Angiotensin II Type I Receptor Agonistic Autoantibody Induces Podocyte Injury via Activation of the TRPC6- Calcium/Calcineurin Pathway in Pre-Eclampsia

• Published in: Kidney & blood pressure research Vol. 43; no. 5; pp. 1666 - 1676
• Main Authors: Yu, Ying, Zhang, Lihong, Xu, Guang, Wu, Zhenghong, Li, Qian, Gu, Yong, Niu, Jianying
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland S. Karger AG 01.01.2018; Karger Publishers
• Subjects: Actin; Activation; Adult; Angiotensin; Angiotensin II; Angiotensin II type I receptor agonistic autoantibody /AT1-AA; Apoptosis; Autoantibodies; Autoantibodies - blood; Autoantibodies - pharmacology; Calcineurin; Calcineurin - metabolism; Calcium; Calcium (intracellular); Calcium - metabolism; Calcium ions; Calcium/calcineurin; Cells, Cultured; Change detection; Chromatography; Endothelin 1; Endothelins; Enzyme-linked immunosorbent assay; Female; Hospitals; Humans; Hypertension; Immunofluorescence; Inhibitors; Intracellular; Kidney diseases; Kinases; Metabolic Networks and Pathways - drug effects; Original Paper; Peptides; Phosphorylation; Podocyte; Podocytes - drug effects; Podocytes - metabolism; Podocytes - pathology; Pre-eclampsia; Pre-Eclampsia - blood; Pre-Eclampsia - metabolism; Preeclampsia; Pregnancy; Proteins; Proteinuria; Receptor, Angiotensin, Type 1 - immunology; Receptor, Angiotensin, Type 1 - therapeutic use; siRNA; TRPC6; TRPC6 Cation Channel - metabolism; Vasoconstriction; United States > US; China; Podocyte; Angiotensin II type I receptor agonistic autoantibody /AT1-AA; TRPC6; Pre-eclampsia; Calcium/calcineurin
• ISSN: 1420-4096; 1423-0143; 1423-0143
• DOI: 10.1159/000494744

Background/Aims: Angiotensin II type I receptor agonistic autoantibody (AT1-AA) is closely related to pre-eclampsia, which is characterized by proteinuria and hypertension. AT1-AA has been shown to enhance the effect of AngII in pre-eclampsia, such as production of endothelin-1, activation of ROS, and vasoconstriction, which are considered to be associated with hypertension; however, whether or not AT1-AA participates in podocyte damage leading to the generation of proteinuria has not been reported. In this study we investigated the role of pre-eclamptic serum AT1-AA on podocytes and the mechanism underlying the generation of proteinuria. Methods: The levels of AT1-AA isolated from pre-eclamptic sera were determined by an enzyme-linked immunosorbent assay. Human podocytes were cultured in vitro and treated with various concentrations of AT1-AA. Whether or not an ERK1/2 inhibitor and TRPC6 siRNA inhibit the effect of AT1-AA on podocytes was determined. Western blot was used to detect the expression of podocyte-specific proteins (nephrin, synaptopodin, and podocin) and the phosphorylation of ERK1/2 and TRPC6. The arrangement of F-actin was observed by immunofluorescence. A Calcineurin Cellular Activity Assay Kit was used to detect calcineurin activity. Changes in the intracellular Ca 2+ concentration was determined by confocal laser. Results: AT1-AA induced a decrease in podocyte-specific protein expression and calcineurin activity and increased expression of p-ERK1/2 and TRPC6 protein and the intracellular Ca 2+ concentration. Immunofluorescence revealed rearrangement of F-actin. PD98059, an inhibitor of ERK1/2, and TRPC6 siRNA attenuated the decreased expression of podocyte-specific proteins and decreased intracellular Ca 2+ concentration. The expression of TRPC6 was reduced following the addition of ERK1/2 inhibitor. Conclusion: AT1-AA induced podocyte damage in a dose-dependent manner. The underlying mechanism might involve activation of the TRPC6 –calcium/calcineurin pathway. This study provides new details regarding podocyte injury and the mechanism underlying the generation of proteinuria in pre-eclampsia.