Heterogeneity of sex-biased miRNAs profiling of Cynoglossus semilaevis between exosome and sperm

The occurrence of pseudomales in Cynoglossus semilaevis is a response of sex trait variation to environmental changes, although it brought the uneconomical impact that pseudomales without growth advantage occupied a high proportion in the population. Specificity of spatiotemporal distribution of miRNA is the premise for its transcriptional regulation. Under different conditions, distribution and expression levels of the differential miRNAs in semen reflect the body's active adaptation to environmental changes, and this adaptation has an inheritance of offspring. To evaluate the effect of heterogeneity of adjacent mediums on miRNA sexual expression profiling in semen of C. semilaevis, integrated analysis of comparative miRomic profiling between seminal plasma exosomes and sperm from male and pseudomale C. semilaevis respectively has been performed. The relative expression levels of the major highly expressed known miRNAs revealed that the heterogeneity of miRNAs between adjacent mediums of semen was greater than that between the different sexes. Furthermore, sex-biased miRNAs identified between sperm and exosomes demonstrated that seminal plasma exosomes had higher accumulation efficiency for differential miRNAs than sperm with conditions altered or traits considered. 37 coordinated miRNAs in two medium types including 30 up-coordinated miRNAs and seven down-coordinated miRNAs had significantly different expression levels between males (ZZ) and pseudomales (ZW), so did the 21 opposite differential expressed miRNAs from two mediums. One target of down-coordinated miR-210-3p, was dmrt3, which was an important sex regulatory gene in teleost. GO and KEGG pathway enrichment analysis of targets of 37 coordinated miRNAs showed functions were mainly involved in signal transduction, cell community and biological regulation, while 21 opposite differential expressed miRNAs' targets were mainly enriched into signal transduction, amino acid and lipid metabolism pathways. PCA of sperm and exosomes implied that four sex-biased miRNAs with significantly differential expression to a wider range of other C. semilaevis samples, respectively, although the confidence level decreases greatly with the increase of sample size, suggesting that the sex-biased candidate markers here had the limitation of test range. Overall, this study revealed the effect of heterogeneity of medium on sex-biased miRNA specific expression profile in C. semilaevis and also provided a clue for the medium selection of biomarker development.