Des-acyl ghrelin protects microvascular endothelial cells from oxidative stress-induced apoptosis through sirtuin 1 signaling pathway

详细信息    查看全文

• 作者：Takeshi Shimada ; Hiroto Furuta ; ^{hfuruta@wakayama-med.ac.jp" class="auth_mail} ; Asako Doi ; Hiroyuki Ariyasu ; Hiromichi Kawashima ; Hisao Wakasaki ; Masahiro Nishi ; Hideyuki Sasaki ; Takashi Akamizu
• 关键词：Des-G ; des-acyl ghrelin ; GHS-R ; growth hormone-secretagogue receptor ; SIRT ; sirtuin ; siRNA ; small interfering ribonucleic acid
• 刊名：Metabolism
• 出版年：April, 2014
• 年：2014
• 卷：63
• 期：4
• 页码：469-474
• 全文大小：439 K

文摘

Objective

Ghrelin is a stomach-derived hormone. Acylation of ghrelin has been essential for its biological activities such as stimulating appetite. On the other hand, the function of des-acyl ghrelin (Des-G) has not been fully elucidated. The aim of the present study is to examine the anti-apoptotic effect of Des-G on endothelial cells.

Materials/Methods

After human retinal microvascular endothelial cells (RMECs) were pretreated with or without 100 nmol/L Des-G, apoptosis was induced with 0.1 mmol/L hydrogen peroxide (H₂O₂). For pharmacological inhibition of surtuin 1 (SIRT1) catalytic activity, the cells were treated with 10 渭mol/L Ex-527. Inhibition of SIRT1 with siRNA was also performed. The quantitative estimation of DNA fragmentation was used as a marker of apoptosis. Furthermore, total SIRT activity in nuclear extracts, mRNA and protein levels of SIRT1, manganese superoxide dismutase (MnSOD) and catalase were determined.

Results

Des-G pretreatment protected RMECs from oxidative stress-induced apoptosis and increased SIRTs deacetylase activity in nuclear extracts. On the other hand, both pharmacological and siRNA mediated inhibition of SIRT1 attenuated the anti-apoptotic effect of Des-G. Moreover, Des-G increased mRNA and protein levels of SIRT1 and antioxidant enzymes such as MnSOD and CAT, which are downstream targets of SIRT1. Although the treatment of Ex-527 did not alter mRNA expression levels of SIRT1, it decreased mRNA expression levels of antioxidant enzymes in the cells with Des-G pretreatment.

Conclusions

Our results suggest that SIRT1 signaling pathway contributes to protective effect of Des-G against oxidative stress-induced apoptosis.