ARS | Publication request: The neuropeptidomics of Ixodes scapularis synganglion

Submitted to: Journal of Proteomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 10, 2009
Publication Date: August 15, 2009
Citation: Neupert, S., Russell, W.K., Predel, R., Russell, D.H., Nachman, R.J. 2009. The neuropeptidomics of Ixodes scapularis synganglion. Journal of Proteomics. 72:1040-1045.

Interpretive Summary: Because of problems with the development of resistance to conventional pesticides, there is a critical need for new concepts and alternative approaches in controlling tick pests. The basic premise of this research is that neuropeptides (short chains of amino acids) serve as potent messengers in insects and ticks to regulate vital functions. New, selective control measures may be developed by designing metabolically stable mimics of these neuropeptides that actively inhibit or over-stimulate functions regulated by them, resulting in disruption of the internal environment of the insect or tick. The first step is to identify neuropeptide structures in specific insect pests and map sites of production and storage within the nervous system. We report on the identification of neuropeptides of a number of classes from a specific nerve tissue known as the synganglion. We report on the use of state-of-the-art analytical techniques to identify 19 regulatory neuropeptides in the synganglion of a species of tick. A deeper understanding of the specific structures of neuropeptides, where they are stored and released, and how these neuropeptides regulate critical processes in ticks will aid in the design of strategies to disrupt feeding, development, reproduction, and survival. The work brings us one step closer to the development of practical neuropeptide-like substances that will be effective in controlling pest ticks in an environmentally friendly fashion.

Technical Abstract: Ticks (Ixodoidea) likely transmit the greatest variety of human and animal pathogens of any arthropod vector. Despite their medical significance only few data are available about the messenger molecules in the central nervous system that coordinate all physiological processes in these animals, including behaviour. In our study, we performed the first comprehensive neuropeptidomic analysis of any tick species by using MALDI-TOF mass spectrometry. Specifically we analyzed the neuropeptides in the synganglion of Ixodes scapularis. The genome of this species is currently sequenced, it is the first genomic analysis of a member of the large subphylum Chelicerata. For our approach we used informations from predicted neuropeptide precursor sequences found in EST databases (see Christie et al. 2009) as well as data obtained by complete de novo sequencing. The direct tissue profiling yielded 19 neuropeptides from 12 neuropeptide precursors. The sequences of these neuropeptides are not as unique as predicted; a comparison with the peptidome of other invertebrates shows a close relationship with insect neuropeptides. This work will provide a resource for studying tick neurobiology and will hopefully also help to identify novel targets for tick and tick-borne disease control.