体内肉碱来源及其对脂类代谢的影响

肉碱是体内一种有多种生理功能的氨基酸类物质,其在脂类代谢过程中有重要的调节作用,近年来在甘油三脂血症、肾透析患者的脂代谢障碍的辅助治疗中取得了较好疗效。本文就肉碱的来源和对脂类代谢的影响进行了讨论。     

灵芝子实体多糖对小鼠急性酒精肝损伤预防的代谢组分析

灵芝多糖是灵芝的主要药理活性成分之一。本研究通过检测血清指标分析灵芝子实体多糖（Ganoderma lingzhi fruitbody polysaccharides,GLFPS）对小鼠急性酒精性肝损伤的预防作用并结合代谢组学探究作用机制。结果显示,GLFPS显著抑制因酒精作用而升高的小鼠血清中ALT、AST、TG、TC和ADH水平。通过代谢组分析,在模型组与对照组中得到85个差异代谢物,其中三磷酸腺苷（adenosine triphosphate）、L-天门冬氨酸（L-aspartic acid）以及赖氨酸（L-lysine）等在相互作用网络中起重要作用,说明酒精能引起小鼠肝脏腺苷和氨基酸代谢的改变。GLFPS组与模型组有58个差异代谢物,主要包括脂质和有机氧化物,说明GLFPS可以通过调节小鼠肝脏中脂质与有机化合物代谢来预防急性酒精肝损伤。对差异代谢物进行KEGG富集分析发现主要涉及胆碱代谢、甘油磷脂代谢和ABC转运蛋白。GLFPS能够有效缓解这3个代谢通路中因酒精作用发生明显改变的代谢。综上可见,灵芝子实体多糖能够通过调节小鼠胆碱代谢、甘油磷脂代谢以及部分ABC转运蛋白有效预防酒精性肝损伤。     

Isolation of lipids from biological samples

Abstract

Isolation of the lipid fraction from biological samples has been a crucial part of countless studies over the last century. This considerable research interest has led to the development of a number of methods for isolating a range of molecular species that fall under the umbrella term “lipid”. Such methods vary in popularity, complexity, specificity and even toxicity. In this review, we explore examples of published methods (1952–2014) for isolating lipids from biological samples and attempt to assess the limits of techniques both from a chemical and biological perspective. We also suggest how a suitable method might be chosen for a novel application.     

Glycerol-3-phosphate Acyltransferase Isoform-4 (GPAT4) Limits Oxidation of Exogenous Fatty Acids in Brown Adipocytes

Glycerol-3-phosphate acyltransferase-4 (GPAT4) null pups grew poorly during the suckling period and, as adults, were protected from high fat diet-induced obesity. To determine why Gpat4^−/− mice failed to gain weight during these two periods of high fat feeding, we examined energy metabolism. Compared with controls, the metabolic rate of Gpat4^−/− mice fed a 45% fat diet was 12% higher. Core body temperature was 1 ºC higher after high fat feeding. Food intake, fat absorption, and activity were similar in both genotypes. Impaired weight gain in Gpat4^−/− mice did not result from increased heat loss, because both cold tolerance and response to a β3-adrenergic agonist were similar in both genotypes. Because GPAT4 comprises 65% of the total GPAT activity in brown adipose tissue (BAT), we characterized BAT function. A 45% fat diet increased the Gpat4^−/− BAT expression of peroxisome proliferator-activated receptor α (PPAR) target genes, Cpt1α, Pgc1α, and Ucp1, and BAT mitochondria oxidized oleate and pyruvate at higher rates than controls, suggesting that fatty acid signaling and flux through the TCA cycle were enhanced. To assess the role of GPAT4 directly, neonatal BAT preadipocytes were differentiated to adipocytes. Compared with controls, Gpat4^−/− brown adipocytes incorporated 33% less fatty acid into triacylglycerol and 46% more into the pathway of β-oxidation. The increased oxidation rate was due solely to an increase in the oxidation of exogenous fatty acids. These data suggest that in the absence of cold exposure, GPAT4 limits excessive fatty acid oxidation and the detrimental induction of a hypermetabolic state.     

LncRNA与肝脏糖脂代谢的研究进展

长链非编码RNA(Long non-coding RNA,lncRNA)因参与多个层级上的生物进程而成为当下生命科学领域的研究热点.LncRNA可以与DNA、RNA和蛋白质等生物分子结合,并进一步影响靶基因的转录、翻译以及翻译后修饰等过程,从而发挥在细胞生理代谢过程中的调控作用.目前研究显示,lncRNA通过多种途径在...     

孕烷X受体研究进展

孕烷X受体(pregnane X receptor,PXR)是核受体超家族成员之一,以同名内源性配体孕烷命名,主要表达在肝脏、小肠、胃、肾脏等组织,在机体异源性/内源性物质的代谢及排泄过程中起重要的调节作用。近年的研究表明,PXR还可以通过调节其下游靶基因的表达,直接参与机体脂质、胆固醇和糖代谢,维持机体内环境的稳态。本文将就PXR的研究进展做一综述。