Mitochondrial DNA-cGAS-STING-CISD1 axis mediates hypoxia-induced cognitive impairment by driving hippocampal neuronal ferroptosis

Abstract High-altitude hypoxic cognitive impairment severely compromises the physical and mental health of individuals who rapidly ascend to or reside long-term at high altitude; however, its initiating mechanisms, pathological cascades, and molecular regulatory network remain incompletely understood, leaving a paucity of effective therapeutic targets and preventive strategies. Using a mouse model of simulated 6000 m hypobaric hypoxia and a primary hippocampal neuron hypoxia model, we integrated behavioral testing, transmission electron microscopy, Seahorse metabolic analysis, transcriptomic profiling, co-immunoprecipitation-coupled proteomics, structural prediction, pharmacological intervention, and clinical validation in human cohorts to systematically delineate the molecular mechanisms and core regulatory pathways underlying hypoxia-induced neuronal ferroptosis. Hypoxic exposure time-dependently impaired object recognition and spatial memory in mice and caused hippocampal neuron loss. Mechanistically, mitochondrial damage emerged as a critical initiating event during hypoxic stress, triggering mitochondrial DNA (mtDNA) release and subsequent activation of the cGAS-STING signaling pathway. Hypoxic hippocampal neurons exhibited canonical features of ferroptosis, including elevated Fe²⁺ and malondialdehyde (MDA) levels, decreased GPX4 expression, and enhanced ACSL4 expression and increased mitochondrial C11-BODIPY oxidation. Pharmacological inhibition of STING with C-176 significantly alleviated these ferroptosis phenotypes, neuronal loss, and cognitive impairment. Co-immunoprecipitation combined with proteomics identified CISD1 (mitoNEET), a mitochondrial outer membrane protein, as a STING-interacting partner, and their binding was enhanced under hypoxia and localized to mitochondria-endoplasmic reticulum contact sites. Moreover, the ferroptosis inhibitor Liproxstatin-1 rescued hypoxic cognitive impairment and partially restored mitochondrial morphology and respiratory function without reversing STING phosphorylation, indicating that ferroptosis functions downstream of STING and constitutes a feed-forward amplification loop by aggravating mitochondrial damage. In human cohorts, levels of serum iron and oxidative damage markers correlated positively with residential altitude. Collectively, these findings establish a self-amplifying pathological axis of mitochondrial damage-mtDNA-cGAS-STING-CISD1-ferroptosis, and targeting this axis may provide novel strategies for the prevention and treatment of high-altitude hypoxic cognitive impairment.