PDGFB Inhibits The Differentiation Of Vascular Stem Cells Into Contractile Smooth Muscle Cells By Regulating The Notch3/NICD3 Pathway In Aortic Dissection

ObjectiveThe pathological features of aortic dissection(AD)are complex and diverse,including inflammation,immune injury,cellular senescence,and dysregulated phenotype of smooth muscle cells(SMCs).Resident vascular stem cells(VSCs)of the vascular adventitia can differentiate into contractile SMCs,complementing the loss of SMCs from vessels to maintain vascular homeostasis.However,the differentiation alternative role of vascular stem cells in aortic dissection patients remains unclear.This study aimed to reveal the characteristics of vascular injury in AD by single-cell sequencing and explore the role of platelet-derived growth factor B(PDGFB)during the differentiation of AD aortic VSCs into SMCs.MethodsUnderstanding the molecular processes occurring in different cell types in aortic vessels by single-cell sequencing and the search for potential target molecules by differential gene and functional enrichment analysis.Transforming growth factorβ1(TGF-β1)For in vitro induction of VSCs differentiation into vascular SMCs.Detection expression of phenotypic markers by immunofluorescence and Western blotting such as a-smooth muscle actin(a-SMA),calponinl(CNN1)and osteopontin(OPN).The level of PDGFB in serum was detected by ELISA kit.Sunitinib(PDGFB inhibitor)and DAPT(Notch3 inhibitor)were used for interventions in different experimental groupings.ResultsSingle cell sequencing data reveal aortic lesions in AD as well as significant cellular heterogeneity,including the accumulation of CD4+T cells,which leads to inflammation and cell death,and aberrant collagen formation mediated by fibroblasts.In addition,the results indicated that the percentage of VSCs present was reduced,and the ability to differentiate into contractile SMCs was inhibited.Finally,single-cell sequencing data demonstrate that the PDGF signaling pathway is activated in AD aorta.In vitro,VSCs derived SMCs in AD aorta display expression of contractile SMCs markers α-SMA,CNN1 was decreased,along with increased expression of OPN,a marker of synthetic SMCs.PDGFB expression is upregulated in the peripheral serum,tissues,and cells of patients with AD.Upregulation of PDGFB in SMCs derived from normal donor VSCs inhibits expression of a-SMA and CNN1.Furthermore,Notch3 expression was increased in aortic dissection as well as PDGFB upregulation.And,inhibition of Notch3 increases Expression of a-SMA,CNN1 and decreased expression of OPN in AD aortic VSCs derived SMCs.ConclusionsThe results of this study demonstrate cellular heterogeneity and injury characteristics of the aortic vasculature,including cell death,collagen deposition,and dysregulated signaling pathways.It was verified that PDGFB inhibited the expression of contractile proteins in AD aortic VSCs derived SMCs by upregulating Notch3 signaling pathway inhibition.Inhibition of PDGFB is a novel strategy to promote the differentiation of ad aortic VSCs into contractile SMCs to maintain vascular repair function.