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Sample records for autophagy mediates pharmacological

  1. Cocaine induces astrocytosis through ER stress-mediated activation of autophagy.

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    Periyasamy, Palsamy; Guo, Ming-Lei; Buch, Shilpa

    2016-08-01

    Cocaine is known to induce inflammation, thereby contributing in part, to the pathogenesis of neurodegeneration. A recent study from our lab has revealed a link between macroautophagy/autophagy and microglial activation. The current study was aimed at investigating whether cocaine could also mediate activation of astrocytes and, whether this process involved induction of autophagy. Our findings demonstrated that cocaine mediated the activation of astrocytes by altering the levels of autophagy markers, such as BECN1, ATG5, MAP1LC3B-II, and SQSTM1 in both human A172 astrocytoma cells and primary human astrocytes. Furthermore, cocaine treatment resulted in increased formation of endogenous MAP1LC3B puncta in human astrocytes. Additionally, astrocytes transfected with the GFP-MAP1LC3B plasmid also demonstrated cocaine-mediated upregulation of the green fluorescent MAP1LC3B puncta. Cocaine-mediated induction of autophagy involved upstream activation of ER stress proteins such as EIF2AK3, ERN1, ATF6 since blockage of autophagy using either pharmacological or gene-silencing approaches, had no effect on cocaine-mediated induction of ER stress. Using both pharmacological and gene-silencing approaches to block either ER stress or autophagy, our findings demonstrated that cocaine-induced activation of astrocytes (measured by increased levels of GFAP) involved sequential activation of ER stress and autophagy. Cocaine-mediated-increased upregulation of GFAP correlated with increased expression of proinflammatory mediators such as TNF, IL1B, and IL6. In conclusion, these findings reveal an association between ER stress-mediated autophagy and astrogliosis in cocaine-treated astrocytes. Intervention of ER stress and/or autophagy signaling would thus be promising therapeutic targets for abrogating cocaine-mediated neuroinflammation. PMID:27337297

  2. Degradation of AF1Q by chaperone-mediated autophagy

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    Li, Peng; Ji, Min; Lu, Fei; Zhang, Jingru [Department of Hematology, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital, Shandong University, Jinan 250012 (China); Li, Huanjie; Cui, Taixing; Li Wang, Xing [Research Center for Cell Therapy, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital, Shandong University, Jinan 250012 (China); Tang, Dongqi, E-mail: tangdq@sdu.edu.cn [Research Center for Cell Therapy, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital, Shandong University, Jinan 250012 (China); Center for Stem Cell and Regenerative Medicine, The Second Hospital of Shandong University, Jinan 250033 (China); Ji, Chunyan, E-mail: jichunyan@sdu.edu.cn [Department of Hematology, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital, Shandong University, Jinan 250012 (China)

    2014-09-10

    AF1Q, a mixed lineage leukemia gene fusion partner, is identified as a poor prognostic biomarker for pediatric acute myeloid leukemia (AML), adult AML with normal cytogenetic and adult myelodysplastic syndrome. AF1Q is highly regulated during hematopoietic progenitor differentiation and development but its regulatory mechanism has not been defined clearly. In the present study, we used pharmacological and genetic approaches to influence chaperone-mediated autophagy (CMA) and explored the degradation mechanism of AF1Q. Pharmacological inhibitors of lysosomal degradation, such as chloroquine, increased AF1Q levels, whereas activators of CMA, including 6-aminonicotinamide and nutrient starvation, decreased AF1Q levels. AF1Q interacts with HSPA8 and LAMP-2A, which are core components of the CMA machinery. Knockdown of HSPA8 or LAMP-2A increased AF1Q protein levels, whereas overexpression showed the opposite effect. Using an amino acid deletion AF1Q mutation plasmid, we identified that AF1Q had a KFERQ-like motif which was recognized by HSPA8 for CMA-dependent proteolysis. In conclusion, we demonstrate for the first time that AF1Q can be degraded in lysosomes by CMA. - Highlights: • Chaperone-mediated autophagy (CMA) is involved in the degradation of AF1Q. • Macroautophagy does not contribute to the AF1Q degradation. • AF1Q has a KFERQ-like motif that is recognized by CMA core components.

  3. Caloric restriction mimetics: natural/physiological pharmacological autophagy inducers.

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    Mariño, Guillermo; Pietrocola, Federico; Madeo, Frank; Kroemer, Guido

    2014-01-01

    Nutrient depletion, which is one of the physiological triggers of autophagy, results in the depletion of intracellular acetyl coenzyme A (AcCoA) coupled to the deacetylation of cellular proteins. We surmise that there are 3 possibilities to mimic these effects, namely (i) the depletion of cytosolic AcCoA by interfering with its biosynthesis, (ii) the inhibition of acetyltransferases, which are enzymes that transfer acetyl groups from AcCoA to other molecules, mostly leucine residues in cellular proteins, or (iii) the stimulation of deacetylases, which catalyze the removal of acetyl groups from leucine residues. There are several examples of rather nontoxic natural compounds that act as AcCoA depleting agents (e.g., hydroxycitrate), acetyltransferase inhibitors (e.g., anacardic acid, curcumin, epigallocatechin-3-gallate, garcinol, spermidine) or deacetylase activators (e.g., nicotinamide, resveratrol), and that are highly efficient inducers of autophagy in vitro and in vivo, in rodents. Another common characteristic of these agents is their capacity to reduce aging-associated diseases and to confer protective responses against ischemia-induced organ damage. Hence, we classify them as "caloric restriction mimetics" (CRM). Here, we speculate that CRM may mediate their broad health-improving effects by triggering the same molecular pathways that usually are elicited by long-term caloric restriction or short-term starvation and that imply the induction of autophagy as an obligatory event conferring organismal, organ- or cytoprotection. PMID:25484097

  4. Autophagy is required for IL-2-mediated fibroblast growth

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    Autophagy is an evolutionarily conserved pathway responsible for delivery of cytoplasmic material into the lysosomal degradation pathway to enable vesicular exocytosis. Interleukin (IL)-2 is produced by T-cells and its activity is important for immunoregulation. Fibroblasts are an immune competent cell type, playing a critical role in wound healing, chronic inflammation, and tumor development. Although autophagy plays an important role in each of these processes, whether it regulates IL-2 activity in fibroblasts is unknown. Here, we show that autophagy is required for IL-2-induced cell growth in fibroblasts. IL-2 significantly induced autophagy in mouse embryonic fibroblasts (MEFs) and primary lung fibroblasts. Autophagy inhibitors (e.g., 3-methylamphetamine and bafilomycin A1) or knockdown of ATG5 and beclin 1 blocked clinical grade IL-2-induced autophagy. Moreover, IL-2 induced HMGB1 cytoplasmic translocation in MEFs and promoted interaction between HMGB1 and beclin1, which is required for autophagy induction. Pharmacological and genetic inhibition of autophagy inhibited IL-2-induced cell proliferation and enhanced IL-2-induced apoptosis. These findings suggest that autophagy is an important pro-survival regulator for IL-2-induced cell growth in fibroblasts

  5. Autophagy is required for IL-2-mediated fibroblast growth

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    Kang, Rui [Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania 15219 (United States); Tang, Daolin, E-mail: tangd2@upmc.edu [Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania 15219 (United States); Lotze, Michael T., E-mail: lotzemt@upcm.edu [Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania 15219 (United States); Zeh III, Herbert J., E-mail: zehh@upmc.edu [Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania 15219 (United States)

    2013-02-15

    Autophagy is an evolutionarily conserved pathway responsible for delivery of cytoplasmic material into the lysosomal degradation pathway to enable vesicular exocytosis. Interleukin (IL)-2 is produced by T-cells and its activity is important for immunoregulation. Fibroblasts are an immune competent cell type, playing a critical role in wound healing, chronic inflammation, and tumor development. Although autophagy plays an important role in each of these processes, whether it regulates IL-2 activity in fibroblasts is unknown. Here, we show that autophagy is required for IL-2-induced cell growth in fibroblasts. IL-2 significantly induced autophagy in mouse embryonic fibroblasts (MEFs) and primary lung fibroblasts. Autophagy inhibitors (e.g., 3-methylamphetamine and bafilomycin A1) or knockdown of ATG5 and beclin 1 blocked clinical grade IL-2-induced autophagy. Moreover, IL-2 induced HMGB1 cytoplasmic translocation in MEFs and promoted interaction between HMGB1 and beclin1, which is required for autophagy induction. Pharmacological and genetic inhibition of autophagy inhibited IL-2-induced cell proliferation and enhanced IL-2-induced apoptosis. These findings suggest that autophagy is an important pro-survival regulator for IL-2-induced cell growth in fibroblasts.

  6. New Potential Pharmacological Functions of Chinese Herbal Medicines via Regulation of Autophagy

    Directory of Open Access Journals (Sweden)

    Betty Yuen Kwan Law

    2016-03-01

    Full Text Available Autophagy is a universal catabolic cellular process for quality control of cytoplasm and maintenance of cellular homeostasis upon nutrient deprivation and environmental stimulus. It involves the lysosomal degradation of cellular components such as misfolded proteins or damaged organelles. Defects in autophagy are implicated in the pathogenesis of diseases including cancers, myopathy, neurodegenerations, infections and cardiovascular diseases. In the recent decade, traditional drugs with new clinical applications are not only commonly found in Western medicines, but also highlighted in Chinese herbal medicines (CHM. For instance, pharmacological studies have revealed that active components or fractions from Chaihu (Radix bupleuri, Hu Zhang (Rhizoma polygoni cuspidati, Donglingcao (Rabdosia rubesens, Hou po (Cortex magnoliae officinalis and Chuan xiong (Rhizoma chuanxiong modulate cancers, neurodegeneration and cardiovascular disease via autophagy. These findings shed light on the potential new applications and formulation of CHM decoctions via regulation of autophagy. This article reviews the roles of autophagy in the pharmacological actions of CHM and discusses their new potential clinical applications in various human diseases.

  7. Caloric restriction mimetics: natural/physiological pharmacological autophagy inducers

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    Mariño, Guillermo; Pietrocola, Federico; Madeo, Frank; Kroemer, Guido

    2014-01-01

    Nutrient depletion, which is one of the physiological triggers of autophagy, results in the depletion of intracellular acetyl coenzyme A (AcCoA) coupled to the deacetylation of cellular proteins. We surmise that there are 3 possibilities to mimic these effects, namely (i) the depletion of cytosolic AcCoA by interfering with its biosynthesis, (ii) the inhibition of acetyltransferases, which are enzymes that transfer acetyl groups from AcCoA to other molecules, mostly leucine residues in cellul...

  8. Pharmacologic preconditioning with berberine attenuating ischemia-induced apoptosis and promoting autophagy in neuron.

    Science.gov (United States)

    Zhang, Qichun; Bian, Huimin; Guo, Liwei; Zhu, Huaxu

    2016-01-01

    Pharmacologic preconditioning is an intriguing and emerging approach adopted to prevent injury of ischemia/reperfusion. Neuroprotection is the cardinal effect of these pleiotropic actions of berberine. Here we investigated that whether berberine could acts as a preconditioning stimuli contributing to attenuate hypoxia-induced neurons death as well. Male Sprague-Dawley rats of middle cerebral artery occlusion (MCAO) and rat primary cortical neurons undergoing oxygen and glucose deprivation (OGD) were preconditioned with berberine (40 mg/kg, for 24 h in vivo, and 10(-6) mol/L, for 2 h in vitro, respectively). The neurological deficits and cerebral water contents of MCAO rats were evaluated. The autophagy and apoptosis were further determined in primary neurons in vitro. Berberine preconditioning (BP) was then shown to ameliorate the neurological deficits, decrease cerebral water content and promote neurogenesis of MCAO rats. Decreased LDH release from OGD-treated neurons was observed via BP, which was blocked by LY294002 (20 µmol/L), GSK690693 (10 µmol/L), or YC-1 (25 µmol/L). Furthermore, BP stimulated autophagy and inhibited apoptosis via modulated the autophagy-associated proteins LC 3, Beclin-1 and p62, and apoptosis-modulating proteins caspase 3, caspase 8, caspase 9, PARP and BCL-2/Bax. In conclusion, berberine acts as a stimulus of preconditioning that exhibits neuroprotection via promoting autophagy and decreasing anoxia-induced apoptosis. PMID:27158406

  9. STAT3-Mediated Autophagy Dependence Identifies Subtypes of Breast Cancer where Autophagy Inhibition can be Efficacious

    OpenAIRE

    Maycotte, Paola; Gearheart, Christy M.; Barnard, Rebecca; Aryal, Suraj; Mulcahy Levy, Jean M.; Fosmire, Susan P.; Hansen, Ryan J.; Morgan, Michael J.; Christopher C Porter; Gustafson, Daniel L.; Thorburn, Andrew

    2014-01-01

    Autophagy is a protein and organelle degradation pathway that is involved in diverse diseases including cancer. Recent evidence suggests that autophagy is a cell survival mechanism in tumor cells and that its inhibition especially in combination with other therapy could be beneficial but it remains unclear if all cancer cells behave the same way when autophagy is inhibited. We inhibited autophagy in a panel of breast cancer cell lines and found that some of them are dependent on autophagy for...

  10. Pharmacological strategies in lung cancer-induced cachexia: effects on muscle proteolysis, autophagy, structure, and weakness.

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    Chacon-Cabrera, Alba; Fermoselle, Clara; Urtreger, Alejandro J; Mateu-Jimenez, Mercè; Diament, Miriam J; de Kier Joffé, Elisa D Bal; Sandri, Marco; Barreiro, Esther

    2014-11-01

    Cachexia is a relevant comorbid condition of chronic diseases including cancer. Inflammation, oxidative stress, autophagy, ubiquitin-proteasome system, nuclear factor (NF)-κB, and mitogen-activated protein kinases (MAPK) are involved in the pathophysiology of cancer cachexia. Currently available treatment is limited and data demonstrating effectiveness in in vivo models are lacking. Our objectives were to explore in respiratory and limb muscles of lung cancer (LC) cachectic mice whether proteasome, NF-κB, and MAPK inhibitors improve muscle mass and function loss through several molecular mechanisms. Body and muscle weights, limb muscle force, protein degradation and the ubiquitin-proteasome system, signaling pathways, oxidative stress and inflammation, autophagy, contractile and functional proteins, myostatin and myogenin, and muscle structure were evaluated in the diaphragm and gastrocnemius of LC (LP07 adenocarcinoma) bearing cachectic mice (BALB/c), with and without concomitant treatment with NF-κB (sulfasalazine), MAPK (U0126), and proteasome (bortezomib) inhibitors. Compared to control animals, in both respiratory and limb muscles of LC cachectic mice: muscle proteolysis, ubiquitinated proteins, autophagy, myostatin, protein oxidation, FoxO-1, NF-κB and MAPK signaling pathways, and muscle abnormalities were increased, while myosin, creatine kinase, myogenin, and slow- and fast-twitch muscle fiber size were decreased. Pharmacological inhibition of NF-κB and MAPK, but not the proteasome system, induced in cancer cachectic animals, a substantial restoration of muscle mass and force through a decrease in muscle protein oxidation and catabolism, myostatin, and autophagy, together with a greater content of myogenin, and contractile and functional proteins. Attenuation of MAPK and NF-κB signaling pathway effects on muscles is beneficial in cancer-induced cachexia. PMID:24615622

  11. Ras-Related Tumorigenesis Is Suppressed by BNIP3-Mediated Autophagy through Inhibition of Cell Proliferation

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    Shan-Ying Wu

    2011-12-01

    Full Text Available Autophagy plays diverse roles in Ras-related tumorigenesis. H-rasval12 induces autophagy through multiple signaling pathways including Raf-1/ERK pathway, and various ERK downstream molecules of autophagy have been reported. In this study, Bcl-2/adenovirus E1B 19-kDa–interacting protein 3 (BNIP3 is identified as a downstream transducer of the Ras/Raf/ERK signaling pathway to induce autophagy. BNIP3 was upregulated by H-rasval12 at the transcriptional level to compete with Beclin 1 for binding with Bcl-2. H-rasval12–induced autophagy suppresses cell proliferation demonstrated both in vitro and in vivo by expression of ectopic BNIP3, Atg5, or interference RNA of BNIP3 (siBNIP3 and Atg5 (shAtg5 using mouse NIH3T3 and embryo fibroblast cells. H-rasval12 induces different autophagic responses depending on the duration of Ras overexpression. After a short time (48 hours of Ras overexpression, autophagy inhibits cell proliferation. In contrast, a longer time (2 weeks of Ras overexpression, cell proliferation was enhanced by autophagy. Furthermore, overexpression of mutant Ras, BNIP3, and LC3-II was detected in bladder cancer T24 cells and the tumor parts of 75% of bladder cancer specimens indicating a positive correlation between autophagy and tumorigenesis. Taken together, our mouse model demonstrates a balance between BNIP3-mediated autophagy and H-rasval12–induced tumor formation and reveals that H-rasval12 induces autophagy in a BNIP3-dependent manner, and the threshold of autophagy plays a decisive role in H-rasval12–induced tumorigenesis. Our findings combined with others’ reports suggest a new therapeutic strategy against Ras-related tumorigenesis by negative or positive regulation of autophagic activity, which is determined by the level of autophagy and tumor progression stages.

  12. Modulation of deregulated chaperone-mediated autophagy by a phosphopeptide.

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    Macri, Christophe; Wang, Fengjuan; Tasset, Inmaculada; Schall, Nicolas; Page, Nicolas; Briand, Jean-Paul; Cuervo, Ana Maria; Muller, Sylviane

    2015-01-01

    The P140 peptide, a 21-mer linear peptide (sequence 131-151) generated from the spliceosomal SNRNP70/U1-70K protein, contains a phosphoserine residue at position 140. It significantly ameliorates clinical manifestations in autoimmune patients with systemic lupus erythematosus and enhances survival in MRL/lpr lupus-prone mice. Previous studies showed that after P140 treatment, there is an accumulation of autophagy markers sequestosome 1/p62 and MAP1LC3-II in MRL/lpr B cells, consistent with a downregulation of autophagic flux. We now identify chaperone-mediated autophagy (CMA) as a target of P140 and demonstrate that its inhibitory effect on CMA is likely tied to its ability to alter the composition of HSPA8/HSC70 heterocomplexes. As in the case of HSPA8, expression of the limiting CMA component LAMP2A, which is increased in MRL/lpr B cells, is downregulated after P140 treatment. We also show that P140, but not the unphosphorylated peptide, uses the clathrin-dependent endo-lysosomal pathway to enter into MRL/lpr B lymphocytes and accumulates in the lysosomal lumen where it may directly hamper lysosomal HSPA8 chaperoning functions, and also destabilize LAMP2A in lysosomes as a result of its effect on HSP90AA1. This dual effect may interfere with the endogenous autoantigen processing and loading to major histocompatibility complex class II molecules and as a consequence, lead to lower activation of autoreactive T cells. These results shed light on mechanisms by which P140 can modulate lupus disease and exert its tolerogenic activity in patients. The unique selective inhibitory effect of the P140 peptide on CMA may be harnessed in other pathological conditions in which reduction of CMA activity would be desired. PMID:25719862

  13. Cardiomyocyte ryanodine receptor degradation by chaperone-mediated autophagy

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    Pedrozo, Zully; Torrealba, Natalia; Fernández, Carolina; Gatica, Damian; Toro, Barbra; Quiroga, Clara; Rodriguez, Andrea E.; Sanchez, Gina; Gillette, Thomas G.; Hill, Joseph A.; Donoso, Paulina; Lavandero, Sergio

    2013-01-01

    Time for primary review: 15 days Aims Chaperone-mediated autophagy (CMA) is a selective mechanism for the degradation of soluble cytosolic proteins bearing the sequence KFERQ. These proteins are targeted by chaperones and delivered to lysosomes where they are translocated into the lysosomal lumen and degraded via the lysosome-associated membrane protein type 2A (LAMP-2A). Mutations in LAMP2 that inhibit autophagy result in Danon disease characterized by hypertrophic cardiomyopathy. The ryanodine receptor type 2 (RyR2) plays a key role in cardiomyocyte excitation–contraction and its dysfunction can lead to cardiac failure. Whether RyR2 is degraded by CMA is unknown. Methods and results To induce CMA, cultured neonatal rat cardiomyocytes were treated with geldanamycin (GA) to promote protein degradation through this pathway. GA increased LAMP-2A levels together with its redistribution and colocalization with Hsc70 in the perinuclear region, changes indicative of CMA activation. The inhibition of lysosomes but not proteasomes prevented the loss of RyR2. The recovery of RyR2 content after incubation with GA by siRNA targeting LAMP-2A suggests that RyR2 is degraded via CMA. In silico analysis also revealed that the RyR2 sequence harbours six KFERQ motifs which are required for the recognition Hsc70 and its degradation via CMA. Our data suggest that presenilins are involved in RyR2 degradation by CMA. Conclusion These findings are consistent with a model in which oxidative damage of the RyR2 targets it for turnover by presenilins and CMA, which could lead to removal of damaged or leaky RyR2 channels. PMID:23404999

  14. Dexamethasone-induced autophagy mediates muscle atrophy through mitochondrial clearance

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    Troncoso, Rodrigo; Paredes, Felipe; Parra, Valentina; Gatica, Damián; Vásquez-Trincado, César; Quiroga, Clara; Bravo-Sagua, Roberto; López-Crisosto, Camila; Rodriguez, Andrea E; Oyarzún, Alejandra P; Kroemer, Guido; Lavandero, Sergio

    2014-01-01

    Glucocorticoids, such as dexamethasone, enhance protein breakdown via ubiquitin–proteasome system. However, the role of autophagy in organelle and protein turnover in the glucocorticoid-dependent atrophy program remains unknown. Here, we show that dexamethasone stimulates an early activation of autophagy in L6 myotubes depending on protein kinase, AMPK, and glucocorticoid receptor activity. Dexamethasone increases expression of several autophagy genes, including ATG5, LC3, BECN1, and SQSTM1 a...

  15. Impact of Air Pollutants on Oxidative Stress in Common Autophagy-Mediated Aging Diseases

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    Mohamed Saber Numan

    2015-02-01

    Full Text Available Atmospheric pollution-induced cellular oxidative stress is probably one of the pathogenic mechanisms involved in most of the common autophagy-mediated aging diseases, including neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS, Alzheimer’s, disease, as well as Paget’s disease of bone with or without frontotemporal dementia and inclusion body myopathy. Oxidative stress has serious damaging effects on the cellular contents: DNA, RNA, cellular proteins, and cellular organelles. Autophagy has a pivotal role in recycling these damaged non-functional organelles and misfolded or unfolded proteins. In this paper, we highlight, through a narrative review of the literature, that when autophagy processes are impaired during aging, in presence of cumulative air pollution-induced cellular oxidative stress and due to a direct effect on air pollutant, autophagy-mediated aging diseases may occur.

  16. Protective Effects of Gastrodin Against Autophagy-Mediated Astrocyte Death.

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    Wang, Xin-Shang; Tian, Zhen; Zhang, Nan; Han, Jing; Guo, Hong-Liang; Zhao, Ming-Gao; Liu, Shui-Bing

    2016-03-01

    Gastrodin is an active ingredient derived from the rhizome of Gastrodia elata. This compound is usually used to treat convulsive illness, dizziness, vertigo, and headache. This study aimed to investigate the effect of gastrodin on the autophagy of glial cells exposed to lipopolysaccharides (LPS, 1 µg/mL). Autophagy is a form of programmed cell death, although it also promotes cell survival. In cultured astrocytes, LPS exposure induced excessive autophagy and apoptosis, which were significantly prevented by the pretreatment cells with gastrodin (10 μM). The protective effects of gastrodin via autophagy inhibition were verified by the decreased levels of LC3-II, P62, and Beclin-1, which are classical markers for autophagy. Furthermore, gastrodin protected astrocytes from apoptosis through Bcl-2 and Bax signaling pathway. The treatment of astrocytes with rapamycin (500 nM), wortmannin (100 nM), and LY294002 (10 μM), which are inhibitors of mTOR and PI3K, respectively, eliminated the known effects of gastrodin on the inhibited Beclin-1 expression. Furthermore, gastrodin blocked the down-regulation of glutamine synthetase induced by LPS exposure in astrocytes. Our results suggest that gastrodin can be used as a preventive agent for the excessive autophagy induced by LPS. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26643508

  17. Calpain 2-mediated autophagy defect increases susceptibility of fatty livers to ischemia-reperfusion injury.

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    Zhao, Q; Guo, Z; Deng, W; Fu, S; Zhang, C; Chen, M; Ju, W; Wang, D; He, X

    2016-01-01

    Hepatic steatosis is associated with significant morbidity and mortality after liver resection and transplantation. This study focuses on the role of autophagy in regulating sensitivity of fatty livers to ischemia and reperfusion (I/R) injury. Quantitative immunohistochemistry conducted on human liver allograft biopsies showed that, the reduction of autophagy markers LC3 and Beclin-1 at 1 h after reperfusion, was correlated with hepatic steatosis and poor survival of liver transplant recipients. In animal studies, western blotting and confocal imaging analysis associated the increase in sensitivity to I/R injury with low autophagy activity in fatty livers. Screening of autophagy-related proteins showed that Atg3 and Atg7 expression levels were marked decreased, whereas calpain 2 expression was upregulated during I/R in fatty livers. Calpain 2 inhibition or knockdown enhanced autophagy and suppressed cell death. Further point mutation experiments revealed that calpain 2 cleaved Atg3 and Atg7 at Atg3Δ92-97 and Atg7Δ344-349, respectively. In vivo and in vitro overexpression of Atg3 or Atg7 enhanced autophagy and suppressed cell death after I/R in fatty livers. Collectively, calpain 2-mediated degradation of Atg3 and Atg7 in fatty livers increases their sensitivity to I/R injury. Increasing autophagy may ameliorate fatty liver damage and represent a valuable method to expand the liver donor pool. PMID:27077802

  18. Dexamethasone-induced autophagy mediates muscle atrophy through mitochondrial clearance

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    Troncoso, Rodrigo; Paredes, Felipe; Parra, Valentina; Gatica, Damián; Vásquez-Trincado, César; Quiroga, Clara; Bravo-Sagua, Roberto; López-Crisosto, Camila; Rodriguez, Andrea E; Oyarzún, Alejandra P; Kroemer, Guido; Lavandero, Sergio

    2014-01-01

    Glucocorticoids, such as dexamethasone, enhance protein breakdown via ubiquitin–proteasome system. However, the role of autophagy in organelle and protein turnover in the glucocorticoid-dependent atrophy program remains unknown. Here, we show that dexamethasone stimulates an early activation of autophagy in L6 myotubes depending on protein kinase, AMPK, and glucocorticoid receptor activity. Dexamethasone increases expression of several autophagy genes, including ATG5, LC3, BECN1, and SQSTM1 and triggers AMPK-dependent mitochondrial fragmentation associated with increased DNM1L protein levels. This process is required for mitophagy induced by dexamethasone. Inhibition of mitochondrial fragmentation by Mdivi-1 results in disrupted dexamethasone-induced autophagy/mitophagy. Furthermore, Mdivi-1 increases the expression of genes associated with the atrophy program, suggesting that mitophagy may serve as part of the quality control process in dexamethasone-treated L6 myotubes. Collectively, these data suggest a novel role for dexamethasone-induced autophagy/mitophagy in the regulation of the muscle atrophy program. PMID:24897381

  19. TFEB-mediated autophagy rescues midbrain dopamine neurons from α-synuclein toxicity

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    Decressac, Mickael; Mattsson, Bengt; Weikop, Pia;

    2013-01-01

    The aggregation of α-synuclein plays a major role in Parkinson disease (PD) pathogenesis. Recent evidence suggests that defects in the autophagy-mediated clearance of α-synuclein contribute to the progressive loss of nigral dopamine neurons. Using an in vivo model of α-synuclein toxicity, we show...

  20. Chaperone-Mediated Autophagy Targets IFNAR1 for Lysosomal Degradation in Free Fatty Acid Treated HCV Cell Culture.

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    Ramazan Kurt

    . Pharmacological inhibitors of lysosomal degradation, such as ammonium chloride and bafilomycin, prevented IFNAR1 degradation in FFA-treated HCV cell culture. Activators of chaperone-mediated autophagy, including 6-aminonicotinamide and nutrient starvation, decreased IFNAR1 levels in Huh-7.5 cells. Co-immunoprecipitation, colocalization and siRNA knockdown experiments revealed that IFNAR1 but not IFNLR1 interacts with HSC70 and LAMP2A, which are core components of chaperone-mediated autophagy (CMA.Our study presents evidence indicating that chaperone-mediated autophagy targets IFNAR1 degradation in the lysosome in FFA-treated HCV cell culture. These results provide a mechanism for why HCV induced autophagy response selectively degrades type I but not the type III IFNAR1.

  1. Carbamazepine suppresses calpain-mediated autophagy impairment after ischemia/reperfusion in mouse livers

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    Kim, Jae-Sung, E-mail: Jae.Kim@surgery.ufl.edu; Wang, Jin-Hee, E-mail: jin-hee.wang@surgery.ufl.edu; Biel, Thomas G., E-mail: Thomas.Biel@surgery.ufl.edu; Kim, Do-Sung, E-mail: do-sung.kim@surgery.med.ufl.edu; Flores-Toro, Joseph A., E-mail: Joseph.Flores-Toro@surgery.ufl.edu; Vijayvargiya, Richa, E-mail: rvijayvargiya@ufl.edu; Zendejas, Ivan, E-mail: ivan.zendejas@surgery.ufl.edu; Behrns, Kevin E., E-mail: Kevin.Behrns@surgery.ufl.edu

    2013-12-15

    Onset of the mitochondrial permeability transition (MPT) plays a causative role in ischemia/reperfusion (I/R) injury. Current therapeutic strategies for reducing reperfusion injury remain disappointing. Autophagy is a lysosome-mediated, catabolic process that timely eliminates abnormal or damaged cellular constituents and organelles such as dysfunctional mitochondria. I/R induces calcium overloading and calpain activation, leading to degradation of key autophagy-related proteins (Atg). Carbamazepine (CBZ), an FDA-approved anticonvulsant drug, has recently been reported to increase autophagy. We investigated the effects of CBZ on hepatic I/R injury. Hepatocytes and livers from male C57BL/6 mice were subjected to simulated in vitro, as well as in vivo I/R, respectively. Cell death, intracellular calcium, calpain activity, changes in autophagy-related proteins (Atg), autophagic flux, MPT and mitochondrial membrane potential after I/R were analyzed in the presence and absence of 20 μM CBZ. CBZ significantly increased hepatocyte viability after reperfusion. Confocal microscopy revealed that CBZ prevented calcium overloading, the onset of the MPT and mitochondrial depolarization. Immunoblotting and fluorometric analysis showed that CBZ blocked calpain activation, depletion of Atg7 and Beclin-1 and loss of autophagic flux after reperfusion. Intravital multiphoton imaging of anesthetized mice demonstrated that CBZ substantially reversed autophagic defects and mitochondrial dysfunction after I/R in vivo. In conclusion, CBZ prevents calcium overloading and calpain activation, which, in turn, suppresses Atg7 and Beclin-1 depletion, defective autophagy, onset of the MPT and cell death after I/R. - Highlights: • A mechanism of carbamazepine (CBZ)-induced cytoprotection in livers is proposed. • Impaired autophagy is a key event contributing to lethal reperfusion injury. • The importance of autophagy is extended and confirmed in an in vivo model. • CBZ is a potential

  2. Carbamazepine suppresses calpain-mediated autophagy impairment after ischemia/reperfusion in mouse livers

    International Nuclear Information System (INIS)

    Onset of the mitochondrial permeability transition (MPT) plays a causative role in ischemia/reperfusion (I/R) injury. Current therapeutic strategies for reducing reperfusion injury remain disappointing. Autophagy is a lysosome-mediated, catabolic process that timely eliminates abnormal or damaged cellular constituents and organelles such as dysfunctional mitochondria. I/R induces calcium overloading and calpain activation, leading to degradation of key autophagy-related proteins (Atg). Carbamazepine (CBZ), an FDA-approved anticonvulsant drug, has recently been reported to increase autophagy. We investigated the effects of CBZ on hepatic I/R injury. Hepatocytes and livers from male C57BL/6 mice were subjected to simulated in vitro, as well as in vivo I/R, respectively. Cell death, intracellular calcium, calpain activity, changes in autophagy-related proteins (Atg), autophagic flux, MPT and mitochondrial membrane potential after I/R were analyzed in the presence and absence of 20 μM CBZ. CBZ significantly increased hepatocyte viability after reperfusion. Confocal microscopy revealed that CBZ prevented calcium overloading, the onset of the MPT and mitochondrial depolarization. Immunoblotting and fluorometric analysis showed that CBZ blocked calpain activation, depletion of Atg7 and Beclin-1 and loss of autophagic flux after reperfusion. Intravital multiphoton imaging of anesthetized mice demonstrated that CBZ substantially reversed autophagic defects and mitochondrial dysfunction after I/R in vivo. In conclusion, CBZ prevents calcium overloading and calpain activation, which, in turn, suppresses Atg7 and Beclin-1 depletion, defective autophagy, onset of the MPT and cell death after I/R. - Highlights: • A mechanism of carbamazepine (CBZ)-induced cytoprotection in livers is proposed. • Impaired autophagy is a key event contributing to lethal reperfusion injury. • The importance of autophagy is extended and confirmed in an in vivo model. • CBZ is a potential

  3. Modulation of deregulated chaperone-mediated autophagy by a phosphopeptide

    OpenAIRE

    Macri, Christophe; Wang, Fengjuan; Tasset, Inmaculada; Schall, Nicolas; Page, Nicolas; Briand, Jean-Paul; Cuervo, Ana Maria; Muller, Sylviane

    2015-01-01

    The P140 peptide, a 21-mer linear peptide (sequence 131–151) generated from the spliceosomal SNRNP70/U1–70K protein, contains a phosphoserine residue at position 140. It significantly ameliorates clinical manifestations in autoimmune patients with systemic lupus erythematosus and enhances survival in MRL/lpr lupus-prone mice. Previous studies showed that after P140 treatment, there is an accumulation of autophagy markers sequestosome 1/p62 and MAP1LC3-II in MRL/lpr B cells, consistent with a ...

  4. Autophagy and cellular senescence mediated by Sox2 suppress malignancy of cancer cells.

    Directory of Open Access Journals (Sweden)

    Yong-Yeon Cho

    Full Text Available Autophagy is a critical cellular process required for maintaining cellular homeostasis in health and disease states, but the molecular mechanisms and impact of autophagy on cancer is not fully understood. Here, we found that Sox2, a key transcription factor in the regulation of the "stemness" of embryonic stem cells and induced-pluripotent stem cells, strongly induced autophagic phenomena, including intracellular vacuole formation and lysosomal activation in colon cancer cells. The activation occurred through Sox2-mediated ATG10 gene expression and resulted in the inhibition of cell proliferation and anchorage-independent colony growth ex vivo and tumor growth in vivo. Further, we found that Sox2-induced-autophagy enhanced cellular senescence by up-regulating tumor suppressors or senescence factors, including p16(INK4a, p21 and phosphorylated p53 (Ser15. Notably, knockdown of ATG10 in Sox2-expressing colon cancer cells restored cancer cell properties. Taken together, our results demonstrated that regulation of autophagy mediated by Sox2 is a mechanism-driven novel strategy to treat human colon cancers.

  5. FGF signalling regulates bone growth through autophagy.

    Science.gov (United States)

    Cinque, Laura; Forrester, Alison; Bartolomeo, Rosa; Svelto, Maria; Venditti, Rossella; Montefusco, Sandro; Polishchuk, Elena; Nusco, Edoardo; Rossi, Antonio; Medina, Diego L; Polishchuk, Roman; De Matteis, Maria Antonietta; Settembre, Carmine

    2015-12-10

    Skeletal growth relies on both biosynthetic and catabolic processes. While the role of the former is clearly established, how the latter contributes to growth-promoting pathways is less understood. Macroautophagy, hereafter referred to as autophagy, is a catabolic process that plays a fundamental part in tissue homeostasis. We investigated the role of autophagy during bone growth, which is mediated by chondrocyte rate of proliferation, hypertrophic differentiation and extracellular matrix (ECM) deposition in growth plates. Here we show that autophagy is induced in growth-plate chondrocytes during post-natal development and regulates the secretion of type II collagen (Col2), the major component of cartilage ECM. Mice lacking the autophagy related gene 7 (Atg7) in chondrocytes experience endoplasmic reticulum storage of type II procollagen (PC2) and defective formation of the Col2 fibrillary network in the ECM. Surprisingly, post-natal induction of chondrocyte autophagy is mediated by the growth factor FGF18 through FGFR4 and JNK-dependent activation of the autophagy initiation complex VPS34-beclin-1. Autophagy is completely suppressed in growth plates from Fgf18(-/-) embryos, while Fgf18(+/-) heterozygous and Fgfr4(-/-) mice fail to induce autophagy during post-natal development and show decreased Col2 levels in the growth plate. Strikingly, the Fgf18(+/-) and Fgfr4(-/-) phenotypes can be rescued in vivo by pharmacological activation of autophagy, pointing to autophagy as a novel effector of FGF signalling in bone. These data demonstrate that autophagy is a developmentally regulated process necessary for bone growth, and identify FGF signalling as a crucial regulator of autophagy in chondrocytes. PMID:26595272

  6. Adenovirus-mediated wild-type PTEN promoting glioma stem/progenitor cells autophagy activity

    OpenAIRE

    ZHAO Yao-dong; Zi-long WEI; Zhang, Quan-Bin; LOU Mei-qing; HUANG, QIANG

    2013-01-01

    Background PTEN is an anti-oncogene frequently inactivating in glioma. The previous study found that PTEN was closely related to cellular autophagy activity. The purpose of this paper is to study whether the inactivation of PTEN in glioma stem/progenitor cells (GSPCs) is correlative with the low autophagic activity in GSPCs. Methods Wild-type PTEN genes were transferred into GSPCs mediated by adenovirus. The autophagic activity in GSPCs before or after the introduction of wild-type PTEN was...

  7. Thymoquinone inhibits autophagy and induces cathepsin-mediated, caspase-independent cell death in glioblastoma cells.

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    Ira O Racoma

    Full Text Available Glioblastoma is the most aggressive and common type of malignant brain tumor in humans, with a median survival of 15 months. There is a great need for more therapies for the treatment of glioblastoma. Naturally occurring phytochemicals have received much scientific attention because many exhibit potent tumor killing action. Thymoquinone (TQ is the bioactive compound of the Nigella sativa seed oil. TQ has anti-oxidant, anti-inflammatory and anti-neoplastic actions with selective cytotoxicity for human cancer cells compared to normal cells. Here, we show that TQ selectively inhibits the clonogenicity of glioblastoma cells as compared to normal human astrocytes. Also, glioblastoma cell proliferation could be impaired by chloroquine, an autophagy inhibitor, suggesting that glioblastoma cells may be dependent on the autophagic pathway for survival. Exposure to TQ caused an increase in the recruitment and accumulation of the microtubule-associated protein light chain 3-II (LC3-II. TQ also caused an accumulation of the LC3-associated protein p62, confirming the inhibition of autophagy. Furthermore, the levels of Beclin-1 protein expression were unchanged, indicating that TQ interferes with a later stage of autophagy. Finally, treatment with TQ induces lysosome membrane permeabilization, as determined by a specific loss of red acridine orange staining. Lysosome membrane permeabilization resulted in a leakage of cathepsin B into the cytosol, which mediates caspase-independent cell death that can be prevented by pre-treatment with a cathepsin B inhibitor. TQ induced apoptosis, as determined by an increase in PI and Annexin V positive cells. However, apoptosis appears to be caspase-independent due to failure of the caspase inhibitor z-VAD-FMK to prevent cell death and absence of the typical apoptosis related signature DNA fragmentation. Inhibition of autophagy is an exciting and emerging strategy in cancer therapy. In this vein, our results describe a

  8. Mimulone-induced autophagy through p53-mediated AMPK/mTOR pathway increases caspase-mediated apoptotic cell death in A549 human lung cancer cells.

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    Hyun-Kyu An

    Full Text Available Anticancer properties and mechanisms of mimulone (MML, C-geranylflavonoid isolated from the Paulownia tomentosa fruits, were firstly elucidated in this study. MML prevented cell proliferation in a dose- and time-dependent way and triggered apoptosis through the extrinsic pathway in A549 human lung adenocarcinoma cells. Furthermore, MML-treated cells displayed autophagic features, such as the formation of autophagic vacuoles, a primary morphological feature of autophagy, and the accumulation of microtubule-associated protein 1 light chain 3 (LC3 puncta, another typical maker of autophagy, as determined by FITC-conjugated immunostaining and monodansylcadaverine (MDC staining, respectively. The expression levels of LC3-I and LC3-II, specific markers of autophagy, were also augmented by MML treatment. Autophagy inhibition by 3-methyladenine (3-MA, pharmacological autophagy inhibitor, and shRNA knockdown of Beclin-1 reduced apoptotic cell death induced by MML. Autophagic flux was not significantly affected by MML treatment and lysosomal inhibitor, chloroquine (CQ suppressed MML-induced autophagy and apoptosis. MML-induced autophagy was promoted by decreases in p53 and p-mTOR levels and increase of p-AMPK. Moreover, inhibition of p53 transactivation by pifithrin-α (PFT-α and knockdown of p53 enhanced induction of autophagy and finally promoted apoptotic cell death. Overall, the results demonstrate that autophagy contributes to the cytotoxicity of MML in cancer cells harboring wild-type p53. This study strongly suggests that MML is a potential candidate for an anticancer agent targeting both autophagy and apoptotic cell death in human lung cancer. Moreover, co-treatment of MML and p53 inhibitor would be more effective in human lung cancer therapy.

  9. Mimulone-induced autophagy through p53-mediated AMPK/mTOR pathway increases caspase-mediated apoptotic cell death in A549 human lung cancer cells.

    Science.gov (United States)

    An, Hyun-Kyu; Kim, Kyoung-Sook; Lee, Ji-Won; Park, Mi-Hyun; Moon, Hyung-In; Park, Shin-Ji; Baik, Ji-Sue; Kim, Cheorl-Ho; Lee, Young-Choon

    2014-01-01

    Anticancer properties and mechanisms of mimulone (MML), C-geranylflavonoid isolated from the Paulownia tomentosa fruits, were firstly elucidated in this study. MML prevented cell proliferation in a dose- and time-dependent way and triggered apoptosis through the extrinsic pathway in A549 human lung adenocarcinoma cells. Furthermore, MML-treated cells displayed autophagic features, such as the formation of autophagic vacuoles, a primary morphological feature of autophagy, and the accumulation of microtubule-associated protein 1 light chain 3 (LC3) puncta, another typical maker of autophagy, as determined by FITC-conjugated immunostaining and monodansylcadaverine (MDC) staining, respectively. The expression levels of LC3-I and LC3-II, specific markers of autophagy, were also augmented by MML treatment. Autophagy inhibition by 3-methyladenine (3-MA), pharmacological autophagy inhibitor, and shRNA knockdown of Beclin-1 reduced apoptotic cell death induced by MML. Autophagic flux was not significantly affected by MML treatment and lysosomal inhibitor, chloroquine (CQ) suppressed MML-induced autophagy and apoptosis. MML-induced autophagy was promoted by decreases in p53 and p-mTOR levels and increase of p-AMPK. Moreover, inhibition of p53 transactivation by pifithrin-α (PFT-α) and knockdown of p53 enhanced induction of autophagy and finally promoted apoptotic cell death. Overall, the results demonstrate that autophagy contributes to the cytotoxicity of MML in cancer cells harboring wild-type p53. This study strongly suggests that MML is a potential candidate for an anticancer agent targeting both autophagy and apoptotic cell death in human lung cancer. Moreover, co-treatment of MML and p53 inhibitor would be more effective in human lung cancer therapy. PMID:25490748

  10. NOX4 mediates cytoprotective autophagy induced by the EGFR inhibitor erlotinib in head and neck cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Sobhakumari, Arya [Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA (United States); Department of Pathology, The University of Iowa, Iowa City, IA (United States); Schickling, Brandon M. [Department of Internal Medicine, The University of Iowa, Iowa City, IA (United States); Love-Homan, Laurie; Raeburn, Ayanna [Department of Pathology, The University of Iowa, Iowa City, IA (United States); Fletcher, Elise V.M. [Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA (United States); Department of Pathology, The University of Iowa, Iowa City, IA (United States); Case, Adam J. [Free Radical and Radiation Biology Program, Department of Radiation Oncology, The University of Iowa, Iowa City, IA (United States); Domann, Frederick E. [Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA (United States); Department of Pathology, The University of Iowa, Iowa City, IA (United States); Free Radical and Radiation Biology Program, Department of Radiation Oncology, The University of Iowa, Iowa City, IA (United States); Holden Comprehensive Cancer Center, University of Iowa Hospitals and Clinics (UIHC), Iowa City, IA (United States); Miller, Francis J. [Department of Internal Medicine, The University of Iowa, Iowa City, IA (United States); Free Radical and Radiation Biology Program, Department of Radiation Oncology, The University of Iowa, Iowa City, IA (United States); Holden Comprehensive Cancer Center, University of Iowa Hospitals and Clinics (UIHC), Iowa City, IA (United States); and others

    2013-11-01

    Most head and neck squamous cell carcinomas (HNSCCs) overexpress epidermal growth factor receptor (EGFR) and EGFR inhibitors are routinely used in the treatment of HNSCC. However, many HNSCC tumors do not respond or become refractory to EGFR inhibitors. Autophagy, which is a stress-induced cellular self-degradation process, has been reported to reduce the efficacy of chemotherapy in various disease models. The purpose of this study is to determine if the efficacy of the EGFR inhibitor erlotinib is reduced by activation of autophagy via NOX4-mediated oxidative stress in HNSCC cells. Erlotinib induced the expression of the autophagy marker LC3B-II and autophagosome formation in FaDu and Cal-27 cells. Inhibition of autophagy by chloroquine and knockdown of autophagy pathway genes Beclin-1 and Atg5 sensitized both cell lines to erlotinib-induced cytotoxicity, suggesting that autophagy may serve as a protective mechanism. Treatment with catalase (CAT) and diphenylene iodonium (DPI) in the presence of erlotinib suppressed the increase in LC3B-II expression in FaDu and Cal-27 cells. Erlotinib increased NOX4 mRNA and protein expression by increasing its promoter activity and mRNA stability in FaDu cells. Knockdown of NOX4 using adenoviral siNOX4 partially suppressed erlotinib-induced LC3B-II expression, while overexpression of NOX4 increased expression of LC3B-II. These studies suggest that erlotinib may activate autophagy in HNSCC cells as a pro-survival mechanism, and NOX4 may play a role in mediating this effect. - Highlights: • Erlotinib increased LC3B-II and autophagosome formation in HNSCC cells. • Inhibition of autophagy sensitized HNSCC cells to erlotinib. • Erlotinib increased NOX4 promoter and 3′UTR luciferase activity. • Manipulating NOX4 decreases or increases autophagy.

  11. NOX4 mediates cytoprotective autophagy induced by the EGFR inhibitor erlotinib in head and neck cancer cells

    International Nuclear Information System (INIS)

    Most head and neck squamous cell carcinomas (HNSCCs) overexpress epidermal growth factor receptor (EGFR) and EGFR inhibitors are routinely used in the treatment of HNSCC. However, many HNSCC tumors do not respond or become refractory to EGFR inhibitors. Autophagy, which is a stress-induced cellular self-degradation process, has been reported to reduce the efficacy of chemotherapy in various disease models. The purpose of this study is to determine if the efficacy of the EGFR inhibitor erlotinib is reduced by activation of autophagy via NOX4-mediated oxidative stress in HNSCC cells. Erlotinib induced the expression of the autophagy marker LC3B-II and autophagosome formation in FaDu and Cal-27 cells. Inhibition of autophagy by chloroquine and knockdown of autophagy pathway genes Beclin-1 and Atg5 sensitized both cell lines to erlotinib-induced cytotoxicity, suggesting that autophagy may serve as a protective mechanism. Treatment with catalase (CAT) and diphenylene iodonium (DPI) in the presence of erlotinib suppressed the increase in LC3B-II expression in FaDu and Cal-27 cells. Erlotinib increased NOX4 mRNA and protein expression by increasing its promoter activity and mRNA stability in FaDu cells. Knockdown of NOX4 using adenoviral siNOX4 partially suppressed erlotinib-induced LC3B-II expression, while overexpression of NOX4 increased expression of LC3B-II. These studies suggest that erlotinib may activate autophagy in HNSCC cells as a pro-survival mechanism, and NOX4 may play a role in mediating this effect. - Highlights: • Erlotinib increased LC3B-II and autophagosome formation in HNSCC cells. • Inhibition of autophagy sensitized HNSCC cells to erlotinib. • Erlotinib increased NOX4 promoter and 3′UTR luciferase activity. • Manipulating NOX4 decreases or increases autophagy

  12. Apoptotic Cell Death Induced by Resveratrol Is Partially Mediated by the Autophagy Pathway in Human Ovarian Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Fangfang Lang

    Full Text Available Resveratrol (trans-3,4,5'-trihydroxystilbene is an active compound in food, such as red grapes, peanuts, and berries. Resveratrol exhibits an anticancer effect on various human cancer cells. However, the mechanism of resveratrol-induced anti-cancer effect at the molecular level remains to be elucidated. In this study, the mechanism underlying the anti-cancer effect of resveratrol in human ovarian cancer cells (OVCAR-3 and Caov-3 was investigated using various molecular biology techniques, such as flow cytometry, western blotting, and RNA interference, with a major focus on the potential role of autophagy in resveratrol-induced apoptotic cell death. We demonstrated that resveratrol induced reactive oxygen species (ROS generation, which triggers autophagy and subsequent apoptotic cell death. Resveratrol induced ATG5 expression and promoted LC3 cleavage. The apoptotic cell death induced by resveratrol was attenuated by both pharmacological and genetic inhibition of autophagy. The autophagy inhibitor chloroquine, which functions at the late stage of autophagy, significantly reduced resveratrol-induced cell death and caspase 3 activity in human ovarian cancer cells. We also demonstrated that targeting ATG5 by siRNA also suppressed resveratrol-induced apoptotic cell death. Thus, we concluded that a common pathway between autophagy and apoptosis exists in resveratrol-induced cell death in OVCAR-3 human ovarian cancer cells.

  13. Autophagy mediated by arginine depletion activation of the nutrient sensor GCN2 contributes to interferon-γ-induced malignant transformation of primary bovine mammary epithelial cells

    Science.gov (United States)

    Xia, X-j; Gao, Y-y; Zhang, J; Wang, L; Zhao, S; Che, Y-y; Ao, C-j; Yang, H-j; Wang, J-q; Lei, L-c

    2016-01-01

    Autophagy has been linked to the regulation of both the prevention and progression of cancer. IFN-γ has been shown to induce autophagy in multiple cell lines in vitro. However, whether IFN-γ can induce autophagy and whether autophagy promotes malignant transformation in healthy lactating bovine mammary epithelial cells (BMECs) remain unclear. Here, we provide the first evidence of the correlation between IFN-γ treatment, autophagy and malignant transformation and of the mechanism underlying IFN-γ-induced autophagy and subsequent malignant transformation in primary BMECs. IFN-γ levels were significantly increased in cattle that received normal long-term dietary corn straw (CS) roughage supplementation. In addition, an increase in autophagy was clearly observed in the BMECs from the mammary tissue of cows expressing high levels of IFN-γ. In vitro, autophagy was clearly induced in primary BMECs by IFN-γ within 24 h. This induced autophagy could subsequently promote dramatic primary BMEC transformation. Furthermore, we found that IFN-γ promoted arginine depletion, activated the general control nonderepressible-2 kinase (GCN2) signalling pathway and resulted in an increase in autophagic flux and the amount of autophagy in BMECs. Overall, our findings are the first to demonstrate that arginine depletion and kinase GCN2 expression mediate IFN-γ-induced autophagy that may promote malignant progression and that immunometabolism, autophagy and cancer are strongly correlated. These results suggest new directions and paths for preventing and treating breast cancer in relation to diet. PMID:27551491

  14. Apoptosis and autophagy induced by pyropheophorbide-α methyl ester-mediated photodynamic therapy in human osteosarcoma MG-63 cells.

    Science.gov (United States)

    Huang, Qiu; Ou, Yun-Sheng; Tao, Yong; Yin, Hang; Tu, Ping-Hua

    2016-06-01

    Pyropheophorbide-α methyl ester (MPPa) was a second-generation photosensitizer with many potential applications. Here, we explored the impact of MPPa-mediated photodynamic therapy (MPPa-PDT) on the apoptosis and autophagy of human osteosarcoma (MG-63) cells as well as the relationships between apoptosis and autophagy of the cells, and investigated the related molecular mechanisms. We found that MPPa-PDT demonstrated the ability to inhibit MG-63 cell viability in an MPPa concentration- and light dose-dependent manner, and to induce apoptosis via the mitochondrial apoptosis pathway. Additionally, MPPa-PDT could also induce autophagy of MG-63 cell. Meanwhile, the ROS scavenger N-acetyl-L-cysteine (NAC) and the Jnk inhibitor SP600125 were found to inhibit the MPPa-PDT-induced autophagy, and NAC could also inhibit Jnk phosphorylation. Furthermore, pretreatment with the autophagy inhibitor 3-methyladenine or chloroquine showed the potential in reducing the apoptosis rate induced by MPPa-PDT in MG-63 cells. Our results indicated that the mitochondrial pathway was involved in MPPa-PDT-induced apoptosis of MG-63 cells. Meanwhile the ROS-Jnk signaling pathway was involved in MPPa-PDT-induced autophagy, which further promoted the apoptosis in MG-63 cells. PMID:27108344

  15. Chaperone-Mediated Autophagy and Mitochondrial Homeostasis in Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Ruixin Yang

    2016-01-01

    Full Text Available Parkinson’s disease (PD, a complex neurodegenerative disorder, is pathologically characterized by the formation of Lewy bodies and loss of dopaminergic neurons in the substantia nigra pars compacta (SNc. Mitochondrial dysfunction is considered to be one of the most important causative mechanisms. In addition, dysfunction of chaperone-mediated autophagy (CMA, one of the lysosomal proteolytic pathways, has been shown to play an important role in the pathogenesis of PD. An exciting and important development is recent finding that CMA and mitochondrial quality control may be linked. This review summarizes the studies revealing the link between autophagy and mitochondrial function. Discussions are focused on the connections between CMA and mitochondrial failure and on the role of MEF2D, a neuronal survival factor, in mediating the regulation of mitochondria in the context of CMA. These new findings highlight the need to further explore the possibility of targeting the MEF2D-mitochondria-CMA network in both understanding the PD pathogenesis and developing novel therapeutic strategies.

  16. Adenovirus-mediated wild-type PTEN promoting glioma stem/progenitor cells autophagy activity

    Directory of Open Access Journals (Sweden)

    ZHAO Yao-dong

    2013-05-01

    Full Text Available Background PTEN is an anti-oncogene frequently inactivating in glioma. The previous study found that PTEN was closely related to cellular autophagy activity. The purpose of this paper is to study whether the inactivation of PTEN in glioma stem/progenitor cells (GSPCs is correlative with the low autophagic activity in GSPCs. Methods Wild-type PTEN genes were transferred into GSPCs mediated by adenovirus. The autophagic activity in GSPCs before or after the introduction of wild-type PTEN was detected by immunocytochemistry, electron microscopy, and Western blotting assay. Results After transfection of wild-type PTEN, a large number of microtuble-associated protein 1 light chain 3 (MAP1LC3-positive granules could be found in the cytoplasm of GSPCs under a confocal microscopy, and these granules were demonstrated to be autophagosomes under an electron microscope. Moreover, the expression of autophagy-related gene Beclin-1 significantly increased after the transfection of wild-type PTEN gene. Conclusion The inactivation of PTEN in GSPCs is one reason of the low autophagic activity of GSPCs.

  17. Activation of RARα induces autophagy in SKBR3 breast cancer cells and depletion of key autophagy genes enhances ATRA toxicity.

    Science.gov (United States)

    Brigger, D; Schläfli, A M; Garattini, E; Tschan, M P

    2015-01-01

    All-trans retinoic acid (ATRA), a pan-retinoic acid receptor (RAR) agonist, is, along with other retinoids, a promising therapeutic agent for the treatment of a variety of solid tumors. On the one hand, preclinical studies have shown promising anticancer effects of ATRA in breast cancer; on the other hand, resistances occurred. Autophagy is a cellular recycling process that allows the degradation of bulk cellular contents. Tumor cells may take advantage of autophagy to cope with stress caused by anticancer drugs. We therefore wondered if autophagy is activated by ATRA in mammary tumor cells and if modulation of autophagy might be a potential novel treatment strategy. Indeed, ATRA induces autophagic flux in ATRA-sensitive but not in ATRA-resistant human breast cancer cells. Moreover, using different RAR agonists as well as RARα-knockdown breast cancer cells, we demonstrate that autophagy is dependent on RARα activation. Interestingly, inhibition of autophagy in breast cancer cells by either genetic or pharmacological approaches resulted in significantly increased apoptosis under ATRA treatment and attenuated epithelial differentiation. In summary, our findings demonstrate that ATRA-induced autophagy is mediated by RARα in breast cancer cells. Furthermore, inhibition of autophagy results in enhanced apoptosis. This points to a potential novel treatment strategy for a selected group of breast cancer patients where ATRA and autophagy inhibitors are applied simultaneously. PMID:26313912

  18. Inducing autophagy

    DEFF Research Database (Denmark)

    Harder, Lea M; Bunkenborg, Jakob; Andersen, Jens S.

    2014-01-01

    Autophagy is a lysosomal-mediated catabolic process, which through degradation of different cytoplasmic components aids in maintaining cellular homeostasis and survival during exposure to extra- or intracellular stresses. Ammonia is a potential toxic and stress-inducing byproduct of glutamine...... catabolism, which has recently been found to induce autophagy in an MTOR independent way and support cancer cell survival. In this study, quantitative phosphoproteomics was applied to investigate the initial signaling events linking ammonia to the induction of autophagy. The MTOR inhibitor rapamycin was used...... as a reference treatment to emphasize the differences between an MTOR-dependent and -independent autophagy-induction. By this means 5901 phosphosites were identified of which 626 were treatment-specific regulated and 175 were coregulated. Investigation of the ammonia-specific regulated sites...

  19. JNK-dependent Atg4 upregulation mediates asperphenamate derivative BBP-induced autophagy in MCF-7 cells

    International Nuclear Information System (INIS)

    N-Benzoyl-O-(N′-(1-benzyloxycarbonyl-4-piperidiylcarbonyl) -D-phenylalanyl)-D-phenylalaninol (BBP), a novel synthesized asperphenamate derivative with the increased solubility, showed growth inhibitory effect on human breast carcinoma MCF-7 cells in a time- and concentration-dependent manner. The growth inhibitory effect of BBP was associated with induction of autophagy, which was demonstrated by the development of acidic vesicular organelles, cleavage of LC3 and upregulation of Atg4 in BBP-treated MCF-7 cells. Since the application of Atg4 siRNA totally blocked the cleavage of LC3, we demonstrated a central role of Atg4 in BBP-induced autophagy. The further studies showed that BBP increased the levels of reactive oxygen species (ROS), and pretreatment with NAC effectively blocked the accumulation of ROS, autophagy and growth inhibition triggered by BBP. Moreover, BBP induced the activation of JNK, and JNK inhibitor SP600125 reversed autophagy, the increase of Atg4 levels, conversion of LC3 and growth inhibition induced by BBP. Knockdown of JNK by siRNA efficiently inhibited ROS production and autophagy, but antioxidant NAC failed to block JNK activation induced by BBP, indicating that JNK activation may be a upstream signaling of ROS and should be a core component in BBP-induced autophagic signaling pathway. These results suggest that BBP produces its growth inhibitory effect through induction of the autophagic cell death in MCF-7 cells, which is modulated by a JNK-dependent Atg4 upregulation involving ROS production. -- Highlights: ► Asperphenamate derivative BBP with increased solubility was synthesized. ► BBP selectively inhibited the growth of human breast tumor cells. ► The growth inhibitory effect of BBP was associated with induction of autophagy. ► JNK-dependent Atg4 upregulation mediated BBP-induced autophagy.

  20. Coupling of HIV-1 Antigen to the Selective Autophagy Receptor SQSTM1/p62 Promotes T-Cell-Mediated Immunity

    Science.gov (United States)

    Andersen, Aram Nikolai; Landsverk, Ole Jørgen; Simonsen, Anne; Bogen, Bjarne; Corthay, Alexandre; Øynebråten, Inger

    2016-01-01

    Vaccines aiming to promote T-cell-mediated immune responses have so far showed limited efficacy, and there is a need for novel strategies. Studies indicate that autophagy plays an inherent role in antigen processing and presentation for CD4+ and CD8+ T cells. Here, we report a novel vaccine strategy based on fusion of antigen to the selective autophagy receptor sequestosome 1 (SQSTM1)/p62. We hypothesized that redirection of vaccine antigen from proteasomal degradation into the autophagy pathway would increase the generation of antigen-specific T cells. A hybrid vaccine construct was designed in which the antigen is fused to the C-terminus of p62, a signaling hub, and a receptor that naturally delivers ubiquitinated cargo for autophagic degradation. Fusion of the human immunodeficiency virus-1 antigen Gagp24 to p62 resulted in efficient antigen delivery into the autophagy pathway. Intradermal immunization of mice revealed that, in comparison to Gagp24 delivered alone, fusion to p62 enhanced the number of Gagp24-specific interferon-γ-producing T cells, including CD8+ T cells. The strategy may also have the potential to modulate the antigenic peptide repertoire. Because p62 and autophagy are highly conserved between species, we anticipate this strategy to be a candidate for the development of T-cell-based vaccines in humans.

  1. Downregulation of protein kinase CK2 activity facilitates tumor necrosis factor-α-mediated chondrocyte death through apoptosis and autophagy.

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    Sung Won Lee

    Full Text Available Despite the numerous studies of protein kinase CK2, little progress has been made in understanding its function in chondrocyte death. Our previous study first demonstrated that CK2 is involved in apoptosis of rat articular chondrocytes. Recent studies have suggested that CK2 downregulation is associated with aging. Thus examining the involvement of CK2 downregulation in chondrocyte death is an urgently required task. We undertook this study to examine whether CK2 downregulation modulates chondrocyte death. We first measured CK2 activity in articular chondrocytes of 6-, 21- and 30-month-old rats. Noticeably, CK2 activity was downregulated in chondrocytes with advancing age. To build an in vitro experimental system for simulating tumor necrosis factor (TNF-α-induced cell death in aged chondrocytes with decreased CK2 activity, chondrocytes were co-treated with CK2 inhibitors and TNF-α. Viability assay demonstrated that CK2 inhibitors facilitated TNF-α-mediated chondrocyte death. Pulsed-field gel electrophoresis, nuclear staining, flow cytometry, TUNEL staining, confocal microscopy, western blot and transmission electron microscopy were conducted to assess cell death modes. The results of multiple assays showed that this cell death was mediated by apoptosis. Importantly, autophagy was also involved in this process, as supported by the appearance of a punctuate LC3 pattern and autophagic vacuoles. The inhibition of autophagy by silencing of autophage-related genes 5 and 7 as well as by 3-methyladenine treatment protected chondrocytes against cell death and caspase activation, indicating that autophagy led to the induction of apoptosis. Autophagic cells were observed in cartilage obtained from osteoarthritis (OA model rats and human OA patients. Our findings indicate that CK2 down regulation facilitates TNF-α-mediated chondrocyte death through apoptosis and autophagy. It should be clarified in the future if autophagy observed is a consequence

  2. Mechanical stress triggers cardiomyocyte autophagy through angiotensin II type 1 receptor-mediated p38MAP kinase independently of angiotensin II.

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    Li Lin

    Full Text Available Angiotensin II (Ang II type 1 (AT1 receptor is known to mediate a variety of physiological actions of Ang II including autophagy. However, the role of AT1 receptor in cardiomyocyte autophagy triggered by mechanical stress still remains elusive. The aim of this study was therefore to examine whether and how AT1 receptor participates in cardiomyocyte autophagy induced by mechanical stresses. A 48-hour mechanical stretch and a 4-week transverse aorta constriction (TAC were imposed to cultured cardiomyocytes of neonatal rats and adult male C57B/L6 mice, respectively, to induce cardiomyocyte hypertrophy prior to the assessment of cardiomyocyte autophagy using LC3b-II. Losartan, an AT1 receptor blocker, but not PD123319, the AT2 inhibitor, was found to significantly reduce mechanical stretch-induced LC3b-II upregulation. Moreover, inhibition of p38MAP kinase attenuated not only mechanical stretch-induced cardiomyocyte hypertrophy but also autophagy. To the contrary, inhibition of ERK and JNK suppressed cardiac hypertrophy but not autophagy. Intriguingly, mechanical stretch-induced autophagy was significantly inhibited by Losartan in the absence of Ang II. Taken together, our results indicate that mechanical stress triggers cardiomyocyte autophagy through AT1 receptor-mediated activation of p38MAP kinase independently of Ang II.

  3. Autophagy plays an important role in Sunitinib-mediated cell death in H9c2 cardiac muscle cells

    International Nuclear Information System (INIS)

    Sunitinib, which is a multitargeted tyrosine-kinase inhibitor, exhibits antiangiogenic and antitumor activity, and extends survival of patients with metastatic renal-cell carcinoma (mRCC) and gastrointestinal stromal tumors (GIST). This molecule has also been reported to be associated with cardiotoxicity at a high frequency, but the mechanism is still unknown. In the present study, we observed that Sunitinib showed high anti-proliferative effect on H9c2 cardiac muscle cells measured by PI staining and the MTT assay. But apoptotic markers (PARP cleavage, caspase 3 cleavage and chromatin condensation) were uniformly negative in H9c2 cells after Sunitinib treatment for 48 h, indicating that another cell death pathway may be involved in Sunitinib-induced cardiotoxicity. Here we found Sunitinib dramatically increased autophagic flux in H9c2 cells. Acidic vesicle fluorescence and high expression of LC3-II in H9c2 cells identified autophagy as a Sunitinib-induced process that might be associated with cytotoxicity. Furthermore, knocking down Beclin 1 by RNA-interference to block autophagy in H9c2 cells revealed that the death rate was decreased when treated with Sunitinib in comparison to control cells. These results confirmed that autophagy plays an important role in Sunitinib-mediated H9c2 cells cytotoxicity. Taken together, the data presented here strongly suggest that autophagy is associated with Sunitinib-induced cardiotoxicity, and that inhibition of autophagy constitutes a viable strategy for reducing Sunitinib-induced cardiomyocyte death thereby alleviating Sunitinib cardiotoxicity.

  4. IFN-gamma-inducible Irga6 mediates host resistance against Chlamydia trachomatis via autophagy.

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    Munir A Al-Zeer

    Full Text Available Chlamydial infection of the host cell induces Gamma interferon (IFNgamma, a central immunoprotector for humans and mice. The primary defense against Chlamydia infection in the mouse involves the IFNgamma-inducible family of IRG proteins; however, the precise mechanisms mediating the pathogen's elimination are unknown. In this study, we identify Irga6 as an important resistance factor against C. trachomatis, but not C. muridarum, infection in IFNgamma-stimulated mouse embryonic fibroblasts (MEFs. We show that Irga6, Irgd, Irgm2 and Irgm3 accumulate at bacterial inclusions in MEFs upon stimulation with IFNgamma, whereas Irgb6 colocalized in the presence or absence of the cytokine. This accumulation triggers a rerouting of bacterial inclusions to autophagosomes that subsequently fuse to lysosomes for elimination. Autophagy-deficient Atg5-/- MEFs and lysosomal acidification impaired cells surrender to infection. Irgm2, Irgm3 and Irgd still localize to inclusions in IFNgamma-induced Atg5-/- cells, but Irga6 localization is disrupted indicating its pivotal role in pathogen resistance. Irga6-deficient (Irga6-/- MEFs, in which chlamydial growth is enhanced, do not respond to IFNgamma even though Irgb6, Irgd, Irgm2 and Irgm3 still localize to inclusions. Taken together, we identify Irga6 as a necessary factor in conferring host resistance by remodelling a classically nonfusogenic intracellular pathogen to stimulate fusion with autophagosomes, thereby rerouting the intruder to the lysosomal compartment for destruction.

  5. Baicalein pretreatment reduces liver ischemia/reperfusion injury via induction of autophagy in rats.

    Science.gov (United States)

    Liu, Anding; Huang, Liang; Guo, Enshuang; Li, Renlong; Yang, Jiankun; Li, Anyi; Yang, Yan; Liu, Shenpei; Hu, Jifa; Jiang, Xiaojing; Dirsch, Olaf; Dahmen, Uta; Sun, Jian

    2016-01-01

    We previously demonstrated that baicalein could protect against liver ischemia/reperfusion (I/R) injury in mice. The exact mechanism of baicalein remains poorly understood. Autophagy plays an important role in protecting against I/R injury. This study was designed to determine whether baicalein could protect against liver I/R injury via induction of autophagy in rats. Baicalein was intraperitoneally injected 1 h before warm ischemia. Pretreatment with baicalein prior to I/R insult significantly blunted I/R-induced elevations of serum aminotransferase levels and significantly improved the histological status of livers. Electron microscopy and expression of the autophagic marker LC3B-II suggested induction of autophagy after baicalein treatment. Moreover, inhibition of the baicalein-induced autophagy using 3-methyladenine (3-MA) worsened liver injury. Furthermore, baicalein treatment increased heme oxygenase (HO)-1 expression, and pharmacological inhibition of HO-1 with tin protoporphyrin IX (SnPP) abolished the baicalein-mediated autophagy and the hepatocellular protection. In primary rat hepatocytes, baicalein-induced autophagy also protected hepatocytes from hypoxia/reoxygenation injury in vitro and the beneficial effect was abrogated by 3-MA or Atg7 siRNA, respectively. Suppression of HO-1 activity by SnPP or HO-1 siRNA prevented the baicalein-mediated autophagy and resulted in increased hepatocellular injury. Collectively, these results suggest that baicalein prevents hepatocellular injury via induction of HO-1-mediated autophagy. PMID:27150843

  6. Inhibition of autophagy suppresses sertraline-mediated primary ciliogenesis in retinal pigment epithelium cells.

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    Eun Sung Kim

    Full Text Available Primary cilia are conserved cellular organelles that regulate diverse signaling pathways. Autophagy is a complex process of cellular degradation and recycling of cytoplasmic proteins and organelles, and plays an important role in cellular homeostasis. Despite its potential importance, the role of autophagy in ciliogenesis is largely unknown. In this study, we identified sertraline as a regulator of autophagy and ciliogenesis. Sertraline, a known antidepressant, induced the growth of cilia and blocked the disassembly of cilia in htRPE cells. Following treatment of sertraline, there was an increase in the number of cells with autophagic puncta and LC3 protein conversion. In addition, both a decrease of ATG5 expression and the treatment of an autophagy inhibitor resulted in the suppression of the sertraline-induced activation of autophagy in htRPE cells. Interestingly, we found that genetic and chemical inhibition of autophagy attenuated the growth of primary cilia in htRPE cells. Taken together, our results suggest that the inhibition of autophagy suppresses sertraline-induced ciliogenesis.

  7. Inhibition of glycogen synthase kinase 3β promotes autophagy to protect mice from acute liver failure mediated by peroxisome proliferator-activated receptor α

    OpenAIRE

    Ren, F.; Zhang, L; Zhang, X; Shi, H; T. Wen; Bai, L.; S. Zheng; Y. Chen; Chen, D.; Li, L.; Duan, Z

    2016-01-01

    Our previous studies have demonstrated that inhibition of glycogen synthase kinase 3β (GSK3β) activity protects mice from acute liver failure (ALF), whereas its protective and regulatory mechanism remains elusive. Autophagy is a recently recognized rudimentary cellular response to inflammation and injury. The aim of the present study was to test the hypothesis that inhibition of GSK3β mediates autophagy to inhibit liver inflammation and protect against ALF. In ALF mice model induced by d-gala...

  8. Autophagy mediates survival of pancreatic tumour-initiating cells in a hypoxic microenvironment.

    Science.gov (United States)

    Rausch, Vanessa; Liu, Li; Apel, Anja; Rettig, Theresa; Gladkich, Jury; Labsch, Sabrina; Kallifatidis, Georgios; Kaczorowski, Adam; Groth, Ariane; Gross, Wolfgang; Gebhard, Martha M; Schemmer, Peter; Werner, Jens; Salnikov, Alexei V; Zentgraf, Hanswalter; Büchler, Markus W; Herr, Ingrid

    2012-07-01

    Involvement of dysregulated autophagy in cancer growth and progression has been shown in different tumour entities, including pancreatic ductal adenocarcinoma (PDA). PDA is an extremely aggressive tumour characterized by a small population of highly therapy-resistant cancer stem cells (CSCs) capable of self-renewal and migration. We examined whether autophagy might be involved in the survival of CSCs despite nutrition and oxygen deprivation typical for the hypoxic tumour microenvironment of PDA. Immunohistochemistry revealed that markers for hypoxia, CSCs and autophagy are co-expressed in patient-derived tissue of PDA. Hypoxia starvation (H/S) enhanced clonogenic survival and migration of established pancreatic cancer cells with stem-like properties (CSC(high)), while pancreatic tumour cells with fewer stem cell markers (CSC(low)) did not survive these conditions. Electron microscopy revealed more advanced autophagic vesicles in CSC(high) cells, which exhibited higher expression of autophagy-related genes under normoxic conditions and relative to CSC(low) cells, as found by RT-PCR and western blot analysis. LC3 was already fully converted to the active LC3-II form in both cell lines, as evaluated by western blot and detection of accumulated GFP-LC3 protein by fluorescence microscopy. H/S increased formation of autophagic and acid vesicles, as well as expression of autophagy-related genes, to a higher extent in CSC(high) cells. Modulation of autophagy by inhibitors and activators resensitized CSC(high) to apoptosis and diminished clonogenicity, spheroid formation, expression of CSC-related genes, migratory activity and tumourigenicity in mice. Our data suggest that enhanced autophagy levels may enable survival of CSC(high) cells under H/S. Interference with autophagy-activating or -inhibiting drugs disturbs the fine-tuned physiological balance of enhanced autophagy in CSC and switches survival signalling to suicide. PMID:22262369

  9. Di-retinoid-pyridinium-ethanolamine (A2E) Accumulation and the Maintenance of the Visual Cycle Are Independent of Atg7-mediated Autophagy in the Retinal Pigmented Epithelium.

    Science.gov (United States)

    Perusek, Lindsay; Sahu, Bhubanananda; Parmar, Tanu; Maeno, Hiroshi; Arai, Eisuke; Le, Yun-Zheng; Subauste, Carlos S; Chen, Yu; Palczewski, Krzysztof; Maeda, Akiko

    2015-11-27

    Autophagy is an evolutionarily conserved catabolic mechanism that relieves cellular stress by removing/recycling damaged organelles and debris through the action of lysosomes. Compromised autophagy has been implicated in many neurodegenerative diseases, including retinal degeneration. Here we examined retinal phenotypes resulting from RPE-specific deletion of the autophagy regulatory gene Atg7 by generating Atg7(flox/flox);VMD2-rtTA-cre+ mice to determine whether autophagy is essential for RPE functions including retinoid recycling. Atg7-deficient RPE displayed abnormal morphology with increased RPE thickness, cellular debris and vacuole formation indicating that autophagy is important in maintaining RPE homeostasis. In contrast, 11-cis-retinal content, ERGs and retinal histology were normal in mice with Atg7-deficient RPE in both fasted and fed states. Because A2E accumulation in the RPE is associated with pathogenesis of both Stargardt disease and age-related macular degeneration (AMD) in humans, deletion of Abca4 was introduced into Atg7(flox/flox);VMD2-rtTA-cre+ mice to investigate the role of autophagy during A2E accumulation. Comparable A2E concentrations were detected in the eyes of 6-month-old mice with and without Atg7 from both Abca4(-/-) and Abca4(+/+) backgrounds. To identify other autophagy-related molecules involved in A2E accumulation, we performed gene expression array analysis on A2E-treated human RPE cells and found up-regulation of four autophagy related genes; DRAM1, NPC1, CASP3, and EIF2AK3/PERK. These observations indicate that Atg7-mediated autophagy is dispensable for retinoid recycling and A2E deposition; however, autophagy plays a role in coping with stress caused by A2E accumulation. PMID:26468292

  10. Autophagy in pulmonary macrophages mediates lung inflammatory injury via NLRP3 inflammasome activation during mechanical ventilation

    OpenAIRE

    Zhang, Yang; Liu, Gongjian; Dull, Randal O; Schwartz, David E; Hu, Guochang

    2014-01-01

    The inflammatory response is a primary mechanism in the pathogenesis of ventilator-induced lung injury. Autophagy is an essential, homeostatic process by which cells break down their own components. We explored the role of autophagy in the mechanisms of mechanical ventilation-induced lung inflammatory injury. Mice were subjected to low (7 ml/kg) or high (28 ml/kg) tidal volume ventilation for 2 h. Bone marrow-derived macrophages transfected with a scrambled or autophagy-related protein 5 smal...

  11. Aspartyl Protease-Mediated Cleavage of BAG6 Is Necessary for Autophagy and Fungal Resistance in Plants.

    Science.gov (United States)

    Li, Yurong; Kabbage, Mehdi; Liu, Wende; Dickman, Martin B

    2016-01-01

    The Bcl-2-associated athanogene (BAG) family is an evolutionarily conserved group of cochaperones that modulate numerous cellular processes. Previously we found that Arabidopsis thaliana BAG6 is required for basal immunity against the fungal phytopathogen Botrytis cinerea. However, the mechanisms by which BAG6 controls immunity are obscure. Here, we address this important question by determining the molecular mechanisms responsible for BAG6-mediated basal resistance. We show that Arabidopsis BAG6 is cleaved in vivo in a caspase-1-like-dependent manner and via a combination of pull-downs, mass spectrometry, yeast two-hybrid assays, and chemical genomics, we demonstrate that BAG6 interacts with a C2 GRAM domain protein (BAGP1) and an aspartyl protease (APCB1), both of which are required for BAG6 processing. Furthermore, fluorescence and transmission electron microscopy established that BAG6 cleavage triggers autophagy in the host that coincides with disease resistance. Targeted inactivation of BAGP1 or APCB1 results in the blocking of BAG6 processing and loss of resistance. Mutation of the cleavage site blocks cleavage and inhibits autophagy in plants; disease resistance is also compromised. Taken together, these results identify a mechanism that couples an aspartyl protease with a molecular cochaperone to trigger autophagy and plant defense, providing a key link between fungal recognition and the induction of cell death and resistance. PMID:26739014

  12. Concanavalin A/IFN-gamma triggers autophagy-related necrotic hepatocyte death through IRGM1-mediated lysosomal membrane disruption.

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    Chih-Peng Chang

    Full Text Available Interferon-gamma (IFN-γ, a potent Th1 cytokine with multiple biological functions, can induce autophagy to enhance the clearance of the invading microorganism or cause cell death. We have reported that Concanavalin A (Con A can cause autophagic cell death in hepatocytes and induce both T cell-dependent and -independent acute hepatitis in immunocompetent and immunodeficient mice, respectively. Although IFN-γ is known to enhance liver injury in Con A-induced hepatitis, its role in autophagy-related hepatocyte death is not clear. In this study we report that IFN-γ can enhance Con A-induced autophagic flux and cell death in hepatoma cell lines. A necrotic cell death with increased lysosomal membrane permeabilization (LMP is observed in Con A-treated hepatoma cells in the presence of IFN-γ. Cathepsin B and L were released from lysosomes to cause cell death. Furthermore, IFN-γ induces immunity related GTPase family M member 1(IRGM1 translocation to lysosomes and prolongs its activity in Con A-treated hepatoma cells. Knockdown of IRGM1 inhibits the IFN-γ/Con A-induced LMP change and cell death. Furthermore, IFN-γ(-/- mice are resistant to Con A-induced autophagy-associated necrotic hepatocyte death. We conclude that IFN-γ enhances Con A-induced autophagic flux and causes an IRGM1-dependent lysosome-mediated necrotic cell death in hepatocytes.

  13. Avian influenza A virus H5N1 causes autophagy-mediated cell death through suppression of mTOR signaling

    Institute of Scientific and Technical Information of China (English)

    Jianhui Ma; Qian Sun; Ruifang Mi; Hongbing Zhang

    2011-01-01

    Of the few avian influenza viruses that have crossed the species barrier to infect humans,the highly pathogenic influenza A (H5N1) strain has claimed the lives of more than half of the infected patients.With largely unknown mechanism of lung injury by H5N1 infection,acute respiratory distress syndrome (ARDS) is the major cause of death among the victims.Here we present the fact that H5N1 caused autophagic cell death through suppression of mTOR signaling.Inhibition of autophagy,either by depletion of autophagy gene Beclinl or by autophagy inhibitor 3-methyladenine (3-MA),significantly reduced H5N1 mediated cell death.We suggest that autophagic cell death may contribute to the development of ARDS in H5N1 influenza patients and inhibition of autophagy could therefore become a novel strategy for the treatment of H5N1 infection.

  14. Inhibition of HIF-1α Affects Autophagy Mediated Glycosylation in Oral Squamous Cell Carcinoma Cells

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    Yi-Ning Li

    2015-01-01

    Full Text Available Purpose. To validate the function of autophagy with the regulation of hypoxia inhibitor-induced glycosylation in oral squamous cell carcinoma cell. Methods. Human Tca8113 cell line was used to detect autophagy and glycosylation related protein expression by western blotting and immunofluorescence with HIF-1α inhibitor. Short interfering RNA (siRNA transfection blocked human ATG12 and ATG1. Results. HIF-1α inhibitor PX-478 reduced the amount of LC3-II and LC3-I in Tca8113 cells. PX-478 decreased the expression of O-GlcNAc and OGT and increased OGA expression. The tendency of O-GlcNAc showed a similar pattern to OGT. PX-478 gradually decreased OGT expression in Tca8113 cells. Protein level of O-GlcNAc and OGT increased in ATG12 and ATG1 depletion. The expression of OGT decreased at first and then rose slowly with the treatment of Atg12 and Atg1 siRNA and PX-478 fluctuant. Autophagy affected the stability of OGT when HIF-1α signaling was blocked. Conclusions. Autophagy reduced by hypoxic stress inhibited. HIF-1α inhibitor decreased glycosylation. OGT became unstable in the absence of autophagy when HIF-1α signaling was blocked.

  15. Autophagy Inhibition Delays Early but Not Late-Stage Metastatic Disease.

    Science.gov (United States)

    Barnard, Rebecca A; Regan, Daniel P; Hansen, Ryan J; Maycotte, Paola; Thorburn, Andrew; Gustafson, Daniel L

    2016-08-01

    The autophagy pathway has been recognized as a mechanism of survival and therapy resistance in cancer, yet the extent of autophagy's function in metastatic progression is still unclear. Therefore, we used murine models of metastatic cancer to investigate the effect of autophagy modulation on metastasis development. Pharmacologic and genetic autophagy inhibition were able to impede cell proliferation in culture, but did not impact the development of experimentally induced 4T1 and B16-F10 metastases. Similarly, autophagy inhibition by adjuvant chloroquine (CQ) treatment did not delay metastasis in an orthotopic 4T1, tumor-resection model. However, neoadjuvant CQ treatment or genetic autophagy inhibition resulted in delayed metastasis development, whereas stimulation of autophagy by trehalose hastened development. Cisplatin was also administered either as a single agent or in combination with CQ. The combination of cisplatin and CQ was antagonistic. The effects of autophagy modulation on metastasis did not appear to be due to alterations in the intrinsic metastatic capability of the cells, as modulating autophagy had no impact on migration, invasion, or anchorage-independent growth in vitro. To explore the possibility of autophagy's influence on the metastatic microenvironment, bone marrow-derived cells (BMDCs), which mediate the establishment of the premetastatic niche, were measured in the lung and in circulation. Trehalose-treated mice had significantly more BMDCs than either vehicle- or CQ-treated mice. Autophagy inhibition may be most useful as a treatment to impede early metastatic development. However, modulating autophagy may also alter the efficacy of platinum-based therapies, requiring caution when considering combination therapies. PMID:27231155

  16. Idarubicin induces mTOR-dependent cytotoxic autophagy in leukemic cells

    International Nuclear Information System (INIS)

    We investigated if the antileukemic drug idarubicin induces autophagy, a process of programmed cellular self-digestion, in leukemic cell lines and primary leukemic cells. Transmission electron microscopy and acridine orange staining demonstrated the presence of autophagic vesicles and intracellular acidification, respectively, in idarubicin-treated REH leukemic cell line. Idarubicin increased punctuation/aggregation of microtubule-associated light chain 3B (LC3B), enhanced the conversion of LC3B-I to autophagosome-associated LC3B-II in the presence of proteolysis inhibitors, and promoted the degradation of the selective autophagic target p62, thus indicating the increase in autophagic flux. Idarubicin inhibited the phosphorylation of the main autophagy repressor mammalian target of rapamycin (mTOR) and its downstream target p70S6 kinase. The treatment with the mTOR activator leucine prevented idarubicin-mediated autophagy induction. Idarubicin-induced mTOR repression was associated with the activation of the mTOR inhibitor AMP-activated protein kinase and down-regulation of the mTOR activator Akt. The suppression of autophagy by pharmacological inhibitors or LC3B and beclin-1 genetic knockdown rescued REH cells from idarubicin-mediated oxidative stress, mitochondrial depolarization, caspase activation and apoptotic DNA fragmentation. Idarubicin also caused mTOR inhibition and cytotoxic autophagy in K562 leukemic cell line and leukocytes from chronic myeloid leukemia patients, but not healthy controls. By demonstrating mTOR-dependent cytotoxic autophagy in idarubicin-treated leukemic cells, our results warrant caution when considering combining idarubicin with autophagy inhibitors in leukemia therapy. - Highlights: • Idarubicin induces autophagy in leukemic cell lines and primary leukemic cells. • Idarubicin induces autophagy by inhibiting mTOR in leukemic cells. • mTOR suppression by idarubicin is associated with AMPK activation and Akt blockade.

  17. Idarubicin induces mTOR-dependent cytotoxic autophagy in leukemic cells

    Energy Technology Data Exchange (ETDEWEB)

    Ristic, Biljana [Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade (Serbia); Bosnjak, Mihajlo [Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade (Serbia); Arsikin, Katarina [Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade (Serbia); Mircic, Aleksandar; Suzin-Zivkovic, Violeta [Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade (Serbia); Bogdanovic, Andrija [Clinic for Hematology, Clinical Centre of Serbia, School of Medicine, University of Belgrade, Belgrade (Serbia); Perovic, Vladimir [Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade (Serbia); Martinovic, Tamara; Kravic-Stevovic, Tamara; Bumbasirevic, Vladimir [Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade (Serbia); Trajkovic, Vladimir, E-mail: vtrajkovic@med.bg.ac.rs [Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade (Serbia); Harhaji-Trajkovic, Ljubica, E-mail: buajk@yahoo.com [Institute for Biological Research, University of Belgrade, Belgrade, Despot Stefan Blvd. 142, 11000 Belgrade (Serbia)

    2014-08-01

    We investigated if the antileukemic drug idarubicin induces autophagy, a process of programmed cellular self-digestion, in leukemic cell lines and primary leukemic cells. Transmission electron microscopy and acridine orange staining demonstrated the presence of autophagic vesicles and intracellular acidification, respectively, in idarubicin-treated REH leukemic cell line. Idarubicin increased punctuation/aggregation of microtubule-associated light chain 3B (LC3B), enhanced the conversion of LC3B-I to autophagosome-associated LC3B-II in the presence of proteolysis inhibitors, and promoted the degradation of the selective autophagic target p62, thus indicating the increase in autophagic flux. Idarubicin inhibited the phosphorylation of the main autophagy repressor mammalian target of rapamycin (mTOR) and its downstream target p70S6 kinase. The treatment with the mTOR activator leucine prevented idarubicin-mediated autophagy induction. Idarubicin-induced mTOR repression was associated with the activation of the mTOR inhibitor AMP-activated protein kinase and down-regulation of the mTOR activator Akt. The suppression of autophagy by pharmacological inhibitors or LC3B and beclin-1 genetic knockdown rescued REH cells from idarubicin-mediated oxidative stress, mitochondrial depolarization, caspase activation and apoptotic DNA fragmentation. Idarubicin also caused mTOR inhibition and cytotoxic autophagy in K562 leukemic cell line and leukocytes from chronic myeloid leukemia patients, but not healthy controls. By demonstrating mTOR-dependent cytotoxic autophagy in idarubicin-treated leukemic cells, our results warrant caution when considering combining idarubicin with autophagy inhibitors in leukemia therapy. - Highlights: • Idarubicin induces autophagy in leukemic cell lines and primary leukemic cells. • Idarubicin induces autophagy by inhibiting mTOR in leukemic cells. • mTOR suppression by idarubicin is associated with AMPK activation and Akt blockade.

  18. Beclin-1-independent autophagy mediates programmed cancer cell death through interplays with endoplasmic reticulum and/or mitochondria in colbat chloride-induced hypoxia.

    Science.gov (United States)

    Sun, Lei; Liu, Ning; Liu, Shan-Shan; Xia, Wu-Yan; Liu, Meng-Yao; Li, Lin-Feng; Gao, Jian-Xin

    2015-01-01

    Autophagy has dual functions in cell survival and death. However, the effects of autophagy on cancer cell survival or death remain controversial. In this study, we show that Autophagy can mediate programmed cell death (PCD) of cancer cells in responding to cobalt chloride (CoCl2)-induced hypoxia in a Beclin-1-independent but autophagy protein 5 (ATG5)-dependent manner. Although ATG5 is not directly induced by CoCl2, its constitutive expression is essential for CoCl2-induced PCD. The ATG5-mediated autophagic PCD requires interplays with endoplasmic reticulum (ER) and/or mitochondria. In this process, ATG5 plays a central role in regulating ER stress protein CCAAT/enhancer-binding protein (C/EBP) homologous protein (CHOP) and mitochondrial protein second mitochondria derived activator of caspases (Smac). Two pathways for autophagic PCD in cancer cells responding to hypoxia have been identified: ATG5/CHOP/Smac pathway and ATG5/Smac pathway, which are probably dependent on the context of cell lines. The former is more potent than the latter for the induction of PCD at the early stage of hypoxia, although the ultimate efficiency of both pathways is comparable. In addition, both pathways may require ATG5-mediated conversion of LC3-I into LC3-II. Therefore, we have defined two autophagy-mediated pathways for the PCD of cancer cells in hypoxia, which are dependent on ATG5, interplayed with ER and mitochondria and tightly regulated by hypoxic status. The findings provide a new evidence that autophagy may inhibit tumor cell proliferation through trigger of PCD, facilitating the development of novel anti-cancer drugs. PMID:26609472

  19. Andrographolide Analogue Induces Apoptosis and Autophagy Mediated Cell Death in U937 Cells by Inhibition of PI3K/Akt/mTOR Pathway.

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    Deepak Kumar

    Full Text Available Current chemotherapeutic agents based on apoptosis induction are lacking in desired efficacy. Therefore, there is continuous effort to bring about new dimension in control and gradual eradication of cancer by means of ever evolving therapeutic strategies. Various forms of PCD are being increasingly implicated in anti-cancer therapy and the complex interplay among them is vital for the ultimate fate of proliferating cells. We elaborated and illustrated the underlying mechanism of the most potent Andrographolide analogue (AG-4 mediated action that involved the induction of dual modes of cell death-apoptosis and autophagy in human leukemic U937 cells.AG-4 induced cytotoxicity was associated with redox imbalance and apoptosis which involved mitochondrial depolarisation, altered apoptotic protein expressions, activation of the caspase cascade leading to cell cycle arrest. Incubation with caspase inhibitor Z-VAD-fmk or Bax siRNA decreased cytotoxic efficacy of AG-4 emphasising critical roles of caspase and Bax. In addition, AG-4 induced autophagy as evident from LC3-II accumulation, increased Atg protein expressions and autophagosome formation. Pre-treatment with 3-MA or Atg 5 siRNA suppressed the cytotoxic effect of AG-4 implying the pro-death role of autophagy. Furthermore, incubation with Z-VAD-fmk or Bax siRNA subdued AG-4 induced autophagy and pre-treatment with 3-MA or Atg 5 siRNA curbed AG-4 induced apoptosis-implying that apoptosis and autophagy acted as partners in the context of AG-4 mediated action. AG-4 also inhibited PI3K/Akt/mTOR pathway. Inhibition of mTOR or Akt augmented AG-4 induced apoptosis and autophagy signifying its crucial role in its mechanism of action.Thus, these findings prove the dual ability of AG-4 to induce apoptosis and autophagy which provide a new perspective to it as a potential molecule targeting PCD for future cancer therapeutics.

  20. Retinoid receptor signaling and autophagy in acute promyelocytic leukemia

    Energy Technology Data Exchange (ETDEWEB)

    Orfali, Nina [Cork Cancer Research Center, University College Cork, Cork (Ireland); Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065, USA. (United States); McKenna, Sharon L. [Cork Cancer Research Center, University College Cork, Cork (Ireland); Cahill, Mary R. [Department of Hematology, Cork University Hospital, Cork (Ireland); Gudas, Lorraine J., E-mail: ljgudas@med.cornell.edu [Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065, USA. (United States); Mongan, Nigel P., E-mail: nigel.mongan@nottingham.ac.uk [Faculty of Medicine and Health Science, School of Veterinary Medicine and Science, University of Nottingham, LE12 5RD (United Kingdom); Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065, USA. (United States)

    2014-05-15

    Retinoids are a family of signaling molecules derived from vitamin A with well established roles in cellular differentiation. Physiologically active retinoids mediate transcriptional effects on cells through interactions with retinoic acid (RARs) and retinoid-X (RXR) receptors. Chromosomal translocations involving the RARα gene, which lead to impaired retinoid signaling, are implicated in acute promyelocytic leukemia (APL). All-trans-retinoic acid (ATRA), alone and in combination with arsenic trioxide (ATO), restores differentiation in APL cells and promotes degradation of the abnormal oncogenic fusion protein through several proteolytic mechanisms. RARα fusion-protein elimination is emerging as critical to obtaining sustained remission and long-term cure in APL. Autophagy is a degradative cellular pathway involved in protein turnover. Both ATRA and ATO also induce autophagy in APL cells. Enhancing autophagy may therefore be of therapeutic benefit in resistant APL and could broaden the application of differentiation therapy to other cancers. Here we discuss retinoid signaling in hematopoiesis, leukemogenesis, and APL treatment. We highlight autophagy as a potential important regulator in anti-leukemic strategies. - Highlights: • Normal and aberrant retinoid signaling in hematopoiesis and leukemia is reviewed. • We suggest a novel role for RARα in the development of X-RARα gene fusions in APL. • ATRA therapy in APL activates transcription and promotes onco-protein degradation. • Autophagy may be involved in both onco-protein degradation and differentiation. • Pharmacologic autophagy induction may potentiate ATRA's therapeutic effects.

  1. Retinoid receptor signaling and autophagy in acute promyelocytic leukemia

    International Nuclear Information System (INIS)

    Retinoids are a family of signaling molecules derived from vitamin A with well established roles in cellular differentiation. Physiologically active retinoids mediate transcriptional effects on cells through interactions with retinoic acid (RARs) and retinoid-X (RXR) receptors. Chromosomal translocations involving the RARα gene, which lead to impaired retinoid signaling, are implicated in acute promyelocytic leukemia (APL). All-trans-retinoic acid (ATRA), alone and in combination with arsenic trioxide (ATO), restores differentiation in APL cells and promotes degradation of the abnormal oncogenic fusion protein through several proteolytic mechanisms. RARα fusion-protein elimination is emerging as critical to obtaining sustained remission and long-term cure in APL. Autophagy is a degradative cellular pathway involved in protein turnover. Both ATRA and ATO also induce autophagy in APL cells. Enhancing autophagy may therefore be of therapeutic benefit in resistant APL and could broaden the application of differentiation therapy to other cancers. Here we discuss retinoid signaling in hematopoiesis, leukemogenesis, and APL treatment. We highlight autophagy as a potential important regulator in anti-leukemic strategies. - Highlights: • Normal and aberrant retinoid signaling in hematopoiesis and leukemia is reviewed. • We suggest a novel role for RARα in the development of X-RARα gene fusions in APL. • ATRA therapy in APL activates transcription and promotes onco-protein degradation. • Autophagy may be involved in both onco-protein degradation and differentiation. • Pharmacologic autophagy induction may potentiate ATRA's therapeutic effects

  2. Receptor Proteins in Selective Autophagy

    Directory of Open Access Journals (Sweden)

    Christian Behrends

    2012-01-01

    Full Text Available Autophagy has long been thought to be an essential but unselective bulk degradation pathway. However, increasing evidence suggests selective autophagosomal turnover of a broad range of substrates. Bifunctional autophagy receptors play a key role in selective autophagy by tethering cargo to the site of autophagosomal engulfment. While the identity of molecular components involved in selective autophagy has been revealed at least to some extent, we are only beginning to understand how selectivity is achieved in this process. Here, we summarize the mechanistic and structural basis of receptor-mediated selective autophagy.

  3. STAT3-dependent TXNDC17 expression mediates Taxol resistance through inducing autophagy in human colorectal cancer cells.

    Science.gov (United States)

    Zhang, Zhongde; Wang, Aihua; Li, Hui; Zhi, Hui; Lu, Feng

    2016-06-10

    Taxol (paclitaxel) is one of the taxane class of anticancer drugs as a first-line chemotherapeutic agent against many cancers including colorectal cancer, breast cancer, non-small cell lung cancer, ovarian cancer and so on. It is verified to induce cytotoxicity in a concentration and time-dependent manner. Numerous novel formulations of Taxol have been remanufactured for better therapeutic effect. Though Taxol works as a common anticancer drug for a long time in clinical practice, drug resistance is a major limitation of its long-term administration. In-depth research on drug resistance is still in progress and researchers have made some achievements, however, the mechanism or key molecule related to Taxol resistance in colorectal cancer still remains to be explored. In the present study, we observed that the high expression of TXNDC17 (thioredoxin domain containing 17) was associated with Taxol resistance in colorectal cancer cells. And TXNDC17 mediated Taxol resistance was related with increased basal autophagy level. Taxol exposure induced high levels of phospho-STAT3 (Tyr 705) and TXNDC17; and increase of basal autophagy in colorectal cancer cells. TXNDC17 overexpression cells obtained Taxol resistance and a high level of autophagy, and it is not surprising that stable downregulation of TXNDC17 accordingly reversed these phenomena. Interestingly, STAT3 could similarly work as TXNDC17 in spite of slighter effect compared to TXNDC17. And it has been proved that phospho-STAT3 (Tyr 705) possesses transcriptional regulation activity through forming dimmers. Many research revealed that transcription factor STAT3 affected more than 1000 gene products, and TXNDC17 is predicted to be a target gene of STAT3 at UCSC database. For the first time, we found STAT3 could bind promoter region of TXNDC17 (-623bp to -58bp relative to the transcription start site (TSS)) for regulating its expression. These results suggest the possibility that TXNDC17 could play an important role

  4. Autophagy Inhibition Enhances the Mitochondrial-Mediated Apoptosis Induced by Mangrove (Avicennia marina) Extract in Human Breast Cancer Cells

    KAUST Repository

    Esau, Luke

    2015-01-10

    %. Conclusion: Our data provide evidence that AM extract triggers ROS-mediated autophagy as well as caspase-independent apoptosis. The results also strengthen the view that concurrent targeting of apoptotic and autophagic pathways may provide effective therapeutic strategy against cancer.

  5. The Autophagy Regulator Rubicon Is a Feedback Inhibitor of CARD9-Mediated Host Innate Immunity

    OpenAIRE

    Yang, Chul-Su; Rodgers, Mary; Min, Chan-Ki; Lee, Jong-Soo; Kingeter, Lara; Lee, June-Yong; Jong, Ambrose; Kramnik, Igor; Lin, Xin; Jung, Jae U.

    2012-01-01

    Assembly of a scaffold consisting of CARD9, BCL10, and MALT1 (CBM complex) is critical for effective signaling by multiple pattern recognition receptors (PRRs) including Dectin and RIG-I. The RUN domain Beclin-1-interacting cysteine-rich-containing Rubicon protein associates constitutively with the Beclin-UVRAG-Vps34 complex under normal conditions to regulate autophagy. Rubicon also interacts with the phagocytic NADPH-oxidase complex upon TLR stimulation to induce potent antimicrobial respon...

  6. Arginine Supplementation Recovered the IFN-γ-Mediated Decrease in Milk Protein and Fat Synthesis by Inhibiting the GCN2/eIF2α Pathway, Which Induces Autophagy in Primary Bovine Mammary Epithelial Cells

    Science.gov (United States)

    Xia, Xiaojing; Che, Yanyi; Gao, Yuanyuan; Zhao, Shuang; Ao, Changjin; Yang, Hongjian; Liu, Juxiong; Liu, Guowen; Han, Wenyu; Wang, Yuping; Lei, Liancheng

    2016-01-01

    During the lactation cycle of the bovine mammary gland, autophagy is induced in bovine mammary epithelial cells (BMECs) as a cellular homeostasis and survival mechanism. Interferon gamma (IFN-γ) is an important antiproliferative and apoptogenic factor that has been shown to induce autophagy in multiple cell lines in vitro. However, it remains unclear whether IFN-γ can induce autophagy and whether autophagy affects milk synthesis in BMECs. To understand whether IFN-γ affects milk synthesis, we isolated and purified primary BMECs and investigated the effect of IFN-γ on milk synthesis in primary BMECs in vitro. The results showed that IFN-γ significantly inhibits milk synthesis and that autophagy was clearly induced in primary BMECs in vitro within 24 h. Interestingly, autophagy was observed following IFN-γ treatment, and the inhibition of autophagy can improve milk protein and milk fat synthesis. Conversely, upregulation of autophagy decreased milk synthesis. Furthermore, mechanistic analysis confirmed that IFN-γ mediated autophagy by depleting arginine and inhibiting the general control nonderepressible-2 kinase (GCN2)/eukaryotic initiation factor 2α (eIF2α) signaling pathway in BMECs. Then, it was found that arginine supplementation could attenuate IFN-γ-induced autophagy and recover milk synthesis to some extent. These findings may not only provide a novel measure for preventing the IFN-γ-induced decrease in milk quality but also a useful therapeutic approach for IFN-γ-associated breast diseases in other animals and humans. PMID:27025389

  7. Bystander autophagy mediated by radiation-induced exosomal miR-7-5p in non-targeted human bronchial epithelial cells.

    Science.gov (United States)

    Song, Man; Wang, Yu; Shang, Zeng-Fu; Liu, Xiao-Dan; Xie, Da-Fei; Wang, Qi; Guan, Hua; Zhou, Ping-Kun

    2016-01-01

    Radiation-induced bystander effect (RIBE) describes a set of biological effects in non-targeted cells that receive bystander signals from the irradiated cells. RIBE brings potential hazards to adjacent normal tissues in radiotherapy, and imparts a higher risk than previously thought. Excessive release of some substances from irradiated cells into extracellular microenvironment has a deleterious effect. For example, cytokines and reactive oxygen species have been confirmed to be involved in RIBE process via extracellular medium or gap junctions. However, RIBE-mediating signals and intercellular communication pathways are incompletely characterized. Here, we first identified a set of differentially expressed miRNAs in the exosomes collected from 2 Gy irradiated human bronchial epithelial BEP2D cells, from which miR-7-5p was found to induce autophagy in recipient cells. This exosome-mediated autophagy was significantly attenuated by miR-7-5p inhibitor. Moreover, our data demonstrated that autophagy induced by exosomal miR-7-5p was associated with EGFR/Akt/mTOR signaling pathway. Together, our results support the involvement of secretive exosomes in propagation of RIBE signals to bystander cells. The exosomes-containing miR-7-5p is a crucial mediator of bystander autophagy. PMID:27417393

  8. Acetylation Targets the M2 Isoform of Pyruvate Kinase for Degradation through Chaperone-Mediated Autophagy and Promotes Tumor Growth

    Science.gov (United States)

    Lv, Lei; Li, Dong; Zhao, Di; Lin, Ruiting; Chu, Yajing; Zhang, Heng; Zha, Zhengyu; Liu, Ying; Li, Zi; Xu, Yanping; Wang, Gang; Huang, Yiran; Xiong, Yue; Guan, Kun-Liang; Lei, Qun-Ying

    2016-01-01

    SUMMARY Most tumor cells take up more glucose than normal cells but metabolize glucose via glycolysis even in the presence of normal levels of oxygen, a phenomenon known as the Warburg effect. Tumor cells commonly express the embryonic M2 isoform of pyruvate kinase (PKM2) that may contribute to the metabolism shift from oxidative phosphorylation to aerobic glycolysis and tumorigenesis. Here we show that PKM2 is acetylated on lysine 305 and that this acetylation is stimulated by high glucose concentration. PKM2 K305 acetylation decreases PKM2 enzyme activity and promotes its lysosomal-dependent degradation via chaperone-mediated autophagy (CMA). Acetylation increases PKM2 interaction with HSC70, a chaperone for CMA, and association with lysosomes. Ectopic expression of an acetylation mimetic K305Q mutant accumulates glycolytic intermediates and promotes cell proliferation and tumor growth. These results reveal an acetylation regulation of pyruvate kinase and the link between lysine acetylation and CMA. PMID:21700219

  9. Oxyphenisatin acetate (NSC 59687) triggers a cell starvation response leading to autophagy, mitochondrial dysfunction, and autocrine TNFα-mediated apoptosis

    International Nuclear Information System (INIS)

    Oxyphenisatin (3,3-bis(4-hydroxyphenyl)-1H-indol-2-one) and several structurally related molecules have been shown to have in vitro and in vivo antiproliferative activity. This study aims to confirm and extend mechanistic studies by focusing on oxyphenisatin acetate (OXY, NSC 59687), the pro-drug of oxyphenisatin. Results confirm that OXY inhibits the growth of the breast cancer cell lines MCF7, T47D, HS578T, and MDA-MB-468. This effect is associated with selective inhibition of translation accompanied by rapid phosphorylation of the nutrient sensing eukaryotic translation initiation factor 2α (eIF2α) kinases, GCN2 and PERK. This effect was paralleled by activation of AMP-activated protein kinase (AMPK) combined with reduced phosphorylation of the mammalian target of rapamycin (mTOR) substrates p70S6K and 4E-BP1. Microarray analysis highlighted activation of pathways involved in apoptosis induction, autophagy, RNA/protein metabolism, starvation responses, and solute transport. Pathway inhibitor combination studies suggested a role for AMPK/mTOR signaling, de novo transcription and translation, reactive oxygen species (ROS)/glutathione metabolism, calcium homeostasis and plasma membrane Na+/K+/Ca2+ transport in activity. Further examination confirmed that OXY treatment was associated with autophagy, mitochondrial dysfunction, and ROS generation. Additionally, treatment was associated with activation of both intrinsic and extrinsic apoptotic pathways. In the estrogen receptor (ER) positive MCF7 and T47D cells, OXY induced TNFα expression and TNFR1 degradation, indicating autocrine receptor-mediated apoptosis in these lines. Lastly, in an MCF7 xenograft model, OXY delivered intraperitoneally inhibited tumor growth, accompanied by phosphorylation of eIF2α and degradation of TNFR1. These data suggest that OXY induces a multifaceted cell starvation response, which ultimately induces programmed cell death. The mechanistic basis for oxyphenisatin acetate anti

  10. C1q/TNF-Related Protein 9 (CTRP9) attenuates hepatic steatosis via the autophagy-mediated inhibition of endoplasmic reticulum stress.

    Science.gov (United States)

    Jung, Tae Woo; Hong, Ho Cheol; Hwang, Hwan-Jin; Yoo, Hye Jin; Baik, Sei Hyun; Choi, Kyung Mook

    2015-12-01

    C1q/TNF-Related Protein (CTRP) 9, the closest paralog of adiponectin, has been reported to protect against diet-induced obesity and non-alcoholic fatty liver disease (NAFLD). However, the underlying mechanism has not been fully elucidated. We explored the protective effect of CTRP9 against hepatic steatosis and apoptosis, and identified the mechanisms through autophagy and endoplasmic reticulum (ER) stress using in vitro and in vivo experiments. Treating HepG2 cells with human recombinant CTRP9 significantly ameliorated palmitate- or tunicamycin-induced dysregulation of lipid metabolism, caspase 3 activity and chromatin condensation, which lead to reduction of hepatic triglyceride (TG) accumulation. CTRP9 treatment induced autophagy markers including LC3 conversion, P62 degradation, Beclin1 and ATG7 through AMPK phosphorylation in human primary hepatocytes. Furthermore, CTRP9 decreased palmitate- or tunicamycin-induced ER stress markers, such as eIF2α, CHOP and IRE-1, in HepG2 cells. Compound C, an AMPK inhibitor, and 3 methyladenine (3 MA), an autophagy inhibitor, canceled the effects of CTRP9 on ER stress, apoptosis and hepatic steatosis. In the livers of HFD-fed mice, adenovirus-mediated CTRP9 overexpression significantly induced AMPK phosphorylation and autophagy, whereas suppressed ER stress markers. In addition, both SREBP1-mediated lipogenic gene expression and apoptosis were significantly attenuated, which result in improvement in hepatic steatosis by overexpression of CTRP9. These results demonstrate that CTRP9 alleviates hepatic steatosis through relief of ER stress via the AMPK-mediated induction of autophagy. PMID:26419929

  11. Ramalin-Mediated Apoptosis Is Enhanced by Autophagy Inhibition in Human Breast Cancer Cells.

    Science.gov (United States)

    Lee, Eunyoung; Lee, Chung Gi; Yim, Joung-Han; Lee, Hong-Kum; Pyo, Suhkneung

    2016-03-01

    Breast cancer, the most commonly diagnosed cancer in women worldwide, is treated in various ways. Ramalin is a chemical compound derived from the Antarctic lichen Ramalina terebrata and is known to exhibit antioxidant and antiinflammatory activities. However, its effect on breast cancer cells remains unknown. We examined the ability of ramalin to induce apoptosis and its mechanisms in MCF-7 and MDA-MB-231 human breast cancer cell lines. Ramalin inhibited cell growth and induced apoptosis in both cell lines in a concentration-dependent manner. By upregulating Bax and downregulating Bcl-2, ramalin caused cytochrome c and apoptosis-inducing factor to be released from the mitochondria into the cytosol, thus activating the mitochondrial apoptotic pathway. In addition, activated caspase-8 and caspase-9 were detected in both types of cells exposed to ramalin, whereas ramalin activated caspase-3 only in the MDA-MB-231 cells. Ramalin treatment also increased the levels of LC3-II and p62. Moreover, the inhibition of autophagy by 3-methyladenine or Atg5 siRNA significantly enhanced ramalin-induced apoptosis, which was accompanied by a decrease in Bcl-2 levels and an increase in Bax levels. Therefore, autophagy appears to be activated as a protective mechanism against apoptosis in cancer cells exposed to ramalin. These findings suggest that ramalin is a potential anticancer agent for the treatment of patients with non-invasive or invasive breast cancer. PMID:26676298

  12. Induction of autophagy by Imatinib sequesters Bcr-Abl in autophagosomes and down-regulates Bcr-Abl protein.

    LENUS (Irish Health Repository)

    Elzinga, Baukje M

    2013-06-01

    Chronic Myeloid Leukemia (CML) is a disease of hematopoietic stem cells which harbor the chimeric gene Bcr-Abl. Expression levels of this constitutively active tyrosine kinase are critical for response to tyrosine kinase inhibitor treatment and also disease progression, yet the regulation of protein stability is poorly understood. We have previously demonstrated that imatinib can induce autophagy in Bcr-Abl expressing cells. Autophagy has been associated with the clearance of large macromolecular signaling complexes and abnormal proteins, however, the contribution of autophagy to the turnover of Bcr-Abl protein in imatinib treated cells is unknown. In this study, we show that following imatinib treatment, Bcr-Abl is sequestered into vesicular structures that co-localize with the autophagy marker LC3 or GABARAP. This association is inhibited by siRNA mediated knockdown of autophagy regulators (Beclin 1\\/ATG7). Pharmacological inhibition of autophagy also reduced Bcr-Abl\\/LC3 co-localization in both K562 and CML patient cells. Bcr-Abl protein expression was reduced with imatinib treatment. Inhibition of both autophagy and proteasome activity in imatinib treated cells was required to restore Bcr-Abl protein levels to those of untreated cells. This ability to down-regulate Bcr-Abl protein levels through the induction of autophagy may be an additional and important feature of the activity of imatinib.

  13. Epigallocatechin-gallate (EGCG) regulates autophagy in human retinal pigment epithelial cells: A potential role for reducing UVB light-induced retinal damage

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chao-Peng; Yao, Jin; Tao, Zhi-Fu; Li, Xiu-Miao; Jiang, Qin, E-mail: jqin710@vip.sina.com; Yan, Biao, E-mail: yanbiao1982@hotmail.com

    2013-09-06

    Highlights: •UVB irradiation induces RPE autophagy. •EGCG treatment represses UVB-mediated autophagy. •EGCG regulates UVB-mediated autophagy through mTOR signaling pathway. •EGCG sensitizes RPE cells to UVB-induced damage in an autophagy-dependent manner. -- Abstract: Autophagy is an intracellular catabolic process involved in protein and organelle degradation via the lysosomal pathway that has been linked in the pathogenesis of age-related macular degeneration (AMD). UVB irradiation-mediated degeneration of the macular retinal pigment epithelial (RPE) cells is an important hallmark of AMD, which is along with the change in RPE autophagy. Thus, pharmacological manipulation of RPE autophagy may offer an alternative therapeutic target in AMD. Here, we found that epigallocatechin-3-gallate (EGCG), a polyphenolic compound from green tea, plays a regulatory role in UVB irradiation-induced autophagy in RPE cells. UVB irradiation results in a marked increase in the amount of LC3-II protein in a dose-dependent manner. EGCG administration leads to a significant reduction in the formation of LC3-II and autophagosomes. mTOR signaling activation is required for EGCG-induced LC3-II formation, as evidenced by the fact that EGCG-induced LC3-II formation is significantly impaired by rapamycin administration. Moreover, EGCG significantly alleviates the toxic effects of UVB irradiation on RPE cells in an autophagy-dependent manner. Collectively, our study reveals a novel role of EGCG in RPE autophagy. EGCG may be exploited as a potential therapeutic reagent for the treatment of pathological conditions associated with abnormal autophagy.

  14. Epigallocatechin-gallate (EGCG) regulates autophagy in human retinal pigment epithelial cells: A potential role for reducing UVB light-induced retinal damage

    International Nuclear Information System (INIS)

    Highlights: •UVB irradiation induces RPE autophagy. •EGCG treatment represses UVB-mediated autophagy. •EGCG regulates UVB-mediated autophagy through mTOR signaling pathway. •EGCG sensitizes RPE cells to UVB-induced damage in an autophagy-dependent manner. -- Abstract: Autophagy is an intracellular catabolic process involved in protein and organelle degradation via the lysosomal pathway that has been linked in the pathogenesis of age-related macular degeneration (AMD). UVB irradiation-mediated degeneration of the macular retinal pigment epithelial (RPE) cells is an important hallmark of AMD, which is along with the change in RPE autophagy. Thus, pharmacological manipulation of RPE autophagy may offer an alternative therapeutic target in AMD. Here, we found that epigallocatechin-3-gallate (EGCG), a polyphenolic compound from green tea, plays a regulatory role in UVB irradiation-induced autophagy in RPE cells. UVB irradiation results in a marked increase in the amount of LC3-II protein in a dose-dependent manner. EGCG administration leads to a significant reduction in the formation of LC3-II and autophagosomes. mTOR signaling activation is required for EGCG-induced LC3-II formation, as evidenced by the fact that EGCG-induced LC3-II formation is significantly impaired by rapamycin administration. Moreover, EGCG significantly alleviates the toxic effects of UVB irradiation on RPE cells in an autophagy-dependent manner. Collectively, our study reveals a novel role of EGCG in RPE autophagy. EGCG may be exploited as a potential therapeutic reagent for the treatment of pathological conditions associated with abnormal autophagy

  15. Autophagy and ubiquitin-mediated proteolysis may not be involved in the degradation of spermatozoon mitochondria in mouse and porcine early embryos.

    Science.gov (United States)

    Jin, Yong-Xun; Zheng, Zhong; Yu, Xian-Feng; Zhang, Jia-Bao; Namgoong, Suk; Cui, Xiang-Shun; Hyun, Sang-Hwan; Kim, Nam-Hyung

    2016-02-01

    The mitochondrial genome is maternally inherited in animals, despite the fact that paternal mitochondria enter oocytes during fertilization. Autophagy and ubiquitin-mediated degradation are responsible for the elimination of paternal mitochondria in Caenorhabditis elegans; however, the involvement of these two processes in the degradation of paternal mitochondria in mammals is not well understood. We investigated the localization patterns of light chain 3 (LC3) and ubiquitin in mouse and porcine embryos during preimplantation development. We found that LC3 and ubiquitin localized to the spermatozoon midpiece at 3 h post-fertilization, and that both proteins were colocalized with paternal mitochondria and removed upon fertilization during the 4-cell stage in mouse and the zygote stage in porcine embryos. Sporadic paternal mitochondria were present beyond the morula stage in the mouse, and paternal mitochondria were restricted to one blastomere of 4-cell embryos. An autophagy inhibitor, 3-methyladenine (3-MA), did not affect the distribution of paternal mitochondria compared with the positive control, while an autophagy inducer, rapamycin, accelerated the removal of paternal mitochondria compared with the control. After the intracytoplasmic injection of intact spermatozoon into mouse oocytes, LC3 and ubiquitin localized to the spermatozoon midpiece, but remnants of undegraded paternal mitochondria were retained until the blastocyst stage. Our results show that paternal mitochondria colocalize with autophagy receptors and ubiquitin and are removed after in vitro fertilization, but some remnants of sperm mitochondrial sheath may persist up to morula stage after intracytoplasmic spermatozoon injection (ICSI). PMID:25513816

  16. Inhalation of titanium dioxide induces endoplasmic reticulum stress-mediated autophagy and inflammation in mice.

    Science.gov (United States)

    Yu, Kyeong-Nam; Sung, Jae Hyuck; Lee, Somin; Kim, Ji-Eun; Kim, Sanghwa; Cho, Won-Young; Lee, Ah Young; Park, Soo Jin; Lim, Joohyun; Park, Changhoon; Chae, Chanhee; Lee, Jin Kyu; Lee, Jinkyu; Kim, Jun-Sung; Cho, Myung-Haing

    2015-11-01

    Titanium dioxide (TiO2) nanoparticles are widely used in cosmetics, sunscreen, electronics, drug delivery systems, and diverse bio-application fields. In the workplace, the primary exposure route for TiO2 nanoparticles is inhalation through the respiratory system. Because TiO2 nanoparticles have different physiological properties, in terms of size and bioactivity, their toxic effects in the respiratory system must be determined. In this study, to determine the toxic effect of inhaled TiO2 nanoparticles in the lung and the underlying mechanism, we used a whole-body chamber inhalation system to expose A/J mice to TiO2 nanoparticles for 28 days. During the experiments, the inhaled TiO2 nanoparticles were characterized using a cascade impactor and transmission electron microscopy. After inhalation of the TiO2 nanoparticles, hyperplasia and inflammation were observed in a TiO2 dose-dependent manner. To determine the biological mechanism of the toxic response in the lung, we examined endoplasmic reticulum (ER) and mitochondria in lung. The ER and mitochondria were disrupted and dysfunctional in the TiO2-exposed lung leading to abnormal autophagy. In summary, we assessed the potential risk of TiO2 nanoparticles in the respiratory system, which contributed to our understanding of the mechanism underlining TiO2 nanoparticle toxicity in the lung. PMID:26253354

  17. Cadmium induces autophagy through ROS-dependent activation of the LKB1-AMPK signaling in skin epidermal cells

    International Nuclear Information System (INIS)

    Cadmium is a toxic heavy metal which is environmentally and occupationally relevant. The mechanisms underlying cadmium-induced autophagy are not yet completely understood. The present study shows that cadmium induces autophagy, as demonstrated by the increase of LC3-II formation and the GFP-LC3 puncta cells. The induction of autophagosomes was directly visualized by electron microscopy in cadmium-exposed skin epidermal cells. Blockage of LKB1 or AMPK by siRNA transfection suppressed cadmium-induced autophagy. Cadmium-induced autophagy was inhibited in dominant-negative AMPK-transfected cells, whereas it was accelerated in cells transfected with the constitutively active form of AMPK. mTOR signaling, a negative regulator of autophagy, was downregulated in cadmium-exposed cells. In addition, cadmium generated reactive oxygen species (ROS) at relatively low levels, and caused poly(ADP-ribose) polymerase-1 (PARP) activation and ATP depletion. Inhibition of PARP by pharmacological inhibitors or its siRNA transfection suppressed ATP reduction and autophagy in cadmium-exposed cells. Furthermore, cadmium-induced autophagy signaling was attenuated by either exogenous addition of catalase and superoxide dismutase, or by overexpression of these enzymes. Consequently, these results suggest that cadmium-mediated ROS generation causes PARP activation and energy depletion, and eventually induces autophagy through the activation of LKB1-AMPK signaling and the down-regulation of mTOR in skin epidermal cells. - Highlights: → Cadmium, a toxic heavy metal, induces autophagic cell death through ROS-dependent activation of the LKB1-AMPK signaling. → Cadmium generates intracellular ROS at low levels and this leads to severe DNA damage and PARP activation, resulting in ATP depletion, which are the upstream events of LKB1-AMPK-mediated autophagy. → This novel finding may contribute to further understanding of cadmium-mediated diseases.

  18. Trastuzumab, but Not Pertuzumab, Dysregulates HER2 Signaling to Mediate Inhibition of Autophagy and Increase in Reactive Oxygen Species Production in Human Cardiomyocytes.

    Science.gov (United States)

    Mohan, Nishant; Shen, Yi; Endo, Yukinori; ElZarrad, M Khair; Wu, Wen Jin

    2016-06-01

    Dysregulation of autophagy has been implicated in various cardiovascular diseases. Trastuzumab, a humanized monoclonal antibody, binds to HER2 domain IV and is approved for the treatment of HER2-positive breast cancer. Trastuzumab therapy is associated with considerable cardiotoxicity, the mechanism of which remains unclear. HER2 signaling plays a pivotal role in cardiomyocyte development and survival and is essential for the prevention of cardiomyopathy. However, a direct link has not been confirmed between trastuzumab-induced cardiomyopathy and impaired HER2 signaling. Our data reveal a novel mechanism by which trastuzumab dysregulates HER2 signaling and impairs basal autophagic process in human primary cardiomyocytes. Specifically, trastuzumab treatment leads to the phosphorylation of HER1-Y845 and HER2-Y1248 and the activation of Erk. This in turn results in upregulation of mTOR signaling pathway and subsequently inhibition of autophagy in primary cardiomyocytes and C57BL/6 mice. Trastuzumab-induced downregulation of autophagy is further supported by the fact that trastuzumab treatment reduces protein levels of autophagosome-associated signaling molecules such as Atg 5-12, Atg 7, Atg 14, and Beclin 1. We further demonstrated that trastuzumab-mediated inhibition of autophagy resulted in the increased production of reactive oxygen species (ROS) in cardiomyocytes. Pertuzumab, another anti-HER2 therapeutic mAb binding to HER2 domain II, fails to modulate HER2 signaling and is unable to inhibit autophagy and to increase ROS production in cardiomyocytes. This study provides novel mechanistic insights into trastuzumab-induced cardiotoxicity, which may assist in formulating novel approaches for clinical management of trastuzumab-induced cardiomyopathy. Mol Cancer Ther; 15(6); 1321-31. ©2016 AACR. PMID:27197303

  19. Enhancement in efferocytosis of oxidized low-density lipoprotein-induced apoptotic RAW264.7 cells through Sirt1-mediated autophagy.

    Science.gov (United States)

    Liu, Baoxin; Zhang, Buchun; Guo, Rong; Li, Shuang; Xu, Yawei

    2014-03-01

    Macrophages play a key role in atherosclerotic plaque formation and rupture. These phagocytic cells are important in the scavenging of modified lipoproteins, unwanted or dead cells and cellular debris through efferocytosis. Sirtuin1 (Sirt1), a member of the conserved sirtuin family and a key regulator in the progression of atherosclerosis exerts protective effects by regulating autophagy, a well-known survival mechanism. Inhibition of autophagy may also result in defective efferocytosis. This study aimed to investigate the effect of Sirt1 on the efferocytosis of oxidized low-density lipoprotein (ox-LDL)-induced apoptotic RAW264.7 cells through upregulation of autophagy. The apoptotic cells were incubated with high and low concentrations of Sirt1 activator resveratrol (RSV) and Sirt1 inhibitor nicotinamide (NAM) as well as autophagy inhibitor 3-methyl-adenine (3-MA) + low concentration RSV. Apoptosis was determined by flow cytometry (FCM) of annexin-V/propidium iodide (AV/PI) dual staining. Total proteins were extracted and protein levels were detected through western blot analysis. The ox-LDL uptake and efferocytosis of apoptotic RAW264.7 cells were detected by oil red O staining and calculation of the phagocytic index of apoptotic RAW264.7 cells. The expression of Sirt1 and autophagy marker proteins was simultaneously increased with the stimulation of low concentration RSV (all P<0.05) and decreased in low and high NAM groups (all P<0.05), compared with the control group. Efferocytosis was highest in the low concentration RSV group (P<0.001) and relatively lower in the low and high concentration NAM groups (both P<0.05) compared with the control group, which was similar to the change in the expression of Sirt1 and autophagy marker proteins. The results showed that the efferocytosis of apoptotic RAW264.7 cells was significantly improved with the upregulation of Sirt1‑mediated autophagy. Therefore, Sirt1 may serve as a novel therapeutic target for the treatment of

  20. Hsp90 regulates processing of NF-κB2 p100 involving protection of NF-κB-inducing kinase (NIK) from autophagy-mediated degradation

    Institute of Scientific and Technical Information of China (English)

    Guoliang Qing; Pengrong Yan; Zhaoxia Qu; Hudan Liu; Gutian Xiao

    2007-01-01

    NF-κB-inducing kinase (NIK) is required for NF-κB activation based on the processing of NF-κB2 p100. Here we report a novel mechanism of NIK regulation involving the chaperone 90 kDa heat shock protein (Hsp90) and autophagy.Functional inhibition of lisp90 by the anti-tumor agent geldanamycin (GA) efficiently disrupts its interaction with NIK,resulting in NIK degradation and subsequent blockage of p100 processing. Surprisingly, GA-induced NIK degradation is mediated by autophagy, but largely independent of the ubiquitin-proteasome system. Hsp90 seems to be specifically involved in the folding/stabilization of NIK protein, because GA inhibition does not affect NIK mRNA transcription and translation. Furthermore, Hsp90 is not required for NIK-mediated recruitment of the α subunit of IκB kinase to p100, a key step in induction of p100 processing. These findings define an alternative mechanism for Hsp90 client degradation and identify a novel function of autophagy in NF-κB regulation. These findings also suggest a new therapeutic strategy for diseases associated with p100 processing.

  1. Autophagy in 5-Fluorouracil Therapy in Gastrointestinal Cancer: Trends and Challenges

    Institute of Scientific and Technical Information of China (English)

    Jia-Cheng Tang; Yi-Li Feng; Xiao Liang; Xiu-Jun Cai

    2016-01-01

    Objective: 5-Fluorouracil (5-FU)-based combination therapies are standard treatments for gastrointestinal cancer, where the modulation of autophagy is becoming increasingly important in offering effective treatment for patients in clinical practice.This review focuses on the role of autophagy in 5-FU-induced tumor suppression and cancer therapy in the digestive system.Data Sources: All articles published in English from 1996 to date those assess the synergistic effect ofautophagy and 5-FU in gastrointestinal cancer therapy were identified through a systematic online search by use of PubMed.The search terms were "autophagy" and "5-FU" and ("colorectal cancer" or"hepatocellular carcinoma" or"pancreatic adenocarcinoma" or"esophageal cancer" or"gallbladder carcinoma" or "gastric cancer").Study Selection: Critical reviews on relevant aspects and original articles reporting in vitro and/or in vivo results regarding the efficiency ofautophagy and 5-FU in gastrointestinal cancer therapy were reviewed, analyzed, and summarized.The exclusion criteria for the articles were as follows: (1) new materials (e.g., nanomaterial)-induced autophagy;(2) clinical and experimental studies on diagnostic and/or prognostic biomarkers in digestive system cancers;and (3) immunogenic cell death for anticancer chemotherapy.Results: Most cell and animal experiments showed inhibition ofautophagy by either pharmacological approaches or via genetic silencing of autophagy regulatory gene, resulting in a promotion of 5-FU-induced cancer cells death.Meanwhile, autophagy also plays a pro-death role and may mediate cell death in certain cancer cells where apoptosis is defective or difficult to induce.The dual role of autophagy complicates the use of autophagy inhibitor or inducer in cancer chemotherapy and generates inconsistency to an extent in clinic trials.Conclusion: Autophagy might be a therapeutic target that sensitizes the 5-FU treatment in gastrointestinal cancer.

  2. Autophagy-independent enhancing effects of Beclin 1 on cytotoxicity of ovarian cancer cells mediated by proteasome inhibitors

    International Nuclear Information System (INIS)

    The ubiquitin-proteasome system and macroautophagy (hereafter referred to autophagy) are two complementary pathways for protein degradation. Emerging evidence suggests that proteasome inhibition might be a promising approach for tumor therapy. Accumulating data suggest that autophagy is activated as a compensatory mechanism upon proteasome activity is impaired. Autophagy activation was measured using acridine orange staining and LC3 transition. Cell viability and apoptosis were measured using MTT assay and flow cytometry, respectively. Beclin 1 expression vectors or shRNA against Beclin 1 (shBeclin 1) were transfected to investigate the role of Beclin 1 in autophagy activation and cytotoxicity of ovarian cancer cells induced by proteasome inhibitors. Proteasome inhibitors suppressed proliferation and induced autophagy in ovarian cancer cells. Neither phosphoinositide 3-kinase (PI3K) inhibitors nor shRNA against Beclin 1 could abolish the formation of acidic vacuoles and the processing of LC3 induced by proteasome inhibitors. Moreover, Beclin 1 overexpression enhanced anti-proliferative effects of proteasome inhibitors in ovarian cancer cells. For the first time, the current study demonstrated that proteasome inhibitors induced PI3K and Beclin 1-independent autophagy in ovarian cancer cells. In addition, this study revealed autophagy-independent tumor suppressive effects of Beclin 1 in ovarian cancer cells

  3. Inhibition of autophagy ameliorates pulmonary microvascular dilation and PMVECs excessive proliferation in rat experimental hepatopulmonary syndrome

    Science.gov (United States)

    Xu, Duo; Chen, Bing; Gu, Jianteng; Chen, Lin; Belguise, Karine; Wang, Xiaobo; Yi, Bin; Lu, Kaizhi

    2016-01-01

    Hepatopulmonary syndrome (HPS) is a defective liver-induced pulmonary vascular disorder with massive pulmonary microvascular dilation and excessive proliferation of pulmonary microvascular endothelial cells (PMVECs). Growing evidence suggests that autophagy is involved in pulmonary diseases, protectively or detrimentally. Thus, it is interesting and important to explore whether autophagy might be involved in and critical in HPS. In the present study, we report that autophagy was activated in common bile duct ligation (CBDL) rats and cultured pulmonary PMVECs induced by CBDL rat serum, two accepted in vivo and in vitro experimental models of HPS. Furthermore, pharmacological inhibition of autophagy with 3-methyladenine (3-MA) significantly alleviated pathological alterations and typical symptom of HPS in CBDL rats in vivo, and consistently 3-MA significantly attenuated the CBDL rat serum-induced excessive proliferation of PMVECs in vitro. All these changes mediated by 3-MA might explain the observed prominent improvement of pulmonary appearance, edema, microvascular dilatation and arterial oxygenation in vivo. Collectively, these results suggest that autophagy activation may play a critical role in the pathogenesis of HPS, and autophagy inhibition may have a therapeutic potential for this disease. PMID:27480323

  4. Hydrogen-rich saline mediates neuroprotection through the regulation of endoplasmic reticulum stress and autophagy under hypoxia-ischemia neonatal brain injury in mice.

    Science.gov (United States)

    Bai, Xuemei; Liu, Song; Yuan, Lin; Xie, Yunkai; Li, Tong; Wang, Lingxiao; Wang, Xueer; Zhang, Tiantian; Qin, Shucun; Song, Guohau; Ge, Li; Wang, Zhen

    2016-09-01

    Hydrogen as a new medical gas exerts organ-protective effects through regulating oxidative stress, inflammation and apoptosis. Multiple lines of evidence reveal the protective effects of hydrogen in various models of brain injury. However, the exact mechanism underlying this protective effect of hydrogen against hypoxic-ischemic brain damage (HIBD) is not fully understood. The present study was designed to investigate whether hydrogen-rich saline (HS) attenuates HIBD in neonatal mice and whether the observed protection is associated with reduced endoplasmic reticulum (ER) stress and regulated autophagy. The results showed that HS treatment significantly improved brain edema and decreased infarct volume. Furthermore, HS significantly attenuated HIBD-induced ER stress responses, including the decreased expression of glucose-regulated protein 78, C/EBP homologous protein, and down-regulated transcription factor. Additionally, we demonstrated that HS induced autophagy, including increased LC3B and Beclin-1 expression and decreased phosphorylation of mTOR and Stat3, as well as phosphorylation of ERK. Taken together, HS exerts neuroprotection against HIBD in neonatal mouse, mediated in part by reducing ER stress and increasing autophagy machinery. PMID:27317636

  5. Sodium Butyrate Induces Endoplasmic Reticulum Stress and Autophagy in Colorectal Cells: Implications for Apoptosis.

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    Jintao Zhang

    Full Text Available Butyrate, a short-chain fatty acid derived from dietary fiber, inhibits proliferation and induces cell death in colorectal cancer cells. However, clinical trials have shown mixed results regarding the anti-tumor activities of butyrate. We have previously shown that sodium butyrate increases endoplasmic reticulum stress by altering intracellular calcium levels, a well-known autophagy trigger. Here, we investigated whether sodium butyrate-induced endoplasmic reticulum stress mediated autophagy, and whether there was crosstalk between autophagy and the sodium butyrate-induced apoptotic response in human colorectal cancer cells.Human colorectal cancer cell lines (HCT-116 and HT-29 were treated with sodium butyrate at concentrations ranging from 0.5-5mM. Cell proliferation was assessed using MTT tetrazolium salt formation. Autophagy induction was confirmed through a combination of Western blotting for associated proteins, acridine orange staining for acidic vesicles, detection of autolysosomes (MDC staining, and electron microscopy. Apoptosis was quantified by flow cytometry using standard annexinV/propidium iodide staining and by assessing PARP-1 cleavage by Western blot.Sodium butyrate suppressed colorectal cancer cell proliferation, induced autophagy, and resulted in apoptotic cell death. The induction of autophagy was supported by the accumulation of acidic vesicular organelles and autolysosomes, and the expression of autophagy-associated proteins, including microtubule-associated protein II light chain 3 (LC3-II, beclin-1, and autophagocytosis-associated protein (Atg3. The autophagy inhibitors 3-methyladenine (3-MA and chloroquine inhibited sodium butyrate induced autophagy. Furthermore, sodium butyrate treatment markedly enhanced the expression of endoplasmic reticulum stress-associated proteins, including BIP, CHOP, PDI, and IRE-1a. When endoplasmic reticulum stress was inhibited by pharmacological (cycloheximide and mithramycin and genetic

  6. Autophagy Has a Beneficial Role in Relieving Cigarette Smoke-Induced Apoptotic Death in Human Gingival Fibroblasts

    Science.gov (United States)

    Kim, Moon-Soo; Yun, Jeong-Won; Park, Jin-Ho; Park, Bong-Wook; Kang, Young-Hoon; Hah, Young-Sool; Hwang, Sun-Chul; Woo, Dong Kyun; Byun, June-Ho

    2016-01-01

    The deleterious role of cigarette smoke has long been documented in various human diseases including periodontal complications. In this report, we examined this adverse effect of cigarette smoke on human gingival fibroblasts (HGFs) which are critical not only in maintaining gingival tissue architecture but also in mediating immune responses. As well documented in other cell types, we also observed that cigarette smoke promoted cellular reactive oxygen species in HGFs. And we found that this cigarette smoke-induced oxidative stress reduced HGF viability through inducing apoptosis. Our results indicated that an increased Bax/Bcl-xL ratio and resulting caspase activation underlie the apoptotic death in HGFs exposed to cigarette smoke. Furthermore, we detected that cigarette smoke also triggered autophagy, an integrated cellular stress response. Interesting, a pharmacological suppression of the cigarette smoke-induced autophagy led to a further reduction in HGF viability while a pharmacological promotion of autophagy increased the viability of HGFs with cigarette smoke exposures. These findings suggest a protective role for autophagy in HGFs stressed with cigarette smoke, highlighting that modulation of autophagy can be a novel therapeutic target in periodontal complications with cigarette smoke.

  7. Cocaine-Mediated Autophagy in Astrocytes Involves Sigma 1 Receptor, PI3K, mTOR, Atg5/7, Beclin-1 and Induces Type II Programed Cell Death.

    Science.gov (United States)

    Cao, Lu; Walker, Mary P; Vaidya, Naveen K; Fu, Mingui; Kumar, Santosh; Kumar, Anil

    2016-09-01

    Cocaine, a commonly used drug of abuse, has been shown to cause neuropathological dysfunction and damage in the human brain. However, the role of autophagy in this process is not defined. Autophagy, generally protective in nature, can also be destructive leading to autophagic cell death. This study was designed to investigate whether cocaine induces autophagy in the cells of CNS origin. We employed astrocyte, the most abundant cell in the CNS, to define the effects of cocaine on autophagy. We measured levels of the autophagic marker protein LC3II in SVGA astrocytes after exposure with cocaine. The results showed that cocaine caused an increase in LC3II level in a dose- and time-dependent manner, with the peak observed at 1 mM cocaine after 6-h exposure. This result was also confirmed by detecting LC3II in SVGA astrocytes using confocal microscopy and transmission electron microscopy. Next, we sought to explore the mechanism by which cocaine induces the autophagic response. We found that cocaine-induced autophagy was mediated by sigma 1 receptor, and autophagy signaling proteins p-mTOR, Atg5, Atg7, and p-Bcl-2/Beclin-1 were also involved, and this was confirmed by using selective inhibitors and small interfering RNAs (siRNAs). In addition, we found that chronic treatment with cocaine resulted in cell death, which is caspase-3 independent and can be ameliorated by autophagy inhibitor. Therefore, this study demonstrated that cocaine induces autophagy in astrocytes and is associated with autophagic cell death. PMID:26243186

  8. Bozepinib, a novel small antitumor agent, induces PKR-mediated apoptosis and synergizes with IFNα triggering apoptosis, autophagy and senescence

    Directory of Open Access Journals (Sweden)

    Marchal JA

    2013-10-01

    Full Text Available Juan Antonio Marchal,1,2 Esther Carrasco,1 Alberto Ramirez,1,3 Gema Jiménez,1,2 Carmen Olmedo,4 Macarena Peran,1,3 Ahmad Agil,5 Ana Conejo-García,6 Olga Cruz-López,6 Joaquin María Campos,6 María Ángel García4,7 1Biopathology and Regenerative Medicine Institute, Centre for Biomedical Research, 2Department of Human Anatomy and Embryology, Faculty of Medicine, University of Granada, Granada, 3Department of Health Sciences, University of Jaén, Jaén, 4Experimental Surgery Research Unit, Virgen de las Nieves University Hospital, Granada, 5Department of Pharmacology and Neurosciences Institute, Faculty of Medicine, 6Department of Pharmaceutical and Organic Chemistry, Faculty of Pharmacy, University of Granada, Granada, 7Department of Oncology, Virgen de las Nieves University Hospital, Granada, Spain Abstract: Bozepinib [(RS-2,6-dichloro-9-[1-(p-nitrobenzenesulfonyl-1,2,3,5-tetrahydro-4,1- benzoxazepin-3-yl]-9H-purine] is a potent antitumor compound that is able to induce apoptosis in breast cancer cells. In the present study, we show that bozepinib also has antitumor activity in colon cancer cells, showing 50% inhibitory concentration (IC50 values lower than those described for breast cancer cells and suggesting great potential of this synthetic drug in the treatment of cancer. We identified that the double-stranded RNA-dependent protein kinase (PKR is a target of bozepinib, being upregulated and activated by the drug. However, p53 was not affected by bozepinib, and was not necessary for induction of apoptosis in either breast or colon cancer cells. In addition, the efficacy of bozepinib was improved when combined with the interferon-alpha (IFNα cytokine, which enhanced bozepinib-induced apoptosis with involvement of protein kinase PKR. Moreover, we report here, for the first time, that in combined therapy, IFNα induces a clear process of autophagosome formation, and prior treatment with chloroquine, an autophagy inhibitor, is able to

  9. Insulin-degrading enzyme secretion from astrocytes is mediated by an autophagy-based unconventional secretory pathway in Alzheimer disease.

    Science.gov (United States)

    Son, Sung Min; Cha, Moon-Yong; Choi, Heesun; Kang, Seokjo; Choi, Hyunjung; Lee, Myung-Shik; Park, Sun Ah; Mook-Jung, Inhee

    2016-05-01

    The secretion of proteins that lack a signal sequence to the extracellular milieu is regulated by their transition through the unconventional secretory pathway. IDE (insulin-degrading enzyme) is one of the major proteases of amyloid beta peptide (Aβ), a presumed causative molecule in Alzheimer disease (AD) pathogenesis. IDE acts in the extracellular space despite having no signal sequence, but the underlying mechanism of IDE secretion extracellularly is still unknown. In this study, we found that IDE levels were reduced in the cerebrospinal fluid (CSF) of patients with AD and in pathology-bearing AD-model mice. Since astrocytes are the main cell types for IDE secretion, astrocytes were treated with Aβ. Aβ increased the IDE levels in a time- and concentration-dependent manner. Moreover, IDE secretion was associated with an autophagy-based unconventional secretory pathway, and depended on the activity of RAB8A and GORASP (Golgi reassembly stacking protein). Finally, mice with global haploinsufficiency of an essential autophagy gene, showed decreased IDE levels in the CSF in response to an intracerebroventricular (i.c.v.) injection of Aβ. These results indicate that IDE is secreted from astrocytes through an autophagy-based unconventional secretory pathway in AD conditions, and that the regulation of autophagy is a potential therapeutic target in addressing Aβ pathology. PMID:26963025

  10. Autophagy regulates chlorpyrifos-induced apoptosis in SH-SY5Y cells

    International Nuclear Information System (INIS)

    Recent studies have shown that up-regulation of autophagy may be a tractable therapeutic intervention for clearing disease-causing proteins, including α-synuclein, ubiquitin, and other misfolded or aggregated proteins in pesticide-induced neurodegeneration. In a previous study, we reported that chlorpyrifos (CPF)-induced mitochondria-dependent apoptosis is mediated through reactive oxygen species in SH-SY5Y cells. In this study, we explored a novel pharmacotherapeutic approach to prevent CPF neurotoxicity involving the regulation of autophagy. We investigated the modulation of CPF-induced apoptosis according to autophagy regulation. We found that CPF induced apoptosis in SH-SY5Y cells, as demonstrated by the activation of caspase-3 and nuclear condensation. In addition, we observed that cells treated with CPF underwent autophagic cell death by monitoring the expression of LC3-II and p62. Pretreatment with the autophagy inducer rapamycin significantly enhanced the cell viability of CPF-exposed cells, and the enhancement of cell viability was partially due to alleviation of CPF-induced apoptosis via a decrease in levels of cleaved caspase-3. Specifically, rapamycin pretreatment decreased Bax and increased Bcl-2 expression in mitochondria. In addition, rapamycin significantly decreased cytochrome c release in from mitochondria into the cytosol. However, pretreatment of cells with the autophagy inhibitor, 3-methyladenine (3MA), remarkably increased CPF toxicity in these cells; this with correlated with increased expression of Bax and decreased expression of Bcl-2 in mitochondria. Our results suggest that CPF-induced cytotoxicity is modified by autophagy regulation and that rapamycin protects against CPF-induced apoptosis by enhancing autophagy. Pharmacologic induction of autophagy by rapamycin may be a useful treatment strategy in neurodegenerative disorders. - Highlights: ► Chlorpyrifos (CPF) is cytotoxic to SH-SY5Y cells ► CPF-induced cytotoxicity is mediated by

  11. Autophagy regulates chlorpyrifos-induced apoptosis in SH-SY5Y cells

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Hyeon [Department of Pharmacology, College of Medicine, Hanyang University (Korea, Republic of); Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul (Korea, Republic of); Lee, Jeong Eun [Department of Pharmacology, College of Medicine, Hanyang University (Korea, Republic of); Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Shin, In Chul [Department of Pharmacology, College of Medicine, Hanyang University (Korea, Republic of); Koh, Hyun Chul, E-mail: hckoh@hanyang.ac.kr [Department of Pharmacology, College of Medicine, Hanyang University (Korea, Republic of); Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul (Korea, Republic of)

    2013-04-01

    Recent studies have shown that up-regulation of autophagy may be a tractable therapeutic intervention for clearing disease-causing proteins, including α-synuclein, ubiquitin, and other misfolded or aggregated proteins in pesticide-induced neurodegeneration. In a previous study, we reported that chlorpyrifos (CPF)-induced mitochondria-dependent apoptosis is mediated through reactive oxygen species in SH-SY5Y cells. In this study, we explored a novel pharmacotherapeutic approach to prevent CPF neurotoxicity involving the regulation of autophagy. We investigated the modulation of CPF-induced apoptosis according to autophagy regulation. We found that CPF induced apoptosis in SH-SY5Y cells, as demonstrated by the activation of caspase-3 and nuclear condensation. In addition, we observed that cells treated with CPF underwent autophagic cell death by monitoring the expression of LC3-II and p62. Pretreatment with the autophagy inducer rapamycin significantly enhanced the cell viability of CPF-exposed cells, and the enhancement of cell viability was partially due to alleviation of CPF-induced apoptosis via a decrease in levels of cleaved caspase-3. Specifically, rapamycin pretreatment decreased Bax and increased Bcl-2 expression in mitochondria. In addition, rapamycin significantly decreased cytochrome c release in from mitochondria into the cytosol. However, pretreatment of cells with the autophagy inhibitor, 3-methyladenine (3MA), remarkably increased CPF toxicity in these cells; this with correlated with increased expression of Bax and decreased expression of Bcl-2 in mitochondria. Our results suggest that CPF-induced cytotoxicity is modified by autophagy regulation and that rapamycin protects against CPF-induced apoptosis by enhancing autophagy. Pharmacologic induction of autophagy by rapamycin may be a useful treatment strategy in neurodegenerative disorders. - Highlights: ► Chlorpyrifos (CPF) is cytotoxic to SH-SY5Y cells ► CPF-induced cytotoxicity is mediated by

  12. Melatonin-Mediated Intracellular Insulin during 2-Deoxy-d-glucose Treatment Is Reduced through Autophagy and EDC3 Protein in Insulinoma INS-1E Cells

    Directory of Open Access Journals (Sweden)

    Han Sung Kim

    2016-01-01

    Full Text Available 2-DG triggers glucose deprivation without altering other nutrients or metabolic pathways and then activates autophagy via activation of AMPK and endoplasmic reticulum (ER stress. We investigated whether 2-DG reduced intracellular insulin increased by melatonin via autophagy/EDC3 in insulinoma INS-1E cells. p-AMPK and GRP78/BiP level were significantly increased by 2-DG in the presence/absence of melatonin, but IRE1α level was reduced in 2-DG treatment. Levels of p85α, p110, p-Akt (Ser473, Thr308, and p-mTOR (Ser2481 were also significantly reduced by 2-DG in the presence/absence of melatonin. Mn-SOD increased with 2-DG plus melatonin compared to groups treated with/without melatonin alone. Bcl-2 was decreased and Bax increased with 2-DG plus melatonin. LC3II level increased with 2-DG treatment in the presence/absence of melatonin. Intracellular insulin production increased in melatonin plus 2-DG but reduced in treatment with 2-DG with/without melatonin. EDC3 was increased by 2-DG in the presence/absence of melatonin. Rapamycin, an mTOR inhibitor, increased GRP78/BiP and EDC3 levels in a dose-dependent manner and subsequently resulted in a decrease in intracellular production of insulin. These results suggest that melatonin-mediated insulin synthesis during 2-DG treatment involves autophagy and EDC3 protein in rat insulinoma INS-1E cells and subsequently results in a decrease in intracellular production of insulin.

  13. 14-Deoxy-11,12-didehydroandrographolide induces DDIT3-dependent endoplasmic reticulum stress-mediated autophagy in T-47D breast carcinoma cells.

    Science.gov (United States)

    Tan, Heng Kean; Muhammad, Tengku Sifzizul Tengku; Tan, Mei Lan

    2016-06-01

    14-Deoxy-11,12-didehydroandrographolide (14-DDA), a major diterpenoid isolated from Andrographis paniculata (Burm.f.) Nees, is known to be cytotoxic and elicits a non-apoptotic cell death in T-47D breast carcinoma cells. In this study, the mechanistic toxicology properties of 14-DDA in T-47D cells were further investigated. 14-DDA is found to induce the formation of endoplasmic reticulum (ER) vacuoles and autophagosomes, with concurrent upregulation of LC3-II in the breast carcinoma cells. It stimulated an increase in cytosolic calcium concentration and caused a collapse in mitochondrial membrane potential in these cells. In addition, both DDIT3 and GADD45A, molecules implicated in ER stress pathway, were significantly upregulated. DDIT3 knockdown suppressed the formation of both ER vacuoles and autophagosomes, indicating that 14-DDA-induced ER stress and autophagy is dependent on this transcription factor. Collectively, it is possible that GADD45A/p38 MAPK/DDIT3 pathway is involved in the 14-DDA-induced ER-stress-mediated autophagy in T-47D cells. PMID:27049118

  14. Naringin induces autophagy-mediated growth inhibition by downregulating the PI3K/Akt/mTOR cascade via activation of MAPK pathways in AGS cancer cells.

    Science.gov (United States)

    Raha, Suchismita; Yumnam, Silvia; Hong, Gyeong Eun; Lee, Ho Jeong; Saralamma, Venu Venkatarame Gowda; Park, Hyeon-Soo; Heo, Jeong Doo; Lee, Sang Joon; Kim, Eun Hee; Kim, Jin-A; Kim, Gon Sup

    2015-09-01

    Naringin, one of the major bioflavonoid of Citrus, has been demonstrated as potential anticancer agent. However, the underlying anticancer mechanism still needs to be explored further. This study investigated the inhibitory effect of Naringin on human AGS cancer cells. AGS cell proliferation was inhibited by Naringin in a dose- and time-dependent manner. Naringin did not induce apoptotic cell death, determined by no DNA fragmentation and the reduced Bax/Bcl-xL ratio. Growth inhibitory role of Naringin was observed by western blot analysis demonstrating downregulation of PI3K/Akt/mTOR cascade with an upregulated p21CIPI/WAFI. Formation of cytoplasmic vacuoles and autophagosomes were observed in Naringin-treated AGS cells, further confirmed by the activation of autophagic proteins Beclin 1 and LC3B with a significant phosphorylation of mitogen activated protein kinases (MAPKs). Collectively, our observed results determined that anti-proliferative activity of Naringin in AGS cancer cells is due to suppression of PI3K/Akt/mTOR cascade via induction of autophagy with activated MAPKs. Thus, the present finding suggests that Naringin induced autophagy- mediated growth inhibition shows potential as an alternative therapeutic agent for human gastric carcinoma. PMID:26201693

  15. Inhibition of mTOR-dependent autophagy sensitizes leukemic cells to cytarabine-induced apoptotic death.

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    Mihajlo Bosnjak

    Full Text Available The present study investigated the role of autophagy, a cellular self-digestion process, in the cytotoxicity of antileukemic drug cytarabine towards human leukemic cell lines (REH, HL-60, MOLT-4 and peripheral blood mononuclear cells from leukemic patients. The induction of autophagy was confirmed by acridine orange staining of intracellular acidic vesicles, electron microscopy visualization of autophagic vacuoles, as well as by the increase in autophagic proteolysis and autophagic flux, demonstrated by immunoblot analysis of p62 downregulation and LC3-I conversion to autophagosome-associated LC3-II in the presence of proteolysis inhibitors, respectively. Moreover, the expression of autophagy-related genes Atg4, Atg5 and Atg7 was stimulated by cytarabine in REH cells. Cytarabine reduced the phosphorylation of the major negative regulator of autophagy, mammalian target of rapamycin (mTOR, and its downstream target p70S6 kinase in REH cells, which was associated with downregulation of mTOR activator Akt and activation of extracellular signal- regulated kinase. Cytarabine had no effect on the activation of mTOR inhibitor AMP-activated protein kinase. Leucine, an mTOR activator, reduced both cytarabine-induced autophagy and cytotoxicity. Accordingly, pharmacological downregulation of autophagy with bafilomycin A1 and chloroquine, or RNA interference-mediated knockdown of LC3β or p62, markedly increased oxidative stress, mitochondrial depolarization, caspase activation and subsequent DNA fragmentation and apoptotic death in cytarabine-treated REH cells. Cytarabine also induced mTOR-dependent cytoprotective autophagy in HL-60 and MOLT-4 leukemic cell lines, as well as primary leukemic cells, but not normal leukocytes. These data suggest that the therapeutic efficiency of cytarabine in leukemic patients could be increased by the inhibition of the mTOR-dependent autophagic response.

  16. Dopamine Oxidation and Autophagy

    Directory of Open Access Journals (Sweden)

    Patricia Muñoz

    2012-01-01

    Full Text Available The molecular mechanisms involved in the neurodegenerative process of Parkinson's disease remain unclear. Currently, there is a general agreement that mitochondrial dysfunction, α-synuclein aggregation, oxidative stress, neuroinflammation, and impaired protein degradation are involved in the neurodegeneration of dopaminergic neurons containing neuromelanin in Parkinson's disease. Aminochrome has been proposed to play an essential role in the degeneration of dopaminergic neurons containing neuromelanin by inducing mitochondrial dysfunction, oxidative stress, the formation of neurotoxic α-synuclein protofibrils, and impaired protein degradation. Here, we discuss the relationship between the oxidation of dopamine to aminochrome, the precursor of neuromelanin, autophagy dysfunction in dopaminergic neurons containing neuromelanin, and the role of dopamine oxidation to aminochrome in autophagy dysfunction in dopaminergic neurons. Aminochrome induces the following: (i the formation of α-synuclein protofibrils that inactivate chaperone-mediated autophagy; (ii the formation of adducts with α- and β-tubulin, which induce the aggregation of the microtubules required for the fusion of autophagy vacuoles and lysosomes.

  17. Loss of autophagy in hypothalamic POMC neurons impairs lipolysis

    OpenAIRE

    Kaushik, Susmita; Arias, Esperanza; Kwon, Hyokjoon; Lopez, Nuria Martinez; Athonvarangkul, Diana; Sahu, Srabani; Schwartz, Gary J.; Pessin, Jeffrey E.; Singh, Rajat

    2012-01-01

    Both selective loss of autophagy in POMC neurons and ageing decrease ?-melanocyte stimulating hormone levels, promoting adiposity, impairing lipolysis and altering glucose homeostasis. These effects can be pharmacologically alleviated, suggesting prevention strategies for obesity and metabolic syndrome.

  18. Mimulone-Induced Autophagy through p53-Mediated AMPK/mTOR Pathway Increases Caspase-Mediated Apoptotic Cell Death in A549 Human Lung Cancer Cells

    OpenAIRE

    An, Hyun-Kyu; Kim, Kyoung-Sook; Lee, Ji-Won; Park, Mi-Hyun; Moon, Hyung-In; Park, Shin-Ji; Baik, Ji-Sue; Kim, Cheorl-Ho; Lee, Young-Choon

    2014-01-01

    Anticancer properties and mechanisms of mimulone (MML), C-geranylflavonoid isolated from the Paulownia tomentosa fruits, were firstly elucidated in this study. MML prevented cell proliferation in a dose- and time-dependent way and triggered apoptosis through the extrinsic pathway in A549 human lung adenocarcinoma cells. Furthermore, MML-treated cells displayed autophagic features, such as the formation of autophagic vacuoles, a primary morphological feature of autophagy, and the accumulation ...

  19. Pharmacology of Acetylcholine-Mediated Cell Signaling in the Lateral Line Organ Following Efferent Stimulation

    OpenAIRE

    Dawkins, Rosie; Keller, Sarah L.; Sewell, William F.

    2004-01-01

    Cholinergic efferent fibers modify hair cell responses to mechanical stimulation. It is hypothesized that calcium entering the hair cell through a nicotinic receptor activates a small-conductance (SK), calcium-activated potassium channel to hyperpolarize the hair cell. The calcium signal may be amplified by calcium-induced calcium release from the synaptic cisternae. Pharmacological tests of these ideas in the intact cochlea have been technically difficult because of the complex and fragile s...

  20. Exaggerated NMDA Mediated LTD in a Mouse Model of Down Syndrome and Pharmacological Rescuing by Memantine

    Science.gov (United States)

    Scott-McKean, Jonah J.; Costa, Alberto C. S.

    2011-01-01

    The Ts65Dn mouse is the best-studied animal model for Down syndrome. In the experiments described here, NMDA-mediated or mGluR-mediated LTD was induced in the CA1 region of hippocampal slices from Ts65Dn and euploid control mice by bath application of 20 [mu]M NMDA for 3 min and 50 [mu]M DHPG for 5 min, respectively. We found that Ts65Dn mice…

  1. Autophagy and the immune function in aging.

    Science.gov (United States)

    Cuervo, Ana Maria; Macian, Fernando

    2014-08-01

    Just when you thought that you had heard it all about autophagy-the conserved cellular process that mediates turnover of cellular constituents in the lysosomes - studies keep coming out highlighting new types of autophagy, new functions for autophagy or even new autophagy-independent roles for the proteins associated with this process. The field of immunology has been riding the autophagic wave since the beginning of its revival; first due to its role in the host defense against pathogens, and more recently through the better understanding of the unique characteristics and functions of different autophagic pathways in immune cells. Here, we describe some of these new functions that are tightening the connection between autophagy and acquired or innate immunity and their malfunctioning with age. PMID:24929664

  2. A novel protoapigenone analog RY10-4 induces breast cancer MCF-7 cell death through autophagy via the Akt/mTOR pathway

    International Nuclear Information System (INIS)

    Protoapigenone is a unique flavonoid and enriched in many ferns, showing potent antitumor activity against a broad spectrum of human cancer cell lines. RY10-4, a modified version of protoapigenone, manifested better anti-proliferation activity in human breast cancer cell line MCF-7. The cytotoxicity of RY10-4 against MCF-7 cells is exhibited in both time- and concentration-dependent manners. Here we investigated a novel effect of RY10-4 mediated autophagy in autophagy defect MCF-7 cells. Employing immunofluorescence assay for microtubule-associated protein light-chain 3 (LC3), monodansylcadaverine staining, Western blotting analyses for LC3 and p62 as well as ultrastructural analysis by transmission electron microscopy, we showed that RY10-4 induced autophagy in MCF-7 cells but protoapigenone did not. Meanwhile, inhibition of autophagy by pharmacological and genetic approaches significantly increased the viability of RY10-4 treated cells, suggesting that the autophagy induced by RY10-4 played as a promotion mechanism for cell death. Further studies revealed that RY10-4 suppressed the activation of mTOR and p70S6K via the Akt/mTOR pathway. Our results provided new insights for the mechanism of RY10-4 induced cell death and the cause of RY10-4 showing better antitumor activity than protoapigenone, and supported further evidences for RY10-4 as a lead to design a promising antitumor agent. - Highlights: • We showed that RY10-4 induced autophagy in MCF-7 cells but protoapigenone did not. • Autophagy induced by RY10-4 played as a promotion mechanism for cell death. • RY10-4 induced autophagy in MCF-7 cell through the Akt/mTOR pathway. • We provided new insights for the mechanism of RY10-4 induced cell death

  3. A novel protoapigenone analog RY10-4 induces breast cancer MCF-7 cell death through autophagy via the Akt/mTOR pathway

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xuenong; Wei, Han; Liu, Ziwei; Yuan, Qianying [Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation of Hubei Province, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China); Wei, Anhua [Department of Pharmacy, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China); Shi, Du; Yang, Xian [Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation of Hubei Province, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China); Ruan, Jinlan, E-mail: jinlan8152@163.com [Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation of Hubei Province, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China)

    2013-07-15

    Protoapigenone is a unique flavonoid and enriched in many ferns, showing potent antitumor activity against a broad spectrum of human cancer cell lines. RY10-4, a modified version of protoapigenone, manifested better anti-proliferation activity in human breast cancer cell line MCF-7. The cytotoxicity of RY10-4 against MCF-7 cells is exhibited in both time- and concentration-dependent manners. Here we investigated a novel effect of RY10-4 mediated autophagy in autophagy defect MCF-7 cells. Employing immunofluorescence assay for microtubule-associated protein light-chain 3 (LC3), monodansylcadaverine staining, Western blotting analyses for LC3 and p62 as well as ultrastructural analysis by transmission electron microscopy, we showed that RY10-4 induced autophagy in MCF-7 cells but protoapigenone did not. Meanwhile, inhibition of autophagy by pharmacological and genetic approaches significantly increased the viability of RY10-4 treated cells, suggesting that the autophagy induced by RY10-4 played as a promotion mechanism for cell death. Further studies revealed that RY10-4 suppressed the activation of mTOR and p70S6K via the Akt/mTOR pathway. Our results provided new insights for the mechanism of RY10-4 induced cell death and the cause of RY10-4 showing better antitumor activity than protoapigenone, and supported further evidences for RY10-4 as a lead to design a promising antitumor agent. - Highlights: • We showed that RY10-4 induced autophagy in MCF-7 cells but protoapigenone did not. • Autophagy induced by RY10-4 played as a promotion mechanism for cell death. • RY10-4 induced autophagy in MCF-7 cell through the Akt/mTOR pathway. • We provided new insights for the mechanism of RY10-4 induced cell death.

  4. Liver autophagy in anorexia nervosa and acute liver injury.

    Science.gov (United States)

    Kheloufi, Marouane; Boulanger, Chantal M; Durand, François; Rautou, Pierre-Emmanuel

    2014-01-01

    Autophagy, a lysosomal catabolic pathway for long-lived proteins and damaged organelles, is crucial for cell homeostasis, and survival under stressful conditions. During starvation, autophagy is induced in numerous organisms ranging from yeast to mammals, and promotes survival by supplying nutrients and energy. In the early neonatal period, when transplacental nutrients supply is interrupted, starvation-induced autophagy is crucial for neonates' survival. In adult animals, autophagy provides amino acids and participates in glucose metabolism following starvation. In patients with anorexia nervosa, autophagy appears initially protective, allowing cells to copes with nutrient deprivation. However, when starvation is critically prolonged and when body mass index reaches 13 kg/m(2) or lower, acute liver insufficiency occurs with features of autophagic cell death, which can be observed by electron microscopy analysis of liver biopsy samples. In acetaminophen overdose, a classic cause of severe liver injury, autophagy is induced as a protective mechanism. Pharmacological enhancement of autophagy protects against acetaminophen-induced necrosis. Autophagy is also activated as a rescue mechanism in response to Efavirenz-induced mitochondrial dysfunction. However, Efavirenz overdose blocks autophagy leading to liver cell death. In conclusion, in acute liver injury, autophagy appears as a protective mechanism that can be however blocked or overwhelmed. PMID:25250330

  5. Liver Autophagy in Anorexia Nervosa and Acute Liver Injury

    Directory of Open Access Journals (Sweden)

    Marouane Kheloufi

    2014-01-01

    Full Text Available Autophagy, a lysosomal catabolic pathway for long-lived proteins and damaged organelles, is crucial for cell homeostasis, and survival under stressful conditions. During starvation, autophagy is induced in numerous organisms ranging from yeast to mammals, and promotes survival by supplying nutrients and energy. In the early neonatal period, when transplacental nutrients supply is interrupted, starvation-induced autophagy is crucial for neonates’ survival. In adult animals, autophagy provides amino acids and participates in glucose metabolism following starvation. In patients with anorexia nervosa, autophagy appears initially protective, allowing cells to copes with nutrient deprivation. However, when starvation is critically prolonged and when body mass index reaches 13 kg/m2 or lower, acute liver insufficiency occurs with features of autophagic cell death, which can be observed by electron microscopy analysis of liver biopsy samples. In acetaminophen overdose, a classic cause of severe liver injury, autophagy is induced as a protective mechanism. Pharmacological enhancement of autophagy protects against acetaminophen-induced necrosis. Autophagy is also activated as a rescue mechanism in response to Efavirenz-induced mitochondrial dysfunction. However, Efavirenz overdose blocks autophagy leading to liver cell death. In conclusion, in acute liver injury, autophagy appears as a protective mechanism that can be however blocked or overwhelmed.

  6. Carbohydrate-mediated polyethylene glycol conjugation of TSH improves its pharmacological properties.

    Science.gov (United States)

    Park, Anna; Honey, Denise M; Hou, Lihui; Bird, Julie J; Zarazinski, Christine; Searles, Michelle; Braithwaite, Christian; Kingsbury, Jonathan S; Kyazike, Josephine; Culm-Merdek, Kerry; Greene, Ben; Stefano, James E; Qiu, Huawei; McPherson, John M; Pan, Clark Q

    2013-03-01

    Thyrogen (thyrotropin alfa for injection), recombinant human TSH (rhTSH), has been successfully used to enhance diagnostic radioiodine scanning and thyroglobulin testing in the follow-up of patients with thyroid cancer and as an adjunctive treatment for radioiodine thyroid remnant ablation. However, the short half-life of rhTSH in the circulation requires a multidose regimen. We developed novel sialic acid-mediated and galactose-mediated conjugation chemistries for targeting polyethylene glycol (PEG) to the three N-linked glycosylation sites on the protein, to prolong plasma half-life by eliminating kidney filtration and potential carbohydrate-mediated clearance. Conjugates of different PEG sizes and copy numbers were screened for reaction yield, TSH receptor binding, and murine phamacokinetics/pharmacodynamics studies. The best performing of these products, a 40-kDa mono-PEGylated sialic acid-mediated conjugate, exhibited a 3.5-fold longer duration of action than rhTSH in rats, as a 5-fold lower affinity was more than compensated by a 23-fold extension of circulation half-life. Biochemical characterization confirmed conjugation through the sialic acids. Correlation of PEG distribution on the three N-linked glycosylation sites and the PEG effect on receptor binding supported the previously reported structure-function relationship of rhTSH glycosylation. This long-acting rhTSH has the potential to significantly improve patient convenience and provider flexibility while reducing potential side effects associated with a sudden elevation of serum TSH. PMID:23389953

  7. Sequential steps of macroautophagy and chaperone-mediated autophagy are involved in the irreversible process of posterior silk gland histolysis during metamorphosis of Bombyx mori.

    Science.gov (United States)

    Shiba, Hajime; Yabu, Takeshi; Sudayama, Makoto; Mano, Nobuhiro; Arai, Naoto; Nakanishi, Teruyuki; Hosono, Kuniaki

    2016-04-15

    To elucidate the degradation process of the posterior silk gland during metamorphosis of the silkworm ITALIC! Bombyx mori, tissues collected on the 6th day after entering the 5th instar (V6), prior to spinning (PS), during spinning (SP) and after cocoon formation (CO) were used to analyze macroautophagy, chaperone-mediated autophagy (CMA) and the adenosine triphosphate (ATP)-dependent ubiquitin proteasome. Immediately after entering metamorphosis stage PS, the levels of ATP and phosphorylated p70S6 kinase protein decreased spontaneously and continued to decline at SP, followed by a notable restoration at CO. In contrast, phosphorylated AMP-activated protein kinase α (AMPKα) showed increases at SP and CO. Most of the Atg8 protein was converted to form II at all stages. The levels of ubiquitinated proteins were high at SP and CO, and low at PS. The proteasome activity was high at V6 and PS but low at SP and CO. In the isolated lysosome fractions, levels of Hsc70/Hsp70 protein began to increase at PS and continued to rise at SP and CO. The lysosomal cathepsin B/L activity showed a dramatic increase at CO. Our results clearly demonstrate that macroautophagy occurs before entering the metamorphosis stage and strongly suggest that the CMA pathway may play an important role in the histolysis of the posterior silk gland during metamorphosis. PMID:26944491

  8. Bozepinib, a novel small antitumor agent, induces PKR-mediated apoptosis and synergizes with IFNα triggering apoptosis, autophagy and senescence

    Science.gov (United States)

    Marchal, Juan Antonio; Carrasco, Esther; Ramirez, Alberto; Jiménez, Gema; Olmedo, Carmen; Peran, Macarena; Agil, Ahmad; Conejo-García, Ana; Cruz-López, Olga; Campos, Joaquin María; García, María Ángel

    2013-01-01

    Bozepinib [(RS)-2,6-dichloro-9-[1-(p-nitrobenzenesulfonyl)-1,2,3,5-tetrahydro-4,1-benzoxazepin-3-yl]-9H-purine] is a potent antitumor compound that is able to induce apoptosis in breast cancer cells. In the present study, we show that bozepinib also has antitumor activity in colon cancer cells, showing 50% inhibitory concentration (IC50) values lower than those described for breast cancer cells and suggesting great potential of this synthetic drug in the treatment of cancer. We identified that the double-stranded RNA-dependent protein kinase (PKR) is a target of bozepinib, being upregulated and activated by the drug. However, p53 was not affected by bozepinib, and was not necessary for induction of apoptosis in either breast or colon cancer cells. In addition, the efficacy of bozepinib was improved when combined with the interferon-alpha (IFNα) cytokine, which enhanced bozepinib-induced apoptosis with involvement of protein kinase PKR. Moreover, we report here, for the first time, that in combined therapy, IFNα induces a clear process of autophagosome formation, and prior treatment with chloroquine, an autophagy inhibitor, is able to significantly reduce IFNα/bozepinib-induced cell death. Finally, we observed that a minor population of caspase 3-deficient MCF-7 cells persisted during long-term treatment with lower doses of bozepinib and the bozepinib/IFNα combination. Curiously, this population showed β-galactosidase activity and a percentage of cells arrested in S phase, that was more evident in cells treated with the bozepinib/IFNα combination than in cells treated with bozepinib or IFNα alone. Considering the resistance of some cancer cells to conventional chemotherapy, combinations enhancing the diversity of the cell death outcome might succeed in delivering more effective and less toxic chemotherapy. PMID:24194639

  9. PI3K/Akt/mTOR activation by suppression of ELK3 mediates chemosensitivity of MDA-MB-231 cells to doxorubicin by inhibiting autophagy.

    Science.gov (United States)

    Park, Ji-Hoon; Kim, Keun Pil; Ko, Jeong-Jae; Park, Kyung-Soon

    2016-08-19

    Drug resistance in breast cancer remains a major obstacle of clinical therapy. We found that suppression of ELK3 in the triple negative breast cancer cell line MDA-MB-231 impaired autophagy and led to a hypersensitive response to doxorubicin treatment. In ELK3-knockdown MDA-MB-231 cells (ELK3 KD), autophagy was not activated under starvation conditions, which is a major stimulus of autophagy activation. We revealed that activation of the PI3K/Akt pathway was the main cause of impaired autophagy in ELK3 KD. Our results suggest that targeting ELK3 may be a potential approach to overcome doxorubicin resistance in breast cancer therapeutics. PMID:27301639

  10. Interleukin 17A inhibits autophagy through activation of PIK3CA to interrupt the GSK3B-mediated degradation of BCL2 in lung epithelial cells

    OpenAIRE

    Liu, Hong; Mi, Su; Li, Zhe; Hua, Fang; Hu, Zhuo-Wei

    2013-01-01

    We recently found that activation of IL17A signaling promotes the development and progression of acute and chronic pulmonary fibrosis, and that the blockade of IL17A activity attenuates pulmonary fibrosis by promoting the resolution of inflammation and the activation of autophagy. Although the induction of autophagy stimulating the collagen degradation in the fibrotic lung tissue has been identified as a mechanism responsible for the antifibrotic role of targeting IL17A, it remains to be clar...

  11. Demonstration of β1-adrenoceptor mediating relaxation of porcine coronary artery by radioligand binding and pharmacological methods

    International Nuclear Information System (INIS)

    β-adrenoceptors in the porcine coronary artery were characterized by a radioligand binding assay using (-)-[3H]dihydroalprenolol (DHA) and also by measuring the relaxant response of isolated coronary artery to norepinephrine. Specific (-)-[3H]DHA binding in the porcine coronary artery was saturable, reversible and of high affinity with a maximal number of binding sites of 63 fmol/mg protein, and it showed a pharmacological specificity as well as stereoselectivity which characterized β-adrenoceptors. The Hofstee analysis of inhibition of (-)-[3H]DHA binding by atenolol, practolol and ICI 118551 has shown that the averaged concentration of β1 and β2-adrenoceptors in this tissue was 68% and 32% respectively. The relaxant response of isolated coronary artery to norepinephrine was competitively antagonized by (-)propranolol, (+)propranolol, atenolol, practolol and ICI 118551. The pA2 values of these adrenoceptor antagonists were significantly correlated with the Ki values for β1 but not β2-adrenoceptors determined by the (-)-[3H]DHA binding assay. Thus, the present study demonstrates that the relaxant response of porcine coronary artery to norepinephrine is predominantly mediated through the stimulation of β1-adrenoceptors on vascular smooth muscles

  12. Inhibition of Autophagy Enhances Curcumin United light irradiation-induced Oxidative Stress and Tumor Growth Suppression in Human Melanoma Cells.

    Science.gov (United States)

    Niu, Tianhui; Tian, Yan; Mei, Zhusong; Guo, Guangjin

    2016-01-01

    Malignant melanoma is the most aggressive form of skin carcinoma, which possesses fast propagating and highly invasive characteristics. Curcumin is a natural phenol compound that has various biological activities, such as anti-proliferative and apoptosis-accelerating impacts on tumor cells. Unfortunately, the therapeutical activities of Cur are severely hindered due to its extremely low bioavailability. In this study, a cooperative therapy of low concentration Cur combined with red united blue light irradiation was performed to inspect the synergistic effects on the apoptosis, proliferation and autophagy in human melanoma A375 cell. The results showed that red united blue light irradiation efficaciously synergized with Cur to trigger oxidative stress-mediated cell death, induce apoptosis and inhibit cell proliferation. Meanwhile, Western blotting revealed that combined disposure induced the formation of autophagosomes. Conversely, inhibition of the autophagy enhanced apoptosis, obstructed cell cycle arrest and induced reversible proliferation arrest to senescence. These findings suggest that Cur combined with red united blue light irradiation could generate photochemo-preventive effects via enhancing apoptosis and triggering autophagy, and pharmacological inhibition of autophagy convert reversible arrested cells to senescence, therefore reducing the possibility that damaged cells might escape programmed death. PMID:27502897

  13. Pharmacological and biochemical characterization of the D-1 dopamine receptor mediating acetylcholine release in rabbit retina

    Energy Technology Data Exchange (ETDEWEB)

    Hensler, J.G.; Cotterell, D.J.; Dubocovich, M.L.

    1987-12-01

    Superfusion with dopamine (0.1 microM-10 mM) evokes calcium-dependent (/sup 3/H)acetylcholine release from rabbit retina labeled in vitro with (/sup 3/H)choline. This effect is antagonized by the D-1 dopamine receptor antagonist SCH 23390. Activation or blockade of D-2 dopamine, alpha-2 or beta receptors did not stimulate or attenuate the release of (/sup 3/H)acetylcholine from rabbit retina. Dopamine receptor agonists evoke the release of (/sup 3/H)acetylcholine with the following order of potency: apomorphine less than or equal to SKF(R)82526 < SKF 85174 < SKF(R)38393 less than or equal to pergolide less than or equal to dopamine (EC50 = 4.5 microM) < SKF(S)82526 less than or equal to SKF(S)38393. Dopamine receptor antagonists inhibited the dopamine-evoked release of (/sup 3/H)acetylcholine: SCH 23390 (IC50 = 1 nM) < (+)-butaclamol less than or equal to cis-flupenthixol < fluphenazine < perphenazine < trans-flupenthixol < R-sulpiride. The potencies of dopamine receptor agonists and antagonists at the dopamine receptor mediating (/sup 3/H)acetylcholine release is characteristic of the D-1 dopamine receptor. These potencies were correlated with the potencies of dopamine receptor agonists and antagonists at the D-1 dopamine receptor in rabbit retina as labeled by (/sup 3/H)SCH 23390, or as determined by adenylate cyclase activity. (/sup 3/H)SCH 23390 binding in rabbit retinal membranes was stable, saturable and reversible. Scatchard analysis of (/sup 3/H)SCH 23390 saturation data revealed a single high affinity binding site (Kd = 0.175 +/- 0.002 nM) with a maximum binding of 482 +/- 12 fmol/mg of protein. The potencies of dopamine receptor agonists to stimulate (/sup 3/H)acetylcholine release were correlated with their potencies to stimulate adenylate cyclase (r = 0.784, P less than .05, n = 7) and with their affinities at (/sup 3/H)SCH 23390 binding sites (r = 0.755, P < .05, n = 8).

  14. Hypoxia, MTOR and autophagy

    OpenAIRE

    Blagosklonny, Mikhail V.

    2013-01-01

    Although hypoxia can cause cell cycle arrest, it may simultaneously suppress a conversion from this arrest to senescence. Furthermore, hypoxia can suppress senescence caused by diverse stimuli, maintaining reversible quiescence instead. Hypoxia activates autophagy and inhibits MTOR, thus also activating autophagy. What is the relationship between autophagy and cellular senescence? Also, can inhibition of MTOR and stimulation of autophagy explain the gerosuppressive effects of hypoxia?

  15. Phosphorylation of the autophagy receptor optineurin restricts Salmonella growth

    DEFF Research Database (Denmark)

    Wild, Philipp; Farhan, Hesso; McEwan, David G; Wagner, Sebastian; Rogov, Vladimir V; Brady, Nathan R; Richter, Benjamin; Korac, Jelena; Waidmann, Oliver; Choudhary, Chunaram; Dötsch, Volker; Bumann, Dirk; Dikic, Ivan

    2011-01-01

    Selective autophagy can be mediated via receptor molecules that link specific cargoes to the autophagosomal membranes decorated by ubiquitin-like microtubule-associated protein light chain 3 (LC3) modifiers. Although several autophagy receptors have been identified, little is known about mechanisms...... controlling their functions in vivo. In this work, we found that phosphorylation of an autophagy receptor, optineurin, promoted selective autophagy of ubiquitin-coated cytosolic Salmonella enterica. The protein kinase TANK binding kinase 1 (TBK1) phosphorylated optineurin on serine-177, enhancing LC3 binding...... affinity and autophagic clearance of cytosolic Salmonella. Conversely, ubiquitin- or LC3-binding optineurin mutants and silencing of optineurin or TBK1 impaired Salmonella autophagy, resulting in increased intracellular bacterial proliferation. We propose that phosphorylation of autophagy receptors might...

  16. Forms, Crosstalks, and the Role of Phospholipid Biosynthesis in Autophagy

    Directory of Open Access Journals (Sweden)

    Leanne Pereira

    2012-01-01

    Full Text Available Autophagy is a highly conserved cellular process occurring during periods of stress to ensure a cell's survival by recycling cytosolic constituents and making products that can be used in energy generation and other essential processes. Three major forms of autophagy exist according to the specific mechanism through which cytoplasmic material is transported to a lysosome. Chaperone-mediated autophagy is a highly selective form of autophagy that delivers specific proteins for lysosomal degradation. Microautophagy is a less selective form of autophagy that occurs through lysosomal membrane invaginations, forming tubes and directly engulfing cytoplasm. Finally, macroautophagy involves formation of new membrane bilayers (autophagosomes that engulf cytosolic material and deliver it to lysosomes. This review provides new insights on the crosstalks between different forms of autophagy and the significance of bilayer-forming phospholipid synthesis in autophagosomal membrane formation.

  17. Induction of C/EBP homologous protein-mediated apoptosis and autophagy by licochalcone A in non-small cell lung cancer cells.

    Science.gov (United States)

    Tang, Zheng-Hai; Chen, Xin; Wang, Zhao-Yu; Chai, Ke; Wang, Ya-Fang; Xu, Xiao-Huang; Wang, Xiao-Wen; Lu, Jia-Hong; Wang, Yi-Tao; Chen, Xiu-Ping; Lu, Jin-Jian

    2016-01-01

    Licochalcone A (LCA), a flavonoid isolated from the famous Chinese medicinal herb Glycyrrhiza uralensis Fisch, presents obvious anti-cancer effects. In this study, the anti-cancer effects and potential mechanisms of LCA in non-small cell lung cancer (NSCLC) cells were studied. LCA decreased cell viability, increased lactate dehydrogenase release, and induced apoptosis in a concentration-dependent manner in NSCLC cells while not in human embryonic lung fibroblast cells. The expression of phosphatidylethanolamine-modified microtubule-associated protein light-chain 3 (LC3-II) and formation of GFP-LC3 punta, two autophagic markers, were increased after treatment with LCA. LCA-induced LC3-II expression was increased when combined with chloroquine (CQ), while knock-down of autophagy related protein (ATG) 7 or ATG5 reversed LCA-induced LC3-II expression and GFP-LC3 punta formation, suggesting that LCA induced autophagy in NSCLC cells. Inhibition of autophagy could not reverse the LCA-induced cell viability decrease and apoptosis. In addition, LCA increased the expression of endoplasmic reticulum stress related proteins, such as binding immunoglobulin protein and C/EBP homologous protein (CHOP). Knock-down of CHOP reversed LCA-induced cell viability decrease, apoptosis, and autophagy. Taken together, LCA-induced autophagic effect is an accompanied phenomenon in NSCLC cells, and CHOP is critical for LCA-induced cell viability decrease, apoptosis, and autophagy. PMID:27184816

  18. Optogenetic evocation of field inhibitory postsynaptic potentials in hippocampal slices: a simple and reliable approach for studying pharmacological effects on GABAA and GABAB receptor-mediated neurotransmission

    OpenAIRE

    Dine, Julien; Kühne, Claudia; Deussing, Jan M.; Eder, Matthias

    2014-01-01

    The GABAergic system is the main source of inhibition in the mammalian brain. Consequently, much effort is still made to develop new modulators of GABAergic synaptic transmission. In contrast to glutamatergic postsynaptic potentials (PSPs), accurate monitoring of GABA receptor-mediated PSPs (GABAR-PSPs) and their pharmacological modulation in brain tissue invariably requires the use of intracellular recording techniques. However, these techniques are expensive, time- and labor-consuming, and,...

  19. Optogenetic Evocation of Field Inhibitory Postsynaptic Potentials in Hippocampal Slices: A Simple and Reliable Approach for Studying Pharmacological Effects on GABAA and GABAB Receptor-Mediated Neurotransmission

    OpenAIRE

    Julien eDine; Claudia eKühne; Deussing, Jan M.; Matthias eEder

    2014-01-01

    The GABAergic system is the main source of inhibition in the mammalian brain. Consequently, much effort is still made to develop new modulators of GABAergic synaptic transmission. In contrast to glutamatergic postsynaptic potentials (PSPs), accurate monitoring of GABA receptor-mediated PSPs (GABAR-PSPs) and their pharmacological modulation in brain tissue invariably requires the use of intracellular recording techniques. However, these techniques are expensive, time- and labor-consuming, and,...

  20. A pivotal role of FOS-mediated BECN1/Beclin 1 upregulation in dopamine D2 and D3 receptor agonist-induced autophagy activation

    Science.gov (United States)

    Wang, Jian-Da; Cao, Yu-Lan; Li, Qian; Yang, Ya-Ping; Jin, Mengmeng; Chen, Dong; Wang, Fen; Wang, Guang-Hui; Qin, Zheng-Hong; Hu, Li-Fang; Liu, Chun-Feng

    2015-01-01

    Autophagy dysfunction is implicated in the pathogenesis of Parkinson disease (PD). BECN1/Beclin 1 acts as a critical regulator of autophagy and other cellular processes; yet, little is known about the function and regulation of BECN1 in PD. In this study, we report that dopamine D2 and D3 receptor (DRD2 and DRD3) activation by pramipexole and quinpirole could enhance BECN1 transcription and promote autophagy activation in several cell lines, including PC12, MES23.5 and differentiated SH-SY5Y cells, and also in tyrosine hydroxylase positive primary midbrain neurons. Moreover, we identified a novel FOS (FBJ murine osteosarcoma viral oncogene homolog) binding sequence (5′-TGCCTCA-3′) in the rat and human Becn1/BECN1 promoter and uncovered an essential role of FOS binding in the enhancement of Becn1 transcription in PC12 cells in response to the dopamine agonist(s). In addition, we demonstrated a critical role of intracellular Ca2+ elevation, followed by the enhanced phosphorylation of CAMK4 (calcium/calmodulin-dependent protein kinase IV) and CREB (cAMP responsive element binding protein) in the increases of FOS expression and autophagy activity. More importantly, pramipexole treatment ameliorated the SNCA/α-synuclein accumulation in rotenone-treated PC12 cells that overexpress wild-type or A53T mutant SNCA by promoting autophagy flux. This effect was also demonstrated in the substantia nigra and the striatum of SNCAA53T transgenic mice. The inhibition of SNCA accumulation by pramipexole was attenuated by cotreatment with the DRD2 and DRD3 antagonists and Becn1 siRNAs. Thus, our findings suggest that DRD2 and DRD3 agonist(s) may induce autophagy activation via a BECN1-dependent pathway and have the potential to reduce SNCA accumulation in PD. PMID:26649942

  1. Autophagy and Autoimmunity CrossTalks

    Directory of Open Access Journals (Sweden)

    Abhisek eBhattacharya

    2013-04-01

    Full Text Available Autophagy, initially viewed as a conserved bulk-degradation mechanism, has emerged as a central player in a multitude of immune functions. Autophagy is important in host defense against intracellular and extracellular pathogens, metabolic syndromes, immune cell homeostasis, antigen processing and presentation and maintenance of tolerance. The observation that the above processes are implicated in triggering or exacerbating autoimmunity raises the possibility that the autophagy pathway is involved in mediating autoimmune processes, either directly or as a consequence of innate or adaptive functions mediated by the pathway. Genome-wide association studies have shown association between single nucleotide polymorphisms (SNPs in autophagy related gene 5 (Atg5, and Atg16l1 with susceptibility to systemic lupus erythematous (SLE and Crohn’s disease, respectively. Enhanced expression of Atg5 was also reported in blood of mice with experimental autoimmune encephalomyelitis (EAE, a mouse model of multiple sclerosis (MS, and in T cells isolated from blood or brain tissues from patients with active relapse of MS. This review explores the roles of autophagy pathway in the innate and adaptive immune systems on regulating or mediating the onset, progression or exacerbation of autoimmune processes.

  2. Autophagy contributes to resistance of tumor cells to ionizing radiation

    International Nuclear Information System (INIS)

    Background and purpose: Autophagy signaling is a novel important target to improve anticancer therapy. To study the role of autophagy on resistance of tumor cells to ionizing radiation (IR), breast cancer cell lines differing in their intrinsic radiosensitivity were used. Materials and methods: Breast cancer cell lines MDA-MB-231 and HBL-100 were examined with respect to clonogenic cell survival and induction of autophagy after radiation exposure and pharmacological interference of the autophagic process. As marker for autophagy the appearance of LC3-I and LC3-II proteins was analyzed by SDS-PAGE and Western blotting. Formation of autophagic vacuoles was monitored by immunofluorescence staining of LC3. Results: LC3-I and LC3-II formation differs markedly in radioresistant MDA-MB-231 versus radiosensitive HBL-100 cells. Western blot analyses of LC3-II/LC3-I ratio indicated marked induction of autophagy by IR in radioresistant MDA-MB-231 cells, but not in radiosensitive HBL-100 cells. Indirect immunofluorescence analysis of LC3-II positive vacuoles confirmed this differential effect. Pre-treatment with 3-methyladenine (3-MA) antagonized IR-induced autophagy. Likewise, pretreatment of radioresistant MDA-231 cells with autophagy inhibitors 3-MA or chloroquine (CQ) significantly reduced clonogenic survival of irradiated cells. Conclusion: Our data clearly indicate that radioresistant breast tumor cells show a strong post-irradiation induction of autophagy, which thus serves as a protective and pro-survival mechanism in radioresistance.

  3. Autophagy in ageing and ageing-associated diseases

    Institute of Scientific and Technical Information of China (English)

    Li-qiang HE; Jia-hong LU; Zhen-yu YUE

    2013-01-01

    Autophagy is a cell self-digestion process via lysosomes that clears "cellular waste",including aberrantly modified proteins or protein aggregates and damaged organelles.Therefore,autophagy is considered a protein and organelle quality control mechanism that maintains normal cellular homeostasis.Dysfunctional autophagy has been observed in ageing tissues and several ageing-associated diseases.Lifespan of model organisms such as yeast,worms,flies,and mice can be extended through promoting autophagy,either by genetic manipulations such as over-expression of Sirtuin 1,or by administrations of rapamycin,resveratrol or spermidine.The evidence supports that autophagy may play an important role in delaying ageing or extending lifespan.In this review,we summarize the current knowledge about autophagy and its regulation,outline recent developments ie the genetic and pharmacological manipulations of autophagy that affects the lifespan,and discuss the role of autophagy in the ageing-related diseases.ow in Center for Neurodegenerative and Neuroimmunologic Diseases,Department of Neurology,University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School,Piscataway,NJ 08854,USA

  4. Autophagy Inhibition Dysregulates TBK1 Signaling and Promotes Pancreatic Inflammation.

    Science.gov (United States)

    Yang, Shenghong; Imamura, Yu; Jenkins, Russell W; Cañadas, Israel; Kitajima, Shunsuke; Aref, Amir; Brannon, Arthur; Oki, Eiji; Castoreno, Adam; Zhu, Zehua; Thai, Tran; Reibel, Jacob; Qian, Zhirong; Ogino, Shuji; Wong, Kwok K; Baba, Hideo; Kimmelman, Alec C; Pasca Di Magliano, Marina; Barbie, David A

    2016-06-01

    Autophagy promotes tumor progression downstream of oncogenic KRAS, yet also restrains inflammation and dysplasia through mechanisms that remain incompletely characterized. Understanding the basis of this paradox has important implications for the optimal targeting of autophagy in cancer. Using a mouse model of cerulein-induced pancreatitis, we found that loss of autophagy by deletion of Atg5 enhanced activation of the IκB kinase (IKK)-related kinase TBK1 in vivo, associated with increased neutrophil and T-cell infiltration and PD-L1 upregulation. Consistent with this observation, pharmacologic or genetic inhibition of autophagy in pancreatic ductal adenocarcinoma cells, including suppression of the autophagy receptors NDP52 or p62, prolonged TBK1 activation and increased expression of CCL5, IL6, and several other T-cell and neutrophil chemotactic cytokines in vitro Defective autophagy also promoted PD-L1 upregulation, which is particularly pronounced downstream of IFNγ signaling and involves JAK pathway activation. Treatment with the TBK1/IKKε/JAK inhibitor CYT387 (also known as momelotinib) not only inhibits autophagy, but also suppresses this feedback inflammation and reduces PD-L1 expression, limiting KRAS-driven pancreatic dysplasia. These findings could contribute to the dual role of autophagy in oncogenesis and have important consequences for its therapeutic targeting. Cancer Immunol Res; 4(6); 520-30. ©2016 AACR. PMID:27068336

  5. Autophagy in Inflammatory Diseases

    Directory of Open Access Journals (Sweden)

    Alexander J. S. Choi

    2011-01-01

    Full Text Available Autophagy provides a mechanism for the turnover of cellular organelles and proteins through a lysosome-dependent degradation pathway. During starvation, autophagy exerts a homeostatic function that promotes cell survival by recycling metabolic precursors. Additionally, autophagy can interact with other vital processes such as programmed cell death, inflammation, and adaptive immune mechanisms, and thereby potentially influence disease pathogenesis. Macrophages deficient in autophagic proteins display enhanced caspase-1-dependent proinflammatory cytokine production and the activation of the inflammasome. Autophagy provides a functional role in infectious diseases and sepsis by promoting intracellular bacterial clearance. Mutations in autophagy-related genes, leading to loss of autophagic function, have been implicated in the pathogenesis of Crohn's disease. Furthermore, autophagy-dependent mechanisms have been proposed in the pathogenesis of several pulmonary diseases that involve inflammation, including cystic fibrosis and pulmonary hypertension. Strategies aimed at modulating autophagy may lead to therapeutic interventions for diseases associated with inflammation.

  6. Transient overexpression of Werner protein rescues starvation induced autophagy in Werner syndrome cells.

    Science.gov (United States)

    Maity, Jyotirindra; Bohr, Vilhelm A; Laskar, Aparna; Karmakar, Parimal

    2014-12-01

    Reduced autophagy may be associated with normal and pathological aging. Here we report a link between autophagy and Werner protein (WRNp), mutated in Werner syndrome, the human premature aging Werner syndrome (WS). WRN mutant fibroblast AG11395 and AG05229 respond weakly to starvation induced autophagy compared to normal cells. While the fusion of phagosomes with lysosome is normal, WS cells contain fewer autophagy vacuoles. Cellular starvation autophagy in WS cells is restored after transfection with full length WRN. Further, siRNA mediated silencing of WRN in the normal fibroblast cell line WI-38 results in decreased autophagy and altered expression of autophagy related proteins. Thus, our observations suggest that WRN may have a role in controlling autophagy and hereby cellular maintenance. PMID:25257404

  7. Adiponectin stimulates autophagy and reduces oxidative stress to enhance insulin sensitivity during high-fat diet feeding in mice.

    Science.gov (United States)

    Liu, Ying; Palanivel, Rengasamy; Rai, Esther; Park, Min; Gabor, Tim V; Scheid, Michael P; Xu, Aimin; Sweeney, Gary

    2015-01-01

    Numerous studies have characterized the antidiabetic effects of adiponectin, yet the precise cellular mechanisms in skeletal muscle, in particular, changes in autophagy, require further clarification. In the current study, we used a high-fat diet (HFD) to induce obesity and insulin resistance in wild-type (WT) or adiponectin knockout (Ad-KO) mice with and without adiponectin replenishment. Temporal analysis of glucose tolerance and insulin sensitivity using hyperinsulinemic-euglycemic clamp and muscle insulin receptor substrate and Akt phosphorylation demonstrated exaggerated and more rapid HFD-induced insulin resistance in skeletal muscle of Ad-KO mice. Superoxide dismutase activity, the reduced glutathione-to-glutathione disulfide ratio, and lipid peroxidation indicated that HFD-induced oxidative stress was corrected by adiponectin. Gene array analysis implicated several antioxidant enzymes, including Gpxs, Prdx, Sod, and Nox4, in mediating this effect. Adiponectin also attenuated palmitate-induced reactive oxygen species production in cultured myotubes and improved insulin-stimulated glucose uptake in primary muscle cells. Increased LC3-II and decreased p62 expression suggested that HFD induced autophagy in muscle of WT mice; however, these changes were not observed in Ad-KO mice. Replenishing adiponectin in Ad-KO mice increased LC3-II and Beclin1 and decreased p62 protein levels, induced fibroblast growth factor-21 expression, and corrected HFD-induced decreases in LC3, Beclin1, and ULK1 gene expression. In vitro studies examining changes in phospho-ULK1 (Ser555), LC3-II, and lysosomal enzyme activity confirmed that adiponectin directly induced autophagic flux in cultured muscle cells in an AMPK-dependent manner. We overexpressed an inactive mutant of Atg5 to create an autophagy-deficient cell model, and together with pharmacological inhibition of autophagy, demonstrated reduced insulin sensitivity under these conditions. In summary, adiponectin stimulated

  8. Cinobufagin induces autophagy-mediated cell death in human osteosarcoma U2OS cells through the ROS/JNK/p38 signaling pathway.

    Science.gov (United States)

    Ma, Kun; Zhang, Chuan; Huang, Man-Yu; Li, Wu-Yin; Hu, Guo-Qiang

    2016-07-01

    The main objective of this study was to explore whether autophagy could be triggered by cinobufagin, and to clarify the role of autophagy in the antitumor effects of cinobufagin on U2OS cells and the underlying mechanisms. U2OS cells were exposed to 15, 30, 60 and 120 mg/l cinobufagin for 0, 12, 24 and 48 h. An MTT assay was used to measure cell viability. FITC-Annexin Ⅴ/PI staining and flow cytometry were used to analyze the apoptotic ratio, while apoptotic morphological changes were assessed by PI and Hoechst 33258 viable cell staining. The effects of autophagy on the cells were investigated with GFP-LC3b green fluorescence plasmid transfection and transmission electron microscopy. The levels of caspase-3, -8, - 9, cleaved PARP, LC3-II/LC3-I, p62 and the activation of JNK/p-38 were detected by western blot analysis. Reactive oxygen species (ROS) fluorescence intensity was examined under fluorescence microscopy with an analysis software system. Cell proliferation was obviously inhibited by cinobufagin in a dose- and time-dependent manner. The apoptosis ratio was gradually increased with treatment time as evidenced by flow cytometric analysis and Hoechst 33258 staining. Exposure to cinobufagin resulted in the activation of caspase-3, -8, -9, as well as cleaved PARP which indicated that cinobufagin induced caspase-dependent apoptosis. Autophagy was confirmed in the cinobufagin-treated cells as evidenced by formation of autophagosomes, accumulation of GFP-LC3 fluorescence particles as well as the upregulation of LC3-II/LC3-I levels. Inhibition of autophagy diminished apoptosis as detected by the MTT assays. Moreover the percentage of apoptotic cells decreased following pretreatment with 3-MA, CQ and si-beclin-1. Cinobufagin also induced phosphorylation of the JNK and p38 signaling pathway as well as ROS generation. The JNK and p38 inhibitors significantly attenuated coexistence of apoptosis and autophagy-related proteins. The ROS scavenger also prevented

  9. Selective Autophagy in Drosophila

    Directory of Open Access Journals (Sweden)

    Ioannis P. Nezis

    2012-01-01

    Full Text Available Autophagy is an evolutionarily conserved process of cellular self-eating and is a major pathway for degradation of cytoplasmic material by the lysosomal machinery. Autophagy functions as a cellular response in nutrient starvation, but it is also associated with the removal of protein aggregates and damaged organelles and therefore plays an important role in the quality control of proteins and organelles. Although it was initially believed that autophagy occurs randomly in the cell, during the last years, there is growing evidence that sequestration and degradation of cytoplasmic material by autophagy can be selective. Given the important role of autophagy and selective autophagy in several disease-related processes such as neurodegeneration, infections, and tumorigenesis, it is important to understand the molecular mechanisms of selective autophagy, especially at the organismal level. Drosophila is an excellent genetically modifiable model organism exhibiting high conservation in the autophagic machinery. However, the regulation and mechanisms of selective autophagy in Drosophila have been largely unexplored. In this paper, I will present an overview of the current knowledge about selective autophagy in Drosophila.

  10. Autophagy in infection.

    Science.gov (United States)

    Deretic, Vojo

    2010-04-01

    Autophagy is a ubiquitous eukaryotic cytoplasmic quality and quantity control pathway. The role of autophagy in cytoplasmic homeostasis seamlessly extends to cell-autonomous defense against intracellular microbes. Recent studies also point to fully integrated, multitiered regulatory and effector connections between autophagy and nearly all facets of innate and adaptive immunity. Autophagy in the immune system as a whole confers measured immune responses; on the flip side, suppression of autophagy can lead to inflammation and tissue damage, as evidenced by Crohn's disease predisposition polymorphisms in autophagy basal apparatus (Atg16L) and regulatory (IRGM) genes. Polymorphisms in the IRGM gene in human populations have also been linked to predisposition to tuberculosis. There are several areas of most recent growth: first, links between autophagy regulators and infectious disease predisposition in human populations; second, demonstration of a role for autophagy in infection control in vivo in animal models; third, the definition of specific antiautophagic defenses in highly evolved pathogens; and fourth, recognition of connections between the ubiquitin system and autophagy of bacteria (and interestingly mitochondria, which are incidentally organelles of bacterial evolutionary origin) via a growing list of modifier and adapter proteins including p62/SQSTM1, NDP52, Atg32, Parkin, and Nix/BNIP3L. PMID:20116986

  11. 运动性细胞自噬是调节骨骼肌代谢稳态的内置机制%Exercise-mediated Autophagy is a Built-in Mechanism to Regulate Skeletal Muscle Metabolic Homeostasis

    Institute of Scientific and Technical Information of China (English)

    钱帅伟; 丁树哲

    2015-01-01

    细胞自噬作为骨骼肌必需的代偿性内置调节机制 ,可在运动、禁食、营养限制和肌肉收缩刺激等能量应激下 ,将胞浆中损伤或衰老的细胞组件(线粒体、内质网、核糖体)、病菌和ROS等代谢废物 ,以及糖原、脂质、非功能或功能性蛋白质等能源物质 ,转运到溶酶体中消化降解 ,从而完善骨骼肌细胞质量控制 ,有效供给细胞更新和代谢平衡所需的能量与合成底物的一种分解代谢装置.运动训练不仅能通过细胞自噬完善骨骼肌线粒体质量控制 ,稳定线粒体功能网络 ,维持骨骼肌代谢稳态 ,还能有效防治胰岛素抵抗、肥胖和 Ⅱ型糖尿病等代谢疾病的发生.运动训练介导的细胞自噬也可使骨骼肌质量及其功能根据运动项目的自身特点进行积极调整和适应 ,从而进一步维持骨骼肌代谢功能稳态.%As a compensatory and built-in mechanism of skeletal muscle ,autophagy not only could degrade reactive oxygen species ,bacteria ,aging or damaged organelles such as mitochon-dria ,endoplasmic reticulum ,ribosome ,as well as degrade glycogen ,lipid ,non-functional and functional protein when suffer energy stress such as exercise ,fasting ,nutrition restriction and muscle contraction .Autophagy accordingly could improve muscle quality control ,as well as en-ergy and synthetic substrates for cellular renewal and metabolism .Exercise training-mediated autophagy not only could improve mitochondrial quality control ,stabilize mitochondrial function network ,as well as maintain metabolic homeostasis of muscle ,but also effectively prevent insu-lin resistance ,obesity ,type Ⅱ diabetes and some other metabolic diseases .Exercise training-me-diated autophagy could also entirely adapt muscle mass and function to their items ,and further improve muscle metabolism and functional homeostasis .

  12. Canonical autophagy does not contribute to cellular radioresistance

    International Nuclear Information System (INIS)

    Background: (Pre)clinical studies indicate that autophagy inhibition increases response to anti-cancer therapies. Although promising, due to contradicting reports, it remains unclear if radiation therapy changes autophagy activity and if autophagy inhibition changes the cellular intrinsic radiosensitivity. Discrepancies may result from different assays and models through off-target effects and influencing other signaling routes. In this study, we directly compared the effects of genetic and pharmacological inhibition of autophagy after irradiation in human cancer cell lines. Materials and methods: Changes in autophagy activity after ionizing radiation (IR) were assessed by flux analysis in eight cell lines. Clonogenic survival, DNA damage (COMET-assay) and H2AX phosphorylation were assessed after chloroquine or 3-methyladenine pretreatment and after ATG7 or LC3b knockdown. Results: IR failed to induce autophagy and chloroquine failed to change intrinsic radiosensitivity of cells. Interestingly, 3-methyladenine and ATG7- or LC3b-deficiency sensitized cancer cells to irradiation. Surprisingly, the radiosensitizing effect of 3-methyladenine was also observed in ATG7 and LC3b deficient cells and was associated with attenuated γ-H2AX formation and DNA damage repair. Conclusion: Our data demonstrate that the anti-tumor effects of chloroquine are independent of changes in intrinsic radioresistance. Furthermore, ATG7 and LC3b support radioresistance independent of canonical autophagy that involves lysosomal degradation

  13. NF-κB p65 repression by the sesquiterpene lactone, Helenalin, contributes to the induction of autophagy cell death

    OpenAIRE

    Lim Chuan; Fu Pan; Ky Nung; Zhu Hong; Feng XiaoLing; Li Jinming; Srinivasan Kandhadayar; Hamza Mohamed; Zhao Yan

    2012-01-01

    Abstract Background Numerous studies have demonstrated that autophagy plays a vital role in maintaining cellular homeostasis. Interestingly, several anticancer agents were found to exert their anticancer effects by triggering autophagy. Emerging data suggest that autophagy represents a novel mechanism that can be exploited for therapeutic benefit. Pharmacologically active natural compounds such as those from marine, terrestrial plants and animals represent a promising resource for novel antic...

  14. NF-κB p65 repression by the sesquiterpene lactone, Helenalin, contributes to the induction of autophagy cell death

    Directory of Open Access Journals (Sweden)

    Lim Chuan

    2012-07-01

    Full Text Available Abstract Background Numerous studies have demonstrated that autophagy plays a vital role in maintaining cellular homeostasis. Interestingly, several anticancer agents were found to exert their anticancer effects by triggering autophagy. Emerging data suggest that autophagy represents a novel mechanism that can be exploited for therapeutic benefit. Pharmacologically active natural compounds such as those from marine, terrestrial plants and animals represent a promising resource for novel anticancer drugs. There are several prominent examples from the past proving the success of natural products and derivatives exhibiting anticancer activity. Helenalin, a sesquiterpene lactone has been demonstrated to have potent anti-inflammatory and antitumor activity. Albeit previous studies demonstrating helenalin’s multi modal action on cellular proliferative and apoptosis, the mechanisms underlying its action are largely unexplained. Methods To deduce the mechanistic action of helenalin, cancer cells were treated with the drug at various concentrations and time intervals. Using western blot, FACS analysis, overexpression and knockdown studies, cellular signaling pathways were interrogated focusing on apoptosis and autophagy markers. Results We show here that helenalin induces sub-G1 arrest, apoptosis, caspase cleavage and increases the levels of the autophagic markers. Suppression of caspase cleavage by the pan caspase inhibitor, Z-VAD-fmk, suppressed induction of LC3-B and Atg12 and reduced autophagic cell death, indicating caspase activity was essential for autophagic cell death induced by helenalin. Additionally, helenalin suppressed NF-κB p65 expression in a dose and time dependent manner. Exogenous overexpression of p65 was accompanied by reduced levels of cell death whereas siRNA mediated suppression led to augmented levels of caspase cleavage, autophagic cell death markers and increased cell death. Conclusions Taken together, these results show

  15. Chemical Inhibition of Autophagy

    DEFF Research Database (Denmark)

    Baek, Eric; Lin Kim, Che; Gyeom Kim, Mi;

    2016-01-01

    Chinese hamster ovary (CHO) cells activate and undergo apoptosis and autophagy for various environmental stresses. Unlike apoptosis, studies on increasing the production of therapeutic proteins in CHO cells by targeting the autophagy pathway are limited. In order to identify the effects of chemic...

  16. Autophagy and cancer

    Institute of Scientific and Technical Information of China (English)

    Si-Zhao; Lu; Duygu; Dee; Harrison-Findik

    2013-01-01

    Autophagy is a homeostatic and evolutionarily conserved mechanism of self-digestion by which the cells degrade and recycle long-lived proteins and excess or damaged organelles.Autophagy is activated in response to both physiological and pathological stimuli including growth factor depletion,energy deficiency or the upregulation of Bcl-2 protein expression.A novel role of autophagy in various cancers has been proposed.Interestingly,evidence that supports both a positive and negative role of autophagy in the pathogenesis of cancer has been reported.As a tumor suppression mechanism,autophagy maintains genome stability,induces senescence and possibly autophagic cell death.On the other hand,autophagy participates in tumor growth and maintenance by supplying metabolic substrate,limiting oxidative stress,and maintaining cancer stem cell population.It has been proposed that the differential roles of autophagy in cancer are disease type and stage specific.In addition,substrate selectivity might be involved in carrying out the specific effect of autophagy in cancer,and represents one of the potential directions for future studies.

  17. Autophagy: A double-edged sword in Alzheimer's disease

    Indian Academy of Sciences (India)

    Ying-Tsen Tung; Bo-Jeng Wang; Ming-Kuan Hu; Wen-Ming Hsu; Hsinyu Lee; Wei-Pang Huang; Yung-Feng Liao

    2012-03-01

    Autophagy is a major protein degradation pathway that is essential for stress-induced and constitutive protein turnover. Accumulated evidence has demonstrated that amyloid- (A) protein can be generated in autophagic vacuoles, promoting its extracellular deposition in neuritic plaques as the pathological hallmark of Alzheimer’s disease (AD). The molecular machinery for A generation, including APP, APP-C99 and -/-secretases, are all enriched in autophagic vacuoles. The induction of autophagy can be vividly observed in the brain at early stages of sporadic AD and in an AD transgenic mouse model. Accumulated evidence has also demonstrated a neuroprotective role of autophagy in mediating the degradation of aggregated proteins that are causative of various neurodegenerative diseases. Autophagy is thus widely regarded as an intracellular hub for the removal of the detrimental A peptides and Tau aggregates. Nonetheless, compelling data also reveal an unfavorable function of autophagy in facilitating the production of intracellular A. The two faces of autophagy on the homeostasis of A place it in a very unique and intriguing position in ADpathogenesis. This article briefly summarizes seminal discoveries that are shedding new light on the critical and unique roles of autophagy in AD and potential therapeutic approaches against autophagy-elicited AD.

  18. Cellular and Molecular Connections between Autophagy and Inflammation

    Directory of Open Access Journals (Sweden)

    Pierre Lapaquette

    2015-01-01

    Full Text Available Autophagy is an intracellular catabolic pathway essential for the recycling of proteins and larger substrates such as aggregates, apoptotic corpses, or long-lived and superfluous organelles whose accumulation could be toxic for cells. Because of its unique feature to engulf part of cytoplasm in double-membrane cup-shaped structures, which further fuses with lysosomes, autophagy is also involved in the elimination of host cell invaders and takes an active part of the innate and adaptive immune response. Its pivotal role in maintenance of the inflammatory balance makes dysfunctions of the autophagy process having important pathological consequences. Indeed, defects in autophagy are associated with a wide range of human diseases including metabolic disorders (diabetes and obesity, inflammatory bowel disease (IBD, and cancer. In this review, we will focus on interrelations that exist between inflammation and autophagy. We will discuss in particular how mediators of inflammation can regulate autophagy activity and, conversely, how autophagy shapes the inflammatory response. Impact of genetic polymorphisms in autophagy-related gene on inflammatory bowel disease will be also discussed.

  19. Autophagy and Liver Ischemia-Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Raffaele Cursio

    2015-01-01

    Full Text Available Liver ischemia-reperfusion (I-R injury occurs during liver resection, liver transplantation, and hemorrhagic shock. The main mode of liver cell death after warm and/or cold liver I-R is necrosis, but other modes of cell death, as apoptosis and autophagy, are also involved. Autophagy is an intracellular self-digesting pathway responsible for removal of long-lived proteins, damaged organelles, and malformed proteins during biosynthesis by lysosomes. Autophagy is found in normal and diseased liver. Although depending on the type of ischemia, warm and/or cold, the dynamic process of liver I-R results mainly in adenosine triphosphate depletion and in production of reactive oxygen species (ROS, leads to both, a local ischemic insult and an acute inflammatory-mediated reperfusion injury, and results finally in cell death. This process can induce liver dysfunction and can increase patient morbidity and mortality after liver surgery and hemorrhagic shock. Whether autophagy protects from or promotes liver injury following warm and/or cold I-R remains to be elucidated. The present review aims to summarize the current knowledge in liver I-R injury focusing on both the beneficial and the detrimental effects of liver autophagy following warm and/or cold liver I-R.

  20. LC3B is indispensable for selective autophagy of p62 but not basal autophagy

    International Nuclear Information System (INIS)

    Highlights: • Knockdown of LC3 or GABARAP families did not affect the basal autophagy. • LC3B has a higher affinity for the autophagy-specific substrate, p62, than GABARAPs. • siRNA-mediated knockdown of LC3B, but not that of GABARAPs, resulted in significant accumulation of p62. - Abstract: Autophagy is a unique intracellular protein degradation system accompanied by autophagosome formation. Besides its important role through bulk degradation in supplying nutrients, this system has an ability to degrade certain proteins, organelles, and invading bacteria selectively to maintain cellular homeostasis. In yeasts, Atg8p plays key roles in both autophagosome formation and selective autophagy based on its membrane fusion property and interaction with autophagy adaptors/specific substrates. In contrast to the single Atg8p in yeast, mammals have 6 homologs of Atg8p comprising LC3 and GABARAP families. However, it is not clear these two families have different or similar functions. The aim of this study was to determine the separate roles of LC3 and GABARAP families in basal/constitutive and/or selective autophagy. While the combined knockdown of LC3 and GABARAP families caused a defect in long-lived protein degradation through lysosomes, knockdown of each had no effect on the degradation. Meanwhile, knockdown of LC3B but not GABARAPs resulted in significant accumulation of p62/Sqstm1, one of the selective substrate for autophagy. Our results suggest that while mammalian Atg8 homologs are functionally redundant with regard to autophagosome formation, selective autophagy is regulated by specific Atg8 homologs

  1. LC3B is indispensable for selective autophagy of p62 but not basal autophagy

    Energy Technology Data Exchange (ETDEWEB)

    Maruyama, Yoko [Protein Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506 (Japan); Department of Pediatrics, School of Medicine, Keio University, Tokyo 160-8582 (Japan); Sou, Yu-Shin; Kageyama, Shun [Protein Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506 (Japan); Takahashi, Takao [Department of Pediatrics, School of Medicine, Keio University, Tokyo 160-8582 (Japan); Ueno, Takashi [Division of Proteomics and Biomolecular Science, Center for Biomedical Research Resources, Juntendo University Graduate School of Medicine, Tokyo 113-8421 (Japan); Tanaka, Keiji [Laboratory of Protein Metabolism, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506 (Japan); Komatsu, Masaaki, E-mail: komatsu-ms@igakuken.or.jp [Protein Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506 (Japan); Department of Biochemistry, School of Medicine, Niigata University, Niigata 951-8510 (Japan); Ichimura, Yoshinobu, E-mail: ichimura-ys@igakuken.or.jp [Protein Metabolism Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506 (Japan)

    2014-03-28

    Highlights: • Knockdown of LC3 or GABARAP families did not affect the basal autophagy. • LC3B has a higher affinity for the autophagy-specific substrate, p62, than GABARAPs. • siRNA-mediated knockdown of LC3B, but not that of GABARAPs, resulted in significant accumulation of p62. - Abstract: Autophagy is a unique intracellular protein degradation system accompanied by autophagosome formation. Besides its important role through bulk degradation in supplying nutrients, this system has an ability to degrade certain proteins, organelles, and invading bacteria selectively to maintain cellular homeostasis. In yeasts, Atg8p plays key roles in both autophagosome formation and selective autophagy based on its membrane fusion property and interaction with autophagy adaptors/specific substrates. In contrast to the single Atg8p in yeast, mammals have 6 homologs of Atg8p comprising LC3 and GABARAP families. However, it is not clear these two families have different or similar functions. The aim of this study was to determine the separate roles of LC3 and GABARAP families in basal/constitutive and/or selective autophagy. While the combined knockdown of LC3 and GABARAP families caused a defect in long-lived protein degradation through lysosomes, knockdown of each had no effect on the degradation. Meanwhile, knockdown of LC3B but not GABARAPs resulted in significant accumulation of p62/Sqstm1, one of the selective substrate for autophagy. Our results suggest that while mammalian Atg8 homologs are functionally redundant with regard to autophagosome formation, selective autophagy is regulated by specific Atg8 homologs.

  2. The BMI1 polycomb protein represses cyclin G2-induced autophagy to support proliferation in chronic myeloid leukemia cells.

    Science.gov (United States)

    Mourgues, L; Imbert, V; Nebout, M; Colosetti, P; Neffati, Z; Lagadec, P; Verhoeyen, E; Peng, C; Duprez, E; Legros, L; Rochet, N; Maguer-Satta, V; Nicolini, F-E; Mary, D; Peyron, J-F

    2015-10-01

    The BMI1 polycomb protein regulates self-renewal, proliferation and survival of cancer-initiating cells essentially through epigenetic repression of the CDKN2A tumor suppressor locus. We demonstrate here for the first time that BMI1 also prevents autophagy in chronic myeloid leukemia (CML) cell lines, to support their proliferation and clonogenic activity. Using chromatin immunoprecipitation, we identified CCNG2/cyclin G2 (CCNG2) as a direct BMI1 target. BMI1 downregulation in CD34+ CML cells by PTC-209 pharmacological treatment or shBMI1 transduction triggered CCNG2 expression and decreased clonogenic activity. Also, ectopic expression of CCNG2 in CD34+ CML cells strongly decreased their clonogenicity. CCNG2 was shown to act by disrupting the phosphatase 2A complex, which activates a PKCζ-AMPK-JNK-ERK pathway that engages autophagy. We observed that BMI1 and CCNG2 levels evolved inversely during the progression of CML towards an acute deadly phase, and therefore hypothesized that BMI1 could support acute transformation of CML through the silencing of a CCNG2-mediated tumor-suppressive autophagy response. PMID:25925206

  3. Targeting Autophagy Addiction in Cancer

    OpenAIRE

    Mancias, Joseph Douglas; Kimmelman, Alec C

    2011-01-01

    Autophagy inhibition is a novel cancer therapeutic strategy in the early stages of clinical trial testing. The initial rationale for using autophagy inhibition was generated by research revealing that autophagy is upregulated in response to external stresses, including chemotherapy and radiotherapy. Combining autophagy inhibition with agents that induce autophagy as a pro-survival response may therefore increase their therapeutic efficacy. Recent research has shown that some cancer cells, ...

  4. IFNB1/interferon-ß-induced autophagy in MCF-7 breast cancer cells counteracts its proapoptotic function

    DEFF Research Database (Denmark)

    Ambjørn, Malene; Ejlerskov, Patrick; Liu, Yawei; Lees, Michael; Jäättelä, Marja; Navikas, Shohreh

    2013-01-01

    survival pathways leading to treatment resistance. Defects in autophagy, a conserved cellular degradation pathway, are implicated in numerous cancer diseases. Autophagy is induced in response to cancer therapies and can contribute to treatment resistance. While the type II IFN, IFNG, which in many aspects...... differs significantly from type I IFNs, can induce autophagy, no such function for any type I IFN has been reported. We show here that IFNB1 induces autophagy in MCF-7, MDAMB231 and SKBR3 breast cancer cells by measuring the turnover of two autophagic markers, MAP1LC3B/LC3 and SQSTM1/p62. The induction of...... autophagy in MCF-7 cells occurred upstream of the negative regulator of autophagy MTORC1, and autophagosome formation was dependent on the known core autophagy molecule ATG7 and the IFNB1 signaling molecule STAT1. Using siRNA-mediated silencing of several core autophagy molecules and STAT1, we provide...

  5. Autophagy in protists.

    Science.gov (United States)

    Duszenko, Michael; Ginger, Michael L; Brennand, Ana; Gualdrón-López, Melisa; Colombo, María Isabel; Coombs, Graham H; Coppens, Isabelle; Jayabalasingham, Bamini; Langsley, Gordon; de Castro, Solange Lisboa; Menna-Barreto, Rubem; Mottram, Jeremy C; Navarro, Miguel; Rigden, Daniel J; Romano, Patricia S; Stoka, Veronika; Turk, Boris; Michels, Paul A M

    2011-02-01

    Autophagy is the degradative process by which eukaryotic cells digest their own components using acid hydrolases within the lysosome. Originally thought to function almost exclusively in providing starving cells with nutrients taken from their own cellular constituents, autophagy is in fact involved in numerous cellular events including differentiation, turnover of macromolecules and organelles, and defense against parasitic invaders. During the last 10-20 years, molecular components of the autophagic machinery have been discovered, revealing a complex interactome of proteins and lipids, which, in a concerted way, induce membrane formation to engulf cellular material and target it for lysosomal degradation. Here, our emphasis is autophagy in protists. We discuss experimental and genomic data indicating that the canonical autophagy machinery characterized in animals and fungi appeared prior to the radiation of major eukaryotic lineages. Moreover, we describe how comparative bioinformatics revealed that this canonical machinery has been subject to moderation, outright loss or elaboration on multiple occasions in protist lineages, most probably as a consequence of diverse lifestyle adaptations. We also review experimental studies illustrating how several pathogenic protists either utilize autophagy mechanisms or manipulate host-cell autophagy in order to establish or maintain infection within a host. The essentiality of autophagy for the pathogenicity of many parasites, and the unique features of some of the autophagy-related proteins involved, suggest possible new targets for drug discovery. Further studies of the molecular details of autophagy in protists will undoubtedly enhance our understanding of the diversity and complexity of this cellular phenomenon and the opportunities it offers as a drug target. PMID:20962583

  6. Autophagy Induction Protects Against 7-Oxysterol-induced Cell Death via Lysosomal Pathway and Oxidative Stress

    OpenAIRE

    Xi-Ming Yuan; Nargis Sultana; Nabeel Siraj; Ward, Liam J.; Bijar Ghafouri; Wei Li

    2016-01-01

    7-Oxysterols are major toxic components in oxidized low-density lipoprotein and human atheroma lesions, which cause lysosomal membrane permeabilization (LMP) and cell death. Autophagy may function as a survival mechanism in this process. Here, we investigated whether 7-oxysterols mixed in an atheroma-relevant proportion induce autophagy, whether autophagy induction influences 7-oxysterol-mediated cell death, and the underlying mechanisms, by focusing on cellular lipid levels, oxidative stress...

  7. Optogenetic Evocation of Field Inhibitory Postsynaptic Potentials in Hippocampal Slices: A Simple and Reliable Approach for Studying Pharmacological Effects on GABAA and GABAB Receptor-Mediated Neurotransmission

    Directory of Open Access Journals (Sweden)

    Julien eDine

    2014-01-01

    Full Text Available The GABAergic system is the main source of inhibition in the mammalian brain. Consequently, much effort is still made to develop new modulators of GABAergic synaptic transmission. In contrast to glutamatergic postsynaptic potentials (PSPs, accurate monitoring of GABA receptor-mediated PSPs (GABAR-PSPs and their pharmacological modulation in brain tissue invariably requires the use of intracellular recording techniques. However, these techniques are expensive, time- and labor-consuming, and, in case of the frequently employed whole-cell patch-clamp configuration, impact on intracellular ion concentrations, signaling cascades, and pH buffering systems. Here, we describe a novel approach to circumvent these drawbacks. In particular, we demonstrate in mouse hippocampal slices that selective optogenetic activation of interneurons leads to prominent field inhibitory GABAAR- and GABABR-PSPs in area CA1 which are easily and reliably detectable by a single extracellular recording electrode. The field PSPs exhibit typical temporal and pharmacological characteristics, display pronounced paired-pulse depression, and remain stable over many consecutive evocations. Additionally validating the methodological value of this approach, we further show that the neuroactive steroid 5-THDOC (5 µM shifts the inhibitory GABAAR-PSPs towards excitatory ones.

  8. Lithium and autophagy.

    Science.gov (United States)

    Motoi, Yumiko; Shimada, Kohei; Ishiguro, Koichi; Hattori, Nobutaka

    2014-06-18

    Lithium, a drug used to treat bipolar disorders, has a variety of neuroprotective mechanisms, including autophagy regulation, in various neuropsychiatric conditions. In neurodegenerative diseases, lithium enhances degradation of aggregate-prone proteins, including mutated huntingtin, phosphorylated tau, and α-synuclein, and causes damaged mitochondria to degrade, while in a mouse model of cerebral ischemia and Alzheimer's disease autophagy downregulation by lithium is observed. The signaling pathway of lithium as an autophagy enhancer might be associated with the mammalian target of rapamycin (mTOR)-independent pathway, which is involved in myo-inositol-1,4,5-trisphosphate (IP3) in Huntington's disease and Parkinson's disease. However, the mTOR-dependent pathway might be involved in inhibiting glycogen synthase kinase-3β (GSK3β) in other diseases. Lithium's autophagy-enhancing property may contribute to the therapeutic benefit of patients with neuropsychiatric disorders. PMID:24738557

  9. VMP1 related autophagy and apoptosis in colorectal cancer cells: VMP1 regulates cell death

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Qinyi [Department of Ultrasonograph, Changshu No. 2 People’s Hospital, Changshu (China); Zhou, Hao; Chen, Yan [Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou (China); Shen, Chenglong [Department of General Surgery, Changshu No. 2 People’s Hospital, Changshu (China); He, Songbing; Zhao, Hua; Wang, Liang [Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou (China); Wan, Daiwei, E-mail: 372710369@qq.com [Department of Hepatobiliary Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou (China); Gu, Wen, E-mail: 505339704@qq.com [Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou (China)

    2014-01-17

    Highlights: •This research confirmed VMP1 as a regulator of autophagy in colorectal cancer cell lines. •We proved the pro-survival role of VMP1-mediated autophagy in colorectal cancer cell lines. •We found the interaction between VMP1 and BECLIN1 also existing in colorectal cancer cell lines. -- Abstract: Vacuole membrane protein 1 (VMP1) is an autophagy-related protein and identified as a key regulator of autophagy in recent years. In pancreatic cell lines, VMP1-dependent autophagy has been linked to positive regulation of apoptosis. However, there are no published reports on the role of VMP1 in autophagy and apoptosis in colorectal cancers. Therefore, to address this gap of knowledge, we decided to interrogate regulation of autophagy and apoptosis by VMP1. We have studied the induction of autophagy by starvation and rapamycin treatment in colorectal cell lines using electron microscopy, immunofluorescence, and immunoblotting. We found that starvation-induced autophagy correlated with an increase in VMP1 expression, that VMP1 interacted with BECLIN1, and that siRNA mediated down-regulation of VMP1-reduced autophagy. Next, we examined the relationship between VMP1-dependent autophagy and apoptosis and found that VMP1 down-regulation sensitizes cells to apoptosis and that agents that induce apoptosis down-regulate VMP1. In conclusion, similar to its reported role in other cell types, VMP1 is an important regulator of autophagy in colorectal cell lines. However, in contrast to its role in pancreatic cell lines, in colorectal cancer cells, VMP1-dependent autophagy appears to be pro-survival rather than pro-cell death.

  10. VMP1 related autophagy and apoptosis in colorectal cancer cells: VMP1 regulates cell death

    International Nuclear Information System (INIS)

    Highlights: •This research confirmed VMP1 as a regulator of autophagy in colorectal cancer cell lines. •We proved the pro-survival role of VMP1-mediated autophagy in colorectal cancer cell lines. •We found the interaction between VMP1 and BECLIN1 also existing in colorectal cancer cell lines. -- Abstract: Vacuole membrane protein 1 (VMP1) is an autophagy-related protein and identified as a key regulator of autophagy in recent years. In pancreatic cell lines, VMP1-dependent autophagy has been linked to positive regulation of apoptosis. However, there are no published reports on the role of VMP1 in autophagy and apoptosis in colorectal cancers. Therefore, to address this gap of knowledge, we decided to interrogate regulation of autophagy and apoptosis by VMP1. We have studied the induction of autophagy by starvation and rapamycin treatment in colorectal cell lines using electron microscopy, immunofluorescence, and immunoblotting. We found that starvation-induced autophagy correlated with an increase in VMP1 expression, that VMP1 interacted with BECLIN1, and that siRNA mediated down-regulation of VMP1-reduced autophagy. Next, we examined the relationship between VMP1-dependent autophagy and apoptosis and found that VMP1 down-regulation sensitizes cells to apoptosis and that agents that induce apoptosis down-regulate VMP1. In conclusion, similar to its reported role in other cell types, VMP1 is an important regulator of autophagy in colorectal cell lines. However, in contrast to its role in pancreatic cell lines, in colorectal cancer cells, VMP1-dependent autophagy appears to be pro-survival rather than pro-cell death

  11. Pharmacological evidence that alpha2A- and alpha2C-adrenoceptors mediate the inhibition of cardioaccelerator sympathetic outflow in pithed rats.

    Science.gov (United States)

    Cobos-Puc, Luis E; Villalón, Carlos M; Sánchez-López, Araceli; Lozano-Cuenca, Jair; Pertz, Heinz H; Görnemann, Tilo; Centurión, David

    2007-01-12

    It has been suggested that the alpha(2)-adrenoceptors mediating cardiac sympatho-inhibition in pithed rats closely resemble the pharmacological profile of the alpha(2A)-adrenoceptor subtype. However, several lines of evidence suggest that more than one subtype may be involved. Thus, the present study has pharmacologically re-evaluated the receptor subtype(s) involved in the inhibitory effect of the alpha(2)-adrenoceptor agonist, B-HT 933, on the tachycardic responses elicited by selective cardiac sympathetic stimulation (0.03, 0.1, 0.3, 1 and 3 Hz) in desipramine-pretreated pithed rats. I.v. continuous infusions of B-HT 933 (30 microg/kg min), which failed to modify the tachycardic responses to exogenous noradrenaline, inhibited those induced by preganglionic (C(7)-T(1)) stimulation of the cardiac sympathetic outflow at all frequencies of stimulation (0.03-3 Hz). This cardiac sympatho-inhibitory response to B-HT 933 was: (1) unaltered by saline (1 ml/kg) or the antagonists BRL44408 (100 microg/kg; alpha(2A)) or imiloxan (3000 and 10,000 microg/kg; alpha(2B)); (2) partially antagonized by BRL44408 (300 microg/kg) or MK912 (10 microg/kg; alpha(2C)) given separately; and (3) completely antagonized by rauwolscine (300 microg/kg; alpha(2)), MK912 (30 microg/kg) or the combination of BRL44408 (300 microg/kg) plus MK912 (10 microg/kg). Moreover, the above doses of antagonists, which are high enough to block their respective receptors, failed to block per se the tachycardic responses to sympathetic stimulation. These results suggest that the cardiac sympatho-inhibition induced by B-HT 933 in pithed rats is mainly mediated by stimulation of alpha(2A)- and alpha(2C)-adrenoceptors. PMID:17109851

  12. Receptor-independent, vacuolar ATPase-mediated cellular uptake of histamine receptor-1 ligands: Possible origin of pharmacological distortions and side effects

    International Nuclear Information System (INIS)

    The aims of this study were to investigate whether several histamine receptor agonists and antagonists are subjected to receptor-independent ion trapping into acidic organelles, and whether this sequestration influences their pharmacological or toxicological properties. Vacuolar (V)-ATPase-dependent intracellular sequestration of agonists was recognized as morphological alterations (large fluid-filled vacuoles for betahistine and 1-methylhistamine, granular uptake for fluorescent BODIPY FL histamine) prevented by the specific V-ATPase inhibitor bafilomycin A1 in rabbit vascular smooth muscle cells. Lipophilicity was the major determinant of these cellular effects (order of potency: BODIPY FL histamine > betahistine > 1-methylhistamine > histamine) that occurred at high concentrations. This ranking was dissociable from the potency order for H1 receptor-mediated contraction of the rabbit aorta, a response uninfluenced by bafilomycin. Antihistamines are inherently more lipophilic and caused vacuolization of a proportion of cells at 5-500 μM. Agonist or antagonist-induced vacuoles were of macroautophagic nature (labeled with GFP-conjugated LC3, Rab7 and CD63; detection of LC3 II). Further, the 2 most lipophilic antihistamines tested, astemizole and terfenadine, were potentiated by V-ATPase blockade in the aortic contractility assay (13- and 3.6-fold more potent, respectively, pA2 scale), suggesting that V-ATPase-mediated cation trapping sequesters these antagonists from the vicinity of H1 receptors in the therapeutic concentration range. This potentiation did not apply to less lipophilic antagonists (pyrilamine, diphenhydramine). While some agonists and all tested antagonists of the histamine H1 receptors induce the V-ATPase-dependent vacuolar and autophagic cytopathology, sequestration affects the pharmacology of only the most lipophilic antagonists, the ones prone to off-target arrhythmogenic side effects

  13. Piperlongumine induces autophagy by targeting p38 signaling.

    Science.gov (United States)

    Wang, Y; Wang, J-W; Xiao, X; Shan, Y; Xue, B; Jiang, G; He, Q; Chen, J; Xu, H-G; Zhao, R-X; Werle, K D; Cui, R; Liang, J; Li, Y-L; Xu, Z-X

    2013-01-01

    Piperlongumine (PL), a natural product isolated from the plant species Piper longum L., can selectively induce apoptotic cell death in cancer cells by targeting the stress response to reactive oxygen species (ROS). Here we show that PL induces cell death in the presence of benzyloxycarbonylvalyl-alanyl-aspartic acid (O-methyl)-fluoro-methylketone (zVAD-fmk), a pan-apoptotic inhibitor, and in the presence of necrostatin-1, a necrotic inhibitor. Instead PL-induced cell death can be suppressed by 3-methyladenine, an autophagy inhibitor, and substantially attenuated in cells lacking the autophagy-related 5 (Atg5) gene. We further show that PL enhances autophagy activity without blocking autophagy flux. Application of N-acetyl-cysteine, an antioxidant, markedly reduces PL-induced autophagy and cell death, suggesting an essential role for intracellular ROS in PL-induced autophagy. Furthermore, PL stimulates the activation of p38 protein kinase through ROS-induced stress response and p38 signaling is necessary for the action of PL as SB203580, a p38 inhibitor, or dominant-negative p38 can effectively reduce PL-mediated autophagy. Thus, we have characterized a new mechanism for PL-induced cell death through the ROS-p38 pathway. Our findings support the therapeutic potential of PL by triggering autophagic cell death. PMID:24091667

  14. Nanomaterials and Autophagy: New Insights in Cancer Treatment

    International Nuclear Information System (INIS)

    Autophagy represents a cell’s response to stress. It is an evolutionarily conserved process with diversified roles. Indeed, it controls intracellular homeostasis by degradation and/or recycling intracellular metabolic material, supplies energy, provides nutrients, eliminates cytotoxic materials and damaged proteins and organelles. Moreover, autophagy is involved in several diseases. Recent evidences support a relationship between several classes of nanomaterials and autophagy perturbation, both induction and blockade, in many biological models. In fact, the autophagic mechanism represents a common cellular response to nanomaterials. On the other hand, the dynamic nature of autophagy in cancer biology is an intriguing approach for cancer therapeutics, since during tumour development and therapy, autophagy has been reported to trigger both an early cell survival and a late cell death. The use of nanomaterials in cancer treatment to deliver chemotherapeutic drugs and target tumours is well known. Recently, autophagy modulation mediated by nanomaterials has become an appealing notion in nanomedicine therapeutics, since it can be exploited as adjuvant in chemotherapy or in the development of cancer vaccines or as a potential anti-cancer agent. Herein, we summarize the effects of nanomaterials on autophagic processes in cancer, also considering the therapeutic outcome of synergism between nanomaterials and autophagy to improve existing cancer therapies

  15. The regulation of autophagy during exercise in skeletal muscle.

    Science.gov (United States)

    Vainshtein, Anna; Hood, David A

    2016-03-15

    The merits of exercise on muscle health and well-being are numerous and well documented. However, the mechanisms underlying the robust adaptations induced by exercise, particularly on mitochondria, are less clear and much sought after. Recently, an evolutionary conserved cellular recycling mechanism known as autophagy has been implicated in the adaptations to acute and chronic exercise. A basal level of autophagy is constantly ongoing in cells and tissues, ensuring cellular clearance and energy homeostasis. This pathway can be further induced, as a survival mechanism, by cellular perturbations, such as energetic imbalance and oxidative stress. During exercise, a biphasic autophagy response is mobilized, leading to both an acute induction and a long-term potentiation of the process. Posttranslational modifications arising from upstream signaling cascades induce an acute autophagic response during a single bout of exercise by mobilizing core autophagy machinery. A transcriptional program involving the regulators Forkhead box O, transcription factor EB, p53, and peroxisome proliferator coactivator-1α is also induced to fuel sustained increases in autophagic capacity. Autophagy has also been documented to mediate chronic exercise-induced metabolic benefits, and animal models in which autophagy is perturbed do not adapt to exercise to the same extent. In this review, we discuss recent developments in the field of autophagy and exercise. We specifically highlight the molecular mechanisms activated during acute exercise that lead to a prolonged adaptive response. PMID:26679612

  16. Nanomaterials and Autophagy: New Insights in Cancer Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Panzarini, Elisa; Inguscio, Valentina; Tenuzzo, Bernardetta Anna; Carata, Elisabetta; Dini, Luciana, E-mail: luciana.dini@unisalento.it [Department of Biological and Environmental Science and Technology (Di.S.Te.B.A.), University of Salento, Lecce 73100 (Italy)

    2013-03-21

    Autophagy represents a cell’s response to stress. It is an evolutionarily conserved process with diversified roles. Indeed, it controls intracellular homeostasis by degradation and/or recycling intracellular metabolic material, supplies energy, provides nutrients, eliminates cytotoxic materials and damaged proteins and organelles. Moreover, autophagy is involved in several diseases. Recent evidences support a relationship between several classes of nanomaterials and autophagy perturbation, both induction and blockade, in many biological models. In fact, the autophagic mechanism represents a common cellular response to nanomaterials. On the other hand, the dynamic nature of autophagy in cancer biology is an intriguing approach for cancer therapeutics, since during tumour development and therapy, autophagy has been reported to trigger both an early cell survival and a late cell death. The use of nanomaterials in cancer treatment to deliver chemotherapeutic drugs and target tumours is well known. Recently, autophagy modulation mediated by nanomaterials has become an appealing notion in nanomedicine therapeutics, since it can be exploited as adjuvant in chemotherapy or in the development of cancer vaccines or as a potential anti-cancer agent. Herein, we summarize the effects of nanomaterials on autophagic processes in cancer, also considering the therapeutic outcome of synergism between nanomaterials and autophagy to improve existing cancer therapies.

  17. Transcriptional regulation of mammalian autophagy at a glance.

    Science.gov (United States)

    Füllgrabe, Jens; Ghislat, Ghita; Cho, Dong-Hyung; Rubinsztein, David C

    2016-08-15

    Macroautophagy, hereafter referred to as autophagy, is a catabolic process that results in the lysosomal degradation of cytoplasmic contents ranging from abnormal proteins to damaged cell organelles. It is activated  under diverse conditions, including nutrient deprivation and hypoxia. During autophagy, members of the core autophagy-related (ATG) family of proteins mediate membrane rearrangements, which lead to the engulfment and degradation of cytoplasmic cargo. Recently, the nuclear regulation of autophagy, especially by transcription factors and histone modifiers, has gained increased attention. These factors are not only involved in rapid responses to autophagic stimuli, but also regulate the long-term outcome of autophagy. Now there are more than 20 transcription factors that have been shown to be linked to the autophagic process. However, their interplay and timing appear enigmatic as several have been individually shown to act as major regulators of autophagy. This Cell Science at a Glance article and the accompanying poster highlights the main cellular regulators of transcription involved in mammalian autophagy and their target genes. PMID:27528206

  18. Autophagy in the immune response to tuberculosis: clinical perspectives.

    LENUS (Irish Health Repository)

    Ní Cheallaigh, C

    2011-06-01

    A growing body of evidence points to autophagy as an essential component in the immune response to tuberculosis. Autophagy is a direct mechanism of killing intracellular Mycobacterium tuberculosis and also acts as a modulator of proinflammatory cytokine secretion. In addition, autophagy plays a key role in antigen processing and presentation. Autophagy is modulated by cytokines; it is stimulated by T helper type 1 (Th1) cytokines such as tumour necrosis factor (TNF)-α and interferon (IFN)-γ, and is inhibited by the Th2 cytokines interleukin (IL)-4 and IL-13 and the anti-inflammatory cytokine IL-10. Vitamin D, via cathelicidin, can also induce autophagy, as can Toll-like receptor (TLR)-mediated signals. Autophagy-promoting agents, administered either locally to the lungs or systemically, could have a clinical application as adjunctive treatment of drug-resistant and drug-sensitive tuberculosis. Moreover, vaccines which effectively induce autophagy could be more successful in preventing acquisition or reactivation of latent tuberculosis.

  19. Function of Autophagy in Nonalcoholic Fatty Liver Disease.

    Science.gov (United States)

    Czaja, Mark J

    2016-05-01

    Autophagy is a lysosomal degradative pathway that functions to promote cell survival by supplying energy in times of stress or by removing damaged organelles and proteins after injury. The involvement of autophagy in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) was first suggested by the finding that this pathway mediates the breakdown of intracellular lipids in hepatocytes and therefore may regulate the development of hepatic steatosis. Subsequent studies have demonstrated additional critical functions for autophagy in hepatocytes and other hepatic cell types such as macrophages and stellate cells that regulate insulin sensitivity, hepatocellular injury, innate immunity, fibrosis, and carcinogenesis. These findings suggest a number of possible mechanistic roles for autophagy in the development of NAFLD and progression to NASH and its complications. The functions of autophagy in the liver, together with findings of decreased hepatic autophagy in association with conditions that predispose to NAFLD such as obesity and aging, suggest that autophagy may be a novel therapeutic target in this disease. PMID:26725058

  20. Folate deprivation modulates the expression of autophagy- and circadian-related genes in HT-22 hippocampal neuron cells through GR-mediated pathway.

    Science.gov (United States)

    Sun, Qinwei; Yang, Yang; Li, Xi; He, Bin; Jia, Yimin; Zhang, Nana; Zhao, Ruqian

    2016-08-01

    Folic acid (FA) is an extremely important nutrient for brain formation and development. FA deficiency is highly linked to brain degeneration and age-related diseases, which are also associated with autophagic activities and circadian rhythm in hippocampal neurons. However, little is known how autophagy- and circadian-related genes in hippocampal neurons are regulated under FA deficiency. Here, hippocampal neuroncells (HT-22) were employed to determine the effect of FA deprivation (FD) on the expression of relevant genes and to reveal the potential role of glucocorticoid receptor (GR). FD increased autophagic activities in HT-22 cells, associated with significantly (PChIP assay showed that FD promoted (Pnetwork in response to folate deficiency. PMID:27133904

  1. The lack of autophagy triggers precocious activation of Notch signaling during Drosophila oogenesis

    Directory of Open Access Journals (Sweden)

    Barth Julia MI

    2012-12-01

    Full Text Available Abstract Background The proper balance of autophagy, a lysosome-mediated degradation process, is indispensable for oogenesis in Drosophila. We recently demonstrated that egg development depends on autophagy in the somatic follicle cells (FC, but not in the germline cells (GCs. However, the lack of autophagy only affects oogenesis when FCs are autophagy-deficient but GCs are wild type, indicating that a dysfunctional signaling between soma and germline may be responsible for the oogenesis defects. Thus, autophagy could play an essential role in modulating signal transduction pathways during egg development. Results Here, we provide further evidence for the necessity of autophagy during oogenesis and demonstrate that autophagy is especially required in subsets of FCs. Generation of autophagy-deficient FCs leads to a wide range of phenotypes that are similar to mutants with defects in the classical cell-cell signaling pathways in the ovary. Interestingly, we observe that loss of autophagy leads to a precocious activation of the Notch pathway in the FCs as monitored by the expression of Cut and Hindsight, two downstream effectors of Notch signaling. Conclusion Our findings point to an unexpected function for autophagy in the modulation of the Notch signaling pathway during Drosophila oogenesis and suggest a function for autophagy in proper receptor activation. Egg development is affected by an imbalance of autophagy between signal sending (germline and signal receiving cell (FC, thus the lack of autophagy in the germline is likely to decrease the amount of active ligand and accordingly compensates for increased signaling in autophagy-defective follicle cells.

  2. The impact of autophagy on peripheral synapses in health and disease.

    Science.gov (United States)

    Rudolf, Rudiger; Khan, Muzamil Majid; Wild, Franziska; Hashemolhosseini, Said

    2016-01-01

    Alterations of autophagy have been linked to several peripheral nervous system diseases, such as amyotrophic lateral sclerosis and Charcot-Marie-Tooth disease. Modulation of autophagy by metabolic or pharmacological interventions has been increasingly recognized as a strategy to fight many of these disorders. Cellular processes that are aberrant in case of impaired autophagy and that might lead to these diseases belong to three different categories: (1) clearing of protein aggregates, (2) regulation of vesicle and cargo turnover, and (3) disposal of damaged mitochondria. This review summarizes the present literature that addresses both, the impact and mechanisms of autophagy on the health of the peripheral nervous system and treatment proposals for human disorders associated with impaired autophagy. PMID:27100517

  3. Autophagy regulates endothelial cell processing, maturation and secretion of von Willebrand factor

    OpenAIRE

    Torisu, Takehiro; Torisu, Kumiko; Lee, In Hye; Liu, Jie; Malide, Daniela; Combs, Christian A.; Wu, Xufeng S.; Rovira, Ilsa I.; Fergusson, Maria M; Weigert, Roberto; Connelly, Patricia S.; Daniels, Mathew P.; Komatsu, Masaaki; Cao, Liu; Finkel, Toren

    2013-01-01

    Endothelial secretion of von Willebrand factor (VWF) from intracellular organelles known as Weibel-Palade bodies (WPBs) is required for platelet adhesion to the injured vessel wall. Here, we demonstrate that WPBs are in some cases found near or within autophagosomes and that endothelial autophagosomes contain abundant VWF protein. Pharmacological inhibitors of autophagy, or knockdown of the essential autophagy genes Atg5 or Atg7, inhibits the in vitro secretion of VWF. Furthermore, while mice...

  4. Autophagy contributes to gefitinib-induced glioma cell growth inhibition

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Cheng-Yi [Department of Surgery, Fong-Yuan Hospital, Taichung 420, Taiwan (China); Graduate Institute of Pharmaceutical Science and Technology, Central Taiwan University of Science and Technology, Taichung 406, Taiwan (China); Kuan, Yu-Hsiang [Department of Pharmacology, School of Medicine, Chung Shan Medical University, Taichung 402, Taiwan (China); Department of Pharmacy, Chung Shan Medical University Hospital, Taichung 402, Taiwan (China); Ou, Yen-Chuan; Li, Jian-Ri [Division of Urology, Taichung Veterans General Hospital, Taichung 407, Taiwan (China); Wu, Chih-Cheng [Department of Anesthesiology, Taichung Veterans General Hospital, Taichung 407, Taiwan (China); Department of Financial and Computational Mathematics, Providence University, Taichung 433, Taiwan (China); Pan, Pin-Ho [Department of Pediatrics, Tungs’ Taichung MetroHarbor Hospital, Taichung 435, Taiwan (China); Chen, Wen-Ying [Department of Veterinary Medicine, National Chung Hsing University, Taichung 402, Taiwan (China); Huang, Hsuan-Yi [Department of Surgery, Fong-Yuan Hospital, Taichung 420, Taiwan (China); Chen, Chun-Jung, E-mail: cjchen@vghtc.gov.tw [Department of Medical Research, Taichung Veterans General Hospital, Taichung 407, Taiwan (China); Institute of Biomedical Sciences, National Chung Hsing University, Taichung 402, Taiwan (China); Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung 402, Taiwan (China); Center for General Education, Tunghai University, Taichung 407, Taiwan (China); Department of Nursing, HungKuang University, Taichung 433, Taiwan (China)

    2014-09-10

    Epidermal growth factor receptor tyrosine kinase inhibitors, including gefitinib, have been evaluated in patients with malignant gliomas. However, the molecular mechanisms involved in gefitinib-mediated anticancer effects against glioma are incompletely understood. In the present study, the cytostatic potential of gefitinib was demonstrated by the inhibition of glioma cell growth, long-term clonogenic survival, and xenograft tumor growth. The cytostatic consequences were accompanied by autophagy, as evidenced by monodansylcadaverine staining of acidic vesicle formation, conversion of microtubule-associated protein-1 light chain 3-II (LC3-II), degradation of p62, punctate pattern of GFP-LC3, and conversion of GFP-LC3 to cleaved-GFP. Autophagy inhibitor 3-methyladenosine and chloroquine and genetic silencing of LC3 or Beclin 1 attenuated gefitinib-induced growth inhibition. Gefitinib-induced autophagy was not accompanied by the disruption of the Akt/mammalian target of rapamycin signaling. Instead, the activation of liver kinase-B1/AMP-activated protein kinase (AMPK) signaling correlated well with the induction of autophagy and growth inhibition caused by gefitinib. Silencing of AMPK suppressed gefitinib-induced autophagy and growth inhibition. The crucial role of AMPK activation in inducing glioma autophagy and growth inhibition was further supported by the actions of AMP mimetic AICAR. Gefitinib was shown to be capable of reducing the proliferation of glioma cells, presumably by autophagic mechanisms involving AMPK activation. - Highlights: • Gefitinib causes cytotoxic and cytostatic effect on glioma. • Gefitinib induces autophagy. • Gefitinib causes cytostatic effect through autophagy. • Gefitinib induces autophagy involving AMPK.

  5. Autophagy contributes to gefitinib-induced glioma cell growth inhibition

    International Nuclear Information System (INIS)

    Epidermal growth factor receptor tyrosine kinase inhibitors, including gefitinib, have been evaluated in patients with malignant gliomas. However, the molecular mechanisms involved in gefitinib-mediated anticancer effects against glioma are incompletely understood. In the present study, the cytostatic potential of gefitinib was demonstrated by the inhibition of glioma cell growth, long-term clonogenic survival, and xenograft tumor growth. The cytostatic consequences were accompanied by autophagy, as evidenced by monodansylcadaverine staining of acidic vesicle formation, conversion of microtubule-associated protein-1 light chain 3-II (LC3-II), degradation of p62, punctate pattern of GFP-LC3, and conversion of GFP-LC3 to cleaved-GFP. Autophagy inhibitor 3-methyladenosine and chloroquine and genetic silencing of LC3 or Beclin 1 attenuated gefitinib-induced growth inhibition. Gefitinib-induced autophagy was not accompanied by the disruption of the Akt/mammalian target of rapamycin signaling. Instead, the activation of liver kinase-B1/AMP-activated protein kinase (AMPK) signaling correlated well with the induction of autophagy and growth inhibition caused by gefitinib. Silencing of AMPK suppressed gefitinib-induced autophagy and growth inhibition. The crucial role of AMPK activation in inducing glioma autophagy and growth inhibition was further supported by the actions of AMP mimetic AICAR. Gefitinib was shown to be capable of reducing the proliferation of glioma cells, presumably by autophagic mechanisms involving AMPK activation. - Highlights: • Gefitinib causes cytotoxic and cytostatic effect on glioma. • Gefitinib induces autophagy. • Gefitinib causes cytostatic effect through autophagy. • Gefitinib induces autophagy involving AMPK

  6. Role of autophagy in differential sensitivity of hepatocarcinoma cells to sorafenib

    Institute of Scientific and Technical Information of China (English)

    Trevan; D; Fischer; Jin-Hee; Wang; Adrian; Vlada; Jae-Sung; Kim; Kevin; E; Behrns

    2014-01-01

    AIM: To investigate the role of sorafenib(SFN) in autophagy of hepatocellular carcinoma(HCC). We evaluated how SFN affects autophagy signaling pathway in human HCC cell lines. METHODS: Two different human HCC cell lines, Hep3 B and Huh7, were subjected to different concentrations of SFN. Cell viability and onset of apoptosis were determined with colorimetric assay and immunoblotting analysis, respectively. The changes in autophagy-related proteins, including LC3, ULK1, AMPK, and LKB, were determined with immunoblotting analysis in the presence or absence of SFN. To assess autophagic dynamics, autophagic flux was measured with chloroquine, a lysosomal inhibitor. The autophagic responsiveness between different HCC cell lines was compared under the autophagy enhancing conditions.RESULTS: Hep3 B cells were significantly more resistant to SFN than Huh7 cells. Immunoblotting analysis revealed a marked increase in SFN-mediated autophagy flux in Huh7 cells, which was, however, absent in Hep3 B cells. While both starvation and rapamycin enhanced autophagy in Huh7 cells, only rapamycin increased autophagy in Hep3 B cells. Immunoblotting analysis of autophagy initiation proteins showed that SFN substantially increased phosphorylation of AMPK and consequently autophagy in Huh7, but not in Hep3 B cells.CONCLUSION: The autophagic responsiveness to SFN is distinct between Hep3 B and Huh7 cells. Resistance of Hep3 B cells to SFN may be associated with altered autophagy signaling pathways.

  7. Calcium Homeostasis and ER Stress in Control of Autophagy in Cancer Cells

    Directory of Open Access Journals (Sweden)

    Elżbieta Kania

    2015-01-01

    Full Text Available Autophagy is a basic catabolic process, serving as an internal engine during responses to various cellular stresses. As regards cancer, autophagy may play a tumor suppressive role by preserving cellular integrity during tumor development and by possible contribution to cell death. However, autophagy may also exert oncogenic effects by promoting tumor cell survival and preventing cell death, for example, upon anticancer treatment. The major factors influencing autophagy are Ca2+ homeostasis perturbation and starvation. Several Ca2+ channels like voltage-gated T- and L-type channels, IP3 receptors, or CRAC are involved in autophagy regulation. Glucose transporters, mainly from GLUT family, which are often upregulated in cancer, are also prominent targets for autophagy induction. Signals from both Ca2+ perturbations and glucose transport blockage might be integrated at UPR and ER stress activation. Molecular pathways such as IRE 1-JNK-Bcl-2, PERK-eIF2α-ATF4, or ATF6-XBP 1-ATG are related to autophagy induced through ER stress. Moreover ER molecular chaperones such as GRP78/BiP and transcription factors like CHOP participate in regulation of ER stress-mediated autophagy. Autophagy modulation might be promising in anticancer therapies; however, it is a context-dependent matter whether inhibition or activation of autophagy leads to tumor cell death.

  8. Intestinal Autophagy Improves Healthspan and Longevity in C. elegans during Dietary Restriction.

    Directory of Open Access Journals (Sweden)

    Sara Gelino

    2016-07-01

    Full Text Available Dietary restriction (DR is a dietary regimen that extends lifespan in many organisms. One mechanism contributing to the conserved effect of DR on longevity is the cellular recycling process autophagy, which is induced in response to nutrient scarcity and increases sequestration of cytosolic material into double-membrane autophagosomes for degradation in the lysosome. Although autophagy plays a direct role in DR-mediated lifespan extension in the nematode Caenorhabditis elegans, the contribution of autophagy in individual tissues remains unclear. In this study, we show a critical role for autophagy in the intestine, a major metabolic tissue, to ensure lifespan extension of dietary-restricted eat-2 mutants. The intestine of eat-2 mutants has an enlarged lysosomal compartment and flux assays indicate increased turnover of autophagosomes, consistent with an induction of autophagy in this tissue. This increase in intestinal autophagy may underlie the improved intestinal integrity we observe in eat-2 mutants, since whole-body and intestinal-specific inhibition of autophagy in eat-2 mutants greatly impairs the intestinal barrier function. Interestingly, intestinal-specific inhibition of autophagy in eat-2 mutants leads to a decrease in motility with age, alluding to a potential cell non-autonomous role for autophagy in the intestine. Collectively, these results highlight important functions for autophagy in the intestine of dietary-restricted C. elegans.

  9. Inhibition of peroxynitrite-mediated DNA strand cleavage and hydroxyl radical formation by aspirin at pharmacologically relevant concentrations: Implications for cancer intervention

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei [Division of Biomedical Sciences, Edward Via Virginia College of Osteopathic Medicine, Virginia Tech Corporate Research Center, Blacksburg, VA 24060 (United States); College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310035 (China); Department of Food Science and Technology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States); Zhu, Hong; Jia, Zhenquan [Division of Biomedical Sciences, Edward Via Virginia College of Osteopathic Medicine, Virginia Tech Corporate Research Center, Blacksburg, VA 24060 (United States); Li, Jianrong [College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou 310035 (China); Misra, Hara P. [Division of Biomedical Sciences, Edward Via Virginia College of Osteopathic Medicine, Virginia Tech Corporate Research Center, Blacksburg, VA 24060 (United States); Zhou, Kequan, E-mail: kzhou@wayne.edu [Department of Nutrition and Food Science, Wayne State University, Detroit, MI 48202 (United States); Li, Yunbo, E-mail: yli@vcom.vt.edu [Division of Biomedical Sciences, Edward Via Virginia College of Osteopathic Medicine, Virginia Tech Corporate Research Center, Blacksburg, VA 24060 (United States)

    2009-12-04

    Epidemiological studies have suggested that the long-term use of aspirin is associated with a decreased incidence of human malignancies, especially colorectal cancer. Since accumulating evidence indicates that peroxynitrite is critically involved in multistage carcinogenesis, this study was undertaken to investigate the ability of aspirin to inhibit peroxynitrite-mediated DNA damage. Peroxynitrite and its generator 3-morpholinosydnonimine (SIN-1) were used to cause DNA strand breaks in {phi}X-174 plasmid DNA. We demonstrated that the presence of aspirin at concentrations (0.25-2 mM) compatible with amounts in plasma during chronic anti-inflammatory therapy resulted in a significant inhibition of DNA cleavage induced by both peroxynitrite and SIN-1. Moreover, the consumption of oxygen caused by 250 {mu}M SIN-1 was found to be decreased in the presence of aspirin, indicating that aspirin might affect the auto-oxidation of SIN-1. Furthermore, EPR spectroscopy using 5,5-dimethylpyrroline-N-oxide (DMPO) as a spin trap demonstrated the formation of DMPO-hydroxyl radical adduct (DMPO-OH) from authentic peroxynitrite, and that aspirin at 0.25-2 mM potently diminished the radical adduct formation in a concentration-dependent manner. Taken together, these results demonstrate for the first time that aspirin at pharmacologically relevant concentrations can inhibit peroxynitrite-mediated DNA strand breakage and hydroxyl radical formation. These results may have implications for cancer intervention by aspirin.

  10. Inhibition of peroxynitrite-mediated DNA strand cleavage and hydroxyl radical formation by aspirin at pharmacologically relevant concentrations: Implications for cancer intervention

    International Nuclear Information System (INIS)

    Epidemiological studies have suggested that the long-term use of aspirin is associated with a decreased incidence of human malignancies, especially colorectal cancer. Since accumulating evidence indicates that peroxynitrite is critically involved in multistage carcinogenesis, this study was undertaken to investigate the ability of aspirin to inhibit peroxynitrite-mediated DNA damage. Peroxynitrite and its generator 3-morpholinosydnonimine (SIN-1) were used to cause DNA strand breaks in φX-174 plasmid DNA. We demonstrated that the presence of aspirin at concentrations (0.25-2 mM) compatible with amounts in plasma during chronic anti-inflammatory therapy resulted in a significant inhibition of DNA cleavage induced by both peroxynitrite and SIN-1. Moreover, the consumption of oxygen caused by 250 μM SIN-1 was found to be decreased in the presence of aspirin, indicating that aspirin might affect the auto-oxidation of SIN-1. Furthermore, EPR spectroscopy using 5,5-dimethylpyrroline-N-oxide (DMPO) as a spin trap demonstrated the formation of DMPO-hydroxyl radical adduct (DMPO-OH) from authentic peroxynitrite, and that aspirin at 0.25-2 mM potently diminished the radical adduct formation in a concentration-dependent manner. Taken together, these results demonstrate for the first time that aspirin at pharmacologically relevant concentrations can inhibit peroxynitrite-mediated DNA strand breakage and hydroxyl radical formation. These results may have implications for cancer intervention by aspirin.

  11. Interference with HMGB1 increases the sensitivity to chemotherapy drugs by inhibiting HMGB1-mediated cell autophagy and inducing cell apoptosis.

    Science.gov (United States)

    Zhang, Ruiguang; Li, Yan; Wang, Zhongliang; Chen, Lingjuan; Dong, Xiaorong; Nie, Xiu

    2015-11-01

    Non-small cell lung cancer is commonly seen with higher morbidity and mortality. High-mobility group protein 1 (HMGB1) is a highly conserved nuclear protein, which is involved in multiple human diseases including cancers. However, the mechanisms of HMGB1 in non-small cell lung cancer remain unclear. The goal of the present study is to identify the relationship between HMGB1 and the progresssion of non-small cell lung cancer and investigate the molecular mechanism of HMGB1 in non-small lung cancer cell lines. Firstly, we detected the expression levels of HMGB1 by by real-time PCR and western blotting analysis, and the results demonstrated that HMGB1 was much higher expressed in non-small cell lung cancer cell lines, including A549, SPC-1-1, NCI-2170, SK-MES-1, and NCI-H1299, compared with that of WI-38. Next, 5 μM of adriamycin (AMD), 20 μM of cisplatin (DDP), and 50 μM of methotrexate (MTX) were used to treat A549 cells and SPC-A-1 cells for 48 h. The results showed that treatment with chemotherapy drugs significantly increased the levels of HMGB1 in A549 cells and SPC-A-1 cells. Moreover, the expression levels of HMGB1 increased in a time-dependent manner being treated with DDP. Then, the endogenous HMGB1 expression was successfully interferred with shRNA specific to HMGB1 in A549 and SPC-A-1 cells, which was detected by western blotting analysis. Then, the cisplatin-sensitive A549 cells and cisplatin-resistant A549/DDP cells were treated with increasing concentrations of cisplatin for 24, 48, and 72 h; cell viability were analyzed by MTT assay; and IC50 values were calculated. The results demonstrated that the expression level of HMGB1 in A549/DDP cells was much higher than that of A549 cells; moreover, transfection with HMGB1 shRNA in A549/DDP cells decreased the IC50 value of cisplatin in A549/DDP cells. The expression levels of autophagy-related proteins beclin-1 and LC3-II were significantly higher in A549/DDP cells or the A549 cells treated with

  12. Autophagy in cerebral ischemia and the effects of traditional Chinese medicine

    Institute of Scientific and Technical Information of China (English)

    Xiao-ping Huang; Huang Ding; Jin-dong Lu; Ying-hong Tang; Bing-xiang Deng; Chang-qing Deng

    2015-01-01

    Autophagy is a lysosome-mediated degradation process for non-essential or damaged celular constituents, playing an important homeostatic role in cel survival, differentiation and development to maintain homeostasis. Autophagy is involved in tumors as wel as neurodegenerative, cardiovascular and cerebrovascular diseases. Recently, active compounds from traditional Chinese medicine (TCM) have been found to modulate the levels of autophagy in tumor cels, nerve cels, myocardial cels and endothelial cels. Ischemic stroke is a major cause of neurological disability and places a heavy burden on family and society. Regaining function can signiifcantly reduce dependence and improve the quality of life of stroke survivors. In healthy cels, autophagy plays a key role in adapting to nutritional deprivation and eliminating aggregated proteins, however inappropriate activation of autophagy may lead to cel death in cerebral ischemia. This paper reviews the process and the molecular basis of autophagy, as wel as its roles in cerebral ischemia and the roles of TCM in modulating its activity.

  13. Enhanced autophagy as a potential mechanism for the improved physiological function by simvastatin in muscular dystrophy.

    Science.gov (United States)

    Whitehead, Nicholas P

    2016-04-01

    Autophagy has recently emerged as an important cellular process for the maintenance of skeletal muscle health and function. Excessive autophagy can trigger muscle catabolism, leading to atrophy. In contrast, reduced autophagic flux is a characteristic of several muscle diseases, including Duchenne muscular dystrophy, the most common and severe inherited muscle disorder. Recent evidence demonstrates that enhanced reactive oxygen species (ROS) production by CYBB/NOX2 impairs autophagy in muscles from the dmd/mdx mouse, a genetic model of Duchenne muscular dystrophy. Statins decrease CYBB/NOX2 expression and activity and stimulate autophagy in skeletal muscle. Therefore, we treated dmd/mdx mice with simvastatin and showed decreased CYBB/NOX2-mediated oxidative stress and enhanced autophagy induction. This was accompanied by reduced muscle damage, inflammation and fibrosis, and increased muscle force production. Our data suggest that increased autophagy may be a potential mechanism by which simvastatin improves skeletal muscle health and function in muscular dystrophy. PMID:26890413

  14. Pharmacology and toxicology of fibrates as hypolipidemic drugs mediated by nuclear receptor peroxisome proliferator—activated receptor

    Institute of Scientific and Technical Information of China (English)

    SugaT

    2002-01-01

    PPAR(peroxisome proliferator-activated receptor) is a family of nuclear receptor.In recent years,it has been focused for the discovery and development of new drugs which are mediated by PPARs.Fibrate hypolipidemic drugs are the specific and potent ligands to PPAR alpha and have been widely used for the treatment of hyperlipidemia.But these drugs induce hepatocarcinogenesis in rodent animals after the long-term administration.However,there are species differences on these phenomena which are not seen in mammals ioncluding human.To clarify the mechanism of carcinogenesis by these drugs in important for the evaluation of safety of these drugs in human.

  15. SIRT6 suppresses isoproterenol-induced cardiac hypertrophy through activation of autophagy.

    Science.gov (United States)

    Lu, Jing; Sun, Duanping; Liu, Zhiping; Li, Min; Hong, Huiqi; Liu, Cui; Gao, Si; Li, Hong; Cai, Yi; Chen, Shaorui; Li, Zhuoming; Ye, Jiantao; Liu, Peiqing

    2016-06-01

    Reduction in autophagy has been reported to contribute to the pathogenesis of cardiac hypertrophy. However, the molecular pathways leading to impaired autophagy at the presence of hypertrophic stimuli remain to be elucidated. The present study aimed to investigate the role of sirtuin 6 (SIRT6), a sirtuin family member, in regulating cardiomyocyte autophagy, and its implication in prevention of cardiac hypertrophy. Primary neonatal rat cardiomyocytes (NRCMs) or Sprague-Dawley (SD) rats were submitted to isoproterenol (ISO) treatment, and then the hypertrophic responses and changes in autophagy activity were measured. The influence of SIRT6 on autophagy was observed in cultured NRCMs with gain- and loss-of-function approaches to regulate SIRT6 expression, and further confirmed in vivo by intramyocardial delivery of an adenovirus vector encoding SIRT6 cDNA. In addition, the involvement of SIRT6-mediated autophagy in attenuation of cardiomyocyte hypertrophy induced by ISO was determined basing on genetic or pharmaceutical disruption of autophagy, and the underlying mechanism was preliminarily explored. ISO-caused cardiac hypertrophy accompanying with a significant decrease in autophagy activity. SIRT6 overexpression enhanced autophagy in NRCMs and in rat hearts, whereas knockdown of SIRT6 by RNA interference led to suppression of cardiomyocyte autophagy. Furthermore, the protective effect of SIRT6 against ISO-stimulated hypertrophy was associated with induction of autophagy. SIRT6 promoted nuclear retention of forkhead box O3 transcription factor possibly via attenuating Akt signaling, which was responsible for autophagy activation. Our findings revealed that SIRT6 positively regulates autophagy in cardiomyocytes, which may help to ameliorate ISO-induced cardiac hypertrophy. PMID:27016702

  16. Pharmacological evidence for the mediation of the panicolytic effect of fluoxetine by dorsal periaqueductal gray matter μ-opioid receptors.

    Science.gov (United States)

    Roncon, Camila Marroni; Almada, Rafael Carvalho; Maraschin, Jhonatan Christian; Audi, Elisabeth Aparecida; Zangrossi, Hélio; Graeff, Frederico Guilherme; Coimbra, Norberto Cysne

    2015-12-01

    Previously reported results have shown that the inhibitory effect of fluoxetine on escape behavior, interpreted as a panicolytic-like effect, is blocked by pretreatment with either the opioid receptor antagonist naloxone or the 5-HT1A receptor (5-HT1A-R) antagonist WAY100635 via injection into the dorsal periaqueductal gray matter (dPAG). Additionally, reported evidence indicates that the μ-opioid receptor (MOR) interacts with the 5-HT1A-R in the dPAG. In the present work, pretreatment of the dPAG with the selective MOR blocker CTOP antagonized the anti-escape effect of chronic fluoxetine (10 mg/kg, i.p., daily, for 21 days), as measured in the elevated T-maze (ETM) test, indicating mediation of this effect by the MOR. In addition, the combined administration of sub-effective doses of the selective MOR agonist DAMGO (intra-dPAG) and sub-effective doses of chronic as well as subchronic (7 days) fluoxetine increased avoidance and escape latencies, suggesting that the activation of MORs may facilitate and accelerate the effects of fluoxetine. The current observation that MORs located in the dPAG mediate the anti-escape effect of fluoxetine may open new perspectives for the development of more efficient and fast-acting panic-alleviating drugs. PMID:26320545

  17. A dual function for Deep orange in programmed autophagy in the Drosophila melanogaster fat body

    International Nuclear Information System (INIS)

    Lysosomal degradation of cytoplasm by way of autophagy is essential for cellular amino acid homeostasis and for tissue remodeling. In insects such as Drosophila, autophagy is developmentally upregulated in the larval fat body prior to metamorphosis. Here, autophagy is induced by the hormone ecdysone through down-regulation of the autophagy-suppressive phosphoinositide 3-kinase (PI3K) signaling pathway. In yeast, Vps18 and other members of the HOPS complex have been found essential for autophagic degradation. In Drosophila, the Vps18 homologue Deep orange (Dor) has previously been shown to mediate fusion of multivesicular endosomes with lysosomes. A requirement of Dor for ecdysone-mediated chromosome puffing has also been reported. In the present report, we have tested the hypothesis that Dor may control programmed autophagy at the level of ecdysone signaling as well as by mediating autophagosome-to-lysosome fusion. We show that dor mutants are defective in programmed autophagy and provide evidence that autophagy is blocked at two levels. First, PI3K activity was not down-regulated correctly in dor larvae, which correlated with a decrease in ecdysone reporter activity. The down-regulation of PI3K activity was restored by feeding ecdysone to the mutant larvae. Second, neither exogenous ecdysone nor overexpression of PTEN, a silencer of PI3K signaling, restored fusion of autophagosomes with lysosomes in the fat body of dor mutants. These results indicate that Dor controls autophagy indirectly, via ecdysone signaling, as well as directly, via autolysosomal fusion

  18. The thiazole derivative CPTH6 impairs autophagy.

    Science.gov (United States)

    Ragazzoni, Y; Desideri, M; Gabellini, C; De Luca, T; Carradori, S; Secci, D; Nescatelli, R; Candiloro, A; Condello, M; Meschini, S; Del Bufalo, D; Trisciuoglio, D

    2013-01-01

    We have previously demonstrated that the thiazole derivative 3-methylcyclopentylidene-[4-(4'-chlorophenyl)thiazol-2-yl]hydrazone (CPTH6) induces apoptosis and cell cycle arrest in human leukemia cells. The aim of this study was to evaluate whether CPTH6 is able to affect autophagy. By using several human tumor cell lines with different origins we demonstrated that CPTH6 treatment induced, in a dose-dependent manner, a significant increase in autophagic features, as imaged by electron microscopy, immunoblotting analysis of membrane-bound form of microtubule-associated protein 1 light chain 3 (LC3B-II) levels and by appearance of typical LC3B-II-associated autophagosomal puncta. To gain insights into the molecular mechanisms of elevated markers of autophagy induced by CPTH6 treatment, we silenced the expression of several proteins acting at different steps of autophagy. We found that the effect of CPTH6 on autophagy developed through a noncanonical mechanism that did not require beclin-1-dependent nucleation, but involved Atg-7-mediated elongation of autophagosomal membranes. Strikingly, a combined treatment of CPTH6 with late-stage autophagy inhibitors, such as chloroquine and bafilomycin A1, demonstrates that under basal condition CPTH6 reduces autophagosome turnover through an impairment of their degradation pathway, rather than enhancing autophagosome formation, as confirmed by immunofluorescence experiments. According to these results, CPTH6-induced enhancement of autophagy substrate p62 and NBR1 protein levels confirms a blockage of autophagic cargo degradation. In addition, CPTH6 inhibited autophagosome maturation and compounds having high structural similarities with CPTH6 produced similar effects on the autophagic pathway. Finally, the evidence that CPTH6 treatment decreased α-tubulin acetylation and failed to increase autophagic markers in cells in which acetyltransferase ATAT1 expression was silenced indicates a possible role of α-tubulin acetylation in

  19. Graphene quantum dots induce apoptosis, autophagy, and inflammatory response via p38 mitogen-activated protein kinase and nuclear factor-κB mediated signaling pathways in activated THP-1 macrophages

    International Nuclear Information System (INIS)

    The biomedical application of graphene quantum dots (GQDs) is a new emerging area. However, their safety data are still in scarcity to date. Particularly, the effect of GQDs on the immune system remains unknown. This study aimed to elucidate the interaction of GQDs with macrophages and the underlying mechanisms. Our results showed that GQDs slightly affected the cell viability and membrane integrity of macrophages, whereas GQDs significantly increased reactive oxygen species (ROS) generation and apoptotic and autophagic cell death with an increase in the expression level of Bax, Bad, caspase 3, caspase 9, beclin 1, and LC3-I/II and a decrease in that of Bcl-2. Furthermore, low concentrations of GQDs significantly increased the expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-8, whereas high concentrations of GQDs elicited opposite effects on the cytokines production. SB202190, a selective inhibitor of p38 mitogen-activated protein kinase (MAPK), abolished the cytokine-inducing effect of GQDs in macrophages. Moreover, GQDs significantly increased the phosphorylation of p38 MAPK and p65, and promoted the nuclear translocation of nuclear factor-κB (NF-κB). Taken together, these results show that GQDs induce ROS generation, apoptosis, autophagy, and inflammatory response via p38MAPK and NF-κB mediated signaling pathways in THP-1 activated macrophages

  20. Association of FKBP51 with priming of autophagy pathways and mediation of antidepressant treatment response: evidence in cells, mice, and humans.

    Directory of Open Access Journals (Sweden)

    Nils C Gassen

    2014-11-01

    Full Text Available BACKGROUND: FK506 binding protein 51 (FKBP51 is an Hsp90 co-chaperone and regulator of the glucocorticoid receptor, and consequently of stress physiology. Clinical studies suggest a genetic link between FKBP51 and antidepressant response in mood disorders; however, the underlying mechanisms remain elusive. The objective of this study was to elucidate the role of FKBP51 in the actions of antidepressants, with a particular focus on pathways of autophagy. METHODS AND FINDINGS: Established cell lines, primary neural cells, human blood cells of healthy individuals and patients with depression, and mice were treated with antidepressants. Mice were tested for several neuroendocrine and behavioral parameters. Protein interactions and autophagic pathway activity were mainly evaluated by co-immunoprecipitation and Western blots. We first show that the effects of acute antidepressant treatment on behavior are abolished in FKBP51 knockout (51KO mice. Autophagic markers, such as the autophagy initiator Beclin1, were increased following acute antidepressant treatment in brains from wild-type, but not 51KO, animals. FKBP51 binds to Beclin1, changes decisive protein interactions and phosphorylation of Beclin1, and triggers autophagic pathways. Antidepressants and FKBP51 exhibited synergistic effects on these pathways. Using chronic social defeat as a depression-relevant stress model in combination with chronic paroxetine (PAR treatment revealed that the stress response, as well as the effects of antidepressants on behavior and autophagic markers, depends on FKBP51. In human blood cells of healthy individuals, FKBP51 levels correlated with the potential of antidepressants to induce autophagic pathways. Importantly, the clinical antidepressant response of patients with depression (n = 51 could be predicted by the antidepressant response of autophagic markers in patient-derived peripheral blood lymphocytes cultivated and treated ex vivo (Beclin1/amitriptyline: r

  1. Heme oxygenase-1 enhances autophagy in podocytes as a protective mechanism against high glucose-induced apoptosis

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Chenglong [Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing (China); Zheng, Haining [Department of Hyperbaric Oxygen, Nanjing General Hospital of Nanjing Military Command, Nanjing (China); Huang, Shanshan; You, Na; Xu, Jiarong; Ye, Xiaolong; Zhu, Qun; Feng, Yamin; You, Qiang; Miao, Heng [Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing (China); Ding, Dafa, E-mail: dingdafa2004@aliyun.com [Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing (China); Lu, Yibing, E-mail: luyibing2004@126.com [Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing (China)

    2015-10-01

    Injury and loss of podocytes play vital roles in diabetic nephropathy progression. Emerging evidence suggests autophagy, which is induced by multiple stressors including hyperglycemia, plays a protective role. Meanwhile, heme oxygenase-1 (HO-1) possesses powerful anti-apoptotic properties. Therefore, we investigated the impact of autophagy on podocyte apoptosis under diabetic conditions and its association with HO-1. Mouse podocytes were cultured in vitro; apoptosis was detected by flow cytometry. Transmission electron microscopy and biochemical autophagic flux assays were used to measure the autophagy markers microtubule-associated protein 1 light chain 3-II (LC3-II) and beclin-1. LC3-II and beclin-1 expression peaked 12–24 h after exposing podocytes to high glucose. Inhibition of autophagy with 3-methyladenine or Beclin-1 siRNAs or Atg 5 siRNAs sensitized cells to apoptosis, suggesting autophagy is a survival mechanism. HO-1 inactivation inhibited autophagy, which aggravated podocyte injury in vitro. Hemin-induced autophagy also protected podocytes from hyperglycemia in vitro and was abrogated by HO-1 siRNA. Adenosine monophosphate-activated protein kinase phosphorylation was higher in hemin-treated and lower in HO-1 siRNA-treated podocytes. Suppression of AMPK activity reversed HO-1-mediated Beclin-1 upregulation and autophagy, indicating HO-1-mediated autophagy is AMPK dependent. These findings suggest HO-1 induction and regulation of autophagy are potential therapeutic targets for diabetic nephropathy. - Highlights: • High glucose leads to increased autophagy in podocytes at an early stage. • The early autophagic response protects against high glucose-induced apoptosis. • Heme oxygenase-1 enhances autophagy and decreases high glucose -mediated apoptosis. • Heme oxygenase-1 induces autophagy through the activation of AMPK.

  2. Heme oxygenase-1 enhances autophagy in podocytes as a protective mechanism against high glucose-induced apoptosis

    International Nuclear Information System (INIS)

    Injury and loss of podocytes play vital roles in diabetic nephropathy progression. Emerging evidence suggests autophagy, which is induced by multiple stressors including hyperglycemia, plays a protective role. Meanwhile, heme oxygenase-1 (HO-1) possesses powerful anti-apoptotic properties. Therefore, we investigated the impact of autophagy on podocyte apoptosis under diabetic conditions and its association with HO-1. Mouse podocytes were cultured in vitro; apoptosis was detected by flow cytometry. Transmission electron microscopy and biochemical autophagic flux assays were used to measure the autophagy markers microtubule-associated protein 1 light chain 3-II (LC3-II) and beclin-1. LC3-II and beclin-1 expression peaked 12–24 h after exposing podocytes to high glucose. Inhibition of autophagy with 3-methyladenine or Beclin-1 siRNAs or Atg 5 siRNAs sensitized cells to apoptosis, suggesting autophagy is a survival mechanism. HO-1 inactivation inhibited autophagy, which aggravated podocyte injury in vitro. Hemin-induced autophagy also protected podocytes from hyperglycemia in vitro and was abrogated by HO-1 siRNA. Adenosine monophosphate-activated protein kinase phosphorylation was higher in hemin-treated and lower in HO-1 siRNA-treated podocytes. Suppression of AMPK activity reversed HO-1-mediated Beclin-1 upregulation and autophagy, indicating HO-1-mediated autophagy is AMPK dependent. These findings suggest HO-1 induction and regulation of autophagy are potential therapeutic targets for diabetic nephropathy. - Highlights: • High glucose leads to increased autophagy in podocytes at an early stage. • The early autophagic response protects against high glucose-induced apoptosis. • Heme oxygenase-1 enhances autophagy and decreases high glucose -mediated apoptosis. • Heme oxygenase-1 induces autophagy through the activation of AMPK

  3. The role of autophagy in microbial infection and immunity

    Directory of Open Access Journals (Sweden)

    Desai M

    2015-01-01

    Full Text Available Mayura Desai,1 Rong Fang,2 Jiaren Sun11Department of Microbiology and Immunology, 2Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX, USAAbstract: The autophagy pathway represents an evolutionarily conserved cell recycling process that is activated in response to nutrient deprivation and other stress signals. Over the years, it has been linked to an array of cellular functions. Equally, a wide range of cell-intrinsic, as well as extracellular, factors have been implicated in the induction of the autophagy pathway. Microbial infections represent one such factor that can not only activate autophagy through specific mechanisms but also manipulate the response to the invading microbe's advantage. Moreover, in many cases, particularly among viruses, the pathway has been shown to be intricately involved in the replication cycle of the pathogen. Conversely, autophagy also plays a role in combating the infection process, both through direct destruction of the pathogen and as one of the key mediating factors in the host defense mechanisms of innate and adaptive immunity. Further, the pathway also plays a role in controlling the pathogenesis of infectious diseases by regulating inflammation. In this review, we discuss various interactions between pathogens and the cellular autophagic response and summarize the immunological functions of the autophagy pathway.Keywords: autophagy, xenophagy, antiviral, antibacterial

  4. Role of autophagy in prion protein-induced neurodegenerative diseases

    Institute of Scientific and Technical Information of China (English)

    Hao Yao; Deming Zhao; Sher Hayat Khan; Lifeng Yang

    2013-01-01

    Prion diseases,characterized by spongiform degeneration and the accumulation of misfolded and aggregated PrPSc in the central nervous system,are one of fatal neurodegenerative and infectious disorders of humans and animals.In earlier studies,autophagy vacuoles in neurons were frequently observed in neurodegenerative diseases such as Alzheimer's,Parkinson's,and Huntington's diseases as well as prion diseases.Autophagy is a highly conserved homeostatic process by which several cytoplasmic components (proteins or organelles) are sequestered in a doublemembrane-bound vesicle termed 'autophagosome' and degraded upon their fusion with lysosome.The pathway of intercellular self-digestion at basal physiological levels is indispensable for maintaining the healthy status of tissues and organs.In case of prion infection,increasing evidence indicates that autophagy has a crucial ability of eliminating pathological PrPSc accumulated within neurons.In contrast,autophagy dysfunction in affected neurons may contribute to the formation of spongiform changes.In this review,we summarized recent findings about the effect of mammalian autophagy in neurodegenerative disorders,particularly in prion diseases.We also summarized the therapeutic potential of some small molecules (such as lithium,rapamycin,Sirtuin 1 and resveratrol) targets to mitigate such diseases on brain function.Furthermore,we discussed the controversial role of autophagy,whether it mediates neuronal toxicity or serves a protective function in neurodegenerative disorders.

  5. CRISPR-Mediated Drug-Target Validation Reveals Selective Pharmacological Inhibition of the RNA Helicase, eIF4A

    Directory of Open Access Journals (Sweden)

    Jennifer Chu

    2016-06-01

    Full Text Available Targeting translation initiation is an emerging anti-neoplastic strategy that capitalizes on de-regulated upstream MAPK and PI3K-mTOR signaling pathways in cancers. A key regulator of translation that controls ribosome recruitment flux is eukaryotic initiation factor (eIF 4F, a hetero-trimeric complex composed of the cap binding protein eIF4E, the scaffolding protein eIF4G, and the RNA helicase eIF4A. Small molecule inhibitors targeting eIF4F display promising anti-neoplastic activity in preclinical settings. Among these are some rocaglate family members that are well tolerated in vivo, deplete eIF4F of its eIF4A helicase subunit, have shown activity as single agents in several xenograft models, and can reverse acquired resistance to MAPK and PI3K-mTOR targeted therapies. Herein, we highlight the power of using genetic complementation approaches and CRISPR/Cas9-mediated editing for drug-target validation ex vivo and in vivo, linking the anti-tumor properties of rocaglates to eIF4A inhibition.

  6. Tyrosine Kinase 2-mediated Signal Transduction in T Lymphocytes Is Blocked by Pharmacological Stabilization of Its Pseudokinase Domain.

    Science.gov (United States)

    Tokarski, John S; Zupa-Fernandez, Adriana; Tredup, Jeffrey A; Pike, Kristen; Chang, ChiehYing; Xie, Dianlin; Cheng, Lihong; Pedicord, Donna; Muckelbauer, Jodi; Johnson, Stephen R; Wu, Sophie; Edavettal, Suzanne C; Hong, Yang; Witmer, Mark R; Elkin, Lisa L; Blat, Yuval; Pitts, William J; Weinstein, David S; Burke, James R

    2015-04-24

    Inhibition of signal transduction downstream of the IL-23 receptor represents an intriguing approach to the treatment of autoimmunity. Using a chemogenomics approach marrying kinome-wide inhibitory profiles of a compound library with the cellular activity against an IL-23-stimulated transcriptional response in T lymphocytes, a class of inhibitors was identified that bind to and stabilize the pseudokinase domain of the Janus kinase tyrosine kinase 2 (Tyk2), resulting in blockade of receptor-mediated activation of the adjacent catalytic domain. These Tyk2 pseudokinase domain stabilizers were also shown to inhibit Tyk2-dependent signaling through the Type I interferon receptor but not Tyk2-independent signaling and transcriptional cellular assays, including stimulation through the receptors for IL-2 (JAK1- and JAK3-dependent) and thrombopoietin (JAK2-dependent), demonstrating the high functional selectivity of this approach. A crystal structure of the pseudokinase domain liganded with a representative example showed the compound bound to a site analogous to the ATP-binding site in catalytic kinases with features consistent with high ligand selectivity. The results support a model where the pseudokinase domain regulates activation of the catalytic domain by forming receptor-regulated inhibitory interactions. Tyk2 pseudokinase stabilizers, therefore, represent a novel approach to the design of potent and selective agents for the treatment of autoimmunity. PMID:25762719

  7. DNA damage and autophagy

    International Nuclear Information System (INIS)

    Both exogenous and endogenous agents are a threat to DNA integrity. Exogenous environmental agents such as ultraviolet (UV) and ionizing radiation, genotoxic chemicals and endogenous byproducts of metabolism including reactive oxygen species can cause alterations in DNA structure (DNA damage). Unrepaired DNA damage has been linked to a variety of human disorders including cancer and neurodegenerative disease. Thus, efficient mechanisms to detect DNA lesions, signal their presence and promote their repair have been evolved in cells. If DNA is effectively repaired, DNA damage response is inactivated and normal cell functioning resumes. In contrast, when DNA lesions cannot be removed, chronic DNA damage triggers specific cell responses such as cell death and senescence. Recently, DNA damage has been shown to induce autophagy, a cellular catabolic process that maintains a balance between synthesis, degradation, and recycling of cellular components. But the exact mechanisms by which DNA damage triggers autophagy are unclear. More importantly, the role of autophagy in the DNA damage response and cellular fate is unknown. In this review we analyze evidence that supports a role for autophagy as an integral part of the DNA damage response.

  8. Pharmacological isolation of postsynaptic currents mediated by NR2A- and NR2B-containing NMDA receptors in the anterior cingulate cortex

    Directory of Open Access Journals (Sweden)

    Cao Xiaoyan

    2007-04-01

    Full Text Available Abstract NMDA receptors (NMDARs are involved in excitatory synaptic transmission and plasticity associated with a variety of brain functions, from memory formation to chronic pain. Subunit-selective antagonists for NMDARs provide powerful tools to dissect NMDAR functions in neuronal activities. Recently developed antagonist for NR2A-containing receptors, NVP-AAM007, triggered debates on its selectivity and involvement of the NMDAR subunits in bi-directional synaptic plasticity. Here, we re-examined the pharmacological properties of NMDARs in the anterior cingulate cortex (ACC using NVP-AAM007 as well as ifenprodil, a selective antagonist for NR2B-containing NMDARs. By alternating sequence of drug application and examining different concentrations of NVP-AAM007, we found that the presence of NVP-AAM007 did not significantly affect the effect of ifenprodil on NMDAR-mediated EPSCs. These results suggest that NVP-AAM007 shows great preference for NR2A subunit and could be used as a selective antagonist for NR2A-containing NMDARs in the ACC.

  9. Pharmacological evidence for connection of nitric oxide-mediated pathways in neuroprotective mechanism of ischemic postconditioning in mice

    Directory of Open Access Journals (Sweden)

    Puja Gulati

    2014-01-01

    Full Text Available Introduction: Postconditioning (PoCo is an adaptive phenomenon whereby brief repetitive cycles of ischemia with intermittent reperfusion instituted immediately after prolonged ischemia at the onset of prolonged reperfusion elicit tissue protection. PoCo is noted to exert a protective effect in various organs like heart, liver, kidney and brain. Various triggers, mediators and end effectors are suggested to contribute to the protective effect of PoCo. However, the neuroprotective mechanism of PoCo is poorly understood. Objectives: The present study has been designed to investigate the role of nitric oxide pathway in the neuroprotective mechanism of ischemic postconditioning (iPoCo employing a mouse model of global cerebral ischemia and reperfusion-induced injury. Materials and Methods: Bilateral carotid artery occlusion (BCAO of 12 min followed by reperfusion for 24 h was employed to produce ischemia and reperfusion (I/R-induced cerebral injury in mice. Cerebral injury was assessed in the terms of cerebral infarct, memory impairment and motor in-coordination. Brain nitrite/nitrate; acetylcholinesterase activity, thiobarbituric acid reactive species (TBARS and glutathione level were also estimated. Results: BCAO followed by reperfusion produced a significant rise in cerebral infarct size, memory impairment and motor incoordination. Further a rise in acetylcholinesterase activity and TBARS level along with fall in brain nitrite/nitrate and glutathione levels was also noted. iPoCo consisting of three episodes of 10 s carotid artery occlusion and reperfusion (instituted immediately after BCAO significantly attenuated infarct size, memory impairment, motor incoordination as well as altered biochemicals. iPoCo-induced neuroprotective effects were significantly abolished by pretreatment of L-NAME, a nonselective NOS inhibitor. Conclusion: It may be concluded that the nitric oxide pathway probably plays a vital role in the neuroprotective mechanism of iPoCo.

  10. Deconvoluting the relationships between autophagy and metastasis for potential cancer therapy.

    Science.gov (United States)

    Yao, Dahong; Wang, Peiqi; Zhang, Jin; Fu, Leilei; Ouyang, Liang; Wang, Jinhui

    2016-06-01

    Autophagy is a highly conserved lysosome-dependent degradation process that may digest some long-lived proteins and damaged organelles. As an essential homeostasis maintaining system in normal cells, autophagy plays a key role in several pathological settings, especially cancer. Metastasis, known as a crucial hallmark of cancer progression, is the primary cause of cancer lethality. The role of autophagy in metastasis is quite complex as supportive evidence has indicated both pro-metastatic and anti-metastatic functions of autophagy. Autophagy can inhibit metastasis by restricting necrosis and mediating autophagic cell death, whereas it may also promote metastasis by enhancing cancer cell fitness in response to stress. Moreover, the function of autophagy is context- and stage-dependent. Specifically, during the early steps of metastasis, autophagy mainly serves as a suppressor, while it plays a pro-metastatic role in the later steps. Here, we focus on highlighting the dual roles of autophagy in metastasis and address the molecular mechanisms involved in this process, which may provide a new insight into cancer biology. While, we also summarize several anti-metastatic agents manipulating autophagy, in the hope of shedding light on exploration of potential novel drugs for future cancer therapy. PMID:27003389

  11. Autophagy studies in Bombyx mori

    Directory of Open Access Journals (Sweden)

    L Tian

    2015-03-01

    Full Text Available Autophagy, which is well conserved from yeast to mammals, plays essential roles in development and diseases. Using the domesticated silkworm, Bombyx mori, as a model insect, several reports on autophagy have been made recently. Autophagic features are observed in the midgut and fat body during the larval-pupal transition as well as the silk gland and ovarian nurse cells during the pupal stage. There are 14 autophagy related (Atg genes, including at least two transcript variants of Atg1, predicated in Bombyx. Expression of most Atg genes is consistent with the autophagy process in the fat body during the larval-pupal transition, and reduction of Atg1 expression by RNAi blocks this process. The molting hormone, 20-hydroxyecdysone (20E, and starvation induce autophagy in the fat body by upregulating Atg gene expression and blocking the PI3K-TORC1 pathway. Meanwhile, autophagy precedes apoptosis in the midgut and other larval tissues during the larval-pupal transition, while the detailed mechanism is not illustrated yet. We assume that there are at least four future directions about autophagy studies in Bombyx during the next years: (1 physiological functions of autophagy; (2 identification of new components involved in the autophagy process; (3 detailed molecular mechanism of autophagosome formation; (4 functional relationship between autophagy and apoptosis.

  12. Autophagy can be a killer even in apoptosis-competent cells.

    Science.gov (United States)

    Guillon-Munos, Audrey; van Bemmelen, Miguel X P; Clarke, Peter G H

    2006-01-01

    Despite abundant evidence for autophagic cell death as a morphological type, the notion that autophagy can actually contribute mechanistically to the cell's death is controversial. In cells capable of apoptosis, autophagic cell death has been dismissed by some authors as a morphologically unusual form of apoptosis. But strong recent evidence for autophagy-mediated death of cells rendered incapable of apoptosis has been criticized on the grounds that this cell death is too artificial to be relevant to normal cells. We here argue from our own and other recent evidence that autophagy can mediate the death even of apoptosis-competent cells. PMID:16874064

  13. Pharmacologically distinct pramipexole-mediated akinesia vs. risk-taking in a rat model of Parkinson's disease.

    Science.gov (United States)

    Holtz, Nathan A; Tedford, Stephanie E; Persons, Amanda L; Grasso, Salvatore A; Napier, T Celeste

    2016-10-01

    Pramipexole and ropinirole are dopamine agonists that are efficacious in treating motor disturbances of neuropathologies, e.g., Parkinson's disease and restless legs syndrome. A significant portion of treated patients develop impulsive/compulsive behaviors. Current treatment is dose reduction or switching to an alternative dopamine replacement, both of which can undermine the motor benefits. Needed is a preclinical model that can assist in identifying adjunct treatments to dopamine agonist therapy that reduce impulsive/compulsive behaviors without interfering with motor benefits of the dopamine agonist. Toward that objective, the current study implemented a rat model of Parkinson's disease to behaviorally profile chronically administered pramipexole. This was accomplished with male Sprague-Dawley rats wherein (i) 6-hydroxydopamine-induced lesions of the dorsolateral striatum produced Parkinson's disease-like akinesia, measured in the forelimbs, (ii) intracranial self-stimulation-mediated probability discounting indicated impulsivity/risk-taking, and (iii) two doses of pramipexole were continuously administered for 14-28days via osmotic minipumps to mirror the chronic, stable exposure achieved with extended release formulations. The atypical antidepressant, mirtazapine, is known to reduce behaviors associated with drug addiction in rats; thus, we demonstrated model utility here by determining the effects of mirtazapine on pramipexole-induced motor improvements versus probability discounting. We observed that forelimb akinesia subsequent to striatal lesions was attenuated by both pramipexole doses tested (0.3 and 1.2mg/kg/day) within 4h of pump implant dispensing 0.3mg/kg/day and 1h by 1.2mg/kg/day. By contrast, 12-14days of infusion with 0.3mg/kg/day did not alter discounting, but increases were obtained with 1.2mg/kg/day pramipexole, with 67% of 1.2mg/kg/day-treated rats meeting categorical criteria for 'high risk-taking'. Insertion of a second minipump delivering

  14. Optineurin is an autophagy receptor for damaged mitochondria in parkin-mediated mitophagy that is disrupted by an ALS-linked mutation

    OpenAIRE

    Wong, Yvette C.; Holzbaur, Erika L.F.

    2014-01-01

    In mitophagy, damaged mitochondria recruit parkin to ubiquitinate proteins on the outer mitochondrial membrane, targeting mitochondria for autophagosome engulfment and degradation. However, the proteins involved in mediating autophagosome formation to degrade damaged and ubiquitinated mitochondria remain unknown. We used live cell imaging to demonstrate that optineurin is actively recruited to parkin-labeled ubiquitinated mitochondria and is stabilized by its ubiquitin binding domain. Optineu...

  15. Autophagy During Cardiac Stress: Joys and Frustrations of Autophagy

    Science.gov (United States)

    Gottlieb, Roberta A.; Mentzer, Robert M.

    2013-01-01

    The study of autophagy has been transformed by the cloning of most genes in the pathway and the introduction of GFP-LC3 as a reporter to allow visual assessment of autophagy. The field of cardiac biology is not alone in attempting to understand the implications of autophagy. The purpose of this review is to address some of the controversies and conundrums associated with the evolving studies of autophagy in the heart. Autophagy is a cellular process involving a complex orchestration of regulatory gene products as well as machinery for assembly, selective targeting, and degradation of autophagosomes and their contents. Our understanding of the role of autophagy in human disease is rapidly evolving as investigators examine the process in different tissues and different pathophysiological contexts. In the field of heart disease, autophagy has been examined in the settings of ischemia and reperfusion, preconditioning, cardiac hypertrophy, and heart failure. This review addresses the role of autophagy in cardioprotection, the balance of catabolism and anabolism, the concept of mitochondrial quality control, and the implications of impaired autophagic flux or frustrated autophagy. PMID:20148666

  16. 5-Methoxyflavanone induces cell cycle arrest at the G2/M phase, apoptosis and autophagy in HCT116 human colon cancer cells

    International Nuclear Information System (INIS)

    Natural flavonoids have diverse pharmacological activities, including anti-oxidative, anti-inflammatory, and anti-cancer activities. In this study, we investigated the molecular mechanism underlying the action of 5-methoxyflavanone (5-MF) which has a strong bioavailability and metabolic stability. Our results show that 5-MF inhibited the growth and clonogenicity of HCT116 human colon cancer cells, and that it activated DNA damage responses, as revealed by the accumulation of p53 and the phosphorylation of DNA damage-sensitive proteins, including ataxia-telangiectasia mutated (ATM) at Ser1981, checkpoint kinase 2 (Chk2) at Thr68, and histone H2AX at Ser139. 5-MF-induced DNA damage was confirmed in a comet tail assay. We also found that 5-MF increased the cleavage of caspase-2 and -7, leading to the induction of apoptosis. Pretreatment with the ATM inhibitor KU55933 enhanced 5-MF-induced γ-H2AX formation and caspase-7 cleavage. HCT116 cells lacking p53 (p53-/-) or p21 (p21-/-) exhibited increased sensitivity to 5-MF compared to wild-type cells. 5-MF further induced autophagy via an ERK signaling pathway. Blockage of autophagy with the MEK inhibitor U0126 potentiated 5-MF-induced γ-H2AX formation and caspase-2 activation. These results suggest that a caspase-2 cascade mediates 5-MF-induced anti-tumor activity, while an ATM/Chk2/p53/p21 checkpoint pathway and ERK-mediated autophagy act as a survival program to block caspase-2-mediated apoptosis induced by 5-MF. - Graphical abstract: Display Omitted Highlights: → 5-MF inhibits the proliferation of HCT116 colon cancer cells. → 5-MF inhibits cell cycle progression and induces apoptosis. → Inhibition of autophagy triggers 5-MF-induced apoptosis. → Inhibition of ERK signaling blocks 5-MF-induced autophagy but activates apoptosis. → Treatment with 5-MF in combination with an ERK inhibitor may be a potential therapeutic strategy in human colon cancer.

  17. Autophagy in plants and phytopathogens.

    Science.gov (United States)

    Yoshimoto, Kohki; Takano, Yoshitaka; Sakai, Yasuyoshi

    2010-04-01

    Plants and plant-associated microorganisms including phytopathogens have to adapt to drastic changes in environmental conditions. Because of their immobility, plants must cope with various types of environmental stresses such as starvation, oxidative stress, drought stress, and invasion by phytopathogens during their differentiation, development, and aging processes. Here we briefly describe the early studies of plant autophagy, summarize recent studies on the molecular functions of ATG genes, and speculate on the role of autophagy in plants and phytopathogens. Autophagy regulates senescence and pathogen-induced cell death in plants, and autophagy and pexophagy play critical roles in differentiation and the invasion of host cells by phytopathogenic fungi. PMID:20079356

  18. Autophagy extends lifespan via vacuolar acidification

    Directory of Open Access Journals (Sweden)

    Christoph Ruckenstuhl

    2014-05-01

    Full Text Available Methionine restriction (MetR is one of the rare regimes that prolongs lifespan across species barriers. Using a yeast model, we recently demonstrated that this lifespan extension is promoted by autophagy, which in turn requires vacuolar acidification. Our study is the first to place autophagy as one of the major players required for MetR-mediated longevity. In addition, our work identifies vacuolar acidification as a key downstream element of autophagy induction under MetR, and possibly after rapamycin treatment. Unlike other amino acids, methionine plays pleiotropic roles in many metabolism-relevant pathways. For instance, methionine (i is the N-terminal amino acid of every newly translated protein; (ii acts as the central donor of methyl groups through S-adenosyl methionine (SAM during methylation reactions of proteins, DNA or RNA; and (iii provides the sulfhydryl groups for FeS-cluster formation and redox detoxification via transsulfuration to cysteine. Intriguingly, MetR causes lifespan extension, both in yeast and in rodents. We could show that in Saccharomyces cerevisiae, chronological lifespan (CLS is increased in two specific methionine-auxotrophic strains (namely Δmet2 and Δmet15.

  19. Spermidine induces autophagy by inhibiting the acetyltransferase EP300.

    Science.gov (United States)

    Pietrocola, F; Lachkar, S; Enot, D P; Niso-Santano, M; Bravo-San Pedro, J M; Sica, V; Izzo, V; Maiuri, M C; Madeo, F; Mariño, G; Kroemer, G

    2015-03-01

    Several natural compounds found in health-related food items can inhibit acetyltransferases as they induce autophagy. Here we show that this applies to anacardic acid, curcumin, garcinol and spermidine, all of which reduce the acetylation level of cultured human cells as they induce signs of increased autophagic flux (such as the formation of green fluorescent protein-microtubule-associated protein 1A/1B-light chain 3 (GFP-LC3) puncta and the depletion of sequestosome-1, p62/SQSTM1) coupled to the inhibition of the mammalian target of rapamycin complex 1 (mTORC1). We performed a screen to identify the acetyltransferases whose depletion would activate autophagy and simultaneously inhibit mTORC1. The knockdown of only two acetyltransferases (among 43 candidates) had such effects: EP300 (E1A-binding protein p300), which is a lysine acetyltranferase, and NAA20 (N(α)-acetyltransferase 20, also known as NAT5), which catalyzes the N-terminal acetylation of methionine residues. Subsequent studies validated the capacity of a pharmacological EP300 inhibitor, C646, to induce autophagy in both normal and enucleated cells (cytoplasts), underscoring the capacity of EP300 to repress autophagy by cytoplasmic (non-nuclear) effects. Notably, anacardic acid, curcumin, garcinol and spermidine all inhibited the acetyltransferase activity of recombinant EP300 protein in vitro. Altogether, these results support the idea that EP300 acts as an endogenous repressor of autophagy and that potent autophagy inducers including spermidine de facto act as EP300 inhibitors. PMID:25526088

  20. Mycobacterium tuberculosis induces the miR-33 locus to reprogram autophagy and host lipid metabolism.

    Science.gov (United States)

    Ouimet, Mireille; Koster, Stefan; Sakowski, Erik; Ramkhelawon, Bhama; van Solingen, Coen; Oldebeken, Scott; Karunakaran, Denuja; Portal-Celhay, Cynthia; Sheedy, Frederick J; Ray, Tathagat Dutta; Cecchini, Katharine; Zamore, Philip D; Rayner, Katey J; Marcel, Yves L; Philips, Jennifer A; Moore, Kathryn J

    2016-06-01

    Mycobacterium tuberculosis (Mtb) survives in macrophages by evading delivery to the lysosome and promoting the accumulation of lipid bodies, which serve as a bacterial source of nutrients. We found that by inducing the microRNA (miRNA) miR-33 and its passenger strand miR-33*, Mtb inhibited integrated pathways involved in autophagy, lysosomal function and fatty acid oxidation to support bacterial replication. Silencing of miR-33 and miR-33* by genetic or pharmacological means promoted autophagy flux through derepression of key autophagy effectors (such as ATG5, ATG12, LC3B and LAMP1) and AMPK-dependent activation of the transcription factors FOXO3 and TFEB, which enhanced lipid catabolism and Mtb xenophagy. These data define a mammalian miRNA circuit used by Mtb to coordinately inhibit autophagy and reprogram host lipid metabolism to enable intracellular survival and persistence in the host. PMID:27089382

  1. Transcription factors and cognate signalling cascades in the regulation of autophagy.

    Science.gov (United States)

    Chandra, Vemika; Bhagyaraj, Ella; Parkesh, Raman; Gupta, Pawan

    2016-05-01

    Autophagy is a process that maintains the equilibrium between biosynthesis and the recycling of cellular constituents; it is critical for avoiding the pathophysiology that results from imbalance in cellular homeostasis. Recent reports indicate the need for the design of high-throughput screening assays to identify targets and small molecules for autophagy modulation. For such screening, however, a better understanding of the regulation of autophagy is essential. In addition to regulation by various signalling cascades, regulation of gene expression by transcription factors is also critical. This review focuses on the various transcription factors as well as the corresponding signalling molecules that act together to translate the stimuli to effector molecules that up- or downregulate autophagy. This review rationalizes the importance of these transcription factors functioning in tandem with cognate signalling molecules and their interfaces as possible therapeutic targets for more specific pharmacological interventions. PMID:25651938

  2. Pharmacological Evidence that Histamine H3 Receptors Mediate Histamine-Induced Inhibition of the Vagal Bradycardic Out-flow in Pithed Rats.

    Science.gov (United States)

    García, Mónica; García-Pedraza, José Ángel; Villalón, Carlos M; Morán, Asunción

    2016-02-01

    In vivo stimulation of cardiac vagal neurons induces bradycardia by acetylcholine (ACh) release. As vagal release of ACh may be modulated by autoreceptors (muscarinic M2 ) and heteroreceptors (including serotonin 5-HT1 ), this study has analysed the pharmacological profile of the receptors involved in histamine-induced inhibition of the vagal bradycardic out-flow in pithed rats. For this purpose, 180 male Wistar rats were pithed, artificially ventilated and pre-treated (i.v.) with 1 mg/kg atenolol, followed by i.v. administration of physiological saline (1 ml/kg), histamine (10, 50, 100 and 200 μg/kg) or the selective histamine H1 (2-pyridylethylamine), H2 (dimaprit), H3 (methimepip) and H4 (VUF 8430) receptor agonists (1, 10, 50 and 100 μg/kg each). Under these conditions, electrical stimulation (3, 6 and 9 Hz; 15 ± 3 V and 1 ms) of the vagus nerve resulted in frequency-dependent bradycardic responses, which were (i) unchanged during the infusions of saline, 2-pyridylethylamine, dimaprit or VUF 8430; and (ii) dose-dependently inhibited by histamine or methimepip. Moreover, the inhibition of the bradycardia caused by 50 μg/kg of either histamine or methimepip (which failed to inhibit the bradycardic responses to i.v. bolus injections of acetylcholine; 1-10 μg/kg) was abolished by the H3 receptor antagonist JNJ 10181457 (1 mg/kg, i.v.). In conclusion, our results suggest that histamine-induced inhibition of the vagal bradycardic out-flow in pithed rats is mainly mediated by pre-junctional activation of histamine H3 receptors, as previously demonstrated for the vasopressor sympathetic out-flow and the vasodepressor sensory CGRPergic (calcitonin gene-related peptide) out-flow. PMID:26301462

  3. PUMA and Bax-induced Autophagy Contributes to Apoptosis

    OpenAIRE

    Yee, Karen S.; Wilkinson, Simon; James, John; Ryan, Kevin M.; Vousden, Karen H.

    2009-01-01

    The p53-inducible BH3-only protein PUMA is a key mediator of p53-dependent apoptosis, and PUMA has been shown to function by activating Bax and mitochondrial outer membrane permeabilization. In this study we describe an ability of PUMA to induce autophagy that leads to the selective removal of mitochondria. This function of PUMA depends on Bax/Bak and can be reproduced by overexpression of Bax. The induction of autophagy coincides with cytochrome c release, and taken together the results sugg...

  4. PUMA- and Bax-induced autophagy contributes to apoptosis

    OpenAIRE

    Yee, K S; Wilkinson, S; James, J; Ryan, K M; Vousden, K H

    2009-01-01

    The p53-inducible BH3-only protein PUMA is a key mediator of p53-dependent apoptosis, and PUMA has been shown to function by activating Bax and mitochondrial outer membrane permeabilization. In this study, we describe an ability of PUMA to induce autophagy that leads to the selective removal of mitochondria. This function of PUMA depends on Bax/Bak and can be reproduced by overexpression of Bax. The induction of autophagy coincides with cytochrome c release, and taken together the results sug...

  5. Bim Inhibits Autophagy by Recruiting Beclin 1 to Microtubules

    OpenAIRE

    Luo, Shouqing; Garcia-Arencibia, Moises; Zhao, Rui; Puri, Claudia; Toh, Pearl P.C.; Sadiq, Oana; Rubinsztein, David C.

    2012-01-01

    Summary Bim is a proapoptotic BH3-only Bcl-2 family member. In response to death stimuli, Bim dissociates from the dynein light chain 1 (DYNLL1/LC8), where it is inactive, and can then initiate Bax/Bak-mediated mitochondria-dependent apoptosis. We found that Bim depletion increases autophagosome synthesis in cells and in vivo, and this effect is inhibited by overexpression of cell death-deficient Bim. Bim inhibits autophagy by interacting with Beclin 1, an autophagy regulator, and this intera...

  6. Autophagy in cardiovascular biology

    OpenAIRE

    Lavandero, Sergio; Chiong, Mario; Rothermel, Beverly A.; Hill, Joseph A.

    2015-01-01

    Cardiovascular disease is the leading cause of death worldwide. As such, there is great interest in identifying novel mechanisms that govern the cardiovascular response to disease-related stress. First described in failing hearts, autophagy within the cardiovascular system has been widely characterized in cardiomyocytes, cardiac fibroblasts, endothelial cells, vascular smooth muscle cells, and macrophages. In all cases, a window of optimal autophagic activity appears to be critical to the mai...

  7. AUTOPHAGY IN LUNG CANCER

    OpenAIRE

    Jaboin, Jerry J.; Hwang, Misun; Lu, Bo

    2009-01-01

    Lung cancer is the leading cause of cancer-related deaths worldwide. The relatively poor cure rate in lung cancer patients has been associated with a resistance to chemotherapy and radiation that is at least in part related to defects in cellular apoptotic machinery. Exploitation of another form of cell death, autophagy, has the capacity to improve the therapeutic gain of current therapies. In an effort to develop novel treatment strategies to enhance the therapeutic ratio for lung cancer, we...

  8. Autophagy in dementias.

    Science.gov (United States)

    Kragh, Christine Lund; Ubhi, Kiren; Wyss-Coray, Tony; Wyss-Corey, Tony; Masliah, Eliezer

    2012-01-01

    Dementias are a varied group of disorders typically associated with memory loss, impaired judgment and/or language and by symptoms affecting other cognitive and social abilities to a degree that interferes with daily functioning. Alzheimer's disease (AD) is the most common cause of a progressive dementia, followed by dementia with Lewy bodies (DLB), frontotemporal dementia (FTD), (VaD) and HIV-associated neurocognitive disorders (HAND). The pathogenesis of this group of disorders has been linked to the abnormal accumulation of proteins in the brains of affected individuals, which in turn has been related to deficits in protein clearance. Autophagy is a key cellular protein clearance pathway with proteolytic cleavage and degradation via the ubiquitin-proteasome pathway representing another important clearance mechanism. Alterations in the levels of autophagy and the proteins associated with the autophagocytic pathway have been reported in various types of dementias. This review will examine recent literature across these disorders and highlight a common theme of altered autophagy across the spectrum of the dementias. PMID:22150925

  9. Sinomenine Hydrochloride Protects against Polymicrobial Sepsis via Autophagy

    Directory of Open Access Journals (Sweden)

    Yu Jiang

    2015-01-01

    Full Text Available Sepsis, a systemic inflammatory response to infection, is the major cause of death in intensive care units (ICUs. The mortality rate of sepsis remains high even though the treatment and understanding of sepsis both continue to improve. Sinomenine (SIN is a natural alkaloid extracted from Chinese medicinal plant Sinomenium acutum, and its hydrochloride salt (Sinomenine hydrochloride, SIN-HCl is widely used to treat rheumatoid arthritis (RA. However, its role in sepsis remains unclear. In the present study, we investigated the role of SIN-HCl in sepsis induced by cecal ligation and puncture (CLP in BALB/c mice and the corresponding mechanism. SIN-HCl treatment improved the survival of BALB/c mice that were subjected to CLP and reduced multiple organ dysfunction and the release of systemic inflammatory mediators. Autophagy activities were examined using Western blotting. The results showed that CLP-induced autophagy was elevated, and SIN-HCl treatment further strengthened the autophagy activity. Autophagy blocker 3-methyladenine (3-MA was used to investigate the mechanism of SIN-HCl in vitro. Autophagy activities were determined by examining the autophagosome formation, which was shown as microtubule-associated protein light chain 3 (LC3 puncta with green immunofluorescence. SIN-HCl reduced lipopolysaccharide (LPS-induced inflammatory cytokine release and increased autophagy in peritoneal macrophages (PM. 3-MA significantly decreased autophagosome formation induced by LPS and SIN-HCl. The decrease of inflammatory cytokines caused by SIN-HCl was partially aggravated by 3-MA treatment. Taken together, our results indicated that SIN-HCl could improve survival, reduce organ damage, and attenuate the release of inflammatory cytokines induced by CLP, at least in part through regulating autophagy activities.

  10. Autophagy plays an essential role in cigarette smoke-induced expression of MUC5AC in airway epithelium.

    Science.gov (United States)

    Zhou, Jie-Sen; Zhao, Yun; Zhou, Hong-Bin; Wang, Yong; Wu, Yin-Fang; Li, Zhou-Yang; Xuan, Nan-Xia; Zhang, Chao; Hua, Wen; Ying, Song-Min; Li, Wen; Shen, Hua-Hao; Chen, Zhi-Hua

    2016-06-01

    Mucus hypersecretion is a common pathological feature of chronic airway inflammatory diseases including chronic obstructive pulmonary disease (COPD). However, the molecular basis for this condition remains incompletely understood. We have previously demonstrated a critical role of autophagy in COPD pathogenesis through mediating apoptosis of lung epithelial cells. In this study, we aimed to investigate the function of autophagy as well as its upstream and downstream signals in cigarette smoke-induced mucus production in human bronchial epithelial (HBE) cells and in mouse airways. Cigarette smoke extract (CSE), as well as the classical autophagy inducers starvation or Torin-1, significantly triggered MUC5AC expression, and inhibition of autophagy markedly attenuated CSE-induced mucus production. The CSE-induced autophagy was mediated by mitochondrial reactive oxygen species (mitoROS), which regulated mucin expression through the JNK and activator protein-1 pathway. Epidermal growth factor receptor (EGFR) was also required for CSE-induced MUC5AC in HBE cells, but it exerted inconsiderable effects on the autophagy-JNK signaling cascade. Airways of mice with dysfunctional autophagy-related genes displayed a markedly reduced number of goblet cells and attenuated levels of Muc5ac in response to cigarette smoke exposure. These results altogether suggest that mitoROS-dependent autophagy is essential for cigarette smoke-induced mucus hyperproduction in airway epithelial cells, and reemphasize autophagy inhibition as a novel therapeutic strategy for chronic airway diseases. PMID:27036871

  11. Regulation of Autophagy by Kinases

    International Nuclear Information System (INIS)

    Autophagy is a process of self-degradation that maintains cellular viability during periods of metabolic stress. Although autophagy is considered a survival mechanism when faced with cellular stress, extensive autophagy can also lead to cell death. Aberrations in autophagy are associated with several diseases, including cancer. Therapeutic exploitation of this process requires a clear understanding of its regulation. Although the core molecular components involved in the execution of autophagy are well studied there is limited information on how cellular signaling pathways, particularly kinases, regulate this complex process. Protein kinases are integral to the autophagy process. Atg1, the first autophagy-related protein identified, is a serine/threonine kinase and it is regulated by another serine/threonine kinase mTOR. Emerging studies suggest the participation of many different kinases in regulating various components/steps of this catabolic process. This review focuses on the regulation of autophagy by several kinases with particular emphasis on serine/threonine protein kinases such as mTOR, AMP-activated protein kinase, Akt, mitogen-activated protein kinase (ERK, p38 and JNK) and protein kinase C that are often deregulated in cancer and are important therapeutic targets

  12. You are what you eat: multifaceted functions of autophagy during C. elegans development.

    Science.gov (United States)

    Yang, Peiguo; Zhang, Hong

    2014-01-01

    Autophagy involves the sequestration of a portion of the cytosolic contents in an enclosed double-membrane autophagosomal structure and its subsequent delivery to lysosomes for degradation. Autophagy activity functions in multiple biological processes during Caenorhabditis elegans development. The basal level of autophagy in embryos removes aggregate-prone proteins, paternal mitochondria and spermatid-specific membranous organelles (MOs). Autophagy also contributes to the efficient removal of embryonic apoptotic cell corpses by promoting phagosome maturation. During larval development, autophagy modulates miRNA-mediated gene silencing by selectively degrading AIN-1, a component of miRNA-induced silencing complex, and thus participates in the specification of multiple cell fates controlled by miRNAs. During development of the hermaphrodite germline, autophagy acts coordinately with the core apoptotic machinery to execute genotoxic stress-induced germline cell death and also cell death when caspase activity is partially compromised. Autophagy is also involved in the utilization of lipid droplets in the aging process in adult animals. Studies in C. elegans provide valuable insights into the physiological functions of autophagy in the development of multicellular organisms. PMID:24296782

  13. Structure biology of selective autophagy receptors

    Science.gov (United States)

    Kim, Byeong-Won; Kwon, Do Hoon; Song, Hyun Kyu

    2016-01-01

    Autophagy is a process tightly regulated by various autophagy-related proteins. It is generally classified into non-selective and selective autophagy. Whereas non-selective autophagy is triggered when the cell is under starvation, selective autophagy is involved in eliminating dysfunctional organelles, misfolded and/or ubiquitylated proteins, and intracellular pathogens. These components are recognized by autophagy receptors and delivered to phagophores. Several selective autophagy receptors have been identified and characterized. They usually have some common domains, such as motif, a specific cargo interacting (ubiquitin-dependent or ubiquitin-independent) domain. Recently, structural data of these autophagy receptors has been described, which provides an insight of their function in the selective autophagic process. In this review, we summarize the most up-to-date findings about the structure-function of autophagy receptors that regulates selective autophagy. [BMB Reports 2016; 49(2): 73-80] PMID:26698872

  14. Activation of antibacterial autophagy by NADPH oxidases

    OpenAIRE

    Huang, Ju; Canadien, Veronica; Lam, Grace Y.; Steinberg, Benjamin E.; Mary C. Dinauer; Magalhaes, Marco A. O.; Glogauer, Michael; Grinstein, Sergio; Brumell, John H.

    2009-01-01

    Autophagy plays an important role in immunity to microbial pathogens. The autophagy system can target bacteria in phagosomes, promoting phagosome maturation and preventing pathogen escape into the cytosol. Recently, Toll-like receptor (TLR) signaling from phagosomes was found to initiate their targeting by the autophagy system, but the mechanism by which TLR signaling activates autophagy is unclear. Here we show that autophagy targeting of phagosomes is not exclusive to those containing TLR l...

  15. Exploiting cannabinoid-induced cytotoxic autophagy to drive melanoma cell death.

    Science.gov (United States)

    Armstrong, Jane L; Hill, David S; McKee, Christopher S; Hernandez-Tiedra, Sonia; Lorente, Mar; Lopez-Valero, Israel; Eleni Anagnostou, Maria; Babatunde, Fiyinfoluwa; Corazzari, Marco; Redfern, Christopher P F; Velasco, Guillermo; Lovat, Penny E

    2015-06-01

    Although the global incidence of cutaneous melanoma is increasing, survival rates for patients with metastatic disease remain Sativex-like (a laboratory preparation comprising equal amounts of THC and cannabidiol (CBD)) to mice bearing BRAF wild-type melanoma xenografts substantially inhibited melanoma viability, proliferation, and tumor growth paralleled by an increase in autophagy and apoptosis compared with standard single-agent temozolomide. Collectively, our findings suggest that THC activates noncanonical autophagy-mediated apoptosis of melanoma cells, suggesting that cytotoxic autophagy induction with Sativex warrants clinical evaluation for metastatic disease. PMID:25674907

  16. Ribose 5-phosphate isomerase inhibits LC3 processing and basal autophagy.

    Science.gov (United States)

    Heintze, Jacob; Costa, Joana R; Weber, Melanie; Ketteler, Robin

    2016-09-01

    Autophagy and cellular metabolism are tightly linked processes, but how individual metabolic enzymes regulate the process of autophagy is not well understood. This study implicates ribose-5-phosphate isomerase (RPIA), a key regulator of the pentose phosphate pathway, in the control of autophagy. We used a dual gene deletion strategy, combining shRNA-mediated knockdown studies with CRISPR/Cas9 genome editing. Knockdown of RPIA by shRNA or genomic deletion by CRISPR/Cas9 genome editing, results in an increase of ATG4B-mediated LC3 processing and in the appearance of LC3-positive autophagosomes in cells. Increased LC3 processing upon knockdown of RPIA can be reversed by treatment with the antioxidant N-acetyl cysteine. The results are consistent with a model in which RPIA suppresses autophagy and LC3 processing by modulation of redox signaling. PMID:27328773

  17. Autophagy and neurodegenerative disorders

    Institute of Scientific and Technical Information of China (English)

    Evangelia Kesidou; Roza Lagoudaki; Olga Touloumi; Kyriaki-Nefeli Poulatsidou; Constantina Simeonidou

    2013-01-01

    Accumulation of aberrant proteins and inclusion bodies are hallmarks in most neurodegenerative diseases. Consequently, these aggregates within neurons lead to toxic effects, overproduction of reactive oxygen species and oxidative stress. Autophagy is a significant intracel ular mechanism that removes damaged organelles and misfolded proteins in order to maintain cel homeostasis. Excessive or insufficient autophagic activity in neurons leads to altered homeostasis and influences their survival rate, causing neurodegeneration. The review article provides an update of the role of autophagic process in representative chronic and acute neurodegenerative disorders.

  18. Melatonin Protects N2a against Ischemia/Reperfusion Injury through Autophagy Enhancement

    Institute of Scientific and Technical Information of China (English)

    国艳春; 王剑飞; 王忠强; 杨易; 王西明; 段秋红

    2010-01-01

    Researches have shown that melatonin is neuroprotectant in ischemia/reperfusion-mediated injury.Although melatonin is known as an effective antioxidant,the mechanism of the protection cannot be explained merely by antioxidation.This study was devoted to explore other existing mechanisms by investigating whether melatonin protects ischemia/reperfusion-injured neurons through elevating autophagy,since autophagy has been frequently suggested to play a crucial role in neuron survival.To find it out,an ischemia/...

  19. Autophagy blockade sensitizes the anticancer activity of CA-4 via JNK-Bcl-2 pathway

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yangling; Luo, Peihua; Wang, Jincheng; Dai, Jiabin; Yang, Xiaochun; Wu, Honghai; Yang, Bo, E-mail: yang924@zju.edu.cn; He, Qiaojun, E-mail: qiaojunhe@zju.edu.cn

    2014-01-15

    Combretastatin A-4 (CA-4) has already entered clinical trials of solid tumors over ten years. However, the limited anticancer activity and dose-dependent toxicity restrict its clinical application. Here, we offered convincing evidence that CA-4 induced autophagy in various cancer cells, which was demonstrated by acridine orange staining of intracellular acidic vesicles, the degradation of p62, the conversion of LC3-I to LC3-II and GFP-LC3 punctate fluorescence. Interestingly, CA-4-mediated apoptotic cell death was further potentiated by pretreatment with autophagy inhibitors (3-methyladenine and bafilomycin A1) or small interfering RNAs against the autophagic genes (Atg5 and Beclin 1). The enhanced anticancer activity of CA-4 and 3-MA was further confirmed in the SGC-7901 xenograft tumor model. These findings suggested that CA-4-elicited autophagic response played a protective role that impeded the eventual cell death while autophagy inhibition was expected to improve chemotherapeutic efficacy of CA-4. Meanwhile, CA-4 treatment led to phosphorylation/activation of JNK and JNK-dependent phosphorylation of Bcl-2. Importantly, JNK inhibitor or JNK siRNA inhibited autophagy but promoted CA-4-induced apoptosis, indicating a key requirement of JNK-Bcl-2 pathway in the activation of autophagy by CA-4. We also identified that pretreatment of Bcl-2 inhibitor (ABT-737) could significantly enhance anticancer activity of CA-4 due to inhibition of autophagy. Taken together, our data suggested that the JNK-Bcl-2 pathway was considered as the critical regulator of CA-4-induced protective autophagy and a potential drug target for chemotherapeutic combination. - Highlights: • Autophagy inhibition could be a potential for combretastatin A-4 antitumor efficacy. • The JNK-Bcl-2 pathway plays a critical role in CA-4-induced autophagy. • ABT-737 enhances CA-4 anticancer activity due to inhibition of autophagy.

  20. Autophagy blockade sensitizes the anticancer activity of CA-4 via JNK-Bcl-2 pathway

    International Nuclear Information System (INIS)

    Combretastatin A-4 (CA-4) has already entered clinical trials of solid tumors over ten years. However, the limited anticancer activity and dose-dependent toxicity restrict its clinical application. Here, we offered convincing evidence that CA-4 induced autophagy in various cancer cells, which was demonstrated by acridine orange staining of intracellular acidic vesicles, the degradation of p62, the conversion of LC3-I to LC3-II and GFP-LC3 punctate fluorescence. Interestingly, CA-4-mediated apoptotic cell death was further potentiated by pretreatment with autophagy inhibitors (3-methyladenine and bafilomycin A1) or small interfering RNAs against the autophagic genes (Atg5 and Beclin 1). The enhanced anticancer activity of CA-4 and 3-MA was further confirmed in the SGC-7901 xenograft tumor model. These findings suggested that CA-4-elicited autophagic response played a protective role that impeded the eventual cell death while autophagy inhibition was expected to improve chemotherapeutic efficacy of CA-4. Meanwhile, CA-4 treatment led to phosphorylation/activation of JNK and JNK-dependent phosphorylation of Bcl-2. Importantly, JNK inhibitor or JNK siRNA inhibited autophagy but promoted CA-4-induced apoptosis, indicating a key requirement of JNK-Bcl-2 pathway in the activation of autophagy by CA-4. We also identified that pretreatment of Bcl-2 inhibitor (ABT-737) could significantly enhance anticancer activity of CA-4 due to inhibition of autophagy. Taken together, our data suggested that the JNK-Bcl-2 pathway was considered as the critical regulator of CA-4-induced protective autophagy and a potential drug target for chemotherapeutic combination. - Highlights: • Autophagy inhibition could be a potential for combretastatin A-4 antitumor efficacy. • The JNK-Bcl-2 pathway plays a critical role in CA-4-induced autophagy. • ABT-737 enhances CA-4 anticancer activity due to inhibition of autophagy

  1. Autophagy is not required to sustain exercise and PRKAA1/AMPK activity but is important to prevent mitochondrial damage during physical activity

    OpenAIRE

    Lo Verso, Francesca; Carnio, Silvia; Vainshtein, Anna; Sandri, Marco

    2014-01-01

    Physical activity has been recently documented to play a fundamental physiological role in the regulation of autophagy in several tissues. It has also been reported that autophagy is required for exercise itself and for training-induced adaptations in glucose homeostasis. These autophagy-mediated metabolic improvements are thought to be largely dependent on the activation of the metabolic sensor PRKAA1/AMPK. However, it is unknown whether these important benefits stem from systemic adaptation...

  2. A SIRT3/AMPK/autophagy network orchestrates the protective effects of trans-resveratrol in stressed peritoneal macrophages and RAW 264.7 macrophages.

    Science.gov (United States)

    Duan, Wen-Jun; Li, Yi-Fang; Liu, Fang-Lan; Deng, Jie; Wu, Yan-Ping; Yuan, Wei-Lin; Tsoi, Bun; Chen, Jun-Li; Wang, Qi; Cai, Shao-Hui; Kurihara, Hiroshi; He, Rong-Rong

    2016-06-01

    Resveratrol gains a great interest for its strong antioxidant properties, while the molecular mechanisms underlie the beneficial effects on psychosocial stress remain controversial. In this study, we demonstrated that resveratrol protected peritoneal macrophages and RAW 264.7 cells from stress-induced decrease in the total cell count, phagocytic capability, reactive oxygen species generation, monodansylcadaverine and mitochondrial membrane potential in stressed mice. Resveratrol promoted stress-induced autophagy in both models. Modulation of autophagy by rapamycin or 3-methyladenine regulated the protective effect of resveratrol, suggesting a role of autophagy in the protective mechanisms of resveratrol. The comparison studies revealed that distinct mechanisms were implicated in the protective effect of resveratrol and other antioxidants (vitamin C and edaravone). Resveratrol promoted autophagy via upregulating SIRT3 expression and phosphorylation of AMP-activated protein kinase (AMPK). Knockdown of SIRT3 resulted in decreased autophagy and abolished protective effect of resveratrol. SIRT1 was also involved in the protective mechanism of resveratrol, although its effect on autophagy was unnoticeable. Pharmacological manipulation of autophagy modulated the effects of resveratrol on SIRT3 and AMPK, revealing the engagement of a positive feedback loop. In sharp contrast, vitamin C and edaravone effectively protected macrophages from stress-induced cytotoxicity, accompanied by downregulated SIRT3 expression and AMPK phosphorylation, and decreased level of autophagy response. Taken together, we conclude that a SIRT3/AMPK/autophagy network orchestrates in the protective effect of resveratrol in macrophages. PMID:27021965

  3. Neuronal Autophagy and Neurodevelopmental Disorders

    OpenAIRE

    Lee, Kyung-Min; Hwang, Su-Kyung; Lee, Jin-A

    2013-01-01

    Neurodevelopmental disorders include a wide range of diseases such as autism spectrum disorders and mental retardation. Mutations in several genes that regulate neural development and synapse function have been identified in neurodevelopmental disorders. Interestingly, some affected genes and pathways in these diseases are associated with the autophagy pathway. Autophagy is a complex, bulky degradative process that involves the sequestration of cellular proteins, RNA, lipids, and cellular org...

  4. Lysosomes and autophagy in aquatic animals.

    Science.gov (United States)

    Moore, Michael N; Kohler, Angela; Lowe, David; Viarengo, Aldo

    2008-01-01

    The lysosomal-autophagic system appears to be a common target for many environmental pollutants, as lysosomes accumulate many toxic metals and organic xenobiotics, which perturb normal function and damage the lysosomal membrane. In fact, autophagic reactions frequently involving reduced lysosomal membrane integrity or stability appear to be effective generic indicators of cellular well-being in eukaryotes: in social amoebae (slime mold), mollusks and fish, autophagy/membrane destabilization is correlated with many stress and toxicological responses and pathological reactions. Prognostic use of adverse lysosomal and autophagic reactions to environmental pollutants can be used for predicting cellular dysfunction and health in aquatic animals, such as shellfish and fish, which are extensively used as sensitive bioindicators in monitoring ecosystem health; and also represent a significant food resource for at least 20% of the global human population. Explanatory frameworks for prediction of pollutant impact on health have been derived encompassing a conceptual mechanistic model linking lysosomal damage and autophagic dysfunction with injury to cells and tissues. Methods are described for tracking in vivo autophagy of fluorescently labeled cytoplasmic proteins, measuring degradation of radiolabeled intracellular proteins and morphometric measurement of lysosomal/cytoplasmic volume ratio. Additional methods for the determination of lysosomal membrane stability in lower animals are also described, which can be applied to frozen tissue sections, protozoans and isolated cells in vivo. Experimental and simulated results have also indicated that nutritional deprivation (analogous in marine mussels to caloric restriction)-induced autophagy has a protective function against toxic effects mediated by reactive oxygen species (ROS). Finally, coupled measurement of lysosomal-autophagic reactions and simulation modelling is proposed as a practical toolbox for predicting toxic

  5. Involvement of autophagy upregulation in 3,4-methylenedioxymethamphetamine ('ecstasy')-induced serotonergic neurotoxicity.

    Science.gov (United States)

    Li, I-Hsun; Ma, Kuo-Hsing; Kao, Tzu-Jen; Lin, Yang-Yi; Weng, Shao-Ju; Yen, Ting-Yin; Chen, Lih-Chi; Huang, Yuahn-Sieh

    2016-01-01

    It has been suggested that autophagy plays pathogenetic roles in cerebral ischemia, brain trauma, and neurodegenerative disorders. 3,4-Methylenedioxymethamphetamine (MDMA or ecstasy) is an illicit drug that causes long-term serotonergic neurotoxicity in the brain. Apoptosis and necrosis have been implicated in MDMA-induced neurotoxicity, but the role of autophagy in MDMA-elicited serotonergic toxicity has not been investigated. The present study aimed to examine the contribution of autophagy to neurotoxicity in serotonergic neurons in in vitro and in vivo animal models challenged with MDMA. Here, we demonstrated that in cultured rat serotonergic neurons, MDMA exposure induced LC3B-densely stained autophagosome formation, accompanying by a decrease in neurite outgrowth. Autophagy inhibitor 3-methyladenine (3-MA) significantly attenuated MDMA-induced autophagosome accumulation, and ameliorated MDMA-triggered serotonergic neurite damage and neuron death. In contrast, enhanced autophagy flux by rapamycin or impaired autophagosome clearance by bafilomycin A1 led to more autophagosome accumulation in serotonergic neurons and aggravated neurite degeneration. In addition, MDMA-induced autophagy activation in cultured serotonergic neurons might be mediated by serotonin transporter (SERT). In an in vivo animal model administered MDMA, neuroimaging showed that 3-MA protected the serotonin system against MDMA-induced downregulation of SERT evaluated by animal-PET with 4-[(18)F]-ADAM, a SERT radioligand. Taken together, our results demonstrated that MDMA triggers upregulation of autophagy in serotonergic neurons, which appears to be detrimental to neuronal growth. PMID:26610922

  6. Differential use of autophagy by primary dendritic cells specialized in cross-presentation.

    Science.gov (United States)

    Mintern, Justine D; Macri, Christophe; Chin, Wei Jin; Panozza, Scott E; Segura, Elodie; Patterson, Natalie L; Zeller, Peter; Bourges, Dorothee; Bedoui, Sammy; McMillan, Paul J; Idris, Adi; Nowell, Cameron J; Brown, Andrew; Radford, Kristen J; Johnston, Angus Pr; Villadangos, Jose A

    2015-01-01

    Antigen-presenting cells survey their environment and present captured antigens bound to major histocompatibility complex (MHC) molecules. Formation of MHC-antigen complexes occurs in specialized compartments where multiple protein trafficking routes, still incompletely understood, converge. Autophagy is a route that enables the presentation of cytosolic antigen by MHC class II molecules. Some reports also implicate autophagy in the presentation of extracellular, endocytosed antigen by MHC class I molecules, a pathway termed "cross-presentation." The role of autophagy in cross-presentation is controversial. This may be due to studies using different types of antigen presenting cells for which the use of autophagy is not well defined. Here we report that active use of autophagy is evident only in DC subtypes specialized in cross-presentation. However, the contribution of autophagy to cross-presentation varied depending on the form of antigen: it was negligible in the case of cell-associated antigen or antigen delivered via receptor-mediated endocytosis, but more prominent when the antigen was a soluble protein. These findings highlight the differential use of autophagy and its machinery by primary cells equipped with specific immune function, and prompt careful reassessment of the participation of this endocytic pathway in antigen cross-presentation. PMID:25950899

  7. Autophagy inhibition facilitates erlotinib cytotoxicity in lung cancer cells through modulation of endoplasmic reticulum stress.

    Science.gov (United States)

    Wang, Zhongliang; Du, Tingting; Dong, Xiaorong; Li, Zhenyu; Wu, Gang; Zhang, Ruiguang

    2016-06-01

    Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have revolutionized the treatment for non-small cell lung cancer patients, but acquired resistance limit the efficiency of this treatment. As a homeostatic cellular recycling mechanism, autophagy has been proposed to participate in the EGFR-TKI resistance. However, the role of autophagy in lung cancer treatment and the underlying mechanisms have not been clarified. In this study, we found the sensitivity to erlotinib, a well-used EGFR-TKI, was correlated with basal autophagy level. Erlotinib was able to induce autophagy not only in TKI-sensitive, but also TKI-resistant cancer cells. Inhibition of autophagy significantly enhanced cytotoxicity of erlotinib in TKI-resistant cancer cells via modulation of endoplasmic reticulum (ER) stress induced apoptosis. In this process, CCAAT/enhancer binding protein homologous protein (CHOP) acted as an executioner. Downregulation of CHOP with siRNA blocked the autophagy inhibition and erlotinib co-treatment induced apoptosis and prevented cancer cells from this co-treatment-induced cell death. Our findings suggest that autophagy inhibition overcomes erlotinib resistance through modulation of ER stress mediated apoptosis. PMID:27035631

  8. Autophagy in DNA Damage Response

    Directory of Open Access Journals (Sweden)

    Piotr Czarny

    2015-01-01

    Full Text Available DNA damage response (DDR involves DNA repair, cell cycle regulation and apoptosis, but autophagy is also suggested to play a role in DDR. Autophagy can be activated in response to DNA-damaging agents, but the exact mechanism underlying this activation is not fully understood, although it is suggested that it involves the inhibition of mammalian target of rapamycin complex 1 (mTORC1. mTORC1 represses autophagy via phosphorylation of the ULK1/2–Atg13–FIP200 complex thus preventing maturation of pre-autophagosomal structures. When DNA damage occurs, it is recognized by some proteins or their complexes, such as poly(ADPribose polymerase 1 (PARP-1, Mre11–Rad50–Nbs1 (MRN complex or FOXO3, which activate repressors of mTORC1. SQSTM1/p62 is one of the proteins whose levels are regulated via autophagic degradation. Inhibition of autophagy by knockout of FIP200 results in upregulation of SQSTM1/p62, enhanced DNA damage and less efficient damage repair. Mitophagy, one form of autophagy involved in the selective degradation of mitochondria, may also play role in DDR. It degrades abnormal mitochondria and can either repress or activate apoptosis, but the exact mechanism remains unknown. There is a need to clarify the role of autophagy in DDR, as this process may possess several important biomedical applications, involving also cancer therapy.

  9. Autophagy and intestinal homeostasis.

    Science.gov (United States)

    Patel, Khushbu K; Stappenbeck, Thaddeus S

    2013-01-01

    Nutrient absorption is the basic function that drives mammalian intestinal biology. To facilitate nutrient uptake, the host's epithelial barrier is composed of a single layer of cells. This constraint is problematic, as a design of this type can be easily disrupted. The solution during the course of evolution was to add numerous host defense mechanisms that can help prevent local and systemic infection. These mechanisms include specialized epithelial cells that produce a physiochemical barrier overlying the cellular barrier, robust and organized adaptive and innate immune cells, and the ability to mount an inflammatory response that is commensurate with a specific threat level. The autophagy pathway is a critical cellular process that strongly influences all these functions. Therefore, a fundamental understanding of the components of this pathway and their influence on inflammation, immunity, and barrier function will facilitate our understanding of homeostasis in the gastrointestinal tract. PMID:23216414

  10. Neem oil limonoids induces p53-independent apoptosis and autophagy.

    Science.gov (United States)

    Srivastava, Pragya; Yadav, Neelu; Lella, Ravi; Schneider, Andrea; Jones, Anthony; Marlowe, Timothy; Lovett, Gabrielle; O'Loughlin, Kieran; Minderman, Hans; Gogada, Raghu; Chandra, Dhyan

    2012-11-01

    Azadirachta indica, commonly known as neem, has a wide range of medicinal properties. Neem extracts and its purified products have been examined for induction of apoptosis in multiple cancer cell types; however, its underlying mechanisms remain undefined. We show that neem oil (i.e., neem), which contains majority of neem limonoids including azadirachtin, induced apoptotic and autophagic cell death. Gene silencing demonstrated that caspase cascade was initiated by the activation of caspase-9, whereas caspase-8 was also activated late during neem-induced apoptosis. Pretreatment of cancer cells with pan caspase inhibitor, z-VAD inhibited activities of both initiator caspases (e.g., caspase-8 and -9) and executioner caspase-3. Neem induced the release of cytochrome c and apoptosis-inducing factor (AIF) from mitochondria, suggesting the involvement of both caspase-dependent and AIF-mediated apoptosis. p21 deficiency caused an increase in caspase activities at lower doses of neem, whereas p53 deficiency did not modulate neem-induced caspase activation. Additionally, neem treatment resulted in the accumulation of LC3-II in cancer cells, suggesting the involvement of autophagy in neem-induced cancer cell death. Low doses of autophagy inhibitors (i.e., 3-methyladenine and LY294002) did not prevent accumulation of neem-induced LC3-II in cancer cells. Silencing of ATG5 or Beclin-1 further enhanced neem-induced cell death. Phosphoinositide 3-kinase (PI3K) or autophagy inhibitors increased neem-induced caspase-3 activation and inhibition of caspases enhanced neem-induced autophagy. Together, for the first time, we demonstrate that neem induces caspase-dependent and AIF-mediated apoptosis, and autophagy in cancer cells. PMID:22915764

  11. Targeted pulmonary delivery of inducers of host macrophage autophagy as a potential host-directed chemotherapy of tuberculosis.

    Science.gov (United States)

    Gupta, Anuradha; Misra, Amit; Deretic, Vojo

    2016-07-01

    One of the promising host-directed chemotherapeutic interventions in tuberculosis (TB) is based on inducing autophagy as an immune effector. Here we consider the strengths and weaknesses of potential autophagy-based pharmacological intervention. Using the existing drugs that induce autophagy is an option, but it has limitations given the broad role of autophagy in most cells, tissues, and organs. Thus, it may be desirable that the agent being used to modulate autophagy is applied in a targeted manner, e.g. delivered to affected tissues, with infected macrophages being an obvious choice. This review addresses the advantages and disadvantages of delivering drugs to induce autophagy in M. tuberculosis-infected macrophages. One option, already being tested in models, is to design particles for inhalation delivery to lung macrophages. The choice of drugs, drug release kinetics and intracellular residence times, non-target cell exposure and feasibility of use by patients is discussed. We term here this (still experimental) approach, of compartment-targeting, autophagy-based, host-directed therapy as "Track-II antituberculosis chemotherapy." PMID:26829287

  12. Autophagy inhibition in endogenous and nutrient-deprived conditions reduces dorsal root ganglia neuron survival and neurite growth in vitro.

    Science.gov (United States)

    Clarke, Joseph-Patrick; Mearow, Karen

    2016-07-01

    Peripheral neuropathies can result in cytoskeletal changes in axons, ultimately leading to Wallerian degeneration and cell death. Recently, autophagy has been studied as a potential target for improving axonal survival and growth during peripheral nerve damage. This study investigates the influence of autophagy on adult dorsal root ganglia (DRG) neuron survival and axonal growth under control and nutrient deprivation conditions. Constitutive autophagy was modulated with pharmacological activators (rapamycin; Rapa) and inhibitors (3-methyladenine, bafilomycin A1) in conjunction with either a nutrient-stable environment (standard culture medium) or a nutrient-deprived environment (Hank's balanced salt solution + Ca(2+) /Mg(2+) ). The results demonstrated that autophagy inhibition decreased cell viability and reduced neurite growth and branching complexity. Although autophagy was upregulated with nutrient deprivation compared with the control, it was not further activated by rapamycin, suggesting a threshold level of autophagy. Overall, both cellular and biochemical approaches combined to show the influence of autophagy on adult DRG neuron survival and growth. © 2016 Wiley Periodicals, Inc. PMID:27018986

  13. Zymophagy: Selective Autophagy of Secretory Granules

    Directory of Open Access Journals (Sweden)

    Maria I. Vaccaro

    2012-01-01

    Full Text Available Timing is everything. That's especially true when it comes to the activation of enzymes created by the pancreas to break down food. Pancreatic enzymes are packed in secretory granules as precursor molecules called zymogens. In physiological conditions, those zymogens are activated only when they reach the gut, where they get to work releasing and distributing nutrients that we need to survive. If this process fails and the enzymes are prematurely activated within the pancreatic cell, before they are released from the gland, they break down the pancreas itself causing acute pancreatitis. This is a painful disease that ranges from a mild and autolimited process to a severe and lethal condition. Recently, we demonstrated that the pancreatic acinar cell is able to switch on a refined mechanism that could explain the autolimited form of the disease. This is a novel selective form of autophagy named zymophagy, a cellular process to specifically detect and degrade secretory granules containing activated enzymes before they can digest the organ. In this work, we revise the molecules and mechanisms that mediate zymophagy, a selective autophagy of secretory granules.

  14. Autophagy and apoptosis: rivals or mates?

    Institute of Scientific and Technical Information of China (English)

    Yan Cheng; Jin-Ming Yang

    2013-01-01

    Autophagy,a cellular process of "self-eating" by which intracellular components are degraded within the lysosome,is an evolutionarily conserved response to various stresses.Autophagy is associated with numerous patho-physiological conditions,and dysregulation of autophagy contributes to the pathogenesis of a variety of human diseases including cancer.Depending on context,activation of autophagy may promote either cell survival or death,two major events that determine pathological process of many illnesses.Importantly,the activity of autophagy is often associated with apoptosis,another critical cellular process determining cellular fate.A better understanding of biology of autophagy and its implication in human health and disorder,as well as the relationship between autophagy and apoptosis,has the potential of facilitating the development of autophagy-based therapeutic interventions for human diseases such as cancer.

  15. Fluorescence microscopy: A tool to study autophagy

    Science.gov (United States)

    Rai, Shashank; Manjithaya, Ravi

    2015-08-01

    Autophagy is a cellular recycling process through which a cell degrades old and damaged cellular components such as organelles and proteins and the degradation products are reused to provide energy and building blocks. Dysfunctional autophagy is reported in several pathological situations. Hence, autophagy plays an important role in both cellular homeostasis and diseased conditions. Autophagy can be studied through various techniques including fluorescence based microscopy. With the advancements of newer technologies in fluorescence microscopy, several novel processes of autophagy have been discovered which makes it an essential tool for autophagy research. Moreover, ability to tag fluorescent proteins with sub cellular targets has enabled us to evaluate autophagy processes in real time under fluorescent microscope. In this article, we demonstrate different aspects of autophagy in two different model organisms i.e. yeast and mammalian cells, with the help of fluorescence microscopy.

  16. Autophagy and apoptosis: rivals or mates?

    Directory of Open Access Journals (Sweden)

    Yan Cheng

    2013-03-01

    Full Text Available Autophagy, a cellular process of "self-eating" by which intracellular components are degraded within the lysosome, is an evolutionarily conserved response to various stresses. Autophagy is associated with numerous patho-physiological conditions, and dysregulation of autophagy contributes to the pathogenesis of a variety of human diseases including cancer. Depending on context, activation of autophagy may promote either cell survival or death, two major events that determine pathological process of many illnesses. Importantly, the activity of autophagy is often associated with apoptosis, another critical cellular process determining cellular fate. A better understanding of biology of autophagy and its implication in human health and disorder, as well as the relationship between autophagy and apoptosis, has the potential of facilitating the development of autophagy-based therapeutic interventions for human diseases such as cancer.

  17. Pseudomonas toxin pyocyanin triggers autophagy: Implications for pathoadaptive mutations.

    Science.gov (United States)

    Yang, Zhong-Shan; Ma, Lan-Qing; Zhu, Kun; Yan, Jin-Yuan; Bian, Li; Zhang, Ke-Qin; Zou, Cheng-Gang

    2016-06-01

    Pseudomonas aeruginosa can establish life-long chronic infection in patients with cystic fibrosis by generating genetic loss-of-function mutations, which enhance fitness of the bacterium in the airways. However, the precise role of the pathoadaptive mutations in persistence in chronic airways infection remains largely unknown. Here we demonstrate that pyocyanin, a well-described P. aeruginosa virulence factor that plays an important role in the initial infection, promotes autophagy in bronchial epithelial cells. Disruption of phzM, which is required for pyocyanin biosynthesis, leads to a significant reduction in autophagy in Beas-2B cells and lung tissues. Pyocyanin-induced autophagy is mediated by the EIF2AK4/GCN2-EIF2S1/eIF2α-ATF4 pathway. Interestingly, rats infected with the phzMΔ mutant strain have high mortality rate and numbers of colony-forming units, compared to those infected with wild-type (WT) P. aeruginosa PA14 strain, during chronic P. aeruginosa infection. In addition, the phzMΔ mutant strain induces more extensive alveolar wall thickening than the WT strain in the pulmonary airways of rats. As autophagy plays an essential role in suppressing bacterial burden, our findings provide a detailed understanding of why reduction of pyocyanin production in P. aeruginosa in chronic airways infections has been associated with better host adaptation and worse outcomes in cystic fibrosis. PMID:27159636

  18. Retinoid receptor signaling and autophagy in acute promyelocytic leukemia.

    LENUS (Irish Health Repository)

    Orfali, Nina

    2014-05-15

    Retinoids are a family of signaling molecules derived from vitamin A with well established roles in cellular differentiation. Physiologically active retinoids mediate transcriptional effects on cells through interactions with retinoic acid (RARs) and retinoid-X (RXR) receptors. Chromosomal translocations involving the RARα gene, which lead to impaired retinoid signaling, are implicated in acute promyelocytic leukemia (APL). All-trans-retinoic acid (ATRA), alone and in combination with arsenic trioxide (ATO), restores differentiation in APL cells and promotes degradation of the abnormal oncogenic fusion protein through several proteolytic mechanisms. RARα fusion-protein elimination is emerging as critical to obtaining sustained remission and long-term cure in APL. Autophagy is a degradative cellular pathway involved in protein turnover. Both ATRA and ATO also induce autophagy in APL cells. Enhancing autophagy may therefore be of therapeutic benefit in resistant APL and could broaden the application of differentiation therapy to other cancers. Here we discuss retinoid signaling in hematopoiesis, leukemogenesis, and APL treatment. We highlight autophagy as a potential important regulator in anti-leukemic strategies.

  19. DAMPs and autophagy: cellular adaptation to injury and unscheduled cell death.

    Science.gov (United States)

    Zhang, Qiuhong; Kang, Rui; Zeh, Herbert J; Lotze, Michael T; Tang, Daolin

    2013-04-01

    Autophagy is a lysosome-mediated catabolic process involving the degradation of intracellular contents (e.g., proteins and organelles) as well as invading microbes (e.g., parasites, bacteria and viruses). Multiple forms of cellular stress can stimulate this pathway, including nutritional imbalances, oxygen deprivation, immunological response, genetic defects, chromosomal anomalies and cytotoxic stress. Damage-associated molecular pattern molecules (DAMPs) are released by stressed cells undergoing autophagy or injury, and act as endogenous danger signals to regulate the subsequent inflammatory and immune response. A complex relationship exists between DAMPs and autophagy in cellular adaption to injury and unscheduled cell death. Since both autophagy and DAMPs are important for pathogenesis of human disease, it is crucial to understand how they interplay to sustain homeostasis in stressful or dangerous environments. PMID:23388380

  20. The transporter-mediated cellular uptake of pharmaceutical drugs is based on their metabolite-likeness and not on their bulk biophysical properties: Towards a systems pharmacology

    Directory of Open Access Journals (Sweden)

    Douglas B. Kell

    2015-12-01

    Full Text Available Several recent developments are brought together: (i the new availability of a consensus, curated human metabolic network reconstruction (Recon2, approximately a third of whose steps are represented by transporters, (ii the recognition that most successful (marketed drugs, as well as natural products, bear significant similarities to the metabolites in Recon2, (iii the recognition that to get into and out of cells such drugs hitchhike on the transporters that are part of normal intermediary metabolism, and the consequent recognition that for intact biomembrane Phospholipid Bilayer diffusion Is Negligible (PBIN, and (iv the consequent recognition that we need to exploit this and to use more phenotypic assays to understand how drugs affect cells and organisms. I show in particular that lipophilicity is a very poor predictor of drug permeability, and that we need to (and can bring together our knowledge of both pharmacology and systems biology modelling into a new systems pharmacology.

  1. Autophagy and senescence, stress responses induced by the DNA-damaging mycotoxin alternariol

    International Nuclear Information System (INIS)

    Highlights: • AOH induces autophagy, lamellar bodies and senescence in RAW264.7 macrophages. • DNA damage is suggested as a triggering signal. • The Sestrin2-AMPK-mTOR-S6K pathway is proposed to link DNA damage to autophagy. - Abstract: The mycotoxin alternariol (AOH), a frequent contaminant in fruit and grain, is known to induce cellular stress responses such as reactive oxygen production, DNA damage and cell cycle arrest. Cellular stress is often connected to autophagy, and we employed the RAW264.7 macrophage model to test the hypothesis that AOH induces autophagy. Indeed, AOH treatment led to a massive increase in acidic vacuoles often observed upon autophagy induction. Moreover, expression of the autophagy marker LC3 was markedly increased and there was a strong accumulation of LC3-positive puncta. Increased autophagic activity was verified biochemically by measuring the degradation rate of long-lived proteins. Furthermore, AOH induced expression of Sestrin2 and phosphorylation of AMPK as well as reduced phosphorylation of mTOR and S6 kinase, common mediators of signaling pathways involved in autophagy. Transmission electron microscopy analyzes of AOH treated cells not only clearly displayed structures associated with autophagy such as autophagosomes and autolysosomes, but also the appearance of lamellar bodies. Prolonged AOH treatment resulted in changed cell morphology from round into more star-shaped as well as increased β-galactosidase activity. This suggests that the cells eventually entered senescence. In conclusion, our data identify here AOH as an inducer of both autophagy and senescence. These effects are suggested to be to be linked to AOH-induced DSB (via a reported effect on topoisomerase activity), resulting in an activation of p53 and the Sestrin2-AMPK-mTOR-S6K signaling pathway

  2. DRAM1 Protects Neuroblastoma Cells from Oxygen-Glucose Deprivation/Reperfusion-Induced Injury via Autophagy

    Directory of Open Access Journals (Sweden)

    Mengqiang Yu

    2014-10-01

    Full Text Available DNA damage-regulated autophagy modulator protein 1 (DRAM1, a multi-pass membrane lysosomal protein, is reportedly a tumor protein p53 (TP53 target gene involved in autophagy. During cerebral ischemia/reperfusion (I/R injury, DRAM1 protein expression is increased, and autophagy is activated. However, the functional significance of DRAM1 and the relationship between DRAM1 and autophagy in brain I/R remains uncertain. The aim of this study is to investigate whether DRAM1 mediates autophagy activation in cerebral I/R injury and to explore its possible effects and mechanisms. We adopt the oxygen-glucose deprivation and reperfusion (OGD/R Neuro-2a cell model to mimic cerebral I/R conditions in vitro, and RNA interference is used to knock down DRAM1 expression in this model. Cell viability assay is performed using the LIVE/DEAD viability/cytotoxicity kit. Cell phenotypic changes are analyzed through Western blot assays. Autophagy flux is monitored through the tandem red fluorescent protein–Green fluorescent protein–microtubule associated protein 1 light chain 3 (RFP–GFP–LC3 construct. The expression levels of DRAM1 and microtubule associated protein 1 light chain 3II/I (LC3II/I are strongly up-regulated in Neuro-2a cells after OGD/R treatment and peaked at the 12 h reperfusion time point. The autophagy-specific inhibitor 3-Methyladenine (3-MA inhibits the expression of DRAM1 and LC3II/I and exacerbates OGD/R-induced cell injury. Furthermore, DRAM1 knockdown aggravates OGD/R-induced cell injury and significantly blocks autophagy through decreasing autophagosome-lysosome fusion. In conclusion, our data demonstrate that DRAM1 knockdown in Neuro-2a cells inhibits autophagy by blocking autophagosome-lysosome fusion and exacerbated OGD/R-induced cell injury. Thus, DRAM1 might constitute a new therapeutic target for I/R diseases.

  3. Autophagy: for better or for worse

    OpenAIRE

    Wirawan, Ellen; Berghe, Tom Vanden; Lippens, Saskia; Agostinis, Patrizia; Vandenabeele, Peter

    2011-01-01

    Autophagy is a lysosomal degradation pathway that degrades damaged or superfluous cell components into basic biomolecules, which are then recycled back into the cytosol. In this respect, autophagy drives a flow of biomolecules in a continuous degradation-regeneration cycle. Autophagy is generally considered a pro-survival mechanism protecting cells under stress or poor nutrient conditions. Current research clearly shows that autophagy fulfills numerous functions in vital biological processes....

  4. Autophagy and mitophagy in cellular damage control

    Directory of Open Access Journals (Sweden)

    Jianhua Zhang

    2013-01-01

    Full Text Available Autophagy and mitophagy are important cellular processes that are responsible for breaking down cellular contents, preserving energy and safeguarding against accumulation of damaged and aggregated biomolecules. This graphic review gives a broad summary of autophagy and discusses examples where autophagy is important in controlling protein degradation. In addition we highlight how autophagy and mitophagy are involved in the cellular responses to reactive species and mitochondrial dysfunction. The key signaling pathways for mitophagy are described in the context of bioenergetic dysfunction.

  5. EGFR-independent autophagy induction with gefitinib and enhancement of its cytotoxic effect by targeting autophagy with clarithromycin in non-small cell lung cancer cells.

    Science.gov (United States)

    Sugita, Shohei; Ito, Kentaro; Yamashiro, Yutaro; Moriya, Shota; Che, Xiao-Fang; Yokoyama, Tomohisa; Hiramoto, Masaki; Miyazawa, Keisuke

    2015-05-22

    Gefitinib (GEF), an inhibitor for EGFR tyrosine kinase, potently induces autophagy in non-small cell lung cancer (NSCLC) cell lines such as PC-9 cells expressing constitutively activated EGFR kinase by EGFR gene mutation as well as A549 and H226 cells with wild-type EGFR. Unexpectedly, GEF-induced autophagy was also observed in non-NSCLC cells such as murine embryonic fibroblasts (MEF) and leukemia cell lines K562 and HL-60 without EGFR expression. Knockout of EGFR gene in A549 cells by CRISPR/Cas9 system still exhibited autophagy induction after treatment with GEF, indicating that the autophagy induction by GEF is not mediated through inhibiting EGFR kinase activity. Combined treatment with GEF and clarithromycin (CAM), a macrolide antibiotic having the effect of inhibiting autophagy flux, enhances the cytotoxic effect in NSCLC cell lines, although treatment with CAM alone exhibits no cytotoxicity. GEF treatment induced up-regulation of endoplasmic reticulum (ER)-stress related genes such as CHOP/GADD153 and GRP78. Knockdown of CHOP in PC-9 cells and Chop-knockout MEF both exhibited less sensitivity to GEF than controls. Addition of CAM in culture medium resulted in further pronounced GEF-induced ER stress loading, while CAM alone exhibited no effect. These data suggest that GEF-induced autophagy functions as cytoprotective and indicates the potential therapeutic possibility of using CAM for GEF therapy. Furthermore, it is suggested that the intracellular signaling for autophagy initiation in response to GEF can be completely dissociated from EGFR, but unknown target molecule(s) of GEF for autophagy induction might exist. PMID:25858318

  6. Possible Role of Autophagy in the Treatment of Pancreatic Cancer with Histone Deacetylase Inhibitors

    International Nuclear Information System (INIS)

    Pancreatic cancer is a lethal disease and notoriously difficult to treat. Only a small proportion is curative by surgical resection, whilst standard chemotherapy for patients with advanced disease has only a modest effect with substantial toxicity. Clearly there is a need for the continual development of novel therapeutic agents to improve the current situation. Currently, there is a bulk of data indicating the important function of autophagy in cancer. While genetic evidence indicates that autophagy functions as a tumor suppressor, it is also apparent that autophagy can promote the survival of established tumors under stress conditions and in response to chemotherapy. This review provides a spectrum of potential pharmacological agents and autophagic approaches to enhance cell killing in pancreatic cancer

  7. Ocular pharmacology.

    Science.gov (United States)

    Novack, Gary D; Robin, Alan L

    2016-05-01

    Ophthalmic diseases include both those analogous to systemic diseases (eg, inflammation, infection, neuronal degeneration) and not analogous (eg, cataract, myopia). Many anterior segment diseases are treated pharmacologically through eye drops, which have an implied therapeutic index of local therapy. Unlike oral dosage forms administered for systemic diseases, eyedrops require patients not only to adhere to treatment, but to be able to accurately perform-ie, instill drops correctly. Anatomical and physiological barriers make topical delivery to the anterior chamber challenging-in some cases more challenging than absorption through the skin, nasal passages, or gut. Treatment of the posterior segment (eg, vitreous, retina, choroid, and optic nerve) is more challenging due to additional barriers. Recently, intravitreal injections have become a standard of care with biologics for the treatment of macular degeneration and other diseases. Although the eye has esterases, hydroxylases, and transporters, it has relatively little CYP450 enzymes. Because it is challenging to obtain drug concentrations at the target site, ocular clinical pharmacokinetics, and thus pharmacokinetic-pharmacodynamic interactions, are rarely available. Ophthalmic pharmaceuticals require consideration of solubility, physiological pH, and osmolarity, as well as sterility and stability, which in turn requires optimal pharmaceutics. Although applied locally, ocular medications may be absorbed systemically, which results in morbidity and mortality (eg, systemic hypotension, bronchospasm, and bradycardia). PMID:26360129

  8. Autophagy in the Pathogenesis of Disease

    OpenAIRE

    Levine, Beth; Kroemer, Guido

    2008-01-01

    Autophagy is a lysosomal degradation pathway that is essential for survival, differentiation, development, and homeostasis. Autophagy principally serves an adaptive role to protect organisms against diverse pathologies, including infections, cancer, neurodegeneration, aging, and heart disease. However, in certain experimental disease settings, the self-cannibalistic or, paradoxically, even the prosurvival functions of autophagy may be deleterious. This Review summarizes recent advances in und...

  9. p53: The Janus of autophagy?

    OpenAIRE

    Levine, Beth; Abrams, John

    2008-01-01

    The autophagy pathway functions in adaptation to nutrient stress and tumour suppression. The p53 tumour suppressor, previously thought to positively regulate autophagy, may also inhibit it. This dual interplay between p53 and autophagy regulation is enigmatic, but may underlie key aspects of metabolism and cancer biology.

  10. Streptococcus pneumoniae induces autophagy through the inhibition of the PI3K-I/Akt/mTOR pathway and ROS hypergeneration in A549 cells.

    Directory of Open Access Journals (Sweden)

    Pu Li

    Full Text Available The present study focused on the action mechanism of S. pneumoniae (Sp in inducing autophagy in human alveolar epithelial cells. Sp, a gram-positive extracellular bacterium, activates autophagy with considerably increased microtuble-associated protein light chain 3 (LC3 punctation in A549 cells. The accumulation of typical autophagosomes and conjugation of LC3 to phosphatidylethanolamine were observed in Sp-infected cells as an indication of autophagy. Using the pneumolysin (PLY mutant, we successfully demonstrated that PLY is involved in initiating autophagy without affecting the expression levels of PI3K-III and Beclin1. PLY-mediated autophagy depends on the inhibition of the phosphoinositide 3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR pathway. Furthermore, Sp could also lead to the reactive oxygen species (ROS hypergeneration in A549 cells. Taken together, Sp infection-induced autophagy is PLY-mediated through ROS hypergeneration and mTOR inhibition. PI3K-I and rapamycin (autophagy inducers enhanced bacterial clearance, whereas wortmannin (autophagy inhibitor and acetylcysteine (ROS inhibitor reduced intracellular bacteria clearance. Thus, Sp-induced autophagy represents a host-protective mechanism, providing new insight into the pathogenesis of respiratory tract Sp infection.

  11. MAVS maintains mitochondrial homeostasis via autophagy.

    Science.gov (United States)

    Sun, Xiaofeng; Sun, Liwei; Zhao, Yuanyuan; Li, Ying; Lin, Wei; Chen, Dahua; Sun, Qinmiao

    2016-01-01

    Mitochondrial antiviral signalling protein (MAVS) acts as a critical adaptor protein to transduce antiviral signalling by physically interacting with activated RIG-I and MDA5 receptors. MAVS executes its functions at the outer membrane of mitochondria to regulate downstream antiviral signalling, indicating that the mitochondria provides a functional platform for innate antiviral signalling transduction. However, little is known about whether and how MAVS-mediated antiviral signalling contributes to mitochondrial homeostasis. Here we show that the activation of MAVS is sufficient to induce autophagic signalling, which may mediate the turnover of the damaged mitochondria. Importantly, we find MAVS directly interacts with LC3 through its LC3-binding motif 'YxxI', suggesting that MAVS might act as an autophagy receptor to mediate mitochondrial turnover upon excessive activation of RLR signalling. Furthermore, we provide evidence that both MAVS self-aggregation and its interaction with TRAF2/6 proteins are important for MAVS-mediated mitochondrial turnover. Collectively, our findings suggest that MAVS acts as a potential receptor for mitochondria-associated autophagic signalling to maintain mitochondrial homeostasis. PMID:27551434

  12. The cellular decision between apoptosis and autophagy

    Directory of Open Access Journals (Sweden)

    Yong-Jun Fan

    2013-03-01

    Full Text Available Apoptosis and autophagy are important molecular processes that maintain organismal and cellular homeostasis, respectively. While apoptosis fulfills its role through dismantling damaged or unwanted cells, autophagy maintains cellular homeostasis through recycling selective intracellular organelles and molecules. Yet in some conditions, autophagy can lead to cell death. Apoptosis and autophagy can be stimulated by the same stresses. Emerging evidence indicates an interplay between the core proteins in both pathways, which underlies the molecular mechanism of the crosstalk between apoptosis and autophagy. This review summarizes recent literature on molecules that regulate both the apoptotic and autophagic processes.

  13. Pharmacological profile of the ATP-mediated increase in L-type calcium current amplitude and activation of a non-specific cationic current in rat ventricular cells.

    OpenAIRE

    Scamps, F.; Vassort, G

    1994-01-01

    1. The pharmacological profile of the ATP-induced increase in ICa amplitude and of ATP activation of a non-specific cationic current, IATP, was investigated in rat ventricular cells. 2. The EC50 values for ICa increase and IATP activation were 0.36 microM and 0.76 microM respectively. Suramin (10 microM) and cibacron blue (1 microM) competitively antagonized both effects of ATP. 3. The rank order of efficacy and potency of ATP analogues in increasing ICa amplitude was 2-methylthio-ATP approxi...

  14. Advances in Autophagy Regulatory Mechanisms

    Directory of Open Access Journals (Sweden)

    Laura E. Gallagher

    2016-05-01

    Full Text Available Autophagy plays a critical role in cell metabolism by degrading and recycling internal components when challenged with limited nutrients. This fundamental and conserved mechanism is based on a membrane trafficking pathway in which nascent autophagosomes engulf cytoplasmic cargo to form vesicles that transport their content to the lysosome for degradation. Based on this simple scheme, autophagy modulates cellular metabolism and cytoplasmic quality control to influence an unexpectedly wide range of normal mammalian physiology and pathophysiology. In this review, we summarise recent advancements in three broad areas of autophagy regulation. We discuss current models on how autophagosomes are initiated from endogenous membranes. We detail how the uncoordinated 51-like kinase (ULK complex becomes activated downstream of mechanistic target of rapamycin complex 1 (MTORC1. Finally, we summarise the upstream signalling mechanisms that can sense amino acid availability leading to activation of MTORC1.

  15. Advances in Autophagy Regulatory Mechanisms.

    Science.gov (United States)

    Gallagher, Laura E; Williamson, Leon E; Chan, Edmond Y W

    2016-01-01

    Autophagy plays a critical role in cell metabolism by degrading and recycling internal components when challenged with limited nutrients. This fundamental and conserved mechanism is based on a membrane trafficking pathway in which nascent autophagosomes engulf cytoplasmic cargo to form vesicles that transport their content to the lysosome for degradation. Based on this simple scheme, autophagy modulates cellular metabolism and cytoplasmic quality control to influence an unexpectedly wide range of normal mammalian physiology and pathophysiology. In this review, we summarise recent advancements in three broad areas of autophagy regulation. We discuss current models on how autophagosomes are initiated from endogenous membranes. We detail how the uncoordinated 51-like kinase (ULK) complex becomes activated downstream of mechanistic target of rapamycin complex 1 (MTORC1). Finally, we summarise the upstream signalling mechanisms that can sense amino acid availability leading to activation of MTORC1. PMID:27187479

  16. Modulation of pathogen recognition by autophagy

    Directory of Open Access Journals (Sweden)

    Ji Eun eOh

    2012-03-01

    Full Text Available Autophagy is an ancient biological process for maintaining cellular homeostasis by degradation of long-lived cytosolic proteins and organelles. Recent studies demonstrated that autophagy is availed by immune cells to regulate innate immunity. On the one hand, cells exert direct effector function by degrading intracellular pathogens; on the other hand, autophagy modulates pathogen recognition and downstream signaling for innate immune responses. Pathogen recognition via pattern recognition receptors induces autophagy. The function of phagocytic cells is enhanced by recruitment of autophagy-related proteins. Moreover, autophagy acts as a delivery system for viral replication complexes to migrate to the endosomal compartments where virus sensing occurs. In another case, key molecules of the autophagic pathway have been found to negatively regulate immune signaling, thus preventing aberrant activation of cytokine production and consequent immune responses. In this review, we focus on the recent advances in the role of autophagy in pathogen recognition and modulation of innate immune responses.

  17. mTOR Hyperactivation by Ablation of Tuberous Sclerosis Complex 2 in the Mouse Heart Induces Cardiac Dysfunction with the Increased Number of Small Mitochondria Mediated through the Down-Regulation of Autophagy

    Science.gov (United States)

    Taneike, Manabu; Nishida, Kazuhiko; Omiya, Shigemiki; Zarrinpashneh, Elham; Misaka, Tomofumi; Kitazume-Taneike, Rika; Austin, Ruth; Takaoka, Minoru; Yamaguchi, Osamu; Gambello, Michael J.; Shah, Ajay M.; Otsu, Kinya

    2016-01-01

    Mammalian target of rapamycin complex 1 (mTORC1) is a key regulator of cell growth, proliferation and metabolism. mTORC1 regulates protein synthesis positively and autophagy negatively. Autophagy is a major system to manage bulk degradation and recycling of cytoplasmic components and organelles. Tuberous sclerosis complex (TSC) 1 and 2 form a heterodimeric complex and inactivate Ras homolog enriched in brain, resulting in inhibition of mTORC1. Here, we investigated the effects of hyperactivation of mTORC1 on cardiac function and structure using cardiac-specific TSC2-deficient (TSC2-/-) mice. TSC2-/- mice were born normally at the expected Mendelian ratio. However, the median life span of TSC2-/- mice was approximately 10 months and significantly shorter than that of control mice. TSC2-/- mice showed cardiac dysfunction and cardiomyocyte hypertrophy without considerable fibrosis, cell infiltration or apoptotic cardiomyocyte death. Ultrastructural analysis of TSC2-/- hearts revealed misalignment, aggregation and a decrease in the size and an increase in the number of mitochondria, but the mitochondrial function was maintained. Autophagic flux was inhibited, while the phosphorylation level of S6 or eukaryotic initiation factor 4E -binding protein 1, downstream of mTORC1, was increased. The upregulation of autophagic flux by trehalose treatment attenuated the cardiac phenotypes such as cardiac dysfunction and structural abnormalities of mitochondria in TSC2-/- hearts. The results suggest that autophagy via the TSC2-mTORC1 signaling pathway plays an important role in maintenance of cardiac function and mitochondrial quantity and size in the heart and could be a therapeutic target to maintain mitochondrial homeostasis in failing hearts. PMID:27023784

  18. Historical landmarks of autophagy research

    OpenAIRE

    Ohsumi, Yoshinori

    2013-01-01

    The year of 2013 marked the 50th anniversary of C de Duve's coining of the term “autophagy” for the degradation process of cytoplasmic constituents in the lysosome/vacuole. This year we regretfully lost this great scientist, who contributed much during the early years of research to the field of autophagy. Soon after the discovery of lysosomes by de Duve, electron microscopy revealed autophagy as a means of delivering intracellular components to the lysosome. For a long time after the discove...

  19. Diabetes and the Brain: Oxidative Stress, Inflammation, and Autophagy

    Directory of Open Access Journals (Sweden)

    María Muriach

    2014-01-01

    Full Text Available Diabetes mellitus is a common metabolic disorder associated with chronic complications including a state of mild to moderate cognitive impairment, in particular psychomotor slowing and reduced mental flexibility, not attributable to other causes, and shares many symptoms that are best described as accelerated brain ageing. A common theory for aging and for the pathogenesis of this cerebral dysfunctioning in diabetes relates cell death to oxidative stress in strong association to inflammation, and in fact nuclear factor κB (NFκB, a master regulator of inflammation and also a sensor of oxidative stress, has a strategic position at the crossroad between oxidative stress and inflammation. Moreover, metabolic inflammation is, in turn, related to the induction of various intracellular stresses such as mitochondrial oxidative stress, endoplasmic reticulum (ER stress, and autophagy defect. In parallel, blockade of autophagy can relate to proinflammatory signaling via oxidative stress pathway and NFκB-mediated inflammation.

  20. Probiotic Lactobacillus rhamnosus GG mono-association suppresses human rotavirus-induced autophagy in the gnotobiotic piglet intestine

    OpenAIRE

    Wu, Shaoping; Yuan, Lijuan; Zhang, Yongguo; Liu, Fangning; Li, Guohua; Wen, Ke; Kocher, Jacob; Yang, Xingdong; Sun, Jun

    2013-01-01

    Abstract Background Human rotavirus (HRV) is the most important cause of severe diarrhea in infants and young children. Probiotic Lactobacillus rhamnosus GG (LGG) reduces rotavirus infection and diarrhea. However, the molecular mechanisms of LGG-mediated protection from rotavirus infection are poorly understood. Autophagy plays an essential role in responses to microbial pathogens. However, the role of autophagy in HRV infection and LGG treatment is unknown. We hypothesize that rotavirus gast...

  1. Ordered bulk degradation via autophagy

    DEFF Research Database (Denmark)

    Dengjel, Jörn; Kristensen, Anders Riis; Andersen, Jens S

    2008-01-01

    proteasomal and lysosomal degradation ample cross-talk between the two degradation pathways became evident. Degradation via autophagy appeared to be ordered and regulated at the protein complex/organelle level. This raises several important questions such as: can macroautophagy itself be specific and what is...

  2. Repetitive stimulation of autophagy-lysosome machinery by intermittent fasting preconditions the myocardium to ischemia-reperfusion injury.

    Science.gov (United States)

    Godar, Rebecca J; Ma, Xiucui; Liu, Haiyan; Murphy, John T; Weinheimer, Carla J; Kovacs, Attila; Crosby, Seth D; Saftig, Paul; Diwan, Abhinav

    2015-01-01

    Autophagy, a lysosomal degradative pathway, is potently stimulated in the myocardium by fasting and is essential for maintaining cardiac function during prolonged starvation. We tested the hypothesis that intermittent fasting protects against myocardial ischemia-reperfusion injury via transcriptional stimulation of the autophagy-lysosome machinery. Adult C57BL/6 mice subjected to 24-h periods of fasting, every other day, for 6 wk were protected from in-vivo ischemia-reperfusion injury on a fed day, with marked reduction in infarct size in both sexes as compared with nonfasted controls. This protection was lost in mice heterozygous null for Lamp2 (coding for lysosomal-associated membrane protein 2), which demonstrate impaired autophagy in response to fasting with accumulation of autophagosomes and SQSTM1, an autophagy substrate, in the heart. In lamp2 null mice, intermittent fasting provoked progressive left ventricular dilation, systolic dysfunction and hypertrophy; worsening cardiomyocyte autophagosome accumulation and lack of protection to ischemia-reperfusion injury, suggesting that intact autophagy-lysosome machinery is essential for myocardial homeostasis during intermittent fasting and consequent ischemic cardioprotection. Fasting and refeeding cycles resulted in transcriptional induction followed by downregulation of autophagy-lysosome genes in the myocardium. This was coupled with fasting-induced nuclear translocation of TFEB (transcription factor EB), a master regulator of autophagy-lysosome machinery; followed by rapid decline in nuclear TFEB levels with refeeding. Endogenous TFEB was essential for attenuation of hypoxia-reoxygenation-induced cell death by repetitive starvation, in neonatal rat cardiomyocytes, in-vitro. Taken together, these data suggest that TFEB-mediated transcriptional priming of the autophagy-lysosome machinery mediates the beneficial effects of fasting-induced autophagy in myocardial ischemia-reperfusion injury. PMID:26103523

  3. Research advances in ROS and autophagy%活性氧与自噬的研究进展

    Institute of Scientific and Technical Information of China (English)

    朱京; 谭晓荣

    2011-01-01

    活性氧(reactive oxygen species,ROS)和自噬在人体内作用广泛,且与人类的健康密切相关.两者之间关系复杂,ROS作为诱导自噬的信号分子,参与多种诱导自噬的信号途径,在自噬的形成过程中起着重要作用,而自噬具有减少ROS损伤的作用.对ROS与自噬之间的关系,包括ROS介导自噬的分子机制,以及ROS和自噬在肿瘤、神经退行性疾病和衰老中的作用进行综述.%Reactive oxygen species (ROS) and autophagy have an extensive role in the human body. As a signaling molecule involved in various signaling pathways induced autophagy, ROS plays an important role in the autophagy. ? In this article we discussed the relationship between autophagy and ROS, as well as the latest research progress of ROS-mediated molecular mechanism underlying ROS-mediated autophagy. The roles of ROS-mediated autophagy in cancer, neurodegenerative diseases and aging are also included.

  4. MARCH2 regulates autophagy by promoting CFTR ubiquitination and degradation and PIK3CA-AKT-MTOR signaling.

    Science.gov (United States)

    Xia, Dan; Qu, Liujing; Li, Ge; Hongdu, Beiqi; Xu, Chentong; Lin, Xin; Lou, Yaxin; He, Qihua; Ma, Dalong; Chen, Yingyu

    2016-09-01

    MARCH2 (membrane-associated RING-CH protein 2), an E3 ubiquitin ligase, is mainly associated with the vesicle trafficking. In the present study, for the first time, we demonstrated that MARCH2 negatively regulates autophagy. Our data indicated that overexpression of MARCH2 impaired autophagy, as evidenced by attenuated levels of LC3B-II and impaired degradation of endogenous and exogenous autophagic substrates. By contrast, loss of MARCH2 expression had the opposite effects. In vivo experiments demonstrate that MARCH2 knockout mediated autophagy results in an inhibition of tumorigenicity. Further investigation revealed that the induction of autophagy by MARCH2 deficiency was mediated through the PIK3CA-AKT-MTOR signaling pathway. Additionally, we found that MARCH2 interacts with CFTR (cystic fibrosis transmembrane conductance regulator), promotes the ubiquitination and degradation of CFTR, and inhibits CFTR-mediated autophagy in tumor cells. The functional PDZ domain of MARCH2 is required for the association with CFTR. Thus, our study identified a novel negative regulator of autophagy and suggested that the physical and functional connection between the MARCH2 and CFTR in different conditions will be elucidated in the further experiments. PMID:27308891

  5. Autophagy in muscle of glucose-infusion hyperglycemia rats and streptozotocin-induced hyperglycemia rats via selective activation of m-TOR or FoxO3.

    Directory of Open Access Journals (Sweden)

    Pengfei Lv

    Full Text Available Autophagy is a conserved process in eukaryotes required for metabolism and is involved in diverse diseases. To investigate autophagy in skeletal muscle under hyperglycemia status, we established two hyperglycemia-rat models that differ in their circulating insulin levels, by glucose infusion and singe high-dose streptozotocin injection. We then detected expression of autophagy related genes with real-time PCR and western blot. We found that under hyperglycemia status induced by glucose-infusion, autophagy was inhibited in rat skeletal muscle, whereas under streptozotocin-induced hyperglycemia status autophagy was enhanced. Meanwhile, hyperglycemic gastrocnemius muscle was more prone to autophagy than soleus muscle. Furthermore, inhibition of autophagy in skeletal muscle in glucose-infusion hyperglycemia rats was mediated by the m-TOR pathway while m-TOR and FoxO3 both contributed to enhancement of autophagy in gastrocnemius muscle in streptozotocin-induced hyperglycemia rats. These data shows that insulin plays a relatively more important role than hyperglycemia in regulating autophagy in hyperglycemia rat muscle through selectively activating the m-TOR or FoxO3 pathway in a fiber-selective manner.

  6. Silver nanoparticles impede phorbol myristate acetate-induced monocyte-macrophage differentiation and autophagy

    Science.gov (United States)

    Xu, Yingying; Wang, Liming; Bai, Ru; Zhang, Tianlu; Chen, Chunying

    2015-09-01

    Monocytes/macrophages are important constituents of the innate immune system. Monocyte-macrophage differentiation is not only crucial for innate immune responses, but is also related to some cardiovascular diseases. Silver nanoparticles (AgNPs) are one of the most widely used nanomaterials because of their broad-spectrum antimicrobial properties. However, the effect of AgNPs on the functions of blood monocytes is scarcely reported. Here, we report the impedance effect of AgNPs on THP-1 monocyte differentiation, and that this effect was mediated by autophagy blockade and lysosomal impairment. Firstly, AgNPs inhibit phorbol 12-myristate 13-acetate (PMA)-induced monocyte differentiation by down-regulating both expression of surface marker CD11b and response to lipopolysaccharide (LPS) stimulation. Secondly, autophagy is activated during PMA-induced THP-1 monocyte differentiation, and the autophagy inhibitor chloroquine (CQ) can inhibit this process. Thirdly, AgNPs block the degradation of the autophagy substrate p62 and induce autophagosome accumulation, which demonstrates the blockade of autophagic flux. Fourthly, lysosomal impairments including alkalization and decrease of lysosomal membrane stability were observed in AgNP-treated THP-1 cells. In conclusion, we demonstrate that the impedance of monocyte-macrophage differentiation by AgNPs is mediated by autophagy blockade and lysosomal dysfunction. Our results suggest that crosstalk exists in different biological effects induced by AgNPs.

  7. The anticancer effect of chaetocin is enhanced by inhibition of autophagy.

    Science.gov (United States)

    Jung, H-J; Seo, I; Casciello, F; Jacquelin, S; Lane, S W; Suh, S-Il; Suh, M-H; Lee, J S; Baek, W-K

    2016-01-01

    Chaetocin is a fungal metabolite that possesses a potent antiproliferative activity in solid tumors by inducing cell death. Although recent studies have extended the role of chaetocin in tumors, the underlying molecular mechanisms such as the downstream cascade that induces cell death has not clearly been elucidated. In this study, we show that chaetocin is able to induce both apoptosis and autophagy in several hepatoma cell lines including HepG2, Hep3B and Huh7 cell lines. Moreover, we found that the inhibition of caspase-3/7 activity by z-VAD-fmk treatment was able to block chaetocin-mediated cell death, whereas blocking autophagy by Bafilomycin A1 or the knockdown of autophagy protein 5 enhanced cell death mediated by chaetocin. These findings suggest that chaetocin has a potent anticancer effect against hepatoma. Inhibition of autophagy may potentiate anticancer effects of chaetocin thus providing evidence that combined treatment with chaetocin and autophagy inhibitors will be an effective strategy for treating cancer. PMID:26890137

  8. Increased autophagy and apoptosis contribute to muscle atrophy in a myotonic dystrophy type 1 Drosophila model

    Directory of Open Access Journals (Sweden)

    Ariadna Bargiela

    2015-07-01

    Full Text Available Muscle mass wasting is one of the most debilitating symptoms of myotonic dystrophy type 1 (DM1 disease, ultimately leading to immobility, respiratory defects, dysarthria, dysphagia and death in advanced stages of the disease. In order to study the molecular mechanisms leading to the degenerative loss of adult muscle tissue in DM1, we generated an inducible Drosophila model of expanded CTG trinucleotide repeat toxicity that resembles an adult-onset form of the disease. Heat-shock induced expression of 480 CUG repeats in adult flies resulted in a reduction in the area of the indirect flight muscles. In these model flies, reduction of muscle area was concomitant with increased apoptosis and autophagy. Inhibition of apoptosis or autophagy mediated by the overexpression of DIAP1, mTOR (also known as Tor or muscleblind, or by RNA interference (RNAi-mediated silencing of autophagy regulatory genes, achieved a rescue of the muscle-loss phenotype. In fact, mTOR overexpression rescued muscle size to a size comparable to that in control flies. These results were validated in skeletal muscle biopsies from DM1 patients in which we found downregulated autophagy and apoptosis repressor genes, and also in DM1 myoblasts where we found increased autophagy. These findings provide new insights into the signaling pathways involved in DM1 disease pathogenesis.

  9. Molecular mechanism and regulation of autophagy

    Institute of Scientific and Technical Information of China (English)

    Ya-ping YANG; Zhong-qin LIANG; Zhen-lun GU; Zheng-hong QIN

    2005-01-01

    Autophagy is a major cellular pathway for the degradation of long-lived proteins and cytoplasmic organelles in eukaryotic cells. A large number of intracellular/extracellular stimuli, including amino acid starvation and invasion of microorganisms, are able to induce the autophagic response in cells. The discovery of the ATG genes in yeast has greatly advanced our understanding of the molecular mechanisms participating in autophagy and the genes involved in regulating the autophagic pathway. Many yeast genes have mammalian homologs,suggesting that the basic machinery for autophagy has been evolutionarily conserved along the eukaryotic phylum. The regulation of autophagy is a very complex process. Many signaling pathways, including target of rapamycin (TOR) or mammalian target of rapamycin (mTOR), phosphatidylinositol 3-kinase-I (PI3K-I)/PKB, GTPases, calcium and protein synthesis all play important roles in regulating autophagy. The molecular mechanisms and regulation of autophagy are discussed in this review.

  10. Inhibiting ROS-STAT3-dependent autophagy enhanced capsaicin-induced apoptosis in human hepatocellular carcinoma cells.

    Science.gov (United States)

    Chen, Xun; Tan, Miduo; Xie, Zhiqin; Feng, Bin; Zhao, Zhijian; Yang, Kaiqing; Hu, Chen; Liao, Ni; Wang, Taoli; Chen, Dongliang; Xie, Feng; Tang, Caixi

    2016-07-01

    Capsaicin, which is the pungent ingredient of red hot chili peppers, has been reported to possess anticancer activity, including that against hepatocellular carcinoma. However, the precise molecular mechanisms by which capsaicin exerts its anticancer effects remain poorly understood. Herein, we have tested the involvement of autophagy in the capsaicin mechanism of action in human hepatocellular carcinoma. HepG2 cancer cells were treated with different doses of capsaicin (50, 100 and 200μmol/L) for 6, 12, and 24 h. Flow cytometry and Caspase-3 activity assay were performed to determine cell apoptosis. Immunofluorescence was performed to visualize LC3-positive puncta. Western blotting was used to detect the expression of the hallmarks of apoptosis and autophagy. Capsaicin can induce apoptosis in HepG2 cells. The expression levels of CL-PARP and Bcl-2 were significantly increased. In line with the apoptosis, capsaicin can trigger autophagy in HepG2 cells. Capsaicin increased LC3-II and beclin-1 expression and GFP-LC3-positive autophagosomes. Pharmacological or genetic inhibition of autophagy further sensitized HepG2 cells to capsaicin-induced apoptosis. Mechanistically, capsaicin upregulated the Stat3 activity which contributed to autophagy. Importantly, we found that capsaicin triggered reactive oxygen species (ROS) generation in hepatoma cells and that the levels of ROS decreased with N-acetyl-cysteine (NAC), a ROS scavenger. Moreover, NAC abrogated the effects of capsaicin on Stat3-dependent autophagy. In this study, we demonstrated that capsaicin increased the phosphorylation of signal transducer and activator of transcription 3 (p-STAT3)-dependent autophagy through the generation of ROS signaling pathways in human hepatoma. Inhibiting autophagy could enhance capsaicin-induced apoptosis in human hepatocellular carcinoma. PMID:27043357

  11. Pharmacological reversal of endothelin-1 mediated constriction of the spiral modiolar artery: a potential new treatment for sudden sensorineural hearing loss

    Directory of Open Access Journals (Sweden)

    Arnold Wolfgang

    2005-11-01

    Full Text Available Abstract Background Vasospasm of the spiral modiolar artery (SMA may cause ischemic stroke of the inner ear. Endothelin-1 (ET-1 induces a strong, long-lasting constriction of the SMA by increasing contractile apparatus Ca2+ sensitivity via Rho-kinase. We therefore tested several Rho-kinase inhibitors and a cell-permeable analogue of cAMP (dbcAMP for their ability to reverse ET-1-induced constriction and Ca2+-sensitization. Methods The present study employed SMA isolated from gerbil temporal bones. Ca2+sensitivity was evaluated by correlating vascular diameter and smooth muscle cell [Ca2+]i, measured by fluo-4-microfluorometry and videomicroscopy. Results The Rho-kinase inhibitors Y-27632, fasudil, and hydroxy-fasudil reversed ET-1-induced vasoconstriction with an IC50 of 3, 15, and 111 μmol/L, respectively. DbcAMP stimulated a dose-dependent vasodilation (Ec50 = 1 mmol/L and a reduction of [Ca2+]i (EC50 = 0.3 μmol/L of ET-1-preconstricted vessels (1 nmol/L. Fasudil and dbcAMP both reversed the ET-1-induced increase in Ca2+ sensitivity. Conclusion Rho-kinase inhibition and dbcAMP reversed ET-1-induced vasoconstriction and Ca2+-sensitization. Therefore, Rho-kinase inhibitors or cAMP modulators could possess promise as pharmacological tools for the treatment of ET-1-induced constriction, ischemic stroke and sudden hearing loss.

  12. Erythropoietin Modulates Autophagy Signaling in the Developing Rat Brain in an In Vivo Model of Oxygen-Toxicity

    Directory of Open Access Journals (Sweden)

    Marco Sifringer

    2012-10-01

    Full Text Available Autophagy is a self-degradative process that involves turnover and recycling of cytoplasmic components in healthy and diseased tissue. Autophagy has been shown to be protective at the early stages of programmed cell death but it can also promote apoptosis under certain conditions. Earlier we demonstrated that oxygen contributes to the pathogenesis of neonatal brain damage, which can be ameliorated by intervention with recombinant human erythropoietin (rhEpo. Extrinsic- and intrinsic apoptotic pathways are involved in oxygen induced neurotoxicity but the role of autophagy in this model is unclear. We analyzed the expression of autophagy activity markers in the immature rodent brain after exposure to elevated oxygen concentrations. We observed a hyperoxia-exposure dependent regulation of autophagy-related gene (Atg proteins Atg3, 5, 12, Beclin-1, microtubule-associated protein 1 light chain 3 (LC3, LC3A-II, and LC3B-II which are all key autophagy activity proteins. Interestingly, a single injection with rhEpo at the onset of hyperoxia counteracted these oxygen-mediated effects. Our results indicate that rhEpo generates its protective effect by modifying the key autophagy activity proteins.

  13. Newly synthesized bis-benzimidazole compound 8 induces apoptosis, autophagy and reactive oxygen species generation in HeLa cells.

    Science.gov (United States)

    Chu, Naying; Yao, Guodong; Liu, Yuan; Cheng, Maosheng; Ikejima, Takashi

    2016-09-01

    Compound 8 (C8) is a newly synthesized bis-benzimidazole derivative and exerts significant anti-tumor activity in vitro. Previous studies demonstrated that C8 induced apoptosis and autophagy in human promyelocytic leukemia HL60 cells. However, cytotoxicity study on human peripheral blood mononuclear cells (hPBMC) showed that C8 exhibited less toxicity in normal cells. In this study, the molecular mechanism of C8 on human cervical carcinoma HeLa cells was investigated. The results showed that C8 inhibited the growth of HeLa cells and triggered both apoptotic and autophagic cell death. Subsequent experiment also indicated that reactive oxygen species (ROS) generation was induced in C8-treated HeLa cells. Since ROS scavenger decreased the ratio of apoptotic and autophagic cells, ROS generation contributed to C8-induced apoptosis and autophagy. Furthermore, inhibitors of apoptosis and autophagy also reduced ROS generation, respectively. Autophagy inhibition increased cell growth compared to C8-treated group and attenuated apoptotic cell death, indicating that C8-induced autophagy promoted apoptosis for cell death. However, the percentage of autophagic cells was enhanced when limiting apoptosis process. Taken together, C8 induced ROS-mediated apoptosis and autophagy in HeLa cells, autophagy promoted apoptosis but the former was antagonized by the latter. The data also gave us a new perspective on the anti-tumor effect of C8. PMID:27497983

  14. The C/EBPbeta isoform, liver-inhibitory protein (LIP), induces autophagy in breast cancer cell lines

    International Nuclear Information System (INIS)

    Autophagy is a process involving the bulk degradation of cellular components in the cytoplasm via the lysosomal degradation pathway. Autophagy manifests a protective role in stressful conditions such as nutrient or growth factor depletion; however, extensive degradation of regulatory molecules or organelles essential for survival can lead to the demise of the cell, or autophagy-mediated cell death. The role of autophagy in cancer is complex with roles in both tumor suppression and tumor promotion proposed. Here we report that an isoform of the C/EBPbeta transcription factor, liver-enriched inhibitory protein (LIP), induces cell death in human breast cancer cells and stimulates autophagy. Overexpression of LIP is incompatible with cell growth and when cell cycle analysis was performed, a DNA profile of cells undergoing apoptosis was not observed. Instead, LIP expressing cells appeared to have large autophagic vesicles when examined via electron microscopy. Autophagy was further assessed in LIP expressing cells by monitoring the development of acidic vesicular organelles and conversion of LC3 from the cytoplasmic form to the membrane-bound form. Our work shows that C/EBPbeta isoform, LIP, is another member of the group of transcription factors, including E2F1 and p53, which are capable of playing a role in autophagy.

  15. The role of autophagy in Parkinson's disease

    Institute of Scientific and Technical Information of China (English)

    Lei Zhang; Yaru Dong; Xiaoheng Xu; Zhong Xu

    2012-01-01

    Although Parkinson's disease is the most common neurodegenerative movement disorder, the mechanisms of pathogenesis remain poorly understood. Recent findings have shown that deregulation of the autophagy-lysosome pathway is involved in the pathogenesis of Parkinson's disease. This review summarizes the most recent findings and discusses the unique role of the autophagy-lysosome pathway in Parkinson's disease to highlight the possibility of Parkinson's disease treatment strategies that incorporate autophagy-lysosome pathway modulation.

  16. Oxidative Stress and Autophagy in Cardiovascular Homeostasis

    OpenAIRE

    Morales, Cyndi R.; Pedrozo, Zully; Lavandero, Sergio; Hill, Joseph A.

    2014-01-01

    Significance: Autophagy is an evolutionarily ancient process of intracellular protein and organelle recycling required to maintain cellular homeostasis in the face of a wide variety of stresses. Dysregulation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) leads to oxidative damage. Both autophagy and ROS/RNS serve pathological or adaptive roles within cardiomyocytes, depending on the context. Recent Advances: ROS/RNS and autophagy communicate with each other via both tra...

  17. Autophagy and oxidative stress in cardiovascular diseases

    OpenAIRE

    Mei, Yu; Thompson, Melissa D.; Cohen, Richard A.; Tong, XiaoYong

    2014-01-01

    Autophagy is a highly conserved degradation process by which intracellular components, including soluble macromolecules (e.g. nucleic acids, proteins, carbohydrates, and lipids) and dysfunctional organelles (e.g. mitochondria, ribosomes, peroxisomes, and endoplasmic reticulum) are degraded by the lysosome. Autophagy is orchestrated by the autophagy related protein (Atg) composed protein complexes to form autophagosomes, which fuse with lysosomes to generate autolysosomes where the contents ar...

  18. Modulating autophagy: a strategy for cancer therapy

    Institute of Scientific and Technical Information of China (English)

    Jun-Lin Li; Shao-Liang Han; Xia Fan

    2011-01-01

    Autophagy is a process in which long-lived proteins,damaged cell organelles,and other cellular particles are sequestered and degraded.This process is important for maintaining the cellular microenvironment when the cell is under stress.Many studies have shown that autophagy plays a complex role in human diseases,especially in cancer,where it is known to have paradoxical effects.Namely,autophagy provides the energy for metabolism and tumor growth and leads to cell death that promotes tumor suppression.The link between autophagy and cancer is also evident in that some of the genes that regulate carcinogenesis,oncogenes and tumor suppressor genes,participate in or impact the autophagy process.Therefore,modulating autophagy will be a valuable topic for cancer therapy.Many studies have shown that autophagy can inhibit the tumor growth when autophagy modulators are combined with radiotherapy and/or chemotherapy.These findings suggest that autophagy may be a potent target for cancer therapy.

  19. Involvement of Autophagy in Coronavirus Replication

    Directory of Open Access Journals (Sweden)

    Paul Britton

    2012-11-01

    Full Text Available Coronaviruses are single stranded, positive sense RNA viruses, which induce the rearrangement of cellular membranes upon infection of a host cell. This provides the virus with a platform for the assembly of viral replication complexes, improving efficiency of RNA synthesis. The membranes observed in coronavirus infected cells include double membrane vesicles. By nature of their double membrane, these vesicles resemble cellular autophagosomes, generated during the cellular autophagy pathway. In addition, coronavirus infection has been demonstrated to induce autophagy. Here we review current knowledge of coronavirus induced membrane rearrangements and the involvement of autophagy or autophagy protein microtubule associated protein 1B light chain 3 (LC3 in coronavirus replication.

  20. Principles of Safety Pharmacology

    OpenAIRE

    Pugsley, M. K.; Authier, S; Curtis, M J

    2008-01-01

    Safety Pharmacology is a rapidly developing discipline that uses the basic principles of pharmacology in a regulatory-driven process to generate data to inform risk/benefit assessment. The aim of Safety Pharmacology is to characterize the pharmacodynamic/pharmacokinetic (PK/PD) relationship of a drug's adverse effects using continuously evolving methodology. Unlike toxicology, Safety Pharmacology includes within its remit a regulatory requirement to predict the risk of rare lethal events. Thi...

  1. Autophagy, Innate Immunity and Tissue Repair in Acute Kidney Injury

    Science.gov (United States)

    Duann, Pu; Lianos, Elias A.; Ma, Jianjie; Lin, Pei-Hui

    2016-01-01

    Kidney is a vital organ with high energy demands to actively maintain plasma hemodynamics, electrolytes and water homeostasis. Among the nephron segments, the renal tubular epithelium is endowed with high mitochondria density for their function in active transport. Acute kidney injury (AKI) is an important clinical syndrome and a global public health issue with high mortality rate and socioeconomic burden due to lack of effective therapy. AKI results in acute cell death and necrosis of renal tubule epithelial cells accompanied with leakage of tubular fluid and inflammation. The inflammatory immune response triggered by the tubular cell death, mitochondrial damage, associative oxidative stress, and the release of many tissue damage factors have been identified as key elements driving the pathophysiology of AKI. Autophagy, the cellular mechanism that removes damaged organelles via lysosome-mediated degradation, had been proposed to be renoprotective. An in-depth understanding of the intricate interplay between autophagy and innate immune response, and their roles in AKI pathology could lead to novel therapies in AKI. This review addresses the current pathophysiology of AKI in aspects of mitochondrial dysfunction, innate immunity, and molecular mechanisms of autophagy. Recent advances in renal tissue regeneration and potential therapeutic interventions are also discussed. PMID:27153058

  2. Macrophage migration inhibitory factor induces vascular leakage via autophagy

    Directory of Open Access Journals (Sweden)

    Hong-Ru Chen

    2015-01-01

    Full Text Available Vascular leakage is an important feature of acute inflammatory shock, which currently has no effective treatment. Macrophage migration inhibitory factor (MIF is a pro-inflammatory cytokine that can induce vascular leakage and plays an important role in the pathogenesis of shock. However, the mechanism of MIF-induced vascular leakage is still unclear. In this study, using recombinant MIF (rMIF, we demonstrated that MIF induced disorganization and degradation of junction proteins and increased the permeability of human endothelial cells in vitro. Western blotting analysis showed that rMIF treatment induced LC3 conversion and p62 degradation. Inhibition of autophagy with a PI3K inhibitor (3-MA, a ROS scavenger (NAC or autophagosomal-lysosomal fusion inhibitors (bafilomycin A1 and chloroquine rescued rMIF-induced vascular leakage, suggesting that autophagy mediates MIF-induced vascular leakage. The potential involvement of other signaling pathways was also studied using different inhibitors, and the results suggested that MIF-induced vascular leakage may occur through the ERK pathway. In conclusion, we showed that MIF triggered autophagic degradation of endothelial cells, resulting in vascular leakage. Inhibition of MIF-induced autophagy may provide therapeutic targets against vascular leakage in inflammatory shock.

  3. Autophagy, Innate Immunity and Tissue Repair in Acute Kidney Injury

    Directory of Open Access Journals (Sweden)

    Pu Duann

    2016-05-01

    Full Text Available Kidney is a vital organ with high energy demands to actively maintain plasma hemodynamics, electrolytes and water homeostasis. Among the nephron segments, the renal tubular epithelium is endowed with high mitochondria density for their function in active transport. Acute kidney injury (AKI is an important clinical syndrome and a global public health issue with high mortality rate and socioeconomic burden due to lack of effective therapy. AKI results in acute cell death and necrosis of renal tubule epithelial cells accompanied with leakage of tubular fluid and inflammation. The inflammatory immune response triggered by the tubular cell death, mitochondrial damage, associative oxidative stress, and the release of many tissue damage factors have been identified as key elements driving the pathophysiology of AKI. Autophagy, the cellular mechanism that removes damaged organelles via lysosome-mediated degradation, had been proposed to be renoprotective. An in-depth understanding of the intricate interplay between autophagy and innate immune response, and their roles in AKI pathology could lead to novel therapies in AKI. This review addresses the current pathophysiology of AKI in aspects of mitochondrial dysfunction, innate immunity, and molecular mechanisms of autophagy. Recent advances in renal tissue regeneration and potential therapeutic interventions are also discussed.

  4. Legionella pneumophila restrains autophagy by modulating the host's sphingolipid metabolism.

    Science.gov (United States)

    Rolando, Monica; Escoll, Pedro; Buchrieser, Carmen

    2016-06-01

    Sphingolipids are bioactive molecules playing a key role as membrane components, but they are also central regulators of many intracellular processes including macroautophagy/autophagy. In particular, sphingosine-1-phosphate (S1P) is a critical mediator that controls the balance between sphingolipid-induced autophagy and cell death. S1P levels are adjusted via S1P synthesis, dephosphorylation or degradation, catalyzed by SGPL1 (sphingosine-1-phosphate lyase 1). Intracellular pathogens are able to modulate many different host cell pathways to allow their replication. We have found that infection of eukaryotic cells with the human pathogen Legionella pneumophila triggers a change in the host cell sphingolipid metabolism and specifically affects the levels of sphingosine. Indeed, L. pneumophila secretes a protein highly homologous to eukaryotic SGPL1 (named LpSPL). We solved the crystal structure of LpSPL and showed that it encodes lyase activity, targets the host's sphingolipid metabolism, and plays a role in starvation-induced autophagy during L. pneumophila infection to promote intracellular survival. PMID:27191778

  5. Dehydroandrographolide, an iNOS inhibitor, extracted from Andrographis paniculata (Burm.f.) Nees, induces autophagy in human oral cancer cells.

    Science.gov (United States)

    Hsieh, Ming-Ju; Lin, Chiao-Wen; Chiou, Hui-Ling; Yang, Shun-Fa; Chen, Mu-Kuan

    2015-10-13

    Autophagy, which is constitutively executed at the basal level in all cells, promotes cellular homeostasis by regulating the turnover of organelles and proteins. Andrographolide and dehydroandrographolide (DA) are the two principle components of Andrographis paniculata (Burm.f.) Nees. and are the main contributors to its therapeutic properties. However, the pharmacological activities of dehydroandrographolide (DA) remain unclear. In this study, DA induces oral cancer cell death by activating autophagy. Treatment with autophagy inhibitors inhibited DA-induced human oral cancer cell death. In addition, DA increased LC3-II expression and reduced p53 expression in a time- and concentration-dependent manner. Furthermore, DA induced autophagy and decreased cell viability through modulation of p53 expression. DA-induced autophagy was triggered by an activation of JNK1/2 and an inhibition of Akt and p38. In conclusion, this study demonstrated that DA induced autophagy in human oral cancer cells by modulating p53 expression, activating JNK1/2, and inhibiting Akt and p38. Finally, an administration of DA effectively suppressed the tumor formation in the oral carcinoma xenograft model in vivo. This is the first study to reveal the novel function of DA in activating autophagy, suggesting that DA could serve as a new and potential chemopreventive agent for treating human oral cancer. PMID:26356821

  6. Coffee induces autophagy in vivo

    OpenAIRE

    Pietrocola, Federico; Malik, Shoaib Ahmad; Mariño, Guillermo; Vacchelli, Erika; Senovilla, Laura; Chaba, Kariman; Niso-Santano, Mireia; Maiuri, Maria Chiara; Madeo, Frank; Kroemer, Guido

    2014-01-01

    Epidemiological studies and clinical trials revealed that chronic consumption coffee is associated with the inhibition of several metabolic diseases as well as reduction in overall and cause-specific mortality. We show that both natural and decaffeinated brands of coffee similarly rapidly trigger autophagy in mice. One to 4 h after coffee consumption, we observed an increase in autophagic flux in all investigated organs (liver, muscle, heart) in vivo, as indicated by the increased lipidation ...

  7. Combination treatment with fasudil and clioquinol produces synergistic anti-tumor effects in U87 glioblastoma cells by activating apoptosis and autophagy.

    Science.gov (United States)

    He, Mingliang; Luo, Ming; Liu, Qingyu; Chen, Jingkao; Li, Kaishu; Zheng, Meiguang; Weng, Yinlun; Ouyang, Leping; Liu, Anmin

    2016-04-01

    Survival of patients with glioblastoma (GBM) remains poor, and novel treatment methods are urgently needed. In this study, we tested the effects of a combination of fasudil, a ROCK inhibitor, and clioquinol, an 8-hydroxyquinoline derivative with antimicrobial properties, on human GBM U87 cells. Combination treatment synergistically inhibited the viability of glioma cells but not mouse normal neuron HT22 cells and significantly induced mitochondria-mediated apoptosis. Moreover, the combination was also found to trigger macro-autophagy (henceforth referred to as autophagy) by increasing the expression levels of several proteins involved in the induction of autophagy. Further studies showed that 3-methyladenine (3-MA) or chloroquine (CQ), two autophagy inhibitors, abrogated the cytotoxic effects of the combination treatment as well as the autophagy. Overall, we demonstrated that fasudil and clioquinol show synergistic anti-cancer effects, providing evidence for the further development of combination therapy for GBM. PMID:26725099

  8. Autophagy selectivity through receptor clustering

    Science.gov (United States)

    Rutenberg, Andrew; Brown, Aidan

    Substrate selectivity in autophagy requires an all-or-none cellular response. We focus on peroxisomes, for which autophagy receptor proteins NBR1 and p62 are well characterized. Using computational models, we explore the hypothesis that physical clustering of autophagy receptor proteins on the peroxisome surface provides an appropriate all-or-none response. We find that larger peroxisomes nucleate NBR1 clusters first, and lose them due to competitive coarsening last, resulting in significant size-selectivity. We then consider a secondary hypothesis that p62 inhibits NBR1 cluster formation. We find that p62 inhibition enhances size-selectivity enough that, even if there is no change of the pexophagy rate, the volume of remaining peroxisomes can significantly decrease. We find that enhanced ubiquitin levels suppress size-selectivity, and that this effect is more pronounced for individual peroxisomes. Sufficient ubiquitin allows receptor clusters to form on even the smallest peroxisomes. We conclude that NBR1 cluster formation provides a viable physical mechanism for all-or-none substrate selectivity in pexophagy. We predict that cluster formation is associated with significant size-selectivity. Now at Simon Fraser University.

  9. Autophagy and the (prorenin receptor

    Directory of Open Access Journals (Sweden)

    KatrinaJeanBinger

    2013-10-01

    Full Text Available The (prorenin receptor (PRR is a newly reported member of the renin-angiotensin system (RAS; a hormonal cascade responsible for regulating blood pressure. Originally, the identification of PRR was heralded as the next drug target of the RAS, of which such therapies would have increased benefits against target-organ damage and hypertension. However, in the years since its discovery several conditional knockout mouse models of PRR have demonstrated an essential role for this receptor unrelated to the renin-angiotensin system and blood pressure. Deletion of PRR in podocytes or cardiomyocytes resulted in the rapid onset of organ failure, eventuating in animal mortality after only a matter of weeks. In both cases, deletion of PRR resulted in the intracellular accumulation of autophagosomes and misfolded proteins, indicating a disturbance in autophagy. In light of the fact that the majority of PRR is located intracellularly, this molecular function appears to be more relevant than its ability to bind to high, non-physiological concentrations of (prorenin. This review will focus on the role of PRR in autophagy and its importance in maintaining cellular homeostasis. Understanding the link between PRR, autophagy and how its loss results in cell death will be essential for deciphering its role in physiology and pathology.

  10. Noncoding RNA blockade of autophagy is therapeutic in medullary thyroid cancer

    International Nuclear Information System (INIS)

    Micro-RNAs are dysregulated in medullary thyroid carcinoma (MTC) and preliminary studies have shown that miRNAs may enact a therapeutic effect through changes in autophagic flux. Our aim was to study the in vitro effect of miR-9-3p on MTC cell viability, autophagy and to investigate the mRNA autophagy gene profile of sporadic versus hereditary MTC. The therapeutic role of miR-9-3p was investigated in vitro using human MTC cell lines (TT and MZ-CRC-1 cells), cell viability assays, and functional mechanism studies with a focus on cell cycle, apoptosis, and autophagy. Post-miR-9-3p transfection mRNA profiling of cell lines was performed using a customized, quantitative RT-PCR gene array card. This card was also run on clinical tumor samples (sporadic: n = 6; hereditary: n = 6) and correlated with clinical data. Mir-9-3p transfection resulted in reduced in vitro cell viability; an effect mediated through autophagy inhibition. This was accompanied by evidence of G2 arrest in the TT cell line and increased apoptosis in both cell lines. Atg5 was validated as a predicted miR-9-3p mRNA target in TT cells. Post-miR-9-3p transfection array studies showed a significant global decline in autophagy gene expression (most notably in PIK3C3, mTOR, and LAMP-1). Autophagy gene mRNAs were generally overexpressed in sporadic (vs. hereditary MTC) and Beclin-1 overexpression was shown to correlate with residual disease. Autophagy is a tumor cell survival mechanism in MTC that when disabled, is of therapeutic advantage. Beclin-1 expression may be a useful prognostic biomarker of aggressive disease

  11. Mevalonate cascade regulation of airway mesenchymal cell autophagy and apoptosis: a dual role for p53.

    Directory of Open Access Journals (Sweden)

    Saeid Ghavami

    Full Text Available Statins inhibit the proximal steps of cholesterol biosynthesis, and are linked to health benefits in various conditions, including cancer and lung disease. We have previously investigated apoptotic pathways triggered by statins in airway mesenchymal cells, and identified reduced prenylation of small GTPases as a primary effector mechanism leading to p53-mediated cell death. Here, we extend our studies of statin-induced cell death by assessing endpoints of both apoptosis and autophagy, and investigating their interplay and coincident regulation. Using primary cultured human airway smooth muscle (HASM and human airway fibroblasts (HAF, autophagy, and autophagosome formation and flux were assessed by transmission electron microscopy, cytochemistry (lysosome number and co-localization with LC3 and immunoblotting (LC3 lipidation and Atg12-5 complex formation. Chemical inhibition of autophagy increased simvastatin-induced caspase activation and cell death. Similarly, Atg5 silencing with shRNA, thus preventing Atg5-12 complex formation, increased pro-apoptotic effects of simvastatin. Simvastatin concomitantly increased p53-dependent expression of p53 up-regulated modulator of apoptosis (PUMA, NOXA, and damage-regulated autophagy modulator (DRAM. Notably both mevalonate cascade inhibition-induced autophagy and apoptosis were p53 dependent: simvastatin increased nuclear p53 accumulation, and both cyclic pifithrin-α and p53 shRNAi partially inhibited NOXA, PUMA expression and caspase-3/7 cleavage (apoptosis and DRAM expression, Atg5-12 complex formation, LC3 lipidation, and autophagosome formation (autophagy. Furthermore, the autophagy response is induced rapidly, significantly delaying apoptosis, suggesting the existence of a temporally coordinated p53 regulation network. These findings are relevant for the development of statin-based therapeutic approaches in obstructive airway disease.

  12. The role of autophagy in sensitizing malignant glioma cells to radiation therapy

    Institute of Scientific and Technical Information of China (English)

    Wenzhuo Zhuang; Zhenghong Qin; Zhongqin Liang

    2009-01-01

    Malignant gliomas representthe majority of primary brain tumors.The current standard treatments for malignant gliomas include surgical resection,radiation therapy,and chemotherapy.Radiotherapy,a standard adjuvant therapy,confers some survival advantages,but resistance of the glioma cells to the efficacy of radiation limits the success of the treatment.The mechanisms underlying glioma cell radioresistance have remained elusive.Autophagy is a protein degradation system characterized by a prominent formation of double-membrane vesicles in the cytoplasm.Recent studies suggest that autophagy may be important in the regulation of cancer development and progression and in determining the response of tumor cells to anticancer therapy.Also,autophagy is a novel response of glioma cells to ionizing radiation.Autophagic cell death is considered programmed cell death type Ⅱ,whereas apoptosis is programmed cell death type Ⅰ.These two types of cell death are predominantly distinctive,but many studies demonstrate a cross-talk between them.Whether autophagy in cancer cells causes death or protects cells is controversial.The regulatory pathways of autophagy share several molecules.P13K/Akt/Mtor,DNA-PK,tumor suppressor genes, mitochondrial damage,and lysosome may play important roles in radiation-induced autophagy in glioma cells.Recently,a highly tumorigenic glioma tumor subpopulation,termed cancer stem cell or tumor-initiating cell,has been shown to promote therapeutic resistance.This review summarizes the main mediators associated with radiation-induced autophagy in malignant glioma cells and discusses the implications of the cancer stem cell hypothesis for the development of future therapies for brain tumors.

  13. A genetic screen for modifiers of Drosophila caspase Dcp-1 reveals caspase involvement in autophagy and novel caspase-related genes

    Directory of Open Access Journals (Sweden)

    Ahnn Joohong

    2010-01-01

    Full Text Available Abstract Background Caspases are cysteine proteases with essential functions in the apoptotic pathway; their proteolytic activity toward various substrates is associated with the morphological changes of cells. Recent reports have described non-apoptotic functions of caspases, including autophagy. In this report, we searched for novel modifiers of the phenotype of Dcp-1 gain-of-function (GF animals by screening promoter element- inserted Drosophila melanogaster lines (EP lines. Results We screened ~15,000 EP lines and identified 72 Dcp-1-interacting genes that were classified into 10 groups based on their functions and pathways: 4 apoptosis signaling genes, 10 autophagy genes, 5 insulin/IGF and TOR signaling pathway genes, 6 MAP kinase and JNK signaling pathway genes, 4 ecdysone signaling genes, 6 ubiquitination genes, 11 various developmental signaling genes, 12 transcription factors, 3 translation factors, and 11 other unclassified genes including 5 functionally undefined genes. Among them, insulin/IGF and TOR signaling pathway, MAP kinase and JNK signaling pathway, and ecdysone signaling are known to be involved in autophagy. Together with the identification of autophagy genes, the results of our screen suggest that autophagy counteracts Dcp-1-induced apoptosis. Consistent with this idea, we show that expression of eGFP-Atg5 rescued the eye phenotype caused by Dcp-1 GF. Paradoxically, we found that over-expression of full-length Dcp-1 induced autophagy, as Atg8b-GFP, an indicator of autophagy, was increased in the eye imaginal discs and in the S2 cell line. Taken together, these data suggest that autophagy suppresses Dcp-1-mediated apoptotic cell death, whereas Dcp-1 positively regulates autophagy, possibly through feedback regulation. Conclusions We identified a number of Dcp-1 modifiers that genetically interact with Dcp-1-induced cell death. Our results showing that Dcp-1 and autophagy-related genes influence each other will aid future

  14. Rapamycin requires AMPK activity and p27 expression for promoting autophagy-dependent Tsc2-null cell survival.

    Science.gov (United States)

    Campos, Tania; Ziehe, Javiera; Fuentes-Villalobos, Francisco; Riquelme, Orlando; Peña, Daniela; Troncoso, Rodrigo; Lavandero, Sergio; Morin, Violeta; Pincheira, Roxana; Castro, Ariel F

    2016-06-01

    Tuberous sclerosis complex (TSC) disease results from inactivation of the TSC1 or TSC2 gene, and is characterized by benign tumors in several organs. Because TSC tumorigenesis correlates with hyperactivation of mTORC1, current therapies focus on mTORC1 inhibition with rapamycin or its analogs. Rapamycin-induced tumor shrinkage has been reported, but tumor recurrence occurs on withdrawal from rapamycin. Autophagy has been associated with development of TSC tumors and with tumor cell survival during rapamycin treatment. mTORC1 and AMPK directly inhibit and activate autophagy, respectively. AMPK is hyperactivated in TSC cells and tumors, and drives cytoplasmic sequestration of the cell-cycle inhibitor p27KIP (p27). Whether AMPK and p27 are involved in rapamycin-induced autophagy and survival of TSC cells remain unexplored. Here, we show that inhibition of AMPK by compound C or by shRNA-mediated depletion of LKB1 reduces activation of autophagy by rapamycin in Tsc2-null cells. Similarly, shRNA-mediated depletion of p27 inhibited rapamycin-induced autophagy. In support of p27 lying downstream of AMPK on the activation of autophagy in Tsc2-null cells, a p27 mutant that preferentially localizes in the cytosol recovered the effect of rapamycin on autophagy in both p27- and LKB1-depleted cells, but a nuclear p27 mutant was inactive. Finally, we show that p27-dependent activation of autophagy is involved in Tsc2-null cell survival under rapamycin treatment. These results indicate that an AMPK/p27 axis is promoting a survival mechanism that could explain in part the relapse of TSC tumors treated with rapamycin, exposing new avenues for designing more efficient treatments for TSC patients. PMID:26975583

  15. Characterization of the autophagy marker protein Atg8 reveals atypical features of autophagy in Plasmodium falciparum.

    Directory of Open Access Journals (Sweden)

    Rahul Navale

    Full Text Available Conventional autophagy is a lysosome-dependent degradation process that has crucial homeostatic and regulatory functions in eukaryotic organisms. As malaria parasites must dispose a number of self and host cellular contents, we investigated if autophagy in malaria parasites is similar to the conventional autophagy. Genome wide analysis revealed a partial autophagy repertoire in Plasmodium, as homologs for only 15 of the 33 yeast autophagy proteins could be identified, including the autophagy marker Atg8. To gain insights into autophagy in malaria parasites, we investigated Plasmodium falciparum Atg8 (PfAtg8 employing techniques and conditions that are routinely used to study autophagy. Atg8 was similarly expressed and showed punctate localization throughout the parasite in both asexual and sexual stages; it was exclusively found in the pellet fraction as an integral membrane protein, which is in contrast to the yeast or mammalian Atg8 that is distributed among cytosolic and membrane fractions, and suggests for a constitutive autophagy. Starvation, the best known autophagy inducer, decreased PfAtg8 level by almost 3-fold compared to the normally growing parasites. Neither the Atg8-associated puncta nor the Atg8 expression level was significantly altered by treatment of parasites with routinely used autophagy inhibitors (cysteine (E64 and aspartic (pepstatin protease inhibitors, the kinase inhibitor 3-methyladenine, and the lysosomotropic agent chloroquine, indicating an atypical feature of autophagy. Furthermore, prolonged inhibition of the major food vacuole protease activity by E64 and pepstatin did not cause accumulation of the Atg8-associated puncta in the food vacuole, suggesting that autophagy is primarily not meant for degradative function in malaria parasites. Atg8 showed partial colocalization with the apicoplast; doxycycline treatment, which disrupts apicoplast, did not affect Atg8 localization, suggesting a role, but not exclusive, in

  16. Autophagy-associated dengue vesicles promote viral transmission avoiding antibody neutralization.

    Science.gov (United States)

    Wu, Yan-Wei; Mettling, Clément; Wu, Shang-Rung; Yu, Chia-Yi; Perng, Guey-Chuen; Lin, Yee-Shin; Lin, Yea-Lih

    2016-01-01

    One of the major defense mechanisms against virus spread in vivo is the blocking of viral infectibility by neutralizing antibodies. We describe here the identification of infectious autophagy-associated dengue vesicles released from infected cells. These vesicles contain viral proteins E, NS1, prM/M, and viral RNA, as well as host lipid droplets and LC3-II, an autophagy marker. The viral RNA can be protected within the autophagic organelles since anti-dengue neutralizing antibodies do not have an effect on the vesicle-mediated transmission that is able to initiate a new round of infection in target cells. Importantly, such infectious vesicles were also detected in a patient serum. Our study suggests that autophagy machinery plays a new role in dengue virus transmission. This discovery explains the inefficiency of neutralizing antibody upon dengue infection as a potential immune evasion mechanism in vivo. PMID:27558165

  17. Reactive oxygen species are involved in insulin-dependent regulation of autophagy in primary rat podocytes.

    Science.gov (United States)

    Audzeyenka, Irena; Rogacka, Dorota; Piwkowska, Agnieszka; Rychlowski, Michal; Bierla, Joanna Beata; Czarnowska, Elżbieta; Angielski, Stefan; Jankowski, Maciej

    2016-06-01

    Autophagy is an intracellular defense mechanism responsible for the turnover of damaged or non-functional cellular constituents. This process provides cells with energy and essential compounds under unfavorable environmental conditions-such as oxidative stress and hyperglycemia, which are both observed in diabetes. The most common diabetes complication is diabetic nephropathy (DN), which can lead to renal failure. This condition often includes impaired podocyte function. Here we investigated autophagic activity in rat podocytes cultured with a high insulin concentration (300nM). Autophagy was activated after 60min of insulin stimulation. Moreover, this effect was abolished following pharmacological (apocynin) or genetic (siRNA) inhibition of NAD(P)H oxidase activity, indicating that insulin-dependent autophagy stimulation involved reactive oxygen species (ROS). We also observed a continuous and time-dependent increase of podocyte albumin permeability in response to insulin, and this process was slightly improved by autophagy inhibition following short-term insulin exposure. Our results suggest that insulin may be a factor affecting the development of diabetic nephropathy. PMID:27026581

  18. Regulation of autophagy in human skeletal muscle: effects of exercise, exercise training and insulin stimulation

    DEFF Research Database (Denmark)

    Fritzen, Andreas Mæchel; Madsen, Agnete Louise Bjerregaard; Kleinert, Maximilian;

    2016-01-01

    Studies in rodent muscle suggest that autophagy is regulated by acute exercise, exercise training and insulin stimulation. However, little is known about the regulation of autophagy in human skeletal muscle. Here we investigate the autophagic response to acute one-legged exercise, one-legged exer......Studies in rodent muscle suggest that autophagy is regulated by acute exercise, exercise training and insulin stimulation. However, little is known about the regulation of autophagy in human skeletal muscle. Here we investigate the autophagic response to acute one-legged exercise, one......-legged exercise training as well as in response to subsequent insulin stimulation in exercised and non-exercised human muscle. Acute one-legged exercise decreased (p<0.01) lipidation of LC3 (∼50 %) and the LC3-II/LC3-I ratio (∼60 %) indicating that content of autophagosomes decreases with exercise in human muscle....... The decrease in LC3-II/LC3-I ratio did not correlate with activation of AMPK trimer complexes in human muscle. Consistently, pharmacological AMPK activation with AICAR in mouse muscle did not affect the LC3-II/LC3-I ratio. Four hours after exercise, insulin further reduced (p<0.01) the LC3-II/LC3-I...

  19. MCOLN1 is a ROS sensor in lysosomes that regulates autophagy

    Science.gov (United States)

    Zhang, Xiaoli; Cheng, Xiping; Yu, Lu; Yang, Junsheng; Calvo, Raul; Patnaik, Samarjit; Hu, Xin; Gao, Qiong; Yang, Meimei; Lawas, Maria; Delling, Markus; Marugan, Juan; Ferrer, Marc; Xu, Haoxing

    2016-01-01

    Cellular stresses trigger autophagy to remove damaged macromolecules and organelles. Lysosomes ‘host' multiple stress-sensing mechanisms that trigger the coordinated biogenesis of autophagosomes and lysosomes. For example, transcription factor (TF)EB, which regulates autophagy and lysosome biogenesis, is activated following the inhibition of mTOR, a lysosome-localized nutrient sensor. Here we show that reactive oxygen species (ROS) activate TFEB via a lysosomal Ca2+-dependent mechanism independent of mTOR. Exogenous oxidants or increasing mitochondrial ROS levels directly and specifically activate lysosomal TRPML1 channels, inducing lysosomal Ca2+ release. This activation triggers calcineurin-dependent TFEB-nuclear translocation, autophagy induction and lysosome biogenesis. When TRPML1 is genetically inactivated or pharmacologically inhibited, clearance of damaged mitochondria and removal of excess ROS are blocked. Furthermore, TRPML1's ROS sensitivity is specifically required for lysosome adaptation to mitochondrial damage. Hence, TRPML1 is a ROS sensor localized on the lysosomal membrane that orchestrates an autophagy-dependent negative-feedback programme to mitigate oxidative stress in the cell. PMID:27357649

  20. Autophagy- An emerging target for melanoma therapy.

    Science.gov (United States)

    Ndoye, Abibatou; Weeraratna, Ashani T

    2016-01-01

    Melanoma accounts for only 5% of all cancers but is the leading cause of skin cancer death due to its high metastatic potential. Patients with metastatic melanoma have a 10-year survival rate of less than 10%. While the clinical landscape for melanoma is evolving rapidly, lack of response to therapies, as well as resistance to therapy remain critical obstacles for treatment of this disease. In recent years, a myriad of therapy resistance mechanisms have been unravelled, one of which is autophagy, the focus of this review. In advanced stages of malignancy, melanoma cells hijack the autophagy machinery in order to alleviate drug-induced and metabolic stress in the tumor microenvironment, thereby promoting resistance to multiple therapies, tumor cell survival, and progression.  Autophagy is an essential cellular process that maintains cellular homeostasis through the recycling of intracellular constituents. Early studies on the role of autophagy in cancer generated controversy as to whether autophagy was pro- or anti-tumorigenic. Currently, there is a consensus that autophagy is tumor-suppressive in the early stages of cancer and tumor-promoting in established tumors.  This review aims to highlight current understandings on the role of autophagy in melanoma malignancy, and specifically therapy resistance; as well as to evaluate recent strategies for therapeutic autophagy modulation. PMID:27583134

  1. Tumor Suppression and Promotion by Autophagy

    Directory of Open Access Journals (Sweden)

    Yenniffer Ávalos

    2014-01-01

    Full Text Available Autophagy is a highly regulated catabolic process that involves lysosomal degradation of proteins and organelles, mostly mitochondria, for the maintenance of cellular homeostasis and reduction of metabolic stress. Problems in the execution of this process are linked to different pathological conditions, such as neurodegeneration, aging, and cancer. Many of the proteins that regulate autophagy are either oncogenes or tumor suppressor proteins. Specifically, tumor suppressor genes that negatively regulate mTOR, such as PTEN, AMPK, LKB1, and TSC1/2 stimulate autophagy while, conversely, oncogenes that activate mTOR, such as class I PI3K, Ras, Rheb, and AKT, inhibit autophagy, suggesting that autophagy is a tumor suppressor mechanism. Consistent with this hypothesis, the inhibition of autophagy promotes oxidative stress, genomic instability, and tumorigenesis. Nevertheless, autophagy also functions as a cytoprotective mechanism under stress conditions, including hypoxia and nutrient starvation, that promotes tumor growth and resistance to chemotherapy in established tumors. Here, in this brief review, we will focus the discussion on this ambiguous role of autophagy in the development and progression of cancer.

  2. Autophagy in allografts rejection: A new direction?

    Science.gov (United States)

    Sun, Hukui; Cheng, Dayan; Ma, Yuanyuan; Wang, Huaiquan; Liang, Ting; Hou, Guihua

    2016-03-18

    Despite the introduction of new and effective immunosuppressive drugs, acute cellular graft rejection is still a major risk for graft survival. Modulating the dosage of immunosuppressive drugs is not a good choice for all patients, new rejection mechanisms discovery are crucial to limit the inflammatory process and preserve the function of the transplant. Autophagy, a fundamental cellular process, can be detected in all subsets of lymphocytes and freshly isolated naive T lymphocytes. It is required for the homeostasis and function of T lymphocytes, which lead to cell survival or cell death depending on the context. T cell receptor (TCR) stimulation and costimulator signals induce strong autophagy, and autophagy deficient T cells leads to rampant apoptosis upon TCR stimulation. Autophagy has been proved to be activated during ischemia-reperfusion (I/R) injury and associated with grafts dysfunction. Furthermore, Autophagy has also emerged as a key mechanism in orchestrating innate and adaptive immune response to self-antigens, which relates with negative selection and Foxp3(+) Treg induction. Although, the role of autophagy in allograft rejection is unknown, current data suggest that autophagy indeed sweeps across both in the graft organs and recipients lymphocytes after transplantation. This review presents the rationale for the hypothesis that targeting the autophagy pathway could be beneficial in promoting graft survival after transplantation. PMID:26876576

  3. Phosphoethanolamine Modification of Neisseria gonorrhoeae Lipid A Reduces Autophagy Flux in Macrophages.

    Directory of Open Access Journals (Sweden)

    Susu M Zughaier

    Full Text Available Autophagy, an ancient homeostasis mechanism for macromolecule degradation, performs an important role in host defense by facilitating pathogen elimination. To counteract this host defense strategy, bacterial pathogens have evolved a variety of mechanisms to avoid or otherwise dysregulate autophagy by phagocytic cells so as to enhance their survival during infection. Neisseria gonorrhoeae is a strictly human pathogen that causes the sexually transmitted infection, gonorrhea. Phosphoethanolamine (PEA addition to the 4' position of the lipid A (PEA-lipid A moiety of the lipooligosaccharide (LOS produced by gonococci performs a critical role in this pathogen's ability to evade innate defenses by conferring decreased susceptibility to cationic antimicrobial (or host-defense peptides, complement-mediated killing by human serum and intraleukocytic killing by human neutrophils compared to strains lacking this PEA decoration. Heretofore, however, it was not known if gonococci can evade autophagy and if so, whether PEA-lipid A contributes to this ability. Accordingly, by using murine macrophages and human macrophage-like phagocytic cell lines we investigated if PEA decoration of gonococcal lipid A modulates autophagy formation. We report that infection with PEA-lipid A-producing gonococci significantly reduced autophagy flux in murine and human macrophages and enhanced gonococcal survival during their association with macrophages compared to a PEA-deficient lipid A mutant. Our results provide further evidence that PEA-lipid A produced by gonococci is a critical component in the ability of this human pathogen to evade host defenses.

  4. Phosphoethanolamine Modification of Neisseria gonorrhoeae Lipid A Reduces Autophagy Flux in Macrophages.

    Science.gov (United States)

    Zughaier, Susu M; Kandler, Justin L; Balthazar, Jacqueline T; Shafer, William M

    2015-01-01

    Autophagy, an ancient homeostasis mechanism for macromolecule degradation, performs an important role in host defense by facilitating pathogen elimination. To counteract this host defense strategy, bacterial pathogens have evolved a variety of mechanisms to avoid or otherwise dysregulate autophagy by phagocytic cells so as to enhance their survival during infection. Neisseria gonorrhoeae is a strictly human pathogen that causes the sexually transmitted infection, gonorrhea. Phosphoethanolamine (PEA) addition to the 4' position of the lipid A (PEA-lipid A) moiety of the lipooligosaccharide (LOS) produced by gonococci performs a critical role in this pathogen's ability to evade innate defenses by conferring decreased susceptibility to cationic antimicrobial (or host-defense) peptides, complement-mediated killing by human serum and intraleukocytic killing by human neutrophils compared to strains lacking this PEA decoration. Heretofore, however, it was not known if gonococci can evade autophagy and if so, whether PEA-lipid A contributes to this ability. Accordingly, by using murine macrophages and human macrophage-like phagocytic cell lines we investigated if PEA decoration of gonococcal lipid A modulates autophagy formation. We report that infection with PEA-lipid A-producing gonococci significantly reduced autophagy flux in murine and human macrophages and enhanced gonococcal survival during their association with macrophages compared to a PEA-deficient lipid A mutant. Our results provide further evidence that PEA-lipid A produced by gonococci is a critical component in the ability of this human pathogen to evade host defenses. PMID:26641098

  5. Andrographolide radiosensitizes human ovarian cancer SKOV3 xenografts due to an enhanced apoptosis and autophagy.

    Science.gov (United States)

    Zhang, Chao; Qiu, Xingsheng

    2015-11-01

    Andrographolide (AND), a diterpenoid lactone isolated from Andrographis paniculata, has been shown to have radiosensitivity in several types of cancer. Whether AND can radiosensitize ovarian cancer remains unknown. The present study investigated the radiosensitizing effects of AND in human ovarian SKOV3 xenografts and examined the molecular mechanisms of AND-mediated radiosensitization. Nude mice bearing human ovarian SKOV3 were treated with AND to investigate the effects of drug administration on tumor growth, radiosensitivity, apoptosis, and autophagy. Subsequent Western blot analysis and monodansylcadaverine (MDC) staining (autophagy analysis) were used to determine the role of AND. Finally, the pathway of apoptosis was characterized by caspase-3 activity assay as well as TUNEL analysis. AND potently sensitized SKOV3 xenografts to radiation. Moreover, apoptosis and autophagy in radiation combined with drug-treated xenografts increased significantly compared with the simple drug or single radiation treatment. This result was associated with an increase in the Bax/Bcl-2 protein ratio and p-p53 expression after exposure to combination treatment. Meanwhile, the level of Beclin 1 and Atg5 and the conversion from LC3-I to LC3-II, three important proteins involved in autophagy, were increased. AND acts as a strong radiosensitizer in human ovarian SKOV3 xenografts in vivo by increasing the Bax/Bcl-2 protein ratio and promoting the activation of caspase-3, leading to enhanced apoptosis as well as autophagy. PMID:26014516

  6. Knockdown of WAVE1 enhances apoptosis of leukemia cells by downregulating autophagy.

    Science.gov (United States)

    Zhang, Zhaoxia; Wu, Benqing; Chai, Wenwen; Cao, Lizhi; Wang, Yangping; Yu, Yan; Yang, Liangchun

    2016-06-01

    Chemoresistance of leukemia constitutes a great challenge for successful treatment of leukemia. Autophagy has recently attracted increasing attention for its role in conferring resistance to various conventional anti-neoplastic regiments. In the present study, the authors showed that WAVE1, a member of WASP family verprolin-homologous proteins, is a critical regulator of chemoresistance during autophagy. It is positively correlated with clinical status in pediatric acute myeloblastic leukemia (AML) and leukemia cell lines. The knockdown of WAVE1 expression decreased autophagy was accompanied by an upregulation of autophagic marker microtubule-associated protein light chain 3 (LC3)-Ⅱ, a degradation of SQSTM1/sequestosome 1 (p62) and the formation of autophagosomes. Moreover, a suppression of WAVE1 expression increased the sensitivity of leukemia cells to chemotherapy and apoptosis, and depletion of WAVE1 expression promoted the translocation of Bcl-2 from mitochondria into the cytoplasm. In addition, a knockdown of PI3K-Ⅲ expression significantly inhibited WAVE1-mediated autophagy. Furthermore, suppression of WAVE1 expression blocked the interactions between Beclin1 and PI3K-Ⅲ and the disassociation of Beclin1-Bcl-2 during enhanced autophagy. The above results suggested that WAVE1 is a critical pro-autophagic protein capable of enhancing cell survival and regulating chemoresistance in leukemia cells potentially through the Beclin1/Bcl-2 and Beclin1/PI3K-Ⅲ complex-dependent pathways. PMID:27035872

  7. Beclin1-induced autophagy abrogates radioresistance of lung cancer cells by suppressing osteopontin

    International Nuclear Information System (INIS)

    Osteopontin (OPN) serves as an indicator of resistance to radiotherapy. However, the role of OPN in the development of acquired radioresistance in human lung cancer cells has not yet been fully elucidated. Therefore, the potential importance of OPN as a marker of lung cancer with a potential significant role in the development of radioresistance against repeated radiotherapy has prompted us to define the pathways by which OPN regulates lung cancer cell growth. In addition, autophagy has been reported to play a key role in the radiosensitization of cancer cells. Here, we report that increased OPN expression through induction of nuclear p53 following irradiation was inhibited by exogenous beclin-1 (BECN1). Our results clearly show that BECN1 gene expression led to induction of autophagy and inhibition of cancer cell growth and angiogenesis. Our results suggest that the induction of autophagy abrogated the radioresistance of the cancer cells. Interestingly, we showed that knockdown of OPN by lentivirus-mediated shRNA induced the autophagy of human lung cancer cell. Taken together, these results suggest that OPN and BECN1 can be molecular targets for overcoming radioresistance by controlling autophagy. (author)

  8. Inhibition of NF-κB promotes autophagy via JNK signaling pathway in porcine granulosa cells.

    Science.gov (United States)

    Gao, Hui; Lin, Lu; Haq, Ihtesham Ul; Zeng, Shen-Ming

    2016-04-22

    The transcription factor nuclear factor-κB (NF-κB) plays an important role in diverse processes, including cell proliferation and differentiation, apoptosis and inflammation. However, the role of NF-κB in porcine follicle development is not clearly elucidated. In this study, we demonstrated that follicle stimulating hormone (FSH) increased the level of inhibitor of NF-κB (IκB) protein and promoted the cytoplasmic localization of p65, indicating that FSH inhibits the activation of NF-κB in porcine granulosa cells. Moreover, inhibition of NF-κB by FSH or another specific inhibitor of NF-κB, pyrrolidine dithiocarbamate (PDTC), could activate JNK signaling and enhance autophagic activity in porcine granulosa cells. Knockdown of RelA (p65) Subunit of NF-κB by RNA interference abrogated the activation of JNK signaling pathway and the increase of autophagic protein expression by FSH. Meanwhile, the functional significance of FSH or PDTC-mediated autophagy were further investigated. Our results demonstrated that the increased autophagy promoted progesterone secretion in porcine granulosa cells. Blockage of autophagy by chloroquine obviated the FSH or PDTC-induced progesterone production. Taken together, these results indicate that inhibition of NF-κB increased autophagy via JNK signaling, and promote steroidogenesis in porcine granulosa cells. Our results provide new insights into the regulation and function of autophagy in mammalian follicle development. PMID:27016483

  9. Pharmacologic IKK/NF-κB inhibition causes antigen presenting cells to undergo TNFα dependent ROS-mediated programmed cell death

    Science.gov (United States)

    Tilstra, Jeremy S.; Gaddy, Daniel F.; Zhao, Jing; Davé, Shaival H.; Niedernhofer, Laura J.; Plevy, Scott E.; Robbins, Paul D.

    2014-01-01

    Monocyte-derived antigen presenting cells (APC) are central mediators of the innate and adaptive immune response in inflammatory diseases. As such, APC are appropriate targets for therapeutic intervention to ameliorate certain diseases. APC differentiation, activation and functions are regulated by the NF-κB family of transcription factors. Herein, we examined the effect of NF-κB inhibition, via suppression of the IκB Kinase (IKK) complex, on APC function. Murine bone marrow-derived macrophages and dendritic cells (DC), as well as macrophage and DC lines, underwent rapid programmed cell death (PCD) after treatment with several IKK/NF-κB inhibitors through a TNFα-dependent mechanism. PCD was induced proximally by reactive oxygen species (ROS) formation, which causes a loss of mitochondrial membrane potential and activation of a caspase signaling cascade. NF-κB-inhibition-induced PCD of APC may be a key mechanism through which therapeutic targeting of NF-κB reduces inflammatory pathologies.

  10. Autophagy Constitutes a Protective Mechanism against Ethanol Toxicity in Mouse Astrocytes and Neurons.

    Science.gov (United States)

    Pla, Antoni; Pascual, María; Guerri, Consuelo

    2016-01-01

    Ethanol induces brain damage and neurodegeneration by triggering inflammatory processes in glial cells through activation of Toll-like receptor 4 (TLR4) signaling. Recent evidence indicates the role of protein degradation pathways in neurodegeneration and alcoholic liver disease, but how these processes affect the brain remains elusive. We have demonstrated that chronic ethanol consumption impairs proteolytic pathways in mouse brain, and the immune response mediated by TLR4 receptors participates in these dysfunctions. We evaluate the in vitro effects of an acute ethanol dose on the autophagy-lysosome pathway (ALP) on WT and TLR4-/- mouse astrocytes and neurons in primary culture, and how these changes affect cell survival. Our results show that ethanol induces overexpression of several autophagy markers (ATG12, LC3-II, CTSB), and increases the number of lysosomes in WT astrocytes, effects accompanied by a basification of lysosomal pH and by lowered phosphorylation levels of autophagy inhibitor mTOR, along with activation of complexes beclin-1 and ULK1. Notably, we found only minor changes between control and ethanol-treated TLR4-/- mouse astroglial cells. Ethanol also triggers the expression of the inflammatory mediators iNOS and COX-2, but induces astroglial death only slightly. Blocking autophagy by using specific inhibitors increases both inflammation and cell death. Conversely, in neurons, ethanol down-regulates the autophagy pathway and triggers cell death, which is partially recovered by using autophagy enhancers. These results support the protective role of the ALP against ethanol-induced astroglial cell damage in a TLR4-dependent manner, and provide new insight into the mechanisms that underlie ethanol-induced brain damage and are neuronal sensitive to the ethanol effects. PMID:27070930

  11. Stress management by autophagy: Implications for chemoresistance.

    Science.gov (United States)

    Huang, Zhao; Zhou, Li; Chen, Zhibin; Nice, Edouard C; Huang, Canhua

    2016-07-01

    Development of chemoresistance, which limits the efficiency of anticancer agents, has long been a major problem in cancer therapy and urgently needs to be solved to improve clinical outcomes. Factors contributing to chemoresistance are various, but a key factor is the cell's capability for stress management. Autophagy, a favored survival strategy that organisms employ to get over many kinds of stress, is emerging as a crucial player in drug resistance. It has been shown that autophagy facilitates the resistance of tumor cells to anticancer agents, and abrogation of autophagy could be therapeutically beneficial in some cases, suggesting autophagy could be a promising target for cancer treatments. Thus, defining the roles of autophagy in chemoresistance, and the mechanisms involved, will be critical to enhance the efficiency of chemotherapy and develop novel anticancer strategy interventions. PMID:26757106

  12. Autophagy in the pathogenesis of ankylosing spondylitis.

    Science.gov (United States)

    Ciccia, Francesco; Haroon, Nigil

    2016-06-01

    The pathogenesis of ankylosing spondylitis (AS) is not well understood, and treatment options have met with limited success. Autophagy is a highly conserved mechanism of controlled digestion of damaged organelles within a cell. It helps in the maintenance of cellular homeostasis. The process of autophagy requires the formation of an isolation membrane. They form double-membraned vesicles called "autophagosomes" that engulf a portion of the cytoplasm. Beyond the role in maintenance of cellular homeostasis, autophagy has been demonstrated as one of the most remarkable tools employed by the host cellular defense against bacteria invasion. Autophagy also affects the immune system and thus is implicated in several rheumatic disease processes. In this article, we explore the potential role of autophagy in the pathogenesis of AS. PMID:27075464

  13. Insulin receptor substrate-1 prevents autophagy-dependent cell death caused by oxidative stress in mouse NIH/3T3 cells

    Directory of Open Access Journals (Sweden)

    Chan Shih-Hung

    2012-07-01

    Full Text Available Abstract Background Insulin receptor substrate (IRS-1 is associated with tumorigenesis; its levels are elevated in several human cancers. IRS-1 protein binds to several oncogene proteins. Oxidative stress and reactive oxygen species (ROS are involved in the initiation and progression of cancers. Cancer cells produce greater levels of ROS than normal cells do because of increased metabolic stresses. However, excessive production of ROS kills cancer cells. Autophagy usually serves as a survival mechanism in response to stress conditions, but excessive induction of autophagy results in cell death. In addition to inducing necrosis and apoptosis, ROS induces autophagic cell death. ROS inactivates IRS-1 mediated signaling and reduces intracellular IRS-1 concentrations. Thus, there is a complex relationship between IRS-1, ROS, autophagy, and cancer. It is not fully understood how cancer cells grow rapidly and survive in the presence of high ROS levels. Methods and results In this study, we established mouse NIH/3T3 cells that overexpressed IRS-1, so mimicking cancers with increased IRS-1 expression levels; we found that the IRS-1 overexpressing cells grow more rapidly than control cells do. Treatment of cells with glucose oxidase (GO provided a continuous source of ROS; low dosages of GO promoted cell growth, while high doses induced cell death. Evidence for GO induced autophagy includes increased levels of isoform B-II microtubule-associated protein 1 light chain 3 (LC3, aggregation of green fluorescence protein-tagged LC3, and increased numbers of autophagic vacuoles in cells. Overexpression of IRS-1 resulted in inhibition of basal autophagy, and reduced oxidative stress-induced autophagy and cell death. ROS decreased the mammalian target of rapamycin (mTOR/p70 ribosomal protein S6 kinase signaling, while overexpression of IRS-1 attenuated this inhibition. Knockdown of autophagy-related gene 5 inhibited basal autophagy and diminished oxidative stress

  14. Heme oxygenase‑1 protects H2O2‑insulted glomerular mesangial cells from excessive autophagy.

    Science.gov (United States)

    Xu, Jia; Li, Jinshun; Wang, Jinhua; Chi, Yanchun; Zhang, Kun; Cui, Rui

    2016-06-01

    Increasing evidence has demonstrated that the activation of heme oxygenase (HO)‑1 reduces autophagy stimulated by oxidative stress injury, in which the supraphysiological production of reactive oxygen species (ROS) is detected. However, the potential mechanism underlying this effect remains unclear. The present study aimed to investigate the function of HO‑1 activation in the regulation of autophagy in glomerular mesangial cells subjected to H2O2‑induced oxidative stress injury. The results demonstrated that the HO‑1 agonist, hemin, reduces the LC3 protein level, which was enhanced by H2O2 treatment. Furthermore, hemin‑activated HO‑1 may function as a regulator of oxidative stress‑induced autophagy in a dose‑dependent manner. Pharmacological activation of c‑Jun N‑terminal kinase (JNK) inhibited the effect of hemin, indicating that the JNK signaling pathway is associated with the mechanism of HO‑1 in impeding excessive autophagy. In addition to successfully alleviating H2O2‑induced oxidative stress and cellular apoptosis, hemin‑activated HO‑1 may provide cytoprotection against rapamycin, a specific autophagy agonist. The present result suggested the inhibitory action of HO‑1 in the avoidance of a potentially enhanced linkage between autophagy and apoptosis, particularly in the setting of excessive ROS. Therefore, enhancing the intracellular activity of HO‑1 may assist the crosstalk between oxidative stress, autophagy and apoptosis, and represent a novel therapeutic strategy for renal ischemic disease. PMID:27122182

  15. Autophagy and bacterial clearance: a not so clear picture

    OpenAIRE

    Mostowy, Serge

    2012-01-01

    Autophagy, an intracellular degradation process highly conserved from yeast to humans, is viewed as an important defence mechanism to clear intracellular bacteria. However, recent work has shown that autophagy may have different roles during different bacterial infections that restrict bacterial replication (antibacterial autophagy), act in cell autonomous signalling (non-bacterial autophagy) or support bacterial replication (pro-bacterial autophagy). This review will focus on newfound intera...

  16. Studies in neuroendocrine pharmacology

    Science.gov (United States)

    Maickel, R. P.

    1976-01-01

    The expertise and facilities available within the Medical Sciences Program section on Pharmacology were used along with informational input from various NASA sources to study areas relevant to the manned space effort. Topics discussed include effects of drugs on deprivation-induced fluid consumption, brain biogenic amines, biochemical responses to stressful stimuli, biochemical and behavioral pharmacology of amphetamines, biochemical and pharmacological studies of analogues to biologically active indole compounds, chemical pharmacology: drug metabolism and disposition, toxicology, and chemical methodology. Appendices include a bibliography, and papers submitted for publication or already published.

  17. Autophagy is involved in anti-viral activity of pentagalloylglucose (PGG) against Herpes simplex virus type 1 infection in vitro

    International Nuclear Information System (INIS)

    Research highlights: → We showed PGG has anti-viral activity against Herpes simplex virus type 1 (HSV-1) and can induce autophgy. → Autophagy may be a novel and important mechanism mediating PGG anti-viral activities. → Inhibition of mTOR pathway is an important mechanism of induction of autophagy by PGG. -- Abstract: Pentagalloylglucose (PGG) is a natural polyphenolic compound with broad-spectrum anti-viral activity, however, the mechanisms underlying anti-viral activity remain undefined. In this study, we investigated the effects of PGG on anti-viral activity against Herpes simplex virus type 1 (HSV-1) associated with autophagy. We found that the PGG anti-HSV-1 activity was impaired significantly in MEF-atg7-/- cells (autophagy-defective cells) derived from an atg7-/- knockout mouse. Transmission electron microscopy revealed that PGG-induced autophagosomes engulfed HSV-1 virions. The mTOR signaling pathway, an essential pathway for the regulation of autophagy, was found to be suppressed following PGG treatment. Data presented in this report demonstrated for the first time that autophagy induced following PGG treatment contributed to its anti-HSV activity in vitro.

  18. Autophagy in human embryonic stem cells.

    Directory of Open Access Journals (Sweden)

    Thien Tra

    Full Text Available Autophagy (macroautophagy is a degradative process that involves the sequestration of cytosolic material including organelles into double membrane vesicles termed autophagosomes for delivery to the lysosome. Autophagy is essential for preimplantation development of mouse embryos and cavitation of embryoid bodies. The precise roles of autophagy during early human embryonic development, remain however largely uncharacterized. Since human embryonic stem cells constitute a unique model system to study early human embryogenesis we investigated the occurrence of autophagy in human embryonic stem cells. We have, using lentiviral transduction, established multiple human embryonic stem cell lines that stably express GFP-LC3, a fluorescent marker for the autophagosome. Each cell line displays both a normal karyotype and pluripotency as indicated by the presence of cell types representative of the three germlayers in derived teratomas. GFP expression and labelling of autophagosomes is retained after differentiation. Baseline levels of autophagy detected in cultured undifferentiated hESC were increased or decreased in the presence of rapamycin and wortmannin, respectively. Interestingly, autophagy was upregulated in hESCs induced to undergo differentiation by treatment with type I TGF-beta receptor inhibitor SB431542 or removal of MEF secreted maintenance factors. In conclusion we have established hESCs capable of reporting macroautophagy and identify a novel link between autophagy and early differentiation events in hESC.

  19. Suppression of mTOR pathway and induction of autophagy-dependent cell death by cabergoline.

    Science.gov (United States)

    Lin, Shao Jian; Leng, Zhi Gen; Guo, Yu Hang; Cai, Lin; Cai, Yu; Li, Ning; Shang, Han Bing; Le, Wei-Dong; Zhao, Wei Guo; Wu, Zhe Bao

    2015-11-17

    Cabergoline (CAB), the first-line drug for treatment of prolactinomas, is effective in suppressing prolactin hypersecretion, reducing tumor size, and restoring gonadal function. However, mechanisms for CAB-mediated tumor shrinkage are largely unknown. Here we report a novel cytotoxic mechanism for CAB. CAB induced formation of autophagosome in rat pituitary tumor MMQ and GH3 cells at the early stage through inhibiting mTOR pathway, resulting in higher conversion rates of LC3-I to LC3-II, GFP-LC3 aggregation, and increased autophagosome formation. Interestingly, CAB treatment augmented lysosome acidification and resulted in impaired proteolytic degradation within autolysosomes. This blocked the autophagic flux, leading to the accumulation of p62 aggregation and undigested autolysosomes. Knockdown of ATG7, ATG5, or Becn1, could significantly rescue the CAB-mediated cell death of MMQ cells (p < 0.05). CAB-induced autophagy and blockade of autophagy flux participated in antitumoral action in vivo. In conclusion, our study provides evidence that CAB concomitantly induces autophagy and inhibits the autophagic flux, leading to autophagy-dependent cell death. These findings elucidate novel mechanisms for CAB action. PMID:26513171

  20. Nanoparticle-facilitated autophagy inhibition promotes the efficacy of chemotherapeutics against breast cancer stem cells.

    Science.gov (United States)

    Sun, Rong; Shen, Song; Zhang, Yun-Jiao; Xu, Cong-Fei; Cao, Zhi-Ting; Wen, Long-Ping; Wang, Jun

    2016-10-01

    Cancer stem cells (CSCs) have garnered increasing attention over the past decade, as they are believed to play a crucial role in tumor initiation, progression and metastasis, relapse and drug resistance. Therapeutic strategies which simultaneously exterminate both bulk tumor cells and the rare CSC subpopulation may produce striking response and result in long-term tumor remission. Accumulating evidence provides insight into the function of autophagy in maintenance, plasticity and survival of CSCs. The role of autophagy in the susceptibility of breast CSCs to chemotherapeutics was investigated in the present work, reduced 'stemness' and increased susceptibility to chemotherapy drugs (doxorubicin, DOX and docetaxel, DTXL) were observed after chloroquine (CQ)-mediated autophagy inhibition in sorted ALDH(hi) cells of breast cancer cell line MDA-MB-231. We further proved that nanoparticle-mediated autophagy inhibition promoted the efficacy of chemotherapeutics against ALDH(hi) MDA-MB-231 cells in vitro. Administration of drug delivery systems significantly prolonged the circulation half-life and augmented enrichment of two different drugs in tumor tissues and ALDH(hi) cells. More importantly, compared with single treatment, the combined delivery systems NPCQ/NPDOX and NPCQ/DOX (NPCQ/NPDTXL and NPCQ/DTXL) showed most effective and persistent tumor growth inhibitory effect by eliminating bulk tumor cells as well as CSCs (p breast cancer. PMID:27376558

  1. Transforming growth factor-β1 reduces apoptosis via autophagy activation in hepatic stellate cells

    Science.gov (United States)

    FU, MEI-YA; HE, YA-JUN; LV, XIA; LIU, ZHI-HE; SHEN, YAN; YE, GUO-RONG; DENG, YAN-MEI; SHU, JIAN-CHANG

    2014-01-01

    Autophagy is a metabolic process that is important in fibrogenesis, in which cellular components are degraded by lysosomal machinery. Transforming growth factor β1 (TGF-β1) is a potent fibrogenic cytokine involved in liver fibrosis; however, it remains elusive whether autophagy is regulated by TGF-β1 in this process. In the present study, the function of TGF-β1-mediated autophagy in the proliferation and apoptosis of hepatic stellate cells (HSCs) was investigated. A rat HSC cell line (HSC-T6) was incubated with or without TGF-β1 followed by bafilomycin A1, and microtubule-associated proteins 1A/1B light chain 3 (LC3) small interfering (si)RNA was used to inhibit autophagy in order to assess the association between TGF-β1 and autophagy. HSC-T6 cell transient transfection was accomplished with a pLVX-AcGFP-N1-rLC3B-encoding plasmid. An MTS assay and flow cytometry were utilized to detect proliferation and apoptosis of HSC-T6 cells. Quantitative polymerase chain reaction, immunofluorescence and western blot analysis were used to detect the presence of activation markers. Proliferation was increased and apoptosis was reduced in HSC-T6 cells treated with TGF-β1 compared with cells subjected to serum deprivation. However, when HSC-T6 cells were treated with bafilomycin A1 and LC3 siRNA, increased apoptosis and reduced proliferation were observed. In addition, protein and mRNA expression levels of the autophagy marker LC3 were significantly increased. GFP-LC3 punctate markings were more prolific following TGF-β1 treatment of HSC-T6 cells, indicating that TGF-β1 may rescue HSC-T6 cells from serum deprivation and reduce apoptosis via autophagy induction. The present study elucidated the possible functions of TGF-β1-mediated autophagy in the pathological process of liver fibrosis. PMID:25059289

  2. Pharmacological and dietary antioxidant therapies for chronic obstructive pulmonary disease.

    Science.gov (United States)

    Biswas, S; Hwang, J W; Kirkham, P A; Rahman, I

    2013-01-01

    /tirilazad, myeloperoxidase inhibitors, as well as specialized pro-resolving mediators/inflammatory resolving lipid mediators, omega-3 fatty acids, vitamin D, and hydrogen sulfide. According to various studies it appears that the administration of multiple antioxidants could be a more effective mode used in the treatment of COPD. In this review, various pharmacological and dietary approaches to enhance lung antioxidant levels and beneficial effects of antioxidant therapeutics in treating or intervening the progression of COPD have been discussed. PMID:22963552

  3. Autophagy in Atherosclerosis: A Phenomenon Found in Human Carotid Atherosclerotic Plaques

    Institute of Scientific and Technical Information of China (English)

    Huihui Liu; Yongjun Cao; Tong Tong; Jijun Shi; Yanlin Zhang; Yaping Yang; Chunfeng Liu

    2015-01-01

    Background:Autophagy has been found to be involved in animal and cell models ofatherosclerosis,but to date,it lacks general observation in human atherosclerotic plaques.Here,we investigated autophagy in smooth muscle cells (SMCs),endothelial cells (ECs),and macrophages in human atherosclerotic plaques via transmission electron microscopy (TEM),western blotting,and immunohistochemistry analysis.Methods:The histopathologic morphology of these plaques was observed via hematoxylin and eosin staining.The ultrastructural morphology of the SMCs,ECs,and macrophages in these plaques was observed via TEM.The localization ofmicrotubule-associated protein 1 light chain 3 (MAP 1-LC3),a relatively special maker ofautophagy,in plaques was observed by double fluorescent immunochemistty and western blotting.Results:All of these human atherosclerotic plaques were considered advanced and unstable in histologically observation.By double fluorescent immunochemistry,the expression of LC3-Ⅱ increased in the SMCs of the fibrous cap,the macrophages,and the microvascular ECs of the plaque shoulders.The protein level of LC3-Ⅱ by western blotting significantly increased in plaques compared with normal controls.In addition,TEM observation of plaques revealed certain features of autophagy in SMCs,ECs,and macrophages including the formation of myelin figures,vacuolization,and the accumulation of inclusions in the cytosol.These results indicate that autophagy is activated in SMCs,ECs,and macrophages in human advanced atherosclerotic plaques.Conclusions:Our study is to demonstrate the existence of autophagy in human atherosclerotic plaques by different methods,which may contribute to the development of pharmacological approaches to stabilize vulnerable and rupture-prone lesions.

  4. Pharmacology Information System Ready

    Science.gov (United States)

    Chemical and Engineering News, 1973

    1973-01-01

    Discusses the development and future of Prophet,'' a specialized information handling system for pharmacology research. It is designed to facilitate the acquisition and dissemination of knowledge about mechanisms of drug action, and it is hoped that it will aid in converting pharmacology research from an empirical to a predictive science. (JR)

  5. Curriculum Guidelines for Pharmacology.

    Science.gov (United States)

    Shaw, David H.; And Others

    1990-01-01

    Pharmacology embraces the physical and chemical properties of drugs; the preparation of pharmaceutical agents; the absorption, fate, and excretion of drugs; and the effects of drugs on living systems. These guidelines represent a consensus on what would constitute a minimally acceptable pharmacology course for predoctoral dental students. (MLW)

  6. Dihydroptychantol A, a macrocyclic bisbibenzyl derivative, induces autophagy and following apoptosis associated with p53 pathway in human osteosarcoma U2OS cells

    International Nuclear Information System (INIS)

    Dihydroptychantol A (DHA), a novel macrocyclic bisbibenzyl compound extracted from liverwort Asterella angusta, has antifungal and multi-drug resistance reversal properties. Here, the chemically synthesized DHA was employed to test its anti-cancer activities in human osteosarcoma U2OS cells. Our results demonstrated that DHA induced autophagy followed by apoptotic cell death accompanied with G2/M-phase cell cycle arrest in U2OS cells. DHA-induced autophagy was morphologically characterized by the formation of double membrane-bound autophagic vacuoles recognizable at the ultrastructural level. DHA also increased the levels of LC3-II, a marker of autophagy. Surprisingly, DHA-mediated apoptotic cell death was potentiated by the autophagy inhibitor 3-methyladenine, suggesting that autophagy may play a protective role that impedes the eventual cell death. Furthermore, p53 was shown to be involved in DHA-meditated autophagy and apoptosis. In this connection, DHA increased nuclear expression of p53, induced p53 phosphorylation, and upregulated p53 target gene p21Waf1/Cip1. In contrast, cytoplasmic p53 was reduced by DHA, which contributed to the stimulation of autophagy. In relation to the cell cycle, DHA decreased the expression of cyclin B1, a cyclin required for progression through the G2/M phase. Taken together, DHA induces G2/M-phase cell cycle arrest and apoptosis in U2OS cells. DHA-induced apoptosis was preceded by the induction of protective autophagy. DHA-mediated autophagy and apoptosis are associated with the cytoplasmic and nuclear functions of p53.

  7. Evolving insights on metabolism, autophagy and epigenetics in liver myofibroblasts

    Directory of Open Access Journals (Sweden)

    Zeribe Chike Nwosu

    2016-06-01

    Full Text Available Liver myofibroblasts (MFB are crucial mediators of extracellular matrix (ECM deposition in liver fibrosis. They arise mainly from hepatic stellate cells (HSCs upon a process termed activation. To a lesser extent, and depending on the cause of liver damage, portal fibroblasts, mesothelial cells and fibrocytes may also contribute to the MFB population. Targeting MFB to reduce liver fibrosis is currently an area of intense research. Unfortunately, a clog in the wheel of antifibrotic therapies is the fact that although MFB are known to mediate scar formation, and participate in liver inflammatory response, many of their molecular portraits are currently unknown. In this review, we discuss recent understanding of MFB in health and diseases, focusing specifically on three evolving research fields: metabolism, autophagy and epigenetics. We have emphasized on therapeutic prospects where applicable and mentioned techniques for use in MFB studies. Subsequently, we highlighted uncharted territories in MFB research to help direct future efforts aimed at bridging gaps in current knowledge.

  8. Oxidative stress-induced autophagy: Role in pulmonary toxicity

    International Nuclear Information System (INIS)

    Autophagy is an evolutionarily conserved catabolic process important in regulating the turnover of essential proteins and in elimination of damaged organelles and protein aggregates. Autophagy is observed in the lung in response to oxidative stress generated as a consequence of exposure to environmental toxicants. Whether autophagy plays role in promoting cell survival or cytotoxicity is unclear. In this article recent findings on oxidative stress-induced autophagy in the lung are reviewed; potential mechanisms initiating autophagy are also discussed. A better understanding of autophagy and its role in pulmonary toxicity may lead to the development of new strategies to treat lung injury associated with oxidative stress. - Highlights: • Exposure to pulmonary toxicants is associated with oxidative stress. • Oxidative stress is known to induce autophagy. • Autophagy is upregulated in the lung following exposure to pulmonary toxicants. • Autophagy may be protective or pathogenic

  9. Oxidative stress-induced autophagy: Role in pulmonary toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Malaviya, Rama [Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ 08854 (United States); Laskin, Jeffrey D. [Department of Environmental and Occupational Medicine, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ 08854 (United States); Laskin, Debra L., E-mail: laskin@eohsi.rutgers.edu [Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ 08854 (United States)

    2014-03-01

    Autophagy is an evolutionarily conserved catabolic process important in regulating the turnover of essential proteins and in elimination of damaged organelles and protein aggregates. Autophagy is observed in the lung in response to oxidative stress generated as a consequence of exposure to environmental toxicants. Whether autophagy plays role in promoting cell survival or cytotoxicity is unclear. In this article recent findings on oxidative stress-induced autophagy in the lung are reviewed; potential mechanisms initiating autophagy are also discussed. A better understanding of autophagy and its role in pulmonary toxicity may lead to the development of new strategies to treat lung injury associated with oxidative stress. - Highlights: • Exposure to pulmonary toxicants is associated with oxidative stress. • Oxidative stress is known to induce autophagy. • Autophagy is upregulated in the lung following exposure to pulmonary toxicants. • Autophagy may be protective or pathogenic.

  10. Autophagy induced by HIF1α overexpression supports trophoblast invasion by supplying cellular energy.

    Directory of Open Access Journals (Sweden)

    Mikiko Yamanaka-Tatematsu

    Full Text Available Extravillous trophoblasts (EVTs characterize the invasion of the maternal decidua under low oxygen and poor nutrition at the early feto-maternal interface to establish a successful pregnancy. We previously reported that autophagy in EVTs was activated under 2% O2 in vitro, and autophagy activation was also observed in EVTs at the early feto-maternal interface in vivo. Here, we show that autophagy is an energy source for the invasion of EVTs. Cobalt chloride (CoCl2, which induces hypoxia inducible factor 1α (HIF1α overexpression, activated autophagy in HTR8/SVneo cells, an EVT cell line. The number of invading HTR8-ATG4B(C74A cells, an autophagy-deficient EVT cell line, was markedly reduced by 81 percent with the CoCl2 treatment through the suppression of MMP9 level, although CoCl2 did not affect the cellular invasion of HTR8-mStrawberry cells, a control cell line. HTR8-ATG4B(C74A cells treated with CoCl2 showed a decrease in cellular adenosine triphosphate (ATP levels and a compensatory increase in the expression of purinergic receptor P2X ligand-gated ion channel 7 (P2RX7, which is stimulated with ATP, whereas HTR8-mStrawberry cells maintained cellular ATP levels and did not affect P2RX7 expression. Furthermore, the decreased invasiveness of HTR8-ATG4B(C74A cells treated with CoCl2 was neutralized by ATP supplementation to the level of HTR8-ATG4B(C74A cells treated without CoCl2. These results suggest that autophagy plays a role in maintaining homeostasis by countervailing HIF1α-mediated cellular energy consumption in EVTs.

  11. Role of autophagy in the bimodal stage after spinal cord ischemia reperfusion injury in rats.

    Science.gov (United States)

    Fang, Bo; Li, Xiao-Qian; Bao, Na-Ren; Tan, Wen-Fei; Chen, Feng-Shou; Pi, Xiao-Li; Zhang, Ying; Ma, Hong

    2016-07-22

    Autophagy plays an important role in spinal cord ischemia reperfusion (I/R) injury, but its neuroprotective or neurodegenerative role remains controversial. The extent and persistence of autophagy activation may be the critical factor to explain the opposing effects. In this study, the different roles and action mechanisms of autophagy in the early and later stages after I/R injury were investigated in rats. Thespinal cord I/R injury was induced by 14-min occlusion of the aortic arch, after which rats were treated with autophagic inhibitor (3-methyladenine, 3-MA) or agonist (rapamycin) immediately or 48h following the injury. Autophagy markers, microtubule-associated protein light chain 3-II (LC3-II) and Beclin 1 increased and peaked at the early stage (8h) and the later stage (72h) after spinal cord I/R injury. Beclin 1 was mostly expressed in neurons, but was also expressed to an extent in astrocytes, microglia and vascular endothelial cells. 8h after injury, rats treated with 3-MA showed a decrease in the hind-limb Basso-Beattie-Bresnahan (BBB) motor function scores, surviving motor neurons, and B-cell lymphoma-2 (Bcl-2) expression, and increase in the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL)-positive cells, Bcl-2-associated X protein (Bax), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) expression, and activation of microglia, while those treated with rapamycin showed opposing effects. However, 72h after injury, rats treated with 3-MA improved the BBB scores, and the surviving motor neurons, and reduced the autophagic cell death, while those treated with rapamycin had adverse effects. These findings provide the first evidence that early activated autophagy alleviates spinal cord I/R injury via inhibiting apoptosis and inflammation; however later excessively elevated autophagy aggravates I/R injury through inducing autophagic cell death. PMID:27109922

  12. Mechanisms of silver nanoparticle-induced toxicity and important role of autophagy.

    Science.gov (United States)

    Mao, Bin-Hsu; Tsai, Jui-Chen; Chen, Chun-Wan; Yan, Shian-Jang; Wang, Ying-Jan

    2016-10-01

    Safety concerns have been raised over the extensive applications of silver nanoparticles (AgNPs) because nano dimensions make them highly bioactive, being potentially harmful to the exposed humans. Surface physico-chemistry (shape, surface charge, chemical composition, etc.) that mainly dictates nano-bio interactions is relevant for influencing their biocompatibility and toxicity. Although the hazardousness of AgNPs has been demonstrated in vitro and in vivo, mechanistic understanding of the toxicity particularly at the molecular and organismal levels, in addition to oxidative stress and silver ion dissolution, has remained unclear. A growing body of research has elucidated that autophagy, being activated in response to exposure to various nanomaterials, may serve as a cellular defense mechanism against nanotoxicity. Recently, autophagy activation was shown to correlate with AgNPs exposure; however, the subsequent autophagosome-lysosome fusion was defective. As autophagy plays a crucial role in selective removal of stress-mediated protein aggregates and injured organelles, AgNPs-induced autophagic flux defect may consequently lead to aggravated cytotoxic responses. Furthermore, we suggest that p62 accumulation resulting from defective autophagy may also potentially account for AgNPs cytotoxicity. Intriguingly, AgNPs have been shown to interfere with ubiquitin modifications, either via upregulating levels of enzymes participating in ubiquitination, or through impairing the biological reactivity of ubiquitin (due to formation of AgNPs-ubiquitin corona). Ubiquitination both confers selectivity to autophagy as well as modulates stabilization, activation, and trafficking of proteins involved in autophagic clearance pathways. In this regard, we offer a new perspective that interference of AgNPs with ubiquitination may account for AgNPs-induced defective autophagy and cytotoxic effects. PMID:27240148

  13. Receptor-Bound Targets of Selective Autophagy Use a Scaffold Protein to Activate the Atg1 Kinase.

    Science.gov (United States)

    Kamber, Roarke A; Shoemaker, Christopher J; Denic, Vladimir

    2015-08-01

    Selective autophagy eliminates protein aggregates, damaged organelles, and other targets that otherwise accumulate and cause disease. Autophagy receptors mediate selectivity by connecting targets to the autophagosome membrane. It has remained unknown whether receptors perform additional functions. Here, we show that in yeast certain receptor-bound targets activate Atg1, the kinase that controls autophagosome formation. Specifically, we found that in nutrient-rich conditions, Atg1 is active only in a multisubunit complex comprising constitutive protein aggregates, their autophagy receptor, and a scaffold protein, Atg11. Development of a cell-free assay for Atg1-mediated phosphorylation enabled us to activate Atg1 with purified receptor-bound aggregates and Atg11. Another target, damaged peroxisomes, also activated Atg1 using Atg11 with a distinct receptor. Our work reveals that receptor-target complexes activate Atg1 to drive formation of selective autophagosomes. This regulatory logic is a key similarity between selective autophagy and bulk autophagy, which is initiated by a distinct Atg1 activation mechanism during starvation. PMID:26166702

  14. Targeted siRNA Screens Identify ER-to-Mitochondrial Calcium Exchange in Autophagy and Mitophagy Responses in RPE1 Cells

    Directory of Open Access Journals (Sweden)

    Thomas D. B. MacVicar

    2015-06-01

    Full Text Available Autophagy is an important stress response pathway responsible for the removal and recycling of damaged or redundant cytosolic constituents. Mitochondrial damage triggers selective mitochondrial autophagy (mitophagy, mediated by a variety of response factors including the Pink1/Parkin system. Using human retinal pigment epithelial cells stably expressing autophagy and mitophagy reporters, we have conducted parallel screens of regulators of endoplasmic reticulum (ER and mitochondrial morphology and function contributing to starvation-induced autophagy and damage-induced mitophagy. These screens identified the ER chaperone and Ca2+ flux modulator, sigma non-opioid intracellular receptor 1 (SIGMAR1, as a regulator of autophagosome expansion during starvation. Screens also identified phosphatidyl ethanolamine methyl transferase (PEMT and the IP3-receptors (IP3Rs as mediators of Parkin-induced mitophagy. Further experiments suggested that IP3R-mediated transfer of Ca2+ from the ER lumen to the mitochondrial matrix via the mitochondrial Ca2+ uniporter (MCU primes mitochondria for mitophagy. Importantly, recruitment of Parkin to damaged mitochondria did not require IP3R-mediated ER-to-mitochondrial Ca2+ transfer, but mitochondrial clustering downstream of Parkin recruitment was impaired, suggesting involvement of regulators of mitochondrial dynamics and/or transport. Our data suggest that Ca2+ flux between ER and mitochondria at presumed ER/mitochondrial contact sites is needed both for starvation-induced autophagy and for Parkin-mediated mitophagy, further highlighting the importance of inter-organellar communication for effective cellular homeostasis.

  15. Autophagy in lung disease pathogenesis and therapeutics

    OpenAIRE

    Ryter, Stefan W.; Augustine M K Choi

    2015-01-01

    Autophagy, a cellular pathway for the degradation of damaged organelles and proteins, has gained increasing importance in human pulmonary diseases, both as a modulator of pathogenesis and as a potential therapeutic target. In this pathway, cytosolic cargos are sequestered into autophagosomes, which are delivered to the lysosomes where they are enzymatically degraded and then recycled as metabolic precursors. Autophagy exerts an important effector function in the regulation of inflammation, an...

  16. Skeletal Muscle Autophagy: A New Metabolic Regulator

    OpenAIRE

    Neel, Brian A.; Lin, Yuxi; Pessin, Jeffrey E.

    2013-01-01

    Autophagy classically functions as a physiological process to degrade cytoplasmic components, protein aggregates, and/or organelles, as a mechanism for nutrient breakdown, and as a regulator of cellular architecture. Proper autophagic flux is vital for both functional skeletal muscle, which controls support and movement of the skeleton, and muscle metabolism. The role of autophagy as a metabolic regulator in muscle has been previously studied; however, the underlying molecular mechanisms that...

  17. The role of autophagy in Parkinson's disease☆

    OpenAIRE

    Zhang, Lei; Dong, Yaru; Xu, Xiaoheng; Xu, Zhong

    2012-01-01

    Although Parkinson's disease is the most common neurodegenerative movement disorder, the mechanisms of pathogenesis remain poorly understood. Recent findings have shown that deregulation of the autophagy-lysosome pathway is involved in the pathogenesis of Parkinson's disease. This review summarizes the most recent findings and discusses the unique role of the autophagy-lysosome pathway in Parkinson's disease to highlight the possibility of Parkinson's disease treatment strategies that incorpo...

  18. Mechanisms of mitochondria and autophagy crosstalk

    OpenAIRE

    Rambold, Angelika S.; Lippincott-Schwartz, Jennifer

    2011-01-01

    Autophagy is a cellular survival pathway that recycles intracellular components to compensate for nutrient depletion and ensures the appropriate degradation of organelles. Mitochondrial number and health are regulated by mitophagy, a process by which excessive or damaged mitochondria are subjected to autophagic degradation. Autophagy is thus a key determinant for mitochondrial health and proper cell function. Mitophagic malfunction has been recently proposed to contribute to progressive neuro...

  19. Identification of Signaling Pathways by Which CD40 Stimulates Autophagy and Antimicrobial Activity against Toxoplasma gondii in Macrophages.

    Science.gov (United States)

    Liu, Elizabeth; Lopez Corcino, Yalitza; Portillo, Jose-Andres C; Miao, Yanling; Subauste, Carlos S

    2016-09-01

    CD40 is an important stimulator of autophagy and autophagic killing of Toxoplasma gondii in host cells. In contrast to autophagy induced by nutrient deprivation or pattern recognition receptors, less is known about the effects of cell-mediated immunity on Beclin 1 and ULK1, key regulators of autophagy. Here we studied the molecular mechanisms by which CD40 stimulates autophagy in macrophages. CD40 ligation caused biphasic Jun N-terminal protein kinase (JNK) phosphorylation. The second phase of JNK phosphorylation was dependent on autocrine production of tumor necrosis factor alpha (TNF-α). TNF-α and JNK signaling were required for the CD40-induced increase in autophagy. JNK signaling downstream of CD40 caused Ser-87 phosphorylation of Bcl-2 and dissociation between Bcl-2 and Beclin 1, an event known to stimulate the autophagic function of Beclin 1. However, TNF-α alone was unable to stimulate autophagy. CD40 also stimulated autophagy via a pathway that included calcium/calmodulin-dependent kinase kinase β (CaMKKβ), AMP-activated protein kinase (AMPK), and ULK1. CD40 caused AMPK phosphorylation at its activating site, Thr-172. This effect was mediated by CaMKKβ and was not impaired by neutralization of TNF-α. CD40 triggered AMPK-dependent Ser-555 phosphorylation of ULK1. CaMKKβ, AMPK, and ULK1 were required for CD40-induced increase in autophagy. CD40-mediated autophagic killing of Toxoplasma gondii is known to require TNF-α. Knockdown of JNK, CaMKKβ, AMPK, or ULK1 prevented T. gondii killing in CD40-activated macrophages. The second phase of JNK phosphorylation-Bcl-2 phosphorylation-Bcl-2-Beclin 1 dissociation and AMPK phosphorylation-ULK1 phosphorylation occurred simultaneously at ∼4 h post-CD40 stimulation. Thus, CaMKKβ and TNF-α are upstream molecules by which CD40 acts on ULK1 and Beclin 1 to stimulate autophagy and killing of T. gondii. PMID:27354443

  20. RUFY4: Immunity piggybacking on autophagy?

    Science.gov (United States)

    Terawaki, Seigo; Camosseto, Voahirana; Pierre, Philippe; Gatti, Evelina

    2016-03-01

    Although autophagy is a highly conserved mechanism among species and cell types, few are the molecules involved with the autophagic process that display cell- or tissue- specific expression. We have unraveled the positive regulatory role on autophagy of RUFY4 (RUN and FYVE domain containing 4), which is expressed in subsets of immune cells, including dendritic cells (DCs). DCs orchestrate the eradication of pathogens by coordinating the action of the different cell types involved in microbe recognition and destruction during the immune response. To fulfill this function, DC display particular regulation of their endocytic and autophagy pathways in response to the immune environment. Autophagy flux is downmodulated in DCs upon microbe sensing, but is remarkably augmented, when cells are differentiated in the presence of the pleiotropic cytokine IL4 (interleukin 4). From gene expression studies aimed at comparing the impact of IL4 on DC differentiation, we identified RUFY4, as a novel regulator that augments autophagy flux and, when overexpressed, induces drastic membrane redistribution and strongly tethers lysosomes. RUFY4 is therefore one of the few known positive regulators of autophagy that is expressed in a cell-specific manner or under specific immunological conditions associated with IL4 expression such as allergic asthma. PMID:26760128

  1. Autophagy in the control of food intake.

    Science.gov (United States)

    Singh, Rajat

    2012-04-01

    The cellular nutrient sensing apparatus detects nutritional depletion and transmits this information to downstream effectors that generate energy from alternate sources. Autophagy is a crucial catabolic pathway that turns over redundant cytoplasmic components in lysosomes to provide energy to the starved cell. Recent studies have described a role for hypothalamic autophagy in the control of food intake and energy balance. Activated autophagy in hypothalamic neurons during starvation mobilized neuron-intrinsic lipids to generate free fatty acids that increased AgRP levels. AgRP neuron-specific inhibition of autophagy decreased fasting-induced increases in AgRP levels and food intake. Deletion of autophagy in AgRP neurons led to constitutive increases in levels of proopiomelanocortin and its active processed product, α-melanocyte stimulating hormone that contributed to reduced adiposity in these rodents. The current manuscript discusses these new findings and raises additional questions that may help understand how hypothalamic autophagy controls food intake and energy balance. These studies may have implications for designing new therapies against obesity and insulin resistance. PMID:23700515

  2. Dengue Virus Nonstructural Protein 1 Induces Vascular Leakage through Macrophage Migration Inhibitory Factor and Autophagy.

    Science.gov (United States)

    Chen, Hong-Ru; Chuang, Yung-Chun; Lin, Yee-Shin; Liu, Hsiao-Sheng; Liu, Ching-Chuan; Perng, Guey-Chuen; Yeh, Trai-Ming

    2016-07-01

    Dengue virus (DENV) is the most common mosquito-borne flavivirus; it can either cause mild dengue fever or the more severe dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). One of the characteristic features of DHF/DSS is vascular leakage; although DENV nonstructural protein 1 (NS1) has been proved to induce vascular leakage after binding to Toll-like receptor 4, the down-stream mechanism has not yet been fully understood. In the sera of DENV-infected patients, the concentrations of DENV NS1 and inflammatory cytokine macrophage migration inhibitory factor (MIF) are positively correlated with disease severity, but whether DENV NS1 induces vascular leakage through MIF secretion remains unknown. We demonstrated that recombinant NS1 induced vascular leakage and MIF secretion both in human endothelial cell line HMEC-1 and in mice. Furthermore, these phenomena were inhibited in the presence of anti-NS1 antibodies both in vitro and in vivo. DENV NS1 also induced LC3-I to LC3-II conversion and p62 degradation in endothelial cell line, which indicated the formation of autophagy. To clarify whether MIF or autophagy mediated DENV NS1-induced vascular leakage, various inhibitors were applied. The results showed that DENV NS1-induced vascular leakage and VE-cadherin disarray were blocked in the presence of MIF inhibitors, anti-MIF-antibodies or autophagy inhibitors. An Atg5 knockdown clone further confirmed that autophagy formation of endothelial cells was required in NS1-induced vascular leakage. Furthermore, DENV NS1-induced LC3 puncta were also decreased in the presence of MIF inhibitors, indicating that MIF mediated DENV NS1-induced autophagy. Taken together, the results suggest a potential mechanism of DENV-induced vascular leakage and provide possible therapeutic targets against DHF/DSS. PMID:27409803

  3. Dengue Virus Nonstructural Protein 1 Induces Vascular Leakage through Macrophage Migration Inhibitory Factor and Autophagy

    Science.gov (United States)

    Chen, Hong-Ru; Chuang, Yung-Chun; Lin, Yee-Shin; Liu, Hsiao-Sheng; Liu, Ching-Chuan; Perng, Guey-Chuen

    2016-01-01

    Dengue virus (DENV) is the most common mosquito-borne flavivirus; it can either cause mild dengue fever or the more severe dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). One of the characteristic features of DHF/DSS is vascular leakage; although DENV nonstructural protein 1 (NS1) has been proved to induce vascular leakage after binding to Toll-like receptor 4, the down-stream mechanism has not yet been fully understood. In the sera of DENV-infected patients, the concentrations of DENV NS1 and inflammatory cytokine macrophage migration inhibitory factor (MIF) are positively correlated with disease severity, but whether DENV NS1 induces vascular leakage through MIF secretion remains unknown. We demonstrated that recombinant NS1 induced vascular leakage and MIF secretion both in human endothelial cell line HMEC-1 and in mice. Furthermore, these phenomena were inhibited in the presence of anti-NS1 antibodies both in vitro and in vivo. DENV NS1 also induced LC3-I to LC3-II conversion and p62 degradation in endothelial cell line, which indicated the formation of autophagy. To clarify whether MIF or autophagy mediated DENV NS1-induced vascular leakage, various inhibitors were applied. The results showed that DENV NS1-induced vascular leakage and VE-cadherin disarray were blocked in the presence of MIF inhibitors, anti-MIF-antibodies or autophagy inhibitors. An Atg5 knockdown clone further confirmed that autophagy formation of endothelial cells was required in NS1-induced vascular leakage. Furthermore, DENV NS1-induced LC3 puncta were also decreased in the presence of MIF inhibitors, indicating that MIF mediated DENV NS1-induced autophagy. Taken together, the results suggest a potential mechanism of DENV-induced vascular leakage and provide possible therapeutic targets against DHF/DSS. PMID:27409803

  4. Spliced XBP1 promotes macrophage survival and autophagy by interacting with Beclin-1

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Ping-Ge [Southern Medical University, Guangzhou, Guangdong 510515 (China); Jiang, Zhi-Xin [Centre Laboratory, The 305th Hospital of the People' s Liberation Army, Beijing 100017 (China); Li, Jian-Hua [Department of Geriatric Cardiology, Chinese PLA General Hosptial, Beijing 100853 (China); Zhou, Zhe, E-mail: zhouzhe76@126.com [Laboratory of Biotechnology, Beijing Institute of Radiation Medicine, Beijing 100850 (China); Zhang, Qing-Hua, E-mail: 1056055170@qq.com [Department of Cardiology, The 305th Hospital of the People' s Liberation Army, Beijing 100017 (China)

    2015-08-07

    Macrophage autophagy plays an important role in the development of atherosclerosis, but the precise mechanism mediating this process is unclear. The potential role of the X-box binding protein 1 (XBP1), a crucial transduction factor that is involved in endoplasmic reticulum stress and the unfolded protein response, in bone marrow-derived macrophage autophagy is unknown. This study mainly explores the roles of XBP1 mRNA splicing in bone marrow-derived macrophage autophagy. The present study shows that the transient overexpression of spliced XBP1 via adenovirus-mediated gene transfer induces autophagy and promotes proliferation in bone marrow-derived macrophages via the down-regulation of Beclin-1, but that the sustained overexpression of spliced XBP1 leads to apoptosis. When XBP1 is down-regulated in bone marrow-derived macrophages using siRNA, rapamycin-induced autophagosome formation is ablated. Furthermore, we have detected the overexpression of XBP1 in areas of atherosclerotic plaques in the arteries of ApoE−/− mice. These results demonstrate that XBP1 mRNA splicing plays an important role in maintaining the function of bone marrow-derived macrophages and provide new insight into the study and treatment of atherosclerosis. - Highlights: • XBP1 was up-regulated in atherosclerotic plaques of ApoE−/− mice. • Transient spliced XBP1 overexpression induced macrophages autophagy via Beclin-1. • Sustained spliced XBP1 overexpression triggered macrophages apoptosis. • Spliced XBP1 plays a key role in maintaining the macrophages survival.

  5. Spliced XBP1 promotes macrophage survival and autophagy by interacting with Beclin-1

    International Nuclear Information System (INIS)

    Macrophage autophagy plays an important role in the development of atherosclerosis, but the precise mechanism mediating this process is unclear. The potential role of the X-box binding protein 1 (XBP1), a crucial transduction factor that is involved in endoplasmic reticulum stress and the unfolded protein response, in bone marrow-derived macrophage autophagy is unknown. This study mainly explores the roles of XBP1 mRNA splicing in bone marrow-derived macrophage autophagy. The present study shows that the transient overexpression of spliced XBP1 via adenovirus-mediated gene transfer induces autophagy and promotes proliferation in bone marrow-derived macrophages via the down-regulation of Beclin-1, but that the sustained overexpression of spliced XBP1 leads to apoptosis. When XBP1 is down-regulated in bone marrow-derived macrophages using siRNA, rapamycin-induced autophagosome formation is ablated. Furthermore, we have detected the overexpression of XBP1 in areas of atherosclerotic plaques in the arteries of ApoE−/− mice. These results demonstrate that XBP1 mRNA splicing plays an important role in maintaining the function of bone marrow-derived macrophages and provide new insight into the study and treatment of atherosclerosis. - Highlights: • XBP1 was up-regulated in atherosclerotic plaques of ApoE−/− mice. • Transient spliced XBP1 overexpression induced macrophages autophagy via Beclin-1. • Sustained spliced XBP1 overexpression triggered macrophages apoptosis. • Spliced XBP1 plays a key role in maintaining the macrophages survival

  6. DAMPs and autophagy: Cellular adaptation to injury and unscheduled cell death

    OpenAIRE

    Zhang, Qiuhong; Kang, Rui; Zeh, III, Herbert J.; Lotze, Michael T; Tang, Daolin

    2013-01-01

    Autophagy is a lysosome-mediated catabolic process involving the degradation of intracellular contents (e.g., proteins and organelles) as well as invading microbes (e.g., parasites, bacteria and viruses). Multiple forms of cellular stress can stimulate this pathway, including nutritional imbalances, oxygen deprivation, immunological response, genetic defects, chromosomal anomalies and cytotoxic stress. Damage-associated molecular pattern molecules (DAMPs) are released by stressed cells underg...

  7. Disturbed Flow Induces Autophagy, but Impairs Autophagic Flux to Perturb Mitochondrial Homeostasis

    Science.gov (United States)

    Li, Rongsong; Jen, Nelson; Wu, Lan; Lee, Juhyun; Fang, Karen; Quigley, Katherine; Lee, Katherine; Wang, Sky; Zhou, Bill; Vergnes, Laurent; Chen, Yun-Ru; Li, Zhaoping; Reue, Karen; Ann, David K.

    2015-01-01

    Abstract Aim: Temporal and spatial variations in shear stress are intimately linked with vascular metabolic effects. Autophagy is tightly regulated in intracellular bulk degradation/recycling system for maintaining cellular homeostasis. We postulated that disturbed flow modulates autophagy with an implication in mitochondrial superoxide (mtO2•−) production. Results: In the disturbed flow or oscillatory shear stress (OSS)-exposed aortic arch, we observed prominent staining of p62, a reverse marker of autophagic flux, whereas in the pulsatile shear stress (PSS)-exposed descending aorta, p62 was attenuated. OSS significantly increased (i) microtubule-associated protein light chain 3 (LC3) II to I ratios in human aortic endothelial cells, (ii) autophagosome formation as quantified by green fluorescent protein (GFP)-LC3 dots per cell, and (iii) p62 protein levels, whereas manganese superoxide dismutase (MnSOD) overexpression by recombinant adenovirus, N-acetyl cysteine treatment, or c-Jun N-terminal kinase (JNK) inhibition reduced OSS-mediated LC3-II/LC3-I ratios and mitochondrial DNA damage. Introducing bafilomycin to Earle's balanced salt solution or to OSS condition incrementally increased both LC3-II/LC3-I ratios and p62 levels, implicating impaired autophagic flux. In the OSS-exposed aortic arch, both anti-phospho-JNK and anti-8-hydroxy-2′-deoxyguanosine (8-OHdG) staining for DNA damage were prominent, whereas in the PSS-exposed descending aorta, the staining was nearly absent. Knockdown of ATG5 with siRNA increased OSS-mediated mtO2•−, whereas starvation or rapamycin-induced autophagy reduced OSS-mediated mtO2•−, mitochondrial respiration, and complex II activity. Innovation: Disturbed flow-mediated oxidative stress and JNK activation induce autophagy. Conclusion: OSS impairs autophagic flux to interfere with mitochondrial homeostasis. Antioxid. Redox Signal. 23, 1207–1219. PMID:26120766

  8. Statistics in Pharmacology

    OpenAIRE

    Spina, D.

    2007-01-01

    Statistics is an important tool in pharmacological research that is used to summarize (descriptive statistics) experimental data in terms of central tendency (mean or median) and variance (standard deviation, standard error of the mean, confidence interval or range) but more importantly it enables us to conduct hypothesis testing. This is of particular importance when attempting to determine whether the pharmacological effect of one drug is superior to another which clearly has implications f...

  9. Who needs pharmacologic therapy?

    Directory of Open Access Journals (Sweden)

    Christopher Porterfield; Rohit Malhotra

    2014-06-01

    Full Text Available Treatment of atrial fibrillation has evolved significantly in the last ten years, with ablation becoming a far more common form of treatment for this most common of arrhythmias. However, while ablation has become more common, certain populations derive continued benefit from the use of pharmacologic therapy for treatment. We review the use of pharmacologic therapy and novel considerations for treatment of atrial fibrillation.

  10. Mitochondrial biogenesis: pharmacological approaches.

    Science.gov (United States)

    Valero, Teresa

    2014-01-01

    Organelle biogenesis is concomitant to organelle inheritance during cell division. It is necessary that organelles double their size and divide to give rise to two identical daughter cells. Mitochondrial biogenesis occurs by growth and division of pre-existing organelles and is temporally coordinated with cell cycle events [1]. However, mitochondrial biogenesis is not only produced in association with cell division. It can be produced in response to an oxidative stimulus, to an increase in the energy requirements of the cells, to exercise training, to electrical stimulation, to hormones, during development, in certain mitochondrial diseases, etc. [2]. Mitochondrial biogenesis is therefore defined as the process via which cells increase their individual mitochondrial mass [3]. Recent discoveries have raised attention to mitochondrial biogenesis as a potential target to treat diseases which up to date do not have an efficient cure. Mitochondria, as the major ROS producer and the major antioxidant producer exert a crucial role within the cell mediating processes such as apoptosis, detoxification, Ca2+ buffering, etc. This pivotal role makes mitochondria a potential target to treat a great variety of diseases. Mitochondrial biogenesis can be pharmacologically manipulated. This issue tries to cover a number of approaches to treat several diseases through triggering mitochondrial biogenesis. It contains recent discoveries in this novel field, focusing on advanced mitochondrial therapies to chronic and degenerative diseases, mitochondrial diseases, lifespan extension, mitohormesis, intracellular signaling, new pharmacological targets and natural therapies. It contributes to the field by covering and gathering the scarcely reported pharmacological approaches in the novel and promising field of mitochondrial biogenesis. There are several diseases that have a mitochondrial origin such as chronic progressive external ophthalmoplegia (CPEO) and the Kearns- Sayre syndrome (KSS

  11. Mycobacterium tuberculosis EIS gene inhibits macrophage autophagy through up-regulation of IL-10 by increasing the acetylation of histone H3.

    Science.gov (United States)

    Duan, Liang; Yi, Min; Chen, Juan; Li, Shengjin; Chen, Weixian

    2016-05-13

    Autophagy plays a crucial role in the progress of Mycobacterium tuberculosis (MTB) infection. Recently, MTB enhanced intracellular survival (EIS) protein was reported to be secreted from MTB cells and linked to the inhibition of autophagy and the intracellular persistence of the pathogen. Here, we investigated the mechanism of EIS-mediated inhibition of autophagy in a human phorbol myristate acetate (PMA)-treated THP-1 cell line as well as in murine macrophages. We confirmed that the presence of EIS led to the inhibition of rapamycin (Rapa)-induced autophagy, while IL-10 gene expression was increased and Akt/mTOR/p70S6K pathway was activated during the process. IL-10 gene silencing led to a significant recovery of EIS-mediated autophagy suppression and decreased activity of the Akt/mTOR/p70S6K pathway. IL-10 promoter activity was unaffected by EIS. Remarkably, EIS increased the acetylation level of histone H3 (Ac-H3), which binds to the SP1 and STAT3 region of the human IL-10 gene promoter sequence. Thus, EIS protein possibly increased IL-10 expression through the regulation of Ac-H3 of its promoter. Our data demonstrated that one possible mechanism of the MTB evasion of autophagy is that the EIS protein up-regulates IL-10 via Ac-H3 and thus activates Akt/mTOR/p70S6K pathway. PMID:27079235

  12. Characterization of early autophagy signaling by quantitative phosphoproteomics

    DEFF Research Database (Denmark)

    Rigbolt, Kristoffer Tg; Zarei, Mostafa; Sprenger, Adrian;

    2014-01-01

    Under conditions of nutrient shortage autophagy is the primary cellular mechanism ensuring availability of substrates for continuous biosynthesis. Subjecting cells to starvation or rapamycin efficiently induces autophagy by inhibiting the MTOR signaling pathway triggering increased autophagic flu...

  13. Autophagy as a target for cancer therapy: new developments

    International Nuclear Information System (INIS)

    Autophagy is an evolutionarily conserved lysosomal degradation pathway that eliminates cytosolic proteins, macromolecules, organelles, and protein aggregates. Activation of autophagy may function as a tumor suppressor by degrading defective organelles and other cellular components. However, this pathway may also be exploited by cancer cells to generate nutrients and energy during periods of starvation, hypoxia, and stress induced by chemotherapy. Therefore, induction of autophagy has emerged as a drug resistance mechanism that promotes cancer cell survival via self-digestion. Numerous preclinical studies have demonstrated that inhibition of autophagy enhances the activity of a broad array of anticancer agents. Thus, targeting autophagy may be a global anticancer strategy that may improve the efficacy of many standard of care agents. These results have led to multiple clinical trials to evaluate autophagy inhibition in combination with conventional chemotherapy. In this review, we summarize the anticancer agents that have been reported to modulate autophagy and discuss new developments in autophagy inhibition as an anticancer strategy

  14. High glucose environment inhibits cranial neural crest survival by activating excessive autophagy in the chick embryo

    Science.gov (United States)

    Wang, Xiao-Yu; Li, Shuai; Wang, Guang; Ma, Zheng-Lai; Chuai, Manli; Cao, Liu; Yang, Xuesong

    2015-01-01

    High glucose levels induced by maternal diabetes could lead to defects in neural crest development during embryogenesis, but the cellular mechanism is still not understood. In this study, we observed a defect in chick cranial skeleton, especially parietal bone development in the presence of high glucose levels, which is derived from cranial neural crest cells (CNCC). In early chick embryo, we found that inducing high glucose levels could inhibit the development of CNCC, however, cell proliferation was not significantly involved. Nevertheless, apoptotic CNCC increased in the presence of high levels of glucose. In addition, the expression of apoptosis and autophagy relevant genes were elevated by high glucose treatment. Next, the application of beads soaked in either an autophagy stimulator (Tunicamycin) or inhibitor (Hydroxychloroquine) functionally proved that autophagy was involved in regulating the production of CNCC in the presence of high glucose levels. Our observations suggest that the ERK pathway, rather than the mTOR pathway, most likely participates in mediating the autophagy induced by high glucose. Taken together, our observations indicated that exposure to high levels of glucose could inhibit the survival of CNCC by affecting cell apoptosis, which might result from the dysregulation of the autophagic process. PMID:26671447

  15. MicroRNA-21 activation of ERK signaling via PTEN is involved in arsenite-induced autophagy in human hepatic L-02 cells.

    Science.gov (United States)

    Liu, Xinlu; Luo, Fei; Ling, Min; Lu, Lu; Shi, Le; Lu, Xiaolin; Xu, Hui; Chen, Chao; Yang, Qianlei; Xue, Junchao; Li, Jun; Zhang, Aihua; Liu, Qizhan

    2016-06-11

    Autophagy, an evolutionarily conserved cellular process, has diverse physiological and pathological roles in biological functions. Whether autophagy is induced by arsenite, a well-established human carcinogen, and the molecular mechanisms involved, remain to be established. Further, microRNAs (miRNAs) act as regulators in various cancers, but how miRNAs regulate autophagy remains largely unexplored. We have found that, in human hepatic epithelial (L-02) cells, arsenite increases levels of autophagy-related proteins in a concentration- and time-dependent manner and elevates the number of autophagic vacuoles (AVs). Arsenite also activates the ERK pathway in a dose- and time-dependent manner. In L-02 cells exposed to arsenite, microRNA-21 (miRNA-21) is over-expressed, and its target proteins, PTEN, PDCD4, and Spry1, are decreased. Moreover, inhibition of miR-21 increases levels of PTEN, and reduces levels of Beclin 1 and LC3 II/I, indicating that miR-21 is involved in arsenite-induced autophagy. In addition, ectopic expression of PTEN blocks the effect of miR-21 on the arsenite-induced autophagy and decreases p-ERK levels. Also, ERK promotes the autophagy induced by arsenite. In sum, upon exposure of cells to arsenite, over-expression of miR-21 activates ERK through PTEN, factors that participate in arsenite-induced autophagy. This link, mediated through miRNAs, establishes a mechanism for the development of autophagy that is associated with arsenic toxicity. Such information contributes to an understanding of the liver toxicity caused by arsenite. PMID:27107786

  16. Dual role of autophagy in HIV-1 replication and pathogenesis

    OpenAIRE

    Killian M

    2012-01-01

    Abstract Autophagy, the major mechanism for degrading long-lived intracellular proteins and organelles, is essential for eukaryotic cell homeostasis. Autophagy also defends the cell against invasion by microorganisms and has important roles in innate and adaptive immunity. Increasingly evident is that HIV-1 replication is dependent on select components of autophagy. Fittingly, HIV-1 proteins are able to modulate autophagy to maximize virus production. At the same time, HIV-1 proteins appear t...

  17. Bone Cell Autophagy Is Regulated by Environmental Factors

    OpenAIRE

    Zahm, Adam M.; Bohensky, Jolene; Adams, Christopher S.; Shapiro, Irving M.; Srinivas, Vickram

    2011-01-01

    The goal of this investigation was to ascertain whether bone cells undergo autophagy and to determine if this process is regulated by environmental factors. We showed that osteocytes in both murine and human cortical bone display a punctuate distribution of microtubule-associated protein light chain 3, indicative of autophagy. In addition, we noted a basal level of autophagy in preosteocyte-like murine long bone-derived osteocytic (MLO)-A5 cells. Autophagy was upregulated following nutrient d...

  18. Interactions between Shigella flexneri and the Autophagy Machinery

    OpenAIRE

    Krokowski, Sina; Mostowy, Serge

    2016-01-01

    Autophagy, an intracellular degradation process, is increasingly recognized as having important roles in host defense. Interactions between Shigella flexneri and the autophagy machinery were first discovered in 2005. Since then, work has shown that multiple autophagy pathways are triggered by S. flexneri, and autophagic responses can have different roles during Shigella infection. Here, we review the interactions between S. flexneri and the autophagy machinery, highlighting that studies using...

  19. Loss of autophagy enhances MIF/macrophage migration inhibitory factor release by macrophages.

    Science.gov (United States)

    Lee, Jacinta P W; Foote, Andrew; Fan, Huapeng; Peral de Castro, Celia; Lang, Tali; Jones, Sarah A; Gavrilescu, Nichita; Mills, Kingston H G; Leech, Michelle; Morand, Eric F; Harris, James

    2016-06-01

    MIF (macrophage migration inhibitory factor [glycosylation-inhibiting factor]) is a pro-inflammatory cytokine expressed in multiple cells types, including macrophages. MIF plays a pathogenic role in a number of inflammatory diseases and has been linked to tumor progression in some cancers. Previous work has demonstrated that loss of autophagy in macrophages enhances secretion of IL1 family cytokines. Here, we demonstrate that loss of autophagy, by pharmacological inhibition or siRNA silencing of Atg5, enhances MIF secretion by monocytes and macrophages. We further demonstrate that this is dependent on mitochondrial reactive oxygen species (ROS). Induction of autophagy with MTOR inhibitors had no effect on MIF secretion, but amino acid starvation increased secretion. This was unaffected by Atg5 siRNA but was again dependent on mitochondrial ROS. Our data demonstrate that autophagic regulation of mitochondrial ROS plays a pivotal role in the regulation of inflammatory cytokine secretion in macrophages, with potential implications for the pathogenesis of inflammatory diseases and cancers. PMID:27163877

  20. Autophagy counteracts apoptosis in human multiple myeloma cells exposed to oridonin in vitro via regulating intracellular ROS and SIRT1

    Institute of Scientific and Technical Information of China (English)

    Rong ZENG; Yan CHEN; Shuai ZHAO; Guo-hui CUI

    2012-01-01

    To explore the mechanisms underlying the oridonin-induced apoptosis and autophagy in human multiple myeloma cells in vitro.Methods:Human multiple myeloma RPMI8266 cells were used.The cell viability was assessed using MTT assay.Morphological changes of apoptosis and autophagy were observed under transmission electron microscope.TUNEL and annexin V-FITC/PI dual staining assays were used to measure apoptosis.Autophagy was analyzed using Western blot analysis and immunofluorescence staining with a QDs605 nm-Anti-LC3 fluorescent probe.Intracellular ROS was estimated with flow cytometry using DCFH-DA fluorescent probe.Protein levels of active caspase 3,Beclin 1 and SIRT1 were determined with Western blot analysis.Results:Exposure to oridonin (1-64 μmol/L) inhibited the proliferation of RPMI8266 cells in a concentration-dependent manner with an IC50 value of 6.74 μmol/L.Exposure to oridonin (7 μmol/L) simultaneously induced caspase 3-mediated apoptosis and Beclin 1-dependent autophagy of RPMI8266 cells.Both the apoptosis and autophagy were time-dependent,and apoptosis was the main effector pathway of cell death.Exposure to oridonin (7 μmol/L) increased intracellular ROS and reduced SIRT1 nuclear protein in a time-dependent manner.The blockade of intracellular generation of ROS by NAC (5 mmol/L) abrogated apoptosis,autophagy and the decrease of SIRT1 in the cells exposed to oridonin (7 μmol/L).The inhibition of autophagy by 3-MA (5 mmol/L) sensitized the cells to oridonin-induced apoptosis,which was accompanied by increased intracellular ROS and decreased SlRT1.Conclusion:Oridonin simultaneously induces apoptosis and autophagy of human multiple myeloma RPMI8266 cells via regulation of intracellular ROS generation and SIRT1 nuclear protein.The cytotoxicity of oridonin is mainly mediated through the apoptotic pathway,whereas the autophagy protects the cells from apoptosis.

  1. Synergistic effect of natural compounds on the fatty acid-induced autophagy of activated hepatic stellate cells.

    Science.gov (United States)

    Lee, Kuan-Wei; Thiyagarajan, Varadharajan; Sie, Huei-Wun; Cheng, Ming-Fan; Tsai, May-Jywan; Chia, Yi-Chen; Weng, Ching-Feng

    2014-09-01

    Autophagy, a lysosomal pathway to maintain cellular homeostasis, is mediated via the mammalian target of rapamycin (mTOR)-dependent pathways. Hepatic stellate cells (HSCs), previously termed fat- or vitamin A-storing cells, can transdifferentiate into myofibroblast-like cells and are the most relevant cell type for overproduction of extracellular matrix (ECM) and development of liver fibrosis during injury. However, the role of autophagy in fat metabolism of HSCs remains unclear. This study investigates the regulatory effect of natural compounds on fatty acid-induced autophagy pathways of nonchemical-induced HSC (NHSC) and thioacetamide-induced HSC. Oleic acid (OA) and palmitic acid (PA) have shown a significant effect on cell proliferation with oil red O staining and Western blot confirming that OA and PA induce fat storage ability and autophagy protein expression in NHSC. Natural compounds rutin, curcumin, antroquinonol and benzyl cinnamate treatment have shown no effect on the autophagy protein expression. Nevertheless, cells pretreated with OA and PA then treated with rutin, curcumin, antroquinonol and benzyl cinnamate could significantly induce the light chain I/II (LC3 I/II) protein expression. In mTOR-dependent pathway, the PI3K-Class I, Akt, and p-mTOR proteins were decreased with PA treatment. However, there were no significant changes in PI3K-Class III and Beclin-1 protein expressions found to imply that this autophagy is unrelated to the mTOR-independent pathway. Taken together, the present study unveils rutin and curcumin as a possible effective stimulation for fatty acid-induced autophagy via mTOR-dependent pathways in NHSC. We further suggest the benefits of these natural compounds for alleviating liver fibrosis. PMID:24857031

  2. Caspase dependence of the death of neonatal retinal ganglion cells induced by axon damage and induction of autophagy as a survival mechanism

    Directory of Open Access Journals (Sweden)

    C. Sternberg

    2010-10-01

    Full Text Available We examined the degeneration of post-mitotic ganglion cells in ex-vivo neonatal retinal explants following axon damage. Ultrastructural features of both apoptosis and autophagy were detected. Degenerating cells reacted with antibodies specific for activated caspase-3 or -9, consistent with the presence of caspase activity. Furthermore, peptidic inhibitors of caspase-9, -6 or -3 prevented cell death (100 µM Ac-LEDH-CHO, 50 µM Ac-VEID-CHO and 10 µM Z-DEVD-fmk, respectively. Interestingly, inhibition of autophagy by 7-10 mM 3-methyl-adenine increased the rate of cell death. Immunohistochemistry data, caspase activation and caspase inhibition data suggest that axotomy of neonatal retinal ganglion cells triggers the intrinsic apoptotic pathway, which, in turn, is counteracted by a pro-survival autophagic response, demonstrated by electron microscopy profiles and pharmacological autophagy inhibitor.

  3. Autophagy and Retromer Components in Plant Innate Immunity

    DEFF Research Database (Denmark)

    Munch, David

    -hormone salicylic acid. Here, I present data that make it clear that NPR1 does not directly regulate autophagy, but instead control stress responses that indirectly activate autophagy. The observations presented will also clarify why autophagy has been described as being both a pro-death and pro-life pathway under...

  4. Natural Products and Ion Channel Pharmacology

    OpenAIRE

    Teichert, Russell W.; Olivera, Baldomero M.

    2010-01-01

    An accelerated rate of natural-product discovery is critical for the future of ion channel pharmacology. For the full potential of natural products to be realized, an interdisciplinary initiative is required that combines chemical ecology and ion channel physiology. A prime source of future drug leads targeted to ion channels is the vast assortment of compounds that mediate biotic interactions in the marine environment. Many animals have evolved a chemical strategy to change the behavior of t...

  5. Xeroderma Pigmentosum Group A Promotes Autophagy to Facilitate Cisplatin Resistance in Melanoma Cells through the Activation of PARP1.

    Science.gov (United States)

    Ge, Rui; Liu, Lin; Dai, Wei; Zhang, Weigang; Yang, Yuqi; Wang, Huina; Shi, Qiong; Guo, Sen; Yi, Xiuli; Wang, Gang; Gao, Tianwen; Luan, Qi; Li, Chunying

    2016-06-01

    Xeroderma pigmentosum group A (XPA), a key protein in the nucleotide excision repair pathway, has been shown to promote the resistance of tumor cells to chemotherapeutic drugs by facilitating the DNA repair process. However, the role of XPA in the resistance of melanoma to platinum-based drugs like cisplatin is largely unknown. In this study, we initially found that XPA was expressed at higher levels in cisplatin-resistant melanoma cells than in cisplatin-sensitive ones. Furthermore, the knockdown of XPA not only increased cellular apoptosis but also inhibited cisplatin-induced autophagy, which rendered the melanoma cells more sensitive to cisplatin. Moreover, we discovered that the increased XPA in resistant melanoma cells promoted poly(adenosine diphosphate-ribose) polymerase 1 (PARP1) activation and that the inhibition of PARP1 could attenuate the cisplatin-induced autophagy. Finally, we proved that the inhibition of PARP1 and the autophagy process made resistant melanoma cells more susceptible to cisplatin treatment. Our study shows that XPA can promote cell-protective autophagy in a DNA repair-independent manner by enhancing the activation of PARP1 in melanoma cells resistant to cisplatin and that the XPA-PARP1-mediated autophagy process can be targeted to overcome cisplatin resistance in melanoma chemotherapy. PMID:26880244

  6. Exercise induces autophagy in peripheral tissues and in the brain

    OpenAIRE

    He, Congcong; Sumpter, Jr., Rhea; Levine, Beth

    2012-01-01

    We recently identified physical exercise as a newly defined inducer of autophagy in vivo. Exercise induced autophagy in multiple organs involved in metabolic regulation, such as muscle, liver, pancreas and adipose tissue. To study the physiological role of exercise-induced autophagy, we generated mice with a knock-in nonphosphorylatable mutation in BCL2 (Thr69Ala, Ser70Ala and Ser84Ala) (BCL2 AAA) that are defective in exercise- and starvation-induced autophagy but not in basal autophagy. We ...

  7. Autophagy in the light of sphingolipid metabolism

    DEFF Research Database (Denmark)

    Harvald, Eva Bang; Olsen, Anne Sofie Braun; Færgeman, Nils J.

    2015-01-01

    Maintenance of cellular homeostasis requires tight and coordinated control of numerous metabolic pathways, which are governed by interconnected networks of signaling pathways and energy-sensing regulators. Autophagy, a lysosomal degradation pathway by which the cell self-digests its own components......, has over the past decade been recognized as an essential part of metabolism. Autophagy not only rids the cell of excessive or damaged organelles, misfolded proteins, and invading microorganisms, it also provides nutrients to maintain crucial cellular functions. Besides serving as essential structural...... moieties of biomembranes, lipids including sphingolipids are increasingly being recognized as central regulators of a number of important cellular processes, including autophagy. In the present review we describe how sphingolipids, with special emphasis on ceramides and sphingosine-1-phosphate, can act as...

  8. Pharmacologic Therapies in Anticoagulation.

    Science.gov (United States)

    Ferreira, Joana Lima; Wipf, Joyce E

    2016-07-01

    Anticoagulants are beneficial for prevention and treatment of venous thromboembolism and stroke prevention in atrial fibrillation. The development of target-specific oral anticoagulants is changing the landscape of anticoagulation therapy and created growing interest on this subject. Understanding the pharmacology of different anticoagulants is the first step to adequately treat patients with best available therapy while avoiding serious bleeding complications. This article reviews the pharmacology of the main anticoagulant classes (vitamin K antagonists, direct oral anticoagulants, and heparins) and their clinical indications based on evidence-based data currently available in the literature. PMID:27235611

  9. Autophagy protects type II alveolar epithelial cells from Mycobacterium tuberculosis infection

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Xu-Guang [Center for Clinical Laboratory Medicine of PLA, Xijing Hospital, Fourth Military Medical University, Xi' an (China); Department of Laboratory Medicine, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou (China); Ji, Tian-Xing [Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou (China); Xia, Yong, E-mail: gysyxy@gmail.com [Center for Clinical Laboratory Medicine of PLA, Xijing Hospital, Fourth Military Medical University, Xi' an (China); Ma, Yue-Yun, E-mail: cmbmayy@fmmu.edu.cn [Center for Clinical Laboratory Medicine of PLA, Xijing Hospital, Fourth Military Medical University, Xi' an (China)

    2013-03-08

    Highlights: ► We investigated the protective effect of autophagy pathway against MTB infection. ► MTB-infected A549 cells had higher LDH release. ► Inhibition of autophagy signaling significantly enhanced the MTB-induced necrosis. ► Autophagy prevents apoptosis and promotes cell survival in infected cells. -- Abstract: This study was designed to investigate the protective effect of the autophagy signaling pathway against Mycobacterium tuberculosis infection in type II alveolar epithelial cells. An in vitro M. tuberculosis system was established using human A549 cells. Infection-induced changes in the expression of the autophagic marker LC3 were assessed by reverse transcription-PCR and Western blotting. Morphological changes in autophagosomes were detected by transmission electron microscopy (TEM). The function of the autophagy signaling pathway during infection was assessed by measuring the level of cell death and the amount of lactate dehydrogenase (LDH) released in the presence or absence of the inhibitor 3-methyladenine (3-MA). In addition, effects on LDH release were assessed after the siRNA-mediated knockdown of the essential autophagosomal structural membrane protein Atg5. LC3 mRNA expression was significantly reduced in M.tuberculosis-infected A549 cells (16888.76 ± 1576.34 vs. uninfected: 12744.29 ± 1089.37; P < 0.05). TEM revealed M.tuberculosis bacilli-containing compartments that were surrounded by double membranes characteristic of the autophagic process. M.tuberculosis-infected A549 cells released more LDH (1.45 ± 0.12 vs. uninfected: 0.45 ± 0.04; P < 0.05). The inhibition of autophagy signaling significantly enhanced M.tuberculosis-induced necrosis (3-MA: 75 ± 5% vs. untreated: 15 ± 1%; P < 0.05) and LDH release (3-MA: 2.50 ± 0.24 vs. untreated: 0.45 ± 0.04; Atg5 knockdown: 3.19 ± 0.29 vs. untreated: 1.28 ± 0.11; P < 0.05). Our results indicate that autophagy signaling pathway prevents apoptosis in type II alveolar epithelial cells

  10. Autophagy protects type II alveolar epithelial cells from Mycobacterium tuberculosis infection

    International Nuclear Information System (INIS)

    Highlights: ► We investigated the protective effect of autophagy pathway against MTB infection. ► MTB-infected A549 cells had higher LDH release. ► Inhibition of autophagy signaling significantly enhanced the MTB-induced necrosis. ► Autophagy prevents apoptosis and promotes cell survival in infected cells. -- Abstract: This study was designed to investigate the protective effect of the autophagy signaling pathway against Mycobacterium tuberculosis infection in type II alveolar epithelial cells. An in vitro M. tuberculosis system was established using human A549 cells. Infection-induced changes in the expression of the autophagic marker LC3 were assessed by reverse transcription-PCR and Western blotting. Morphological changes in autophagosomes were detected by transmission electron microscopy (TEM). The function of the autophagy signaling pathway during infection was assessed by measuring the level of cell death and the amount of lactate dehydrogenase (LDH) released in the presence or absence of the inhibitor 3-methyladenine (3-MA). In addition, effects on LDH release were assessed after the siRNA-mediated knockdown of the essential autophagosomal structural membrane protein Atg5. LC3 mRNA expression was significantly reduced in M.tuberculosis-infected A549 cells (16888.76 ± 1576.34 vs. uninfected: 12744.29 ± 1089.37; P < 0.05). TEM revealed M.tuberculosis bacilli-containing compartments that were surrounded by double membranes characteristic of the autophagic process. M.tuberculosis-infected A549 cells released more LDH (1.45 ± 0.12 vs. uninfected: 0.45 ± 0.04; P < 0.05). The inhibition of autophagy signaling significantly enhanced M.tuberculosis-induced necrosis (3-MA: 75 ± 5% vs. untreated: 15 ± 1%; P < 0.05) and LDH release (3-MA: 2.50 ± 0.24 vs. untreated: 0.45 ± 0.04; Atg5 knockdown: 3.19 ± 0.29 vs. untreated: 1.28 ± 0.11; P < 0.05). Our results indicate that autophagy signaling pathway prevents apoptosis in type II alveolar epithelial cells

  11. What to Eat: Evidence for Selective Autophagy in Plants

    Institute of Scientific and Technical Information of China (English)

    Brice E.Floyd; Stephanie C.Morriss; Gustavo C.Maclntosh; Diane C.Bassham

    2012-01-01

    Autophagy is a macromolecular degradation pathway by which cells recycle their contents as a developmental process,house-keeping mechanism,and response to environmental stress.In plants,autophagy involves the sequestration of cargo to be degraded,transport to the cell vacuole in a double-membrane bound autophagosome,and subsequent degradation by lytic enzymes.Autophagy has generally been considered to be a non-selective mechanism of degradation.However,studies in yeast and animals have found numerous examples of selective autophagy,with cargo including proteins,protein aggregates,and organelles.Recent work has also provided evidence for several types of selective autophagy in plants.The degradation of protein aggregates was the first selective autophagy described in plants,and,more recently,a hybrid protein of the mammalian selective autophagy adaptors p62 and NBR1,which interacts with the autophagy machinery and may function in autophagy of protein aggregates,was described in plants.Other intracellular components have been suggested to be selectively targeted by autophagy in plants,but the current evidence is limited.Here,we discuss recent findings regarding the selective targeting of cell components by autophagy in plants.

  12. Induction of autophagy improves embryo viability in cloned mouse embryos

    Science.gov (United States)

    Shen, XingHui; Zhang, Na; Wang, ZhenDong; Bai, GuangYu; Zheng, Zhong; Gu, YanLi; Wu, YanShuang; Liu, Hui; Zhou, DongJie; Lei, Lei

    2015-01-01

    Autophagy is an essential cellular mechanism that degrades cytoplasmic proteins and organelles to recycle their components. Moreover, autophagy is essential for preimplantation development in mammals. Here we show that autophagy is also important for reprogramming in somatic cell nuclear transfer (SCNT). Our data indicate that unlike fertilized oocytes, autophagy is not triggered in SCNT embryos during 6 hours of activation. Mechanistically, the inhibited autophagic induction during SCNT activation is due to the cytochalasin B (CB) caused depolymerization of actin filaments. In this study, we induced autophagy during SCNT activation by rapamycin and pp242, which could restore the expected level of autophagy and significantly enhance the development of SCNT embryos to the blastocyst stage when compared with the control (68.5% and 68.7% vs. 41.5%, P autophagy is important for development of SCNT embryos and inhibited autophagic induction during SCNT activation might be one of the serious causes of low efficiency of SCNT. PMID:26643778

  13. Autophagy: A double-edged sword in intervertebral disk degeneration.

    Science.gov (United States)

    Zhang, Shu-Jun; Yang, Wei; Wang, Cheng; He, Wen-Si; Deng, Hai-Yang; Yan, Yi-Guo; Zhang, Jian; Xiang, Yong-Xiao; Wang, Wen-Jun

    2016-06-01

    Autophagy is a homeostatic mechanism through which intracellular damaged organelles and proteins are degraded and recycled in response to increased metabolic demands or stresses. Although primarily cytoprotective, dysfunction of autophagy is often associated with many degenerative diseases, including intervertebral disc (IVD) degeneration (IDD). As a main contributing factor to low back pain, IDD is the pathological basis for various debilitating spinal diseases. Either higher or lower levels of autophagy are observed in degenerative IVD cells. Despite the precise role of autophagy in disc degeneration that is still controversial, with difference from protection to aggravation, targeting autophagy has shown promise for mitigating disc degeneration. In the current review, we summarize the changes of autophagy in degenerative IVD cells and mainly discuss the relationship between autophagy and IDD. With continued efforts, modulation of the autophagic process could be a potential and attractive therapeutic strategy for degenerative disc disease. PMID:27018178

  14. mTOR Overactivation and Compromised Autophagy in the Pathogenesis of Pulmonary Fibrosis.

    Directory of Open Access Journals (Sweden)

    Yao-Song Gui

    Full Text Available The mammalian target of rapamycin (mTOR signaling pathway in pulmonary fibrosis was investigated in cell and animal models. mTOR overactivation in alveolar epithelial cells (AECs was achieved in the conditional and inducible Tsc1 knock-down mice SPC-rtTA/TetO-Cre/Tsc1(fx/+ (STT. Doxycycline caused Tsc1 knock-down and consequently mTOR activation in AECs for the STT mice. Mice treated with bleomycin exhibited increased mortality and pulmonary fibrosis compared with control mice. In wild-type C57BL/6J mice, pretreatment with rapamycin attenuated the bleomycin-mediated mortality and fibrosis. Rapamycin-mediated mouse survival benefit was inhibited by chloroquine, an autophagy inhibitor. Autophagosomes were decreased in the lungs after bleomycin exposure. Rapamycin induced the production of autophagosomes and diminished p62. We concluded that mTOR overactivation in AECs and compromised autophagy in the lungs are involved in the pathogenesis of pulmonary fibrosis. The suppression of mTOR and enhancement of autophagy may be used for treatment of pulmonary fibrosis.

  15. Social Pharmacology: Expanding horizons

    Directory of Open Access Journals (Sweden)

    Rituparna Maiti

    2014-01-01

    Full Text Available In the current modern and global society, social changes are in constant evolution due to scientific progress (technology, culture, customs, and hygiene and produce the freedom in individuals to take decisions by themselves or with their doctors toward drug consumption. In the arena of marketed drug products which includes society, individual, administration, and pharmaceutical industry, the young discipline emerged is social pharmacology or sociopharmacology. This science arises from clinical pharmacology, and deals with different parameters, which are important in creating knowledge on marketed drugs. However, the scope of "social pharmacology" is not covered by the so-called "Phase IV" alone, but it is the science that handles the postmarketing knowledge of drugs. The social pharmacology studies the "life cycle" of any marketed pharmaceutical product in the social terrain, and evaluates the effects of the real environment under circumstances totally different in the drug development process. Therefore, there are far-reaching horizons, plural, and shared predictions among health professionals and other, for beneficial use of a drug, toward maximizing the benefits of therapy, while minimizing negative social consequences.

  16. Developmental paediatric anaesthetic pharmacology

    DEFF Research Database (Denmark)

    Hansen, Tom Giedsing

    2015-01-01

    Safe and effective drug therapy in neonates, infants and children require detailed knowledge about the ontogeny of drug disposition and action as well how these interact with genetics and co-morbidity of children. Recent advances in developmental pharmacology in children follow the increased...

  17. WT1 is involved in the Akt-JNK pathway dependent autophagy through directly regulating Gas1 expression in human osteosarcoma cells.

    Science.gov (United States)

    Mo, Hao; He, Juliang; Yuan, Zhenchao; Mo, Ligen; Wu, Zhenjie; Lin, Xiang; Liu, Bin; Guan, Jian

    2016-09-01

    Macroautophagy (herein termed autophagy) works as a protective mechanism in tumorigenesis and development under metabolic stress condition. Multitudes of genes have been found involved in this process during past decades. In the present study, we report that Wilm's tumor suppressor1 (WT1) is involved in autophagy in osteosarcoma (OS) cells. WT1, a transcription factor with multitude of target genes, expresses in a majority of cancer types. Though wide-ranging effect of WT1 is now well documented, the function of WT1 in tumors remains poorly defined. In this chapter, it is found that high expression of WT1 positively correlates with active autophagy in human osteosarcoma cells. And further study on cell signaling pathway illustrates that Akt/JNK pathway acts as a positive regulator of autophagy induced by WT1. Here, we present evidence that WT1 modulates Akt/JNK signaling pathway mediated autophagy by controlling the expression of growth arrest-specific 1 (Gas1). We show that WT1 is required for Gas1 transcription in osteosarcoma cells. And Gas1 is upregulated followed WT1 overexpression in a time-dependent manner. Loss of Gas1 results in a reduction of WT1-induced autophagy. PMID:27453337

  18. Plac8 Links Oncogenic Mutations to Regulation of Autophagy and Is Critical to Pancreatic Cancer Progression

    Directory of Open Access Journals (Sweden)

    Conan Kinsey

    2014-05-01

    Full Text Available Mutations in p53 and RAS potently cooperate in oncogenic transformation, and correspondingly, these genetic alterations frequently coexist in pancreatic ductal adenocarcinoma (PDA and other human cancers. Previously, we identified a set of genes synergistically activated by combined RAS and p53 mutations as frequent downstream mediators of tumorigenesis. Here, we show that the synergistically activated gene Plac8 is critical for pancreatic cancer growth. Silencing of Plac8 in cell lines suppresses tumor formation by blocking autophagy, a process essential for maintaining metabolic homeostasis in PDA, and genetic inactivation in an engineered mouse model inhibits PDA progression. We show that Plac8 is a critical regulator of the autophagic machinery, localizing to the lysosomal compartment and facilitating lysosome-autophagosome fusion. Plac8 thus provides a mechanistic link between primary oncogenic mutations and the induction of autophagy, a central mechanism of metabolic reprogramming, during PDA progression.

  19. Fluoxetine induces cytotoxic endoplasmic reticulum stress and autophagy in triple negative breast cancer

    Science.gov (United States)

    Bowie, Michelle; Pilie, Patrick; Wulfkuhle, Julia; Lem, Siya; Hoffman, Abigail; Desai, Shraddha; Petricoin, Emanuel; Carter, Amira; Ambrose, Adrian; Seewaldt, Victoria; Yu, Dihua; Ibarra Drendall, Catherine

    2015-01-01

    AIM: To investigate the mechanism of action of lipophilic antidepressant fluoxetine (FLX) in representative molecular subtypes of breast cancer. METHODS: The anti-proliferative effects and mechanistic action of FLX in triple-negative (SUM149PT) and luminal (T47D and Au565) cancer cells and non-transformed MCF10A were investigated. Reverse phase protein microarray (RPPM) was performed with and without 10 μmol/L FLX for 24 and 48 h to determine which proteins are significantly changed. Viability and cell cycle analysis were also performed to determine drug effects on cell growth. Western blotting was used to confirm the change in protein expression examined by RPPM or pursue other signaling proteins. RESULTS: The FLX-induced cell growth inhibition in all cell lines was concentration- and time-dependent but less pronounced in early passage MCF10A. In comparison to the other lines, cell growth reduction in SUM149PT coincided with significant induction of endoplasmic reticulum (ER) stress and autophagy after 24 and 48 h of 10 μmol/L FLX, resulting in decreased translation of proteins along the receptor tyrosine kinase/Akt/mammalian target of rapamycin pathways. The increase in autophagy marker, cleaved microtubule-associated protein 1 light chain 3, in SUM149PT after 24 h of FLX was likely due to increased metabolic demands of rapidly dividing cells and ER stress. Consequently, the unfolded protein response mediated by double-stranded RNA-dependent protein kinase-like ER kinase resulted in inhibition of protein synthesis, growth arrest at the G1 phase, autophagy, and caspase-7-mediated cell death. CONCLUSION: Our study suggests a new role for FLX as an inducer of ER stress and autophagy, resulting in death of aggressive triple negative breast cancer SUM149PT. PMID:26677444

  20. Avermectin induced autophagy in pigeon spleen tissues.

    Science.gov (United States)

    Liu, Ci; Zhao, Yanbing; Chen, Lijie; Zhang, Ziwei; Li, Ming; Li, Shu

    2015-12-01

    The level of autophagy is considered as an indicator for monitoring the toxic impact of pesticide exposure. Avermectin (AVM), a widely used insecticide, has immunotoxic effects on the pigeon spleen. The aim of this study was to investigate the status of autophagy and the expression levels of microtubule-associated protein1 light chain 3 (LC3), beclin-1, dynein, autophagy associated gene (Atg) 4B, Atg5, target of rapamycin complex 1 (TORC1) and target of rapamycin complex 2 (TORC2) in AVM-treated pigeon spleens. Eighty two-month-old pigeons were randomly divided into four groups: a control group, a low-dose group, a medium-dose group and a high-dose group, which were fed a basal diet spiked with 0, 20, 40 and 60 mg AVM/kg diet, respectively. Microscopic cellular morphology revealed a significant increase in autophagic structures in the AVM-treated groups. The expression of LC3, beclin-1, dynein, Atg4B and Atg5 increased, while mRNA levels of TORC1 and TORC2 were decreased in the AVM-treated groups relative to the control groups at 30, 60 and 90 days in the pigeon spleen. These results indicated that AVM exposure could up-regulate the level of autophagy in a dose-time-dependent manner in the pigeon spleen. PMID:26541719

  1. MicroRNA regulation of Autophagy

    DEFF Research Database (Denmark)

    Frankel, Lisa B; Lund, Anders H

    2012-01-01

    progress has recently contributed to our understanding of the molecular mechanisms of the autophagy machinery, yet several gaps remain in our knowledge of this process. The discovery of microRNAs (miRNAs) established a new paradigm of post-transcriptional gene regulation and during the past decade these...

  2. Autophagy as a Potential Target for Sarcopenia.

    Science.gov (United States)

    Fan, Jingjing; Kou, Xianjuan; Jia, Shaohui; Yang, Xiaoqi; Yang, Yi; Chen, Ning

    2016-07-01

    Sarcopenia is an aging-related disease with a significant reduction in mass and strength of skeletal muscle due to the imbalance between protein synthesis and protein degradation. The loss of skeletal muscle is an inevitable event during aging process, which can result in the significant impact on the quality of life, and also can increase the risk for other aging-associated diseases in the elderly. However, the underlying molecular mechanism of aging-related skeletal muscle loss is still poorly understood. Autophagy is a degradation pathway for the clearance of dysfunctional organelles and damaged macromolecules during aging process. Appropriate induction or accurate regulation of autophagic process and improved quality control of mitochondria through autophagy or other strategies are required for the maintenance of skeletal muscle mass. In this article, we have summarized the current understanding of autophagic pathways in sarcopenia, and discussed the functional status of autophagy and autophagy-associated quality control of mitochondria in the pathogenesis of sarcopenia. Moreover, this article will provide some theoretical references for the exploration of scientific and optimal intervention strategies such as exercise and caloric restriction for the prevention and treatment of sarcopenia through the regulation of autophagic pathways. PMID:26580995

  3. Impairment of autophagy: From hereditary disorder to drug intoxication

    International Nuclear Information System (INIS)

    At first, the molecular mechanism of autophagy was unveiled in a unicellular organism Saccharomyces cerevisiae (budding yeast), followed by the discovery that the basic mechanism of autophagy is conserved in multicellular organisms including mammals. Although autophagy was considered to be a non-selective bulk protein degradation system to recycle amino acids during periods of nutrient starvation, it is also believed to be an essential mechanism for the selective elimination of proteins/organelles that are damaged under pathological conditions. Research advances made using autophagy-deficient animals have revealed that impairments of autophagy often underlie the pathogenesis of hereditary disorders such as Danon, Parkinson's, Alzheimer's, and Huntington's diseases, and amyotrophic lateral sclerosis. On the other hand, there are many reports that drugs and toxicants, including arsenic, cadmium, paraquat, methamphetamine, and ethanol, induce autophagy during the development of their toxicity on many organs including heart, brain, lung, kidney, and liver. Although the question as to whether autophagic machinery is involved in the execution of cell death or not remains controversial, the current view of the role of autophagy during cell/tissue injury is that it is an important, often essential, cytoprotective reaction; disturbances in cytoprotective autophagy aggravate cell/tissue injuries. The purpose of this review is to provide (1) a gross summarization of autophagy processes, which are becoming more important in the field of toxicology, and (2) examples of important studies reporting the involvement of perturbations in autophagy in cell/tissue injuries caused by acute as well as chronic intoxication

  4. Induction of cytoprotective autophagy in PC-12 cells by cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qiwen [College of Veterinary Medicine, Yangzhou University, Yangzhou 225009 (China); Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009 (China); Bijie Pilot Area Research Institute of Bijie University, Bijie 551700 (China); Zhu, Jiaqiao; Zhang, Kangbao; Jiang, Chenyang; Wang, Yi; Yuan, Yan; Bian, Jianchun; Liu, Xuezhong; Gu, Jianhong [College of Veterinary Medicine, Yangzhou University, Yangzhou 225009 (China); Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009 (China); Liu, Zongping, E-mail: liuzongping@yzu.edu.cn [College of Veterinary Medicine, Yangzhou University, Yangzhou 225009 (China); Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009 (China)

    2013-08-16

    Highlights: •Cadmium can promote early upregulation of autophagy in PC-12 cells. •Autophagy precedes apoptosis in cadmium-treated PC-12 cells. •Cadmium-induced autophagy is cytoprotective in PC-12 cells. •Class III PI3K/beclin-1/Bcl-2 signaling pathway plays a positive role in cadmium-triggered autophagy. -- Abstract: Laboratory data have demonstrated that cadmium (Cd) may induce neuronal apoptosis. However, little is known about the role of autophagy in neurons. In this study, cell viability decreased in a dose- and time-dependent manner after treatment with Cd in PC-12 cells. As cells were exposed to Cd, the levels of LC3-II proteins became elevated, specific punctate distribution of endogenous LC3-II increased, and numerous autophagosomes appeared, which suggest that Cd induced a high level of autophagy. In the late stages of autophagy, an increase in the apoptosis ratio was observed. Likewise, pre-treatment with chloroquine (an autophagic inhibitor) and rapamycin (an autophagic inducer) resulted in an increased and decreased percentage of apoptosis in contrast to other Cd-treated groups, respectively. The results indicate that autophagy delayed apoptosis in Cd-treated PC-12 cells. Furthermore, co-treatment of cells with chloroquine reduced autophagy and cell activity. However, rapamycin had an opposite effect on autophagy and cell activity. Moreover, class III PI3 K/beclin-1/Bcl-2 signaling pathways served a function in Cd-induced autophagy. The findings suggest that Cd can induce cytoprotective autophagy by activating class III PI3 K/beclin-1/Bcl-2 signaling pathways. In sum, this study strongly suggests that autophagy may serve a positive function in the reduction of Cd-induced cytotoxicity.

  5. Induction of cytoprotective autophagy in PC-12 cells by cadmium

    International Nuclear Information System (INIS)

    Highlights: •Cadmium can promote early upregulation of autophagy in PC-12 cells. •Autophagy precedes apoptosis in cadmium-treated PC-12 cells. •Cadmium-induced autophagy is cytoprotective in PC-12 cells. •Class III PI3K/beclin-1/Bcl-2 signaling pathway plays a positive role in cadmium-triggered autophagy. -- Abstract: Laboratory data have demonstrated that cadmium (Cd) may induce neuronal apoptosis. However, little is known about the role of autophagy in neurons. In this study, cell viability decreased in a dose- and time-dependent manner after treatment with Cd in PC-12 cells. As cells were exposed to Cd, the levels of LC3-II proteins became elevated, specific punctate distribution of endogenous LC3-II increased, and numerous autophagosomes appeared, which suggest that Cd induced a high level of autophagy. In the late stages of autophagy, an increase in the apoptosis ratio was observed. Likewise, pre-treatment with chloroquine (an autophagic inhibitor) and rapamycin (an autophagic inducer) resulted in an increased and decreased percentage of apoptosis in contrast to other Cd-treated groups, respectively. The results indicate that autophagy delayed apoptosis in Cd-treated PC-12 cells. Furthermore, co-treatment of cells with chloroquine reduced autophagy and cell activity. However, rapamycin had an opposite effect on autophagy and cell activity. Moreover, class III PI3 K/beclin-1/Bcl-2 signaling pathways served a function in Cd-induced autophagy. The findings suggest that Cd can induce cytoprotective autophagy by activating class III PI3 K/beclin-1/Bcl-2 signaling pathways. In sum, this study strongly suggests that autophagy may serve a positive function in the reduction of Cd-induced cytotoxicity

  6. Hexokinase II inhibitor, 3-BrPA induced autophagy by stimulating ROS formation in human breast cancer cells.

    Science.gov (United States)

    Zhang, Qianwen; Zhang, Yuanyuan; Zhang, Pei; Chao, Zhenhua; Xia, Fei; Jiang, Chenchen; Zhang, Xudong; Jiang, Zhiwen; Liu, Hao

    2014-03-01

    Hexokinase II (HKII), a key enzyme of glycolysis, is widely over-expressed in cancer cells. 3-bromopyruvate (3-BrPA), an inhibitor of HK II, has been proposed as a specific antitumor agent. Autophagy is a process that regulates the balance between protein synthesis and protein degradation. Autophagy in mammalian systems occurs under basal conditions and can be stimulated by stresses, including starvation, oxidative stress. Therefore, we hypothesized that 3-BrPA could induce autophagy. In the present study, we explored the mechanism of 3-BrPA and its combined action with chloroquine. Our results demonstrate that in MDA-MB-435 and in MDA-MB-231 cells, 3-BrPA induces autophagy, which can be inhibited by chloroquine. Furthermore, the combined treatment synergistically decreased the number of viable cells. Interestingly, the combined treatment triggered apoptosis in MDA-MB-435 cells, while it induced necroptosis in MDA-MB-231 cells. ROS mediated cell death when 3-BrPA and CQ were co-administered. Finally, CQ enhanced the anticancer efficacy of 3-BrPA in vivo. Collectively, our results show that 3-BrPA triggers autophagy, increasing breast cancer cell resistance to 3-BrPA treatment and that CQ enhanced 3-BrPA-induced cell death in breast cancer cells by stimulating ROS formation. Thus, inhibition of autophagy may be an innovative strategy for adjuvant chemotherapy of breast cancer.human skeletal muscle. Efficient Mirk depletion in SU86.86 pancreatic cancer cells by an inducible shRNA decreased expression of eight antioxidant genes. Thus both cancer cells and differentiated myotubes utilize Mirk kinase to relieve oxidative stress. PMID:25053988

  7. Quercitrin treatment protects endothelial progenitor cells from oxidative damage via inducing autophagy through extracellular signal-regulated kinase.

    Science.gov (United States)

    Zhi, Kangkang; Li, Maoquan; Bai, Jun; Wu, Yongfa; Zhou, Sili; Zhang, Xiaoping; Qu, Lefeng

    2016-07-01

    Atherosclerosis is a disease resulting from impaired endothelial function, often caused by oxidant injury or inflammation. Endothelial progenitor cells (EPCs) play a critical role in repairing damaged endothelium and protecting against atherosclerosis. Quercitrin, a plant-derived flavonoid compound, displays antioxidant and anti-inflammatory activities. In this study, we showed that quercitrin treatment reduced the apoptosis of EPCs caused by oxidized low-density lipoprotein (ox-LDL) in a dose-dependent manner. Quercitrin improved tube formation, migration and adhesion of ox-LDL-treated EPCs. To determine the effect of quercitrin in vivo, EPCs treated with or without ox-LDL and quercitrin were locally injected into the ischemic hind limb muscle of nude mice. Those injected with EPCs treated with ox-LDL and quercitrin showed significantly increased local accumulation of EPCs, blood flow recovery and capillary density compared with the control and ox-LDL only groups. Furthermore, we showed that quercitrin enhanced autophagy and upregulated mitogen-activated protein kinase and ERK phosphorylation in a dose-dependent manner in vitro. Autophagy inhibitors, chloroquine and 3-methyladenine, abrogated quercitrin-enhanced autophagy caused by ox-LDL as evidenced by decreased numbers of branch points, migratory cells and adherent cells, and increased numbers of apoptotic cells. The ERK inhibitor PD98059 abrogated quercitrin-enhanced autophagy, as identified by decreased autophagosome formation and downregulated ERK phosphorylation. The inhibition of ERK did not affect the expression of Rac1, but enhanced phosphorylation of Akt. Quercitrin treatment also increased the expression of E-cadherin, and PD98059 abrogated the upregulation of E-cadherin induced by quercitrin. Our findings suggested that autophagy is a protective mechanism in EPCs exposed to oxidative damage. Quercitrin can promote autophagy through the activation of ERK and the ERK signaling pathway is therefore

  8. Pharmacology of Iron Transport

    OpenAIRE

    Byrne, Shaina L.; Krishnamurthy, Divya; Wessling-Resnick, Marianne

    2012-01-01

    Elucidating the molecular basis for the regulation of iron uptake, storage, and distribution is necessary to understand iron homeostasis. Pharmacological tools are emerging to identify and distinguish among different iron transport pathways. Stimulatory or inhibitory small molecules with effects on iron uptake can help characterize the mechanistic elements of iron transport and the roles of the transporters involved in these processes. In particular, iron chelators can serve as potential phar...

  9. Overview of safety pharmacology.

    Science.gov (United States)

    Goineau, Sonia; Lemaire, Martine; Froget, Guillaume

    2013-01-01

    Safety pharmacology entails the assessment of the potential risks of novel pharmaceuticals for human use. As detailed in the ICH S7A guidelines, safety pharmacology for drug discovery involves a core battery of studies on three vital systems: central nervous (CNS), cardiovascular (CV), and respiratory. Primary CNS studies are aimed at defining compound effects on general behavior, locomotion, neuromuscular coordination, seizure threshold, and vigilance. The primary CV test battery includes an evaluation of proarrhythmic risk using in vitro tests (hERG channel and Purkinje fiber assays) and in vivo measurements in conscious animals via telemetry. Comprehensive cardiac risk assessment also includes full hemodynamic evaluation in a large, anesthetized animal. Basic respiratory function can be examined in conscious animals using whole-body plethysmography. This allows for an assessment of whether the sensitivity to respiratory-depressant effects can be enhanced by exposure to increased CO2 . Other safety pharmacology topics detailed in this unit are the timing of such studies, ethical and animal welfare issues, and statistical evaluation. PMID:24510755

  10. Research Progression of Cellular Autophagy in Liver System Diseases

    Directory of Open Access Journals (Sweden)

    Chunyun Liu

    2013-09-01

    Full Text Available Autophagy is a basic biological phenomenon widely existed in eukaryotic cells and an important mechanism for cells to adjust to the surrounding environment, prevent invasion of pathogenic micro-organisms and maintain homeostasis, whose activity changes evidently in multiple liver system diseases, suggesting that there is close association between autophagy and the generation and development of liver system diseases. It is also reported that autophagy develops and exerts an important function in many liver-related diseases, such as hepatic carcinoma, non-alcoholic fatty liver disease, alcoholic liver disease, viral liver disease and acute liver injury. Therefore, this study aimed to summarize the relationship between autophagy and multiple liver diseases, hoping to explore the effect of autophagy in liver system diseases and further study the regulative effect of autophagy so as to provide new thoughts for their treatment.

  11. Nanomaterial-modulated autophagy: underlying mechanisms and functional consequences.

    Science.gov (United States)

    Zheng, Wei; Wei, Min; Li, Song; Le, Weidong

    2016-06-01

    Autophagy is an essential lysosome-dependent process that controls the quality of the cytoplasm and maintains cellular homeostasis, and dysfunction of this protein degradation system is correlated with various disorders. A growing body of evidence suggests that nanomaterials (NMs) have autophagy-modulating effects, thus predicting a valuable and promising application potential of NMs in the diagnosis and treatment of autophagy-related diseases. NMs exhibit unique physical, chemical and biofunctional properties, which may endow NMs with capabilities to modulate autophagy via various mechanisms. The present review highlights the impacts of various NMs on autophagy and their functional consequences. The possible underlying mechanisms for NM-modulated autophagy are also discussed. PMID:27193191

  12. WASH inhibits autophagy through suppression of Beclin 1 ubiquitination

    OpenAIRE

    Xia, Pengyan; Wang, Shuo; Du, Ying; Zhao, Zhenao; Shi, Lei; Sun, Lei; Huang, Guanling; Ye, Buqing; Li, Chong; Dai, Zhonghua; Hou, Ning; Cheng, Xuan; Sun, Qingyuan; Li, Lei(Beijing Institute of Petrochemical Technology, Beijing, 102617, People's Republic of China); Yang, Xiao

    2013-01-01

    Autophagy degrades cytoplasmic proteins and organelles to recycle cellular components that are required for cell survival and tissue homeostasis. However, it is not clear how autophagy is regulated in mammalian cells. WASH (Wiskott–Aldrich syndrome protein (WASP) and SCAR homologue) plays an essential role in endosomal sorting through facilitating tubule fission via Arp2/3 activation. Here, we demonstrate a novel function of WASH in modulation of autophagy. We show that WASH deficiency causes...

  13. Pyrvinium targets autophagy addiction to promote cancer cell death

    OpenAIRE

    Deng, Longfei; Lei, Yunlong; Liu, Rui; Li, Jingyi; Yuan, Kefei; Li, Yi; Chen, Yi; Liu, Yi; Lu, You; Edwards III, Carl K; Huang, Canhua; Wei, Yuquan

    2013-01-01

    Autophagy is a cellular catabolic process by which long-lived proteins and damaged organelles are degradated by lysosomes. Activation of autophagy is an important survival mechanism that protects cancer cells from various stresses, including anticancer agents. Recent studies indicate that pyrvinium pamoate, an FDA-approved antihelminthic drug, exhibits wide-ranging anticancer activity. Here we demonstrate that pyrvinium inhibits autophagy both in vitro and in vivo. We further demonstrate that...

  14. The interplay between autophagy and ROS in tumorigenesis

    Directory of Open Access Journals (Sweden)

    VassilikiKarantza

    2012-11-01

    Full Text Available Reactive oxygen species (ROS at physiological levels are important cell signaling molecules. However, aberrantly high ROS are intimately associated with disease and commonly observed in cancer. Mitochondria are primary sources of intracellular ROS, and their maintenance is essential to cellular health. Autophagy, an evolutionarily conserved process whereby cytoplasmic components are delivered to lysosomes for degradation, is responsible for mitochondrial turnover and removal of damaged mitochondria. Impaired autophagy is implicated in many pathological conditions, including neurological disorders, inflammatory bowel disease, diabetes, aging and cancer. The first reports connecting autophagy to cancer showed that allelic loss of the essential autophagy gene BECLIN1 (BECN1 is prevalent in human breast, ovarian and prostate cancers and that Becn1+/- mice develop mammary gland hyperplasias, lymphomas, and lung and liver tumors. Subsequent studies demonstrated that Atg5-/- and Atg7-/- livers give rise to adenomas, Atg4-/- mice are susceptible to chemical carcinogenesis, and Bif1-/- mice are prone to spontaneous tumors, indicating that autophagy defects promote tumorigenesis. Due to defective mitophagy, autophagy-deficient cells accumulate damaged mitochondria and deregulated ROS levels, which likely contribute to their tumor-initiating capacity. However, the role of autophagy in tumorigenesis is complex, as more recent work also revealed tumor dependence on autophagy: autophagy-competent mutant-Ras-expressing cells form tumors more efficiently than their autophagy-deficient counterparts; similarly, FIP200 deficiency suppresses PyMT-driven mammary tumorigenesis. These latter findings are attributed to the fact that tumors driven by powerful oncogenes have high metabolic demands catered to by autophagy. In this review, we discuss the relationship between ROS and autophagy and summarize our current knowledge on their functional interactions in

  15. Autophagy and mitophagy in the myocardium: therapeutic potential and concerns

    OpenAIRE

    Jimenez, Rebecca E; Kubli, Dieter A.; Gustafsson, Åsa B.

    2014-01-01

    The autophagic-lysosomal degradation pathway is critical for cardiac homeostasis, and defects in this pathway are associated with development of cardiomyopathy. Autophagy is responsible for the normal turnover of organelles and long-lived proteins. Autophagy is also rapidly up-regulated in response to stress, where it rapidly clears dysfunctional organelles and cytotoxic protein aggregates in the cell. Autophagy is also important in clearing dysfunctional mitochondria before they can cause ha...

  16. Grouping annotations on the subcellular layered interactome demonstrates enhanced autophagy activity in a recurrent experimental autoimmune uveitis T cell line.

    Directory of Open Access Journals (Sweden)

    Xiuzhi Jia

    Full Text Available Human uveitis is a type of T cell-mediated autoimmune disease that often shows relapse-remitting courses affecting multiple biological processes. As a cytoplasmic process, autophagy has been seen as an adaptive response to cell death and survival, yet the link between autophagy and T cell-mediated autoimmunity is not certain. In this study, based on the differentially expressed genes (GSE19652 between the recurrent versus monophasic T cell lines, whose adoptive transfer to susceptible animals may result in respective recurrent or monophasic uveitis, we proposed grouping annotations on a subcellular layered interactome framework to analyze the specific bioprocesses that are linked to the recurrence of T cell autoimmunity. That is, the subcellular layered interactome was established by the Cytoscape and Cerebral plugin based on differential expression, global interactome, and subcellular localization information. Then, the layered interactomes were grouping annotated by the ClueGO plugin based on Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases. The analysis showed that significant bioprocesses with autophagy were orchestrated in the cytoplasmic layered interactome and that mTOR may have a regulatory role in it. Furthermore, by setting up recurrent and monophasic uveitis in Lewis rats, we confirmed by transmission electron microscopy that, in comparison to the monophasic disease, recurrent uveitis in vivo showed significantly increased autophagy activity and extended lymphocyte infiltration to the affected retina. In summary, our framework methodology is a useful tool to disclose specific bioprocesses and molecular targets that can be attributed to a certain disease. Our results indicated that targeted inhibition of autophagy pathways may perturb the recurrence of uveitis.

  17. Autophagy in Lepidoptera: more than old wine in new bottle

    Directory of Open Access Journals (Sweden)

    G Tettamanti

    2011-01-01

    Full Text Available Autophagy is a cellular pathway that leads to the degradation of proteins and organelles. This process is usually involved in the maintenance of cell homeostasis when the organism experiences nutrient starvation, but in holometabolous insects autophagy also intervenes in the demolition of larval tissues and organs during metamorphosis. This review summarizes the current knowledge about autophagy research in Lepidoptera and discusses the use of moths and butterflies as models for tudying the roles and regulation of autophagy. It also gives insights into the cooperation between utophagy and apoptosis in cell death events that occur in lepidopteran in vivo and in vitro systems.

  18. Tracking autophagy during proliferation and differentiation of Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    William R. Proto

    2014-01-01

    Full Text Available Autophagy is a lysosome-dependent degradation mechanism that sequesters target cargo into autophagosomal vesicles. The Trypanosoma brucei genome contains apparent orthologues of several autophagy-related proteins including an ATG8 family. These ubiquitin-like proteins are required for autophagosome membrane formation, but our studies show that ATG8.3 is atypical. To investigate the function of other ATG proteins, RNAi compatible T. brucei were modified to function as autophagy reporter lines by expressing only either YFP-ATG8.1 or YFP-ATG8.2. In the insect procyclic lifecycle stage, independent RNAi down-regulation of ATG3 or ATG7 generated autophagy-defective mutants and confirmed a pro-survival role for autophagy in the procyclic form nutrient starvation response. Similarly, RNAi depletion of ATG5 or ATG7 in the bloodstream form disrupted autophagy, but did not impede proliferation. Further characterisation showed bloodstream form autophagy mutants retain the capacity to undergo the complex cellular remodelling that occurs during differentiation to the procyclic form and are equally susceptible to dihydroxyacetone-induced cell death as wild type parasites, not supporting a role for autophagy in this cell death mechanism. The RNAi reporter system developed, which also identified TOR1 as a negative regulator controlling YFP-ATG8.2 but not YFP-ATG8.1 autophagosome formation, will enable further targeted analysis of the mechanisms and function of autophagy in the medically relevant bloodstream form of T. brucei.

  19. Emerging role of selective autophagy in human diseases.

    Directory of Open Access Journals (Sweden)

    Kenji eMizumura

    2014-11-01

    Full Text Available AbstractAutophagy was originally described as a highly conserved system for the degradation of cytosol through a lysosome-dependent pathway. In response to starvation, autophagy degrades organelles and proteins to provide metabolites and energy for its pro-survival effects. Autophagy is recognized as playing a role in the pathogenesis of disease either directly or indirectly, through the regulation of vital processes such as programmed cell death, inflammation, and adaptive immune mechanisms. Recent studies have demonstrated that autophagy is not only a simple metabolite recycling system, but also has the ability to degrade specific cellular targets, such as mitochondria, cilia, and invading bacteria. In addition, selective autophagy has also been implicated in vesicle trafficking pathways, with potential roles in secretion and other intracellular transport processes. Selective autophagy has drawn the attention of researchers because of its potential importance in clinical diseases. Therapeutic strategies to target selective autophagy rather than general autophagy may maximize clinical benefit by enhancing selectivity. In this review, we outline the principle components of selective autophagy processes and their emerging importance in human disease, with an emphasis on pulmonary diseases.

  20. Regulation of autophagy by cytosolic acetyl-coenzyme A

    DEFF Research Database (Denmark)

    Mariño, Guillermo; Pietrocola, Federico; Eisenberg, Tobias;

    2014-01-01

    proteins, as well as the induction of autophagy, a homeostatic process of self-digestion. Multiple distinct manipulations designed to increase or reduce cytosolic AcCoA led to the suppression or induction of autophagy, respectively, both in cultured human cells and in mice. Moreover, maintenance of high Ac......CoA levels inhibited maladaptive autophagy in a model of cardiac pressure overload. Depletion of AcCoA reduced the activity of the acetyltransferase EP300, and EP300 was required for the suppression of autophagy by high AcCoA levels. Altogether, our results indicate that cytosolic AcCoA functions as a...

  1. Salinomycin induces autophagy in colon and breast cancer cells with concomitant generation of reactive oxygen species.

    Directory of Open Access Journals (Sweden)

    Berlinda Verdoodt

    Full Text Available BACKGROUND: Salinomycin is a polyether ionophore antibiotic that has recently been shown to induce cell death in human cancer cells displaying multiple mechanisms of drug resistance. The underlying mechanisms leading to cell death after salinomycin treatment have not been well characterized. We therefore investigated the role of salinomycin in caspase dependent and independent cell death in colon cancer (SW480, SW620, RKO and breast cancer cell lines (MCF-7, T47D, MDA-MB-453. METHODOLOGY/PRINCIPAL FINDINGS: We detected features of apoptosis in all cell lines tested, but the executor caspases 3 and 7 were only strongly activated in RKO and MDA-MB-453 cells. MCF-7 and SW620 cells instead presented features of autophagy such as cytoplasmic vacuolization and LC3 processing. Caspase proficient cell lines activated autophagy at lower salinomycin concentrations and before the onset of caspase activation. Salinomycin also led to the formation of reactive oxygen species (ROS eliciting JNK activation and induction of the transcription factor JUN. Salinomycin mediated cell death could be partially inhibited by the free radical scavenger N-acetyl-cysteine, implicating ROS formation in the mechanism of salinomycin toxicity. CONCLUSIONS: Our data indicate that, in addition to its previously reported induction of caspase dependent apoptosis, the initiation of autophagy is an important and early effect of salinomycin in tumor cells.

  2. Luteolin decreases the UVA‑induced autophagy of human skin fibroblasts by scavenging ROS.

    Science.gov (United States)

    Yan, Miaomiao; Liu, Zhongrong; Yang, Huilan; Li, Cuihua; Chen, Hulin; Liu, Yan; Zhao, Minling; Zhu, Yingjie

    2016-09-01

    Luteolin (LUT) is a flavone, which is universally present as a constituent of traditional Chinese herbs, and certain vegetables and spices, and has been demonstrated to exhibit potent radical scavenging and cytoprotective properties. Although LUT has various beneficial effects on health, the effects of LUT on the protection of skin remain to be fully elucidated. The present study investigated whether LUT can protect human skin fibroblasts (HSFs) from ultraviolet (UV) A irradiation. It was found that, following exposure to different doses of UVA irradiation, the HSFs exhibited autophagy, as observed by fluorescence and transmission electron microscopy, and reactive oxygen species (ROS) bursts, analyzed by flow cytometry, to differing degrees. Following incubation with micromolar concentrations of LUT, ROS production decreased and autophagy gradually declined. In addition, the expression of hypoxia‑inducible factor‑1α and the classical autophagy‑associated proteins, LC3 and Beclin 1 were observed by western blotting. Western blot analysis showed that the expression levels of HIF‑1α, LC3‑II and Beclin 1 gradually decreased in the UVA‑irradiated HSFs following treatment with LUT. These data indicated that UVA‑induced autophagy was mediated by ROS, suggesting the possibility of resistance against UV by certain natural antioxidants, including LUT. PMID:27430964

  3. Atorvastatin activates autophagy and promotes neurological function recovery after spinal cord injury

    Science.gov (United States)

    Gao, Shuang; Zhang, Zhong-ming; Shen, Zhao-liang; Gao, Kai; Chang, Liang; Guo, Yue; Li, Zhuo; Wang, Wei; Wang, Ai-mei

    2016-01-01

    Atorvastatin, a lipid-lowering medication, provides neuroprotective effects, although the precise mechanisms of action remain unclear. Our previous studies confirmed activated autophagy following spinal cord injury, which was conducive to recovery of neurological functions. We hypothesized that atorvastatin could also activate autophagy after spinal cord injury, and subsequently improve recovery of neurological functions. A rat model of spinal cord injury was established based on the Allen method. Atorvastatin (5 mg/kg) was intraperitoneally injected at 1 and 2 days after spinal cord injury. At 7 days post-injury, western blot assay, reverse transcription-polymerase chain reaction, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining results showed increased Beclin-1 and light chain 3B gene and protein expressions in the spinal cord injury + atorvastatin group. Additionally, caspase-9 and caspase-3 expression was decreased, and the number of TUNEL-positive cells was reduced. Compared with the spinal cord injury + saline group, Basso, Beattie, and Bresnahan locomotor rating scale scores significantly increased in the spinal cord injury + atorvastatin group at 14–42 days post-injury. These findings suggest that atorvastatin activated autophagy after spinal cord injury, inhibited apoptosis, and promoted recovery of neurological function.

  4. Nrf2 reduces levels of phosphorylated tau protein by inducing autophagy adaptor protein NDP52

    Science.gov (United States)

    Jo, Chulman; Gundemir, Soner; Pritchard, Susanne; Jin, Youngnam N.; Rahman, Irfan; Johnson, Gail V. W.

    2014-03-01

    Nuclear factor erythroid 2-related factor 2 (Nrf2) is a pivotal transcription factor in the defence against oxidative stress. Here we provide evidence that activation of the Nrf2 pathway reduces the levels of phosphorylated tau by induction of an autophagy adaptor protein NDP52 (also known as CALCOCO2) in neurons. The expression of NDP52, which we show has three antioxidant response elements (AREs) in its promoter region, is strongly induced by Nrf2, and its overexpression facilitates clearance of phosphorylated tau in the presence of an autophagy stimulator. In Nrf2-knockout mice, phosphorylated and sarkosyl-insoluble tau accumulates in the brains concurrent with decreased levels of NDP52. Moreover, NDP52 associates with phosphorylated tau from brain cortical samples of Alzheimer disease cases, and the amount of phosphorylated tau in sarkosyl-insoluble fractions is inversely proportional to that of NDP52. These results suggest that NDP52 plays a key role in autophagy-mediated degradation of phosphorylated tau in vivo.

  5. Autophagy as an ultrastructural marker of heavy metal toxicity in human cord blood hematopoietic stem cells

    International Nuclear Information System (INIS)

    Stem cells are a key target of environmental toxicants, but little is known about their toxicological responses. We aimed at developing an in-vitro model based on adult human stem cells to identify biomarkers of heavy metal exposure. To this end we investigated the responses of human CD34+ hematopoietic progenitor cells to hexavalent chromium (Cr[VI]) and cadmium (Cd). Parallel cultures of CD34+ cells isolated from umbilical cord blood were exposed for 48 h to 0.1 μM and 10 μM Cr(VI) or Cd. Cultures treated with 10 μM Cr(VI) or Cd showed marked cell loss. Ultrastructural analysis of surviving cells revealed prominent autophagosomes/autophagolysosomes, which is diagnostic of autophagy, associated with mitochondrial damage and replication, dilatation of the rough endoplasmic reticulum and Golgi complex, cytoplasmic lipid droplets and chromatin condensation. Treated cells did not show the morphologic hallmarks of apoptosis. Treatment with 0.1 μM Cr(VI) or Cd did not result in cell loss, but at the ultrastructural level cells showed dilated endoplasmic reticulum and evidence of mitochondrial damage. We conclude that autophagy is implicated in the response of human hematopoietic stem cells to toxic concentrations of Cr(VI) and Cd. Autophagy, which mediates cell survival and death under stress, deserves further evaluation to be established as biomarker of metal exposure

  6. Curcumin Suppresses Proliferation and Migration of MDA-MB-231 Breast Cancer Cells through Autophagy-Dependent Akt Degradation

    OpenAIRE

    Feng Guan; Youming Ding; Yemin Zhang; Yu Zhou; Mingxin Li; Changhua Wang

    2016-01-01

    Previous studies have evidenced that the anticancer potential of curcumin (diferuloylmethane), a main yellow bioactive compound from plant turmeric was mediated by interfering with PI3K/Akt signaling. However, the underlying molecular mechanism is still poorly understood. This study experimentally revealed that curcumin treatment reduced Akt protein expression in a dose- and time-dependent manner in MDA-MB-231 breast cancer cells, along with an activation of autophagy and suppression of ubiqu...

  7. Clinical pharmacology and malaria.

    Science.gov (United States)

    Breckenridge, A M; Winstanley, P A

    1997-10-01

    The role of clinical pharmacology in improving the prevention and treatment of malaria is reviewed. A series of general and specific issues is discussed, concentrating on risk-benefit and cost-effectiveness. The techniques of clinical pharmacokinetics play an important role in the optimal use of drugs and this is illustrated by studies on quinine and proguanil. In discussing amodiaquine toxicity, the role of the pharmacologist and the chemist in designing out drug toxicity lends hope for producing a new generation of antimalarial drugs. PMID:9625927

  8. Pharmacologic treatment of paraphilias.

    Science.gov (United States)

    Assumpção, Alessandra Almeida; Garcia, Frederico Duarte; Garcia, Heloise Delavenne; Bradford, John M W; Thibaut, Florence

    2014-06-01

    The treatment of paraphilias remains a challenge in the mental health field. Combined pharmacologic and psychotherapeutic treatment is associated with better efficacy. The gold standard treatment of severe paraphilias in adult males is antiandrogen treatment with cognitive behavioral therapy. Selective serotonin reuptake inhibitors have been used in mild types of paraphilia and in cases of sexual compulsions and juvenile paraphilias. Antiandrogen treatments seem to be effective in severe paraphilic subjects committing sexual offenses. In particular, gonadotropin-releasing hormone analogs have shown high efficacy working in a similar way to physical castration but being reversible at any time. Treatment recommendations, side effects, and contraindications are discussed. PMID:24877704

  9. The p-eIF2α/ATF4 pathway links endoplasmic reticulum stress to autophagy following the production of reactive oxygen species in mouse spermatocyte-derived cells exposed to dibutyl phthalate.

    Science.gov (United States)

    Zhang, Guowei; Ling, Xi; Liu, Kaijun; Wang, Zhi; Zou, Peng; Gao, Jianfang; Cao, Jia; Ao, Lin

    2016-07-01

    Dibutyl phthalate (DBP) is a widely used plasticizer that has been shown to induce germ cell apoptosis-related testicular atrophy and cause reproductive toxicity. Our previous results indicated that endoplasmic reticulum (ER) stress-activated autophagy served as a self-defense mechanism against DBP-induced germ cell apoptosis. However, the specific pathways that link ER stress and autophagy remain unclear. Here, we showed that exposure to DBP enhanced autophagic flux in mouse spermatocyte-derived GC-2 cells and that the eukaryotic translation initiation factor 2/activating transcription factor 4 pathway mediated ER stress-related autophagy independent of the mTOR and Beclin-1 pathways. Moreover, we demonstrated that DBP treatment led to the generation of reactive oxygen species (ROS) and that the inhibition of ROS by melatonin abrogated both ER stress and autophagy. The results indicated that excessive ROS production might be involved in DBP-induced ER stress and autophagy in GC-2 cells. Thus, ROS may serve as upstream mediators of ER stress and autophagy in DBP-treated GC-2 cells. PMID:27002192

  10. Moderate Hypothermia Significantly Decreases Hippocampal Cell Death Involving Autophagy Pathway after Moderate Traumatic Brain Injury.

    Science.gov (United States)

    Jin, Yichao; Lin, Yingying; Feng, Jun-feng; Jia, Feng; Gao, Guo-yi; Jiang, Ji-yao

    2015-07-15

    Here, we evaluated changes in autophagy after post-traumatic brain injury (TBI) followed by moderate hypothermia in rats. Adult male Sprague-Dawley rats were randomly divided into four groups: sham injury with normothermia group (37 °C); sham injury with hypothermia group (32 °C); TBI with normothermia group (TNG; 37 °C); and TBI with hypothermia group (THG; 32 °C). Injury was induced by a fluid percussion TBI device. Moderate hypothermia (32 °C) was achieved by partial immersion in a water bath (0 °C) under general anesthesia for 4 h. All rats were killed at 24 h after fluid percussion TBI. The ipsilateral hippocampus in all rats was analyzed with hematoxylin and eosin staining; terminal deoxynucleoitidyl transferase-mediated nick end labeling staining was used to determine cell death in ipsilateral hippocampus. Immunohistochemistry and western blotting of microtubule-associated protein light chain 3 (LC3), Beclin-1, as well as transmission electron microscopy performed to assess changes in autophagy. At 24 h after TBI, the cell death index was 27.90 ± 2.36% in TNG and 14.90 ± 1.52% in THG. Expression level of LC3 and Beclin-1 were significantly increased after TBI and were further up-regulated after post-TBI hypothermia. Further, ultrastructural observations showed that there was a marked increase of autophagosomes and autolysosomes in ipsilateral hippocampus after post-TBI hypothermia. Our data demonstrated that moderate hypothermia significantly attenuated cell death and increased autophagy in ipsilateral hippocampus after fluid percussion TBI. In conclusion, autophagy pathway may participate in the neuroprotective effect of post-TBI hypothermia. PMID:25942484

  11. Ethyl Pyruvate Ameliorates Hepatic Ischemia-Reperfusion Injury by Inhibiting Intrinsic Pathway of Apoptosis and Autophagy

    Directory of Open Access Journals (Sweden)

    Miao Shen

    2013-01-01

    Full Text Available Background. Hepatic ischemia-reperfusion (I/R injury is a pivotal clinical problem occurring in many clinical conditions such as transplantation, trauma, and hepatic failure after hemorrhagic shock. Apoptosis and autophagy have been shown to contribute to cell death in hepatic I/R injury. Ethyl pyruvate, a stable and simple lipophilic ester, has been shown to have anti-inflammatory properties. In this study, the purpose is to explore both the effect of ethyl pyruvate on hepatic I/R injury and regulation of intrinsic pathway of apoptosis and autophagy. Methods. Three doses of ethyl pyruvate (20 mg/kg, 40 mg/kg, and 80 mg/kg were administered 1 h before a model of segmental (70% hepatic warm ischemia was established in Balb/c mice. All serum and liver tissues were obtained at three different time points (4 h, 8 h, and 16 h. Results. Alanine aminotransferase (ALT, aspartate aminotransferase (AST, and pathological features were significantly ameliorated by ethyl pyruvate (80 mg/kg. The expression of Bcl-2, Bax, Beclin-1, and LC3, which play an important role in the regulation of intrinsic pathway of apoptosis and autophagy, was also obviously decreased by ethyl pyruvate (80 mg/kg. Furthermore, ethyl pyruvate inhibited the HMGB1/TLR4/ NF-κb axis and the release of cytokines (TNF-α and IL-6. Conclusion. Our results showed that ethyl pyruvate might attenuate to hepatic I/R injury by inhibiting intrinsic pathway of apoptosis and autophagy, mediated partly through downregulation of HMGB1/TLR4/ NF-κb axis and the competitive interaction with Beclin-1 of HMGB1.

  12. Streptococcus pneumoniae induces pyroptosis through the regulation of autophagy in murine microglia.

    Science.gov (United States)

    Kim, Ji-Yun; Paton, James C; Briles, David E; Rhee, Dong-Kwon; Pyo, Suhkneung

    2015-12-29

    Streptococcus pneumoniae is responsible for significant mortality and morbidity worldwide and causes invasive pneumococcal diseases including pneumococcal meningitis. Pyroptosis is caspase-1-dependent inflammatory cell death and is known to be induced by various microbial infections. In the present study, we investigated the molecular mechanisms that regulate pyroptosis induced by S. pneumoniae in microglia. Our results revealed that S. pneumoniae induced pyroptosis through caspase-1 activation and IL-1β production. We also found that the activation of caspase-1 and the maturation of IL-1β and IL-18 in the S. pneumoniae-triggered pyroptotic cell death process were mediated by NLRP3 inflammasome. In addition, pneumococcal infection increased the expression of autophagy-related genes and induced autophagosome formation. We also showed that the inhibition of autophagy promoted pneumococcus-induced pyroptosis. Furthermore, ROS was generated by pneumococcal infection and inhibited caspase-1 activation within 4 h of infection. However, in the late phase of infection, IL-1β secretion and caspase-1-dependent cell death were induced by ROS. These results suggest that autophagy induction transiently delay pyroptosis induced by S. pneumoniae in microglia. Our study also revealed that the activation of caspase-1 and the production of IL-1β were induced by pneumolysin and that pneumolysin triggered pyroptosis in microglial cells. Similar to the in vitro results, S. pneumoniae induced caspase-1 activation and caspase-1-dependent cytokine maturation in the mouse meningitis model. Thus, the present data demonstrate that S. pneumoniae induces pyroptosis in murine microglia and that NLRP3 inflammasome is critical for caspase-1 activation during the process. Furthermore, the induction of autophagy could transiently protect microglia from pyroptosis. PMID:26683708

  13. Ischemia preconditioning is neuroprotective in a rat cerebral ischemic injury model through autophagy activation and apoptosis inhibition

    Directory of Open Access Journals (Sweden)

    D.Y. Xia

    2013-08-01

    Full Text Available Sublethal ischemic preconditioning (IPC is a powerful inducer of ischemic brain tolerance. However, its underlying mechanisms are still not well understood. In this study, we chose four different IPC paradigms, namely 5 min (5 min duration, 5×5 min (5 min duration, 2 episodes, 15-min interval, 5×5×5 min (5 min duration, 3 episodes, 15-min intervals, and 15 min (15 min duration, and demonstrated that three episodes of 5 min IPC activated autophagy to the greatest extent 24 h after IPC, as evidenced by Beclin expression and LC3-I/II conversion. Autophagic activation was mediated by the tuberous sclerosis type 1 (TSC1-mTor signal pathway as IPC increased TSC1 but decreased mTor phosphorylation. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL and hematoxylin and eosin staining confirmed that IPC protected against cerebral ischemic/reperfusion (I/R injury. Critically, 3-methyladenine, an inhibitor of autophagy, abolished the neuroprotection of IPC and, by contrast, rapamycin, an autophagy inducer, potentiated it. Cleaved caspase-3 expression, neurological scores, and infarct volume in different groups further confirmed the protection of IPC against I/R injury. Taken together, our data indicate that autophagy activation might underlie the protection of IPC against ischemic injury by inhibiting apoptosis.

  14. Ischemia preconditioning is neuroprotective in a rat cerebral ischemic injury model through autophagy activation and apoptosis inhibition

    Energy Technology Data Exchange (ETDEWEB)

    Xia, D.Y. [Department of Neurology, Navy General Hospital of PLA, Beijing (China); Li, W. [General Hospital of Shenyang Military Command, Department of Neurology, Shenyang, China, Department of Neurology, General Hospital of Shenyang Military Command, Shenyang (China); Qian, H.R.; Yao, S.; Liu, J.G.; Qi, X.K. [Department of Neurology, Navy General Hospital of PLA, Beijing (China)

    2013-08-10

    Sublethal ischemic preconditioning (IPC) is a powerful inducer of ischemic brain tolerance. However, its underlying mechanisms are still not well understood. In this study, we chose four different IPC paradigms, namely 5 min (5 min duration), 5×5 min (5 min duration, 2 episodes, 15-min interval), 5×5×5 min (5 min duration, 3 episodes, 15-min intervals), and 15 min (15 min duration), and demonstrated that three episodes of 5 min IPC activated autophagy to the greatest extent 24 h after IPC, as evidenced by Beclin expression and LC3-I/II conversion. Autophagic activation was mediated by the tuberous sclerosis type 1 (TSC1)-mTor signal pathway as IPC increased TSC1 but decreased mTor phosphorylation. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and hematoxylin and eosin staining confirmed that IPC protected against cerebral ischemic/reperfusion (I/R) injury. Critically, 3-methyladenine, an inhibitor of autophagy, abolished the neuroprotection of IPC and, by contrast, rapamycin, an autophagy inducer, potentiated it. Cleaved caspase-3 expression, neurological scores, and infarct volume in different groups further confirmed the protection of IPC against I/R injury. Taken together, our data indicate that autophagy activation might underlie the protection of IPC against ischemic injury by inhibiting apoptosis.

  15. Ischemia preconditioning is neuroprotective in a rat cerebral ischemic injury model through autophagy activation and apoptosis inhibition

    International Nuclear Information System (INIS)

    Sublethal ischemic preconditioning (IPC) is a powerful inducer of ischemic brain tolerance. However, its underlying mechanisms are still not well understood. In this study, we chose four different IPC paradigms, namely 5 min (5 min duration), 5×5 min (5 min duration, 2 episodes, 15-min interval), 5×5×5 min (5 min duration, 3 episodes, 15-min intervals), and 15 min (15 min duration), and demonstrated that three episodes of 5 min IPC activated autophagy to the greatest extent 24 h after IPC, as evidenced by Beclin expression and LC3-I/II conversion. Autophagic activation was mediated by the tuberous sclerosis type 1 (TSC1)-mTor signal pathway as IPC increased TSC1 but decreased mTor phosphorylation. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and hematoxylin and eosin staining confirmed that IPC protected against cerebral ischemic/reperfusion (I/R) injury. Critically, 3-methyladenine, an inhibitor of autophagy, abolished the neuroprotection of IPC and, by contrast, rapamycin, an autophagy inducer, potentiated it. Cleaved caspase-3 expression, neurological scores, and infarct volume in different groups further confirmed the protection of IPC against I/R injury. Taken together, our data indicate that autophagy activation might underlie the protection of IPC against ischemic injury by inhibiting apoptosis

  16. Autophagy sensitivity of neuroendocrine lung tumor cells

    OpenAIRE

    HONG, SEUNG-KEUN; Kim, Jin-Hwan; Starenki, Dmytro; Park, Jong-In

    2013-01-01

    Neuroendocrine (NE) phenotypes characterize a spectrum of lung tumors, including low-grade typical and intermediate-grade atypical carcinoid, high-grade large-cell NE carcinoma and small cell lung carcinoma. Currently, no effective treatments are available to cure NE lung tumors, demanding identification of biological features specific to these tumors. Here, we report that autophagy has an important role for NE lung tumor cell proliferation and survival. We found that the expression levels of...

  17. Cardiomyocyte autophagy: metabolic profit and loss

    OpenAIRE

    Wang, Zhao V.; Ferdous, Anwarul; Hill, Joseph A.

    2013-01-01

    Cardiovascular disease remains the leading cause of morbidity and mortality worldwide, even despite recent scientific and technological advances and comprehensive preventive strategies. The cardiac myocyte is a voracious consumer of energy, and alterations in metabolic substrate availability and consumption are hallmark features of these disorders. Autophagy, an evolutionarily ancient response to metabolic insufficiency, has been implicated in the pathogenesis of a wide range of heart patholo...

  18. Autophagy in Mycobacterium tuberculosis and HIV infections

    OpenAIRE

    Espert, Lucile; Beaumelle, Bruno; Vergne, Isabelle

    2015-01-01

    Human Immunodeficiency Virus (HIV) and Mycobacterium tuberculosis (M.tb) are among the most lethal human pathogens worldwide, each being responsible for around 1.5 million deaths annually. Moreover, synergy between acquired immune deficiency syndrome (AIDS) and tuberculosis (TB) has turned HIV/M.tb co-infection into a major public health threat in developing countries. In the past decade, autophagy, a lysosomal catabolic process, has emerged as a major host immune defense mechanism against in...

  19. The Role of Autophagy in Lupus Nephritis

    OpenAIRE

    Linlin Wang; Helen Ka Wai Law

    2015-01-01

    Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease characterized by the generation of immune responses to self-antigens. Lupus nephritis is one of the most common and severe complications in SLE patients. Though the pathogenesis of lupus nephritis has been studied extensively, unresolved questions are still left and new therapeutic methods are needed for disease control. Autophagy is a conserved catabolic process through which cytoplasmic constituents can be degraded in...

  20. Autophagy and ethanol-induced liver injury

    Institute of Scientific and Technical Information of China (English)

    Terrence M Donohue Jr

    2009-01-01

    The majority of ethanol metabolism occurs in the liver. Consequently, this organ sustains the greatest damage from ethanol abuse. Ethanol consumption disturbs the delicate balance of protein homeostasis in the liver, causing intracellular protein accumulation due to a disruption of hepatic protein catabolism.Evidence indicates that ethanol or its metabolism impairs trafficking events in the liver, including the process of macroautophagy, which is the engulfment and degradation of cytoplasmic constituents by the lysosomal system. Autophagy is an essential, ongoing cellular process that is highly regulated by nutrients,endocrine factors and signaling pathways. A great number of the genes and gene products that govern the autophagic response have been characterized and the major metabolic and signaling pathways that activate or suppress autophagy have been identified. This review describes the process of autophagy, its regulation and the possible mechanisms by which ethanol disrupts the process of autophagic degradation. The implications of autophagic suppression are discussed in relation to the pathogenesis of alcohol-induced liver injury.

  1. FRS2α is Essential for the Fibroblast Growth Factor to Regulate the mTOR Pathway and Autophagy in Mouse Embryonic Fibroblasts

    Directory of Open Access Journals (Sweden)

    Xiang Lin, Yongyou Zhang, Leyuan Liu, Wallace L. McKeehan, Yuemao Shen, Siyang Song, Fen Wang

    2011-01-01

    Full Text Available Although the fibroblast growth factor (FGF signaling axis plays important roles in cell survival, proliferation, and differentiation, the molecular mechanism underlying how the FGF elicits these diverse regulatory signals is not well understood. By using the Frs2α null mouse embryonic fibroblast (MEF in conjunction with inhibitors to multiple signaling pathways, here we report that the FGF signaling axis activates mTOR via the FGF receptor substrate 2α (FRS2α-mediated PI3K/Akt pathway, and suppresses autophagy activity in MEFs. In addition, the PI3K/Akt pathway regulated mTOR is crucial for the FGF signaling axis to suppress autophagy in MEFs. Since autophagy has been proposed to play important roles in cell survival, proliferation, and differentiation, the findings suggest a novel mechanism for the FGF signaling axis to transmit regulatory signals to downstream effectors.

  2. Altered autophagy in human adipose tissues in obesity

    Science.gov (United States)

    Context: Autophagy is a housekeeping mechanism, involved in metabolic regulation and stress response, shown recently to regulate lipid droplets biogenesis/breakdown and adipose tissue phenotype. Objective: We hypothesized that in human obesity autophagy may be altered in adipose tissue in a fat d...

  3. Autophagy: A Potential Link between Obesity and Insulin Resistance

    NARCIS (Netherlands)

    P. Codogno; A.J. Meijer

    2010-01-01

    Dysregulation of autophagy contributes to aging and to diseases such as neurodegeneration, cardiomyopathy, and cancer. The paper by Yang et al. (2010) in this issue of Cell Metabolism indicates that defective autophagy may also underlie impaired insulin sensitivity in obesity and that upregulating a

  4. Biochemical Analysis of Autophagy in Algae and Plants by Monitoring the Electrophoretic Mobility of ATG8.

    Science.gov (United States)

    Pérez-Pérez, María Esther; Andrés-Garrido, Ascensión; Crespo, José L

    2016-01-01

    Identification of specific autophagy markers has been fundamental to investigate autophagy as catabolic process. Among them, the ATG8 protein turned out to be one of the most widely used and specific molecular markers of autophagy both in higher and lower eukaryotes. Here, we describe how ATG8 can be used to monitor autophagy in Chlamydomonas and Arabidopsis by western blot analysis. PMID:27424752

  5. Autophagy: Friend or Foe in Breast Cancer Development, Progression, and Treatment

    Directory of Open Access Journals (Sweden)

    Damian E. Berardi

    2011-01-01

    Although autophagy inhibition, combined with anticancer agents, could be therapeutically beneficial in some cases, autophagy induction by itself could lead to cell death in some apoptosis-resistant cancers, indicating that autophagy induction may also be used as a therapy. This paper summarizes the most important findings described in the literature about autophagy and also discusses the importance of this process in clinical settings.

  6. Pharmacology of antihypertensive drugs.

    Science.gov (United States)

    Pepper, G A

    1999-01-01

    The wide variety of first-line agents available for managing high blood pressure include diuretics, beta adrenergic receptor blockers, alpha adrenergic receptor blockers, angiotensin converting enzyme inhibitors, and calcium channel blockers. Supplemental agents used for second-line therapy and special indications, such as pregnancy and hypertensive emergencies, include angiotensin receptor blockers, central-acting agents, direct vasodilators, and adrenergic neuron inhibitors. Selection of agents for particular patients requires consideration of research-based evidence for positive long-term outcomes and of the unique patient profile of age, race, co-morbidities, and lifestyle. A thorough understanding of the pharmacology (mechanism, pharmacokinetics, adverse effects and drug interactions, clinical use) of antihypertensive agents is an essential foundation for nursing practice in women's health. PMID:10584919

  7. Pharmacology of Quercus infectoria.

    Science.gov (United States)

    Dar, M S; Ikram, M; Fakouhi, T

    1976-12-01

    The galls of Quercus infectoria (Fagaceae), a commonly available plant in Iran, were studied pharmacologically. Two fractions were employed, a dried acetone-treated methanol extract dissolved in water (Fraction A) and a subfraction prepared by chloroform-methanol extraction (Fraction B). Fraction A was active as an analgesic in rats and significantly reduced blood sugar levels in rabbits. Fraction B had CNS depressant activity. Data obtained with a treadmill indicated a decreased activity ratio by Fraction B, suggesting a possible interference in motor coordination. It potentiated the barbiturate sleeping time significantly without changing the onset time or the loss of the righting reflex. In addition, Fraction B exhibited a moderate antitremorine activity by causing a delay in the onset and a decrease in the severity of tremorine-induced tremors. The local anesthetic action of Fraction B was evident due to the complete blockade of the isolated frog sciatic nerve conduction. PMID:1032663

  8. Conus venom peptide pharmacology.

    Science.gov (United States)

    Lewis, Richard J; Dutertre, Sébastien; Vetter, Irina; Christie, MacDonald J

    2012-04-01

    Conopeptides are a diverse group of recently evolved venom peptides used for prey capture and/or defense. Each species of cone snails produces in excess of 1000 conopeptides, with those pharmacologically characterized (≈ 0.1%) targeting a diverse range of membrane proteins typically with high potency and specificity. The majority of conopeptides inhibit voltage- or ligand-gated ion channels, providing valuable research tools for the dissection of the role played by specific ion channels in excitable cells. It is noteworthy that many of these targets are found to be expressed in pain pathways, with several conopeptides having entered the clinic as potential treatments for pain [e.g., pyroglutamate1-MrIA (Xen2174)] and one now marketed for intrathecal treatment of severe pain [ziconotide (Prialt)]. This review discusses the diversity, pharmacology, structure-activity relationships, and therapeutic potential of cone snail venom peptide families acting at voltage-gated ion channels (ω-, μ-, μO-, δ-, ι-, and κ-conotoxins), ligand-gated ion channels (α-conotoxins, σ-conotoxin, ikot-ikot, and conantokins), G-protein-coupled receptors (ρ-conopeptides, conopressins, and contulakins), and neurotransmitter transporters (χ-conopeptides), with expanded discussion on the clinical potential of sodium and calcium channel inhibitors and α-conotoxins. Expanding the discovery of new bioactives using proteomic/transcriptomic approaches combined with high-throughput platforms and better defining conopeptide structure-activity relationships using relevant membrane protein crystal structures are expected to grow the already significant impact conopeptides have had as both research probes and leads to new therapies. PMID:22407615

  9. Opening new doors in autophagy research: Patrice Codogno.

    Science.gov (United States)

    Codogno, Patrice; Klionsky, Daniel J

    2016-06-01

    Patrice Codogno ( Fig. 1 ), one of the associate editors of Autophagy since it was established, is well known in the autophagy field, and has played a particularly important role in France, serving as the first president of Club Francophone de l'AuTophaGie (CFATG). Patrice's research career spans from the predominantly biochemical analyses that were commonly used in the 1980s to the molecular studies that are the primary focus of many labs currently studying autophagy today. Anyone who has met Patrice knows that he is modest, which means his contributions to autophagy and to promoting the careers of scientists globally, are underappreciated. In addition, there is a fun-loving side to Patrice that is often hidden to the casual observer, and it is time to share some of his personality and thoughts with the rest of the autophagy community. PMID:27158743

  10. Role of autophagy in the regulation of epithelial cell junctions.

    Science.gov (United States)

    Nighot, Prashant; Ma, Thomas

    2016-01-01

    Autophagy is a cell survival mechanism by which bulk cytoplasmic material, including soluble macromolecules and organelles, is targeted for lysosomal degradation. The role of autophagy in diverse cellular processes such as metabolic stress, neurodegeneration, cancer, aging, immunity, and inflammatory diseases is being increasingly recognized. Epithelial cell junctions play an integral role in the cell homeostasis via physical binding, regulating paracellular pathways, integrating extracellular cues into intracellular signaling, and cell-cell communication. Recent data indicates that cell junction composition is very dynamic. The junctional protein complexes are actively regulated in response to various intra- and extra-cellular clues by intracellular trafficking and degradation pathways. This review discusses the recent and emerging information on how autophagy regulates various epithelial cell junctions. The knowledge of autophagy regulation of epithelial junctions will provide further rationale for targeting autophagy in a wide variety of human disease conditions. PMID:27583189

  11. Autophagy in Plants--What's New on the Menu?

    Science.gov (United States)

    Michaeli, Simon; Galili, Gad; Genschik, Pascal; Fernie, Alisdair R; Avin-Wittenberg, Tamar

    2016-02-01

    Autophagy is a major cellular degradation pathway in eukaryotes. Recent studies have revealed the importance of autophagy in many aspects of plant life, including seedling establishment, plant development, stress resistance, metabolism, and reproduction. This is manifested by the dual ability of autophagy to execute bulk degradation under severe environmental conditions, while simultaneously to be highly selective in targeting specific compartments and protein complexes to regulate key cellular processes, even during favorable growth conditions. Delivery of cellular components to the vacuole enables their recycling, affecting the plant metabolome, especially under stress. Recent research in Arabidopsis has further unveiled fundamental mechanistic aspects in autophagy which may have relevance in non-plant systems. We review the most recent discoveries concerning autophagy in plants, touching upon all these aspects. PMID:26598298

  12. Modulation of Autophagy-Like Processes by Tumor Viruses

    Directory of Open Access Journals (Sweden)

    Karl Munger

    2012-06-01

    Full Text Available Autophagy is an intracellular degradation pathway for long-lived proteins and organelles. This process is activated above basal levels upon cell intrinsic or environmental stress and dysregulation of autophagy has been linked to various human diseases, including those caused by viral infection. Many viruses have evolved strategies to directly interfere with autophagy, presumably to facilitate their replication or to escape immune detection. However, in some cases, modulation of autophagy appears to be a consequence of the virus disturbing the cell’s metabolic signaling networks. Here, we summarize recent advances in research at the interface of autophagy and viral infection, paying special attention to strategies that human tumor viruses have evolved.

  13. PHARMACOLOGICAL IMPORTANCE OF CITRUS FRUITS

    Directory of Open Access Journals (Sweden)

    Amita Tomar *, Mridula Mall and Pragya Rai

    2013-01-01

    Full Text Available This paper reviews the pharmacological importance of citrus fruits. Citrus fruits are used for various pharmacological importance. According to literature the citrus fruit possess anti-cancer, antimicrobial, antioxidant, antiulcer, anti-inflammatory, and hypolipidemic and hepatoprotective properties.

  14. Pharmacological approach to acute pancreatitis

    DEFF Research Database (Denmark)

    Bang, Ulrich-Christian; Semb, Synne; Nojgaard, Camilla;

    2008-01-01

    The aim of the present review is to summarize the current knowledge regarding pharmacological prevention and treatment of acute pancreatitis (AP) based on experimental animal models and clinical trials. Somatostatin (SS) and octreotide inhibit the exocrine production of pancreatic enzymes and may....... Evidence based pharmacological treatment of AP is limited and studies on the effect of potent anti-inflammatory drugs are warranted....

  15. Activation of autophagy by unfolded proteins during endoplasmic reticulum stress.

    Science.gov (United States)

    Yang, Xiaochen; Srivastava, Renu; Howell, Stephen H; Bassham, Diane C

    2016-01-01

    Endoplasmic reticulum stress is defined as the accumulation of unfolded proteins in the endoplasmic reticulum, and is caused by conditions such as heat or agents that cause endoplasmic reticulum stress, including tunicamycin and dithiothreitol. Autophagy, a major pathway for degradation of macromolecules in the vacuole, is activated by these stress agents in a manner dependent on inositol-requiring enzyme 1b (IRE1b), and delivers endoplasmic reticulum fragments to the vacuole for degradation. In this study, we examined the mechanism for activation of autophagy during endoplasmic reticulum stress in Arabidopsis thaliana. The chemical chaperones sodium 4-phenylbutyrate and tauroursodeoxycholic acid were found to reduce tunicamycin- or dithiothreitol-induced autophagy, but not autophagy caused by unrelated stresses. Similarly, over-expression of BINDING IMMUNOGLOBULIN PROTEIN (BIP), encoding a heat shock protein 70 (HSP70) molecular chaperone, reduced autophagy. Autophagy activated by heat stress was also found to be partially dependent on IRE1b and to be inhibited by sodium 4-phenylbutyrate, suggesting that heat-induced autophagy is due to accumulation of unfolded proteins in the endoplasmic reticulum. Expression in Arabidopsis of the misfolded protein mimics zeolin or a mutated form of carboxypeptidase Y (CPY*) also induced autophagy in an IRE1b-dependent manner. Moreover, zeolin and CPY* partially co-localized with the autophagic body marker GFP-ATG8e, indicating delivery to the vacuole by autophagy. We conclude that accumulation of unfolded proteins in the endoplasmic reticulum is a trigger for autophagy under conditions that cause endoplasmic reticulum stress. PMID:26616142

  16. 维生素D和自噬与疾病的关系%Vitamin D,Autophagy and Diseases

    Institute of Scientific and Technical Information of China (English)

    甄超; 冯雪丹; 王高宁(综述); 郭力(审校)

    2015-01-01

    自噬是真核细胞的Ⅱ型程序性细胞死亡过程,自噬失调会导致多种疾病的发生。该领域已经成为目前生物医学研究的热点,而通过调控自噬活性来防治疾病是重要的研发方向。研究表明,维生素D除具有维持机体钙磷代谢、介导免疫反应等功能外,还能介导自噬活性,参与多系统疾病的发生。深入了解维生素D的自噬调节功能及其与疾病的关系不仅有助于阐明疾病病理机制,还具有重要的实际应用意义。%Autophagy is typeⅡ programmed cell death process of all eukaryotic cells.Autophagy disor-ders can lead to a variety of diseases,and it has become a hot field of biomedical research.To prevent and treat diseases by regulating autophagy activity has become an important research direction .Studies have shown that vitamin D is not only involved in calcium and phosphorus metabolism ,immune response, but also capable of mediating autophagy activity,and related to multi-system diseases.Depth understanding of the autophagy function of vitamin D and its relationship with the diseases not only will help elucidate the patho-genesis of these diseases,but also have important practical significance.

  17. Cordycepin-induced apoptosis and autophagy in breast cancer cells are independent of the estrogen receptor

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sunga [Department of Physiology, School of Medicine, Chungnam National University, Daejeon, 301747 (Korea, Republic of); Lim, Mi-Hee [Department of Biochemistry, Kangwon National University, Gangwon-do, 200701 (Korea, Republic of); Kim, Ki Mo [Diabetic Complications Research Center, Division of Traditional Korean Medicine (TKM) Integrated Research, Korea Institute of Oriental Medicine (KIOM), 305811, Daejeon (Korea, Republic of); Jeon, Byeong Hwa [Department of Physiology, School of Medicine, Chungnam National University, Daejeon, 301747 (Korea, Republic of); Song, Won O. [Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824 (United States); Kim, Tae Woong, E-mail: tawkim@kangwon.ac.kr [Department of Biochemistry, Kangwon National University, Gangwon-do, 200701 (Korea, Republic of)

    2011-12-15

    Cordycepin (3-deoxyadenosine), found in Cordyceps spp., has been known to have many therapeutic effects including immunomodulatory, anti-inflammatory, antimicrobial, and anti-aging effects. Moreover, anti-tumor and anti-metastatic effects of cordycepin have been reported, but the mechanism causing cancer cell death is poorly characterized. The present study was designed to investigate whether the mechanisms of cordycepin-induced cell death were associated with estrogen receptor in breast cancer cells. Exposure of both MDA-MB-231 and MCF-7 human breast cancer cells to cordycepin resulted in dose-responsive inhibition of cell growth and reduction in cell viability. The cordycepin-induced cell death in MDA-MB-231 cells was associated with several specific features of the mitochondria-mediated apoptotic pathway, which was confirmed by DNA fragmentation, TUNEL, and biochemical assays. Cordycepin also caused a dose-dependent increase in mitochondrial translocation of Bax, triggering cytosolic release of cytochrome c and activation of caspases-9 and -3. Interestingly, MCF-7 cells showed autophagy-associated cell death, as observed by the detection of an autophagosome-specific protein and large membranous vacuole ultrastructure morphology in the cytoplasm. Cordycepin-induced autophagic cell death has applications in treating MCF-7 cells with apoptotic defects, irrespective of the ER response. Although autophagy has a survival function in tumorigenesis of some cancer cells, autophagy may be important for cordycepin-induced MCF-7 cell death. In conclusion, the results of our study demonstrate that cordycepin effectively kills MDA-MB-231 and MCF-7 human breast cancer cell lines in culture. Hence, further studies should be conducted to determine whether cordycepin will be a clinically useful, ER-independent, chemotherapeutic agent for human breast cancer. -- Highlights: Black-Right-Pointing-Pointer We studied the mechanism which cordycepin-induced cell death association with

  18. Cordycepin-induced apoptosis and autophagy in breast cancer cells are independent of the estrogen receptor

    International Nuclear Information System (INIS)

    Cordycepin (3-deoxyadenosine), found in Cordyceps spp., has been known to have many therapeutic effects including immunomodulatory, anti-inflammatory, antimicrobial, and anti-aging effects. Moreover, anti-tumor and anti-metastatic effects of cordycepin have been reported, but the mechanism causing cancer cell death is poorly characterized. The present study was designed to investigate whether the mechanisms of cordycepin-induced cell death were associated with estrogen receptor in breast cancer cells. Exposure of both MDA-MB-231 and MCF-7 human breast cancer cells to cordycepin resulted in dose-responsive inhibition of cell growth and reduction in cell viability. The cordycepin-induced cell death in MDA-MB-231 cells was associated with several specific features of the mitochondria-mediated apoptotic pathway, which was confirmed by DNA fragmentation, TUNEL, and biochemical assays. Cordycepin also caused a dose-dependent increase in mitochondrial translocation of Bax, triggering cytosolic release of cytochrome c and activation of caspases-9 and -3. Interestingly, MCF-7 cells showed autophagy-associated cell death, as observed by the detection of an autophagosome-specific protein and large membranous vacuole ultrastructure morphology in the cytoplasm. Cordycepin-induced autophagic cell death has applications in treating MCF-7 cells with apoptotic defects, irrespective of the ER response. Although autophagy has a survival function in tumorigenesis of some cancer cells, autophagy may be important for cordycepin-induced MCF-7 cell death. In conclusion, the results of our study demonstrate that cordycepin effectively kills MDA-MB-231 and MCF-7 human breast cancer cell lines in culture. Hence, further studies should be conducted to determine whether cordycepin will be a clinically useful, ER-independent, chemotherapeutic agent for human breast cancer. -- Highlights: ► We studied the mechanism which cordycepin-induced cell death association with estrogen receptor (ER) in

  19. 7-Ketocholesterol Induces Autophagy in Vascular Smooth Muscle Cells through Nox4 and Atg4B

    OpenAIRE

    He, Chaoyong; Zhu, Huaiping; Zhang, Wencheng; Okon, Imoh; Wang, Qilong; Li, Hongliang; Le, Yun-Zheng; Xie, Zhonglin

    2013-01-01

    Oxidized lipoproteins stimulate autophagy in advanced atherosclerotic plaques. However, the mechanisms underlying autophagy induction and the role of autophagy in atherogenesis remain to be determined. This study was designed to investigate the mechanisms by which 7-ketocholesterol (7-KC), a major component of oxidized lipoproteins, induces autophagy. This study was also designed to determine the effect of autophagy induction on apoptosis, a central event in the development of atherosclerosis...

  20. Suppression of autophagy by extracellular vesicles promotes myofibroblast differentiation in COPD pathogenesis

    Directory of Open Access Journals (Sweden)

    Yu Fujita

    2015-11-01

    Full Text Available Extracellular vesicles (EVs, such as exosomes and microvesicles, encapsulate proteins and microRNAs (miRNAs as new modulators of both intercellular crosstalk and disease pathogenesis. The composition of EVs is modified by various triggers to maintain physiological homeostasis. In response to cigarette smoke exposure, the lungs develop emphysema, myofibroblast accumulation and airway remodelling, which contribute to chronic obstructive pulmonary disease (COPD. However, the lung disease pathogenesis through modified EVs in stress physiology is not understood. Here, we investigated an EV-mediated intercellular communication mechanism between primary human bronchial epithelial cells (HBECs and lung fibroblasts (LFs and discovered that cigarette smoke extract (CSE-induced HBEC-derived EVs promote myofibroblast differentiation in LFs. Thorough evaluations of the modified EVs and COPD lung samples showed that cigarette smoke induced relative upregulation of cellular and EV miR-210 expression of bronchial epithelial cells. Using co-culture assays, we showed that HBEC-derived EV miR-210 promotes myofibroblast differentiation in LFs. Surprisingly, we found that miR-210 directly regulates autophagy processes via targeting ATG7, and expression levels of miR-210 are inversely correlated with ATG7 expression in LFs. Importantly, autophagy induction was significantly decreased in LFs from COPD patients, and silencing ATG7 in LFs led to myofibroblast differentiation. These findings demonstrate that CSE triggers the modification of EV components and identify bronchial epithelial cell-derived miR-210 as a paracrine autophagy mediator of myofibroblast differentiation that has potential as a therapeutic target for COPD. Our findings show that stressor exposure changes EV compositions as emerging factors, potentially controlling pathological disorders such as airway remodelling in COPD.

  1. Key role of phosphodiesterase 4A (PDE4A) in autophagy triggered by yessotoxin

    International Nuclear Information System (INIS)

    Highlights: • YTX activates autophagic cell death after 48 h of treatment. • After 24 h of YTX incubation, the autophagic LC3B expression is increased. • High LC3B levels after 24 h can be related with extrinsic apoptosis activated by YTX. • PDEA4 plays a key role in the autophagy activation. - Abstract: Understanding the mechanism of action of the yessotoxin (YTX) is crucial since this drug has potential pharmacological effects in allergic processes, tumor proliferation and neurodegenerative diseases. It has been described that YTX activates apoptosis after 24 h of treatment, while after 48 h of incubation with the toxin a decrease in cell viability corresponding to cellular differentiation or non-apoptotic cell death was observed. In this paper, these processes were extensively studied by using the erythroleukemia K-562 cell line. On one hand, events of K-562 cell differentiation into erythrocytes after YTX treatment were studied using hemin as positive control of cell differentiation. Cell differentiation was studied through the cyclic nucleotide response element binding (phospho-CREB) and the transferrin receptor (TfR) expression. On the other hand, using rapamycin as positive control, autophagic hallmarks, as non-apoptotic cell death, were studied after toxin exposure. In this case, the mechanistic target of rapamycin (mTOR) and light chain 3B (LC3B) levels were measured to check autophagy activation. The results showed that cell differentiation was not occurring after 48 h of toxin incubation while at this time the autophagy was triggered. Furthermore after 24 h of toxin treatment none of these processes were activated. In addition, the role of the type 4A phosphodiesterase (PDE4A), the intracellular target of YTX, was checked. PDE4A-silencing experiments showed different regulation steps of PDE4A in the autophagic processes triggered either by traditional compounds or YTX. In summary, after 48 h YTX treatment PDE4A-dependent autophagy, as non

  2. Nucleocytoplasmic transport blockage by SV40 peptide-modified gold nanoparticles induces cellular autophagy

    Directory of Open Access Journals (Sweden)

    Tsai TL

    2012-10-01

    Full Text Available Tsung-Lin Tsai,1,5 Chia-Cheng Hou,1,5 Hao-Chen Wang,1,5 Zih-Syuan Yang,2 Chen-Sheng Yeh,4 Dar-Bin Shieh,2,3 Wu-Chou Su1,51Institute of Basic Medical Sciences, 2Institute of Oral Medicine and Department of Stomatology, 3Center for Micro/Nano Science and Technology, 4Department of Chemistry, National Cheng Kung University, Tainan, Taiwan; 5Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, TaiwanAbstract: Gold nanoparticles modified with the nuclear localization signal from simian virus 40 large T antigen (GNP-PEG/SV40 accumulate on the cytoplasmic side of the nuclear membrane in HeLa cells. Accumulation of GNP-PEG/SV40 around the nucleus blocks nucleocytoplasmic transport and prevents RNA export and nuclear shuttling of signaling proteins. This long-term blockage of nucleocytoplasmic transport results in cell death. This cell death is not caused by apoptosis or necrosis because caspases 3 and 9 are not activated, and the expression of annexin V/propidium iodide is not enhanced in HeLa cells after treatment. Using transmission electron microscopy, autophagosomes and autolysosomes were seen to appear after 72 hours of treatment with GNP-PEG/SV40. Increasing levels of enhanced green fluorescent protein-microtubule-associated protein 1 light chain 3 (EGFP-LC3-positive punctate and LC3-II confirmed GNP-PEG/SV40-induced autophagy. In SiHa cells, treatment did not induce accumulation of GNP-PEG/SV40 around the nucleus and autophagy. Treating cells with wheat germ agglutinin, a nuclear pore complex inhibitor, induced autophagy in both HeLa and SiHa cells. GNP-PEG/SV40-induced autophagy plays a role in cell death, not survival, and virus-mediated small hairpin RNA silencing of Beclin-1 attenuates cell death. Taken together, the results indicate that long-term blockade of nucleocytoplasmic transport results in autophagic cell death.Keywords: gold nanoparticles

  3. Concanavalin A: A potential anti-neoplastic agent targeting apoptosis, autophagy and anti-angiogenesis for cancer therapeutics

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wen-wen; Yu, Jia-ying; Xu, Huai-long [School of Life Sciences and State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610064 (China); Bao, Jin-ku, E-mail: jinkubao@yahoo.com [School of Life Sciences and State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610064 (China)

    2011-10-22

    Highlights: {yields} ConA induces cancer cell death targeting apoptosis and autophagy. {yields} ConA inhibits cancer cell angiogenesis. {yields} ConA is utilized in pre-clinical and clinical trials. -- Abstract: Concanavalin A (ConA), a Ca{sup 2+}/Mn{sup 2+}-dependent and mannose/glucose-binding legume lectin, has drawn a rising attention for its remarkable anti-proliferative and anti-tumor activities to a variety of cancer cells. ConA induces programmed cell death via mitochondria-mediated, P73-Foxo1a-Bim apoptosis and BNIP3-mediated mitochondrial autophagy. Through IKK-NF-{kappa}B-COX-2, SHP-2-MEK-1-ERK, and SHP-2-Ras-ERK anti-angiogenic pathways, ConA would inhibit cancer cell survival. In addition, ConA stimulates cell immunity and generates an immune memory, resisting to the same genotypic tumor. These biological findings shed light on new perspectives of ConA as a potential anti-neoplastic agent targeting apoptosis, autophagy and anti-angiogenesis in pre-clinical or clinical trials for cancer therapeutics.

  4. Concanavalin A: A potential anti-neoplastic agent targeting apoptosis, autophagy and anti-angiogenesis for cancer therapeutics

    International Nuclear Information System (INIS)

    Highlights: → ConA induces cancer cell death targeting apoptosis and autophagy. → ConA inhibits cancer cell angiogenesis. → ConA is utilized in pre-clinical and clinical trials. -- Abstract: Concanavalin A (ConA), a Ca2+/Mn2+-dependent and mannose/glucose-binding legume lectin, has drawn a rising attention for its remarkable anti-proliferative and anti-tumor activities to a variety of cancer cells. ConA induces programmed cell death via mitochondria-mediated, P73-Foxo1a-Bim apoptosis and BNIP3-mediated mitochondrial autophagy. Through IKK-NF-κB-COX-2, SHP-2-MEK-1-ERK, and SHP-2-Ras-ERK anti-angiogenic pathways, ConA would inhibit cancer cell survival. In addition, ConA stimulates cell immunity and generates an immune memory, resisting to the same genotypic tumor. These biological findings shed light on new perspectives of ConA as a potential anti-neoplastic agent targeting apoptosis, autophagy and anti-angiogenesis in pre-clinical or clinical trials for cancer therapeutics.

  5. [Pharmacological treatment of obesity].

    Science.gov (United States)

    Gomis Barbará, R

    2004-01-01

    The pharmacological treatment of obesity should be considered when cannot be achieved a 10% weight loss with diet therapy and physical activity. The drugs effective in obesity treatment may act by different mechanisms such as reduction in food intake, inhibition of fat absorption, increase of thermogenesis and stimulation of adipocyte apoptosis. At present, we only have two marketed drugs for obesity treatment. Sibutramine is an inhibitor of norepinephrine, dopamine and serotonina reuptake which inhibits food intake and increases thermogenesis. Sibutramine administration for a year can induce a weight loss of 4-7%. Its main side effects are hypertension, headache, insomnia and constipation. Orlistat is an inhibitor of pancreatic lipase which is able to block the absorption of 30% of ingested fat. Its administration induces weight loss and reduction of ulterior weight regain. Also, this drug improves hypertension dyslipdaemia and helps to prevent diabetes in 52% of cases when administered over four years. The increase in frequency of stools and interference with vitamin absorption are its main side effects. Glucagon-like peptide 1, which increases insulin sensitivity and satiety, adiponectin and PPAR-gamma agonists which reduce insulin resistance and modulates adipocyte generation are the basis for future therapeutic approaches of obesity. Phosphatase inhibitors induce PPAR-gamma phosphorylation and UCP-1 expression leading to an increase in thermogenesis and reduction in appetite. PMID:15382615

  6. Pharmacology of cannabinoids.

    Science.gov (United States)

    Grotenhermen, Franjo

    2004-01-01

    Dronabinol (Delta 9-tetrahydocannabinol, THC), the main source of the pharmacological effects caused by the use of cannabis, is an agonist to both the CB1 and the CB2 subtype of cannabinoid receptors. It is available on prescription in several countries. The non-psychotropic cannabidiol (CBD), some analogues of natural cannabinoids and their metabolites, antagonists at the cannabinoid receptors and modulators of the endogenous cannabinoid system are also promising candidates for clinical research and therapeutic uses. Cannabinoid receptors are distributed in the central nervous system and many peripheral tissues including spleen, leukocytes; reproductive, urinary and gastrointestinal tracts; endocrine glands, arteries and heart. Five endogenous cannabinoids have been detected so far, of whom anandamide and 2-arachidonylglycerol are best characterized. There is evidence that besides the two cannabinoid receptor subtypes cloned so far additional cannabinoid receptor subtypes and vanilloid receptors are involved in the complex physiological functions of the cannabinoid system that include motor coordination, memory procession, control of appetite, pain modulation and neuroprotection. Strategies to modulate their activity include inhibition of re-uptake into cells and inhibition of their degradation to increase concentration and duration of action. Properties of cannabinoids that might be of therapeutic use include analgesia, muscle relaxation, immunosuppression, anti-inflammation, anti-allergic effects, sedation, improvement of mood, stimulation of appetite, anti-emesis, lowering of intraocular pressure, bronchodilation, neuroprotection and antineoplastic effects. PMID:15159677

  7. Toll-like receptor 4 knockout alleviates paraquat-induced cardiomyocyte contractile dysfunction through an autophagy-dependent mechanism.

    Science.gov (United States)

    Wang, Shuyi; Zhu, Xiaoling; Xiong, Lize; Zhang, Yingmei; Ren, Jun

    2016-08-22

    Paraquat, a quarternary nitrogen herbicide, is a toxic prooxidant leading to multi-organ failure including the heart although the underlying mechanism remains poorly understood. This study was designed to examine the role of the innate proinflammatory mediator toll-like receptor 4 (TLR4) in paraquat-induced cardiac contractile anomalies and the underlying mechanisms involved with a focus on autophagy, a conservative machinery governing protein and organelle degradation and recycling for cardiac homeostasis. Wild-type (WT) and TLR4 knockout (TLR4(-/-)) mice were challenged with paraquat (45mg/kg, i.p.) for 48h. Paraquat challenge did not affect mRNA levels of TLR2, TLR4 and TLR9 in WT mice nor did paraquat treatment alter TREM-1 levels. Paraquat challenge elicited cardiac mechanical defects including compromised cardiomyocyte contractile function, intracellular Ca(2+) handling, and overt autophagy as manifested by increased LC3BII-to-LC3BI ratio, Atg5, Atg7 and p62 levels. Interestingly, TLR4 knockout significantly attenuated paraquat-induced cardiac contractile and intracellular Ca(2+) derangement as well as alterations of autophagy markers. Paraquat-elicited changes in cardiac autophagy markers (LC3BII, LC3BII-to-LC3BI ratio and p62) were augmented by lysosomal inhibition using bafilomycin A1 in WT mice. TLR4 knockout significantly attenuated or negated paraquat-elicited increase in LC3BII, LC3BII-to-LC3BI ratio and p62 levels in the presence of lysosomal inhibition. In addition, paraquat challenge promoted phosphorylation of AMPK while suppressing the phosphorylation of mTOR and ULK1 (the autophagy inhibitory Ser(757)), the effects of which were significantly attenuated by TLR4 ablation. In vitro study revealed that AMPK activation using AICAR or mTOR inhibition using rapamycin effectively negated the beneficial cardiomyocyte mechanical effects of TLR4 inhibition (CLI-095) against paraquat toxicity, supporting a permissive role for AMPK-mTOR in TLR4 inhibition

  8. Retromer Is Essential for Autophagy-Dependent Plant Infection by the Rice Blast Fungus.

    Science.gov (United States)

    Zheng, Wenhui; Zhou, Jie; He, Yunlong; Xie, Qiurong; Chen, Ahai; Zheng, Huawei; Shi, Lei; Zhao, Xu; Zhang, Chengkang; Huang, Qingping; Fang, Kunhai; Lu, Guodong; Ebbole, Daniel J; Li, Guangpu; Naqvi, Naweed I; Wang, Zonghua

    2015-12-01

    The retromer mediates protein trafficking through recycling cargo from endosomes to the trans-Golgi network in eukaryotes. However, the role of such trafficking events during pathogen-host interaction remains unclear. Here, we report that the cargo-recognition complex (MoVps35, MoVps26 and MoVps29) of the retromer is essential for appressorium-mediated host penetration by Magnaporthe oryzae, the causal pathogen of the blast disease in rice. Loss of retromer function blocked glycogen distribution and turnover of lipid bodies, delayed nuclear degeneration and reduced turgor during appressorial development. Cytological observation revealed dynamic MoVps35-GFP foci co-localized with autophagy-related protein RFP-MoAtg8 at the periphery of autolysosomes. Furthermore, RFP-MoAtg8 interacted with MoVps35-GFP in vivo, RFP-MoAtg8 was mislocalized to the vacuole and failed to recycle from the autolysosome in the absence of the retromer function, leading to impaired biogenesis of autophagosomes. We therefore conclude that retromer is essential for autophagy-dependent plant infection by the rice blast fungus. PMID:26658729

  9. The Regulation of Autophagy by Influenza A Virus

    Directory of Open Access Journals (Sweden)

    Rong Zhang

    2014-01-01

    Full Text Available Influenza A virus is a dreadful pathogen of animals and humans, causing widespread infection and severe morbidity and mortality. It is essential to characterize the influenza A virus-host interaction and develop efficient counter measures against the viral infection. Autophagy is known as a catabolic process for the recycling of the cytoplasmic macromolecules. Recently, it has been shown that autophagy is a critical mechanism underlying the interaction between influenza A virus and its host. Autophagy can be induced by the infection with influenza A virus, which is considered as a necessary process for the viral proliferation, including the accumulation of viral elements during the replication of influenza A virus. On the other hand, influenza A virus can inhibit the autophagic formation via interaction with the autophagy-related genes (Atg and signaling pathways. In addition, autophagy is involved in the influenza virus-regulated cell deaths, leading to significant changes in host apoptosis. Interestingly, the high pathogenic strains of influenza A virus, such as H5N1, stimulate autophagic cell death and appear to interplay with the autophagy in distinct ways as compared with low pathogenic strains. This review discusses the regulation of autophagy, an influenza A virus driven process.

  10. Targeting autophagy in cancer management – strategies and developments

    Directory of Open Access Journals (Sweden)

    Ozpolat B

    2015-09-01

    Full Text Available Bulent Ozpolat,1 Doris M Benbrook2 1Department of Experimental Therapeutics, The University of Texas – Houston, MD Anderson Cancer Center, Houston, TX, 2Department of Obstetrics and Gynecology, University of Oklahoma HSC, Oklahoma City, OK, USA Abstract: Autophagy is a highly regulated catabolic process involving lysosomal degradation of intracellular components, damaged organelles, misfolded proteins, and toxic aggregates, reducing oxidative stress and protecting cells from damage. The process is also induced in response to various conditions, including nutrient deprivation, metabolic stress, hypoxia, anticancer therapeutics, and radiation therapy to adapt cellular conditions for survival. Autophagy can function as a tumor suppressor mechanism in normal cells and dysregulation of this process (ie, monoallelic Beclin-1 deletion may lead to malignant transformation and carcinogenesis. In tumors, autophagy is thought to promote tumor growth and progression by helping cells to adapt and survive in metabolically-challenged and harsh tumor microenvironments (ie, hypoxia and acidity. Recent in vitro and in vivo studies in preclinical models suggested that modulation of autophagy can be used as a therapeutic modality to enhance the efficacy of conventional therapies, including chemo and radiation therapy. Currently, more than 30 clinical trials are investigating the effects of autophagy inhibition in combination with cytotoxic chemotherapies and targeted agents in various cancers. In this review, we will discuss the role, molecular mechanism, and regulation of autophagy, while targeting this process as a novel therapeutic modality, in various cancers. Keywords: autophagy inhibition, chemotherapy, tumor microenvironment

  11. Laser stimulation can activate autophagy in HeLa cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yisen; Hu, Minglie; Wang, Chingyue [Ultrafast Laser Laboratory, Key Laboratory of Optoelectronic Information Technology (Ministry of Education), College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin (China); Lan, Bei; Cao, Youjia [Key Laboratory of Microbial Functional Genomics of Ministry of Education, College of Life Sciences, Nankai University, Tianjin (China); He, Hao, E-mail: haohe@tju.edu.cn [Ultrafast Laser Laboratory, Key Laboratory of Optoelectronic Information Technology (Ministry of Education), College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin (China); Med-X Research Institute, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai (China)

    2014-10-27

    For decades, lasers have been a daily tool in most biological research for fluorescent excitation by confocal or multiphoton microscopy. More than 20 years ago, cell photodamage caused by intense laser stimulation was noticed by generating reactive oxygen species, which was then thought as the main damage effect by photons. In this study, we show that laser stimulation can induce autophagy, an important cell lysosomal pathway responding to immune stimulation and starvation, without any biochemical treatment. Two different types of laser stimulations are found to be capable of activating autophagy: continuous scanning by continuous-wave visible lasers and a short-time flash of femtosecond laser irradiation. The autophagy generation is independent from wavelength, power, and scanning duration of the visible lasers. In contrast, the power of femtosecond laser is very critical to autophagy because the multiphoton excited Ca{sup 2+} dominates autophagy signaling. In general, we show here the different mechanisms of autophagy generation by such laser stimulation, which correspond to confocal microscopy and cell surgery, respectively. Those results can help further understanding of photodamage and autophagy signaling.

  12. Laser stimulation can activate autophagy in HeLa cells

    Science.gov (United States)

    Wang, Yisen; Lan, Bei; He, Hao; Hu, Minglie; Cao, Youjia; Wang, Chingyue

    2014-10-01

    For decades, lasers have been a daily tool in most biological research for fluorescent excitation by confocal or multiphoton microscopy. More than 20 years ago, cell photodamage caused by intense laser stimulation was noticed by generating reactive oxygen species, which was then thought as the main damage effect by photons. In this study, we show that laser stimulation can induce autophagy, an important cell lysosomal pathway responding to immune stimulation and starvation, without any biochemical treatment. Two different types of laser stimulations are found to be capable of activating autophagy: continuous scanning by continuous-wave visible lasers and a short-time flash of femtosecond laser irradiation. The autophagy generation is independent from wavelength, power, and scanning duration of the visible lasers. In contrast, the power of femtosecond laser is very critical to autophagy because the multiphoton excited Ca2+ dominates autophagy signaling. In general, we show here the different mechanisms of autophagy generation by such laser stimulation, which correspond to confocal microscopy and cell surgery, respectively. Those results can help further understanding of photodamage and autophagy signaling.

  13. Regulation of autophagy in oxygen-dependent cellular stress.

    Science.gov (United States)

    Ryter, Stefan W; Choi, Augustine M K

    2013-01-01

    Oxidative stress caused by supraphysiological production of reactive oxygen species (ROS), can cause cellular injury associated with protein and lipid oxidation, DNA damage, and mitochondrial dysfunction. The cellular responses triggered by oxidative stress include the altered regulation of signaling pathways that culminate in the regulation of cell survival or cell death pathways. Recent studies suggest that autophagy, a cellular homeostatic process that governs the turnover of damaged organelles and proteins, may represent a general cellular and tissue response to oxidative stress. The autophagic pathway involves the encapsulation of substrates in double-membraned vesicles, which are subsequently delivered to the lysosome for enzymatic degradation and recycling of metabolic precursors. Autophagy may play multifunctional roles in cellular adaptation to stress, by maintaining mitochondrial integrity, and removing damaged proteins. Additionally, autophagy may play important roles in the regulation of inflammation and immune function. Modulation of the autophagic pathway has been reported in cell culture models of oxidative stress, including altered states of oxygen tension (i.e., hypoxia, hyperoxia), and exposure to oxidants. Furthermore, proteins that regulate autophagy may be subject to redox regulation. The heme oxygenase- 1 (HO)-1 enzyme system may have a role in the regulation of autophagy. Recent studies suggest that carbon monoxide (CO), a reaction product of HO activity which can alter mitochondrial function, may induce autophagy in cultured epithelial cells. In conclusion, current research suggests a central role for autophagy as a mammalian oxidative stress response and its interrelationship to other stress defense systems. PMID:23092322

  14. Laser stimulation can activate autophagy in HeLa cells

    International Nuclear Information System (INIS)

    For decades, lasers have been a daily tool in most biological research for fluorescent excitation by confocal or multiphoton microscopy. More than 20 years ago, cell photodamage caused by intense laser stimulation was noticed by generating reactive oxygen species, which was then thought as the main damage effect by photons. In this study, we show that laser stimulation can induce autophagy, an important cell lysosomal pathway responding to immune stimulation and starvation, without any biochemical treatment. Two different types of laser stimulations are found to be capable of activating autophagy: continuous scanning by continuous-wave visible lasers and a short-time flash of femtosecond laser irradiation. The autophagy generation is independent from wavelength, power, and scanning duration of the visible lasers. In contrast, the power of femtosecond laser is very critical to autophagy because the multiphoton excited Ca2+ dominates autophagy signaling. In general, we show here the different mechanisms of autophagy generation by such laser stimulation, which correspond to confocal microscopy and cell surgery, respectively. Those results can help further understanding of photodamage and autophagy signaling.

  15. Quality management of pharmacology and safety pharmacology studies

    DEFF Research Database (Denmark)

    Spindler, Per; Seiler, Jürg P

    2002-01-01

    Pharmacology has traditionally been excluded from the mandatory application of good laboratory practice (GLP) principles. Consensus has been reached through the process of the International Conference on Harmonisation (ICH, Topic S7A) with regard to the definitions of the different types of...... pharmacology studies (ICH S7A): primary pharmacodynamic, secondary pharmacodynamic and safety pharmacology studies, and guidance on the quality standards (expectations for GLP conformity) for these study types have been provided. Primary pharmacodynamic studies are the only study types that are fully exempt...... management should facilitate collaboration across scientific disciplines because a plethora of data, originating from basic pharmacodynamics, toxicology, kinetics, and metabolism, as well as from clinical investigations, are involved in a safety pharmacology assessment. Applying formal GLP standards to...

  16. Vibrio vulnificus VvhA induces autophagy-related cell death through the lipid raft-dependent c-Src/NOX signaling pathway

    Science.gov (United States)

    Song, Eun Ju; Lee, Sei-Jung; Lim, Hyeon Su; Kim, Jun Sung; Jang, Kyung Ku; Choi, Sang Ho; Han, Ho Jae

    2016-01-01

    VvhA, a virulent factor of Vibrio (V.) vulnificus, induces acute cell death in a destructive manner. Autophagy plays an important role in cell death, but the functional role of VvhA in autophagy-related cell death has not been elucidated yet. We found that rVvhA significantly increased LC3 puncta formation and autophagic flux in promoting the cell death of human intestinal epithelial Caco-2 cells. The cell death induced by rVvhA was independent of lysosomal permeabilizaton and caspase activation. rVvhA induced rapid phosphorylation of c-Src in the membrane lipid raft, which resulted in an increased interaction between lipid raft molecule caveolin-1 and NADPH oxidase (NOX) complex Rac1 for ROS production. NOX-mediated ROS signaling induced by rVvhA increased the phosphorylation of extracellular signal-regulated kinase (ERK) and eukaryotic translation initiation factor 2α (eIF2α) which are required for mRNA expression of Atg5 and Atg16L1 involved in autophagosome formation. In an in vivo model, VvhA increased autophagy activation and paracellular permeabilization in intestinal epithelium. Collectively, the results here show that VvhA plays a pivotal role in the pathogenesis and dissemination of V. vulnificus by autophagy upregulation, through the lipid raft-mediated c-Src/NOX signaling pathway and ERK/eIF2α activation. PMID:27250250

  17. The interplays between autophagy and apoptosis induced by enterovirus 71.

    Directory of Open Access Journals (Sweden)

    Xueyan Xi

    Full Text Available BACKGROUND: Enterovirus 71 (EV71 is the causative agent of human diseases with distinct severity, from mild hand, foot and mouth disease to severe neurological syndromes, such as encephalitis and meningitis. The lack of understanding of viral pathogenesis as well as lack of efficient vaccine and drugs against this virus impedes the control of EV71 infection. EV71 virus induces autophagy and apoptosis; however, the relationship between EV71-induced autophagy and apoptosis as well as the influence of autophagy and apoptosis on virus virulence remains unclear. METHODOLOGY/PRINCIPAL FINDINGS: In this study, it was observed that the Anhui strain of EV71 induced autophagy and apoptosis in human rhabdomyosarcoma (RD-A cells. Additionally, by either applying chemical inhibitors or knocking down single essential autophagic or apoptotic genes, inhibition of EV71 induced autophagy inhibited the apoptosis both at the autophagosome formation stage and autophagy execution stage. However, inhibition of autophagy at the stage of autophagosome and lysosome fusion promoted apoptosis. In reverse, the inhibition of EV71-induced apoptosis contributed to the conversion of microtubule-associated protein 1 light chain 3-I (LC3-I to LC3-II and degradation of sequestosome 1 (SQSTM1/P62. Furthermore, the inhibition of autophagy in the autophagsome formation stage or apoptosis decreased the release of EV71 viral particles. CONCLUSIONS/SIGNIFICANCE: In conclusion, the results of this study not only revealed novel aspect of the interplay between autophagy and apoptosis in EV71 infection, but also provided a new insight to control EV71 infection.

  18. Autophagy: a new target for nonalcoholic fatty liver disease therapy

    Directory of Open Access Journals (Sweden)

    Mao YQ

    2016-03-01

    Full Text Available Yuqing Mao,1 Fujun Yu,1 Jianbo Wang,2 Chuanyong Guo,3 Xiaoming Fan1 1Department of Gastroenterology and Hepatology, Jinshan Hospital of Fudan University, Shanghai, 2Department of Gastroenterology and Hepatology, The Central Hospital of Lishui City, Wenzhou Medical University, Zhejiang, 3Department of Gastroenterology and Hepatology, Shanghai Tenth People's Hospital, Tongji University, Shanghai, People's Republic of China Abstract: Nonalcoholic fatty liver disease (NAFLD has gained importance in recent decades due to drastic changes in diet, especially in Western countries. NAFLD occurs as a spectrum from simple hepatic steatosis, steatohepatitis to cirrhosis, and even hepatocellular carcinoma. Although the molecular mechanisms underlying the development of NAFLD have been intensively investigated, many issues remain to be resolved. Autophagy is a cell survival mechanism for disposing of excess or defective organelles, and has become a hot spot for research. Recent studies have revealed that autophagy is linked to the development of NAFLD and regulation of autophagy has therapeutic potential. Autophagy reduces intracellular lipid droplets by enclosing them and fusing with lysosomes for degradation. Furthermore, autophagy is involved in attenuating inflammation and liver injury. However, autophagy is regarded as a double-edged sword, as it may also affect adipogenesis and adipocyte differentiation. Moreover, it is unclear as to whether autophagy protects the body from injury or causes diseases and even death, and the association between autophagy and NAFLD remains controversial. This review is intended to discuss, comment, and outline the progress made in this field and establish the possible molecular mechanism involved. Keywords: nonalcoholic fatty liver disease, autophagy, steatosis, steatohepatitis, fibrosis, carcinogenesis

  19. Platycodin-D Induced Autophagy in Non-Small Cell Lung Cancer Cells via PI3K/Akt/mTOR and MAPK Signaling Pathways.

    Science.gov (United States)

    Zhao, Ruolin; Chen, Meijuan; Jiang, Zequn; Zhao, Fengming; Xi, Beili; Zhang, Xu; Fu, Haian; Zhou, Kunfu

    2015-01-01

    Platycodin-D (PD) is an effective triterpene saponin extracted from the root of Platycodon grandiflorum which has been used clinically to treat pulmonary diseases in traditional Chinese medicine. Recently, it has been reported that PD has anti-tumor effects in various cancer models through the induction of apoptosis. However, whether PD induces autophagy in both cell lines and its molecular mechanisms have not been elucidated. Here, our present study confirmed that PD induced autophagy in both NCI-H460 and A549 cells via up-regulating the expression levels of Atg-3, Atg-7 and Beclin-1. Meanwhile, PD contributed to the up-regulation of LC3-II at both protein and mRNA levels. Further detection of the PI3K/Akt/mTOR signaling pathway compared to LY294002 (PI3K kinase inhibitor), RAP (mTOR kinase inhibitor) and insulin (an activator of PI3K/Akt/mTOR signaling pathway) showed that PD induced autophagy through inhibiting the pathway at p-Akt (Ser473), p-p70S6K (Thr389) and p-4EBP1 (Thr37/46) in both cell lines. Moreover, the examination of MAPK signaling pathway showed that PD treatment increased the phosphorylation of JNK and p38 MAPK, while decreased the phosphorylation of Erk1/2 in both cell lines. Additionally, the effects assessed with a panel of pharmacologic inhibitors, including U0126 (Erk1/2 kinase inhibitor), SP600125 (JNK kinase inhibitor) and SB203580 (p38 MAPK kinase inhibitor) suggested that the activation of JNK and p38 MAPK participated in PD-induced autophagy. Taken together, these findings suggested that PD induced autophagy in NCI-H460 and A549 cells through inhibiting PI3K/Akt/mTOR signaling pathway and activating JNK and p38 MAPK signaling pathways. Therefore, PD may be an alternative compound for NSCLC therapy. PMID:26078792

  20. Role of autophagy in acute myeloid leukemia therapy

    Institute of Scientific and Technical Information of China (English)

    Su-Ping Zhang; Yu-Na Niu; Na Yuan; Ai-Hong Zhang; Dan Chao; Qiu-Ping Xu; Li-Jun Wang

    2013-01-01

    Despite its dual role in determining cell fate in a wide array of solid cancer cell lines,autophagy has been robustly shown to suppress or kill acute myeloid leukemia cells via degradation of the oncogenic fusion protein that drives leukemogenesis.However,autophagy also induces the demise of acute leukemia cells that do not express the known fusion protein,though the molecular mechanism remains elusive.Nevertheless,since it can induce cooperation with apoptosis and differentiation in response to autophagic signals,autophagy can be manipulated for a better therapy on acute myeloid leukemia.

  1. Autophagy in HCV Infection: Keeping Fat and Inflammation at Bay

    Directory of Open Access Journals (Sweden)

    Tiziana Vescovo

    2014-01-01

    Full Text Available Hepatitis C virus (HCV infection is one of the main causes of chronic liver disease. Viral persistence and pathogenesis rely mainly on the ability of HCV to deregulate specific host processes, including lipid metabolism and innate immunity. Recently, autophagy has emerged as a cellular pathway, playing a role in several aspects of HCV infection. This review summarizes current knowledge on the molecular mechanisms that link the HCV life cycle with autophagy machinery. In particular, we discuss the role of HCV/autophagy interaction in dysregulating inflammation and lipid homeostasis and its potential for translational applications in the treatment of HCV-infected patients.

  2. ER stress, autophagy, and RNA viruses

    Directory of Open Access Journals (Sweden)

    Jia-Rong eJheng

    2014-08-01

    Full Text Available Endoplasmic reticulum (ER stress is a general term for representing the pathway by which various stimuli affect ER functions. ER stress induces the evolutionarily conserved signaling pathways, called the unfolded protein response (UPR, which compromises the stimulus and then determines whether the cell survives or dies. In recent years, ongoing research has suggested that these pathways may be linked to the autophagic response, which plays a key role in the cell’s response to various stressors. Autophagy performs a self-digestion function, and its activation protects cells against certain pathogens. However, the link between the UPR and autophagy may be more complicated. These two systems may act dependently, or the induction of one system may interfere with the other. Experimental studies have found that different viruses modulate these mechanisms to allow them to escape the host immune response or, worse, to exploit the host’s defense to their advantage; thus, this topic is a critical area in antiviral research. In this review, we summarize the current knowledge about how RNA viruses, including influenza virus, poliovirus, coxsackievirus, enterovirus 71, Japanese encephalitis virus, hepatitis C virus, and dengue virus, regulate these processes. We also discuss recent discoveries and how these will produce novel strategies for antiviral treatment.

  3. Teaching Pharmacology by Case Study.

    Science.gov (United States)

    Jordan, Sue

    1997-01-01

    Using pharmacology case studies with nursing students encourages theory-practice links and infuses real-life content. Cases provide rich qualitative data for evaluating curriculum. However, they are not a substitute for evidence-based practice. (SK)

  4. NASA 2010 Pharmacology Evidence Review

    Science.gov (United States)

    Steinberg, Susan

    2011-01-01

    In 2008, the Institute of Medicine reviewed NASA's Human Research Program Evidence in assessing the Pharmacology risk identified in NASA's Human Research Program Requirements Document (PRD). Since this review there was a major reorganization of the Pharmacology discipline within the HRP, as well as a re-evaluation of the Pharmacology evidence. This panel is being asked to review the latest version of the Pharmacology Evidence Report. Specifically, this panel will: (1) Appraise the descriptions of the human health-related risk in the HRP PRD. (2) Assess the relevance and comprehensiveness of the evidence in identifying potential threats to long-term space missions. (3) Assess the associated gaps in knowledge and identify additional areas for research as necessary.

  5. mir-30d Regulates multiple genes in the autophagy pathway and impairs autophagy process in human cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaojun [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Department of General Surgery, Gansu Provincial Hospital, Lanzhou, Gansu 710000 (China); Zhong, Xiaomin [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011 (China); Tanyi, Janos L.; Shen, Jianfeng [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Xu, Congjian [Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011 (China); Gao, Peng [Department of General Surgery, Gansu Provincial Hospital, Lanzhou, Gansu 710000 (China); Zheng, Tim M. [Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104 (United States); DeMichele, Angela [Division of Hematology and Oncology, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104 (United States); Zhang, Lin, E-mail: linzhang@mail.med.upenn.edu [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States)

    2013-02-15

    Highlights: ► Gene set enrichment analysis indicated mir-30d might regulate the autophagy pathway. ► mir-30d represses the expression of BECN1, BNIP3L, ATG12, ATG5 and ATG2. ► BECN1, BNIP3L, ATG12, ATG5 and ATG2 are direct targets of mir-30d. ► mir-30d inhibits autophagosome formation and LC3B-I conversion to LC3B-II. ► mir-30d regulates the autophagy process. -- Abstract: In human epithelial cancers, the microRNA (miRNA) mir-30d is amplified with high frequency and serves as a critical oncomir by regulating metastasis, apoptosis, proliferation, and differentiation. Autophagy, a degradation pathway for long-lived protein and organelles, regulates the survival and death of many cell types. Increasing evidence suggests that autophagy plays an important function in epithelial tumor initiation and progression. Using a combined bioinformatics approach, gene set enrichment analysis, and miRNA target prediction, we found that mir-30d might regulate multiple genes in the autophagy pathway including BECN1, BNIP3L, ATG12, ATG5, and ATG2. Our further functional experiments demonstrated that the expression of these core proteins in the autophagy pathway was directly suppressed by mir-30d in cancer cells. Finally, we showed that mir-30d regulated the autophagy process by inhibiting autophagosome formation and LC3B-I conversion to LC3B-II. Taken together, our results provide evidence that the oncomir mir-30d impairs the autophagy process by targeting multiple genes in the autophagy pathway. This result will contribute to understanding the molecular mechanism of mir-30d in tumorigenesis and developing novel cancer therapy strategy.

  6. mir-30d Regulates multiple genes in the autophagy pathway and impairs autophagy process in human cancer cells

    International Nuclear Information System (INIS)

    Highlights: ► Gene set enrichment analysis indicated mir-30d might regulate the autophagy pathway. ► mir-30d represses the expression of BECN1, BNIP3L, ATG12, ATG5 and ATG2. ► BECN1, BNIP3L, ATG12, ATG5 and ATG2 are direct targets of mir-30d. ► mir-30d inhibits autophagosome formation and LC3B-I conversion to LC3B-II. ► mir-30d regulates the autophagy process. -- Abstract: In human epithelial cancers, the microRNA (miRNA) mir-30d is amplified with high frequency and serves as a critical oncomir by regulating metastasis, apoptosis, proliferation, and differentiation. Autophagy, a degradation pathway for long-lived protein and organelles, regulates the survival and death of many cell types. Increasing evidence suggests that autophagy plays an important function in epithelial tumor initiation and progression. Using a combined bioinformatics approach, gene set enrichment analysis, and miRNA target prediction, we found that mir-30d might regulate multiple genes in the autophagy pathway including BECN1, BNIP3L, ATG12, ATG5, and ATG2. Our further functional experiments demonstrated that the expression of these core proteins in the autophagy pathway was directly suppressed by mir-30d in cancer cells. Finally, we showed that mir-30d regulated the autophagy process by inhibiting autophagosome formation and LC3B-I conversion to LC3B-II. Taken together, our results provide evidence that the oncomir mir-30d impairs the autophagy process by targeting multiple genes in the autophagy pathway. This result will contribute to understanding the molecular mechanism of mir-30d in tumorigenesis and developing novel cancer therapy strategy

  7. [Pharmacology of bone resorption inhibitor].

    Science.gov (United States)

    Menuki, Kunitaka; Sakai, Akinori

    2015-10-01

    Currently, bone resorption inhibitor is mainly used for osteoporosis. A number of these agents have been developed. These pharmacological action are various. Bisphosphonate inhibit functions of the osteoclasts by inducing apoptosis. On the one hand, RANK-ligand inhibitor and selective estrogen receptor modulator inhibit formation of osteoclasts. It is important to understand these pharmacological action for the selection of the appropriate medicine. PMID:26529923

  8. Autophagy in pancreatic acinar cells in caerulein-treated mice: immunolocalization of related proteins and their potential as markers of pancreatitis.

    Science.gov (United States)

    Zhang, Leshuai; Zhang, Jun; Shea, Katherine; Xu, Lin; Tobin, Grainne; Knapton, Alan; Sharron, Stewart; Rouse, Rodney

    2014-01-01

    Drug-induced pancreatitis (DIP) is an underdiagnosed condition that lacks sensitive and specific biomarkers. To better understand the mechanisms of DIP and to identify potential tissue biomarkers, we studied experimental pancreatitis induced in male C57BL/6 mice by intraperitoneal injection of caerulein (10 or 50 μg/kg) at 1-hr intervals for a total of 7 injections. Pancreata from caerulein-treated mice exhibited consistent acinar cell autophagy and apoptosis with infrequent necrosis. Kinetic assays for serum amylase and lipase also showed a dose-dependent increase. Terminal deoxynucleotidyl transferase-mediated biotin-dNTP nick labeling (TUNEL) detected dose-dependent acinar cell apoptosis. By light microscopy, autophagy was characterized by the formation of autophagosomes and autolysosomes (ALs) within the cytoplasm of acinar cells. Immunohistochemical studies with specific antibodies for proteins related to autophagy and pancreatic stress were conducted to evaluate these proteins as potential biomarkers of pancreatitis. Western blots were used to confirm immunohistochemical results using pancreatic lysates from control and treated animals. Autophagy was identified as a contributing process in caerulein-induced pancreatitis and proteins previously associated with autophagy were upregulated following caerulein treatment. Autophagosomes and ALs were found to be a common pathway, in which cathepsins, lysosome-associated membrane protein 2, vacuole membrane protein 1, microtubule-associated protein 1 light chain 3 (LC3), autophagy-related protein 9, Beclin1, and pancreatitis-associated proteins were simultaneously involved in response to caerulein stimulus. Regenerating islet-derived 3 gamma (Reg3γ), a pancreatic acute response protein, was dose-dependently induced in caerulein-treated mice and colocalized with the autophagosomal marker, LC3. This finding supports Reg3γ as a candidate biomarker for pancreatic injury. PMID:23640381

  9. Roles of oxidative stress and the ERK1/2, PTEN and p70S6K signaling pathways in arsenite-induced autophagy.

    Science.gov (United States)

    Huang, Ya-Chun; Yu, Hsin-Su; Chai, Chee-Yin

    2015-12-15

    Studies show that arsenite induces oxidative stress and modifies cellular function via phosphorylation of proteins and inhibition of DNA repair enzymes. Autophagy, which has multiple physiological and pathological roles in cellular function, is initiated by oxidative stress and is regulated by the signaling pathways of phosphatidylinositol 3-phosphate kinase (PI3K)/mammalian target of rapamycin (mTOR)/p70S6 kinase (p70S6K) and extracellular signaling-regulated protein kinase 1/2 (ERK1/2) that play important roles in oncogenesis. However, the effects of arsenite-induced oxidative stress on autophagy and on expression of related proteins are not fully understood. This study found that cells treated with sodium arsenite had reduced 8-oxoguanine DNA glycosylase 1 (OGG1) and increased 8-hydroxy-2'-deoxyguanosine (8-OHdG) and activating transcription factor (ATF) 3 in SV-40 immortalized human uroepithelial (SV-HUC-1) cells. Arsenite also increased the number of autophagosomes and increased levels of the autophagy markers Beclin-1 and microtubule-associated protein 1 light chain 3B. Reactive oxygen species scavenger decreased arsenite-induced autophagy in SV-HUC-1 cells. Our previous work showed that arsenite induced phosphorylation of the ERK1/2 signaling pathway. The current study further showed that arsenite decreased phosphatase and tensin homologue (PTEN) levels and increased phospho-p70S6 kinase (p-p70S6K) in SV-HUC-1 cells. However, both kinase inhibitor U0126 and the DNA (cytosine-5-)-methyltransferase 1 (DNMT1) inhibitor 5-aza-deoxycytidine abolished the effect of arsenite on expressions of PTEN and p-p70S6K. These results show that autophagy induced by arsenite exposure is mediated by oxidative stress, which regulates activation of the PTEN, p70S6K and ERK1/2 signaling pathways. Thus, this study clarifies the role of autophagy in arsenite-induced urothelial carcinogenesis. PMID:26432159

  10. Rev-erb-α modulates skeletal muscle oxidative capacity by regulating mitochondrial biogenesis and autophagy

    Science.gov (United States)

    Woldt, Estelle; Sebti, Yasmine; Solt, Laura A.; Duhem, Christian; Lancel, Steve; Eeckhoute, Jérôme; Hesselink, Matthijs K.C.; Paquet, Charlotte; Delhaye, Stéphane; Shin, Youseung; Kamenecka, Theodore M.; Schaart, Gert; Lefebvre, Philippe; Nevière, Rémi; Burris, Thomas P.; Schrauwen, Patrick; Staels, Bart; Duez, Hélène

    2013-01-01

    The nuclear receptor Rev-erb-α modulates hepatic lipid and glucose metabolism, adipogenesis and the inflammatory response in macrophages. We show here that Rev-erb-α is highly expressed in oxidative skeletal muscle and plays a role in mitochondrial biogenesis and oxidative function, in gain- and loss-of function studies. Rev-erb-α-deficiency in skeletal muscle leads to reduced mitochondrial content and oxidative function, resulting in compromised exercise capacity. This phenotype was recapitulated in isolated fibers and in muscle cells upon Rev-erbα knock-down, while Rev-erb-α over-expression increased the number of mitochondria with improved respiratory capacity. Rev-erb-α-deficiency resulted in deactivation of the Stk11–Ampk–Sirt1–Ppargc1-α signaling pathway, whereas autophagy was up-regulated, resulting in both impaired mitochondrial biogenesis and increased clearance. Muscle over-expression or pharmacological activation of Rev-erb-α increased respiration and exercise capacity. This study identifies Rev-erb-α as a pharmacological target which improves muscle oxidative function by modulating gene networks controlling mitochondrial number and function. PMID:23852339

  11. Detection of Autophagy in Caenorhabditis elegans Using GFP::LGG-1 as an Autophagy Marker.

    Science.gov (United States)

    Palmisano, Nicholas J; Meléndez, Alicia

    2016-01-01

    In yeast and mammalian cells, the autophagy protein Atg8/LC3 (microtubule-associated proteins 1A/1B light chain 3B encoded by MAP1LC3B) has been the marker of choice to detect double-membraned autophagosomes that are produced during the process of autophagy. A lipid-conjugated form of Atg8/LC3B is localized to the inner and outer membrane of the early-forming structure known as the phagophore. During maturation of autophagosomes, Atg8/LC3 bound to the inner autophagosome membrane remains in situ as the autophagosomes fuse with lysosomes. The nematode Caenorhabditis elegans is thought to conduct a similar process, meaning that tagging the nematode ortholog of Atg8/LC3-known as LGG-1-with a fluorophore has become a widely accepted method to visualize autophagosomes. Under normal growth conditions, GFP-modified LGG-1 displays a diffuse expression pattern throughout a variety of tissues, whereas, when under conditions that induce autophagy, the GFP::LGG-1 tag labels positive punctate structures, and its overall level of expression increases. Here, we present a protocol for using fluorescent reporters of LGG-1 coupled to GFP to monitor autophagosomes in vivo. We also discuss the use of alternative fluorescent markers and the possible utility of the LGG-1 paralog LGG-2. PMID:26729905

  12. Autophagy as a Therapeutic Target in Cardiovascular Disease

    Science.gov (United States)

    Nemchenko, Andriy; Chiong, Mario; Turer, Aslan; Lavandero, Sergio; Hill, Joseph A.

    2011-01-01

    The epidemic of heart failure continues apace, and development of novel therapies with clinical efficacy has lagged. Now, important insights into the molecular circuitry of cardiovascular autophagy have raised the prospect that this cellular pathway of protein quality control may be a target of clinical relevance. Whereas basal levels of autophagy are required for cell survival, excessive levels – or perhaps distinct forms of autophagic flux – contribute to disease pathogenesis. Our challenge will be to distinguish mechanisms that drive adaptive versus maladaptive autophagy and to manipulate those pathways for therapeutic gain. Recent evidence suggests this may be possible. Here, we review the fundamental biology of autophagy and its role in a variety of forms of cardiovascular disease. We discuss ways in which this evolutionarily conserved catabolic mechanism can be manipulated, discuss studies presently underway in heart disease, and provide our perspective on where this exciting field may lead in the future. PMID:21723289

  13. Autophagy in Skeletal Muscle Homeostasis and in Muscular Dystrophies

    Directory of Open Access Journals (Sweden)

    Paolo Bonaldo

    2012-07-01

    Full Text Available Skeletal muscles are the agent of motion and one of the most important tissues responsible for the control of metabolism. The maintenance of muscle homeostasis is finely regulated by the balance between catabolic and anabolic process. Macroautophagy (or autophagy is a catabolic process that provides the degradation of protein aggregation and damaged organelles through the fusion between autophagosomes and lysosomes. Proper regulation of the autophagy flux is fundamental for the homeostasis of skeletal muscles during physiological situations and in response to stress. Defective as well as excessive autophagy is harmful for muscle health and has a pathogenic role in several forms of muscle diseases. This review will focus on the role of autophagy in muscle homeostasis and diseases.

  14. Autophagy: A new therapeutic target for liver fibrosis.

    Science.gov (United States)

    Mao, Yu-Qing; Fan, Xiao-Ming

    2015-08-01

    Hepatic fibrosis is a wound-healing response to liver injury and the result of imbalance of extracellular matrix (ECM) accumulation and degradation. The relentless production and progressive accumulation of ECM can lead to end-stage liver disease. Although significant progress has been achieved in elucidating the mechanisms of fibrogenesis, effective anti-fibrotic strategies are still lacking. Autophagy is an intracellular process of self-digestion of defective organelles to provide material recycling or energy for cell survival. Autophagy has been implicated in the pathophysiology of many human disorders including hepatic fibrosis. However, the exact relationships between autophagy and hepatic fibrosis are not totally clear and need further investigations. A new therapeutic target for liver fibrosis could be developed with a better understanding of autophagy. PMID:26261688

  15. Role of autophagy in liver physiology and pathophysiology

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Autophagy is a highly conserved intracellular degradation pathway by which bulk cytoplasm and superfluous or damaged organelles are enveloped by double membrane structures termed autophagosomes. The autophago-somes then fuse with lysosomes for degradation of their contents, and the resulting amino acids can then recycle back to the cytosol. Autophagy is normally activated in response to nutrient deprivation and other stressors and occurs in all eukaryotes. In addition to maintaining energy and nutrient balance in the liver, it is now clear that autophagy plays a role in liver protein aggregates related diseases, hepatocyte cell death, steatohepatitis, hepatitis virus infection and hepatocellular carcinoma. In this review, I discuss the recent findings of autophagy with a focus on its role in liver pathophysiology.

  16. Glucocorticoids induce autophagy in rat bone marrow mesenchymal stem cells

    DEFF Research Database (Denmark)

    Wang, L.; Fan, J.; Lin, Y. S.;

    2015-01-01

    and their responses to diverse stimuli, however, the role of autophagy in glucocorticoidinduced damage to bone marrow mesenchymal stem cells (BMSCs) remains unclear. The current study confirmed that glucocorticoid administration impaired the proliferation of BMSCs. Transmission electron microscopy...

  17. Methods for the Detection of Autophagy in Mammalian Cells.

    Science.gov (United States)

    Zhang, Ziyan; Singh, Rajat; Aschner, Michael

    2016-01-01

    Macroautophagy (hereafter referred to as autophagy) is a degradation pathway that delivers cytoplasmic materials to lysosomes via double-membraned vesicles designated autophagosomes. Cytoplasmic constituents are sequestered into autophagosomes, which subsequently fuse with lysosomes, where the cargo is degraded. Autophagy is a crucial mechanism involved in many aspects of cell function, including cellular metabolism and energy balance; alterations in autophagy have been linked to various human pathological processes. Thus, methods that accurately measure autophagic activity are necessary. In this unit, we introduce several approaches to analyze autophagy in mammalian cells, including immunoblotting analysis of LC3 and p62, detection of autophagosome formation by fluorescence microscopy, and monitoring autophagosome maturation by tandem mRFP-GFP fluorescence microscopy. Overall, we recommend a combined use of multiple methods to accurately assess the autophagic activity in any given biological setting. © 2016 by John Wiley & Sons, Inc. PMID:27479363

  18. Multiple sclerosis: general features and pharmacologic approach

    International Nuclear Information System (INIS)

    Multiple sclerosis is an autoimmune, inflammatory and desmyelinization disease central nervous system (CNS) of unknown etiology and critical evolution. There different etiological hypotheses talking of a close interrelation among predisposing genetic factors and dissimilar environmental factors, able to give raise to autoimmune response at central nervous system level. Hypothesis of autoimmune pathogeny is based on study of experimental models, and findings in biopsies of affected patients by disease. Accumulative data report that the oxidative stress plays a main role in pathogenesis of multiple sclerosis. Oxygen reactive species generated by macrophages has been involved as mediators of demyelinization and of axon damage, in experimental autoimmune encephalomyelitis and strictly in multiple sclerosis. Disease diagnosis is difficult because of there is not a confirmatory unique test. Management of it covers the treatment of acute relapses, disease modification, and symptoms management. These features require an individualized approach, base on evolution of this affection, and tolerability of treatments. In addition to diet, among non-pharmacologic treatments for multiple sclerosis it is recommended physical therapy. Besides, some clinical assays have been performed in which we used natural extracts, nutrition supplements, and other agents with promising results. Pharmacology allowed neurologists with a broad array of proved effectiveness drugs; however, results of research laboratories in past years make probable that therapeutical possibilities increase notably in future. (Author)

  19. Are mitochondrial reactive oxygen species required for autophagy?

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Jianfei, E-mail: jjf73@pitt.edu [Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh (United States); Maeda, Akihiro; Ji, Jing [Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh (United States); Baty, Catherine J.; Watkins, Simon C. [Center for Biologic Imaging, Department of Cell Biology and Physiology, University of Pittsburgh (United States); Greenberger, Joel S. [Department of Radiation Oncology, University of Pittsburgh (United States); Kagan, Valerian E., E-mail: kagan@pitt.edu [Center for Free Radical and Antioxidant Health, Department of Environmental and Occupational Health, University of Pittsburgh (United States)

    2011-08-19

    Highlights: {yields} Autophageal and apoptotic pathways were dissected in cytochrome c deficient cells. {yields} Staurosporine (STS)-induced autophagy was not accompanied by ROS generation. {yields} Autophagy was detectable in mitochondrial DNA deficient {rho}{sup 0} cells. {yields} Mitochondrial ROS are not required for the STS-induced autophagy in HeLa cells. -- Abstract: Reactive oxygen species (ROS) are said to participate in the autophagy signaling. Supporting evidence is obscured by interference of autophagy and apoptosis, whereby the latter heavily relies on ROS signaling. To dissect autophagy from apoptosis we knocked down expression of cytochrome c, the key component of mitochondria-dependent apoptosis, in HeLa cells using shRNA. In cytochrome c deficient HeLa1.2 cells, electron transport was compromised due to the lack of electron shuttle between mitochondrial respiratory complexes III and IV. A rapid and robust LC3-I/II conversion and mitochondria degradation were observed in HeLa1.2 cells treated with staurosporine (STS). Neither generation of superoxide nor accumulation of H{sub 2}O{sub 2} was detected in STS-treated HeLa1.2 cells. A membrane permeable antioxidant, PEG-SOD, plus catalase exerted no effect on STS-induced LC3-I/II conversion and mitochondria degradation. Further, STS caused autophagy in mitochondria DNA-deficient {rho}{sup o} HeLa1.2 cells in which both electron transport and ROS generation were completely disrupted. Counter to the widespread view, we conclude that mitochondrial ROS are not required for the induction of autophagy.

  20. Autophagy in Skeletal Muscle Homeostasis and in Muscular Dystrophies

    OpenAIRE

    Paolo Bonaldo; Paolo Grumati

    2012-01-01

    Skeletal muscles are the agent of motion and one of the most important tissues responsible for the control of metabolism. The maintenance of muscle homeostasis is finely regulated by the balance between catabolic and anabolic process. Macroautophagy (or autophagy) is a catabolic process that provides the degradation of protein aggregation and damaged organelles through the fusion between autophagosomes and lysosomes. Proper regulation of the autophagy flux is fundamental for the homeostasis o...

  1. Autophagy as a new therapeutic target in Duchenne muscular dystrophy

    OpenAIRE

    Palma, C.; F. Morisi; Cheli, S; S. Pambianco; Cappello, V; Vezzoli, M; Rovere-Querini, P; Moggio, M; Ripolone, M.; Francolini, M; Sandri, M.; Clementi, E

    2012-01-01

    A resolutive therapy for Duchene muscular dystrophy, a severe degenerative disease of the skeletal muscle, is still lacking. Because autophagy has been shown to be crucial in clearing dysfunctional organelles and in preventing tissue damage, we investigated its pathogenic role and its suitability as a target for new therapeutic interventions in Duchenne muscular dystrophy (DMD). Here we demonstrate that autophagy is severely impaired in muscles from patients affected by DMD and mdx mice, a mo...

  2. Hypoxic Preconditioning Alleviates Ethanol Neurotoxicity: the Involvement of Autophagy

    OpenAIRE

    Wang, Haiping; Bower, Kimberly A.; Frank, Jacqueline A.; Xu, Mei; Luo, Jia

    2013-01-01

    Ethanol is a neuroteratogen and neurodegeneration is the most devastating consequence of developmental exposure to ethanol. A sublethal preconditioning has been proposed as a neuroprotective strategy against several central nervous system (CNS) neurodegenerative diseases. We have recently demonstrated that autophagy is a protective response to alleviate ethanol toxicity. A modest hypoxic preconditioning (1% oxygen) did not cause neurotoxicity but induced autophagy (Tzeng et al., 2010). We the...

  3. Are mitochondrial reactive oxygen species required for autophagy?

    International Nuclear Information System (INIS)

    Highlights: → Autophageal and apoptotic pathways were dissected in cytochrome c deficient cells. → Staurosporine (STS)-induced autophagy was not accompanied by ROS generation. → Autophagy was detectable in mitochondrial DNA deficient ρ0 cells. → Mitochondrial ROS are not required for the STS-induced autophagy in HeLa cells. -- Abstract: Reactive oxygen species (ROS) are said to participate in the autophagy signaling. Supporting evidence is obscured by interference of autophagy and apoptosis, whereby the latter heavily relies on ROS signaling. To dissect autophagy from apoptosis we knocked down expression of cytochrome c, the key component of mitochondria-dependent apoptosis, in HeLa cells using shRNA. In cytochrome c deficient HeLa1.2 cells, electron transport was compromised due to the lack of electron shuttle between mitochondrial respiratory complexes III and IV. A rapid and robust LC3-I/II conversion and mitochondria degradation were observed in HeLa1.2 cells treated with staurosporine (STS). Neither generation of superoxide nor accumulation of H2O2 was detected in STS-treated HeLa1.2 cells. A membrane permeable antioxidant, PEG-SOD, plus catalase exerted no effect on STS-induced LC3-I/II conversion and mitochondria degradation. Further, STS caused autophagy in mitochondria DNA-deficient ρo HeLa1.2 cells in which both electron transport and ROS generation were completely disrupted. Counter to the widespread view, we conclude that mitochondrial ROS are not required for the induction of autophagy.

  4. Epigenetic Regulation of Autophagy by the Methyltransferase G9a

    OpenAIRE

    Artal-Martinez de Narvajas, Amaia; Gomez, Timothy S.; Zhang, Jin-San; Mann, Alexander O.; Taoda, Yoshiyuki; Gorman, Jacquelyn A.; Herreros-Villanueva, Marta; Gress, Thomas M; Ellenrieder, Volker; Bujanda, Luis; Kim, Do-Hyung; Kozikowski, Alan P.; Koenig, Alexander; Billadeau, Daniel D.

    2013-01-01

    Macroautophagy is an evolutionarily conserved cellular process involved in the clearance of proteins and organelles. Although the cytoplasmic machinery that orchestrates autophagy induction during starvation, hypoxia, or receptor stimulation has been widely studied, the key epigenetic events that initiate and maintain the autophagy process remain unknown. Here we show that the methyltransferase G9a coordinates the transcriptional activation of key regulators of autophagosome formation by remo...

  5. Autophagy is essential for mouse sense of balance

    OpenAIRE

    Mariño García, Guillermo; Fernández Fernández, Álvaro; Cabrera Benítez, María Sandra; Cabanillas Farpón, Rubén; Francisco RODRÍGUEZ; Salvador Montoliu, Natalia; Fueyo Silva, Antonio Manuel; Lundberg, Yunxia W.; Vega Álvarez, José Antonio; Germanà, Antonino; Pérez Freije, José María; López Otín, Carlos

    2010-01-01

    Autophagy is an evolutionarily conserved process that is essential for cellular homeostasis and organismal viability in eukaryotes. However, the extent of its functions in higher-order processes of organismal physiology and behavior is still unknown. Here, we report that autophagy is essential for the maintenance of balance in mice and that its deficiency leads to severe balance disorders. We generated mice deficient in autophagin-1 protease (Atg4b) and showed that they had substantial system...

  6. Linking ER Stress to Autophagy: Potential Implications for Cancer Therapy

    OpenAIRE

    Tom Verfaillie; Maria Salazar; Guillermo Velasco; Patrizia Agostinis

    2010-01-01

    Different physiological and pathological conditions can perturb protein folding in the endoplasmic reticulum, leading to a condition known as ER stress. ER stress activates a complex intracellular signal transduction pathway, called unfolded protein response (UPR). The UPR is tailored essentially to reestablish ER homeostasis also through adaptive mechanisms involving the stimulation of autophagy. However, when persistent, ER stress can switch the cytoprotective functions of U