GTP Cyclohydrolase 1/Tetrahydrobiopterin Counteract Ferroptosis through Lipid Remodeling

TLDR

Ferroptosis is an iron‑dependent regulated cell death that links iron, lipid, and glutathione metabolism to degenerative diseases and tumor suppression. A genome‑wide activation screen identified GTP cyclohydrolase‑1 (GCH1) and its metabolites BH4/BH2 as key genes that counter ferroptosis. GCH1‑mediated synthesis of BH4/BH2 remodels phospholipids, preventing loss of PUFA‑containing phospholipids and conferring ferroptosis resistance through a BH4‑CoQ10‑phospholipid axis that operates independently of the GPX4/glutathione system.

Abstract

Ferroptosis is an iron-dependent form of regulated cell death linking iron, lipid, and glutathione levels to degenerative processes and tumor suppression. By performing a genome-wide activation screen, we identified a cohort of genes antagonizing ferroptotic cell death, including GTP cyclohydrolase-1 (GCH1) and its metabolic derivatives tetrahydrobiopterin/dihydrobiopterin (BH4/BH2). Synthesis of BH4/BH2 by GCH1-expressing cells caused lipid remodeling, suppressing ferroptosis by selectively preventing depletion of phospholipids with two polyunsaturated fatty acyl tails. GCH1 expression level in cancer cell lines stratified susceptibility to ferroptosis, in accordance with its expression in human tumor samples. The GCH1-BH4-phospholipid axis acts as a master regulator of ferroptosis resistance, controlling endogenous production of the antioxidant BH4, abundance of CoQ10, and peroxidation of unusual phospholipids with two polyunsaturated fatty acyl tails. This demonstrates a unique mechanism of ferroptosis protection that is independent of the GPX4/glutathione system.