Angiotensin II-induced pro-fibrotic effects require p38MAPK activity and transforming growth factor beta 1 expression in skeletal muscle cells

2012 ◽  
Vol 44 (11) ◽  
pp. 1993-2002 ◽  
Author(s):  
María Gabriela Morales ◽  
Yaneisi Vazquez ◽  
María José Acuña ◽  
Juan Carlos Rivera ◽  
Felipe Simon ◽  
...  
1996 ◽  
Vol 270 (1) ◽  
pp. R145-R152 ◽  
Author(s):  
G. Williams ◽  
L. Becker ◽  
D. Bryant ◽  
S. Willis ◽  
B. P. Giroir

The production of nitric oxide (NO) via the inducible form of NO synthase (iNOS) is regulated by a complex network of cytokines and endogenous hormones. Among these, transforming growth factor-beta (TGF-beta 1) is known to suppress iNOS expression and NO production by many cell types. To determine the effect of TGF-beta 1 on NO production by skeletal muscle cells, we stimulated C2C12 myocytes with interferon-gamma (IFN) and interleukin-1 (IL-1) in the presence or absence of TGF-beta 1. In contrast to findings in macrophages, TGF-beta 1 markedly enhanced NO production by skeletal muscle cells. Increases in NO production reflected significant increases in iNOS immunoreactive protein and iNOS mRNA. Elevated iNOS mRNA levels associated with TGF-beta 1 treatment were not due to an alteration in mRNA stability, but rather reflected a significantly increased transcriptional rate of the iNOS gene. These findings indicate that TGF-beta 1 enhances iNOS expression in skeletal muscle cells and suggest that the regulation of NO production by TGF-beta 1 may depend on the cell type studied.


1989 ◽  
Vol 109 (1) ◽  
pp. 309-315 ◽  
Author(s):  
Y Sato ◽  
D B Rifkin

When a confluent monolayer of bovine aortic endothelial (BAE) cells is wounded with a razor blade, endothelial cells (ECs) spontaneously move into the denuded area. If bovine pericytes or smooth muscle cells (SMCs) are plated into the denuded area at low density, they block the movement of the ECs. This effect is dependent upon the number of cells plated into the wound area and contact between ECs and the plated cells. Antibodies to transforming growth factor-beta 1 (TGF-beta 1) abrogate the inhibition of BAE cell movement by pericytes or SMCs. TGF-beta 1, if added to wounded BAE cell monolayers, also inhibits cell movement. When cultured separately, BAE cells, pericytes, and SMCs each produce an inactive TGF-beta 1-like molecule which is activated in BAE cell-pericyte or BAE cell-SMC co-cultures. The activation appears to be mediated by plasmin as the inhibitory effect on cell movement in co-cultures of BAE cells and pericytes is blocked by the inclusion of inhibitors of plasmin in the culture medium.


Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Maria Nataatmadja ◽  
Jennifer West ◽  
Malcolm West

Increased expression of transforming growth factor-beta (TGFβ) and Smad3 is associated with fibrosis and inflammatory cell infiltration in abdominal aortic aneurysm. In Smad3-null mice there is reduced extracellular matrix (ECM) deposition but enhanced neointimal hyperplasia in response to vascular injury suggesting a TGFβ/Smad3 role in ECM regulation and cell proliferation. In vitro studies show that exogenous TGFβ administration leads to phosphorylation and nuclear translocation of Smad3 while angiotensin II (AngII) induces fibrosis through TGFβ and Smad3 pathways. We investigated TGFβ/Smad3 signaling using immunohistochemical and cell culture studies in thoracic aortic aneurysm tissue derived from subjects with Marfan syndrome (MFS; 3M, 2F, 46±24yr, mean +/−SD) and bicuspid aortic valve malformation (BAV; (3M, 2F, 65±13yr) as well as normal aorta from organ donor subjects (3M, 2F 40±11yr). MFS and BAV tissue showed co-localisation of TGFβ1–3 and Smad3 in myofibroblasts, vascular smooth muscle cells (VSMCs) and chronic inflammatory cells in the subintimal layer and tunica media and in fibroblasts in tunica adventitia. In normal aortic wall there was minimal TGFβ and Smad3 staining. Cultured VSMCs (passage 1–5) from MFS and BAV showed nuclear Smad3 and strong cytoplasmic TGFβ1–3 expression in numerous vesicles and in areas of exocytosis and extracellular localisation. In control cells there was much weaker TGFβ1–3 staining compared to aneurysm derived cells. Smad3 staining in normal cells was located in the cytoplasm alone. Compared to normal tissue and cells AngII receptor type1 and 2 (ATR1 and 2) expression was increased in both aneurysm tissue and in cultured VSMCs derived from aneurysm. Cultured VSMCs were treated for 48h with the ATR1 antagonist losartan (10μM). This caused disappearance of TGFβ1–3 vesicle localisation and nuclear expression of Smad3. The findings of increased TGFβ1–3 and Smad3 expression in aneurysm tissue and cultured cells are consistent with aberrant TGFβ signalling and with activation of the Smad3 signalling pathway. Furthermore reduction in extracellular TGFβ and de-activation of Smad3 expression associated with losartan treatment supports a role for ATR1 antagonism in inhibition of aneurysm progression. Figure 1: Risk of IMH Conversion to Typical Dissection


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