Peptidomics of Neuropeptidergic Tissues of the Tsetse FlyGlossina morsitans morsitans

Abstract

Abstract. Neuropeptides and peptide hormones are essential signaling molecules that regulate nearly all physiological processes. The recent release of the tsetse fly genome allowed the construction of a detailed in silico neuropeptide database (International Glossina Genome Consortium, Science 344, 380-386 (2014)), as well as an in-depth mass spectrometric analysis of the most important neuropeptidergic tissues of this medically and economically important insect species. Mass spectrometric confirmation of predicted peptides is a vital step in the functional characterization of neuropeptides, as in vivo peptides can be modified, cleaved, or even mispredicted. Using a nanoscale reversed phase liquid chromatography coupled to a Q Exactive Orbitrap mass spectrometer, we detected 51 putative bioactive neuropeptides encoded by 19 precursors: adipokinetic hormone (AKH) I and II, allatostatin A and B, capability/ pyrokinin (capa/PK), corazonin, calcitonin-like diuretic hormone (CT/DH), FMRFamide, hugin, leucokinin, myosuppressin, natalisin, neuropeptide-like precursor (NPLP) 1, orcokinin, pigment dispersing factor (PDF), RYamide, SIFamide, short neuropeptide F (sNPF) and tachykinin. In addition, propeptides, truncated and spacer peptides derived from seven additional precursors were found, and include the precursors of allatostatin C, crustacean cardioactive peptide, corticotropin releasing factor-like diuretic hormone (CRF/DH), ecdysis triggering hormone (ETH), ion transport peptide (ITP), neuropeptide F, and proctolin, respectively. The majority of the identified neuropeptides are present in the central nervous system, with only a limited number of peptides in the corpora cardiaca-corpora allata and midgut. Owing to the large number of identified peptides, this study can be used as a reference for comparative studies in other insects.

Characterization and pharmacological analysis of two adipokinetic hormone receptor variants of the tsetse fly, Glossina morsitans morsitans

“…Immunohistochemical staining and peptidomics analysis of the corpora cardiaca confirmed the presence of AKH peptides in G. m. morsitans (Attardo et al, 2012;Caers et al, 2015;G€ ade, G., Simek, P., and Marco, H.G., personal communication). Expression of akh genes in samples of the tsetse thorax is most likely due to the presence of cells of the corpora cardiaca, located on the ventro-lateral walls of the aorta in the anterior part of the prothorax.…”

“…An adipokinetic hormone precursor related peptide (APRP) with an as yet undiscovered function is cleaved from the C-termini (De Loof et al, 2009;Hatle and Spring, 1999). Mass spectrometry confirmed posttranslational modifications of the tsetse AKH peptides, including an N-terminal pyroglutamate and a C-terminal amide group which are generally present in insect AKHs (Caers et al, 2015; Simek, P., and Marco, H.G., personal communication).…”

“…These lipids are transported to the uterine gland where they are used as components for "milk" synthesis, the nutrient source for growing larvae (Langley and Bursell, 1980). Previous in silico and peptidomic studies identified two AKH neuropeptides in the tsetse fly Glossina morsitans morsitans (Kaufmann et al, 2009;Caers et al, 2015). One peptide, known as Glomo-AKH I, Glomo-AKH or GmmAKH, has a sequence that differs from any known insect AKH (Kaufmann et al, 2009;Attardo et al, 2012;Caers et al, 2015).…”

“…Previous in silico and peptidomic studies identified two AKH neuropeptides in the tsetse fly Glossina morsitans morsitans (Kaufmann et al, 2009;Caers et al, 2015). One peptide, known as Glomo-AKH I, Glomo-AKH or GmmAKH, has a sequence that differs from any known insect AKH (Kaufmann et al, 2009;Attardo et al, 2012;Caers et al, 2015). A second peptide has a sequence identical to the Phormia terraenovae hyperthrehalosaemic hormone (Phote-HrTH) (G€ ade et al, 1990) and the Drosophila melanogaster adipokinetic hormone (Drome-AKH) (Schaffer et al, 1990), and was previously named Glomo-AKH II, Phote-HrTH or GmmHrTH in tsetse flies (Kaufmann et al, 2009;Attardo et al, 2012;Caers et al, 2015).…”

“…One peptide, known as Glomo-AKH I, Glomo-AKH or GmmAKH, has a sequence that differs from any known insect AKH (Kaufmann et al, 2009;Attardo et al, 2012;Caers et al, 2015). A second peptide has a sequence identical to the Phormia terraenovae hyperthrehalosaemic hormone (Phote-HrTH) (G€ ade et al, 1990) and the Drosophila melanogaster adipokinetic hormone (Drome-AKH) (Schaffer et al, 1990), and was previously named Glomo-AKH II, Phote-HrTH or GmmHrTH in tsetse flies (Kaufmann et al, 2009;Attardo et al, 2012;Caers et al, 2015). Here we designate AKH neuropeptides in G. m. morsitans as Glomo-AKH I and Glomo-AKH II, which are encoded by gmmakh and gmmhrth genes, respectively (Kaufmann et al, 2009;Attardo et al, 2012).…”