Angiotensin-(1-7) suppresses the number and function of the circulating fibrocytes by upregulating endothelial nitric oxide synthase expression.

Abstract

There is growing evidence suggesting that circulating fibrocytes (CFs) play a pivotal role in tissue repair and fibrosis. In contrast, in recent studies, angiotensin-(1-7) [Ang-(1-7)] has been shown to antagonize fibrosis. The purpose of this study was to examine the direct effect of Ang-(1-7) on CFs. Total mononuclear cells (MNCs) were isolated from peripheral blood by Ficoll density gradient centrifugation. Using laser scanning confocal microscopy, CFs were identified as adherent cells that stained positive for both CD34 and collagen-I. After 14 days of culture, CFs were stimulated with Ang-(1-7) at concentrations of 10 nM, 100 nM, 1 μM or 10 μM, in the absence and presence of pretreatment with A-779, N(G)-nitro-L-arginine methyl ester (L-NAME) or both, for 24, 48 or 72 h. The number of cells, cellular proliferation, and level of apoptosis were determined by hematoxylin and eosin staining, the Cell Counting Kit-8 (CCK8) assay and the annexin V/propidium iodide binding assay, respectively. The collagen content of CFs was measured by the concentration of hydroxyproline, which was detected using the enzymatic digestion method. The expression of endothelial nitric oxide synthase (eNOS) was assayed by western Blot analysis, while nitric oxide (NO) generation was detected using the Griess method. We found that Ang-(1-7) increases apoptosis and eNOS/NO production in CFs. In addition, Ang-(1-7) decreases the number, proliferative capacity and collagen-secretion of CFs in a concentration- and time-dependent manner. These data suggest that Ang-(1-7) suppresses the both the number and function of CFs possibly by increasing eNOS/NO production in the CFs.

• Authors: Kan Wang, Xiaosheng Hu, Changqing Du, Shike Tu, Furong Zhang, Xudong Xie
• Journal: Molecular and cellular biochemistry (Mol Cell Biochem) Vol. 365 Issue 1-2 Pg. 19-27 (Jun 2012) ISSN: 1573-4919 [Electronic] Netherlands
• PMID: 22456996 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• 7-Ala-angiotensin (1-7)
• Collagen Type I
• Peptide Fragments
• Angiotensin II
• Nitric Oxide
• Angiotensin I
• NOS3 protein, human
• Nitric Oxide Synthase Type III
• angiotensin I (1-7)
• Hydroxyproline
• NG-Nitroarginine Methyl Ester

Topics

• Angiotensin I (pharmacology)
• Angiotensin II (analogs & derivatives, pharmacology)
• Apoptosis
• Blood Cells (enzymology, metabolism)
• Cell Proliferation
• Cells, Cultured
• Collagen Type I (metabolism)
• Fibroblasts (drug effects, enzymology, metabolism)
• Humans
• Hydroxyproline (metabolism)
• NG-Nitroarginine Methyl Ester (pharmacology)
• Nitric Oxide (metabolism)
• Nitric Oxide Synthase Type III (antagonists & inhibitors, genetics, metabolism)
• Peptide Fragments (pharmacology)
• Up-Regulation