O microRNA bta-miR-425-5p adquirido pelo espermatozoide durante o processo de maturação no epidídimo

Abstract

MiRNAs play key roles in cell function through the regulation of different pathways. Sperm cells can deliver miRNAs to the oocyte modulating the embryo's future epigenetic processes. Particularly miR-425-5p, is well described as a cellular proliferation marker and is known to be present in sperm. This work aimed to determine and quantify whether bta-miR-425-5p, found in bovine sperm, originates from spermatogenesis or is incorporated during epididyma l maturation. For that bull, the testis-epididymis complex was obtained from a local slaughterhouse to obtain sperm, extracellular vesicles, and tissue samples from the testicular parenchyma, epididymal head, body, and tail from 22 testes. Samples were collected by dissection and flushing with 1xPBS. Extracellular vesicles were characterized by TEM, nanoparticle tracking analysis, and flow cytometer, in addition, the expression of bta-miR-425- 5p in extracellular vesicles, sperm, and tissue samples from different epididymal segments and the testis was quantified by RT-qPCR. The results demonstrate the presence of extracellular vesicles and differ in size and concentration for each region, the size of the extracellular vesicles decreased, the largest in the testis and smallest in the epididymal cauda, with greater concentration in the testicles than in the different regions of the epididymis. Even in quantifying the expression of bta-miR-425-5p, this was expressed in the seminiferous tubules and epididymal ducts, and significantly different expressed in the extracellular vesicles and sperm of the epididymal cauda. Overall, this work demonstrated that bta-miR-425-5p was added to spermatozoa during maturation and this aggregation could be mediated by extracellular vesicles.