高糖通过调控FBW7表达影响自噬的研究

目的探索高糖调控FBW7表达对自噬的影响。方法不同浓度(10、20和30 mmol/L)葡萄糖刺激小鼠肾小球系膜细胞后,采用Western blot检测泛素连接酶FBW7、哺乳动物雷帕霉素靶蛋白(mTOR)、磷酸化的哺乳动物雷帕霉素靶蛋白(p-mTOR)的表达水平,以及LC3-Ⅱ/Ⅰ比值,采用RT-PCR进一步检测FBW7的mRNA水平;采用自噬双标腺病毒检测自噬溶酶体。采用基因过表达技术过表达FBW7并检测相关蛋白水平及自噬水平。结果葡萄糖浓度越高,FBW7、LC3-Ⅱ/Ⅰ比值和自噬溶酶体水平越低,mTOR、p-mTOR的表达水平越高。基因过表达FBW7可抑制mTOR和p-mTOR(Ser2448)蛋白表达,增加LC3-Ⅱ/Ⅰ比值及自噬溶酶体数量(P0.05)。结论高糖下调FBW7表达激活mTOR信号通路,引起小鼠肾系膜细胞自噬水平的降低。     

溶酶体组织蛋白酶与自噬在心肌重构中的作用研究

越来越多的证据表明,心肌细胞自噬失调与心肌肥厚进展有关,然而自噬在心肌重构中的作用仍然是一个有争议的问题[14].自噬过程由多种蛋白质控制,它由自噬体的形成启动,自噬体是一种双膜囊泡,与晚期内体和溶酶体融合,促进蛋白的降解.在溶酶体蛋白中,组织蛋白酶(cathepsins,Cts)是激活自噬所需最丰富的蛋白酶[5].自...     

苯并(a)芘通过降低突触融合蛋白17和溶酶体关联膜蛋白2表达阻抑人脐静脉内皮细胞自噬流

目的 研究苯并(a)芘(BaP)影响人脐静脉内皮细胞(HUVEC)自噬的机制。方法 HUVEC经BaP(2.5、5、10 μmol/L)处理24 h后,分别采用间接免疫荧光法、Western blot、吖啶橙染色和单丹磺酰尸胺染色等技术方法,检测自噬体及其内容物降解、目标蛋白微管相关蛋白1轻链3(LC3)、选择性自噬接头蛋白p62、Beclin-1、自噬相关蛋白5(Atg5)、Atg7、Atg12、组织蛋白酶B(CTSB)、组织蛋白酶D(CTSD)、突触融合蛋白17(STX17)、溶酶体关联膜蛋白2(LAMP2)表达、溶酶体数量与功能,及相关上游关键调控蛋白丝氨酸-苏氨酸蛋白激酶(Akt)、细胞外调节蛋白激酶(ERK)、转录因子EB(TFEB)磷酸化水平。结果 BaP暴露组HUVEC内,检测结果显示:(1)LC3 puncta水平、LC3Ⅱ/LC3Ⅰ比率增加,自噬起始关键蛋白(Beclin-1、Atg5、Atg7、Atg12)表达升高,Akt蛋白磷酸化则明显降低;(2)p62 puncta和p62蛋白水平明显升高;(3)溶酶体数量增加,并伴随着溶酶体特征性水解酶(CTSB、CTSD)表达升高,相应地ERK、TFEB磷酸化水平增加;(4)调控自噬体与溶酶体融合的关键蛋白STX17与LAMP2降低。结论 BaP通过降低STX17与LAMP2表达水平,阻抑了HUVEC正常的自噬流。     

阿尔茨海默病与自噬

<正>阿尔茨海默病(AD)是一种普遍流行于老年群体的以记忆、行为、学习功能障碍为主要特征的神经退行性疾病,占全部老年期痴呆的80%左右[1]。自噬(Autophagy)是一种正常的、调节性的回收衰老细胞组分、清除结构或功能异常细胞器或蛋白聚合物的细胞生理过程[2,3]。自噬分为三种方式:有自噬体形成的大自噬、溶酶体膜内陷发生的小自噬、针对错误结合蛋白的分子伴侣介导自噬(CMA)(下文中"自噬"均指"大自     

细胞自噬与肝炎病毒感染的相关性研究

自噬(autophagy)又称细胞的自体溶解,是指隔离膜包裹胞浆蛋白和细胞器形成自噬体(autophagosome),然后与溶酶体融合成自噬溶酶体(autolysosome)并在其中降解的过程。自噬现象普遍存在于大部分真核细胞中,通过对细胞内变性蛋白或受损细胞器进行降解,以维持细胞内物质循环及代谢调节的稳定,在细胞生长、分化、功能执行、自我更新、衰老及死亡中发挥着重要调控功能。近期有大量研究表明,细胞自噬与肝炎病毒感染的发生、发展及预后有相关性。本文就自噬发生、演变过程中的分子机制及其与肝炎病毒感染的关系作一概述。     

自噬及其在急性胰腺炎中的作用

自噬(autophagy)是一种溶酶体参与的、复杂的分解细胞内蛋白和亚细胞结构的过程.通常,细胞处于"饥饿"或其他应激的情况下,通过降解细胞内蛋白和细胞器为细胞的基本代谢提供能量.基因分析发现,调控自噬过程的基因在进化中高度保守,从酵母、果蝇到脊椎动物和人都可以找到参与自噬的同源基因;并且这些基因在胚胎发育和肿瘤发生中发挥作用.形态上,自噬以细胞内形成空泡样结构为特点,将蛋白、亚细胞结构包裹,或直接与溶酶体结合而降解.近来的研究表明,自噬功能的异常与许多疾病的发生与发展有关.     

自噬和自噬性细胞死亡与肿瘤的关系及研究进展

自噬是指隔离膜包裹细胞质和(或)细胞器形成自噬体,然后与溶酶体融合成自噬溶酶体并在其中降解的过程。自噬性细胞死亡的特征为细胞质中出现大量的自噬体和自噬溶酶体。Beclinl、PIEN可能是自噬相关基因,自噬、自噬性细胞死亡在肿瘤发生、发展中可能发挥重要的作用。     

活性维生素D3改善高糖环境下肾小管上皮细胞自噬溶酶体通路的研究

目的探讨活性维生素D3对高糖环境下肾小管上皮细胞自噬溶酶体通路的影响和机制。方法将人近端小管上皮细胞(HK-2)细胞分为正常对照(Con)组、甘露醇组(Man)、高糖组(HG)、高糖+活性维生素D3组(HG+VD)。Western blot法检测自噬小体(LC3II)、自噬底物(P62)、溶酶体相关膜蛋白1(LAMP1)和组织蛋白酶B(CTSB)、维生素D受体(VDR)及转录因子EB(TFEB)蛋白表达。结果与Con组比较,HG组LC3II、LAMP1、CTSB、VDR、TFEB蛋白表达降低,P62蛋白表达升高(P0.05)。与HG组比较,HG+VD组LC3II、LAMP1、CTSB、VDR、TFEB蛋白表达升高,P62表达降低(P0.05)。结论活性维生素D3可改善高糖环境下肾小管上皮细胞自噬溶酶体通路,其机制可能与调控TFEB相关。     

自噬与肝脏脂代谢

细胞自噬是利用溶酶体降解受损的细胞器、未折叠蛋白来维持细胞内稳态,在机体生长、发育和衰老中均起重要作用.研究表明,自噬可能与肝脏脂肪合成及分解相关.固醇调节元件结合蛋白通路、转录因子、激素与营养因素可能会影响自噬,从而改变脂代谢.     

自噬与非酒精性脂肪性肝病调控相关因子的关系

非酒精性脂肪性肝病(NAFLD)是一种常见疾病,病理表现为肝细胞内脂肪滴大量蓄积。NAFLD不仅成因复杂,还可诱发心血管疾病、糖尿病等,然而目前尚无有效的治疗手段和专门的治疗药物。自噬在真核生物中普遍存在,具有维持细胞内稳态的作用。自噬选择性降解细胞中脂质的机制称为脂噬,该机制为缓解因脂质蓄积引起的疾病提供了新思路。从NAFLD发生发展、脂肪滴降解过程、肝脏炎症和纤维化进展相关因子入手,探讨了自噬与NAFLD的相关性。这可能为从自噬入手治疗NAFLD提供理论基础,并为相关药物的研发提供作用靶点。     

自噬与病毒性心肌炎关系研究进展

自噬（autophagy）是细胞依赖溶酶体对胞内蛋白质和受损细胞器进行降解的一条重要途径。细胞自噬受各种因子的精密调节,是细胞清除损伤物质和维持细胞稳态的重要调节方式,与心血管疾病、肿瘤和神经退行性疾病发生密切相关［1］。近几年有文献报道病毒性心肌炎中存在细胞自噬现象［2~4］,结合作者前期试验在小鼠病毒性心肌炎模型中亦观察到细胞自噬现象,因此本文就自噬与病毒性心肌炎的关系进行综述。     

Hepatic autophagy fluctuates during the development of non-alcoholic fatty liver disease

Introduction and objectivesAutophagy has emerged as a critical regulatory pathway in non-alcoholic fatty liver disease (NAFLD). However, the variability of hepatic autophagy during NAFLD development remains controversial. This study aimed to elucidate the dynamics of hepatic autophagy and its underlying mechanism during NAFLD development both in vivo and in vitro.Materials and methodsAutophagy markers were evaluated in the livers of mice fed a high fat diet or a methionine-choline-deficient diet and in HepG2 cells treated with palmitic acid (PA) by western blotting. Intrahepatic and intracellular triacylglycerol levels were assessed using biochemical quantification and lipid staining. Autophagic flux was monitored using an LC3 turnover assay and tandem mRFP-GFP-LC3 fluorescence analysis.ResultsHepatic autophagy was enhanced in early stages but blocked at later stages of NAFLD development both in vivo and in vitro. Analysis of autophagic flux revealed that both autophagic synthesis and degradation were initially activated and progressively inhibited afterwards. The activation of mammalian target of rapamycin complex 1 (mTORC1), a central regulator of autophagy, was found to be negatively correlated with autophagic synthesis; moreover, pharmacological inhibition of mTORC1 by rapamycin alleviated hepatic steatosis through recovery of autophagic flux in hepatocytes with prolonged PA treatment.ConclusionsHepatic autophagy fluctuates during the development of NAFLD in which mTORC1 signalling plays a critical regulatory role, suggesting a therapeutic potential of autophagy modulation by targeting the mTORC1 signalling pathway in NAFLD.     

Traditional Chinese herbal extracts inducing autophagy as a novel approach in therapy of nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease(NAFLD) is one of the leading causes of chronic liver diseases around the world due to the modern sedentary and food-abundant lifestyle, which is characterized by excessive fat accumulation in the liver related with causes other than alcohol abuse. It is widely acknowledged that insulin resistance, dysfunctional lipid metabolism, endoplasmic reticulum stress, oxidative stress, inflammation, and apoptosis/necrosis may all contribute to NAFLD. Autophagy is a protective self-digestion of intracellular organelles, including lipid droplets(lipophagy), in response to stress to maintain homeostasis. Lipophagy is another pathway for lipid degradation besides lipolysis. It is reported that impaired autophagy also contributes to NAFLD. Some studies have suggested that the histological characteristics of NAFLD(steatosis, lobular inflammation, and peri-sinusoid fibrosis) might be improved by treatment with traditional Chinese herbal extracts, while autophagy may be induced. This review will provide insights into the characteristics of autophagy in NAFLD and the related role/mechanisms of autophagy induced by traditional Chinese herbal extracts such as resveratrol, Lycium barbarum polysaccharides, dioscin, bergamot polyphenol fraction, capsaicin, and garlic-derived S-allylmercaptocysteine, which may inhibit the progression of NAFLD. Regulation of autophagy/lipophagy with traditional Chinese herbal extracts may be a novel approach for treating NAFLD, and the molecular mechanisms should be elucidated further in the near future.     

Role and mechanisms of autophagy in acetaminophen‐induced liver injury

Acetaminophen (APAP) overdose is the most frequent cause of acute liver failure in the USA and many other countries. Although the metabolism and pathogenesis of APAP has been extensively investigated for decades, the mechanisms by which APAP induces liver injury are incompletely known, which hampers the development of effective therapeutic approaches to tackle this important clinical problem. Autophagy is a highly conserved intracellular degradation pathway, which aims at recycling cellular components and damaged organelles in response to adverse environmental conditions and stresses as a survival mechanism. There is accumulating evidence indicating that autophagy is activated in response to APAP overdose in specific liver zone areas, and pharmacological activation of autophagy protects against APAP‐induced liver injury. Increasing evidence also suggests that hepatic autophagy is impaired in nonalcoholic fatty livers (NAFLD), and NAFLD patients are more susceptible to APAP‐induced liver injury. Here, we summarized the current progress on the role and mechanisms of autophagy in protecting against APAP‐induced liver injury.     

β-cell autophagy: A novel mechanism regulating β-cell function and mass: Lessons from β-cell-specific Atg7-deficient mice

Autophagy is a membrane-trafficking mechanism that delivers cytoplasmic components into the lysosome to form autophagic vacuoles for bulk protein degradation. While previous studies have reported enhanced autophagosome formation in pancreatic β-cells under some pathophysiological conditions, the role of autophagy remains largely unknown. We have reported that low-level constitutive basal autophagy was observed in β-cells of C57BL/6 mice fed standard diet; however, autophagy was markedly up-regulated in mice fed high-fat diet. Free fatty acids (FFAs), which can cause peripheral insulin resistance associated with diabetes, induced autophagy in β-cells. Genetic inactivation of autophagic machinery in β-cells resulted in reduced glucose-stimuated insulin secretion with progressive intracellular accumulation of ubiquitinated proteins and deformed mitochondria. These results suggest that the degradation of cellular components by basal autophagy is essential for the maintenance of normal architecture and function of β-cells. We will also discuss the role of inductive autophagy as a crucial element of stress responses to protect β-cells, which supports compensatory β-cell growth in the presence of insulin resistance.     

β-cell autophagy: A novel mechanism regulating β-cell function and mass- Lessons from β-cell-specific Atg7-deficient mice

Autophagy is a membrane-trafficking mechanism that delivers cytoplasmic components into the lysosome to form autophagic vacuoles for bulk protein degradation. While previous studies have reported enhanced autophagosome formation in pancreatic β-cells under some pathophysiological conditions, the role of autophagy remains largely unknown. We have reported that low-level constitutive basal autophagy was observed in β-cells of C57BL/6 mice fed standard diet; however, autophagy was markedly up-regulated in mice fed high-fat diet. Free fatty acids (FFAs), which can cause peripheral insulin resistance associated with diabetes, induced autophagy in β-cells. Genetic inactivation of autophagic machinery in β-cells resulted in reduced glucose-stimuated insulin secretion with progressive intracellular accumulation of ubiquitinated proteins and deformed mitochondria. These results suggest that the degradation of cellular components by basal autophagy is essential for the maintenance of normal architecture and function of β-cells. We will also discuss the role of inductive autophagy as a crucial element of stress responses to protect β-cells, which supports compensatory β-cell growth in the presence of insulin resistance.     

寄生虫感染与宿主细胞自噬相互作用研究进展

自噬是一种真核细胞特有的生命现象,是一种保守的细胞内降解系统。通常所说的自噬是通过双层膜包裹细胞质成分形成自噬体,随后与溶酶体融合,从而降解细胞自身物质的过程。自噬可以由饥饿诱导,也可以由包括寄生虫在内的各种病原体所诱导。当机体感染胞内寄生虫时,宿主细胞可以通过自噬清除寄生虫。然而,寄生虫也进化出自身防御机制,能够利用宿主细胞自噬促进自身发育生长。本文综述了目前国内外关于寄生虫感染与宿主细胞自噬相互影响的研究进展,深入探讨自噬作用对防治寄生虫感染和抗虫药物研发具有重要意义。     

Autophagy in immune cell regulation and dysregulation

Autophagy is an ancient pathway required for cell and tissue homeostasis and differentiation. Initially thought to be a process leading to cell death, autophagy is currently viewed as a beneficial catabolic process that promotes cell survival under starvation conditions by sequestering components of the cytoplasm, including misfolded proteins, protein aggregates, and damaged organelles, and targeting them for lysosome-mediated degradation. In this way, autophagy plays a role in maintaining a balance between degradation and recycling of cellular material. The importance of autophagy is underscored by the fact that malfunctioning of this pathway results in neurodegeneration, cancer, susceptibility to microbial infection, and premature aging. Autophagy occurs in almost all cell types, including immune cells. Recent advances in the field suggest that autophagy plays a central role in regulating the immune system at multiple levels. In this review, we focus on recent developments in the area of autophagy-mediated modulation of immune responses.     

Mitochondrial Fission and Autophagy in the Normal and Diseased Heart

Sustained hypertension promotes structural, functional and metabolic remodeling of cardiomyocyte mitochondria. As long-lived, postmitotic cells, cardiomyocytes turn over mitochondria continuously to compensate for changes in energy demands and to remove damaged organelles. This process involves fusion and fission of existing mitochondria to generate new organelles and separate old ones for degradation via autophagy. Autophagy is a lysosome-dependent proteolytic pathway capable of processing cellular components, including organelles and protein aggregates. Autophagy can be either nonselective or selective and contributes to remodeling of the myocardium under stress. Fission of mitochondria, loss of membrane potential, and ubiquitination are emerging as critical steps that direct selective autophagic degradation of mitochondria. This review discusses the molecular mechanisms controlling mitochondrial dynamics, including fission, fusion, transport, and degradation. Furthermore, it examines recent studies revealing the importance of these processes in normal and diseased heart.     

自噬在心肌缺血再灌注中作用的研究进展

自噬是指细胞内的自身物质被溶酶体所降解的过程,为普遍存在的生命现象,是细胞处于饥饿状态时的一种自我保护机制。既往研究表明,在心肌缺血再灌注过程中,自噬被诱导激活,自噬体明显增多。自噬在缺血再灌注中的作用表现出双面性,缺血期主要发挥保护作用,但再灌注时期自噬过度激活则表现出损伤作用,可导致自噬性细胞死亡。自噬具体是如何被激活,怎样发挥其影响作用,至今尚无清楚的答案。本文就自噬在心肌缺血再灌注中作用的研究进展进行综述。