Rohraff, D. M. | bioRxiv Science

bioRxiv2020

Inhibition of histone readers bromodomain extra-terminal proteins alleviates scleroderma fibrosis

Binding of the bromodomain and extra-terminal domain proteins (BETs) to acetylated histone residues is critical for gene transcription. This study sought to determine the anti-fibrotic efficacy and potential mechanisms of BET inhibition in systemic sclerosis (SSc). Blockade of BETs was done using a pan BET inhibitor JQ1, BRD2 inhibitor BIC1, or BRD4 inhibitors AZD5153 or ARV825. BET inhibition, specifically BRD4 blockade, showed anti-fibrotic effects in an animal model of scleroderma and in patient-derived diffuse cutaneous (dc)SSc fibroblasts. Transcriptome analysis of JQ1-treated dcSSc fibroblasts revealed differentially expressed genes related to extracellular matrix, cell cycle, and calcium signaling. The anti-fibrotic effect of BRD4 inhibition was at least in part mediated by downregulation of Ca2+/calmodulin-dependent protein kinase II (CaMKII-) and reduction of intracellular calcium concentrations. These results suggest that targeting calcium pathways or BRD4 might be novel therapeutic approaches for progressive tissue fibrosis.

pharmacology and toxicology↗

bioRxiv2018

Inhibition of EZH2 ameliorates lupus-like disease in MRL/lpr mice

ObjectivesWe previously revealed a role for EZH2 in inducing pro-inflammatory epigenetic changes in lupus CD4+ T cells. In this study, we sought to determine if inhibiting EZH2 ameliorates lupus-like disease in MRL/lpr mice.\n\nMethodsEZH2 expression levels in multiple cell types in lupus patients were evaluated using flow cytometry and mRNA expression data. Inhibition of EZH2 in MRL/lpr mice was achieved by DZNep intraperitoneal administration using a preventative and a therapeutic treatment model. Effects of DZNep on animal survival, anti-dsDNA antibody production, proteinuria, renal histopathology, cytokine production, and T and B cell numbers and percentages were assessed.\n\nResultsEZH2 expression levels were increased in whole blood, neutrophils, monocytes, B cells, and CD4+ T cells in lupus patients. In MRL/lpr mice, inhibiting EZH2 with DZNep treatment before or after disease onset improved survival and significantly reduced anti-dsDNA antibody production. DZNep-treated mice displayed a significant reduction in renal involvement, splenomegaly, and lymphadenopathy.\n\nLymphoproliferation and numbers of double-negative T cells were significantly reduced in DZNep treated mice. Concentrations of circulating cytokines and chemokines, including TNF, IFN-{gamma}, CCL2, RANTES/CCL5, IL-10, KC/CXCL1, IL-12, IL-12p40 and MIP-1{beta}/CCL4 were decreased in DZNep treated mice.\n\nConclusionsZH2 is upregulated in multiple cell types in lupus patients. Therapeutic inhibition of EZH2 abrogates lupus-like disease in MRL/lpr mice, suggesting that EZH2 inhibitors may be repurposed as a novel therapeutic option in lupus patients.

immunology↗