Hydrogen peroxide induces dimerization of protein kinase G type I alpha subunits and increases albumin permeability in cultured rat podocytes

作者：Piwkowska Agnieszka^*; Rogacka Dorota; Jankowski Maciej; Kocbuch Katarzyna; Angielski Stefan

来源：Journal of Cellular Physiology, 2012, 227(3): 1004-1016.

DOI：10.1002/jcp.22810

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 PKGIa and PKGI beta). In this study, we asked whether hydrogen peroxide (H2O2), a physiological vasorelaxing factor, affected podocyte permeability and the podoctye PKGIa signaling pathway. Expression of PKGIa was confirmed in cultured rat podocytes using RT-PCR, immunofluorescence, and Western blotting. Exposure of podocytes to exogenous H2O2 (100 mu M) in non-reducing conditions increased the formation of PKGIa interprotein disulfide bonds, affected the phosphorylation of PKG target proteins, namely MYPT1 (maximal increase of about 57% at 30min) and MLC (maximal decrease of about 62% at 10min). Furthermore, H2O2 increased the permeability of a layer of podocytes to albumin: Transmembrane flux for albumin increased five-fold (106.6 +/- 5.2 mu g/ml vs. 20.2 +/- 2.5 mu g/ml, P<0.05, n=5), and the PKG inhibitor Rp-8-Br-cGMPS (100 mu M) prevented the flux increase. These data suggest that oxidative modulation of PKGIa in podocytes plays an important role in the regulation of filtration barrier permeability. J. Cell. Physiol. 227: 10041016, 2012.

• 出版日期2012-3