Adiponectin Upregulates Prolyl-4-Hydroxylase α1 Expression in Interleukin 6-Stimulated Human Aortic Smooth Muscle Cells by Regulating ERK 1/2 and Sp1

Adiponectin is an anti-atherogenic adipokine that inhibits the development of plaque by mechanisms that are not completely understood. Extracellular matrix (ECM) may have a role in the pathogenesis of atherosclerosis. We explored the effect and mechanisms of adiponectin on the synthesis of prolyl-4-hydroxylase (P4H) in interleukin 6 (IL-6)-stimulated human aortic smooth muscle cells (HASMCs). P4Hα1 mRNA level was quantified by RT-PCR, the protein levels of phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2) and P4Hα1 were quantified by western blot analysis, and activation of specific protein 1 (Sp1) was determined by electrophoretic mobility shift assay and subcellular localization of Sp1 by immunofluorescence analysis. Adiponectin significantly increased P4Hα1 mRNA and protein levels in IL-6-stimulated HASMCs in a dose- and time-dependent manner. As well, ERK1/2 and Sp1 played a crucial role in the effect of adiponectin upregulating P4Hα1 expression in IL-6-stimulated HASMCs. Adiponectin abrogated the effects of IL-6 on collagen III level, which may indicate that P4Hα1 is essential for folding the procollagen polypeptide chains into stabilized collagen. Adiponectin attenuates IL-6–inhibited P4Hα1 synthesis and stabilizes collagen formation in HASMCs through a Sp1-ERK1/2-P4Hα1-dependent pathway

Overexpression of cathepsin K during silica-induced lung fibrosis and control by TGF-β

BACKGROUND: Lung fibrosis is characterized by tissue remodeling resulting from an imbalance between synthesis and degradation of extracellular organic matrices. To examine whether cathepsin(s) (Cat) are important in the development of pulmonary fibrosis, we assessed the expression of four Cat known for their collagenolytic activity in a model of silica-induced lung fibrosis. METHODS: Different strains of mice were transorally instilled with 2.5 mg crystalline silica or other particles. Cat expression (Cat K, S, L and B) was quantified in lung tissue and isolated pulmonary cells by quantitative RT-PCR. In vitro, we assessed the effect of different cytokines, involved in lung inflammatory and fibrotic responses, on the expression of Cat K by alveolar macrophages and fibroblasts. RESULTS: In lung tissue, Cat K transcript was the most strongly upregulated in response to silica, and this upregulation was intimately related to the fibrotic process. In mouse strains known for their differential response to silica, we showed that the level of Cat K expression following silica treatment was inversely related to the level of TGF-β expression and the susceptibility of these strains to develop fibrosis. Pulmonary macrophages and fibroblasts were identified as Cat K overproducing cells in the lung of silicotic mice. In vitro, Cat K was downregulated in mouse and human lung fibroblasts by the profibrotic growth factor TGF-β1. CONCLUSION: Altogether, these data suggest that while Cat K may contribute to control lung fibrosis, TGF-β appears to limit its overexpression in response to silica particles

Matrix metalloproteinase inhibitors reduce collagen gel contraction and alpha-smooth muscle actin expression by periodontal ligament cells.

Contains fulltext : 79864.pdf (publisher's version ) (Closed access)BACKGROUND AND OBJECTIVE: Orthodontic tooth movement requires remodeling of the periodontal tissues. The matrix metalloproteinases (MMPs) degrade the extracellular matrix components of the periodontal ligament, while the tissue inhibitors of metalloproteinases (TIMPs) control their activity. Synthetic MMP inhibitors have been developed to inhibit MMP activity. In this study, periodontal ligament cells in contracting collagen gels served as a model for enhanced periodontal remodeling. The effect of MMP inhibitors on gel contraction and on MMP and TIMP expression was analyzed. MATERIAL AND METHODS: Human periodontal ligament cells were cultured in three-dimensional collagen gels and incubated with the MMP inhibitors BB94, CMT-3, doxycycline and Ilomastat. Gel contraction was determined using consecutive photographs. The relative amounts of MMPs and TIMPs were analyzed using substrate zymography and mRNA expression using quantitative polyermase chain reaction. RESULTS: All MMP inhibitors reduced MMP activity to about 20% of the control activity. They all reduced contraction, but CMT-3 and doxycycline had the strongest effect. These inhibitors also reduced MMP-2, MMP-3 and alpha-smooth muscle actin mRNA expression. The expression of MMP-1 mRNA seemed to be increased by CMT-3. No effects were found on the amounts of MMPs and TIMPs. CONCLUSION: Synthetic MMP inhibitors strongly reduced gel contraction by periodontal ligament cells. This was primarily caused by an inhibitory effect on MMP activity, which reduces matrix remodeling. In addition, alpha-smooth muscle actin expression was reduced by CMT-3 and doxycycline, which limits the contractile activity of the fibroblasts