No abstract

The gonadotropin-releasing hormone agonist (GnRHa; Buserelin) rescues fertility during adulthood in the majority of high infertility risk cryptorchid boys presenting with defective mini-puberty. However, the molecular events governing this effect are not understood. We report the outcome of an RNA profiling analysis of testicular biopsies from 4 operated patients who were treated with GnRHa for 6 months versus 3 operated controls who were not treated. GnRHa induces a significant transcriptional response, including protein-coding genes involved in pituitary development, the hypothalamic-pituitary-gonadal axis, and testosterone synthesis. Furthermore, we observed an increased abundance of long noncoding RNAs (lncRNAs) participating in epigenetic processes, including AIRN, FENDRR, XIST, and HOTAIR. These data are consistent with the hypothesis that hypogonadotropic hypogonadism in boys with altered mini-puberty is the consequence of a profoundly altered gene expression program involving protein-coding genes and lncRNAs. Our results point to molecular mechanisms that underlie the ability of GnRHa to rescue fertility.

The whole genome RNA profiling of testicular biopsies by DNA strand-specific RNA sequencing was examined to determine a potential causative role of isolated congenital cryptorchidism in azoospermia and/or infertility in the context of our previously published GeneChip data. Cryptorchid patients, aged 7 months to 5 years and otherwise healthy, were enrolled in this prospective study. During surgery, testicular tissue biopsies were obtained for histological examination and RNA sequencing. Fifteen patients were selected based on the histological results and were divided into 2 groups. Seven were classified as belonging to the high infertility risk (HIR) and 8 to the low infertility risk (LIR) group. Cryptorchid boys in the HIR group lacked transformation of gonocytes into Ad spermatogonia due to impaired mini-puberty. This group of patients will be infertile despite successful surgery. The new important finding was a decreased PROK2, CHD7, FGFR1, and SPRY4 gene expression in the HIR group. Furthermore, identification of multiple differences in gene expression between HIR and LIR groups underscores the importance of an intact hypothalamic-pituitary-gonadal axis for fertility development. Our RNA profiling data strongly support the theory that in the HIR group of cryptorchid boys insufficient PROK2/CHD7/FGFR1/SPRY4 gene expression induces deficient LH secretion, resulting in impaired mini-puberty and infertility. We therefore recommend hormonal treatment for this cohort of cryptorchid boys with defective mini-puberty following a seemingly successful orchidopexy.

No abstract

Defective mini-puberty results in insufficient testosterone secretion that impairs the differentiation of gonocytes into dark-type (Ad) spermatogonia. The differentiation of gonocytes into Ad spermatogonia can be induced by administration of the gonadotropin-releasing hormone agonist, GnRHa (Buserelin, INN)). Nothing is known about the mechanism that underlies successful GnRHa treatment in the germ cells. Using RNA-sequencing of testicular biopsies, we recently examined RNA profiles of testes with and without GnRHa treatment. Here, we focused on the expression patterns of known gene markers for gonocytes and spermatogonia, and found that DMRTC2, PAX7, BRACHYURY/T, and TERT were associated with defective mini-puberty and were responsive to GnRHa. These results indicate novel testosterone-dependent genes and provide valuable insight into the transcriptional response to both defective mini-puberty and curative GnRHa treatment, which prevents infertility in man with one or both undescended (cryptorchid) testes.