Neurotensin expressed in the granulosa cells regulates selective genes that are potentially involved in the ovulatory process

Neurotensin (NTS) is a small 13 amino acid neuropeptide. In the mouse ovary, the expression of Nts ovary increases 250-fold 4h after hCG. Similarly, in granulosa cells, the mRNA levels of Nts increased rapidly at 4h after hCG stimulation. Interestingly, the Nts mRNA levels in granulosa cells were approximately 8-fold higher at 4 h after hCG than in whole ovaries. However, the potential mechanisms of NTS action in the ovulatory process are unknown. The present study determined the regulatory mechanisms driving the expression of Nts and functions of the NTS using primary mouse granulosa cells. hCG activated PKA and p38MAPK signaling pathways, and inhibitors for these pathways abolished hCG-induced increases in the levels of Nts. To identify the genes regulated by NTS, high throughput RNA sequencing was performed using Nts silenced mouse granulosa cells treated with or without hCG. Sequencing data analysis revealed that Nts knockdown affects the expression of several genes that were not previously identified in the ovary. qPCR analysis verified hCG-induced, Nts-regulated expression of a selection of these genes. This study revealed novel genes regulated by NTS, thereby providing a function for NTS in the ovulatory process. Overall design: Cultured mouse granulosa cells transfected either with siRNA negative control (si-NC) or siRNA specific to mouse Nts (si-Nts) and treated with or without hCG were used to perform RNA-seq analysis.