Browsing by Subject "RNA, Messenger / metabolism"
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Item HDAC Inhibitor-Mediated Epigenetic Regulation of Glaucoma-Associated TGFbeta2 in the Trabecular Meshwork(ARVO Journals, 2016-07-01) Bermudez, Jaclyn Y.; Webber, Hannah C.; Patel, Gaurang C.; Liu, Xiangyang; Cheng, Yi-Qiang; Clark, Abbot F.; Mao, WeimingPURPOSE: 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.Item Presence of Androgen Receptor Variant in Neuronal Lipid Rafts(Society for Neuroscience, 2017-08-29) Garza-Contreras, Jo; Duong, Phong; Snyder, Brina D.; Schreihofer, Derek A.; Cunningham, Rebecca L.Fast, nongenomic androgen actions have been described in various cell types, including neurons. However, the receptor mediating this cell membrane-initiated rapid signaling remains unknown. This study found a putative androgen receptor splice variant in a dopaminergic N27 cell line and in several brain regions (substantia nigra pars compacta, entorhinal cortex, and hippocampus) from gonadally intact and gonadectomized (young and middle-aged) male rats. This putative splice variant protein has a molecular weight of 45 kDa and lacks an N-terminal domain, indicating it is homologous to the human AR45 splice variant. Interestingly, AR45 was highly expressed in all brain regions examined. In dopaminergic neurons, AR45 is localized to plasma membrane lipid rafts, a microdomain involved in cellular signaling. Further, AR45 protein interacts with membrane-associated G proteins Galphaq and Galphao. Neither age nor hormone levels altered AR45 expression in dopaminergic neurons. These results provide the first evidence of AR45 protein expression in the brain, specifically plasma membrane lipid rafts. AR45 presence in lipid rafts indicates that it may function as a membrane androgen receptor to mediate fast, nongenomic androgen actions.