Identification of Differentially Expressed Genes in Human Testis Biopsies with Defective Spermatogenesis

The study was designed to identify differences in the expressed transcriptome of the two pathological human testis sample groups compared to normal spermatogenesis samples, with the objective of discovering genes related to the pathological condition. Transcriptional differences in human testis biopsies collected from men with normal spermatogenesis (NSP, n=3; intact germ cells, clinical score - 10), spermatid arrest (SDA, n=2; contains somatic cells and germ cells up to round spermatids, clinical score – 4-5) and Sertoli cell-only (SCO, n=2; complete absence of germ cells, clinical score - 0) phenotypes were assessed by RNA sequencing. A total of over 49 million reads were generated in NSP samples, over 24 million reads in SDA samples, and over 13 million reads in SCO samples. Differentially expressed genes (DEG) were identified based on a mean minimum count => 5, FDR <= 0.05 and log2FC fold change of >0.585 or <-0.585. Genes differentially expressed in pathological groups SDA and SCO compared to NSP, and genes differentially expressed in between the two pathological groups SDA and SCO were filtered. The study discovered a number of significantly differentially expressed genes (DEG) between groups as follows: NSP vs SDA n=1,873; SDA vs SCO n= 4,017; and NSP vs SCO n=10,253. A number of genes (n=10) were selected for further analysis by qRT-PCR and the detection of the protein (n=2) localization in testis by immunohistochemistry.