The Exploration of Disturbance of Capillary and Photoreceptor Communication Networks in Diabetic Retinopathy Through Single‐Cell RNA‐Seq

This study investigates the differences in ligand-receptor interactions between the communication network of vascular endothelial cells (ECs) and photoreceptor cells (PRCs)in diabetic retinopathy (DR) the mechanism was verified by animal experiments. The GSE209872 data set, including retinal specimens from five Sprague-Dawley rats induced by streptozotocin, was obtained from Gene Expression Omnibus. CM and EC data were extracted individually for reclustering, functional enrichment and trajectory analyses. Cell communication analysis was conducted to investigate the altered signals and significant ligand-receptor interactions. Moreover, novel ligand-receptor interactions were validated using immunofluorescence staining using 2, 4 and 8 weeks DR model; DR was treated with AAV-shANGPTL4, and retinal function was detected by Haematoxylin and eosin staining (HE), TUNEL and ELISA. The expression of ligand-receptor in DR Retina was detected by qPCR and immunohistochemistry. Nine cell types were determined in DR. Cellular communication results revealed four signalling pathways, including PTN, MK, ANGPTL and CXCL, that were significantly changed in DR. Furthermore, 3 ligand-receptor pairs (Ptn-Ncl, Mkd-Ncl and Angptl4-Sdc4) were obviously upregulated between ECs and PRCs, the expression of which was verified via immunofluorescence in the DR model. After treatment with AAV-shANGPTL4, the retinal thickness and average density of RGCs were decreased (p < 0.05). TUNEL staining showed that knocking down ANGPTL4 reduced the apoptosis of DR (p < 0.05), and VEGF and IGF-1 expression were downregulated (p < 0.01). The expression of ligand-receptors also decreased in the DR Model (p < 0.01). The vascular ECs and PRCs demonstrate significant heterogeneities in DR. ANGPTL4 was a decreased ligand-receptor expression and improved retinal function as a potential therapeutic target against DR.