High glucose-stimulated enhancer of zeste homolog-2 (EZH2) forces suppression of deptor to cause glomerular mesangial cell pathology

Falguni Das, Amit Bera, Nandini Ghosh-Choudhury, Kavitha Sataranatarajan, Amrita Kamat, Balakuntalam S. Kasinath, Goutam Ghosh Choudhury

Research output: Contribution to journalArticlepeer-review

Abstract

Function of mTORC1 and mTORC2 has emerged as a driver of mesangial cell pathologies in diabetic nephropathy. The mechanism of mTOR activation is poorly understood in this disease. Deptor is a constitutive subunit and a negative regulator of both mTOR complexes. Mechanistic investigation in mesangial cells revealed that high glucose decreased the expression of deptor concomitant with increased mTORC1 and mTORC2 activities, induction of hypertrophy and, expression of fibronectin and PAI-1. shRNAs against deptor mimicked these pathologic outcomes of high glucose. Conversely, overexpression of deptor significantly inhibited all effects of high glucose. To determine the mechanism of deptor suppression, we found that high glucose significantly increased the expression of EZH2, resulting in lysine-27 tri-methylation of histone H3 (H3K27Me3). Employing approaches including pharmacological inhibition, shRNA-mediated downregulation and overexpression of EZH2, we found that EZH2 regulates high glucose-induced deptor suppression along with activation of mTOR, mesangial cell hypertrophy and fibronectin/PAI-1 expression. Moreover, expression of hyperactive mTORC1 reversed shEZH2-mediated inhibition of hypertrophy and expression of fibronectin and PAI-1 by high glucose. Finally, in renal cortex of diabetic mice, we found that enhanced expression of EZH2 is associated with decreased deptor levels and increased mTOR activity and, expression of fibronectin and PAI-1. Together, our findings provide a novel mechanism for mTOR activation via EZH2 to induce mesangial cell hypertrophy and matrix expansion during early progression of diabetic nephropathy. These results suggest a strategy for leveraging the intrinsic effect of deptor to suppress mTOR activity via reducing EZH2 as a novel therapy for diabetic nephropathy.

Original languageEnglish (US)
Article number110072
JournalCellular Signalling
Volume86
DOIs
StatePublished - Oct 2021
Externally publishedYes

Keywords

  • Diabetic renal hypertrophy
  • Kidney
  • Matrix expansion, EZH2, deptor
  • mTORC1

ASJC Scopus subject areas

  • Cell Biology

Fingerprint

Dive into the research topics of 'High glucose-stimulated enhancer of zeste homolog-2 (EZH2) forces suppression of deptor to cause glomerular mesangial cell pathology'. Together they form a unique fingerprint.

Cite this