Comparative distribution and in vitro activities of the urotensin II-related peptides URP1 and URP2 in zebrafish: evidence for their colocalization in spinal cerebrospinal fluid-contacting neurons

PLoS One. 2015 Mar 17;10(3):e0119290. doi: 10.1371/journal.pone.0119290. eCollection 2015.

Abstract

Urotensin II (UII) is an evolutionarily conserved neuropeptide initially isolated from teleost fish on the basis of its smooth muscle-contracting activity. Subsequent studies have demonstrated the occurrence of several UII-related peptides (URPs), such that the UII family is now known to include four paralogue genes called UII, URP, URP1 and URP2. These genes probably arose through the two rounds of whole genome duplication that occurred during early vertebrate evolution. URP has been identified both in tetrapods and teleosts. In contrast, URP1 and URP2 have only been observed in ray-finned and cartilaginous fishes, suggesting that both genes were lost in the tetrapod lineage. In the present study, the distribution of urp1 mRNA compared to urp2 mRNA is reported in the central nervous system of zebrafish. In the spinal cord, urp1 and urp2 mRNAs were mainly colocalized in the same cells. These cells were also shown to be GABAergic and express the gene encoding the polycystic kidney disease 2-like 1 (pkd2l1) channel, indicating that they likely correspond to cerebrospinal fluid-contacting neurons. In the hindbrain, urp1-expressing cells were found in the intermediate reticular formation and the glossopharyngeal-vagal motor nerve nuclei. We also showed that synthetic URP1 and URP2 were able to induce intracellular calcium mobilization in human UII receptor (hUT)-transfected CHO cells with similar potencies (pEC50=7.99 and 7.52, respectively) albeit at slightly lower potencies than human UII and mammalian URP (pEC50=9.44 and 8.61, respectively). The functional redundancy of URP1 and URP2 as well as the colocalization of their mRNAs in the spinal cord suggest the robustness of this peptidic system and its physiological importance in zebrafish.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CHO Cells
  • Cells, Cultured
  • Cerebrospinal Fluid / metabolism*
  • Cricetinae
  • Cricetulus
  • Embryo, Nonmammalian / cytology
  • Embryo, Nonmammalian / metabolism
  • Fluorescent Antibody Technique
  • Humans
  • In Situ Hybridization
  • Intracellular Signaling Peptides and Proteins
  • Neurons / cytology
  • Neurons / metabolism*
  • Peptide Fragments / metabolism*
  • Peptide Hormones / metabolism
  • RNA, Messenger / genetics
  • Real-Time Polymerase Chain Reaction
  • Reverse Transcriptase Polymerase Chain Reaction
  • Rhombencephalon / cytology
  • Rhombencephalon / metabolism*
  • Spinal Cord / cytology
  • Spinal Cord / metabolism*
  • Urotensins / genetics
  • Urotensins / metabolism*
  • Zebrafish / growth & development
  • Zebrafish / metabolism*

Substances

  • Intracellular Signaling Peptides and Proteins
  • Peptide Fragments
  • Peptide Hormones
  • RNA, Messenger
  • UTS2B protein, human
  • Urotensins
  • urotensin II

Grants and funding

This research was supported by funding obtained from the Centre National de la Recherche Scientifique and the Muséum National d’Histoire Naturelle to HT, and from the Institut de la Santé et de la Recherche Médicale, the University of Rouen and the Conseil Régional de Haute-Normandie to CD and IL. CW received financial support from the network Ecole des Neurosciences de Paris (ENP), the Fondation Bettencourt Schueller (FBS), Mr Pierre Belle, the City of Paris Emergence program, the Atip/Avenir junior program from INSERM and CNRS, the Fyssen foundation, the International Reintegration Grant from Marie Curie Actions Framework Program 6, and the European Research Council (ERC) starter grant “OptoLoco”. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.