Putrescine modulates alternative splicing of gonadotropin hormone-releasing hormone (GnRH) through differential regulation of splicing factors

Gonadotropin-releasing hormone (GnRH) plays a critical role in reproductive function, with its activity influenced by differential splicing that generates functionally distinct isoforms. However, the molecular mechanisms regulating GnRH pre-mRNA processing remain poorly understood. In this study, we investigated the effects of putrescine, a biogenic polyamine, on GnRH splicing and the expression of splicing regulatory factors. Transcriptome analysis revealed that putrescine treatment induces significant changes in the expression of splicing-related genes. Notably, putrescine enhanced the expression of both the full-length GnRH isoform (GnRH V1) and an exon-skipped variant (GnRH V2), with the latter exhibiting higher expression levels. Further analysis showed putrescine significantly upregulated key alternative splicing regulators, including SR proteins (SRSF11, SRSF12), RNA helicases (DDX26B, DDX6, DDX25), and Pre-mRNA processing factor (PRPF8), Splicing factor 3b (SF3B2). Conversely, HnRNPA3 and SF3B1 were downregulated. These findings suggest putrescine influences GnRH isoform expression through a dual mechanism: enhancing factors that promote alternative splicing while simultaneously attenuating components of the canonical splicing machinery. Our results provide novel insights into the molecular regulation of GnRH splicing and highlight putrescine as a potential modulator of reproductive function through alternative splicing mechanisms.