Browsing by Subject "Histone Deacetylase Inhibitors / pharmacology"
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Item Chromobacterium spp. mediate their anti-Plasmodium activity through secretion of the histone deacetylase inhibitor romidepsin(Springer Nature, 2018-04-18) Saraiva, Raul G.; Huitt-Roehl, Callie R.; Tripathi, Abhai; Cheng, Yi-Qiang; Bosch, Jurgen; Townsend, Craig A.; Dimopoulos, GeorgeThe Chromobacterium sp. Panama bacterium has in vivo and in vitro anti-Plasmodium properties. To assess the nature of the Chromobacterium-produced anti-Plasmodium factors, chemical partition was conducted by bioassay-guided fractionation where different fractions were assayed for activity against asexual stages of P. falciparum. The isolated compounds were further partitioned by reversed-phase FPLC followed by size-exclusion chromatography; high resolution UPLC and ESI/MS data were then collected and revealed that the most active fraction contained a cyclic depsipeptide, which was identified as romidepsin. A pure sample of this FDA-approved HDAC inhibitor allowed us to independently verify this finding, and establish that romidepsin also has potent effect against mosquito stages of the parasite's life cycle. Genomic comparisons between C. sp. Panama and multiple species within the Chromobacterium genus further demonstrated a correlation between presence of the gene cluster responsible for romidepsin production and effective antiplasmodial activity. A romidepsin-null Chromobacterium spp. mutant loses its anti-Plasmodium properties by losing the ability to inhibit P. falciparum HDAC activity, and romidepsin is active against resistant parasites to commonly deployed antimalarials. This independent mode of action substantiates exploring a chromobacteria-based approach for malaria transmission-blocking.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.