Mitochondria as a Platform for Dictating the Cell Fate of Cultured Human Corneal Endothelial Cells

PurposeAiming to clarify the role of mitochondria in cell fate decision of cultured human corneal endothelial cell (cHCEC) subpopulations.MethodsThe mitochondrial respiratory ability were examined with Mito stress and Mito fuel flex test assays using an extracellular flux analyzer (XFe24; Agilent Technologies; Santa Clara, CA) for human corneal endothelium tissues, mature cHCECs and a variety of cell state transitioned cHCECs. Tricarboxylic acid cycle and acetyl-coenzyme A–related enzymes was analyzed by proteomics for cell lysates using liquid chromatography–tandem mass spectrometry for cHCEC subpopulations.ResultsThe maximum oxygen consumption rate was found to become stable depending on the maturation of cHCECs. In the Mito stress tests, culture supplements, epidermal growth factor, SB203580, and SB431543 significantly repressed oxygen consumption rate, whereas a Rho-associated protein kinase inhibitor Y-27632 increased. Tricarboxylic acid cycle and mitochondria acetyl-coenzyme A–related enzymes were selectively upregulated in mature cHCECs, but not in cell state transitioned cHCECs. The maximum oxygen consumption rate was found to be higher in healthy human corneal endothelium tissues than those with deeply reduced cell density. An upregulated tricarboxylic acid cycle was linked with metabolic rewiring converting cHCECs to acquire the mitochondria-dependent oxidative phenotype.ConclusionsMitochondrial metabolic intermediates and energy metabolism are tightly linked to the endothelial cell fate and function. These findings will help us to standardize a protocol for endothelial cell injection.     

下调乙酰辅酶A合成酶2通过诱导自噬抑制非小细胞肺癌细胞增殖

目的：探讨乙酰辅酶A合成酶2（ACSS2）在非小细胞肺癌（NSCLC）细胞中的表达及其对细胞增殖、侵袭的调控机制。方法：采用蛋白质印迹（Western blot）实验检测并分析NSCLC细胞系A549和H1299与人成纤维细胞HFF-1中ACSS2表达的差异。利用慢病毒在NSCLC细胞系中构建ACSS2敲低（ACSS2 KD组）和对照细胞系（NC组）。采用MTT实验及细胞克隆形成实验分析ACSS2 对NSCLC细胞增殖的影响。采用划痕实验和Transwell实验分析ACSS2对NSCLC细胞的迁移和侵袭能力的影响。Western blot及免疫荧光实验分析敲低ACSS2 对细胞自噬的影响。结果：与人成纤维细胞HFF-1相比,NSCLC细胞中ACSS2 的蛋白表达水平明显升高（P ＜0.05）。与NC组相比,ACSS2 KD组细胞增殖能力和细胞活力显著降低,ACSS2 KD组细胞的迁移和侵袭能力均明显降低（均P ＜0.01）。Western blot和免疫荧光实验显示,敲低ACSS2 细胞自噬活性明显增加,自噬小体增多（P ＜0.01）。但是,敲低ACSS2几乎不影响caspase3和caspase8的蛋白表达水平（P ＞0.05）。ACSS2 shRNA+Beclin1/Atg7-shRNA共转染A549细胞（ACSS2+Beclin1/Atg7 KD组）,结果显示与ACSS2KD组比,ACSS2 KD+Beclin1/Atg7 KD组细胞增殖能力有所增强,克隆形成数目明显增多（P ＜0.05）。结论：ACSS2在NSCLC细胞中高表达,促进细胞的增殖、侵袭。下调ACSS2可诱导NSCLC细胞发生自噬性细胞死亡,抑制细胞增殖。     

Role of AMPK in pancreatic beta cell function

Pharmacological activation of AMP activated kinase (AMPK) by metformin has proven to be a beneficial therapeutic approach for the treatment of type II diabetes. Despite improved glucose regulation achieved by administration of small molecule activators of AMPK, the potential negative impact of enhanced AMPK activity on insulin secretion by the pancreatic beta cell is an important consideration. In this review, we discuss our current understanding of the role of AMPK in central functions of the pancreatic beta cell, including glucose-stimulated insulin secretion (GSIS), proliferation, and survival. In addition we discuss the controversy surrounding the role of AMPK in insulin secretion, underscoring the merits and caveats of methods used to date.     

Herbal medicines for the prevention of alcoholic liver disease: A review

Ethnopharmacological relevance

Long-term excess alcohol exposure leads to alcoholic liver disease (ALD)—a global health problem without effective therapeutic approach. ALD is increasingly considered as a complex and multifaceted pathological process, involving oxidative stress, inflammation and excessive fatty acid synthesis. Over the past decade, herbal medicines have attracted much attention as potential therapeutic agents in the prevention and treatment of ALD, due to their multiple targets and less toxic side effects. Several herbs, such as Cnidium monnieri (L.) Cusson (Apiaceae), Curcuma longa L. (Zingiberaceae) and Pueraria lobata (Willd.) Ohwi (Leguminosae), etc., have been shown to be quite effective and are being widely used in China today for the treatment of ALD when used alone or in combination.

Aim of the review

To review current available knowledge on herbal medicines used to prevent or treat ALD and their underlying mechanisms.

Materials and methods

We used the pre-set searching syntax and inclusion criteria to retrieve available published literature from PUBMED and Web of Science databases, all herbal medicines and their active compounds tested on ALD induced by both acute and chronic alcohol ingestion were included.

Results

A total of 40 experimental studies involving 34 herbal medicines and (or) active compounds were retrieved and reviewed. We found that all reported extracts and individual compounds from herbal medicines/natural plants could be beneficial to ALD, which might be attributed to regulate multiple critical targets involved in the pathways of oxidation, inflammation and lipid metabolism.

Conclusions

Screening chemical candidate from herbal medicine might be a promising approach to drug discovery for the prevention or treatment of ALD. However, further studies remain to be done on the systematic assessment of herbal medicines against ALD and the underlying mechanisms, as well as their quality control studies.     

乙酰辅酶A羧化酶抑制剂的研究进展

非酒精性脂肪肝病是以肝细胞内脂肪过度沉积为主要特征的代谢性疾病，脂肪主要以甘油三酯的形式存在，由甘油和脂肪酸通过酯化作用形成；而且肿瘤细胞中脂肪酸的合成异常活跃，明显高于正常细胞，为肿瘤细胞旺盛的增殖、发育过程中生物膜的形成、信号分子和能量的产生提供必要的脂质底物。乙酰辅酶A羧化酶(acetyl-CoA carboxylase，ACC)是脂肪酸从头合成过程的限速酶，同时也是催化该脂肪酸合成通路中第一步反应的酶；其催化生成的产物丙二酰辅酶A亦能抑制脂肪酸的氧化。因此，ACC抑制能降低脂肪酸合成和促进脂肪酸氧化，降低体内脂肪酸的含量，进而减弱肝细胞内脂肪的堆积来达到改善非酒精性脂肪肝病；同时体内脂肪酸含量的降低使肿瘤细胞发育所必须的脂质底物得不到满足，从而能够抑制肿瘤组织的发育，所以乙酰辅酶A羧化酶抑制剂有望成为新型治疗非酒精性脂肪肝病和肿瘤的药物。本文对ACC的结构特点、作用机制及其抑制剂的研究进展进行了综述。     

维生素K代谢相关基因CYP4F2参与凝血因子FⅨ活化的研究

目的探索维生素K代谢相关基因CYP4F2对维生素K依赖性凝血因子活化(凝血因子FⅨ为例)的影响。方法构建同时含有CYP4F2-cDNA片段与FⅨ-cDNA片段的pIRES质粒,通过酶切验证。使用Lipofectamine 2000转染试剂,将构建成功的pIRES-FⅨ-CYP4F2质粒以及pIRES-FⅨ质粒、pIRES空白对照质粒瞬时转染LO2细胞。在不同质粒转染的细胞中,通过Western blotting验证CYP4F2和FⅨ蛋白的表达,应用FⅨa Assay检测试剂盒检测FⅨa活性。结果经酶切证实,pIRES-FⅨ-CYP4F2质粒构建成功。Western blotting证实,pIRES-FⅨ及pIRES-FⅨ-CYP4F2质粒成功转染LO2细胞。FⅨa Assay检测发现,在过表达FⅨ的LO2细胞培养上清和细胞裂解液中,FⅨa活性较对照组显著升高;当同时过表达CYP4F2和FⅨ后,LO2细胞培养上清和细胞裂解液中的FⅨa活性较单独过表达FⅨ组明显降低。结论维生素K代谢相关基因CYP4F2的过表达对维生素K依赖性FⅨ的活化具有抑制作用。     

Autotrophy as a predominant mode of carbon fixation in anaerobic methane-oxidizing microbial communities

The methane-rich, hydrothermally heated sediments of the Guaymas Basin are inhabited by thermophilic microorganisms, including anaerobic methane-oxidizing archaea (mainly ANME-1) and sulfate-reducing bacteria (e.g., HotSeep-1 cluster). We studied the microbial carbon flow in ANME-1/ HotSeep-1 enrichments in stable-isotope–probing experiments with and without methane. The relative incorporation of ¹³C from either dissolved inorganic carbon or methane into lipids revealed that methane-oxidizing archaea assimilated primarily inorganic carbon. This assimilation is strongly accelerated in the presence of methane. Experiments with simultaneous amendments of both ¹³C-labeled dissolved inorganic carbon and deuterated water provided further insights into production rates of individual lipids derived from members of the methane-oxidizing community as well as their carbon sources used for lipid biosynthesis. In the presence of methane, all prominent lipids carried a dual isotopic signal indicative of their origin from primarily autotrophic microbes. In the absence of methane, archaeal lipid production ceased and bacterial lipid production dropped by 90%; the lipids produced by the residual fraction of the metabolically active bacterial community predominantly carried a heterotrophic signal. Collectively our results strongly suggest that the studied ANME-1 archaea oxidize methane but assimilate inorganic carbon and should thus be classified as methane-oxidizing chemoorganoautotrophs.