MicroRNAs participate in the regulation of apoptosis and oxidative stress-related gene expression in rabbits infected with Lagovirus europaeus GI.1 and GI.2 genotypes

Abstract

MicroRNAs (miRs) are a group of small, 17–25 nucleotide, non-coding RNAthat regulate gene expression at the post-transcriptional level. To date, littleis known about the molecular signatures of regulatory interactions betweenmiRs and apoptosis and oxidative stress in viral diseases. Lagovirus europaeusis a virus that causes severe disease in rabbits (Oryctolagus cuniculus) calledRabbit Hemorrhagic Disease (RHD) and belongs to the Caliciviridae family,Lagovirus genus. Within Lagovirus europaeus associated with RHD, twogenotypes (GI.1 and GI.2) have been distinguished, and the GI.1 genotypeincludes four variants (GI.1a, GI.1b, GI.1c, and GI.1d). The study aimed toassess the expression of miRs and their target genes involved in apoptosisand oxidative stress, as well as their potential impact on the pathwaysduring Lagovirus europaeus—two genotypes (GI.1 and GI.2) infection ofdifferent virulences in four tissues (liver, lung, kidneys, and spleen). Theexpression of miRs and target genes related to apoptosis and oxidativestress was determined using quantitative real-time PCR (qPCR). In this study,we evaluated the expression of miR-21 (PTEN, PDCD4), miR-16b (Bcl-2,CXCL10), miR-34a (p53, SIRT1), and miRs—related to oxidative stress—miR-122 (Bach1) and miR-132 (Nfr-2). We also examined the biomarkers of bothprocesses (Bax, Bax/Bcl-2 ratio, Caspase-3, PARP) and HO-I as biomarkersof oxidative stress. Our report is the first to present the regulatory effectsof miRs on apoptosis and oxidative stress genes in rabbit infection withLagovirus europaeus—two genotypes (GI.1 and GI.2) in four tissues (liver,lungs, kidneys, and spleen). The regulatory effect of miRs indicates that,on the one hand, miRs can intensify apoptosis (miR-16b, miR-34a) in theexamined organs in response to a viral stimulus and, on the other hand, inhibit(miR-21), which in both cases may be a determinant of the pathogenesis ofRHD and tissue damage. Biomarkers of the Bax and Bax/Bcl-2 ratio promotemore intense apoptosis after infection with the Lagovirus europaeus GI.2genotype. Our findings demonstrate that miR-122 and miR-132 regulateoxidative stress in the pathogenesis of RHD, which is associated with tissuedamage. The HO-1 biomarker in the course of rabbit hemorrhagic disease indicates oxidative tissue damage. Our findings show that miR-21, miR-16b,and miR-34a regulate three apoptosis pathways. Meanwhile, miR-122 andmiR-132 are involved in two oxidative stress pathways.