Sleep deprivation (SD) triggers mitochondrial dysfunction and neural inflammation, leading to cognitive impairment and mental issues. However, the mechanism involving mitochondrial dysfunction and neural inflammation still remains unclear. Here, we report that SD rats exhibited multiple behavioral disorders, brain oxidative stress, and robust brain mitochondrial DNA (mtDNA) oxidation. In particular, SD activated microglia and microglial mtDNA efflux to the cytosol and provoked brain pro-inflammatory cytokines. We observed that the mtDNA efflux and pro-inflammatory cytokines significantly reduced with the suppression of the mtDNA oxidation. With the treatment of a novel mitochondrial nutrient, hydroxytyrosol butyrate (HTHB), the SD-induced behavioral disorders were significantly ameliorated while mtDNA oxidation, mtDNA release, and NF-κB activation were remarkably alleviated in both the rat brain and the N9 microglial cell line. Together, these results indicate that microglial mtDNA oxidation and the resultant release induced by SD mediate neural inflammation and HTHB prevents mtDNA oxidation and efflux, providing a potential treatment for SD-induced mental issues.

Neuroinflammation driven by microglial activation is a hallmark of Alzheimer’s disease (AD). Triggering receptor expressed on myeloid cells 2 (TREM2) is a key regulator of microglial inflammation, yet strategies to modulate its expression remain limited. Safflower leaves, a vegetable rich in flavonoids—particularly luteolin—were previously shown to attenuate neuroinflammation, reduce oxidative stress, and ameliorate cognitive impairment in APP/PS1 mice. Here, we demonstrated that safflower leaves inhibit microglial inflammation and upregulate TREM2 in APP/PS1 mice. Luteolin, the major active flavonoid in safflower leaves, exerted anti-inflammatory effects in lipopolysaccharides (LPS)-activated microglia. Mechanistically, luteolin enhanced Trem2 transcription by activating forkhead box protein O3 (FOXO3), a novel transcriptional regulator of Trem2 identified through promoter analysis. FOXO3 binding to the Trem2 promoter was essential for this regulation, and luteolin further promoted FOXO3 nuclear translocation. Crucially, Trem2 knockdown attenuated luteolin’s anti-inflammatory effects, confirming TREM2 as a key mediator. Overall, our study reveals the FOXO3-TREM2 axis as a potential therapeutic target for neuroinflammation and highlights luteolin present in safflower leaves as a candidate dietary intervention for AD, providing new mechanistic insights into the anti-inflammatory activity of this natural antioxidant.