Attribution 4.0 International (CC BY 4.0)2022-08-252022-08-252016-07-01Bermudez, J. Y., Webber, H. C., Patel, G. C., Liu, X., Cheng, Y. Q., Clark, A. F., & Mao, W. (2016). HDAC Inhibitor-Mediated Epigenetic Regulation of Glaucoma-Associated TGFβ2 in the Trabecular Meshwork. Investigative ophthalmology & visual science, 57(8), 3698-3707. https://doi.org/10.1167/iovs16-194461552-5783https://hdl.handle.net/20.500.12503/31658PURPOSE: Elevated intraocular pressure (IOP) in primary open-angle glaucoma (POAG) results from glaucomatous damage to the trabecular meshwork (TM). The glaucoma-associated factor TGFbeta2 is increased in aqueous humor and TM of POAG patients. We hypothesize that histone acetylation has a role in dysregulated TGFbeta2 expression. METHODS: Protein acetylation was compared between nonglaucomatous TM (NTM) and glaucomatous TM (GTM) cells using Western immunoblotting (WB). Nonglaucomatous TM cells were treated with 10 nM thailandepsin-A (TDP-A), a potent histone deacetylase inhibitor for 4 days. Total and nuclear proteins, RNA, and nuclear protein-DNA complexes were harvested for WB, quantitative PCR (qPCR), and chromatin immunoprecipitation (ChIP) assays, respectively. Paired bovine eyes were perfused with TDP-A versus DMSO, or TDP-A versus TDP-A plus the TGFbeta pathway inhibitor LY364947 for 5 to 9 days. Intraocular pressure, TM, and perfusate proteins were compared. RESULTS: We found increased acetylated histone 3 and total protein acetylation in the GTM cells and TDP-A treated NTM cells. Chromatin immunoprecipitation assays showed that TDP-A induced histone hyperacetylation associated with the TGFbeta2 promoter. This change of acetylation significantly increased TGFbeta2 mRNA and protein expression in NTM cells. In perfusion-cultured bovine eyes, TDP-A increased TGFbeta2 in the perfusate as well as elevated IOP. Histologic and immunofluorescent analyses showed increased extracellular matrix and cytoskeletal proteins in the TM of TDP-A treated bovine eyes. Cotreatment with the TGFbeta pathway inhibitor LY364947 blocked TDP-A-induced ocular hypertension. CONCLUSIONS: Our results suggest that histone acetylation has an important role in increased expression of the glaucoma-associated factor TGFbeta2. Histone hyperacetylation may be the initiator of glaucomatous damage to the TM.http://creativecommons.org/licenses/by/4.0/AcetylationAnimalsCattleCells, CulturedEpigenesis, Genetic / geneticsGlaucoma, Open-Angle / geneticsHistone Deacetylase Inhibitors / pharmacologyPyrazoles / pharmacologyPyrroles / pharmacologyRNA, Messenger / metabolismTrabecular Meshwork / physiologyTransforming Growth Factor beta2 / geneticsArticleCopyright 2016 the Authors578