trichostatin-a and Osteoarthritis

The histone deacetylase inhibitor trichostatin A (TSA) has been demonstrated to alleviate certain symptoms associated with osteoarthritis (OA). However, the exact mechanisms underlying this protective effect remain to be elucidated. The present study therefore examined the effects of TSA on the expression levels of interleukin‑1β (IL‑1β)-induced matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases-1 (TIMP-1) in vitro and in vivo. In vitro, reverse transcription‑quantitative polymerase chain reaction was performed to investigate alterations in mRNA expression levels in TSA-treated chondrocytes in the presence or absence of IL‑1β; in addition, protein expression and acetylation levels were assessed by western blotting. In vivo, TSA was administered to rats by intra‑articular injection, following which the mRNA and protein expression levels were analyzed. In addition, macroscopic and histological observations were conducted. Chondrocytes treated with IL‑1β demonstrated increased mRNA and protein expression levels of MMP‑1, MMP‑3 and MMP-13, and decreased expression levels of TIMP‑1 mRNA and protein; these alterations were significantly attenuated by TSA treatment. In addition, increased MMPs and decreased TIMP‑1 expression levels were observed in vivo in the OA rat model. TSA treatment demonstrated in vivo efficacy through the attenuation of various OA‑associated molecular and physiological changes. Taken together, the results of the present study suggest that TSA has potential therapeutic value for the treatment of OA.

Topics: Acetylation; Animals; Cartilage, Articular; Chondrocytes; Disease Models, Animal; Female; Gene Expression; Histone Deacetylase Inhibitors; Hydroxamic Acids; Male; Matrix Metalloproteinases; Osteoarthritis; Rats; RNA, Messenger; Tissue Inhibitor of Metalloproteinase-1

In rheumatoid arthritis (RA), synovial fibroblasts (RA-SFs) accumulate in affected joints, where they play roles in inflammation and joint destruction. RA-SFs exhibit tumor-like proliferation and are resistant to apoptosis. Although RA-SF activation is well described, negative regulators of RA-SF activation are unknown. We previously reported that histone deacetylase (HDAC) inhibitors facilitate apoptosis in RA-SFs. Here we found that RA-SFs treated with the HDAC inhibitor Trichostatin A (TSA) exhibited an upregulation of the immediate early response gene X-1 (IEX-1). IEX-1 has roles in apoptosis sensitivity, cell-cycle progression, and proliferation, and is reported to be involved in immune responses, inflammation, and tumorigenesis, and to have anti-arthritic properties. To investigate IEX-1's role in RA-SFs, we used in vitro-cultured synovial fibroblasts from RA and osteoarthritis (OA) patients. We confirmed that TSA upregulated the IEX-1 protein and mRNA expressions in RA-SFs by western blotting and quantitative RT-PCR. Inhibiting HDAC1, 2, and 3 (but not 6 or 8) also upregulated IEX-1. The IEX-1 mRNA levels were higher in RA-SFs than in OA-SFs, and were further upregulated in RA-SFs by the pro-inflammatory cytokines TNFα and IL-1β. The staining of surgical specimens showed that IEX-1 was present in the pannus from affected RA joints. Si-RNA-mediated IEX-1 knockdown upregulated the lipopolysaccharide (LPS)-induced expression of TNFα and various chemokine mRNAs, indicating that IEX-1 downregulates TNFα and chemokines. Furthermore, apoptosis analysis showed that IEX-1 knockdown protected RA-SFs from apoptosis induced by TSA or by an anti-Fas mAb, indicating that IEX-1 is pro-apoptotic in RA-SFs. Collectively, our results showed that IEX-1 is induced by TNFα and IL-1β in RA-SFs, in which it suppresses TNFα and chemokine production and induces apoptosis; thus, IEX-1 negatively regulates RA-SF activation. Further investigation of IEX1's functions in RA-SFs may lead to new therapeutic approaches for RA.

Topics: Apoptosis; Apoptosis Regulatory Proteins; Arthritis, Rheumatoid; Cells, Cultured; Chemokines; Fibroblasts; Humans; Hydroxamic Acids; Membrane Proteins; Osteoarthritis; Synovial Membrane; Tumor Necrosis Factor-alpha; Up-Regulation

Osteoarthritis (OA) is a common joint disease that can cause gradual disability among the aging population. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a key transcription factor that regulates the expression of phase II antioxidant enzymes that provide protection against oxidative stress and tissue damage. The use of histone deacetylase inhibitors (HDACi) has emerged as a potential therapeutic strategy for various diseases. They have displayed chondroprotective effects in various animal models of arthritis. Previous studies have established that Nrf2 acetylation enhances Nrf2 functions. Here we explore the role of Nrf2 in the development of OA and the involvement of Nrf2 acetylation in HDACi protection of OA.. Two OA models-monosodium iodoacetate (MIA) articular injection and destabilization of the medial meniscus (DMM)-were used with wild-type (WT) and Nrf2-knockout (Nrf2-KO) mice to demonstrate the role of Nrf2 in OA progression. A pan-HDACi, trichostatin A (TSA), was administered to examine the effectiveness of HDACi on protection from cartilage damage. The histological sections were scored. The expression of OA-associated matrix metalloproteinases (MMPs) 1, 3, and 13 and proinflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 were assayed. The effectiveness of HDACi on OA protection was compared between WT and Nrf2-KO mice.. Nrf2-KO mice displayed more severe cartilage damage in both the MIA and DMM models. TSA promoted the induction of Nrf2 downstream proteins in SW1353 chondrosarcoma cells and in mouse joint tissues. TSA also reduced the expression of OA-associated proteins MMP1, MMP3, and MMP13 and proinflammatory cytokines TNF-α, IL-1β, and IL-6. TSA markedly reduced the cartilage damage in both OA models but offered no significant protection in Nrf2-KO mice.. Nrf2 has a major chondroprotective role in progression of OA and is a critical molecule in HDACi-mediated OA protection.

Topics: Animals; Arthritis, Experimental; Blotting, Western; Cartilage, Articular; Cell Line; Chondrocytes; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Male; Mice; Mice, Knockout; NF-E2-Related Factor 2; Osteoarthritis; Polymerase Chain Reaction

This study investigated the effects of the histone deacetylase (HDAC) inhibitor trichostatin A (TSA) on cartilage degradation in an experimental model of osteoarthritis (OA). Thirty-two male New Zealand rabbits underwent unilateral anterior cruciate ligament transection (ACLT) on left knee joints to induce OA and were randomly divided into two groups (n = 16), the TSA group was injected intra-articularly with 0.3 ml TSA [250 ng/ml in the dimethylsulphoxide (DMSO)], the OA group received DSMO since 4 weeks after operation once a week for 5 weeks. Rabbits were killed seven days after the last injection. Left knee cartilage was harvested for morphological, histological and genetic analysis. Another ten rabbits were used for normal control and received no injection. The TSA group showed less cartilage degradation as compared to the OA group assessed by morphological and histological evaluation. Gene expression of matrix metalloproteinase-1 (MMP-1), MMP-3, MMP-13, and interleukin-1 (IL-1) was increased significantly in the OA group compared to the normal group. The elevated expression was reduced by TSA. Our results suggest that TSA could be considered as a potential agent for treatment for OA.

Topics: Animals; Cartilage, Articular; Femur; Histone Deacetylase Inhibitors; Hydroxamic Acids; Interleukin-1; Male; Matrix Metalloproteinases; Osteoarthritis; Rabbits

To investigate whether epigenetic mechanisms can regulate leptin's expression and affect its downstream targets as metalloproteinases 3,9,13 in osteoarthritic chondrocytes.. DNA methylation in leptin promoter was measured by DNA bisulfite sequencing, and mRNA expression levels were measured by real-time quantitative PCR in osteoarthritic as well as in normal cartilage. Osteoarthritic articular cartilage samples were obtained from two distinct locations of the knee (n = 15); from the main defective area of maximum load (advanced osteoarthritis (OA)) and from adjacent macroscopically intact regions (minimal OA). Using small interference RNA, we tested if leptin downregulation would affect matrix metalloproteinase (MMP)-13 activity. We also evaluated the effect of the demethylating agent, 5'-Aza-2-deoxycytidine (AZA) and of the histone deacetylase inhibitor trichostatin A (TSA) on leptin expression in chondrocyte cultures. Furthermore, we performed chromatin immunoprecipitation in leptin's promoter area.. We found a correlation between leptin expression and DNA methylation and also that leptin controls MMP-13 activity in chondrocytes. Leptin's downregulation with small interference RNA inhibited MMP-13 expression dramatically. After 5-AZA application in normal chondrocytes, leptin's methylation was decreased, while its expression was upregulated, and MMP-13 was activated. Furthermore, TSA application in normal chondrocyte cultures increased leptin's expression. Also, chromatin immunoprecipitation in leptin's promoter after TSA treatment revealed that histone H3 lysines 9 and 14 were acetylated.. We found that epigenetic mechanisms regulate leptin's expression in chondrocytes affecting its downstream target MMP-13. Small interference RNA against leptin deactivated directly MMP-13, which was upregulated after leptin's epigenetic reactivation, raising the issue of leptin's therapeutic potential for osteoarthritis.

Topics: Acetylation; Adult; Aged; Aged, 80 and over; Analysis of Variance; Azacitidine; Blotting, Western; Cartilage, Articular; Case-Control Studies; Chondrocytes; Decitabine; DNA Methylation; DNA Modification Methylases; Female; Gene Expression; Gene Expression Regulation; Histone Deacetylase Inhibitors; Histones; Humans; Hydroxamic Acids; Knee Joint; Leptin; Male; Matrix Metalloproteinase 13; Matrix Metalloproteinase 3; Matrix Metalloproteinase 9; Middle Aged; Osteoarthritis; Promoter Regions, Genetic; RNA Interference; RNA, Small Interfering

Histone acetylation/deacetylation has a critical role in the regulation of transcription by altering the chromatin structure.. To analyse the effect of trichostatin A (TSA), a streptomyces metabolite which specifically inhibits mammalian histone deacetylases, on TRAIL-induced apoptosis of rheumatoid arthritis synovial fibroblasts (RASF).. Apoptotic cells were detected after co-treatment of RASF with TRAIL (200 ng/ml) and TSA (0.5, 1, and 2 micromol/l) by flow cytometry using propidium iodide/annexin-V-FITC staining. Cell proliferation was assessed using the MTS proliferation test. Induction of the cell cycle inhibitor p21Waf/Cip1 by TSA was analysed by western blot. Expression of the TRAIL receptor-2 (DR5) on the cell surface of RASF was analysed by flow cytometry. Levels of soluble TRAIL were measured in synovial fluid of patients with RA and osteoarthritis (OA) by ELISA.. Co-treatment of the cells with TSA and TRAIL induced cell death in a synergistic and dose dependent manner, whereas TRAIL and TSA alone had no effect or only a modest effect. RASF express DR5 (TRAIL receptor 2), but treatment of the cells with TSA for 24 hours did not change the expression level of DR5, as it is shown for cancer cells. TSA induced cell cycle arrest in RASF through up regulation of p21Waf1/Cip1. Levels of soluble TRAIL were significantly higher in RA than in OA synovial fluids.. Because TSA sensitises RASF for TRAIL-induced apoptosis, it is concluded that TSA discloses sensitive sites in the cascade of TRAIL signalling and may represent a new principle for the treatment of RA.

Topics: Aged; Apoptosis; Apoptosis Regulatory Proteins; Arthritis, Rheumatoid; Blotting, Western; Cells, Cultured; Cyclin-Dependent Kinase Inhibitor p21; Dose-Response Relationship, Drug; Drug Synergism; Female; Fibroblasts; Flow Cytometry; Humans; Hydroxamic Acids; Male; Membrane Glycoproteins; Middle Aged; Osteoarthritis; Synovial Membrane; TNF-Related Apoptosis-Inducing Ligand; Tumor Necrosis Factor-alpha