Differential microRNA expression profiles and bioinformatics analysis between young and aging spontaneously hypertensive rats

MicroRNAs (miRNAs/miRs) serve a role as important regulators in cardiac hypertrophy. The present study aimed to reveal the differential expression profile of miRNAs between young and aging spontaneously hypertensive rats (SHRs) and studied the functional annotation of predicted targets. Briefly, 3-month-old and 12-month-old SHRs (n=3/group) were subjected to echocardiography, histopathological analysis and dihydroethidium staining. Subsequently, small RNA sequencing and data processing was conducted to identify the differentially expressed miRNAs between these two groups. Eight significantly upregulated miRNAs were validated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), followed by in silico target gene prediction. Functional annotation analysis of the predicted targets was performed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. As a result, significantly impaired left ventricular diastolic function was detected in the 12-month-old SHRs, alongside increased myocyte cross-sectional area and percentage area of fibrosis, elevated reactive oxygen species production and reduced microvessel density (P<0.05). Compared with the 3-month-old SHRs, 21 miRNAs were significantly upregulated and five miRNAs were downregulated in 12-month-old rats (P<0.05). Eight upregulated, remodeling-associated miRNAs, including rno-miR-132-3p, rno-miR-182, rno-miR-208b-3p, rno-miR-212-3p, rno-miR-214-3p, rno-miR-218a-5p, rno-miR-221-3p and rno-miR-222-3p, underwent bioinformatics analysis. The target genes were significantly enriched in 688 GO terms and 39 KEGG pathways, including regulation of peptidyl-tyrosine phosphorylation, regulation of protein serine/threonine kinase activity, adrenergic signaling in cardiomyocytes, ErbB signaling pathway, mTOR signaling pathway, FoxO signaling pathway, Ras signaling pathway, insulin secretion, adipocytokine signaling pathway, HIF-1 signaling pathway, Rap1 signaling pathway, VEGF signaling pathway and TNF signaling pathway. Collectively, the present study identified a dysregulated miRNA profile in aging SHRs, which targeted numerous signaling pathways associated with cardiac hypertrophy, autophagy, insulin metabolism, angiogenesis and inflammatory response.