生长激素释放肽通过激活哺乳动物雷帕霉素靶蛋白／p70S6K 通路促进人脐静脉内皮细胞增殖的观察

摘要

目的：探讨促生长激素释放肽（Ghrelin）促进人脐静脉内皮细胞（HUVEC）增殖的分子机制。方法将 HUVEC分为正常对照（Con）组、Ghr组、D‐Lys‐3‐GHRP组、Ghr＋D‐Lys‐3‐GHRP组、雷帕霉素（Rapa）组及Ghr＋Rapa组，采用MTT法检测细胞增殖能力，Western blot检测HUVEC中Gh‐relin受体（GHSR1a）的表达及哺乳类雷帕霉素靶蛋白（mTOR）、p70S6K和S6的磷酸化水平。结果与Con组相比，MTT检测显示Ghr组细胞增殖增强，且高于Ghr＋D‐Lys‐3‐GHRP组和Ghr＋ Rapa组；Western blot检测显示，与Con组比较，mTOR、p70S6K和S6在Ghr组快速磷酸化，Ghr＋D‐Lys‐3‐GH‐RP组mTOR、P70S6K和S6磷酸化水平低于Ghr组。结论 Ghrelin与其受体GHSR1a结合后，活化mTOR／p70S6K信号通路，促进HUVEC增殖。%Objective To investigate the molecular mechanism of ghrelin in promoting HUVECs proliferation. Methods HUVECs were divided into six groups :the normal control group ,the Ghr group ,the D‐Lys‐3‐GHRP group ,the Ghr+ D‐Lys‐3‐GHRP group ,the Rapa group and the Ghr+ Rapa group. The proliferation of HUVECs were determined by MTT assay. The expression of GHSR1a and the phosphorylation level of mTOR ,P70S6K and S6 were detected by western blot. Results Compared with the normal control group ,the proliferation of HUVEC was increased in ghrelin group ,and significantly higher in Ghr group than in Ghr+ D‐Lys‐3‐GHRP group and Ghr+ Rapa group. Western blot showed a rapid phosphorylation of mTOR ,P70S6K and S6 in Ghr group than in control group. The phosphorylation level of mTOR ,P70S6K and S6 in Ghr + D‐Lys‐3‐GHRP group was lower than in ghrelin group.Conclusion The results demonstrated that ghrelin promotes HUVECs proliferation by binding to GHSR1a and activating mTOR/P70S6K signaling pathway.