Background Osteoarthritis is a main cause of deformity in aging people. The chondrogenesis of human adipose-derived stem cells (hADSCs) has a positive effect on the cure of osteoarthritis. However, the regulatory mechanism of hADSC chondrogenesis still needs further exploration. This research investigates the role of interferon regulatory factor 1 (IRF1) in the chondrogenesis of hADSCs. Methods hADSCs were purchased and cultured. The interaction between IRF1 and hypoxia inducible lipid droplet associated (HILPDA) was predicted by bioinformatics analysis, and verified through dual-luciferase reporter and chromatin immunoprecipitation assays. The expressions of IRF1 and HILPDA in osteoarthritis cartilage samples were measured through qRT-PCR. After hADSCs were transfected or further induced for chondrogenesis, the chondrogenesis was visualized by Alcian blue staining, and the expressions of IRF1, HILPDA and chondrogenesis-related factors (SOX9, Aggrecan , COL2A1, MMP13, MMP3) were determined through qRT-PCR or Western blot . Results HILPDA bound to IRF1 in hADSCs. IRF1 and HILPDA levels were up-regulated during the chondrogenesis of hADSCs. Overexpressions of IRF1 and HILPDA promoted the chondrogenesis of hADSCs with the up-regulation of SOX9 , Aggrecan and COL2A1 and the down-regulation of MMP13 and MMP3 ; however, IRF1 silencing generated the opposite effects. Besides, HILPDA overexpression reversed the effects of IRF1 silencing on inhibiting chondrogenesis of hADSCs and regulating the expressions of chondrogenesis-related factors. Conclusion IRF1 promotes the chondrogenesis of hADSCs through up-regulating HILPDA level, providing novel biomarkers for treating osteoarthritis.
He Yu-Kun,Cen Xiao-tong,Liu Shuang-shuang,Lu Hua-ding,He Chun-nian
Background Paeonia suffruticosa is an important traditional Chinese herb used to treat osteoarthritis (OA) and oligostilbenes are the main active ingredient of the seeds of P. suffruticosa. The monomer trans-resveratrol of this species was demonstrated to have chondroprotective effects as a lead compound for the treatment of osteoarthritis, but it has not been applied due to its low efficacy.Methods Oligostilbenes were isolated by chromatography and were identified by NMR and HPLC. A rabbit osteoarthritis chondrocyte model was induced by interleukin-1β and was treated with individual drugs to systematically evaluate their effects. Cell Counting Kit 8 was used to test their effects on cell viability, calculate EC50 and plot a dose–response curve.Their effects on apoptosis were analyzed by Annexin V and PI staining, and the expression of chondrocyte-specific genes COL2A1, MMP13 and SOX9 was evaluated by real-time PCR.Results Paeonia suffruticosa seed extract could promote the cell viability of rabbit OA chondrocytes at low concentration and then ten oligostilbenes were isolated from it. Trans-oligostilbenes were better than their cis-forms, trimers and dimers were better than monomers for promoting the cell viability of rabbit osteoarthritis chondrocytes. None of the oligostilbenes was more effective than seed extract at the appropriate concentration; 1 μM oligostilbenes all showed various anti-apoptotic effects. Trans-gnetin H showed the best effect on proliferation and inhibition of MMP13 expression on OA chondrocytes, while trans-viniferin was most effective in promoting the expression of COL2A1 and SOX9.Conclusion sTen oligostilbenes from P. suffruticosa seed all have certain protective effects on OA chondrocytes at low concentration. The trans-viniferin and some trimers have the potential to be further developed for the treatment of osteoarthritis because they were more effective than resveratrol and diacerein. The synergistic effect that may exist between oligostilbenes also warrants further research.