The Effects Of Celladhension Molecule CD146 Promotes Choroidal Neovascularization In Wet Age-related Macular Degeneration

Background: With the increase of life expectancy and society ages,the incidence of age-related macular degeneration(AMD)has increased significantly in our country.According to the clinical guideline of the 2016 ophthalmology,AMD can be divided into dry AMD and wet AMD.Dry AMD is characterized by a large number of drusen subretinal deposition in the macular area.Wet AMD is characterized by the formation of choroidal neovascularization(CNV).exudative of CNV are the main causes of irreversible of visual impairment.Cell adhesion molecule CD146(also known as MUC18?MCAM)is a transmembrane protein belongs to the immunoglobulin superfamily.CD146 has an extracellular fragment of V-V-C2-C2-C2 with five classic immunoglobulin-like domains and intracellular fragment contains protein kinase C(PKC)and ERM protein kinase binding sites.CD146 as a cell adhesion mole participate in cell-cell and cell-matrix adhesion process,not only act as a “molecular glue”,but also regulates the permeability of cells,promotes angiogenesis and transmembrane signaling.CD146 was found and isolated from melanoma cells firstly.Many papers reported that CD146 was highly expressed in melanoma,breast cancer,colon cancer and so on.It can regulate the initiation of neovascularization,proliferation and migration of endothelial cells.Anti-CD146 antibody can inhibit the neovascularization and growth of tumors.YAN has reported that CD146 is expressed in human eyes and take part in the formation of retinacular,but there is no evidence shown whether CD146 is involved in the process of CNV.Based on the current research background,the following three aspects will be carried out in this research:(1)How about the expression level of sCD146 and VEGFR2 in serum of patients with wet age-related macular degeneration?(2)Whether CD146 is participated in the development of CNV in the models by polyethylene glycol(PEG)subretinal injection?(3)The possible molecular mechanism of CD146 and VEGFR2 in the formation of CNV.We aim to provide new evidence for discovering new therapeutic targets to protect against wet AMD through out the three aspects of investigations.Purpose: The aim of this investigation is to explore the expression and significance of CD146 in circulation levels of patients with wet AMD and to investigate the role and possible molecular mechanism of CD146 and VEGFR2 in the formation of CNV in mice.Methods: Eighty-eight patients with exudative AMD and 45 healthy controls were enrolled in this study conducted in the Department ofOphthalmology,the First Affiliated Hospital of Chongqing Medical University.All of the venous blood obtained from the patients with exudative AMD and the controls were centrifugated and the serum samples were collected in 4 hours.Serum sCD146 and VEGFR2 protein levels were measured using an enzyme-linked immunosorbent assay.sixty C57BL/6J male mice aged 8 weeks were divided into post trans-corneally subretinal injection 5 days group,10 days group and 15 days group randomly based on the sampling times,with twenty mice in each grouping.phosphate buffer saline(PBS)subretinal injection was performed on the left eyes of mice were set as normal control and the right eyes were established CNV models by polyethylene glycol(PEG)subretinal injection.Hematoxylin-eosin staining(HE)were use to identify the CNV model.The mRNA levels of CD146 and vascular endothelial growth factor(VEGF)and vascular endothelial growth factor receptor 2(VEGFR2)in neuroretina and RPE/choroid complex were detected by real-time PCR at the 5th,10 th and 15 th day post subretinal injection respectively.Immunohistochemical staining was used to detected the expression of CD146,VEGF and VEGFR2 in the eyes of mice after injection.Results: Compared with normal participates,the expression of sCD146 and VEGFR2 in serum of patients with wet AMD was significantly increased,and the results were statistically different.The mRNA expression of VEGF in neuroretina was significantly higher in theexperiment group than in the control group at 5 days after subretinal injection.The mRNA expression of CD146,VEGF,and VEGFR2 in neuroretina and choroid was significantly higher in the experiment group than in the control group at 5 and of 10 days after subretinal injection.The person correlation analysis showed that the expression of CD146 was positively correlated with VEGF in neuroretina and in choroid tissue,and positively correlated with VEGFR2 in choroid tissue.Meanwhile the result of immunohistochemical staining showed that the positive areas of CD146,VEGF,VEGFR2 in post injected 10 days group included ganglion cell layer,inner nuclear layered,outer nuclear layer.Conclusions: The high expression level of CD146 correlates with VEGF positively in serum,suggesting that CD146 is closely related to the pathogenesis and development of wet AMD.The coherent high expression of CD146,VEGF,VEGFR2 in CNV model indicate the potent synergistic reactions among themselves.Although the specific mechanism is unknown,but this results can help us to recognize the mechanism of wet AMD and provide a novel diagnostic and more safe and effective therapeutic strategy for wet AMD.