Costimulation of Fibroblast Collagen and Transforming Growth Factor β1 Gene Expression by Monocyte Chemoattractant Protein-1 via Specific Receptors

Abstract

Recent studies indicate potential roles of monocyte chemotactic protein-1 (MCP-1) in recruitment of monocytes to sites of inflammation. However, their increased expression does not always correlate with monocyte influx, suggesting other possible biological activities for this member of the C-C chemokine family. In view of its potential role in regulating extracellular matrix expression in fibrotic disorders, the effects of MCP-1 on lung fibroblast collagen expression were evaluated. Isolated rat lung fibroblasts were treated with increasing doses of MCP-1 for variable periods of time and examined for effects on collagen synthesis and expression of procollagen ␣ 1 (I) mRNA expression. The results show that MCP-1 was able to stimulate collagen expression in these cells in a dose-dependent manner but required over 24 h for significant elevation to occur. In view of this delayed time course, the possibility of mediation via endogenous transforming growth factor ␤ (TGF␤) was tested by the ability of anti-TGF␤ antibody to inhibit this MCP-1 stimulation of collagen expression. Significant but incomplete inhibition by this antibody was observed. Pretreatment of the cells with antisense but not by sense or missense TGF␤ 1 oligodeoxyribonucleotides caused essentially complete inhibition of this MCP-1 stimulatory effect. Furthermore, MCP-1 treatment was found to also stimulate TGF␤ secretion and mRNA expression, which was also abolished by pretreatment with antisense TGF␤ 1 oligodeoxyribonucleotides. The kinetics of TGF␤ expression indicates that significant increase preceded that for collagen expression. Binding studies using 125 I-labeled MCP-1 indicated the presence of specific and saturable binding sites with a dissociation constant consistent with the dose response curves for stimulation of fibroblast collagen synthesis and TGF␤ activity by MCP-1. These results taken together suggest that MCP-1 stimulates fibroblast collagen expression via specific receptors and endogenous up-regulation of TGF␤ expression. The latter then results in autocrine and/or juxtacrine stimulation of collagen gene expression.Monocyte chemoattractant protein-1 (MCP-1 1

Monocyte chemoattractant protein-1 has prosclerotic effects both in a mouse model of experimental diabetes and in vitro in human mesangial cells

“…Exposure to MCP-1 induced a statistically significant 2.5-fold increase in fibronectin protein levels at 24 h, which was comparable with the increase in extracellular matrix induced by MCP-1 in rat lung fibroblasts [31]. The rise in fibronectin protein levels in the supernatant fraction was followed by a significant increase in pericellular polymeric fibronectin, indicating enhanced fibronectin incorporation in the matrix.…”

“…SB202190 and the rabbit anti-fibronectin antibody were from Calbiochem (Nottingham, UK). The protein kinase C (PKC) peptide inhibitors PKC [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] and SN50 were from Alexis (Nottingham, UK) and the TransAM nuclear factor kappa B (NF-κB) kit was from Active Motif (Rixensart, Belgium). The FITC-conjugated rabbit antimouse antibody, the rabbit anti-fibronectin antibody and the avidin/biotin blocking solution were from DAKOCytomation (Glostrup, Denmark).…”

“…Inhibition experiments on basal protein production were carried out simultaneously. RS102895 (6 μmol/l), anti-TGF-β1 neutralising antibody (2 μg/ml), SN50 (18 μmol/l), SB202190 (1 μmol/l) and PKC [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] (4 μmol/l) were used to block CCR2, TGF-β1, NF-κB, p38 mitogen-activated protein (MAP) kinase and PKC, respectively. The specificity and selectivity of the inhibitors used has been previously demonstrated [22][23][24][25].…”

“…Results are expressed as fold increase over control. n=3; *p<0.05 for MCP-1, MCP-1 + PKC [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] and MCP-1 + SB202190 vs control. b Serum-deprived HMCs were exposed to rh-MCP-1 (10 ng/ ml) for 0, 30, 60 and 120 min.…”

Evaluation of chemokines CXCL8 and CCL2, serotonin, and vascular endothelial growth factor serum concentrations in healthy dogs from seven breeds with variable predisposition for canine idiopathic pulmonary fibrosis

“…In humans, both CXCL8 and CCL2 concentrations were found to be increased in blood (Ziegenhagen et al, 1998a;Suga et al, 1999;Fujiwara et al, 2012) and bronchoalveolar lavage fluid (BALF) (Capelli et al, 2005;Antoniou et al, 2006;Baran et al, 2007) of IPF patients compared with healthy volunteers and correlated with lung function (Capelli et al, 2005;Emad and Emad, 2007;Martina et al, 2009;Vasakova et al, 2009), disease progression (Ziegenhagen et al, 1998b;Totani et al, 2002), and outcome (Shinoda et al, 2009;Richards et al, 2012). Furthermore, several studies suggested an involvement of the chemokine CCL2 in the pathogenesis of IPF, notably through its action on resident pulmonary fibroblast and circulating fibrocytes, promoting the generation of abundant extracellular matrix in the lungs (Gharaee-Kermani et al, 1996;Phillips et al, 2004;Moore et al, 2005;Inomata et al, 2014). Such strong evidence involving CXCL8 in the pathogenesis of the disease are lacking, although this chemokine is thought to act as a pro-fibrotic factor in IPF via the promotion of exacerbated angiogenesis (Strieter et al, 2002;Rosenkilde and Schwartz, 2004;Antoniou et al, 2006;Martina et al, 2009;Cui et al, 2010).…”