白藜芦醇通过TFEB调节细胞自噬的机制研究

目的研究白藜芦醇对HeLa细胞自噬的影响,探讨白藜芦醇通过转录因子TFEB调节自噬的可能机制。方法用0、12.5、25、50、100μmol/L白藜芦醇处理HeLa细胞后,CCK-8法检测细胞活性;Western blot检测凋亡相关蛋白Caspase-3、自噬相关蛋白LC3-Ⅱ和TFEB总蛋白水平以及TFEB在核提取液中的水平;荧光显微镜观察GFP-LC3融合蛋白在细胞内分布;荧光定量PCR检测TFEB及其靶基因mRNA水平。结果白藜芦醇处理24 h后HeLa细胞活性降低,激活型Caspase-3蛋白水平增加。白藜芦醇处理增加细胞LC3-Ⅱ蛋白水平,在12h达到高峰,且呈剂量依赖性变化,同时GFP-LC3荧光在细胞内呈点状聚集。白藜芦醇处理增加总细胞和核提取液中TFEB蛋白水平,并增加TFEB自身mRNA及其靶基因mRNA水平。结论白藜芦醇可能通过TFEB在转录水平调节细胞自噬。[营养学报,2019,41(4):374-378]     

孤核受体NR4A1通过线粒体机制调控细胞凋亡

孤核受体NR4A1参与调节细胞生存和凋亡。亚细胞定位研究发现,NR4A1定位于细胞核,表明其核因子的功能;在细胞质中也存在NR4A1,主要定位在线粒体,提示其通过线粒体机制调节细胞凋亡和自噬功能。在细胞核内,NR4A1作为一种促进细胞增殖的核因子发挥功能;在细胞质中,NR4A1与Bcl-2家族基因相互作用,通过直接或间接影响线粒体功能,导致细胞色素C释放入胞质,经线粒体相关的信号机制促进细胞凋亡,或在细胞自噬过程中发挥作用。现综述NR4A1通过线粒体参与细胞内的凋亡和自噬过程,探讨NR4A1在细胞质中的功能。     

线粒体自噬与卵巢功能

线粒体在决定卵母细胞发育能力和卵巢功能方面起重要作用。线粒体自噬是细胞选择性地清除多余或受损的线粒体,与维持细胞内线粒体稳态及细胞存活相关;但自噬被抑制或者被过度激活都可能影响细胞功能和细胞存活。当暴露于不良环境时,卵母细胞线粒体功能受损,诱发过量的线粒体自噬,导致卵母细胞质量下降。排卵后卵母细胞老化,氧化应激致线粒体损伤;应用抗氧化剂可以诱导线粒体自噬以清除受损的线粒体,降低氧化应激,改善卵母细胞的发育潜能。综述卵母细胞线粒体自噬与卵巢功能的关系,以及不良环境刺激和抗氧化剂对卵母细胞线粒体自噬的影响,为抗氧化剂应用于卵巢储备功能下降患者提高卵母细胞质量提供了理论依据。     

食物营养成分影响低氧所致线粒体自噬的研究进展

线粒体自噬是维持线粒体稳态的重要途径。在哺乳动物细胞，目前已知有两种线粒体自噬途径：受体依赖性和非依赖性途径，受体依赖性途径由BNIP3、BNIP3L/NIX、FUNDC1介导，受体非依赖性途径由PINK1-Parkin介导。低氧情况下，线粒体自噬途径激活，清除损伤的和功能紊乱的线粒体。研究表明，食物中的营养素（如叶酸、锌）和食物活性成分（如白藜芦醇、槲皮素、乔松素）等，可通过线粒体自噬途径发挥其抗低氧作用，减轻组织、细胞损伤。本文综述了食物营养成分调节低氧所致线粒体自噬的研究进展，旨在为研发基于食物营养成分的抗低氧营养制剂提供科学依据。[营养学报，2023,45(3):306-310]     

细胞铁死亡在镉毒性中的研究进展

铁死亡是近年新鉴定的一种程序性细胞死亡方式，具体机制主要涉及铁代谢、脂质代谢、线粒体及内质网功能紊乱等，进而参与多种疾病的发生发展。镉是一种广泛存在于自然环境中的有毒无机金属，也是公认的I类致癌物、表观遗传毒物和环境内分泌干扰物。目前有研究显示，镉能通过铁代谢紊乱、脂质代谢异常以及线粒体和内质网等细胞器功能失衡等诱导细胞发生铁死亡。本文归纳总结近年关于铁死亡参与镉毒性的最新研究进展，为镉毒性的机制探讨及防治策略的研究提供新的思路和方向。     

细胞自噬与脓毒症

自噬可分为3种类型：微自噬(microautophagy)、分子伴侣介导的自噬(chaperone mediated autophagy,CMA)和巨自噬(macroautophagy)。巨自噬(简称自噬autophagy)是一种基因调控的、高度保守的细胞降解过程,也是一种重要的自我平衡的过程,发生于所有真核细胞中［1-3］。在针对应激的过程中,自噬常常扮演着细胞应答的角色［4］。而且,自噬无论在先天免疫还是适应性免疫机制中均有着不可忽视的重要作用［2］。自噬与各种疾病的病理及生理过程广泛相关（例如感染、肿瘤、神经退行性疾病、心血管及肺部疾病等）,近期的研究［5-6］也表明,自噬在脓毒症中发挥一定的保护作用。本文从细胞病理学和分子生物学角度就细胞自噬在脓毒症发生发展中的作用作一综述,为寻找脓毒症治疗的新手段提供依据与线索。     

活性氧在1,4-苯醌诱导的线粒体自噬中的作用

目的探讨苯的代谢产物1,4-苯醌(1,4-BQ)能否活化PINK1/Parkin介导的线粒体自噬,以及活性氧(ROS)在线粒体自噬发生中的作用。方法以人早幼粒白血病细胞HL60为受试细胞,将其分为对照组、1,4-BQ组、N-乙酰半胱氨酸(NAC)组和1,4-BQ+NAC组。采用透射电镜观察细胞超微结构,采用蛋白免疫印迹法检测自噬蛋白LC3、PINK1和Parkin表达,采用DCFH-DA染色法测定胞内ROS含量。结果对照组细胞线粒体呈正常杆状结构,嵴线分明;1,4-BQ组可见呈椭圆肿胀变形的线粒体和包含双层膜性结构的线粒体自噬体。与对照组比较,1,4-BQ组的LC3-Ⅱ/LC3-Ⅰ比值、PINK1、Parkin蛋白表达和ROS含量均增加(P0.05);1,4-BQ+NAC组的LC3-Ⅱ/LC3-Ⅰ比值、PINK1、Parkin蛋白表达和ROS含量均低于1,4-BQ组(P0.05)。结论 1,4-BQ可诱导PINK1/Parkin途径的线粒体自噬,且ROS在诱导的线粒体自噬中起重要作用。     

围脂滴蛋白生物学功能及其基因多态性与肥胖的关系

围脂滴蛋白(perilipin1, PLIN1)是一种重要脂滴表面蛋白,在体内能量平衡和脂质代谢中发挥着关键作用,其遗传变异与人类疾病密切相关。本文阐述了PLIN1基因及其蛋白的结构定位和表达分布,PLIN1在脂质代谢、自噬和炎症反应中的作用以及潜在的调控机制,PLIN1基因的单核苷酸多态性位点与肥胖的关系。     

胰岛素抵抗与血管内皮细胞功能障碍研究进展

胰岛素抵抗 (IR)不仅是代谢性疾病和心血管疾病的重要危险因素 ,在动脉粥样硬化 (AS)的发生、发展中也具有重要作用 ,但IR是否为其根本缺陷仍有争议[1 ] 。近年来 ,IR与血管内皮细胞 (EC)功能关系日益受到重视 ,并成为揭示IR/代谢综合征 (MS)与大血管病变本质的一条新的途径 ,对进一步研究心血管病和高血压、糖尿病 (DM)及血脂紊乱等代谢相关性疾病的发病机制及防治有着重大意义。本文就近几年该领域的有关进展作以下综述。1　血管EC功能及影响因素EC具有多重生物学功能 ,包括主动控制血管张力、管理血液流动 ,调节单核细胞与EC的…     

沉默信息调节因子3蛋白对线粒体代谢和凋亡调节的研究进展

沉默信息调节因子3(sirt3)是线粒体烟碱腺嘌呤二核苷酸(NAD)依赖的去乙酰化蛋白,是调节线粒体代谢关键酶,可维持细胞内稳态平衡,在线粒体氧化代谢、能量代谢、信号调节和细胞凋亡等活动中发挥重要作用。sirt3是重要的凋亡调节因子,调节线粒体生物学效应和氧化应激水平,抵抗神经元细胞凋亡,其缺失可引起线粒体代谢异常和细胞损伤,甚至引起细胞凋亡。笔者综述了sirt3在线粒体三羧酸循环(TCA)、脂肪酸氧化等代谢活动和细胞凋亡中的重要作用,阐明sirt3可以维持线粒体的正常代谢活动,抵抗细胞凋亡,为肿瘤等疾病的研究提供重要靶点。     

血管生成素样蛋白与胰岛素抵抗和糖代谢的关系及在多囊卵巢综合征中的作用

多囊卵巢综合征(polycystic ovary syndrome,PCOS)是育龄期女性最常见的内分泌及代谢性疾病之一,PCOS患者发生心血管疾病和2型糖尿病的风险增加.越来越多的研究支持胰岛素抵抗(insulin resistance,IR)是PCOS重要的病理机制之一.血管生成素样蛋白(angiopoietin-...     

促凋亡基因Nix的特性及对心肌疾病的作用

细胞凋亡是机体维持自身稳定的一种基本生理机制,是有许多基因产物及细胞因子参与的一种有序的细胞自我消亡形式。心肌细胞凋亡发生的主要机制是Bcl-2家族参与了细胞凋亡的"线粒体途径"。Bcl-2家族在线粒体凋亡通路中发挥了重要的作用,Nix蛋白是Bcl-2家族中BH3-only亚家族的一个促凋亡蛋白,其参与线粒体自噬、在低氧条件下能诱导细胞凋亡;Nix基因也可能是一个肿瘤抑制基因。近年研究发现其在诱导心肌细胞凋亡、坏死过程中发挥重要的作用。通过简述Nix特性、诱导细胞凋亡机制及通过对Nix在心肌疾病中的研究,来了解Nix在心肌疾病中的作用。     

Ameliorative Effects of Gut Microbial Metabolite Urolithin A on Pancreatic Diseases

Urolithin A (Uro A) is a dietary metabolite of the intestinal microbiota following the ingestion of plant-based food ingredients ellagitannins and ellagic acid in mammals. Accumulating studies have reported its multiple potential health benefits in a broad range of diseases, including cardiovascular disease, cancer, cognitive impairment, and diabetes. In particular, Uro A is safe via direct oral administration and is non-genotoxic. The pancreas plays a central role in regulating energy consumption and metabolism by secreting digestive enzymes and hormones. Numerous pathophysiological factors, such as inflammation, deficits of mitophagy, and endoplasmic reticulum stress, can negatively affect the pancreas, leading to pancreatic diseases, including pancreatitis, pancreatic cancer, and diabetes mellitus. Recent studies showed that Uro A activates autophagy and inhibits endoplasmic reticulum stress in the pancreas, thus decreasing oxidative stress, inflammation, and apoptosis. In this review, we summarize the knowledge of Uro A metabolism and biological activity in the gut, as well as the pathological features and mechanisms of common pancreatic diseases. Importantly, we focus on the potential activities of Uro A and the underlying mechanisms in ameliorating various pancreatic diseases via inhibiting inflammatory signaling pathways, activating autophagy, maintaining the mitochondrial function, and improving the immune microenvironment. It might present a novel nutritional strategy for the intervention and prevention of pancreatic diseases.     

线粒体能量代谢在低氧诱导相关疾病中的研究进展

线粒体作为氧化代谢的主要场所,在低氧损伤中首当其冲。低氧诱导的线粒体能量代谢障碍与多种疾病相关,如心肌缺血/再灌注损伤、癌症等,探究线粒体能量代谢在低氧诱导的有关疾病中的作用对于临床疾病的治疗及特殊环境医学、航空航天医学等的发展都具有重要意义。本文将从线粒体结构及功能、低氧诱导线粒体能量代谢障碍及其与疾病发生发展的关系三个方面进行阐述。     

环状RNA与妊娠相关疾病

环状RNA（circular RNA,circRNA）由反向剪接的信使RNA前体产生的非编码RNA组成,在反向剪接过程中,下游剪接供体位点与上游剪接受体位点共价连接。circRNA广泛存在于各类真核生物细胞和有机体中,结构稳定。随着高通量测序等分子生物技术的快速发展,circRNA的生物学作用得以被认识,并成为生物学研究领域的新方向。近年研究表明,正常妊娠与病理妊娠相比较,在其胎盘组织及母体血浆中circRNA的表达存在显著差异,circRNA通过调控滋养细胞上皮间质转化、胎盘微血管形成、妊娠期葡萄糖和脂质代谢稳态和介导母胎界面炎症微环境等过程,影响妊娠期疾病的发生发展。circRNA与微小RNA、RNA结合蛋白的相互作用也可调节胎盘自噬及母体脂肪代谢。综述circRNA的生物学作用及其在妊娠相关疾病中的研究进展。     

Flazin as a Lipid Droplet Regulator against Lipid Disorders

Lipid disorders are closely related to numerous metabolic diseases, and lipid droplets (LDs) have been considered as a new target for regulating lipid metabolism. Dietary intervention and nutraceuticals provide safe and long-term beneficial effects for treating metabolic diseases. Flazin is a diet-derived bioactive constituent mainly existing in fermented foods, of which the lipid metabolism improvement function has not been studied. In this study, the effect of flazin on lipid regulation at both cell level and organelle level was investigated. Lipidomic profiling showed that flazin significantly decreased cellular triglyceride (TG) by 12.0–22.4% compared with modeling groups and improved the TG and free fatty acid profile. LD staining revealed that flazin efficiently reduced both cellular neutral lipid content by 17.4–53.9% and LD size by 10.0–35.3%. Furthermore, nanoelectrospray ionization mass spectrometry analysis proved that flazin exhibited a preferential suppression of LD TG and regulated LD morphology, including a size decrease and surface property improvement. An evaluation of related gene expression suggested the mechanism to be lipolysis promotion and lipogenesis inhibition. These findings indicated that flazin might be an LD regulator for reversing lipid metabolism disturbance. Moreover, the strategy proposed in this study may contribute to developing other nutraceuticals for treating lipid disorder-related metabolic diseases.     

Metabolome Characteristics of Liver Autophagy Deficiency under Starvation Conditions in Infancy

The liver function is essential for metabolism, detoxification, and bile synthesis, even in the neonatal period. Autophagy plays significance roles in THE adult liver, whereas the role of liver autophagy in the early neonatal period largely remains unclear. To clarify the importance of liver autophagy in the neonatal starvation period, we generated liver-specific autophagy-deficient (Atg5^flox/flox; Albumin-Cre) mice and investigated under starvation conditions comparing with control (Atg5^flox/+; Albumin-Cre) mice, focusing on serum metabolites and liver histopathology. As a result, autophagy in the liver was found to unessential for the survival under postnatal starvation. A metabolomics analysis of serum metabolites by gas chromatography-tandem mass spectrometry showed a significant difference between the groups, especially after 12-h starvation, suggesting the synergistical adaption of metabolic pathways, such as the “malate-aspartate shuttle”, “aspartate metabolism”, “urea cycle”, and “glycine and serine metabolism”. Liver-specific autophagy-deficiency under postnatal starvation conditions can cause a characteristic metabolic alteration suggesting a change of the mitochondrial function. Neonates seemed to maintain ketone production under starvation conditions, even in the autophagy-deficient liver, through a change in the mitochondrial function, which may be an adaptive mechanism for avoiding fatal starvation.     

Role of autophagy in the pathogenesis of liver diseases

Autophagy is a self-digestion process that plays an important role in the development, differentiation and homeostasis of cells, helping their survival during starvation and hypoxia. Accumulated mutant proteins in the endoplasmic reticulum can be degraded by autophagy in alpha-1 antitrypsin deficiency. Hepatitis C and B virus may exploit the autophagy pathway to escape the innate immune response and to promote their own replication. Autophagy is decreased in response to chronic alcohol consumption, likely due to a decrease in 5'-adenosine monophosphate-activated protein kinase, increase in mTOR activity and due to an alteration in vesicle transport in hepatocytes. In obesity and alcoholic liver disease the decreased function of autophagy causes formation of Mallory-Denk bodies and cell death. The deficient autophagy can contribute to liver steatosis, to endoplasmic reticulum stress, and to progression of liver disease. Autophagy defect in hepatocellular carcinoma suggests that it can serve a tumor-suppressor function. The autophagy protein Beclin-1 levels have prognostic significance in liver tumors. Understanding of the molecular mechanism and the role of autophagy may lead to more effective therapeutic strategies in liver diseases in the future.     

Reduction of oocyte lipid droplets and meiotic failure due to biotin deficiency was not rescued by restoring the biotin nutritional status

BACKGROUND/OBJECTIVESOocyte lipid droplets play a crucial role in meiosis and embryo development. Biotin is associated with fatty acid synthesis and is the coenzyme for acetyl-CoA carboxylase (ACC). The effects of a biotin deficiency on the oocyte lipid metabolism remain unknown. This study examined the effects of a biotin deficiency and its replenishment on murine 1) oocyte lipid droplet levels, 2) ovary lipid metabolism, and 3) oocyte meiosis.MATERIALS/METHODSMice were divided into 3 groups: control, biotin deficient (BD), and recovery groups. The control and BD groups were fed a control diet or BD diet (0.004 or 0 g biotin/kg), respectively. The recovery group mice were fed a BD diet until day 21, and were then fed the control diet from days 22 to 64. This study then quantified the oocyte lipid droplet levels, assessed the oocyte mitochondrial function, and examined the ability of oocytes to undergo meiosis. Ovarian phosphorylated ACC (p-ACC), lipogenesis, β-oxidation, and ATP production-related genes were evaluated.RESULTSThe BD group showed a decrease in lipid droplets and mitochondrial membrane potential and increased p-ACC levels. In the recovery group, the hepatic biotin concentration, ovarian p-ACC levels, and mitochondrial membrane potential were restored to the control group levels. On the other hand, the quantity of lipid droplets in the recovery group was not restored to the control levels. Furthermore, the percentage of oocytes with meiotic abnormalities was higher in the recovery group than in the control group.CONCLUSIONSA biotin deficiency reduced the oocyte lipid droplet levels by downregulating lipogenesis. The decreased lipid droplets and increased oocyte meiosis failure were not fully restored, even though the biotin nutrition status and gene expression of lipid metabolism was resumed. These results suggest that a biotin deficiency remains robust and can be long-lasting. Biotin might play a crucial role in maintaining the oocyte quality.