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This Article Accepted manuscript (PDF) All Versions of this Article: JME-08-0021v1 41/5/393    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Xiaohui, W. Articles by Lu, J. Search for Related Content PubMed PubMed Citation Articles by Xiaohui, W. Articles by Lu, J.

W Xiaohui, China
L Yidong, Department of Pathophysiology,, Second Military Medical University, Shanghai, China
Z Xiaoyan, Pathophysiology, Second Military Medical University, shanghai, China
W Yan, Shanghai, China
D Fei,
J Lu, Shanghai, China

Correspondence: Wang Xiaohui, Email: wangpan96{at}yahoo.com.cn

Abstract

Glucocorticoid (GC) effectively suppresses immune and inflammatory responses and inhibits the growth of several types of cells, but the role of GC and its receptor on macrophage proliferation is unclear. In our previous work we found RAW-GR(-) cells (murine macrophage RAW264.7 cells stably transfected with GR-siRNA expression vector by RNA interference) grew faster by about 2- fold. In this study we further explored the role and mechanisms of GC/GR on the proliferation of macrophage. We found that the growth of RAW264.7 cells was inhibited by Dex in a concentration dependent manner. The mRNA and protein levels of signal regulatory protein1 (SIRP1) were induced by GC/GR in RAW264.7 cells and SIRP1 expression was decreased remarkably in RAW-GR(-) cells. Overexpression of SIRP1 negatively regulated RAW-GR(-) cells proliferation, and inhibition of SIRP1 expression by small interference RNA attenuated Dex-induced proliferation inhibition in RAW264.7 cells. The proliferation inhibition of GC/GR was also found in mouse peritoneal macrophage, which was associated with increase of SIRP1 induced by GC/GR as well. In addition, elevation of expression of cdk2, cyclinD1 and cyclinB1 but not phosphorylated-ERK1/2 and p38 were found in RAW-GR(-) cells. In conclusion, we provided the novel evidences that GC/GR inhibited the growth of RAW264.7 cells and mouse peritoneal macrophage, and the antiproliferative effect of GC/GR on these cells was at lease in part resulted from GC/GR-induced SIRP1 expression. Upregulation of cdk2, cyclinD1 and cyclinB1 was also related to the increased proliferation of RAW-GR(-) cells.