Suberoylanilide hydroxamic acid: a potential epigenetic therapeutic agent for lung fibrosis?

Pulmonary fibrosis represents a fatal stage of interstitial lung diseases of known and idiopathic aetiology. No effective therapy is currently available. Based on an indication-discovery approach we present novel in vitro evidence that the histone deacetylases inhibitor suberoylanilide hydroxamic acid (SAHA), an FDA approved anti-cancer drug, has antifibrotic and anti-inflammatory potential. Human lung fibroblasts (fetal, adult and idiopathic adult pulmonary fibrosis) were treated with transforming growth factor (TGF)-beta 1 with or without SAHA. Collagen deposition, alpha-smooth muscle actin (alpha-SMA) expression, matrix metalloproteinase (MMP)1 activity, tissue inhibitor of MMP (TIMP)1 production, apoptosis and cell proliferation were assessed. Pro-inflammatory cytokines relevant to pulmonary fibrosis were assayed in SAHA-treated human peripheral blood mononuclear cells (PBMC) and its subpopulations. SAHA abrogated TGF-beta 1 effects on all the fibroblast lines by preventing their transdifferentiation into alpha-SMA positive myofibroblasts and increased collagen deposition without inducing apoptosis. However, MMP1 activity and TIMP1 production was modulated without a clear fibrolytic effect. SAHA also inhibited serum-induced proliferation of the fibroblast lines and caused hyperacetylation of alpha-tubulin and histone. Cytokine secretion was inhibited from PBMC and lymphocytes at nonapoptotic concentrations. Taken together, these data demonstrate combined antifibrotic and anti-inflammatory properties of SAHA, suggesting its therapeutic potential for pulmonary fibrosis.

Novel insight into the inflammatory and cellular responses following experimental glaucoma surgery: a roadmap for inhibiting fibrosis.

Failure after glaucoma filtration surgery is attributed to fibrosis at the operated site. To understand the wound healing process after glaucoma filtration surgery, we have developed a mouse model for glaucoma filtration surgery which closely mimics the clinical response. In this study, we describe a systematic analysis of the wound healing response in vivo. Our data revealed that the post-surgical tissue response was separable into two distinguishable phases. The early "acute inflammatory" phase was characterized by significantly increased transcript expression of Vegfa, Cxcl1, Cxcl5, Ccl2, Ccl3, Ccl4, Gmcsf and specific Mmps as well as greater infiltration of monocytes/macrophages and T cells. The late "fibrotic" phase was characterized by an increased expression of Tgfb2 and extracellular matrix genes as well as a notable reduction of infiltrating inflammatory cells. Significantly, more mitotic cells were observed at both time points post-surgery. Subconjunctival fibroblasts may be involved in both phases since they have the capacity to reiterate the in vivo gene expression profiles upon either pro-inflammatory or pro-fibrotic cytokine stimulation. Given that the cellular and molecular targets that govern the early and late phases of wound healing are distinct and time sensitive, a multi-targeted therapeutic approach to sequentially inhibit inflammation and fibrogenesis at the critical time point may lead to improved surgical outcomes in glaucoma filtration surgery.