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Hydrogen peroxide induces dimerization of protein kinase G type Iα subunits and increases albumin permeability in cultured rat podocytes
Author(s) -
Piwkowska Agnieszka,
Rogacka Dorota,
Jankowski Maciej,
Kocbuch Katarzyna,
Angielski Stefan
Publication year - 2012
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.22810
Subject(s) - hydrogen peroxide , protein kinase a , albumin , chemistry , permeability (electromagnetism) , protein subunit , microbiology and biotechnology , biochemistry , kinase , biology , gene , membrane
Podocytes help regulate filtration barrier permeability in the kidneys. They express contractile proteins that are characteristic of smooth muscle cells as well as receptors for vasoactive factors such as angiotensin II and atrial natriuretic peptide (ANP). The later one generates intracellular cGMP, with subsequent activation of cGMP‐dependent protein kinase; PKG (isoform PKGIα and PKGIβ). In this study, we asked whether hydrogen peroxide (H 2 O 2 ), a physiological vasorelaxing factor, affected podocyte permeability and the podoctye PKGIα signaling pathway. Expression of PKGIα was confirmed in cultured rat podocytes using RT‐PCR, immunofluorescence, and Western blotting. Exposure of podocytes to exogenous H 2 O 2 (100 µM) in non‐reducing conditions increased the formation of PKGIα interprotein disulfide bonds, affected the phosphorylation of PKG target proteins, namely MYPT1 (maximal increase of about 57% at 30 min) and MLC (maximal decrease of about 62% at 10 min). Furthermore, H 2 O 2 increased the permeability of a layer of podocytes to albumin: Transmembrane flux for albumin increased five‐fold (106.6 ± 5.2 µg/ml vs. 20.2 ± 2.5 µg/ml, P < 0.05, n = 5), and the PKG inhibitor Rp‐8‐Br‐cGMPS (100 µM) prevented the flux increase. These data suggest that oxidative modulation of PKGIα in podocytes plays an important role in the regulation of filtration barrier permeability. J. Cell. Physiol. 227: 1004–1016, 2012. © 2011 Wiley Periodicals, Inc.