Structure-Activity Relationships of FMRFamide-Related Peptides Contracting Schistosoma mansoni Muscle

Day, Tim A.; Maule, Aaron G.; Shaw, Chris; Pax, Ralph A.

doi:10.1016/s0196-9781(97)00073-9

Cited by 34 publications

(35 citation statements)

References 21 publications

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“…They are involved in the feeding response of the mollusk Aplysia (Hurwitz et al 2000). RFamides are furthermore involved in regulation of muscle contraction of Schistosoma (Day et al 1997), crayfish (Quigley and Mercier 1997), and leech (O'Gara et al 1999), and have been shown to effect movement of the rat tail and porcine intestines, respectively (Kanetoh et al 2003;Decker et al 1997). For planulae of H. echinata as well as for the cubomedusa Tripedalia cystophora, RFamide has been shown experimentally to modulate phototaxis by inhibitory myomodulating activity (Plickert and Schneider 2004).…”

Section: Discussionmentioning

confidence: 99%

Neuronal cell death during metamorphosis of Hydractina echinata (Cnidaria, Hydrozoa)

et al. 2010

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In planula larvae of the invertebrate Hydractinia echinata (Cnidaria, Hydrozoa), peptides of the GLWamide and the RFamide families are expressed in distinct subpopulations of neurons, distributed in a typical spatial pattern through the larval body. However, in the adult polyp GLWamide or RFamide-expressing cells are located at body parts that do not correspond to the prior larval regions. Since we had shown previously that during metamorphosis a large number of cells are removed by programmed cell death (PCD), we aimed to analyze whether cells of the neuropeptide-expressing larval nerve net are among those sacrificed. By immunohistochemical staining and in situ hybridization, we labeled GLWamide- and RFamide-expressing cells. Double staining of neuropeptides and degraded DNA (TUNEL analysis) identified some neurosensory cells as being apoptotic. Derangement of the cytoplasm and rapid destruction of neuropeptide precursor RNA indicated complete death of these particular sensory cells in the course of metamorphosis. Additionally, a small group of RFamide-positive sensory cells in the developing mouth region of the primary polyp could be shown to emerge by proliferation. Our results support the idea that during metamorphosis, specific parts of the larval neuronal network are subject to neurodegeneration and therefore not used for construction of the adult nerve net. Most neuronal cells of the primary polyp arise by de novo differentiation of stem cells commited to neural differentiation in embryogenesis. At least some nerve cells derive from proliferation of progenitor cells. Clarification of how the nerve net of these basal eumetazoans degenerates may add information to the understanding of neurodegeneration by apoptosis as a whole in the animal kingdom.

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Section: Discussionmentioning

confidence: 99%

Neuronal cell death during metamorphosis of Hydractina echinata (Cnidaria, Hydrozoa)

et al. 2010

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“…A very comprehensive structure-activity study of the excitatory action of FLPs on trematode isolated muscle fibres was undertaken by Day et al (1997). The three turbellarian FLPs, viz, GYIRFa, YIRFa and RYIRFa were active with EC 50 s of 1-7 nM while the cestode FLP, GNFFRFa, had an EC 50 of 0.5 lM.…”

Section: Platyhelminthsmentioning

confidence: 99%

A review of FMRFamide- and RFamide-like peptides in metazoa

2009

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Neuropeptides are a diverse class of signalling molecules that are widely employed as neurotransmitters and neuromodulators in animals, both invertebrate and vertebrate. However, despite their fundamental importance to animal physiology and behaviour, they are much less well understood than the small molecule neurotransmitters. The neuropeptides are classified into families according to similarities in their peptide sequence; and on this basis, the FMRFamide and RFamide-like peptides, first discovered in molluscs, are an example of a family that is conserved throughout the animal phyla. In this review, the literature on these neuropeptides has been consolidated with a particular emphasis on allowing a comparison between data sets in phyla as diverse as coelenterates and mammals. The intention is that this focus on the structure and functional aspects of FMRFamide and RFamide-like neuropeptides will inform understanding of conserved principles and distinct properties of signalling across the animal phyla.

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“…In order to examine GFVRIamide’s function in greater detail, we performed two further experiments: (i) Exogenous application of GFVRIamide to whole adult schistosomes; (ii) RNAi of Sm-npp-1 . In adult worm pairs GFVRIamide reduced motile behaviour at 10 −5 M. At the same concentration the positive control peptide, YIRFamide, exhibited a similar magnitude of inhibition, an effect which was surprising given YIRFamide’s potent myoexcitatory effect on individual muscle cells (Day et al, 1997). However, reduced mobility could be a consequence of spastic (excitatory) or flaccid (muscular relaxation) paralyses, both of which were observed during these assays, with a mixture of corkscrewing, curling and waving, but also straightening behaviours (data not shown).…”

Section: Discussionmentioning

confidence: 98%

“…The potent activity of FLPs on dispersed schistosome muscle fibres indicates the occurrence of a muscle-based FLP receptor with appeal as a drug target candidate. Further, this receptor’s candidature as a drug target is enhanced by its promiscuity, in that it is also activated by FLPs of nematode and arthropod origin (Day et al, 1994, 1997; Graham et al, 1997, 2000; Marks et al, 1997; Moneypenny et al, 1997, 2001; Mousley et al, 2004). A FLP-responsive G-protein coupled receptor (GPCR) exists in the turbellarian, Girardia tigrina (Omar et al, 2007), but the site of expression, and thus potential role in muscle contraction, is unknown.…”

Section: Introductionmentioning

confidence: 99%

Schistosome I/Lamides – A new family of bioactive helminth neuropeptides

McVeigh

Mair

Novozhilova

et al. 2011

International Journal for Parasitology

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Here we report the identification of a new family of helminth neuropeptides with members in both nematodes and flatworms, and include preliminary cell biological and functional characterisation of one of the peptides from the trematode parasite of humans, Schistosoma mansoni. Bioinformatics and Rapid Amplification of cDNA Ends (RACE)-PCR were used to identify the complete S. mansoni neuropeptide precursor gene Sm-npp-1, which encodes three pentapeptides bearing the motif (A/G)FVR(I/L).NH2. Similar peptides were identified in three other flatworm species and in 15 nematode species. Quantitative PCR (qPCR) and immunocytochemical (ICC) analyses showed that Sm-npp-1 is constitutively expressed in larval and adult worms. ICC and confocal microscopy were employed to localise one of the schistosome NPP-1 peptides (GFVRIamide) in adult worms and schistosomules; antibodies labelled a pair of neurones in the cerebral ganglia that extend posteriorly along the main nerve cords. GFVRIamide displayed no detectable co-localisation with FMRFamide-like peptides (FLPs), nor was it detectable in muscle innervation. Exogenously applied peptide had a significant inhibitory effect on the mobility of whole adult worm pairs at 10−5 M (n=9). Finally, we explored Sm-npp-1 function in schistosomules using RNA interference (RNAi); we successfully achieved specific knockdown of the Sm-npp-1 transcript (54.46±10.41 % knockdown, n=3), but did not detect any clear, aberrant mobility or morphological phenotypes. NPP-1-like peptides are a new family of helminth peptides with a cell-specific expression pattern distinct from FLPs and a modulatory effect on schistosome muscular activity.

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Structure-Activity Relationships of FMRFamide-Related Peptides Contracting Schistosoma mansoni Muscle

Cited by 34 publications

References 21 publications

Neuronal cell death during metamorphosis of Hydractina echinata (Cnidaria, Hydrozoa)

Neuronal cell death during metamorphosis of Hydractina echinata (Cnidaria, Hydrozoa)

A review of FMRFamide- and RFamide-like peptides in metazoa

Schistosome I/Lamides – A new family of bioactive helminth neuropeptides

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