Protective effects of klotho on palmitate-induced podocyte injury in diabetic nephropathy

PLoS One. 2021 Apr 23;16(4):e0250666. doi: 10.1371/journal.pone.0250666. eCollection 2021.

Abstract

The anti-aging gene, klotho, has been identified as a multi-functional humoral factor and is implicated in multiple biological processes. However, the effects of klotho on podocyte injury in diabetic nephropathy are poorly understood. Thus, the current study aims to investigate the renoprotective effects of klotho against podocyte injury in diabetic nephropathy. We examined lipid accumulation and klotho expression in the kidneys of diabetic patients and animals. We stimulated cultured mouse podocytes with palmitate to induce lipotoxicity-mediated podocyte injury with or without recombinant klotho. Klotho level was decreased in podocytes of lipid-accumulated obese diabetic kidneys and palmitate-treated mouse podocytes. Palmitate-treated podocytes showed increased apoptosis, intracellular ROS, ER stress, inflammation, and fibrosis, and these were significantly attenuated by klotho administration. Klotho treatment restored palmitate-induced downregulation of the antioxidant molecules, Nrf2, Keap1, and SOD1. Klotho inhibited the phosphorylation of FOXO3a, promoted its nuclear translocation, and then upregulated MnSOD expression. In addition, klotho administration attenuated palmitate-induced cytoskeleton changes, decreased nephrin expression, and increased TRPC6 expression, eventually improving podocyte albumin permeability. These results suggest that klotho administration prevents palmitate-induced functional and morphological podocyte injuries, and this may indicate that klotho is a potential therapeutic agent for the treatment of podocyte injury in obese diabetic nephropathy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects*
  • Cytokines / metabolism
  • Diabetic Nephropathies / pathology*
  • Down-Regulation / drug effects
  • Forkhead Box Protein O3 / metabolism
  • Glucuronidase / genetics
  • Glucuronidase / metabolism
  • Glucuronidase / pharmacology*
  • Humans
  • Kelch-Like ECH-Associated Protein 1 / genetics
  • Kelch-Like ECH-Associated Protein 1 / metabolism
  • Klotho Proteins
  • Mice
  • Mice, Obese
  • NF-E2-Related Factor 2 / genetics
  • NF-E2-Related Factor 2 / metabolism
  • Oxidative Stress / drug effects
  • Palmitates / pharmacology*
  • Podocytes / cytology
  • Podocytes / drug effects
  • Podocytes / metabolism
  • Reactive Oxygen Species / metabolism
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / pharmacology
  • Superoxide Dismutase / genetics
  • Superoxide Dismutase / metabolism
  • TRPC6 Cation Channel / genetics
  • TRPC6 Cation Channel / metabolism
  • Up-Regulation / drug effects

Substances

  • Cytokines
  • Forkhead Box Protein O3
  • FoxO3 protein, mouse
  • Kelch-Like ECH-Associated Protein 1
  • NF-E2-Related Factor 2
  • Palmitates
  • Reactive Oxygen Species
  • Recombinant Proteins
  • TRPC6 Cation Channel
  • Superoxide Dismutase
  • Glucuronidase
  • Klotho Proteins

Grants and funding

This work was supported by the National Research Foundation (NRF) of Korea grant funded by the Korea government (MSIT) (2020R1A2C2003438, 2019M3E5D1A02069071, 2018R1A2B6005360) and the Ministry of Education (2018R1A6A3A11040860). It was also supported by Soonchunhyang University Research Fund. The authors declare no conflicts of interest.