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Objective— Recent studies suggested the occurrence of phenotypic switching of vascular smooth muscle cells (VSMCs) during the development of aortic aneurysm (AA). However, lineage-tracing studies are still lacking, and the behavior of VSMCs during the formation of dissecting AA is poorly understood. Approach and Results— We used multicolor lineage tracing of VSMCs to track their fate after injury in murine models of Ang II (angiotensin II)–induced dissecting AA. We also addressed the direct impact of autophagy on the response of VSMCs to AA dissection. Finally, we studied the relevance of these processes to human AAs. Here, we show that a subset of medial VSMCs undergoes clonal expansion and that VSMC outgrowths are observed in the adventitia and borders of the false channel during Ang II–induced development of dissecting AA. The clonally expanded VSMCs undergo phenotypic switching with downregulation of VSMC differentiation markers and upregulation of phagocytic markers, indicative of functional changes. In particular, autophagy and endoplasmic reticulum stress responses are activated in the injured VSMCs. Loss of autophagy in VSMCs through deletion of autophagy protein 5 gene ( Atg5 ) increases the susceptibility of VSMCs to death, enhances endoplasmic reticulum stress activation, and promotes IRE (inositol-requiring enzyme) 1α-dependent VSMC inflammation. These alterations culminate in increased severity of aortic disease and higher incidence of fatal AA dissection in mice with VSMC-restricted deletion of Atg5 . We also report increased expression of autophagy and endoplasmic reticulum stress markers in VSMCs of human dissecting AAs. Conclusions— VSMCs undergo clonal expansion and phenotypic switching in Ang II–induced dissecting AAs in mice. We also identify a critical role for autophagy in regulating VSMC death and endoplasmic reticulum stress–dependent inflammation with important consequences for aortic wall homeostasis and repair.

Mutations in the macroautophagy/autophagy gene EPG5 are responsible for Vici syndrome, a human genetic disease characterized by combined immunodeficiency. Previously, we found that epg5−/- mice exhibit hyperinflammation in the lungs mediated by IL1B/IL-1β and TNF/TNFα, resulting in resistance to influenza. Here, we find that disruption of Epg5 results in protection against multiple enteric viruses including norovirus and rotavirus. Gene expression analysis reveals IFNL/IFN-λ responsive genes as a key alteration. Further, mice lacking Epg5 exhibit substantial alterations of the intestinal microbiota. Surprisingly, germ-free mouse studies indicate Epg5-associated inflammation of both the intestine and lung is microbiota-independent. Genetic studies support IFNL signaling as the primary mediator of resistance to enteric viruses, but not of microbial dysbiosis, in epg5−/- mice. This study unveils an important role, unexpectedly independent of the microbiota, for autophagy gene Epg5 in host organism protection by modulating intestinal IFNL responses. Abbreviations: CTNNB1: catenin (cadherin associated protein), beta 1; DAPI: 4′,6-diamidino-2-phenylindole; EPG5: ectopic P-granules autophagy protein 5 homolog (C. elegans); FT: fecal transplant; IFI44: interferon-induced protein 44; IFIT1: interferon-induced protein with tetratricopeptide repeats 1; IFNG/IFN-γ: interferon gamma; IFNL/IFN-λ: interferon lambda; IFNLR1: interferon lambda receptor 1; IL1B/IL-1β: interleukin 1 beta; ISG: interferon stimulated gene; GF: germ-free; LEfSe: linear discriminant analysis effect size; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MNoV: murine norovirus; MX2: MX dynamin-like GTPase 2; OAS1A: 2’-5’ oligoadenylate synthetase 1A; RV: rotavirus; SPF: specific-pathogen free; SQSTM1/p62: sequestosome 1; STAT1: signal transducer and activator of transcription 1; STING1: stimulator of interferon response cGAMP interactor 1; TBK1: TANK-binding kinase 1; TNF/TNFα: tumor necrosis factor

Methamphetamine (Meth) is a neuro-stimulator substrate which might lead to neural cell death and the activation of several interconnected cellular pathways as well. However, the precise molecular mechanisms underlying Meth-induced neural cell death remained unclear yet. The current study aimed to assess the specific relationship between long-term Meth exposure and several endoplasmic reticulum stress, autophagy, and apoptosis associated markers including C/EBP homologous protein (CHOP), Tribbles homolog 3(Trib3), Nuclear protein 1(NUPR1), and Beclin-1 expression in postmortem human striatum. Therefore, the effects of long-term Meth exposure on autophagy and apoptosis in the striatum of postmortem users were evaluated and molecular, immunehistochemical, and histological examinations were performed on 10 control and 10 Meth-addicted brains. The level of CHOP, Trib3, NUPR1, and Beclin-1, Microtubule-associated proteins 1A/1B light chain 3B(LC3), Caspase 3, and Autophagy protein 5 (ATG5) were measured by using qPCR and immunohistochemistry. Stereological neural cell counting, Hematoxylin and Eosin, Nissl and Tunel staining were also performed. Based on our findings, the expression level of CHOP, Trib3, NUPR1, and Beclin-1 in the striatum of Meth group were significantly higher than the control group. Besides, the neuronal cell death was substantially increased in the striatum based on data obtained from the Tunel assay and the stereological analysis. Long-term presence of Meth in the brain can induce ER stress and overexpression of NUPR1 which is associated with the upregulation of CHOP, a pro-apoptotic transcription factor. Moreover, an increase in Trib3 expression is implicated in CHOP-dependent autophagic cell death during Meth-induced ER stress accompanied by an increase in neuronal cell death in the striatum of the postmortem human brains. Beclin 1 expression was also upregulated which may due to the activation of autophagic mechanisms upon prolonged Meth exposure.

Epidemiological and animal studies indicate an association between high levels of dietary fat intake and an increased risk of breast cancer. The multifaceted role of autophagy in cancer has been revealed in previous years. However, the mechanism of this role remains unknown. In the present study, the two most common free fatty acids, palmitate acid (PA) and oleic acid (OA), were used to determine the effect on human breast cancer MDA-MB-231 cells, and the possible role of autophagy was investigated by detecting light chain 3 (LC3)-II/I. Bafliomycin A1 was used to detect autophagy flux. High palmitate acid condition-induced MDA-MB-231 cell death and invasion were mitigated by 3-methyladenine pretreatment or transfection with shRNA against autophagy protein 5. By contrast, high oleic acid condition induced MDA-MB-231 cell proliferation, migration and invasion were mitigated using rapamycin. The present results suggest that autophagy has an important role in the effects of PA and OA on breast cancer growth and metastasis in vitro.

Increased deposition of β-amyloid (Aβ) protein is one of the typical characteristics of Alzheimer's disease (AD). Recent evidence has demonstrated that the microRNA let-7 family, which is highly expressed in the central nervous system, participates in the regulation of pathologic processes of AD. In the present study, the effect of let-7a overexpression on Aβ1-40-induced neurotoxicity was evaluated in PC12 and SK-N-SH cells. The results indicated that overexpression of let-7a enhanced the neurotoxicity induced by Aβ1-40 in PC12 and SK-N-SH cells. In addition, the apoptosis induced by Aβ1-40 in PC12 and SK-N-SH cells was increased by let-7a overexpression. Furthermore, Aβ1-40 treatment increased the protein levels of microtubule-associated protein 1A/1B-light chain 3 (LC3) and beclin-1 and increased the LC3 II/I ratio. The mRNA expression levels of beclin-1, autophagy protein 5 (Atg-5) and Atg-7 were also increased by Aβ1-40 treatment in PC12 cells. Let-7a overexpression further upregulated the above autophagy-related markers. Furthermore, the protein level of p62 was increased by Aβ1-40 treatment, and this was further enhanced by let-7a overexpression. Finally, the present results demonstrated that the phosphoinositide-3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway was involved in the autophagy regulation by let-7a. In conclusion, the present study demonstrates that the neurotoxicity induced by Aβ1-40 is augmented by let-7a overexpression via regulation of autophagy, and the PI3K/Akt/mTOR signaling pathway also serves a function in this process.

Summary: Autophagy is a lysosomal degradation pathway with important roles in physiological homeostasis and disease. However, the role of autophagy in intestinal stem cells (ISCs) is unclear. Here, we show that intrinsic autophagy in ISCs is important for ISC homeostasis. Mice lacking autophagy protein 5 (ATG5) in intestinal epithelial cells (iECs) (Villin-Cre: Atg5fl/fl, hereafter Atg5ΔIEC mice) or in all iECs except Paneth cells (Ah-Cre: Atg5fl/fl mice) had significantly fewer ISCs than did control mice and showed impaired ISC-dependent intestinal recovery after irradiation. Crypt ISCs from Atg5ΔIEC mice had significantly higher reactive oxygen species (ROS) levels than did those from control mice. A ROS-inducing reagent decreased the ISC number and impaired ISC regenerative capacity ex vivo, and treating Atg5ΔIEC mice with an antioxidant rescued their defects. Our results show that intrinsic autophagy supports ISC maintenance by reducing excessive ROS. Optimizing autophagy may lead to autophagy-based therapies for intestinal injuries. : Autophagy is a lysosomal degradation pathway with important roles in physiological homeostasis and disease. Asano et al. find that intrinsic autophagy is important for the maintenance of intestinal stem cells by reducing excessive reactive oxygen species. This stem cell maintenance is necessary to provide damage-induced intestinal regeneration. Keywords: intestinal epithelial cell (iEC), intestinal stem cell (ISC), autophagy, reactive oxygen species (ROS), regeneration, irradiation, 5-fluorouracil (5-FU)

Objective Regulated in development and DNA damage response 1 (REDD1) is an endogenous inhibitor of mechanistic target of rapamycin (mTOR) that regulates cellular stress responses. REDD1 expression is decreased in aged and osteoarthritic (OA) cartilage, and it regulates mTOR signaling and autophagy in articular chondrocytes in vitro. This study was undertaken to investigate the effects of REDD1 deletion in vivo using a mouse model of experimental OA. Methods OA severity was histologically assessed in 4-month-old wild-type and REDD1−/− mice subjected to surgical destabilization of the medial meniscus (DMM). Chondrocyte autophagy, apoptosis, mitochondrial content, and expression of mitochondrial biogenesis markers were determined in cartilage and cultured chondrocytes from wild-type and REDD1−/− mice. Results REDD1 deficiency increased the severity of changes in cartilage, menisci, subchondral bone, and synovium in the DMM model of OA. Chondrocyte death was increased in the cartilage of REDD1−/− mice and in cultured REDD1−/− mouse chondrocytes under oxidative stress conditions. Expression of key autophagy markers (microtubule-associated protein 1A/1B light chain 3 and autophagy protein 5) was markedly reduced in cartilage from REDD1−/− mice and in cultured human and mouse chondrocytes with REDD1 depletion. Mitochondrial content, ATP levels, and expression of the mitochondrial biogenesis markers peroxisome proliferator–activated receptor γ coactivator 1α (PGC-1α) and transcription factor A, mitochondrial (TFAM) were also decreased in REDD1-deficient chondrocytes. REDD1 was required for AMP-activated protein kinase–induced PGC-1α in chondrocytes. Conclusion Our findings suggest that REDD1 is a key mediator of cartilage homeostasis through regulation of autophagy and mitochondrial biogenesis and that REDD1 deficiency exacerbates the severity of injury-induced OA.

Arterial calcification is a major complication of cardiovascular disease. Oestrogen replacement therapy in postmenopausal women is associated with lower levels of coronary artery calcification, but its mechanism of action remains unclear. Here, we show that oestrogen inhibits the osteoblastic differentiation of vascular smooth muscle cells (VSMCs) in vitro and arterial calcification in vivo by promoting autophagy. Through electron microscopy, GFP–LC3 redistribution, and immunofluorescence analyses as well as measurement of the expression of the autophagosome marker light-chain I/II (LC3I/II) and autophagy protein 5 (Atg5), we show that autophagy is increased in VSMCs by oestrogen in vitro and in vivo. The inhibitory effect of oestrogen on arterial calcification was counteracted by 3-methyladenine (3MA) or knockdown of Atg5 and was increased by rapamycin. Furthermore, the inhibitory effect of oestrogen on arterial calcification and the degree of autophagy induced by oestrogen were blocked by a nonselective oestrogen receptor (ER) antagonist (ICI 182780), a selective oestrogen receptor alpha (ERα) antagonist (MPP), and ERα-specific siRNA. Our data indicate that oestrogen inhibits the osteoblastic differentiation of VSMCs by promoting autophagy through the ERα signalling pathway in vitro and arterial calcification in vivo by increasing autophagy. Our findings provide new insights into the mechanism by which oestrogen contributes to vascular calcification in vitro and in vivo.

Our previous study demonstrated that thiodigalactoside (TDG) ameliorates obesity by targeted inhibition of galectin-1 (GAL1). Here, for the first time, we report the unexpected role of GAL1 and ATG5 inhibition by TDG in lipid metabolism. Core thermogenic marker proteins and genes were highly induced in white adipose tissue (WAT) of rats fed a high fat diet (HFD) and TDG, resulting in the significant development of brown fat-like adipocytes in inguinal WAT. TDG treatment reduced weight gain and fat mass as well as activated brown adipose tissue (BAT) in HFD-fed rats. TDG also reduced protein levels of LC3-II and increased protein levels of P62, suggesting its possible role in suppression of autophagy. Combined inhibition of GAL1 and ATG5 by TDG treatment protected rats against both HFD-induced adipogenesis as well as lipogenesis, as evidenced by suppression of CCAAT/enhancer-binding protein alpha, peroxisome proliferator-activated receptor gamma and fatty acid synthase. In conclusion, the present findings suggest that TDG plays a role in browning and lipid catabolism by combined inhibition of GAL1 and ATG5 and thus may have potential therapeutic implications in the regulation of energy homeostasis via its action in WAT. © 2017 IUBMB Life, 69(7):510-521, 2017.

Autophagy is a homeostatic process regulating turnover of impaired proteins and organelles, and p62 (sequestosome-1, SQSTM1) functions as the autophagic receptor in this process. p62 also functions as a hub for intracellular signaling such as that in the mammalian target of rapamycin (mTOR) pathway. Liver stem/progenitor cells have the potential to differentiate to form hepatocytes or cholangiocytes. In this study, we examined effects of autophagy, p62, and associated signaling on hepatic differentiation. Adult stem/progenitor cells were isolated from the liver of mice with chemically induced liver injury. Effects of autophagy, p62, and related signaling pathways on hepatic differentiation were investigated by silencing the genes for autophagy protein 5 (ATG5) and/or SQSTM1/p62 using small interfering RNAs. Hepatic differentiation was assessed based on increased albumin and hepatocyte nuclear factor 4α, as hepatocyte markers, and decreased cytokeratin 19 and SOX9, as stem/progenitor cell markers. These markers were measured using quantitative RT-PCR, immunofluorescence, and Western blotting. ATG5 silencing decreased active LC3 and increased p62, indicating inhibition of autophagy. Inhibition of autophagy promoted hepatic differentiation in the stem/progenitor cells. Conversely, SQSTM1/p62 silencing impaired hepatic differentiation. A suggested mechanism for p62-dependent hepatic differentiation in our study was activation of the mTOR pathway by amino acids. Amino acid activation of mTOR signaling was enhanced by ATG5 silencing and suppressed by SQSTM1/p62 silencing. Our findings indicated that promoting amino acid sensitivity of the mTOR pathway is dependent on p62 accumulated by inhibition of autophagy and that this process plays an important role in the hepatic differentiation of stem/progenitor cells. J. Cell. Physiol. 232: 2112-2124, 2017. © 2016 Wiley Periodicals, Inc.

Although many biological functions of activating transcription factor 4 (ATF4) have been identified, a role of hypothalamic ATF4 in the regulation of energy homeostasis is poorly understood. In this study, we showed that hypothalamic proopiomelanocortin (POMC) neuron–specific ATF4 knockout (PAKO) mice are lean and have higher energy expenditure. Furthermore, PAKO mice were resistant to high-fat diet–induced obesity, glucose intolerance, and leptin resistance. Moreover, the expression of autophagy protein 5 (ATG5) was increased or decreased by ATF4 knockdown or overexpression, respectively, and ATF4 inhibited the transcription of ATG5 by binding to the basic zipper-containing protein sites on its promoter. Importantly, mice with double knockout of ATF4 and ATG5 in POMC neurons gained more fat mass and reduced energy expenditure compared with PAKO mice under a high-fat diet. Finally, the effect of ATF4 deletion in POMC neurons was possibly mediated via enhanced ATG5-dependent autophagy and α-melanocyte–stimulating hormone production in the hypothalamus. Taken together, these results identify the beneficial role of hypothalamic ATF4/ATG5 axis in the regulation of energy expenditure, obesity, and obesity-related metabolic disorders, which suggests that ATF4/ATG5 axis in the hypothalamus may be a new potential therapeutic target for treating obesity and obesity-related metabolic diseases.

The antioxidative response mediated by transcription factor NRF2 is thought to be a pivotal cellular defense system against various extrinsic stresses. It has been reported that activation of the NRF2 pathway confers cells with resistance to ionizing radiation-induced damage. However, the underlying mechanism remains largely unknown. In the current research, it was found that α-particle radiation has the ability to stimulate NRF2 expression in human osteosarcoma U-2 OS cells. Knockdown of cellular NRF2 level by shRNA-mediated gene silencing decreased the survival rate, increased the micronucleus formation rate and apoptosis rate in irradiated cells. Consistently, knockdown of NRF2 resulted in decreased expression of p65 and Bcl-2, and increased expression of p53 and Bax. Besides, it was observed that increased expression of NRF2 was partially dependent on radiation induced phosphorylation of ERK 1/2. Further results showed that radiation promoted autophagy flux which leads to the enhanced phosphorylation of ERK 1/2, as evidenced by the resultls that knockdown of ATG5 (Autophagy protein 5) gene by shRNA suppressed both radiation induced ERK 1/2 phosphorylation and NRF2 upregulation. Based on these results, it is proposed that attenuation of NRF2 antioxidative pathway can sensitize U-2 OS cells to radiation, where NRF2 antioxidative response is regulated by autophagy mediated activation of ERK 1/2 kinases.

Autophagy is an important biological activity that maintains homeostasis in eukaryotic cells. However, little is known about the functions of fish autophagy-related genes (Atgs). In this study, we cloned and characterized Atg5, a key gene in the autophagy gene superfamily, from orange-spotted grouper (Epinephelus coioides) (EcAtg5). EcAtg5 encoded a 275-amino acid protein that shared 94 and 81% identity to seabass (Lates calcarifer) and humans (Homo sapiens), respectively. The transcription level of EcAtg5 was significantly increased in cells infected with red-spotted grouper nervous necrosis virus (RGNNV). In cells infected with Singapore grouper iridovirus (SGIV), EcAtg5 expression declined during the early stage of infection and increased in the late stage. Fluorescence microscopy revealed that EcAtg5 mainly localized with a dot-like pattern in the cytoplasm of grouper cells. Overexpression of EcAtg5 significantly increased the replication of RGNNV and SGIV at different levels of detection, as indicated by increased severity of the cytopathic effect, transcription levels of viral genes, and levels of viral proteins. Knockdown of EcAtg5 decreased the replication of RGNNV and SGIV. Further studies showed that overexpression EcAtg5 activated autophagy, decreased expression levels of interferon related cytokines or effectors and pro-inflammatory factors, and inhibited the activation of nuclear factor κB, IFN-sensitive response element, and IFNs. In addition, ectopic expression of EcAtg5 affected cell cycle progression by hindering the G1/S transition. Taken together, our results demonstrated that fish Atg5 exerted a crucial role in virus replication by promoting autophagy, down-regulating antiviral IFN responses, and affecting the cell cycle.

Carbazole alkaloids, a major constituent of Murraya koenigii (L.) Sprengel (Rutaceae), exhibit biological effects such as anticancer activity via the induction of apoptosis, and they represent candidate chemotherapeutic agents. Oral squamous cell carcinoma (OSCC) is the most prevalent cancer of the oral cavity and a growing and serious health problem worldwide. In this study, we investigated the anticancer properties and mechanisms of action of two carbazole alkaloids derived from M. koenigii leaves, mahanine and isomahanine, in the OSCC cell line CLS-354. At 15 μM, mahanine and isomahanine were cytotoxic to CLS-354 cells, triggering apoptosis via caspase-dependent and -independent mechanisms. Autophagosomes, visualised using monodansylcadaverine (MDC) labelling, were numerous in carbazole alkaloid-treated cells. Mahanine and isomahanine markedly induced the expression of the autophagosome marker microtubule-associated protein 1 light chain 3, type II (LC3B-II). Genetic and chemical inhibition of autophagy via silencing of the Autophagy protein 5 gene and exposure to bafilomycin A1 (BafA1), respectively, did not arrest carbazole alkaloid-induced apoptosis, indicating that it occurs independently of autophagic activation. Surprisingly, both carbazole alkaloids caused increased accumulation of p62/sequestosome1 (p62/SQSTM1), with coordinated expression of LC3B-II and cleaved caspase-3, suggesting inhibition of autophagic flux. Our results suggest that inhibition of autophagic flux is associated with carbazole alkaloid-induced apoptosis. Our findings provide evidence of a novel cytotoxic action of natural carbazole alkaloids and support their use as candidate chemotherapeutic agents for the treatment of OSCC.

Hepatocellular carcinoma (HCC) ranks the second cause of cancer-associated mortality worldwide. In the present study, the effects and mechanisms of a new phenolic natural product E-[6′-(5′-hydroxypentyl)tricosyl]-4-hydroxy-3-methoxycinnamate (EHHM) isolated from Livistona chinensis on the growth of HCC cells were investigated. It was observed that EHHM treatment significantly suppressed cell proliferation and colony formation, and induced cell apoptosis via a mitochondria-dependent caspase pathway in HepG2 cells in a time- and dose-dependent manner. Meanwhile, EHHM treatment also led to upregulated expression of autophagy protein 5 (Atg5), Beclin 1 and light chain 3 (LC3)-II proteins, and accumulation of green fluorescent protein-LC3 punctate florescent foci in HCC cells, suggesting that EHHM-induced apoptosis is accompanied by autophagy induction. Western blotting revealed that EHHM-induced autophagy is related to the inhibition of the Akt/mechanistic target of rapamycin/p70 ribosomal protein S6 kinase signaling pathway. Furthermore, treatment with Atg5 small interfering RNA or autophagy inhibitors significantly enhanced EHHM-mediated growth inhibition and apoptotic cell death, indicating that autophagy serves as a self-protective mechanism in EHHM-treated HCC cells, and that combined treatment with EHHM and autophagy inhibitors may be an effective therapeutic strategy for HCC.

Skeletal muscle remodels metabolic capacity, contractile and exercise phenotype in response to physiological demands. This adaptive remodeling response to physical activity can ameliorate/prevent diseases associated with poor diet and lifestyle. Our previous work demonstrated that skeletal muscle-specific transgenic expression of the neuron-derived orphan nuclear receptor, Nor-1 drives muscle reprogramming, improves exercise endurance, and oxidative metabolism. The current manuscript investigates the association between exercise, Nor-1 expression and the role of Nor-1 in adaptive remodeling. We demonstrate that Nor-1 expression is induced by exercise and is dependent on calcium/calcineurin signaling (in vitro and in vivo). Analysis of fatigue-resistant transgenic mice that express Nor-1 in skeletal muscle revealed increased hypertrophy and vascularization of muscle tissue. Moreover, we demonstrate that transgenic Nor-1 expression is associated with increased intracellular recycling, ie, autophagy, involving 1) increased expression of light chain 3A or LC3A-II, autophagy protein 5, and autophagy protein 12 in quadriceps femoris muscle extracts from Tg-Nor-1 (relative to Wild-type (WT) littermates); 2) decreased p62 expression indicative of increased autophagolysosome assembly; and 3) decreased mammalian target of rapamycin complex 1 activity. Transfection of LC3A-GFP-RFP chimeric plasmid demonstrated that autophagolysosome formation was significantly increased by Nor-1 expression. Furthermore, we demonstrated a single bout of exercise induced LC3A-II expression in skeletal muscle from C57BL/6 WT mice. This study, when combined with our previous studies, demonstrates that Nor-1 expression drives multiple physiological changes/pathways that are critical to the beneficial responses of muscle to exercise and provides insights into potential pharmacological manipulation of muscle reprogramming for the treatment of lifestyle induced chronic diseases.

Trichosanthin (TCS), isolated from the root tuber of Trichosanthes kirilowii tubers in the Cucurbitaceae family, owns a great deal of biological and pharmacological activities including anti-virus and anti-tumor. TCS has been reported to induce cell apoptosis of a diversity of cancers, including cervical cancer, choriocarcinoma, and gastric cancer, etc. However, whether TCS would induce autophagy in gastric cancer cells was seldom investigated. In current study, human gastric cancer MKN-45 cell growth was significantly inhibited by TCS. The anti-proliferation effect of TCS was due to an increased autophagy, which was confirmed by monodansylcadervarine (MDC) staining, up-regulation of Autophagy protein 5 (Atg5), and conversion of LC3 I to LC3 II (autophagosome marker). In addition, TCS induced reactive oxygen species (ROS) in MKN-45 cells and ROS scavenger N-acetylcysteine (NAC) significantly reversed TCS-induced autophagy. Furthermore, NF-κB/p53 pathway was activated during the process of autophagy induced by TCS and the ROS generation was mediated by it in MKN-45 cells. In vivo results showed that TCS exerted significantly anti-tumor effect on MKN-45 bearing mice. Considering the clinical usage of TCS on other human diseases, these research progresses provided a new insight into cancer research and new therapeutic avenues for patients with gastric cancer.

Autophagy is not only involved in development, but also has been proved to attend immune response against invading pathogens. Autophagy protein 5 (ATG5) is an important autophagic protein, which plays a crucial role in autophagosome elongation. Although ATG5 has been well studied in mammal, yeast, and Drosophila, little is known about ATG5 in lepidopteran insects. We cloned putative SeAtg5 gene from Spodoptera exigua larvae by the rapid amplification of cDNA ends method, and its characteristics and the influences of multiple exogenous factors on its expression levels were then investigated. The results showed that the putative S. exigua SeATG5 protein is highly homologous to other insect ATG5 proteins, which has a conserved Pfm domain and multiple phosphorylation sites. Next, fluorescence microscope observation showed that mCherry-SeATG5 was distributed in both nucleus and cytoplasm of Spodoptera litura Sl-HP cells and partially co-localized with BmATG6-GFP, but it almost has no significant co-localization with GFP-HaATG8. Then, the Western blot analysis demonstrated that GFP-SeATG5 conjugated with ATG12. Moreover, real-time PCR revealed that its expression levels significantly increased at the initiation of pupation and the stage of adult. In addition, the expression levels of SeAtg5 can be enhanced by the starvation, UV radiation, and infection of baculovirus and bacterium. However, the expression levels of SeAtg5 decreased at 24 h post treatments in all these treatments except in starvation. These results suggested that SeATG5 might be involved in response of S. exigua under various stress conditions.

To elucidate the pathogenesis of rheumatoid arthritis (RA), we used proteomic analysis to determine the protein profile in a synovial cell line, MH7A, established from patients with RA. Proteins were extracted from MH7A cells that were or were not stimulated with tumor necrosis factor‐α (TNF‐α), and then analyzed on a liquid chromatography/mass spectrometry system equipped with a unique long monolithic silica capillary. On the basis of the results of this proteomic analysis, we identified 2650 proteins from untreated MH7A cells and 2688 proteins from MH7A cells stimulated with TNF‐α. Next, we selected 269 differentially produced proteins that were detected only under TNF‐α stimulation, and classified these proteins by performing gene ontology analysis by using DAVID as a functional annotation tool. In TNF‐α‐stimulated MH7A cells, we observed substantial production of plasminogen‐activator inhibitor 2 and apoptosis‐regulating proteins such as BH3‐interacting domain death agonist, autophagy protein 5, apolipoprotein E, and caspase‐3. These results indicate that the upregulation of plasminogen‐activator inhibitor 2 and apoptosis‐regulating proteins in synovial cells in response to TNF‐α stimulation might represent a predominant factor that contributes to the pathogenesis of RA.

Macrophage migration inhibitory factor (MIF) is an anti‑apoptotic agent in various cell types and protects the heart from stress‑induced injury by modulating autophagy. Autophagy, a conserved pathway for bulk degradation of intracellular proteins and organelles, helps to preserve and recycle energy and nutrients for cells to survive during starvation. The present study hypothesized that MIF protects bone marrow‑derived mesenchymal stem cells (MSCs) from apoptosis by modulating autophagy via the AMP‑activated protein kinase/mammalian target of rapamycin (AMPK/mTOR) signaling pathway. MSCs were obtained from rat bone marrow and cultured. Apoptosis was induced by hypoxia/serum deprivation for 24 h and was assessed using flow cytometry. MIF protected MSCs from apoptosis by modulating autophagy via the AMPK/mTOR signaling pathway resulting in increased expression of autophagy‑associated proteins (including LC3BI/LC3BII, Beclin‑1 and autophagy protein 5), and by increased phosphorylation of AMPK and decreased phosphorylation of mTOR. The MIF anti‑apoptotic effects were blocked by autophagy inhibitor, 3‑methyladenine or AMPK inhibitor, Compound C. These results indicate that MIF exerts a permissive role in protecting MSCs from apoptosis by regulation of autophagy via the AMPK/mTOR signaling pathway.

Autophagy is essential for cell survival under stress and has also been implicated in host defense. Here, we investigated the interactions between Leishmania donovani, the main etiological agent of visceral leishmaniasis, and the autophagic machinery of human macrophages. Our results revealed that during early infection—and via activation of the Akt pathway—Leishmania actively inhibits the induction of autophagy. However, by 24 h, Leishmania switched from being an inhibitor to an overall inducer of autophagy. These findings of a dynamic, biphasic response were based on the accumulation of lipidated light chain 3 (LC3), an autophagosome marker, by Western blotting and confocal fluorescence microscopy. We also present evidence that Leishmania induces delayed host cell autophagy via a mechanism independent of reduced activity of the mechanistic target of rapamycin (mTOR). Notably, Leishmania actively inhibited mTOR-regulated autophagy even at later stages of infection, whereas there was a clear induction of autophagy via some other mechanism. In this context, we examined host inositol monophosphatase (IMPase), reduced levels of which have been implicated in mTOR-independent autophagy, and we found that IMPase activity is significantly decreased in infected cells. These findings indicate that Leishmania uses an alternative pathway to mTOR to induce autophagy in host macrophages. Finally, RNAi-mediated down-regulation of host autophagy protein 5 (ATG5) or autophagy protein 9A (ATG9A) decreased parasite loads, demonstrating that autophagy is essential for Leishmania survival. We conclude that Leishmania uses an alternative pathway to induce host autophagy while simultaneously inhibiting mTOR-regulated autophagy to fine-tune the timing and magnitude of this process and to optimize parasite survival.

Proflavin is one of the novel acridine derivatives that possess various pharmacological effects. Although numerous studies have been performed to investigate proflavin, its effects have not been investigated on the human osteosarcoma MG63 cell line. The core aim of the present study was to test the effects of proflavin on the viability of MG63 cells and the induction of apoptosis and autophagy in MG63 cells. The induction of apoptosis was examined by measuring the changes in the expression of the B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein mRNA and proteins. Apoptotic cell death was identified by the proteolytic cleavage of poly (adenosine diphosphate-ribose) polymerase and caspase-3 and caspase-9. In addition, the autophagic effects of proflavin were examined by the quantitation of the mRNA expression of autophagy protein 5 and Beclin 1, in addition to the identification of the accumulation of microtubule-associated protein 1 light chain 3-II. The present results revealed that proflavin inhibited the proliferation of MG63 cells in a dose-dependent manner. Proflavin-induced cell death was attributed to apoptosis and autophagy. Overall, the present results indicated that the antiseptic agent proflavin exerts anticancer potential through the synergistic activity of apoptosis and autophagy.

Chemotherapy-induced autophagy activation often contributes to cancer resistance. MiRNA-30a (miR-30a) is a potent inhibitor of autophagy by downregulating Beclin-1. In this study, we characterized the role of miR-30a in sorafenib-induced activity in renal cell carcinoma (RCC) cells. We found that expression of miR-30a was significantly downregulated in several human RCC tissues and in RCC cell lines. Accordingly, its targeted gene Beclin-1 was upregulated. Sorafenib activated autophagy in RCC cells (786-0 and A489 lines), evidenced by p62 degradation, Beclin-1/autophagy protein 5 (ATG-5) upregulation and light chain (LC)3B-I/-II conversion. Exogenously expressing miR-30a in 786-0 or A489 cells inhibited Beclin-1 expression and enhanced sorafenib-induced cytotoxicity. In contrast, knockdown of miR-30a by introducing antagomiR-30a increased Beclin-1 expression, and inhibited sorafenib-induced cytotoxicity against RCC cells. Autophagy inhibitors, including chloroquine, 3-methyaldenine or Bafliomycin A1, enhanced sorafenib activity, causing substantial cell apoptosis. Meanwhile, knockdown of Beclin-1 or ATG-5 by targeted siRNAs also increased sorafenib-induced cytotoxicity in above RCC cells. These findings indicate that dysregulation of miR-30a in RCC may interfere with the effectiveness of sorafenib-mediated apoptosis by an autophagy-dependent pathway, thus representing a novel potential therapeutic target for RCC.

This study investigated the relevance between pulp vitality and autophagy in aged human dental pulp cells (HDPCs) and whether peroxisome proliferator-activated receptor gamma (PPARγ) affects autophagy regulation for homeostasis in the aging progress. In vivo experiments were used in human and Sprague-Dawley rat teeth obtained from young and adult individuals. Aging- and autophagy-related molecules were determined by immunohistochemistry and hematoxylin and eosin staining. HDPCs were serially subcultured until spontaneously arrested for in vitro aging, and the replication deficiency adenovirus was introduced for PPARγ overexpression. Subsequently, the effect of PPARγ on regulation of autophagy molecules, mitochondria activity, and cell viability was assessed using Western blotting, confocal microscopy, and the MTT assay, respectively. In adult pulp tissue, autophagy molecules (autophagy protein 5, microtubule-associated protein 1A/1B light chain, and Beclin-1) were increased, but aging-related (PPARγ and heme oxygenase 1 [HO-1]) and dentinogenesis (dentin sialophosphoprotein and dentin matrix acidic phosphoprotein) molecules were decreased. In aged HDPCs, autophagy and intercellular adhesion molecule 1 and vascular cell adhesion molecule 1 were increased, while PPARγ and HO-1 were decreased. Under stimulation with lipopolysaccharide, autophagy- and aging-related molecules were differentially expressed between young and aged cells. PPARγ induced HO-1 and autophagy molecules but reduced inflammatory molecules in aged cells. In addition, PPARγ activated strong mitochondrial activity and cell viability in aging cells. Inhibition of HO-1 by tin protoporphyrin IX exacerbated autophagy and mitochondrial activity as well as cell viability in young cells. This study indicates that PPARγ maintains pulp homeostasis through the regulation of autophagy molecules during the life span of HDPCs.

Background Increasing resistance to cisplatin as well as the severity of the adverse effects limit the use of this drug, particularly at high doses. Evidence has implicated the importance of autophagy in cancer resistance as well as the fact that various chemotherapy agents induce autophagy in cancer cells. We therefore aimed to first assess the role of autophagy in cisplatin treatment and second to assess whether a nontoxic concentration of cisplatin, together with autophagy inhibition, is able to maintain its cancer-specific cytotoxic action. Methods Three human cervical cell lines were used: a noncancerous ectocervical epithelial cell line (Ect1/E6E7) and 2 cancerous cervical cell lines (HeLa and CaSki). Autophagy was monitored through the presence of the classical protein markers LC-3 II and p62 under basal and treatment conditions, and inhibited using bafilomycin and autophagy protein 5 (ATG5) siRNA under treatment conditions. Cell death was analyzed through examination of the apoptotic markers PARP and caspase-3 through Western blotting, as well as the Caspase-Glo assay to confirm caspase-3/7 activity. Cervical biopsies were analyzed for the presence of LC-3 using Western blotting and immunofluorescence to determine if a correlation between autophagic levels and the progression of the disease exists. Results Cervical cancer cells exhibit increased basal autophagic levels in comparison to the noncancerous counterparts. Cisplatin treatment enhanced autophagic activity in all 3 cell lines. Inhibition of this autophagic response together with cisplatin treatment leads to significant increases in cancer cell death. Expression profiles of LC-3 in normal, premalignant (low-grade and high-grade squamous intraepithelial lesion), and cancerous cervical tissue revealed that autophagy is significantly up-regulated in HSILs and carcinoma cervical tissue, which emphasized the role of autophagy in the progression of the disease. Conclusions The inhibition of autophagy improves the cytotoxicity of a nontoxic concentration of cisplatin and provides a promising new avenue for the future treatment of cervical cancer.

The aim of the present study was to investigate the effect of glucocorticoids in osteoblasts and to examine the role of β‑ecdysterone in the pathogenesis of glucocorticoid‑induced osteoporosis. Osteoblasts were induced from bone marrow mesenchymal stem cells, which were isolated from C57BL/6 mice. Cell viability and apoptosis of osteoblasts were measured by Cell Counting Kit‑8 and flow cytometry analysis, respectively. The expression of related genes and proteins was measured by reverse transcription quantitative polymerase chain reaction and western blot analysis respectively. Dose‑dependent decreases in the cell proliferation and differentiation were observed in dexamethasone (Dex)‑treated osteoblasts, evidenced by downregulation in the activity of alkaline phosphatasedecreased expression levels of Runt‑related transcription factor 2 and osteocalcin, and upregulated expression of RANK ligand. Dex also induced apoptosis and inhibited autophagy of osteoblasts, evidenced by upregulated B‑cell lymphoma 2 (Bcl‑2)‑associated X protein/Bcl‑2 ratio and the activation of mammalian target of rapamycin (mTOR), and decreased expression levels of Beclin‑1, autophagy protein 5 and microtubule‑associated protein 1 light chain 3 II. The effects on cell proliferation, apoptosis and autophagy induced by Dex were reversed by β‑ecdysterone in a dose‑dependent manner. Therefore, β‑ecdysterone may be a promising candidate drug for the treatment of osteoporosis through inducing osteoblast autophagic activity by inactivating mTOR.

While environmental exposures are not the single cause of Parkinson’s disease (PD), their interaction with genetic alterations is thought to contribute to neuronal dopaminergic degeneration. However, the mechanisms involved in dopaminergic cell death induced by gene-environment interactions remain unclear. In this work, we have revealed for the first time the role of central carbon metabolism and metabolic dysfunction in dopaminergic cell death induced by paraquat (PQ)-α-synuclein interaction. The toxicity of PQ in dopaminergic N27 cells was significantly reduced by glucose deprivation, inhibition of hexokinase with 2-deoxy-D-glucose (2-DG), or equimolar substitution of glucose with galactose, which evidenced the contribution of glucose metabolism to PQ-induced cell death. PQ also stimulated an increase in glucose uptake, and the translocation of glucose transporter type 4 (GLUT4) and Na+-glucose transporters isoform 1 (SGLT1) proteins to the plasma membrane, but only inhibition of GLUT-like transport with STF-31 or ascorbic acid reduced PQ-induced cell death. Importantly, while autophagy protein 5 (ATG5)/unc-51 like autophagy activating kinase 1 (ULK1)-dependent autophagy protected against PQ toxicity, the inhibitory effect of glucose deprivation on cell death progression was largely independent of autophagy or mammalian target of rapamycin (mTOR) signaling. PQ selectively induced metabolomic alterations and adenosine monophosphate-activated protein kinase (AMPK) activation in the midbrain and striatum of mice chronically treated with PQ. Inhibition of AMPK signaling led to metabolic dysfunction and an enhanced sensitivity of dopaminergic cells to PQ. In addition, activation of AMPK by PQ was prevented by inhibition of the inducible nitric oxide syntase (iNOS) with 1400W, but PQ had no effect on iNOS levels. Overexpression of wild type or A53T mutant α-synuclein stimulated glucose uptake and PQ toxicity, and this toxic synergism was reduced by inhibition of glucose metabolism/transport and the pentose phosphate pathway (6-aminonicotinamide). These results demonstrate that glucose metabolism and AMPK regulate dopaminergic cell death induced by gene (α-synuclein)-environment (PQ) interactions.

One of the widely accepted hypotheses of Hirschsprung's disease (HD) is that the absence of ganglion cells in the distal part of the intestine is caused by the death of enteric neural crest-derived cells following migration. Although a caspase-dependent pathway has not yet been detected in the HD bowel, it is unclear whether a caspase-independent pathway contributes toward aganglionosis. In the current study, we observed highly condensed marginal heterochromatin in nuclei only in the transitional segment using electron microscopy and a high proportion of TUNEL-positive cells were observed in the transitional segment. Activation of caspase was not observed in any segments of the HD bowel upon characterization of the apoptotic pathway. Rather, real-time PCR results showed that apoptosis-inducing factor (AIF) and calpain-1 mRNAs were highly expressed in the transitional segment, whereas autophagy protein 5 (Atg5) was highly expressed in the narrow segment. Western blot results were consistent with mRNA levels, with increased AIF, calpain-1, and Atg5 expressions in the transitional segment compared with the dilated segment. Furthermore, correlation analysis indicated an inverse correlation between calpain-1 and Atg5 mRNA levels in both the narrow segment and the transitional segment. These results indicated that apoptosis occurs in the HD bowel. The detection of related genes indicates that the AIF-mediated apoptotic pathway may be responsible for the absence of ganglion cells in HD and calpain-1 may act as the regulatory switch between autophagy and apoptosis.

Background Autophagy is a major intracellular degradation and recycling process that maintains cellular homeostasis, which is involved in structural and functional abnormalities of pulmonary vasculature in hypoxic pulmonary arterial hypertension (HPAH). Cyclophilin A (CyPA) is a secreted, oxidative stress-induced factor. Its role in inducing autophagy and augmenting endothelial cell dysfunction has never been explored. Methods Lungs from rats exposed to chronic hypoxia were examined for autophagy with electron microscopy, western blotting, and fluorescence microscopy. Results Activated autophagy was seen in the endothelium of the pulmonary artery from experimental rat models of HPAH and cultured bovine pulmonary arterial endothelial cells under hypoxia. Inhibiting autophagy attenuated the pathological progression of HPAH and repressed endothelial cell migration and angiogenesis. We also showed that CyPA was upregulated and acetylated under hypoxia and led to the abnormal occurrence of autophagy through its interaction with autophagy protein 5 and autophagy protein 7. Moreover, acetylated CyPA was essential for the excessive proliferation, migration, and tube formation networks of pulmonary arterial endothelial cells. Conclusion Our results indicate the crucial role of acetylated CyPA in the abnormal occurrence of autophagy and subsequent pulmonary vascular angiogenesis.

The aim of this study was to investigate the effects of acriflavine on viability and induction of apoptosis and autophagy in human osteosarcoma cell lines MG63. Inhibition of cell proliferation by acriflavine was determined using MTT assay. Induction of apoptosis was examined by measuring the changes in expression of Bcl-2 and Bax in messenger RNA (mRNA) and protein levels. Identification of the proteolytic cleavage of poly (ADP)-ribose polymerase (PARP) and caspase-3 and caspase-9 was carried out to study apoptotic cell death. Autophagic effects were examined by quantitation of mRNA expression of autophagy protein 5 (Atg5) and Beclin1 and identifying accumulation of microtubule-associated protein 1 light chain 3 (LC3)-II. The results showed acriflavine inhibited cell proliferation of osteosarcoma cells in dose-dependent fashion. Acriflavine-induced cell death was attributed to both apoptosis and autophagy. Moreover, it was associated with changes in the levels of Bcl-2 and Bax in the osteosarcoma cells. The antiseptic agent, acriflavine, has anticancer potential through synergistic activity of apoptosis and autophagy.

Osteoporosis is an aging process of skeletal tissues with characteristics of reductions in bone mass and microarchitectural deterioration of bone tissue. The present study aimed to investigate the effects of glucocorticoid‑induced osteoporosis on osteoblasts and to examine the roles of β‑ecdysterone (β‑Ecd) involved. In the present study, an in vivo model of osteoporosis was established through the subcutaneous implantation of prednisolone (PRED) into Sprague‑Dawley rats, with or without a subcutaneous injection of β‑Ecd (5 or 10 mg/kg body weight). Expression of Beclin‑1 and microtubule‑associated protein 1A/1B‑light chain 3I/II and apoptosis in lumbar vertebrae tissues was measured by immunofluorescence and TUNEL assays, respectively. Serum concentration of calcium and phosphorus, and the activity of tartrate‑resistant acid phosphatase (TRAP) and alkaline phosphatase (ALP) were measured by biochemical assay. Reverse transcription‑quantitative polymerase chain reaction and western blotting was used for detect the expression of related genes and proteins. PRED treatment inhibited bone formation by decreasing bone mineral density, and suppressing the expression of Runt‑related transcription factor 2 and bone morphogenetic protein 2, while enhancing the activity of alkaline phosphatase, upregulating the expression of receptor activator of nuclear factor-κB ligand, and increasing the serum content of calcium, phosphorus and tartrate‑resistant acid phosphatase in rats. Additionally, PRED was revealed to inhibit autophagy through the downregulation of Beclin‑1, autophagy protein 5 and microtubule‑associated protein 1A/1B‑light chain 3I/II expression, whereas it induced the apoptosis, through the activation of caspase‑3 and the suppression of apoptosis regulator BCL2 expression. Notably, the PRED‑induced alterations in bone formation, autophagy and apoptosis were revealed to be attenuated by β‑Ecd administration. In conclusion, the findings of the present study suggested that β‑Ecd may be a promising candidate for the development of therapeutic strategies for the treatment of osteoporosis, through the induction of autophagy and the inhibition of apoptosis in vivo.

„„Candidatus Phytoplasma aurantifolia‟‟ is the causative agent of witches‟ broom disease in the Mexican lime tree (Citrus aurantifolia L.), and is responsible for major tree losses in Southern Iran and Oman. The pathogen is strictly biotrophic, and thus is completely dependent on living host cells for its survival. The molecular basis of compatibility and disease development in this system is poorly understood. Transcryptomic analysis of the susceptible lime cultivar at the representative symptoms stage showed a number of candidate genes that might be involved in the interaction of Mexican lime trees with “Ca P. aurantifolia”. These included the genes for modifier of snc1, autophagy protein 5, formin, importin В3, transducin, L-asparaginase, glycerophosphoryl diester phosphodiesterase, and RNA polymerase b. In contrast, genes involved in basal metabolism like a proline-rich protein, ubiquitin-protein ligase, phosphatidyl glycerol specific phospholipase C-like, and serine/threonine-protein kinase. Proteomic analysis results reveal proteins that were involved in oxidative stress defense, photosynthesis, metabolism, and the stress response, regulate in infected trees. For the moment these results should help to identify genes that could be targeted to increase plant resistance and inhibit the growth and reproduction of the pathogen.

Vici syndrome is a recessively inherited multisystem disorder characterized by callosal agenesis, cataracts, cardiomyopathy, combined immunodeficiency and hypopigmentation. To investigate the molecular basis of Vici syndrome, we carried out exome and Sanger sequence analysis in a cohort of 18 affected individuals. We identified recessive mutations in EPG5 (previously KIAA1632), indicating a causative role in Vici syndrome. EPG5 is the human homolog of the metazoan-specific autophagy gene epg-5, encoding a key autophagy regulator (ectopic P-granules autophagy protein 5) implicated in the formation of autolysosomes. Further studies showed a severe block in autophagosomal clearance in muscle and fibroblasts from individuals with mutant EPG5, resulting in the accumulation of autophagic cargo in autophagosomes. These findings position Vici syndrome as a paradigm of human multisystem disorders associated with defective autophagy and suggest a fundamental role of the autophagy pathway in the immune system and the anatomical and functional formation of organs such as the brain and heart.

Sir, We read with interest the recent letter by Kane and colleagues (2016) reporting on ‘Aberrant splicing induced by the most common EPG5 mutation in an individual with Vici Syndrome’. Vici syndrome (OMIM 242840), originally described by Dionisi-Vici and colleagues in 1988 (Vici et al. , 1988), is one of the most extensive inherited human multisystem disorders identified to date, characterized by global developmental delay, failure to thrive, postnatally acquired microcephaly, callosal agenesis, cataracts, often fatal cardiomyopathy, combined immunodeficiency and generalized hypopigmentation (Cullup et al. , 2013; Byrne et al. , 2016 a , b ). Although the clinical phenotype is largely homogeneous, some features (in particular cardiac and immunological involvement) show considerable variability regarding onset and severity, with important effects on overall morbidity and life expectancy. EPG5 encodes a key component of the autophagy pathway in multicellular organisms (Tian et al. , 2010), ectopic P-granules autophagy protein 5 (EPG5), with a crucial role in autophagosome-lysosome fusion (Cullup et al. , 2013) and possibly other intracellular fusion events. Direct proof of the detrimental effects of EPG5 deficiency on the neuronal level has been recently provided in a Drosophila model (Byrne …

Purpose: The tumor suppressor protein p53 may have regulatory roles in exercise response-adaptation processes such as mitochondrial biogenesis and autophagy, although its cellular location largely governs its biological role. We investigated the subcellular localization of p53 and selected signaling targets in human skeletal muscle following a single bout of endurance exercise.\ud Methods: Sixteen, untrained individuals were pair-matched for aerobic capacity (VO2peak) and allocated to either an exercise (EX, n = 8) or control (CON, n = 8) group. After a resting muscle biopsy, EX performed 60 min continuous cycling at ~70% of VO2peak during which time CON subjects rested. A further biopsy was obtained from both groups 3 h post-exercise (EX) or 4 h after the first biopsy (CON).\ud Results: Nuclear p53 increased after 3 h recovery with EX only (~48%, p < 0.05) but was unchanged in the mitochondrial or cytoplasmic fractions in either group. Autophagy protein 5 (Atg-5) decreased in the mitochondrial protein fraction 3 h post-EX (~69%, P < 0.05) but remained unchanged in CON. There was an increase in cytoplasmic levels of the mitophagy marker PINK1 following 3 h of rest in CON only (~23%, P < 0.05). There were no changes in mitochondrial, nuclear, or cytoplasmic levels of PGC-1α post-exercise in either group.\ud Conclusions: The selective increase in nuclear p53 abundance following endurance exercise suggests a potential pro-autophagy response to remove damaged proteins and organelles prior to initiating mitochondrial biogenesis and remodeling responses in untrained individuals.

Aims/Introduction: Islets in type 2 diabetes are characterized by depos ition of islet amyloid polypeptide (IAPP) as well as b-celldysfunction. The unique amyloidogenic character of human (h)IAPP i s associated with cytotoxicity. Autophagy is a ubiquitous system ofcellular recycling that contributesto cellsurvi val. Thus, we examined whetherautophagycould amelioratehIAPP-associated cytotoxicity.Materials and Methods: First, we used a COS-1 cell model, lacking endogenous IAPP that might affect cytotoxicity related toexogenous hIAPP. Next, we used the mouse b-cell line, MIN-6 cells. Both cells were transfected with hIAPP or rat (r)IAPP expressionconstructs, or transfected with bicistronic vectors expressing green fluorescent protein (GFP) and either hIAPP or rIAPP for flowcytometry analysis. Cell viability and apoptosis markers were stud ied in relation to chemical or genetic modulation of autophagy.Results: The viability of cells expressing hIAPP was significantly decreased as compared with those expressing rIAPP and the cleav-age of pro-caspase-3 was elevated in hIAPP-transfected cells. The formation of autoph agosomes and the conversion of microtubule-associated protein light chain 3B I to II were elevated in hIAPP-expre ssing cells. The viability of hIAPP-expressing cells was increasedafter treatment with rapamycin, an inducer of autophagy, and decr eased after treatment with 3-met hyladenine, an inhibitor of auto-phagy. In MIN-6 cells, annexin positive cells were increased by 3- methyladenine and decreased by rapamycin using flow cytometry.Knocking down of the autophagy protein 5 gene de creased hIAPP-transfected cell viability.Conclusions: Autophagy is co-localized with hIAPP expression and it plays a protective role in hIAPP-associated apoptosis.(J Diabetes Invest, doi: 10.1111/j.2040-1124.2010.00065.x, 2010)KEY WORDS: Autophagy, Islet amyloid polypeptide, Type 2 diabetesINTRODUCTIONThe islets of patients with type 2 diabetes (T2D) are character-ized by the deposition of islet amyloid

Autophagy, or cellular self-digestion, is a cellular pathway involved in protein and organelle degradation, with an astonishing number of connections to human disease and physiology. For example, autophagic dysfunction is associated with cancer, neurodegeneration, microbial infection and ageing. Paradoxically, although autophagy is primarily a protective process for the cell, it can also play a role in cell death. Understanding autophagy may ultimately allow scientists and clinicians to harness this process for the purpose of improving human health.

Cell migration is a process crucial for a variety of biological events, such as morphogenesis and wound healing. Several reports have described the possible regulation of cell migration by autophagy; however, this remains controversial. We here demonstrate that mouse embryonic fibroblasts (MEFs) lacking autophagy protein 5 (Atg5), an essential molecule of autophagy, moved faster than wild-type (WT) MEFs. Similar results were obtained for MEFs lacking Atg7 and unc-51-like kinase 1 (Ulk1), which are molecules required for autophagy. This phenotype was also observed in Atg7-deficient macrophages. WT MEFs moved by mesenchymal-type migration, whereas Atg5 knockout (KO) MEFs moved by amoeba-like migration. This difference was thought to be mediated by the level of RhoA activity, because Atg5 KO MEFs had higher RhoA activity, and treatment with a RhoA inhibitor altered Atg5 KO MEF migration from the amoeba type to the mesenchymal type. Autophagic regulation of RhoA activity was dependent on GEF-H1, a member of the RhoA family of guanine nucleotide exchange factors. In WT MEFs, GEF-H1 directly bound to p62 and was degraded by autophagy, resulting in low RhoA activity. In contrast, the loss of autophagy increased GEF-H1 levels and thereby activated RhoA, which caused cells to move by amoeba-like migration. This amoeba-like migration was cancelled by the silencing of GEF-H1. These results indicate that autophagy plays a role in the regulation of migration by degrading GEF-H1.

Human bocavirus (HBoV) is classified in the Bocavirus genus within the Parvoviridae family, first identified from children with respiratory diseases. Previous studies have investigated the stimulating effect of HBoV on cell apoptosis and autophagy. In the present study, human bronchial epithelial cells (HBECs) were utilized to examine the mechanism of HBoV recombination expressing vector (pWHL-1) on the promotion of cell apoptosis and autophagy. The results from the present study indicated that pWHL-1 inhibited the proliferation of HBECs in a time-dependent manner. Additionally, pWHL-1induced apoptosis, as substantiated by an increased apoptotic rate and presence of autophagosomes. Following pWHL-1 transfection, proliferating cell nuclear antigen, caspase-3 and B cell lymphoma 2 (Bcl-2) protein expression levels were decreased, with the exception of Bcl-2 associated × (Bax) protein, which increased. mRNA and protein expression levels of microtubule-associated protein 1A/1B-light chain 3 (LC3) II and autophagy protein 5 were increased in pWHL-1-transfected HBECs, whereas, the mRNA and protein levels of LC3I and sequestosome 1 were decreased. Notably, pWHL-1 also enhanced the activation of p53 and inhibited AKT activation in HBECs. Results from the present study suggest that pWHL-1 induces apoptosis and autophagy, thus providing a novel insight into the effect of HBoV and its uses in respiratory diseases.

Deep venous thrombosis (DVT) is one of the most common peripheral vascular diseases. The roles of bone marrow-derived endothelial progenitor cells (EPCs) on the recanalization of venous thrombosis has been suggested recently, while the underlying mechanisms are not completely understood. Our objective was to investigate the functions of autophagy protein 5 (ATG5) in rat EPCs and its potential application in DVT. We have found that silencing of ATG5 or pharmacological suppression of ATG5 in rat EPCs reduces both the migration and psudotube formation under hypoxia in vitro. In line, overexpression of ATG5 significantly enhances the EPCs migration and psudotube formation capabilities. More importantly, injection of EPCs that stably express ATG5 increases EPC homing to the ischemic site and promotes thrombus recanalization in a rat DVT model in vivo. Mechanistically, we have shown that ATG5 overexpression enhances psudotube formation via the activation of AKT. These findings suggest that ATG5-AKT signaling plays an essential role in EPC migration and psudotube formation. Regulation of ATG5-AKT signaling may provide a potential novel therapy for DVT.

Intracytoplasmic inclusions of protein aggregates in dopaminergic cells (Lewy bodies) are the pathological hallmark of Parkinson's disease (PD). Ubiquitin (Ub), alpha (α)-synuclein, p62/sequestosome 1, and oxidized proteins are the major components of Lewy bodies. However, the mechanisms involved in the impairment of misfolded/oxidized protein degradation pathways in PD are still unclear. PD is linked to mitochondrial dysfunction and environmental pesticide exposure. In this work, we evaluated the effects of the pesticide paraquat (PQ) and the mitochondrial toxin 1-methyl-4-phenylpyridinium (MPP(+)) on Ub-dependent protein degradation pathways. No increase in the accumulation of Ub-bound proteins or aggregates was observed in dopaminergic cells (SK-N-SH) treated with PQ or MPP(+), or in mice chronically exposed to PQ. PQ decreased Ub protein content, but not its mRNA transcription. Protein synthesis inhibition with cycloheximide depleted Ub levels and potentiated PQ-induced cell death. The inhibition of proteasomal activity by PQ was found to be a late event in cell death progression and had neither effect on the toxicity of either MPP(+) or PQ, nor on the accumulation of oxidized sulfenylated, sulfonylated (DJ-1/PARK7 and peroxiredoxins), and carbonylated proteins induced by PQ. PQ- and MPP(+)-induced Ub protein depletion prompted the dimerization/inactivation of the Ub-binding protein p62 that regulates the clearance of ubiquitinated proteins by autophagy. We confirmed that PQ and MPP(+) impaired autophagy flux and that the blockage of autophagy by the overexpression of a dominant-negative form of the autophagy protein 5 (dnAtg5) stimulated their toxicity, but there was no additional effect upon inhibition of the proteasome. PQ induced an increase in the accumulation of α-synuclein in dopaminergic cells and membrane-associated foci in yeast cells. Our results demonstrate that the inhibition of protein ubiquitination by PQ and MPP(+) is involved in the dysfunction of Ub-dependent protein degradation pathways.

Wnt signaling is one of the core signaling pathways of cancer stem cells (CSCs). It is re-activated in CSCs and plays essential role in the survival, self-renewal and proliferation of these cells. Therefore, we aimed to evaluate the cytotoxic effects of palladium(II) complex which is formulated as [PdCl(terpy)](sac)2H(2)O and its combination with niclosamide which is an inhibitor of Wnt signaling pathway associated with breast cancer stem cells. Characteristic cell surface markers (CD44(+)/CD24(-)) were determined by flow cytometry in CSCs. ATP viability assay was used to determine the cytotoxic activity. The mode of cell death was evaluated morphologically using fluorescence microscopy and biochemically using M30 ELISA assay as well as performing qPCR. Our study demonstrated that the combination of niclosamide (1.5 mu M) and Pd(II) complex (12.5, 25 and 50 mu M) at 48 h has enhanced cytotoxic activity resulted from the induction of apoptosis (indicated by the presence of pyknotic nuclei, increments in M30 and over expression of proapoptotic genes of TNFRSF10A and FAS). Importantly, the addition of niclosamide resulted in the suppression of autophagy (proved by the decrease in ATG5 gene levels) that might have contributed to the enhanced cytotoxicity. In conclusion, the application of this combination may be regarded as a novel and effective approach for the treatment of breast cancer due to its promising cytotoxic effect on cancer stem cells that cause recurrence of the disease. (C) 2015 Elsevier Ltd. All rights reserved.

Cervical cancer is one of the most common gynecological cancers in association with high mortality and morbidity. The present study was aimed to investigate the in vitro effects of zoledronic acid (ZA) on viability and induction of apoptosis and autophagy as well as inflammatory effects in three human cervical cancer cell lines (HeLa, SiHa, and CaSki). Cell viability was measured by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay. Induction of apoptosis was determined by quantitation of expression level of B cell lymphoma 2 (Bcl-2) and Bax messenger RNA (mRNA) and identification of the proteolytic cleavage of poly (ADP)-ribose polymerase (PARP) and caspase-3. Autophagic effects were examined by quantitation of mRNA expression of autophagy protein 5 (ATG5) and beclin1 and identifying accumulation of microtubule-associated protein 1 light chain 3 (LC3)-II. Inflammatory effect was determined by measuring expression and production of IL-6 and cyclooxygenase-2 (Cox-2). The results showed ZA significantly inhibited cell viability of cervical cancer cells. ZA-induced cell death displayed features characteristic to both apoptosis and autophagy and was associated with different changes in the levels of Bcl-2 and Bax in the various cervical cancer lines. Expression of metastatic cytokines, IL-6 and Cox-2, was upregulated in the presence of ZA at low concentration. Our data revealed that ZA inhibits cervical cancer cells through the synergistic effect of apoptosis induction and autophagy activation.

The Sigma1 receptor (Sigma1) is an endoplasmic reticulum (ER) integral membrane protein that is highly expressed in a number of cancer cell lines. Small molecule compounds targeting Sigma1 (Sigma1 ligands) inhibit cancer cell proliferation and induce apoptotic cell death in vitro and inhibit tumor growth in xenograft experiments. However, the cellular pathways activated by Sigma1 protein-ligand interaction are not well defined. Here, we find that treatment with some Sigma1 ligands induces ER stress and activates the unfolded protein response (UPR) in a dose- and time-responsive manner in a range of adenocarcinoma cell lines. Autophagy is engaged after extended treatment with Sigma1 ligands, which suggests that protracted UPR results in autophagy as a secondary response. Inhibition of UPR by RNAi-mediated knockdown of inositol-requiring enzyme 1α and activating transcription factor 4 abrogates autophagosome formation, as does knockdown of essential autophagy gene products Beclin1 and autophagy protein 5. Knockdown of Sigma1 also suppresses IPAG [1-(4-iodophenyl)-3-(2-adamantyl) guanidine] induced UPR marker and autophagosome levels, indicating that this response is indeed Sigma1-mediated. We find that UPR activation precedes autophagosome formation and autophagy precedes apoptosis in Sigma1 ligand-treated cells. These processes are reversible, and washout of IPAG before cell death results in a return of autophagosomes and UPR markers toward basal levels. However, inhibition of Sigma1 ligand-induced UPR or autophagy accelerates apoptotic cell death. Together, these data suggest that UPR and autophagy are engaged as primary and secondary cytoprotective responses, respectively, to Sigma1 ligand-induced disruption of cancer cell protein homeostasis.

Controversial reports on the role of autophagy as a survival or cell death mechanism in dopaminergic cell death induced by parkinsonian toxins exist. We investigated the alterations in autophagic flux and the role of autophagy protein 5 (Atg5)-dependent autophagy in dopaminergic cell death induced by parkinsonian toxins. Dopaminergic cell death induced by the mitochondrial complex I inhibitors 1-methyl-4-phenylpyridinium (MPP+) and rotenone, the pesticide paraquat, and the dopamine analog 6-hydroxydopamine (6-OHDA) was paralleled by increased autophagosome accumulation. However, when compared with basal autophagy levels using chloroquine, autophagosome accumulation was a result of impaired autophagic flux. Only 6-OHDA induced an increase in autophagosome formation. Overexpression of a dominant negative form of Atg5 increased paraquat- and MPP+-induced cell death. Stimulation of mammalian target of rapamycin (mTOR)-dependent signaling protected against cell death induced by paraquat, whereas MPP+-induced toxicity was enhanced by wortmannin, a phosphoinositide 3-kinase class III inhibitor, rapamycin, and trehalose, an mTOR-independent autophagy activator. Modulation of autophagy by either pharmacological or genetic approaches had no effect on rotenone or 6-OHDA toxicity. Cell death induced by parkinsonian neurotoxins was inhibited by the pan caspase inhibitor (Z-VAD), but only caspase-3 inhibition was able to decrease MPP+-induced cell death. Finally, inhibition of the lysosomal hydrolases, cathepsins, increased the toxicity by paraquat and MPP+, supporting a protective role of Atg5-dependent autophagy and lysosomes degradation pathways on dopaminegic cell death. These results demonstrate that in dopaminergic cells, Atg5-dependent autophagy acts as a protective mechanism during apoptotic cell death induced by paraquat and MPP+ but not during rotenone or 6-OHDA toxicity.

Autophagy is a dynamic and highly regulated process of self-digestion responsible for cell survival and reaction to oxidative stress. As oxidative stress is increased in uremia and is associated with vascular calcification, we studied the role of autophagy in vascular calcification induced by phosphate. In an in vitro phosphate-induced calcification model of vascular smooth muscle cells (VSMCs) and in an in vivo model of chronic renal failure, autophagy was inhibited by the superoxide dismutase mimic MnTMPyP, superoxide dismutase-2 overexpression, and by knockdown of the sodium-dependent phosphate cotransporter Pit1. Although phosphate-induced VSMC apoptosis was reduced by an inhibitor of autophagy (3-methyladenine) and knockdown of autophagy protein 5, calcium deposition in VSMCs was increased during inhibition of autophagy, even with the apoptosis inhibitor Z-VAD-FMK. An inducer of autophagy, valproic acid, decreased calcification. Furthermore, 3-methyladenine significantly promoted phosphate-induced matrix vesicle release with increased alkaline phosphatase activity. Thus, autophagy may be an endogenous protective mechanism counteracting phosphate-induced vascular calcification by reducing matrix vesicle release. Therapeutic agents influencing the autophagic response may be of benefit to treat aging or disease-related vascular calcification and osteoporosis.

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.

The transcription factor E2F-1 plays a crucial role in the control of cell proliferation. E2F-1 has tumor suppressive properties by inducing apoptosis and autophagy. In this study, E2F-1 and its truncated form (E2Ftr), lacking the transactivation domain (TAD), were compared for their ability to induce autophagy. In Gaussia luciferase-based assays, both E2F-1 and E2Ftr induced the proteolytic cleavage of the autophagic marker LC3. In addition, LC3 and autophagy protein 5 (Atg5) were upregulated by E2F-1 and E2Ftr. Likewise, both E2F proteins induced a punctate pattern of GFP-tagged LC3, indicating autophagosome formation. The presence of double-membrane autophagic vesicles induced by E2F-1 and E2Ftr was confirmed by transmission electron microscopy (TEM). The application of z-VAD-fmk, a caspase inhibitor, partially blocked both E2F-1 and E2Ftr-mediated cytotoxicity. Moreover, Atg5 (-/-) cells were more resistant to the E2F-1 or E2Ftr-induced cell killing effect than Atg5 wt cells. The TAD of E2F-1 is not essential for induction of autophagy; apoptosis and autophagy cooperate for an efficient cancer cell killing effect induced by E2F-1 or E2Ftr. E2Ftr-induced autophagy is a promising approach to destroy tumors that are resistant to conventional treatments.

3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitors (statins) are cholesterol-lowering drugs that exert other cellular effects and underlie their beneficial health effects, including those associated with myocardial remodeling. We recently demonstrated that statins induces apoptosis and autophagy in human lung mesenchymal cells. Here, we extend our knowledge showing that statins simultaneously induces activation of the apoptosis, autophagy and the unfolded protein response (UPR) in primary human atrial fibroblasts (hATF). Thus we tested the degree to which coordination exists between signaling from mitochondria, endoplasmic reticulum and lysosomes during response to simvastatin exposure. Pharmacologic blockade of the activation of ER-dependent cysteine-dependent aspartate-directed protease (caspase)-4 and lysosomal cathepsin-B and -L significantly decreased simvastatin-induced cell death. Simvastatin altered total abundance and the mitochondrial fraction of proapoptotic and antiapoptotic proteins, while c-Jun N-terminal kinase/stress-activated protein kinase mediated effects on B-cell lymphoma 2 expression. Chemical inhibition of autophagy flux with bafilomycin-A1 augmented simvastatin-induced caspase activation, UPR and cell death. In mouse embryonic fibroblasts that are deficient in autophagy protein 5 and refractory to autophagy induction, caspase-7 and UPR were hyper-induced upon treatment with simvastatin. These data demonstrate that mevalonate cascade inhibition-induced death of hATF manifests from a complex mechanism involving co-regulation of apoptosis, autophagy and UPR. Furthermore, autophagy has a crucial role in determining the extent of ER stress, UPR and permissiveness of hATF to cell death induced by statins. © 2012 Macmillan Publishers Limited. All rights reserved.

Oxidative stress induces not only senescence but also autophagy in a variety of mammalian cells. However, the relationship between these two has not been well established and thus, was investigated in the present study using WI38 human diploid fibroblasts (WI38 cells) as a model system. Our results showed that exposure of WI38 cells to H2O2 induced both senescence and autophagy. Downregulation of autophagy protein 5 (Atg5) with Atg5 siRNA inhibited not only autophagy but also senescence induced by H2O2. Further studies showed that Atg5 regulates H2O2-induced senescence primarily by up-regulating the expression of p21 at the level of post-transcription. In addition, we examined the mechanisms by which H2O2 induces autophagy in WI38 cells. Our results revealed that H2O2 increases autophagy independent of the mammalian target of rapamycin (mTOR) negative feedback pathway. Instead, the induction of autophagy by H2O2 depends on the induction of intracellular production of reactive oxygen species (ROS) and activation of the p38 mitogen-activated protein kinase α (p38 MAPKα) pathway.