title: Slit2 Promotes Angiogenic Activity Via the Robo1-VEGFR2-ERK1/2 Pathway in Both In Vivo and In Vitro Studies.
abstract: OBJECTIVE
  Recent research has provided novel but contrary insight into the function of Slit2-Robo signaling in angiogenesis. Although the role of Robo in choroidal neovascularization (CNV) has been studied, the effect of its ligand, Slit2, on CNV development is unclear. This study investigated the role of endogenous Slit2 in CNV and the possible mechanisms.
  
  
  METHODS
  Laser-induced CNV in Slit2 transgenic and wild-type mice was used to study the effects of endogenous Slit2 on angiogenesis in vivo. Fluorescein angiography was performed to evaluate the leakage area of each lesion. Plasmid-based gene transfer technology was used to increase Slit2 expression and to study its effects on human umbilical vein endothelial cells (HUVECs) in vitro. Cell proliferation, migration, and tube formation were assessed. Quantitative real-time PCR and Western blot were used to measure expression in the extracellular signal-related kinase 1/2 (ERK1/2), protein kinase B (AKT), and p38 mitogen-activated protein kinase (p38 MAPK) molecular pathways.
  
  
  RESULTS
  Laser treatment led to more CNV and vascular leakage in Slit2 transgenic mice compared with wild-type mice. Upregulation of Slit2, Robo1, VEGF receptor 2 (VEGFR2), and phosphorylated ERK1/2 (p-ERK1/2) were detected in retina and choroidal tissue of laser-treated transgenic mice. After transfection of HUVECs with a Slit2 overexpression plasmid, cell proliferation, migration, and tube formation capacities were promoted. Slit2, Robo1, VEGFR2, and p-ERK1/2 were elevated in transfected HUVECs.
  
  
  CONCLUSIONS
  Slit2 overexpression promoted angiogenic effects in both a laser-induced CNV mouse model and HUVECs and promoted the biological activity of endothelial cells. Slit2 may promote angiogenesis by upregulating Robo1 and activating the VEGFR2-ERK1/2 pathway.
authors.affiliation: Department of Ophthalmology Peking University People's Hospital; Key Laboratory of Vision Loss and Restoration, Ministry of Education; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Ophthalmology Peking University People's Hospital; Key Laboratory of Vision Loss and Restoration, Ministry of Education; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China.
authors.forename: Lvzhen
authors.initials: L
authors.lastname: Huang
authors.affiliation: Department of Ophthalmology Peking University People's Hospital; Key Laboratory of Vision Loss and Restoration, Ministry of Education; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China.
authors.forename: Yaoyao
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Ophthalmology Peking University People's Hospital; Key Laboratory of Vision Loss and Restoration, Ministry of Education; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China.
authors.forename: Yujing
authors.initials: Y
authors.lastname: Bai
authors.affiliation: Department of Ophthalmology Peking University People's Hospital; Key Laboratory of Vision Loss and Restoration, Ministry of Education; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Yang
authors.affiliation: Department of Ophthalmology Peking University People's Hospital; Key Laboratory of Vision Loss and Restoration, Ministry of Education; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China.
authors.forename: Wenzhen
authors.initials: W
authors.lastname: Yu
authors.affiliation: Department of Ophthalmology Peking University People's Hospital; Key Laboratory of Vision Loss and Restoration, Ministry of Education; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China.
authors.forename: Fangting
authors.initials: F
authors.lastname: Li
authors.affiliation: Department of Ophthalmology Peking University People's Hospital; Key Laboratory of Vision Loss and Restoration, Ministry of Education; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Ophthalmology Peking University People's Hospital; Key Laboratory of Vision Loss and Restoration, Ministry of Education; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.affiliation: Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan, United States.
authors.forename: Jian-Guo
authors.initials: JG
authors.lastname: Geng
authors.affiliation: Department of Ophthalmology Peking University People's Hospital; Key Laboratory of Vision Loss and Restoration, Ministry of Education; Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China.
authors.forename: Xiaoxin
authors.initials: X
authors.lastname: Li
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002465:Cell Movement; D049109:Cell Proliferation; D002478:Cells, Cultured; D020256:Choroidal Neovascularization / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D029721:Drosophila Proteins; D005260:Female; D005451:Fluorescein Angiography; D005654:Fundus Oculi; D005786:Gene Expression Regulation; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D006801:Humans; D066298:In Vitro Techniques; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis / Q000235:genetics*; D020935:MAP Kinase Signaling System / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics*; D012313:RNA / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D011971:Receptors, Immunologic / Q000096:biosynthesis / Q000235:genetics*; D015398:Signal Transduction / Q000187:drug effects; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000096:biosynthesis / Q000235:genetics*; D000097905:Roundabout Proteins; D000098552:Slit Homolog 2 Protein
chemical_list: D029721:Drosophila Proteins; D036341:Intercellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D012313:RNA; D011971:Receptors, Immunologic; D040301:Vascular Endothelial Growth Factor Receptor-2; D000097905:Roundabout Proteins; D000098552:Slit Homolog 2 Protein