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Mediators of Inflammation
Volume 2016, Article ID 1605948, 10 pages
http://dx.doi.org/10.1155/2016/1605948
Research Article

CD97/ADGRE5 Inhibits LPS Induced NF-κB Activation through PPAR-γ Upregulation in Macrophages

Department of Cardiology, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310000, China

Received 16 October 2015; Revised 28 December 2015; Accepted 28 December 2015

Academic Editor: Tânia Silvia Fröde

Copyright © 2016 Shuai Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

CD97/ADGRE5 protein is predominantly expressed on leukocytes and belongs to the EGF-TM7 receptors family. It mediates granulocytes accumulation in the inflammatory tissues and is involved in firm adhesion of PMNC on activated endothelial cells. There have not been any studies exploring the role of CD97 in LPS induced NF-κB activation in macrophages. Therefore, we first measured the CD97 expression in LPS treated human primary macrophages and subsequently analyzed the levels of inflammatory factor TNF-α and transcription factor NF-κB in these macrophages that have been manipulated with either CD97 knockdown or overexpression. We found that a reported anti-inflammatory transcription factor, PPAR-γ, was involved in the CD97 mediated NF-κB suppression. Furthermore, by immunofluorescence staining, we established that CD97 overexpression not only inhibited LPS induced p65 expression in the nucleus but also promoted the PPAR-γ expression. Moreover, using CD97 knockout THP-1 cells, we further demonstrated that CD97 promoted PPAR-γ expression and decreased LPS induced NF-κB activation. In conclusion, CD97 plays a negative role in LPS induced NF-κB activation and TNF-α secretion, partly through PPAR-γ upregulation.