Expressão dos microRNAs hsa-378a-3p,hsa-miR-942-5p e hsa-miR-668-3pe de seus genes alvosCCR7, IKBKBe PLA2G2D na síndrome de down

Abstract

Down syndrome (DS), caused by trisomy of chromosome 21, has an occurrence of approximately one in 800 live births. Several clinical manifestations are observed in individuals with the syndrome, including changes in the immune system. The immune system impaired in Down syndrome can contribute to the increase in susceptibility to infections; one of the main causes of hospitalization and death of individuals with DS. Trisomy 21 can cause global changes in gene expression, including those not located on chromosome 21, which regulate immune / inflammatory processes and other physiological mechanisms. Objective: To validate, in a larger group of individuals with DS, the relative expression of miRNAs and genes, involved in inflammatory / immunological pathways, which showed altered expression in six children with DS in our previous studies and who also showed association by in silico prediction. Material and Methods: The in silico prediction of the miRNA target genes was performed using the online database DIANA-MicroT-CDS v.5.0 considering the score 0.8 the as cutoff value (threshold). To confirm the differential expression of the target miRNA genes predicted by in-silico analysis, RNA samples were obtained from peripheral blood mononuclear cells (PBMC) from 67 children with DS (case group) and 60 children without the syndrome (control group). The age comparison between the groups was performed using Anderson Darling and Man-Whitney test in the Graph PadPrism version 8.0 program. The expression of the hsa-miR-378a-3p, hsa-miR-942-5p and hsa-miR-668-3p miRNAs and the CCR7, IKBKB and PLA2G2D genes were analyzed by quantitative polymerase chain reaction (qPCR), using Taqman assays in the StepOnePlus Real-Time PCR system. The gene expression data were normalized by the application of the Anderson Darling test, and statistical analysis was performed using the Onesample T test, adopting a value of α = 0.05, in the GraphPad Prism software version 8.0. Results: In silico prediction has identified the existence of a possible interaction between three miRNAs and three genes differentially expressed in previous studies in DS. Two of the microRNAs evaluated (hsa-miR-942-5p and hsa-miR-668-3p) did not show statistically significant difference between the case and control groups. Individuals with DS showed increased expression of the hsa-miR-378a-3p miRNA and decreased expression of the CCR7, IKBKB and PLA2G2D genes. Conclusion: Children with DS have, in relation to children without the syndrome, reduced expression of the CCR7, IKBKB and PLA2G2D genes and increased expression of the hsa-miR-378a-3p miRNA, not located on chromosome 21, which may contribute to disability of immunological / inflammatory processes in DS.