Shifts in podocyte histone H3K27me3 regulate mouse and human glomerular disease
Syamantak Majumder, … , Ferhan S. Siddiqi, Andrew Advani
Syamantak Majumder, … , Ferhan S. Siddiqi, Andrew Advani
Published December 11, 2017
Citation Information: J Clin Invest. 2018;128(1):483-499. https://doi.org/10.1172/JCI95946.
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Research Article Endocrinology Nephrology

Shifts in podocyte histone H3K27me3 regulate mouse and human glomerular disease

Abstract

Histone protein modifications control fate determination during normal development and dedifferentiation during disease. Here, we set out to determine the extent to which dynamic changes to histones affect the differentiated phenotype of ordinarily quiescent adult glomerular podocytes. To do this, we examined the consequences of shifting the balance of the repressive histone H3 lysine 27 trimethylation (H3K27me3) mark in podocytes. Adriamycin nephrotoxicity and subtotal nephrectomy (SNx) studies indicated that deletion of the histone methylating enzyme EZH2 from podocytes decreased H3K27me3 levels and sensitized mice to glomerular disease. H3K27me3 was enriched at the promoter region of the Notch ligand Jag1 in podocytes, and derepression of Jag1 by EZH2 inhibition or knockdown facilitated podocyte dedifferentiation. Conversely, inhibition of the Jumonji C domain–containing demethylases Jmjd3 and UTX increased the H3K27me3 content of podocytes and attenuated glomerular disease in adriamycin nephrotoxicity, SNx, and diabetes. Podocytes in glomeruli from humans with focal segmental glomerulosclerosis or diabetic nephropathy exhibited diminished H3K27me3 and heightened UTX content. Analogous to human disease, inhibition of Jmjd3 and UTX abated nephropathy progression in mice with established glomerular injury and reduced H3K27me3 levels. Together, these findings indicate that ostensibly stable chromatin modifications can be dynamically regulated in quiescent cells and that epigenetic reprogramming can improve outcomes in glomerular disease by repressing the reactivation of developmental pathways.

Authors

Syamantak Majumder, Karina Thieme, Sri N. Batchu, Tamadher A. Alghamdi, Bridgit B. Bowskill, M. Golam Kabir, Youan Liu, Suzanne L. Advani, Kathryn E. White, Laurette Geldenhuys, Karthik K. Tennankore, Penelope Poyah, Ferhan S. Siddiqi, Andrew Advani

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Figure 1

Decreasing H3K27me3 levels in podocytes renders mice susceptible to glomerular injury.

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Decreasing H3K27me3 levels in podocytes renders mice susceptible to glom...
(A) Dual immunofluorescence of normal mouse glomeruli stained for H3K27me3 (n = 3) or EZH2 (n = 3) and the podocyte protein nephrin. DAPI staining is shown in blue. Thick white arrows label H3K27me3 in mouse podocytes, and thin white arrows label EZH2 in mouse podocytes. (B) Dual immunofluorescence for nephrin and EZH2 in glomeruli from EZH2Ctrl (n = 3) and EZH2podKO (n = 3) mice showing diminished podocyte EZH2 in the EZH2podKO glomerulus (arrowheads). (C) Immunoblotting for EZH2 in primary cultured podocytes from EZH2Ctrl (n = 3) and EZH2podKO (n = 3) mice. (D) Immunoblotting for H3K27me3 in primary cultured podocytes from EZH2Ctrl (n = 3) and EZH2podKO (n = 3) mice. (E) PAS-stained kidney sections (original magnification, ×400) and transmission electron micrographs from EZH2Ctrl (n = 3) and EZH2podKO (n = 3) mice under basal conditions. Scale bars: 2 μm. (F) Urine albumin/creatinine ratio 10 days after injection of adriamycin into EZH2Ctrl (vehicle, n = 6; adriamycin, n = 5) and EZH2podKO (vehicle, n = 8; adriamycin, n = 11) mice. (G) Immunostaining for α-SMA in EZH2Ctrl (vehicle, n = 3; adriamycin, n = 4) and EZH2podKO (vehicle, n = 7; adriamycin, n = 8) mice 10 days after adriamycin injection. Original magnification, ×400. Black arrows label α-SMA immunoreactivity in glomerular cells of the adriamycin-injected EZH2podKO mouse. (H) Dual immunofluorescence for nephrin and the truncated Notch receptor N1-ICD in EZH2Ctrl (vehicle, n = 3; adriamycin, n = 3) and EZH2podKO (vehicle, n = 3; adriamycin, n = 3) mice 10 days after adriamycin injection. DAPI staining is shown in blue. Zoomed images are enlargements of the outlined areas. Original magnification, ×630. Values represent the mean ± SEM. *P < 0.05 and **P < 0.01, by 2-tailed Student’s t test (D) and 1-way ANOVA followed by Fisher’s LSD post-hoc test (F and G).