Hypoxia-Inducible Factor-1α Mediates Increased Sympathoexcitation via Glutamatergic N-Methyl-d-Aspartate Receptors in the Paraventricular Nucleus of Rats with Chronic Heart Failure

Neeru M. Sharma, Craig J. Cunningham, Hong Zheng, Xuefei Liu, Kaushik P. Patel

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

Background-Increased sympathetic outflow is a major contributor to the progression of chronic heart failure (CHF). Potentiation of glutamatergic tone has been causally related to the sympathoexcitation in CHF. Specifically, an increase in the N-methyl-d-aspartate-type 1 receptor (NMDA-NR1) expression within the paraventricular nucleus (PVN) is critically linked to the increased sympathoexcitation during CHF. However, the molecular mechanism(s) for the upregulation of NMDA-NR1 remains unexplored. We hypothesized that hypoxia via hypoxia-inducible factor 1α (HIF-1α) might contribute to the augmentation of the NMDA-NR1-mediated sympathoexcitatory responses from the PVN in CHF. Methods and Results-Immunohistochemistry staining, mRNA, and protein for hypoxia-inducible factor 1α were upregulated within the PVN of left coronary artery-ligated CHF rats. In neuronal cell line (NG108-15) in vitro, hypoxia caused a significant increase in mRNA and protein for HIF-1α (2-fold) with the concomitant increase in NMDA-NR1 mRNA, protein levels, and glutamate-induced Ca+ influx. Chromatin immunoprecipitation assay identified HIF-1α binding to NMDA-NR1 promoter during hypoxia. Silencing of HIF-1α in NG108 cells leads to a significant decrease in expression of NMDA-NR1, suggesting that expression of HIF-1α is necessary for the upregulation of NMDA-NR1. Consistent with these observations, HIF-1α silencing within the PVN abrogated the increased basal sympathetic tone and sympathoexcitatory responses to microinjection of NMDA in the PVN of rats with CHF. Conclusions-These results uncover a critical role for HIF-1 in the upregulation of NMDA-NR1 to mediate sympathoexcitation in CHF. We conclude that subtle hypoxia within the PVN may act as a metabolic cue to modulate sympathoexcitation during CHF.

Original languageEnglish (US)
Article numbere003423
JournalCirculation: Heart Failure
Volume9
Issue number11
DOIs
StatePublished - Nov 1 2016

Keywords

  • Hypoxia-Inducible factor 1
  • NMDA receptors
  • myocardial ischemia
  • paraventricular nucleus

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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