Small RNA in sperm-Paternal contributions to human embryo development.

Sperm not only delivers the paternal genome to the oocyte but also regulatory small RNA (sRNA). However, the role of sRNA in fertilisation and human embryo development remains poorly understood. Here, couples undergoing IVF are recruited, and sperm sRNA analysed to investigate their role in IVF treatment. Differential expression of mitochondrial sRNA and Y-RNA are observed in relation to sperm concentration. For fertilisation rate, sRNA from a single locus are significantly changed. Expression of microRNA (miRNA) and ribosomal sRNA correlates positively and negatively, respectively, to high-quality embryos. Notably, the top miRNA have an area under ROC of >0.8. Predicted targets of these miRNA are relevant for development, suggesting a role for sperm-borne miRNA in embryo development. In conclusion, sperm-borne sRNA are biomarkers for sperm concentration and embryo quality in IVF. These findings may contribute to clinical strategies improving embryo quality, lowering costs and reducing the need for additional treatment cycles.