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.

Abscisic acid-dependent PMT1 expression regulates salt tolerance by alleviating abscisic acid-mediated reactive oxygen species production in Arabidopsis

Phosphocholine(PCho)is an intermediate metabolite of nonplastid plant membranes that is essential for salt tolerance.However,how PCho metabolism modulates response to salt stress remains unknown.Here,we characterize the role of phosphoethanolamine N-methyltransferase 1(PMT1)in salt stress tolerance in Arabidopsis thaliana using a T-DNA insertional mutant,geneediting alleles,and complemented lines.The pmt1 mutants showed a severe inhibition of root elongation when exposed to salt stress,but exogenous ChoCl or lecithin rescued this defect.pmt1 also displayed altered glycerolipid metabolism under salt stress,suggesting that glycerolipids contribute to salt tolerance.Moreover,pmt1 mutants exhibited altered reactive oxygen species(ROS)accumulation and distribution,reduced cell division activity,and disturbed auxin distribution in the primary root compared with wild-type seedlings.We show that PMT1 expression is induced by salt stress and relies on the abscisic acid(ABA)signaling pathway,as this induction was abolished in the aba2-1 and pyl112458 mutants.However,ABA aggravated the salt sensitivity of the pmt1 mutants by perturbing ROS distribution in the root tip.Taken together,we propose that PMT1 is an important phosphoethanolamine N-methyltransferase participating in root development of primary root elongation under salt stress conditions by balancing ROS production and distribution through ABA signaling.