Vascular smooth muscle cell(VSMC)degeneration is a major mechanism underlying abdominal aortic aneurysm(AAA)formation.However,the upstream signaling pathways that converge on the transcriptional machinery to drive VSM...Vascular smooth muscle cell(VSMC)degeneration is a major mechanism underlying abdominal aortic aneurysm(AAA)formation.However,the upstream signaling pathways that converge on the transcriptional machinery to drive VSMC degeneration remain elusive.Here,we integrated single-nucleus(sn)multi-omics,chromatin immunoprecipitation(ChIP)-seq,and wet lab validation to identify transcriptional effectors of VSMC-MAPK14,which we previously reported to promote AAA.Compared with wild-type(WT)mice,VSMC-Mapk14 knockout(KO)mice displayed reduced VSMC degeneration,as evidenced by decreased expression of markers of endoplasmic reticulum stress,the unfolded protein response,fibrosis,and apoptosis,after 7 days of Ang II infusion.SnRNA-seq revealed increased VSMCs and reduced fibroblast and immune cell populations in KOs.Reclustering VSMCs revealed an increased proportion of contractile cluster and a reduced proportion of fibrotic cluster in KOs.The VSMC differentiation gene program and upstream pathways were upregulated,whereas degeneration pathways,including extracellular matrix remodeling,inflammation,and apoptosis,were downregulated in KO VSMCs.snATAC-seq and validation revealed increased serum response factor(SRF)motif activity and expression but reduced RUNX2 expression in KO VSMCs.Integrative analysis of snATAC-seq,ChIP-seq,and bulk RNAseq identified the MYOCD/SRF/CArG triad as the driver of the contractile gene program following Mapk14 loss.We further found that the expression of Bcl2,a novel MYOCD/SRF/CArG target,was increased in Mapk14 KO VSMCs.Loss of Mapk14 attenuated MRTFA protein abundance via increased ubiquitin‒proteasome degradation,which was attributed to reduced USP10 protein expression.These findings reveal MAPK14-driven transcriptomic and epigenomic landscapes that promote VSMC degeneration by suppressing SRF/MYOCD/CArG while activating RUNX2 and MRTFA.Our study provides mechanistic insight into MAPK14-mediated VSMC degeneration and provides a basis for MAPK14-targeted therapeutic strategies for AAA.展开更多
基金supported by National Institutes of Health R01HL122686,R01HL139794,R01HL170024 and Augusta University faculty startup funding to X.L.,HL147476 to J.M.M.,and HL164792 to G.C.R01DK121227,R01DK132888 and I01 BX006080 to R.V.P.+3 种基金R01 HL146103,HL167201,AG082839 and VA BX005800,BX004426,BX006321 to Y.C.grants from the American Heart Association TPA1141836,SCEFIA1156682 and CDA34110319 to W.Z.a Postdoctoral Fellowship 915887 to N.I.grants from the National Research,Development and Innovation Office of Hungary NKFI-ADVANC149634 to P.S.We thank the Genomics Research Center at the University of Rochester for performing the ChIP-seq,Sequencing and Gene Editing Core at the University of Houston for snRNA-seq and the Genomics Core Georgia Cancer Center for snATACseq experiments.We thank the Electron Microscopy and Histology Core at Augusta University for their assistance with the TEM studies.
文摘Vascular smooth muscle cell(VSMC)degeneration is a major mechanism underlying abdominal aortic aneurysm(AAA)formation.However,the upstream signaling pathways that converge on the transcriptional machinery to drive VSMC degeneration remain elusive.Here,we integrated single-nucleus(sn)multi-omics,chromatin immunoprecipitation(ChIP)-seq,and wet lab validation to identify transcriptional effectors of VSMC-MAPK14,which we previously reported to promote AAA.Compared with wild-type(WT)mice,VSMC-Mapk14 knockout(KO)mice displayed reduced VSMC degeneration,as evidenced by decreased expression of markers of endoplasmic reticulum stress,the unfolded protein response,fibrosis,and apoptosis,after 7 days of Ang II infusion.SnRNA-seq revealed increased VSMCs and reduced fibroblast and immune cell populations in KOs.Reclustering VSMCs revealed an increased proportion of contractile cluster and a reduced proportion of fibrotic cluster in KOs.The VSMC differentiation gene program and upstream pathways were upregulated,whereas degeneration pathways,including extracellular matrix remodeling,inflammation,and apoptosis,were downregulated in KO VSMCs.snATAC-seq and validation revealed increased serum response factor(SRF)motif activity and expression but reduced RUNX2 expression in KO VSMCs.Integrative analysis of snATAC-seq,ChIP-seq,and bulk RNAseq identified the MYOCD/SRF/CArG triad as the driver of the contractile gene program following Mapk14 loss.We further found that the expression of Bcl2,a novel MYOCD/SRF/CArG target,was increased in Mapk14 KO VSMCs.Loss of Mapk14 attenuated MRTFA protein abundance via increased ubiquitin‒proteasome degradation,which was attributed to reduced USP10 protein expression.These findings reveal MAPK14-driven transcriptomic and epigenomic landscapes that promote VSMC degeneration by suppressing SRF/MYOCD/CArG while activating RUNX2 and MRTFA.Our study provides mechanistic insight into MAPK14-mediated VSMC degeneration and provides a basis for MAPK14-targeted therapeutic strategies for AAA.
