1. Academic Validation
  2. Molecular mechanism of ectopic lipid accumulation induced by methylglyoxal via activation of the NRF2/PI3K/AKT pathway implicates renal lipotoxicity caused by diabetes mellitus

Molecular mechanism of ectopic lipid accumulation induced by methylglyoxal via activation of the NRF2/PI3K/AKT pathway implicates renal lipotoxicity caused by diabetes mellitus

  • PLoS One. 2024 Oct 16;19(10):e0306575. doi: 10.1371/journal.pone.0306575.
Chiung Chi Peng 1 Eugene Chang Yu Chen 1 2 Chang-Rong Chen 1 Charng-Cherng Chyau 3 Kuan-Chou Chen 1 4 5 Robert Y Peng 3
Affiliations

Affiliations

  • 1 Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
  • 2 MD Program, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America.
  • 3 Department of Biotechnology, College of Medical and Health Care, Hungkuang University, Shalu District, Taichung, Taiwan.
  • 4 Department of Urology, Taipei Medical University Shuang-Ho Hospital, Zhong-He District, New Taipei City, Taiwan.
  • 5 TMU-Research Center of Urology and Kidney, Taipei Medical University, Taipei, Taiwan.
Abstract

Patients with chronic kidney disease (CKD) have a high incidence of dyslipidemia comprising high triglyceride (TG) and low high-density lipoprotein (HDL)-cholesterol levels. An abnormal increase of TGs within cells can lead to intracellular lipid accumulation. In addition to dyslipidemia, hyperglycemia in diabetes may elicit ectopic lipid deposition in non-adipose tissues. Hyperglycemia increases intracellular levels of methylglyoxal (MG) leading to cellular dysfunction. A deficit of glyoxalase I (GLO1) contributes to dicarbonyl stress. Whether dicarbonyl stress induced by MG causes renal lipotoxicity through alteration of lipid metabolism signaling is still unknown. In this study, mice with high fat diet-induced diabetes were used to investigate the renal pathology induced by MG. NRK52E cells treated with MG were further used in vitro to delineate the involvement of lipogenic signaling. After treatment with MG for 12 weeks, plasma TG levels, renal fatty changes, and tubular injuries were aggravated in diabetic mice. In NRK52E cells, MG activated the nuclear factor erythroid 2-related factor 2 (Nrf2)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) and sterol regulatory element-binding protein 1 (SREBP1), resulting in stimulation of fatty acid synthase. The intracellular accumulation of lipid droplets was mainly contributed by TGs, which increased the oxidative stress accompanied by high Nrf2 expression. In addition, MG time-dependently activated cyclin D, cyclin-dependent kinase 4 (CDK4), and cleaved Caspase-3, evidencing that G0/G1 arrest was associated with Apoptosis of NRK52E cells. In conclusion, our studies revealed the mechanism of lipotoxicity caused by MG. The target of such dicarbonyl stress may become a promising therapy for diabetic CKD.

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