Disordered hepatic glucagon response contributes to hyperglycemia in diabetes. The regulators involved in glucagon response are less understood. This work aims to investigate the roles of mitochondrial β-oxidation enzyme HADHA and its downstream ketone bodies in hepatic glucagon response. Here we show that glucagon challenge impairs expression of HADHA. Liver-specific HADHA overexpression reversed hepatic gluconeogenesis in mice, while HADHA knockdown augmented glucagon response. Stable isotope tracing shows that HADHA promotes ketone body production via β-oxidation. The ketone body β-hydroxybutyrate (BHB) but not acetoacetate suppresses gluconeogenesis by selectively inhibiting HDAC7 activity via interaction with Glu543 site to facilitate FOXO1 nuclear exclusion. In HFD-fed mice, HADHA overexpression improved metabolic disorders, and these effects are abrogated by knockdown of BHB-producing enzyme. In conclusion, BHB is responsible for the inhibitory effect of HADHA on hepatic glucagon response, suggesting that HADHA activation or BHB elevation by pharmacological intervention hold promise in treating diabetes.
Radix Aconiti Lateralis Preparata (Fuzi in Chinese) is an efficient Chinese herbal medicine (CHM) against doxorubicin (DOX)-induced cardiomyopathy (DIC), but the cardioprotective compounds and targets of Fuzi remain unclear. In this work, a novel two-dimensional (2D) polyamidoamine (PAMAM)-modified cardiac mitochondrial membrane chromatography (CMMC) system, with the characteristic of high-density mitochondrial membrane coating and longer column lifespan, was developed for the identification of bioactive components from Fuzi to counteract DIC. Three compounds with strong retention were screened out to have cardioprotective effects against DOX-induced cardiotoxicity in different cardiomyocytes, and one promising compound songorine with the highest affinity was selected for further in vitro and in vivo pharmacodynamic validation and target identification. Hadha, involved in fatty acid oxidation (FAO) and apoptosis, was identified as the functional target of songorine by cardiac mitochondria proteomics, drug affinity responsive target stability (DARTS), cellular thermal shift assay (CETSA), surface plasmon resonance (SPR) and molecular docking assays. siRNA experiments have also demonstrated that songorine can affect the function of Hadha. It was concluded that songorine could directly bind to the Hadha protein to alleviate the functional impairment of the mitochondrial FAO and oxidative phosphorylation (OXPHOS) and regulate the Bcl-2 family proteins in mice to treat DIC.
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