A Novel Inhibitor of α9α10 Nicotinic Acetylcholine Receptors from Conus vexillum Delineates a New Conotoxin Superfamily

Luo, Sulan; Christensen, Sean; Zhangsun, Dongting; Wu, Yong; Hu, Yuanyan; Zhu, Xiaopeng; Chhabra, Sandeep; Norton, Raymond S.; McIntosh, J. Michael

doi:10.1371/journal.pone.0054648

Cited by 50 publications

(45 citation statements)

References 67 publications

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“…Despite a weak correlation between gene superfamilies and pharmacological properties, some functional redundancy among members of a same superfamily exists (56). To date, 16 empirical gene superfamilies (designated as A, D, I1, I2, I3, J, L, M, O1, O2, O3, P, S, T, V, Y) have been annotated (57), plus 31 novel superfamilies have been discovered during the past two years (38,39,46,(57)(58)(59)(60).…”

Section: Significancementioning

confidence: 99%

Optimized deep-targeted proteotranscriptomic profiling reveals unexplored Conus toxin diversity and novel cysteine frameworks

Lavergne

Harliwong

Jones

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Cone snails are predatory marine gastropods characterized by a sophisticated venom apparatus responsible for the biosynthesis and delivery of complex mixtures of cysteine-rich toxin peptides. These conotoxins fold into small highly structured frameworks, allowing them to potently and selectively interact with heterologous ion channels and receptors. Approximately 2,000 toxins from an estimated number of >70,000 bioactive peptides have been identified in the genus Conus to date. Here, we describe a high-resolution interrogation of the transcriptomes (available at www.ddbj.nig.ac.jp) and proteomes of the diverse compartments of the Conus episcopatus venom apparatus. Using biochemical and bioinformatic tools, we found the highest number of conopeptides yet discovered in a single Conus specimen, with 3,305 novel precursor toxin sequences classified into 9 known superfamilies (A, I1, I2, M, O1, O2, S, T, Z), and identified 16 new superfamilies showing unique signal peptide signatures. We were also able to depict the largest population of venom peptides containing the pharmacologically active C-C-CC-C-C inhibitor cystine knot and CC-C-C motifs (168 and 44 toxins, respectively), as well as 208 new conotoxins displaying odd numbers of cysteine residues derived from known conotoxin motifs. Importantly, six novel cysteine-rich frameworks were revealed which may have novel pharmacology. Finally, analyses of codon usage bias and RNA-editing processes of the conotoxin transcripts demonstrate a specific conservation of the cysteine skeleton at the nucleic acid level and provide new insights about the origin of sequence hypervariablity in mature toxin regions.

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Section: Significancementioning

confidence: 99%

Optimized deep-targeted proteotranscriptomic profiling reveals unexplored Conus toxin diversity and novel cysteine frameworks

Lavergne

Harliwong

Jones

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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“…We have carried out a broad program to identify and develop peptides that target α9α10 nAChRs, and five diverse structural families of conotoxins that inhibit α9α10 receptors have been characterized (20)(21)(22)(23)(24)(25). Two α-conotoxins from cone snail venoms, Vc1.1 and RgIA, are particularly promising in terms of their analgesic properties and the prevention of neuropathology; however, as detailed in the Introduction, these peptides exhibited a striking decline in affinity for the human receptor compared with the rodent α9α10 nAChR.…”

Section: Resultsmentioning

confidence: 99%

Inhibition of α9α10 nicotinic acetylcholine receptors prevents chemotherapy-induced neuropathic pain

Romero

Christensen

Mannelli

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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134

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Opioids are first-line drugs for moderate to severe acute pain and cancer pain. However, these medications are associated with severe side effects, and whether they are efficacious in treatment of chronic nonmalignant pain remains controversial. Medications that act through alternative molecular mechanisms are critically needed. Antagonists of α9α10 nicotinic acetylcholine receptors (nAChRs) have been proposed as an important nonopioid mechanism based on studies demonstrating prevention of neuropathology after trauma-induced nerve injury. However, the key α9α10 ligands characterized to date are at least two orders of magnitude less potent on human vs. rodent nAChRs, limiting their translational application. Furthermore, an alternative proposal that these ligands achieve their beneficial effects by acting as agonists of GABA B receptors has caused confusion over whether blockade of α9α10 nAChRs is the fundamental underlying mechanism. To address these issues definitively, we developed RgIA4, a peptide that exhibits high potency for both human and rodent α9α10 nAChRs, and was at least 1,000-fold more selective for α9α10 nAChRs vs. all other molecular targets tested, including opioid and GABA B receptors. A daily s.c. dose of RgIA4 prevented chemotherapy-induced neuropathic pain in rats. In wild-type mice, oxaliplatin treatment produced cold allodynia that could be prevented by RgIA4. Additionally, in α9 KO mice, chemotherapy-induced development of cold allodynia was attenuated and the milder, temporary cold allodynia was not relieved by RgIA4. These findings establish blockade of α9-containing nAChRs as the basis for the efficacy of RgIA4, and that α9-containing nAChRs are a critical target for prevention of chronic cancer chemotherapyinduced neuropathic pain.pain | chemotherapy | alpha9 | nicotinic

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“…Precursor Mi041 had 18 cDNA reads, and the predicted mature peptide was identified with good MS/MS coverage, containing only 11 amino acid residues. This peptide was a member of the recently reported cysteine framework XXIV (C-CC-C) (18) and included three proline residues in the two loops despite its short sequence.…”

Section: Conotoxin Precursors Mature Peptides and Cysteinementioning

confidence: 99%

“…Conotoxins are currently divided into 24 cysteine frameworks, designated using Roman numerals, according to the arrangement of cysteines in the mature peptide region (17,18). The disulfide bond connectivities are usually important for the folding and activity of conotoxins, although they are not part of the definition of the cysteine frameworks.…”

mentioning

confidence: 99%

Transcriptomic Messiness in the Venom Duct of Conus miles Contributes to Conotoxin Diversity

Jin

Dutertre

Kaas

et al. 2013

Molecular & Cellular Proteomics

113

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Marine cone snails have developed sophisticated chemical strategies to capture prey and defend themselves against predators. Among the vast array of bioactive molecules in their venom, peptide components called conotoxins or conopeptides dominate, with many binding with high affinity and selectivity to a broad range of cellular targets, including receptors and transporters of the nervous system. Whereas the conopeptide gene precursor organization has a conserved topology, the peptides in the venom duct are highly processed. Indeed, deep sequencing transcriptomics has uncovered on average fewer than 100 toxin gene precursors per species, whereas advanced proteomics has revealed >10-fold greater diversity at the peptide level. In the present study, second-generation sequencing technologies coupled to highly sensitive mass spectrometry methods were applied to rapidly uncover the conopeptide diversity in the venom of a worm-hunting species, Conus miles. A total of 662 putative conopeptide encoded sequences were retrieved from transcriptomic data, comprising 48 validated conotoxin sequences that clustered into 10 gene superfamilies, including 3 novel superfamilies and a novel cysteine framework (C-C-C-CCC-C-C) identified at both transcript and peptide levels. A surprisingly large number of conopeptide gene sequences were expressed at low levels, including a series of single amino acid variants, as well as sequences containing deletions and frame and stop codon shifts. Some of the toxin variants generate alternative cleavage sites, interrupted or elongated cysteine frameworks, and highly variable isoforms within families that could be identified at the peptide level. Together with the variable peptide processing identified previously, background genetic and phenotypic levels of biological messiness in venoms contribute to the hypervariability of venom peptides and their ability to evolve rapidly. Molecular & Cellular Proteomics 12:

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A Novel Inhibitor of α9α10 Nicotinic Acetylcholine Receptors from Conus vexillum Delineates a New Conotoxin Superfamily

Cited by 50 publications

References 67 publications

Optimized deep-targeted proteotranscriptomic profiling reveals unexplored Conus toxin diversity and novel cysteine frameworks

Optimized deep-targeted proteotranscriptomic profiling reveals unexplored Conus toxin diversity and novel cysteine frameworks

Inhibition of α9α10 nicotinic acetylcholine receptors prevents chemotherapy-induced neuropathic pain

Transcriptomic Messiness in the Venom Duct of Conus miles Contributes to Conotoxin Diversity

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