Methylation in pericytes after acute injury promotes chronic kidney disease
Yu-Hsiang Chou, Szu-Yu Pan, Yu-Han Shao, Hong-Mou Shih, Shi-Yao Wei, Chun-Fu Lai, Wen-Chih Chiang, Claudia Schrimpf, Kai-Chien Yang, Liang-Chuan Lai, Yung-Ming Chen, Tzong-Shinn Chu, Shuei-Liong Lin
Yu-Hsiang Chou, Szu-Yu Pan, Yu-Han Shao, Hong-Mou Shih, Shi-Yao Wei, Chun-Fu Lai, Wen-Chih Chiang, Claudia Schrimpf, Kai-Chien Yang, Liang-Chuan Lai, Yung-Ming Chen, Tzong-Shinn Chu, Shuei-Liong Lin
View: Text | PDF
Research Article Nephrology

Methylation in pericytes after acute injury promotes chronic kidney disease

Abstract

The origin and fate of renal myofibroblasts is not clear after acute kidney injury (AKI). Here, we demonstrate that myofibroblasts were activated from quiescent pericytes (qPericytes) and the cell numbers increased after ischemia/reperfusion injury–induced AKI (IRI-AKI). Myofibroblasts underwent apoptosis during renal recovery but one-fifth of them survived in the recovered kidneys on day 28 after IRI-AKI and their cell numbers increased again after day 56. Microarray data showed the distinctive gene expression patterns of qPericytes, activated pericytes (aPericytes, myofibroblasts), and inactivated pericytes (iPericytes) isolated from kidneys before, on day 7, and on day 28 after IRI-AKI. Hypermethylation of the Acta2 repressor Ybx2 during IRI-AKI resulted in epigenetic modification of iPericytes to promote the transition to chronic kidney disease (CKD) and aggravated fibrogenesis induced by a second AKI induced by adenine. Mechanistically, transforming growth factor-β1 decreased the binding of YBX2 to the promoter of Acta2 and induced Ybx2 hypermethylation, thereby increasing α-smooth muscle actin expression in aPericytes. Demethylation by 5-azacytidine recovered the microvascular stabilizing function of aPericytes, reversed the profibrotic property of iPericytes, prevented AKI-CKD transition, and attenuated fibrogenesis induced by a second adenine-AKI. In conclusion, intervention to erase hypermethylation of pericytes after AKI provides a strategy to stop the transition to CKD.

Authors

Yu-Hsiang Chou, Szu-Yu Pan, Yu-Han Shao, Hong-Mou Shih, Shi-Yao Wei, Chun-Fu Lai, Wen-Chih Chiang, Claudia Schrimpf, Kai-Chien Yang, Liang-Chuan Lai, Yung-Ming Chen, Tzong-Shinn Chu, Shuei-Liong Lin

×

Figure 7

Demethylation by 5-azacytidine reversed the vascular stabilizing function of myofibroblasts.

Options: View larger image (or click on image) Download as PowerPoint
Demethylation by 5-azacytidine reversed the vascular stabilizing functio...
(A) The scheme showing the model of 3D capillary formation by mixing pericytes (green) and HUVECs (red) in collagen gels. (B) A representative bright-field image demonstrating the cross sections of capillary tubes 24 hours after mixing pericytes and HUVECs in collagen gels. Scale bars: 250 μm. Original magnification, ×4. (C) A representative immunofluorescent image showing capillary formation (red) 24 hours after mixing the pericytes and CellTracker Red–stained HUVECs in collagen gels. Scale bars: 250 μm. Original magnification, ×4. (D) Dot chart showing the vascular density in the collagen gels in the presence of coculture with qPericytes (qPC), aPericytes (aPC, myofibroblasts), aPericytes after Aza treatment for 3 days (aPC + Aza), or in the absence of pericyte coculture (HUVEC alone) for 24 hours. n = 10. (E) Images showing the collapse of collagen gels induced by kallikrein (KLK) in gels with HUVECs in the presence or absence of pericyte coculture. Scale bars: 250 μm. Original magnification, ×4. (F) Line chart showing the percentage of collapsed area in gels with HUVECs in the presence or absence of pericyte coculture at the indicated time points after KLK administration. n = 10. (G) Dot charts showing the expression of Timp3, Angpt1, and Angpt2 assessed by quantitative PCR. The expression levels were normalized to Gapdh. Horizontal bars represent the mean, error bars represent the SEM. n = 4. *P < 0.05, **P < 0.01, ***P < 0.001 by 1-way ANOVA with post hoc Tukey’s correction.