title: HDAC Inhibitor-Mediated Epigenetic Regulation of Glaucoma-Associated TGFβ2 in the Trabecular Meshwork.
abstract: Elevated intraocular pressure (IOP) in primary open-angle glaucoma (POAG) results from glaucomatous damage to the trabecular meshwork (TM). The glaucoma-associated factor TGFβ2 is increased in aqueous humor and TM of POAG patients. We hypothesize that histone acetylation has a role in dysregulated TGFβ2 expression.
  
  
  
  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 TGFβ pathway inhibitor LY364947 for 5 to 9 days. Intraocular pressure, TM, and perfusate proteins were compared.
  
  
  
  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 TGFβ2 promoter. This change of acetylation significantly increased TGFβ2 mRNA and protein expression in NTM cells. In perfusion-cultured bovine eyes, TDP-A increased TGFβ2 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 TGFβ pathway inhibitor LY364947 blocked TDP-A-induced ocular hypertension.
  
  
  
  Our results suggest that histone acetylation has an important role in increased expression of the glaucoma-associated factor TGFβ2. Histone hyperacetylation may be the initiator of glaucomatous damage to the TM.
authors.affiliation: North Texas Eye Research Institute University of North Texas Health Science Center, Fort Worth, Texas, United States.
authors.forename: Jaclyn Y
authors.initials: JY
authors.lastname: Bermudez
authors.affiliation: North Texas Eye Research Institute University of North Texas Health Science Center, Fort Worth, Texas, United States.
authors.forename: Hannah C
authors.initials: HC
authors.lastname: Webber
authors.affiliation: North Texas Eye Research Institute University of North Texas Health Science Center, Fort Worth, Texas, United States.
authors.forename: Gaurang C
authors.initials: GC
authors.lastname: Patel
authors.affiliation: UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas, United States.
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Liu
authors.affiliation: UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas, United States.
authors.forename: Yi-Qiang
authors.initials: YQ
authors.lastname: Cheng
authors.affiliation: North Texas Eye Research Institute University of North Texas Health Science Center, Fort Worth, Texas, United States.
authors.forename: Abbot F
authors.initials: AF
authors.lastname: Clark
authors.affiliation: North Texas Eye Research Institute University of North Texas Health Science Center, Fort Worth, Texas, United States.
authors.forename: Weiming
authors.initials: W
authors.lastname: Mao
mesh_terms: D000107:Acetylation; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D044127:Epigenesis, Genetic / Q000235:genetics*; D005902:Glaucoma, Open-Angle / Q000235:genetics*; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology*; D011720:Pyrazoles / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D014129:Trabecular Meshwork / Q000502:physiology*; D053781:Transforming Growth Factor beta2 / Q000235:genetics*; D011804:Quinolines
chemical_list: D056572:Histone Deacetylase Inhibitors; D011720:Pyrazoles; D011758:Pyrroles; D012333:RNA, Messenger; D053781:Transforming Growth Factor beta2; C506615:HTS 466284; D011804:Quinolines