Post-Transcriptional Regulation of Endothelial Nitric Oxide Synthase Expression by Polypyrimidine Tract-Binding Protein 1.
Arterioscler Thromb Vasc Biol
; 35(10): 2153-60, 2015 Oct.
Article
em En
| MEDLINE
| ID: mdl-26293469
ABSTRACT
OBJECTIVE:
Endothelial nitric oxide synthase (eNOS) is an important regulator of vascular function and its expression is regulated at post-transcriptional levels through a yet unknown mechanism. The purpose of this study is to elucidate the post-transcriptional factors regulating eNOS expression and function in endothelium. APPROACHES ANDRESULTS:
To elucidate the molecular basis of tumor necrosis factor (TNF)-α-mediated eNOS mRNA instability, biotinylated eNOS 3'-untranslational region (UTR) was used to purify its associated proteins by RNA affinity chromatography from cytosolic fractions of TNF-α-stimulated human umbilical vein endothelial cells (HUVECs). We identified 2 cytosolic proteins, with molecular weight of 52 and 57 kDa, which specifically bind to eNOS 3'-UTR in response to TNF-α stimulation. Matrix-assisted laser desorption ionization time-of-flight mass spectrometric analysis identified the 57-kDa protein as polypyrimidine tract-binding protein 1 (PTB1). RNA gel mobility shift and UV cross-linking assays demonstrated that PTB1 binds to a UCUU-rich sequence in eNOS 3'-UTR, and the C-terminal half of PTB1 is critical to this interaction. Importantly, PTB1 overexpression leads to decreased activity of luciferase gene fused with eNOS 3'-UTR as well as reduced eNOS expression and activity in human ECs. In HUVECs, we show that TNF-α markedly increased PTB1 expression, whereas adenovirus-mediated PTB1 overexpression decreased eNOS mRNA stability and reduced protein expression and endothelium-dependent relaxation. Furthermore, knockdown of PTB1 substantially attenuated TNF-α-induced destabilization of eNOS transcript and downregulation of eNOS expression.CONCLUSIONS:
These results indicate that PTB1 is essential for regulating eNOS expression at post-transcriptional levels and suggest a novel therapeutic target for treatment of vascular diseases associated with inflammatory endothelial dysfunction.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Regulação da Expressão Gênica
/
Fator de Necrose Tumoral alfa
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Proteína de Ligação a Regiões Ricas em Polipirimidinas
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Óxido Nítrico Sintase Tipo III
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Limite:
Humans
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article