Network Pharmacology Combined with Transcriptional Analysis to Unveil the Biological Basis of Astaxanthin in Reducing the Oxidative Stress Induced by Diabetes Mellitus

PURPOSE: Astaxanthin (Ast) has been reported to reduce oxidative stress induced by diabetes mellitus (DM). The aim of this research was to give a systematic overview of the biological basis for this process. METHODS: Ast-targeted proteins were collected from the BATMAN database, Comparative Toxicogenomics Database, and STITCH database. Putative DM-related protein targets were collected from the GeneCards database. A DM-rat model was then built with streptozotocin (STZ) combined with a high-sugar, high-fat diet for 30 days. Total cholesterol (TC), triglycerides (TGs), and insulin levels were examined using whole tail-vein blood from overnight-fasted rats. SOD, GSH, and MDA activy was detected in liver tissue (p<0.05). In addition, we used RNA-sequencing analysis to detect gene-transcription level in liver tissue of rats and GO biological process analysis to show all the log(2)FC≥2 genes in the Ast-fed DM rats compared with the DM group using the STRING database. Ast-intersecting targets were collected with Venn analysis. Docking analysis between Ast and targeted proteins was down with the SwissDock server. Ast targets–pathway networks were built using Cytoscape 3.7.2 software. RESULTS: A total of 120 Ast-targeted proteins and 13,784 DM-related targets were collected. Ast functioned in reducing TC, TG, and MDA levels, promoting SOD activity and GSH expression, and alleviating islet-cell injury in Ast-fed DM rats compared with DM control rats. Furthermore, genes involved in MAPK, TNF, AMPK, and FOXO signaling pathways were differently expressed in Ast-treated DM rats compared with DM rats. The differentially expressed genes were enriched in euchromatin, thyroid cancer, and metaphase-plate congression. Three Ast-intersecting targets — Col5A1, Nqo1, and Notch2 — were then identified. We found possible binding patterns of Ast with Nqo1 and Notch2, respectively. Ast targets–pathway networks were finally built to show a systematic overview of how Ast works in multiple pathways to reduce oxidative stress. Taken together, Ast is predicted to target Col5A1, Nqo1, and Notch2 to form a network of systemic pharmacological effects to: 1) promote insulin-releasing balance and relieve insulin resistance, 2) reduce testicular cell apoptosis, and 3) maintain normal size in marginal-zone B cells and inhibit autoimmune DM, all of which contribute to the balance of lipid metabolism and reduction of oxidative stress in DM patients. CONCLUSION: Ast functions in reducing oxidative stress in DM rats by regulating a variety of targets to form a comprehensive antioxidative network.