Polycystic ovary syndrome (PCOS) is the predominant cause of subfertility in reproductive-aged women; however, its pathophysiology remains unknown. Neurotensin (NTS) is a member of the gut-brain peptide family and is involved in ovulation; its relationship with PCOS is unclear. Here, we found that NTS expression in ovarian granulosa cells and follicular fluids was markedly decreased in patients with PCOS. In the in vitro culture of cumulus-oocyte complexes, the neurotensin receptor 1 (NTSR1) antagonist SR48692 blocked cumulus expansion and oocyte meiotic maturation by inhibiting metabolic cooperation and damaging the mitochondrial structure in oocytes and surrounding cumulus cells. Furthermore, the ERK1/2-early growth response 1 pathway was found to be a key downstream mediator of NTS/NTSR1 in the ovulatory process. Animal studies showed that in vivo injection of SR48692 in mice reduced ovulation efficiency and contributed to irregular estrus cycles and polycystic ovary morphology. By contrast, NTS partially ameliorated the ovarian abnormalities in mice with dehydroepiandrosterone-induced PCOS. Our findings highlighted the critical role of NTS reduction and consequent abnormal NTSR1 signaling in the ovulatory dysfunction of PCOS, suggesting a potential strategy for PCOS treatment.
Polycystic Ovary Syndrome/physiopathology* ; Female ; Animals ; Neurotensin/metabolism* ; Receptors, Neurotensin/antagonists & inhibitors* ; Mice ; Ovulation/drug effects* ; Humans ; Granulosa Cells/metabolism* ; Adult ; Oocytes/metabolism* ; MAP Kinase Signaling System ; Signal Transduction ; Follicular Fluid/metabolism* ; Disease Models, Animal ; Gonadotropin-Releasing Hormone/analogs & derivatives*

Neurotensin receptor-1 (NTR1), which can stimulate the intracellular cascade signal pathway, belongs to the large superfamily of G-protein coupled receptors. NTR1 is related to the occurrence and development of several kinds of diseases. In order to screen the inhibitors for the cancers associated with NTR1 protein, we established a CHO (Chinese hamster ovary) cell line in which human neurotensin receptor-1 was highly expressed. The method is to construct the recombinant plasmid which was lysed with the hNTR1 gene and transfect it into CHO cells. After selected with G418, the cell line was evaluated by Western blotting analysis and calcium flux assays. Through the calcium flux assays on FlexStation 3, we got the EC50 value of neurotensin peptide which is the natural NTR1 agonist, and the IC 50 value of SR48692 which is the known NTR1 antagonist. The established human CHO/NTR1 cell line can be used to study the profile of NTR1 biological activity and further screen of NTR1 antagonists and agonists.
Animals ; CHO Cells ; Calcium Signaling ; Cricetinae ; Cricetulus ; Humans ; Pyrazoles ; pharmacology ; Quinolines ; pharmacology ; Receptors, Neurotensin ; antagonists & inhibitors ; genetics ; metabolism ; Transfection