trichostatin-a and Nasal-Polyps

Nasal polyposis is associated with a chronic inflammatory condition of the sinonasal mucosa and involves myofibroblast differentiation and extracellular matrix (ECM) accumulation. Epigenetic modulation by histone deacetylase (HDAC) inhibitors including trichostatin A (TSA) has been reported to have inhibitory effects on myofibroblast differentiation in lung and renal fibroblasts. The purpose of this study was to investigate the inhibitory effect of TSA on myofibroblast differentiation and ECM production in nasal polyp organ cultures.. Nasal polyp tissues from 18 patients were acquired during endoscopic sinus surgery. After organ culture, nasal polyps were stimulated with TGF-beta1 and then treated with TSA. Alpha-smooth muscle actin (α-SMA), fibronectin, and collagen type I expression levels were examined by reverse transcription-polymerase chain reaction (PCR), real-time PCR, Western blot, and immunofluorescent staining. HDAC2, HDAC4, and acetylated H4 expression levels were assayed by Western blot. Cytotoxicity was analyzed by the terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling assay.. The expression levels of α-SMA, fibronectin, and collagen type 1 were increased in nasal polyp after transforming growth factor (TGF) beta1 treatment. TSA-inhibited TGF-beta1 induced these gene and protein expression levels. Furthermore, TSA suppressed protein expression levels of HDAC2 and HDAC4. However, TSA induced hyperacetylation of histones H4. Treatment with TGF-beta1 with or without TSA did not have cytotoxic effect.. These findings provide novel insights into the epigenetic regulation in myofibroblast differentiation and ECM production of nasal polyp. TSA could be a candidate of a therapeutic agent for reversing the TGF-beta1-induced ECM synthesis that leads to nasal polyp development.

Topics: Acetylation; Actins; Apoptosis; Cell Differentiation; Cells, Cultured; Collagen Type I; Extracellular Matrix; Fibronectins; Gene Expression Regulation; Histone Deacetylase 2; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Hydroxamic Acids; Myofibroblasts; Nasal Polyps; Organ Culture Techniques; Repressor Proteins; Transforming Growth Factor beta1

Nasal polyposis is a multi-factorial disease associated with chronic inflammatory condition of the paranasal sinuses. Myofibroblast differentiation and extracellular matrix (ECM) accumulation are involved in the pathogenesis of nasal polyposis.. The aim of this study was to study the effect of trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor, on transforming growth factor (TGF)-β1-induced myofibroblast differentiation and ECM accumulation in nasal polyp-derived fibroblasts (NPDFs).. Nasal polyp-derived fibroblasts were isolated from nasal polyps of patients who have chronic rhinosinusitis with nasal polyp. TSA was treated in TGF-β1-induced NPDFs. Expression levels of HDAC2, α-smooth muscle actin (SMA), TGF-β1, collagen type I, acetylated Histone H3, acetylated Histone H4, phosphorylated Smad2/3 and Smad7 were determined by RT-PCR, western blot and/or immunofluorescent staining. The total collagen amount production was analysed by Sircol soluble collagen assay and contractile activity was measured by collagen gel contraction assay. HDAC2 inhibition by TSA or HDAC2 silencing was established by RT-PCR and western blot. The epigenetic effect on α-SMA gene inactivation was examined by chromatin immunoprecipitation assay. Proliferation was determined by Ki67-positive cell staining and cytotoxicity was assessed by 3-(4,5- dimethylthiazol-2yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay.. The expression levels of HDAC2, α-SMA and TGF-β1 were increased in nasal polyp tissues compared to normal inferior turbinate tissues. TSA and HDAC2 silencing inhibited expression levels α-SMA, collagen and HDAC2. TSA induced hyperacetylation of histone and suppressed opening of α-SMA gene promoter in TGF-β1-induced NPDFs. TSA inhibited TGF-β1-induced Smad 2/3 and rescued TGF-β1-suppressed Smad7 signalling pathway. Finally, TSA blocked proliferation in TGF-β1-induced NPDFs and has no cytotoxic effect in NPDFs.. These results suggest that HDAC inhibition is associated with myofibroblast differentiation and extracelluar matrix accumulation in nasal polyposis. TSA may be useful as an inhibitor of nasal polyp growth, and thus has potential to be used as a novel treatment option for nasal polyposis.

Topics: Acetylation; Actins; Cell Differentiation; Cell Proliferation; Cells, Cultured; Epigenesis, Genetic; Extracellular Matrix; Fibroblasts; Gene Expression Regulation; Histone Deacetylase 2; Histone Deacetylase Inhibitors; Histones; Humans; Hydroxamic Acids; Myofibroblasts; Nasal Polyps; Phosphorylation; Smad2 Protein; Smad3 Protein; Transforming Growth Factor beta1