RESUMEN
Objective:To predict the transmembrane structure of transmembrane protein 26 (TMEM26), observe its expression in human retina and mouse retina, and investigate the relationship between it and primary open-angle glaucoma (POAG).Methods:The transmembrane structure of TMEM26 in human and mouse was obtained by inputting its amino acid sequences into the transmembrane protein structure prediction software, MemBrain.The expression and location of TMEM26 in human and mouse retinas were observed through frozen retinal sections stained with anti-TMEM26 antibody, which came from a human donor and five SPF-grade C57BL/6 mice.The possible function of TMEM26 gene and its influence on eyes were inferred on the basis of the specific expression of TMEM26 in retina.The single nucleotide polymorphism mutation of TMEM26 gene was searched in literature related to ocular diseases.The use and care of animals complied with the Regulations on the Management of Experimental Animals.This research protocol was approved by an Ethics Committee of Sichuan Provincial People's Hospital (No.2019-36). Results:Both human and mouse TMEM26 were eight transmembrane proteins with similar eight hydrophobic transmembrane domains, four hydrophilic cytoplasmic domains and five hydrophilic extracellular membrane domains.Small differences in the number of amino acid residues in the domains of TMEM26 were found.In both human and mouse retina, TMEM26 gene was only specifically expressed in the outer plexiform layer (OPL)and inner plexiform layer (IPL). TMEM26 was weakly associated with POAG in a published data. Conclusions:TMEM26 is a multi-pass transmembrane protein, mainly expressed in IPL and OPL of the retina. TMEM26 gene is weakly related to POAG.
RESUMEN
Background Retinal angiomatous proliferation (RAP) is a subtype of neovascular age-related macular degeneration (AMD).There are currently very few studies on RAP.Objective This study was to explore the pathogenic mechanism of RAP in apolipoprotein E-deficient (ApoE-/-) mice with dyslipidemia.Methods Twenty-four 2-month-old SPF ApoE-/-mice were randomly divided into the high fat diet group and the normal diet group,and twelve 2-month-old C57BL/6 mice received the normal diet as controls.A diet with a higher content of fat was given for 4 consecutive months in the high fat diet group,and normal diet was given in the same way in the mice of the normal diet group.The mice were sacrificed at 6 months of age.The expression of vascular endothelial growth factor (VEGF) in the retinal pigment epithelial (RPE) cells,the expression of vascular endothelial growth factor receptor-2 (VEGFR-2) in the outer plexiform layer (OPL),microvascular density (MVD) and microvascular area (MVA) in the OPL were examined by immunohistochemistry and semi-quantitatively by histopathology with the Mias 2000 Imaging Analyzer System.The expression of VEGF protein in the retina was examined by Western blot.Results The MVD in the retinal OPL were (20.67±3.20) and (19.50± 1.87),respectively,in the ApoE-/-mice of the high fat diet group and the normal diet group,which were significantly higher than that (12.50±1.87) of the C57BL/6 normal diet group (all at P＜0.01).MVA in the retinal OPL were (626.49± 120.99) μm2 and (514.06±88.83) μm2 in the ApoE-/-mice of the high fat diet group and the normal diet group,respectively,showing a significant increase in comparison with the (336.52±84.96) μm2 of the C57BL/6 normal diet group (P＜0.01).The staining area of VEGF in RPE cells was (21 048±1849) μm2 in the ApoE-/-mice of the high fat diet group,showing a significant increase in comparison with the (17 116±2023) μm2 of the C57BL/6 normal diet group.However,no significant difference was found in the staining area of VEGF between the ApoE-/-mice with normal diet group and the C57BL/6 normal diet group ([17 854±2967] μm2 vs.[17 116±2023] μm2) (P＞0.05).Significant elevation was also seen in the staining area of VEGFR-2 in the retinal OPL of the ApoE-/-mice of the high fat diet group (12 193±3806)μm2 and the ApoE-/-mice of the normal diet group (11 969± 3616)xm2 compared with C57BL/6 mice of the normal diet group (5387±2225)μm2(all at P＜0.01).The relative expression values (VEGF/β-actin) of VEGF in the retinas were (1.51 ±0.32) and (1.17±0.39) in the ApoE-/-mice of the high fat diet group and the normal diet group,respectively,showing a significant increase in comparison with (0.28±0.14) of the C57BL/6 normal diet group (P＜0.01).Conclusions The expression of VEGF and VEGFR-2 in the retinas increases in the ApoE-/-mouse,which leads to the enlargement of MVD and MVA in the retinal OPL and subsequent RAP occurrence.