Tumor necrosis factor-?-accelerated degradation of type I collagen in human skin is associated with elevated matrix metalloproteinase (MMP)-1 and MMP-3 ex vivo.

ABSTRACT: Tumor necrosis factor (TNF)-? induces matrix metalloproteinases (MMPs) that may disrupt skin integrity. We have investigated the effects and mechanisms of exogenous TNF-? on collagen degradation by incubating human skin explants in defined serum-free media with or without TNF-? (10ng/ml) in the absence or presence of the nonselective MMP inhibitor GM6001 for 8 days. The basal culture conditions promoted type I collagen catabolism that was accelerated by TNF-? (p<0.005) and accomplished by MMPs (p<0.005). Levels of the collagenases MMP-8 and MMP-13 were insignificant and neither MMP-2 nor MMP-14 were associated with increased collagen degradation. TNF-? increased secretion of MMP-1 (p<0.01) but had no impact on MMP-1 quantities in the tissue. Immunohistochemical analysis confirmed similar tissue MMP-1 expression with or without TNF-? with epidermis being the major source of MMP-1. Increased tissue-derived collagenolytic activity with TNF-? exposure was blocked by neutralizing MMP-1 monoclonal antibody and was not due to down-regulation of tissue inhibitor of metalloproteinase-1. TNF-? increased production (p<0.01), tissue levels (p<0.005) and catalytic activity of the endogenous MMP-1 activator MMP-3. Type I collagen degradation correlated with MMP-3 tissue levels (rs=0.68, p<0.05) and was attenuated with selective MMP-3 inhibitor. Type I collagen formation was down-regulated in cultured compared with native skin explants but was not reduced further by TNF-?. TNF-? had no significant effect on epidermal apoptosis. Our data indicate that TNF-? augments collagenolytic activity of MMP-1, possibly through up-regulation of MMP-3 leading to gradual loss of type I collagen in human skin.

SUBMITTER: Agren MS 

PROVIDER: S-EPMC4300401 | biostudies-literature | 2015 Jan

REPOSITORIES: biostudies-literature