RNA Sequencing and Bioinformatics Analysis of CircRNAs in Asphyxial Newborns with Acute Kidney Injury

Objective: As one kind of novel non-coding RNA with high stability and conservatism, circular RNAs (circRNAs) are involved in different biological processes. Although growing evidence has supported the important role of circRNAs in renal diseases, the specific mechanism still remains unknown in neonatal acute kidney injury (AKI). Methods: High throughput sequencing analysis was applied to investigate the expression patterns of circRNAs in the comparison between hypoxia induced AKI neonates and controls. Then, bioinformatics analysis was conducted to predict the function of differentially expressed circRNAs and construct the network of circRNA-miRNA interaction. Results: (1) We identified 296 differentially expressed circRNAs (circRNAs with Fold change > 2 and P value < 0.05). Of them, 184 circRNAs were markedly up-regulated and 112 were significantly down-regulated in the AKI group. (2) Bioinformatics analysis indicated that the parental genes of the differentially expressed circRNAs were predominantly implicated in the cell and cell part, cellular process and cancer pathways. Conclusion: This study could contribute to future research of circRNAs in the pathogenesis of neonatal AKI and facilitate the identification of novel therapeutic targets of circRNAs. All AKI samples were obtained from patients in NICU of the First Affiliated Hospital of Nanjing Medical University from October 2020 to November 2021. Blood samples of controls were drawn from mild to moderate indirect hyperbilirubinemia at Obstetrics at the third day after birth. Firstly, to perform the circRNA profile, 2mL peripheral venous blood were drawn from five asphyxia induced AKI infants and five controls. The time point of blood drawing is when the AKI diagnosis was established. Subsequently, peripheral blood samples were collected from 20 asphyxial AKI newborns and 16 controls. Samples were mixed with TRIzol and then frozen in liquid nitrogen until they were tested for circRNA sequencing or quantification.