title: Elevating CXCR7 Improves Angiogenic Function of EPCs via Akt/GSK-3β/Fyn-Mediated Nrf2 Activation in Diabetic Limb Ischemia.
abstract: BACKGROUND
  Endothelial progenitor cells (EPCs) respond to stromal cell-derived factor 1 (SDF-1) through chemokine receptors CXCR7 and CXCR4. Whether SDF-1 receptors involves in diabetes mellitus-induced EPCs dysfunction remains unknown.
  
  
  OBJECTIVE
  To determine the role of SDF-1 receptors in diabetic EPCs dysfunction.
  
  
  RESULTS
  CXCR7 expression, but not CXCR4 was reduced in EPCs fromdb/dbmice, which coincided with impaired tube formation. Knockdown of CXCR7 impaired tube formation of EPCs from normal mice, whereas upregulation of CXCR7 rescued angiogenic function of EPCs fromdb/dbmice. In normal EPCs treated with oxidized low-density lipoprotein or high glucose also reduced CXCR7 expression, impaired tube formation, and increased oxidative stress and apoptosis. The damaging effects of oxidized low-density lipoprotein or high glucose were markedly reduced by SDF-1 pretreatment in EPCs transduced with CXCR7 lentivirus but not in EPCs transduced with control lentivirus. Most importantly, EPCs transduced with CXCR7 lentivirus were superior to EPCs transduced with control lentivirus for therapy of ischemic limbs indb/dbmice. Mechanistic studies demonstrated that oxidized low-density lipoprotein or high glucose inhibited protein kinase B and glycogen synthase kinase-3β phosphorylation, nuclear export of Fyn and nuclear localization of nuclear factor (erythroid-derived 2)-like 2 (Nrf2), blunting Nrf2 downstream target genes heme oxygenase-1, NAD(P)H dehydrogenase (quinone 1) and catalase, and inducing an increase in EPC oxidative stress. This destructive cascade was blocked by SDF-1 treatment in EPCs transduced with CXCR7 lentivirus. Furthermore, inhibition of phosphatidylinositol 3-kinase/protein kinase B prevented SDF-1/CXCR7-mediated Nrf2 activation and blocked angiogenic repair. Moreover, Nrf2 knockdown almost completely abolished the protective effects of SDF-1/CXCR7 on EPC function in vitro and in vivo.
  
  
  CONCLUSIONS
  Elevated expression of CXCR7 enhances EPC resistance to diabetes mellitus-induced oxidative damage and improves therapeutic efficacy of EPCs in treating diabetic limb ischemia. The benefits of CXCR7 are mediated predominantly by a protein kinase B/glycogen synthase kinase-3β/Fyn pathway via increased activity of Nrf2.
authors.affiliation: From the Chinese-American Research Institute for Diabetic Complications, School of Pharmaceutical Sciences & School of Nursing at the Wenzhou Medical University, Wenzhou, China (X.D., X.Y., Jun Chen, X.L., Y.T.); School of Biomedicine, Chengdu Medical College, China (X.D., K.P.); Department of Pediatrics, Children's Hospital Research Institute, School of Medicine (X.D., J.Z., Jing Chen, Jun Chen, P.N.E., Y.T.), Department of Surgery (Y.L.), Department of Medicine (M.T.B., M.A.N., D.J.C.), Division of Endocrinology, Department of Pediatrics, Wendy L. Novak Diabetes Care Center (K.A.W.), and Diabetes and Obesity Center (D.J.C.), University of Louisville, KY; Departments of Geriatrics, the First Hospital of Jilin University, Changchun, China (Y.W.); and Division of Cardiovascular Disease, University of Alabama at Birmingham (G.R.).
authors.forename: Xiaozhen
authors.initials: X
authors.lastname: Dai
authors.affiliation: From the Chinese-American Research Institute for Diabetic Complications, School of Pharmaceutical Sciences & School of Nursing at the Wenzhou Medical University, Wenzhou, China (X.D., X.Y., Jun Chen, X.L., Y.T.); School of Biomedicine, Chengdu Medical College, China (X.D., K.P.); Department of Pediatrics, Children's Hospital Research Institute, School of Medicine (X.D., J.Z., Jing Chen, Jun Chen, P.N.E., Y.T.), Department of Surgery (Y.L.), Department of Medicine (M.T.B., M.A.N., D.J.C.), Division of Endocrinology, Department of Pediatrics, Wendy L. Novak Diabetes Care Center (K.A.W.), and Diabetes and Obesity Center (D.J.C.), University of Louisville, KY; Departments of Geriatrics, the First Hospital of Jilin University, Changchun, China (Y.W.); and Division of Cardiovascular Disease, University of Alabama at Birmingham (G.R.).
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Yan
authors.affiliation: From the Chinese-American Research Institute for Diabetic Complications, School of Pharmaceutical Sciences & School of Nursing at the Wenzhou Medical University, Wenzhou, China (X.D., X.Y., Jun Chen, X.L., Y.T.); School of Biomedicine, Chengdu Medical College, China (X.D., K.P.); Department of Pediatrics, Children's Hospital Research Institute, School of Medicine (X.D., J.Z., Jing Chen, Jun Chen, P.N.E., Y.T.), Department of Surgery (Y.L.), Department of Medicine (M.T.B., M.A.N., D.J.C.), Division of Endocrinology, Department of Pediatrics, Wendy L. Novak Diabetes Care Center (K.A.W.), and Diabetes and Obesity Center (D.J.C.), University of Louisville, KY; Departments of Geriatrics, the First Hospital of Jilin University, Changchun, China (Y.W.); and Division of Cardiovascular Disease, University of Alabama at Birmingham (G.R.).
authors.forename: Jun
authors.initials: J
authors.lastname: Zeng
authors.affiliation: From the Chinese-American Research Institute for Diabetic Complications, School of Pharmaceutical Sciences & School of Nursing at the Wenzhou Medical University, Wenzhou, China (X.D., X.Y., Jun Chen, X.L., Y.T.); School of Biomedicine, Chengdu Medical College, China (X.D., K.P.); Department of Pediatrics, Children's Hospital Research Institute, School of Medicine (X.D., J.Z., Jing Chen, Jun Chen, P.N.E., Y.T.), Department of Surgery (Y.L.), Department of Medicine (M.T.B., M.A.N., D.J.C.), Division of Endocrinology, Department of Pediatrics, Wendy L. Novak Diabetes Care Center (K.A.W.), and Diabetes and Obesity Center (D.J.C.), University of Louisville, KY; Departments of Geriatrics, the First Hospital of Jilin University, Changchun, China (Y.W.); and Division of Cardiovascular Disease, University of Alabama at Birmingham (G.R.).
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.affiliation: From the Chinese-American Research Institute for Diabetic Complications, School of Pharmaceutical Sciences & School of Nursing at the Wenzhou Medical University, Wenzhou, China (X.D., X.Y., Jun Chen, X.L., Y.T.); School of Biomedicine, Chengdu Medical College, China (X.D., K.P.); Department of Pediatrics, Children's Hospital Research Institute, School of Medicine (X.D., J.Z., Jing Chen, Jun Chen, P.N.E., Y.T.), Department of Surgery (Y.L.), Department of Medicine (M.T.B., M.A.N., D.J.C.), Division of Endocrinology, Department of Pediatrics, Wendy L. Novak Diabetes Care Center (K.A.W.), and Diabetes and Obesity Center (D.J.C.), University of Louisville, KY; Departments of Geriatrics, the First Hospital of Jilin University, Changchun, China (Y.W.); and Division of Cardiovascular Disease, University of Alabama at Birmingham (G.R.).
authors.forename: Yuehui
authors.initials: Y
authors.lastname: Wang
authors.affiliation: From the Chinese-American Research Institute for Diabetic Complications, School of Pharmaceutical Sciences & School of Nursing at the Wenzhou Medical University, Wenzhou, China (X.D., X.Y., Jun Chen, X.L., Y.T.); School of Biomedicine, Chengdu Medical College, China (X.D., K.P.); Department of Pediatrics, Children's Hospital Research Institute, School of Medicine (X.D., J.Z., Jing Chen, Jun Chen, P.N.E., Y.T.), Department of Surgery (Y.L.), Department of Medicine (M.T.B., M.A.N., D.J.C.), Division of Endocrinology, Department of Pediatrics, Wendy L. Novak Diabetes Care Center (K.A.W.), and Diabetes and Obesity Center (D.J.C.), University of Louisville, KY; Departments of Geriatrics, the First Hospital of Jilin University, Changchun, China (Y.W.); and Division of Cardiovascular Disease, University of Alabama at Birmingham (G.R.).
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.affiliation: From the Chinese-American Research Institute for Diabetic Complications, School of Pharmaceutical Sciences & School of Nursing at the Wenzhou Medical University, Wenzhou, China (X.D., X.Y., Jun Chen, X.L., Y.T.); School of Biomedicine, Chengdu Medical College, China (X.D., K.P.); Department of Pediatrics, Children's Hospital Research Institute, School of Medicine (X.D., J.Z., Jing Chen, Jun Chen, P.N.E., Y.T.), Department of Surgery (Y.L.), Department of Medicine (M.T.B., M.A.N., D.J.C.), Division of Endocrinology, Department of Pediatrics, Wendy L. Novak Diabetes Care Center (K.A.W.), and Diabetes and Obesity Center (D.J.C.), University of Louisville, KY; Departments of Geriatrics, the First Hospital of Jilin University, Changchun, China (Y.W.); and Division of Cardiovascular Disease, University of Alabama at Birmingham (G.R.).
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: From the Chinese-American Research Institute for Diabetic Complications, School of Pharmaceutical Sciences & School of Nursing at the Wenzhou Medical University, Wenzhou, China (X.D., X.Y., Jun Chen, X.L., Y.T.); School of Biomedicine, Chengdu Medical College, China (X.D., K.P.); Department of Pediatrics, Children's Hospital Research Institute, School of Medicine (X.D., J.Z., Jing Chen, Jun Chen, P.N.E., Y.T.), Department of Surgery (Y.L.), Department of Medicine (M.T.B., M.A.N., D.J.C.), Division of Endocrinology, Department of Pediatrics, Wendy L. Novak Diabetes Care Center (K.A.W.), and Diabetes and Obesity Center (D.J.C.), University of Louisville, KY; Departments of Geriatrics, the First Hospital of Jilin University, Changchun, China (Y.W.); and Division of Cardiovascular Disease, University of Alabama at Birmingham (G.R.).
authors.forename: Michelle T
authors.initials: MT
authors.lastname: Barati
authors.affiliation: From the Chinese-American Research Institute for Diabetic Complications, School of Pharmaceutical Sciences & School of Nursing at the Wenzhou Medical University, Wenzhou, China (X.D., X.Y., Jun Chen, X.L., Y.T.); School of Biomedicine, Chengdu Medical College, China (X.D., K.P.); Department of Pediatrics, Children's Hospital Research Institute, School of Medicine (X.D., J.Z., Jing Chen, Jun Chen, P.N.E., Y.T.), Department of Surgery (Y.L.), Department of Medicine (M.T.B., M.A.N., D.J.C.), Division of Endocrinology, Department of Pediatrics, Wendy L. Novak Diabetes Care Center (K.A.W.), and Diabetes and Obesity Center (D.J.C.), University of Louisville, KY; Departments of Geriatrics, the First Hospital of Jilin University, Changchun, China (Y.W.); and Division of Cardiovascular Disease, University of Alabama at Birmingham (G.R.).
authors.forename: Kupper A
authors.initials: KA
authors.lastname: Wintergerst
authors.affiliation: From the Chinese-American Research Institute for Diabetic Complications, School of Pharmaceutical Sciences & School of Nursing at the Wenzhou Medical University, Wenzhou, China (X.D., X.Y., Jun Chen, X.L., Y.T.); School of Biomedicine, Chengdu Medical College, China (X.D., K.P.); Department of Pediatrics, Children's Hospital Research Institute, School of Medicine (X.D., J.Z., Jing Chen, Jun Chen, P.N.E., Y.T.), Department of Surgery (Y.L.), Department of Medicine (M.T.B., M.A.N., D.J.C.), Division of Endocrinology, Department of Pediatrics, Wendy L. Novak Diabetes Care Center (K.A.W.), and Diabetes and Obesity Center (D.J.C.), University of Louisville, KY; Departments of Geriatrics, the First Hospital of Jilin University, Changchun, China (Y.W.); and Division of Cardiovascular Disease, University of Alabama at Birmingham (G.R.).
authors.forename: Kejian
authors.initials: K
authors.lastname: Pan
authors.affiliation: From the Chinese-American Research Institute for Diabetic Complications, School of Pharmaceutical Sciences & School of Nursing at the Wenzhou Medical University, Wenzhou, China (X.D., X.Y., Jun Chen, X.L., Y.T.); School of Biomedicine, Chengdu Medical College, China (X.D., K.P.); Department of Pediatrics, Children's Hospital Research Institute, School of Medicine (X.D., J.Z., Jing Chen, Jun Chen, P.N.E., Y.T.), Department of Surgery (Y.L.), Department of Medicine (M.T.B., M.A.N., D.J.C.), Division of Endocrinology, Department of Pediatrics, Wendy L. Novak Diabetes Care Center (K.A.W.), and Diabetes and Obesity Center (D.J.C.), University of Louisville, KY; Departments of Geriatrics, the First Hospital of Jilin University, Changchun, China (Y.W.); and Division of Cardiovascular Disease, University of Alabama at Birmingham (G.R.).
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Nystoriak
authors.affiliation: From the Chinese-American Research Institute for Diabetic Complications, School of Pharmaceutical Sciences & School of Nursing at the Wenzhou Medical University, Wenzhou, China (X.D., X.Y., Jun Chen, X.L., Y.T.); School of Biomedicine, Chengdu Medical College, China (X.D., K.P.); Department of Pediatrics, Children's Hospital Research Institute, School of Medicine (X.D., J.Z., Jing Chen, Jun Chen, P.N.E., Y.T.), Department of Surgery (Y.L.), Department of Medicine (M.T.B., M.A.N., D.J.C.), Division of Endocrinology, Department of Pediatrics, Wendy L. Novak Diabetes Care Center (K.A.W.), and Diabetes and Obesity Center (D.J.C.), University of Louisville, KY; Departments of Geriatrics, the First Hospital of Jilin University, Changchun, China (Y.W.); and Division of Cardiovascular Disease, University of Alabama at Birmingham (G.R.).
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Conklin
authors.affiliation: From the Chinese-American Research Institute for Diabetic Complications, School of Pharmaceutical Sciences & School of Nursing at the Wenzhou Medical University, Wenzhou, China (X.D., X.Y., Jun Chen, X.L., Y.T.); School of Biomedicine, Chengdu Medical College, China (X.D., K.P.); Department of Pediatrics, Children's Hospital Research Institute, School of Medicine (X.D., J.Z., Jing Chen, Jun Chen, P.N.E., Y.T.), Department of Surgery (Y.L.), Department of Medicine (M.T.B., M.A.N., D.J.C.), Division of Endocrinology, Department of Pediatrics, Wendy L. Novak Diabetes Care Center (K.A.W.), and Diabetes and Obesity Center (D.J.C.), University of Louisville, KY; Departments of Geriatrics, the First Hospital of Jilin University, Changchun, China (Y.W.); and Division of Cardiovascular Disease, University of Alabama at Birmingham (G.R.).
authors.forename: Gregg
authors.initials: G
authors.lastname: Rokosh
authors.affiliation: From the Chinese-American Research Institute for Diabetic Complications, School of Pharmaceutical Sciences & School of Nursing at the Wenzhou Medical University, Wenzhou, China (X.D., X.Y., Jun Chen, X.L., Y.T.); School of Biomedicine, Chengdu Medical College, China (X.D., K.P.); Department of Pediatrics, Children's Hospital Research Institute, School of Medicine (X.D., J.Z., Jing Chen, Jun Chen, P.N.E., Y.T.), Department of Surgery (Y.L.), Department of Medicine (M.T.B., M.A.N., D.J.C.), Division of Endocrinology, Department of Pediatrics, Wendy L. Novak Diabetes Care Center (K.A.W.), and Diabetes and Obesity Center (D.J.C.), University of Louisville, KY; Departments of Geriatrics, the First Hospital of Jilin University, Changchun, China (Y.W.); and Division of Cardiovascular Disease, University of Alabama at Birmingham (G.R.).
authors.forename: Paul N
authors.initials: PN
authors.lastname: Epstein
authors.affiliation: From the Chinese-American Research Institute for Diabetic Complications, School of Pharmaceutical Sciences & School of Nursing at the Wenzhou Medical University, Wenzhou, China (X.D., X.Y., Jun Chen, X.L., Y.T.); School of Biomedicine, Chengdu Medical College, China (X.D., K.P.); Department of Pediatrics, Children's Hospital Research Institute, School of Medicine (X.D., J.Z., Jing Chen, Jun Chen, P.N.E., Y.T.), Department of Surgery (Y.L.), Department of Medicine (M.T.B., M.A.N., D.J.C.), Division of Endocrinology, Department of Pediatrics, Wendy L. Novak Diabetes Care Center (K.A.W.), and Diabetes and Obesity Center (D.J.C.), University of Louisville, KY; Departments of Geriatrics, the First Hospital of Jilin University, Changchun, China (Y.W.); and Division of Cardiovascular Disease, University of Alabama at Birmingham (G.R.).
authors.forename: Xiaokun
authors.initials: X
authors.lastname: Li
authors.affiliation: From the Chinese-American Research Institute for Diabetic Complications, School of Pharmaceutical Sciences & School of Nursing at the Wenzhou Medical University, Wenzhou, China (X.D., X.Y., Jun Chen, X.L., Y.T.); School of Biomedicine, Chengdu Medical College, China (X.D., K.P.); Department of Pediatrics, Children's Hospital Research Institute, School of Medicine (X.D., J.Z., Jing Chen, Jun Chen, P.N.E., Y.T.), Department of Surgery (Y.L.), Department of Medicine (M.T.B., M.A.N., D.J.C.), Division of Endocrinology, Department of Pediatrics, Wendy L. Novak Diabetes Care Center (K.A.W.), and Diabetes and Obesity Center (D.J.C.), University of Louisville, KY; Departments of Geriatrics, the First Hospital of Jilin University, Changchun, China (Y.W.); and Division of Cardiovascular Disease, University of Alabama at Birmingham (G.R.). yi.tan@louisville.edu.
authors.forename: Yi
authors.initials: Y
authors.lastname: Tan
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003920:Diabetes Mellitus / Q000378:metabolism* / Q000473:pathology; D066026:Endothelial Progenitor Cells / Q000502:physiology*; D055785:Gene Knockdown Techniques; D000071679:Glycogen Synthase Kinase 3 beta / Q000378:metabolism*; D057809:HEK293 Cells; D006614:Hindlimb / Q000098:blood supply / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007511:Ischemia / Q000378:metabolism* / Q000473:pathology; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000502:physiology; D018384:Oxidative Stress / Q000502:physiology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051076:Proto-Oncogene Proteins c-fyn / Q000378:metabolism*; D054387:Receptors, CXCR / Q000096:biosynthesis*
chemical_list: C501897:Cmkor1 protein, mouse; D051267:NF-E2-Related Factor 2; C495636:Nfe2l2 protein, mouse; D054387:Receptors, CXCR; C494960:Fyn protein, mouse; D051076:Proto-Oncogene Proteins c-fyn; D000071679:Glycogen Synthase Kinase 3 beta; D051057:Proto-Oncogene Proteins c-akt
keywords: CXC chemokine receptor type 7; angiogenesis; chemokine CXCL12; endothelial progenitor cells; hindlimb ischemia