PUBLICATION

Phoenixin-20 Stimulates mRNAs Encoding Hypothalamo-Pituitary-Gonadal Hormones, is Pro-Vitellogenic, and Promotes Oocyte Maturation in Zebrafish

Authors
Rajeswari, J.J., Unniappan, S.
ID
ZDB-PUB-200422-111
Date
2020
Source
Scientific Reports   10: 6264 (Journal)
Registered Authors
Unniappan, Suraj
Keywords
none
MeSH Terms
  • Animals
  • Cell Line
  • Female
  • Gonadotropin-Releasing Hormone/metabolism
  • Gonads/drug effects
  • Hepatocytes/cytology
  • Hepatocytes/drug effects*
  • Kisspeptins/metabolism
  • Male
  • Oocytes/cytology
  • Oocytes/drug effects*
  • Peptide Hormones/pharmacology*
  • RNA, Messenger/metabolism
  • Vitellogenesis/drug effects*
  • Vitellogenins/metabolism
  • Zebrafish
PubMed
32286445 Full text @ Sci. Rep.
Abstract
Phoenixin-20 (PNX-20) is a bioactive peptide with hormone-like actions in vertebrates. In mammals, PNX stimulates hypothalamo-pituitary-gonadal hormones and regulate reproductive processes. Our immunohisto/cytochemical studies show PNX-like and the putative PNX receptor, SREB3-like immunoreactivity in the gonads of zebrafish, and in zebrafish liver (ZFL) cells. Intraperitoneal injection of zebrafish PNX-20 upregulates mRNAs encoding both salmon gonadotropin-releasing hormone (GnRH), and chicken GnRH-II and kisspeptin and its receptor in zebrafish hypothalamus. Similarly, luteinizing hormone receptor mRNA expression in the testis, follicle-stimulating hormone receptor in the ovary, and the kisspeptin system were upregulated in the gonads of PNX-20 injected fish. We also observed the upregulation of genes involved in the sex steroidogenic pathway (cyp11a1, cyp17a1, 17βhsd, cyp19a1a) in the gonads of PNX-20 administered fish. PNX-20 upregulates the expression of vitellogenin isoforms and estrogen receptor (esr2a and 2b) mRNAs in ZFL cells in vitro. Meanwhile, siRNA-mediated knockdown of PNX-20 resulted in the downregulation of all vitellogenin transcripts, further suggesting its possible role in vitellogenesis. PNX-20 treatment resulted in a significant increase in germinal vesicle breakdown in zebrafish follicles in vitro. Collectively, these results provide strong evidence for PNX-20 effects on the HPG axis and liver to promote reproduction in zebrafish.
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