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Regulation of VEGF mRNA expression in hypoxic pulmonary artery endothelial cells (PAECs) by histone deacetylases (HDACs)
Author(s) -
Middleton Natavia S.,
Ruchko Mykhaylo,
Gorodnya Olena,
Gillespie Mark N.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1155.18
Subject(s) - trichostatin a , chromatin , chromatin remodeling , chromatin immunoprecipitation , microbiology and biotechnology , histone , transcription factor , biology , regulation of gene expression , gene expression , histone deacetylase , chemistry , promoter , gene , biochemistry
The mechanism by which HDACs regulate gene expression in hypoxia is not understood. Some evidence suggests that HDACs act directly on HIF‐1, a key transcription factor, to facilitate binding to the hypoxic response element (HRE). Other studies indicate that HDACs impact chromatin‐remodeling processes and modulate access of the HRE to transcriptional proteins. To explore these possibilities, we first used Western immunoblot and DNA affinity precipitation analyses to determine if the HDAC inhibitor, trichostatin A (TSA), altered abundances and DNA binding activities, respectively, of HIF‐1, p300, and HDAC1 in normoxic and hypoxic PAEC nuclear extracts. While HDAC inhibition caused minor changes in nuclear abundances of these transcriptional proteins, their association with a 65‐mer oligonucleotide sequence of the VEGF HRE was unaffected. Next, using chromatin immunoprecipitation assays to examine transcriptional complex formation in intact PAECs, we found that TSA suppressed HIF‐1, p300, and HDAC1 binding to the HRE of the VEGF gene. Nuclease digestion assays showed that TSA redistributed the VEGF HRE from transcriptionally active mononucleosomes to highly condensed chromatin structures. These findings suggest HDACs are recruited to the VEGF HRE in PAECs where they regulate hypoxia‐induced VEGF expression by remodeling chromatin and facilitating transcriptional complex formation. Supported by NIH and AHA