need to explore alternative methods to combat dystrophin deficiency. We investigated whether systemic administration of recombinant full-length utrophin (Utr or DeltaR4-21 "micro" utrophin (muUtr protein modified with the cell-penetrating TAT protein transduction domain could attenuate the phenotype of mdx mice.Recombinant TAT-Utr and TAT-muUtr proteins were expressed using the baculovirus system and purified using FLAG-affinity chromatography. Age-matched mdx mice received six twice-weekly intraperitoneal injections of either recombinant protein or PBS. Three days after the final injection, mice were analyzed for several phenotypic parameters of dystrophin deficiency. Injected TAT-muUtr transduced all tissues examined, integrated with members of the dystrophin complex, reduced serum levels of creatine kinase (11,290+/-920 U versus 5,950+/-1,120 U; PBS versus TAT, the prevalence of muscle degeneration/regeneration (54%+/-5% versus 37%+/-4% of centrally nucleated fibers; PBS versus TAT, the susceptibility to eccentric contraction-induced force drop (72%+/-5% versus 40%+/-8% drop; PBS versus TAT, and increased specific force production (9.7+/-1.1 N/cm(2 versus 12.8+/-0.9 N/cm(2; PBS versus TAT.These results are, to our knowledge, the first to establish the efficacy and feasibility of TAT-utrophin-based constructs as a novel direct protein-replacement therapy for the treatment of skeletal and cardiac muscle diseases caused by loss of dystrophin.

Combined metabonomic and quantitative real-time PCR analyses reveal systems metabolic changes in Jurkat T-cells treated with HIV-1 Tat protein.

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Liao, Wenting; Tan, Guangguo; Zhu, Zhenyu; Chen, Qiuli; Lou, Ziyang; Dong, Xin; Zhang, Wei; Pan, Wei; Chai, Yifeng

2012-11-02

HIV-1 Tat protein is released by infected cells and can affect bystander uninfected T cells and induce numerous biological responses which contribute to its pathogenesis. To elucidate the complex pathogenic mechanism, we conducted a comprehensive investigation on Tat protein-related extracellular and intracellular metabolic changes in Jurkat T-cells using combined gas chromatography-mass spectrometry (GC-MS), reversed-phase liquid chromatography-mass spectrometry (RPLC-MS) and a hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-MS)-based metabonomics approach. Quantitative real-time PCR (qRT-PCR) analyses were further employed to measure expressions of several relevant enzymes together with perturbed metabolic pathways. Combined metabonomic and qRT-PCR analyses revealed that HIV-1 Tat caused significant and comprehensive metabolic changes, as represented by significant changes of 37 metabolites and 10 relevant enzymes in HIV-1 Tat-treated cells. Using MetaboAnalyst 2.0, it was found that 11 pathways (Impact-value >0.10) among the regulated pathways were acutely perturbed, including sphingolipid metabolism, glycine, serine and threonine metabolism, pyruvate metabolism, inositol phosphate metabolism, arginine and proline metabolism, citrate cycle, phenylalanine metabolism, tryptophan metabolism, pentose phosphate pathway, glycerophospholipid metabolism, glycolysis or gluconeogenesis. These results provide metabolic evidence of the complex pathogenic mechanism of HIV-1 Tat protein as a "viral toxin", and would help obligate Tat protein as "an important target" for therapeutic intervention and vaccine development.

In vitro nuclear interactome of the HIV-1 Tat protein.

LENUS (Irish Health Repository)

Gautier, Virginie W

2009-01-01

BACKGROUND: One facet of the complexity underlying the biology of HIV-1 resides not only in its limited number of viral proteins, but in the extensive repertoire of cellular proteins they interact with and their higher-order assembly. HIV-1 encodes the regulatory protein Tat (86-101aa), which is essential for HIV-1 replication and primarily orchestrates HIV-1 provirus transcriptional regulation. Previous studies have demonstrated that Tat function is highly dependent on specific interactions with a range of cellular proteins. However they can only partially account for the intricate molecular mechanisms underlying the dynamics of proviral gene expression. To obtain a comprehensive nuclear interaction map of Tat in T-cells, we have designed a proteomic strategy based on affinity chromatography coupled with mass spectrometry. RESULTS: Our approach resulted in the identification of a total of 183 candidates as Tat nuclear partners, 90% of which have not been previously characterised. Subsequently we applied in silico analysis, to validate and characterise our dataset which revealed that the Tat nuclear interactome exhibits unique signature(s). First, motif composition analysis highlighted that our dataset is enriched for domains mediating protein, RNA and DNA interactions, and helicase and ATPase activities. Secondly, functional classification and network reconstruction clearly depicted Tat as a polyvalent protein adaptor and positioned Tat at the nexus of a densely interconnected interaction network involved in a range of biological processes which included gene expression regulation, RNA biogenesis, chromatin structure, chromosome organisation, DNA replication and nuclear architecture. CONCLUSION: We have completed the in vitro Tat nuclear interactome and have highlighted its modular network properties and particularly those involved in the coordination of gene expression by Tat. Ultimately, the highly specialised set of molecular interactions identified will

HIV-1 tat protein recruits CIS to the cytoplasmic tail of CD127 to induce receptor ubiquitination and proteasomal degradation

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Sugden, Scott, E-mail: scott.sugden@ircm.qc.ca [The Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario, Canada K1H 8L6 (Canada); Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5 (Canada); Ghazawi, Feras [The Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario, Canada K1H 8L6 (Canada); Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5 (Canada); MacPherson, Paul, E-mail: pmacpherson@toh.on.ca [The Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario, Canada K1H 8L6 (Canada); Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5 (Canada); Division of Infectious Diseases, The Ottawa Hospital General Campus, 501 Smyth Road, Ottawa, Ontario, Canada K1H 8L6 (Canada)

2016-11-15

HIV-1 Tat protein down regulates expression of the IL-7 receptor alpha-chain (CD127) from the surface of CD8 T cells resulting in impaired T cell proliferation and cytolytic capacity. We have previously shown that soluble Tat protein is taken up by CD8 T cells and interacts with the cytoplasmic tail of CD127 to induce receptor degradation. The N-terminal domain of Tat interacts with CD127 while the basic domain directs CD127 to the proteasome. We have also shown that upon IL-7 binding to its receptor, CD127 is phosphorylated resulting in CIS-mediated proteasomal degradation. Here, we show that Tat mimics this process by recruiting CIS to CD127 in the absence of IL-7 and receptor phosphorylation, leading to CD127 ubiquitination and degradation. Tat therefore acts as an adapter to induce cellular responses under conditions where they may not otherwise occur. Thusly, Tat reduces IL-7 signaling and impairs CD8 T cell survival and function. -- Highlights: •Soluble HIV-1 Tat decreases CD127 expression on CD8 T cells, causing dysfunction. •Tat induces CD127 ubiquitination without activating IL-7 signaling. •Tat binds CD127 and recruits the E3 ubiquitin ligase CIS via its basic domain. •Tat hijacks a normal cellular mechanism to degrade CD127 without IL-7 signaling.

HIV-1 tat protein recruits CIS to the cytoplasmic tail of CD127 to induce receptor ubiquitination and proteasomal degradation

International Nuclear Information System (INIS)

Sugden, Scott; Ghazawi, Feras; MacPherson, Paul

2016-01-01

HIV-1 Tat protein down regulates expression of the IL-7 receptor alpha-chain (CD127) from the surface of CD8 T cells resulting in impaired T cell proliferation and cytolytic capacity. We have previously shown that soluble Tat protein is taken up by CD8 T cells and interacts with the cytoplasmic tail of CD127 to induce receptor degradation. The N-terminal domain of Tat interacts with CD127 while the basic domain directs CD127 to the proteasome. We have also shown that upon IL-7 binding to its receptor, CD127 is phosphorylated resulting in CIS-mediated proteasomal degradation. Here, we show that Tat mimics this process by recruiting CIS to CD127 in the absence of IL-7 and receptor phosphorylation, leading to CD127 ubiquitination and degradation. Tat therefore acts as an adapter to induce cellular responses under conditions where they may not otherwise occur. Thusly, Tat reduces IL-7 signaling and impairs CD8 T cell survival and function. -- Highlights: •Soluble HIV-1 Tat decreases CD127 expression on CD8 T cells, causing dysfunction. •Tat induces CD127 ubiquitination without activating IL-7 signaling. •Tat binds CD127 and recruits the E3 ubiquitin ligase CIS via its basic domain. •Tat hijacks a normal cellular mechanism to degrade CD127 without IL-7 signaling.

HIV-1 Tat C-mediated regulation of tumor necrosis factor receptor-associated factor-3 by microRNA 32 in human microglia

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Mishra Ritu

2012-06-01

Full Text Available Abstract Background HIV-1 Tat protein is known to be associated with neuroinflammation, a condition that develops in almost half of patients infected with HIV-1. HIV-1 Tat can alter glial neuroprotective functions, leading to neurotoxicity within the CNS. HIV-1 Tat is known to be secreted from productively infected cells and can affect neighboring uninfected cells by modulating cellular gene expression in a bystander fashion. Methods We were interested to study whether exogenous exposure to HIV-1 Tat-C protein perturbs the microRNA (miRNA expression profile of human microglial cells, leading to altered protein expression. We used protein expression and purification, miRNA overexpression, miRNA knockdown, transfection, site-directed mutagenesis, real-time PCR, luciferase assay and western blotting techniques to perform our study. Results HIV-1 Tat-C treatment of human microglial cells resulted in a dose-dependent increase in miR-32 expression. We found that tumor necrosis factor-receptor–associated factor 3 TRAF3 is a direct target for miR-32, and overexpression of miR-32 in CHME3 cells decreased TRAF3 both at the mRNA and the protein level. Recovery of TRAF3 protein expression after transfection of anti-miR-32 and the results of the luciferase reporter assay provided direct evidence of TRAF3 regulation by miR-32. We found that the regulation of interferon regulatory factor 3 (IRF3 and IRF7 is controlled by cellular levels of TRAF3 protein in microglial cells, as after overexpression of miR-32 and application of anti-miR-32, expression levels of IRF3 and IRF7 were inversely regulated by expression levels of TRAF3. Thus, our results suggest a novel miRNA mediated mechanism for regulation of TRAF3 in human microglial cells exposed to HIV-1 Tat C protein. These results may help to elucidate the detrimental neuroinflammatory consequences of HIV-1 Tat C protein in bystander fashion. Conclusion HIV-1 Tat protein can modulate TRAF3 expression through

Conjugation to the cell-penetrating peptide TAT potentiates the photodynamic effect of carboxytetramethylrhodamine.

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Divyamani Srinivasan

2011-03-01

Full Text Available Cell-penetrating peptides (CPPs can transport macromolecular cargos into live cells. However, the cellular delivery efficiency of these reagents is often suboptimal because CPP-cargo conjugates typically remain trapped inside endosomes. Interestingly, irradiation of fluorescently labeled CPPs with light increases the release of the peptide and its cargos into the cytosol. However, the mechanism of this phenomenon is not clear. Here we investigate the molecular basis of the photo-induced endosomolytic activity of the prototypical CPPs TAT labeled to the fluorophore 5(6-carboxytetramethylrhodamine (TMR.We report that TMR-TAT acts as a photosensitizer that can destroy membranes. TMR-TAT escapes from endosomes after exposure to moderate light doses. However, this is also accompanied by loss of plasma membrane integrity, membrane blebbing, and cell-death. In addition, the peptide causes the destruction of cells when applied extracellularly and also triggers the photohemolysis of red blood cells. These photolytic and photocytotoxic effects were inhibited by hydrophobic singlet oxygen quenchers but not by hydrophilic quenchers.Together, these results suggest that TAT can convert an innocuous fluorophore such as TMR into a potent photolytic agent. This effect involves the targeting of the fluorophore to cellular membranes and the production of singlet oxygen within the hydrophobic environment of the membranes. Our findings may be relevant for the design of reagents with photo-induced endosomolytic activity. The photocytotoxicity exhibited by TMR-TAT also suggests that CPP-chromophore conjugates could aid the development of novel Photodynamic Therapy agents.

Celastrol ameliorates HIV-1 Tat-induced inflammatory responses via NF-kappaB and AP-1 inhibition and heme oxygenase-1 induction in astrocytes

International Nuclear Information System (INIS)

Youn, Gi Soo; Kwon, Dong-Joo; Ju, Sung Mi; Rhim, Hyangshuk; Bae, Yong Soo; Choi, Soo Young; Park, Jinseu

2014-01-01

HIV-1 Tat causes extensive neuroinflammation that may progress to AIDS-related encephalitis and dementia. Celastrol possesses various biological activities such as anti-oxidant, anti-tumor, and anti-inflammatory activities. In this study, we investigated the modulatory effects of celastrol on HIV-1 Tat-induced inflammatory responses and the molecular mechanisms underlying its action in astrocytes. Pre-treatment of CRT-MG human astroglioma cells with celastrol significantly inhibited HIV-1 Tat-induced expression of ICAM-1/VCAM-1 and subsequent monocyte adhesiveness in CRT-MG cells. In addition, celastrol suppressed HIV-1 Tat-induced expression of pro-inflammatory chemokines, such as CXCL10, IL-8, and MCP-1. Celastrol decreased HIV-1 Tat-induced activation of JNK MAPK, AP-1, and NF-κB. Furthermore, celastrol induced mRNA and protein expression of HO-1 as well as Nrf2 activation. Blockage of HO-1 expression using siRNA reversed the inhibitory effect of celastrol on HIV-1 Tat-induced inflammatory responses. These results suggest that celastrol has regulatory effects on HIV-1 Tat-induced inflammatory responses by blocking the JNK MAPK-AP-1/NF-κB signaling pathways and inducing HO-1 expression in astrocytes. - Highlights: • Celastrol suppressed HIV-1 Tat-induced expression of pro-inflammatory genes. • Celastrol inhibited HIV-1 Tat -induced activation of JNK MAPK. • Celastrol inhibited HIV-1 Tat-induced activation of both NF-κB and AP-1. • Celastrol inhibited HIV-1 Tat-induced inflammatory responses via HO-1 induction

Celastrol ameliorates HIV-1 Tat-induced inflammatory responses via NF-kappaB and AP-1 inhibition and heme oxygenase-1 induction in astrocytes

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Youn, Gi Soo; Kwon, Dong-Joo; Ju, Sung Mi [Department of Biomedical Science and Research Institute for Bioscience and Biotechnology, Hallym University, Chunchon 200-702 (Korea, Republic of); Rhim, Hyangshuk [Department of Biomedical Sciences, Department of Medical Life Sciences, College of Medicine, the Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Bae, Yong Soo [Department of Biological Science, College of Natural Sciences, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Choi, Soo Young [Department of Biomedical Science and Research Institute for Bioscience and Biotechnology, Hallym University, Chunchon 200-702 (Korea, Republic of); Park, Jinseu, E-mail: jinpark@hallym.ac.kr [Department of Biomedical Science and Research Institute for Bioscience and Biotechnology, Hallym University, Chunchon 200-702 (Korea, Republic of)

2014-10-01

HIV-1 Tat causes extensive neuroinflammation that may progress to AIDS-related encephalitis and dementia. Celastrol possesses various biological activities such as anti-oxidant, anti-tumor, and anti-inflammatory activities. In this study, we investigated the modulatory effects of celastrol on HIV-1 Tat-induced inflammatory responses and the molecular mechanisms underlying its action in astrocytes. Pre-treatment of CRT-MG human astroglioma cells with celastrol significantly inhibited HIV-1 Tat-induced expression of ICAM-1/VCAM-1 and subsequent monocyte adhesiveness in CRT-MG cells. In addition, celastrol suppressed HIV-1 Tat-induced expression of pro-inflammatory chemokines, such as CXCL10, IL-8, and MCP-1. Celastrol decreased HIV-1 Tat-induced activation of JNK MAPK, AP-1, and NF-κB. Furthermore, celastrol induced mRNA and protein expression of HO-1 as well as Nrf2 activation. Blockage of HO-1 expression using siRNA reversed the inhibitory effect of celastrol on HIV-1 Tat-induced inflammatory responses. These results suggest that celastrol has regulatory effects on HIV-1 Tat-induced inflammatory responses by blocking the JNK MAPK-AP-1/NF-κB signaling pathways and inducing HO-1 expression in astrocytes. - Highlights: • Celastrol suppressed HIV-1 Tat-induced expression of pro-inflammatory genes. • Celastrol inhibited HIV-1 Tat -induced activation of JNK MAPK. • Celastrol inhibited HIV-1 Tat-induced activation of both NF-κB and AP-1. • Celastrol inhibited HIV-1 Tat-induced inflammatory responses via HO-1 induction.

Design and biological evaluation of 99mTc-N2S2-Tat(49–57)-c(RGDyK): A hybrid radiopharmaceutical for tumors expressing α(v)β(3) integrins

International Nuclear Information System (INIS)

Ocampo-García, Blanca E.; Santos-Cuevas, Clara L.; De León-Rodríguez, Luis M.; García-Becerra, Rocío; Ordaz-Rosado, David; Luna-Guitiérrez, Myrna A.; Jiménez-Mancilla, Nallely P.; Romero-Piña, Mario E.; Ferro-Flores, Guillermina

2013-01-01

The α(ν)β(3) integrin is over-expressed in the tumor neovasculature and the tumor cells of glioblastomas. The HIV Tat-derived peptide has been used to deliver various cargos into cells. The aim of this research was to synthesize and assess the in vitro and in vivo uptake of 99m Tc-N 2 S 2 -Tat(49–57)-c(RGDyK) ( 99m Tc-Tat-RGD) in α(ν)β(3) integrin positive cancer cells and compare it to that of a conventional 99m Tc-RGD peptide ( 99m Tc-EDDA/HYNIC-E-[c(RGDfK)] 2 ). Methods: The c(RGDyK) peptide was conjugated to a maleimidopropionyl (MP) moiety through Lys, and the MP group was used as the branch position to form a thioether with the Cys 12 side chain of the Tat(49–57)-spacer-N 2 S 2 peptide. 99m Tc-Tat-RGD was prepared, and stability studies were carried out by size exclusion HPLC analyses in human serum. The in vitro affinity for α(v)β(3) integrin was determined by a competitive binding assay. In vitro internalization was determined using glioblastoma C6 cells. Biodistribution studies were accomplished in athymic mice with C6 induced tumors that had blocked and unblocked receptors. Images were obtained using a micro-SPECT/CT. Results: 99m Tc-Tat-RGD was obtained with a radiochemical purity higher than 95%, as determined by radio-HPLC and ITLC-SG analyses. Protein binding was 15.7% for 99m Tc-Tat-RGD and 5.6% for 99m Tc-RGD. The IC 50 values were 6.7 nM ( 99m Tc-Tat-RGD) and 4.6 nM ( 99m Tc-RGD). Internalization in C6 cells was higher in 99m Tc-Tat-RGD (37.5%) than in 99m Tc-RGD (10%). Biodistribution studies and in vivo micro-SPECT/CT images in mice showed higher tumor uptake for 99m Tc-Tat-RGD (6.98% ± 1.34% ID/g at 3 h) than that of 99m Tc-RGD (3.72% ± 0.52% ID/g at 3 h) with specific recognition for α(v)β(3) integrins. Conclusions: Because of the significant cell internalization (Auger and internal conversion electrons) and specific recognition for α(v)β(3) integrins, the hybrid 99m Tc-N 2 S 2 -Tat(49–57)-c(RGDyK) radiopharmaceutical is

LRRK2 kinase inhibition prevents pathological microglial phagocytosis in response to HIV-1 Tat protein

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Marker Daniel F

2012-11-01

Full Text Available Abstract Background Human Immunodeficiency Virus-1 (HIV-1 associated neurocognitive disorders (HANDs are accompanied by significant morbidity, which persists despite the use of combined antiretroviral therapy (cART. While activated microglia play a role in pathogenesis, changes in their immune effector functions, including phagocytosis and proinflammatory signaling pathways, are not well understood. We have identified leucine-rich repeat kinase 2 (LRRK2 as a novel regulator of microglial phagocytosis and activation in an in vitro model of HANDs, and hypothesize that LRRK2 kinase inhibition will attenuate microglial activation during HANDs. Methods We treated BV-2 immortalized mouse microglia cells with the HIV-1 trans activator of transcription (Tat protein in the absence or presence of LRRK2 kinase inhibitor (LRRK2i. We used Western blot, qRT-PCR, immunocytochemistry and latex bead engulfment assays to analyze LRRK2 protein levels, proinflammatory cytokine and phagocytosis receptor expression, LRRK2 cellular distribution and phagocytosis, respectively. Finally, we utilized ex vivo microfluidic chambers containing primary hippocampal neurons and BV-2 microglia cells to investigate microglial phagocytosis of neuronal axons. Results We found that Tat-treatment of BV-2 cells induced kinase activity associated phosphorylation of serine 935 on LRRK2 and caused the formation of cytoplasmic LRRK2 inclusions. LRRK2i decreased Tat-induced phosphorylation of serine 935 on LRRK2 and inhibited the formation of Tat-induced cytoplasmic LRRK2 inclusions. LRRK2i also decreased Tat-induced process extension in BV-2 cells. Furthermore, LRRK2i attenuated Tat-induced cytokine expression and latex bead engulfment. We examined relevant cellular targets in microfluidic chambers and found that Tat-treated BV-2 microglia cells cleared axonal arbor and engulfed neuronal elements, whereas saline treated controls did not. LRRK2i was found to protect axons in the presence

Cell Type Preference of a Novel Human Derived Cell-Permeable Peptide dNP2 and TAT in Murine Splenic Immune Cells.

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Sangho Lim

Full Text Available Cell-permeable peptides (CPPs have been widely studied as an attractive drug delivery system to deliver therapeutic macromolecules such as DNA, RNA, and protein into cells. However, its clinical application is still limited and controversial due to the lack of a complete understanding of delivery efficiency in target cells. Previously we identified and characterized the novel and superior CPP, named dNP2, and here we comparatively analyzed intracellular delivery efficiency of dNP2 and TAT in various immune cells of mouse spleen to demonstrate their cell type preference. dNP2- or TAT-conjugated fluorescent proteins were most efficiently taken up by phagocytic cells such as dendritic cells and macrophages while little protein uptake was seen by lymphocytes including T cells, B cells, and NK cells. Interestingly CD8+ lymphoid dendritic cells and CD62LloCD44hi memory like T cell subsets showed significantly better uptake efficiency in vitro and in vivo relative to other dendritic cells or T cells, respectively. In addition, activated macrophages, T cells, and B cells took up the proteins more efficiently relative to when in the resting state. Importantly, only dNP2, not TAT, shows significant intracellular protein delivery efficiency in vivo. Collectively, this study provides important information regarding heterogeneous intracellular delivery efficiency of CPPs such as dNP2 and TAT with cell type preference in the spleen needed for its application in phagocytic cells or activated immune cells.

Epitopes of human immunodeficiency virus regulatory proteins tat, nef, and rev are expressed in normal human tissue

NARCIS (Netherlands)

Parmentier, H. K.; van Wichen, D. F.; Meyling, F. H.; Goudsmit, J.; Schuurman, H. J.

1992-01-01

The expression of regulatory proteins tat, rev, and nef of human immunodeficiency virus type-1 (HIV-1) and tat of HIV-2 was studied in frozen sections of lymph nodes from HIV-1-infected individuals, and various tissues from uninfected persons. In HIV-1-positive lymph nodes, monoclonal antibodies to

Inhibition of Non Canonical HIV-1 Tat Secretion Through the Cellular Na+,K+-ATPase Blocks HIV-1 Infection

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Silvia Agostini

2017-07-01

Full Text Available Besides its essential role in the activation of HIV-1 gene expression, the viral Tat protein has the unusual property of trafficking in and out of cells. In contrast to Tat internalization, the mechanism involved in extracellular Tat release has so far remained elusive. Here we show that Tat secretion occurs through a Golgi-independent pathway requiring binding of Tat with three short, non-consecutive intracytoplasmic loops at the C-terminus of the cellular Na+,K+-ATPase pump alpha subunit. Ouabain, a pump inhibitor, blocked this interaction and prevented Tat secretion; virions produced in the presence of this drug were less infectious, consistent the capacity of virion-associated Tat to increase HIV-1 infectivity. Treatment of CD4+ T-cells with short peptides corresponding to the Tat-binding regions of the pump alpha subunit impaired extracellular Tat release and blocked HIV-1 replication. Thus, non canonical, extracellular Tat secretion is essential for viral infectivity.

Trans-activation of the JC virus late promoter by the tat protein of type 1 human immunodeficiency virus in glial cells

International Nuclear Information System (INIS)

Tada, Hiroomi; Lashgari, M.; Amini, S.; Khalili, K.; Rappaport, J.; Wong-Staal, F.

1990-01-01

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system caused by the JC virus (JCV), a human papovavirus. PML is a relatively rare disease seen predominantly in immunocompromised individuals and is a frequent complication observed in AIDS patients. The significantly higher incidence of PML in AIDS patients than in other immunosuppressive disorders has suggested that the presence of human immunodeficiency virus type 1 (HIV-1) in the brain may directly or indirectly contribute to the pathogenesis of this disease. In the present study the authors have examined the expression of the JCV genome in both glial and non-glial cells in the presence of HIV-1 regulatory proteins. They find that the HIV-1-encoded trans-regulatory protein tat increases the basal activity of the JCV late promoter, JCV L , in glial cells. They conclude that the presence of the HIV-1-encoded tat protein may positively affect the JCV lytic cycle in glial cells by stimulating JCV gene expression. The results suggest a mechanism for the relatively high incidence of PML in AIDS patients than in other immunosuppressive disorders. Furthermore, the findings indicate that the HIV-1 regulatory protein tat may stimulate other viral and perhaps cellular promoters, in addition to its own

Interaction between HIV-1 Tat and DNA-PKcs modulates HIV transcription and class switch recombination.

Science.gov (United States)

Zhang, Shi-Meng; Zhang, He; Yang, Tian-Yi; Ying, Tian-Yi; Yang, Pei-Xiang; Liu, Xiao-Dan; Tang, Sheng-Jian; Zhou, Ping-Kun

2014-01-01

HIV-1 tat targets a variety of host cell proteins to facilitate viral transcription and disrupts host cellular immunity by inducing lymphocyte apoptosis, but whether it influences humoral immunity remains unclear. Previously, our group demonstrated that tat depresses expression of DNA-PKcs, a critical component of the non-homologous end joining pathway (NHEJ) of DNA double-strand breaks repair, immunoglobulin class switch recombination (CSR) and V(D)J recombination, and sensitizes cells to ionizing radiation. In this study, we demonstrated that HIV-1 Tat down-regulates DNA-PKcs expression by directly binding to the core promoter sequence. In addition, Tat interacts with and activates the kinase activity of DNA-PKcs in a dose-dependent and DNA independent manner. Furthermore, Tat inhibits class switch recombination (CSR) at low concentrations (≤ 4 µg/ml) and stimulates CSR at high concentrations (≥ 8 µg/ml). On the other hand, low protein level and high kinase activity of DNA-PKcs promotes HIV-1 transcription, while high protein level and low kinase activity inhibit HIV-1 transcription. Co-immunoprecipitation results revealed that DNA-PKcs forms a large complex comprised of Cyclin T1, CDK9 and Tat via direct interacting with CDK9 and Tat but not Cyclin T1. Taken together, our results provide new clues that Tat regulates host humoral immunity via both transcriptional depression and kinase activation of DNA-PKcs. We also raise the possibility that inhibitors and interventions directed towards DNA-PKcs may inhibit HIV-1 transcription in AIDS patients.

Improved intracellular delivery of glucocerebrosidase mediated by the HIV-1 TAT protein transduction domain

International Nuclear Information System (INIS)

Lee, Kyun Oh; Luu, Nga; Kaneski, Christine R.; Schiffmann, Raphael; Brady, Roscoe O.; Murray, Gary J.

2005-01-01

Enzyme replacement therapy (ERT) for Gaucher disease designed to target glucocerebrosidase (GC) to macrophages via mannose-specific endocytosis is very effective in reversing hepatosplenomegaly, and normalizing hematologic parameters but is less effective in improving bone and lung involvement and ineffective in brain. Recombinant GCs containing an in-frame fusion to the HIV-1 trans-activator protein transduction domain (TAT) were expressed in eukaryotic cells in order to obtain active, normally glycosylated GC fusion proteins for enzyme uptake studies. Despite the absence of mannose-specific endocytic receptors on the plasma membranes of various fibroblasts, the recombinant GCs with C-terminal TAT fusions were readily internalized by these cells. Immunofluorescent confocal microscopy demonstrated the recombinant TAT-fusion proteins with a mixed endosomal and lysosomal localization. Thus, TAT-modified GCs represent a novel strategy for a new generation of therapeutic enzymes for ERT for Gaucher disease

Development of Tat-Conjugated Dendrimer for Transdermal DNA Vaccine Delivery.

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Bahadoran, Azadeh; Moeini, Hassan; Bejo, Mohd Hair; Hussein, Mohd Zobir; Omar, Abdul Rahman

In order to enhance cellular uptake and to facilitate transdermal delivery of DNA vaccine, polyamidoamine (PAMAM) dendrimers conjugated with HIV transactivator of transcription (TAT) was developed. First, the plasmid DNA (pIRES-H5/GFP) nanoparticle was formulated using PAMAM dendrimer and TAT peptide and then characterized for surface charge, particle size, DNA encapsulation and protection of the pIRES-H5/GFP DNA plasmid to enzymatic digestion. Subsequently, the potency of the TAT-conjugated dendrimer for gene delivery was evaluated through in vitro transfection into Vero cells followed by gene expression analysis including western blotting, fluorescent microscopy and PCR. The effect of the TAT peptide on cellular uptake of DNA vaccine was studied by qRT-PCR and flow cytometry. Finally, the ability of TAT-conjugated PAMAM dendrimer for transdermal delivery of the DNA plasmid was assessed through artificial membranes followed by qRT-PCR and flow cytometry. TAT-conjugated PAMAM dendrimer showed the ability to form a compact and nanometre-sized polyplexes with the plasmid DNA, having the size range of 105 to 115 nm and a positive charge of +42 to +45 mV over the N/P ratio of 6:1(+/-).  In vitro transfection analysis into Vero cells confirms the high potency of TAT-conjugated PAMAM dendrimer to enhance the cellular uptake of DNA vaccine.  The permeability value assay through artificial membranes reveals that TAT-conjugated PAMAM has more capacity for transdermal delivery of the DNA compared to unmodified PAMAM dendrimer (Pdendrimer is a promising non-viral vector for transdermal use.This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

Inhibition of both HIV-1 reverse transcription and gene expression by a cyclic peptide that binds the Tat-transactivating response element (TAR RNA.

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Matthew S Lalonde

2011-05-01

Full Text Available The RNA response element TAR plays a critical role in HIV replication by providing a binding site for the recruitment of the viral transactivator protein Tat. Using a structure-guided approach, we have developed a series of conformationally-constrained cyclic peptides that act as structural mimics of the Tat RNA binding region and block Tat-TAR interactions at nanomolar concentrations in vitro. Here we show that these compounds block Tat-dependent transcription in cell-free systems and in cell-based reporter assays. The compounds are also cell permeable, have low toxicity, and inhibit replication of diverse HIV-1 strains, including both CXCR4-tropic and CCR5-tropic primary HIV-1 isolates of the divergent subtypes A, B, C, D and CRF01_AE. In human peripheral blood mononuclear cells, the cyclic peptidomimetic L50 exhibited an IC(50 ∼250 nM. Surprisingly, inhibition of LTR-driven HIV-1 transcription could not account for the full antiviral activity. Timed drug-addition experiments revealed that L-50 has a bi-phasic inhibition curve with the first phase occurring after HIV-1 entry into the host cell and during the initiation of HIV-1 reverse transcription. The second phase coincides with inhibition of HIV-1 transcription. Reconstituted reverse transcription assays confirm that HIV-1 (- strand strong stop DNA synthesis is blocked by L50-TAR RNA interactions in-vitro. These findings are consistent with genetic evidence that TAR plays critical roles both during reverse transcription and during HIV gene expression. Our results suggest that antiviral drugs targeting TAR RNA might be highly effective due to a dual inhibitory mechanism.

Functional analysis of human aromatic amino acid transporter MCT10/TAT1 using the yeast Saccharomyces cerevisiae.

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Uemura, Satoshi; Mochizuki, Takahiro; Kurosaka, Goyu; Hashimoto, Takanori; Masukawa, Yuki; Abe, Fumiyoshi

2017-10-01

Tryptophan is an essential amino acid in humans and an important serotonin and melatonin precursor. Monocarboxylate transporter MCT10 is a member of the SLC16A family proteins that mediates low-affinity tryptophan transport across basolateral membranes of kidney, small intestine, and liver epithelial cells, although the precise transport mechanism remains unclear. Here we developed a simple functional assay to analyze tryptophan transport by human MCT10 using a deletion mutant for the high-affinity tryptophan permease Tat2 in Saccharomyces cerevisiae. tat2Δtrp1 cells are defective in growth in YPD medium because tyrosine present in the medium competes for the low-affinity tryptophan permease Tat1 with tryptophan. MCT10 appeared to allow growth of tat2Δtrp1 cells in YPD medium, and accumulate in cells deficient for Rsp5 ubiquitin ligase. These results suggest that MCT10 is functional in yeast, and is subject to ubiquitin-dependent quality control. Whereas growth of Tat2-expressing cells was significantly impaired by neutral pH, that of MCT10-expressing cells was nearly unaffected. This property is consistent with the transport mechanism of MCT10 via facilitated diffusion without a need for pH gradient across the plasma membrane. Single-nucleotide polymorphisms (SNPs) are known to occur in the human MCT10 coding region. Among eight SNP amino acid changes in MCT10, the N81K mutation completely abrogated tryptophan import without any abnormalities in the expression or localization. In the MCT10 modeled structure, N81 appeared to protrude into the putative trajectory of tryptophan. Plasma membrane localization of MCT10 and the variant proteins was also verified in human embryonic kidney 293T cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Tat-antioxidant 1 protects against stress-induced hippocampal HT-22 cells death and attenuate ischaemic insult in animal model.

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Kim, So Mi; Hwang, In Koo; Yoo, Dae Young; Eum, Won Sik; Kim, Dae Won; Shin, Min Jea; Ahn, Eun Hee; Jo, Hyo Sang; Ryu, Eun Ji; Yong, Ji In; Cho, Sung-Woo; Kwon, Oh-Shin; Lee, Keun Wook; Cho, Yoon Shin; Han, Kyu Hyung; Park, Jinseu; Choi, Soo Young

2015-06-01

Oxidative stress-induced reactive oxygen species (ROS) are responsible for various neuronal diseases. Antioxidant 1 (Atox1) regulates copper homoeostasis and promotes cellular antioxidant defence against toxins generated by ROS. The roles of Atox1 protein in ischaemia, however, remain unclear. In this study, we generated a protein transduction domain fused Tat-Atox1 and examined the roles of Tat-Atox1 in oxidative stress-induced hippocampal HT-22 cell death and an ischaemic injury animal model. Tat-Atox1 effectively transduced into HT-22 cells and it protected cells against the effects of hydrogen peroxide (H2O2)-induced toxicity including increasing of ROS levels and DNA fragmentation. At the same time, Tat-Atox1 regulated cellular survival signalling such as p53, Bad/Bcl-2, Akt and mitogen-activate protein kinases (MAPKs). In the animal ischaemia model, transduced Tat-Atox1 protected against neuronal cell death in the hippocampal CA1 region. In addition, Tat-Atox1 significantly decreased the activation of astrocytes and microglia as well as lipid peroxidation in the CA1 region after ischaemic insult. Taken together, these results indicate that transduced Tat-Atox1 protects against oxidative stress-induced HT-22 cell death and against neuronal damage in animal ischaemia model. Therefore, we suggest that Tat-Atox1 has potential as a therapeutic agent for the treatment of oxidative stress-induced ischaemic damage. © 2015 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Structural basis for TatA oligomerization: an NMR study of Escherichia coli TatA dimeric structure.

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Yi Zhang

Full Text Available Many proteins are transported across lipid membranes by protein translocation systems in living cells. The twin-arginine transport (Tat system identified in bacteria and plant chloroplasts is a unique system that transports proteins across membranes in their fully-folded states. Up to date, the detailed molecular mechanism of this process remains largely unclear. The Escherichia coli Tat system consists of three essential transmembrane proteins: TatA, TatB and TatC. Among them, TatB and TatC form a tight complex and function in substrate recognition. The major component TatA contains a single transmembrane helix followed by an amphipathic helix, and is suggested to form the translocation pore via self-oligomerization. Since the TatA oligomer has to accommodate substrate proteins of various sizes and shapes, the process of its assembly stands essential for understanding the translocation mechanism. A structure model of TatA oligomer was recently proposed based on NMR and EPR observations, revealing contacts between the transmembrane helices from adjacent subunits. Herein we report the construction and stabilization of a dimeric TatA, as well as the structure determination by solution NMR spectroscopy. In addition to more extensive inter-subunit contacts between the transmembrane helices, we were also able to observe interactions between neighbouring amphipathic helices. The side-by-side packing of the amphipathic helices extends the solvent-exposed hydrophilic surface of the protein, which might be favourable for interactions with substrate proteins. The dimeric TatA structure offers more detailed information of TatA oligomeric interface and provides new insights on Tat translocation mechanism.

Ex vivo expansion of hematopoietic stem cell by fusion protein TAT-Zfx

International Nuclear Information System (INIS)

Xu Chong; Zhang Yanbing; Jiang Hua

2009-01-01

The relative inability of hemopoietic stem cells (HSCs) to reproduce themselves (self-renew) ex vivo imposes substantial limitations on the current use of HSC transplantation. Recently, the transcription factor Zfx has been demonstrated that played an important in controlling the self-renewal of hematopoietic stem cells. Here, we reported that Zfx could enable high-level expansion of HSCs in vitro, by combination of protein transduction domain, TAT. Furthermore, we also demonstrated that expanded HSCs population retains their normal in vivo potential of pluripotency. It is thus that TAT-Zfx has the potential to expand HSCs significantly in vitro, and will have enormous clinical potentials.

Novel PI3K/Akt Inhibitors Screened by the Cytoprotective Function of Human Immunodeficiency Virus Type 1 Tat

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Kim, Dong-Hyun; Kim, Baek

2011-01-01

The PI3K/Akt pathway regulates various stress-related cellular responses such as cell survival, cell proliferation, metabolism and protein synthesis. Many cancer cell types display the activation of this pathway, and compounds inhibiting this cell survival pathway have been extensively evaluated as anti-cancer agents. In addition to cancers, several human viruses, such as HTLV, HPV, HCV and HIV-1, also modulate this pathway, presumably in order to extend the life span of the infected target cells for productive viral replication. The expression of HIV-1 Tat protein exhibited the cytoprotective effect in macrophages and a human microglial cell line by inhibiting the negative regulator of this pathway, PTEN. This cytoprotective effect of HIV-1 appears to contribute to the long-term survival and persistent HIV-1 production in human macrophage reservoirs. In this study we exploited the PI3K/Akt dependent cytoprotective effect of Tat-expressing CHME5 cells. We screened a collection of compounds known to modulate inflammation, and identified three novel compounds: Lancemaside A, Compound K and Arctigenin that abolished the cytoprotective phenotype of Tat-expressing CHME5 cells. All three compounds antagonized the kinase activity of Akt. Further detailed signaling studies revealed that each of these three compounds targeted different steps of the PI3K/Akt pathway. Arctigenin regulates the upstream PI3K enzyme from converting PIP2 to PIP3. Lancemaside A1 inhibited the movement of Akt to the plasma membrane, a critical step for Akt activation. Compound K inhibited Akt phosphorylation. This study supports that Tat-expressing CHME5 cells are an effective model system for screening novel PI3K/Akt inhibitors. PMID:21765914

Novel PI3K/Akt inhibitors screened by the cytoprotective function of human immunodeficiency virus type 1 Tat.

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Yuri Kim

Full Text Available The PI3K/Akt pathway regulates various stress-related cellular responses such as cell survival, cell proliferation, metabolism and protein synthesis. Many cancer cell types display the activation of this pathway, and compounds inhibiting this cell survival pathway have been extensively evaluated as anti-cancer agents. In addition to cancers, several human viruses, such as HTLV, HPV, HCV and HIV-1, also modulate this pathway, presumably in order to extend the life span of the infected target cells for productive viral replication. The expression of HIV-1 Tat protein exhibited the cytoprotective effect in macrophages and a human microglial cell line by inhibiting the negative regulator of this pathway, PTEN. This cytoprotective effect of HIV-1 appears to contribute to the long-term survival and persistent HIV-1 production in human macrophage reservoirs. In this study we exploited the PI3K/Akt dependent cytoprotective effect of Tat-expressing CHME5 cells. We screened a collection of compounds known to modulate inflammation, and identified three novel compounds: Lancemaside A, Compound K and Arctigenin that abolished the cytoprotective phenotype of Tat-expressing CHME5 cells. All three compounds antagonized the kinase activity of Akt. Further detailed signaling studies revealed that each of these three compounds targeted different steps of the PI3K/Akt pathway. Arctigenin regulates the upstream PI3K enzyme from converting PIP2 to PIP3. Lancemaside A1 inhibited the movement of Akt to the plasma membrane, a critical step for Akt activation. Compound K inhibited Akt phosphorylation. This study supports that Tat-expressing CHME5 cells are an effective model system for screening novel PI3K/Akt inhibitors.

Effect of the peptide Tat(49-57) on the bio-distribution and similar radiopharmaceuticals dosimetry of the bombesin; Efecto del peptido TAT(49-57) sobre la biodistribucion y dosimetria de radiofarmacos analogos de la bombesina

Energy Technology Data Exchange (ETDEWEB)

Santos C, C. L.

2011-07-01

The gastrin-releasing peptide receptor (GRP-r) is over-expressed in prostate and breast cancer. {sup 99m}Tc-Bombesin ({sup 99m}Tc-Bn) has been reported as a radiopharmaceutical with specific cell GRP-r binding. The HIV Tat(49-57)-derived peptide has been used to deliver a large variety of molecules to cell nuclei. New hybrid radiopharmaceuticals of type {sup 99m}Tc-N{sub 2}S{sub 2}-Tat(49-57)-Lys{sup 3}-Bn ({sup 99m}Tc-Tat-Bn) and {sup 188}Re-N{sub 2}S{sub 2}-Tat(49-57)-Lys{sup 3}-Bn ({sup 188}Re-Tat-Bn), would increase cell uptake and internalized in cancer cell nuclei could act as an effective system of targeted radiotherapy using Auger and internal conversion (I C) electron emissions near DNA. The aim of this research was to prepare and assess in vitro and in vivo uptake kinetics in cancer cells of {sup 99m}Tc/{sup 188}Re-Tat-Bn and the in vitro nucleus and cytoplasm internalization kinetics in GRP receptor-positive cancer cells as well as to evaluate the subcellular-level radiation absorbed dose associated with the observed effect on cancer cell DNA proliferation. Structures of N{sub 2}S{sub 2}-Tat-Bn and Tc/Re(O)N{sub 2}S{sub 2}-Tat-Bn were calculated by an Mm procedure. {sup 99m}Tc-Tat-Bn and {sup 188}Re-Tat-Bn were synthesized and stability studies carried out by HPLC and I TLC-Sg analyses in serum and cysteine solutions. In vitro internalization was tested using human prostate cancer Pc 3 cells and breast carcinoma cell lines MDA-Mb 231 and MCF 7. Nuclei from cells were isolated using a nuclear extraction kit. Total disintegrations in each subcellular compartment were calculated by integration of experimental time activity kinetic curves. Nucleus internalization was corroborated by con focal microscopy images using immunofluorescent labelled Tat-Bn. Biodistribution was determined in Pc 3 tumor-bearing nude mice. The Penelope code was used to simulate and calculate the absorbed dose by contribution of {beta}, Auger and I C electrons in the cytoplasm and

Progesterone protects normative anxiety-like responding among ovariectomized female mice that conditionally express the HIV-1 regulatory protein, Tat, in the CNS.

Science.gov (United States)

Paris, Jason J; Fenwick, Jason; McLaughlin, Jay P

2014-05-01

Increased anxiety is co-morbid with human immunodeficiency virus (HIV) infection. Actions of the neurotoxic HIV-1 regulatory protein, Tat, may contribute to affective dysfunction. We hypothesized that Tat expression would increase anxiety-like behavior of female GT-tg bigenic mice that express HIV-1 Tat protein in the brain in a doxycycline-dependent manner. Furthermore, given reports that HIV-induced anxiety may occur at lower rates among women, and that the neurotoxic effects of Tat are ameliorated by sex steroids in vitro, we hypothesized that 17β-estradiol and/or progesterone would ameliorate Tat-induced anxiety-like effects. Among naturally-cycling proestrous and diestrous mice, Tat-induction via 7days of doxycycline treatment significantly increased anxiety-like responding in an open field, elevated plus maze and a marble-burying task, compared to treatment with saline. Proestrous mice demonstrated less anxiety-like behavior than diestrous mice in the open field and elevated plus maze, but these effects did not significantly interact with Tat-induction. Among ovariectomized mice, doxycycline-induced Tat protein significantly increased anxiety-like behavior in an elevated plus maze and a marble burying task compared to saline-treated mice, but not an open field (where anxiety-like responding was already maximal). Co-administration of progesterone (4mg/kg), but not 17β-estradiol (0.09mg/kg), with doxycycline significantly ameliorated anxiety-like responding in the elevated plus maze and marble burying tasks. When administered together, 17β-estradiol partially antagonized the protective effects of progesterone on Tat-induced anxiety-like behavior. These findings support evidence of steroid-protection over HIV-1 proteins, and extend them by demonstrating the protective capacity of progesterone on Tat-induced anxiety-like behavior of ovariectomized female mice. Copyright © 2014 Elsevier Inc. All rights reserved.

Modulation of microtubule assembly by the HIV-1 Tat protein is strongly dependent on zinc binding to Tat

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Muller Sylviane

2008-07-01

Full Text Available Abstract Background During HIV-1 infection, the Tat protein plays a key role by transactivating the transcription of the HIV-1 proviral DNA. In addition, Tat induces apoptosis of non-infected T lymphocytes, leading to a massive loss of immune competence. This apoptosis is notably mediated by the interaction of Tat with microtubules, which are dynamic components essential for cell structure and division. Tat binds two Zn2+ ions through its conserved cysteine-rich region in vitro, but the role of zinc in the structure and properties of Tat is still controversial. Results To investigate the role of zinc, we first characterized Tat apo- and holo-forms by fluorescence correlation spectroscopy and time-resolved fluorescence spectroscopy. Both of the Tat forms are monomeric and poorly folded but differ by local conformational changes in the vicinity of the cysteine-rich region. The interaction of the two Tat forms with tubulin dimers and microtubules was monitored by analytical ultracentrifugation, turbidity measurements and electron microscopy. At 20°C, both of the Tat forms bind tubulin dimers, but only the holo-Tat was found to form discrete complexes. At 37°C, both forms promoted the nucleation and increased the elongation rates of tubulin assembly. However, only the holo-Tat increased the amount of microtubules, decreased the tubulin critical concentration, and stabilized the microtubules. In contrast, apo-Tat induced a large amount of tubulin aggregates. Conclusion Our data suggest that holo-Tat corresponds to the active form, responsible for the Tat-mediated apoptosis.

Tat-CBR1 inhibits inflammatory responses through the suppressions of NF-κB and MAPK activation in macrophages and TPA-induced ear edema in mice

Energy Technology Data Exchange (ETDEWEB)

Kim, Young Nam [Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chunchon 200-702 (Korea, Republic of); Kim, Dae Won [Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Kangnung-Wonju National University, Kangneung 210-702 (Korea, Republic of); Jo, Hyo Sang; Shin, Min Jea; Ahn, Eun Hee; Ryu, Eun Ji; Yong, Ji In; Cha, Hyun Ju; Kim, Sang Jin; Yeo, Hyeon Ji; Youn, Jong Kyu; Hwang, Jae Hyeok [Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chunchon 200-702 (Korea, Republic of); Jeong, Ji-Heon; Kim, Duk-Soo [Department of Anatomy, College of Medicine, Soonchunhyang University, Cheonan-Si 330-090 (Korea, Republic of); Cho, Sung-Woo [Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul 138-736 (Korea, Republic of); Park, Jinseu [Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chunchon 200-702 (Korea, Republic of); Eum, Won Sik, E-mail: wseum@hallym.ac.kr [Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chunchon 200-702 (Korea, Republic of); Choi, Soo Young, E-mail: sychoi@hallym.ac.kr [Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chunchon 200-702 (Korea, Republic of)

2015-07-15

Human carbonyl reductase 1 (CBR1) plays a crucial role in cell survival and protects against oxidative stress response. However, its anti-inflammatory effects are not yet clearly understood. In this study, we examined whether CBR1 protects against inflammatory responses in macrophages and mice using a Tat-CBR1 protein which is able to penetrate into cells. The results revealed that purified Tat-CBR1 protein efficiently transduced into Raw 264.7 cells and inhibited lipopolysaccharide (LPS)-induced cyclooxygenase-2 (COX-2), nitric oxide (NO) and prostaglandin E{sub 2} (PGE{sub 2}) expression levels. In addition, Tat-CBR1 protein leads to decreased pro-inflammatory cytokine expression through suppression of nuclear transcription factor-kappaB (NF-κB) and mitogen activated protein kinase (MAPK) activation. Furthermore, Tat-CBR1 protein inhibited inflammatory responses in 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced skin inflammation when applied topically. These findings indicate that Tat-CBR1 protein has anti-inflammatory properties in vitro and in vivo through inhibition of NF-κB and MAPK activation, suggesting that Tat-CBR1 protein may have potential as a therapeutic agent against inflammatory diseases. - Highlights: • Transduced Tat-CBR1 reduces LPS-induced inflammatory mediators and cytokines. • Tat-CBR1 inhibits MAPK and NF-κB activation. • Tat-CBR1 ameliorates inflammation response in vitro and in vivo. • Tat-CBR1 may be useful as potential therapeutic agent for inflammation.

Recombinant TAT-BMI-1 fusion protein induces ex vivo expansion of human umbilical cord blood-derived hematopoietic stem cells.

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Codispoti, Bruna; Rinaldo, Nicola; Chiarella, Emanuela; Lupia, Michela; Spoleti, Cristina Barbara; Marafioti, Maria Grazia; Aloisio, Annamaria; Scicchitano, Stefania; Giordano, Marco; Nappo, Giovanna; Lucchino, Valeria; Moore, Malcolm A S; Zhou, Pengbo; Mesuraca, Maria; Bond, Heather Mandy; Morrone, Giovanni

2017-07-04

Transplantation of hematopoietic stem cells (HSCs) is a well-established therapeutic approach for numerous disorders. HSCs are typically derived from bone marrow or peripheral blood after cytokine-induced mobilization. Umbilical cord blood (CB) represents an appealing alternative HSC source, but the small amounts of the individual CB units have limited its applications. The availability of strategies for safe ex vivo expansion of CB-derived HSCs (CB-HSCs) may allow to extend the use of these cells in adult patients and to avoid the risk of insufficient engraftment or delayed hematopoietic recovery.Here we describe a system for the ex vivo expansion of CB-HSCs based on their transient exposure to a recombinant TAT-BMI-1 chimeric protein. BMI-1 belongs to the Polycomb family of epigenetic modifiers and is recognized as a central regulator of HSC self-renewal. Recombinant TAT-BMI-1 produced in bacteria was able to enter the target cells via the HIV TAT-derived protein transduction peptide covalently attached to BMI-1, and conserved its biological activity. Treatment of CB-CD34+ cells for 3 days with repeated addition of 10 nM purified TAT-BMI-1 significantly enhanced total cell expansion as well as that of primitive hematopoietic progenitors in culture. Importantly, TAT-BMI-1-treated CB-CD34+ cells displayed a consistently higher rate of multi-lineage long-term repopulating activity in primary and secondary xenotransplants in immunocompromised mice. Thus, recombinant TAT-BMI-1 may represent a novel, effective reagent for ex vivo expansion of CB-HSC for therapeutic purposes.

Effect of the peptide Tat(49-57) on the bio-distribution and similar radiopharmaceuticals dosimetry of the bombesin

International Nuclear Information System (INIS)

Santos C, C. L.

2011-01-01

The gastrin-releasing peptide receptor (GRP-r) is over-expressed in prostate and breast cancer. 99m Tc-Bombesin ( 99m Tc-Bn) has been reported as a radiopharmaceutical with specific cell GRP-r binding. The HIV Tat(49-57)-derived peptide has been used to deliver a large variety of molecules to cell nuclei. New hybrid radiopharmaceuticals of type 99m Tc-N 2 S 2 -Tat(49-57)-Lys 3 -Bn ( 99m Tc-Tat-Bn) and 188 Re-N 2 S 2 -Tat(49-57)-Lys 3 -Bn ( 188 Re-Tat-Bn), would increase cell uptake and internalized in cancer cell nuclei could act as an effective system of targeted radiotherapy using Auger and internal conversion (I C) electron emissions near DNA. The aim of this research was to prepare and assess in vitro and in vivo uptake kinetics in cancer cells of 99m Tc/ 188 Re-Tat-Bn and the in vitro nucleus and cytoplasm internalization kinetics in GRP receptor-positive cancer cells as well as to evaluate the subcellular-level radiation absorbed dose associated with the observed effect on cancer cell DNA proliferation. Structures of N 2 S 2 -Tat-Bn and Tc/Re(O)N 2 S 2 -Tat-Bn were calculated by an Mm procedure. 99m Tc-Tat-Bn and 188 Re-Tat-Bn were synthesized and stability studies carried out by HPLC and I TLC-Sg analyses in serum and cysteine solutions. In vitro internalization was tested using human prostate cancer Pc 3 cells and breast carcinoma cell lines MDA-Mb 231 and MCF 7. Nuclei from cells were isolated using a nuclear extraction kit. Total disintegrations in each subcellular compartment were calculated by integration of experimental time activity kinetic curves. Nucleus internalization was corroborated by con focal microscopy images using immunofluorescent labelled Tat-Bn. Biodistribution was determined in Pc 3 tumor-bearing nude mice. The Penelope code was used to simulate and calculate the absorbed dose by contribution of β, Auger and I C electrons in the cytoplasm and nucleus using geometric models built from immunofluorescent cell images. A cell proliferation

HIV-1 TAT protein enhances sensitization to methamphetamine by affecting dopaminergic function.

Science.gov (United States)

Kesby, James P; Najera, Julia A; Romoli, Benedetto; Fang, Yiding; Basova, Liana; Birmingham, Amanda; Marcondes, Maria Cecilia G; Dulcis, Davide; Semenova, Svetlana

2017-10-01

Methamphetamine abuse is common among humans with immunodeficiency virus (HIV). The HIV-1 regulatory protein TAT induces dysfunction of mesolimbic dopaminergic systems which may result in impaired reward processes and contribute to methamphetamine abuse. These studies investigated the impact of TAT expression on methamphetamine-induced locomotor sensitization, underlying changes in dopamine function and adenosine receptors in mesolimbic brain areas and neuroinflammation (microgliosis). Transgenic mice with doxycycline-induced TAT protein expression in the brain were tested for locomotor activity in response to repeated methamphetamine injections and methamphetamine challenge after a 7-day abstinence period. Dopamine function in the nucleus accumbens (Acb) was determined using high performance liquid chromatography. Expression of dopamine and/or adenosine A receptors (ADORA) in the Acb and caudate putamen (CPu) was assessed using RT-PCR and immunohistochemistry analyses. Microarrays with pathway analyses assessed dopamine and adenosine signaling in the CPu. Activity-dependent neurotransmitter switching of a reserve pool of non-dopaminergic neurons to a dopaminergic phenotype in the ventral tegmental area (VTA) was determined by immunohistochemistry and quantified with stereology. TAT expression enhanced methamphetamine-induced sensitization. TAT expression alone decreased striatal dopamine (D1, D2, D4, D5) and ADORA1A receptor expression, while increasing ADORA2A receptors expression. Moreover, TAT expression combined with methamphetamine exposure was associated with increased adenosine A receptors (ADORA1A) expression and increased recruitment of dopamine neurons in the VTA. TAT expression and methamphetamine exposure induced microglia activation with the largest effect after combined exposure. Our findings suggest that dopamine-adenosine receptor interactions and reserve pool neuronal recruitment may represent potential targets to develop new treatments for

PDGF-mediated protection of SH-SY5Y cells against Tat toxin involves regulation of extracellular glutamate and intracellular calcium

International Nuclear Information System (INIS)

Zhu Xuhui; Yao Honghong; Peng Fuwang; Callen, Shannon; Buch, Shilpa

2009-01-01

The human immunodeficiency virus (HIV-1) protein Tat has been implicated in mediating neuronal apoptosis, one of the hallmark features of HIV-associated dementia (HAD). Mitigation of the toxic effects of Tat could thus be a potential mechanism for reducing HIV toxicity in the brain. In this study we demonstrated that Tat-induced neurotoxicity was abolished by NMDA antagonist-MK801, suggesting the role of glutamate in this process. Furthermore, we also found that pretreatment of SH-SY5Y cells with PDGF exerted protection against Tat toxicity by decreasing extracellular glutamate levels. We also demonstrated that extracellular calcium chelator EGTA was able to abolish PDGF-mediated neuroprotection, thereby underscoring the role of calcium signaling in PDGF-mediated neuroprotection. We also showed that Erk signaling pathway was critical for PDGF-mediated protection of cells. Additionally, blocking calcium entry with EGTA resulted in suppression of PDGF-induced Erk activation. These findings thus underscore the role of PDGF-mediated calcium signaling and Erk phosphorylation in the protection of cells against HIV Tat toxicity.

HIV-1 tat promotes integrin-mediated HIV transmission to dendritic cells by binding Env spikes and competes neutralization by anti-HIV antibodies.

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Paolo Monini

Full Text Available Use of Env in HIV vaccine development has been disappointing. Here we show that, in the presence of a biologically active Tat subunit vaccine, a trimeric Env protein prevents in monkeys virus spread from the portal of entry to regional lymph nodes. This appears to be due to specific interactions between Tat and Env spikes that form a novel virus entry complex favoring R5 or X4 virus entry and productive infection of dendritic cells (DCs via an integrin-mediated pathway. These Tat effects do not require Tat-transactivation activity and are blocked by anti-integrin antibodies (Abs. Productive DC infection promoted by Tat is associated with a highly efficient virus transmission to T cells. In the Tat/Env complex the cysteine-rich region of Tat engages the Env V3 loop, whereas the Tat RGD sequence remains free and directs the virus to integrins present on DCs. V2 loop deletion, which unshields the CCR5 binding region of Env, increases Tat/Env complex stability. Of note, binding of Tat to Env abolishes neutralization of Env entry or infection of DCs by anti-HIV sera lacking anti-Tat Abs, which are seldom present in natural infection. This is reversed, and neutralization further enhanced, by HIV sera containing anti-Tat Abs such as those from asymptomatic or Tat-vaccinated patients, or by sera from the Tat/Env vaccinated monkeys. Thus, both anti-Tat and anti-Env Abs are required for efficient HIV neutralization. These data suggest that the Tat/Env interaction increases HIV acquisition and spreading, as a mechanism evolved by the virus to escape anti-Env neutralizing Abs. This may explain the low effectiveness of Env-based vaccines, which are also unlikely to elicit Abs against new Env epitopes exposed by the Tat/Env interaction. As Tat also binds Envs from different clades, new vaccine strategies should exploit the Tat/Env interaction for both preventative and therapeutic interventions.

TAT-Gap19 and Carbenoxolone Alleviate Liver Fibrosis in Mice

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Sara Crespo Yanguas

2018-03-01

Full Text Available Although a plethora of signaling pathways are known to drive the activation of hepatic stellate cells in liver fibrosis, the involvement of connexin-based communication in this process remains elusive. Connexin43 expression is enhanced in activated hepatic stellate cells and constitutes the molecular building stone of hemichannels and gap junctions. While gap junctions support intercellular communication, and hence the maintenance of liver homeostasis, hemichannels provide a circuit for extracellular communication and are typically opened by pathological stimuli, such as oxidative stress and inflammation. The present study was set up to investigate the effects of inhibition of connexin43-based hemichannels and gap junctions on liver fibrosis in mice. Liver fibrosis was induced by administration of thioacetamide to Balb/c mice for eight weeks. Thereafter, mice were treated for two weeks with TAT-Gap19, a specific connexin43 hemichannel inhibitor, or carbenoxolone, a general hemichannel and gap junction inhibitor. Subsequently, histopathological analysis was performed and markers of hepatic damage and functionality, oxidative stress, hepatic stellate cell activation and inflammation were evaluated. Connexin43 hemichannel specificity of TAT-Gap19 was confirmed in vitro by fluorescence recovery after photobleaching analysis and the measurement of extracellular release of adenosine-5′-triphosphate. Upon administration to animals, both TAT-Gap19 and carbenoxolone lowered the degree of liver fibrosis accompanied by superoxide dismutase overactivation and reduced production of inflammatory proteins, respectively. These results support a role of connexin-based signaling in the resolution of liver fibrosis, and simultaneously demonstrate the therapeutic potential of TAT-Gap19 and carbenoxolone in the treatment of this type of chronic liver disease.

Safety and immunogenicity of HIV-1 Tat toxoid in immunocompromised HIV-1-infected patients.

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Gringeri, A; Santagostino, E; Muça-Perja, M; Mannucci, P M; Zagury, J F; Bizzini, B; Lachgar, A; Carcagno, M; Rappaport, J; Criscuolo, M; Blattner, W; Burny, A; Gallo, R C; Zagury, D

1998-01-01

To antagonize the deleterious effects of the HIV-1 toxin extracellular Tat on uninfected immune cells, we developed a new strategy of anti-HIV-1 vaccine using an inactivated but immunogenic Tat (Tat toxoid). Tat toxoid has been assayed for safety and immunogenicity in seropositive patients. The phase I vaccine clinical trial testing Tat toxoid preparation in Seppic Isa 51 oil adjuvant was performed on 14 HIV-1-infected asymptomatic although biologically immunocompromised individuals (500-200 CD4+ cells/mm3). Following as many as 8 injections, no clinical defects were observed. All patients exhibited an antibody (Ab) response to Tat, and some had cell-mediated immunity (CMI) as evaluated by skin test in vivo and T-cell proliferation in vitro. These results provide initial evidence of safety and potency of Tat toxoid vaccination in HIV-1-infected individuals.

Effects of the TAT peptide orientation and relative location on the protein transduction efficiency.

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Guo, Qingguo; Zhao, Guojie; Hao, Fengjin; Guan, Yifu

2012-05-01

To understand the protein transduction domain (PTD)-mediated protein transduction behavior and to explore its potential in delivering biopharmaceutic drugs, we prepared four TAT-EGFP conjugates: TAT(+)-EGFP, TAT(-)-EGFP, EGFP-TAT(+) and EGFP-TAT(-), where TAT(+) and TAT(-) represent the original and the reversed TAT sequence, respectively. These four TAT-EGFP conjugates were incubated with HeLa and PC12 cells for in vitro study as well as injected intraperitoneally to mice for in vivo study. Flow cytometric results showed that four TAT-EGFP conjugates were able to traverse HeLa and PC12 cells with almost equal transduction efficiency. The in vivo study showed that the TAT-EGFP conjugates could be delivered into different organs of mice with different transduction capabilities. Bioinformatic analyses and CD spectroscopic data revealed that the TAT peptide has no defined secondary structure, and conjugating the TAT peptide to the EGFP cargo protein would not alter the native structure and the function of the EGFP protein. These results conclude that the sequence orientation, the spatial structure, and the relative location of the TAT peptide have much less effect on the TAT-mediated protein transduction. Thus, the TAT-fused conjugates could be constructed in more convenient and flexible formats for a wide range of biopharmaceutical applications. © 2011 John Wiley & Sons A/S.

Creatine protects against mitochondrial dysfunction associated with HIV-1 Tat-induced neuronal injury

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Stevens, Patrick R.; Gawryluk, Jeremy W.; Hui, Liang; Chen, Xuesong; Geiger, Jonathan D.

2015-01-01

HIV-1 infected individuals are living longer but experiencing a prevalence rate of over 50% for HIV-1 associated neurocognitive disorders (HAND) for which no effective treatment is available. Viral and cellular factors secreted by HIV-1 infected cells leads to neuronal injury and HIV-1 Tat continues to be implicated in the pathogenesis of HAND. Here we tested the hypothesis that creatine protected against HIV-1 Tat-induced neuronal injury by preventing mitochondrial bioenergetic crisis and/or redox catastrophe. Creatine blocked HIV-1 Tat1-72-induced increases in neuron cell death and synaptic area loss. Creatine protected against HIV-1 Tat-induced decreases in ATP. Creatine and creatine plus HIV-1 Tat increased cellular levels of creatine, and creatine plus HIV-1 Tat further decreased ratios of phosphocreatine to creatine observed with creatine or HIV-1 Tat treatments alone. Additionally, creatine protected against HIV-1 Tat-induced mitochondrial hypopolarization and HIV-1 Tat-induced mitochondrial permeability transition pore opening. Thus, creatine may be a useful adjunctive therapy against HAND. PMID:25613139

The Tat protein of human immunodeficiency virus-1 enhances hepatitis C virus replication through interferon gamma-inducible protein-10

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Qu Jing

2012-04-01

Full Text Available Abstract Background Co-infection with human immunodeficiency virus-1 (HIV-1 and hepatitis C virus (HCV is associated with faster progression of liver disease and an increase in HCV persistence. However, the mechanism by which HIV-1 accelerates the progression of HCV liver disease remains unknown. Results HIV-1/HCV co-infection is associated with increased expression of interferon gamma-induced protein-10 (IP-10 mRNA in peripheral blood mononuclear cells (PBMCs. HCV RNA levels were higher in PBMCs of patients with HIV-1/HCV co-infection than in patients with HCV mono-infection. HIV-1 Tat and IP-10 activated HCV replication in a time-dependent manner, and HIV-1 Tat induced IP-10 production. In addition, the effect of HIV-1 Tat on HCV replication was blocked by anti-IP-10 monoclonal antibody, demonstrating that the effect of HIV-1 Tat on HCV replication depends on IP-10. Taken together, these results suggest that HIV-1 Tat protein activates HCV replication by upregulating IP-10 production. Conclusions HIV-1/HCV co-infection is associated with increased expression of IP-10 mRNA and replication of HCV RNA. Furthermore, both HIV-1 Tat and IP-10 activate HCV replication. HIV-1 Tat activates HCV replication by upregulating IP-10 production. These results expand our understanding of HIV-1 in HCV replication and the mechanism involved in the regulation of HCV replication mediated by HIV-1 during co-infection.

In vivo monitoring of intranuclear p27{sup kip1} protein expression in breast cancer cells during trastuzumab (Herceptin) therapy

Energy Technology Data Exchange (ETDEWEB)

Cornelissen, Bart [Division of Nuclear Medicine, University Health Network, Toronto, ON, Canada M5S 3E2 (Canada); Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, M5S 3M2 (Canada); MRC/CRUK Gray Institute for Radiation Oncology and Biology, Oxford University, OX3 7LJ Oxford (United Kingdom)], E-mail: bart.cornelissen@rob.ox.ac.uk; Kersemans, Veerle; McLarty, Kristin [Division of Nuclear Medicine, University Health Network, Toronto, ON, M5S 3E2 (Canada); Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, M5S 3M2 (Canada); Tran, Lara [Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, M5S 3M2 (Canada); Vallis, Katherine A. [MRC/CRUK Gray Institute for Radiation Oncology and Biology, Oxford University, OX3 7LJ Oxford (United Kingdom); Reilly, Raymond M. [Division of Nuclear Medicine, University Health Network, Toronto, ON, M5S 3E2 (Canada); Department of Medical Imaging, University of Toronto, Toronto, ON, M5S 3E2 (Canada); Department of Pharmaceutical Sciences, University of Toronto, Toronto, ON, M5S 3M2 (Canada)

2009-10-15

Introduction: Trastuzumab, a humanized antibody directed against the Her2 receptor, induces the expression of p27{sup kip1}, an intranuclear cyclin-dependent kinase inhibitor in some breast cancer cells. The aim of this study was to develop a radioimmunoconjugate (RIC) to monitor trastuzumab-induced p27{sup kip1} protein up-regulation in vivo. Materials and Methods: Anti-p27{sup kip1} IgG was purified, and conjugated to diethylenetriaminopentaacetate, to allow radiolabeling with {sup 111}In for in vivo detection. Then tat peptide (GRKKRRQRRRPPQGYG), containing a nuclear localization sequence (underlined), was conjugated to the Fc-domain of IgG, using NaIO{sub 4} oxidation of carbohydrates and the resulting Schiff base stabilized with NaCNBH{sub 3}. The conjugate was radiolabeled with {sup 111}In, yielding [{sup 111}In]-anti-p27{sup kip1}-tat. {sup 111}In labeling efficiency, purity and p27{sup kip1} binding were measured. Trastuzumab-induced p27{sup kip1} up-regulation was assessed in a panel of breast cancer cell lines by Western blot analysis. Uptake and retention of [{sup 111}In]-anti-p27{sup kip1}-tat were measured in MDA-MB-361 and SKBr3 cells after exposure to trastuzumab. Uptake of [{sup 111}In]-anti-p27{sup kip1}-tat was determined at 72 h postintravenous injection in MDA-MB-361 xenografts in athymic mice treated with trastuzumab or saline. Results: [{sup 111}In]-anti-p27{sup kip1}-tat was synthesized to 97% purity. The RIC was able to bind to p27{sup kip1} protein and internalized in the cells and was transported to the nuclei of MDA-MB-361 cells. The level of p27{sup kip1} protein in MDA-MB-361 cells was increased after exposure to clinically relevant doses of trastuzumab for 3 days. Trastuzumab-mediated induction of p27{sup kip1} was not associated with increased cellular uptake or nuclear localization of [{sup 111}In]-anti-p27{sup kip1}-tat (6.53{+-}0.61% vs. 6.98{+-}1.36% internalized into trastuzumab-treated vs. control cells, respectively). However

Enhanced Cellular Uptake of Albumin-Based Lyophilisomes when Functionalized with Cell-Penetrating Peptide TAT in HeLa Cells

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van Bracht, Etienne; Versteegden, Luuk R. M.; Stolle, Sarah; Verdurmen, Wouter P. R.; Woestenenk, Rob; Raave, Rene; Hafmans, Theo; Oosterwijk, Egbert; Brock, Roland; van Kuppevelt, Toin H.; Daamen, Willeke F.

2014-01-01

Lyophilisomes are a novel class of biodegradable proteinaceous nano/micrometer capsules with potential use as drug delivery carrier. Cell-penetrating peptides (CPPs) including the TAT peptide have been successfully implemented for intracellular delivery of a broad variety of cargos including various

Intracellular trafficking of superparamagnetic iron oxide nanoparticles conjugated with TAT peptide: 3-dimensional electron tomography analysis

International Nuclear Information System (INIS)

Nair, Baiju G.; Fukuda, Takahiro; Mizuki, Toru; Hanajiri, Tatsuro; Maekawa, Toru

2012-01-01

Highlights: ► We study the intracellular localisation of TAT-SPIONs using 3-D electron tomography. ► 3-D images of TAT-SPIONs in a cell are clearly shown. ► Release of TAT-SPIONs from endocytic vesicles into the cytoplasm is clearly shown. -- Abstract: Internalisation of nanoparticles conjugated with cell penetrating peptides is a promising approach to various drug delivery applications. Cell penetrating peptides such as transactivating transcriptional activator (TAT) peptides derived from HIV-1 proteins are effective intracellular delivery vectors for a wide range of nanoparticles and pharmaceutical agents thanks to their amicable ability to enter cells and minimum cytotoxicity. Although different mechanisms of intracellular uptake and localisation have been proposed for TAT conjugated nanoparticles, it is necessary to visualise the particles on a 3-D plane in order to investigate the actual intracellular uptake and localisation. Here, we study the intracellular localisation and trafficking of TAT peptide conjugated superparamagnetic ion oxide nanoparticles (TAT-SPIONs) using 3-D electron tomography. 3-D tomograms clearly show the location of TAT-SPIONs in a cell and their slow release from the endocytic vesicles into the cytoplasm. The present methodology may well be utilised for further investigations of the behaviours of nanoparticles in cells and eventually for the development of nano drug delivery systems.

Intracellular trafficking of superparamagnetic iron oxide nanoparticles conjugated with TAT peptide: 3-dimensional electron tomography analysis

Energy Technology Data Exchange (ETDEWEB)

Nair, Baiju G.; Fukuda, Takahiro; Mizuki, Toru; Hanajiri, Tatsuro [Bio-Nano Electronics Research Centre, Toyo University, Saitama 350-8585 (Japan); Maekawa, Toru, E-mail: maekawa@toyo.jp [Bio-Nano Electronics Research Centre, Toyo University, Saitama 350-8585 (Japan)

2012-05-18

Highlights: Black-Right-Pointing-Pointer We study the intracellular localisation of TAT-SPIONs using 3-D electron tomography. Black-Right-Pointing-Pointer 3-D images of TAT-SPIONs in a cell are clearly shown. Black-Right-Pointing-Pointer Release of TAT-SPIONs from endocytic vesicles into the cytoplasm is clearly shown. -- Abstract: Internalisation of nanoparticles conjugated with cell penetrating peptides is a promising approach to various drug delivery applications. Cell penetrating peptides such as transactivating transcriptional activator (TAT) peptides derived from HIV-1 proteins are effective intracellular delivery vectors for a wide range of nanoparticles and pharmaceutical agents thanks to their amicable ability to enter cells and minimum cytotoxicity. Although different mechanisms of intracellular uptake and localisation have been proposed for TAT conjugated nanoparticles, it is necessary to visualise the particles on a 3-D plane in order to investigate the actual intracellular uptake and localisation. Here, we study the intracellular localisation and trafficking of TAT peptide conjugated superparamagnetic ion oxide nanoparticles (TAT-SPIONs) using 3-D electron tomography. 3-D tomograms clearly show the location of TAT-SPIONs in a cell and their slow release from the endocytic vesicles into the cytoplasm. The present methodology may well be utilised for further investigations of the behaviours of nanoparticles in cells and eventually for the development of nano drug delivery systems.

Crosstalk between HDAC6 and Nox2-based NADPH oxidase mediates HIV-1 Tat-induced pro-inflammatory responses in astrocytes

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Gi Soo Youn

2017-08-01

Full Text Available Histone deacetylase 6 (HDAC6 likely is important in inflammatory diseases. However, how HDAC6 exerts its effect on inflammatory processes remains unclear. HIV-1 transactivator of transcription (Tat activates NADPH oxidase resulting in generation of reactive oxygen species (ROS, leading to extensive neuro-inflammation in the central nervous system. We investigated the correlation of HDAC6 and NADPH oxidase in HIV-1 Tat-stimulated astrocytes. HDAC6 knockdown attenuated HIV-1 Tat-induced ROS generation and NADPH oxidase activation. HDAC6 knockdown suppressed HIV-1 Tat-induced expression of NADPH oxidase subunits, such as Nox2, p47phox, and p22phox. Specific inhibition of HDAC6 using tubastatin A suppressed HIV-1 Tat-induced ROS generation and activation of NADPH oxidase. N-acetyl cysteine, diphenyl iodonium, and apocynin suppressed HIV-1 Tat-induced expression of HDAC6 and the pro-inflammatory chemokines CCL2, CXCL8, and CXCL10. Nox2 knockdown attenuated HIV-1 Tat-induced HDAC6 expression and subsequent expression of chemokines. The collective results point to the potential crosstalk between HDAC6 and NADPH oxidase, which could be a combined therapeutic target for relief of HIV-1 Tat-mediated neuro-inflammation. Keywords: HIV-1 Tat, HDAC6, NADPH oxidase, ROS, Inflammation, Astrocytes

A Tat-grafted anti-nucleic acid antibody acquires nuclear-localization property and a preference for TAR RNA

International Nuclear Information System (INIS)

Jeong, Jong-Geun; Kim, Dong-Sik; Kim, Yong-Sung; Kwon, Myung-Hee

2011-01-01

Highlights: → We generate ' H3 Tat-3D8' by grafting Tat 48-60 peptide to VH CDR of 3D8 scFv antibody. → H3 Tat-3D8 antibody retains nucleic acid binding and hydrolyzing activities. → H3 Tat-3D8 acquires a preference for TAR RNA structure. → Properties of Tat 48-60 is transferred to an antibody via Tat-grafting into a CDR. -- Abstract: The 3D8 single chain variable fragment (3D8 scFv) is an anti-nucleic acid antibody that can hydrolyze nucleic acids and enter the cytosol of cells without reaching the nucleus. The Tat peptide, derived from the basic region of the HIV-1 Tat protein, translocates to cell nuclei and has TAR RNA binding activity. In this study, we generated a Tat-grafted antibody ( H3 Tat-3D8) by replacing complementarity-determining region 3 (CDR3) within the VH domain of the 3D8 scFv with a Tat 48-60 peptide (GRKKRRQRRRPPQ). H3 Tat-3D8 retained the DNA-binding and DNA-hydrolyzing activity of the scFv, and translocated to the nuclei of HeLa cells and preferentially recognized TAR RNA. Thus, the properties associated with the Tat peptide were transferred to the antibody via Tat-grafting without loss of the intrinsic DNA-binding and hydrolyzing activities of the 3D8 scFv antibody.

Preliminary study on the inhibition of nuclear internalization of Tat peptides by conjugation with a receptor-specific peptide and fluorescent dyes

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Shen, Duanwen; Liang, Kexiang; Ye, Yunpeng; Tetteh, Elizabeth; Achilefu, Samuel

2006-02-01

Numerous studies have shown that basic Tat peptide (48-57) internalized non-specifically in cells and localized in the nucleus. However, localization of imaging agents in cellular nucleus is not desirable because of the potential mutagenesis. When conjugated to the peptides that undergo receptor-mediated endocytosis, Tat peptide could target specific cells or pathologic tissue. We tested this hypothesis by incorporating a somatostatin receptor-avid peptide (octreotate, Oct) and two different fluorescent dyes, Cypate 2 (Cy2) and fluorescein 5'-carboxlic acid (5-FAM), into the Tat-peptide sequence. In addition to the Cy2 or 5-FAM-labeled Oct conjugated to Tat peptide (Tat) to produce Tat-Oct-Cypate2 or Tat-Oct-5-FAM, we also labeled the Tat the Tat peptide with these dyes (Tat-Cy2 and Tat-5-FAM) to serve as positive control. A somatostatin receptor-positive pancreatic tumor cell line, AR42J, was used to assess cell internalization. The results show that Tat-5-FAM and Tat-Cypate2 localized in both nucleus and cytoplasm of the cells. In contrast to Tat-Oct-Cypate2, which localized in both the cytoplasm and nucleus, Tat-Oct-5-FAM internalized in the cytoplasm but not in the nucleus of AR42J cells. The internalizations were inhibited by adding non-labeled corresponding peptides, suggesting that the endocytoses of each group of labeled and the corresponding unlabeled compounds occurred through a common pathway. Thus, fluorescent probes and endocytosis complex between octreotate and somatostatin receptors in cytoplasm could control nuclear internalization of Tat peptides.

Fractalkine/CX3CL1 protects striatal neurons from synergistic morphine and HIV-1 Tat-induced dendritic losses and death

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Suzuki Masami

2011-11-01

Full Text Available Abstract Background Fractalkine/CX3CL1 and its cognate receptor CX3CR1 are abundantly expressed in the CNS. Fractalkine is an unusual C-X3-C motif chemokine that is important in neuron-microglial communication, a co-receptor for HIV infection, and can be neuroprotective. To assess the effects of fractalkine on opiate-HIV interactive neurotoxicity, wild-type murine striatal neurons were co-cultured with mixed glia from the striata of wild-type or Cx3cr1 knockout mice ± HIV-1 Tat and/or morphine. Time-lapse digital images were continuously recorded at 20 min intervals for up to 72 h using computer-aided microscopy to track the same cells repeatedly. Results Co-exposure to Tat and morphine caused synergistic increases in neuron death, dendritic pruning, and microglial motility as previously reported. Exogenous fractalkine prevented synergistic Tat and morphine-induced dendritic losses and neuron death even though the inflammatory mediator TNF-α remained significantly elevated. Antibody blockade of CX3CR1 mimicked the toxic effects of morphine plus Tat, but did not add to their toxicity; while fractalkine failed to protect wild-type neurons co-cultured with Cx3cr1-/--null glia against morphine and Tat toxicity. Exogenous fractalkine also normalized microglial motility, which is elevated by Tat and morphine co-exposure, presumably limiting microglial surveillance that may lead to toxic effects on neurons. Fractalkine immunofluorescence was expressed in neurons and to a lesser extent by other cell types, whereas CX3CR1 immunoreactivity or GFP fluorescence in cells cultured from the striatum of Cx3cr1-/- (Cx3cr1GFP/GFP mice were associated with microglia. Immunoblotting shows that fractalkine levels were unchanged following Tat and/or morphine exposure and there was no increase in released fractalkine as determined by ELISA. By contrast, CX3CR1 protein levels were markedly downregulated. Conclusions The results suggest that deficits in fractalkine

A Tat-conjugated Peptide Nucleic Acid Tat-PNA-DR Inhibits Hepatitis B Virus Replication In Vitro and In Vivo by Targeting LTR Direct Repeats of HBV RNA

Science.gov (United States)

Zeng, Zhengyang; Han, Shisong; Hong, Wei; Lang, Yange; Li, Fangfang; Liu, Yongxiang; Li, Zeyong; Wu, Yingliang; Li, Wenxin; Zhang, Xianzheng; Cao, Zhijian

2016-01-01

Hepatitis B virus (HBV) infection is a major cause of chronic active hepatitis, cirrhosis, and primary hepatocellular carcinoma, all of which are severe threats to human health. However, current clinical therapies for HBV are limited by potential side effects, toxicity, and drug-resistance. In this study, a cell-penetrating peptide-conjugated peptide nucleic acid (PNA), Tat-PNA-DR, was designed to target the direct repeat (DR) sequences of HBV. Tat-PNA-DR effectively inhibited HBV replication in HepG2.2.15 cells. Its anti-HBV effect relied on the binding of Tat-PNA-DR to the DR, whereby it suppressed the translation of hepatitis B e antigen (HBeAg), HBsAg, HBV core, hepatitis B virus x protein, and HBV reverse transcriptase (RT) and the reverse transcription of the HBV genome. Furthermore, Tat-PNA-DR administered by intravenous injection efficiently cleared HBeAg and HBsAg in an acute hepatitis B mouse model. Importantly, it induced an 80% decline in HBV DNA in mouse serum, which was similar to the effect of the widely used clinical drug Lamivudine (3TC). Additionally, a long-term hydrodynamics HBV mouse model also demonstrated Tat-PNA-DR's antiviral effect. Interestingly, Tat-PNA-DR displayed low cytotoxicity, low mouse acute toxicity, low immunogenicity, and high serum stability. These data indicate that Tat-PNA-DR is a unique PNA and a promising drug candidate against HBV. PMID:26978579

A Tat-conjugated Peptide Nucleic Acid Tat-PNA-DR Inhibits Hepatitis B Virus Replication In Vitro and In Vivo by Targeting LTR Direct Repeats of HBV RNA

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Zhengyang Zeng

2016-01-01

Full Text Available Hepatitis B virus (HBV infection is a major cause of chronic active hepatitis, cirrhosis, and primary hepatocellular carcinoma, all of which are severe threats to human health. However, current clinical therapies for HBV are limited by potential side effects, toxicity, and drug-resistance. In this study, a cell-penetrating peptide-conjugated peptide nucleic acid (PNA, Tat-PNA-DR, was designed to target the direct repeat (DR sequences of HBV. Tat-PNA-DR effectively inhibited HBV replication in HepG2.2.15 cells. Its anti-HBV effect relied on the binding of Tat-PNA-DR to the DR, whereby it suppressed the translation of hepatitis B e antigen (HBeAg, HBsAg, HBV core, hepatitis B virus x protein, and HBV reverse transcriptase (RT and the reverse transcription of the HBV genome. Furthermore, Tat-PNA-DR administered by intravenous injection efficiently cleared HBeAg and HBsAg in an acute hepatitis B mouse model. Importantly, it induced an 80% decline in HBV DNA in mouse serum, which was similar to the effect of the widely used clinical drug Lamivudine (3TC. Additionally, a long-term hydrodynamics HBV mouse model also demonstrated Tat-PNA-DR's antiviral effect. Interestingly, Tat-PNA-DR displayed low cytotoxicity, low mouse acute toxicity, low immunogenicity, and high serum stability. These data indicate that Tat-PNA-DR is a unique PNA and a promising drug candidate against HBV.

Morphine Tolerance and Physical Dependence Are Altered in Conditional HIV-1 Tat Transgenic Mice.

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Fitting, Sylvia; Stevens, David L; Khan, Fayez A; Scoggins, Krista L; Enga, Rachel M; Beardsley, Patrick M; Knapp, Pamela E; Dewey, William L; Hauser, Kurt F

2016-01-01

Despite considerable evidence that chronic opiate use selectively affects the pathophysiologic consequences of human immunodeficiency virus type 1 (HIV-1) infection in the nervous system, few studies have examined whether neuro-acquired immune deficiency syndrome (neuroAIDS) might intrinsically alter the pharmacologic responses to chronic opiate exposure. This is an important matter because HIV-1 and opiate abuse are interrelated epidemics, and HIV-1 patients are often prescribed opiates as a treatment of HIV-1-related neuropathic pain. Tolerance and physical dependence are inevitable consequences of frequent and repeated administration of morphine. In the present study, mice expressing HIV-1 Tat in a doxycycline (DOX)-inducible manner [Tat(+)], their Tat(-) controls, and control C57BL/6 mice were chronically exposed to placebo or 75-mg morphine pellets to explore the effects of Tat induction on morphine tolerance and dependence. Antinociceptive tolerance and locomotor activity tolerance were assessed using tail-flick and locomotor activity assays, respectively, and physical dependence was measured with the platform-jumping assay and recording of other withdrawal signs. We found that Tat(+) mice treated with DOX [Tat(+)/DOX] developed an increased tolerance in the tail-flick assay compared with control Tat(-)/DOX and/or C57/DOX mice. Equivalent tolerance was developed in all mice when assessed by locomotor activity. Further, Tat(+)/DOX mice expressed reduced levels of physical dependence to chronic morphine exposure after a 1-mg/kg naloxone challenge compared with control Tat(-)/DOX and/or C57/DOX mice. Assuming the results seen in Tat transgenic mice can be generalized to neuroAIDS, our findings suggest that HIV-1-infected individuals may display heightened analgesic tolerance to similar doses of opiates compared with uninfected individuals and show fewer symptoms of physical dependence. Copyright © 2015 by The American Society for Pharmacology and Experimental

HIV-1 Tat reduces nephrin in human podocytes: a potential mechanism for enhanced glomerular permeability in HIV-associated nephropathy.

Science.gov (United States)

Doublier, Sophie; Zennaro, Cristina; Spatola, Tiziana; Lupia, Enrico; Bottelli, Antonella; Deregibus, Maria Chiara; Carraro, Michele; Conaldi, Pier Giulio; Camussi, Giovanni

2007-02-19

To determine whether HIV-1 Tat may directly alter glomerular permeability in HIV-associated nephropathy (HIVAN). Heavy proteinuria is a hallmark of HIVAN. The slit diaphragm is the ultimate glomerular filtration barrier critical for maintaining the efficiency of the ultrafiltration unit of the kidney. In this study, we evaluated the direct effect of Tat protein on the permeability of isolated glomeruli and on the expression of nephrin, the main slit diaphragm component, by human cultured podocytes. Permeability was studied by measuring the permeability to albumin in isolated rat glomeruli. We also evaluated the expression of nephrin in human cultured podocytes by using immunofluorescence and Western blot. We found that Tat increased albumin permeability in isolated glomeruli, and rapidly induced the redistribution and loss of nephrin in cultured podocytes. Pretreatment of glomeruli and podocytes with blocking antibodies showed that Tat reduced nephrin expression by engaging vascular endothelial growth factor receptors types 2 and 3 and the integrin alphavbeta3. Pre-incubation of podocytes with two platelet-activating factor (PAF) receptor antagonists prevented the loss and redistribution of nephrin induced by Tat, suggesting that PAF is an intracellular mediator of Tat action. Tat induced a rapid PAF synthesis by podocytes. When podocytes transfected to overexpress PAF-acetylhydrolase, the main catabolic enzyme of PAF, were stimulated with Tat, the redistribution and loss of nephrin was abrogated. The present results define a mechanism by which Tat may reduce nephrin expression in podocytes, thus increasing glomerular permeability. This provides new insights in the understanding of HIVAN pathogenesis.

Alternative Mechanisms for the Interaction of the Cell-Penetrating Peptides Penetratin and the TAT Peptide with Lipid Bilayers

NARCIS (Netherlands)

Yesylevskyy, Semen; Marrink, Siewert-Jan; Mark, Alan E.

2009-01-01

Cell-penetrating peptides (CPPs) have recently attracted much interest due to their apparent ability to penetrate cell membranes in an energy-independent manner. Here molecular-dynamics simulation techniques were used to study the interaction of two CPPs: penetratin and the TAT peptide with

TAT-Mediated Delivery of Tousled Protein to Salivary Glands Protects Against Radiation-Induced Hypofunction

Energy Technology Data Exchange (ETDEWEB)

Sunavala-Dossabhoy, Gulshan, E-mail: gsunav@lsuhsc.edu [Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA (United States); Palaniyandi, Senthilnathan; Richardson, Charles; De Benedetti, Arrigo [Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA (United States); Schrott, Lisa [Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA (United States); Caldito, Gloria [Department of Bioinformatics and Computational Biology, Louisiana State University Health Sciences Center, Shreveport, LA (United States)

2012-09-01

Purpose: Patients treated with radiotherapy for head-and-neck cancer invariably suffer its deleterious side effect, xerostomia. Salivary hypofunction ensuing from the irreversible destruction of glands is the most common and debilitating oral complication affecting patients undergoing regional radiotherapy. Given that the current management of xerostomia is palliative and ineffective, efforts are now directed toward preventive measures to preserve gland function. The human homolog of Tousled protein, TLK1B, facilitates chromatin remodeling at DNA repair sites and improves cell survival against ionizing radiation (IR). Therefore, we wanted to determine whether a direct transfer of TLK1B protein to rat salivary glands could protect against IR-induced salivary hypofunction. Methods: The cell-permeable TAT-TLK1B fusion protein was generated. Rat acinar cell line and rat salivary glands were pretreated with TAT peptide or TAT-TLK1B before IR. The acinar cell survival in vitro and salivary function in vivo were assessed after radiation. Results: We demonstrated that rat acinar cells transduced with TAT-TLK1B were more resistant to radiation (D{sub 0} = 4.13 {+-} 1.0 Gy; {alpha}/{beta} = 0 Gy) compared with cells transduced with the TAT peptide (D{sub 0} = 4.91 {+-} 1.0 Gy; {alpha}/{beta} = 20.2 Gy). Correspondingly, retroductal instillation of TAT-TLK1B in rat submandibular glands better preserved salivary flow after IR (89%) compared with animals pretreated with Opti-MEM or TAT peptide (31% and 39%, respectively; p < 0.01). Conclusions: The results demonstrate that a direct transfer of TLK1B protein to the salivary glands effectively attenuates radiation-mediated gland dysfunction. Prophylactic TLK1B-protein therapy could benefit patients undergoing radiotherapy for head-and-neck cancer.

Evaluation of the internalization kinetics of the radiopharmaceutical 99mTc-N2S2-Tat(49-57)Lys3-Bn with diagnostic purposes, using comet assay

International Nuclear Information System (INIS)

Luna G, M. A.

2011-01-01

Gastrin-rea leasing peptide receptors (GRP-r) are over expressed in breast and prostate cancer cells. Bombesin (Bn) binds specifically and strongly to GRP-r and this is the base for to label the Bn with radionuclides by gamma rays. Tat (49-57) is a peptide that across the cell membrane easily so that, when it is conjugated to different proteins, it can works as a Trojan horse, facilitating the drug internalization to the cells. The radiopharmaceutical 99m Tc-N 2 S 2 -Tat(49-57)-Lys 3 -Bn was prepared for diagnosis and therapy at early stage of breast cancer. The objective of this study was to determine the role of Tat in the internalization kinetics of radiopharmaceuticals measured by DNA damage induced by means of comet assay. Human lymphocytes were treated with the following protocols: a) Tat-Bn, b) 99m Tc-Bn, or c) 99m Tc-N 2 S 2 -Tat(49-57)-Lys 3 -Bn, also an untreated group was conformed. The internalization was evaluated at 0, 5, 10, 15, 30 and 60 min after exposure with three repetitions each one, and for radiopharmaceuticals with 2.9, 6.6, 9.0 and 14.8 MBq activities. DNA damage was scored in 100 cells per time and treatment, as tail length and tail moment. A Kruskal-Wallis variance analysis with p≤ 0.05 was applied for comparison between treatments. The results showed that the damage caused by 99m Tc-N 2 S 2 -Tat(49-57)-Lys 3 -Bn is significantly higher than that caused by 99m Tc-Bn and Tat-Bn, showing that Tat favors the internalization of the radiopharmaceutical. (Author)

Targeted PEG-based bioconjugates enhance the cellular uptake and transport of a HIV-1 TAT nonapeptide.

Science.gov (United States)

Ramanathan, S; Qiu, B; Pooyan, S; Zhang, G; Stein, S; Leibowitz, M J; Sinko, P J

2001-12-13

We previously described the enhanced cell uptake and transport of R.I-K(biotin)-Tat9, a large ( approximately 1500 Da) peptidic inhibitor of HIV-1 Tat protein, via SMVT, the intestinal biotin transporter. The aim of the present study was to investigate the feasibility of targeting biotinylated PEG-based conjugates to SMVT in order to enhance cell uptake and transport of Tat9. The 29 kDa peptide-loaded bioconjugate (PEG:(R.I-Cys-K(biotin)-Tat9)8) used in these studies contained eight copies of R.I-K(biotin)-Tat9 appended to PEG by means of a cysteine linkage. The absorptive transport of biotin-PEG-3400 (0.6-100 microM) and the bioconjugate (0.1-30 microM) was studied using Caco-2 cell monolayers. Inhibition of biotin-PEG-3400 by positive controls (biotin, biocytin, and desthiobiotin) was also determined. Uptake of these two compounds was also determined in CHO cells transfected with human SMVT (CHO/hSMVT) and control cells (CHO/pSPORT) over the concentration ranges of 0.05-12.5 microM and 0.003-30 microM, respectively. Nonbiotinylated forms of these two compounds, PEG-3350 and PEG:(R.I-Cys-K-Tat9)8, were used in the control studies. Biotin-PEG-3400 transport was found to be concentration-dependent and saturable in Caco-2 cells (K(m)=6.61 microM) and CHO/hSMVT cells (K(m)=1.26 microM). Transport/uptake was significantly inhibited by positive control substrates of SMVT. PEG:(R.I-Cys-K(biotin)Tat9)8 also showed saturable transport kinetics in Caco-2 cells (K(m)=6.13 microM) and CHO/hSMVT cells (K(m)=8.19 microM). Maximal uptake in molar equivalents of R.I-Cys-K(biotin)Tat9 was 5.7 times greater using the conjugate versus the biotinylated peptide alone. Transport of the nonbiotinylated forms was significantly lower (PPEG-3400 and PEG:(R.I-Cys-K(biotin)Tat9)8 interact with human SMVT to enhance the cellular uptake and transport of these larger molecules and that targeted bioconjugates may have potential for enhancing the cellular uptake and transport of small peptide

In vitro assessment of TAT — Ciliary Neurotrophic Factor therapeutic potential for peripheral nerve regeneration

International Nuclear Information System (INIS)

Barbon, Silvia; Stocco, Elena; Negro, Alessandro; Dalzoppo, Daniele; Borgio, Luca; Rajendran, Senthilkumar; Grandi, Francesca; Porzionato, Andrea; Macchi, Veronica; De Caro, Raffaele

2016-01-01

In regenerative neurobiology, Ciliary Neurotrophic Factor (CNTF) is raising high interest as a multifunctional neurocytokine, playing a key role in the regeneration of injured peripheral nerves. Despite its promising trophic and regulatory activity, its clinical application is limited by the onset of severe side effects, due to the lack of efficient intracellular trafficking after administration. In this study, recombinant CNTF linked to the transactivator transduction domain (TAT) was investigated in vitro and found to be an optimized fusion protein which preserves neurotrophic activity, besides enhancing cellular uptake for therapeutic advantage. Moreover, a compelling protein delivery method was defined, in the future perspective of improving nerve regeneration strategies. Following determination of TAT-CNTF molecular weight and concentration, its specific effect on neural SH-SY5Y and PC12 cultures was assessed. Cell proliferation assay demonstrated that the fusion protein triggers PC12 cell growth within 6 h of stimulation. At the same time, the activation of signal transduction pathway and enhancement of cellular trafficking were found to be accomplished in both neural cell lines after specific treatment with TAT-CNTF. Finally, the recombinant growth factor was successfully loaded on oxidized polyvinyl alcohol (PVA) scaffolds, and more efficiently released when polymer oxidation rate increased. Taken together, our results highlight that the TAT domain addiction to the protein sequence preserves CNTF specific neurotrophic activity in vitro, besides improving cellular uptake. Moreover, oxidized PVA could represent an ideal biomaterial for the development of nerve conduits loaded with the fusion protein to be delivered to the site of nerve injury. - Highlights: • TAT-CNTF is an optimized fusion protein that preserves neurotrophic activity. • In neural cell lines, TAT-CNTF triggers the activation of signal transduction. • Fast cellular uptake of TAT-CNTF was

In vitro assessment of TAT — Ciliary Neurotrophic Factor therapeutic potential for peripheral nerve regeneration

Energy Technology Data Exchange (ETDEWEB)

Barbon, Silvia, E-mail: silvia.barbon@yahoo.it [Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Via Marzolo 5, 35131 Padua (Italy); Foundation for Biology and Regenerative Medicine, Tissue Engineering and Signaling (TES) ONLUS, Via De Sanctis 10, Caselle di Selvazzano Dentro, 35030 Padua (Italy); Stocco, Elena, E-mail: elena.stocco@gmail.com [Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Via Marzolo 5, 35131 Padua (Italy); Foundation for Biology and Regenerative Medicine, Tissue Engineering and Signaling (TES) ONLUS, Via De Sanctis 10, Caselle di Selvazzano Dentro, 35030 Padua (Italy); Negro, Alessandro, E-mail: alessandro.negro@unipd.it [Department of Biomedical Sciences, University of Padova, Via Colombo 3, 35121 Padua (Italy); Dalzoppo, Daniele, E-mail: daniele.dalzoppo@unipd.it [Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Via Marzolo 5, 35131 Padua (Italy); Borgio, Luca, E-mail: borgio.luca@gmail.com [Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Via Marzolo 5, 35131 Padua (Italy); Rajendran, Senthilkumar, E-mail: senthilstem@gmail.com [Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Via Marzolo 5, 35131 Padua (Italy); Grandi, Francesca, E-mail: francesca.grandi7825@gmail.com [Department of Women' s and Children' s Health, Pediatric Surgery, University of Padua, Via Giustiniani 3, 35121 Padua (Italy); Porzionato, Andrea, E-mail: andrea.porzionato@unipd.it [Section of Human Anatomy, Department of Molecular Medicine, University of Padua, Via Gabelli 65, 35121 Padua (Italy); Macchi, Veronica, E-mail: veronica.macchi@unipd.it [Section of Human Anatomy, Department of Molecular Medicine, University of Padua, Via Gabelli 65, 35121 Padua (Italy); De Caro, Raffaele, E-mail: raffaele.decaro@unipd.it [Section of Human Anatomy, Department of Molecular Medicine, University of Padua, Via Gabelli 65, 35121 Padua (Italy); and others

2016-10-15

In regenerative neurobiology, Ciliary Neurotrophic Factor (CNTF) is raising high interest as a multifunctional neurocytokine, playing a key role in the regeneration of injured peripheral nerves. Despite its promising trophic and regulatory activity, its clinical application is limited by the onset of severe side effects, due to the lack of efficient intracellular trafficking after administration. In this study, recombinant CNTF linked to the transactivator transduction domain (TAT) was investigated in vitro and found to be an optimized fusion protein which preserves neurotrophic activity, besides enhancing cellular uptake for therapeutic advantage. Moreover, a compelling protein delivery method was defined, in the future perspective of improving nerve regeneration strategies. Following determination of TAT-CNTF molecular weight and concentration, its specific effect on neural SH-SY5Y and PC12 cultures was assessed. Cell proliferation assay demonstrated that the fusion protein triggers PC12 cell growth within 6 h of stimulation. At the same time, the activation of signal transduction pathway and enhancement of cellular trafficking were found to be accomplished in both neural cell lines after specific treatment with TAT-CNTF. Finally, the recombinant growth factor was successfully loaded on oxidized polyvinyl alcohol (PVA) scaffolds, and more efficiently released when polymer oxidation rate increased. Taken together, our results highlight that the TAT domain addiction to the protein sequence preserves CNTF specific neurotrophic activity in vitro, besides improving cellular uptake. Moreover, oxidized PVA could represent an ideal biomaterial for the development of nerve conduits loaded with the fusion protein to be delivered to the site of nerve injury. - Highlights: • TAT-CNTF is an optimized fusion protein that preserves neurotrophic activity. • In neural cell lines, TAT-CNTF triggers the activation of signal transduction. • Fast cellular uptake of TAT-CNTF was

RNA glycosidase and other agents target Tat to inhibit HIV-1 transcription.

Science.gov (United States)

Harrich, David; Jin, Hongping

2018-03-20

The HIV-1 tat gene encodes a small 86-104 amino acid protein depending on the HIV-1 strain. Tat is essential for HIV-1 replication through interactions with numerous cellular transcription factors. The interaction between Tat and P-TEFb, which is a cellular protein complex composed of cyclin T1 and CDK9, delivers P-TEFb to the newly transcribed viral mRNAs where phosphorylation of RNA polymerase II by CDK9 leads to highly efficient mRNA transcription. It has long been recognized that Tat is a potential anti-HIV-1 target and possibly a viral Achilles' heel. However, specifically targeting Tat without affecting normal host cell functions has been challenging. Means to inactivate Tat have been reported that includes small compounds, transdominant negative Tat proteins, and by plant-derived antivirals. Investigations of these agents have reported encouraging outcomes that inform and may hopefully affect strategies for a functional HIV-1 cure. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Evaluation of the internalization kinetics of the radiopharmaceutical {sup 99m}Tc-N{sub 2}S{sub 2}-Tat(49-57)Lys{sup 3}-Bn with diagnostic purposes, using comet assay; Evaluacion de la cinetica de internalizacion del radiofarmaco {sup 99m}Tc-N{sub 2}S{sub 2}-TAT(49-57)Lys{sup 3}-BN con fines diagnosticos, empleando ensayo cometa

Energy Technology Data Exchange (ETDEWEB)

Luna G, M. A.

2011-07-01

Gastrin-rea leasing peptide receptors (GRP-r) are over expressed in breast and prostate cancer cells. Bombesin (Bn) binds specifically and strongly to GRP-r and this is the base for to label the Bn with radionuclides by gamma rays. Tat (49-57) is a peptide that across the cell membrane easily so that, when it is conjugated to different proteins, it can works as a Trojan horse, facilitating the drug internalization to the cells. The radiopharmaceutical {sup 99m}Tc-N{sub 2}S{sub 2}-Tat(49-57)-Lys{sup 3}-Bn was prepared for diagnosis and therapy at early stage of breast cancer. The objective of this study was to determine the role of Tat in the internalization kinetics of radiopharmaceuticals measured by DNA damage induced by means of comet assay. Human lymphocytes were treated with the following protocols: a) Tat-Bn, b) {sup 99m}Tc-Bn, or c) {sup 99m}Tc-N{sub 2}S{sub 2}-Tat(49-57)-Lys{sup 3}-Bn, also an untreated group was conformed. The internalization was evaluated at 0, 5, 10, 15, 30 and 60 min after exposure with three repetitions each one, and for radiopharmaceuticals with 2.9, 6.6, 9.0 and 14.8 MBq activities. DNA damage was scored in 100 cells per time and treatment, as tail length and tail moment. A Kruskal-Wallis variance analysis with p{<=} 0.05 was applied for comparison between treatments. The results showed that the damage caused by {sup 99m}Tc-N{sub 2}S{sub 2}-Tat(49-57)-Lys{sup 3}-Bn is significantly higher than that caused by {sup 99m}Tc-Bn and Tat-Bn, showing that Tat favors the internalization of the radiopharmaceutical. (Author)

A real-time view of the TAR:Tat:P-TEFb complex at HIV-1 transcription sites

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Knezevich Anna

2007-05-01

Full Text Available Abstract HIV-1 transcription is tightly regulated: silent in long-term latency and highly active in acutely-infected cells. Transcription is activated by the viral protein Tat, which recruits the elongation factor P-TEFb by binding the TAR sequence present in nascent HIV-1 RNAs. In this study, we analyzed the dynamic of the TAR:Tat:P-TEFb complex in living cells, by performing FRAP experiments at HIV-1 transcription sites. Our results indicate that a large fraction of Tat present at these sites is recruited by Cyclin T1. We found that in the presence of Tat, Cdk9 remained bound to nascent HIV-1 RNAs for 71s. In contrast, when transcription was activated by PMA/ionomycin, in the absence of Tat, Cdk9 turned-over rapidly and resided on the HIV-1 promoter for only 11s. Thus, the mechanism of trans-activation determines the residency time of P-TEFb at the HIV-1 gene, possibly explaining why Tat is such a potent transcriptional activator. In addition, we observed that Tat occupied HIV-1 transcription sites for 55s, suggesting that the TAR:Tat:P-TEFb complex dissociates from the polymerase following transcription initiation, and undergoes subsequent cycles of association/dissociation.

Labeling Efficacy of Superparamagnetic Iron Oxide Nanoparticles to Human Neural Stem Cells: Comparison of Ferumoxides, Monocrystalline Iron Oxide, Cross-linked Iron Oxide (CLIO)-NH2 and tat-CLIO

International Nuclear Information System (INIS)

Song, Mi Yeoun; Moon, Woo Kyung; Kim, Yun Hee; Song, In Chan; Yoon, Byung Woo; Lim, Dong Yeol

2007-01-01

We wanted to compare the human neural stem cell (hNSC) labeling efficacy of different superparamagnetic iron oxide nanoparticles (SPIONs), namely, ferumoxides, monocrystalline iron oxide (MION), cross-linked iron oxide (CLIO)-NH 2 and tat-CLIO. The hNSCs (5x10 5 HB1F3 cells/ml) were incubated for 24 hr in cell culture media that contained 25 μg/ml of ferumoxides, MION or CLIO-NH 2 , and with or without poly-L-lysine (PLL) and tat-CLIO. The cellular iron uptake was analyzed qualitatively with using a light microscope and this was quantified via atomic absorption spectrophotometry. The visibility of the labeled cells was assessed with MR imaging. The incorporation of SPIONs into the hNSCs did not affect the cellular proliferations and viabilities. The hNSCs labeled with tat-CLIO showed the longest retention, up to 72 hr, and they contained 2.15± 0.3 pg iron/cell, which are 59 fold, 430 fold and six fold more incorporated iron than that of the hNSCs labeled with ferumoxides, MION or CLIO-NH 2 , respectively. However, when PLL was added, the incorporation of ferumoxides, MION or CLIO-NH 2 into the hNSCs was comparable to that of tat-CLIO. For MR imaging, hNSCs can be efficiently labeled with tat-CLIO alone or with a combination of ferumoxides, MION, CLIO-NH 2 and the transfection agent PLL

Labeling Efficacy of Superparamagnetic Iron Oxide Nanoparticles to Human Neural Stem Cells: Comparison of Ferumoxides, Monocrystalline Iron Oxide, Cross-linked Iron Oxide (CLIO)-NH2 and tat-CLIO

Science.gov (United States)

Song, Miyeoun; Kim, Yunhee; Lim, Dongyeol; Song, In-Chan; Yoon, Byung-Woo

2007-01-01

Objective We wanted to compare the human neural stem cell (hNSC) labeling efficacy of different superparamagnetic iron oxide nanoparticles (SPIONs), namely, ferumoxides, monocrystalline iron oxide (MION), cross-linked iron oxide (CLIO)-NH2 and tat-CLIO. Materials and Methods The hNSCs (5 × 105 HB1F3 cells/ml) were incubated for 24 hr in cell culture media that contained 25 µg/ml of ferumoxides, MION or CLIO-NH2, and with or without poly-L-lysine (PLL) and tat-CLIO. The cellular iron uptake was analyzed qualitatively with using a light microscope and this was quantified via atomic absorption spectrophotometry. The visibility of the labeled cells was assessed with MR imaging. Results The incorporation of SPIONs into the hNSCs did not affect the cellular proliferations and viabilities. The hNSCs labeled with tat-CLIO showed the longest retention, up to 72 hr, and they contained 2.15 ± 0.3 pg iron/cell, which are 59 fold, 430 fold and six fold more incorporated iron than that of the hNSCs labeled with ferumoxides, MION or CLIO-NH2, respectively. However, when PLL was added, the incorporation of ferumoxides, MION or CLIO-NH2 into the hNSCs was comparable to that of tat-CLIO. Conclusion For MR imaging, hNSCs can be efficiently labeled with tat-CLIO alone or with a combination of ferumoxides, MION, CLIO-NH2 and the transfection agent PLL. PMID:17923778

Assessment of the chemosensitizing activity of TAT-RasGAP317-326 in childhood cancers.

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Nadja Chevalier

Full Text Available Although current anti-cancer protocols are reasonably effective, treatment-associated long-term side effects, induced by lack of specificity of the anti-cancer procedures, remain a challenging problem in pediatric oncology. TAT-RasGAP317-326 is a RasGAP-derived cell-permeable peptide that acts as a sensitizer to various anti-cancer treatments in adult tumor cells. In the present study, we assessed the effect of TAT-RasGAP317-326 in several childhood cancer cell lines. The RasGAP-derived peptide-induced cell death was analyzed in several neuroblastoma, Ewing sarcoma and leukemia cell lines (as well as in normal lymphocytes. Cell death was evaluated using flow cytometry methods in the absence or in the presence of the peptide in combination with various genotoxins used in the clinics (4-hydroperoxycyclophosphamide, etoposide, vincristine and doxorubicin. All tested pediatric tumors, in response to at least one genotoxin, were sensitized by TAT-RasGAP317-326. The RasGAP-derived peptide did not increase cell death of normal lymphocytes, alone or in combination with the majority of the tested chemotherapies. Consequently, TAT-RasGAP317-326 may benefit children with tumors by increasing the efficacy of anti-cancer therapies notably by allowing reductions in anti-cancer drug dosage and the associated drug-induced side effects.

TAT improves in vitro transportation of fortilin through midgut and into hemocytes of white shrimp Litopenaeus vannamei

Science.gov (United States)

Zhou, Yi; Zhang, Wenbing; Mai, Kangsen; Xu, Wei; Zhang, Yanjiao; Ai, Qinghui; Wang, Xiaojie

2012-06-01

Fortilin is a multifunctional protein implicated in many important cellular processes. Since injection of Pm-fortilin reduces shrimp mortality caused by white spot syndrome virus (WSSV), there is potential application of fortilin in shrimp culture. In the present study, in order to improve trans-membrane transportation efficiency, the protein transduction domain of the transactivator of transcription (TAT) peptide was fused to fortilin. The Pichia pastoris yeast expression system, which is widely accepted in animal feeds, was used for production of recombinant fusion protein. Green fluorescence protein (GFP) was selected as a reporter because of its intrinsic visible fluorescence. The fortilin, TAT and GFP fusion protein were constructed. Their trans-membrane transportation efficiency and effects on immune response of shrimp were analyzed in vitro. Results showed that TAT peptide improved in vitro uptake of fortilin into the hemocytes and midgut of Litopenaeus vannamei. The phenoloxidase (PO) activity of hemocytes incubated with GFP-Fortilin or GFP-Fortilin-TAT was significantly increased compared with that in the control without expressed fortilin. The PO activity of hemocytes incubated with 200 μg mL-1 GFP-Fortilin-TAT was significantly higher than that in the group with the same concentration of GFP-Fortilin. Hemocytes incubated with GFP-Fortilin-TAT at all concentrations showed significantly higher nitric oxide synthase (NOS) activity than those in the control or in the GFP-Fortilin treatment. The present in vitro study indicated that TAT fusion protein improved the immune effect of fortilin.

Biocompatible anionic polymeric microspheres as priming delivery system for effetive HIV/AIDS Tat-based vaccines.

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Fausto Titti

Full Text Available Here we describe a prime-boost regimen of vaccination in Macaca fascicularis that combines priming with novel anionic microspheres designed to deliver the biologically active HIV-1 Tat protein and boosting with Tat in Alum. This regimen of immunization modulated the IgG subclass profile and elicited a balanced Th1-Th2 type of humoral and cellular responses. Remarkably, following intravenous challenge with SHIV89.6Pcy243, vaccinees significantly blunted acute viremia, as compared to control monkeys, and this control was associated with significantly lower CD4+ T cell depletion rate during the acute phase of infection and higher ability to resume the CD4+ T cell counts in the post-acute and chronic phases of infection. The long lasting control of viremia was associated with the persistence of high titers anti-Tat antibodies whose profile clearly distinguished vaccinees in controllers and viremics. Controllers, as opposed to vaccinated and viremic cynos, exhibited significantly higher pre-challenge antibody responses to peptides spanning the glutamine-rich and the RGD-integrin-binding regions of Tat. Finally, among vaccinees, titers of anti-Tat IgG1, IgG3 and IgG4 subclasses had a significant association with control of viremia in the acute and post-acute phases of infection. Altogether these findings indicate that the Tat/H1D/Alum regimen of immunization holds promise for next generation vaccines with Tat protein or other proteins for which maintenance of the native conformation and activity are critical for optimal immunogenicity. Our results also provide novel information on the role of anti-Tat responses in the prevention of HIV pathogenesis and for the design of new vaccine candidates.

Negotiation of intracellular membrane barriers by TAT-modified gold nanoparticles.

Science.gov (United States)

Krpetić, Zeljka; Saleemi, Samia; Prior, Ian A; Sée, Violaine; Qureshi, Rumana; Brust, Mathias

2011-06-28

This paper contributes to the debate on how nanosized objects negotiate membrane barriers inside biological cells. The uptake of peptide-modified gold nanoparticles by HeLa cells has been quantified using atomic emission spectroscopy. The TAT peptide from the HIV virus was singled out as a particularly effective promoter of cellular uptake. The evolution of the intracellular distribution of TAT-modified gold nanoparticles with time has been studied in detail by TEM and systematic image analysis. An unusual trend of particles disappearing from the cytosol and the nucleus and accumulating massively in vesicular bodies was observed. Subsequent release of the particles, both by membrane rupture and by direct transfer across the membrane boundary, was frequently found. Ultimately, near total clearing of particles from the cells occurred. This work provides support for the hypothesis that cell-penetrating peptides can enable small objects to negotiate membrane barriers also in the absence of dedicated transport mechanisms.

Adenovirus serotype 5 vectors with Tat-PTD modified hexon and serotype 35 fiber show greatly enhanced transduction capacity of primary cell cultures.

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Di Yu

Full Text Available Recombinant adenovirus serotype 5 (Ad5 vectors represent one of the most efficient gene delivery vectors in life sciences. However, Ad5 is dependent on expression of the coxsackievirus-adenovirus-receptor (CAR on the surface of target cell for efficient transduction, which limits it's utility for certain cell types. Herein we present a new vector, Ad5PTDf35, which is an Ad5 vector having serotype 35 fiber-specificity and Tat-PTD hexon-modification. This vector shows dramatically increased transduction capacity of primary human cell cultures including T cells, monocytes, macrophages, dendritic cells, pancreatic islets and exocrine cells, mesenchymal stem cells and tumor initiating cells. Biodistribution in mice following systemic administration (tail-vein injection show significantly reduced uptake in the liver and spleen of Ad5PTDf35 compared to unmodified Ad5. Therefore, replication-competent viruses with these modifications may be further developed as oncolytic agents for cancer therapy. User-friendly backbone plasmids containing these modifications were developed for compatibility to the AdEasy-system to facilitate the development of surface-modified adenoviruses for gene delivery to difficult-to-transduce cells in basic, pre-clinical and clinical research.

Effects of prostratin on Cyclin T1/P-TEFb function and the gene expression profile in primary resting CD4+ T cells

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Rice Andrew P

2006-10-01

Full Text Available Abstract Background The latent reservoir of human immunodeficiency virus type 1 (HIV-1 in resting CD4+ T cells is a major obstacle to the clearance of infection by highly active antiretroviral therapy (HAART. Recent studies have focused on searches for adjuvant therapies to activate this reservoir under conditions of HAART. Prostratin, a non tumor-promoting phorbol ester, is a candidate for such a strategy. Prostratin has been shown to reactivate latent HIV-1 and Tat-mediated transactivation may play an important role in this process. We examined resting CD4+ T cells from healthy donors to determine if prostratin induces Cyclin T1/P-TEFb, a cellular kinase composed of Cyclin T1 and Cyclin-dependent kinase-9 (CDK9 that mediates Tat function. We also examined effects of prostratin on Cyclin T2a, an alternative regulatory subunit for CDK9, and 7SK snRNA and the HEXIM1 protein, two factors that associate with P-TEFb and repress its kinase activity. Results Prostratin up-regulated Cyclin T1 protein expression, modestly induced CDK9 protein expression, and did not affect Cyclin T2a protein expression. Although the kinase activity of CDK9 in vitro was up-regulated by prostratin, we observed a large increase in the association of 7SK snRNA and the HEXIM1 protein with CDK9. Using HIV-1 reporter viruses with and without a functional Tat protein, we found that prostratin stimulation of HIV-1 gene expression appears to require a functional Tat protein. Microarray analyses were performed and several genes related to HIV biology, including APOBEC3B, DEFA1, and S100 calcium-binding protein genes, were found to be regulated by prostratin. Conclusion Prostratin induces Cyclin T1 expression and P-TEFb function and this is likely to be involved in prostratin reactivation of latent HIV-1 proviruses. The large increase in association of 7SK and HEXIM1 with P-TEFb following prostratin treatment may reflect a requirement in CD4+ T cells for a precise balance between

Tat-dependent repression of human immunodeficiency virus type 1 long terminal repeat promoter activity by fusion of cellular transcription factors

International Nuclear Information System (INIS)

Zhao Cunyou; Chen Yali; Park, Jiyoung; Kim, Jae Bum; Tang Hong

2004-01-01

Transcription initiation from HIV-1 long terminal repeat (LTR) promoter requires the virally encoded transactivator, Tat, and several cellular co-factors to accomplish the Tat-dependent processive transcription elongation. Individual cellular transcription activators, LBP-1b and Oct-1, on the other hand, have been shown to inhibit LTR promoter activities probably via competitive binding against TFIID to the TATA-box in LTR promoter. To explore the genetic interference strategies against the viral replication, we took advantage of the existence of the bipartite DNA binding domains and the repression domains of LBP-1b and Oct-1 factors to generate a chimeric transcription repressor. Our results indicated that the fusion protein of LBP-1b and Oct-1 exhibited higher DNA binding affinity to the viral promoter than the individual factors, and little interference with the host cell gene expression due to its anticipated rare cognate DNA sites in the host cell genome. Moreover, the chimera exerted increased Tat-dependent repression of transcription initiation at the LTR promoter both in vitro and in vivo compared to LBP-1b, Oct-1 or combination of LBP-1b and Oct-1. These results might provide the lead in generating a therapeutic reagent useful to suppress HIV-1 replication

Extensive interactions between HIV TAT and TAF(II)250.

Science.gov (United States)

Weissman, J D; Hwang, J R; Singer, D S

2001-03-09

The HIV transactivator, Tat, has been shown to be capable of potent repression of transcription initiation. Repression is mediated by the C-terminal segment of Tat, which binds the TFIID component, TAF(II)250, although the site(s) of interaction were not defined previously. We now report that the interaction between Tat and TAF(II)250 is extensive and involves multiple contacts between the Tat protein and TAF(II)250. The C-terminal domain of Tat, which is necessary for repression of transcription initiation, binds to a segment of TAF(II)250 that encompasses its acetyl transferase (AT) domain (885-1034 amino acids (aa)). Surprisingly, the N-terminal segment of Tat, which contains its activation domains, also binds to TAF(II)250 and interacts with two discontinuous segments of TAF(II)250 located between 885 and 984 aa and 1120 and 1279 aa. Binding of Tat to the 885-984 aa segment of TAF(II)250 requires the cysteine-rich domain of Tat, but not the acidic or glutamine-rich domains. Binding by the N-terminal domain of Tat to the 1120-1279 aa TAF(II)250 segment does not involve the acidic, cysteine- or glutamine-rich domains. Repression of transcription initiation by Tat requires functional TAF(II)250. We now demonstrate that transcription of the HIV LTR does not depend on TAF(II)250 which may account for its resistance to Tat mediated repression.

Antibodies to the HIV-1 Tat protein correlated with nonprogression to AIDS: a rationale for the use of Tat toxoid as an HIV-1 vaccine.

Science.gov (United States)

Zagury, J F; Sill, A; Blattner, W; Lachgar, A; Le Buanec, H; Richardson, M; Rappaport, J; Hendel, H; Bizzini, B; Gringeri, A; Carcagno, M; Criscuolo, M; Burny, A; Gallo, R C; Zagury, D

1998-01-01

To investigate which immune parameters, such as antibodies against HIV-1 specificities, or viral parameters, such as p24 antigenemia, are predictive of disease progression. We performed studies on serum collected from individuals exhibiting two extremes of disease evolution--67 fast progressors (FP) and 182 nonprogressors (NP)--at their enrollment. After a 1- to 2-year clinical follow-up of 104 nonprogressors after their enrollment, we could determine the best serologic predictors for disease progression. We investigated levels of antibodies to tetanus toxoid and to HIV antigens including Env, Gag, Nef, and Tat proteins, as well as p24 antigenemia, viremia, CD4 cell count, and interferon-alpha (IFN-alpha) titers in FPs and NPs, and we correlated these data with clinical and biologic signs of progression. p24 Antigenemia, a marker of viral replication, and anti-Tat antibodies were highly and inversely correlated in both groups (P < .001). Furthermore, anti-p24 antibodies and low serum IFN-alpha levels were correlated to the NP versus the FP cohort. Finally, among NPs, only antibodies to Tat and not to the other HIV specificities (Env, Nef, Gag) were significantly predictive of clinical stability during their follow-up. Antibodies toward HIV-1 Tat, which are inversely correlated to p24 antigenemia, appear as a critical marker for a lack of disease progression. This study strongly suggests that rising anti-Tat antibodies through active immunization may be beneficial in AIDS vaccine development to control viral replication.

A new fluorescence/PET probe for targeting intracellular human telomerase reverse transcriptase (hTERT) using Tat peptide-conjugated IgM

International Nuclear Information System (INIS)

Jung, Kyung oh; Youn, Hyewon; Kim, Seung Hoo; Kim, Young-Hwa; Kang, Keon Wook; Chung, June-Key

2016-01-01

Despite an increasing need for methods to visualize intracellular proteins in vivo, the majority of antibody-based imaging methods available can only detect membrane proteins. The human telomerase reverse transcriptase (hTERT) is an intracellular target of great interest because of its high expression in several types of cancer. In this study, we developed a new probe for hTERT using the Tat peptide. An hTERT antibody (IgG or IgM) was conjugated with the Tat peptide, a fluorescence dye and "6"4Cu. HT29 (hTERT+) and U2OS (hTERT−) were used to visualize the intracellular hTERT. The hTERT was detected by RT-PCR and western blot. Fluorescence signals for hTERT were obtained by confocal microscopy, live cell imaging, and analyzed by Tissue-FAXS. In nude mice, tumors were visualized using the fluorescence imaging devices Maestro™ and PETBOX. In RT-PCR and western blot, the expression of hTERT was detected in HT29 cells, but not in U2OS cells. Fluorescence signals were clearly observed in HT29 cells and in U2OS cells after 1 h of treatment, but signals were only detected in HT29 cells after 24 h. Confocal microscopy showed that 9.65% of U2OS and 78.54% of HT29 cells had positive hTERT signals. 3D animation images showed that the probe could target intranuclear hTERT in the nucleus. In mice models, fluorescence and PET imaging showed that hTERT in HT29 tumors could be efficiently visualized. In summary, we developed a new method to visualize intracellular and intranuclear proteins both in vitro and in vivo. - Highlights: • We developed new probes for imaging hTERT using Tat-conjugated IgM antibodies labeled with a fluorescent dye and radioisotope. • This probes could be used to overcome limitation of conventional antibody imaging system in live cell imaging. • This system could be applicable to monitor intracellular and intranuclear proteins in vitro and in vivo.

A new fluorescence/PET probe for targeting intracellular human telomerase reverse transcriptase (hTERT) using Tat peptide-conjugated IgM

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Jung, Kyung oh [Department of Nuclear Medicine, Seoul National University College of Medicine (Korea, Republic of); Biomedical Sciences, Seoul National University College of Medicine (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine (Korea, Republic of); Tumor Microenvironment Global Core Research Center, Seoul National University (Korea, Republic of); Youn, Hyewon, E-mail: hwyoun@snu.ac.kr [Department of Nuclear Medicine, Seoul National University College of Medicine (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine (Korea, Republic of); Tumor Microenvironment Global Core Research Center, Seoul National University (Korea, Republic of); Cancer Imaging Center, Seoul National University Hospital, Seoul (Korea, Republic of); Kim, Seung Hoo [Department of Nuclear Medicine, Seoul National University College of Medicine (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine (Korea, Republic of); Kim, Young-Hwa [Department of Nuclear Medicine, Seoul National University College of Medicine (Korea, Republic of); Biomedical Sciences, Seoul National University College of Medicine (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine (Korea, Republic of); Kang, Keon Wook [Department of Nuclear Medicine, Seoul National University College of Medicine (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine (Korea, Republic of); Chung, June-Key, E-mail: jkchung@snu.ac.kr [Department of Nuclear Medicine, Seoul National University College of Medicine (Korea, Republic of); Biomedical Sciences, Seoul National University College of Medicine (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine (Korea, Republic of); Tumor Microenvironment Global Core Research Center, Seoul National University (Korea, Republic of)

2016-08-26

Despite an increasing need for methods to visualize intracellular proteins in vivo, the majority of antibody-based imaging methods available can only detect membrane proteins. The human telomerase reverse transcriptase (hTERT) is an intracellular target of great interest because of its high expression in several types of cancer. In this study, we developed a new probe for hTERT using the Tat peptide. An hTERT antibody (IgG or IgM) was conjugated with the Tat peptide, a fluorescence dye and {sup 64}Cu. HT29 (hTERT+) and U2OS (hTERT−) were used to visualize the intracellular hTERT. The hTERT was detected by RT-PCR and western blot. Fluorescence signals for hTERT were obtained by confocal microscopy, live cell imaging, and analyzed by Tissue-FAXS. In nude mice, tumors were visualized using the fluorescence imaging devices Maestro™ and PETBOX. In RT-PCR and western blot, the expression of hTERT was detected in HT29 cells, but not in U2OS cells. Fluorescence signals were clearly observed in HT29 cells and in U2OS cells after 1 h of treatment, but signals were only detected in HT29 cells after 24 h. Confocal microscopy showed that 9.65% of U2OS and 78.54% of HT29 cells had positive hTERT signals. 3D animation images showed that the probe could target intranuclear hTERT in the nucleus. In mice models, fluorescence and PET imaging showed that hTERT in HT29 tumors could be efficiently visualized. In summary, we developed a new method to visualize intracellular and intranuclear proteins both in vitro and in vivo. - Highlights: • We developed new probes for imaging hTERT using Tat-conjugated IgM antibodies labeled with a fluorescent dye and radioisotope. • This probes could be used to overcome limitation of conventional antibody imaging system in live cell imaging. • This system could be applicable to monitor intracellular and intranuclear proteins in vitro and in vivo.

Contribution of nonneutralizing vaccine-elicited antibody activities to improved protective efficacy in rhesus macaques immunized with Tat/Env compared with multigenic vaccines.

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Florese, Ruth H; Demberg, Thorsten; Xiao, Peng; Kuller, LaRene; Larsen, Kay; Summers, L Ebonita; Venzon, David; Cafaro, Aurelio; Ensoli, Barbara; Robert-Guroff, Marjorie

2009-03-15

Previously, chronic-phase protection against SHIV(89.6P) challenge was significantly greater in macaques primed with replicating adenovirus type 5 host range mutant (Ad5hr) recombinants encoding HIVtat and env and boosted with Tat and Env protein compared with macaques primed with multigenic adenovirus recombinants (HIVtat, HIVenv, SIVgag, SIVnef) and boosted with Tat, Env, and Nef proteins. The greater protection was correlated with Tat- and Env-binding Abs. Because the macaques lacked SHIV(89.6P)-neutralizing activity prechallenge, we investigated whether Ab-dependent cellular cytotoxicity (ADCC) and Ab-dependent cell-mediated viral inhibition (ADCVI) might exert a protective effect. We clearly show that Tat can serve as an ADCC target, although the Tat-specific activity elicited did not correlate with better protection. However, Env-specific ADCC activity was consistently higher in the Tat/Env group, with sustained cell killing postchallenge exhibited at higher levels (p vaccine regimens.

Anti-inflammatory effects of Tat-Annexin protein on ovalbumin-induced airway inflammation in a mouse model of asthma

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Lee, Sun Hwa; Kim, Dae Won; Kim, Hye Ri; Woo, Su Jung; Kim, So Mi; Jo, Hyo Sang [Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chunchon 200-702 (Korea, Republic of); Jeon, Seong Gyu [Department of Life Science, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Cho, Sung-Woo [Department of Biochemistry and Molecular Biology, University of Ulsan, College of Medicine, Seoul 138-736 (Korea, Republic of); Park, Jong Hoon [Department of Biological Science, Sookmyung Women' s University, Seoul 140-742 (Korea, Republic of); Won, Moo Ho [Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 200-701 (Korea, Republic of); Park, Jinseu [Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chunchon 200-702 (Korea, Republic of); Eum, Won Sik, E-mail: wseum@hallym.ac.kr [Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chunchon 200-702 (Korea, Republic of); Choi, Soo Young, E-mail: sychoi@hallym.ac.kr [Department of Biomedical Science and Research Institute of Bioscience and Biotechnology, Hallym University, Chunchon 200-702 (Korea, Republic of)

2012-01-20

Highlights: Black-Right-Pointing-Pointer We construct a cell permeable Tat-ANX1 fusion protein. Black-Right-Pointing-Pointer We examined the protective effects of Tat-ANX1 protein on OVA-induced asthma in animal models. Black-Right-Pointing-Pointer Transduced Tat-ANX1 protein protects from the OVA-induced production of cytokines and eosinophils in BAL fluid. Black-Right-Pointing-Pointer Tat-ANX1 protein markedly reduced OVA-induced MAPK in lung tissues. Black-Right-Pointing-Pointer Tat-ANX1 protein could be useful as a therapeutic agent for lung disorders including asthma. -- Abstract: Chronic airway inflammation is a key feature of bronchial asthma. Annexin-1 (ANX1) is an anti-inflammatory protein that is an important modulator and plays a key role in inflammation. Although the precise action of ANX1 remains unclear, it has emerged as a potential drug target for inflammatory diseases such as asthma. To examine the protective effects of ANX1 protein on ovalbumin (OVA)-induced asthma in animal models, we used a cell-permeable Tat-ANX1 protein. Mice sensitized and challenged with OVA antigen had an increased amount of cytokines and eosinophils in their bronchoalveolar lavage (BAL) fluid. However, administration of Tat-ANX1 protein before OVA challenge significantly decreased the levels of cytokines (interleukin (IL)-4, IL-5, and IL-13) and BAL fluid in lung tissues. Furthermore, OVA significantly increased the activation of mitogen-activated protein kinase (MAPK) in lung tissues, whereas Tat-ANX1 protein markedly reduced phosphorylation of MAPKs such as extracellular signal-regulated protein kinase, p38, and stress-activated protein kinase/c-Jun N-terminal kinase. These results suggest that transduced Tat-ANX1 protein may be a potential protein therapeutic agent for the treatment of lung disorders including asthma.

Cell-permeable intrinsic cellular inhibitors of apoptosis protect and rescue intestinal epithelial cells from radiation-induced cell death

International Nuclear Information System (INIS)

Matsuzaki-Horibuchi, Shiori; Yasuda, Takeshi; Sakaguchi, Nagako; Yamaguchi, Yoshihiro; Akashi, Makoto

2015-01-01

One of the important mechanisms for gastrointestinal (GI) injury following high-dose radiation exposure is apoptosis of epithelial cells. X-linked inhibitor of apoptosis (XIAP) and cellular IAP2 (cIAP2) are intrinsic cellular inhibitors of apoptosis. In order to study the effects of exogenously added IAPs on apoptosis in intestinal epithelial cells, we constructed bacterial expression plasmids containing genes of XIAP (full-length, BIR2 domain and BIR3-RING domain with and without mutations of auto-ubiquitylation sites) and cIAP2 proteins fused to a protein-transduction domain (PTD) derived from HIV-1 Tat protein (TAT) and purified these cell-permeable recombinant proteins. When the TAT-conjugated IAPs were added to rat intestinal epithelial cells IEC6, these proteins were effectively delivered into the cells and inhibited apoptosis, even when added after irradiation. Our results suggest that PTD-mediated delivery of IAPs may have clinical potential, not only for radioprotection but also for rescuing the GI system from radiation injuries. (author)

Interaction of the protein transduction domain of HIV-1 TAT with heparan sulfate: binding mechanism and thermodynamic parameters.

Science.gov (United States)

Ziegler, André; Seelig, Joachim

2004-01-01

The positively charged protein transduction domain of the HIV-1 TAT protein (TAT-PTD; residues 47-57 of TAT) rapidly translocates across the plasma membrane of living cells. This property is exploited for the delivery of proteins, drugs, and genes into cells. The mechanism of this translocation is, however, not yet understood. Recent theories for translocation suggest binding of the protein transduction domain (PTD) to extracellular glycosaminoglycans as a possible mechanism. We have studied the binding equilibrium between TAT-PTD and three different glycosaminoglycans with high sensitivity isothermal titration calorimetry and provide the first quantitative thermodynamic description. The polysulfonated macromolecules were found to exhibit multiple identical binding sites for TAT-PTD with only small differences between the three species as far as the thermodynamic parameters are concerned. Heparan sulfate (HS, molecular weight, 14.2 +/- 2 kDa) has 6.3 +/- 1.0 independent binding sites for TAT-PTD which are characterized by a binding constant K0 = (6.0 +/- 0.6) x 10(5) M(-1) and a reaction enthalpy deltaHpep0 = -4.6 +/- 1.0 kcal/mol at 28 degrees C. The binding affinity, deltaGpep0, is determined to equal extent by enthalpic and entropic contributions. The HS-TAT-PTD complex formation entails a positive heat capacity change of deltaCp0 = +135 cal/mol peptide, which is characteristic of a charge neutralization reaction. This is in contrast to hydrophobic binding reactions which display a large negative heat capacity change. The stoichiometry of 6-7 TAT-PTD molecules per HS corresponds to an electric charge neutralization. Light scattering data demonstrate a maximum scattering intensity at this stoichiometric ratio, the intensity of which depends on the order of mixing of the two components. The data suggest cross-linking and/or aggregation of HS-TAT-PTD complexes. Two other glycosaminoglycans, namely heparin and chondroitin sulfate B, were also studied with isothermal

Human immunodeficiency virus-1 protein Tat induces excitotoxic loss of presynaptic terminals in hippocampal cultures.

Science.gov (United States)

Shin, Angela H; Thayer, Stanley A

2013-05-01

Human immunodeficiency virus (HIV) infection of the CNS produces dendritic damage that correlates with cognitive decline in patients with HIV-associated neurocognitive disorders (HAND). HIV-induced neurotoxicity results in part from viral proteins shed from infected cells, including the HIV transactivator of transcription (Tat). We previously showed that Tat binds to the low density lipoprotein receptor-related protein (LRP), resulting in overactivation of NMDA receptors, activation of the ubiquitin-proteasome pathway, and subsequent loss of postsynaptic densities. Here, we show that Tat also induces a loss of presynaptic terminals. The number of presynaptic terminals was quantified using confocal imaging of synaptophysin fused to green fluorescent protein (Syn-GFP). Tat-induced loss of presynaptic terminals was secondary to excitatory postsynaptic mechanisms because treatment with an LRP antagonist or an NMDA receptor antagonist inhibited this loss. Treatment with nutlin-3, an E3 ligase inhibitor, prevented Tat-induced loss of presynaptic terminals. These data suggest that Tat-induced loss of presynaptic terminals is a consequence of excitotoxic postsynaptic activity. We previously found that ifenprodil, an NR2B subunit-selective NMDA receptor antagonist, induced recovery of postsynaptic densities. Here we show that Tat-induced loss of presynaptic terminals was reversed by ifenprodil treatment. Thus, Tat-induced loss of presynaptic terminals is reversible, and this recovery can be initiated by inhibiting a subset of postsynaptic NMDA receptors. Understanding the dynamics of synaptic changes in response to HIV infection of the CNS may lead to the design of improved pharmacotherapies for HAND patients. Copyright © 2012 Elsevier Inc. All rights reserved.

The neuroprotective efficacy of cell-penetrating peptides TAT, penetratin, Arg-9, and Pep-1 in glutamic acid, kainic acid, and in vitro ischemia injury models using primary cortical neuronal cultures.

Science.gov (United States)

Meloni, Bruno P; Craig, Amanda J; Milech, Nadia; Hopkins, Richard M; Watt, Paul M; Knuckey, Neville W

2014-03-01

Cell-penetrating peptides (CPPs) are small peptides (typically 5-25 amino acids), which are used to facilitate the delivery of normally non-permeable cargos such as other peptides, proteins, nucleic acids, or drugs into cells. However, several recent studies have demonstrated that the TAT CPP has neuroprotective properties. Therefore, in this study, we assessed the TAT and three other CPPs (penetratin, Arg-9, Pep-1) for their neuroprotective properties in cortical neuronal cultures following exposure to glutamic acid, kainic acid, or in vitro ischemia (oxygen-glucose deprivation). Arg-9, penetratin, and TAT-D displayed consistent and high level neuroprotective activity in both the glutamic acid (IC50: 0.78, 3.4, 13.9 μM) and kainic acid (IC50: 0.81, 2.0, 6.2 μM) injury models, while Pep-1 was ineffective. The TAT-D isoform displayed similar efficacy to the TAT-L isoform in the glutamic acid model. Interestingly, Arg-9 was the only CPP that displayed efficacy when washed-out prior to glutamic acid exposure. Neuroprotection following in vitro ischemia was more variable with all peptides providing some level of neuroprotection (IC50; Arg-9: 6.0 μM, TAT-D: 7.1 μM, penetratin/Pep-1: >10 μM). The positive control peptides JNKI-1D-TAT (JNK inhibitory peptide) and/or PYC36L-TAT (AP-1 inhibitory peptide) were neuroprotective in all models. Finally, in a post-glutamic acid treatment experiment, Arg-9 was highly effective when added immediately after, and mildly effective when added 15 min post-insult, while the JNKI-1D-TAT control peptide was ineffective when added post-insult. These findings demonstrate that different CPPs have the ability to inhibit neurodamaging events/pathways associated with excitotoxic and ischemic injuries. More importantly, they highlight the need to interpret neuroprotection studies when using CPPs as delivery agents with caution. On a positive note, the cytoprotective properties of CPPs suggests they are ideal carrier molecules to

MD simulation of the Tat/Cyclin T1/CDK9 complex revealing the hidden catalytic cavity within the CDK9 molecule upon Tat binding.

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Kaori Asamitsu

Full Text Available In this study, we applied molecular dynamics (MD simulation to analyze the dynamic behavior of the Tat/CycT1/CDK9 tri-molecular complex and revealed the structural changes of P-TEFb upon Tat binding. We found that Tat could deliberately change the local flexibility of CycT1. Although the structural coordinates of the H1 and H2 helices did not substantially change, H1', H2', and H3' exhibited significant changes en masse. Consequently, the CycT1 residues involved in Tat binding, namely Tat-recognition residues (TRRs, lost their flexibility with the addition of Tat to P-TEFb. In addition, we clarified the structural variation of CDK9 in complex with CycT1 in the presence or absence of Tat. Interestingly, Tat addition significantly reduced the structural variability of the T-loop, thus consolidating the structural integrity of P-TEFb. Finally, we deciphered the formation of the hidden catalytic cavity of CDK9 upon Tat binding. MD simulation revealed that the PITALRE signature sequence of CDK9 flips the inactive kinase cavity of CDK9 into the active form by connecting with Thr186, which is crucial for its activity, thus presumably recruiting the substrate peptide such as the C-terminal domain of RNA pol II. These findings provide vital information for the development of effective novel anti-HIV drugs with CDK9 catalytic activity as the target.

An attenuated herpes simplex virus type 1 (HSV1 encoding the HIV-1 Tat protein protects mice from a deadly mucosal HSV1 challenge.

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Mariaconcetta Sicurella

Full Text Available Herpes simplex virus types 1 and 2 (HSV1 and HSV2 are common infectious agents in both industrialized and developing countries. They cause recurrent asymptomatic and/or symptomatic infections, and life-threatening diseases and death in newborns and immunocompromised patients. Current treatment for HSV relies on antiviral medications, which can halt the symptomatic diseases but cannot prevent the shedding that occurs in asymptomatic patients or, consequently, the spread of the viruses. Therefore, prevention rather than treatment of HSV infections has long been an area of intense research, but thus far effective anti-HSV vaccines still remain elusive. One of the key hurdles to overcome in anti-HSV vaccine development is the identification and effective use of strategies that promote the emergence of Th1-type immune responses against a wide range of epitopes involved in the control of viral replication. Since the HIV1 Tat protein has several immunomodulatory activities and increases CTL recognition of dominant and subdominant epitopes of heterologous antigens, we generated and assayed a recombinant attenuated replication-competent HSV1 vector containing the tat gene (HSV1-Tat. In this proof-of-concept study we show that immunization with this vector conferred protection in 100% of mice challenged intravaginally with a lethal dose of wild-type HSV1. We demonstrate that the presence of Tat within the recombinant virus increased and broadened Th1-like and CTL responses against HSV-derived T-cell epitopes and elicited in most immunized mice detectable IgG responses. In sharp contrast, a similarly attenuated HSV1 recombinant vector without Tat (HSV1-LacZ, induced low and different T cell responses, no measurable antibody responses and did not protect mice against the wild-type HSV1 challenge. These findings strongly suggest that recombinant HSV1 vectors expressing Tat merit further investigation for their potential to prevent and/or contain HSV1

An attenuated herpes simplex virus type 1 (HSV1) encoding the HIV-1 Tat protein protects mice from a deadly mucosal HSV1 challenge.

Science.gov (United States)

Sicurella, Mariaconcetta; Nicoli, Francesco; Gallerani, Eleonora; Volpi, Ilaria; Berto, Elena; Finessi, Valentina; Destro, Federica; Manservigi, Roberto; Cafaro, Aurelio; Ensoli, Barbara; Caputo, Antonella; Gavioli, Riccardo; Marconi, Peggy C

2014-01-01

Herpes simplex virus types 1 and 2 (HSV1 and HSV2) are common infectious agents in both industrialized and developing countries. They cause recurrent asymptomatic and/or symptomatic infections, and life-threatening diseases and death in newborns and immunocompromised patients. Current treatment for HSV relies on antiviral medications, which can halt the symptomatic diseases but cannot prevent the shedding that occurs in asymptomatic patients or, consequently, the spread of the viruses. Therefore, prevention rather than treatment of HSV infections has long been an area of intense research, but thus far effective anti-HSV vaccines still remain elusive. One of the key hurdles to overcome in anti-HSV vaccine development is the identification and effective use of strategies that promote the emergence of Th1-type immune responses against a wide range of epitopes involved in the control of viral replication. Since the HIV1 Tat protein has several immunomodulatory activities and increases CTL recognition of dominant and subdominant epitopes of heterologous antigens, we generated and assayed a recombinant attenuated replication-competent HSV1 vector containing the tat gene (HSV1-Tat). In this proof-of-concept study we show that immunization with this vector conferred protection in 100% of mice challenged intravaginally with a lethal dose of wild-type HSV1. We demonstrate that the presence of Tat within the recombinant virus increased and broadened Th1-like and CTL responses against HSV-derived T-cell epitopes and elicited in most immunized mice detectable IgG responses. In sharp contrast, a similarly attenuated HSV1 recombinant vector without Tat (HSV1-LacZ), induced low and different T cell responses, no measurable antibody responses and did not protect mice against the wild-type HSV1 challenge. These findings strongly suggest that recombinant HSV1 vectors expressing Tat merit further investigation for their potential to prevent and/or contain HSV1 infection and

Inhibition of GABAergic Neurotransmission by HIV-1 Tat and Opioid Treatment in the Striatum Involves μ-opioid Receptors

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Changqing Xu

2016-11-01

Full Text Available Due to combined antiretroviral therapy (cART, human immunodeficiency virus type 1 (HIV-1 is considered a chronic disease with high prevalence of mild forms of neurocognitive impairments, also referred to as HIV-associated neurocognitive disorders (HAND. Although opiate drug use can exacerbate HIV-1 Tat-induced neuronal damage, it remains unknown how and to what extent opioids interact with Tat on the GABAergic system. We conducted whole-cell recordings in mouse striatal slices and examined the effects of HIV-1 Tat in the presence and absence of morphine (1 μM and damgo (1 μM on GABAergic neurotransmission. Results indicated a decrease in the frequency and amplitude of spontaneous inhibitory postsynaptic currents (sIPSCs and miniature IPSCs (mIPSCs by Tat (5 – 50 nM in a concentration-dependent manner. The significant Tat-induced decrease in IPSCs was abolished when removing extracellular and/or intracellular calcium. Treatment with morphine or damgo alone significantly decreased the frequency, but not amplitude of IPSCs. Interestingly, morphine but not damgo indicated an additional downregulation of the mean frequency of mIPSCs in combination with Tat. Pretreatment with naloxone (1 μM and CTAP (1 μM prevented the Tat-induced decrease in sIPSCs frequency but only naloxone prevented the combined Tat and morphine effect on mIPSCs frequency. Results indicate a Tat- or opioid-induced decrease in GABAergic neurotransmission via µ-opioid receptors with combined Tat and morphine effects involving additional opioid receptor-related mechanisms. Exploring the interactions between Tat and opioids on the GABAergic system may help to guide future research on HAND in the context of opiate drug use.

Die TAT-Z as voorspeller vir prestasiemotivering

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F. V. N. Cilliers

1979-11-01

Die gebruik van die TAT-Z, 'n projeksietoets vir Swartmans, word ondersoek om prestasiemotivering veral tydens die indiensnemingsituasie te voorspel. Positiewe resultate is op 3 van die 10 kaarte (nrs. 4, 6 en 9 van die TAT-Z verkry. Aanbevelings word gemaak aangaande die aanpassing van hierdie projeksietoets ten einde meer inligting oor prestasiemotivering, bloot te lê.

"cART intensification by the HIV-1 Tat B clade vaccine: progress to phase III efficacy studies".

Science.gov (United States)

Cafaro, Aurelio; Sgadari, Cecilia; Picconi, Orietta; Tripiciano, Antonella; Moretti, Sonia; Francavilla, Vittorio; Pavone Cossut, Maria Rosaria; Buttò, Stefano; Cozzone, Giovanni; Ensoli, Fabrizio; Monini, Paolo; Ensoli, Barbara

2018-02-01

In spite of its success at suppressing HIV replication, combination antiretroviral therapy (cART) only partially reduces immune dysregulation and loss of immune functions. These cART-unmet needs appear to be due to persistent virus replication and cell-to-cell transmission in reservoirs, and are causes of increased patients' morbidity and mortality. Up to now, therapeutic interventions aimed at cART-intensification by attacking the virus reservoir have failed. Areas covered: We briefly review the rationale and clinical development of Tat therapeutic vaccine in cART-treated subjects in Italy and South Africa (SA). Vaccination with clade-B Tat induced cross-clade neutralizing antibodies, immune restoration, including CD4 + T cell increase particularly in low immunological responders, and reduction of proviral DNA. Phase III efficacy trials in SA are planned both in adult and pediatric populations. Expert commentary: We propose the Tat therapeutic vaccine as a pathogenesis-driven intervention that effectively intensifies cART and may lead to a functional cure and provide new perspectives for prevention and virus eradication strategies.

Nonlatching positive feedback enables robust bimodality by decoupling expression noise from the mean

Energy Technology Data Exchange (ETDEWEB)

Razooky, Brandon S. [Rockefeller Univ., New York, NY (United States). Lab. of Virology and Infectious Disease; Gladstone Institutes (Virology and Immunology), San Francisco, CA (United States); Univ. of California, San Francisco, CA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Univ. of Tennessee, Knoxville, TN (United States). Bredesen Center for Interdisciplinary; Cao, Youfang [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hansen, Maike M. K. [Gladstone Institutes (Virology and Immunology), San Francisco, CA (United States); Perelson, Alan S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Simpson, Michael L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Univ. of Tennessee, Knoxville, TN (United States). Bredesen Center for Interdisciplinary; Weinberger, Leor S. [Gladstone Institutes (Virology and Immunology), San Francisco, CA (United States); Univ. of California, San Francisco, CA (United States). Dept. of Biochemistry and Biophysics; Univ. of California, San Francisco, CA (United States). QB3: California Inst. of Quantitative Biosciences; Univ. of California, San Francisco, CA (United States). Dept. of Pharmaceutical Chemistry

2017-10-18

Fundamental to biological decision-making is the ability to generate bimodal expression patterns where two alternate expression states simultaneously exist. Here in this study, we use a combination of single-cell analysis and mathematical modeling to examine the sources of bimodality in the transcriptional program controlling HIV’s fate decision between active replication and viral latency. We find that the HIV Tat protein manipulates the intrinsic toggling of HIV’s promoter, the LTR, to generate bimodal ON-OFF expression, and that transcriptional positive feedback from Tat shifts and expands the regime of LTR bimodality. This result holds for both minimal synthetic viral circuits and full-length virus. Strikingly, computational analysis indicates that the Tat circuit’s non-cooperative ‘non-latching’ feedback architecture is optimized to slow the promoter’s toggling and generate bimodality by stochastic extinction of Tat. In contrast to the standard Poisson model, theory and experiment show that non-latching positive feedback substantially dampens the inverse noise-mean relationship to maintain stochastic bimodality despite increasing mean-expression levels. Given the rapid evolution of HIV, the presence of a circuit optimized to robustly generate bimodal expression appears consistent with the hypothesis that HIV’s decision between active replication and latency provides a viral fitness advantage. More broadly, the results suggest that positive-feedback circuits may have evolved not only for signal amplification but also for robustly generating bimodality by decoupling expression fluctuations (noise) from mean expression levels.

T-cell responses targeting HIV Nef uniquely correlate with infected cell frequencies after long-term antiretroviral therapy.

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Allison S Thomas

2017-09-01

Full Text Available HIV-specific CD8+ T-cell responses limit viral replication in untreated infection. After the initiation of antiretroviral therapy (ART, these responses decay and the infected cell population that remains is commonly considered to be invisible to T-cells. We hypothesized that HIV antigen recognition may persist in ART-treated individuals due to low-level or episodic protein expression. We posited that if persistent recognition were occurring it would be preferentially directed against the early HIV gene products Nef, Tat, and Rev as compared to late gene products, such as Gag, Pol, and Env, which have higher barriers to expression. Using a primary cell model of latency, we observed that a Nef-specific CD8+ T-cell clone exhibited low-level recognition of infected cells prior to reactivation and robust recognition shortly thereafter. A Gag-specific CD8+ T-cell clone failed to recognized infected cells under these conditions, corresponding with a lack of detectable Gag expression. We measured HIV-specific T-cell responses in 96 individuals who had been suppressed on ART for a median of 7 years, and observed a significant, direct correlation between cell-associated HIV DNA levels and magnitudes of IFN-γ-producing Nef/Tat/Rev-specific T-cell responses. This correlation was confirmed in an independent cohort (n = 18. Correlations were not detected between measures of HIV persistence and T-cell responses to other HIV antigens. The correlation with Nef/Tat/Rev-specific T-cells was attributable to Nef-specific responses, the breadth of which also correlated with HIV DNA levels. These results suggest that ongoing Nef expression in ART-treated individuals drives preferential maintenance and/or expansion of T-cells reactive to this protein, implying sensing of infected cells by the immune system. The direct correlation, however, suggests that recognition does not result in efficient elimination of infected cells. These results raise the possibility that

Inhibition of GABAergic Neurotransmission by HIV-1 Tat and Opioid Treatment in the Striatum Involves ?-Opioid Receptors

OpenAIRE

Xu, Changqing; Fitting, Sylvia

2016-01-01

Due to combined antiretroviral therapy (cART), human immunodeficiency virus type 1 (HIV-1) is considered a chronic disease with high prevalence of mild forms of neurocognitive impairments, also referred to as HIV-associated neurocognitive disorders (HAND). Although opiate drug use can exacerbate HIV-1 Tat-induced neuronal damage, it remains unknown how and to what extent opioids interact with Tat on the GABAergic system. We conducted whole-cell recordings in mouse striatal slices and examined...

Tat-haFGF14–154 Upregulates ADAM10 to Attenuate the Alzheimer Phenotype of APP/PS1 Mice through the PI3K-CREB-IRE1α/XBP1 Pathway

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Tian Meng

2017-06-01

Full Text Available Acid fibroblast growth factor (aFGF has shown neuroprotection in Alzheimer’s disease (AD models in previous studies, yet its mechanism is still uncertain. Here we report that the efficacy of Tat-haFGF14–154 is markedly increased when loaded cationic liposomes for intranasal delivery are intranasally administered to APP/PS1 mice. Our results demonstrated that liposomal Tat-haFGF14–154 treatment significantly ameliorated behavioral deficits, relieved brain Aβ burden, and increased the expression and activity of disintegrin and metalloproteinase domain-containing protein 10 (ADAM10 in the brain. Tat-haFGF14–154 antagonized Aβ1–42-induced cell death and structural damage in rat primary neurons in an ADAM10-dependent manner, which, in turn, was promoted by the activation of XBP1 splicing and modulated by the PI3K-CREB pathway. Both knockdown of ADAM10 and inhibition of PI3K (LY294002 negated Tat-haFGF14–154 rescue. Thus, Tat-haFGF14–154 activates the IRE1α/XBP1 pathway of the unfolded protein response (UPR against the endoplasmic reticulum (ER stress induced by Aβ, and, subsequently, the nuclear translocation of spliced XBP1 (XBP1s promotes transcription of ADAM10. These results highlight the important role of ADAM10 and its activation through the PI3K-CREB-IRE1α/XBP1 pathway as a key factor in the mechanism of neuroprotection for Tat-haFGF14–154.

Development and characterization of chitosan-PEG-TAT nanoparticles for the intracellular delivery of siRNA

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Malhotra M

2013-05-01

Full Text Available Meenakshi Malhotra,1 Catherine Tomaro-Duchesneau,1 Shyamali Saha,2 Imen Kahouli,3 Satya Prakash11Biomedical Technology and Cell Therapy Research Laboratory, Department of Biomedical Engineering, Faculty of Medicine, 2Faculty of Dentistry, 3Department of Experimental Medicine, McGill University, Montreal, QC, CanadaAbstract: Recently, cell-penetrating peptides have been proposed to translocate antibodies, proteins, and other molecules in targeted drug delivery. The proposed study presents the synthesis and characterization of a peptide-based chitosan nanoparticle for small interfering RNA (siRNA delivery, in-vitro. Specifically, the synthesis included polyethylene glycol (PEG, a hydrophilic polymer, and trans-activated transcription (TAT peptide, which were chemically conjugated on the chitosan polymer. The conjugation was achieved using N-Hydroxysuccinimide-PEG-maleimide (heterobifunctional PEG as a cross-linker, with the bifunctional PEG facilitating the amidation reaction through its N-Hydroxysuccinimide group and reacting with the amines on chitosan. At the other end of PEG, the maleimide group was chemically conjugated with the cysteine-modified TAT peptide. The degree of substitution on chitosan with PEG and on PEG with TAT was confirmed using colorimetric assays. The resultant polymer was used to form nanoparticles complexing siRNA, which were then characterized for particle size, morphology, cellular uptake, and cytotoxicity. The nanoparticles were tested in-vitro on mouse neuroblastoma cells (Neuro2a. Particle size and surface charge were characterized and an optimal pH condition and PEG molecular weight were determined to form sterically stable nanoparticles. Results indicate 7.5% of the amines in chitosan polymer were conjugated to the PEG and complete conjugation of TAT peptide was observed on the synthesized PEGylated chitosan polymer. Compared with unmodified chitosan nanoparticles, the nanoparticles formed at pH 6 were

Poly(ADP-ribose) polymerase inhibitors suppress UV-induced human immunodeficiency virus type 1 gene expression at the posttranscriptional level

International Nuclear Information System (INIS)

Yamagoe, S.; Kohda, T.; Oishi, M.

1991-01-01

Gene expression of human immunodeficiency virus type 1 (HIV-1) is induced not only by trans activation mediated through a gene product (tat) encoded by the virus but also by treatment of virus-carrying cells with DNA-damaging agents such as UV light. Employing an artificially constructed DNA in which the chloramphenicol acetyltransferase gene was placed under the control of the HIV-1 long terminal repeat, we analyzed the induction process in HeLa cells and found that inhibitors of poly(ADP-ribose) polymerase suppressed UV-induced HIV-1 gene expression but not tat-mediated expression. We also found that suppression occurs at the posttranscriptional level. These results indicate that HIV-1 gene expression is activated by at least two different mechanisms, one of which involves poly-ADP ribosylation. A possible new role of poly-ADP ribosylation in the regulation of specific gene expression is also discussed

Competition between Sec- and TAT-dependent protein translocation in Escherichia coli

DEFF Research Database (Denmark)

Cristóbal, S.; de Gier, J.-W.; Nielsen, Henrik

1999-01-01

-routed into the TAT pathway, suggesting that Sec-targeting signals in Lep can override TAT-targeting information in the TorA signal peptide. We also show that the TorA signal peptide can be converted into a Sec-targeting signal peptide by increasing the hydrophobicity of its h-region. Thus, beyond the twin...... the TorA TAT-targeting signal peptide to the Sec-dependent inner membrane protein leader peptidase (Lep). We find that the soluble, periplasmic P2 domain from Lep is re-routed by the TorA signal peptide into the TAT pathway. In contrast, the full-length TorA–Lep fusion protein is not re...

Systematic Analysis of the Functions of Lysine Acetylation in the Regulation of Tat Activity.

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Minghao He

Full Text Available The Tat protein of HIV-1 has several well-known properties, such as nucleocytoplasmic trafficking, transactivation of transcription, interaction with tubulin, regulation of mitotic progression, and induction of apoptosis. Previous studies have identified a couple of lysine residues in Tat that are essential for its functions. In order to analyze the functions of all the lysine residues in Tat, we mutated them individually to alanine, glutamine, and arginine. Through systematic analysis of the lysine mutants, we discovered several previously unidentified characteristics of Tat. We found that lysine acetylation could modulate the subcellular localization of Tat, in addition to the regulation of its transactivation activity. Our data also revealed that lysine mutations had distinct effects on microtubule assembly and Tat binding to bromodomain proteins. By correlation analysis, we further found that the effects of Tat on apoptosis and mitotic progression were not entirely attributed to its effect on microtubule assembly. Our findings suggest that Tat may regulate diverse cellular activities through binding to different proteins and that the acetylation of distinct lysine residues in Tat may modulate its interaction with various partners.

Neuroprotective effect of TAT-14-3-3ε fusion protein against cerebral ischemia/reperfusion injury in rats.

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Yuanjun Zhu

Full Text Available Stroke is the major cause of death and disability worldwide, and the thrombolytic therapy currently available was unsatisfactory. 14-3-3ε is a well characterized member of 14-3-3 family, and has been reported to protect neurons against apoptosis in cerebral ischemia. However, it cannot transverse blood brain barrier (BBB due to its large size. A protein transduction domain (PTD of HIV TAT protein, is capable of delivering a large variety of proteins into the brain. In this study, we generated a fusion protein TAT-14-3-3ε, and evaluated its potential neuroprotective effect in rat focal ischemia/reperfusion (I/R model. Western blot analysis validated the efficient transduction of TAT-14-3-3ε fusion protein into brain via a route of intravenous injection. TAT-14-3-3ε pre-treatment 2 h before ischemia significantly reduced cerebral infarction volume and improved neurologic score, while post-treatment 2 h after ischemia was less effective. Importantly, pre- or post-ischemic treatment with TAT-14-3-3ε significantly increased the number of surviving neurons as determined by Nissl staining, and attenuated I/R-induced neuronal apoptosis as showed by the decrease in apoptotic cell numbers and the inhibition of caspase-3 activity. Moreover, the introduction of 14-3-3ε into brain by TAT-mediated delivering reduced the formation of autophagosome, attenuated LC3B-II upregulation and reversed p62 downregulation induced by ischemic injury. Such inhibition of autophagy was reversed by treatment with an autophagy inducer rapamycin (RAP, which also attenuated the neuroprotective effect of TAT-14-3-3ε. Conversely, autophagy inhibitor 3-methyladenine (3-MA inhibited I/R-induced the increase in autophagic activity, and attenuated I/R-induced brain infarct. These results suggest that TAT-14-3-3ε can be efficiently transduced into brain and exert significantly protective effect against brain ischemic injury through inhibiting neuronal apoptosis and autophagic

The cross-talk of HIV-1 Tat and methamphetamine in HIV-associated neurocognitive disorders

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Susana T Valente

2015-10-01

Full Text Available Antiretroviral therapy (ART has dramatically improved the lives of HIV-1 infected individuals. Nonetheless, HIV associated neurocognitive disorders (HAND, which range from undetectable neurocognitive impairments to severe dementia, still affect approximately 50% of the infected population, hampering their quality of life.The persistence of HAND is promoted by several factors, including longer life expectancies, the residual levels of virus in the central nervous system and the continued presence of HIV-1 regulatory proteins such as the transactivator of transcription (Tat in the brain. Tat is a secreted viral protein that crosses the blood brain barrier into the central nervous system, where it has the ability to directly act on neurons and non-neuronal cells alike. These actions result in the release of soluble factors involved in inflammation, oxidative stress and excitotoxicity, ultimately resulting in neuronal damage. The percentage of methamphetamine abusers is high among the HIV-1-positive population compared to the general population. On the other hand, methamphetamine abuse is correlated with increased viral replication, enhanced Tat-mediated neurotoxicity and neurocognitive impairments. Although several strategies have been investigated to reduce HAND and methamphetamine use, no clinically approved treatment is currently available. Here, we review the latest findings of the effects of Tat and methamphetamine in HAND and discuss a few promising potential therapeutic developments.

Effects of altered TatC proteins on protein secretion efficiency via the twin-arginine translocation pathway of Bacillus subtilis

NARCIS (Netherlands)

Eijlander, Robyn T.; Kolbusz, Magdalena A.; Berendsen, Erwin M.; Kuipers, Oscar P.

Protein translocation via the Tat machinery in thylakoids and bacteria occurs through a cooperation between the TatA, TatB and TatC subunits, of which the TatC protein forms the initial Tat substrate-binding site. The Bacillus subtilis Tat machinery lacks TatB and comprises two separate TatAC

Overproduction of a Model Sec- and Tat-Dependent Secretory Protein Elicits Different Cellular Responses in Streptomyces lividans.

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Sonia Gullón

Full Text Available Streptomyces lividans is considered an efficient host for the secretory production of homologous and heterologous proteins. To identify possible bottlenecks in the protein production process, a comparative transcriptomic approach was adopted to study cellular responses during the overproduction of a Sec-dependent model protein (alpha-amylase and a Tat-dependent model protein (agarase in Streptomyces lividans. The overproduction of the model secretory proteins via the Sec or the Tat route in S. lividans does elicit a different major cell response in the bacterium. The stringent response is a bacterial response to nutrients' depletion, which naturally occurs at late times of the bacterial cell growth. While the induction of the stringent response at the exponential phase of growth may limit overall productivity in the case of the Tat route, the induction of that response does not take place in the case of the Sec route, which comparatively is an advantage in secretory protein production processes. Hence, this study identifies a potential major drawback in the secretory protein production process depending on the secretory route, and provides clues to improving S. lividans as a protein production host.

The HIV-1 transcriptional activator Tat has potent nucleic acid chaperoning activities in vitro.

Science.gov (United States)

Kuciak, Monika; Gabus, Caroline; Ivanyi-Nagy, Roland; Semrad, Katharina; Storchak, Roman; Chaloin, Olivier; Muller, Sylviane; Mély, Yves; Darlix, Jean-Luc

2008-06-01

The human immunodeficiency virus type 1 (HIV-1) is a primate lentivirus that causes the acquired immunodeficiency syndrome (AIDS). In addition to the virion structural proteins and enzyme precursors, that are Gag, Env and Pol, HIV-1 encodes several regulatory proteins, notably a small nuclear transcriptional activator named Tat. The Tat protein is absolutely required for virus replication since it controls proviral DNA transcription to generate the full-length viral mRNA. Tat can also regulate mRNA capping and splicing and was recently found to interfere with the cellular mi- and siRNA machinery. Because of its extensive interplay with nucleic acids, and its basic and disordered nature we speculated that Tat had nucleic acid-chaperoning properties. This prompted us to examine in vitro the nucleic acid-chaperoning activities of Tat and Tat peptides made by chemical synthesis. Here we report that Tat has potent nucleic acid-chaperoning activities according to the standard DNA annealing, DNA and RNA strand exchange, RNA ribozyme cleavage and trans-splicing assays. The active Tat(44-61) peptide identified here corresponds to the smallest known sequence with DNA/RNA chaperoning properties.

海马神经元中TAT-GluR6-9c-dansyl小肽的荧光观察%Delivery of GluR6-9c into hippocampal neurons by TAT transduction domain

Institute of Scientific and Technical Information of China (English)

纵艳艳; 裴冬生; 孙亚峰; 张光毅

2005-01-01

目的研究TAT-GluR6-9c-dansyl荧光小肽是否可以进入细胞内部.方法在培养的海马神经元中加入TAT-GluR6-9c-dansyl荧光小肽和对照肽TAT38-48-dansyl.结果用10 μmol/L TAT-GluR6-9c-dansyl处理的海马神经元在荧光显微镜下可以观到绿色荧光的出现,而对照肽TAT38-48-dansyl无荧光出现.结论 TAT-GluR6-9c-dansyl荧光小肽可以进入细胞.

DmsD, a Tat system specific chaperone, interacts with other general chaperones and proteins involved in the molybdenum cofactor biosynthesis

OpenAIRE

Li, Haiming; Chang, Limei; Howell, Jenika M.; Turner, Raymond J.

2010-01-01

Many bacterial oxidoreductases depend on the Tat translocase for correct cell localization. Substrates for the Tat translocase possess twin-arginine leaders. System specific chaperones or redox enzyme maturation proteins (REMPs) are a group of proteins implicated in oxidoreductase maturation. DmsD is a REMP discovered in Escherichia coli, which interacts with the twin-arginine leader sequence of DmsA, the catalytic subunit of DMSO reductase. In this study, we identified several potential inte...

HIV-1 infection induces changes in expression of cellular splicing factors that regulate alternative viral splicing and virus production in macrophages

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Purcell Damian FJ

2008-02-01

Full Text Available Abstract Background Macrophages are important targets and long-lived reservoirs of HIV-1, which are not cleared of infection by currently available treatments. In the primary monocyte-derived macrophage model of infection, replication is initially productive followed by a decline in virion output over ensuing weeks, coincident with a decrease in the levels of the essential viral transactivator protein Tat. We investigated two possible mechanisms in macrophages for regulation of viral replication, which appears to be primarily regulated at the level of tat mRNA: 1 differential mRNA stability, used by cells and some viruses for the rapid regulation of gene expression and 2 control of HIV-1 alternative splicing, which is essential for optimal viral replication. Results Following termination of transcription at increasing times after infection in macrophages, we found that tat mRNA did indeed decay more rapidly than rev or nef mRNA, but with similar kinetics throughout infection. In addition, tat mRNA decayed at least as rapidly in peripheral blood lymphocytes. Expression of cellular splicing factors in uninfected and infected macrophage cultures from the same donor showed an inverse pattern over time between enhancing factors (members of the SR family of RNA binding proteins and inhibitory factors (members of the hnRNP family. While levels of the SR protein SC35 were greatly up-regulated in the first week or two after infection, hnRNPs of the A/B and H groups were down-regulated. Around the peak of virus production in each culture, SC35 expression declined to levels in uninfected cells or lower, while the hnRNPs increased to control levels or above. We also found evidence for increased cytoplasmic expression of SC35 following long-term infection. Conclusion While no evidence of differential regulation of tat mRNA decay was found in macrophages following HIV-1 infection, changes in the balance of cellular splicing factors which regulate alternative

RECOVERY ACT - Thylakoid Assembly and Folded Protein Transport by the Tat Pathway

Energy Technology Data Exchange (ETDEWEB)

Dabney-Smith, Carole [Miami Univ., Oxford, OH (United States)

2016-07-18

Assembly of functional photosystems complete with necessary intrinsic (membrane-bound) and extrinsic proteins requires the function of at least 3 protein transport pathways in thylakoid membranes. Our research focuses on one of those pathways, a unique and essential protein transport pathway found in the chloroplasts of plants, bacteria, and some archaebacteria, the Twin arginine translocation (Tat) system. The chloroplast Tat (cpTat) system is thought to be responsible for the proper location of ~50% of thylakoid lumen proteins, several of which are necessary for proper photosystem assembly, maintenance, and function. Specifically, cpTat systems are unique because they transport fully folded and assembled proteins across ion tight membranes using only three membrane components, Tha4, Hcf106, and cpTatC, and the protonmotive force generated by photosynthesis. Despite the importance of the cpTat system in plants, the mechanism of transport of a folded precursor is not well known. Our long-term goal is to investigate the role protein transport systems have on organelle biogenesis, particularly the assembly of membrane protein complexes in thylakoids of chloroplasts. The objective of this proposal is to correlate structural changes in the membrane-bound cpTat component, Tha4, to the mechanism of translocation of folded-precursor substrates across the membrane bilayer by using a cysteine accessibility and crosslinking approach. Our central hypothesis is that the precursor passes through a proteinaceous pore of assembled Tha4 protomers that have undergone a conformational or topological change in response to transport. This research is predicated upon the observations that Tha4 exists in molar excess in the membrane relative to the other cpTat components; its regulated assembly to the precursor-bound receptor; and our data showing oligomerization of Tha4 into very large complexes in response to transport. Our rationale for these studies is that understanding cpTat

Controlling cellular P-TEFb activity by the HIV-1 transcriptional transactivator Tat.

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Lisa Muniz

Full Text Available The human immunodeficiency virus 1 (HIV-1 transcriptional transactivator (Tat is essential for synthesis of full-length transcripts from the integrated viral genome by RNA polymerase II (Pol II. Tat recruits the host positive transcription elongation factor b (P-TEFb to the HIV-1 promoter through binding to the transactivator RNA (TAR at the 5'-end of the nascent HIV transcript. P-TEFb is a general Pol II transcription factor; its cellular activity is controlled by the 7SK small nuclear RNA (snRNA and the HEXIM1 protein, which sequester P-TEFb into transcriptionally inactive 7SK/HEXIM/P-TEFb snRNP. Besides targeting P-TEFb to HIV transcription, Tat also increases the nuclear level of active P-TEFb through promoting its dissociation from the 7SK/HEXIM/P-TEFb RNP by an unclear mechanism. In this study, by using in vitro and in vivo RNA-protein binding assays, we demonstrate that HIV-1 Tat binds with high specificity and efficiency to an evolutionarily highly conserved stem-bulge-stem motif of the 5'-hairpin of human 7SK snRNA. The newly discovered Tat-binding motif of 7SK is structurally and functionally indistinguishable from the extensively characterized Tat-binding site of HIV TAR and importantly, it is imbedded in the HEXIM-binding elements of 7SK snRNA. We show that Tat efficiently replaces HEXIM1 on the 7SK snRNA in vivo and therefore, it promotes the disassembly of the 7SK/HEXIM/P-TEFb negative transcriptional regulatory snRNP to augment the nuclear level of active P-TEFb. This is the first demonstration that HIV-1 specifically targets an important cellular regulatory RNA, most probably to promote viral transcription and replication. Demonstration that the human 7SK snRNA carries a TAR RNA-like Tat-binding element that is essential for the normal transcriptional regulatory function of 7SK questions the viability of HIV therapeutic approaches based on small drugs blocking the Tat-binding site of HIV TAR.

Topical ocular delivery to laser-induced choroidal neovascularization by dual internalizing RGD and TAT peptide-modified nanoparticles

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Chu YC

2017-02-01

 > primary NPs. iRGD and TAT dual-modified NPs thus displayed significant targeting and penetration ability both in vitro and in vivo, indicating that it is a promising drug delivery system for managing CNV via topical ocular administration. Keywords: nanoparticles, ocular drug delivery, choroidal neovascularization, RGD, cell-penetrating peptides

Relaxed evolution in the tyrosine aminotransferase gene tat in old world fruit bats (Chiroptera: Pteropodidae).

Science.gov (United States)

Shen, Bin; Fang, Tao; Yang, Tianxiao; Jones, Gareth; Irwin, David M; Zhang, Shuyi

2014-01-01

Frugivorous and nectarivorous bats fuel their metabolism mostly by using carbohydrates and allocate the restricted amounts of ingested proteins mainly for anabolic protein syntheses rather than for catabolic energy production. Thus, it is possible that genes involved in protein (amino acid) catabolism may have undergone relaxed evolution in these fruit- and nectar-eating bats. The tyrosine aminotransferase (TAT, encoded by the Tat gene) is the rate-limiting enzyme in the tyrosine catabolic pathway. To test whether the Tat gene has undergone relaxed evolution in the fruit- and nectar-eating bats, we obtained the Tat coding region from 20 bat species including four Old World fruit bats (Pteropodidae) and two New World fruit bats (Phyllostomidae). Phylogenetic reconstructions revealed a gene tree in which all echolocating bats (including the New World fruit bats) formed a monophyletic group. The phylogenetic conflict appears to stem from accelerated TAT protein sequence evolution in the Old World fruit bats. Our molecular evolutionary analyses confirmed a change in the selection pressure acting on Tat, which was likely caused by a relaxation of the evolutionary constraints on the Tat gene in the Old World fruit bats. Hepatic TAT activity assays showed that TAT activities in species of the Old World fruit bats are significantly lower than those of insectivorous bats and omnivorous mice, which was not caused by a change in TAT protein levels in the liver. Our study provides unambiguous evidence that the Tat gene has undergone relaxed evolution in the Old World fruit bats in response to changes in their metabolism due to the evolution of their special diet.

Relaxed evolution in the tyrosine aminotransferase gene tat in old world fruit bats (Chiroptera: Pteropodidae.

Directory of Open Access Journals (Sweden)

Bin Shen

Full Text Available Frugivorous and nectarivorous bats fuel their metabolism mostly by using carbohydrates and allocate the restricted amounts of ingested proteins mainly for anabolic protein syntheses rather than for catabolic energy production. Thus, it is possible that genes involved in protein (amino acid catabolism may have undergone relaxed evolution in these fruit- and nectar-eating bats. The tyrosine aminotransferase (TAT, encoded by the Tat gene is the rate-limiting enzyme in the tyrosine catabolic pathway. To test whether the Tat gene has undergone relaxed evolution in the fruit- and nectar-eating bats, we obtained the Tat coding region from 20 bat species including four Old World fruit bats (Pteropodidae and two New World fruit bats (Phyllostomidae. Phylogenetic reconstructions revealed a gene tree in which all echolocating bats (including the New World fruit bats formed a monophyletic group. The phylogenetic conflict appears to stem from accelerated TAT protein sequence evolution in the Old World fruit bats. Our molecular evolutionary analyses confirmed a change in the selection pressure acting on Tat, which was likely caused by a relaxation of the evolutionary constraints on the Tat gene in the Old World fruit bats. Hepatic TAT activity assays showed that TAT activities in species of the Old World fruit bats are significantly lower than those of insectivorous bats and omnivorous mice, which was not caused by a change in TAT protein levels in the liver. Our study provides unambiguous evidence that the Tat gene has undergone relaxed evolution in the Old World fruit bats in response to changes in their metabolism due to the evolution of their special diet.

Construction of a novel chimera consisting of a chelator-containing Tat peptide conjugated to a morpholino antisense oligomer for technetium-99m labeling and accelerating cellular kinetics

Energy Technology Data Exchange (ETDEWEB)

Zhang Yumin [Division of Nuclear Medicine, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655 (United States)]. E-mail: yumin.zhang@mpi.com; Tung, C.-H. [Center for Molecular Imaging Research, Massachusetts General Hospital/Harvard Medical School, Charlestown, MA 02129 (United States); He Jiang [Division of Nuclear Medicine, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655 (United States); Liu Ning [Division of Nuclear Medicine, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655 (United States); Yanachkov, Ivan [GlSynthesis, Worcester, MA 01605 (United States); Liu Guozheng [Division of Nuclear Medicine, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655 (United States); Rusckowski, Mary [Division of Nuclear Medicine, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655 (United States); Vanderheyden, Jean-Luc [Division of Nuclear Medicine, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655 (United States)

2006-02-15

The attempt to target the limited copies of messenger RNA (mRNA) in vivo with radiolabeled nucleobase oligomers as antisense probes is challenging. Selecting an antisense molecule with superior properties, enhancing the cellular kinetics, and improving the radiolabeling chemistry would be the reasonable approach to accomplish this goal. The present study reports a method to construct a chimera of phosphorodiamidate morpholino nucleobase oligomer (MORF) covalently conjugated to a peptide containing a cell membrane transduction Tat peptide and an N{sub 2}S{sub 2} chelator for technetium-99m ({sup 99m}Tc) radiolabeling (N{sub 2}S{sub 2}-Tat-MORF). The radiolabeling properties and cellular kinetics of {sup 99m}Tc-N{sub 2}S{sub 2}-Tat-MORF were measured. As hypothesized, the preparation of {sup 99m}Tc-N{sub 2}S{sub 2}-Tat-MORF could be achieved by an instant one-step method with labeling efficiency greater than 95%, and the {sup 99m}Tc-N{sub 2}S{sub 2}-Tat-MORF showed distinct properties in cell culture from those of a control, the same MORF sequence without Tat but with mercaptoacetyltriglycine (MAG{sub 3}) as chelator for {sup 99m}Tc ({sup 99m}Tc-MAG{sub 3}-MORF). {sup 99m}Tc-N{sub 2}S{sub 2}-Tat-MORF achieved maximum accumulation of about 35% within 2 h, while {sup 99m}Tc-MAG{sub 3}-MORF showed lower and steadily increasing accumulations but of less than 1% in 24 h. These preliminary results demonstrated that the proposed chimera has properties for easy labeling, and {sup 99m}Tc-N{sub 2}S{sub 2}-Tat-MORF prepared by this method possesses enhanced cellular kinetics and merits further investigation for in vivo mRNA targeting.

Deciphering structure-activity relationships in a series of Tat/TAR inhibitors.

Science.gov (United States)

Pascale, Lise; González, Alejandro López; Di Giorgio, Audrey; Gaysinski, Marc; Teixido Closa, Jordi; Tejedor, Roger Estrada; Azoulay, Stéphane; Patino, Nadia

2016-11-01

A series of pentameric "Polyamide Amino Acids" (PAAs) compounds derived from the same trimeric precursor have been synthesized and investigated as HIV TAR RNA ligands, in the absence and in the presence of a Tat fragment. All PAAs bind TAR with similar sub-micromolar affinities but their ability to compete efficiently with the Tat fragment strongly differs, IC50 ranging from 35 nM to >2 μM. While NMR and CD studies reveal that all PAA interact with TAR at the same site and induce globally the same RNA conformational change upon binding, a comparative thermodynamic study of PAA/TAR equilibria highlights distinct TAR binding modes for Tat competitor and non-competitor PAAs. This led us to suggest two distinct interaction modes that have been further validated by molecular modeling studies. While the binding of Tat competitor PAAs induces a contraction at the TAR bulge region, the binding of non-competitor ones widens it. This could account for the distinct PAA ability to compete with Tat fragment. Our work illustrates how comparative thermodynamic studies of a series of RNA ligands of same chemical family are of value for understanding their binding modes and for rationalizing structure-activity relationships.

Trade-Space Analysis Tool for Constellations (TAT-C)

Science.gov (United States)

Le Moigne, Jacqueline; Dabney, Philip; de Weck, Olivier; Foreman, Veronica; Grogan, Paul; Holland, Matthew; Hughes, Steven; Nag, Sreeja

2016-01-01

Traditionally, space missions have relied on relatively large and monolithic satellites, but in the past few years, under a changing technological and economic environment, including instrument and spacecraft miniaturization, scalable launchers, secondary launches as well as hosted payloads, there is growing interest in implementing future NASA missions as Distributed Spacecraft Missions (DSM). The objective of our project is to provide a framework that facilitates DSM Pre-Phase A investigations and optimizes DSM designs with respect to a-priori Science goals. In this first version of our Trade-space Analysis Tool for Constellations (TAT-C), we are investigating questions such as: How many spacecraft should be included in the constellation? Which design has the best costrisk value? The main goals of TAT-C are to: Handle multiple spacecraft sharing a mission objective, from SmallSats up through flagships, Explore the variables trade space for pre-defined science, cost and risk goals, and pre-defined metrics Optimize cost and performance across multiple instruments and platforms vs. one at a time.This paper describes the overall architecture of TAT-C including: a User Interface (UI) interacting with multiple users - scientists, missions designers or program managers; an Executive Driver gathering requirements from UI, then formulating Trade-space Search Requests for the Trade-space Search Iterator first with inputs from the Knowledge Base, then, in collaboration with the Orbit Coverage, Reduction Metrics, and Cost Risk modules, generating multiple potential architectures and their associated characteristics. TAT-C leverages the use of the Goddard Mission Analysis Tool (GMAT) to compute coverage and ancillary data, streamlining the computations by modeling orbits in a way that balances accuracy and performance.TAT-C current version includes uniform Walker constellations as well as Ad-Hoc constellations, and its cost model represents an aggregate model consisting of

Intelligent tit-for-tat in the iterated prisoner's dilemma game

Science.gov (United States)

Baek, Seung Ki; Kim, Beom Jun

2008-07-01

We seek a route to the equilibrium where all the agents cooperate in the iterated prisoner’s dilemma game on a two-dimensional plane, focusing on the role of tit-for-tat strategy. When a time horizon, within which a strategy can recall the past, is one time step, an equilibrium can be achieved as cooperating strategies dominate the whole population via proliferation of tit-for-tat. Extending the time horizon, we filter out poor strategies by simplified replicator dynamics and observe a similar evolutionary pattern to reach the cooperating equilibrium. In particular, the rise of a modified tit-for-tat strategy plays a central role, which implies how a robust strategy is adopted when provided with an enhanced memory capacity.

Engineering of a novel tri-functional enzyme with MnSOD, catalase and cell-permeable activities.

Science.gov (United States)

Luangwattananun, Piriya; Yainoy, Sakda; Eiamphungporn, Warawan; Songtawee, Napat; Bülow, Leif; Ayudhya, Chartchalerm Isarankura Na; Prachayasittikul, Virapong

2016-04-01

Cooperative function of superoxide dismutase (SOD) and catalase (CAT), in protection against oxidative stress, is known to be more effective than the action of either single enzyme. Chemical conjugation of the two enzymes resulted in molecules with higher antioxidant activity and therapeutic efficacy. However, chemical methods holds several drawbacks; e.g., loss of enzymatic activity, low homogeneity, time-consuming, and the need of chemical residues removal. Yet, the conjugated enzymes have never been proven to internalize into target cells. In this study, by employing genetic and protein engineering technologies, we reported designing and production of a bi-functional protein with SOD and CAT activities for the first time. To enable cellular internalization, cell penetrating peptide from HIV-1 Tat (TAT) was incorporated. Co-expression of CAT-MnSOD and MnSOD-TAT fusion genes allowed simultaneous self-assembly of the protein sequences into a large protein complex, which is expected to contained one tetrameric structure of CAT, four tetrameric structures of MnSOD and twelve units of TAT. The protein showed cellular internalization and superior protection against paraquat-induced cell death as compared to either complex bi-functional protein without TAT or to native enzymes fused with TAT. This study not only provided an alternative strategy to produce multifunctional protein complex, but also gained an insight into the development of therapeutic agent against oxidative stress-related conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

HIV-1 Tat and AIDS-associated cancer: targeting the cellular anti-cancer barrier?

Directory of Open Access Journals (Sweden)

Daniel René

2008-05-01

Full Text Available Abstract The acquired immunodeficiency syndrome (AIDS is accompanied by a significant increase in the incidence of neoplasms. Several causative agents have been proposed for this phenomenon. These include immunodeficiency and oncogenic DNA viruses and the HIV-1 protein Tat. Cancer in general is closely linked to genomic instability and DNA repair mechanisms. The latter maintains genomic stability and serves as a cellular anti-cancer barrier. Defects in DNA repair pathway are associated with carcinogenesis. This review focuses on newly discovered connections of the HIV-1 protein Tat, as well as cellular co-factors of Tat, to double-strand break DNA repair. We propose that the Tat-induced DNA repair deficiencies may play a significant role in the development of AIDS-associated cancer.

Enquête internationale sur l'état de l'art et l'état de la pratique en géotechnique

Science.gov (United States)

Acosta-Martinez, Hugo; Delage, Pierre; Nicks, Jennifer; Day, Peter

2018-05-01

Cet article présente une synthèse des résultats de l'enquête internationale sur l'état de l'art et l'état de la pratique en ingénierie géotechnique lancée par le Groupe présidentiel des entreprises associées et le Comité de supervision technique de la Société internationale de mécanique des sols et de géotechnique en mars 2017. Il résume également les discussions qui ont eu lieu sur le sujet durant le 19e CIMSG à Séoul, le 20 septembre 2017.

Efficient Production of an Engineered Apoptin from Chicken Anemia Virus in a Recombinant E. coli for Tumor Therapeutic Applications

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Lee Meng-Shiou

2012-06-01

Full Text Available Abstract Background Apoptin, a nonstructural protein encoded by the VP3 gene of chicken anemia virus (CAV, has been shown to not only induce apoptosis when introduced into the precursors of chicken thymocytes, but has been found to specifically kill human cancer cells, tumor cell and transformed cells without affecting the proliferation of normal cells. This tumor-specific apoptotic characteristic of the protein potentially may allow the development of a protein drug that has applications in tumor therapy. However, several major problems, which include poor expression and poor protein solubility, have hampered the production of apoptin in bacteria. Results Significantly increased expression of recombinant full-length apoptin that originated from chicken anemia virus was demonstrated using an E. coli expression system. The CAV VP3 gene was fused with a synthetic sequence containing a trans-acting activator of transcription (TAT protein transduction domain (PTD. The resulting construct was cloned into various different expression vectors and these were then expressed in various E. coli strains. The expression of the TAT-Apoptin in E. coli was significantly increased when TAT-Apoptin was fused with GST-tag rather than a His-tag. When the various rare amino acid codons of apoptin were optimized, the expression level of the GST-TAT-Apoptinopt in E. coli BL21(DE3 was significantly further increased. The highest protein expression level obtained was 8.33 g/L per liter of bacterial culture after induction with 0.1 mM IPTG for 4 h at 25 °C. Moreover, approximately 90% of the expressed GST-TAT-Apoptinopt under these conditions was soluble. After purification by GST affinity chromatography, the purified recombinant TAT-Apoptinopt protein was used to evaluate the recombinant protein’s apoptotic activity on tumor cells. The results demonstrated that the E. coli-expressed GST-TAT-apoptinopt showed apoptotic activity and was able to induce human

Caprine arthritis encephalitis virus dysregulates the expression of cytokines in macrophages.

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Lechner, F; Machado, J; Bertoni, G; Seow, H F; Dobbelaere, D A; Peterhans, E

1997-01-01

Caprine arthritis encephalitis virus (CAEV) is a lentivirus of goats that leads to chronic mononuclear infiltration of various tissues, in particular, the radiocarpal joints. Cells of the monocyte/macrophage lineage are the major host cells of CAEV in vivo. We have shown that infection of cultured goat macrophages with CAEV results in an alteration of cytokine expression in vitro. Constitutive expression of interleukin 8 (IL-8) and monocyte chemoattractant protein 1 (MCP-1) was increased in infected macrophages, whereas transforming growth factor beta1 (TGF-beta1) mRNA was down-regulated. When macrophages were infected with a CAEV clone lacking the trans-acting nuclear regulatory gene tat, IL-8 and MCP-1 were also increased. No significant differences from cells infected with the wild-type clone were observed, suggesting that Tat is not required for the increased expression of IL-8 and MCP-1 in infected macrophages. Furthermore, infection with CAEV led to an altered pattern of cytokine expression in response to lipopolysaccharide (LPS), heat-killed Listeria monocytogenes plus gamma interferon, or fixed cells of Staphylococcus aureus Cowan I. In infected macrophages, tumor necrosis factor alpha, IL-1beta, IL-6, and IL-12 p40 mRNA expression was reduced in response to all stimuli tested whereas changes in expression of granulocyte-macrophage colony-stimulating factor depended on the stimulating agent. Electrophoretic mobility shift assays demonstrated that, in contrast to effects of human immunodeficiency virus infection of macrophages, CAEV infection had no effect on the level of constitutive nuclear factor-kappaB (NF-kappaB) activity or on the level of LPS-stimulated NF-kappaB activity, suggesting that NF-kappaB is not involved in altered regulation of cytokine expression in CAEV-infected cells. In contrast, activator protein 1 (AP-1) binding activity was decreased in infected macrophages. These data show that CAEV infection may result in a dysregulation of

États financiers 2015–2016

International Development Research Centre (IDRC) Digital Library (Canada)

une assurance raisonnable qu'il pourra réaliser ses objectifs. .... les employés et leur procure des services de santé avant ...... indépendance, à un audit des états financiers annuels, conformément aux normes d'audit généralement reconnues.

L'état de plasma le feu de l'Univers

CERN Document Server

Lehner, Thierry

2004-01-01

Dans l'Antiquité, les Grecs considéraient que les constituants du monde dérivaient de quatre éléments essentiels : la terre, l'eau, l'air et le feu. Il n'est pas difficile de voir dans les trois premiers l'équivalent de nos états solide, liquide et gazeux. Mais l'état physique le plus répandu dans l'Univers - correspondant au feu des Anciens - n'est apparu que récemment et n'a été reconnu par la communauté des physiciens qu'en 1928 : c'est le plasma. Cet état très étrange - gazeux, électrique, lumineux, impalpable - reste le plus exotique et le plus inattendu. Il a donné naissance aux trois autres états puisque, à l'exception des éléments ultra-légers que sont l'hydrogène et l'hélium, tous ceux qui constituent notre monde (carbone, oxygène, fer, etc.) sont apparus dans ces fourneaux gigantesques, ces monstres de plasma, qu'étaient les premières étoiles. La vie elle-même en découle par ricochet, ce qui a permis de dire que nous ne sommes que des " poussières d'étoiles ". Décou...

Application of Bacillus sp. TAT105 to reduce ammonia emissions during pilot-scale composting of swine manure.

Science.gov (United States)

Kuroda, Kazutaka; Tanaka, Akihiro; Furuhashi, Kenich; Nakasaki, Kiyohiko

2017-12-01

Thermophilic ammonium-tolerant bacterium Bacillus sp. TAT105 grows and reduces ammonia (NH 3 ) emissions by assimilating ammonium nitrogen during composting of swine feces. To evaluate the efficacy of a biological additive containing TAT105 at reducing NH 3 emissions, composting tests of swine manure on a pilot scale (1.8 m 3 ) were conducted. In the TAT105-added treatment, NH 3 emissions and nitrogen loss were lower than those in the control treatment without TAT105. No significant difference was detected in losses in the weight and volatile solids between the treatments. Concentration of thermophilic ammonium-tolerant bacteria in the compost increased in both treatments at the initial stage of composting. In the TAT105-added treatment, bacterial concentration reached ~10 9 colony-forming units per gram of dry matter, several-fold higher than that in the control and stayed at the same level until the end. These results suggest that TAT105 grows during composting and reduces NH 3 emissions in TAT105-added treatment.

TIT FOR TAT in sticklebacks and the evolution of cooperation

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Milinski, Manfred

1987-01-01

The problems of achieving mutual cooperation can be formalized in a game called the Prisoner's Dilemma in which selfish defection is always more rewarding than cooperation1. If the two protagonists have a certain minimum probability of meeting again a strategy called TIT FOR TAT is very successful2. In TIT FOR TAT the player cooperates on the first move and thereafter does whatever the opponent did on the previous move. I have studied the behaviour of fish when confronting a potential predator, because conflicts can arise within pairs of fish in these circumstances which I argue resemble a series of games of Prisoner's Dilemma. Using a system of mirrors, single three-spined sticklebacks (Gasterosteus aculeatus) approaching a live predator were provided with either a simulated cooperating companion or a simulated defecting one. In both cases the test fish behaved according to TIT FOR TAT supporting the hypothesis that cooperation can evolve among egoists.

HIV-1 transgene expression in rats causes oxidant stress and alveolar epithelial barrier dysfunction

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Jacob Barbara A

2009-02-01

Full Text Available Abstract Background HIV-infected individuals are at increased risk for acute and chronic airway disease even though there is no evidence that the virus can infect the lung epithelium. Although HIV-related proteins including gp120 and Tat can directly cause oxidant stress and cellular dysfunction, their effects in the lung are unknown. The goal of this study was to determine the effects of HIV-1 transgene expression in rats on alveolar epithelial barrier function. Alveolar epithelial barrier function was assessed by determining lung liquid clearance in vivo and alveolar epithelial monolayer permeability in vitro. Oxidant stress in the alveolar space was determined by measuring the glutathione redox couple by high performance liquid chromatography, and the expression and membrane localization of key tight junction proteins were assessed. Finally, the direct effects of the HIV-related proteins gp120 and Tat on alveolar epithelial barrier formation and tight junction protein expression were determined. Results HIV-1 transgene expression caused oxidant stress within the alveolar space and impaired epithelial barrier function even though there was no evidence of overt inflammation within the airways. The expression and membrane localization of the tight junction proteins zonula occludens-1 and occludin were decreased in alveolar epithelial cells from HIV-1 transgenic rats. Further, treating alveolar epithelial monolayers from wild type rats in vitro with recombinant gp120 or Tat for 24 hours reproduced many of the effects on zonula occludens-1 and occludin expression and membrane localization. Conclusion Taken together, these data indicate that HIV-related proteins cause oxidant stress and alter the expression of critical tight junction proteins in the alveolar epithelium, resulting in barrier dysfunction.

Direct effects of HIV-1 Tat on excitability and survival of primary dorsal root ganglion neurons: possible contribution to HIV-1-associated pain.

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Xianxun Chi

Full Text Available The vast majority of people living with human immunodeficiency virus type 1 (HIV-1 have pain syndrome, which has a significant impact on their quality of life. The underlying causes of HIV-1-associated pain are not likely attributable to direct viral infection of the nervous system due to the lack of evidence of neuronal infection by HIV-1. However, HIV-1 proteins are possibly involved as they have been implicated in neuronal damage and death. The current study assesses the direct effects of HIV-1 Tat, one of potent neurotoxic viral proteins released from HIV-1-infected cells, on the excitability and survival of rat primary dorsal root ganglion (DRG neurons. We demonstrated that HIV-1 Tat triggered rapid and sustained enhancement of the excitability of small-diameter rat primary DRG neurons, which was accompanied by marked reductions in the rheobase and resting membrane potential (RMP, and an increase in the resistance at threshold (R(Th. Such Tat-induced DRG hyperexcitability may be a consequence of the inhibition of cyclin-dependent kinase 5 (Cdk5 activity. Tat rapidly inhibited Cdk5 kinase activity and mRNA production, and roscovitine, a well-known Cdk5 inhibitor, induced a very similar pattern of DRG hyperexcitability. Indeed, pre-application of Tat prevented roscovitine from having additional effects on the RMP and action potentials (APs of DRGs. However, Tat-mediated actions on the rheobase and R(Th were accelerated by roscovitine. These results suggest that Tat-mediated changes in DRG excitability are partly facilitated by Cdk5 inhibition. In addition, Cdk5 is most abundant in DRG neurons and participates in the regulation of pain signaling. We also demonstrated that HIV-1 Tat markedly induced apoptosis of primary DRG neurons after exposure for longer than 48 h. Together, this work indicates that HIV-1 proteins are capable of producing pain signaling through direct actions on excitability and survival of sensory neurons.

The HIV-1 viral protein Tat increases glutamate and decreases GABA exocytosis from human and mouse neocortical nerve endings.

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Musante, Veronica; Summa, Maria; Neri, Elisa; Puliti, Aldamaria; Godowicz, Tomasz T; Severi, Paolo; Battaglia, Giuseppe; Raiteri, Maurizio; Pittaluga, Anna

2010-08-01

Human immunodeficiency virus-1 (HIV-1)-encoded transactivator of transcription (Tat) potentiated the depolarization-evoked exocytosis of [(3)H]D-aspartate ([(3)H]D-ASP) from human neocortical terminals. The metabotropic glutamate (mGlu) 1 receptor antagonist 7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxylate ethyl ester (CPCCOEt) prevented this effect, whereas the mGlu5 receptor antagonist 2-methyl-6-(phenylethynyl) pyridine hydrochloride (MPEP) was ineffective. Western blot analysis showed that human neocortex synaptosomes possess mGlu1 and mGlu5 receptors. Tat potentiated the K(+)-evoked release of [(3)H]D-ASP or of endogenous glutamate from mouse neocortical synaptosomes in a CPCCOEt-sensitive and MPEP-insensitive manner. Deletion of mGlu1 receptors (crv4/crv4 mice) or mGlu5 receptors (mGlu5(-/-)mouse) silenced Tat effects. Tat enhanced inositol 1,4,5-trisphosphate production in human and mouse neocortical synaptosomes, consistent with the involvement of group I mGlu receptors. Tat inhibited the K(+)-evoked release of [(3)H]gamma-aminobutyric acid ([(3)H]GABA) from human synaptosomes and that of endogenous GABA or [(3)H]GABA from mouse nerve terminals; the inhibition was insensitive to CPCCOEt or MPEP. Tat-induced effects were retained by Tat(37-72) but not by Tat(48-85). In mouse neocortical slices, Tat facilitated the K(+)- and the veratridine-induced release of [(3)H]D-ASP in a CPCCOEt-sensitive manner and was ineffective in crv4/crv4 mouse slices. These observations are relevant to the comprehension of the pathophysiological effects of Tat in central nervous system and may suggest new potential therapeutic approaches to the cure of HIV-1-associated dementia.

Improving ED specimen TAT using Lean Six Sigma.

Science.gov (United States)

Sanders, Janet H; Karr, Tedd

2015-01-01

Lean and Six Sigma are continuous improvement methodologies that have garnered international fame for improving manufacturing and service processes. Increasingly these methodologies are demonstrating their power to also improve healthcare processes. The purpose of this paper is to discuss a case study for the application of Lean and Six Sigma tools in the reduction of turnaround time (TAT) for Emergency Department (ED) specimens. This application of the scientific methodologies uncovered opportunities to improve the entire ED to lab system for the specimens. This case study provides details on the completion of a Lean Six Sigma project in a 1,000 bed tertiary care teaching hospital. Six Sigma's Define, Measure, Analyze, Improve, and Control methodology is very similar to good medical practice: first, relevant information is obtained and assembled; second, a careful and thorough diagnosis is completed; third, a treatment is proposed and implemented; and fourth, checks are made to determine if the treatment was effective. Lean's primary goal is to do more with less work and waste. The Lean methodology was used to identify and eliminate waste through rapid implementation of change. The initial focus of this project was the reduction of turn-around-times for ED specimens. However, the results led to better processes for both the internal and external customers of this and other processes. The project results included: a 50 percent decrease in vials used for testing, a 50 percent decrease in unused or extra specimens, a 90 percent decrease in ED specimens without orders, a 30 percent decrease in complete blood count analysis (CBCA) Median TAT, a 50 percent decrease in CBCA TAT Variation, a 10 percent decrease in Troponin TAT Variation, a 18.2 percent decrease in URPN TAT Variation, and a 2-5 minute decrease in ED registered nurses rainbow draw time. This case study demonstrated how the quantitative power of Six Sigma and the speed of Lean worked in harmony to improve

Interference with RUNX1/ETO Leukemogenic Function by Cell-Penetrating Peptides Targeting the NHR2 Oligomerization Domain

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Yvonne Bartel

2013-01-01

Full Text Available The leukemia-associated fusion protein RUNX1/ETO is generated by the chromosomal translocation t(8;21 which appears in about 12% of all de novo acute myeloid leukemias (AMLs. Essential for the oncogenic potential of RUNX1/ETO is the oligomerization of the chimeric fusion protein through the nervy homology region 2 (NHR2 within ETO. In previous studies, we have shown that the intracellular expression of peptides containing the NHR2 domain inhibits RUNX1/ETO oligomerization, thereby preventing cell proliferation and inducing differentiation of RUNX1/ETO transformed cells. Here, we show that introduction of a recombinant TAT-NHR2 fusion polypeptide into the RUNX1/ETO growth-dependent myeloid cell line Kasumi-1 results in decreased cell proliferation and increased numbers of apoptotic cells. This effect was highly specific and mediated by binding the TAT-NHR2 peptide to ETO sequences, as TAT-polypeptides containing the oligomerization domain of BCR did not affect cell proliferation or apoptosis in Kasumi-1 cells. Thus, the selective interference with NHR2-mediated oligomerization by peptides represents a challenging but promising strategy for the inhibition of the leukemogenic potential of RUNX1/ETO in t(8;21-positive leukemia.

Tit-For-Tat Strategy for Increasing Medical Student Evaluation Response Rates

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Matthew G. Malone

2017-12-01

Full Text Available Introducation It is essential for faculty to receive feedback on their teaching for the purpose of improvement as well as promotion. It can be challenging to motivate students to provide feedback to preceptors and fill out evaluation forms when not a clerkship requirement. Furthermore, there is concern that making the evaluations a requirement can compromise the quality of the feedback. The objective of this study was to identify an increase in the number of faculty and resident evaluations completed by students rotating through their Emergency Medicine clerkship following the implementation of a tit-for-tat incentive strategy. Method Prior to the implementation of Tit-for-Tat, students rotating through their emergency medicine clerkship were asked to fill out evaluations of residents and faculty members with whom they worked. These were encouraged but voluntary. Beginning in the 2014–2015 academic year, a tit-for-tat strategy was employed whereby students had to complete a resident or faculty evaluation in order to view the student assessment completed by that resident or faculty preceptor. Results Students submitted 1101 evaluations in the control, with a mean of 3.60 evaluations completed per student and 3.77 evaluations received per preceptor. Following the implementation of tit-for-tat, students submitted 2736 evaluations, with a mean of 8.19 evaluations completed per student and 7.52 evaluations received per preceptor. Both the increase in evaluations completed per student and evaluations received per preceptor were statistically significant with p-value <0.001. Conclusion The tit-for-tat strategy significantly increased the number of evaluations submitted by students rotating through their emergency medicine clerkship. This has served as an effective tool to increase the overall number of evaluations completed, the number of evaluations each instructor received on average and the proportion of students that completed evaluations

A novel branched TAT(47-57) peptide for selective Ni(2+) introduction into the human fibrosarcoma cell nucleus.

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Szyrwiel, Łukasz; Shimura, Mari; Shirataki, Junko; Matsuyama, Satoshi; Matsunaga, Akihiro; Setner, Bartosz; Szczukowski, Łukasz; Szewczuk, Zbigniew; Yamauchi, Kazuto; Malinka, Wiesław; Chavatte, Laurent; Łobinski, Ryszard

2015-07-01

A TAT47-57 peptide was modified on the N-terminus by elongation with a 2,3-diaminopropionic acid residue and then by coupling of two histidine residues on its N-atoms. This branched peptide could bind to Ni under physiological conditions as a 1 : 1 complex. We demonstrated that the complex was quantitatively taken up by human fibrosarcoma cells, in contrast to Ni(2+) ions. Ni localization (especially at the nuclei) was confirmed by imaging using both scanning X-ray fluorescence microscopy and Newport Green fluorescence. A competitive assay with Newport Green showed that the latter displaced the peptide ligand from the Ni-complex. Ni(2+) delivered as a complex with the designed peptide induced substantially more DNA damage than when introduced as a free ion. The availability of such a construct opens up the way to investigate the importance of the nucleus as a target for the cytotoxicity, genotoxicity or carcinogenicity of Ni(2+).

A Yersinia pestis tat mutant is attenuated in bubonic and small-aerosol pneumonic challenge models of infection but not as attenuated by intranasal challenge.

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Joel Bozue

Full Text Available Bacterial proteins destined for the Tat pathway are folded before crossing the inner membrane and are typically identified by an N-terminal signal peptide containing a twin arginine motif. Translocation by the Tat pathway is dependent on the products of genes which encode proteins possessing the binding site of the signal peptide and mediating the actual translocation event. In the fully virulent CO92 strain of Yersinia pestis, the tatA gene was deleted. The mutant was assayed for loss of virulence through various in vitro and in vivo assays. Deletion of the tatA gene resulted in several consequences for the mutant as compared to wild-type. Cell morphology of the mutant bacteria was altered and demonstrated a more elongated form. In addition, while cultures of the mutant strain were able to produce a biofilm, we observed a loss of adhesion of the mutant biofilm structure compared to the biofilm produced by the wild-type strain. Immuno-electron microscopy revealed a partial disruption of the F1 antigen on the surface of the mutant. The virulence of the ΔtatA mutant was assessed in various murine models of plague. The mutant was severely attenuated in the bubonic model with full virulence restored by complementation with the native gene. After small-particle aerosol challenge in a pneumonic model of infection, the mutant was also shown to be attenuated. In contrast, when mice were challenged intranasally with the mutant, very little difference in the LD50 was observed between wild-type and mutant strains. However, an increased time-to-death and delay in bacterial dissemination was observed in mice infected with the ΔtatA mutant as compared to the parent strain. Collectively, these findings demonstrate an essential role for the Tat pathway in the virulence of Y. pestis in bubonic and small-aerosol pneumonic infection but less important role for intranasal challenge.

Evidence for conformational flexibility in the Tat-TAR recognition motif of cyclin T1

International Nuclear Information System (INIS)

Das, Chandreyee; Edgcomb, Stephen P.; Peteranderl, Ralph; Chen, Lily; Frankel, Alan D.

2004-01-01

Cyclin T1 (CycT1) is a cellular transcription elongation factor that also participates in Tat-mediated activation of several lentiviral promoters. In human immunodeficiency virus (HIV), CycT1 is required for Tat to bind tightly to TAR and interacts in the ternary complex via its Tat-TAR recognition motif (TRM). In the related bovine immunodeficiency virus (BIV), Tat recognizes its cognate TAR element with high affinity and specificity in the absence of CycT1. At both promoters, CycT1 recruits the Cdk9 kinase, which phosphorylates RNA polymerase II to generate processive transcription complexes. To examine the physical properties of CycT1, we purified a functional domain corresponding to residues 1-272 and found that it possesses a stably folded core, as judged by partial proteolysis and circular dichroism experiments. Interestingly, the C-terminal 20 residues corresponding to the TRM appear conformationally flexible or disordered. The TRM of the bovine CycT1 (bCycT1) is similarly sensitive to proteolysis yet differs in sequence from the human protein. In particular, bCycT1 lacks a cysteine at residue 261 known to be critical for HIV but not BIV ternary complex formation, and mutagenesis data are consistent with a proposed role for this cysteine in metal binding. The apparent flexibility of the TRM suggests that conformational rearrangements may accompany formation of CycT1-Tat-TAR ternary complexes and may contribute to different TAR recognition strategies in different lentiviruses

Empty Turnip yellow mosaic virus capsids as delivery vehicles to mammalian cells.

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Kim, Doyeong; Lee, Younghee; Dreher, Theo W; Cho, Tae-Ju

2018-05-03

Turnip yellow mosaic virus (TYMV) was able to enter animal cells when the spherical plant virus was conjugated with Tat, a cell penetrating peptide (CPP). Tat was chemically attached to the surface lysine residues of TYMV using hydrazone chemistry. Baby hamster kidney (BHK) cells were incubated with either unmodified or Tat-conjugated TYMV and examined by flow cytometry and confocal microscopic analyses. Tat conjugation was shown to be more efficient than Lipofectamine in allowing TYMV to enter the mammalian cells. Tat-assisted-transfection was also associated with less loss of cell viability than lipofection. Among the CPPs tested (Tat, R8, Pep-1 and Pen), it was observed that R8 and Pen were also effective while Pep-1 was not. We also examined if the internal space of TYMV can be used to load fluorescein dye as a model cargo. When TYMV is treated by freezing and thawing, the virus is known to convert into a structure with a 6-8 nm hole and release viral RNA. When the resultant pot-like particles were reacted with fluorescein-5-maleimide using interior sulfhydryl groups as conjugation sites, about 145 fluorescein molecules were added per particle. The fluorescein-loaded TYMV particles were conjugated with Tat and introduced into BHK cells, again with higher transfection efficiency compared to lipofection. Our studies demonstrate the potential of modified TYMV as an efficient system for therapeutic cargo delivery to mammalian cells. Copyright © 2018 Elsevier B.V. All rights reserved.

Ultrastructural characterization of mesenchymal stromal cells labeled with ultrasmall superparamagnetic iron-oxide nanoparticles for clinical tracking studies

DEFF Research Database (Denmark)

Hansen, Louise; Hansen, Alastair B; Mathiasen, Anders B

2014-01-01

INTRODUCTION: To evaluate survival and engraftment of mesenchymal stromal cells (MSCs) in vivo, it is necessary to track implanted cells non-invasively with a method, which does not influence cellular ultrastructure and functional characteristics. Iron-oxide particles have been applied for cell...... sequence of trans-activator of transcription (TAT) (IODEX-TAT) and evaluate the effect of labeling on ultrastructure, viability, phenotype and proliferative capacity of the cells. MATERIALS AND METHODS: MSCs were labeled with 5 and 10 μg IODEX-TAT/10(5) cells for 2, 6 and 21 hours. IODEX-TAT uptake...... and cellular ultrastructure were determined by electron microscopy. Cell viability was determined by propidium iodide staining and cell proliferation capacity by 5-bromo-2-deoxyuridine (BrdU) incorporation. Maintenance of stem cell surface markers was determined by flow cytometry. Results. IODEX-TAT labeling...

TERBİNAFİNE KULLANIMINA BAĞLI TAT DUYUSU BOZUKLUĞU: BİR OLGU SUNUMU

OpenAIRE

Bayar, Özlem Filiz; Şenol Güven, Gamze; Ak, Gülsüm

2015-01-01

Amaç: Terbinafine Alilamin grubunda yer alan bir antifungal ajandır. 1991 yılında üretilmiş olup, topikal ve sistemik olarak geniş bir kullanıma sahiptir. Oral formunun kullanımıyla % 0.6 ile 2.8 oranlarında nadir görülen bir yan etki olan tat duyusu bozukluğu meydana gelmektedir. Bu olgu sunumunda, nadir görülen oral Terbinafine kullanımına bağlı tat duyusu bozukluğu gelişen bir hastayı sunmaktayız.Gereç ve yöntem: 43 yaşında erkek hasta oral Terbinafine kullanımı sonucu gelişen tat duyusu b...

Gene expression profiling in woman with women with breast cancer in a Saudi population

International Nuclear Information System (INIS)

Amer, Saud M. Bin; Maqbool, Z.; Nirmal, Maimoona S.; Hussain, Syed S.; Jeprel, Hatim A.; Qattan, Amal T.; Tulbah, Asma M.; Malik, Osama A.; Al-Tweigeri, Taher A.

2008-01-01

Objective was to generate consensus gene expression profiles of invasive breast tumors from a small cohort of Saudi females and to explore the possibility that they may be broadly conserved between Caucasian and Middle Eastern populations. This study was performed at King Faisal Specialist Hospital and Research Center, Riyadh, Kingdom of Saudi Arabia, from January 2005 to January 2007. Gene expression profiles were generated from 38 invasive breast tumors and 8 tumor adjacent tissues (TATs) using BD Atlas cDNA expression arrays containing 1176 genes. Results were confirmed by reverse transcriptase polymerase chain reaction and analyzed by 2-dimensional unsupervised hierarchical clustering. The analysis identified 48 differentially expressed genes in tumors from which 25 are already reported by various western studies. Forty-three of these genes were also differentially expressed in TATs. The same data set has been able to distinguish between tumors and the TAT's, interestingly by using only 4 of the differentially expressed genes. Moreover, we were able to group the patients according to prognosis to an extent by hierarchical clustering. Our results indicate that expression profiles between Saudi females with breast cancer and the Caucasian population are conserved to some extent, and can be used to classify patients according to prognostic groups. We also suggest 3 differentially expressed genes (IGHG3, CDK3 and RPS9) in tumors may have a novel role in breast cancer. In addition, the role of TATs is much more essential in breast cancer and needs to be explored thoroughly. (author)

Anti-apoptotic peptides protect against radiation-induced cell death

International Nuclear Information System (INIS)

McConnell, Kevin W.; Muenzer, Jared T.; Chang, Kathy C.; Davis, Chris G.; McDunn, Jonathan E.; Coopersmith, Craig M.; Hilliard, Carolyn A.; Hotchkiss, Richard S.; Grigsby, Perry W.; Hunt, Clayton R.

2007-01-01

The risk of terrorist attacks utilizing either nuclear or radiological weapons has raised concerns about the current lack of effective radioprotectants. Here it is demonstrated that the BH4 peptide domain of the anti-apoptotic protein Bcl-xL can be delivered to cells by covalent attachment to the TAT peptide transduction domain (TAT-BH4) and provide protection in vitro and in vivo from radiation-induced apoptotic cell death. Isolated human lymphocytes treated with TAT-BH4 were protected against apoptosis following exposure to 15 Gy radiation. In mice exposed to 5 Gy radiation, TAT-BH4 treatment protected splenocytes and thymocytes from radiation-induced apoptotic cell death. Most importantly, in vivo radiation protection was observed in mice whether TAT-BH4 treatment was given prior to or after irradiation. Thus, by targeting steps within the apoptosis signaling pathway it is possible to develop post-exposure treatments to protect radio-sensitive tissues

Building Capacity in Using Earth Observations Under the GOFC-GOLD and TAT Programs

Science.gov (United States)

Gutman, G.

2015-12-01

The Global Observation of Forest and Land Cover Dynamics (GOFC-GOLD) is a coordinated international effort to provide ongoing space-based and in-situ observations of forests and other vegetation cover. The main goal of GOFC/GOLD is to support a forum for international information exchange, observation and data coordination, and a framework for establishing the necessary long-term monitoring systems. GOFC-GOLD has two Implementation Teams: Land Cover Characteristics and Change, and Fire Monitoring and Mapping. Additionally, it includes two working groups: the Working Group on Biomass Monitoring and the Working group on Reducing Emissions from Deforestation and Forest Degradation (REDD), the latter being aligned with the United Nations Framework Convention on Climate Change. Regional networks are an integral part of the GOFC-GOLD program, with some networks fully developed and some still emerging. GOFC-GOLD provides training workshops to build capacity in the regions. Capacity building in using Earth Observation techniques and applications is also promoted by cooperation of NASA and ESA under the Trans-Atlantic Training (TAT) program. The main objective of TAT is training of early career scientists and students in East European and Baltic countries emphasizing outstanding technical issues in remote sensing of land-cover/land-use change and ecosystems processes. TAT promotes data sharing and advanced research methods and technologies through series of training sessions. Three TAT sessions have been held until now, each session consisting of 5-10 tutors and about 30 early career scientists and students from Eastern Europe. The sessions include lectures on remote sensing covering the full solar spectrum and hands-on practice. The experience obtained in capacity building activities under GOFC-GOLD and TAT will be shared with the audience.

The human immunodeficiency virus-1 protein Tat and its discrete fragments evoke selective release of acetylcholine from human and rat cerebrocortical terminals through species-specific mechanisms.

Science.gov (United States)

Feligioni, Marco; Raiteri, Luca; Pattarini, Roberto; Grilli, Massimo; Bruzzone, Santina; Cavazzani, Paolo; Raiteri, Maurizio; Pittaluga, Anna

2003-07-30

The effect of the human immunodeficiency virus-1 protein Tat was investigated on neurotransmitter release from human and rat cortical nerve endings. Tat failed to affect the release of several neurotransmitters, such as glutamate, GABA, norepinephrine, and others, but it evoked the release of [3H]ACh via increase of cytosolic [Ca2+]. In human nerve terminals, the Tat effect partly depends on Ca2+ entry through voltage-sensitive Ca2+ channels, because Cd2+ halved the Tat-evoked release. Activation of group I metabotropic glutamate receptors (mGluR) and mobilization of Ca2+ from IP3-sensitive intraterminal stores are also involved, because the Tat effect was prevented by mGluR antagonists 2-methyl-6-(phenylethynyl)pyridine hydrochloride and 7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxylate ethyl ester and by the IP3 receptor antagonists heparin and xestospongin C. Furthermore, the group I selective mGlu agonist (RS)-3,5-dihydroxyphenylglycine enhanced [3H]ACh release. In rat nerve terminals, the Tat-evoked release neither depends on external Ca2+ ions entry nor on IP3-mediated mechanisms. Tat seems to cause mobilization of Ca2+ from ryanodine-sensitive internal stores because its effect was prevented by both 8-bromo-cyclic adenosine diphosphate-ribose and dantrolene. The Tat-evoked release from human synaptosomes was mimicked by the peptide sequences Tat 32-62, Tat 49-86, and Tat 41-60. In contrast, the Tat 49-86 and Tat 61-80 fragments, but not the Tat 32-62 fragment, were active in rat synaptosomes. In conclusion, Tat elicits Ca2+-dependent [3H]ACh release by species-specific intraterminal mechanisms by binding via discrete amino acid sequences to different receptive sites on human and rat cholinergic terminals.

Characterization of gene expression regulated by human OTK18 ...

Indian Academy of Sciences (India)

ing regulated by interactions with the Tat protein (Carlson et al. 2004a). In contrast, OTK18 is ubiquitously expressed in all normal human tissues, and OTK18 expression in HIV-1 ..... and Social Sciences and the UNK Biology Department.

Subtypes of coups d’état: recent transformations of a 17th century concept

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Rafael Martínez

2014-12-01

Full Text Available Ostensibly, the coup d’état as a practice has been virtually eradicated, or confined, at least, to failed African states. Nevertheless, in recent years various changes of government in Latin America (and even Europe have provoked serious doubts to be raised as to their legality and legitimacy, and they have come to be regarded as coups d’état. In light of this reality, this study attempts to go deeper into the concept of the coup d’état, right through from its creation in the 17th century to our times, in order to determine the evolutionary changes that the concept has undergone and to extract the lowest common denominator that has remained unchanged. With these premises established, the presumed evolutionary course of the concept in the 21st century is plotted and the typologies it might generate are proposed.

Tat protein vaccination of cynomolgus macaques influences SHIV-89.6P cy243 epitope variability.

Science.gov (United States)

Ridolfi, Barbara; Genovese, Domenico; Argentini, Claudio; Maggiorella, Maria Teresa; Sernicola, Leonardo; Buttò, Stefano; Titti, Fausto; Borsetti, Alessandra; Ensoli, Barbara

2008-02-01

In a previous study we showed that vaccination with the native Tat protein controlled virus replication in five out of seven monkeys against challenge with the simian human immunodeficiency virus (SHIV)-89.6P cy243 and that this protection correlated with T helper (Th)-1 response and cytotoxic T lymphocyte (CTL) activity. To address the evolution of the SHIV-89.6P cy243 both in control and vaccinated infected monkeys, the sequence of the human immunodeficiency virus (HIV)-1 Tat protein and the C2-V3 Env region of the proviral-DNA-derived clones were analyzed in both control and vaccinated but unprotected animals. We also performed analysis of the T cell epitope using a predictive epitope model taking into consideration the phylogeny of the variants. Our results suggest that even though the viral evolution observed in both groups of monkeys was directed toward variations in the major histocompatibility complex (MHC)-I epitopes, in the control animals it was associated with mutational escape of such epitopes. On the contrary, it is possible that viral evolution in the vaccinated monkeys was linked to mutations that arose to keep high the viral fitness. In the vaccinated animals the reduction of epitope variability, obtained prompting the immune system by vaccination and inducing a specific immunological response against virus, was able to reduce the emergence of escape mutants. Thus the intervention of host's selective forces in driving CTL escape mutants and in modulating viral fitness appeared to be different in the two groups of monkeys. We concluded that in the vaccinated unprotected animals, vaccination with the Tat protein induced a broad antiviral response, as demonstrated by the reduced ability to develop escape mutants, which is known to help in the control of viral replication.

Iran : l’État islamique entre structures monopolistiques et modèle de l’État social

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Azadeh Kian-Thiébaut

2012-01-01

Full Text Available Dans l’Iran post-révolutionnaire, la segmentation de la société s’est amplifiée, l’économie est demeurée rentière et l’État, privatisé, sert avant tout les intérêts des structures monopolistiques, formées à la suite de la création des fondations révolutionnaires, de l’étatisation de l’économie et de sa réorientation vers le secteur de distribution. Le poids de ces fondations, dirigées par les conservateurs, qui jouissent d’un statut autonome et contrôlent une partie importante du PIB s’étend aussi à la sphère politique. D’où l’échec des tentatives d’une réforme structurelle profonde, en dépit de l’évolution de l’économie stato-centrée des dix premières années, établie sous l’impulsion des acteurs sociaux et économiques radicaux, vers une économie de marché. Face à la crise économique et au chômage massif, le gouvernement, soucieux de la fragilisation de la cohésion sociale, se rapproche du modèle de l’État social en optant pour une politique sociale dont les dépenses sont financées par les revenus pétroliers et non par la taxation et la solidarité. Ce qui risque d’entraver l’autonomisation de la population assistée et d’amoindrir l’influence qu’elle peut exercer sur l’État.Confrontée au verrouillage du système politique et animée par une volonté de participation sociale visant à introduire un changement par le bas, la société civile émergente, en particulier les classes moyennes, s’engage davantage dans l’activité sociale à travers des réseaux traditionnels et modernes d’entraide. Cette participation sociale est susceptible d’assurer, à terme, les conditions de développement des sphères de l’autonomie sociale.

A non-genetic approach to labelling acute myeloid leukemia and bone marrow cells with quantum dots.

Science.gov (United States)

Zheng, Yanwen; Tan, Dongming; Chen, Zheng; Hu, Chenxi; Mao, Zhengwei J; Singleton, Timothy P; Zeng, Yan; Shao, Xuejun; Yin, Bin

2014-06-01

The difficulty in manipulation of leukemia cells has long hindered the dissection of leukemia pathogenesis. We have introduced a non-genetic approach of marking blood cells, using quantum dots. We compared quantum dots complexed with different vehicles, including a peptide Tat, cationic polymer Turbofect and liposome. Quantum dots-Tat showed the highest efficiency of marking hematopoietic cells among the three vehicles. Quantum dots-Tat could also label a panel of leukemia cell lines at varied efficiencies. More uniform intracellular distributions of quantum dots in mouse bone marrow and leukemia cells were obtained with quantum dots-Tat, compared with the granule-like formation obtained with quantum dots-liposome. Our results suggest that quantum dots have provided a photostable and non-genetic approach that labels normal and malignant hematopoietic cells, in a cell type-, vehicle-, and quantum dot concentration-dependent manner. We expect for potential applications of quantum dots as an easy and fast marking tool assisting investigations of various types of blood cells in the future.

Cellular Uptake and Photo-Cytotoxicity of a Gadolinium(III-DOTA-Naphthalimide Complex “Clicked” to a Lipidated Tat Peptide

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William I. O’Malley

2016-02-01

Full Text Available A new bifunctional macrocyclic chelator featuring a conjugatable alkynyl-naphthalimide fluorophore pendant group has been prepared and its Gd(III complex coupled to a cell-penetrating lipidated azido-Tat peptide derivative using Cu(I-catalysed “click” chemistry. The resulting fluorescent conjugate is able to enter CAL-33 tongue squamous carcinoma cells, as revealed by confocal microscopy, producing a very modest anti-proliferative effect (IC50 = 93 µM. Due to the photo-reactivity of the naphthalimide moiety, however, the conjugate’s cytotoxicity is significantly enhanced (IC50 = 16 µM upon brief low-power UV-A irradiation.

Inhibition of NF-κB by a cell permeable form of IκBα induces apoptosis in eosinophils

International Nuclear Information System (INIS)

Fujihara, Satoko; Jaffray, Ellis; Farrow, Stuart N.; Rossi, Adriano G.; Haslett, Christopher; Hay, Ronald T.

2005-01-01

An 11 amino acid HIV-TAT peptide can deliver target proteins into a variety of cells in a receptor-independent manner. To generate a highly specific inhibitor of the transcription factor NF-κB, we have fused the TAT-peptide to a version of IκBα that is resistant to signal-induced degradation. TAT-IκBα(S32A, S36A) inhibited NF-κB-dependent transcription in HeLa and A549 cells by retaining NF-κB p65 in the cytoplasm. Introduction of TAT-IκBα(S32A, S36A) into human eosinophils inhibited the nuclear translocation of NF-κB and induced apoptosis. Thus, continuous NF-κB-dependent transcription is important for eosinophil survival. While eosinophils are normally refractive to standard methods of gene delivery, the ability of TAT fusion proteins to be taken up by these cells should enable a detailed molecular analysis of survival pathways in these cells

Human immunodeficiency virus long terminal repeat responds to T-cell activation signals

International Nuclear Information System (INIS)

Tong-Starksen, S.E.; Luciw, P.A.; Peterlin, B.M.

1987-01-01

Human immunodeficiency virus (HIV), the causative agent of AIDS, infects and kills lymphoid cells bearing the CD4 antigen. In an infected cell, a number of cellular as well as HIV-encoded gene products determine the levels of viral gene expression and HIV replication. Efficient HIV replication occurs in activated T cells. Utilizing transient expression assays, the authors show that gene expression directed by the HIV long terminal repeat (LTR) increases in response to T-cell activation signals. The effects of T-cell activation and of the HIV-encoded trans-activator (TAT) are multiplicative. Analysis of mutations and deletions in the HIV LTR reveals that the region responding to T-cell activation signals is located at positions -105 to -80. These sequences are composed of two direct repeats, which are homologous to the core transcriptional enhancer elements in the simian virus 40 genome. The studies reveal that these elements function as the HIV enhancer. By acting directly on the HIV LTR, T-cell activation may play an important role in HIV gene expression and in the activation of latent HIV

Cellular Reprogramming Employing Recombinant Sox2 Protein

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Marc Thier

2012-01-01

Full Text Available Induced pluripotent stem (iPS cells represent an attractive option for the derivation of patient-specific pluripotent cells for cell replacement therapies as well as disease modeling. To become clinically meaningful, safe iPS cells need to be generated exhibiting no permanent genetic modifications that are caused by viral integrations of the reprogramming transgenes. Recently, various experimental strategies have been applied to accomplish transgene-free derivation of iPS cells, including the use of nonintegrating viruses, episomal expression, or excision of transgenes after reprogramming by site-specific recombinases or transposases. A straightforward approach to induce reprogramming factors is the direct delivery of either synthetic mRNA or biologically active proteins. We previously reported the generation of cell-permeant versions of Oct4 (Oct4-TAT and Sox2 (Sox2-TAT proteins and showed that Oct4-TAT is reprogramming-competent, that is, it can substitute for Oct4-encoding virus. Here, we explore conditions for enhanced Sox2-TAT protein stabilization and functional delivery into somatic cells. We show that cell-permeant Sox2 protein can be stabilized by lipid-rich albumin supplements in serum replacement or low-serum-supplemented media. Employing optimized conditions for protein delivery, we demonstrate that Sox2-TAT protein is able to substitute for viral Sox2. Sox2-piPS cells express pluripotency-associated markers and differentiate into all three germ layers.

Structure-based design of ligands for protein basic domains: Application to the HIV-1 Tat protein

Science.gov (United States)

Filikov, Anton V.; James, Thomas L.

1998-05-01

A methodology has been developed for designing ligands to bind a flexible basic protein domain where the structure of the domain is essentially known. It is based on an empirical binding free energy function developed for highly charged complexes and on Monte Carlo simulations in internal coordinates with both the ligand and the receptor being flexible. HIV-1 encodes a transactivating regulatory protein called Tat. Binding of the basic domain of Tat to TAR RNA is required for efficient transcription of the viral genome. The structure of a biologically active peptide containing the Tat basic RNA-binding domain is available from NMR studies. The goal of the current project is to design a ligand which will bind to that basic domain and potentially inhibit the TAR-Tat interaction. The basic domain contains six arginine and two lysine residues. Our strategy was to design a ligand for arginine first and then a superligand for the basic domain by joining arginine ligands with a linker. Several possible arginine ligands were obtained by searching the Available Chemicals Directory with DOCK 3.5 software. Phytic acid, which can potentially bind multiple arginines, was chosen as a building block for the superligand. Calorimetric binding studies of several compounds to methylguanidine and Arg-/Lys-containing peptides were performed. The data were used to develop an empirical binding free energy function for prediction of affinity of the ligands for the Tat basic domain. Modeling of the conformations of the complexes with both the superligand and the basic domain being flexible has been carried out via Biased Probability Monte Carlo (BPMC) simulations in internal coordinates (ICM 2.6 suite of programs). The simulations used parameters to ensure correct folding, i.e., consistent with the experimental NMR structure of a 25-residue Tat peptide, from a random starting conformation. Superligands for the basic domain were designed by joining together two molecules of phytic acid with

Phenobarbital reduces blood glucose and gluconeogenesis through down-regulation of phosphoenolpyruvate carboxykinase (GTP) gene expression in rats.

Science.gov (United States)

Oda, Hiroaki; Okuda, Yuji; Yoshida, Yukiko; Kimura, Noriko; Kakinuma, Atsushi

2015-10-23

The regulatory mechanism of phosphoenolpyruvate carboykinase (GTP) (EC 4.1.1.32) (PEPCK) gene expression and gluconeogenesis by phenobarbital (PB), which is known to induce drug-metabolizing enzymes, was investigated. Higher level of PEPCK mRNA was observed in spherical rat primary hepatocytes on EHS-gel than monolayer hepatocytes on TIC (type I collagen). We found that PB directly suppressed PEPCK gene expression in spherical hepatocytes on EHS-gel, but not in those on TIC. PB strongly suppressed cAMP-dependent induction of PEPCK gene expression. Tyrosine aminotransferase (TAT), another gluconeogenic enzyme, was induced by cAMP, but not suppressed by PB. Chronic administration of PB reduced hepatic PEPCK mRNA in streptozotocin-induced diabetic and nondiabetic rats, and PB reduced blood glucose level in diabetic rats. Increased TAT mRNA in diabetic rats was not suppressed by PB. These results indicated that PB-dependent reduction is specific to PEPCK. From pyrvate challenge test, PB suppressed the increased gluconeogenesis in diabetic rats. PEPCK gene promoter activity was suppressed by PB in HepG2 cells. In conclusion, we found that spherical hepatocytes cultured on EHS-gel are capable to respond to PB to suppress PEPCK gene expression. Moreover, our results indicate that hypoglycemic action of PB result from transcriptional repression of PEPCK gene and subsequent suppression of gluconeogenesis. Copyright © 2015. Published by Elsevier Inc.

Backbone dynamics of the EIAV-Tat protein from 15N relaxation studies

International Nuclear Information System (INIS)

Ejchart, A.; Herrmann, F.; Roesch, P.; Sticht, H.; Willbold, D.

1994-01-01

The work investigates the mobility of EIAV-Tat protein backbone by measuring the relaxation parameters of the 15 N nitrogens. High degree of the flexibility, non-typical of rigid, well structured proteins was shown

Human cyclin T1 expression ameliorates a T-cell-specific transcriptional limitation for HIV in transgenic rats, but is not sufficient for a spreading infection of prototypic R5 HIV-1 strains ex vivo

Directory of Open Access Journals (Sweden)

Littman Dan R

2009-01-01

Full Text Available Abstract Background Cells derived from native rodents have limits at distinct steps of HIV replication. Rat primary CD4 T-cells, but not macrophages, display a profound transcriptional deficit that is ameliorated by transient trans-complementation with the human Tat-interacting protein Cyclin T1 (hCycT1. Results Here, we generated transgenic rats that selectively express hCycT1 in CD4 T-cells and macrophages. hCycT1 expression in rat T-cells boosted early HIV gene expression to levels approaching those in infected primary human T-cells. hCycT1 expression was necessary, but not sufficient, to enhance HIV transcription in T-cells from individual transgenic animals, indicating that endogenous cellular factors are critical co-regulators of HIV gene expression in rats. T-cells from hCD4/hCCR5/hCycT1-transgenic rats did not support productive infection of prototypic wild-type R5 HIV-1 strains ex vivo, suggesting one or more significant limitation in the late phase of the replication cycle in this primary rodent cell type. Remarkably, we identify a replication-competent HIV-1 GFP reporter strain (R7/3 YU-2 Env that displays characteristics of a spreading, primarily cell-to-cell-mediated infection in primary T-cells from hCD4/hCCR5-transgenic rats. Moreover, the replication of this recombinant HIV-1 strain was significantly enhanced by hCycT1 transgenesis. The viral determinants of this so far unique replicative ability are currently unknown. Conclusion Thus, hCycT1 expression is beneficial to de novo HIV infection in a transgenic rat model, but additional genetic manipulations of the host or virus are required to achieve full permissivity.

Detecting protein-protein interactions in living cells

DEFF Research Database (Denmark)

Gottschalk, Marie; Bach, Anders; Hansen, Jakob Lerche

2009-01-01

to the endogenous C-terminal peptide of the NMDA receptor, as evaluated by a cell-free protein-protein interaction assay. However, it is important to address both membrane permeability and effect in living cells. Therefore a bioluminescence resonance energy transfer (BRET) assay was established, where the C......-terminal of the NMDA receptor and PDZ2 of PSD-95 were fused to green fluorescent protein (GFP) and Renilla luciferase (Rluc) and expressed in COS7 cells. A robust and specific BRET signal was obtained by expression of the appropriate partner proteins and subsequently, the assay was used to evaluate a Tat......The PDZ domain mediated interaction between the NMDA receptor and its intracellular scaffolding protein, PSD-95, is a potential target for treatment of ischemic brain diseases. We have recently developed a number of peptide analogues with improved affinity for the PDZ domains of PSD-95 compared...

Improving enzymatic activities and thermostability of a tri-functional enzyme with SOD, catalase and cell-permeable activities.

Science.gov (United States)

Luangwattananun, Piriya; Eiamphungporn, Warawan; Songtawee, Napat; Bülow, Leif; Isarankura Na Ayudhya, Chartchalerm; Prachayasittikul, Virapong; Yainoy, Sakda

2017-04-10

Synergistic action of major antioxidant enzymes, e.g., superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) is known to be more effective than the action of any single enzyme. Recently, we have engineered a tri-functional enzyme, 6His-MnSOD-TAT/CAT-MnSOD (M-TAT/CM), with SOD, CAT and cell-permeable activities. The protein actively internalized into the cells and showed superior protection against oxidative stress-induced cell death over native enzymes fused with TAT. To improve its molecular size, enzymatic activity and stability, in this study, MnSOD portions of the engineered protein were replaced by CuZnSOD, which is the smallest and the most heat resistant SOD isoform. The newly engineered protein, CAT-CuZnSOD/6His-CuZnSOD-TAT (CS/S-TAT), had a 42% reduction in molecular size and an increase in SOD and CAT activities by 22% and 99%, respectively. After incubation at 70°C for 10min, the CS/S-TAT retained residual SOD activity up to 54% while SOD activity of the M-TAT/CM was completely abolished. Moreover, the protein exhibited a 5-fold improvement in half-life at 70°C. Thus, this work provides insights into the design and synthesis of a smaller but much more stable multifunctional antioxidant enzyme with ability to enter mammalian cells for further application as protective/therapeutic agent against oxidative stress-related conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

Genetic incorporation of the protein transduction domain of Tat into Ad5 fiber enhances gene transfer efficacy

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Siegal Gene P

2007-10-01

Full Text Available Abstract Background Human adenovirus serotype 5 (Ad5 has been widely explored as a gene delivery vector for a variety of diseases. Many target cells, however, express low levels of Ad5 native receptor, the Coxsackie-Adenovirus Receptor (CAR, and thus are resistant to Ad5 infection. The Protein Transduction Domain of the HIV Tat protein, namely PTDtat, has been shown to mediate protein transduction in a wide range of cells. We hypothesize that re-targeting Ad5 vector via the PTDtat motif would improve the efficacy of Ad5-mediated gene delivery. Results In this study, we genetically incorporated the PTDtat motif into the knob domain of Ad5 fiber, and rescued the resultant viral vector, Ad5.PTDtat. Our data showed the modification did not interfere with Ad5 binding to its native receptor CAR, suggesting Ad5 infection via the CAR pathway is retained. In addition, we found that Ad5.PTDtat exhibited enhanced gene transfer efficacy in all of the cell lines that we have tested, which included both low-CAR and high-CAR decorated cells. Competitive inhibition assays suggested the enhanced infectivity of Ad5.PTDtat was mediated by binding of the positively charged PTDtat peptide to the negatively charged epitopes on the cells' surface. Furthermore, we investigated in vivo gene delivery efficacy of Ad5.PTDtat using subcutaneous tumor models established with U118MG glioma cells, and found that Ad5.PTDtat exhibited enhanced gene transfer efficacy compared to unmodified Ad5 vector as analyzed by a non-invasive fluorescence imaging technique. Conclusion Genetic incorporation of the PTDtat motif into Ad5 fiber allowed Ad5 vectors to infect cells via an alternative PTDtat targeting motif while retaining the native CAR-mediated infection pathway. The enhanced infectivity was demonstrated in both cultured cells and in in vivo tumor models. Taken together, our study identifies a novel tropism expanded Ad5 vector that may be useful for clinical gene therapy

Nuclear retention of multiply spliced HIV-1 RNA in resting CD4+ T cells.

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Kara G Lassen

2006-07-01

Full Text Available HIV-1 latency in resting CD4+ T cells represents a major barrier to virus eradication in patients on highly active antiretroviral therapy (HAART. We describe here a novel post-transcriptional block in HIV-1 gene expression in resting CD4+ T cells from patients on HAART. This block involves the aberrant localization of multiply spliced (MS HIV-1 RNAs encoding the critical positive regulators Tat and Rev. Although these RNAs had no previously described export defect, we show that they exhibit strict nuclear localization in resting CD4+ T cells from patients on HAART. Overexpression of the transcriptional activator Tat from non-HIV vectors allowed virus production in these cells. Thus, the nuclear retention of MS HIV-1 RNA interrupts a positive feedback loop and contributes to the non-productive nature of infection of resting CD4+ T cells. To define the mechanism of nuclear retention, proteomic analysis was used to identify proteins that bind MS HIV-1 RNA. Polypyrimidine tract binding protein (PTB was identified as an HIV-1 RNA-binding protein differentially expressed in resting and activated CD4+ T cells. Overexpression of PTB in resting CD4+ T cells from patients on HAART allowed cytoplasmic accumulation of HIV-1 RNAs. PTB overexpression also induced virus production by resting CD4+ T cells. Virus culture experiments showed that overexpression of PTB in resting CD4+ T cells from patients on HAART allowed release of replication-competent virus, while preserving a resting cellular phenotype. Whether through effects on RNA export or another mechanism, the ability of PTB to reverse latency without inducing cellular activation is a result with therapeutic implications.

Ireland's Preparedness for Nuclear Emergencies - Development of a Handbook for the Technical Assessment Team (TAT)

Energy Technology Data Exchange (ETDEWEB)

Organo, Catherine; Smith, Kilian; Smith, Veronica; O' Connor, Collette; McMahon, Ciara [Environmental Protection Agency, Office of Radiological Protection, 3 Clonskeagh Square, Clonskeagh Road, Dublin 14 (Ireland)

2014-07-01

In Ireland, the National Emergency Plan for Nuclear Accidents (NEPNA) provides a framework for the national response to a large scale nuclear incident with the potential to contaminate a wide area. Under this plan, the Radiological Protection Institute of Ireland (RPII) has been assigned a major role covering a range of responsibilities. One of these is to carry out a radiological assessment of the situation. The RPII Technical Assessment Team (TAT) is activated in such circumstances, and is tasked with delivering this radiological assessment. Broadly speaking, the role of the TAT is to gather together all of the available information relevant to the event and to use this information to assess the radiological consequences for Ireland so as to formulate advice regarding subsequent precautionary actions, particular regarding food controls and preventive measures for the agricultural sectors. The TAT could also be asked to assess the radiological consequences for Irish citizens abroad, living in any location potentially affected by radioactive contamination. The arrangements for the running of the TAT are set out in the TAT handbook. This document has been under developed for a number of years and is now undergoing a major revision. A large number of additional documents have been developed since the original draft version was produced and, in conjunction with RPII's experience in responding to real events and exercises these need to be integrated and taken into account to produce an updated version. This poster will explain the rationale behind the review; it will outline the planning process and describe the various implementation phases, from the inventory of the existing documents and procedures to the integration of the new information that need to be considered during the response to an emergency. An outline of some of the key procedures being developed will also be given. (authors)

Comparative analysis of twin-arginine (Tat)-dependent protein secretion of a heterologous model protein (GFP) in three different Gram-positive bacteria

NARCIS (Netherlands)

Meissner, Daniel; Vollstedt, Angela; van Dijl, Jan Maarten; Freudl, Roland

In contrast to the general protein secretion (Sec) system, the twin-arginine translocation (Tat) export pathway allows the translocation of proteins across the bacterial plasma membrane in a fully folded conformation. Due to this feature, the Tat pathway provides an attractive alternative to the

Expression of heparanase in basal cell carcinoma and squamous cell carcinoma.

Science.gov (United States)

Pinhal, Maria Aparecida Silva; Almeida, Maria Carolina Leal; Costa, Alessandra Scorse; Theodoro, Thérèse Rachell; Serrano, Rodrigo Lorenzetti; Machado, Carlos D'Apparecida Santos

2016-01-01

Heparanase is an enzyme that cleaves heparan sulfate chains. Oligosaccharides generated by heparanase induce tumor progression. Basal cell carcinoma and squamous cell carcinoma comprise types of nonmelanoma skin cancer. Evaluate the glycosaminoglycans profile and expression of heparanase in two human cell lines established in culture, immortalized skin keratinocyte (HaCaT) and squamous cell carcinoma (A431) and also investigate the expression of heparanase in basal cell carcinoma, squamous cell carcinoma and eyelid skin of individuals not affected by the disease (control). Glycosaminoglycans were quantified by electrophoresis and indirect ELISA method. The heparanase expression was analyzed by quantitative RT-PCR (qRTPCR). The A431 strain showed significant increase in the sulfated glycosaminoglycans, increased heparanase expression and decreased hyaluronic acid, comparing to the HaCaT lineage. The mRNA expression of heparanase was significantly higher in Basal cell carcinoma and squamous cell carcinoma compared with control skin samples. It was also observed increased heparanase expression in squamous cell carcinoma compared to the Basal cell carcinoma. The glycosaminoglycans profile, as well as heparanase expression are different between HaCaT and A431 cell lines. The increased expression of heparanase in Basal cell carcinoma and squamous cell carcinoma suggests that this enzyme could be a marker for the diagnosis of such types of non-melanoma cancers, and may be useful as a target molecule for future alternative treatment.

Sprouty regulates cell migration by inhibiting the activation of Rac1 GTPase

International Nuclear Information System (INIS)

Poppleton, Helen M.; Edwin, Francis; Jaggar, Laura; Ray, Ramesh; Johnson, Leonard R.; Patel, Tarun B.

2004-01-01

Sprouty (SPRY) protein negatively modulates fibroblast growth factor and epidermal growth factor actions. We showed that human SPRY2 inhibits cell growth and migration in response to serum and several growth factors. Using rat intestinal epithelial (IEC-6) cells, we investigated the involvement of the Rho family of GTPases, RhoA, Rac1, and cdc42 in SPRY2-mediated inhibition of cell migration and proliferation. The ability of TAT-tagged SPRY2 to inhibit proliferation and migration of IEC-6 cells transfected with constitutively active mutants of RhoA(G14V), Rac1(G12V), and cdc42 (F28L) was determined. Constitutively active RhoA(G14V), Rac1(G12V), or cdc42(F28L) did not protect cells from the anti-proliferative actions of TAT-SPRY2. The ability of TAT-hSPRY2 to inhibit migration was not altered by of RhoA(G14V) and cdc42(F28L). However, Rac1(G12V) obliterated the ability of SPRY2 to inhibit cell autonomous or serum-induced migration. Also, the activation of endogenous Rac1 was attenuated by TAT-SPRY2. Thus, SPRY2 mediates its anti-migratory actions by inhibiting Rac1 activation

Interplay between Structure and Charge as a Key to Allosteric Modulation of Human 20S Proteasome by the Basic Fragment of HIV-1 Tat Protein.

Directory of Open Access Journals (Sweden)

Przemysław Karpowicz

Full Text Available The proteasome is a giant protease responsible for degradation of the majority of cytosolic proteins. Competitive inhibitors of the proteasome are used against aggressive blood cancers. However, broadening the use of proteasome-targeting drugs requires new mechanistic approaches to the enzyme's inhibition. In our previous studies we described Tat1 peptide, an allosteric inhibitor of the proteasome derived from a fragment of the basic domain of HIV-Tat1 protein. Here, we attempted to dissect the structural determinants of the proteasome inhibition by Tat1. Single- and multiple- alanine walking scans were performed. Tat1 analogs with stabilized beta-turn conformation at positions 4-5 and 8-9, pointed out by the molecular dynamics modeling and the alanine scan, were synthesized. Structure of Tat1 analogs were analyzed by circular dichroism, Fourier transform infrared and nuclear magnetic resonance spectroscopy studies, supplemented by molecular dynamics simulations. Biological activity tests and structural studies revealed that high flexibility and exposed positive charge are hallmarks of Tat1 peptide. Interestingly, stabilization of a beta-turn at the 8-9 position was necessary to significantly improve the inhibitory potency.

Calcium ions effectively enhance the effect of antisense peptide nucleic acids conjugated to cationic tat and oligoarginine peptides

DEFF Research Database (Denmark)

Shiraishi, Takehiko; Pankratova, Stanislava; Nielsen, Peter E

2005-01-01

Cell-penetrating peptides have been widely used to improve cellular delivery of a variety of proteins and antisense agents. However, recent studies indicate that such cationic peptides are predominantly entering cells via an endosomal pathway. We now show that the nuclear antisense effect in He......La cells of a variety of peptide nucleic acid (PNA) peptide conjugates is significantly enhanced by addition of 6 mM Ca(2+) (as well as by the lysosomotrophic agent chloroquine). In particular, the antisense activities of Tat(48-60) and heptaarginine-conjugated PNAs were increased 44-fold and 8.5-fold......, respectively. Evidence is presented that the mechanism involves endosomal release. The present results show that Ca(2+) can be used as an effective enhancer for in vitro cellular delivery of cationic peptide-conjugated PNA oligomers, and also emphasize the significance of the endosomal escape route...

Multi-functional system of radiotherapy and thermal phototherapy for tumors that over-express receptors of the gastrin releasing peptide

International Nuclear Information System (INIS)

Jimenez M, N. P.

2014-01-01

purity was 96 ± 2%, no further purification was necessary. In vitro studies showed that after laser irradiation, the presence of AuNP-Tat-Bn caused a significant increase in the temperature of the medium (46.4 grades C vs. 39.5 grades C of that without AuNP) resulting in a significant decrease in PC3 cell viability down to 1.3 %. In the in vivo studies the 177 Lu/ 99m Tc-AuNP-Tat-Bn showed a biological residence time of 80.6 h. The radiation absorbed doses from 177 Lu and 99m Tc to the tumor after normalization to the unit of administered activity were 7.90 ± 0.95 Gy/MBq and 0.07±0.01 Gy/MBq, respectively. Fluorescent images showed that the system was internalized into the nucleus of PC3 cells. The 177 Lu/ 99m Tc-AuNP-Tat-Bn system showed properties suitable for a targeted radionuclide therapy of tumours expressing GRP receptors due to the energy deposition from β-emissions and the Auger and internal conversion electron emissions near the DNA. It has potential application in medical diagnosis and therapeutic treatments due to its unique combination of radioactive, optical and thermo ablative properties, therefore, this study demonstrated that the nano system exhibited properties that are suitable for plasmonic photothermal therapy and targeted radiotherapy in the treatment of prostate cancer. (Author)

Chemical Composition of Essential Oils from Thymus vulgaris, Cymbopogon citratus, and Rosmarinus officinalis, and Their Effects on the HIV-1 Tat Protein Function.

Science.gov (United States)

Feriotto, Giordana; Marchetti, Nicola; Costa, Valentina; Beninati, Simone; Tagliati, Federico; Mischiati, Carlo

2018-02-01

New drugs would be beneficial to fight resistant HIV strains, in particular those capable of interfering with essential viral functions other than those targeted by highly active antiretroviral therapy drugs. Despite the central role played by Tat protein in HIV transcription, a search for vegetable extracts able to hamper this important viral function was never carried out. In this work, we evaluated the chemical composition and possible interference of essential oil from Thymus vulgaris, Cananga odorata, Cymbopogon citratus, and Rosmarinus officinalis with the Tat/TAR-RNA interaction and with Tat-induced HIV-1 LTR transcription. GC/MS Analysis demonstrated the biodiversity of herbal species translated into essential oils composed of different blends of terpenes. In all of them, 4 - 6 constituents represent from 81.63% to 95.19% of the total terpenes. Essential oils of Thymus vulgaris, Cymbopogon citratus, and Rosmarinus officinalis were active in interfering with Tat functions, encouraging further studies to identify single terpenes responsible for the antiviral activity. In view of the quite different composition of these essential oils, we concluded that their interference on Tat function depends on specific terpene or a characteristic blend. © 2018 Wiley-VHCA AG, Zurich, Switzerland.

PSD-95 uncoupling from NMDA receptors by Tat-N-dimer ameliorates neuronal depolarisation in cortical spreading depression

DEFF Research Database (Denmark)

Kucharz, Krzysztof; Søndergaard Rasmussen, Ida; Bach, Anders

2017-01-01

during the first hour after i.v. injection. The Tat-N-dimer suppressed stimulation-evoked synaptic activity by 2-20%, while cortical blood flow and cerebral oxygen metabolic (CMRO2) responses were preserved. During cortical spreading depression, the Tat-N-dimer reduced the average amplitude...... depression on cortical blood flow and CMRO2 We suggest that uncoupling of PSD-95 from NMDA receptors reduces overall neuronal excitability and the amplitude of the spreading depolarisation wave. These findings may be of interest for understanding the neuroprotective effects of the nNOS/PSD-95 uncoupling...

Fractalkine expression induces endothelial progenitor cell lysis by natural killer cells.

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Dilyana Todorova

Full Text Available BACKGROUND: Circulating CD34(+ cells, a population that includes endothelial progenitors, participate in the maintenance of endothelial integrity. Better understanding of the mechanisms that regulate their survival is crucial to improve their regenerative activity in cardiovascular and renal diseases. Chemokine-receptor cross talk is critical in regulating cell homeostasis. We hypothesized that cell surface expression of the chemokine fractalkine (FKN could target progenitor cell injury by Natural Killer (NK cells, thereby limiting their availability for vascular repair. METHODOLOGY/PRINCIPAL FINDINGS: We show that CD34(+-derived Endothelial Colony Forming Cells (ECFC can express FKN in response to TNF-α and IFN-γ inflammatory cytokines and that FKN expression by ECFC stimulates NK cell adhesion, NK cell-mediated ECFC lysis and microparticles release in vitro. The specific involvement of membrane FKN in these processes was demonstrated using FKN-transfected ECFC and anti-FKN blocking antibody. FKN expression was also evidenced on circulating CD34(+ progenitor cells and was detected at higher frequency in kidney transplant recipients, when compared to healthy controls. The proportion of CD34(+ cells expressing FKN was identified as an independent variable inversely correlated to CD34(+ progenitor cell count. We further showed that treatment of CD34(+ circulating cells isolated from adult blood donors with transplant serum or TNF-α/IFN-γ can induce FKN expression. CONCLUSIONS: Our data highlights a novel mechanism by which FKN expression on CD34(+ progenitor cells may target their NK cell mediated killing and participate to their immune depletion in transplant recipients. Considering the numerous diseased contexts shown to promote FKN expression, our data identify FKN as a hallmark of altered progenitor cell homeostasis with potential implications in better evaluation of vascular repair in patients.

A novel chimeric cell-penetrating peptide with membrane-disruptive properties for efficient endosomal escape.

Science.gov (United States)

Salomone, Fabrizio; Cardarelli, Francesco; Di Luca, Mariagrazia; Boccardi, Claudia; Nifosì, Riccardo; Bardi, Giuseppe; Di Bari, Lorenzo; Serresi, Michela; Beltram, Fabio

2012-11-10

Efficient endocytosis into a wide range of target cells and low toxicity make the arginine-rich Tat peptide (Tat(11): YGRKKRRQRRR, residues 47-57 of HIV-1 Tat protein) an excellent transporter for delivery purposes. Unfortunately, molecules taken up by endocytosis undergo endosomal entrapment and possible metabolic degradation. Escape from the endosome is therefore actively researched. In this context, antimicrobial peptides (AMPs) provide viable templates for the design of new membrane-disruptive motifs. In particular the Cecropin-A and Melittin hybrids (CMs) are among the smallest and most effective peptides with membrane-perturbing abilities. Here we present a novel chimeric peptide in which the Tat(11) motif is fused to the CM(18) hybrid (KWKLFKKIGAVLKVLTTG, residues 1-7 of Cecropin-A and 2-12 of Melittin). When administered to cells, CM(18)-Tat(11) combines the two desired functionalities: efficient uptake and destabilization of endocytotic-vesicle membranes. We show that this chimeric peptide effectively increases cargo-molecule cytoplasm availability and allows the subsequent intracellular localization of diverse membrane-impermeable molecules (i.e. Tat(11)-EGFP fusion protein, calcein, dextrans, and plasmidic DNA) with no detectable cytotoxicity. The present results open the way to the rational engineering of "modular" cell-penetrating peptides (CPPs) that combine (i) efficient translocation from the extracellular milieu into vesicles and (ii) efficient release of molecules from vesicles into the cytoplasm. Copyright © 2012 Elsevier B.V. All rights reserved.

On the role of the second coding exon of the HIV-1 Tat protein in virus replication and MHC class I downregulation

NARCIS (Netherlands)

Verhoef, K.; Bauer, M.; Meyerhans, A.; Berkhout, B.

1998-01-01

Tat is an essential protein of human immunodeficiency virus type 1 (HIV-1) and activates transcription from the viral long terminal repeat (LTR) promoter. The tat gene is composed of two coding exons of which the first, corresponding to the N-terminal 72 amino acid residues, has been reported to be

Behavioral experience induces zif268 expression in mature granule cells but suppresses its expression in immature granule cells

Science.gov (United States)

Huckleberry, Kylie A.; Kane, Gary A.; Mathis, Rita J.; Cook, Sarah G.; Clutton, Jonathan E.; Drew, Michael R.

2015-01-01

Thousands of neurons are born each day in the dentate gyrus (DG), but many of these cells die before reaching maturity. Both death and survival of adult-born neurons are regulated by neuronal activity in the DG. The immediate-early gene (IEG) zif268 appears to be an important mediator of these effects, as its expression can be induced by neural activity and knockout of zif268 impairs survival of adult-born neurons (Richardson et al., 1992; Veyrac et al., 2013). Despite the apparent importance of zif268 for adult neurogenesis, its behavior-induced expression has not been fully characterized in adult-born neurons. Here we characterize behavior-evoked expression of zif268 in mature and newborn dentate granule cells (DGCs). We first quantified zif268 expression in doublecortin-positive (DCX+) immature neurons and in the general granule cell population after brief exposure to a novel environment (NE). In the general granule cell population, zif268 expression peaked 1 h after NE exposure and returned to baseline by 8 h post-exposure. However, in the DCX+ cells, zif268 expression was suppressed relative to home cage for at least 8 h post-exposure. We next asked whether suppression of zif268 in DCX+ immature cells occurs in other behavioral paradigms that recruit the hippocampus. Exposure to Morris water maze (MWM) training, an enriched environment, or a NE caused approximately equal suppression of zif268 expression in DCX+ cells and approximately equal activation of zif268 expression among the general granule cell population. The same behavioral procedures activated zif268 expression in 6-week-old BrdU-labeled adult-born neurons, indicating that zif268 suppression is specific to immature neurons. Finally, we asked whether zif268 suppression varied as a function of age within the DCX+ population, which ranges in age from 0 to approximately 4 weeks. NE exposure had no significant effect on zif268 expression in 2- or 4-week-old BrdU-labeled neurons, but it significantly

Tropomyosin Receptor Kinase A Expression on Merkel Cell Carcinoma Cells.

Science.gov (United States)

Wehkamp, Ulrike; Stern, Sophie; Krüger, Sandra; Hauschild, Axel; Röcken, Christoph; Egberts, Friederike

2017-11-01

Merkel cell carcinoma (MCC) is a malignant neuroendocrine skin tumor frequently associated with the Merkel cell polyomavirus. Immune checkpoint therapy showed remarkable results, although not all patients are responsive to this therapy. Anti-tropomyosin receptor kinase A (TrkA)-targeted treatment has shown promising results in several tumor entities. To determine TrkA expression in MCC as a rationale for potential targeted therapy. This case series study investigated the MCC specimens of 55 patients treated at the Department of Dermatology, University Hospital of Schleswig-Holstein, Kiel, Germany, from January 1, 2005, through December 31, 2015. Thirty-nine of the 55 samples were suitable for further histopathologic examination. Expression of TrkA was explored by immunohistochemical analysis. Diagnosis of MCC was confirmed by staining positive for cytokeratin 20 (CK20) and synaptophysin. Expression of TrkA on the tumor cells. Specimens of 39 patients (21 women and 18 men; mean [SD] age, 75.0 [7.8] years) underwent immunohistochemical investigation. Thirty-eight of 38 specimens expressed CK20 and synaptophysin on the MCC tumor cells (100% expression). Merkel cell polyomavirus was detected in 32 of 38 specimens (84%). Tropomyosin receptor kinase A was found in all 36 evaluable specimens on the tumor cells; 34 (94%) showed a weak and 2 (6%) showed a strong cytoplasmic expression. In addition, strongly positive perinuclear dots were observed in 30 of 36 specimens (83%). Tropomyosin receptor kinase A was expressed on MCC tumor cells in 100% of evaluable specimens. This result may lead to the exploration of new targeted treatment options in MCC, especially for patients who do not respond to anti-programmed cell death protein 1 treatment.

Determining Physical Mechanisms of Gene Expression Regulation from Single Cell Gene Expression Data

OpenAIRE

Ezer, Daphne; Moignard, Victoria; G?ttgens, Berthold; Adryan, Boris

2016-01-01

Many genes are expressed in bursts, which can contribute to cell-to-cell heterogeneity. It is now possible to measure this heterogeneity with high throughput single cell gene expression assays (single cell qPCR and RNA-seq). These experimental approaches generate gene expression distributions which can be used to estimate the kinetic parameters of gene expression bursting, namely the rate that genes turn on, the rate that genes turn off, and the rate of transcription. We construct a complete ...

Expression of stanniocalcin 1 in thyroid side population cells and thyroid cancer cells.

Science.gov (United States)

Hayase, Suguru; Sasaki, Yoshihito; Matsubara, Tsutomu; Seo, Daekwan; Miyakoshi, Masaaki; Murata, Tsubasa; Ozaki, Takashi; Kakudo, Kennichi; Kumamoto, Kensuke; Ylaya, Kris; Cheng, Sheue-yann; Thorgeirsson, Snorri S; Hewitt, Stephen M; Ward, Jerrold M; Kimura, Shioko

2015-04-01

Mouse thyroid side population (SP) cells consist of a minor population of mouse thyroid cells that may have multipotent thyroid stem cell characteristics. However the nature of thyroid SP cells remains elusive, particularly in relation to thyroid cancer. Stanniocalcin (STC) 1 and 2 are secreted glycoproteins known to regulate serum calcium and phosphate homeostasis. In recent years, the relationship of STC1/2 expression to cancer has been described in various tissues. Microarray analysis was carried out to determine genes up- and down-regulated in thyroid SP cells as compared with non-SP cells. Among genes up-regulated, stanniocalcin 1 (STC1) was chosen for study because of its expression in various thyroid cells by Western blotting and immunohistochemistry. Gene expression analysis revealed that genes known to be highly expressed in cancer cells and/or involved in cancer invasion/metastasis were markedly up-regulated in SP cells from both intact as well as partial thyroidectomized thyroids. Among these genes, expression of STC1 was found in five human thyroid carcinoma-derived cell lines as revealed by analysis of mRNA and protein, and its expression was inversely correlated with the differentiation status of the cells. Immunohistochemical analysis demonstrated higher expression of STC1 in the thyroid tumor cell line and thyroid tumor tissues from humans and mice. These results suggest that SP cells contain a population of cells that express genes also highly expressed in cancer cells including Stc1, which warrants further study on the role of SP cells and/or STC1 expression in thyroid cancer.

Exploring Transduction Mechanisms of Protein Transduction Domains (PTDs in Living Cells Utilizing Single-Quantum Dot Tracking (SQT Technology

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Yasuhiro Suzuki

2012-01-01

Full Text Available Specific protein domains known as protein transduction domains (PTDs can permeate cell membranes and deliver proteins or bioactive materials into living cells. Various approaches have been applied for improving their transduction efficacy. It is, therefore, crucial to clarify the entry mechanisms and to identify the rate-limiting steps. Because of technical limitations for imaging PTD behavior on cells with conventional fluorescent-dyes, how PTDs enter the cells has been a topic of much debate. Utilizing quantum dots (QDs, we recently tracked the behavior of PTD that was derived from HIV-1 Tat (TatP in living cells at the single-molecule level with 7-nm special precision. In this review article, we initially summarize the controversy on TatP entry mechanisms; thereafter, we will focus on our recent findings on single-TatP-QD tracking (SQT, to identify the major sequential steps of intracellular delivery in living cells and to discuss how SQT can easily provide direct information on TatP entry mechanisms. As a primer for SQT study, we also discuss the latest findings on single particle tracking of various molecules on the plasma membrane. Finally, we discuss the problems of QDs and the challenges for the future in utilizing currently available QD probes for SQT. In conclusion, direct identification of the rate-limiting steps of PTD entry with SQT should dramatically improve the methods for enhancing transduction efficiency.

Rho GTPase expression in human myeloid cells.

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Suzanne F G van Helden

Full Text Available Myeloid cells are critical for innate immunity and the initiation of adaptive immunity. Strict regulation of the adhesive and migratory behavior is essential for proper functioning of these cells. Rho GTPases are important regulators of adhesion and migration; however, it is unknown which Rho GTPases are expressed in different myeloid cells. Here, we use a qPCR-based approach to investigate Rho GTPase expression in myeloid cells.We found that the mRNAs encoding Cdc42, RhoQ, Rac1, Rac2, RhoA and RhoC are the most abundant. In addition, RhoG, RhoB, RhoF and RhoV are expressed at low levels or only in specific cell types. More differentiated cells along the monocyte-lineage display lower levels of Cdc42 and RhoV, while RhoC mRNA is more abundant. In addition, the Rho GTPase expression profile changes during dendritic cell maturation with Rac1 being upregulated and Rac2 downregulated. Finally, GM-CSF stimulation, during macrophage and osteoclast differentiation, leads to high expression of Rac2, while M-CSF induces high levels of RhoA, showing that these cytokines induce a distinct pattern. Our data uncover cell type specific modulation of the Rho GTPase expression profile in hematopoietic stem cells and in more differentiated cells of the myeloid lineage.

Forced Expression of ZNF143 Restrains Cancer Cell Growth

International Nuclear Information System (INIS)

Izumi, Hiroto; Yasuniwa, Yoshihiro; Akiyama, Masaki; Yamaguchi, Takahiro; Kuma, Akihiro; Kitamura, Noriaki; Kohno, Kimitoshi

2011-01-01

We previously reported that the transcription factor Zinc Finger Protein 143 (ZNF143) regulates the expression of genes associated with cell cycle and cell division, and that downregulation of ZNF143 induces cell cycle arrest at G2/M. To assess the function of ZNF143 expression in the cell cycle, we established two cells with forced expression of ZNF143 derived from PC3 prostate cancer cell lines. These cell lines overexpress genes associated with cell cycle and cell division, such as polo-like kinase 1 (PLK1), aurora kinase B (AURKB) and some minichromosome maintenance complex components (MCM). However, the doubling time of cells with forced expression of ZNF143 was approximately twice as long as its control counterpart cell line. Analysis following serum starvation and re-seeding showed that PC3 cells were synchronized at G1 in the cell cycle. Also, ZNF143 expression fluctuated, and was at its lowest level in G2/M. However, PC3 cells with forced expression of ZNF143 synchronized at G2/M, and showed lack of cell cycle-dependent fluctuation of nuclear expression of MCM proteins. Furthermore, G2/M population of both cisplatin-resistant PCDP6 cells over-expressing ZNF143 (derived from PC3 cells) and cells with forced expression of ZNF143 was significantly higher than that of each counterpart, and the doubling time of PCDP6 cells is about 2.5 times longer than that of PC3 cells. These data suggested that fluctuations in ZNF143 expression are required both for gene expression associated with cell cycle and for cell division

Forced Expression of ZNF143 Restrains Cancer Cell Growth

Energy Technology Data Exchange (ETDEWEB)

Izumi, Hiroto, E-mail: h-izumi@med.uoeh-u.ac.jp; Yasuniwa, Yoshihiro; Akiyama, Masaki; Yamaguchi, Takahiro; Kuma, Akihiro; Kitamura, Noriaki; Kohno, Kimitoshi [Department of Molecular Biology, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555 (Japan)

2011-10-19

We previously reported that the transcription factor Zinc Finger Protein 143 (ZNF143) regulates the expression of genes associated with cell cycle and cell division, and that downregulation of ZNF143 induces cell cycle arrest at G2/M. To assess the function of ZNF143 expression in the cell cycle, we established two cells with forced expression of ZNF143 derived from PC3 prostate cancer cell lines. These cell lines overexpress genes associated with cell cycle and cell division, such as polo-like kinase 1 (PLK1), aurora kinase B (AURKB) and some minichromosome maintenance complex components (MCM). However, the doubling time of cells with forced expression of ZNF143 was approximately twice as long as its control counterpart cell line. Analysis following serum starvation and re-seeding showed that PC3 cells were synchronized at G1 in the cell cycle. Also, ZNF143 expression fluctuated, and was at its lowest level in G2/M. However, PC3 cells with forced expression of ZNF143 synchronized at G2/M, and showed lack of cell cycle-dependent fluctuation of nuclear expression of MCM proteins. Furthermore, G2/M population of both cisplatin-resistant PCDP6 cells over-expressing ZNF143 (derived from PC3 cells) and cells with forced expression of ZNF143 was significantly higher than that of each counterpart, and the doubling time of PCDP6 cells is about 2.5 times longer than that of PC3 cells. These data suggested that fluctuations in ZNF143 expression are required both for gene expression associated with cell cycle and for cell division.

Forced Expression of ZNF143 Restrains Cancer Cell Growth

Directory of Open Access Journals (Sweden)

Kimitoshi Kohno

2011-10-01

Full Text Available We previously reported that the transcription factor Zinc Finger Protein 143 (ZNF143 regulates the expression of genes associated with cell cycle and cell division, and that downregulation of ZNF143 induces cell cycle arrest at G2/M. To assess the function of ZNF143 expression in the cell cycle, we established two cells with forced expression of ZNF143 derived from PC3 prostate cancer cell lines. These cell lines overexpress genes associated with cell cycle and cell division, such as polo-like kinase 1 (PLK1, aurora kinase B (AURKB and some minichromosome maintenance complex components (MCM. However, the doubling time of cells with forced expression of ZNF143 was approximately twice as long as its control counterpart cell line. Analysis following serum starvation and re-seeding showed that PC3 cells were synchronized at G1 in the cell cycle. Also, ZNF143 expression fluctuated, and was at its lowest level in G2/M. However, PC3 cells with forced expression of ZNF143 synchronized at G2/M, and showed lack of cell cycle-dependent fluctuation of nuclear expression of MCM proteins. Furthermore, G2/M population of both cisplatin-resistant PCDP6 cells over-expressing ZNF143 (derived from PC3 cells and cells with forced expression of ZNF143 was significantly higher than that of each counterpart, and the doubling time of PCDP6 cells is about 2.5 times longer than that of PC3 cells. These data suggested that fluctuations in ZNF143 expression are required both for gene expression associated with cell cycle and for cell division.

CD25+ B-1a Cells Express Aicda

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Hiroaki Kaku

2017-06-01

Full Text Available B-1a cells are innate-like B-lymphocytes producing natural antibodies. Activation-induced cytidine deaminase (AID, a product of the Aicda gene, plays a central role in class-switch recombination and somatic hypermutation in B cells. Although a role for Aicda in B-1a cells has been suggested on the basis of experiments with knock out (KO mice, whether B-1a cells express Aicda, and if so, which B-1a cell subpopulation expresses Aicda, remains unknown. Here, we demonstrate that B-1 cells express Aicda, but at a level below that expressed by germinal center (GC B cells. We previously reported that B-1a cells can be subdivided based on CD25 expression. We show here that B-1a cell Aicda expression is concentrated in the CD25+ B-1a cell subpopulation. These results suggest the possibility that previous studies of memory B cells identified on the basis of Aicda expression may have inadvertently included an unknown number of CD25+ B-1a cells. Although B-1a cells develop normally in the absence of Aicda, a competitive reconstitution assay reveals enhanced vigor for AID KO B-1a cell bone marrow (BM progenitors, as compared with wild-type BM B-1 cell progenitors. These results suggest that AID inhibits the development of B-1a cells from BM B-1 cell progenitors in a competitive environment.

Um caso de organização limite da personalidade: Um estudo comparativo da projeção no Rorschach e no TAT

OpenAIRE

Fernandez, Isabel Bernardo

1994-01-01

Apresenta-se um estudo comparativo dos protocolos do Rorschach e do TAT de uma jovem de quase 20 anos, diagnosticada como organização limite da personalidade, procurando mostrar como ambos se elucidam entre o Rorschach e o TAT.e completam num esclarecimento relativo aos «como» e

During development intense Sox2 expression marks not only Prox1-expressing taste bud cell but also perigemmal cell lineages.

Science.gov (United States)

Nakayama, Ayumi; Miura, Hirohito; Ooki, Makoto; Harada, Shuitsu

2015-03-01

Sox2 is proposed to regulate the differentiation of bipotential progenitor cells into taste bud cells. However, detailed expression of Sox2 remains unclear. In this report, Sox2 expression during taste bud development in the fungiform (FF), circumvallate (CV) and soft palate (SP) areas is examined together with Prox1. First, we immunohistochemically checked Prox1 expression in adults and found that almost all taste bud cells are Prox1-positive. During FF development, intense Sox2 expression was restricted to taste bud primordia expressing Prox1 at E12.5. However, at E14.5, Sox2 was intensely expressed outside the developing taste buds resolving to perigemmal Sox2 expression in adults. In the SP, at E14.5, taste bud primordia emerged as Prox1-expressing cell clusters. However, intense Sox2 expression was not restricted to taste bud primordia but was detected widely in the epithelium. During development, Sox2 expression outside developing taste buds was generally down-regulated but was retained in the perigemmal region similarly to that in the FF. In the CV, the initial stage of taste bud development remained unclear because of the lack of taste bud primordia comparable to that in the FF and SP. Here, we show that Prox1-expressing cells appear in the apical epithelium at E12.5, in the inner trench wall at E17.5 and in the outer trench wall at E18.5. Sox2 was again not restricted to developing taste bud cells expressing Prox1 during CV development. The expression patterns support that Sox2 does not serve as a cell fate selector between taste bud cells and surrounding keratinocytes but rather may contribute to them both.

Decorin expression in quiescent myogenic cells

International Nuclear Information System (INIS)

Nishimura, Takanori; Nozu, Kenjiro; Kishioka, Yasuhiro; Wakamatsu, Jun-ichi; Hattori, Akihito

2008-01-01

Satellite cells are quiescent muscle stem cells that promote postnatal muscle growth and repair. When satellite cells are activated by myotrauma, they proliferate, migrate, differentiate, and ultimately fuse to existing myofibers. The remainder of these cells do not differentiate, but instead return to quiescence and remain in a quiescent state until activation begins the process again. This ability to maintain their own population is important for skeletal muscle to maintain the capability to repair during postnatal life. However, the mechanisms by which satellite cells return to quiescence and maintain the quiescent state are still unclear. Here, we demonstrated that decorin mRNA expression was high in cell cultures containing a higher ratio of quiescent satellite cells when satellite cells were stimulated with various concentrations of hepatocyte growth factor. This result suggests that quiescent satellite cells express decorin at a high level compared to activated satellite cells. Furthermore, we examined the expression of decorin in reserve cells, which were undifferentiated myoblasts remaining after induction of differentiation by serum-deprivation. Decorin mRNA levels in reserve cells were higher than those in differentiated myotubes and growing myoblasts. These results suggest that decorin participates in the quiescence of myogenic cells

Maesopsin 4-O-beta-D-glucoside, a natural compound isolated from the leaves of Artocarpus tonkinensis, inhibits proliferation and up-regulates HMOX1, SRXN1 and BCAS3 in acute myeloid leukemia.

Science.gov (United States)

Pozzesi, N; Pierangeli, S; Vacca, C; Falchi, L; Pettorossi, V; Martelli, M P; Thuy, T T; Ninh, P T; Liberati, A M; Riccardi, C; Sung, T V; Delfino, D V

2011-06-01

The leaves of Artocarpus tonkinensis are used in Vietnamese traditional medicine for treatment of arthritis, and the compound maesopsin 4-O-β-D-glucoside (TAT-2), isolated from them, inhibits the proliferation of activated T cells. Our goal was to test the anti-proliferative activity of TAT-2 on the T-cell leukemia, Jurkat, and on the acute myeloid leukemia, OCI-AML. TAT-2 inhibited the growth of OCI-AML (and additional acute myeloid leukemia cells) but not Jurkat cells. Growth inhibition was shown to be due to inhibition of proliferation rather than increase in cell death. Analysis of cytokine release showed that TAT-2 stimulated the release of TGF-β, yet TGF-β neutralization did not reverse the maesopsin-dependent effect. Gene expression profiling determined that maesopsin modulated 19 identifiable genes. Transcription factor CP2 was the gene most significantly modulated. Real-time PCR validated that up-regulation of sulphiredoxin 1 homolog (SRXN1), hemeoxygenase 1 (HMOX1), and breast carcinoma amplified sequence 3 (BCAS3) were consistently modulated.

Effects of x-rays or aseptic inflammatory reaction on the circadian rythm of tyrosine aminotransferase in mouse liver (TAT activity of mouse liver)

International Nuclear Information System (INIS)

Jungowska-Klin, B.

1979-01-01

The circadian rhythm of tyrosine aminotransferase (TAT) was investigated during 48 hours in the liver of mice subjected to: a/ subcutaneous inflammatory reaction, b/ ionizing radiation. The cyclic changes in the circadian enzyme activity were described with a harmonic function. In relation to the control mice in the experimental mice statistically significant changes were demonstrated in the activity of tyrosine aminotransferase associated with desynchronization of the circadian TAT rhythm, particularly evident in the first hours of the first day of the experiment. The functions of enzyme activity changed in the second 24-hours period showed, both qualitatively and quantitatively, a tendency for a gradual return of normal TAT activity in the 24-hour periods. (author)

Haemopedia: An Expression Atlas of Murine Hematopoietic Cells

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Carolyn A. de Graaf

2016-09-01

Full Text Available Hematopoiesis is a multistage process involving the differentiation of stem and progenitor cells into distinct mature cell lineages. Here we present Haemopedia, an atlas of murine gene-expression data containing 54 hematopoietic cell types, covering all the mature lineages in hematopoiesis. We include rare cell populations such as eosinophils, mast cells, basophils, and megakaryocytes, and a broad collection of progenitor and stem cells. We show that lineage branching and maturation during hematopoiesis can be reconstructed using the expression patterns of small sets of genes. We also have identified genes with enriched expression in each of the mature blood cell lineages, many of which show conserved lineage-enriched expression in human hematopoiesis. We have created an online web portal called Haemosphere to make analyses of Haemopedia and other blood cell transcriptional datasets easier. This resource provides simple tools to interrogate gene-expression-based relationships between hematopoietic cell types and genes of interest.

Interactive HIV-1 Tat and morphine-induced synaptodendritic injury is triggered through focal disruptions in Na⁺ influx, mitochondrial instability, and Ca²⁺ overload.

Science.gov (United States)

Fitting, Sylvia; Knapp, Pamela E; Zou, Shiping; Marks, William D; Bowers, M Scott; Akbarali, Hamid I; Hauser, Kurt F

2014-09-17

Synaptodendritic injury is thought to underlie HIV-associated neurocognitive disorders and contributes to exaggerated inflammation and cognitive impairment seen in opioid abusers with HIV-1. To examine events triggering combined transactivator of transcription (Tat)- and morphine-induced synaptodendritic injury systematically, striatal neuron imaging studies were conducted in vitro. These studies demonstrated nearly identical pathologic increases in dendritic varicosities as seen in Tat transgenic mice in vivo. Tat caused significant focal increases in intracellular sodium ([Na(+)]i) and calcium ([Ca(2+)]i) in dendrites that were accompanied by the emergence of dendritic varicosities. These effects were largely, but not entirely, attenuated by the NMDA and AMPA receptor antagonists MK-801 and CNQX, respectively. Concurrent morphine treatment accelerated Tat-induced focal varicosities, which were accompanied by localized increases in [Ca(2+)]i and exaggerated instability in mitochondrial inner membrane potential. Importantly, morphine's effects were prevented by the μ-opioid receptor antagonist CTAP and were not observed in neurons cultured from μ-opioid receptor knock-out mice. Combined Tat- and morphine-induced initial losses in ion homeostasis and increases in [Ca(2+)]i were attenuated by the ryanodine receptor inhibitor ryanodine, as well as pyruvate. In summary, Tat induced increases in [Na(+)]i, mitochondrial instability, excessive Ca(2+) influx through glutamatergic receptors, and swelling along dendrites. Morphine, acting via μ-opioid receptors, exacerbates these excitotoxic Tat effects at the same subcellular locations by mobilizing additional [Ca(2+)]i and by further disrupting [Ca(2+)]i homeostasis. We hypothesize that the spatiotemporal relationship of μ-opioid and aberrant AMPA/NMDA glutamate receptor signaling is critical in defining the location and degree to which opiates exacerbate the synaptodendritic injury commonly observed in neuro

Temporal anomaly detection: an artificial immune approach based on T cell activation, clonal size regulation and homeostasis.

Science.gov (United States)

Antunes, Mário J; Correia, Manuel E

2010-01-01

This paper presents an artificial immune system (AIS) based on Grossman's tunable activation threshold (TAT) for temporal anomaly detection. We describe the generic AIS framework and the TAT model adopted for simulating T Cells behaviour, emphasizing two novel important features: the temporal dynamic adjustment of T Cells clonal size and its associated homeostasis mechanism. We also present some promising results obtained with artificially generated data sets, aiming to test the appropriateness of using TAT in dynamic changing environments, to distinguish new unseen patterns as part of what should be detected as normal or as anomalous. We conclude by discussing results obtained thus far with artificially generated data sets.

Foxp3 expression in human cancer cells

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Gourgoulianis Konstantinos I

2008-04-01

Full Text Available Abstract Objective Transcription factor forkhead box protein 3 (Foxp3 specifically characterizes the thymically derived naturally occurring regulatory T cells (Tregs. Limited evidence indicates that it is also expressed, albeit to a lesser extent, in tissues other than thymus and spleen, while, very recently, it was shown that Foxp3 is expressed by pancreatic carcinoma. This study was scheduled to investigate whether expression of Foxp3 transcripts and mature protein occurs constitutively in various tumor types. Materials and methods Twenty five tumor cell lines of different tissue origins (lung cancer, colon cancer, breast cancer, melanoma, erythroid leukemia, acute T-cell leukemia were studied. Detection of Foxp3 mRNA was performed using both conventional RT-PCR and quantitative real-time PCR while protein expression was assessed by immunocytochemistry and flow cytometry, using different antibody clones. Results Foxp3 mRNA as well as Foxp3 protein was detected in all tumor cell lines, albeit in variable levels, not related to the tissue of origin. This expression correlated with the expression levels of IL-10 and TGFb1. Conclusion We offer evidence that Foxp3 expression, characterizes tumor cells of various tissue origins. The biological significance of these findings warrants further investigation in the context of tumor immune escape, and especially under the light of current anti-cancer efforts interfering with Foxp3 expression.

Les réserves extractivistes, état des lieux

OpenAIRE

Aubertin, Catherine

2014-01-01

La lutte des seringueiros a popularisé la notion de réserves extractivistes. Au départ calquée sur le modèle de la réserve indigène, la réserve extractiviste devait apporter une solution foncière aux conflits avec les patrons en garantissant, grâce à des expropriations menées par l’État, un droit d’usage collectif aux seringueiros et le maintien de leur outil de production, la forêt. L’histoire des réserves extractivistes est significative des modifications politiques enregistrées ces dix der...

Feline immunodeficiency virus OrfA alters gene expression of splicing factors and proteasome-ubiquitination proteins

International Nuclear Information System (INIS)

Sundstrom, Magnus; Chatterji, Udayan; Schaffer, Lana; Rozieres, Sohela de; Elder, John H.

2008-01-01

Expression of the feline immunodeficiency virus (FIV) accessory protein OrfA (or Orf2) is critical for efficient viral replication in lymphocytes, both in vitro and in vivo. OrfA has been reported to exhibit functions in common with the human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) accessory proteins Vpr and Tat, although the function of OrfA has not been fully explained. Here, we use microarray analysis to characterize how OrfA modulates the gene expression profile of T-lymphocytes. The primary IL-2-dependent T-cell line 104-C1 was transduced to express OrfA. Functional expression of OrfA was demonstrated by trans complementation of the OrfA-defective clone, FIV-34TF10. OrfA-expressing cells had a slightly reduced cell proliferation rate but did not exhibit any significant alteration in cell cycle distribution. Reverse-transcribed RNA from cells expressing green fluorescent protein (GFP) or GFP + OrfA were hybridized to Affymetrix HU133 Plus 2.0 microarray chips representing more than 47,000 genome-wide transcripts. By using two statistical approaches, 461 (Rank Products) and 277 (ANOVA) genes were identified as modulated by OrfA expression. The functional relevance of the differentially expressed genes was explored by Ingenuity Pathway Analysis. The analyses revealed alterations in genes critical for RNA post-transcriptional modifications and protein ubiquitination as the two most significant functional outcomes of OrfA expression. In these two groups, several subunits of the spliceosome, cellular splicing factors and family members of the proteasome-ubiquitination system were identified. These findings provide novel information on the versatile function of OrfA during FIV infection and indicate a fine-tuning mechanism of the cellular environment by OrfA to facilitate efficient FIV replication

CPP2-p16MIS treatment–induced colon carcinoma cell death in vitro and prolonged lifespan of tumor-bearing mice

International Nuclear Information System (INIS)

Wang, Lifeng; Chen, Haijin; Yu, Jinlong; Lin, Xiaohua; Qi, Jia; Cui, Chunhui; Xie, Lang; Huang, Shuxin

2016-01-01

Cell-penetrating peptides (CPPs) are a research hotspot due to their noninvasive delivery ability. Among the identified CPPs, the TAT and R8 peptides have been preferentially applied to transduction into different cells. However, this process is nonselective among various cells. Recent research suggested that CPP2 could selectively penetrate human colorectal cancer (CRC) cells. Using in vitro experiments, the mean fluorescence intensity of fluorescein isothiocyanate–labeled CPPs (CPPs-FITC) incubated with different cell lines was compared to corroborate the colon tumor targeting ability of CPP2. The targeting ability of CPP2 was determined in the same way in tumor-bearing mice. We synthesized antitumor peptides by fusing CPP2 to the minimal inhibitory sequence of p16 (p16MIS), which had the ability to restore the function of lost p16, the expression of which was absent in tumor cell lines of various origins. The antitumor effect of the combined peptide was tested in both CRC cell lines and tumor-bearing mice. In each CRC cell line, the mean fluorescence intensity of CPP2-FITC was higher than that of the TAT-FITC (p < 0.001) and R8-FITC (p < 0.001) groups. CPP2-p16MIS, the targeting carrier, showed a higher antitumor response in the in vitro cell research. CPP2-p16MIS showed a prolonged mean lifespan of tumor-bearing mice, further characterizing its role in specific tumor-targeting ability in vivo. Survival analysis showed that the mice treated with CPP2-p16MIS had significantly longer survival than the mice treated with phosphate-buffered saline (p < 0.05) or those treated with control peptides, including the CPP2 (p < 0.05) and p16MIS (p < 0.05) groups. CPP2 could more selectively penetrate CRC cells than TAT or R8 as well as effectively deliver the p16MIS to the tumor

Induction of a robust immune response against avian influenza virus following transdermal inoculation with H5-DNA vaccine formulated in modified dendrimer-based delivery system in mouse model.

Science.gov (United States)

Bahadoran, Azadeh; Ebrahimi, Mehdi; Yeap, Swee Keong; Safi, Nikoo; Moeini, Hassan; Hair-Bejo, Mohd; Hussein, Mohd Zobir; Omar, Abdul Rahman

2017-01-01

This study was aimed to evaluate the immunogenicity of recombinant plasmid deoxyribonucleic acid (DNA), pBud-H5-green fluorescent protein (GFP)-interferon-regulatory factor (IRF)3 following delivery using polyamidoamine (PAMAM) dendrimer and transactivator of transcription (TAT)-conjugated PAMAM dendrimer as well as the effect of IRF3 as the genetic adjuvant. BALB/c mice were vaccinated transdermally with pBud-H5-GFP, PAMAM/pBud-H5-GFP, TAT-PAMAM/pBud-H5-GFP, and TAT-PAMAM/pBud-H5-GFP-IRF3. The expression analysis of H5 gene from the blood by using quantitative real-time reverse transcriptase polymerase chain reaction confirmed the ability of PAMAM dendrimer as a carrier for gene delivery, as well as the ability of TAT peptide to enhance the delivery efficiency of PAMAM dendrimer. Mice immunized with modified PAMAM by TAT peptide showed higher hemagglutination inhibition titer, and larger CD3 + /CD4 + T cells and CD3 + /CD8 + T cells population, as well as the production of cytokines, namely, interferon (IFN)-γ, interleukin (IL)-2, IL-15, IL-12, IL-6, and tumor necrosis factor-α compared with those immunized with native PAMAM. These results suggest that the function of TAT peptide as a cell-penetrating peptide is able to enhance the gene delivery, which results in rapid distribution of H5 in the tissues of the immunized mice. Furthermore, pBud-H5-GFP co-expressing IRF3 as a genetic adjuvant demonstrated the highest hemagglutination inhibition titer besides larger CD3 + /CD4 + and CD3 + /CD8 + T cells population, and strong Th1-like cytokine responses among all the systems tested. In conclusion, TAT-PAMAM dendrimer-based delivery system with IRF3 as a genetic adjuvant is an attractive transdermal DNA vaccine delivery system utilized to evaluate the efficacy of the developed DNA vaccine in inducing protection during challenge with virulent H5N1 virus.

Non-Small Cell Lung Cancer Cells Expressing CD44 Are Enriched for Stem Cell-Like Properties

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Leung, Elaine Lai-Han; Fiscus, Ronald R.; Tung, James W.; Tin, Vicky Pui-Chi; Cheng, Lik Cheung; Sihoe, Alan Dart-Loon; Fink, Louis M.; Ma, Yupo; Wong, Maria Pik

2010-01-01

Background The cancer stem cell theory hypothesizes that cancers are perpetuated by cancer stem cells (CSC) or tumor initiating cells (TIC) possessing self-renewal and other stem cell-like properties while differentiated non-stem/initiating cells have a finite life span. To investigate whether the hypothesis is applicable to lung cancer, identification of lung CSC and demonstration of these capacities is essential. Methodology/Principal Finding The expression profiles of five stem cell markers (CD34, CD44, CD133, BMI1 and OCT4) were screened by flow cytometry in 10 lung cancer cell lines. CD44 was further investigated by testing for in vitro and in vivo tumorigenecity. Formation of spheroid bodies and in vivo tumor initiation ability were demonstrated in CD44+ cells of 4 cell lines. Serial in vivo tumor transplantability in nude mice was demonstrated using H1299 cell line. The primary xenografts initiated from CD44+ cells consisted of mixed CD44+ and CD44− cells in similar ratio as the parental H1299 cell line, supporting in vivo differentiation. Semi-quantitative Real-Time PCR (RT-PCR) showed that both freshly sorted CD44+ and CD44+ cells derived from CD44+-initiated tumors expressed the pluripotency genes OCT4/POU5F1, NANOG, SOX2. These stemness markers were not expressed by CD44− cells. Furthermore, freshly sorted CD44+ cells were more resistant to cisplatin treatment with lower apoptosis levels than CD44− cells. Immunohistochemical analysis of 141 resected non-small cell lung cancers showed tumor cell expression of CD44 in 50.4% of tumors while no CD34, and CD133 expression was observed in tumor cells. CD44 expression was associated with squamous cell carcinoma but unexpectedly, a longer survival was observed in CD44-expressing adenocarcinomas. Conclusion/Significance Overall, our results demonstrated that stem cell-like properties are enriched in CD44-expressing subpopulations of some lung cancer cell lines. Further investigation is required to clarify

La digestion anaérobie des boues de stations d'épuration urbaines :état des lieux - état de l'art

OpenAIRE

Reverdy, A.L; Baudez, J.C.; Dieudé-Fauvel, E.

2011-01-01

/ Avec le protocole de Kyoto et le Grenelle de l'environnement, les politiques actuelles prônent le développement des énergies renouvelables. La digestion anaérobie des boues de stations d'épuration urbaines est un procédé permettant de répondre à cette exigence. L'étude présentée dans ce rapport offre dans un premier temps un descriptif du procédé de méthanisation. Dans une deuxième partie, un état des lieux de la digestion anaérobie des boues d'épuration urbaines est réalisé en France...

Thermodynamic studies of a series of homologous HIV-1 TAR RNA ligands reveal that loose binders are stronger Tat competitors than tight ones.

Science.gov (United States)

Pascale, Lise; Azoulay, Stéphane; Di Giorgio, Audrey; Zenacker, Laura; Gaysinski, Marc; Clayette, Pascal; Patino, Nadia

2013-06-01

RNA is a major drug target, but the design of small molecules that modulate RNA function remains a great challenge. In this context, a series of structurally homologous 'polyamide amino acids' (PAA) was studied as HIV-1 trans-activating response (TAR) RNA ligands. An extensive thermodynamic study revealed the occurence of an enthalpy-entropy compensation phenomenon resulting in very close TAR affinities for all PAA. However, their binding modes and their ability to compete with the Tat fragment strongly differ according to their structure. Surprisingly, PAA that form loose complexes with TAR were shown to be stronger Tat competitors than those forming tight ones, and thermal denaturation studies demonstrated that loose complexes are more stable than tight ones. This could be correlated to the fact that loose and tight ligands induce distinct RNA conformational changes as revealed by circular dichroism experiments, although nuclear magnetic resonance (NMR) experiments showed that the TAR binding site is the same in all cases. Finally, some loose PAA also display promising inhibitory activities on HIV-infected cells. Altogether, these results lead to a better understanding of RNA interaction modes that could be very useful for devising new ligands of relevant RNA targets.

Optimization of expression JTAT protein with emphasis on transformation efficiency and IPTG concentration

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Endang Tri Margawati

2017-12-01

Full Text Available One of small accessory genes between pol and env is tat gene encoding TAT protein. This research was aimed to optimize the expression of Jembrana TAT (JTAT protein with preparing Escherichia coli (E. coli in advance using adopted methods of M1 (MgCl2 + CaCl2 and M2 (CaCl2 + Glycerol. The best transformation efficiency resulting from a better transformation method was used to subsequent expression of JTAT protein. A synthetic tat gene encoding protein JTAT was previously cloned into pBT-hisC. Concentration of 200; 400; 600 µM IPTG was induced to a small volume culture (200 ml; OD600 = 4, incubated for 3 h. Pellets were harvested by centrifugation (4000 rpm; 4 °C; 15 min. Buffer B (10 mM Immidazole was added into pellets, lysed by freeze-thaw followed by sonication. Supernatant was collected by centrifugation (10,000 rpm; 4 °C; 20 min and purified using Ni-NTA Agarose resin, released by elution buffer (E containing 400 mM Immidazole to collect purified protein twice (E1, E2. The protein was characterized by SDS-PAGE and Western Blot (WB, quantified (at λ595 nm with BSA standard method in prior. The result showed that transformation efficiency was better in M2 (2.53 × 106 than M1 (3.10 × 105. The JTAT protein was expressed at a right size of 11.8 kDa. Concentration of 200 µM IPTG produced a significantly better protein yield (1.500 ± 0.089 mg/ml; P < 0.05 than 600 µM IPTG (0.896 ± 0.052 mg/ml and not different to 400 µM IPTG (1.298 ± 0.080 mg/ml. This research indicated that transformation efficiency needs to be taken account in prior of optimization of the protein expression.

La gouvernance de la sécurité dans les États faibles et défaillants The Governance of Security in Weak and Failing State

OpenAIRE

Samuel Tanner; Benoît Dupont; Peter Grabosky; Clifford Shearing

2009-01-01

Cet article vise à identifier des moyens permettant le renforcement des mécanismes de contrôle social et de résolution des conflits dans les États faibles et défaillants. Après avoir examiné la gouvernance de la sécurité telle qu’elle se développe dans les États forts, nous montrons que certaines configurations institutionnelles peuvent être transposées dans un contexte d’État faible, où les institutions étatiques en charge de la sécurité sont défaillantes ou inexistantes. Nous identifions de...

CNPase Expression in Olfactory Ensheathing Cells

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Christine Radtke

2011-01-01

Full Text Available A large body of work supports the proposal that transplantation of olfactory ensheathing cells (OECs into nerve or spinal cord injuries can promote axonal regeneration and remyelination. Yet, some investigators have questioned whether the transplanted OECs associate with axons and form peripheral myelin, or if they recruit endogenous Schwann cells that form myelin. Olfactory bulbs from transgenic mice expressing the enhanced green fluorescent protein (eGFP under the control of the 2-3-cyclic nucleotide 3-phosphodiesterase (CNPase promoter were studied. CNPase is expressed in myelin-forming cells throughout their lineage. We examined CNPase expression in both in situ in the olfactory bulb and in vitro to determine if OECs express CNPase commensurate with their myelination potential. eGFP was observed in the outer nerve layer of the olfactory bulb. Dissociated OECs maintained in culture had both intense eGFP expression and CNPase immunostaining. Transplantation of OECs into transected peripheral nerve longitudinally associated with the regenerated axons. These data indicate that OECs in the outer nerve layer of the olfactory bulb of CNPase transgenic mice express CNPase. Thus, while OECs do not normally form myelin on olfactory nerve axons, their expression of CNPase is commensurate with their potential to form myelin when transplanted into injured peripheral nerve.

Foxl1-Expressing Mesenchymal Cells Constitute the Intestinal Stem Cell NicheSummary

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Reina Aoki

2016-03-01

Full Text Available Background & Aims: Intestinal epithelial stem cells that express leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5 and/or B cell specific Moloney murine leukemia virus integration site 1 (Bmi1 continuously replicate and generate differentiated cells throughout life. Previously, Paneth cells were suggested to constitute an epithelium-intrinsic niche that regulates the behavior of these stem cells. However, ablating Paneth cells has no effect on the maintenance of functional stem cells. Here, we show definitively that a small subset of mesenchymal subepithelial cells expressing the winged-helix transcription factor forkhead box l1 (Foxl1 are a critical component of the intestinal stem cell niche. Methods: We genetically ablated Foxl1+ mesenchymal cells in adult mice using 2 separate models by expressing either the human or simian diphtheria toxin receptor under Foxl1 promoter control. Conclusions: Killing Foxl1+ cells by diphtheria toxin administration led to an abrupt cessation of proliferation of both epithelial stem- and transit-amplifying progenitor cell populations that was associated with a loss of active Wnt signaling to the intestinal epithelium. Therefore, Foxl1-expressing mesenchymal cells constitute the fundamental niche for intestinal stem cells. Keywords: Intestinal Stem Cell Niche, Wnt, Mesenchyme

Rethinking cell-cycle-dependent gene expression in Schizosaccharomyces pombe.

Science.gov (United States)

Cooper, Stephen

2017-11-01

Three studies of gene expression during the division cycle of Schizosaccharomyces pombe led to the proposal that a large number of genes are expressed at particular times during the S. pombe cell cycle. Yet only a small fraction of genes proposed to be expressed in a cell-cycle-dependent manner are reproducible in all three published studies. In addition to reproducibility problems, questions about expression amplitudes, cell-cycle timing of expression, synchronization artifacts, and the problem with methods for synchronizing cells must be considered. These problems and complications prompt the idea that caution should be used before accepting the conclusion that there are a large number of genes expressed in a cell-cycle-dependent manner in S. pombe.

Glutathione S-transferase expression and isoenzyme composition during cell differentiation of Caco-2 cells

International Nuclear Information System (INIS)

Scharmach, E.; Hessel, S.; Niemann, B.; Lampen, A.

2009-01-01

The human colon adenocarcinoma cell line Caco-2 is frequently used to study human intestinal metabolism and transport of xenobiotica. Previous studies have shown that both Caco-2 cells and human colon cells constitutively express the multigene family of detoxifying enzymes glutathione S-transferases (GSTs), particularly GST alpha and GST pi. GSTs may play a fundamental role in the molecular interplay between phase I, II enzymes and ABC-transporters. The gut fermentation product, butyrate, can modulate the potential for detoxification. The aim of this study was to investigate the basal expression of further cytosolic GSTs in Caco-2 cells during cell differentiation. In addition, a comparison was made with expression levels in MCF-7 and HepG2, two other cell types with barrier functions. Finally, the butyrate-mediated modulation of gene and protein expression was determined by real time PCR and western blot analysis. In Caco-2, gene and protein expression levels of GST alpha increased during cell differentiation. High levels of GSTO1 and GSTP1 were constantly expressed. No expression of GSTM5 and GSTT1 was detected. HepG2 expressed GSTO1 and MCF-7 GSTZ1 most intensively. No expression of GSTA5, GSTM5, or GSTP1 was detected in either cell. Incubation of Caco-2 cells with butyrate (5 mM) significantly induced GSTA1 and GSTM2 in proliferating Caco-2 cells. In differentiated cells, butyrate tended to increase GSTO1 and GSTP1. The results of this study show that a differentiation-dependent expression of GSTs in Caco-2 cells may reflect the in vivo situation and indicate the potential of butyrate to modify intestinal metabolism. GSTA1-A4 have been identified as good markers for cell differentiation. The Caco-2 cell line is a useful model for assessing the potential of food-related substances to modulate the GST expression pattern.

Glutathione S-transferase expression and isoenzyme composition during cell differentiation of Caco-2 cells.

Science.gov (United States)

Scharmach, E; Hessel, S; Niemann, B; Lampen, A

2009-11-30

The human colon adenocarcinoma cell line Caco-2 is frequently used to study human intestinal metabolism and transport of xenobiotica. Previous studies have shown that both Caco-2 cells and human colon cells constitutively express the multigene family of detoxifying enzymes glutathione S-transferases (GSTs), particularly GST alpha and GST pi. GSTs may play a fundamental role in the molecular interplay between phase I, II enzymes and ABC-transporters. The gut fermentation product, butyrate, can modulate the potential for detoxification. The aim of this study was to investigate the basal expression of further cytosolic GSTs in Caco-2 cells during cell differentiation. In addition, a comparison was made with expression levels in MCF-7 and HepG2, two other cell types with barrier functions. Finally, the butyrate-mediated modulation of gene and protein expression was determined by real time PCR and western blot analysis. In Caco-2, gene and protein expression levels of GST alpha increased during cell differentiation. High levels of GSTO1 and GSTP1 were constantly expressed. No expression of GSTM5 and GSTT1 was detected. HepG2 expressed GSTO1 and MCF-7 GSTZ1 most intensively. No expression of GSTA5, GSTM5, or GSTP1 was detected in either cell. Incubation of Caco-2 cells with butyrate (5 mM) significantly induced GSTA1 and GSTM2 in proliferating Caco-2 cells. In differentiated cells, butyrate tended to increase GSTO1 and GSTP1. The results of this study show that a differentiation-dependent expression of GSTs in Caco-2 cells may reflect the in vivo situation and indicate the potential of butyrate to modify intestinal metabolism. GSTA1-A4 have been identified as good markers for cell differentiation. The Caco-2 cell line is a useful model for assessing the potential of food-related substances to modulate the GST expression pattern.

Oncomirs Expression Profiling in Uterine Leiomyosarcoma Cells

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Bruna Cristine de Almeida

2017-12-01

Full Text Available MicroRNAs (miRNAs are small non-coding RNAs that act as regulators of gene expression at the post-transcriptional level. They play a key role in several biological processes. Their abnormal expression may lead to malignant cell transformation. This study aimed to evaluate the expression profile of 84 miRNAs involved in tumorigenesis in immortalized cells of myometrium (MM, uterine leiomyoma (ULM, and uterine leiomyosarcoma (ULMS. Specific cell lines were cultured and qRT-PCR was performed. Thirteen miRNAs presented different expression profiles in ULM and the same thirteen in ULMS compared to MM. Eight miRNAs were overexpressed, and five were underexpressed in ULM. In ULMS cells, five miRNAs exhibited an overexpression and eight were down-regulated. Six miRNAs (miR-1-3p, miR-130b-3p, miR-140-5p, miR-202-3p, miR-205-5p, and miR-7-5p presented a similar expression pattern in cell lines compared to patient samples. Of these, only three miRNAs showed significant expression in ULM (miR-1-3p, miR-140-5p, and miR-7-5p and ULMS (miR-1-3p, miR-202-3p, and miR-7-5p. Our preliminary approach identified 24 oncomirs with an altered expression profile in ULM and ULMS cells. We identified four differentially expressed miRNAs with the same profile when compared with patients’ samples, which strongly interacted with relevant genes, including apoptosis regulator (BCL2, epidermal growth factor receptor (EGFR, vascular endothelial growth factor A (VEGFA, insulin like growth factor 1 receptor (IGF1R,serine/threonine kinase (RAF1, receptor tyrosine kinase (MET, and bHLH transcription factor (MYCN. This led to alterations in their mRNA-target.

The Politics of Religion in the United States Manifestations politiques de la religion aux États-Unis

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Josef Braml

2011-04-01

Full Text Available Aux États-Unis, les attitudes religieuses ont plus d’influence sur les choix politiques que dans n’importe quelle autre démocratie occidentale. L’engagement religieux/moral de la droite chrétienne polarise les États-Unis, ce qui a des conséquences sur le plan électoral mais aussi sur les choix politiques réels. L’importance de la droite chrétienne dans la coalition électorale du Parti républicain oblige celui-ci à mettre l’accent sur les questions liées à la sécurité nationale, en particulier la lutte anti-terroriste, afin de mieux souder une coalition électorale hétérogène.

Automatic Control of Gene Expression in Mammalian Cells.

Science.gov (United States)

Fracassi, Chiara; Postiglione, Lorena; Fiore, Gianfranco; di Bernardo, Diego

2016-04-15

Automatic control of gene expression in living cells is paramount importance to characterize both endogenous gene regulatory networks and synthetic circuits. In addition, such a technology can be used to maintain the expression of synthetic circuit components in an optimal range in order to ensure reliable performance. Here we present a microfluidics-based method to automatically control gene expression from the tetracycline-inducible promoter in mammalian cells in real time. Our approach is based on the negative-feedback control engineering paradigm. We validated our method in a monoclonal population of cells constitutively expressing a fluorescent reporter protein (d2EYFP) downstream of a minimal CMV promoter with seven tet-responsive operator motifs (CMV-TET). These cells also constitutively express the tetracycline transactivator protein (tTA). In cells grown in standard growth medium, tTA is able to bind the CMV-TET promoter, causing d2EYFP to be maximally expressed. Upon addition of tetracycline to the culture medium, tTA detaches from the CMV-TET promoter, thus preventing d2EYFP expression. We tested two different model-independent control algorithms (relay and proportional-integral (PI)) to force a monoclonal population of cells to express an intermediate level of d2EYFP equal to 50% of its maximum expression level for up to 3500 min. The control input is either tetracycline-rich or standard growth medium. We demonstrated that both the relay and PI controllers can regulate gene expression at the desired level, despite oscillations (dampened in the case of the PI controller) around the chosen set point.

Expression of MIF and CD74 in leukemic cell lines: correlation to DR expression destiny.

Science.gov (United States)

Georgouli, Mirella; Papadimitriou, Lina; Glymenaki, Maria; Patsaki, Valia; Athanassakis, Irene

2016-06-01

Invariant chain (Ii) or CD74 is a non-polymorphic glycoprotein, which apart from its role as a chaperone dedicated to MHCII molecules, is known to be a high-affinity receptor for macrophage migration inhibitory factor (MIF). The present study aimed to define the roles of CD74 and MIF in the immune surveillance escape process. Towards this direction, the cell lines HL-60, Raji, K562 and primary pre-B leukemic cells were examined for expression and secretion of MIF. Flow cytometry analysis detected high levels of MIF and intracellular/membrane CD74 expression in all leukemic cells tested, while MIF secretion was shown to be inversely proportional to intracellular HLA-DR (DR) expression. In the MHCII-negative cells, IFN-γ increased MIF expression and induced its secretion in HL-60 and K562 cells, respectively. In K562 cells, CD74 (Iip33Iip35) was shown to co-precipitate with HLA-DOβ (DOβ), inhibiting thus MIF or DR binding. Induced expression of DOα in K562 (DOα-DOβ+) cells in different transfection combinations decreased MIF expression and secretion, while increasing surface DR expression. Thus, MIF could indeed be part of the antigen presentation process.

Impaired cell surface expression of HLA-B antigens on mesenchymal stem cells and muscle cell progenitors

DEFF Research Database (Denmark)

Isa, Adiba; Nehlin, Jan; Sabir, Hardee Jawad

2010-01-01

HLA class-I expression is weak in embryonic stem cells but increases rapidly during lineage progression. It is unknown whether all three classical HLA class-I antigens follow the same developmental program. In the present study, we investigated allele-specific expression of HLA-A, -B, and -C...... at the mRNA and protein levels on human mesenchymal stem cells from bone marrow and adipose tissue as well as striated muscle satellite cells and lymphocytes. Using multicolour flow cytometry, we found high cell surface expression of HLA-A on all stem cells and PBMC examined. Surprisingly, HLA-B was either...... undetectable or very weakly expressed on all stem cells protecting them from complement-dependent cytotoxicity (CDC) using relevant human anti-B and anti-Cw sera. IFNgamma stimulation for 48-72 h was required to induce full HLA-B protein expression. Quantitative real-time RT-PCR showed that IFNgamma induced...

CD40 expression in Wehi-164 cell line.

Science.gov (United States)

Karimi, Mohammad Hossein; Ebadi, Padideh; Pourfathollah, Ali Akbar; Soheili, Zahra Soheila; Moazzeni, Seyed Mohammad

2010-07-01

CD40-CD154 interaction is an important process for cellular and humoral immunity regulation and can be effective in the body's defense against tumors. In the present study, we evaluated the expression of CD40 in Wehi-164 cell line. CD40 expressions on the cell surface and in the cytoplasm were assessed by flow cytometry and intracellular staining assay, respectively. Also, the mRNA expression was identified by real time-PCR. The obtained results showed the high mRNA and cytoplasmic protein expression of CD40 but no surface expression. These results suggest that the Wehi-164 cell line down regulates expression of CD40 on the surface for evasion of immune system.

HBx induced AFP receptor expressed to activate PI3K/AKT signal to promote expression of Src in liver cells and hepatoma cells

International Nuclear Information System (INIS)

Zhu, Mingyue; Guo, Junli; Li, Wei; Xia, Hua; Lu, Yan; Dong, Xu; Chen, Yi; Xie, Xieju; Fu, Shigan; Li, Mengsen

2015-01-01

Hepatitis B virus (HBV)-X protein(HBx) is a transactivator of host several cellular genes including alpha-fetoprotein(AFP) and AFP receptor(AFPR) which contributes to HBV-associated tumor development. The expression of AFP/AFPR are correlated with hepatocellular carcinoma(HCC)-initial cells. But the role of AFP and AFPR in promoting occurrence of HBV-related HCC were still unclear. A total of 71 clinical patients’ liver specimens, normal human liver cells L-02 and HCC cell lines, PLC/PRF/5 were selected for analyzing the effects of HBx on expression of AFP, AFPR and Src. The expression of goal proteins were detected by Immunohistochemical stained and Western blotting; HBx-expressed vectors were constructed and transfected into L-02 cells, laser confocal microscopy was applied to observe expression and location of AFP, AFPR and Src in the normal liver cells and HCC cells, soft agar colony formation assay was used to observe colonies formed of the cells. We confirmed HBx gives preference to promote the expression of AFP and AFPR; HBx priors to up-regulate the expression of AFPR and AFP in L-02 cells and in normal liver specimens; AFPR signal been able to stimulate Src expression. The results also indicated that phosphatidylinositol 3-kinase(PI3K) inhibitors Ly294002 and GDC0941 effectively suppress AFPR mediated up-regulation expression of Src in AFPR positive HCC lines. HBx priors to drive the expression of AFP and AFPR to promote expression of Src in normal liver cells and hepatoma cells; AFP and AFPR maybe play pivotal role in HBV-related hepatocarcinogenesis; Targeting AFPR is an available therapeutic strategy of HCC. The online version of this article (doi:10.1186/s12885-015-1384-9) contains supplementary material, which is available to authorized users

Expression of myc family oncoproteins in small-cell lung-cancer cell lines and xenografts

DEFF Research Database (Denmark)

Rygaard, K; Vindeløv, L L; Spang-Thomsen, M

1993-01-01

A number of genes have altered activity in small-cell lung cancer (SCLC), but especially genes of the myc family (c-myc, L-myc and N-myc) are expressed at high levels in SCLC. Most studies have explored expression at the mRNA level, whereas studies of myc family oncoprotein expression are sparse....... WE examined the expression of myc proto-oncogenes at the mRNA and protein level in 23 cell lines or xenografts. In the cell lines, the doubling time and the cell-cycle distribution, as determined by flow-cytometric DNA analysis, were examined to establish whether the level of myc......-myc. In general, the level of expression of c-myc and N-myc was similar at the mRNA and the protein level. Expression of c-myc was positively correlated with the proliferative index (sum of S and G2+M phases) of cell lines, but not with the population doubling time. In general, L-myc-expressing cell lines had...

Hemoglobin Expression in Nonerythroid Cells: Novel or Ubiquitous?

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Debarchana Saha

2014-01-01

Full Text Available Hemoglobin (Hb is a major protein involved in transport of oxygen (O2. Red blood cells (RBCs contain maximum amount of Hb and because of their unique structure and plasticity they transport O2 to various tissues of the body at an optimal concentration. Recently, it has been reported that, apart from RBCs, Hb is also expressed by nonerythroid cells such as epithelial cells of different origin. The cells expressing Hb are from the tissues where maintenance of O2 homeostasis is of paramount importance. Hb expression has been observed in the epithelial cells from human tissues including lungs, neurons, retina, and endometrium. Our group has recently demonstrated that Hb is expressed by the cervicovaginal epithelial cells. We further showed that, apart from maintaining O2 homeostasis, Hb and the peptides derived from it play an indispensable role in the protection of vaginal epithelium by exhibiting antimicrobial activity. In this review, we discuss the significance of Hb expression in vaginal epithelial cells and its role in the recognition of pathogens thereby reducing the risk and/or severity of inflammation and/or infections and the possible mechanism by which Hb exhibits antimicrobial and antioxidative functions.

NF90 una proteína celular que se une a RNAds inhibe la transactivación del LTR del HIV-1 mediada por TAT

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Silvio Urcuqui Inchima

2001-04-01

Full Text Available

La transactivación del LTR de HIV-1 requiere la interacción de la proteína Tat ( trans-activation transcription con la estructura TAR ( trans-activation response, que se encuentra localizada en el extremo 5’ de todos los transcriptos virales. La interacción de la proteína Tat con TAR forma un precomplejo transcripcional indispensable para la eficiente transcripción del genoma viral.
La interacción de diferentes factores celulares (cdk9 y ciclina T, entre otros con el precomplejo Tat-TAR, constituye un complejo estable que facilita la fosforilación de la subunidad mayor de la RNA polimerasa II, asegurando una eficiente elongación de los transcriptos virales. No se han descripto proteínas capaces de regular negativamente la función de Tat con resultados nefastos para la replicación viral. También se ha descrito otro tipo de proteínas celulares con capacidad de interactuar con TAR. El ejemplo mejor caracterizado es la proteína-kinasa dependiente de RNA (PKR, se autofosforila y mediante fosforilación del factor eIF2, inhibe la síntesis de proteínas. Con el presente trabajo se
pretendió aislar y caracterizar otras proteínas celulares capaces de interactuar con la estructura TAR y estudiar su efecto en la función de Tat.

Prostate stromal cells express the progesterone receptor to control cancer cell mobility.

Science.gov (United States)

Yu, Yue; Lee, Jennifer Suehyun; Xie, Ning; Li, Estelle; Hurtado-Coll, Antonio; Fazli, Ladan; Cox, Michael; Plymate, Stephen; Gleave, Martin; Dong, Xuesen

2014-01-01

Reciprocal interactions between epithelium and stroma play vital roles for prostate cancer development and progression. Enhanced secretions of cytokines and growth factors by cancer associated fibroblasts in prostate tumors create a favorable microenvironment for cancer cells to grow and metastasize. Our previous work showed that the progesterone receptor (PR) was expressed specifically in prostate stromal fibroblasts and smooth muscle cells. However, the expression levels of PR and its impact to tumor microenvironment in prostate tumors are poorly understood. Immunohistochemistry assays are applied to human prostate tissue biopsies. Cell migration, invasion and proliferation assays are performed using human prostate cells. Real-time PCR and ELISA are applied to measure gene expression at molecular levels. Immunohistochemistry assays showed that PR protein levels were decreased in cancer associated stroma when compared with paired normal prostate stroma. Using in vitro prostate stromal cell models, we showed that conditioned media collected from PR positive stromal cells inhibited prostate cancer cell migration and invasion, but had minor suppressive impacts on cancer cell proliferation. PR suppressed the secretion of stromal derived factor-1 (SDF-1) and interlukin-6 (IL-6) by stromal cells independent to PR ligands. Blocking PR expression by siRNA or supplementation of exogenous SDF-1 or IL-6 to conditioned media from PR positive stromal cells counteracted the inhibitory effects of PR to cancer cell migration and invasion. Decreased expression of the PR in cancer associated stroma may contribute to the elevated SDF-1 and IL-6 levels in prostate tumors and enhance prostate tumor progression.

Prostate stromal cells express the progesterone receptor to control cancer cell mobility.

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Yue Yu

Full Text Available Reciprocal interactions between epithelium and stroma play vital roles for prostate cancer development and progression. Enhanced secretions of cytokines and growth factors by cancer associated fibroblasts in prostate tumors create a favorable microenvironment for cancer cells to grow and metastasize. Our previous work showed that the progesterone receptor (PR was expressed specifically in prostate stromal fibroblasts and smooth muscle cells. However, the expression levels of PR and its impact to tumor microenvironment in prostate tumors are poorly understood.Immunohistochemistry assays are applied to human prostate tissue biopsies. Cell migration, invasion and proliferation assays are performed using human prostate cells. Real-time PCR and ELISA are applied to measure gene expression at molecular levels.Immunohistochemistry assays showed that PR protein levels were decreased in cancer associated stroma when compared with paired normal prostate stroma. Using in vitro prostate stromal cell models, we showed that conditioned media collected from PR positive stromal cells inhibited prostate cancer cell migration and invasion, but had minor suppressive impacts on cancer cell proliferation. PR suppressed the secretion of stromal derived factor-1 (SDF-1 and interlukin-6 (IL-6 by stromal cells independent to PR ligands. Blocking PR expression by siRNA or supplementation of exogenous SDF-1 or IL-6 to conditioned media from PR positive stromal cells counteracted the inhibitory effects of PR to cancer cell migration and invasion.Decreased expression of the PR in cancer associated stroma may contribute to the elevated SDF-1 and IL-6 levels in prostate tumors and enhance prostate tumor progression.

Pharmacologic suppression of target cell recognition by engineered T cells expressing chimeric T-cell receptors.

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Alvarez-Vallina, L; Yañez, R; Blanco, B; Gil, M; Russell, S J

2000-04-01

Adoptive therapy with autologous T cells expressing chimeric T-cell receptors (chTCRs) is of potential interest for the treatment of malignancy. To limit possible T-cell-mediated damage to normal tissues that weakly express the targeted tumor antigen (Ag), we have tested a strategy for the suppression of target cell recognition by engineered T cells. Jurkat T cells were transduced with an anti-hapten chTCR tinder the control of a tetracycline-suppressible promoter and were shown to respond to Ag-positive (hapten-coated) but not to Ag-negative target cells. The engineered T cells were then reacted with hapten-coated target cells at different effector to target cell ratios before and after exposure to tetracycline. When the engineered T cells were treated with tetracycline, expression of the chTCR was greatly decreased and recognition of the hapten-coated target cells was completely suppressed. Tetracycline-mediated suppression of target cell recognition by engineered T cells may be a useful strategy to limit the toxicity of the approach to cancer gene therapy.

A Review of Approaches for the Design of Li-Ion BMS Estimation Functions Revue de différentes approches pour l’estimation de l’état de charge de batteries Li-ion

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Di Domenico D.

2013-02-01

Full Text Available This paper aims at comparing different approaches for the estimation of the state of charge of lithium-ion batteries. The main advantages as well as the critical points of the considered techniques are analyzed, highlighting the impact of the cell model precision and complexity on the estimator performance. Among others, the electrical equivalent circuit based technique is selected for further development. The results of a complete procedure from the cell characterization to the online estimation are illustrated. The experimental tests based on the data collected on batteries testing facilities of IFP Energies nouvelles show that the proposed strategy allows a satisfying state of charge real time estimation. Cet article vise à comparer différentes approches pour l’estimation de l’état de charge pour les batteries Li-ion. Les principaux avantages ainsi que les points critiques des différentes techniques sont analysés, en soulignant l’impact de la complexité et de la précision du modèle sur les performances de l’estimateur. La procédure complète, allant de la caractérisation de la cellule jusqu’à l’estimation en ligne de l’état de charge, est présentée pour la modélisation par circuit électrique équivalent. Les tests expérimentaux sur la base des données acquises au laboratoire batteries d’IFP Energies nouvelles montrent que cette stratégie permet d’obtenir un estimateur en temps réel de l’état de charge présentant de bonnes performances.

Expression and significance of Axin2 in pancreatic cancer cells

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ZHANG Tao

2016-05-01

Full Text Available ObjectiveTo investigate the expression of Axin2 in pancreatic cancer cells, and to observe the influence of Axin2 on the proliferation, invasion, and migration of human pancreatic cancer cells (PANC-1. MethodsQuantitative real-time PCR was used to measure the expression of Axin2 in pancreatic cancer cell lines with different invasive abilities (PANC-1, Mia PaCa-2, and BxPC-3 and immortalized normal pancreatic cells (H6C7. PANC-1 cells with low expression were transfected with over-expressed Axin2 plasmid by transient transfection. MTT assay, Transwell assay, and scratch assay were used to determine the proliferation, invasion, and migration of cells transfected with over-expressed Axin2. One-way analysis of variance was used for comparison between multiple groups, and SNK-q test was used for comparison between any two groups. ResultsThe relative expression levels of Axin2 in PANC-1, BxPC-3, Mia PaCa-2, and H6C7 cells were 0.13±0.01, 0.42±0.05, 0.24±0.011, and 1.00±0.00, respectively, and PANC-1 cells had the lowest expression level of Axin2, with significant differences compared with the other cells (all P＜0.05. When PANC-1 cells were transfected with over-expressed Axin2 plasmid, the cells in the over-expression group had a significant increase in the expression level of Axin2 compared with those in the blank group and the negative control group (both P＜0.05. Compared with those in the non-transfection group and the blank group, PANC-1 cells in the over-expression group showed significant reductions in the proliferation, invasion, and migration abilities. ConclusionThe expression of Axin2 is down-regulated in pancreatic cancer cell lines and decreases with the increasing invasion ability, suggesting the role of tumor suppressor gene. High expression of Axin2 can reduce the proliferation, invasion, and migration abilities of PANC-1 cells.

Advantages and Applications of CAR-Expressing Natural Killer Cells

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Wolfgang eGlienke

2015-02-01

Full Text Available In contrast to donor T cells, natural killer (NK cells are known to mediate anti-cancer effects without the risk of inducing graft-versus-host disease (GvHD. In order to improve cytotoxicity against resistant cancer cells, auspicious efforts have been made with chimeric antigen receptor (CAR expressing T- and NK cells. These CAR-modified cells express antigen receptors against tumor-associated surface antigens, thus redirecting the effector cells and enhancing tumor-specific immunosurveillance. However, many cancer antigens are also expressed on healthy tissues, potentially leading to off tumor/ on target toxicity by CAR-engineered cells. In order to control such potentially severe side effects, the insertion of suicide genes into CAR-modified effectors can provide a means for efficient depletion of these cells. While CAR-expressing T cells have entered successfully clinical trials, experience with CAR-engineered NK cells is mainly restricted to pre-clinical investigations and predominantly to NK cell lines. In this review we summarize the data on CAR expressing NK cells focusing on the possible advantage using these short-lived effector cells and discuss the necessity of suicide switches. Furthermore, we address the compliance of such modified NK cells with regulatory requirements as a new field in cellular immunotherapy.

In vitro cytotoxicity of alpha conjugates for human pancreatic cancer cell lines

International Nuclear Information System (INIS)

Qu, C.; Li, Y.; Rizvi, M.A.; Allen, B.; Samra, J.; Smith, R.

2003-01-01

Targeted Alpha therapy (TAT) can inhibit the growth of micrometastases by selectively killing isolated and preangiogenic clusters of cancer cells. The aim of this study is to demonstrate the cytotoxicity of different alpha conjugates in vitro to human metastatic pancreatic cancer cell lines (CAPAN-1, CFPAN-1 and PANC-1). We are labeling the C595 and J591 (non-specific controls) monoclonal antibodies (Mabs) with 213 Bi were performed according to the standard methods in our laboratory. 213 Bi-C595 is specifically cytotoxic to CAPAN-1, CFPAN-1 and PANC-1cell lines in a concentration-dependent fashion. While non-specific alpha conjugates only killed very small fractions of pancreatic cancer cells. These alpha conjugates might be useful agents for the treatment of micro-metastases in pancreatic cancer patients with over-expression of the targeted receptors

Evaluation of Psychoanalytic Oriented Psychotherapy Outcome Using Rorschach and TAT: A Case Study

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Zihniye OKRAY

2017-12-01

Full Text Available Projective techniques especially Rorschach and TAT ( Thematic Apperception Test have a wide variety of assestment areas. These techniques have been used from selection of staff for a appropriate job, giving diagnosis to psychiatric patients, in child services for counseling, selection and evaluation of military personel. Apart from these uses they also have valuable contributions to the efficiency of a certain treatment programs with helping clinicans to evaluate the psychodynamic properties of a client to decide the type, duration and specific issues in the treatment programme (Deabler, 1947, Weiner, 1997, Tunaboylu-İkiz, 2001, 2002, 2010,2011, Anzieu & Chabert, 2011. In this study a case who was treated with psychodynamic oriented psychotherapy for 2 years the outcome of the threapy evaluated with Rorschach and TAT. In the first assestment before the psychothreapy began the Detail responses given by the patient was to much inorder to protect himself from the dangers coming from the real world.The content of the responses also showed the same charasteristic with using the same theme all over the full protocol.Case’s problems around his self-representaion, self, identification- differences between gender and object relations was evaluated with TAT that showed object loss was the main problematic. After 2 years with the termination of the threapy the second evaluation was done. In this second evaluation the case led himself more freely to the test material with less resistance. In the second evaluation; the case’s cognitive processes and using of words are more rich wch represents high cognitive and entellectual capacities. He is less resistant to unconscious material, sexual contents coming up in responses with more intellectual ways. With these two assestment the efficiency of psychodynamic oriented psychothreapy was proved. Although the case’s perception of the real world still contains some aspects of threads the second evaluation

Glioblastoma formation from cell population depleted of Prominin1-expressing cells.

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Kenji Nishide

2009-08-01

Full Text Available Prominin1 (Prom1, also known as CD133 in human has been widely used as a marker for cancer stem cells (CSCs, which self-renew and are tumorigenic, in malignant tumors including glioblastoma multiforme (GBM. However, there is other evidence showing that Prom1-negative cancer cells also form tumors in vivo. Thus it remains controversial whether Prom1 is a bona fide marker for CSCs. To verify if Prom1-expressing cells are essential for tumorigenesis, we established a mouse line, whose Prom1-expressing cells can be eliminated conditionally by a Cre-inducible DTA gene on the Prom1 locus together with a tamoxifen-inducible CreER(TM, and generated glioma-initiating cells (GICs-LD by overexpressing both the SV40 Large T antigen and an oncogenic H-Ras(L61 in neural stem cells of the mouse line. We show here that the tamoxifen-treated GICs-LD (GICs-DTA form tumor-spheres in culture and transplantable GBM in vivo. Thus, our studies demonstrate that Prom1-expressing cells are dispensable for gliomagenesis in this mouse model.

Analysis of in vitro toxicity of five cell-penetrating peptides by metabolic profiling

International Nuclear Information System (INIS)

Kilk, Kalle; Mahlapuu, Riina; Soomets, Ursel; Langel, Ulo

2009-01-01

Cell-penetrating peptides (CPPs) are promising candidates for safe and efficient delivery vectors for a wide range of cargoes. However, any compound that is internalized into cells may affect the cell homeostasis. The plethora of possible biological responses makes large scale 'omics' studies appealing approaches for hunting any unsuspected side-effects and evaluate the toxicity of drug candidates. Here we have compared the alterations in cytosolic metabolome of CHO cells caused by five representatives of the most common CPPs: transportan (TP), penetratin (pAntp), HIV Tat derived peptide (pTat), nonaarginine (R 9 ) and model amphipathic peptide (MAP). Analysis was done by liquid chromatography-mass spectrometry techniques, principal component analysis and heatmap displays. Results showed that the intracellular metabolome was the most affected by TP followed by pTat and MAP. Only minor changes could be associated with pAntp or R 9 treatment. The cells could recover from a treatment with 5 μM TP, but no recovery was observed at higher concentration. Both metabolomic and control experiments showed that TP affected cellular redox potential, depleted energy and the pools of purines and pyrimidines. In conclusion, we have performed a metabolomic analysis comparing the safety of cell-penetrating peptides and demonstrate the toxicity of one of them.

Geometry of the Gene Expression Space of Individual Cells.

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Yael Korem

2015-07-01

Full Text Available There is a revolution in the ability to analyze gene expression of single cells in a tissue. To understand this data we must comprehend how cells are distributed in a high-dimensional gene expression space. One open question is whether cell types form discrete clusters or whether gene expression forms a continuum of states. If such a continuum exists, what is its geometry? Recent theory on evolutionary trade-offs suggests that cells that need to perform multiple tasks are arranged in a polygon or polyhedron (line, triangle, tetrahedron and so on, generally called polytopes in gene expression space, whose vertices are the expression profiles optimal for each task. Here, we analyze single-cell data from human and mouse tissues profiled using a variety of single-cell technologies. We fit the data to shapes with different numbers of vertices, compute their statistical significance, and infer their tasks. We find cases in which single cells fill out a continuum of expression states within a polyhedron. This occurs in intestinal progenitor cells, which fill out a tetrahedron in gene expression space. The four vertices of this tetrahedron are each enriched with genes for a specific task related to stemness and early differentiation. A polyhedral continuum of states is also found in spleen dendritic cells, known to perform multiple immune tasks: cells fill out a tetrahedron whose vertices correspond to key tasks related to maturation, pathogen sensing and communication with lymphocytes. A mixture of continuum-like distributions and discrete clusters is found in other cell types, including bone marrow and differentiated intestinal crypt cells. This approach can be used to understand the geometry and biological tasks of a wide range of single-cell datasets. The present results suggest that the concept of cell type may be expanded. In addition to discreet clusters in gene-expression space, we suggest a new possibility: a continuum of states within a

The C Terminus of the Nucleoprotein of Influenza A Virus Delivers Antigens Transduced by Tat to the trans-Golgi Network and Promotes an Efficient Presentation through HLA Class I

OpenAIRE

Bettosini, Francesca; Fiorillo, Maria Teresa; Magnacca, Adriana; Leone, Laura; Torrisi, Maria Rosaria; Sorrentino, Rosa

2005-01-01

Cytotoxic T lymphocytes (CTLs) are the most powerful weapon of the immune system to eliminate cells infected by intracellular parasites or tumors. However, very often, escape mechanisms overcome CTL immune surveillance by impairing the classical HLA class I antigen-processing pathway. Here, we describe a strategy for CTL activation based on the ability of Tat to mediate transcellular delivery of viral proteins encompassing HLA class I-restricted epitopes. In this system, the recombinant prote...

CD133 expression in chemo-resistant Ewing sarcoma cells

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Kovar Heinrich

2010-03-01

Full Text Available Abstract Background Some human cancers demonstrate cellular hierarchies in which tumor-initiating cancer stem cells generate progeny cells with reduced tumorigenic potential. This cancer stem cell population is proposed to be a source of therapy-resistant and recurrent disease. Ewing sarcoma family tumors (ESFT are highly aggressive cancers in which drug-resistant, relapsed disease remains a significant clinical problem. Recently, the cell surface protein CD133 was identified as a putative marker of tumor-initiating cells in ESFT. We evaluated ESFT tumors and cell lines to determine if high levels of CD133 are associated with drug resistance. Methods Expression of the CD133-encoding PROM1 gene was determined by RT-PCR in ESFT tumors and cell lines. CD133 protein expression was assessed by western blot, FACS and/or immunostaining. Cell lines were FACS-sorted into CD133+ and CD133- fractions and proliferation, colony formation in soft agar, and in vivo tumorigenicity compared. Chemosensitivity was measured using MTS (3-(4,5-dimethylthiazol-2-yl-5-(3-carboxy-methoxyphenyl-2-(4-sulfophenyl-2H-tetrazolium assays. Results PROM1 expression was either absent or extremely low in most tumors. However, PROM1 was highly over-expressed in 4 of 48 cases. Two of the 4 patients with PROM1 over-expressing tumors rapidly succumbed to primary drug-resistant disease and two are long-term, event-free survivors. The expression of PROM1 in ESFT cell lines was similarly heterogeneous. The frequency of CD133+ cells ranged from 2-99% and, with one exception, no differences in the chemoresistance or tumorigenicity of CD133+ and CD133- cell fractions were detected. Importantly, however, the STA-ET-8.2 cell line was found to retain a cellular hierarchy in which relatively chemo-resistant, tumorigenic CD133+ cells gave rise to relatively chemo-sensitive, less tumorigenic, CD133- progeny. Conclusions Up to 10% of ESFT express high levels of PROM1. In some tumors and cell

B cell lymphomas express CX3CR1 a non-B cell lineage adhesion molecule

DEFF Research Database (Denmark)

Andreasson, U.; Ek, S.; Merz, H.

2008-01-01

normally is not expressed on B cells, is expressed both at the mRNA and protein level in several subtypes of lymphoma. CX3CR1 has also shown to be involved in the homing to specific tissues that express the ligand, CX3CL1, in breast and prostate cancer and may thus be involved in dissemination of lymphoma......To study the differential expression of cell membrane-bound receptors and their potential role in growth and/or survival of the tumor cells, highly purified follicular lymphoma cells were analyzed, using gene expression analysis, and compared to non-malignant B cell populations. Filtering...... the genome for overexpressed genes coding for cell membrane-bound proteins/receptors resulted in a hit list of 27 identified genes. Among these, we have focused on the aberrant over expression of CX3CR1, in different types of B cell lymphoma, as compared to non-malignant B cells. We show that CX3CR1, which...

Behavioral experience induces zif268 expression in mature granule cells but suppresses its expression in immature granule cells

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Kylie A. Huckleberry

2015-08-01

Full Text Available Thousands of neurons are born each day in the dentate gyrus (DG, but many of these cells die before reaching maturity. Both death and survival of adult-born neurons are regulated by neuronal activity in DG. The immediate-early gene (IEG zif268 is an important mediator of these effects, as its expression is induced by neural activity and knockout of zif268 impairs survival of adult-born neurons (Veyrac et al., 2013. Despite the apparent importance of zif268 for adult neurogenesis, its behavior-induced expression has not been fully characterized in adult-born neurons. Here we characterize behavior-evoked expression of zif268 in mature and newborn dentate granule cells (DGCs. In the general granule cell population, zif268 expression peaked 1 hour after novel environment exposure and returned to baseline by 8 hours post-exposure. However, in the doublecortin-positive (DCX+ immature neurons, zif268 expression was suppressed relative to home cage for at least 8 hours post-exposure. We next determined that exposure to water maze training, an enriched environment, or a novel environment caused approximately equal suppression of zif268 expression in DCX+ cells and approximately equal activation of zif268 in the general DGC population and in 6-week-old adult-born neurons. Finally, we asked whether zif268 suppression varied as a function of age within the DCX+ population, which ranges in age from 0 to approximately 4 weeks. Novel environment exposure had no significant effect on zif268 expression in 2- or 4-week-old BrdU-labeled neurons, but it significantly suppressed zif268 expression in 3-week-old neurons. In summary, behavioral experience transiently activated expression of zif268 in mature DGCs but caused a more long-lasting suppression of zif268 expression in immature, adult-born DGCs. We hypothesize that zif268 suppression inhibits memory-related synaptic plasticity in immature DGCs or mediates learning-induced apoptosis of immature adult

Human thymic epithelial cells express functional HLA-DP molecules

DEFF Research Database (Denmark)

Jørgensen, A; Röpke, C; Nielsen, M

1996-01-01

T lymphocytes, we examined whether human thymic epithelial cells (TEC) expressed HLA-DP molecules. We present evidence that TEC obtained from short time culture express low but significant levels of HLA-DP molecules. The expression of HLA-DP molecules was comparable to or higher than the expression...... of HLA-DP allospecific primed lymphocyte typing (PLT) CD4 T cell lines. IFN-gamma treatment strongly upregulated the HLA-DP allospecific PLT responses whereas other PLT responses remained largely unchanged. In conclusion, these data indicate that human thymus epithelial cells express significant levels...

Soluble expression of recomb inant cMyc, Klf4, Oct4, and Sox2 proteins in bacteria and transduction into living cells

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Guo-Dan Liu

2017-04-01

Full Text Available AIM: To develop a new method to produce recombinant reprogramming proteins, cMyc, Klf4, Oct4, and Sox2, in soluble format with low cost for the generation of induced pluripotent stem cells (iPSCs. METHODS: A short polypeptide sequence derived from the HIV trans-activator of transcription protein (TAT and the nucleus localization signal (NLS polypeptide were fused to the N terminus of the reprogramming proteins and they were constructed into pCold-SUMO vector which can extremely improve the solubility of recombinant proteins. Then these vector plasmids were transformed into E. coli BL21 (DE3 Chaperone competent cells for amplification. The solubility of these recombinant proteins was determined by SDS-PAGE and Coomassie brilliant blue staining. The recombinant proteins were purified by Ni-NTA resin and identified by Western blot. The transduction of these proteins into HEK 293T cells were evaluated by immunofluorescence staining. RESULTS: These four reprogramming proteins could be produced in soluble format in pCold-SUMO expression vector system with the assistance of chaperone proteins in bacteria. The proteins were purified successfully with a purity of over 70% with a relative high transduction rate into 293 cells. CONCLUSION: The results in the present study indicate the four important reprogramming proteins, cMyc, Klf4, Oct4, and Sox2, can be produced in soluble format in bacteria with low cost. Our new method thus might be expected to greatly contribute to the future study of iPSCs.

Absence of annexin I expression in B-cell non-Hodgkin's lymphomas and cell lines

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Gopalakrishnan Velliyur K

2004-03-01

Full Text Available Abstract Background Annexin I, one of the 20 members of the annexin family of calcium and phospholipid-binding proteins, has been implicated in diverse biological processes including signal transduction, mediation of apoptosis and immunosuppression. Previous studies have shown increased annexin I expression in pancreatic and breast cancers, while it is absent in prostate and esophageal cancers. Results Data presented here show that annexin I mRNA and protein are undetectable in 10 out of 12 B-cell lymphoma cell lines examined. Southern blot analysis indicates that the annexin I gene is intact in B-cell lymphoma cell lines. Aberrant methylation was examined as a cause for lack of annexin I expression by treating cells 5-Aza-2-deoxycytidine. Reexpression of annexin I was observed after prolonged treatment with the demethylating agent indicating methylation may be one of the mechanisms of annexin I silencing. Treatment of Raji and OMA-BL-1 cells with lipopolysaccharide, an inflammation inducer, and with hydrogen peroxide, a promoter of oxidative stress, also failed to induce annexin I expression. Annexin I expression was examined in primary lymphoma tissues by immunohistochemistry and presence of annexin I in a subset of normal B-cells and absence of annexin I expression in the lymphoma tissues were observed. These results show that annexin I is expressed in normal B-cells, and its expression is lost in all primary B-cell lymphomas and 10 of 12 B-cell lymphoma cell lines. Conclusions Our results suggest that, similar to prostate and esophageal cancers, annexin I may be an endogenous suppressor of cancer development, and loss of annexin I may contribute to B-cell lymphoma development.

Novel method for isolation of murine clara cell secretory protein-expressing cells with traces of stemness.

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Xiao-Yang Wang

Full Text Available Clara cells are non-ciliated, secretory bronchiolar epithelial cells that serve to detoxify harmful inhaled substances. Clara cells also function as stem/progenitor cells for repair in the bronchioles. Clara cell secretory protein (CCSP is specifically expressed in pulmonary Clara cells and is widely used as a Clara cell marker. In addition CCSP promoter is commonly used to direct gene expression into the lung in transgenic models. The discovery of CCSP immunoreactivity in plasma membranes of airway lining cells prompted us to explore the possibility of enriching Clara cells by flow cytometry. We established a novel and simple method for the isolation of CCSP-expressing cell Clara cells using a combination of mechanical and enzymatic dissociation followed by flow cytometry sorting technology. We showed that ∼25% of dissociated cells from whole lung expressed CCSP. In the resulting preparation, up to 98% of cells expressed CCSP. Notably, we found that several common stem cell markers including CD44, CD133, Sca-1 and Sox2 were expressed in CCSP(+ cells. Moreover, CCSP(+ cells were able to form spheroid colonies in vitro with 0.97‰ efficiency. Parallel studies in vivo confirmed that a small population of CCSP(-expressing cells in mouse airways also demonstrates stem cell-like properties such as label retention and harboring rare bronchioalveolar stem cells (BASCs in terminal bronchioles (TBs. We conclude that CCSP(+ cells exhibit a number of stem cell-like features including stem cell marker expression, bronchosphere colony formation and self-renewal ability. Clara cell isolation by flow cytometry sorting is a useful method for investigating the function of primary Clara cells in stem cell research and mouse models.

An HIV feedback resistor: auto-regulatory circuit deactivator and noise buffer.

Science.gov (United States)

Weinberger, Leor S; Shenk, Thomas

2007-01-01

Animal viruses (e.g., lentiviruses and herpesviruses) use transcriptional positive feedback (i.e., transactivation) to regulate their gene expression. But positive-feedback circuits are inherently unstable when turned off, which presents a particular dilemma for latent viruses that lack transcriptional repressor motifs. Here we show that a dissipative feedback resistor, composed of enzymatic interconversion of the transactivator, converts transactivation circuits into excitable systems that generate transient pulses of expression, which decay to zero. We use HIV-1 as a model system and analyze single-cell expression kinetics to explore whether the HIV-1 transactivator of transcription (Tat) uses a resistor to shut off transactivation. The Tat feedback circuit was found to lack bi-stability and Tat self-cooperativity but exhibited a pulse of activity upon transactivation, all in agreement with the feedback resistor model. Guided by a mathematical model, biochemical and genetic perturbation of the suspected Tat feedback resistor altered the circuit's stability and reduced susceptibility to molecular noise, in agreement with model predictions. We propose that the feedback resistor is a necessary, but possibly not sufficient, condition for turning off noisy transactivation circuits lacking a repressor motif (e.g., HIV-1 Tat). Feedback resistors may be a paradigm for examining other auto-regulatory circuits and may inform upon how viral latency is established, maintained, and broken.

The Expression of BTS-2 Enhances Cell Growth and Invasiveness in Renal Cell Carcinoma.

Science.gov (United States)

Pham, Quoc Thang; Oue, Naohide; Yamamoto, Yuji; Shigematsu, Yoshinori; Sekino, Yohei; Sakamoto, Naoya; Sentani, Kazuhiro; Uraoka, Naohiro; Tiwari, Mamata; Yasui, Wataru

2017-06-01

Renal cell carcinoma (RCC) is one of the most common types of cancer in developed countries. Bone marrow stromal cell antigen 2 (BST2) gene, which encodes BST2 transmembrane glycoprotein, is overexpressed in several cancer types. In the present study, we analyzed the expression and function of BST2 in RCC. BST2 expression was analyzed by immunohistochemistry in 123 RCC cases. RNA interference was used to inhibit BST2 expression in a RCC cell line. Immunohistochemical analysis showed that 32% of the 123 RCC cases were positive for BST2. BST2 expression was positively associated with tumour stage. Furthermore, BST2 expression was an independent predictor of survival in patients with RCC. BST2 siRNA-transfected Caki-1 cells displayed significantly reduced cell growth and invasive activity relative to negative control siRNA-transfected cells. These results suggest that BST2 plays an important role in the progression of RCC. Because BST2 is expressed on the cell membrane, BST2 is a good therapeutic target for RCC. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Amélioration de l'état nutritionnel des enfants au Ghana, au Kenya ...

International Development Research Centre (IDRC) Digital Library (Canada)

Les chercheurs ont déterminé que les changements sur le plan de la nutrition en Afrique sont l'une des principales causes de l'épidémie croissante de maladies non transmissibles (MNT). Ce projet de recherche évaluera les habitudes alimentaires et l'état nutritionnel des enfants pour jeter les bases d'un projet de ...

Efflux protein expression in human stem cell-derived retinal pigment epithelial cells.

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Kati Juuti-Uusitalo

Full Text Available Retinal pigment epithelial (RPE cells in the back of the eye nourish photoreceptor cells and form a selective barrier that influences drug transport from the blood to the photoreceptor cells. At the molecular level, ATP-dependent efflux transporters have a major role in drug delivery in human RPE. In this study, we assessed the relative expression of several ATP-dependent efflux transporter genes (MRP1, -2, -3, -4, -5, -6, p-gp, and BCRP, the protein expression and localization of MRP1, MRP4, and MRP5, and the functionality of MRP1 efflux pumps at different maturation stages of undifferentiated human embryonic stem cells (hESC and RPE derived from the hESC (hESC-RPE. Our findings revealed that the gene expression of ATP-dependent efflux transporters MRP1, -3, -4, -5, and p-gp fluctuated during hESC-RPE maturation from undifferentiated hESC to fusiform, epithelioid, and finally to cobblestone hESC-RPE. Epithelioid hESC-RPE had the highest expression of MRP1, -3, -4, and P-gp, whereas the most mature cobblestone hESC-RPE had the highest expression of MRP5 and MRP6. These findings indicate that a similar efflux protein profile is shared between hESC-RPE and the human RPE cell line, ARPE-19, and suggest that hESC-RPE cells are suitable in vitro RPE models for drug transport studies. Embryonic stem cell model might provide a novel tool to study retinal cell differentiation, mechanisms of RPE-derived diseases, drug testing and targeted drug therapy.

Activation of p44/42 in Human Natural Killer Cells Decreases Cell-surface Protein Expression: Relationship to Tributyltin-induced alterations of protein expression

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Dudimah, Fred D.; Abraha, Abraham; Wang, Xiaofei; Whalen, Margaret M.

2010-01-01

Tributyltin (TBT) activates the mitogen activated protein kinase (MAPK), p44/42 in human natural killer (NK) cells. TBT also reduces NK cytotoxic function and decreases the expression of several NK-cell proteins. To understand the role that p44/42 activation plays in TBT-induced loss of NK cell function, we have investigated how selective activation of p44/42 by phorbol 12-myristate 13-acetate (PMA) affects NK cells. Previously we showed that PMA caused losses of lytic function similar to those seen with TBT exposures. Here we examined activation of p44/42 in the regulation of NK-cell protein expression and how this regulation may explain the protein expression changes seen with TBT exposures. NK cells exposed to PMA were examined for levels of cell-surface proteins, granzyme mRNA, and perforin mRNA expression. The expression of CD11a, CD16, CD18, and CD56 were reduced, perforin mRNA levels were unchanged and granzyme mRNA levels were increased. To verify that activation of p44/42 was responsible for the alterations seen in CD11a, CD16, CD18, and CD56 with PMA, NK cells were treated with the p44/42 pathway inhibitor (PD98059) prior to PMA exposures. In the presence of PD98059, PMA caused no decreases in the expression of the cell-surface proteins. Results of these studies indicate that the activation of p44/42 may lead to the loss of NK cell cytotoxic function by decreasing the expression of CD11a, CD16, CD18, and CD56. Further, activation of p44/42 appears to be at least in part responsible for the TBT-induced decreases in expression of CD16, CD18, and CD56. PMID:20883105

HIV Cell-to-Cell Spread Results in Earlier Onset of Viral Gene Expression by Multiple Infections per Cell.

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Mikaël Boullé

2016-11-01

Full Text Available Cell-to-cell spread of HIV, a directed mode of viral transmission, has been observed to be more rapid than cell-free infection. However, a mechanism for earlier onset of viral gene expression in cell-to-cell spread was previously uncharacterized. Here we used time-lapse microscopy combined with automated image analysis to quantify the timing of the onset of HIV gene expression in a fluorescent reporter cell line, as well as single cell staining for infection over time in primary cells. We compared cell-to-cell spread of HIV to cell-free infection, and limited both types of transmission to a two-hour window to minimize differences due to virus transit time to the cell. The mean time to detectable onset of viral gene expression in cell-to-cell spread was accelerated by 19% in the reporter cell line and by 35% in peripheral blood mononuclear cells relative to cell-free HIV infection. Neither factors secreted by infected cells, nor contact with infected cells in the absence of transmission, detectably changed onset. We recapitulated the earlier onset by infecting with multiple cell-free viruses per cell. Surprisingly, the acceleration in onset of viral gene expression was not explained by cooperativity between infecting virions. Instead, more rapid onset was consistent with a model where the fastest expressing virus out of the infecting virus pool sets the time for infection independently of the other co-infecting viruses.

Polyclonal T-cells express CD1a in Langerhans cell histiocytosis (LCH lesions.

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Jennifer A West

Full Text Available Langerhans cell histiocytosis (LCH is a complex and poorly understood disorder that has characteristics of both inflammatory and neoplastic disease. By using eight-colour flow cytometry, we have identified a previously unreported population of CD1a(+/CD3(+ T-cells in LCH lesions. The expression of CD1a is regarded as a hallmark of this disease; however, it has always been presumed that it was only expressed by pathogenic Langerhans cells (LCs. We have now detected CD1a expression by a range of T-cell subsets within all of the LCH lesions that were examined, establishing that CD1a expression in these lesions is no longer restricted to pathogenic LCs. The presence of CD1a(+ T-cells in all of the LCH lesions that we have studied to date warrants further investigation into their biological function to determine whether these cells are important in the pathogenesis of LCH.

Autoimmune Regulator (AIRE) Is Expressed in Spermatogenic Cells, and It Altered the Expression of Several Nucleic-Acid-Binding and Cytoskeletal Proteins in Germ Cell 1 Spermatogonial (GC1-spg) Cells.

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Radhakrishnan, Karthika; Bhagya, Kongattu P; Kumar, Anil Tr; Devi, Anandavalli N; Sengottaiyan, Jeeva; Kumar, Pradeep G

2016-08-01

Autoimmune regulator (AIRE) is a gene associated with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED). AIRE is expressed heavily in the thymic epithelial cells and is involved in maintaining self-tolerance through regulating the expression of tissue-specific antigens. The testes are the most predominant extrathymic location where a heavy expression of AIRE is reported. Homozygous Aire-deficient male mice were infertile, possibly due to impaired spermatogenesis, deregulated germ cell apoptosis, or autoimmunity. We report that AIRE is expressed in the testes of neonatal, adolescent, and adult mice. AIRE expression was detected in glial cell derived neurotrophic factor receptor alpha (GFRα)(+) (spermatogonia), GFRα(-)/synaptonemal complex protein (SCP3)(+) (meiotic), and GFRα(-)/Phosphoglycerate kinase 2 (PGK2)(+) (postmeiotic) germ cells in mouse testes. GC1-spg, a germ-cell-derived cell line, did not express AIRE. Retinoic acid induced AIRE expression in GC1-spg cells. Ectopic expression of AIRE in GC1-spg cells using label-free LC-MS/MS identified a total of 371 proteins that were differentially expressed. 100 proteins were up-regulated, and 271 proteins were down-regulated. Data are available via ProteomeXchange with identifier PXD002511. Functional analysis of the differentially expressed proteins showed increased levels of various nucleic-acid-binding proteins and transcription factors and a decreased level of various cytoskeletal and structural proteins in the AIRE overexpressing cells as compared with the empty vector-transfected controls. The transcripts of a select set of the up-regulated proteins were also elevated. However, there was no corresponding decrease in the mRNA levels of the down-regulated set of proteins. Molecular function network analysis indicated that AIRE influenced gene expression in GC1-spg cells by acting at multiple levels, including transcription, translation, RNA processing, protein transport, protein

Exosomes from asbestos-exposed cells modulate gene expression in mesothelial cells.

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Munson, Phillip; Lam, Ying-Wai; Dragon, Julie; MacPherson, Maximilian; Shukla, Arti

2018-03-19

Asbestos exposure is a determinate cause of many diseases, such as mesothelioma, fibrosis, and lung cancer, and poses a major human health hazard. At this time, there are no identified biomarkers to demarcate asbestos exposure before the presentation of disease and symptoms, and there is only limited understanding of the underlying biology that governs asbestos-induced disease. In our study, we used exosomes, 30-140 nm extracellular vesicles, to gain insight into these knowledge gaps. As inhaled asbestos is first encountered by lung epithelial cells and macrophages, we hypothesize that asbestos-exposed cells secrete exosomes with signature proteomic cargo that can alter the gene expression of mesothelial cells, contributing to disease outcomes like mesothelioma. In the present study using lung epithelial cells (BEAS2B) and macrophages (THP-1), we first show that asbestos exposure causes changes in abundance of some proteins in the exosomes secreted from these cells. Furthermore, exposure of human mesothelial cells (HPM3) to these exosomes resulted in gene expression changes related to epithelial-to-mesenchymal transition and other cancer-related genes. This is the first report to indicate that asbestos-exposed cells secrete exosomes with differentially abundant proteins and that those exosomes have a gene-altering effect on mesothelial cells.-Munson, P., Lam, Y.-W., Dragon, J. MacPherson, M., Shukla, A. Exosomes from asbestos-exposed cells modulate gene expression in mesothelial cells.

Characterization of TLX expression in neural stem cells and progenitor cells in adult brains.

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Li, Shengxiu; Sun, Guoqiang; Murai, Kiyohito; Ye, Peng; Shi, Yanhong

2012-01-01

TLX has been shown to play an important role in regulating the self-renewal and proliferation of neural stem cells in adult brains. However, the cellular distribution of endogenous TLX protein in adult brains remains to be elucidated. In this study, we used immunostaining with a TLX-specific antibody to show that TLX is expressed in both neural stem cells and transit-amplifying neural progenitor cells in the subventricular zone (SVZ) of adult mouse brains. Then, using a double thymidine analog labeling approach, we showed that almost all of the self-renewing neural stem cells expressed TLX. Interestingly, most of the TLX-positive cells in the SVZ represented the thymidine analog-negative, relatively quiescent neural stem cell population. Using cell type markers and short-term BrdU labeling, we demonstrated that TLX was also expressed in the Mash1+ rapidly dividing type C cells. Furthermore, loss of TLX expression dramatically reduced BrdU label-retaining neural stem cells and the actively dividing neural progenitor cells in the SVZ, but substantially increased GFAP staining and extended GFAP processes. These results suggest that TLX is essential to maintain the self-renewing neural stem cells in the SVZ and that the GFAP+ cells in the SVZ lose neural stem cell property upon loss of TLX expression. Understanding the cellular distribution of TLX and its function in specific cell types may provide insights into the development of therapeutic tools for neurodegenerative diseases by targeting TLX in neural stem/progenitors cells.

A cancer specific cell-penetrating peptide, BR2, for the efficient delivery of an scFv into cancer cells.

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Ki Jung Lim

Full Text Available Cell-penetrating peptides (CPPs have proven very effective as intracellular delivery vehicles for various therapeutics. However, there are some concerns about non-specific penetration and cytotoxicity of CPPs for effective cancer treatments. Herein, based on the cell-penetrating motif of an anticancer peptide, buforin IIb, we designed several CPP derivatives with cancer cell specificity. Among the derivatives, a 17-amino acid peptide (BR2 was found to have cancer-specificity without toxicity to normal cells. After specifically targeting cancer cells through interaction with gangliosides, BR2 entered cells via lipid-mediated macropinocytosis. Moreover, BR2 showed higher membrane translocation efficiency than the well-known CPP Tat (49-57. The capability of BR2 as a cancer-specific drug carrier was demonstrated by fusion of BR2 to a single-chain variable fragment (scFv directed toward a mutated K-ras (G12V. BR2-fused scFv induced a higher degree of apoptosis than Tat-fused scFv in K-ras mutated HCT116 cells. These results suggest that the novel cell-penetrating peptide BR2 has great potential as a useful drug delivery carrier with cancer cell specificity.

A cancer specific cell-penetrating peptide, BR2, for the efficient delivery of an scFv into cancer cells.

Science.gov (United States)

Lim, Ki Jung; Sung, Bong Hyun; Shin, Ju Ri; Lee, Young Woong; Kim, Da Jung; Yang, Kyung Seok; Kim, Sun Chang

2013-01-01

Cell-penetrating peptides (CPPs) have proven very effective as intracellular delivery vehicles for various therapeutics. However, there are some concerns about non-specific penetration and cytotoxicity of CPPs for effective cancer treatments. Herein, based on the cell-penetrating motif of an anticancer peptide, buforin IIb, we designed several CPP derivatives with cancer cell specificity. Among the derivatives, a 17-amino acid peptide (BR2) was found to have cancer-specificity without toxicity to normal cells. After specifically targeting cancer cells through interaction with gangliosides, BR2 entered cells via lipid-mediated macropinocytosis. Moreover, BR2 showed higher membrane translocation efficiency than the well-known CPP Tat (49-57). The capability of BR2 as a cancer-specific drug carrier was demonstrated by fusion of BR2 to a single-chain variable fragment (scFv) directed toward a mutated K-ras (G12V). BR2-fused scFv induced a higher degree of apoptosis than Tat-fused scFv in K-ras mutated HCT116 cells. These results suggest that the novel cell-penetrating peptide BR2 has great potential as a useful drug delivery carrier with cancer cell specificity.

Gene expression of manganese superoxide dismutase in human glioma cells

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Novi S. Hardiany

2010-02-01

Full Text Available Aim This study analyze the MnSOD gene expression as endogenous antioxidant in human glioma cells compared with leucocyte cells as control.Methods MnSOD gene expression of 20 glioma patients was analyzed by measuring the relative expression of mRNA and enzyme activity of MnSOD in brain and leucocyte cells. The relative expression of mRNA MnSOD was determined by using quantitative Real Time RT-PCR and the enzyme activity of MnSOD using biochemical kit assay (xantine oxidase inhibition. Statistic analysis for mRNA and enzyme activity of MnSOD was performed using Kruskal Wallis test.Results mRNA of MnSOD in glioma cells of 70% sample was 0.015–0.627 lower, 10% was 1.002-1.059 and 20% was 1.409-6.915 higher than in leucocyte cells. Also the specific activity of MnSOD enzyme in glioma cells of 80% sample showed 0,064-0,506 lower and 20% sample was 1.249-2.718 higher than in leucocyte cells.Conclusion MnSOD gene expression in human glioma cells are significantly lower than its expression in leucocytes cells. (Med J Indones 2010; 19:21-5Keywords : MnSOD, glioma, gene expression

Expression of cadherin and NCAM in human small cell lung cancer cell lines and xenografts

DEFF Research Database (Denmark)

Rygaard, K; Møller, C; Bock, E

1992-01-01

characterised, the cadherin family and the Ig superfamily member, neural cell adhesion molecule (NCAM). We investigated expression of these two adhesion molecule families in small cell lung cancer (SCLC) cell lines and xenografts by immunoblotting. Nineteen tumours established from 15 patients with SCLC were......Tumour cell adhesion, detachment and aggregation seem to play an important part in tumour invasion and metastasis, and numerous cell adhesion molecules are expressed by tumour cells. Several families of cell-cell adhesion molecules have been described, of which two groups are particularly well...... embryonic development, which may play a role in connection with tumour invasion and metastasis, was found in 14/18 NCAM expressing SCLC tumours. Individual tumours grown as cell lines and as nude mouse xenografts showed no qualitative differences in cadherin or NCAM expression....

Sécurité d'État et insécurité nationale au Mali : les logiques ...

African Journals Online (AJOL)

PhD, Socio économiste, Directeur, CERNES, Bamako, Mali. .... Au regard de la référence que constitue la définition sécuritaire régalienne de l'État et de son monopole .... Sur le plan économique, le cycle accumulation, rupture et reconstitution.

Inflammation increases cells expressing ZSCAN4 and progenitor cell markers in the adult pancreas

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Azuma, Sakiko; Yokoyama, Yukihiro; Yamamoto, Akiko; Kyokane, Kazuhiro; Niida, Shumpei; Ishiguro, Hiroshi; Ko, Minoru S. H.

2013-01-01

We have recently identified the zinc finger and SCAN domain containing 4 (Zscan4), which is transiently expressed and regulates telomere elongation and genome stability in mouse embryonic stem (ES) cells. The aim of this study was to examine the expression of ZSCAN4 in the adult pancreas and elucidate the role of ZSCAN4 in tissue inflammation and subsequent regeneration. The expression of ZSCAN4 and other progenitor or differentiated cell markers in the human pancreas was immunohistochemically examined. Pancreas sections of alcoholic or autoimmune pancreatitis patients before and under maintenance corticosteroid treatment were used in this study. In the adult human pancreas a small number of ZSCAN4-positive (ZSCAN4+) cells are present among cells located in the islets of Langerhans, acini, ducts, and oval-shaped cells. These cells not only express differentiated cell markers for each compartment of the pancreas but also express other tissue stem/progenitor cell markers. Furthermore, the number of ZSCAN4+ cells dramatically increased in patients with chronic pancreatitis, especially in the pancreatic tissues of autoimmune pancreatitis actively regenerating under corticosteroid treatment. Interestingly, a number of ZSCAN4+ cells in the pancreas of autoimmune pancreatitis returned to the basal level after 1 yr of maintenance corticosteroid treatment. In conclusion, coexpression of progenitor cell markers and differentiated cell markers with ZSCAN4 in each compartment of the pancreas may indicate the presence of facultative progenitors for both exocrine and endocrine cells in the adult pancreas. PMID:23599043

Decreased expression of cell adhesion genes in cancer stem-like cells isolated from primary oral squamous cell carcinomas.

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Mishra, Amrendra; Sriram, Harshini; Chandarana, Pinal; Tanavde, Vivek; Kumar, Rekha V; Gopinath, Ashok; Govindarajan, Raman; Ramaswamy, S; Sadasivam, Subhashini

2018-05-01

The goal of this study was to isolate cancer stem-like cells marked by high expression of CD44, a putative cancer stem cell marker, from primary oral squamous cell carcinomas and identify distinctive gene expression patterns in these cells. From 1 October 2013 to 4 September 2015, 76 stage III-IV primary oral squamous cell carcinoma of the gingivobuccal sulcus were resected. In all, 13 tumours were analysed by immunohistochemistry to visualise CD44-expressing cells. Expression of CD44 within The Cancer Genome Atlas-Head and Neck Squamous Cell Carcinoma RNA-sequencing data was also assessed. Seventy resected tumours were dissociated into single cells and stained with antibodies to CD44 as well as CD45 and CD31 (together referred as Lineage/Lin). From 45 of these, CD44 + Lin - and CD44 - Lin - subpopulations were successfully isolated using fluorescence-activated cell sorting, and good-quality RNA was obtained from 14 such sorted pairs. Libraries from five pairs were sequenced and the results analysed using bioinformatics tools. Reverse transcription quantitative polymerase chain reaction was performed to experimentally validate the differential expression of selected candidate genes identified from the transcriptome sequencing in the same 5 and an additional 9 tumours. CD44 was expressed on the surface of poorly differentiated tumour cells, and within the The Cancer Genome Atlas-Head and Neck Squamous Cell Carcinoma samples, its messenger RNA levels were higher in tumours compared to normal. Transcriptomics revealed that 102 genes were upregulated and 85 genes were downregulated in CD44 + Lin - compared to CD44 - Lin - cells in at least 3 of the 5 tumours sequenced. The upregulated genes included those involved in immune regulation, while the downregulated genes were enriched for genes involved in cell adhesion. Decreased expression of PCDH18, MGP, SPARCL1 and KRTDAP was confirmed by reverse transcription quantitative polymerase chain reaction. Lower expression of

Expression of synaptogyrin-1 in T1R2-expressing type II taste cells and type III taste cells of rat circumvallate taste buds.

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Kotani, Takeshi; Toyono, Takashi; Seta, Yuji; Kitou, Ayae; Kataoka, Shinji; Toyoshima, Kuniaki

2013-09-01

Synaptogyrins are conserved components of the exocytic apparatus and function as regulators of Ca(2+)-dependent exocytosis. The synaptogyrin family comprises three isoforms: two neuronal (synaptogyrin-1 and -3) and one ubiquitous (synaptogyrin-2) form. Although the expression patterns of the exocytic proteins synaptotagmin-1, SNAP-25, synaptobrevin-2 and synaptophysin have been elucidated in taste buds, the function and expression pattern of synaptogyrin-1 in rat gustatory tissues have not been determined. Therefore, we examined the expression patterns of synaptogyrin-1 and several cell-specific markers of type II and III cells in rat gustatory tissues. Reverse transcription/polymerase chain reaction assays and immunoblot analysis revealed the expression of synaptogyrin-1 mRNA and its protein in circumvallate papillae. In fungiform, foliate and circumvallate papillae, the antibody against synaptogyrin-1 immunolabeled a subset of taste bud cells and intra- and subgemmal nerve processes. Double-labeling experiments revealed the expression of synaptogyrin-1 in most taste cells immunoreactive for aromatic L-amino acid decarboxylase and the neural cell adhesion molecule. A subset of synaptogyrin-1-immunoreactive taste cells also expressed phospholipase Cβ2, gustducin, or sweet taste receptor (T1R2). In addition, most synaptogyrin-1-immunoreactive taste cells expressed synaptobrevin-2. These results suggest that synaptogyrin-1 plays a regulatory role in transmission at the synapses of type III cells and is involved in exocytic function with synaptobrevin-2 in a subset of type II cells in rat taste buds.

Characterization of TLX expression in neural stem cells and progenitor cells in adult brains.

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Shengxiu Li

Full Text Available TLX has been shown to play an important role in regulating the self-renewal and proliferation of neural stem cells in adult brains. However, the cellular distribution of endogenous TLX protein in adult brains remains to be elucidated. In this study, we used immunostaining with a TLX-specific antibody to show that TLX is expressed in both neural stem cells and transit-amplifying neural progenitor cells in the subventricular zone (SVZ of adult mouse brains. Then, using a double thymidine analog labeling approach, we showed that almost all of the self-renewing neural stem cells expressed TLX. Interestingly, most of the TLX-positive cells in the SVZ represented the thymidine analog-negative, relatively quiescent neural stem cell population. Using cell type markers and short-term BrdU labeling, we demonstrated that TLX was also expressed in the Mash1+ rapidly dividing type C cells. Furthermore, loss of TLX expression dramatically reduced BrdU label-retaining neural stem cells and the actively dividing neural progenitor cells in the SVZ, but substantially increased GFAP staining and extended GFAP processes. These results suggest that TLX is essential to maintain the self-renewing neural stem cells in the SVZ and that the GFAP+ cells in the SVZ lose neural stem cell property upon loss of TLX expression. Understanding the cellular distribution of TLX and its function in specific cell types may provide insights into the development of therapeutic tools for neurodegenerative diseases by targeting TLX in neural stem/progenitors cells.

Amniotic Fluid Cells Show Higher Pluripotency-Related Gene Expression Than Allantoic Fluid Cells.

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Kehl, Debora; Generali, Melanie; Görtz, Sabrina; Geering, Diego; Slamecka, Jaroslav; Hoerstrup, Simon P; Bleul, Ulrich; Weber, Benedikt

2017-10-01

Amniotic fluid represents an abundant source of multipotent stem cells, referred as broadly multipotent given their differentiation potential and expression of pluripotency-related genes. However, the origin of this broadly multipotent cellular fraction is not fully understood. Several sources have been proposed so far, including embryonic and extraembryonic tissues. In this regard, the ovine developmental model uniquely allows for direct comparison of fetal fluid-derived cells from two separate fetal fluid cavities, the allantois and the amnion, over the entire duration of gestation. As allantoic fluid mainly collects fetal urine, cells originating from the efferent urinary tract can directly be compared with cells deriving from the extraembryonic amniotic tissues and the fetus. This study shows isolation of cells from the amniotic [ovine amniotic fluid cells (oAFCs)] and allantoic fluid [ovine allantoic fluid cells (oALCs)] in a strictly paired fashion with oAFCs and oALCs derived from the same fetus. Both cell types showed cellular phenotypes comparable to standard mesenchymal stem cells (MSCs), with trilineage differentiation potential, and expression of common ovine MSC markers. However, the expression of MSC markers per single cell was higher in oAFCs as measured by flow cytometry. oAFCs exhibited higher proliferative capacities and showed significantly higher expression of pluripotency-related genes OCT4, STAT3, NANOG, and REX1 by quantitative real-time polymerase chain reaction compared with paired oALCs. No significant decrease of pluripotency-related gene expression was noted over gestation, implying that cells with high differentiation potential may be isolated at the end of pregnancy. In conclusion, this study suggests that cells with highest stem cell characteristics may originate from the fetus itself or the amniotic fetal adnexa rather than from the efferent urinary tract or the allantoic fetal adnexa.

CD146 Expression Influences Periapical Cyst Mesenchymal Stem Cell Properties.

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Paduano, Francesco; Marrelli, Massimo; Palmieri, Francesca; Tatullo, Marco

2016-10-01

Recent studies have identified a new human dental derived progenitor cell population with multi-lineage differentiation potential referred to as human periapical cyst mesenchymal stem cells (hPCy-MSCs). In the present study, we compared two subpopulations of hPCy-MSCs characterised by the low or high expression of CD146 to establish whether this expression can regulate their stem cell properties. Using flow cytometry, we evaluated the stem cell marker profile of hPCy-MSCs during passaging. Furthermore, CD146 Low and CD146 High cells were sorted by magnetic beads and subsequently both cell populations were evaluated for differences in their proliferation, self-renewal, stem cell surface markers, stemness genes expression and osteogenic differentiation potential.We found that hPCy-MSCs possessed a stable expression of several mesenchymal stem cell surface markers, whereas CD146 expression declined during passaging.In addition, sorted CD146 Low cells proliferated significantly faster, displayed higher colony-forming unit-fibroblast capacity and showed higher expression of Klf4 when compared to the CD146 High subset. Significantly, the osteogenic potential of hPCy-MSCs was greater in the CD146 Low than in CD146 High population. These results demonstrate that CD146 is spontaneously downregulated with passaging at both mRNA and protein levels and that the high expression of CD146 reduces the proliferative, self-renewal and osteogenic differentiation potential of hPCy-MSCs. In conclusion, our study demonstrates that changes in the expression of CD146 can influence the stem cell properties of hPCy-MSCs.

CXCR3 surface expression in human airway epithelial cells: cell cycle dependence and effect on cell proliferation.

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Aksoy, Mark O; Yang, Yi; Ji, Rong; Reddy, P J; Shahabuddin, Syed; Litvin, Judith; Rogers, Thomas J; Kelsen, Steven G

2006-05-01

We recently demonstrated that human bronchial epithelial cells (HBEC) constitutively express the CXC chemokine receptor CXCR3, which when activated, induces directed cell migration. The present study in HBEC examined the relative expression of the CXCR3 splice variants CXCR3-A and -B, cell cycle dependence of CXCR3 expression, and the effects of the CXCR3 ligand, the interferon-gamma-inducible CXC chemokine I-TAC/CXCL11, on DNA synthesis and cell proliferation. Both CXCR3-A and -B mRNA, assessed by real-time RT-PCR, were expressed in normal HBEC (NHBEC) and the HBEC line 16-HBE. However, CXCR3-B mRNA was 39- and 6-fold greater than CXCR3-A mRNA in NHBEC and 16-HBE, respectively. Although most HBEC (>80%) assessed by flow cytometry and immunofluorescence microscopy contained intracellular CXCR3, only a minority (75%) were in the S + G(2)/M phases of the cell cycle. Stimulation of CXCR3 with I-TAC enhanced thymidine incorporation and cell proliferation and increased p38 and ERK1/2 phosphorylation. These data indicate that 1) human airway epithelial cells primarily express CXCR3-B mRNA, 2) surface expression of CXCR3 is largely confined to the S + G(2)/M phases of the cell cycle, and 3) activation of CXCR3 induces DNA synthesis, cell proliferation, and activation of MAPK pathways. We speculate that activation of CXCR3 exerts a mitogenic effect in HBEC, which may be important during airway mucosal injury in obstructive airway diseases such as asthma and chronic obstructive pulmonary disease.

Fractionated therapy of HER2-expressing breast and ovarian cancer xenografts in mice with targeted alpha emitting 227Th-DOTA-p-benzyl-trastuzumab.

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Helen Heyerdahl

Full Text Available BACKGROUND: The aim of this study was to investigate therapeutic efficacy and normal tissue toxicity of single dosage and fractionated targeted alpha therapy (TAT in mice with HER2-expressing breast and ovarian cancer xenografts using the low dose rate radioimmunoconjugate (227Th-DOTA-p-benzyl-trastuzumab. METHODOLOGY/PRINCIPAL FINDINGS: Nude mice carrying HER2-overexpressing subcutaneous SKOV-3 or SKBR-3 xenografts were treated with 1000 kBq/kg (227Th-trastuzumab as single injection or four injections of 250 kBq/kg with intervals of 4-5 days, 2 weeks, or 4 weeks. Control animals were treated with normal saline or unlabeled trastuzumab. In SKOV-3 xenografts tumor growth to 10-fold size was delayed (p<0.01 and survival with tumor diameter less than 16 mm was prolonged (p<0.05 in all TAT groups compared to the control groups. No statistically significant differences were seen among the treated groups. In SKBR-3 xenografts tumor growth to 10-fold size was delayed in the single injection and 4-5 days interval groups (p<0.001 and all except the 4 weeks interval TAT group showed improved survival to the control groups (p<0.05. Toxicity was assessed by blood cell counts, clinical chemistry measurements and body weight. Transient reduction in white blood cells was seen for the single injection and 4-5 days interval groups (p<0.05. No significant changes were seen in red blood cells, platelets or clinical chemistry parameters. Survival without life threatening loss of body weight was significantly prolonged in 4 weeks interval group compared to single injection group (p<0.05 for SKOV-3 animals and in 2 weeks interval group compared with the 4-5 days interval groups (p<0.05 for SKBR-3 animals. CONCLUSIONS/SIGNIFICANCE: The same concentration of radioactivity split into several fractions may improve toxicity of (227Th-radioimmunotherapy while the therapeutic effect is maintained. Thus, it might be possible to increase the cumulative absorbed radiation dose

Correlation of Slug gene expression with lymph node metastasis and invasion molecule expression in oral squamous cell carcinoma tissue

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Shan-Ming Lu

2017-10-01

Full Text Available Objective: To study the correlation of Slug gene expression with lymph node metastasis and invasion molecule expression in oral squamous cell carcinoma tissue. Methods: Oral squamous cell carcinoma tissue surgical removed in Affiliated Stomatological Hospital of Nanjing Medical University between March 2015 and April 2017 was selected and divided into the oral squamous cell carcinoma tissue with neck lymph node metastasis and the oral squamous cell carcinoma tissues without lymph node metastasis according to the condition of lymph node metastasis. The expression of Slug, epithelial-mesenchymal transition molecules and invasion molecules in the oral squamous cell carcinoma tissue were detected. Results: Slug, N-cadherin, Vimentin, CD147, OPN, GRP78, SDF-1 and CXCR4 protein expression in oral squamous cell carcinoma tissue with neck lymph node metastasis were significantly higher than those in oral squamous cell carcinoma tissue without lymph node metastasis while E-cadherin, P120ctn and ZO-1 protein expression were significantly lower than those in oral squamous cell carcinoma tissue without lymph node metastasis; N-cadherin, Vimentin, CD147, OPN, GRP78, SDF-1 and CXCR4 protein expression in oral squamous cell carcinoma tissue with high Slug expression were significantly higher than those in oral squamous cell carcinoma tissue with low Slug expression while E-cadherin, P120ctn and ZO-1 protein expression were significantly lower than those in oral squamous cell carcinoma tissue with low Slug expression. Conclusion: The highly expressed Slug in oral squamous cell carcinoma tissue can promote the epithelial-mesenchymal transition and invasion of the cells to participate in the lymph node metastasis of tumor cells.

The effect of the colostral cells on gene expression of cytokines in cord blood cells.

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Hrdý, Jiří; Novotná, Olga; Kocourková, Ingrid; Prokešová, Ludmila

2017-11-01

Beneficial effect of maternal milk is acknowledged, but there is still question whether maternal milk from allergic mother is as good as from healthy one. In our study, we have assayed the effect of cells from colostrum of healthy and allergic mothers on gene expression of cytokines in cord blood cells of newborns of healthy and allergic mothers. Cytokines typical for Th1 (IL-2, IFN-gamma), Th2 (IL-4, IL-13), Tregs (IL-10, TGF-beta), and IL-8 were followed. We were not able to detect significant influence of colostral cells on gene expression of cytokines in cord blood after 2-day coculture using Transwell system. There was no difference in gene expression of cytokines in nonstimulated cord blood cells of newborns of healthy and allergic mothers, but generally increased gene expression of cytokines except IL-10 and TGF-beta after polyclonal stimulation was detected in cord blood cells of children of allergic mothers. There was no difference in IL-10 expression in stimulated cord blood cells of children of healthy and allergic mothers. Gene expression of TGF-beta was even decreased in stimulated cord blood cells of children of allergic mothers in comparison to healthy ones. We have not observed difference in the capacity of colostral cells of healthy and allergic mothers to influence gene expression of cytokines in cord blood cells, but we have described difference in the reactivity of cord blood cells between children of allergic and healthy mothers.

UV-induced changes in cell cycle and gene expression within rabbit lens epithelial cells

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Sidjanin, D. [Northern Illinois Univ., De Kalb, IL (United States). Dept. of Biological Sciences; Grdina, D. [Argonne National Lab., IL (United States); Woloschak, G.E. [Northern Illinois Univ., De Kalb, IL (United States). Dept. of Biological Sciences

1994-11-01

Damage to lens epithelial cells is a probable initiation process in cataract formation induced by ultraviolet radiation. These experiments investigated the ability of 254 nm radiation on cell cycle progression and gene expression in rabbit lens epithelial cell line N/N1003A. No changes in expression of c-fos, c-jun, alpha- tubulin, or vimentin was observed following UV exposure. Using flow cytometry, an accumulation of cells in G1/S phase of the cell cycle 1 hr following exposure. The observed changes in gene expression, especially the decreased histone transcripts reported here may play a role in UV induced inhibition of cell cycle progression.

Gene expression analysis of embryonic stem cells expressing VE-cadherin (CD144 during endothelial differentiation

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Libermann Towia

2008-05-01

Full Text Available Abstract Background Endothelial differentiation occurs during normal vascular development in the developing embryo. This process is recapitulated in the adult when endothelial progenitor cells are generated in the bone marrow and can contribute to vascular repair or angiogenesis at sites of vascular injury or ischemia. The molecular mechanisms of endothelial differentiation remain incompletely understood. Novel approaches are needed to identify the factors that regulate endothelial differentiation. Methods Mouse embryonic stem (ES cells were used to further define the molecular mechanisms of endothelial differentiation. By flow cytometry a population of VEGF-R2 positive cells was identified as early as 2.5 days after differentiation of ES cells, and a subset of VEGF-R2+ cells, that were CD41 positive at 3.5 days. A separate population of VEGF-R2+ stem cells expressing the endothelial-specific marker CD144 (VE-cadherin was also identified at this same time point. Channels lined by VE-cadherin positive cells developed within the embryoid bodies (EBs formed by differentiating ES cells. VE-cadherin and CD41 expressing cells differentiate in close proximity to each other within the EBs, supporting the concept of a common origin for cells of hematopoietic and endothelial lineages. Results Microarray analysis of >45,000 transcripts was performed on RNA obtained from cells expressing VEGF-R2+, CD41+, and CD144+ and VEGF-R2-, CD41-, and CD144-. All microarray experiments were performed in duplicate using RNA obtained from independent experiments, for each subset of cells. Expression profiling confirmed the role of several genes involved in hematopoiesis, and identified several putative genes involved in endothelial differentiation. Conclusion The isolation of CD144+ cells during ES cell differentiation from embryoid bodies provides an excellent model system and method for identifying genes that are expressed during endothelial differentiation and that

Murine cell glycolipids customization by modular expression of glycosyltransferases.

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Cid, Emili; Yamamoto, Miyako; Buschbeck, Marcus; Yamamoto, Fumiichiro

2013-01-01

Functional analysis of glycolipids has been hampered by their complex nature and combinatorial expression in cells and tissues. We report an efficient and easy method to generate cells with specific glycolipids. In our proof of principle experiments we have demonstrated the customized expression of two relevant glycosphingolipids on murine fibroblasts, stage-specific embryonic antigen 3 (SSEA-3), a marker for stem cells, and Forssman glycolipid, a xenoantigen. Sets of genes encoding glycosyltansferases were transduced by viral infection followed by multi-color cell sorting based on coupled expression of fluorescent proteins.

Expression of uncoupling protein 1 in bovine muscle cells.

Science.gov (United States)

Abd Eldaim, M A; Hashimoto, O; Ohtsuki, H; Yamada, T; Murakami, M; Onda, K; Sato, R; Kanamori, Y; Qiao, Y; Tomonaga, S; Matsui, T; Funaba, M

2016-12-01

Uncoupling protein 1 (Ucp1) is predominantly expressed in brown/beige adipocytes in mammals. Although myogenic cells have been suggested to commit to a brown adipocyte lineage through the induction of Prdm16 expression, Prdm16 is also expressed in skeletal muscle. Thus, we examined expression of Ucp1 in bovine myogenic cells. Considering that Ucp1 is a principle molecule that induces energy expenditure in brown/beige adipocytes, expression of Ucp1 is not preferable in beef cattle because of potential decrease in energy (fattening) efficiency. The RT-PCR analyses revealed the expression of Ucp1 in the skeletal muscle of cattle; expression levels were markedly lower than those in the brown fat of calves. Immunohistochemical analyses showed that Ucp1 surrounded muscle fibers, but not adipocytes residing in skeletal muscle. Myosatellite cells cultured in myogenic medium showed an increase in the expression levels of myogenic regulatory factors ( levels were greater in cells after myogenic culture for 12 d than in those after myogenic culture for 6 d ( bovine skeletal muscle, which suggests the necessity for further studies on Ucp1-mediated energy expenditure in bovine skeletal muscle.

T-Cadherin Expression in Melanoma Cells Stimulates Stromal Cell Recruitment and Invasion by Regulating the Expression of Chemokines, Integrins and Adhesion Molecules

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Rubina, Kseniya A.; Surkova, Ekaterina I.; Semina, Ekaterina V.; Sysoeva, Veronika Y.; Kalinina, Natalia I.; Poliakov, Alexei A.; Treshalina, Helena M.; Tkachuk, Vsevolod A.

2015-01-01

T-cadherin is a glycosyl-phosphatidylinositol (GPI) anchored member of the cadherin superfamily involved in the guidance of migrating cells. We have previously shown that in vivo T-cadherin overexpression leads to increased melanoma primary tumor growth due to the recruitment of mesenchymal stromal cells as well as the enhanced metastasis. Since tumor progression is highly dependent upon cell migration and invasion, the aim of the present study was to elucidate the mechanisms of T-cadherin participation in these processes. Herein we show that T-cadherin expression results in the increased invasive potential due to the upregulated expression of pro-oncogenic integrins, chemokines, adhesion molecules and extracellular matrix components. The detected increase in chemokine expression could be responsible for the stromal cell recruitment. At the same time our previous data demonstrated that T-cadherin expression inhibited neoangiogenesis in the primary tumors. We demonstrate that T-cadherin overexpression leads to the increase in the expression of anti-angiogenic molecules and reduction in pro-angiogenic factors. Thus, T-cadherin plays a dual role in melanoma growth and progression: T-cadherin expression results in anti-angiogenic effects in melanoma, however, this also stimulates transcription of genes responsible for migration and invasion of melanoma cells

T-Cadherin Expression in Melanoma Cells Stimulates Stromal Cell Recruitment and Invasion by Regulating the Expression of Chemokines, Integrins and Adhesion Molecules

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Rubina, Kseniya A., E-mail: rkseniya@mail.ru; Surkova, Ekaterina I.; Semina, Ekaterina V.; Sysoeva, Veronika Y.; Kalinina, Natalia I. [Department of Biochemistry and Molecular Medicine, Faculty of Medicine, M.V. Lomonosov Moscow State University, Lomonosovsky av., 31/5, Moscow 119192 (Russian Federation); Poliakov, Alexei A. [Division of Developmental Neurobiology, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA (United Kingdom); Treshalina, Helena M. [Federal State Budgetary Scietific Institution «N.N. Blokhin Russian Cancer Research Center» (FSBSI “N.N.Blokhin RCRC”), Kashirskoe Shosse 24, Moscow 115478 (Russian Federation); Tkachuk, Vsevolod A. [Department of Biochemistry and Molecular Medicine, Faculty of Medicine, M.V. Lomonosov Moscow State University, Lomonosovsky av., 31/5, Moscow 119192 (Russian Federation)

2015-07-21

T-cadherin is a glycosyl-phosphatidylinositol (GPI) anchored member of the cadherin superfamily involved in the guidance of migrating cells. We have previously shown that in vivo T-cadherin overexpression leads to increased melanoma primary tumor growth due to the recruitment of mesenchymal stromal cells as well as the enhanced metastasis. Since tumor progression is highly dependent upon cell migration and invasion, the aim of the present study was to elucidate the mechanisms of T-cadherin participation in these processes. Herein we show that T-cadherin expression results in the increased invasive potential due to the upregulated expression of pro-oncogenic integrins, chemokines, adhesion molecules and extracellular matrix components. The detected increase in chemokine expression could be responsible for the stromal cell recruitment. At the same time our previous data demonstrated that T-cadherin expression inhibited neoangiogenesis in the primary tumors. We demonstrate that T-cadherin overexpression leads to the increase in the expression of anti-angiogenic molecules and reduction in pro-angiogenic factors. Thus, T-cadherin plays a dual role in melanoma growth and progression: T-cadherin expression results in anti-angiogenic effects in melanoma, however, this also stimulates transcription of genes responsible for migration and invasion of melanoma cells.

Analysis of allelic expression patterns in clonal somatic cells by single-cell RNA-seq.

Science.gov (United States)

Reinius, Björn; Mold, Jeff E; Ramsköld, Daniel; Deng, Qiaolin; Johnsson, Per; Michaëlsson, Jakob; Frisén, Jonas; Sandberg, Rickard

2016-11-01

Cellular heterogeneity can emerge from the expression of only one parental allele. However, it has remained controversial whether, or to what degree, random monoallelic expression of autosomal genes (aRME) is mitotically inherited (clonal) or stochastic (dynamic) in somatic cells, particularly in vivo. Here we used allele-sensitive single-cell RNA-seq on clonal primary mouse fibroblasts and freshly isolated human CD8 + T cells to dissect clonal and dynamic monoallelic expression patterns. Dynamic aRME affected a considerable portion of the cells' transcriptomes, with levels dependent on the cells' transcriptional activity. Notably, clonal aRME was detected, but it was surprisingly scarce (aRME occurs transiently within individual cells, and patterns of aRME are thus primarily scattered throughout somatic cell populations rather than, as previously hypothesized, confined to patches of clonally related cells.

Multi-functional system of radiotherapy and thermal phototherapy for tumors that over-express receptors of the gastrin releasing peptide; Sistema multifuncional de radioterapia y fototerapia termica para tumores que sobre-expresan receptores del peptido liberador de gastrina

Energy Technology Data Exchange (ETDEWEB)

Jimenez M, N. P.

2014-07-01

the -Sh groups. The radiochemical purity was 96 ± 2%, no further purification was necessary. In vitro studies showed that after laser irradiation, the presence of AuNP-Tat-Bn caused a significant increase in the temperature of the medium (46.4 grades C vs. 39.5 grades C of that without AuNP) resulting in a significant decrease in PC3 cell viability down to 1.3 %. In the in vivo studies the {sup 177}Lu/{sup 99m}Tc-AuNP-Tat-Bn showed a biological residence time of 80.6 h. The radiation absorbed doses from {sup 177}Lu and {sup 99m}Tc to the tumor after normalization to the unit of administered activity were 7.90 ± 0.95 Gy/MBq and 0.07±0.01 Gy/MBq, respectively. Fluorescent images showed that the system was internalized into the nucleus of PC3 cells. The {sup 177}Lu/{sup 99m}Tc-AuNP-Tat-Bn system showed properties suitable for a targeted radionuclide therapy of tumours expressing GRP receptors due to the energy deposition from β-emissions and the Auger and internal conversion electron emissions near the DNA. It has potential application in medical diagnosis and therapeutic treatments due to its unique combination of radioactive, optical and thermo ablative properties, therefore, this study demonstrated that the nano system exhibited properties that are suitable for plasmonic photothermal therapy and targeted radiotherapy in the treatment of prostate cancer. (Author)

A novel strategy to activate cytoprotective genes in the injured brain

International Nuclear Information System (INIS)

Zhao, Jing; Redell, John B.; Moore, Anthony N.; Dash, Pramod K.

2011-01-01

Highlights: → A strategy to increase cytoprotective gene expression in injured tissue is outlined. → A peptide containing a DEETGE motif can increase Nrf2 responsive genes in vivo. → Gene expression in injured brains requires a calpain cleavage site. → This peptide decreases BBB compromise when infused pre- or post-brain injury. → Cleavage sites for disease-specific proteases could be used to treat that condition. -- Abstract: The transcription factor nuclear factor E2-related factor 2 (Nrf2) regulates the expression of multiple cytoprotective genes that have been shown to offer protection in response to a number of insults. The present study describes a novel strategy to increase expression of Nrf2-responsive genes in brain injured mice. Under normal conditions, the adapter protein Kelch-like ECH-associated protein 1 (Keap1) binds to Nrf2 and promotes its proteosomal degradation in the cytoplasm. The amino acid sequence DEETGE, located at amino acid 77-82 of Nrf2, is critical for Nrf2-Keap1 interaction, and synthetic peptides containing this sequence can be used to disrupt the complex in vitro. We observed that intracerebroventricular (i.c.v.) infusion of a peptide containing the DEETGE sequence along with the cell transduction domain of the HIV-TAT protein (TAT-DEETGE) into brain-injured mice did not increase the mRNA levels for Nrf2-driven genes. However, when a calpain cleavage sequence was introduced between the TAT sequence and the DEETGE sequence, the new peptide (TAT-CAL-DEETGE) increased the mRNA levels of these genes. Increased gene expression was not observed when the TAT-CAL-DEETGE peptide was injected into uninjured animals. Furthermore, injection of TAT-CAL-DEETGE peptides before or after brain injury reduced blood-brain barrier compromise, a prominent secondary pathology that negatively influences outcome. The present strategy to increase Nrf2-responsive gene expression can be adapted to treat other insults or diseases based on their

High expression of markers of apoptosis in Langerhans cell histiocytosis

DEFF Research Database (Denmark)

Petersen, Bodil Laub; Lundegaard, Pia Rengtved; Bank, M I

2003-01-01

53 and the number of cells in apoptosis detected with TUNEL. Langerhans cell histiocytosis cells showed strong expression of p53 and in some cases co-expression of Fas and Fas-L. The expression of Fas-L was significantly higher in infiltrates from patients with single-system disease. The actual...... number of pathological Langerhans cells in apoptosis as estimated by TUNEL was low. CONCLUSIONS: The low number of TUNEL-reactive cells can be explained by the rapid turnover of apoptotic cells in the tissue, not leaving the apoptotic cells long enough in the tissue to be detected. The co......-expression of Fas and Fas-L in some Langerhans cells can lead to an autocrine apoptotic shortcut, mediating the death of the double-positive cells. Our findings suggest that apoptosis mediated through the Fas/Fas-L pathway may contribute to the spontaneous regression of lesions in single-system disease. A delicate...

Ectopic ERK Expression Induces Phenotypic Conversion of C10 Cells and Alters DNA Methyltransferase Expression

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Sontag, Ryan L.; Weber, Thomas J.

2012-05-04

In some model systems constitutive extracellular signal regulated kinase (ERK) activation is sufficient to promote an oncogenic phenotype. Here we investigate whether constitutive ERK expression influences phenotypic conversion in murine C10 type II alveolar epithelial cells. C10 cells were stably transduced with an ERK1-green fluorescent protein (ERK1-GFP) chimera or empty vector and ectopic ERK expression was associated with the acquisition of soft agar focus-forming potential in late passage, but not early passage cells. Late passage ERK1-GFP cells exhibited a significant increase in the expression of DNA methyl transferases (DNMT1 and 3b) and a marked increase in sensitivity to 5-azacytidine (5-azaC)-mediated toxicity, relative to early passage ERK1-GFP cells and vector controls. The expression of xeroderma pigmentosum complementation group A (XPA) and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) were significantly increased in late passage cells, suggesting enhanced DNA damage recognition and repair activity which we interpret as a reflection of genomic instability. Phospho-ERK levels were dramatically decreased in late passage ERK1-GFP cells, relative to early passage and vector controls, and phospho-ERK levels were restored by treatment with sodium orthovanadate, indicating a role for phosphatase activity in this response. Collectively these observations suggest that ectopic ERK expression promotes phenotypic conversion of C10 cells that is associated with latent effects on epigenetic programming and phosphatase activities.

Freedom of expression: cell-type-specific gene profiling.

Science.gov (United States)

Otsuki, Leo; Cheetham, Seth W; Brand, Andrea H

2014-01-01

Cell fate and behavior are results of differential gene regulation, making techniques to profile gene expression in specific cell types highly desirable. Many methods now enable investigation at the DNA, RNA and protein level. This review introduces the most recent and popular techniques, and discusses key issues influencing the choice between these such as ease, cost and applicability of information gained. Interdisciplinary collaborations will no doubt contribute further advances, including not just in single cell type but single-cell expression profiling. © 2014 Wiley Periodicals, Inc.

Docosahexaenoic acid inhibits IL-6 expression via PPARγ-mediated expression of catalase in cerulein-stimulated pancreatic acinar cells.

Science.gov (United States)

Song, Eun Ah; Lim, Joo Weon; Kim, Hyeyoung

2017-07-01

Cerulein pancreatitis mirrors human acute pancreatitis. In pancreatic acinar cells exposed to cerulein, reactive oxygen species (ROS) mediate inflammatory signaling by Janus kinase (JAK) 2/signal transducer and activator of transcription (STAT) 3, and cytokine induction. Docosahexaenoic acid (DHA) acts as an agonist of peroxisome proliferator activated receptor γ (PPARγ), which mediates the expression of some antioxidant enzymes. We hypothesized that DHA may induce PPARγ-target catalase expression and reduce ROS levels, leading to the inhibition of JAK2/STAT3 activation and IL-6 expression in cerulein-stimulated acinar cells. Pancreatic acinar AR42J cells were treated with DHA in the presence or absence of the PPARγ antagonist GW9662, or treated with the PPARγ agonist troglitazone, and then stimulated with cerulein. Expression of IL-6 and catalase, ROS levels, JAK2/STAT3 activation, and nuclear translocation of PPARγ were assessed. DHA suppressed the increase in ROS, JAK2/STAT3 activation, and IL-6 expression induced nuclear translocation of PPARγ and catalase expression in cerulein-stimulated AR42J cells. Troglitazone inhibited the cerulein-induced increase in ROS and IL-6 expression, but induced catalase expression similar to DHA in AR42J cells. GW9662 abolished the inhibitory effect of DHA on cerulein-induced increase in ROS and IL-6 expression in AR42J cells. DHA-induced expression of catalase was suppressed by GW9662 in cerulein-stimulated AR42J cells. Thus, DHA induces PPARγ activation and catalase expression, which inhibits ROS-mediated activation of JAK2/STAT3 and IL-6 expression in cerulein-stimulated pancreatic acinar cells. Copyright © 2017. Published by Elsevier Ltd.

Cell adhesion signaling regulates RANK expression in osteoclast precursors.

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Ayako Mochizuki

Full Text Available Cells with monocyte/macrophage lineage expressing receptor activator of NF-κB (RANK differentiate into osteoclasts following stimulation with the RANK ligand (RANKL. Cell adhesion signaling is also required for osteoclast differentiation from precursors. However, details of the mechanism by which cell adhesion signals induce osteoclast differentiation have not been fully elucidated. To investigate the participation of cell adhesion signaling in osteoclast differentiation, mouse bone marrow-derived macrophages (BMMs were used as osteoclast precursors, and cultured on either plastic cell culture dishes (adherent condition or the top surface of semisolid methylcellulose gel loaded in culture tubes (non-adherent condition. BMMs cultured under the adherent condition differentiated into osteoclasts in response to RANKL stimulation. However, under the non-adherent condition, the efficiency of osteoclast differentiation was markedly reduced even in the presence of RANKL. These BMMs retained macrophage characteristics including phagocytic function and gene expression profile. Lipopolysaccharide (LPS and tumor necrosis factor -αTNF-α activated the NF-κB-mediated signaling pathways under both the adherent and non-adherent conditions, while RANKL activated the pathways only under the adherent condition. BMMs highly expressed RANK mRNA and protein under the adherent condition as compared to the non-adherent condition. Also, BMMs transferred from the adherent to non-adherent condition showed downregulated RANK expression within 24 hours. In contrast, transferring those from the non-adherent to adherent condition significantly increased the level of RANK expression. Moreover, interruption of cell adhesion signaling by echistatin, an RGD-containing disintegrin, decreased RANK expression in BMMs, while forced expression of either RANK or TNFR-associated factor 6 (TRAF6 in BMMs induced their differentiation into osteoclasts even under the non

'Fluorescent Cell Chip' for immunotoxicity testing: Development of the c-fos expression reporter cell lines

International Nuclear Information System (INIS)

Trzaska, Dominika; Zembek, Patrycja; Olszewski, Maciej; Adamczewska, Violetta; Ulleras, Erik; Dastych, JarosIaw

2005-01-01

The Fluorescent Cell Chip for in vitro immunotoxicity testing employs cell lines derived from lymphocytes, mast cells, and monocytes-macrophages transfected with various EGFP cytokine reporter gene constructs. While cytokine expression is a valid endpoint for in vitro immunotoxicity screening, additional marker for the immediate-early response gene expression level could be of interest for further development and refinement of the Fluorescent Cell Chip. We have used BW.5147.3 murine thymoma transfected with c-fos reporter constructs to obtain reporter cell lines expressing ECFP under the control of murine c-fos promoter. These cells upon serum withdrawal and readdition and incubation with heavy metal compounds showed paralleled induction of c-Fos expression as evidenced by Real-Time PCR and ECFP fluorescence as evidenced by computer-supported fluorescence microscopy. In conclusion, we developed fluorescent reporter cell lines that could be employed in a simple and time-efficient screening assay for possible action of chemicals on c-Fos expression in lymphocytes. The evaluation of usefulness of these cells for the Fluorescent Cell Chip-based detection of immunotoxicity will require additional testing with a larger number of chemicals

Production of pancreatic hormone-expressing endocrine cells from human embryonic stem cells.

Science.gov (United States)

D'Amour, Kevin A; Bang, Anne G; Eliazer, Susan; Kelly, Olivia G; Agulnick, Alan D; Smart, Nora G; Moorman, Mark A; Kroon, Evert; Carpenter, Melissa K; Baetge, Emmanuel E

2006-11-01

Of paramount importance for the development of cell therapies to treat diabetes is the production of sufficient numbers of pancreatic endocrine cells that function similarly to primary islets. We have developed a differentiation process that converts human embryonic stem (hES) cells to endocrine cells capable of synthesizing the pancreatic hormones insulin, glucagon, somatostatin, pancreatic polypeptide and ghrelin. This process mimics in vivo pancreatic organogenesis by directing cells through stages resembling definitive endoderm, gut-tube endoderm, pancreatic endoderm and endocrine precursor--en route to cells that express endocrine hormones. The hES cell-derived insulin-expressing cells have an insulin content approaching that of adult islets. Similar to fetal beta-cells, they release C-peptide in response to multiple secretory stimuli, but only minimally to glucose. Production of these hES cell-derived endocrine cells may represent a critical step in the development of a renewable source of cells for diabetes cell therapy.

Differential expression of the klf6 tumor suppressor gene upon cell damaging treatments in cancer cells

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Gehrau, Ricardo C.; D' Astolfo, Diego S.; Andreoli, Veronica [Centro de Investigaciones en Bioquimica Clinica e Inmunologia (CIBICI-CONICET), Departamento de Bioquimica Clinica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina); Bocco, Jose L., E-mail: jbocco@fcq.unc.edu.ar [Centro de Investigaciones en Bioquimica Clinica e Inmunologia (CIBICI-CONICET), Departamento de Bioquimica Clinica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina); Koritschoner, Nicolas P. [Centro de Investigaciones en Bioquimica Clinica e Inmunologia (CIBICI-CONICET), Departamento de Bioquimica Clinica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina)

2011-02-10

The mammalian Krueppel-like factor 6 (KLF6) is involved in critical roles such as growth-related signal transduction, cell proliferation and differentiation, development, apoptosis and angiogenesis. Also, KLF6 appears to be an emerging key factor during cancer development and progression. Its expression is thoroughly regulated by several cell-damaging stimuli. DNA damaging agents at lethal concentrations induce a p53-independent down-regulation of the klf6 gene. To investigate the impact of external stimuli on human klf6 gene expression, its mRNA level was analyzed using a cancer cell line profiling array system, consisting in an assortment of immobilized cDNAs from multiple cell lines treated with several cell-damaging agents at growth inhibitory concentrations (IC{sub 50}). Cell-damaging agents affected the klf6 expression in 62% of the cDNA samples, though the expression pattern was not dependent on the cell origin type. Interestingly, significant differences (p < 0.0001) in KLF6 mRNA levels were observed depending on the cellular p53 status upon cell damage. KLF6 expression was significantly increased in 63% of p53-deficient cells (122/195). Conversely, KLF6 mRNA level decreased nearly 4 fold in more than 70% of p53+/+ cells. In addition, klf6 gene promoter activity was down-regulated by DNA damaging agents in cells expressing the functional p53 protein whereas it was moderately increased in the absence of functional p53. Consistent results were obtained for the endogenous KLF6 protein level. Results indicate that human klf6 gene expression is responsive to external cell damage mediated by IC{sub 50} concentrations of physical and chemical stimuli in a p53-dependent manner. Most of these agents are frequently used in cancer therapy. Induction of klf6 expression in the absence of functional p53 directly correlates with cell death triggered by these compounds, whereas it is down-regulated in p53+/+ cells. Hence, klf6 expression level could represent a valuable

T-Cadherin Expression in Melanoma Cells Stimulates Stromal Cell Recruitment and Invasion by Regulating the Expression of Chemokines, Integrins and Adhesion Molecules

Directory of Open Access Journals (Sweden)

Kseniya A. Rubina

2015-07-01

Full Text Available T-cadherin is a glycosyl-phosphatidylinositol (GPI anchored member of the cadherin superfamily involved in the guidance of migrating cells. We have previously shown that in vivo T-cadherin overexpression leads to increased melanoma primary tumor growth due to the recruitment of mesenchymal stromal cells as well as the enhanced metastasis. Since tumor progression is highly dependent upon cell migration and invasion, the aim of the present study was to elucidate the mechanisms of T-cadherin participation in these processes. Herein we show that T-cadherin expression results in the increased invasive potential due to the upregulated expression of pro-oncogenic integrins, chemokines, adhesion molecules and extracellular matrix components. The detected increase in chemokine expression could be responsible for the stromal cell recruitment. At the same time our previous data demonstrated that T-cadherin expression inhibited neoangiogenesis in the primary tumors. We demonstrate molecules and reduction in pro-angiogenic factors. Thus, T-cadherin plays a dual role in melanoma growth and progression: T-cadherin expression results in anti-angiogenic effects in melanoma, however, this also stimulates transcription of genes responsible for migration and invasion of melanoma cells.

Src Induces Podoplanin Expression to Promote Cell Migration*

Science.gov (United States)

Shen, Yongquan; Chen, Chen-Shan; Ichikawa, Hitoshi; Goldberg, Gary S.

2010-01-01

Nontransformed cells can force tumor cells to assume a normal morphology and phenotype by the process of contact normalization. Transformed cells must escape this process to become invasive and malignant. However, mechanisms underlying contact normalization have not been elucidated. Here, we have identified genes that are affected by contact normalization of Src-transformed cells. Tumor cells must migrate to become invasive and malignant. Src must phosphorylate the adaptor protein Cas (Crk-associated substrate) to promote tumor cell motility. We report here that Src utilizes Cas to induce podoplanin (Pdpn) expression to promote tumor cell migration. Pdpn is a membrane-bound extracellular glycoprotein that associates with endogenous ligands to promote tumor cell migration leading to cancer invasion and metastasis. In fact, Pdpn expression accounted for a major part of the increased migration seen in Src-transformed cells. Moreover, nontransformed cells suppressed Pdpn expression in adjacent Src-transformed cells. Of >39,000 genes, Pdpn was one of only 23 genes found to be induced by transforming Src activity and suppressed by contact normalization of Src-transformed cells. In addition, we found 16 genes suppressed by Src and induced by contact normalization. These genes encode growth factor receptors, adaptor proteins, and products that have not yet been annotated and may play important roles in tumor cell growth and migration. PMID:20123990

Expression of GABAergic receptors in mouse taste receptor cells.

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Margaret R Starostik

Full Text Available BACKGROUND: Multiple excitatory neurotransmitters have been identified in the mammalian taste transduction, with few studies focused on inhibitory neurotransmitters. Since the synthetic enzyme glutamate decarboxylase (GAD for gamma-aminobutyric acid (GABA is expressed in a subset of mouse taste cells, we hypothesized that other components of the GABA signaling pathway are likely expressed in this system. GABA signaling is initiated by the activation of either ionotropic receptors (GABA(A and GABA(C or metabotropic receptors (GABA(B while it is terminated by the re-uptake of GABA through transporters (GATs. METHODOLOGY/PRINCIPAL FINDINGS: Using reverse transcriptase-PCR (RT-PCR analysis, we investigated the expression of different GABA signaling molecules in the mouse taste system. Taste receptor cells (TRCs in the circumvallate papillae express multiple subunits of the GABA(A and GABA(B receptors as well as multiple GATs. Immunocytochemical analyses examined the distribution of the GABA machinery in the circumvallate papillae. Both GABA(A-and GABA(B- immunoreactivity were detected in the peripheral taste receptor cells. We also used transgenic mice that express green fluorescent protein (GFP in either the Type II taste cells, which can respond to bitter, sweet or umami taste stimuli, or in the Type III GAD67 expressing taste cells. Thus, we were able to identify that GABAergic receptors are expressed in some Type II and Type III taste cells. Mouse GAT4 labeling was concentrated in the cells surrounding the taste buds with a few positively labeled TRCs at the margins of the taste buds. CONCLUSIONS/SIGNIFICANCE: The presence of GABAergic receptors localized on Type II and Type III taste cells suggests that GABA is likely modulating evoked taste responses in the mouse taste bud.

Lineage relationship of prostate cancer cell types based on gene expression

Directory of Open Access Journals (Sweden)

Ware Carol B

2011-05-01

Full Text Available Abstract Background Prostate tumor heterogeneity is a major factor in disease management. Heterogeneity could be due to multiple cancer cell types with distinct gene expression. Of clinical importance is the so-called cancer stem cell type. Cell type-specific transcriptomes are used to examine lineage relationship among cancer cell types and their expression similarity to normal cell types including stem/progenitor cells. Methods Transcriptomes were determined by Affymetrix DNA array analysis for the following cell types. Putative prostate progenitor cell populations were characterized and isolated by expression of the membrane transporter ABCG2. Stem cells were represented by embryonic stem and embryonal carcinoma cells. The cancer cell types were Gleason pattern 3 (glandular histomorphology and pattern 4 (aglandular sorted from primary tumors, cultured prostate cancer cell lines originally established from metastatic lesions, xenografts LuCaP 35 (adenocarcinoma phenotype and LuCaP 49 (neuroendocrine/small cell carcinoma grown in mice. No detectable gene expression differences were detected among serial passages of the LuCaP xenografts. Results Based on transcriptomes, the different cancer cell types could be clustered into a luminal-like grouping and a non-luminal-like (also not basal-like grouping. The non-luminal-like types showed expression more similar to that of stem/progenitor cells than the luminal-like types. However, none showed expression of stem cell genes known to maintain stemness. Conclusions Non-luminal-like types are all representatives of aggressive disease, and this could be attributed to the similarity in overall gene expression to stem and progenitor cell types.

Reduced Ang2 expression in aging endothelial cells

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Hohensinner, P.J.; Ebenbauer, B.; Kaun, C.; Maurer, G.; Huber, K.; Wojta, J.

2016-01-01

Aging endothelial cells are characterized by increased cell size, reduced telomere length and increased expression of proinflammatory cytokines. In addition, we describe here that aging reduces the migratory distance of endothelial cells. Furthermore, we observe an increase of the quiescence protein Ang1 and a decrease of the endothelial activation protein Ang2 upon aging. Supplementing Ang2 to aged endothelial cells restored their migratory capacity. We conclude that aging shifts the balance of the Ang1/Ang2 network favouring a quiescent state. Activation of endothelial cells in aging might be necessary to enhance wound healing capacities. -- Highlights: •Endothelial cells display signs of aging before reaching proliferative senescence. •Aging endothelial cells express more angiopoietin 1 and less angiopoietin 2 than young endothelial cells. •Migratory capacity is reduced in aging endothelial cells.

Reduced Ang2 expression in aging endothelial cells

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Hohensinner, P.J., E-mail: philipp.hohensinner@meduniwien.ac.at [Department of Internal Medicine II, Medical University of Vienna, Vienna (Austria); Ebenbauer, B. [Department of Internal Medicine II, Medical University of Vienna, Vienna (Austria); Ludwig Boltzmann Cluster for Cardiovascular Research, Vienna (Austria); Kaun, C.; Maurer, G. [Department of Internal Medicine II, Medical University of Vienna, Vienna (Austria); Huber, K. [Ludwig Boltzmann Cluster for Cardiovascular Research, Vienna (Austria); 3rd Medical Department, Wilhelminenhospital, Vienna (Austria); Sigmund Freud University, Medical Faculty, Vienna (Austria); Wojta, J. [Department of Internal Medicine II, Medical University of Vienna, Vienna (Austria); Ludwig Boltzmann Cluster for Cardiovascular Research, Vienna (Austria); Core Facilities, Medical University of Vienna, Vienna (Austria)

2016-06-03

Aging endothelial cells are characterized by increased cell size, reduced telomere length and increased expression of proinflammatory cytokines. In addition, we describe here that aging reduces the migratory distance of endothelial cells. Furthermore, we observe an increase of the quiescence protein Ang1 and a decrease of the endothelial activation protein Ang2 upon aging. Supplementing Ang2 to aged endothelial cells restored their migratory capacity. We conclude that aging shifts the balance of the Ang1/Ang2 network favouring a quiescent state. Activation of endothelial cells in aging might be necessary to enhance wound healing capacities. -- Highlights: •Endothelial cells display signs of aging before reaching proliferative senescence. •Aging endothelial cells express more angiopoietin 1 and less angiopoietin 2 than young endothelial cells. •Migratory capacity is reduced in aging endothelial cells.

Increasing RpoS expression causes cell death in Borrelia burgdorferi.

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Linxu Chen

Full Text Available RpoS, one of the two alternative σ factors in Borrelia burgdorferi, is tightly controlled by multiple regulators and, in turn, determines expression of many critical virulence factors. Here we show that increasing RpoS expression causes cell death. The immediate effect of increasing RpoS expression was to promote bacterial division and as a consequence result in a rapid increase in cell number before causing bacterial death. No DNA fragmentation or degradation was observed during this induced cell death. Cryo-electron microscopy showed induced cells first formed blebs, which were eventually released from dying cells. Apparently blebbing initiated cell disintegration leading to cell death. These findings led us to hypothesize that increasing RpoS expression triggers intracellular programs and/or pathways that cause spirochete death. The potential biological significance of induced cell death may help B. burgdorferi regulate its population to maintain its life cycle in nature.

Chemokine receptor expression by inflammatory T cells in EAE

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Mony, Jyothi Thyagabhavan; Khorooshi, Reza; Owens, Trevor

2014-01-01

Chemokines direct cellular infiltration to tissues, and their receptors and signaling pathways represent targets for therapy in diseases such as multiple sclerosis (MS). The chemokine CCL20 is expressed in choroid plexus, a site of entry of T cells to the central nervous system (CNS). The CCL20...... receptor CCR6 has been reported to be selectively expressed by CD4(+) T cells that produce the cytokine IL-17 (Th17 cells). Th17 cells and interferon-gamma (IFNγ)-producing Th1 cells are implicated in induction of MS and its animal model experimental autoimmune encephalomyelitis (EAE). We have assessed...... whether CCR6 identifies specific inflammatory T cell subsets in EAE. Our approach was to induce EAE, and then examine chemokine receptor expression by cytokine-producing T cells sorted from CNS at peak disease. About 7% of CNS-infiltrating CD4(+) T cells produced IFNγ in flow cytometric cytokine assays...

Dissecting stem cell differentiation using single cell expression profiling

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Moignard, Victoria Rachel; Göttgens, Berthold

2016-01-01

Many assumptions about the way cells behave are based on analyses of populations. However, it is now widely recognized that even apparently pure populations can display a remarkable level of heterogeneity. This is particularly true in stem cell biology where it hinders our understanding of normal development and the development of strategies for regenerative medicine. Over the past decade technologies facilitating gene expression analysis at the single cell level have become widespread, provi...

Functional Expression of Programmed Death-Ligand 1 (B7-H1 by Immune Cells and Tumor Cells

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Rachel M. Gibbons Johnson

2017-08-01

Full Text Available The programmed death-1 (PD-1 and its ligand PD-L1 (B7-H1 signaling pathway has been the focus of much enthusiasm in the fields of tumor immunology and oncology with recent FDA approval of the anti-PD-1 antibodies pembrolizumab and nivolumab and the anti-PD-L1 antibodies durvalumab, atezolimuab, and avelumab. These therapies, referred to here as PD-L1/PD-1 checkpoint blockade therapies, are designed to block the interaction between PD-L1, expressed by tumor cells, and PD-1, expressed by tumor-infiltrating CD8+ T cells, leading to enhanced antitumor CD8+ T cell responses and tumor regression. The influence of PD-L1 expressed by tumor cells on antitumor CD8+ T cell responses is well characterized, but the impact of PD-L1 expressed by immune cells has not been well defined for antitumor CD8+ T cell responses. Although PD-L1 expression by tumor cells has been used as a biomarker in selection of patients for PD-L1/PD-1 checkpoint blockade therapies, patients whose tumor cells lack PD-L1 expression often respond positively to PD-L1/PD-1 checkpoint blockade therapies. This suggests that PD-L1 expressed by non-malignant cells may also contribute to antitumor immunity. Here, we review the functions of PD-L1 expressed by immune cells in the context of CD8+ T cell priming, contraction, and differentiation into memory populations, as well as the role of PD-L1 expressed by tumor cells in regulating antitumor CD8+ T cell responses.

Cell-penetrating peptide-driven Cre recombination in porcine primary cells and generation of marker-free pigs.

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Kang, Qianqian; Sun, Zhaolin; Zou, Zhiyuan; Wang, Ming; Li, Qiuyan; Hu, Xiaoxiang; Li, Ning

2018-01-01

Cell-penetrating peptides (CPPs) have been increasingly used to deliver various molecules, both in vitro and in vivo. However, there are no reports of CPPs being used in porcine fetal fibroblasts (PFFs). The increased use of transgenic pigs for basic research and biomedical applications depends on the availability of technologies for efficient genetic-modification of PFFs. Here, we report that three CPPs (CPP5, TAT, and R9) can efficiently deliver active Cre recombinase protein into PFFs via an energy-dependent endocytosis pathway. The three CPP-Cre proteins can enter PFFs and subsequently perform recombination with different efficiencies. The recombination efficacy of CPP5-Cre was found to be nearly 90%. The rate-limiting step for CPP-Cre-mediated recombination was the step of endosome escape. HA2 and chloroquine were found to improve the recombination efficiency of TAT-Cre. Furthermore, we successfully obtained marker-free transgenic pigs using TAT-Cre and CPP5-Cre. We provide a framework for the development of CPP-based farm animal transgenic technologies that would be beneficial to agriculture and biomedicine.

Expression of Cat Podoplanin in Feline Squamous Cell Carcinomas.

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Itai, Shunsuke; Yamada, Shinji; Kaneko, Mika K; Harada, Hiroyuki; Kagawa, Yumiko; Konnai, Satoru; Kato, Yukinari

2017-12-01

Oral squamous cell carcinoma is an aggressive tumor in cats; however, molecular-targeted therapies against this tumor, including antibody therapy, have not been developed. Sensitive and specific monoclonal antibodies (mAbs) against highly expressed membrane proteins are needed to develop antibody therapies. Podoplanin, a type I transmembrane glycoprotein, is expressed in many human malignant tumors, including brain tumor, esophageal cancer, lung cancer, mesothelioma, and oral cancer. Podoplanin binds to C-type lectin-like receptor-2 (CLEC-2) and activates platelet aggregation, which is involved in cancer metastasis. Until now, we have established several mAbs against podoplanin in humans, mice, rats, rabbits, dogs, cattle, and cats. We have reported podoplanin expression in canine melanoma and squamous cell carcinomas using an anti-dog podoplanin mAb PMab-38. In this study, we investigated podoplanin expression in 40 feline squamous cell carcinomas (14 cases of mouth floor, 13 of skin, 9 of ear, and 4 of tongue) by immunohistochemical analysis using an anti-cat podoplanin mAb PMab-52, which we recently developed by cell-based immunization and screening (CBIS) method. Of the total 40 cases, 38 (95%) showed positive staining for PMab-52. In particular, 12 cases (30%) showed a strong membrane-staining pattern of squamous cell carcinoma cells. PMab-52 can be useful for antibody therapy against feline podoplanin-expressing squamous cell carcinomas.

Transitional cell carcinoma express vitamin D receptors

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Hermann, G G; Andersen, C B

1997-01-01

Recently, vitamin D analogues have shown antineoplastic effect in several diseases. Vitamin D analogues exert its effect by interacting with the vitamin D receptor (VDR). Studies of VDR in transitional cell carcinoma (TCC) have not been reported. The purpose of the present study was therefore.......05). Similarly, also tumor grade appeared to be related to the number of cells expressing the receptor. Normal urothlium also expressed VDR but only with low intensity. Our study shows that TCC cells possess the VDR receptor which may make them capable to respond to stimulation with vitamin D, but functional...... studies of vitamin D's effect on TCC cells in vitro are necessary before the efficacy of treatment with vitamin D analogues in TCC can be evaluated in patients....

CNPY2 promoted the proliferation of renal cell carcinoma cells and increased the expression of TP53

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Taniguchi, Hidefumi; Ito, Saya; Ueda, Takashi; Morioka, Yukako; Kayukawa, Naruhiro; Ueno, Akihisa; Nakagawa, Hideo; Fujihara, Atsuko; Ushijima, So; Kanazawa, Motohiro; Hongo, Fumiya; Ukimura, Osamu

2017-01-01

Renal cell carcinoma (RCC) is the most common type of kidney cancer. However, the mechanisms underlying the progression of the disease are not well understood. The data in this report suggest that canopy FGF signaling regulator 2 (CNPY2) is a promoter of RCC progression. We found that CNPY2 significantly promoted growth of RCC cells and upregulated TP53 gene expression. Although TP53 is widely known as a tumor suppressor, in RCC TP53 promoted tumor cell growth. A typical p53 target gene, CDKN1A, was upregulated by both p53 and CNPY2 in RCC cells, suggesting that CNPY2 increased the expression level of TP53. Consistent with these results, CNPY2 and TP53 expression levels were positively correlated in RCC patients. These findings suggested that CNPY2 promoted cancer cell growth in RCC through regulating TP53 gene expression. - Highlights: • CNPY2 promoted growth of renal cell carcinoma (RCC) cells. • TP53 expression levels were increased by CNPY2 in RCC cells. • Growth of RCC cells was promoted by TP53. • CNPY2 expression positively correlated with TP53 expression in RCC patients.

Microarray gene expression profiling and analysis in renal cell carcinoma

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Sadhukhan Provash

2004-06-01

Full Text Available Abstract Background Renal cell carcinoma (RCC is the most common cancer in adult kidney. The accuracy of current diagnosis and prognosis of the disease and the effectiveness of the treatment for the disease are limited by the poor understanding of the disease at the molecular level. To better understand the genetics and biology of RCC, we profiled the expression of 7,129 genes in both clear cell RCC tissue and cell lines using oligonucleotide arrays. Methods Total RNAs isolated from renal cell tumors, adjacent normal tissue and metastatic RCC cell lines were hybridized to affymatrix HuFL oligonucleotide arrays. Genes were categorized into different functional groups based on the description of the Gene Ontology Consortium and analyzed based on the gene expression levels. Gene expression profiles of the tissue and cell line samples were visualized and classified by singular value decomposition. Reverse transcription polymerase chain reaction was performed to confirm the expression alterations of selected genes in RCC. Results Selected genes were annotated based on biological processes and clustered into functional groups. The expression levels of genes in each group were also analyzed. Seventy-four commonly differentially expressed genes with more than five-fold changes in RCC tissues were identified. The expression alterations of selected genes from these seventy-four genes were further verified using reverse transcription polymerase chain reaction (RT-PCR. Detailed comparison of gene expression patterns in RCC tissue and RCC cell lines shows significant differences between the two types of samples, but many important expression patterns were preserved. Conclusions This is one of the initial studies that examine the functional ontology of a large number of genes in RCC. Extensive annotation, clustering and analysis of a large number of genes based on the gene functional ontology revealed many interesting gene expression patterns in RCC. Most

Engineering of red cells of Arabidopsis thaliana and comparative genome-wide gene expression analysis of red cells versus wild-type cells.

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Shi, Ming-Zhu; Xie, De-Yu

2011-04-01

We report metabolic engineering of Arabidopsis red cells and genome-wide gene expression analysis associated with anthocyanin biosynthesis and other metabolic pathways between red cells and wild-type (WT) cells. Red cells of A. thaliana were engineered for the first time from the leaves of production of anthocyanin pigment 1-Dominant (pap1-D). These red cells produced seven anthocyanin molecules including a new one that was characterized by LC-MS analysis. Wild-type cells established as a control did not produce anthocyanins. A genome-wide microarray analysis revealed that nearly 66 and 65% of genes in the genome were expressed in the red cells and wild-type cells, respectively. In comparison with the WT cells, 3.2% of expressed genes in the red cells were differentially expressed. The expression levels of 14 genes involved in the biosynthetic pathway of anthocyanin were significantly higher in the red cells than in the WT cells. Microarray and RT-PCR analyses demonstrated that the TTG1-GL3/TT8-PAP1 complex regulated the biosynthesis of anthocyanins. Furthermore, most of the genes with significant differential expression levels in the red cells versus the WT cells were characterized with diverse biochemical functions, many of which were mapped to different metabolic pathways (e.g., ribosomal protein biosynthesis, photosynthesis, glycolysis, glyoxylate metabolism, and plant secondary metabolisms) or organelles (e.g., chloroplast). We suggest that the difference in gene expression profiles between the two cell lines likely results from cell types, the overexpression of PAP1, and the high metabolic flux toward anthocyanins.

Induced ICER Iγ down-regulates cyclin A expression and cell proliferation in insulin-producing β cells

International Nuclear Information System (INIS)

Inada, Akari; Weir, Gordon C.; Bonner-Weir, Susan

2005-01-01

We have previously found that cyclin A expression is markedly reduced in pancreatic β-cells by cell-specific overexpression of repressor inducible cyclic AMP early repressor (ICER Iγ) in transgenic mice. Here we further examined regulatory effects of ICER Iγ on cyclin A gene expression using Min6 cells, an insulin-producing cell line. The cyclin A promoter luciferase assay showed that ICER Iγ directly repressed cyclin A gene transcription. In addition, upon ICER Iγ overexpression, cyclin A mRNA levels markedly decreased, thereby confirming an inhibitory effect of ICER Iγ on cyclin A expression. Suppression of cyclin A results in inhibition of BrdU incorporation. Under normal culture conditions endogenous cyclin A is abundant in these cells, whereas ICER is hardly detectable. However, serum starvation of Min6 cells induces ICER Iγ expression with a concomitant very low expression level of cyclin A. Cyclin A protein is not expressed unless the cells are in active DNA replication. These results indicate a potentially important anti-proliferative effect of ICER Iγ in pancreatic β cells. Since ICER Iγ is greatly increased in diabetes as well as in FFA- or high glucose-treated islets, this effect may in part exacerbate diabetes by limiting β-cell proliferation

Differential expression of c-Met between primary and metastatic sites in clear-cell renal cell carcinoma and its association with PD-L1 expression.

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Lalani, Aly-Khan A; Gray, Kathryn P; Albiges, Laurence; Callea, Marcella; Pignon, Jean-Christophe; Pal, Soumitro; Gupta, Mamta; Bhatt, Rupal S; McDermott, David F; Atkins, Michael B; Woude, G F Vande; Harshman, Lauren C; Choueiri, Toni K; Signoretti, Sabina

2017-11-28

In preclinical models, c-Met promotes survival of renal cancer cells through the regulation of programmed death-ligand 1 (PD-L1). However, this relationship in human clear cell renal cell carcinoma (ccRCC) is not well characterized. We evaluated c-Met expression in ccRCC patients using paired primary and metastatic samples and assessed the association with PD-L1 expression and other clinical features. Areas with predominant and highest Fuhrman nuclear grade (FNG) were selected. c-Met expression was evaluated by IHC using an anti-Met monoclonal antibody (MET4 Ab) and calculated by a combined score (CS, 0-300): intensity of c-Met staining (0-3) x % of positive cells (0-100). PD-L1 expression in tumor cells was previously assessed by IHC and PD-L1+ was defined as PD-L1 > 0% positive cells. Our cohort consisted of 45 pairs of primary and metastatic ccRCC samples. Overall, c-Met expression was higher in metastatic sites compared to primary sites (average c-Met CS: 55 vs. 28, p = 0.0003). Higher c-Met expression was associated with higher FNG (4 vs. 3) in primary tumors (average c-Met CS: 52 vs. 20, p = 0.04). c-Met expression was numerically greater in PD-L1+ vs. PD-L1- tumors. Higher c-Met expression in metastatic sites compared to primary tumors suggests that testing for biomarkers of response to c-Met inhibitors should be conducted in metastases. While higher c-Met expression in PD-L1+ tumors requires further investigation, it supports exploring these targets in combination clinical trials.

Defining the expression of marker genes in equine mesenchymal stromal cells

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Deborah J Guest

2008-11-01

Full Text Available Deborah J Guest1, Jennifer C Ousey1, Matthew RW Smith21Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, CB8 7UU; 2Reynolds House Referrals, Greenwood Ellis and Partners, 166 High Street, Newmarket, Suffolk, CB8 9WS, UKAbstract: Mesenchymal stromal (MS cells have been derived from multiple sources in the horse including bone marrow, adipose tissue and umbilical cord blood. To date these cells have been investigated for their differentiation potential and are currently being used to treat damage to horse musculoskeletal tissues. However, no work has been done in horse MS cells to examine the expression profile of proteins and cell surface antigens that are expressed in human MS cells. The identification of such profiles in the horse will allow the comparison of putative MS cells isolated from different laboratories and different tissues. At present it is difficult to ascertain whether equivalent cells are being used in different reports. Here, we report on the expression of a range of markers used to define human MS cells. Using immunocytochemistry we show that horse MS cells homogenously express collagens, alkaline phosphatase activity, CD44, CD90 and CD29. In contrast, CD14, CD79α and the embryonic stem cell markers Oct-4, SSEA (stage specific embryonic antigen -1, -3, -4, TRA (tumor rejection antigen -1–60 and -1–81 are not expressed. The MS cells also express MHC class I antigens but do not express class II antigens, although they are inducible by treatment with interferon gamma (IFN-γ.Keywords: mesenchymal stem cells, equine, gene expression

CD40 expression in Wehi-164 cell line

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Karimi, Mohammad Hossein; Ebadi, Padideh; Pourfathollah, Ali Akbar; Soheili, Zahra Soheila; Moazzeni, Seyed Mohammad

2010-01-01

CD40-CD154 interaction is an important process for cellular and humoral immunity regulation and can be effective in the body’s defense against tumors. In the present study, we evaluated the expression of CD40 in Wehi-164 cell line. CD40 expressions on the cell surface and in the cytoplasm were assessed by flow cytometry and intracellular staining assay, respectively. Also, the mRNA expression was identified by real time-PCR. The obtained results showed the high mRNA and cytoplasmic protein ex...

Lower expression of CADM1 and higher expression of MAL in Merkel cell carcinomas are associated with Merkel cell polyomavirus infection and better prognosis.

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Iwasaki, Takeshi; Matsushita, Michiko; Nonaka, Daisuke; Nagata, Keiko; Kato, Masako; Kuwamoto, Satoshi; Murakami, Ichiro; Hayashi, Kazuhiko

2016-02-01

Merkel cell carcinoma (MCC) is a clinically aggressive neuroendocrine skin cancer; 80% of the cases are associated with the Merkel cell polyomavirus (MCPyV). We previously reported that MCPyV-negative MCCs have more irregular nuclei with abundant cytoplasm and significantly unfavorable outcomes than do MCPyV-positive MCCs. These results suggest that some cell adhesion or structural stabilization molecules are differently expressed depending on MCPyV infection status. Thus, we investigated the association of prognosis or MCPyV infection status in MCCs with cell adhesion molecule 1 (CADM1)/differentially expressed in adenocarcinoma of the lung protein 1 (DAL-1)/membrane protein, palmitoylated 3 (MPP3) tripartite complex and mal T-cell differentiation protein (MAL) expression, which play important roles in cell adhesion and oncogenesis and are related to cancer outcomes in various malignancies, to elucidate the role of these molecules. We analyzed the pathological and molecular characteristics of 26 MCPyV-positive and 15 MCPyV-negative MCCs. Univariate Cox regression analysis showed that advanced age (hazard ratio [HR], 8.249; P = .007) and high CADM1 expression (HR, 5.214; P = .012) were significantly unfavorable overall survival parameters, whereas MCPyV infection (HR, 0.043, P Merkel cells expressed DAL-1 and MAL but not CADM1. This study revealed that MCPyV-negative MCCs significantly expressed higher CADM1 and lower MAL than MCPyV-positive MCCs; these expression levels were markedly related to unfavorable outcomes. These data will give us important insights to develop novel molecular target therapies for MCCs. Copyright © 2015 Elsevier Inc. All rights reserved.

Expression pattern of matrix metalloproteinases in human gynecological cancer cell lines

International Nuclear Information System (INIS)

Schröpfer, Andrea; Kammerer, Ulrike; Kapp, Michaela; Dietl, Johannes; Feix, Sonja; Anacker, Jelena

2010-01-01

Matrix metalloproteinases (MMPs) are involved in the degradation of protein components of the extracellular matrix and thus play an important role in tumor invasion and metastasis. Their expression is related to the progression of gynecological cancers (e.g. endometrial, cervical or ovarian carcinoma). In this study we investigated the expression pattern of the 23 MMPs, currently known in humans, in different gynecological cancer cell lines. In total, cell lines from three endometrium carcinomas (Ishikawa, HEC-1-A, AN3 CA), three cervical carcinomas (HeLa, Caski, SiHa), three chorioncarcinomas (JEG, JAR, BeWo), two ovarian cancers (BG-1, OAW-42) and one teratocarcinoma (PA-1) were examined. The expression of MMPs was analyzed by RT-PCR, Western blot and gelatin zymography. We demonstrated that the cell lines examined can constitutively express a wide variety of MMPs on mRNA and protein level. While MMP-2, -11, -14 and -24 were widely expressed, no expression was seen for MMP-12, -16, -20, -25, -26, -27 in any of the cell lines. A broad range of 16 MMPs could be found in the PA1 cells and thus this cell line could be used as a positive control for general MMP experiments. While the three cervical cancer cell lines expressed 10-14 different MMPs, the median expression in endometrial and choriocarcinoma cells was 7 different enzymes. The two investigated ovarian cancer cell lines showed a distinctive difference in the number of expressed MMPs (2 vs. 10). Ishikawa, Caski, OAW-42 and BeWo cell lines could be the best choice for all future experiments on MMP regulation and their role in endometrial, cervical, ovarian or choriocarcinoma development, whereas the teratocarcinoma cell line PA1 could be used as a positive control for general MMP experiments

Differential expression of the klf6 tumor suppressor gene upon cell damaging treatments in cancer cells

International Nuclear Information System (INIS)

Gehrau, Ricardo C.; D'Astolfo, Diego S.; Andreoli, Veronica; Bocco, Jose L.; Koritschoner, Nicolas P.

2011-01-01

The mammalian Krueppel-like factor 6 (KLF6) is involved in critical roles such as growth-related signal transduction, cell proliferation and differentiation, development, apoptosis and angiogenesis. Also, KLF6 appears to be an emerging key factor during cancer development and progression. Its expression is thoroughly regulated by several cell-damaging stimuli. DNA damaging agents at lethal concentrations induce a p53-independent down-regulation of the klf6 gene. To investigate the impact of external stimuli on human klf6 gene expression, its mRNA level was analyzed using a cancer cell line profiling array system, consisting in an assortment of immobilized cDNAs from multiple cell lines treated with several cell-damaging agents at growth inhibitory concentrations (IC 50 ). Cell-damaging agents affected the klf6 expression in 62% of the cDNA samples, though the expression pattern was not dependent on the cell origin type. Interestingly, significant differences (p 50 concentrations of physical and chemical stimuli in a p53-dependent manner. Most of these agents are frequently used in cancer therapy. Induction of klf6 expression in the absence of functional p53 directly correlates with cell death triggered by these compounds, whereas it is down-regulated in p53+/+ cells. Hence, klf6 expression level could represent a valuable marker for the efficiency of cell death upon cancer treatment.

Photochemical internalisation of a macromolecular protein toxin using a cell penetrating peptide-photosensitiser conjugate.

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Wang, Julie T-W; Giuntini, Francesca; Eggleston, Ian M; Bown, Stephen G; MacRobert, Alexander J

2012-01-30

Photochemical internalisation (PCI) is a site-specific technique for improving cellular delivery of macromolecular drugs. In this study, a cell penetrating peptide, containing the core HIV-1 Tat 48-57 sequence, conjugated with a porphyrin photosensitiser has been shown to be effective for PCI. Herein we report an investigation of the photophysical and photobiological properties of a water soluble bioconjugate of the cationic Tat peptide with a hydrophobic tetraphenylporphyrin derivative. The cellular uptake and localisation of the amphiphilic bioconjugate was examined in the HN5 human head and neck squamous cell carcinoma cell line. Efficient cellular uptake and localisation in endo/lysosomal vesicles was found using fluorescence detection, and light-induced, rupture of the vesicles resulting in a more diffuse intracellular fluorescence distribution was observed. Conjugation of the Tat sequence with a hydrophobic porphyrin thus enables cellular delivery of an amphiphilic photosensitiser which can then localise in endo/lysosomal membranes, as required for effective PCI treatment. PCI efficacy was tested in combination with a protein toxin, saporin, and a significant reduction in cell viability was measured versus saporin or photosensitiser treatment alone. This study demonstrates that the cell penetrating peptide-photosensitiser bioconjugation strategy is a promising and versatile approach for enhancing the therapeutic potential of bioactive agents through photochemical internalisation. Copyright © 2011 Elsevier B.V. All rights reserved.

Tat proteins as novel thylakoid membrane anchors organize a biosynthetic pathway in chloroplasts and increase product yield 5-fold

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Henriques de Jesus, Maria Perestrello Ramos; Nielsen, Agnieszka Janina Zygadlo; Mellor, Silas Busck

2017-01-01

to their complex structures. Some of the crucial enzymes catalyzing their biosynthesis are the cytochromes P450 (P450s) situated in the endoplasmic reticulum (ER), powered by electron transfers from NADPH. Dhurrin is a cyanogenic glucoside and its biosynthesis involves a dynamic metabolon formed by two P450s....... Nevertheless, translocation of the pathway from the ER to the chloroplast creates other difficulties, such as the loss of metabolon formation and intermediate diversion into other metabolic pathways. We show here that co-localization of these enzymes in the thylakoid membrane leads to a significant increase...... in product formation, with a concomitant decrease in off-pathway intermediates. This was achieved by exchanging the membrane anchors of the dhurrin pathway enzymes to components of the Twin-arginine translocation pathway, TatB and TatC, which have self-assembly properties. Consequently, we show 5-fold...

High epitope expression levels increase competition between T cells.

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Almut Scherer

2006-08-01

Full Text Available Both theoretical predictions and experimental findings suggest that T cell populations can compete with each other. There is some debate on whether T cells compete for aspecific stimuli, such as access to the surface on antigen-presenting cells (APCs or for specific stimuli, such as their cognate epitope ligand. We have developed an individual-based computer simulation model to study T cell competition. Our model shows that the expression level of foreign epitopes per APC determines whether T cell competition is mainly for specific or aspecific stimuli. Under low epitope expression, competition is mainly for the specific epitope stimuli, and, hence, different epitope-specific T cell populations coexist readily. However, if epitope expression levels are high, aspecific competition becomes more important. Such between-specificity competition can lead to competitive exclusion between different epitope-specific T cell populations. Our model allows us to delineate the circumstances that facilitate coexistence of T cells of different epitope specificity. Understanding mechanisms of T cell coexistence has important practical implications for immune therapies that require a broad immune response.

HLA-E-expressing pluripotent stem cells escape allogeneic responses and lysis by NK cells.

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Gornalusse, Germán G; Hirata, Roli K; Funk, Sarah E; Riolobos, Laura; Lopes, Vanda S; Manske, Gabriel; Prunkard, Donna; Colunga, Aric G; Hanafi, Laïla-Aïcha; Clegg, Dennis O; Turtle, Cameron; Russell, David W

2017-08-01

Polymorphisms in the human leukocyte antigen (HLA) class I genes can cause the rejection of pluripotent stem cell (PSC)-derived products in allogeneic recipients. Disruption of the Beta-2 Microglobulin (B2M) gene eliminates surface expression of all class I molecules, but leaves the cells vulnerable to lysis by natural killer (NK) cells. Here we show that this 'missing-self' response can be prevented by forced expression of minimally polymorphic HLA-E molecules. We use adeno-associated virus (AAV)-mediated gene editing to knock in HLA-E genes at the B2M locus in human PSCs in a manner that confers inducible, regulated, surface expression of HLA-E single-chain dimers (fused to B2M) or trimers (fused to B2M and a peptide antigen), without surface expression of HLA-A, B or C. These HLA-engineered PSCs and their differentiated derivatives are not recognized as allogeneic by CD8 + T cells, do not bind anti-HLA antibodies and are resistant to NK-mediated lysis. Our approach provides a potential source of universal donor cells for applications where the differentiated derivatives lack HLA class II expression.

HLA-E-expressing pluripotent stem cells escape allogeneic responses and lysis by NK cells

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Gornalusse, Germán G.; Hirata, Roli K.; Funk, Sarah; Riolobos, Laura; Lopes, Vanda S.; Manske, Gabriel; Prunkard, Donna; Colunga, Aric G.; Hanafi, Laïla-Aïcha; Clegg, Dennis O.; Turtle, Cameron; Russell, David W.

2017-01-01

Polymorphisms in the human leukocyte antigen (HLA) class I genes can cause the rejection of pluripotent stem cell (PSC)-derived products in allogeneic recipients. Disruption of the Beta-2 Microglobulin (B2M) gene eliminates surface expression of all class I molecules, but leaves the cells vulnerable to lysis by natural killer (NK) cells. Here we show that this ‘missing self’ response can be prevented by forced expression of minimally polymorphic HLA-E molecules. We use adeno-associated virus (AAV)-mediated gene editing to knock in HLA-E genes at the B2M locus in human PSCs in a manner that confers inducible, regulated, surface expression of HLA-E single-chain dimers (fused to B2M) or trimers (fused to B2M and a peptide antigen), without surface expression of HLA-A, B or C. These HLA-engineered PSCs and their differentiated derivatives are not recognized as allogeneic by CD8+ T cells, do not bind anti-HLA antibodies, and are resistant to NK-mediated lysis. Our approach provides a potential source of universal donor cells for applications where the differentiated derivatives lack HLA class II expression. PMID:28504668

Expression of Pluripotency Markers in Nonpluripotent Human Neural Stem and Progenitor Cells.

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Vincent, Per Henrik; Benedikz, Eirikur; Uhlén, Per; Hovatta, Outi; Sundström, Erik

2017-06-15

Nonpluripotent neural progenitor cells (NPCs) derived from the human fetal central nervous system were found to express a number of messenger RNA (mRNA) species associated with pluripotency, such as NANOG, REX1, and OCT4. The expression was restricted to small subpopulations of NPCs. In contrast to pluripotent stem cells, there was no coexpression of the pluripotency-associated genes studied. Although the expression of these genes rapidly declined during the in vitro differentiation of NPCs, we found no evidence that the discrete expression was associated with the markers of multipotent neural stem cells (CD133 + /CD24 lo ), the capacity of sphere formation, or high cell proliferation rates. The rate of cell death among NPCs expressing pluripotency-associated genes was also similar to that of other NPCs. Live cell imaging showed that NANOG- and REX1-expressing NPCs continuously changed morphology, as did the nonexpressing cells. Depletion experiments showed that after the complete removal of the subpopulations of NANOG- and REX1-expressing NPCs, the expression of these genes appeared in other NPCs within a few days. The percentage of NANOG- and REX1-expressing cells returned to that observed before depletion. Our results are best explained by a model in which there is stochastic transient expression of pluripotency-associated genes in proliferating NPCs.

Spatial reconstruction of single-cell gene expression data.

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Satija, Rahul; Farrell, Jeffrey A; Gennert, David; Schier, Alexander F; Regev, Aviv

2015-05-01

Spatial localization is a key determinant of cellular fate and behavior, but methods for spatially resolved, transcriptome-wide gene expression profiling across complex tissues are lacking. RNA staining methods assay only a small number of transcripts, whereas single-cell RNA-seq, which measures global gene expression, separates cells from their native spatial context. Here we present Seurat, a computational strategy to infer cellular localization by integrating single-cell RNA-seq data with in situ RNA patterns. We applied Seurat to spatially map 851 single cells from dissociated zebrafish (Danio rerio) embryos and generated a transcriptome-wide map of spatial patterning. We confirmed Seurat's accuracy using several experimental approaches, then used the strategy to identify a set of archetypal expression patterns and spatial markers. Seurat correctly localizes rare subpopulations, accurately mapping both spatially restricted and scattered groups. Seurat will be applicable to mapping cellular localization within complex patterned tissues in diverse systems.

Angiotensin II reduces cardiac AdipoR1 expression through AT1 receptor/ROS/ERK1/2/c-Myc pathway.

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Li Li

Full Text Available Adiponectin, an abundant adipose tissue-derived protein, exerts protective effect against cardiovascular disease. Adiponectin receptors (AdipoR1 and AdipoR2 mediate the beneficial effects of adiponectin on the cardiovascular system. However, the alteration of AdipoRs in cardiac remodeling is not fully elucidated. Here, we investigated the effect of angiotensin II (AngII on cardiac AdipoRs expression and explored the possible molecular mechanism. AngII infusion into rats induced cardiac hypertrophy, reduced AdipoR1 but not AdipoR2 expression, and attenuated the phosphorylations of adenosine monophosphate-activated protein kinase and acetyl coenzyme A carboxylase, and those effects were all reversed by losartan, an AngII type 1 (AT1 receptor blocker. AngII reduced expression of AdipoR1 mRNA and protein in cultured neonatal rat cardiomyocytes, which was abolished by losartan, but not by PD123319, an AT2 receptor antagonist. The antioxidants including reactive oxygen species (ROS scavenger NAC, NADPH oxidase inhibitor apocynin, Nox2 inhibitor peptide gp91 ds-tat, and mitochondrial electron transport chain complex I inhibitor rotenone attenuated AngII-induced production of ROS and phosphorylation of extracellular signal-regulated kinase (ERK 1/2. AngII-reduced AdipoR1 expression was reversed by pretreatment with NAC, apocynin, gp91 ds-tat, rotenone, and an ERK1/2 inhibitor PD98059. Chromatin immunoprecipitation assay demonstrated that AngII provoked the recruitment of c-Myc onto the promoter region of AdipoR1, which was attenuated by PD98059. Moreover, AngII-induced DNA binding activity of c-Myc was inhibited by losartan, NAC, apocynin, gp91 ds-tat, rotenone, and PD98059. c-Myc small interfering RNA abolished the inhibitory effect of AngII on AdipoR1 expression. Our results suggest that AngII inhibits cardiac AdipoR1 expression in vivo and in vitro and AT1 receptor/ROS/ERK1/2/c-Myc pathway is required for the downregulation of AdipoR1 induced by AngII.

Protein Expression Analyses at the Single Cell Level

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Masae Ohno

2014-09-01

Full Text Available The central dogma of molecular biology explains how genetic information is converted into its end product, proteins, which are responsible for the phenotypic state of the cell. Along with the protein type, the phenotypic state depends on the protein copy number. Therefore, quantification of the protein expression in a single cell is critical for quantitative characterization of the phenotypic states. Protein expression is typically a dynamic and stochastic phenomenon that cannot be well described by standard experimental methods. As an alternative, fluorescence imaging is being explored for the study of protein expression, because of its high sensitivity and high throughput. Here we review key recent progresses in fluorescence imaging-based methods and discuss their application to proteome analysis at the single cell level.

Matrix metalloproteinase-9 expression in folliculostellate cells of rat anterior pituitary gland.

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Ilmiawati, Cimi; Horiguchi, Kotaro; Fujiwara, Ken; Yashiro, Takashi

2012-03-01

Folliculostellate (FS) cells of the anterior pituitary gland express a variety of regulatory molecules. Using transgenic rats that express green fluorescent protein specifically in FS cells, we recently demonstrated that FS cells in vitro showed marked changes in motility, proliferation, and that formation of cellular interconnections in the presence of laminin, a component of the extracellular matrix, closely resembled those observed in vivo. These findings suggested that FS cells express matrix metalloproteinase-9 (MMP-9), which assists their function on laminin. In the present study, we investigate MMP-9 expression in rat anterior pituitary gland and examine its role in motility and proliferation of FS cells on laminin. Immunohistochemistry, RT-PCR, immunoblotting, and gelatin zymography were performed to assess MMP-9 expression in the anterior pituitary gland and cultured FS cells. Real-time RT-PCR was used to quantify MMP-9 expression in cultured FS cells under different conditions and treatments. MMP-9 expression was inhibited by pharmacological inhibitor or downregulated by siRNA and time-lapse images were acquired. A 5-bromo-2'-deoxyuridine assay was performed to analyze the proliferation of FS cells. Our results showed that MMP-9 was expressed in FS cells, that this expression was upregulated by laminin, and that laminin induced MMP-9 secretion by FS cells. MMP-9 inhibition and downregulation did not impair FS motility; however, it did impair the capacity of FS cells to form interconnections and it significantly inhibited proliferation of FS cells on laminin. We conclude that MMP-9 is necessary in FS cell interconnection and proliferation in the presence of laminin.