PEDF调控HSL抑制肥胖状态下脂肪动员的作用及机制

PEDF regulates hormone-responsive lipase HSL to suppress fat mobilization in obese states

目的探讨色素上皮衍生因子(PEDF)调控激素敏感性脂肪酶(HSL)抑制肥胖状态下脂肪动员的作用及机制。方法构建高脂喂养的肥胖小鼠模型,应用Western blot和荧光定量PCR检测PEDF和HSL的蛋白及mRNA水平;腹腔注射异丙肾上腺素(ISO)模拟激素诱导脂肪动员过程,应用Western blot检测HSL的磷酸化水平;培养3T3-L1并诱导分化为脂肪细胞,分别加ISO和AMPK激动剂利用Western blot研究PEDF调控HSL的分子机制。结果Western blot和荧光定量PCR检测结果提示高脂组PEDF蛋白水平和mRNA含量在各个时间点(4、8、12、16、20周)较普通组均明显上调,而HSL蛋白和mRNA水平在各个时间点较普通组均显著下调。在ISO诱导下,不同浓度(10、100、500 nmol/L)PEDF显著下调HSL磷酸化水平。Western blot检测提示PEDF可以同时下调脂肪细胞AMPK和HSL磷酸化水平。结论 PEDF可能通过抑制AMPK的磷酸化调控HSL,导致肥胖状态下体内甘油三酯进一步蓄积,最终诱导胰岛素抵抗等代谢异常疾病。

Objective To investigate the role of pigment epithelium-derived factor（PEDF）on regulating hormone-sensitivetriglayceride lipase（HSL）to inhibit the process of fat mobilization in obesity. Methods HFD- induced obesity animalmodels were established. Western blot and QPCR examination determined the protein expression and mRNA level of PEDFand HSL;the process of fat mobilization was mimicked through isoproterenol（ISO） intraperitoneal injection. HSLphosphorylation was detected by Western blot. 3T3-L1 was cultured and induced to differentiate into adipocytes by addingISO and AMPK agonists. Western blot was used to study the molecular mechanism of HSL regulated by PEDF. Results Westernblot and QPCR examination showed that adipose PEDF protein expression and mRNA levels were significantly increasedcompared with chow-fed group,while adipose HSL protein was decreased. Moreover in vivo studies demonstrated that PEDFinhibited ISO-stimulated lipolysis through down-regualting HSL protein phosphorylation. In vitro studies further confirmedthat PEDF probably inhibited the phosphorylation of AMPK and HSL protein. Conclusion PEDF could regulate HSL viainhibiting phosphorylation of AMPK,leading to the accumulation of triglycerides which finally result in progressive obesityand insulin resistance.