NCBI Summary:
The protein encoded by this gene is a member of the chromogranin/secretogranin family of neuroendocrine secretory proteins. Studies in rodents suggest that the full-length protein, secretogranin II, is involved in the packaging or sorting of peptide hormones and neuropeptides into secretory vesicles. The full-length protein is cleaved to produce the active peptide secretoneurin, which exerts chemotaxic effects on specific cell types, and EM66, whose function is unknown. [provided by RefSeq, Jul 2008]
General function
Ligand, Hormone, Cytokine
Comment
Cellular localization
Secreted
Comment
Ovarian function
Ovulation
Comment
Ovulatory induction of SCG2 in human, non-human primate, and rodent granulosa cells stimulates ovarian angiogenesis. Hannon PR et al. (2018) The luteinizing hormone (LH) surge is essential for ovulation, but the intrafollicular factors induced by LH that mediate ovulatory processes (e.g. angiogenesis) are poorly understood, especially in women. The role of secretogranin II (SCG2) and its cleaved bioactive peptide, secretoneurin (SN), were investigated as potential novel mediators of ovulation by testing the hypothesis that SCG2/SN is induced in granulosa cells by human chorionic gonadotropin (hCG), via a downstream LH receptor signaling mechanism, and stimulates ovarian angiogenesis. Humans, non-human primates, and rodents were treated with hCG in vivo resulting in a significant increase in the mRNA and protein levels of SCG2 in granulosa cells collected early during the periovulatory period and just prior to ovulation (humans: 12-34hr; monkeys: 12-36hr; rodents: 4-12hr post-hCG). This induction by hCG was recapitulated in an in vitro culture system utilizing granulosa-lutein cells from in vitro fertilization patients. Using this system, inhibition of downstream LH receptor signaling pathways revealed that the initial induction of SCG2 is regulated, in part, by epidermal growth factor receptor (EGFR) signaling. Further, human ovarian microvascular endothelial cells were treated with SN (1-100ng/ml) and subjected to angiogenesis assays. SN significantly increased endothelial cell migration and new sprout formation, suggesting induction of ovarian angiogenesis. These results are the first to establish that SCG2 is increased in granulosa cells across species during the periovulatory period and that SN may mediate ovulatory angiogenesis in the human ovary. These findings provide new insight into the regulation of human ovulation and fertility.//////////////////