Is secretoneurin a new hormone?

Area of Science:

• Evolutionary biology
• Neuroendocrinology
• Molecular biology

Background:

• Secretogranin II (SgII) is a precursor protein processed into various bioactive peptides.
• Secretoneurin (SN) is a highly conserved peptide segment (31-42 amino acids) derived from SgII, found across vertebrates from sharks to mammals.
• SN exhibits paralogs (SNa, SNb) in teleosts due to genome duplication, and a divergent form in lampreys.

Purpose of the Study:

• To investigate the evolutionary conservation and diverse biological functions of secretoneurin (SN).
• To explore the potential endocrine and neuroregulatory roles of SN.
• To identify novel SN actions and its receptor characteristics.

Main Methods:

• Comparative sequence analysis to identify SN across vertebrate lineages.
• In vivo studies in rodent models to assess neuroinflammatory and angiogenic effects.
• In vitro studies using goldfish and mouse pituitary cells to examine endocrine functions, including luteinizing hormone release.
• Microarray analysis to identify genes regulated by SN in goldfish pituitary cells.
• Behavioral studies in goldfish following intracerebroventricular SN injection.

Main Results:

• SN is a well-conserved peptide across vertebrates, with variations in specific lineages like teleosts and agnathans.
• SN demonstrates regulatory effects on neuroinflammation, neurotransmitter release, and angiogenesis in rodent models.
• SN stimulates luteinizing hormone release in fish and mouse gonadotroph cells, highlighting its role in reproduction.
• SN influences genes in notch signaling and guanylate cyclase pathways in goldfish pituitary cells.
• SN administration increases feeding and locomotion behaviors in goldfish.

Conclusions:

• Secretoneurin (SN) is an evolutionarily ancient peptide with significant, multifaceted roles in neuroendocrine regulation and behavior.
• SN acts as a multifunctional hormone with implications for reproduction, neuroinflammation, and feeding.
• The SN receptor is likely a G-protein coupled protein.
• Further research into SN's functions may reveal novel therapeutic applications.