OBJECTIVEVascular endothelial growth factor (VEGF-A or VEGF) is a major pathogenic factor and therapeutic target for diabetic retinopathy (DR). Since VEGF has been proposed as a survival factor for retinal neurons, defining the cellular origin of pathogenic VEGF is necessary for the effectiveness and safety of long-term anti-VEGF therapies for DR. To determine the significance of Müller cell-derived VEGF in DR, we disrupted VEGF in Müller cells with an inducible Cre/lox system and examined diabetes-induced retinal inflammation and vascular leakage in these conditional VEGF knockout (KO) mice.RESEARCH DESIGN AND METHODSLeukostasis was determined by counting the number of fluorescently labeled leukocytes inside retinal vasculature. Expression of biomarkers for retinal inflammation was assessed by immunoblotting of TNF-α, ICAM-1, and NF-κB. Vascular leakage was measured by immunoblotting of retinal albumin and fluorescent microscopic analysis of extravascular albumin. Diabetes-induced vascular alterations were examined by immunoblotting and immunohistochemistry for tight junctions, and by trypsin digestion assays for acellular capillaries. Retinal integrity was analyzed with morphologic and morphometric analyses.RESULTSDiabetic conditional VEGF KO mice exhibited significantly reduced leukostasis, expression of inflammatory biomarkers, depletion of tight junction proteins, numbers of acellular capillaries, and vascular leakage compared to diabetic control mice.CONCLUSIONSMüller cell-derived VEGF plays an essential and causative role in retinal inflammation, vascular lesions, and vascular leakage in DR. Therefore, Müller cells are a primary cellular target for proinflammatory signals that mediates retinal inflammation and vascular leakage in DR.

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Background Circular RNAs (circRNAs) play crucial roles in the development and progression of human cancers, including non-small cell lung cancer (NSCLC). However, most of these circRNAs, such as hsa_circ_0014235, are not fully identified in functions and mechanisms. Methods The isolated exosomes from serum specimens were identified using transmission electron microscopy (TEM). The expression of hsa_circ_0014235, miR-520a-5p and cyclin-dependent kinase 4 (CDK4) was detected by real-time quantitative polymerase chain reaction (qPCR). For functional assays, cell proliferation, colony formation ability, migration, invasion, cell apoptosis and cell cycle progression were determined using cell counting kit-8 (CCK-8) assay, colony formation assay, wound healing assay, transwell assay and flow cytometry assay, respectively. The expression of CDK4 and other indicated marker proteins was detected by western blot. The predicted target relationship between miR-520a-5p and hsa_circ_0014235 or cyclin-dependent kinase 4 (CDK4) was verified by dual-luciferase reporter assay or RNA immunoprecipitation (RIP) assay. Results The expression of hsa_circ_0014235 was notably elevated in NSCLC serum-derived exosomes, tumor tissues and cells. NSCLC serum-derived exosomes promoted NSCLC cell resistance to cisplatin (DDP), cell proliferation, migration and invasion in vitro, as well as tumor growth and DDP resistance in vivo. Hsa_circ_0014235 overexpression enhanced DDP resistance and facilitated cell malignant behaviors. MiR-520a-5p was a target of hsa_circ_0014235, and rescue experiments showed that miR-520a-5p restoration reversed the effects of hsa_circ_0014235 overexpression. Moreover, CDK4 was a target of miR-520a-5p, and rescue experiments showed that CDK4 knockdown reversed the aggressive effects of miR-520a-5p inhibition on NSCLC progression. Conclusions Exosome-transmitted hsa_circ_0014235 promoted NSCLC malignant development by mediating the miR-520a-5p/CDK4 regulatory axis.

Diabetic retinopathy (DR) is one of the most common diabetic eye diseases and a leading cause of blindness. It is characterized by changes in the blood vessels of the retina. The pathogenesis of DR is complex and to date, the precise mechanisms involved remain unclear. Previous studies have reported that DR is associated with neurodegeneration and that apoptosis may occur in diabetic retinas. In the present study, retinal neurons under conditions of hyperglycemia were used as a model to study apoptosis in diabetic retinas. Retinal neurons exposed to hyperglycemia exhibited high levels of apoptosis. Brain‑derived neurotrophic factor (BDNF), a member of the neurotrophin family, was effective in protecting retinal neurons from hyperglycemia in vitro. BDNF promoted neuronal cell survival in a concentration‑dependent manner. In addition, BDNF was demonstrated to promote the expression of tropomyosin‑related kinase B (TrkB) and elevate the phosphorylation levels of TrkB and ERK in retinal neurons exposed to hyperglycemia. The results of the present study demonstrated that BDNF may protect retinal neurons from hyperglycemia via the TrkB/ERK/MAPK pathway and provides novel insights into the pathogenesis of DR.

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