KLF4-dependent epigenetic remodeling modulates podocyte phenotypes and attenuates proteinuria
Kaori Hayashi, … , Yusuke Sakamaki, Hiroshi Itoh
Kaori Hayashi, … , Yusuke Sakamaki, Hiroshi Itoh
Published May 8, 2014
Citation Information: J Clin Invest. 2014;124(6):2523-2537. https://doi.org/10.1172/JCI69557.
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Research Article Nephrology

KLF4-dependent epigenetic remodeling modulates podocyte phenotypes and attenuates proteinuria

Abstract

The transcription factor Kruppel-like factor 4 (KLF4) has the ability, along with other factors, to reprogram somatic cells into induced pluripotent stem (iPS) cells. Here, we determined that KLF4 is expressed in kidney glomerular podocytes and is decreased in both animal models and humans exhibiting a proteinuric. Transient restoration of KLF4 expression in podocytes of diseased glomeruli in vivo, either by gene transfer or transgenic expression, resulted in a sustained increase in nephrin expression and a decrease in albuminuria. In mice harboring podocyte-specific deletion of Klf4, adriamycin-induced proteinuria was substantially exacerbated, although these animals displayed minimal phenotypical changes prior to adriamycin administration. KLF4 overexpression in cultured human podocytes increased expression of nephrin and other epithelial markers and reduced mesenchymal gene expression. DNA methylation profiling and bisulfite genomic sequencing revealed that KLF4 expression reduced methylation at the nephrin promoter and the promoters of other epithelial markers; however, methylation was increased at the promoters of genes encoding mesenchymal markers, suggesting selective epigenetic regulation of podocyte gene expression. Together, these results suggest that KLF4 epigenetically modulates podocyte phenotype and function and that the podocyte epigenome can be targeted for direct intervention and reduction of proteinuria.

Authors

Kaori Hayashi, Hiroyuki Sasamura, Mari Nakamura, Tatsuhiko Azegami, Hideyo Oguchi, Yusuke Sakamaki, Hiroshi Itoh

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Figure 5

KLF4 expression causes morphological changes and induces epithelial cell markers in cultured podocytes.

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KLF4 expression causes morphological changes and induces epithelial cell...
(A) Western blot analysis of KLF4 expression in undifferentiated podocytes cultured at 33°C or differentiated podocytes cultured at 37°C. (B) Representative photomicrographs of (upper/middle panel) cell morphology at high/low confluence and (lower panel) immunofluorescence labeling with F-actin in KLF4-overexpressing podocytes and empty vector–transfected controls. Scale bars: 100 μm (upper panel); 50 μm (middle panel); 10 μm (lower panel). (C) Representative Western blots and (D) quantification of epithelial or mesenchymal markers expression in KLF4-overexpressing podocytes and controls (n = 4). (E) Real-time RT-PCR analysis of mRNA expression in KLF4-overexpressing podocytes and controls (n = 6). (F and G) In vitro permeability of FITC-labeled albumin through podocyte monolayers in KLF4-overexpressing podocytes and controls without (F) or with (G) ADM (0.3 μg/ml) for 48 hours (n = 6). The passage of albumin was measured at indicated hours after FITC-albumin administration. *P < 0.05; **P < 0.01 vs. controls.