Effects of HDAC4 on IL-1β-induced matrix metalloproteinase expression regulated partially through the WNT3A/β-catenin pathway

Background::Histone deacetylase 4(HDAC4)regulates chondrocyte hypertrophy and bone formation.The aim of the present study was to explore the effects of HDAC4 on Interleukin 1 beta(IL-1β)-induced chondrocyte extracellular matrix degradation and whether it is regulated through the WNT family member 3A(WNT3A)/β-catenin signaling pathway.Methods::Primary chondrocytes(CC)and human chondrosarcoma cells(SW1353 cells)were treated with IL-1βand the level of HDAC4 was assayed using Western blotting.Then,HDAC4 expression in the SW1353 cells was silenced using small interfering RNA to detect the effect of HDAC4 knockdown on the levels of matrix metalloproteinase 3(MMP3)and MMP13 induced by IL-1β.After transfection with HDAC4 plasmids,the overexpression efficiency was examined using Real-time quantitative polymerase chain reaction(qRT-PCR)and the levels of MMP3 and MMP13 were assayed using Western blotting.After incubation with IL-1β,the translocation ofβ-catenin into the nucleus was observed using immunofluorescence staining in SW1353 cells to investigate the activation of the WNT3A/β-catenin signaling pathway.Finally,treatment with WNT3A and transfection with glycogen synthase kinase 3 beta(GSK3β)plasmids were assessed for their effects on HDAC4 levels using Western blotting.Results::IL-1βdownregulated HDAC4 levels in chondrocytes and SW1353 cells.Furthermore,HDAC4 knockdown increased the levels of MMP3 and MMP13,which contributed to the degradation of the extracellular matrix.Overexpression of HDAC4 inhibited IL-1β-induced increases in MMP3 and MMP13.IL-1βupregulated the levels of WNT3A,and WNT3A reduced HDAC4 levels in SW1353 cells.GSK-3βrescued IL-1β-induced downregulation of HDAC4 in SW1353 cells.Conclusion::HDAC4 exerted an inhibitory effect on IL-1β-induced extracellular matrix degradation and was regulated partially by the WNT3A/β-catenin signaling pathway.

Effects of (-)-epigallocatechin-3-gallate on expression of matrix metalloproteinase-1 and tissue inhibitor of metalloproteinase-1 in fibroblasts irradiated with ultraviolet A

Background It is known that ultraviolet irradiation can affect cellular function through a number of signaling pathways ( ) epigallocatechin 3 gallate (EGCG) is the major effective component in green tea and can offer protection from ultraviolet induced damage In this study, we investigated the protective mechanism of EGCG on human dermal fibroblasts damaged by ultraviolet A (UVA) in vitro Methods Transcription factor Jun protein levels were measured by Western blot Matrix metalloproteinase 1 (MMP 1) and tissue inhibitor of metalloproteinase 1 (TIMP 1) mRNA were studied by reverse transcription polymerase chain reaction (RT PCR) analysis in conjunction with computer assisted image analysis MMP 1 and TIMP 1 proteins were quantified by enzyme linked immunosorbent assay (ELISA) Results EGCG decreased transcription activity of Jun protein after induction by UVA Both the mRNA and protein levels of MMP 1 were increased by UVA irradiation, while no significant changes were observed in TIMP 1 levels The ratio of MMP 1 to TIMP 1 showed statistically significant differences compared with the control EGCG decreased the ratio of MMP 1 to TIMP 1 by inhibiting UVA induced MMP 1 expression ( P <0 05) Conclusion EGCG can protect human fibroblasts against UVA damage by downregulating the transcription activity of Jun protein and the expression of MMP 1 The ratio of MMP 1 to TIMP 1, rather than the levels of MMP 1 or TIMP 1 alone, may play a significant role in human skin photodamage