Title: Angiotensin II Type 1 Receptor Antibodies and Increased Angiotensin II Sensitivity in Pregnant Rats
Authors: Wenzel, Katrin ×
Rajakumar, Augustine
Haase, Hannelore
Geusens, Nele
Hubner, Norbert
Schulz, Herbert
Brewer, Justin
Roberts, Lyndsay
Hubel, Carl A
Herse, Florian
Hering, Lydia
Qadri, Fatimunnisa
Lindschau, Carsten
Wallukat, Gerd
Pijnenborg, Robert
Heidecke, Harald
Riemekasten, Gabriela
Luft, Friedrich C
Muller, Dominik N
Lamarca, Babette
Dechend, Ralf #
Issue Date: Jul-2011
Publisher: Lippincott Williams & Wilkins
Series Title: Hypertension vol:58 issue:1 pages:77-84
Abstract: Pregnant women who subsequently develop preeclampsia are highly sensitive to infused angiotensin (Ang) II; the sensitivity persists postpartum. Activating autoantibodies against the Ang II type 1 (AT(1)) receptor are present in preeclampsia. In vitro and in vivo data suggest that they could be involved in the disease process. We generated and purified activating antibodies against the AT(1) receptor (AT(1)-AB) by immunizing rabbits against the AFHYESQ epitope of the second extracellular loop, which is the binding epitope of endogenous activating autoantibodies against AT(1) from patients with preeclampsia. We then purified AT(1)-AB using affinity chromatography with the AFHYESQ peptide. We were able to detect AT(1)-AB both by ELISA and a functional bioassay. We then passively transferred AT(1)-AB into pregnant rats, alone or combined with Ang II. AT(1)-AB activated protein kinase C-α and extracellular-related kinase 1/2. Passive transfer of AT(1)-AB alone or Ang II (435 ng/kg per minute) infused alone did not induce a preeclampsia-like syndrome in pregnant rats. However, the combination (AT(1)-AB plus Ang II) induced hypertension, proteinuria, intrauterine growth retardation, and arteriolosclerosis in the uteroplacental unit. We next performed gene-array profiling of the uteroplacental unit and found that hypoxia-inducible factor 1α was upregulated by Ang II plus AT(1)-AB, which we then confirmed by Western blotting in villous explants. Furthermore, endothelin 1 was upregulated in endothelial cells by Ang II plus AT(1)-AB. We show that AT(1)-AB induces Ang II sensitivity. Our mechanistic study supports the existence of an "autoimmune-activating receptor" that could contribute to Ang II sensitivity and possible to preeclampsia.
ISSN: 0194-911X
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Pathophysiology of Pregnancy Section (-)
Section Woman - Miscellaneous (-)
× corresponding author
# (joint) last author

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