title: Down-regulation of microRNA-155 attenuates retinal neovascularization via the PI3K/Akt pathway.
abstract: OBJECTIVE
  We aimed to investigate the anti-angiogenic properties of miR-155 via in vitro and in vivo studies.
  
  
  METHODS
  miR-155 was knocked down using lentivirus-mediated RNA interference. The proliferation, migration, and tube formation of human retinal microvascular endothelial cells (HRMECs) were measured using BrdU, Transwell, and Matrigel assays, respectively. An oxygen-induced retinopathy (OIR) model was induced using neonatal C57BL/6J pups. Anti-miR-155 was intravitreally injected on postnatal day 12, and the retinal non-perfused areas and extent of neovascularization were measured on postnatal day 18 using transcardiovascular fluorescein isothiocyanate (FITC)-dextran perfusion and retina sections. A laser-induced choroidal neovascularization (CNV) model was induced in adult C57BL/6J mice. To evaluate the leakage areas, fundus fluorescein angiography was performed on day 14 after anti-miR-155 intravitreal injection. The neovascularization area of the CNV model was also examined in confocal and retina section studies. The expression levels of SHIP1 and p-Akt (Thr308, Ser473, and Thr450) were evaluated both in vitro and in vivo.
  
  
  RESULTS
  The expression of miR-155 was elevated in HRMECs after treatment with vascular endothelial growth factor (VEGF) and in neovascularized mouse model retinas. Anti-miR-155 lentivirus reduced the VEGF-induced proliferation, migration, and tube formation abilities of HRMECs. Anti-miR-155 attenuated retinal neovascularization in in vivo CNV and OIR models. In VEGF-treated HRMECs and retina neovascularization models, p-Akt (Ser473) was significantly upregulated, while SHIP1 was downregulated. Conversely, the inhibition of miR-155 restored the expression of SHIP1 and reduced the phosphorylation of effectors in the Akt (Ser473) signaling pathway.
  
  
  CONCLUSIONS
  The results revealed that the downregulation of miR-155 attenuated retinal neovascularization via the phosphatidylinositol 3-kinase (PI3K)/Akt pathway.
authors.affiliation: Medical College, Inner Mongolia University for the Nationalities, Tongliao Inner Mongolia, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Zhuang
authors.affiliation: Department of Ophthalmology, Affiliated Hospital of Inner Mongolia University for the Nationalities, Tongliao Inner Mongolia, China.
authors.lastname: Xiao-qin
authors.affiliation: Medical College, Inner Mongolia University for the Nationalities, Tongliao Inner Mongolia, China.
authors.forename: He
authors.initials: H
authors.lastname: Hu
authors.affiliation: Department of Ophthalmology, Affiliated Hospital of Inner Mongolia University for the Nationalities, Tongliao Inner Mongolia, China.
authors.forename: Shi-yuan
authors.initials: SY
authors.lastname: Tian
authors.affiliation: Department of Ophthalmology, Affiliated Hospital of Inner Mongolia University for the Nationalities, Tongliao Inner Mongolia, China.
authors.forename: Zhan-jun
authors.initials: ZJ
authors.lastname: Lu
authors.affiliation: Department of Ophthalmology, Affiliated Hospital of Inner Mongolia University for the Nationalities, Tongliao Inner Mongolia, China.
authors.forename: Tian-zi
authors.initials: TZ
authors.lastname: Zhang
authors.affiliation: Department of Ophthalmology, Affiliated Hospital of Inner Mongolia University for the Nationalities, Tongliao Inner Mongolia, China.
authors.forename: Yu-ling
authors.initials: YL
authors.lastname: Bai
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002465:Cell Movement; D049109:Cell Proliferation; D020256:Choroidal Neovascularization / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D042783:Endothelial Cells / Q000378:metabolism* / Q000473:pathology; D005451:Fluorescein Angiography; D005786:Gene Expression Regulation; D005822:Genetic Vectors; D006801:Humans; D000072181:Inositol Polyphosphate 5-Phosphatases; D058449:Intravitreal Injections; D016086:Lentivirus / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D009841:Oligonucleotides / Q000235:genetics / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics* / Q000378:metabolism; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D061251:Primary Cell Culture; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics* / Q000378:metabolism; D012160:Retina / Q000378:metabolism / Q000473:pathology; D015398:Signal Transduction; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism
chemical_list: C524942:MIRN155 microRNA, human; D035683:MicroRNAs; D009841:Oligonucleotides; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D010744:Phosphoric Monoester Hydrolases; D000072181:Inositol Polyphosphate 5-Phosphatases; C000606430:INPP5D protein, human; C000606433:Inpp5d protein, mouse; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases