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Analysis of the Whole Transcriptomes of Human Testis with Complete Spermatogenesis and of Human Testes with Sertoli Cell-Only Syndrome

Sertoli cell-only syndrome is severe form of human male infertility in which most seminiferous tubules appear to lack all spermatogenic cells, including spermatogonial stem cells (SSCs). However, a few small tubule segments of some patients have active spermatogenesis and, thus, functional stem cell niches and SSCs. Normally SSCs replicate, migrate and refill adjacent empty niches, but this does not appear to occur in SCO syndrome. We hypothesized that this failure occurs because most niches are dysfunctional. As Sertoli cells are essential to formation of these niches, we used RNAseq to compare the transcriptomes of human testes with qualitatively normal (complete) spermatogenesis (n=4) with the transcriptomes of human testes with SCO syndrome (n=7). We then focused our analysis on the expression of transcripts that bioinformatic analyses identified as Sertoli cell signature transcripts. Results show that Sertoli cells in SCO testes express abnormally low levels of GDNF, FGF8 and BMP4, all of which are important regulators of mouse SSCs and/or progenitor spermatogonia. Sertoli cells in SCO testes express significantly reduced levels of transcripts for proteins that polarize the Sertoli cell plasma membrane and regulate the trafficking of cell adhesion and gap junction proteins in and out of that plasma membrane.