Histone deacetylase 7, a potential target for the antifibrotic treatment of systemic sclerosis

OBJECTIVE: We have recently shown a significant reduction in cytokine-induced transcription of type I collagen and fibronectin in systemic sclerosis (SSc) skin fibroblasts upon treatment with trichostatin A (TSA). Moreover, in a mouse model of fibrosis, TSA prevented the dermal accumulation of extracellular matrix. The purpose of this study was to analyze the silencing of histone deacetylase 7 (HDAC-7) as a possible mechanism by which TSA exerts its antifibrotic function. METHODS: Skin fibroblasts from patients with SSc were treated with TSA and/or transforming growth factor beta. Expression of HDACs 1-11, extracellular matrix proteins, connective tissue growth factor (CTGF), and intercellular adhesion molecule 1 (ICAM-1) was analyzed by real-time polymerase chain reaction, Western blotting, and the Sircol collagen assay. HDAC-7 was silenced using small interfering RNA. RESULTS: SSc fibroblasts did not show a specific pattern of expression of HDACs. TSA significantly inhibited the expression of HDAC-7, whereas HDAC-3 was up-regulated. Silencing of HDAC-7 decreased the constitutive and cytokine-induced production of type I and type III collagen, but not fibronectin, as TSA had done. Most interestingly, TSA induced the expression of CTGF and ICAM-1, while silencing of HDAC-7 had no effect on their expression. CONCLUSION: Silencing of HDAC-7 appears to be not only as effective as TSA, but also a more specific target for the treatment of SSc, because it does not up-regulate the expression of profibrotic molecules such as ICAM-1 and CTGF. This observation may lead to the development of more specific and less toxic targeted therapies for SSc

The Protease Inhibitor Alpha-2-Macroglobuline-Like-1 Is the p170 Antigen Recognized by Paraneoplastic Pemphigus Autoantibodies in Human

Paraneoplastic pemphigus (PNP) is a devastating autoimmune blistering disease, involving mucocutaneous and internal organs, and associated with underlying neoplasms. PNP is characterized by the production of autoantibodies targeting proteins of the plakin and cadherin families involved in maintenance of cell architecture and tissue cohesion. Nevertheless, the identity of an antigen of Mr 170,000 (p170), thought to be critical in PNP pathogenesis, has remained unknown

Innate immunity, epigenetics and autoimmunity in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease characterized by the progressive and irreversible destruction of joints. RA remains an incurable condition, although a new class of drugs, biologicals, have made a major breakthrough in targeting and/or eliminating the immune cells, including T cells, B cells and monocytes/macrophages from the joints. That we cannot (yet?) cure the disease is most likely due to the lack of therapeutic targeting the endogenously activated RA synovial fibroblasts (RASF). Most interestingly, RASF express Toll-like receptors (TLRs) 1-6 rendering them prone to activation by exogenous and endogenous TLR ligands and resulting in the production of numerous powerful chemokines and cytokines. These factors are responsible for the repopulation of immune cells in the joints after ceasing cell depleting therapies. To characterize the molecular mechanisms of synovial activation, a new approach studying the epigenetic characteristics of RASF has been recently undertaken. Thereby, the pattern of histone acetylation, DNA methylation and gene expression regulating microRNA are being explored. Since auto-antibodies have the most predictive and diagnostic value for RA, it is challenging to study more comprehensively the contribution of auto-antibodies to the disease. A new screening technique, serological analysis of recombinant human cDNA expression library (SEREX), adapted from cancer research allowed for the identification of novel auto-antibodies in RA, including anti-serpin E2 auto-antibodies. The serpin E2 auto-antibodies were found to inhibit the activity of serpin E2 and have potentially a functional role in the disease. The recent findings in the field of innate immunity, epigenetics and autoimmunity related to the pathogenesis of RA are in the scope of this review

Epigenetics in the pathogenesis of RA

Epigenetic modifications can stably alter gene expression and have been shown to be important in the maintenance of cell type-specific functions as well as in cell differentiation, e.g., in T and B cell maturation. In RA, alterations in DNA methylation, histone modifications, and microRNA expression have been found in immune as well as in stromal cells. These changes in the epigenome in RA patients influence key inflammatory and matrix-degrading pathways and are suspected to play a major role in the pathogenesis of RA. In this manuscript, we explain the basic mechanisms of epigenetics, review studies that analyzed epigenetic changes in RA, and assess their potential as therapeutic targets