The Role Of Reticulon 4B In Angiogenesis Of Diabetic Retinopathy

Objective: This study explored the role of Nogo-B in the angiogenesis in proliferative diabetic retinopathy(PDR)patients and primary human retinal endothelial cells(HRMECs).Methods: Vitreous fluids and fibrovascular tissures were collected from PDR patients who had undergone vitrectomy.And non-diabetic macular hole and rhegmatogenous retinal detachment patients were served as control groups.The expression of Nogo-B in fibrovascular tissures and vitreous humor were detected by immunohistochemistry and ELISA assay.NogoB was down-regulated through the use of lentivirus-NogoB-RNAi,the effects of Nogo-B on angiogenesis under high glucose stimulation were evaluated via CCK-8 assay,wound closure assay,transwell assay,and tube formation assay.Expression of soluble Nogo-B,PI3 K and Akt were determined by western blotting,immunofluorescence and ELISA assay.Co-culture systerm was used to explore cell-cell communication.Soluble Nogo-B was constructed and applied to stimulate HRMECs.Mice model of oxygen-induced retinopathy(OIR)was used to verify the function of Nogo-B in retinal angiogenesis.Results: Nogo-B was highly enriched in vitreous fluids of PDR patients and in HRMECs exposed to high glucose.Besides,Nogo-B signal was colocalized with the signal of CD31 in fibrovascular tissures of PDR patients by immunofluorescence assay.Down-regulation of Nogo-B attenuated high glucose induced cell migration and tube formation in HRMECs.Mechanistically,in comparison with the negative control group,lentivirus-NogoB-RNAi group had exhibited weakened PI3 K and Akt activation.Futher,high glucose treatment promoted the secretion of soluble Nogo-B and presented as a “long-term memory”.Soluble Nogo-B stimulation also enhanced HRMECs' function of cell migration and tube formation.Finally,intravitreous injection of sNogo-B increased retinal neovascular formation in OIR mice model.Conclusions: These data collectively indicated that expression of Nogo-B was increased in PDR patients,and Nogo-B promoted angiogenesis in HRMECs via PI3K/Akt pathway in an autocrine manner.