Upregulation of angiotensin-(1-7) formation in human podocytes - enzyme activity assay upon fluid flow shear stress

Sep 30, 2026

Uploaded by dawugda

The renin-angiotensin system regulates renal hemodynamics and natriuresis, while excessive activation drives kidney pathology largely through angiotensin II. Counter-regulation involves angiotensin-(1–7), whose generation from angiotensin II depends on prolylcarboxypeptidase, angiotensin converting enzyme 2, and prolyl endopeptidase in a cell- and species-specific manner. The study examines how human podocytes convert angiotensin II to angiotensin-(1–7) after exposure to fluid flow shear stress, using mass spectrometry and selective enzyme inhibitors. Increased angiotensin-(1–7) formation under shear stress relies mainly on prolylcarboxypeptidase activity, clarifying intraglomerular angiotensin II processing relevant to hyperfiltration-associated injury.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages18

Reading Time45 min

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Abstract

Introduction

OPEN ACCESS Citation: Kaiser-Graf D, Domenig O, Poglitsch M, Kreutz R, Bolbrinker J (2026) Upregulation of angiotensin-(1–7) formation in human podocytes – enzyme activity assay upon fluid flow shear stress. PLoS One 21(1): e0339874 . [https://doi.org/10.1371/journal.pone.0339874](https://doi.org/10.1371/journal.pone.0339874) Editor: Junzheng Yang, Guangdong Nephrotic Drug Engineering Technology Research Center, Institute of Consun Co. for Chinese Medicine in Kidney Diseases, CHINA Received: April 14, 2025 Accepted: December 12, 2025 Published: January 9, 2026 Peer Review History: PLOS recognizes the benefits of transparency in the peer review process; therefore, we enable the publication of all of the content of peer review and author responses alongside final, published articles. The editorial history of this article is available here: [https://doi.org/10.1371/journal](https://doi.org/10.1371/journal). pone.0339874 Copyright: © 2026 Kaiser-Graf et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, RESEARCH ARTICLE Upregulation of angiotensin-(1–7) formation inhuman podocytes – enzyme activity assay upon fluid flow shear stress Debora Kaiser-Graf1*, Oliver Domenig2, Marko Poglitsch2, Reinhold Kreutz1, Juliane Bolbrinker1 1 Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and HumboldtUniversität zu Berlin, Institute of Clinical Pharmacology and Toxicology, Berlin, Germany, 2 Attoquant Diagnostics GmbH, Vienna, Austria * debora. kaiser@charite.de Abstract The renin-angiotensin system is known for its role in renal physiology by regulating renal hemodynamics and natriuresis. Overactivation of this system exerts pathological effects in the kidney, primarily mediated by its main effector peptide angiotensin II. Deleterious angiotensin II-mediated effects are counter-regulated at least partly by the biologically active renin-angiotensin system component angiotensin-(1–7) . The processing of angiotensin II to angiotensin-(1–7) by prolylcarboxypeptidase, angiotensin converting enzyme 2, and prolyl endopeptidase is cell-and species-specific, with limited knowledge regarding its conversion in human podocytes under conditions of glomerular hyperfiltration. Since hyperfiltration plays a critical mechanistic role in albuminuria progression and chronic kidney disease, understanding the mechanisms underlying podocyte damage due to glomerular hyperfiltration is essential. Therefore, we investigated the conversion of angiotensin II to angiotensin-(1–7) in cultured human podocytes exposed to fluid flow shear stress and subsequently incubated with spiked angiotensin II. Mass spectrometry of cell lysates and supernatants was performed to evaluate the formation of angiotensin-(1–7) . Contribution of the respective enzymes to angiotensin-(1–7) formation was assessed using selective inhibitors of prolylcarboxypeptidase, angiotensin converting enzyme 2, and prolyl endopeptidase. We detected increased angiotensin-(1–7) formation upon fluid flow shear stress in podocyte lysates, which was mainly dependent on prolylcarboxypeptidase activity. Our study contributes to a deeper understanding of the intraglomerular processing of angiotensin II towards the alternative renin-angiotensin system and its modulation upon fluid flow shear stress. PLOS One | [https://doi.org/10.1371/journal.pone.0339874](https://doi.org/10.1371/journal.pone.0339874) January 9, 2026 1 / 18 which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data availability statement: All relevant data are within the manuscript and its Supporting Information files. Funding: The author(s) received no specific funding for this work. Competing interests: Oliver Domenig and Marko Poglitsch had a paid employment at Attoquant Diagnostics GmbH within the last 5 years. This commercial affiliation

FAQs

What biological pathway does the study focus on?

The study focuses on the renin-angiotensin system and the conversion of angiotensin II to the alternative peptide angiotensin-(1–7) in human podocytes.

How did the researchers test angiotensin-(1–7) formation?

They exposed cultured human podocytes to fluid flow shear stress, incubated cells with spiked angiotensin II, and then used mass spectrometry to quantify angiotensin-(1–7) in cell lysates and supernatants.

Which enzyme activity primarily drives the increased angiotensin-(1–7) formation?

The increased angiotensin-(1–7) formation upon fluid flow shear stress was mainly dependent on prolylcarboxypeptidase activity, assessed using selective enzyme inhibitors.

Sep 30, 2026

Uploaded by dawugda