Polysulfide inhibits hypoxia-elicited hypoxia-inducible factor activation in a mitochondria-dependent manner

Abstract

In cellular signaling, the diverse physiological actions of biological gases, including O₂, CO, NO, and H₂S, have attracted much interest. Hypoxia-inducible factors (HIFs), including HIF-1 and HIF-2, are transcription factors that respond to reduced intracellular O₂ availability. Polysulfides are substances containing varying numbers of sulfur atoms (H₂S_n) that are generated endogenously from H₂S by 3-mercaptopyruvate sulfurtransferase in the presence of O₂, and regulate ion channels, specific tumor suppressors, and protein kinases. However, the effect of polysulfides on HIF activation in hypoxic mammalian cells is largely unknown. Here, we have investigated the effect of polysulfide on cells in vitro. In established cell lines, polysulfide donors reversibly reduced cellular O₂ consumption and inhibited hypoxia-induced HIF-1α protein accumulation and the expression of genes downstream of HIFs; however, these effects were not observed in anoxia. In Von Hippel-Lindau tumor suppressor (VHL)- and mitochondria-deficient cells, polysulfides did not affect HIF-1α protein synthesis but destabilized it in a VHL- and mitochondria-dependent manner. For the first time, we show that polysulfides modulate intracellular O₂ homeostasis and regulate HIF activation and subsequent hypoxia-induced gene expression in a VHL- and mitochondria-dependent manner.

Keywords: Electron Transport Chain; Hydrogen sulfide; Hypoxia-inducible factor; Mitochondria; Oxygen consumption; Polysulfide; RNA-Seq; Sulfane sulfur; VHL; ρ0 cell.