title: Smad4 Deficiency in Smooth Muscle Cells Initiates the Formation of Aortic Aneurysm.
abstract: BACKGROUND
  Aortic aneurysm is a life-threatening cardiovascular disorder caused by the predisposition for dissection and rupture. Genetic studies have proved the involvement of the transforming growth factor-β (TGF-β) pathway in aortic aneurysm. Smad4 is the central mediator of the canonical TGF-β signaling pathway. However, the exact role of Smad4 in smooth muscle cells (SMCs) leading to the pathogenesis of aortic aneurysms is largely unknown.
  
  
  OBJECTIVE
  To determine the role of smooth muscle Smad4 in the pathogenesis of aortic aneurysms.
  
  
  RESULTS
  Conditional gene knockout strategy combined with histology and expression analysis showed that Smad4 or TGF-β receptor type II deficiency in SMCs led to the occurrence of aortic aneurysms along with an upregulation of cathepsin S and matrix metallopeptidase-12, which are proteases essential for elastin degradation. We further demonstrated a previously unknown downregulation of matrix metallopeptidase-12 by TGF-β in the aortic SMCs, which is largely abrogated in the absence of Smad4. Chemotactic assay and pharmacologic treatment demonstrated that Smad4-deficient SMCs directly triggered aortic wall inflammation via the excessive production of chemokines to recruit macrophages. Monocyte/macrophage depletion or blocking selective chemokine axis largely abrogated the progression of aortic aneurysm caused by Smad4 deficiency in SMCs.
  
  
  CONCLUSIONS
  The findings reveal that Smad4-dependent TGF-β signaling in SMCs protects against aortic aneurysm formation and dissection. The data also suggest important implications for novel therapeutic strategies to limit the progression of the aneurysm resulting from TGF-β signaling loss-of-function mutations.
authors.affiliation: From the State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Diseases, Institute of Biotechnology, Beijing, PR China (P.Z., S.H., J.C., J.Z., F.L., R.J., X.C., Y.L., X.Y.); Model Organism Division, E-institutes of Shanghai Universities, Shanghai Jiaotong University, Shanghai, PR China (P.Z., J.C., X.Y.); Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing, PR China (X.M., Y.S., Y.Z.); Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study and School of Medicine, Nanjing University, Nanjing, PR China (M.Z.); and Beijing AnZhen Hospital, Affiliated to Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Diseases, The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Beijing, PR China (J.D.).
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: From the State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Diseases, Institute of Biotechnology, Beijing, PR China (P.Z., S.H., J.C., J.Z., F.L., R.J., X.C., Y.L., X.Y.); Model Organism Division, E-institutes of Shanghai Universities, Shanghai Jiaotong University, Shanghai, PR China (P.Z., J.C., X.Y.); Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing, PR China (X.M., Y.S., Y.Z.); Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study and School of Medicine, Nanjing University, Nanjing, PR China (M.Z.); and Beijing AnZhen Hospital, Affiliated to Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Diseases, The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Beijing, PR China (J.D.).
authors.forename: Siyuan
authors.initials: S
authors.lastname: Hou
authors.affiliation: From the State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Diseases, Institute of Biotechnology, Beijing, PR China (P.Z., S.H., J.C., J.Z., F.L., R.J., X.C., Y.L., X.Y.); Model Organism Division, E-institutes of Shanghai Universities, Shanghai Jiaotong University, Shanghai, PR China (P.Z., J.C., X.Y.); Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing, PR China (X.M., Y.S., Y.Z.); Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study and School of Medicine, Nanjing University, Nanjing, PR China (M.Z.); and Beijing AnZhen Hospital, Affiliated to Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Diseases, The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Beijing, PR China (J.D.).
authors.forename: Jicheng
authors.initials: J
authors.lastname: Chen
authors.affiliation: From the State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Diseases, Institute of Biotechnology, Beijing, PR China (P.Z., S.H., J.C., J.Z., F.L., R.J., X.C., Y.L., X.Y.); Model Organism Division, E-institutes of Shanghai Universities, Shanghai Jiaotong University, Shanghai, PR China (P.Z., J.C., X.Y.); Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing, PR China (X.M., Y.S., Y.Z.); Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study and School of Medicine, Nanjing University, Nanjing, PR China (M.Z.); and Beijing AnZhen Hospital, Affiliated to Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Diseases, The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Beijing, PR China (J.D.).
authors.forename: Jishuai
authors.initials: J
authors.lastname: Zhang
authors.affiliation: From the State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Diseases, Institute of Biotechnology, Beijing, PR China (P.Z., S.H., J.C., J.Z., F.L., R.J., X.C., Y.L., X.Y.); Model Organism Division, E-institutes of Shanghai Universities, Shanghai Jiaotong University, Shanghai, PR China (P.Z., J.C., X.Y.); Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing, PR China (X.M., Y.S., Y.Z.); Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study and School of Medicine, Nanjing University, Nanjing, PR China (M.Z.); and Beijing AnZhen Hospital, Affiliated to Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Diseases, The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Beijing, PR China (J.D.).
authors.forename: Fuyu
authors.initials: F
authors.lastname: Lin
authors.affiliation: From the State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Diseases, Institute of Biotechnology, Beijing, PR China (P.Z., S.H., J.C., J.Z., F.L., R.J., X.C., Y.L., X.Y.); Model Organism Division, E-institutes of Shanghai Universities, Shanghai Jiaotong University, Shanghai, PR China (P.Z., J.C., X.Y.); Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing, PR China (X.M., Y.S., Y.Z.); Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study and School of Medicine, Nanjing University, Nanjing, PR China (M.Z.); and Beijing AnZhen Hospital, Affiliated to Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Diseases, The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Beijing, PR China (J.D.).
authors.forename: Renjie
authors.initials: R
authors.lastname: Ju
authors.affiliation: From the State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Diseases, Institute of Biotechnology, Beijing, PR China (P.Z., S.H., J.C., J.Z., F.L., R.J., X.C., Y.L., X.Y.); Model Organism Division, E-institutes of Shanghai Universities, Shanghai Jiaotong University, Shanghai, PR China (P.Z., J.C., X.Y.); Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing, PR China (X.M., Y.S., Y.Z.); Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study and School of Medicine, Nanjing University, Nanjing, PR China (M.Z.); and Beijing AnZhen Hospital, Affiliated to Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Diseases, The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Beijing, PR China (J.D.).
authors.forename: Xuan
authors.initials: X
authors.lastname: Cheng
authors.affiliation: From the State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Diseases, Institute of Biotechnology, Beijing, PR China (P.Z., S.H., J.C., J.Z., F.L., R.J., X.C., Y.L., X.Y.); Model Organism Division, E-institutes of Shanghai Universities, Shanghai Jiaotong University, Shanghai, PR China (P.Z., J.C., X.Y.); Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing, PR China (X.M., Y.S., Y.Z.); Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study and School of Medicine, Nanjing University, Nanjing, PR China (M.Z.); and Beijing AnZhen Hospital, Affiliated to Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Diseases, The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Beijing, PR China (J.D.).
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Ma
authors.affiliation: From the State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Diseases, Institute of Biotechnology, Beijing, PR China (P.Z., S.H., J.C., J.Z., F.L., R.J., X.C., Y.L., X.Y.); Model Organism Division, E-institutes of Shanghai Universities, Shanghai Jiaotong University, Shanghai, PR China (P.Z., J.C., X.Y.); Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing, PR China (X.M., Y.S., Y.Z.); Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study and School of Medicine, Nanjing University, Nanjing, PR China (M.Z.); and Beijing AnZhen Hospital, Affiliated to Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Diseases, The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Beijing, PR China (J.D.).
authors.forename: Yao
authors.initials: Y
authors.lastname: Song
authors.affiliation: From the State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Diseases, Institute of Biotechnology, Beijing, PR China (P.Z., S.H., J.C., J.Z., F.L., R.J., X.C., Y.L., X.Y.); Model Organism Division, E-institutes of Shanghai Universities, Shanghai Jiaotong University, Shanghai, PR China (P.Z., J.C., X.Y.); Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing, PR China (X.M., Y.S., Y.Z.); Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study and School of Medicine, Nanjing University, Nanjing, PR China (M.Z.); and Beijing AnZhen Hospital, Affiliated to Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Diseases, The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Beijing, PR China (J.D.).
authors.forename: Youyi
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: From the State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Diseases, Institute of Biotechnology, Beijing, PR China (P.Z., S.H., J.C., J.Z., F.L., R.J., X.C., Y.L., X.Y.); Model Organism Division, E-institutes of Shanghai Universities, Shanghai Jiaotong University, Shanghai, PR China (P.Z., J.C., X.Y.); Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing, PR China (X.M., Y.S., Y.Z.); Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study and School of Medicine, Nanjing University, Nanjing, PR China (M.Z.); and Beijing AnZhen Hospital, Affiliated to Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Diseases, The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Beijing, PR China (J.D.).
authors.forename: Minsheng
authors.initials: M
authors.lastname: Zhu
authors.affiliation: From the State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Diseases, Institute of Biotechnology, Beijing, PR China (P.Z., S.H., J.C., J.Z., F.L., R.J., X.C., Y.L., X.Y.); Model Organism Division, E-institutes of Shanghai Universities, Shanghai Jiaotong University, Shanghai, PR China (P.Z., J.C., X.Y.); Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing, PR China (X.M., Y.S., Y.Z.); Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study and School of Medicine, Nanjing University, Nanjing, PR China (M.Z.); and Beijing AnZhen Hospital, Affiliated to Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Diseases, The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Beijing, PR China (J.D.).
authors.forename: Jie
authors.initials: J
authors.lastname: Du
authors.affiliation: From the State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Diseases, Institute of Biotechnology, Beijing, PR China (P.Z., S.H., J.C., J.Z., F.L., R.J., X.C., Y.L., X.Y.); Model Organism Division, E-institutes of Shanghai Universities, Shanghai Jiaotong University, Shanghai, PR China (P.Z., J.C., X.Y.); Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing, PR China (X.M., Y.S., Y.Z.); Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study and School of Medicine, Nanjing University, Nanjing, PR China (M.Z.); and Beijing AnZhen Hospital, Affiliated to Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Diseases, The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Beijing, PR China (J.D.). rainyblue_1999@126.com yangx@bmi.ac.cn.
authors.forename: Yu
authors.initials: Y
authors.lastname: Lan
authors.affiliation: From the State Key Laboratory of Proteomics, Collaborative Innovation Center for Cardiovascular Disorders, Genetic Laboratory of Development and Diseases, Institute of Biotechnology, Beijing, PR China (P.Z., S.H., J.C., J.Z., F.L., R.J., X.C., Y.L., X.Y.); Model Organism Division, E-institutes of Shanghai Universities, Shanghai Jiaotong University, Shanghai, PR China (P.Z., J.C., X.Y.); Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Ministry of Health, Beijing, PR China (X.M., Y.S., Y.Z.); Model Animal Research Center and MOE Key Laboratory of Model Animal for Disease Study and School of Medicine, Nanjing University, Nanjing, PR China (M.Z.); and Beijing AnZhen Hospital, Affiliated to Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Diseases, The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Beijing, PR China (J.D.). rainyblue_1999@126.com yangx@bmi.ac.cn.
authors.forename: Xiao
authors.initials: X
authors.lastname: Yang
mesh_terms: D000818:Animals; D001011:Aorta / Q000378:metabolism / Q000473:pathology; D001014:Aortic Aneurysm / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000517:prevention & control; D002403:Cathepsins / Q000378:metabolism; D002460:Cell Line; D018925:Chemokines / Q000378:metabolism; D002633:Chemotaxis; D004549:Elastin / Q000378:metabolism; D005260:Female; D020022:Genetic Predisposition to Disease; D008264:Macrophages / Q000378:metabolism; D008297:Male; D053508:Matrix Metalloproteinase 12 / Q000378:metabolism; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009131:Muscle, Smooth, Vascular / Q000378:metabolism* / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism* / Q000473:pathology; D010641:Phenotype; D017346:Protein Serine-Threonine Kinases / Q000172:deficiency / Q000235:genetics; D059748:Proteolysis; D034622:RNA Interference; D051381:Rats; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000172:deficiency / Q000235:genetics; D051901:Smad4 Protein / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014162:Transfection; D015854:Up-Regulation
chemical_list: D018925:Chemokines; D018125:Receptors, Transforming Growth Factor beta; C497796:SMAD4 protein, human; D051901:Smad4 Protein; C490810:Smad4 protein, mouse; C490811:Smad4 protein, rat; D004549:Elastin; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II; D002403:Cathepsins; C028217:cathepsin S; D053508:Matrix Metalloproteinase 12; C000602031:matrix metallopeptidase 12, mouse
keywords: Smad4 protein; aortic aneurysm; aortic rupture; macrophages; myocytes, smooth muscle