INTEGRATED TRANSCRIPTOMIC AND FUNCTIONAL ANALYSIS OF OMENTIN-1 ACTION ON GNRH SIGNALING IN MOUSE NEURONS. <EM>IN VITRO</EM> STUDIES ON GT1-7 CELLS

Omentin-1 (OMNT1) is an adipokine implicated in metabolic homeostasis and reproductive function; however, its role in hypothalamic GnRH neurons remains poorly defined. We hypothesized that OMNT1 alters the transcriptomic profile of GnRH neurons, thereby modulating intracellular signaling pathways regulating GnRH synthesis and secretion. The study was conducted using the mouse hypothalamic GnRH neuronal GT1-7 cell line. Transcriptomic analysis was performed following OMNT1 treatment (100 ng/mL) using next-generation sequencing to identify differentially expressed genes and enriched biological pathways, supported by DAVID, KEGG, GeneMANIA, and Reactome databases. Functional validation included dose- (10, 50, 100 ng/mL) and time-dependent (15 min, 30 min, 24 h) analyses of Gnrh1 mRNA expression (RT-qPCR), GnRH protein levels (Western blot), and GnRH secretion (ELISA). Activation of intracellular signaling pathways was assessed by measuring cAMP levels (ELISA) and phosphorylation of ERK1/2 and PKC (Western blot; n ≥ 3; p<0.05). Pharmacological inhibitors of ERK1/2 and PKC were used to determine their involvement in OMNT1-mediated regulation of GnRH secretion. Transcriptomic profiling revealed that OMNT1 significantly regulated 863 genes (382 downregulated and 481 upregulated), mainly associated with signal transduction, calcium signaling, cytoskeletal organization, and protein/GTP binding. Functionally, OMNT1 reduced Gnrh1 mRNA levels after 30 min and 24 h, whereas GnRH protein levels increased after 15- and 30-min. GnRH secretion was stimulated after 30 min. OMNT1 activated cAMP, ERK1/2, and PKC signaling, and inhibition of ERK1/2 or PKC reduced OMNT1-induced GnRH secretion. This study identifies OMNT1 as a metabolic regulator of GnRH neurons, linking transcriptomic remodeling with ERK1/2- and PKC-dependent GnRH signaling.
Funding: 2024/53/N/NZ9/01916