Apolipoprotein C3 Involved in Diabetic Retinopathy by Promoting Retinal Angiogenesis via Activation of the MYC Pathway

Purpose: To investigate the expression and function of apolipoprotein C3 (APOC3) in diabetic retinopathy (DR). Methods: The quantitative expression of APOC3 in aqueous humor of patients with DR was detected using our proteomic datasets (PXD046630 and PXD053634). A multiplex immunoassay was used to examine the level of APOC3 in serum of patients with DR. Western blot, immunohistochemistry and enzyme-linked immunosorbent assays were used to measure APOC3 expression in liver, duodenum, retina and serum of db/db mice and oxygen induced retinopathy (OIR) mice, and in the human retinal microvascular endothelial cells (hRMECs) exposed to high glucose, hypoxia or both of them. Cell proliferation, migration and tube formation assays were used to assessed the phenotypic characteristics of hRMECs treated with recombinant APOC3 (r-APOC3), hypoxia and both of them. RNA sequence analysis and inhibition assay were conducted to explore the pathway in r-APOC3 and hypoxia stimulation. Results: APOC3 expression were significantly increased in aqueous humor and serum of patients with DR, as well as in liver, duodenum, serum, and retina of db/db mice and OIR mice, while did not markedly change in both hRMECs and their conditioned medium when exposed to high glucose, hypoxia or both of them. r-APOC3 combined with hypoxia significantly enhanced the proliferation, migration and tube formation of hRMECs, and promoted the upregulation of MYC, VEGF and IL6. Inhibition of MYC expression alleviated the phenotypic changes in hRMECs treated with r-APOC3 combined with hypoxia. Purpose: To investigate the expression and function of apolipoprotein C3 (APOC3) in diabetic retinopathy (DR). Methods: The quantitative expression of APOC3 in aqueous humor of patients with DR was detected using our proteomic datasets (PXD046630 and PXD053634). A multiplex immunoassay was used to examine the level of APOC3 in serum of patients with DR. Western blot, immunohistochemistry and enzyme-linked immunosorbent assays were used to measure APOC3 expression in liver, duodenum, retina and serum of db/db mice and oxygen induced retinopathy (OIR) mice, and in the human retinal microvascular endothelial cells (hRMECs) exposed to high glucose, hypoxia or both of them. Cell proliferation, migration and tube formation assays were used to assessed the phenotypic characteristics of hRMECs treated with recombinant APOC3 (r-APOC3), hypoxia and both of them. RNA sequence analysis and inhibition assay were conducted to explore the pathway in r-APOC3 and hypoxia stimulation. Results: APOC3 expression were significantly increased in aqueous humor and serum of patients with DR, as well as in liver, duodenum, serum, and retina of db/db mice and OIR mice, while did not markedly change in both hRMECs and their conditioned medium when exposed to high glucose, hypoxia or both of them. r-APOC3 combined with hypoxia significantly enhanced the proliferation, migration and tube formation of hRMECs, and promoted the upregulation of MYC, VEGF and IL6. Inhibition of MYC expression alleviated the phenotypic changes in hRMECs treated with r-APOC3 combined with hypoxia.