Functional Metabolomics Reveals that Astragalus Polysaccharides Improve Lipids Metabolism through Microbial Metabolite 2-Hydroxybutyric Acid in Obese Mice

Polysaccharides are widely present in herbs with multiple activities,especially immunity regulation and metabolic benefits for metabolic disorders.However,the underlying mechanisms are not well under-stood.Functional metabolomics is increasingly used to investigate systemic effects on the host by iden-tifying metabolites with particular functions.This study explores the mechanisms underlying the metabolic benefits of Astragalus polysaccharides(APS)by adopting a functional metabolomics strategy.The effects of APS were determined in eight-week high-fat diet(HFD)-fed obese mice.Then,gas chromatography–time-of-flight mass spectrometry(GC–TOFMS)-based untargeted metabolomics was performed for an analysis of serum and liver tissues,and liquid chromatography–tandem mass spectrom-etry(LC–MS/MS)-based targeted metabolomics was performed.The potential functions of the metabo-lites were tested with in vitro and in vivo models of metabolic disorders.Our results first confirmed the metabolic benefits of APS in obese mice.Then,metabolomics analysis revealed that APS supplemen-tation reversed the HFD-induced metabolic changes,and identified 2-hydroxybutyric acid(2-HB)as a potential functional metabolite for APS activity that was significantly decreased by a HFD and reversed by APS.Further study indicated that 2-HB inhibited oleic acid(OA)-induced triglyceride(TG)accumula-tion.It was also found to stimulate the expression of proteins in lipid degradation in hepatocytes and TG lipolysis in 3T3-L1 cells.Moreover,it was found to reduce serum TG and regulate the proteins involved in lipid degradation in high-fat and high-sucrose(HFHS)-fed mice.In conclusion,our study demonstrates that the metabolic benefits of APS are at least partially due to 2-HB generation,which modulated lipid metabolism both in vitro and in vivo.Our results also highlight that functional metabolomics is practical for investigating the mechanism underlying the systemic benefits of plant polysaccharides.

Osthole attenuates pulmonary arterial hypertension by modulation of phospholipid metabolism

OBJECTIVE Pulmonary arterial hypertension(PAH)is a malignant pulmonary vascular disease lacking efficacy therapeutics.Therefore,it urgently needs to develop safe and effective drugs for PAH treatment.Osthole derived from Cnidium monnieri(L.)Cusson(Shechuangzi)or Angelica pubescens Maxim(Duhuo)has the capacity to alleviate PAH by decreasing pulmonary arterial pressure and alleviating pulmonary vascular remodeling in rats,which is a candidate drug for the prevention of PAH,but the underlying modulatory mechanism is still unclear.Our study aims at investigating the metabolic modulatory mechanism of osthole against PAH employing functional metabolomics strategy.METHODS PAH model rats were successfully established with MCT,following osthole administration,then functional metabolomics based on untargeted metabolomics assay,targeted lipidomics analysis,qRT-PCR,Western blotting and ELISA were performed to investigate the modulatory mechanism of osthole against pulmonary arterial pressure and pulmonary vascular remodeling in PAH.RESULTS Untargeted metabolomics results found that sphingosine 1-phosphate(S1P)was the differential metabolites characterized PAH and reversed by osthole treatment.S1P is a crucial sphingolipid metabolite catalyzed by sphingosine kinases1(Sphk1)and functions as promoting PASMCs proliferation contributing to pulmonary vascular remodeling and pulmonary arterial pressure increase.We revealed that osthole reversed high level of S1P by modulating metabolic enzyme Sphk1 via inactivating microRNA-21-PI3K/Akt/mTOR signal pathway to decrease pulmonary arterial pressure in rats with PAH.Then,targeted phospholipid metabolomics results uncovered that decadienyl-L-carnitine(C10:2)was the differential metabolite characterized PAH and corrected by osthole treatment in rat with PAH.C10:2 is the intermediate metabolite of fatty acid oxidation(FAO),and C10:2 accumulation indicated mitochondrial dysfunction and FAO increase.CONCLUSION Osthole could block lipid metabolic reprogramming through functional modulating the expression of fatty acid translocase,fatty acid synthase,phospholipase A2,carnitine palmitoyltransferase 1A to inhibit C10:2,thus to improve mitochondrial dysfunction and inhibit utilizing lipid to biosynthesize necessary essence for pulmonary artery smooth muscle cells(PASMCs)proliferation.Moreover,we delineated that C10:2 and metabolic reprogramming enzymes were modulated by miRNA-22-3p which was involved in PASMCs proliferation and pulmonary vascular remodeling.Therefore,osthole inhibited miRNA-22-3p mediated lipid metabolic reprogramming to ameliorate pulmonary vascular remodeling.