The following is a summary of the “Investigation of the mechanisms leading to human sperm DNA damage based on transcriptome analysis by RNA-seq techniques,” published in the January 2023 issue of Reproductive Biomedicine Online by Zhu, et al.

The DNA fragmentation index (DFI) of the sperm was measured from the obtained samples. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis was used to identify differentially expressed RNA in spermatozoa with a high (DFI 30%, experimental group) or normal (DFI 30%, control group) DFI. In addition, real-time quantitative RT-PCR was used to confirm the differential expression of three RNAs (PMS1, TP53BP1, and TLK2) involved in sperm DNA damage and repair (RT-qPCR).

Together, the two sets of samples yielded a total of 19,970 expressed RNA. There was a statistically significant rise in the expression of 189 RNAs and a decrease in the expression of 163 genes in the experimental group compared to the control group. The results of a Gene Ontology enrichment analysis determined that most of these RNAs functioned in the following biological processes: ATP-dependent transmembrane transport, extracellular exosome, somatic cell DNA recombination, protein binding, cytoplasm, and regulation of localization. 

These RNAs were found to have strong ties to the PI3K-Akt signaling pathway, endocytosis, the p53 signaling system, and the cGMP-PKG signaling circuit, according to the results of a KEGG pathway study. In addition, the RT-qPCR results corroborated the RNA sequencing findings that PMS1, TP53BP1, and TLK2 were all expressed at considerably lower levels in the experimental group compared to the control group (P< 0.01, 0.015, and 0.004, respectively).

RNA-seq technology can potentially reveal previously unknown biomarkers of sperm DNA damage by identifying differentially expressed RNAs associated with DNA damage and repair in sperm.