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AT1 receptor agonistic antibodies from preeclamptic patients stimulate NADPH oxidase

Authors

  • R. Dechend
  • C. Viedt
  • D.N. Mueller
  • B. Ugele
  • R.P. Brandes
  • G. Wallukat
  • J.K. Park
  • J. Janke
  • P. Barta
  • J. Theuer
  • A. Fiebeler
  • V. Homuth
  • R. Dietz
  • H. Haller
  • J. Kreuzer
  • F.C. Luft

Journal

  • Circulation

Citation

  • Circulation 107 (12): 1632-1639

Abstract

  • BACKGROUND: We recently identified agonistic autoantibodies directed against the angiotensin AT1 receptor (AT1-AA) in the plasma of preeclamptic women. To elucidate their role further, we studied the effects of AT1-AA on reactive oxygen species (ROS), NADPH oxidase expression, and nuclear factor-kappaB (NF-kappaB) activation. METHODS AND RESULTS: We investigated human vascular smooth muscle cells (VSMC) and trophoblasts, as well as placentas. AT1-AA were isolated from sera of preeclamptic women. Angiotensin II (Ang II) and AT1-AA increased ROS production and the NADPH oxidase components, p22, p47, and p67 phox in Western blotting. We next tested if AT1-AA lead to NF-kappaB activation in VSMC and trophoblasts. AT1-AA activated NF-kappaB. Inhibitor-kappaBalpha (I-kappaBalpha) expression was reduced in response to AT1-AA. AT1 receptor blockade with losartan, diphenylene iodonium, tiron, and antisense against p22 phox all reduced ROS production and NF-kappaB activation. VSMC from p47phox-/- mice showed markedly reduced ROS generation and NF-kappaB activation in response to Ang II and AT1-AA. The p22, p47, and p67 phox expression in placentas from preeclamptic patients was increased, compared with normal placentas. Furthermore, NF-kappaB was activated and I-kappaBalpha reduced in placentas from preeclamptic women. CONCLUSIONS: NADPH oxidase is potentially an important source of ROS that may upregulate NF-kappaB in preeclampsia. We suggest that AT1-AA through activation of NADPH oxidase could contribute to ROS production and inflammatory responses in preeclampsia.


DOI

doi:10.1161/01.CIR.0000058200.90059.B1