Spiruchostatin A inhibits proliferation and differentiation of fibroblasts from patients with pulmonary fibrosis.

Abstract

Idiopathic pulmonary fibrosis (IPF) is a progressive scarring disorder characterized by the proliferation of interstitial fibroblasts and the deposition of extracellular matrix causing impaired gas exchange. Spiruchostatin A (SpA) is a histone deacetylase inhibitor (HDI) with selectivity toward Class I enzymes, which distinguishes it from other nonspecific HDIs that are reported to inhibit (myo)fibroblast proliferation and differentiation. Because the selectivity of HDIs may be important clinically, we postulated that SpA inhibits the proliferation and differentiation of IPF fibroblasts. Primary fibroblasts were grown from lung biopsy explants obtained from patients with IPF or from normal control subjects, using two-dimensional or three-dimensional culture models. The effect of SpA on fibroproliferation in serum-containing medium ± transforming growth factor (TGF)-β(1) was quantified by methylene blue binding. The acetylation of histone H3, the expression of the cell-cycle inhibitor p21(waf1), and the myofibroblast markers α-smooth muscle actin (α-SMA) and collagens I and III were determined by Western blotting, quantitative RT-PCR, immunofluorescent staining, or colorimetry. SpA inhibited the proliferation of IPF or normal fibroblasts in a time-dependent and concentration-dependent manner (concentration required to achieve 50% inhibition = 3.8 ± 0.4 nM versus 7.8 ± 0.2 nM, respectively; P < 0.05), with little cytotoxicity. Western blot analyses revealed that SpA caused a concentration-dependent increase in histone H3 acetylation, paralleling its antiproliferative effect. SpA also increased p21(waf1) expression, suggesting that direct cell-cycle regulation was the mechanism of inhibiting proliferation. Although treatment with TGF-β(1) induced myofibroblast differentiation associated with increased expression of α-SMA, collagen I and collagen III and soluble collagen release, these responses were potently inhibited by SpA. These data support the concept that bicyclic tetrapeptide HDIs merit further investigation as potential treatments for IPF.

• Authors: Elizabeth R Davies, Hans Michael Haitchi, Thomas H Thatcher, Patricia J Sime, R Matthew Kottmann, Arasu Ganesan, Graham Packham, Katherine M A O'Reilly, Donna E Davies
• Journal: American journal of respiratory cell and molecular biology (Am J Respir Cell Mol Biol) Vol. 46 Issue 5 Pg. 687-94 (May 2012) ISSN: 1535-4989 [Electronic] United States
• PMID: 22246864 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Histone Deacetylase Inhibitors
• Peptides, Cyclic
• spiruchostatin A

Topics

• Cell Differentiation (drug effects)
• Cell Proliferation (drug effects)
• Cells, Cultured
• Fibroblasts (cytology, drug effects)
• Fluorescent Antibody Technique, Indirect
• Histone Deacetylase Inhibitors (pharmacology)
• Humans
• Peptides, Cyclic (pharmacology)
• Polymerase Chain Reaction
• Pulmonary Fibrosis (pathology)