Background: Diabetic retinopathy (DR) is currently the leading cause of blindness and visual disability in adults with diabetes mellitus (DM). Neovascularization has been identified as an important clinical property in DR, however, the exact mechanisms in DR neovascularization are still unclear and need further elucidation. Methods: Quantitative real-time PCR (qRT-PCR) was conducted to detect the expression level of long non-coding RNA (lncRNA)-metastasis associated lung adenocarcinoma transcript 1 (MALAT1), miR-125b and vascular endothelial-cadherin (VE-cadherin) in human retina microvascular endothelial cells (hRMECs) treated with high glucose (HG). Luciferase assay was used to detect interaction of MALAT1 with miR-125b and miR-125b with VE-cadherin. MTT assay, transwell assay, tube formation assay and vascular permeability assay were conducted to detect the cell viability, migration tube formation ability and permeability of hRMECs, respectively. ELISA was used to examine the release of VE-cadherin and vascular endothelial growth factor (VEGF). Western blotting was used to access the protein expression of VE-cadherin, VEGF, β-catenin, matrix metalloproteinase (MMP) 2 (MMP2) and MMP9. Results: MALAT1 and VE-cadherin were up-regulated while miR-125b was down-regulated in hRMECs treated with HG. MALAT1 could competitively bind to miR-125b against VE-cadherin at the site of 3′-untranslated region (3′-UTR), leading to the up-regulation of VE-cadherin. Knockdown of MALAT1 inhibited the proliferation, migration, tube formation and vascular permeability of hRMECs induced by HG through up-regulating miR-125b. Furthermore, we found the deletion of MALAT1 suppressed the VE-cadherin/β-catenin complex and neovascularization related proteins expression, which was up-regulated by HG. Conclusion: Knockdown of MALAT1 inhibited cell proliferation, migration and angiogenesis of hRMECs via suppressing the VE-cadherin/β-catenin complex through targeting miR-125b. Inhibition of MALAT1 may serve as a potential target for anti-angiogenic therapy for DR.

The glomerular filtration barrier (GFB) produces primary urine and is composed of a fenestrated endothelium, a glomerular basement membrane (GBM), podocytes, and a slit diaphragm. Impairment of the GFB leads to albuminuria and microhematuria. The GBM is generated via secreted proteins from both endothelial cells and podocytes and is supposed to majorly contribute to filtration selectivity. While genetic mutations or variations of GBM components have been recently proposed to be a common cause of glomerular diseases, pathways modifying and stabilizing the GBM remain incompletely understood. Here, we identified prolyl 3-hydroxylase 2 (P3H2) as a regulator of the GBM in an a cohort of patients with albuminuria. P3H2 hydroxylates the 3′ of prolines in collagen IV subchains in the endoplasmic reticulum. Characterization of a P3h2^ΔPod mouse line revealed that the absence of P3H2 protein in podocytes induced a thin basement membrane nephropathy (TBMN) phenotype with a thinner GBM than that in WT mice and the development of microhematuria and microalbuminuria over time. Mechanistically, differential quantitative proteomics of the GBM identified a significant decrease in the abundance of collagen IV subchains and their interaction partners in P3h2^ΔPod mice. To our knowledge, P3H2 protein is the first identified GBM modifier, and loss or mutation of P3H2 causes TBMN and focal segmental glomerulosclerosis in mice and humans.

Background: High myopia (HM) is a leading cause of blindness that has a strong genetic predisposition. However, its genetic and pathogenic mechanisms remain largely unknown. Thus, this study aims to determine the genetic profile of individuals from two large Chinese families with HM and 200 patients with familial/sporadic HM. We also explored the pathogenic mechanism of HM using HEK293 cells and a mouse model.Methods: The participants underwent genome-wide linkage analysis and exome sequencing. Visual acuity, electroretinogram response, refractive error, optical parameters and retinal rod cell genesis were measured in knockout mice. Immunofluorescent staining, biotin-labelled membrane protein isolation and electrophysiological characterisation were conducted in cells transfected with overexpression plasmids.Results: A novel HM locus on Xp22.2-p11.4 was identified. Variant c.539C>T (p.Pro180Leu) inGLRA2gene was co-segregated with HM in the two families. Another variant, c.458G>A (p.Arg153Gln), was identified in a sporadic sample. TheGlra2knockout mice showed myopia-related phenotypes, decreased electroretinogram responses and impaired retinal rod cell genesis. Variants c.458G>A and c.539C>T altered the localisation of GlyRα2 on the cell membrane and decreased agonist sensitivity.Conclusion: GLRA2was identified as a novel HM-causing gene. Its variants would cause HM through altered visual experience by impairing photoperception and visual transmission.