Hif-2α promotes degradation of mammalian peroxisomes by selective autophagy

Cell Metab. 2014 Nov 4;20(5):882-897. doi: 10.1016/j.cmet.2014.09.017. Epub 2014 Nov 4.

Abstract

Peroxisomes play a central role in lipid metabolism, and their function depends on molecular oxygen. Low oxygen tension or von Hippel-Lindau (Vhl) tumor suppressor loss is known to stabilize hypoxia-inducible factors alpha (Hif-1α and Hif-2α) to mediate adaptive responses, but it remains unknown if peroxisome homeostasis and metabolism are interconnected with Hif-α signaling. By studying liver-specific Vhl, Vhl/Hif1α, and Vhl/Hif2α knockout mice, we demonstrate a regulatory function of Hif-2α signaling on peroxisomes. Hif-2α activation augments peroxisome turnover by selective autophagy (pexophagy) and thereby changes lipid composition reminiscent of peroxisomal disorders. The autophagy receptor Nbr1 localizes to peroxisomes and is likewise degraded by Hif-2α-mediated pexophagy. Furthermore, we demonstrate that peroxisome abundance is reduced in VHL-deficient human clear cell renal cell carcinomas with high HIF-2α levels. These results establish Hif-2α as a negative regulator of peroxisome abundance and metabolism and suggest a mechanism by which cells attune peroxisomal function with oxygen availability.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy*
  • Basic Helix-Loop-Helix Transcription Factors / genetics
  • Basic Helix-Loop-Helix Transcription Factors / metabolism*
  • Carcinoma, Renal Cell / genetics
  • Carcinoma, Renal Cell / metabolism
  • Cell Line, Tumor
  • Gene Deletion
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Kidney / metabolism
  • Kidney Neoplasms / genetics
  • Kidney Neoplasms / metabolism
  • Mice
  • Mice, Knockout
  • Peroxisomes / genetics
  • Peroxisomes / metabolism*
  • Von Hippel-Lindau Tumor Suppressor Protein / genetics
  • Von Hippel-Lindau Tumor Suppressor Protein / metabolism

Substances

  • Basic Helix-Loop-Helix Transcription Factors
  • endothelial PAS domain-containing protein 1
  • Von Hippel-Lindau Tumor Suppressor Protein