Song Xiaoxiao, Yang Boyun, Qiu Fuyu, Jia Minyue, Fu Guosheng
The Department of Endocrinology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310009, Zhejiang Province, China.
The Department of Cardiology, Biomedical Research (Therapy) Center, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou 310016, Zhejiang Province, China.
Cell Biol Int. 2017 Oct;41(10):1146-1159. doi: 10.1002/cbin.10833. Epub 2017 Aug 23.
The objective of the research was to investigate the function of endothelial progenitor cells (EPCs) in the conditions of high glucose and lipids, which has been widely used to mimic the metabolic disorder that occurs in type 2 diabetic mellitus, and further to verify the role of PGC-1α and SIRT1, cellular energy metabolism regulators, in the process of senescence of EPCs with these combined stimuli. Circulating EPCs were incubated in absence or presence of high glucose (25 mM), FFA (200 µM) or both. EPCs senescence was assessed by β-galactosidase staining, EPCs telomerase activity was measured by telomeric repeat ampli-fication protocol assay, in vitro angiogenesis assay and MTT assays were performed to assess angiogenesis and proliferation ability of EPCs. The results showed that combined stimuli inhibited EPCs reendothelialization ability in vitro, accelerated EPCs senescence and decreased the telomerase activity. Meanwhile, with combined stimuli, the expression of PGC-1α increased whereas SIRT1 expression decreased in EPCs accompanied by activation of P53/P21 signaling pathway. Conversely, transfection of EPCs with PGC-1α-siRNA rescued EPCs premature senescence and up-regulated SIRT1 and decreased P53/P21 expression, correlating closely with the down-regulation of PGC-1α itself. In addition, the combined stimuli induced up-regulation of PGC-1α expression was partly mediated by ROS and P38 signaling pathway. Overall, the data presented here identify PGC-1α as a potent negative regulator of EPCs' senescence under combined stimuli, which is partly mediated by SIRT1/P53/P21 signaling pathway.
该研究的目的是探究内皮祖细胞（EPCs）在高糖和高脂条件下的功能，高糖和高脂条件已被广泛用于模拟2型糖尿病中出现的代谢紊乱，进而验证细胞能量代谢调节因子PGC-1α和SIRT1在这些联合刺激下EPCs衰老过程中的作用。将循环EPCs在不存在或存在高糖（25 mM）、游离脂肪酸（FFA，200 μM）或两者的情况下进行孵育。通过β-半乳糖苷酶染色评估EPCs衰老，通过端粒重复序列扩增协议分析测定EPCs端粒酶活性，进行体外血管生成分析和MTT分析以评估EPCs的血管生成和增殖能力。结果显示，联合刺激在体外抑制EPCs的再内皮化能力，加速EPCs衰老并降低端粒酶活性。同时，在联合刺激下，EPCs中PGC-1α的表达增加而SIRT1的表达降低，同时伴有P53/P21信号通路的激活。相反，用PGC-1α-siRNA转染EPCs可挽救EPCs的早衰，上调SIRT1并降低P53/P21的表达，这与PGC-1α自身的下调密切相关。此外，联合刺激诱导的PGC-1α表达上调部分由活性氧（ROS）和P38信号通路介导。总体而言，此处呈现的数据确定PGC-1α是联合刺激下EPCs衰老的有效负调节因子，这部分由SIRT1/P53/P21信号通路介导。
