Aurantio-obtusin improves obesity and protects hepatic inflammation by rescuing mitochondrial damage in overwhelmed brown adipose tissue.

Background: Obesity is frequently linked to chronic systamic inflammation and presents significant challenges to public health. Aurantio-obtusin (AO) boosted the brown adipose tissue (BAT) thermogenesis in diet-induced obesity. However, the specific mechanisms by which injured mitochondria-related damage signals derived from overwhelmed BAT can transmit to liver and exacerbate metabolic disorders and whether AO can reverse this process remain unknown.

Materials and methods: After applying high-fat diet and glucose-fructose water (HFHS)-induced obesity mice, different BAT transplant procedures and primary BAT adipocytes, we investigated the anti-obesity effects and mechanism of AO through RNA sequencing and biology techniques.

Results: AO improved whole-body lipid accumulation, mitochondrial metabolism in BAT and hepatic inflammation in HFHS-induced obesity mice. Interscapular transplant of BAT-derived from obese donor mice triggered hepatic inflammation of chow diet-fed recipient mice, which was protected by AO. Furthermore, the transplantation of BAT-derived from AO-treated mice protected hepatic inflammation in obese mice. In vivo and in lipid-challenged primary BAT adipocytes, AO decreased kexin type 9 (PCSK9), prevented mPTP opening and mitochondrial DNA (mtDNA) release in extracellular vesicles (EVs) manner by inhibiting the acetylation of cyclophilin D associated with adenine nucleotide translocase, suppressing oligomerization of voltage-dependent anion channel 1 and activating mitophagy. Ultimately, AO inhibited mtDNA-containing EVs-induced cyclic GMP-AMP synthase/stimulator of interferon genes (STING) activation and hepatic inflammation, which was confirmed by Sting^-/- mice.

Conclusion: AO not only improves thermogenesis and mitochondrial function of BAT but also prevents liver inflammation by repairing mitochondrial function and blocking the transfer of mtDNA from BAT to the liver.