Inhibition of histone deacetylase 2 mitigates profibrotic TGF-β1 responses in fibroblasts derived from Peyronie's plaque

Abstract

Epigenetic modifications, such as histone acetylation/deacetylation, have been shown to play a role in the pathogenesis of fibrotic disease. Peyronie's disease (PD) is a localized fibrotic process of the tunica albuginea, which leads to penile deformity. This study was undertaken to determine the anti-fibrotic effect of small interfering RNA (siRNA)-mediated silencing of histone deacetylase 2 (HDAC2) in primary fibroblasts derived from human PD plaque. PD fibroblasts were pre-treated with HDAC2 siRNA and then stimulated with transforming growth factor-b1 (TGF-b1). Protein was extracted from treated fibroblasts for Western blotting and the membranes were probed with antibody to phospho-Smad2/Smad2, phospho-Smad3/Smad3, smooth muscle a-actin and extracellular matrix proteins, including plasminogen activator inhibitor-1, fibronectin, collagen I and collagen IV. We also performed immunocytochemistry to detect the expression of extracellular matrix proteins and to examine the effect of HDAC2 siRNA on the TGF-b1-induced nuclear translocation of Smad2/3 in fibroblasts. Knockdown of HDAC2 in PD fibroblasts abrogated TGF-b1-induced extracellular matrix production by blocking TGF-b1-induced phosphorylation and nuclear translocation of Smad2 and Smad3, and by inhibiting TGF-b1-induced transdifferentiation of fibroblasts into myofibroblasts. Decoding the individual function of the HDAC isoforms by use of siRNA technology, preferably siRNA for HDAC2, may lead to the development of specific and safe epigenetic therapies for PD.

The Genetic Basis of Peyronie Disease: A Review

“…In order to determine if inhibition of HDAC2 would limit the profibrotic response to TGFβ signaling in human PD plaques, Ryu et al used RNA interference (RNAi) via small interfering RNA (siRNA) targeting HDAC2, comparing PD plaque-derived fibroblasts to control fibroblasts transfected with nonspecific scramble siRNA. 94 Protein expression levels of plasminogen activator inhibitor 1 (PAI1), fibronectin, collagens I and IV, smooth muscle α-actin, and HDAC2 were assessed using Western blot following stimulation with TGFβ. The authors observed a 60% reduction in HDAC2 expression in PD plaque-derived fibroblasts transfected with the HDAC2-targeted siRNA, with similar reductions in expression of PAI1, fibronectin, collagens I and IV, and smooth muscle α-actin.…”

Peyronie's Disease and Autoimmunity—A Real-Life Clinical Study and Comprehensive Review

“…Alterations of apoptosis gene expression observed in PD plaques have been allegedly involved in the fibrosing process following a status of local inflammation [21], as they may eventually result in abnormally prolonged fibroblast activity and survival. Likewise, epigenetic modifications seem to play a role fostering fibrosis [22]. Preclinical data also showed how local antigen‐driven immune response at the level of the tunica albuginea, such as the case of a rat tunica albuginea allograft, induces similar alterations to those observed in PD plaques [23].…”

Metal-dependent Deacetylases: Cancer and Epigenetic Regulators

“…39 Recent studies have also shown that both HDAC2 silencing and inhibition induce regression of fibrotic formation in Peyronie’s disease models. 40,41 Using mutant fibroblasts that are HDAC2-deficient, Zimmerman and collaborators demonstrated a lack of response to insulin-like growth factors (IGFs) when compared to wild type cells, showing a potential link between HDACs and IGFs. 34 Mice models lacking HDAC1 and with a single HDAC2 allele develop a lethal pathology within 3 months, likely due to neoplastic transformation of immature T cells.…”