Atraric acid attenuates chronic intermittent hypoxia-induced brain injury via AMPK-mediated Nrf2 and FoxO3a antioxidant pathway activation

Abstract

Background

Obstructive sleep apnea syndrome (OSAS), a chronic disorder affecting approximately 10 % of adults worldwide with heightened prevalence in males and obese populations, induces irreversible neurocognitive impairment. Atraric Acid (AA), a natural depside compound derived from lichens, exhibits dual functional properties through its molecular groups capable of free radical scavenging and metal chelation. However, its therapeutic potential in OSAS-related pathologies remains unexplored.

Objective

This study aims to investigate the neuroprotective effects and molecular mechanisms of AA against CIH-induced neuronal damage.

Methods

CIH mouse models and hypoxic injury models in HT22 neurons were established. AA was administered to mice at doses of 5, 10, and 20 mg/kg (selected based on literature references and preliminary experiments), and to cells at an optimal concentration of 20 μM (determined by CCK-8 assays). Therapeutic efficacy was evaluated through behavioral tests including the Morris Water Maze, Elevated Plus Maze, and Open Field Test. Neuroprotective effects were assessed via histopathological examination (e.g., neuronal survival in hippocampal CA3 and DG sub-regions) and detection of oxidative stress/ferroptosis markers (e.g., MDA levels, GPX4 expression, and related biomarkers). Transcriptomic sequencing and molecular docking analyses were employed to investigate differentially expressed genes, pathway enrichment, and underlying mechanisms.

Results

In vivo and in vitro experiments demonstrated that AA significantly alleviated neuronal damage in CIH mice and enhanced HT22 cell viability. AA down-regulated oxidative stress- and ferroptosis-related gene expression. Transcriptomic sequencing identified AMPK signaling as a key target. Combined AMPK inhibitor (Compound C) and nuclear-cytoplasmic fractionation experiments confirmed that AA synergistically regulates dual antioxidant pathways (Nrf2/HO-1 and FoxO3a/SOD2) via AMPK activation.

Conclusion

AA mitigates CIH-induced neurocognitive impairment by AMPK-dependent activation of the Nrf2/HO-1 and FoxO3a/SOD2 axes, establishing a dual antioxidant-ferroptosis defense barrier. This study is the first to systematically elucidate AA's molecular mechanisms using transcriptomics data integrated with computational simulations, providing novel therapeutic targets and a translational paradigm for developing natural compound-based therapies for OSAS.