Neuropeptidomic analysis of the embryonic Japanese quail diencephalon
1 Department of Pharmaceutical Biosciences, division of toxicology, Uppsala University, The Biomedical Center, Husargatan 3, Box 594, SE-75124 Uppsala, Sweden
2 Department of Pharmaceutical Biosciences, Medical Mass Spectrometry, Uppsala University, The Biomedical Center, Husargatan 3, Box 583, SE-75123 Uppsala, Sweden
3 Department of Environmental Toxicology, Uppsala University, Norbyvägen 18A, SE-75236 Uppsala, Sweden
4 Department of Cellular and Molecular Biology, Uppsala University, The Biomedical Center, Husargatan 3, Box 596, SE-75124 Uppsala, Sweden
5 Denator AB (since 2006), Uppsala Science Park, Dag Hammarskjolds road 32A, SE 751 83 Uppsala, Sweden
6 Centre for Reproductive Biology in Uppsala
BMC Developmental Biology 2010, 10:30 doi:10.1186/1471-213X-10-30Published: 18 March 2010
Endogenous peptides such as neuropeptides are involved in numerous biological processes in the fully developed brain but very little is known about their role in brain development. Japanese quail is a commonly used bird model for studying sexual dimorphic brain development, especially adult male copulatory behavior in relation to manipulations of the embryonic endocrine system. This study uses a label-free liquid chromatography mass spectrometry approach to analyze the influence of age (embryonic days 12 vs 17), sex and embryonic day 3 ethinylestradiol exposure on the expression of multiple endogenous peptides in the developing diencephalon.
We identified a total of 65 peptides whereof 38 were sufficiently present in all groups for statistical analysis. Age was the most defining variable in the data and sex had the least impact. Most identified peptides were more highly expressed in embryonic day 17. The top candidates for EE2 exposure and sex effects were neuropeptide K (downregulated by EE2 in males and females), gastrin-releasing peptide (more highly expressed in control and EE2 exposed males) and gonadotropin-inhibiting hormone related protein 2 (more highly expressed in control males and displaying interaction effects between age and sex). We also report a new potential secretogranin-2 derived neuropeptide and previously unknown phosphorylations in the C-terminal flanking protachykinin 1 neuropeptide.
This study is the first larger study on endogenous peptides in the developing brain and implies a previously unknown role for a number of neuropeptides in middle to late avian embryogenesis. It demonstrates the power of label-free liquid chromatography mass spectrometry to analyze the expression of multiple endogenous peptides and the potential to detect new putative peptide candidates in a developmental model.