Effect of ginger, chamomile, and green tea extracts on prostate cancer cells.

Prostate cancer (PCa) is a prevalent form of malignancy in males and is a significant contributor to cancer-related mortality worldwide. Because of this, studying the molecular processes of PCa cell growth and death is crucial. Hence, it is imperative to conduct further research on the regulatory mechanism underlying the progression of PCa to enhance our comprehension and identify innovative therapeutic targets. The present study investigates an experimental approach that utilizes cost-effective and environmentally sustainable plant extracts sourced from Egypt, namely ginger, chamomile, and green tea, which have been solubilized in dimethyl sulfoxide (DMSO), then characterized by using different analytical means and techniques, such as HPLC and GC-MS. The present study employed MTT assay, ELISA, and qRT-PCR techniques to assess the possible impact of the investigated extracts on PCa in PC-3 cells. The findings indicate that ginger exhibited a noteworthy cytotoxic impact on PC-3. Remarkably, the treatment of PCa cells with ginger significantly increased relative lactate dehydrogenase (LDH) production compared to those treated with chamomile and green tea extracts. Autophagy may play a crucial role in the context of chemotherapy. Modifying autophagy through its induction or inhibition is a promising and innovative approach to controlcancer progression. Accordingly, it was found that ginger extract affects protein expression levels of autophagy markers LC3B, ATg12, and pro-apoptotic signaling, including the Caspase-3 signaling pathway. The ELISA findings revealed a significant rise in the average levels of IL-1ß and IL-8 after a 12-hour interval. To conclude, it can be inferred that ginger extract possesses the capability to control the production of inflammatory cytokines. Alternatively, utilizing herbal remedies containing ginger as a viable and secure means of treating PCa as an anticancer agent is possible.

Zinc Oxide Nanoparticles Trigger Autophagy in the Human Multiple Myeloma Cell Line RPMI8226: an In Vitro Study.

Multiple myeloma (MM) is a malignant clonal proliferative plasma cell tumor. Zinc oxide nanoparticles (ZnO NPs) are used for antibacterial and antitumor applications in the biomedical field. This study investigated the autophagy-induced effects of ZnO NPs on the MM cell line RPMI8226 and the underlying mechanism. After RPMI8226 cells were exposed to various concentrations of ZnO NPs, the cell survival rate, morphological changes, lactate dehydrogenase (LDH) levels, cell cycle arrest, and autophagic vacuoles were monitored. Moreover, we investigated the expression of Beclin 1 (Becn1), autophagy-related gene 5 (Atg5), and Atg12 at the mRNA and protein levels, as well as the level of light chain 3 (LC3). The results showed that ZnO NPs could effectively inhibit the proliferation and promote the death of RPMI8226 cells in vitro in a dose- and time-dependent manner. ZnO NPs increased LDH levels, enhanced monodansylcadaverine (MDC) fluorescence intensity, and induced cell cycle arrest at the G2/M phases in RPMI8226 cells. Moreover, ZnO NPs significantly increased the expression of Becn1, Atg5, and Atg12 at the mRNA and protein levels and stimulated the production of LC3. We further validated the results using the autophagy inhibitor 3-methyladenine (3­MA). Overall, we observed that ZnO NPs can trigger autophagy signaling in RPMI8226 cells, which may be a potential therapeutic approach for MM.

circ_SIRT1 upregulates ATG12 to facilitate Imatinib resistance in CML through interacting with EIF4A3.

Imatinib is the current gold standard for patients with chronic myeloid leukemia (CML). However, the primary and acquired drug resistance seriously limits the efficacy. To identify novel therapeutic target in Imatinib-resistant CML is of crucial clinical significance. CircRNAs have been demonstrated the essential regulatory roles in the progression and drug resistance of cancers. In this study, we identified a novel circRNA (circ_SIRT1), derived from the SIRT1, which is up-regulated in CML. The high expression of circ_SIRT1 is correlated with drug resistance in CML. Knockdown of circ_SIRT1 regulated K562/R cells viability, invasion and apoptosis. Besides, the inhibition of circ_SIRT1 attenuated autophagy level and reduced IC50 to Imatinib of K562/R cells. Mechanistically, circ_SIRT1 directly binds to the transcription factor Eukaryotic Translation Initiation Factor 4A3(EIF4A3) and regulated EIF4A3-mediated transcription of Autophagy Related 12 (ATG12), thereby affecting Imatinib resistance and autophagy level. Overexpression of ATG12 reversed the regulative effects induced by knockdown of circ_SIRT1. Taken together, our findings revealed circ_SIRT1 acted as a potential tumor regulator in CML and unveiled the underlying mechanism on regulating Imatinib resistance. circ_SIRT1 may serve as a novel therapeutic target and provide crucial clinical implications for Imatinib-resistant CML treatment.

miR-30a-3p Regulates Autophagy in the Involution of Mice Mammary Glands.

The mammary gland undergoes intensive remodeling during the lactation cycle, and the involution process of mammary gland contains extensive epithelial cells involved in the process of autophagy. Our studies of mice mammary glands suggest that miR-30a-3p expression was low during involution compared with its high expression in the mammary glands of lactating mice. Then, we revealed that miR-30a-3p negatively regulated autophagy by autophagy related 12 (Atg12) in mouse mammary gland epithelial cells (MMECs). Restoring ATG12, knocking down autophagy related 5 (Atg5), starvation, and Rapamycin were used to further confirm this conclusion. Overexpression of miR-30a-3p inhibited autophagy and altered mammary structure in the involution of the mammary glands of mice, which was indicative of alteration in mammary remodeling. Taken together, these results elucidated the molecular mechanisms of miR-30a-3p as a key induction mediator of autophagy by targeting Atg12 within the transition period between lactation and involution in mammary glands.

Interactome of Arabidopsis ATG5 Suggests Functions beyond Autophagy.

Autophagy is a catabolic pathway capable of degrading cellular components ranging from individual molecules to organelles. Autophagy helps cells cope with stress by removing superfluous or hazardous material. In a previous work, we demonstrated that transcriptional upregulation of two autophagy-related genes, ATG5 and ATG7, in Arabidopsis thaliana positively affected agronomically important traits: biomass, seed yield, tolerance to pathogens and oxidative stress. Although the occurrence of these traits correlated with enhanced autophagic activity, it is possible that autophagy-independent roles of ATG5 and ATG7 also contributed to the phenotypes. In this study, we employed affinity purification and LC-MS/MS to identify the interactome of wild-type ATG5 and its autophagy-inactive substitution mutant, ATG5K128R Here we present the first interactome of plant ATG5, encompassing not only known autophagy regulators but also stress-response factors, components of the ubiquitin-proteasome system, proteins involved in endomembrane trafficking, and potential partners of the nuclear fraction of ATG5. Furthermore, we discovered post-translational modifications, such as phosphorylation and acetylation present on ATG5 complex components that are likely to play regulatory functions. These results strongly indicate that plant ATG5 complex proteins have roles beyond autophagy itself, opening avenues for further investigations on the complex roles of autophagy in plant growth and stress responses.

ATG16L1 and ATG12 Gene Polymorphisms Are Involved in the Progression of Atrophic Gastritis.

Helicobacter pylori (H. pylori) infection causes a progression to atrophic gastritis and results in gastric cancer. Cytotoxin-associated gene A (CagA), a major virulence factor of H. pylori, is injected into gastric epithelial cells using the type IV secretion system. On the other hand, gastric epithelial cells degrade CagA using an autophagy system, which is strictly regulated by the autophagy-related (ATG) genes. This study aimed to identify SNPs in ATG5, ATG10, ATG12, and ATG16L1 associated with gastric mucosal atrophy (GMA). Here, two-hundred H. pylori-positive participants without gastric cancer were included. The degree of GMA was evaluated via the pepsinogen method. Twenty-five SNPs located in the four candidate genes were selected as tag SNPs. The frequency of each SNP between the GMA and the non-GMA group was evaluated. The rs6431655, rs6431659, and rs4663136 in ATG16L1 and rs26537 in ATG12 were independently associated with GMA. Of these four SNPs, the G/G genotype of rs6431659 in ATG16L1 has the highest odd ratio (Odds ratio = 3.835, 95% confidence intervals = 1.337-1.005, p = 0.008). Further functional analyses and prospective analyses with a larger sample size are required.

Progranulin regulation of autophagy contributes to its chondroprotective effect in osteoarthritis.

Progranulin (PGRN) is a multifunctional growth factor involved in many physiological processes and disease states. The apparent protective role of PGRN and the importance of chondrocyte autophagic function in the progression of osteoarthritis (OA) led us to investigate the role of PGRN in the regulation of chondrocyte autophagy. PGRN knockout chondrocytes exhibited a deficient autophagic response with limited induction following rapamycin, serum starvation, and IL-1ß-induced autophagy. PGRN-mediated anabolism and suppression of IL-1ß-induced catabolism were largely abrogated in the presence of the BafA1 autophagy inhibitor. Mechanistically, during the process of OA, PGRN and the ATG5-ATG12 conjugate form a protein complex; PGRN regulates autophagy in chondrocytes and OA through, at least partially, the interactions between PGRN and the ATG5-ATG12 conjugate. Furthermore, the ATG5-ATG12 conjugate is critical for cell proliferation and apoptosis. Knockdown or knockout of ATG5 reduces the expression of ATG5-ATG12 conjugate and inhibits the chondroprotective effect of PGRN on anabolism and catabolism. Overexpression of PGRN partially reversed this effect. In brief, the PGRN-mediated regulation of chondrocyte autophagy plays a key role in the chondroprotective role of PGRN in OA. Such studies provide new insights into the pathogenesis of OA and PGRN-associated autophagy in chondrocyte homeostasis.

TECPR1 conjugates LC3 to damaged endomembranes upon detection of sphingomyelin exposure.

Invasive bacteria enter the cytosol of host cells through initial uptake into bacteria-containing vacuoles (BCVs) and subsequent rupture of the BCV membrane, thereby exposing to the cytosol intraluminal, otherwise shielded danger signals such as glycans and sphingomyelin. The detection of glycans by galectin-8 triggers anti-bacterial autophagy, but how cells sense and respond to cytosolically exposed sphingomyelin remains unknown. Here, we identify TECPR1 (tectonin beta-propeller repeat containing 1) as a receptor for cytosolically exposed sphingomyelin, which recruits ATG5 into an E3 ligase complex that mediates lipid conjugation of LC3 independently of ATG16L1. TECPR1 binds sphingomyelin through its N-terminal DysF domain (N'DysF), a feature not shared by other mammalian DysF domains. Solving the crystal structure of N'DysF, we identified key residues required for the interaction, including a solvent-exposed tryptophan (W154) essential for binding to sphingomyelin-positive membranes and the conjugation of LC3 to lipids. Specificity of the ATG5/ATG12-E3 ligase responsible for the conjugation of LC3 is therefore conferred by interchangeable receptor subunits, that is, the canonical ATG16L1 and the sphingomyelin-specific TECPR1, in an arrangement reminiscent of certain multi-subunit ubiquitin E3 ligases.

The Ubiquitin-like Proteins of Saccharomyces cerevisiae.

In this review, we present a comprehensive list of the ubiquitin-like modifiers (Ubls) of Saccharomyces cerevisiae, a common model organism used to study fundamental cellular processes that are conserved in complex multicellular organisms, such as humans. Ubls are a family of proteins that share structural relationships with ubiquitin, and which modify target proteins and lipids. These modifiers are processed, activated and conjugated to substrates by cognate enzymatic cascades. The attachment of substrates to Ubls alters the various properties of these substrates, such as function, interaction with the environment or turnover, and accordingly regulate key cellular processes, including DNA damage, cell cycle progression, metabolism, stress response, cellular differentiation, and protein homeostasis. Thus, it is not surprising that Ubls serve as tools to study the underlying mechanism involved in cellular health. We summarize current knowledge on the activity and mechanism of action of the S. cerevisiae Rub1, Smt3, Atg8, Atg12, Urm1 and Hub1 modifiers, all of which are highly conserved in organisms from yeast to humans.

Vesicle tethering and fusion promoted by LC3/GABARAP proteins is modulated by the ATG12-ATG5-ATG16L1 complex.

Recently, we have examined the membrane anchoring and subsequent lipidation of six members of the LC3/GABARAP protein family, together with their ability to promote membrane tethering and fusion. GABARAP and GABARAPL1 showed the highest activities. Differences found within LC3/GABARAP proteins suggested the existence of a lipidation threshold as a requisite for tethering and inter-vesicular lipid mixing. The presence of ATG12-ATG5-ATG16L1 (E3 in short) increased and accelerated LC3/GABARAP lipidation and subsequent vesicle tethering. However, E3 hampered LC3/GABARAP capacity to induce inter-vesicular lipid mixing and/or fusion. Our results suggest a model in which, together with the recently described inter-membrane lipid transfer mechanism, LC3/GABARAP could help in the phagophore expansion process through their ability to tether and fuse vesicles. The growing regions would be areas where the LC3/GABARAP proteins could be lipidated in the absence of E3, or else an independent regulatory mechanism would allow lipid/vesicle incorporation and phagophore growth when E3 was present.Abbreviations: Atg/ATG: autophagy-related protein (in yeast/human); E3: ATG12-ATG5-ATG16L1 complex; GABARAP: gamma-aminobutyric acid receptor associated protein; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3.

Effect of ATG12-ATG5-ATG16L1 autophagy E3-like complex on the ability of LC3/GABARAP proteins to induce vesicle tethering and fusion.

In macroautophagy, the autophagosome (AP) engulfs portions of cytoplasm to allow their lysosomal degradation. AP formation in humans requires the concerted action of the ATG12 and LC3/GABARAP conjugation systems. The ATG12-ATG5-ATG16L1 or E3-like complex (E3 for short) acts as a ubiquitin-like E3 enzyme, promoting LC3/GABARAP proteins anchoring to the AP membrane. Their role in the AP expansion process is still unclear, in part because there are no studies comparing six LC3/GABARAP family member roles under the same conditions, and also because the full human E3 was only recently available. In the present study, the lipidation of six members of the LC3/GABARAP family has been reconstituted in the presence and absence of E3, and the mechanisms by which E3 and LC3/GABARAP proteins participate in vesicle tethering and fusion have been investigated. In the absence of E3, GABARAP and GABARAPL1 showed the highest activities. Differences found within LC3/GABARAP proteins suggest the existence of a lipidation threshold, lower for the GABARAP subfamily, as a requisite for tethering and inter-vesicular lipid mixing. E3 increases and speeds up lipidation and LC3/GABARAP-promoted tethering. However, E3 hampers LC3/GABARAP capacity to induce inter-vesicular lipid mixing or subsequent fusion, presumably through the formation of a rigid scaffold on the vesicle surface. Our results suggest a model of AP expansion in which the growing regions would be areas where the LC3/GABARAP proteins involved should be susceptible to lipidation in the absence of E3, or else a regulatory mechanism would allow vesicle incorporation and phagophore growth when E3 is present.

LncRNA DDX11-AS1 Promotes Chemoresistance through LIN28A-Mediated ATG12 mRNA Stabilization in Breast Cancer.

INTRODUCTION: During breast cancer chemotherapy, the chemoresistance that frequently accompanies the treatment has become a big challenge. Long noncoding RNAs (LncRNAs) have been related to the development of chemoresistance in multiple cancer types. LncRNA DDX11-AS1 has shown a carcinogenic role in lung and colorectal cancer and was reported to enhance oxaliplatin resistance in gastric cancer and Taxol insensitivity in esophageal cancer. But its role in breast cancer chemotherapy drug resistance remains unknown. This study aimed to investigate the function and mechanism of lncRNA DDX11-AS1 in breast cancer chemoresistance. METHODS: The relationship between DDX11-AS1 and adriamycin (ADR) resistance was confirmed by qPCR, cell viability tests, and survival analysis. Then, RNA immunoprecipitation was conducted to evaluate the interaction between DDX11-AS1 and RNA-binding protein LIN28A. The regulation effect of LIN28A on autophagy-related genes ATG7 or ATG12 was detected by RNA stability assay and Western blot. Their correlation analysis was evaluated in GEO datasets and further validated by immunohistochemical results. The clinical significance of DDX11-AS1, ATG7, or ATG12 was evaluated by Kaplan-Meier Plotter analysis. RESULTS: Here, we reported DDX11-AS1 was significantly upregulated in chemoresistant breast cancer cells and overexpression of DDX11-AS1 promoted ADR resistance in breast cancer. LIN28A could interact with DDX11-AS1 and was involved in DDX11-AS1-mediated ADR resistance. Interfering with LIN28A reversed DDX11-AS1-induced ADR resistance. LIN28A could increase the protein level of ATG7 and ATG12 by increasing their mRNA stability. Survival analysis showed that ATG12 expression level was negatively correlated with the prognosis of breast cancer patients. CONCLUSION: This study clarifies the role of DDX11-AS1 in breast cancer chemoresistance and revealed a new mechanism, that is, interacting with LIN28A to stabilize ATG7 and ATG12 and jointly promote chemorefractory. These findings warrant further in vivo investigations to study DDX11-AS1 as a potential target to overcome chemoresistance.

Danhong injection alleviates cerebral ischemia-reperfusion injury by inhibiting autophagy through miRNA-132-3p/ATG12 signal axis.

ETHNOPHARMACOLOGICAL RELEVANCE: Danhong injection (DHI) is a renowned traditional Chinese medicine often used clinically to treat cardiovascular and cerebrovascular diseases. Studies have shown that DHI can significantly alter microRNA (miRNA) expression in the brain tissue. Therefore, exploring specific miRNAs' regulatory mechanisms during treatment with DHI is essential. AIM OF THE STUDY: To investigate DHI's regulatory mechanism on cerebral autophagy in rats with cerebral ischemia-reperfusion injury (CIRI). MATERIAL AND METHODS: Rats were randomly divided into the sham, middle cerebral artery occlusion (MCAO) model, and DHI-treatment groups. The extent of brain damage was evaluated using triphenyl tetrazolium chloride and hematoxylin-eosin staining. Hippocampal cell autophagy was observed using transmission electron microscopy. Autophagy-related proteins were analyzed using western blotting. Differentially expressed miRNAs were screened using high-throughput and real-time quantitative reverse transcription PCR. The relationship between miR-132-3p and ATG12 was confirmed using a dual-luciferase assay. The miR-132-3p mimics and inhibitors were transfected into PC12 cells subjected to oxygen-glucose deprivation (OGD) in vitro and MCAO model rats in vivo. RESULTS: DHI significantly altered the miRNA expression profile in rat brain tissues. The pathological changes in the brain tissues were improved, and the autophagic hippocampal cell vehicles were significantly reduced after DHI treatment. miRNA-132-3p, one of the miRNAs with a significantly different expression, was screened. Kyoto Encyclopedia of Genes and Genomes signal pathway analysis showed that its target genes were closely related to autophagy. Western blotting revealed that the p-PI3K, p-AKT, and mTOR expression increased significantly; AMPK, ULK1, ATG12, ATG16L1, and LC3II/I were downregulated in the DHI group. Dual-luciferase reporter gene experiments showed that miRNA-132-3p could target the ATG12 3'-UTR region directly. In vitro, miRNA-132-3p had a protective effect on OGD/R-induced oxidative stress injury in PC12 cells, improving cell viability, and affecting the expression of autophagy pathway-related proteins. In vivo transfection experiments showed that miR-132-3p could regulate ATG12 expression in CIRI rats' lateral brain tissue, affecting the autophagy signaling pathway. miR-132-3p overexpression reduces CIRI-induced autophagy and protects neurons. CONCLUSION: This study showed that DHI inhibits neuronal autophagy after cerebral ischemia-reperfusion. This may have resulted from miR-132-3p targeting ATG12 and regulating the autophagy signaling pathway protein expression.

Unravelling the In Vitro and In Vivo Anti-Helicobacter pylori Effect of Delphinidin-3-O-Glucoside Rich Extract from Pomegranate Exocarp: Enhancing Autophagy and Downregulating TNF-α and COX2.

Fruits containing antioxidants, e.g., anthocyanins, exhibit antimicrobial activities. The emergence of drug resistance represents a major challenge in eradicating H. pylori. The current study aims to explore the effect of pomegranate exocarp anthocyanin methanol extract (PEAME) against H. pylori isolates recovered from antral gastric biopsies. The UPLC-PDA-MS/MS and 1H NMR analyses indicated delphinidin-3-O-glucoside as the major anthocyanin in the extract. The PEAME showed activity against all tested resistant isolates in vitro recording minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 128 and 256 µg/mL, respectively. In vivo investigation included evaluation of the rat gastric mucosa for malondialdehyde (MDA), catalase activity, COX2, TNF-α, and key autophagy gene expression. The combination of pomegranate with metronidazole markedly reduced the viable count of H. pylori and the level of COX2, with alleviation of H. pylori-induced inflammation and oxidative stress (reduction of MDA, p-value < 0.001; and increase in catalase activity, p-value < 0.001). Autophagy gene expression was significantly upregulated upon treatment, whereas TNF-α was downregulated. In conclusion, we comprehensively assessed the effect of PEAME against H. pylori isolates, suggesting its potential in combination with metronidazole for eradication of this pathogen. The beneficial effect of PEAME may be attributed to its ability to enhance autophagy.

ATG5: A central autophagy regulator implicated in various human diseases.

Autophagy, an intracellular conserved degradative process, plays a central role in the renewal/recycling of a cell to maintain the homeostasis of nutrients and energy within the cell. ATG5, a key component of autophagy, regulates the formation of the autophagosome, a hallmark of autophagy. ATG5 binds with ATG12 and ATG16L1 resulting in E3 like ligase complex, which is necessary for autophagosome expansion. Available data suggest that ATG5 is indispensable for autophagy and has an imperative role in several essential biological processes. Moreover, ATG5 has also been demonstrated to possess autophagy-independent functions that magnify its significance and therapeutic potential. ATG5 interacts with various molecules for the execution of different processes implicated during physiological and pathological conditions. Furthermore, ATG5 genetic variants are associated with various ailments. This review discusses various autophagy-dependent and autophagy-independent roles of ATG5, highlights its various deleterious genetic variants reported until now, and various studies supporting it as a potential drug target.

Differential effects of 5-fluorouracil and oxaliplatin on autophagy in chemoresistant colorectal cancer cells.

Macroautophagy (hereafter autophagy) is one of the adaptive pathways that contribute to cancer cell chemoresistance. Despite the fact that autophagy can both promote and inhibit cell death, there is mounting evidence that in the context of anticancer treatment, it predominantly functions as a cell survival mechanism. Therefore, silencing of key autophagy genes emerges as a potent strategy to reduce chemoresistance. Though the importance of autophagy in chemoresistance is established, the changes in autophagy in the case of acquired chemoresistance are poorly understood. In this study, we aimed to determine the changes of autophagy in the cellular model of acquired chemoresistance of colorectal cancer cell lines HCT116 and SW620, induced by 5-fluorouracil (5-FU) or oxaliplatin (OxaPt) treatment, and determine the susceptible factors for autophagy inhibition. Our results demonstrate that in the context of autophagy, 5-FU and OxaPt have different effects on HCT116 and SW620 cell lines and their chemoresistant sublines. 5-FU inhibits autophagic flux, while changes in the flux after OxaPt treatment are cell type- and dose-dependent, inducing autophagy reduction or increase. The chemoresistant subline of HCT116 cells derived by OxaPt differs from the subline derived by 5-FU treatment - it responds to OxaPt by upregulating ATG7 protein level and autophagic flux, in contrast to downregulation in cells derived by 5-FU. Moreover, 5-FU and OxaPt treatments significantly modulate protein levels of core-autophagy proteins ATG7 and ATG12. The potential effects of 5-FU and OxaPt on ATG protein levels should be taken into account to reduce chemoresistance by applying small interferingRNAs, targeting ATG proteins.

The ATG5 interactome links clathrin-mediated vesicular trafficking with the autophagosome assembly machinery.

Autophagosome formation involves the sequential actions of conserved ATG proteins to coordinate the lipidation of the ubiquitin-like modifier Atg8-family proteins at the nascent phagophore membrane. Although the molecular steps driving this process are well understood, the source of membranes for the expanding phagophore and their mode of delivery are only now beginning to be revealed. Here, we have used quantitative SILAC-based proteomics to identify proteins that associate with the ATG12-ATG5 conjugate, a crucial player during Atg8-family protein lipidation. Our datasets reveal a strong enrichment of regulators of clathrin-mediated vesicular trafficking, including clathrin heavy and light chains, and several clathrin adaptors. Also identified were PIK3C2A (a phosphoinositide 3-kinase involved in clathrin-mediated endocytosis) and HIP1R (a component of clathrin vesicles), and the absence of either of these proteins alters autophagic flux in cell-based starvation assays. To determine whether the ATG12-ATG5 conjugate reciprocally influences trafficking within the endocytic compartment, we captured the cell surface proteomes of autophagy-competent and autophagy-incompetent mouse embryonic fibroblasts under fed and starved conditions. We report changes in the relative proportions of individual cell surface proteins and show that cell surface levels of the SLC7A5-SLC3A2 amino acid transporter are influenced by autophagy capability. Our data provide evidence for direct regulatory coupling between the ATG12-ATG5 conjugate and the clathrin membrane trafficking system and suggest candidate membrane proteins whose trafficking within the cell may be modulated by the autophagy machinery. Abbreviations: ATG, autophagy related; BafA1, bafilomycin A1; GFP, green fluorescent protein; HIP1R, huntingtin interacting protein 1 related; MEF, mouse embryo fibroblast; PIK3C2A, phosphatidylinositol-4-phosphate 3-kinase catalytic subunit type 2 alpha; SILAC, stable isotope labelling with amino acids in culture; SQSTM1, sequestosome 1; STRING, search tool for the retrieval of interacting genes/proteins.

DJ-1 activates the Atg5-Atg12-Atg16L1 complex via Sirt1 to influence microglial polarization and alleviate cerebral ischemia/reperfusion-induced inflammatory injury.

BACKGROUND: After cerebral ischemia/reperfusion (I/R) injury, activated microglia can be polarized towards different phenotypes (the proinflammatory M1 phenotype or the anti-inflammatory M2 phenotype) to regulate neuroinflammation. Our previous research showed that DJ-1 has anti-inflammatory effects in cerebral I/R. Here, we examined whether the neuroprotective effect of DJ-1 is related to the autophagy-associated Atg5-Atg12-Atg161L1 complex and whether Sirt1 is involved in the influence of DJ-1 by mediating microglial polarization and ameliorating cerebral I/R injury. METHODS: To answer these questions, we adopted the middle cerebral artery occlusion/reperfusion (MCAO/R) model to simulate I/R injury, knocked down the expression of DJ-1 with siRNA, and used the chemical inhibitor EX-527 to inhibit the expression of Sirt1. Related indexes were evaluated by Western blotting, immunoprecipitation and transmission electron microscopy. RESULTS: Interference with DJ-1 promotes the polarization of microglia from the anti-inflammatory phenotype to the proinflammatory phenotype. Addition of a Sirt1 inhibitor following DJ-1 interference enhances the effect of DJ-1 interference on microglial polarization, decreases the level of the Atg5-Atg12-Atg16L1 complex, and inhibits autophagy. CONCLUSION: These results suggest that DJ-1 regulates the polarization of microglia during cerebral I/R injury, possibly by activating the Atg5-Atg12-Atg16L1 complex through Sirt1 to promote autophagy.

Ornithine decarboxylase functions in both autophagy and apoptosis in response to ultraviolet B radiation injury.

We present a mechanism for how ornithine decarboxylase (ODC) regulates the crosstalk between autophagy and apoptosis. In cancer cells, low-intensity ultraviolet B (UVBL ) induces autophagy while high-intensity UVB (UVBH ) induces apoptosis. Overexpression of ODC decreases UVBL -induced autophagy by inhibiting Atg5-Atg12 conjugation and suppressing the expression of autophagy markers LC3, Atg7, Atg12, and BECN1 proteins. In contrast, when ODC-overexpressing cells are exposed to UVBH radiation, the levels of LC3-II, Atg5-Atg12 conjugate, BECN1, Atg7, and Atg12 increase, while the apoptosis marker cleaved-PARP proteins decrease, indicating that ODC overexpression induced UVBH -induced autophagy but inhibited UVBH -induced cellular apoptosis. Additionally, when exposed to UVBH radiation, silencing BECN1, Atg5, and Atg12 genes results in a decrease in the level of LC3-II proteins but an increase in the level of cleaved-PARP proteins, and apoptotic bodies were significantly increased while autophagosomes were significantly decreased. These findings imply that ODC inhibits apoptosis in cells via the autophagy pathway. The role of Atg12 in ODC-overexpressing cells exposed to UVBH radiation is investigated using site-directed mutagenesis. Our results indicate that the Atg12-D111S mutant has increased cell survival. The Atg12-ΔG186 mutant impairs autophagy and enhances apoptosis. We demonstrate that when ODC-overexpressing cells are silenced for the Atg12 protein, autophagy and apoptosis are strongly affected, and ODC-induced autophagy protects against UVBH -induced apoptosis via the Atg12 protein.

Adaptor SH3BGRL drives autophagy-mediated chemoresistance through promoting PIK3C3 translation and ATG12 stability in breast cancers.

Acquired chemotherapy resistance is one of the main culprits in the relapse of breast cancer. But the underlying mechanism of chemotherapy resistance remains elusive. Here, we demonstrate that a small adaptor protein, SH3BGRL, is not only elevated in the majority of breast cancer patients but also has relevance with the relapse and poor prognosis of breast cancer patients. Functionally, SH3BGRL upregulation enhances the chemoresistance of breast cancer cells to the first-line doxorubicin treatment through macroautophagic/autophagic protection. Mechanistically, SH3BGRL can unexpectedly bind to ribosomal subunits to enhance PIK3C3 translation efficiency and sustain ATG12 stability. Therefore, inhibition of autophagy or silence of PIK3C3 or ATG12 can effectively block the driving effect of SH3BGRL on doxorubicin resistance of breast cancer cells in vitro and in vivo. We also validate that SH3BGRL expression is positively correlated with that of PIK3C3 or ATG12, as well as the constitutive occurrence of autophagy in clinical breast cancer tissues. Taken together, our data reveal that SH3BGRL upregulation would be a key driver to the acquired chemotherapy resistance through autophagy enhancement in breast cancer while targeting SH3BGRL could be a potential therapeutic strategy against breast cancer.Abbreviations: ABCs: ATP-binding cassette transporters; Act D: actinomycin D; ACTB/ß-actin: actin beta; ATG: autophagy-related; Baf A1: bafilomycin A1; CASP3: caspase 3; CHX: cycloheximide; CQ: chloroquine; Dox: doxorubicin; FBS: fetal bovine serum; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GEO: gene expression omnibus; GFP: green fluorescent protein; G6PD: glucose-6-phosphate dehydrogenase; GSEA: gene set enrichment analysis; IHC: immunochemistry; KEGG: Kyoto Encyclopedia of Genes and Genomes; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; 3-MA: 3-methyladenine; mRNA: messenger RNA; PIK3C3: phosphatidylinositol 3-kinase catalytic subunit type 3; SH3BGRL: SH3 domain binding glutamate-rich protein-like; SQSTM1/p62: sequestosome 1; ULK1: unc-51 like autophagy activating kinase 1.