The histone demethylase Jumonji domain-containing protein 3 (JMJD3) regulates fibroblast activation in systemic sclerosis

Abstract

Abstract:Objectives Systemic sclerosis (SSc) fibroblasts remain activated even in the absence of exogenous stimuli. Epigenetic alterations are thought to play a role for this endogenous activation. Trimethylation of histone H3 on lysine 27 (H3K27me3) is regulated by Jumonji domain-containing protein 3 (JMJD3) and ubiquitously transcribed tetratricopeptide repeat on chromosome X (UTX) in a therapeutically targetable manner. The aim of this study was to explore H3K27me3 demethylases as potential targets for the treatment of fibrosis.Methods JMJD3 was inactivated by small interfering RNA-mediated knockdown and by pharmacological inhibition with GSKJ4. The effects of targeted inactivation of JMJD3 were analysed in cultured fibroblasts and in the murine models of bleomycin-induced and topoisomerase-I (topoI)-induced fibrosis. H3K27me3 at the FRA2 promoter was analysed by ChIP. ResultsThe expression of JMJD3, but not of UTX, was increased in fibroblasts in SSc skin and in experimental fibrosis in a transforming growth factor beta (TGFβ)-dependent manner. Inactivation of JMJD3 reversed the activated fibroblast phenotype in SSc fibroblasts and prevented the activation of healthy dermal fibroblasts by TGFβ. Pharmacological inhibition of JMJD3 ameliorated bleomycininduced and topoI-induced fibrosis in well-tolerated doses. JMJD3 regulated fibroblast activation in a FRA2-dependent manner: Inactivation of JMJD3 reduced the expression of FRA2 by inducing accumulation of H3K27me3 at the FRA2promoter. Moreover, the antifibrotic effects of JMJD3 inhibition were reduced on knockdown of FRA2. ConclusionWe present first evidence for a deregulation of JMJD3 in SSc. JMJD3 modulates fibroblast activation by regulating the levels of H3K27me3 at the promoter of FRA2. Targeted inhibition of JMJD3 limits the aberrant activation of SSc fibroblasts and exerts antifibrotic effects in two murine models.

Evolving insights into the cellular and molecular pathogenesis of fibrosis in systemic sclerosis

“…SSc fibroblasts demonstrate global alterations in methylation, particularly the hypomethylation of genes including ITGA9, ADAM12, COL23A1, COL4A2 MYO1E, and the RUNX family of transcription factors [18]. Functionally, epigenetic alteration of histone demethylases such as MeCP2 and JMJD3 regulate epigenetic modifications on transcription factor promoters and determine fibroblasts' fibrogenic potential [19,20]. The Wnt pathway genes DKK1 and SFRP1 are also hypomethylated in both SSc fibroblasts and peripheral blood mononuclear cells (PBMCs).…”

Unraveling SSc Pathophysiology; The Myofibroblast

“…Because the activated phenotype of SSc (myo) fibroblasts persists ex vivo , e.g., during cell culture, epigenetic changes most likely play an important role in this phenotype. For example, recent research has shown that in SSc skin fibroblasts, expression of the histone demethylase Jumonji domain-containing protein 3 (JMJD3) is increased ( 99 ). This histone demethylase removes the so-called H3K27me3 mark from histones, and this mark can repress expression of pro-fibrotic genes such as collagen type I in fibroblasts ( 100 ).…”

“…Furthermore, pharmacological inhibition of H3K27 trimethylation induces skin fibrosis and aggravates pathology in bleomcyin induced skin fibrosis ( 100 ). A key target which is activated by JMJD3 is Fos-related antigen 2 (Fra-2) ( 99 ). This transcription factor has been identified as an important regulator of extracellular matrix production in skin fibroblasts; transgenic overexpression of Fra-2 results in increased dermal thickness and myofibroblast formation and is a mouse model for SSc ( 101 ), whereas knockdown of Fra-2 reduces both TGFβ- and PDGF-induced collagen production in primary skin fibroblasts of SSc patients ( 102 ).…”

JMJD3 in the regulation of human diseases

“…It was indicated that JMJD3 promoted fibroblast activation via enhancing FRA2 expression. Special silencing of JMJD3 inhibited abnormal activation of SSc fibroblasts and exert effective anti-fibrotic effects in mouse models (Bergmann et al 2018). In osteoarthritis, TGF-β enhanced the expression of JMJD3 and increased JMJD3 targeted osteoarthritis (OA)-associated genes, and thus enhanced chondrocyte hypertrophy and matrix destruction, leading to OA progression (Yapp et al 2016).…”