Functional neuropeptidomics in invertebrates

Abstract

Neuropeptides are key messengers in almost all physiological processes. They originate from larger precursors and are extensively processed to become bioactive. Neuropeptidomics aims to comprehensively identify the collection of neuropeptides in an organism, organ, tissue or cell. The neuropeptidome of several invertebrates is thoroughly explored since they are important model organisms (and models for human diseases), disease vectors and pest species. The charting of the neuropeptidome is the first step towards understanding peptidergic signaling. This review will first discuss the latest developments in exploring the neuropeptidome. The physiological roles and modes of action of neuropeptides can be explored in two ways, which are largely orthogonal and therefore complementary. The first way consists of inferring the functions of neuropeptides by a forward approach where neuropeptide profiles are compared under different physiological conditions. Second is the reverse approach were neuropeptide collections are used to screen for receptor-binding. This is followed by localization studies and functional tests. This review will focus on how these different functional screening methods contributed to the field of invertebrate neuropeptidomics and expanded our knowledge of peptidergic signaling. This article is part of a Special Issue entitled: Neuroproteomics: Applications in Neuroscience and Neurology.

Transcriptomic characterization and curation of candidate neuropeptides regulating reproduction in the eyestalk ganglia of the Australian crayfish, Cherax quadricarinatus

“…By binding to receptors in target tissues, neuropeptides elicit a number of downstream cascades including changes in secondary messengers, phosphorylation and eventually altered transcription activity which leads to a biological response4. In silico neuropeptidome research aimed at understanding different physiological aspects of crustacean biology has been extensively studied in several crustacean species, including Scylla paramamosain 5, Macrobrachium rosenbergii 6, Procambarus clarkii 7, Homarus americanus and Sagmariasus verreauxi 89.…”

Diet-responsive Transcriptional Regulation of Insulin in a Single Neuron Controls Systemic Metabolism

“…Pro-neuropeptide processing includes peptide cleavage, such as removal of the c-peptide in INS-1, and formation of disulphide bonds. In addition to this, neuropeptides may undergo potential modifications such as acetylation, phosphorylation, glycosylation, and amidation (Van Bael et al, 2018a), which may change the bioactivity of the neuropeptide (reviewed in (De Haes et al, 2015)). For example, Leinwald and Chalasani (Leinwand and Chalasani, 2014) suggest that the processing of the INS-6 pro-peptide by different enzymes may lead to INS-6 becoming amidated in the ASI neurons, but not in ASE neurons -which could generate INS-6 neuropeptides with different stabilities and modes of action from the same INS-6 propeptide (Hung et al, 2013;Leinwand and Chalasani, 2013).…”

Peptidomics for the discovery and characterization of neuropeptides and hormones

“…The demand for peptide-relevant, in-depth quantitative assays has stimulated the development of quantitative MS approaches (reviewed by Romanova and co-authors [11]). Differential peptidomics compares qualitatively or quantitatively detectable peptides (Figure 2) between experimental sample groups, either to test or generate hypotheses on the functional connections of detected peptides, or to correlate peptide levels to the biological paradigms under investigation [10]; these investigations can be performed on a global scale [30–32, 51–53] or selectively [54]. The intensity of the observed intact peptide ions, or frequency of fragmentation events during chromatographic separation, serves as a basis for peptide level comparisons.…”

“…In the intervening 15 years since the ground-breaking publications in the field, peptidomics has blossomed into a multitude of distinct approaches (Figure 1B), designed to accommodate a range of sample-related issues (chemical and anatomical complexity, difficulty of sampling, size and/or volume) and a lack of prior knowledge on the peptides expressed in the sample [8–10]. The quantitative capability of peptidomics has become more refined and reliable [11–13].…”