Nicotinamide adenine dinucleotide phosphate reduced oxidase 5 (Nox5) regulation by angiotensin II and endothelin-1 is mediated via calcium/calmodulin-dependent, Rac-1-independent pathways in human endothelial cells

Augusto C. Montezano, Dylan Burger, Tamara M. Paravicini, Andreia Z. Chignalia, Hiba Yusuf, Mahmoud Almasri, Ying He, Glaucia E. Callera, Gang He, Karl Heinz Krause, David Lambeth, Mark T. Quinn, Rhian M. Touyz

Research output: Contribution to journalArticlepeer-review

130 Scopus citations

Abstract

Rationale: Although Nox5 (Nox2 homolog) has been identified in the vasculature, its regulation and functional significance remain unclear. Objectives: We sought to test whether vasoactive agents regulate Nox5 through Ca2+/ calmodulin-dependent processes and whether Ca 2+-sensitive Nox5, associated with Rac-1, generates superoxide (O2.-) and activates growth and inflammatory responses via mitogen-activated protein kinases in human endothelial cells (ECs). Methods and Results: Cultured ECs, exposed to angiotensin II (Ang II) and endothelin (ET)-1 in the absence and presence of diltiazem (Ca2+ channel blocker), calmidazolium (calmodulin inhibitor), and EHT1864 (Rac-1 inhibitor), were studied. Nox5 was downregulated with small interfering RNA. Ang II and ET-1 increased Nox5 expression (mRNA and protein). Effects were inhibited by actinomycin D and cycloheximide and blunted by diltiazem, calmidazolium and low extracellular Ca2+ ([Ca2+]e). Ang II and ET-1 activated NADPH oxidase, an effect blocked by low [Ca2+]e, but not by EHT1864. Nox5 knockdown abrogated agonist-stimulated O 2.- production and inhibited phosphorylation of extracellular signal-regulated kinase (ERK)1/2, but not p38 MAPK (mitogen-activated protein kinase) or SAPK/JNK (stress-activated protein kinase/c-Jun N-terminal kinase). Nox5 small interfering RNA blunted Ang II-induced, but not ET-1-induced, upregulation of proliferating-cell nuclear antigen and vascular cell adhesion molecule-1, important in growth and inflammation. Conclusions: Human ECs possess functionally active Nox5, regulated by Ang II and ET-1 through Ca2+/calmodulin-dependent, Rac-1-independent mechanisms. Nox5 activation by Ang II and ET-1 induces ROS generation and ERK1/2 phosphorylation. Nox5 is involved in ERK1/2-regulated growth and inflammatory signaling by Ang II but not by ET-1. We elucidate novel mechanisms whereby vasoactive peptides regulate Nox5 in human ECs and demonstrate differential Nox5-mediated functional responses by Ang II and ET-1. Such phenomena link Ca2+/calmodulin to Nox5 signaling, potentially important in the regulation of endothelial function by Ang II and ET-1.

Original languageEnglish (US)
Pages (from-to)1363-1373
Number of pages11
JournalCirculation research
Volume106
Issue number8
DOIs
StatePublished - Apr 30 2010
Externally publishedYes

Keywords

  • ERK1/2
  • Reactive oxygen species
  • Vascular cells
  • Vasoactive peptides

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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