共查询到20条相似文献,搜索用时 46 毫秒
1.
HAMLET is a complex of oleic acids and decalcified α-lactalbumin that was discovered to selectively kill tumor cells both in vitro and in vivo. Autophagy is an important cellular process involved in drug-induced cell death of glioma cells. We treated U87MG human glioma cells with HAMLET and found that the cell viability was significantly decreased and accompanied with the activation of autophagy. Interestingly, we observed an increase in p62/SQSTM1, an important substrate of autophagosome enzymes, at the protein level upon HAMLET treatment for short periods. To better understand the functionality of autophagy and p62/SQSTM1 in HAMLET-induced cell death, we modulated the level of autophagy or p62/SQSTM1 with biochemical or genetic methods. The results showed that inhibition of autophagy aggravated HAMLET-induced cell death, whereas activation of authophagy attenuated this process. Meanwhile, we found that overexpression of wild-type p62/SQSTM1 was able to activate caspase-8, and then promote HAMLET-induced apoptosis, whereas knockdown of p62/SQSTM1 manifested the opposite effect. We further demonstrated that the function of p62/SQSTM1 following HAMLET treatment required its C-terminus UBA domain. Our results indicated that in addition to being a marker of autophagy activation in HAMLET-treated glioma cells, p62/SQSTM1 could also function as an important mediator for the activation of caspase-8-dependent cell death. 相似文献
2.
Autophagy regulates cell survival (or cell death in several cases), whereas apoptosis regulates cell death. However, the relationship between autophagy and apoptosis and the regulative mechanism is unclear. We report that steroid hormone 20-hydroxyecdysone (20E) promotes switching from autophagy to apoptosis by increasing intracellular calcium levels in the midgut of the lepidopteran insect Helicoverpa armigera. Autophagy and apoptosis sequentially occurred during midgut programmed cell death under 20E regulation, in which lower concentrations of 20E induced microtubule-associated protein 1 light chain 3–phosphatidylethanolamine (LC3–II, also known as autophagy-related gene 8, ATG8) expression and autophagy. High concentrations of 20E induced cleavage of ATG5 to NtATG5 and pro-caspase-3 to active caspase-3, which led to a switch from autophagy to apoptosis. Blocking autophagy by knockdown of ATG5, ATG7, or ATG12, or with the autophagy inhibitor 3-methyladenine, inhibited 20E-induced autophagy and apoptosis. Blocking apoptosis by using the apoptosis inhibitor Ac-DEVD-CHO did not prevent 20E-induced autophagy, suggesting that apoptosis relies on autophagy. ATG5 knockdown resulted in abnormal pupation and delayed pupation time. High concentrations of 20E induced high levels of intracellular Ca2+, NtATG5, and active caspase-3, which mediated the switch from autophagy to apoptosis. Blocking 20E-mediated increase of cellular Ca2+ caused a decrease of NtATG5 and active caspase-3 and repressed the transformation from autophagy to apoptosis, thereby promoting cell survival. 20E induces an increase in the concentration of intracellular Ca2+, thereby switching autophagic cell survival to apoptotic cell death. 相似文献
3.
Hideki Kimura Kazuko Kamiyama Toru Imamoto Izumi Takeda Shinya Masunaga Mamiko Kobayashi Daisuke Mikami Naoki Takahashi Kenji Kasuno Takeshi Sugaya Masayuki Iwano 《Biochemistry and Biophysics Reports》2022
The main lesion of cisplatin nephrotoxicity is damage to proximal tubular cells due to increased apoptosis via the mitochondrial and death receptor pathways, which may be alleviated by appropriate promotion of autophagy. Fenofibrate, a peroxisome proliferator-activated receptor-alpha (PPAR-α) activator, is recently reported to promote autophagy as well as protect against cisplatin nephrotoxicity, although the mechanisms were only partially analyzed. Here, the detailed mechanisms of these putative protective effects were investigated in a murine renal proximal tubular (mProx) cell line. Fenofibrate attenuated cisplatin-induced apoptosis of mProx cells based on flow cytometry. As for the mitochondrial apoptotic pathway, the reagent reduced cisplatin-stimulated caspase-3 activation by decreasing the phosphorylation of p53, JNK, and 14-3-3, cytosolic and mitochondrial Puma accumulation, cytochrome C release to the cytosol, and resulting cytosolic caspase-9 activation. Fenofibrate also decreased cisplatin-stimulated activation of caspases-8 by suppressing MAPK and NFkB pathways and reducing the gene expression of TNF-α, TL1A, and Fas, main mediators of the death receptor apoptotic pathway. Autophagy defined by p62 reduction and an increase in LC3 II/I was promoted by fenofibrate in mProx cells under starvation. Autophagy inhibition using 3-MA further increased basal and cisplatin-induced caspase-3 and -8 activation, but had no influence on the inhibitory effects of fenofibrate on caspase activation. In conclusion, our study suggests fenofibrate to be a candidate agent to mitigate cisplatin nephrotoxicity by inhibiting the mitochondrial and death apoptotic pathways rather than by promoting autophagy. 相似文献
4.
Young MM Takahashi Y Khan O Park S Hori T Yun J Sharma AK Amin S Hu CD Zhang J Kester M Wang HG 《The Journal of biological chemistry》2012,287(15):12455-12468
Autophagy and apoptosis are two evolutionarily conserved processes that regulate cell fate in response to cytotoxic stress. However, the functional relationship between these two processes remains far from clear. Here, we demonstrate an autophagy-dependent mechanism of caspase-8 activation and initiation of the apoptotic cascade in response to SKI-I, a pan-sphingosine kinase inhibitor, and bortezomib, a proteasome inhibitor. Autophagy is induced concomitantly with caspase-8 activation, which is responsible for initiation of the caspase cascade and the mitochondrial amplification loop that is required for full execution of apoptosis. Inhibition of autophagosome formation by depletion of Atg5 or Atg3 results in a marked suppression of caspase-8 activation and apoptosis. Although caspase-8 self-association depends on p62/SQSTM1, its self-processing requires the autophagosomal membrane. Caspase-8 forms a complex with Atg5 and colocalizes with LC3 and p62. Moreover, FADD, an adaptor protein for caspase-8 activation, associates with Atg5 on Atg16L- and LC3-positive autophagosomal membranes and loss of FADD suppresses cell death. Taken together, these results indicate that the autophagosomal membrane serves as a platform for an intracellular death-inducing signaling complex (iDISC) that recruits self-associated caspase-8 to initiate the caspase-8/-3 cascade. 相似文献
5.
Yueyue Yu Sheng-Ru Shiou Yuee Guo Lei Lu Maria Westerhoff Jun Sun Elaine O. Petrof Erika C. Claud 《PloS one》2013,8(7)
Neonatal necrotizing enterocolitis (NEC) is a devastating gastrointestinal disease of preterm infants. Increased intestinal epithelium permeability is an early event in NEC pathogenesis. Autophagy and apoptosis are induced by multiple stress pathways which may impact the intestinal barrier, and they have been associated with pathogenesis of diverse gastrointestinal diseases including inflammatory bowel disease. Using both in vitro and in vivo models, this study investigates autophagy and apoptosis under experimental NEC stresses. Furthermore this study evaluates the effect of erythropoietin (Epo), a component of breast milk previously shown to decrease the incidence of NEC and to preserve intestinal barrier function, on intestinal autophagy and apoptosis. It was found that autophagy and apoptosis are both rapidly up regulated in NEC in vivo as indicated by increased expression of the autophagy markers Beclin 1 and LC3II, and by evidence of apoptosis by TUNEL and cleaved caspase-3 staining. In the rat NEC experimental model, autophagy preceded the onset of apoptosis in intestine. In vitro studies suggested that Epo supplementation significantly decreased both autophagy and apoptosis via the Akt/mTOR signaling pathway and the MAPK/ERK pathway respectively. These results suggest that Epo protects intestinal epithelium from excessive autophagy and apoptosis in experimental NEC. 相似文献
6.
Andrew Brennan Robert Layfield Jed Long Huw E.L. Williams Neil J. Oldham Daniel Scott Mark S. Searle 《The Journal of biological chemistry》2022,298(2)
Recognition of human autophagy-related 8 (hATG8) proteins by autophagy receptors represents a critical step within this cellular quality control system. Autophagy impairment is known to be a pathogenic mechanism in the motor neuron disorder amyotrophic lateral sclerosis (ALS). Overlapping but specific roles of hATG8 proteins belonging to the LC3 and GABARAP subfamilies are incompletely understood, and binding selectivity is typically overlooked. We previously showed that an ALS-associated variant of the SQSTM1/p62 (p62) autophagy receptor bearing an L341V mutation within its ATG8-interacting motif (AIM) impairs recognition of LC3B in vitro, yielding an autophagy-deficient phenotype. Improvements in understanding of hATG8 recognition by AIMs now distinguish LC3-interaction and GABARAP-interaction motifs and predict the effects of L341V substitution may extend beyond loss of function to biasing AIM binding preference. Through biophysical analyses, we confirm impaired binding of the L341V-AIM mutant to LC3A, LC3B, GABARAP, and GABARAPL1. In contrast, p62 AIM interactions with LC3C and GABARAPL2 are unaffected by this mutation. Isothermal titration calorimetry and NMR investigations provided insights into the entropy-driven GABARAPL2/p62 interaction and how the L341V mutation may be tolerated. Competition binding demonstrated reduced association of the L341V-AIM with one hATG8 manifests as a relative increase in association with alternate hATG8s, indicating effective reprogramming of hATG8 selectivity. These data highlight how a single AIM peptide might compete for binding with different hATG8s and suggest that the L341V-AIM mutation may be neomorphic, representative of a disease mechanism that likely extends into other human disorders. 相似文献
7.
Eldecalcitol (ED-71) is a new type of vitamin D analog, and vitamin D has been reported to have therapeutic effects in infectious disease, autoimmune disease, and cancer. However, the anti-cancer effect of ED-71 remains unclear. The objective of this study was to explore the anti-cancer effect of ED-71 in human osteosarcoma cells and to identify the related mechanism. The CCK8 assay results showed that ED-71 inhibited MG-63 cell viability in dose and time dependent manners. Cloning and Transwell invasion assays showed that ED-71 inhibited clonal and invasion ability of MG-63 cells. Flow cytometry results showed ED-71 the G2/M cycle arrest rate, apoptosis, and intracellular ROS. Western blot was used to detect cleaved-caspase-3, Bax, Bcl-2, LC3-II/LC3-I, and P62 levels and the mTOR pathway. The increase of LC3-II and P62 indicated that ED-71 induced the formation of autophagosomes and inhibited autophagy flux. Furthermore, ED-71-induced apoptosis was weakened after adding 3-methyladenine and ED-71-induced early autophagy was weakened by caspase-3 inhibitor (Z-VAD-FMK), which indicated the two processes active each other in the presence of ED-71. Furthermore, N-acetylcysteine (NAC) pretreatment reversed the ED-71-treatment outcomes, including increased apoptosis and autophagy and inhibition of the PI3K/Akt/mTOR pathway. In conclusion, our results reveal that ED-71 induced G2/M arrest, apoptosis and autophagy in MG-63 cells by accumulating ROS to suppress the PI3K/Akt/mTOR signaling pathway 相似文献
8.
Cristina P.R. Xavier Cristovao F. Lima Dalila F.N. Pedro Jonathan M. Wilson Karsten Kristiansen Cristina Pereira-Wilson 《The Journal of nutritional biochemistry》2013,24(4):706-712
Colorectal carcinomas (CRCs) with P53 mutations have been shown to be resistant to chemotherapy with 5-fluorouracil (5-FU), the most widely used chemotherapeutic drug for CRC treatment. Autophagy is emerging as a promising therapeutic target for drug-resistant tumors. In the present study, we tested the effects of ursolic acid (UA), a natural triterpenoid, on cell death mechanisms and its effects in combination with 5-FU in the HCT15 p53 mutant apoptosis-resistant CRC cell line. The involvement of UA in autophagy and its in vivo efficacy were evaluated.Our data show that UA induces apoptosis independent of caspases in HCT15 cells and enhances 5-FU effects associated with an activation of c-jun N-terminal kinase (JNK). In this cell line, where this compound has a more pronounced effect on the induction of cell death compared to 5-FU, apoptosis corresponds only to a small percentage of the total cell death induced by UA. UA also modulated autophagy by inducing the accumulation of LC3 and p62 levels with involvement of JNK pathway, which indicates a contribution of autophagy on JNK-dependent induction of cell death by UA. By using nude mice xenografted with HCT15 cells, we verified that UA was also active in vivo decreasing tumor growth rate.In conclusion, this study shows UA's anticancer potential both in vitro and in vivo. Induction of cell death and modulation of autophagy in CRC-resistant cells were shown to involve JNK signaling. 相似文献
9.
Wei Li Nargis Sultana Nabeel Siraj Liam J Ward Monika Pawlik Efrat Levy Stefan Jovinge Eva Bengtsson Xi‐Ming Yuan 《Journal of cellular and molecular medicine》2016,20(9):1664-1672
Autophagy dysfunction in mouse atherosclerosis models has been associated with increased lipid accumulation, apoptosis and inflammation. Expression of cystatin C (CysC) is decreased in human atheroma, and CysC deficiency enhances atherosclerosis in mice. Here, we first investigated the association of autophagy and CysC expression levels with atheroma plaque severity in human atherosclerotic lesions. We found that autophagy proteins Atg5 and LC3β in advanced human carotid atherosclerotic lesions are decreased, while markers of dysfunctional autophagy p62/SQSTM1 and ubiquitin are increased together with elevated levels of lipid accumulation and apoptosis. The expressions of LC3β and Atg5 were positively associated with CysC expression. Second, we investigated whether CysC expression is involved in autophagy in atherosclerotic apoE‐deficient mice, demonstrating that CysC deficiency (CysC?/?) in these mice results in reduction of Atg5 and LC3β levels and induction of apoptosis. Third, macrophages isolated from CysC?/? mice displayed increased levels of p62/SQSTM1 and higher sensitivity to 7‐oxysterol‐mediated lysosomal membrane destabilization and apoptosis. Finally, CysC treatment minimized oxysterol‐mediated cellular lipid accumulation. We conclude that autophagy dysfunction is a characteristic of advanced human atherosclerotic lesions and is associated with reduced levels of CysC. The deficiency of CysC causes autophagy dysfunction and apoptosis in macrophages and apoE‐deficient mice. The results indicate that CysC plays an important regulatory role in combating cell death via the autophagic pathway in atherosclerosis. 相似文献
10.
《Autophagy》2013,9(4):449-454
Autophagy is a cellular stress response that results in the activation of a lysosomal degradation pathway. In this report, we showed that cationic lipids, a common-used class of transfection reagents, induced genuine autophagy in mammalian cells. Extensive LC3 dot formation was observed by treatment with cationic lipids (with or without DNA), but not neutral lipids, in a HeLa cell line stably expressing GFP-LC3 (HeLa-LC3). Further proofs for autophagy were obtained by the co-localization of the LC3 dots with lysosome-specific staining patterns, observation of LC3-I to LC3-II form conversion and appearance of autophagic vacuoles under TEM. The autophagic flux assay with bafilomycin A1 and degradation of p62/SQSTM1 suggested that the autophagy induced by cationic lipids was primarily due to increased formation of autophagosomes and not decreased turnover. Moreover, cationic lipids induced autophagy in an mTOR-independent manner. 相似文献
11.
Autophagy regulates cell survival and cell death upon various cellular stresses, yet the molecular signaling events involved are not well defined. Here, we established the function of a proteolytic Cyclin E fragment (p18-CycE) in DNA damage-induced autophagy, apoptosis, and senescence. p18-CycE was identified in hematopoietic cells undergoing DNA damage-induced apoptosis. In epithelial cells exposed to DNA damage, chronic but not transient expression of p18-CycE leads to higher turnover of LC3 I/II and increased emergence of autophagosomes and autolysosomes. Levels of p18-CycE, which was generated by proteolytic cleavage of endogenous Cyclin E, were greatly increased by chloroquine and correlated with LC 3II conversion. Preventing p18-CycE genesis blocked conversion of LC3 I to LC3 II. Upon DNA damage, cytoplasmic ataxia-telangiectasia-mutated (ATM) was phosphorylated in p18-CycE-expressing cells resulting in sustained activation of the adenosine-mono-phosphate-dependent kinase (AMPK). These lead to sustained activation of mammalian autophagy-initiating kinase ULK1, which was abrogated upon inhibiting ATM and AMPK phosphorylation. Moreover, p18-CycE was degraded via autophagy followed by induction of senescence. Both autophagy and senescence were prevented by inhibiting autophagy, which leads to increased apoptosis in p18-CycE-expressing cells by stabilizing p18-CycE expression. Senescence was further associated with cytoplasmic co-localization and degradation of p18-CycE and Ku70. In brief, chronic p18-CycE expression-induced autophagy leads to clearance of p18-CycE following DNA damage and induction of senescence. Autophagy inhibition stabilized the cytoplasmic p18-CycE-Ku70 complex leading to apoptosis. Thus, our findings define how chronic apoptotic stress and DNA damage initiate autophagy and regulate cell survival through senescence and/or apoptosis. 相似文献
12.
Lin Qi Xue Sun Feng-E Li Bao-Song Zhu Frank K. Braun Zhi-Qiang Liu Jin-Le Tang Chao Wu Fei Xu Hui-Han Wang Luis A. Velasquez Kui Zhao Feng-Rui Lei Ji-Gang Zhang Yun-Tian Shen Jian-Xuan Zou Hui-Min Meng Gang-Li An Lin Yang Xing-Ding Zhang 《PloS one》2015,10(11)
Impairments in mitochondrial energy metabolism are thought to be involved in many neurodegenerative diseases. The mitochondrial inhibitor 3-nitropropionic acid (3-NP) induces striatal pathology mimicking neurodegeneration in vivo. Previous studies showed that 3-NP also triggered autophagy activation and apoptosis. In this study, we focused on the high-mobility group box 1 (HMGB1) protein, which is important in oxidative stress signaling as well as in autophagy and apoptosis, to explore whether the mechanisms of autophagy and apoptosis in neurodegenerative diseases are associated with metabolic impairment. To elucidate the role of HMGB1 in striatal degeneration, we investigated the impact of HMGB1 on autophagy activation and cell death induced by 3-NP. We intoxicated rat striata with 3-NP by stereotaxic injection and analyzed changes in expression HMGB1, proapoptotic proteins caspase-3 and phospho-c-Jun amino-terminal kinases (p-JNK). 3-NP–induced elevations in p-JNK, cleaved caspase-3, and autophagic marker LC3-II as well as reduction in SQSTM1 (p62), were significantly reduced by the HMGB1 inhibitor glycyrrhizin. Glycyrrhizin also significantly inhibited 3-NP–induced striatal damage. Neuronal death was replicated by exposing primary striatal neurons in culture to 3-NP. It was clear that HMGB1 was important for basal autophagy which was shown by rescue of cells through HMGB1 targeting shRNA approach.3-NP also induced the expression of HMGB1, p-JNK, and LC3-II in striatal neurons, and p-JNK expression was significantly reduced by shRNA knockdown of HMGB1, an effect that was reversed by exogenously increased expression of HMGB1. These results suggest that HMGB1 plays important roles in signaling for both autophagy and apoptosis in neurodegeneration induced by mitochondrial dysfunction. 相似文献
13.
摘要 目的:观察雷公藤甲素诱导肝细胞选择性自噬的水平。方法:在雷公藤甲素给药处理小鼠的尾静脉高压注射GFP-LC3质粒,制备肝细胞自噬示踪模型,观察雷公藤甲素在动物体内诱导肝细胞自噬的水平。在GFP-LC3稳定表达的L02细胞株中转入RFP-P62质粒,用活细胞工作站和荧光显微镜动态观察雷公藤甲素诱导L02细胞选择性自噬的轮廓,同时也观察细胞自噬复合体LC3-P62的变化。结果:动物实验结果表明,雷公藤甲素可显著诱导肝细胞自噬体的形成,Western blot结果显示P62蛋白和LC3II蛋白的表达趋势一致。活细胞动态观察及免疫荧光双标记实验结果表明LC3-P62存在共定位,提示雷公藤甲素可诱导肝细胞自噬流的形成。结论:雷公藤甲素可诱导肝细胞选择自噬,其生物学意义可能与肝细胞损伤后修复相关。 相似文献
14.
Hyun-Kyu An Kyoung-Sook Kim Ji-Won Lee Mi-Hyun Park Hyung-In Moon Shin-Ji Park Ji-Sue Baik Cheorl-Ho Kim Young-Choon Lee 《PloS one》2014,9(12)
Anticancer properties and mechanisms of mimulone (MML), C-geranylflavonoid isolated from the Paulownia tomentosa fruits, were firstly elucidated in this study. MML prevented cell proliferation in a dose- and time-dependent way and triggered apoptosis through the extrinsic pathway in A549 human lung adenocarcinoma cells. Furthermore, MML-treated cells displayed autophagic features, such as the formation of autophagic vacuoles, a primary morphological feature of autophagy, and the accumulation of microtubule-associated protein 1 light chain 3 (LC3) puncta, another typical maker of autophagy, as determined by FITC-conjugated immunostaining and monodansylcadaverine (MDC) staining, respectively. The expression levels of LC3-I and LC3-II, specific markers of autophagy, were also augmented by MML treatment. Autophagy inhibition by 3-methyladenine (3-MA), pharmacological autophagy inhibitor, and shRNA knockdown of Beclin-1 reduced apoptotic cell death induced by MML. Autophagic flux was not significantly affected by MML treatment and lysosomal inhibitor, chloroquine (CQ) suppressed MML-induced autophagy and apoptosis. MML-induced autophagy was promoted by decreases in p53 and p-mTOR levels and increase of p-AMPK. Moreover, inhibition of p53 transactivation by pifithrin-α (PFT-α) and knockdown of p53 enhanced induction of autophagy and finally promoted apoptotic cell death. Overall, the results demonstrate that autophagy contributes to the cytotoxicity of MML in cancer cells harboring wild-type p53. This study strongly suggests that MML is a potential candidate for an anticancer agent targeting both autophagy and apoptotic cell death in human lung cancer. Moreover, co-treatment of MML and p53 inhibitor would be more effective in human lung cancer therapy. 相似文献
15.
16.
Environmental exposure to cadmium (Cd) links to neurodegenerative disorders. Autophagy plays an important role in controlling cell survival/death. However, how autophagy contributes to Cd's neurotoxicity remains enigmatic. Here, we show that Cd induced significant increases in autophagosomes with a concomitant elevation of LC3-II and p62 in PC12 cells and primary neurons. Using autophagy inhibitor 3-MA, we demonstrated that Cd-increased autophagosomes contributed to neuronal apoptosis. Impairment of Cd on autophagic flux was evidenced by co-localization of mCherry and GFP tandem-tagged LC3 puncta in the cells. This is further supported by the findings that administration of chloroquine (CQ) potentiated the basic and Cd-elevated LC3-II and p62 levels, autophagosome accumulation and cell apoptosis, whereas rapamycin relieved the effects in the cells in response to Cd. Subsequently, we noticed that Cd evoked the phosphorylation of Akt and BECN1. Silencing BECN1 and especially expression of mutant BECN1 (Ser295A) attenuated Cd-increased autophagosomes and cell death. Of note, inhibition of Akt with Akt inhibitor X, or ectopic expression of dominant negative Akt (dn-Akt), in the presence or absence of 3-MA, significantly alleviated Cd-triggered phosphorylation of Akt and BECN1, autophagosomes, and apoptosis. Importantly, we found that Cd activation of Akt functioned in impairing autophagic flux. Collectively, these results indicate that Cd results in accumulation of autophagosomes-dependent apoptosis through activating Akt-impaired autophagic flux in neuronal cells. Our findings underscore that inhibition of Akt to improve autophagic flux is a promising strategy against Cd-induced neurotoxicity and neurodegeneration. 相似文献
17.
《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》2023,1870(7):119530
ObjectiveThe catabolic process of autophagy is arousing the attention of researchers studying diabetic retinopathy (DR), but the role and molecular mechanism of autophagy in DR are still unclear.MethodsAn in vivo diabetic rat model and in vitro hyperglycemic-exposed retinal pigment epithelium (RPE) cell cultures were established to mimic early DR. Transmission electron microscopy and mRFP-GFP-LC3 adenovirus transfection were applied for autophagic flux analysis. MicroRNA (miR)-19a-3p, members of the phosphate and tensin homolog (PTEN)/Akt/mammalian target of rapamycin (mTOR) pathway, and the autophagy-related proteins light chain (LC)3II/I and p62 were detected. Annexin V, transwell, Cell Counting Kit-8, fluorescein isothiocyanate-dextran monolayer permeability assay, and transepithelial electrical resistance were performed to evaluate the effects of regulating autophagy on RPE cells under the DR condition.ResultsAutophagy was aberrantly activated in DR as evidenced by autophagosome accumulation. Further mechanistic experiments revealed that DR induced PTEN expression, thus inhibiting Akt/mTOR phosphorylation and stimulating aberrant autophagy and apoptosis. Notably, these events could be reversed by miR-19a-3p directly targeting PTEN. Downregulation of autophagy by miR-19a-3p overexpression, PTEN knockdown, or 3-methyladenine (3-MA) treatment inhibited autophagosome formation and thus effectively ameliorated hyperglycemia-induced RPE cell apoptosis, increased migration, inhibited viability, and enhanced monolayer permeability under the DR condition.ConclusionsOur findings suggest that upregulation of miR-19a-3p inhibits aberrant autophagy by directly targeting PTEN, thus protecting RPE cells against DR damage. miR-19a-3p may represent a novel therapeutic target for inducing protective autophagy in early DR. 相似文献
18.
Haobin Zhao Xiaoguang Xu Shuzhen Lei Dongyan Shao Chunmei Jiang Junling Shi Yawen Zhang Li Liu Shuzhen Lei Hui Sun Qingsheng Huang 《Journal of cellular physiology》2019,234(5):6414-6427
This study revealed that iturin A-like lipopeptides produced by Bacillus subtillis induced both paraptosis and apoptosis in heterogeneous human epithelial colorectal adenocarcinoma (Caco-2) cells. Autophagy was simultaneously induced in Caco-2 cells treated with iturin A-like lipopeptides at the early stage and inhibited at the later stage. A western blot analysis showed that the lipopeptides induced apoptosis in Caco-2 cells via a mitochondrial-dependent pathway, as indicated by upregulated expression of the apoptotic genes bax and bad and downregulated expression of the antiapoptotic gene bcl-2. The induction of paraptosis in Caco-2 cells was indicated by the occurrence of many cytoplasmic vacuoles accompanied by endoplasmic reticulum (ER) dilatation and mitochondrial swelling and dysfunction. ER stress also occurred with significant increases in reactive oxygen species and Ca2+ levels in cells. Autophagy was detected by a transmission electron microscopy analysis and by upregulated expression of LC3-II and downregulated expression of LC3-I. The inhibition of autophagy at the later stage was shown by upregulated expression of p62. This study revealed the capability of iturin A-like B. subtilis lipopeptides to simultaneously execute antitumor potential via multiple pathways. 相似文献
19.
Qi Chen Fei Yue Wenjiao Li Jing Zou Tao Xu Cheng Huang Ye Zhang Kun Song Guanqun Huang Guibin Xu Hai Huang Jun Li Leyuan Liu 《The Journal of biological chemistry》2015,290(43):26051-26058
Autophagy is a cellular process that controls and executes the turnover of dysfunctional organelles and misfolded or abnormally aggregated proteins. Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) activates the initiation of autophagy. Autophagosomes migrate along acetylated microtubules to fuse with lysosomes to execute the degradation of the engulfed substrates that usually bind with sequestosome 1 (SQSTM1, p62). Microtubule-associated protein 1 light chain 3 (LC3) traces the autophagy process by converting from the LC3-I to the LC3-II isoform and serves as a major marker of autophagy flux. Potassium bisperoxo(1,10-phenanthroline)oxovanadate (bpV(phen)) is an insulin mimic and a PTEN inhibitor and has the potential to treat different diseases. Here we show that bpV(phen) enhances the ubiquitination of p62, reduces the stability of p62, disrupts the interaction between p62 and histone deacetylase 6 (HDAC6), activates the deacetylase activity of HDAC6 on α-tubulin, and impairs stable acetylated microtubules. Microtubular destabilization leads to the blockade of autophagosome-lysosome fusion and accumulation of autophagosomes. Autophagy defects lead to oxidative stress and lysosomal rupture, which trigger different types of cell death, including apoptosis and pyroptosis. The consistent results from multiple systems, including mouse and different types of mammalian cells, are different from the predicted function of bpV(phen) as a PTEN inhibitor to activate autophagy flux. In addition, levels of p62 are reduced but not elevated when autophagosomal degradation is blocked, revealing a novel function of p62 in autophagy regulation. Therefore, it is necessary to pay attention to the roles of bpV(phen) in autophagy, apoptosis, and pyroptosis when it is developed as a drug. 相似文献
20.
Guoqian He Wenming Xu Linyan Tong Shuaishuai Li Shiceng Su Xiaodan Tan Changqing Li 《Apoptosis : an international journal on programmed cell death》2016,21(4):390-403
Autophagic (type II) cell death has been suggested to play pathogenetic roles in cerebral ischemia. Growth arrest and DNA damage response 45b (Gadd45b) has been shown to protect against rat brain ischemia injury through inhibiting apoptosis. However, the relationship between Gadd45b and autophagy in cerebral ischemia/reperfusion (I/R) injury remains uncertain. The aim of this study is to investigate the effect of Gadd45b on autophagy. We adopt the oxygen-glucose deprivation and reperfusion (OGD/R) model of rat primary cortex neurons, and lentivirus interference used to silence Gadd45b expression. Cell viability and injury assay were performed using CCK-8 and LDH kit. Autophagy activation was monitored by expression of ATG5, LC3, Beclin-1, ATG7 and ATG3. Neuron apoptosis was monitored by expression of Bcl-2, Bax, cleaved caspase3, p53 and TUNEL assay. Neuron neurites were assayed by double immunofluorescent labeling with Tuj1 and LC3B. Here, we demonstrated that the expression of Gadd45b was strongly up-regulated at 24 h after 3 h OGD treatment. ShRNA-Gadd45b increased the expression of autophagy related proteins, aggravated OGD/R-induced neuron cell apoptosis and neurites injury. ShRNA-Gadd45b co-treatment with autophagy inhibitor 3-methyladenine (3-MA) or Wortmannin partly inhibited the ratio of LC3II/LC3I, and slightly ameliorated neuron cell apoptosis under OGD/R. Furthermore, shRNA-Gadd45b inhibited the p-p38 level involved in autophagy, but increased the p-JNK level involved in apoptosis. ShRNA-Gadd45b co-treatment with p38 inhibitor obviously induced autophagy. ShRNA-Gadd45b co-treatment with JNK inhibitor alleviated neuron cell apoptosis. In conclusion, our data suggested that Gadd45b inhibited autophagy and apoptosis under OGD/R. Gadd45b may be a common regulatory protein to control autophagy and apoptosis. 相似文献