Transcriptome Analysis to Identify Human Spermatogonial Cells from Sertoli Cell-Only Testes

Purpose: We sought to determine whether gene products from spermatogenic cells could be detected in Sertoli cell-only testes. Transcriptome analysis using next generation sequencing was performed using human testicular samples. Materials and Methods: This study enrolled 20 men with nonobstructive azoospermia with a histological diagnosis of Sertoli cell-only and no germ cells on in vitro fertilization analysis and 5 with obstructive azoospermia and histologically normal spermatogenesis. Individual differences in the transcriptome of obstructive azoospermia testicular tissues generated on the Illumina (R) platform were compared as the number of fragments per kilobase of exon per million mapped sequence reads. We confirmed mRNA expression and targeted gene product localization by quantitative reverse transcriptase-polymerase chain reaction and immunohistochemical analysis, respectively. Results: Using next generation sequencing we analyzed 5,666 of the 23,003 screened genes. As representative markers of immature germ cells, UTF1, CD9, DDX4, EPCAM, GFRA1, KIT, LIN28, DMRT, GPR125, UCHL1 and NANOG transcripts were detected in 13 Sertoli cell-only samples (65%). Reverse transcriptase-polymerase chain reaction showed significant mRNA expression of UTF1, CD9, DDX4 and KIT in Sertoli cell-only samples. Immunostaining revealed the localization of DDX4-positive cells, presumably spermatogonia, in 9 Sertoli cell-only samples (45%). These cells lacked proliferative cell nuclear antigen expression. Conclusions: A number of Sertoli cell-only testes contain immature germ cells (spermatogonia and spermatogenic stem cells) with various gene expression profiles. Sertoli cell-only is a heterogeneous pathophysiology which may be corrected by medical treatment or regenerative technologies.