Modulatory effect of interleukin-1α on expression of structural matrix proteins, MMPs and TIMPs in human cardiac myofibroblasts: Role of p38 MAP kinase

Abstract

The proinflammatory cytokine interleukin-1 (IL-1) elicits catabolic effects on the myocardial extracellular matrix (ECM) early after myocardial infarction but there is little understanding of its direct effects on cardiac myofibroblasts (CMF), or the role of p38 mitogen-activated protein kinase (MAPK). We used a focused RT-PCR microarray to investigate the effects of IL-1α on expression of 41 ECM genes in CMF cultured from different patients, and explored regulation by p38 MAPK.IL-1α (10 ng/ml, 6 h) had minimal effect on mRNA expression of structural ECM proteins, including collagens, laminins, fibronectin and vitronectin. However, it induced marked increases in expression of specific ECM proteases, including matrix metalloproteinases MMP-1 (collagenase-1), MMP-3 (stromelysin-1), MMP-9 (gelatinase-B) and MMP-10 (stromelysin-2). Conversely, IL-1α reduced mRNA and protein expression of ADAMTS1, a metalloproteinase that suppresses neovascularization. IL-1α increased expression of TIMP-1 slightly, but not TIMP-2. Data for MMP-1, MMP-2, MMP-3, MMP-9, MMP-10 and ADAMTS1 were confirmed by quantitative real-time RT-PCR. Tumor necrosis factor-alpha (TNFα), another important myocardial proinflammatory cytokine, did not alter expression of these metalloproteinases. IL-1α strongly activated the p38 MAPK pathway in human CMF. Pharmacological inhibitors of p38-α/β (SB203580) or p38-α/β/γ/δ (BIRB-0796) reduced MMP-3 and ADAMTS1 mRNA expression, but neither inhibitor affected MMP-9 levels. MMP-1 and MMP-10 expression were inhibited by BIRB-0796 but not SB203580, suggesting roles for p38-γ/δ.In summary, IL-1α induces a distinct pattern of ECM protein and protease expression in human CMF, in part regulated by distinct p38 MAPK subtypes, affirming the key role of IL-1α and CMF in post-infarction cardiac remodeling.

Inflammatory and fibrotic responses of cardiac fibroblasts to myocardial damage associated molecular patterns (DAMPs)

“…Thus, CF may contribute to the inflammatory milieu that occurs in the myocardium early after MI [10,95]. In addition to this inflammatory response, we [7,88,93,94,[96][97][98] and others [61,99,100] have demonstrated that CF alter the balance of cardiac ECM turnover in favour of degradation in response to IL-1; for example by increasing secretion of MMPs, decreasing collagen synthesis and decreasing expression of profibrotic factors (e.g. connective tissue growth factor).…”

Effects of interleukin-1 on cardiac fibroblast function: Relevance to post-myocardial infarction remodelling

“…CF are capable of expressing several, but not all, members of the MMP family in a regulated manner (Turner and Porter, 2012). In our own studies, human CF were found to express particularly high basal mRNA levels of MMP-1 (interstitial collagenase), MMP-2 (gelatinase A), MMP-14 (MT1-MMP) and MMP-16 (MT3-MMP), and even higher levels of TIMP-1 and TIMP-2, but not TIMP-3 (Turner et al, 2010). Exposure of cells to IL-1 (10 ng/ml, 6 h) elicited 80-200-fold increases in mRNA levels of MMP-3 (stromelysin 1), MMP-9 (gelatinase B) and MMP-10 (stromelysin 2), and an 8-fold increase in MMP-1, while TIMP-2 mRNA levels were increased by a modest 2-fold (Turner et al, 2010).…”

“…In addition to their effects on MMPs, proinflammatory cytokines such as IL-1 may also be important stimulators of VEGF secretion and activity at the level of the fibroblast (Turner et al, 2010).…”

“…Human CF expressed relatively high basal levels of multiple ECM proteins under basal levels including collagens I, IV, V, VI, VIII, XII and XIV, laminins 2, β1 and 1 and fibronectin, but none of these were markedly affected by IL-1 stimulation over a 6 h period (Turner et al, 2010). It is possible that IL-1 may modulate expression of some ECM proteins at later time points, particularly as we have since observed a 20% reduction in COL1A1 mRNA expression 24 h after stimulation with 10 ng/ml IL-1; an inhibition that was not evident after 6 h (N.A.…”

“…We used a focused RT-PCR microarray to evaluate mRNA levels of structural ECM proteins, MMPs and TIMPs in cultured human CF and their modulation by IL-1 (Turner et al, 2010).…”