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2.
ACS Chem Neurosci ; 12(19): 3662-3671, 2021 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-34523332

RESUMO

Nicotinic acetylcholine receptors (nAChRs) are essential pentameric ligand-gated ion channels that are distributed throughout the central and peripheral nervous systems and non-neuronal tissues in mammalian species that play critical roles in a variety of neural and mental activities. The α3ß2 nAChR subtype participates in pain, addiction to nicotine, and other neurophysiological and pathological activities. Owing to the lack of highly selective pharmacological tools targeting α3ß2, related research on its tissue distribution and function has been hindered. α-Conotoxin (α-CTx) LtIA, discovered from Conus literatus in our lab, potently and selectively blocks α3ß2 nAChR, providing an important molecular probe to study the α3ß2 nAChR structure and function. We used the fluorescent molecule 5-carboxytetramethylrhodamine succinimidyl ester, which can react with the N-terminus of LtIA, to obtain a novel fluorescent analogue of LtIA (LtIA-F). The potency and selectivity of LtIA-F were tested using a two-electrode voltage clamp recording on various nAChRs expressed in Xenopus laevis oocytes. LtIA-F potently inhibited ACh-evoked currents at the α3ß2 nAChR, with an IC50 value of 90.66 nM, displaying a ∼4-fold decrease in potency compared with native LtIA without a change in selectivity. The serum stability results indicated that LtIA-F exhibited stability similar to that of native LtIA. This study on an α-CTx LtIA fluorescent analogue provides a wealth of pharmacological tools to explore the structure-function relationship, distribution, and ligand binding domain of the α3ß2 nAChR subtype.


Assuntos
Conotoxinas , Caramujo Conus , Receptores Nicotínicos , Animais , Conotoxinas/farmacologia
3.
Proc Biol Sci ; 288(1954): 20211017, 2021 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-34229491

RESUMO

Marine gastropods of the genus Conus are renowned for their remarkable diversity and deadly venoms. While Conus venoms are increasingly well studied for their biomedical applications, we know surprisingly little about venom composition in other lineages of Conidae. We performed comprehensive venom transcriptomic profiling for Conasprella coriolisi and Pygmaeconus traillii, first time for both respective genera. We complemented reference-based transcriptome annotation by a de novo toxin prediction guided by phylogeny, which involved transcriptomic data on two additional 'divergent' cone snail lineages, Profundiconus, and Californiconus. We identified toxin clusters (SSCs) shared among all or some of the four analysed genera based on the identity of the signal region-a molecular tag present in toxins. In total, 116 and 98 putative toxins represent 29 and 28 toxin gene superfamilies in Conasprella and Pygmaeconus, respectively; about quarter of these only found by semi-manual annotation of the SSCs. Two rare gene superfamilies, originally identified from fish-hunting cone snails, were detected outside Conus rather unexpectedly, so we further investigated their distribution across Conidae radiation. We demonstrate that both these, in fact, are ubiquitous in Conidae, sometimes with extremely high expression. Our findings demonstrate how a phylogeny-aware approach circumvents methodological caveats of similarity-based transcriptome annotation.


Assuntos
Conotoxinas , Caramujo Conus , Animais , Caramujo Conus/genética , Filogenia , Caramujos , Peçonhas
4.
Chemosphere ; 280: 130801, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34162122

RESUMO

The development of active transition-metal oxide (TMO) catalysts for the abatement of volatile organic compounds (VOCs) remains a great challenge. Controllable synthesis of TMOs with specific morphology and suitable composition is a promising way for acquiring efficient oxidation catalysts. Herein, a series of hierarchical Co3O4/CoNi-layered double oxides (CoNi-LDO) nanocages covered by interlaced nanosheets were synthesized using a cobalt metal-organic framework (Co-MOF)-based strategy. The textural properties, morphology, surface chemical state, and reducibility of the CoNi-LDO catalysts were systematically characterized by various techniques. The catalytic activity toward toluene oxidation and the stability performance was investigated. Results demonstrated that the morphology, composition, and textual properties can be controlled by tuning the post-synthetic etching reaction conditions. Benefiting from the structural and compositional merits, as well as the superior low-temperature reducibility, the CoNi-LDO-1 catalyst (Ni/Co molar ratio was 0.39) with core-shell structure exhibited excellent activity toward toluene oxidation. Our work offers a new strategy for the design of high-performance oxidation catalysts for the abatement of VOCs.


Assuntos
Caramujo Conus , Estruturas Metalorgânicas , Animais , Catálise , Óxidos , Tolueno
5.
Sci Rep ; 11(1): 13282, 2021 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-34168165

RESUMO

The venom duct origins of predatory and defensive venoms has not been studied for hook-and-line fish hunting cone snails despite the pharmacological importance of their venoms. To better understand the biochemistry and evolution of injected predatory and defensive venoms, we compared distal, central and proximal venom duct sections across three specimens of C. striatus (Pionoconus) using proteomic and transcriptomic approaches. A total of 370 conotoxin precursors were identified from the whole venom duct transcriptome. Milked defensive venom was enriched with a potent cocktail of proximally expressed inhibitory α-, ω- and µ-conotoxins compared to milked predatory venom. In contrast, excitatory κA-conotoxins dominated both the predatory and defensive venoms despite their distal expression, suggesting this class of conotoxin can be selectively expressed from the same duct segment in response to either a predatory or defensive stimuli. Given the high abundance of κA-conotoxins in the Pionoconus clade, we hypothesise that the κA-conotoxins have evolved through adaptive evolution following their repurposing from ancestral inhibitory A superfamily conotoxins to facilitate the dietary shift to fish hunting and species radiation in this clade.


Assuntos
Conotoxinas/metabolismo , Caramujo Conus/metabolismo , Animais , Evolução Biológica , Conotoxinas/genética , Caramujo Conus/anatomia & histologia , Caramujo Conus/fisiologia , Perfilação da Expressão Gênica , Comportamento Predatório , Proteômica , Alinhamento de Sequência , Transcriptoma/genética
6.
Biochem Pharmacol ; 190: 114638, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34062129

RESUMO

The short disulfide-rich α-conotoxins derived from the venom of Conus snails comprise a conserved CICII(m)CIII(n)CIV cysteine framework (m and n, number of amino acids) and the majority antagonize nicotinic acetylcholine receptors (nAChRs). Depending on disulfide connectivity, α-conotoxins can exist as either globular (CI-CIII, CII-CIV), ribbon (CI-CIV, CII-CIII) or bead (CI-CII, CIII-CIV) isomers. In the present study, C. geographus α-conotoxins GI, GIB, G1.5 and G1.9 were chemically synthesized as globular and ribbon isomers and their activity investigated at human nAChRs expressed in Xenopus oocytes using the two-electrode voltage clamp recording technique. Both the globular and ribbon isomers of the 3/5 (m/n) α-conotoxins GI and GIB selectively inhibit heterologous human muscle-type α1ß1δε nAChRs, whereas G1.5, a 4/7 α-conotoxin, selectively antagonizes neuronal (non-muscle) nAChR subtypes particularly human α3ß2, α7 and α9α10 nAChRs. In contrast, globular and ribbon isomers of G1.9, a novel C-terminal elongated 4/8 α-conotoxin exhibited no activity at the human nAChR subtypes studied. This study reinforces earlier observations that 3/5 α-conotoxins selectively target the muscle nAChR subtypes, although interestingly, GIB is also active at α7 and α9 α10 nAChRs. The 4/7 α-conotoxins target human neuronal nAChR subtypes whereas the pharmacology of the 4/8 α-conotoxin remains unknown.


Assuntos
Conotoxinas/química , Conotoxinas/farmacologia , Caramujo Conus/fisiologia , Antagonistas Nicotínicos/farmacologia , Receptores Nicotínicos/metabolismo , Animais , Humanos , Antagonistas Nicotínicos/química , Oócitos , Técnicas de Patch-Clamp , Isoformas de Proteínas , Subunidades Proteicas , Xenopus laevis/metabolismo
7.
J Neurochem ; 159(1): 90-100, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34008858

RESUMO

α-Conotoxins are small disulfide-rich peptides found in the venom of marine cone snails and are potent antagonists of nicotinic acetylcholine receptors (nAChRs). They are valuable pharmacological tools and have potential therapeutic applications for the treatment of chronic pain or neurological diseases and disorders. In the present study, we synthesized and functionally characterized a novel α-conotoxin Bt1.8, which was cloned from Conus betulinus. Bt1.8 selectively inhibited ACh-evoked currents in Xenopus oocytes expressing rat(r) α6/α3ß2ß3 and rα3ß2 nAChRs with an IC50 of 2.1 nM and 9.4 nM, respectively, and similar potency for human (h) α6/α3ß2ß3 and hα3ß2 nAChRs. Additionally, Bt1.8 had higher binding affinity with a slower dissociation rate for the rα6/α3ß2ß3 subtype compared to rα3ß2. The amino acid sequence of Bt1.8 is significantly different from other reported α-conotoxins targeting the two nAChR subtypes. Further Alanine scanning analyses demonstrated that residues Ile9, Leu10, Asn11, Asn12 and Asn14 are critical for its inhibitory activity at the α6/α3ß2ß3 and α3ß2 subtypes. Moreover, the NMR structure of Bt1.8 indicated the presence of a relatively larger hydrophobic zone than other α4/7-conotoxins which may explain its potent inhibition at α6/α3ß2ß3 nAChRs.


Assuntos
Conotoxinas/farmacologia , Antagonistas Nicotínicos/farmacologia , Receptores Nicotínicos/metabolismo , Animais , Conotoxinas/química , Conotoxinas/isolamento & purificação , Caramujo Conus , Relação Dose-Resposta a Droga , Feminino , Humanos , Antagonistas Nicotínicos/química , Antagonistas Nicotínicos/isolamento & purificação , Oócitos , Estrutura Terciária de Proteína , Subunidades Proteicas/antagonistas & inibidores , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Ratos , Receptores Nicotínicos/genética , Xenopus laevis
8.
Asian Pac J Cancer Prev ; 22(5): 1523-1529, 2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-34048181

RESUMO

BACKGROUND: Marine animals have been considered by many researchers due to their various pharmacological effects. One group of marine animals that have been studied is cone snails. The conotoxin obtained from these marine animals has various therapeutic effects. METHODS: This study was designed to investigate the apoptotic effects of crude venom of Conus textile and its fractions (A and B) on chronic lymphocytic leukemia (CLL) cells. Accordingly, parameters such as cell viability, reactive oxygen species (ROS) level, collapse in mitochondrial membrane potential (MMP), lysosomal membrane damage and caspase-3 activation were evaluated. RESULTS: The results showed that the crude venom (50, 100 and 200 µg/ml) from Conus textile and its fraction B (50, 100 and 200 µg/ml) significantly reduced viability in CLL B-lymphocyte. In addition, exposure of CLL B-lymphocyte to fraction B (50, 100 and 200 µg/ml) was associated with an increase in the level of ROS, the collapse of the MMP, damage to the lysosomal membrane, and activation of caspase-3. CONCLUSION: According to results, it was concluded that fraction B from crude venom of Conus textile causes selective toxicity on CLL B-lymphocyte with almost no effect on a normal lymphocyte. Furthermore, this venom fraction could be a promising candidate for induction of apoptosis in patients with CLL through the mitochondrial pathway.


Assuntos
Caspase 3/metabolismo , Caramujo Conus/química , Leucemia Linfocítica Crônica de Células B/patologia , Linfócitos/patologia , Mitocôndrias/efeitos dos fármacos , Peçonhas/farmacologia , Animais , Apoptose , Sobrevivência Celular , Células Cultivadas , Humanos , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Linfocítica Crônica de Células B/metabolismo , Linfócitos/efeitos dos fármacos , Potencial da Membrana Mitocondrial , Espécies Reativas de Oxigênio/metabolismo
9.
J Med Chem ; 64(10): 7033-7043, 2021 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-33949869

RESUMO

In a program to identify pain treatments with low addiction potential, we isolated five steroids, conosteroids A-E (1-5), from the hypobranchial gland of the mollusk Conus geographus. Compounds 1-5 were active in a mouse dorsal root ganglion (DRG) assay that suggested that they might be analgesic. A synthetic analogue 6 was used for a detailed pharmacological study. Compound 6 significantly increased the pain threshold in mice in the hot-plate test at 2 and 50 mg/kg. Compound 6 at 500 nM antagonizes type-A γ-aminobutyric acid receptors (GABAARs). In a patch-clamp experiment, out of the six subunit combinations tested, 6 exhibited subtype selectivity, most strongly antagonizing α1ß1γ2 and α4ß3γ2 receptors (IC50 1.5 and 1.0 µM, respectively). Although the structures of 1-6 differ from those of known neuroactive steroids, they are cell-type-selective modulators of GABAARs, expanding the known chemical space of neuroactive steroids.


Assuntos
Analgésicos/química , Caramujo Conus/química , Antagonistas GABAérgicos/química , Neuroesteroides/química , Receptores de GABA/química , Potenciais de Ação/efeitos dos fármacos , Analgésicos/síntese química , Analgésicos/farmacologia , Analgésicos/uso terapêutico , Animais , Caramujo Conus/metabolismo , Modelos Animais de Doenças , Antagonistas GABAérgicos/isolamento & purificação , Antagonistas GABAérgicos/farmacologia , Antagonistas GABAérgicos/uso terapêutico , Gânglios Espinais/citologia , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Conformação Molecular , Neuroesteroides/isolamento & purificação , Neuroesteroides/farmacologia , Neuroesteroides/uso terapêutico , Dor/induzido quimicamente , Dor/tratamento farmacológico , Dor/patologia , Subunidades Proteicas/química , Subunidades Proteicas/metabolismo , Receptores de GABA/metabolismo
10.
Mult Scler Relat Disord ; 52: 103017, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34023773

RESUMO

Myelin oligodendrocyte glycoprotein antibody-associated disorder (MOGAD) is a central nervous system inflammatory disorder associated with MOG antibodies. Two patients with clinical symptoms of cauda equina syndrome had positive serum MOG antibody tests, and spinal magnetic resonance imaging showed cauda equina enhancement. They were diagnosed with incomplete cauda equina syndrome associated with MOGAD. A few cases of lumbosacral radiculomyelitis associated with MOGAD have been reported; however, this is the first report of isolated lumbosacral radiculitis associated with MOGAD without transverse myelitis. The MOG antibody test should be considered for cauda equina syndrome without compressive lesions.


Assuntos
Síndrome da Cauda Equina , Caramujo Conus , Mielite Transversa , Animais , Autoanticorpos , Humanos , Glicoproteína Mielina-Oligodendrócito
11.
Gigascience ; 10(5)2021 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-34037232

RESUMO

BACKGROUND: Venoms are deadly weapons to subdue prey or deter predators that have evolved independently in many animal lineages. The genomes of venomous animals are essential to understand the evolutionary mechanisms involved in the origin and diversification of venoms. RESULTS: Here, we report the chromosome-level genome of the venomous Mediterranean cone snail, Lautoconus ventricosus (Caenogastropoda: Conidae). The total size of the assembly is 3.59 Gb; it has high contiguity (N50 = 93.53 Mb) and 86.6 Mb of the genome assembled into the 35 largest scaffolds or pseudochromosomes. On the basis of venom gland transcriptomes, we annotated 262 complete genes encoding conotoxin precursors, hormones, and other venom-related proteins. These genes were scattered in the different pseudochromosomes and located within repetitive regions. The genes encoding conotoxin precursors were normally structured into 3 exons, which did not necessarily coincide with the 3 structural domains of the corresponding proteins. Additionally, we found evidence in the L. ventricosus genome for a past whole-genome duplication event by means of conserved gene synteny with the Pomacea canaliculata genome, the only one available at the chromosome level within Caenogastropoda. The whole-genome duplication event was further confirmed by the presence of a duplicated hox gene cluster. Key genes for gastropod biology including those encoding proteins related to development, shell formation, and sex were located in the genome. CONCLUSIONS: The new high-quality L. ventricosus genome should become a reference for assembling and analyzing new gastropod genomes and will contribute to future evolutionary genomic studies among venomous animals.


Assuntos
Conotoxinas , Caramujo Conus , Animais , Caramujo Conus/genética , Genoma , Caramujos/genética , Peçonhas
12.
Mult Scler Relat Disord ; 52: 103011, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34015641

RESUMO

There are a variety of clinical phenotypes and radiological features that continue to make a diagnosis of neuromyelitis optica spectrum disorder (NMOSD) challenging. We present an atypical case of an adult woman who presented with flaccid paralysis of all extremities with unusual neuroimaging features, including extensive enhancing lesions in the upper cervical cord and conus medullaris with associated leptomeningeal enhancement. She was ultimately found to have AQP4 antibody-positive NMOSD. We discuss the factors that complicated a timely diagnosis, including her atypical radiographic features and an initially negative cell-based assay for myelin oligodendrocyte glycoprotein (MOG) and aquaporin-4 (AQP4) antibodies. Despite the rarity of conus medullaris involvement or leptomeningeal enhancement in AQP4 antibody-positive NMOSD, it is important to maintain a high level of clinical suspicion to avoid diagnostic and therapeutic delays. Though cell-based assays have high sensitivities, testing should be repeated on negative values in these scenarios.


Assuntos
Caramujo Conus , Neuromielite Óptica , Adulto , Animais , Aquaporina 4 , Autoanticorpos , Feminino , Humanos , Glicoproteína Mielina-Oligodendrócito
13.
Biochemistry ; 60(16): 1299-1311, 2021 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-33829763

RESUMO

The tetrapeptides Li504 and Li520, differing in the modification of the 4-trans-hydroxylation of proline, are novel conopeptides derived from the venom duct transcriptome of the marine cone snail Conus lividus. These predicted mature peptides are homologous to the active site motif of oxidoreductases that catalyze the oxidation, reduction, and rearrangement of disulfide bonds in peptides and proteins. The estimated reduction potential of the disulfide of Li504 and Li520 is within the range of disulfide reduction potentials of oxidoreductases, indicating that they may catalyze the oxidative folding of conotoxins. Conformational features of Li504 and Li520 include the trans configuration of the Cys1-Pro2/Hyp2 peptide bond with a type 1 turn that is similar to the active site motif of glutaredoxin that regulates the oxidation of cysteine thiols to disulfides. Li504- and Li520-assisted oxidative folding of α-conotoxin ImI confirms that Li520 improves the yield of the natively folded peptide by concomitantly decreasing the yield of the non-native disulfide isomer and thus acts as a miniature disulfide isomerase. The geometry of the Cys1-Hyp2 peptide bond of Li520 shifts between the trans and cis configurations in the disulfide form and thiol/thiolate form, which regulates the deprotonation of the N-terminal cysteine residue. Hydrogen bonding of the hydroxyl group of 4-trans-hydroxyproline with the interpeptide chain unit in the mixed disulfide form may play a vital role in shifting the geometry of the Cys1-Hyp2 peptide bond from cis to trans configuration. The Li520 conopeptide together with similar peptides derived from other species may constitute a new family of "redox-active" conopeptides that are integral components of the oxidative folding machinery of conotoxins.


Assuntos
Conotoxinas/química , Caramujo Conus/genética , Oligopeptídeos/farmacologia , Dobramento de Proteína/efeitos dos fármacos , Transcriptoma , Peçonhas/genética , Animais , Oligopeptídeos/química , Oxirredução , Estereoisomerismo
14.
Mar Drugs ; 19(3)2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33801301

RESUMO

Cone snails are venomous marine predators that rely on fast-acting venom to subdue their prey and defend against aggressors. The conotoxins produced in the venom gland are small disulfide-rich peptides with high affinity and selectivity for their pharmacological targets. A dominant group comprises α-conotoxins, targeting nicotinic acetylcholine receptors. Here, we report on the synthesis, structure determination and biological activity of a novel α-conotoxin, CIC, found in the predatory venom of the piscivorous species Conus catus and its truncated mutant Δ-CIC. CIC is a 4/7 α-conotoxin with an unusual extended N-terminal tail. High-resolution NMR spectroscopy shows a major influence of the N-terminal tail on the apparent rigidity of the three-dimensional structure of CIC compared to the more flexible Δ-CIC. Surprisingly, this effect on the structure does not alter the biological activity, since both peptides selectively inhibit α3ß2 and α6/α3ß2ß3 nAChRs with almost identical sub- to low micromolar inhibition constants. Our results suggest that the N-terminal part of α-conotoxins can accommodate chemical modifications without affecting their pharmacology.


Assuntos
Conotoxinas/isolamento & purificação , Caramujo Conus/metabolismo , Venenos de Moluscos/química , Antagonistas Nicotínicos/isolamento & purificação , Animais , Conotoxinas/química , Conotoxinas/farmacologia , Espectroscopia de Ressonância Magnética , Antagonistas Nicotínicos/farmacologia , Receptores Nicotínicos/efeitos dos fármacos , Receptores Nicotínicos/metabolismo
15.
Mar Drugs ; 19(4)2021 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-33916793

RESUMO

Marine cone snails are predatory gastropods characterized by a well-developed venom apparatus and highly evolved hunting strategies that utilize toxins to paralyze prey and defend against predators. The venom of each species of cone snail has a large number of pharmacologically active peptides known as conopeptides or conotoxins that are usually unique in each species. Nevertheless, venoms of only very few species have been characterized so far by transcriptomic approaches. In this study, we used transcriptome sequencing technologies and mass spectrometric methods to describe the diversity of venom components expressed by a worm-hunting species, Conus bayani. A total of 82 conotoxin sequences were retrieved from transcriptomic data that contain 54 validated conotoxin sequences clustered into 21 gene superfamilies including divergent gene family, 17 sequences clustered to 6 different conotoxin classes, and 11 conotoxins classified as unassigned gene family. Seven new conotoxin sequences showed unusual cysteine patterns. We were also able to identify 19 peptide sequences using mass spectrometry that completely overlapped with the conotoxin sequences obtained from transcriptome analysis. Importantly, herein we document the presence of 16 proteins that include five post-translational modifying enzymes obtained from transcriptomic data. Our results revealed diverse and novel conopeptides of an unexplored species that could be used extensively in biomedical research due to their therapeutic potentials.


Assuntos
Conotoxinas/genética , Caramujo Conus/genética , Enzimas/genética , Perfilação da Expressão Gênica , Venenos de Moluscos/genética , Peptídeos/genética , Proteômica , Animais , Conotoxinas/metabolismo , Caramujo Conus/enzimologia , Bases de Dados Genéticas , Enzimas/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala , Espectrometria de Massas , Venenos de Moluscos/enzimologia , Peptídeos/metabolismo , Proteoma , Transcriptoma
16.
J Med Chem ; 64(6): 3222-3233, 2021 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-33724033

RESUMO

Several Conus-derived venom peptides are promising lead compounds for the management of neuropathic pain, with α-conotoxins being of particular interest. Modification of the interlocked disulfide framework of α-conotoxin Vc1.1 has been achieved using on-resin alkyne metathesis. Although introduction of a metabolically stable alkyne motif significantly disrupts backbone topography, the structural modification generates a potent and selective GABAB receptor agonist that inhibits Cav2.2 channels and exhibits dose-dependent reversal of mechanical allodynia in a behavioral rat model of neuropathic pain. The findings herein support the hypothesis that analgesia can be achieved via activation of GABABRs expressed in dorsal root ganglion (DRG) sensory neurons.


Assuntos
Alcinos/uso terapêutico , Analgésicos/uso terapêutico , Conotoxinas/uso terapêutico , Hiperalgesia/tratamento farmacológico , Neuralgia/tratamento farmacológico , Alcinos/química , Analgésicos/química , Animais , Células Cultivadas , Conotoxinas/química , Caramujo Conus/química , Modelos Animais de Doenças , Feminino , Células HEK293 , Humanos , Hiperalgesia/fisiopatologia , Masculino , Modelos Moleculares , Neuralgia/fisiopatologia , Ratos Sprague-Dawley , Xenopus
17.
Pharmacol Biochem Behav ; 205: 173182, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33774007

RESUMO

Cannabinoid (CB) receptor agonists show robust antinociceptive effects in various pain models. However, most of the clinically potent CB1 receptor-active drugs derived from cannabis are considered concerning due to psychotomimetic side effects. Selective CB receptor ligands that do not induce CNS side effects are of clinical interest. The venoms of marine snail Conus are a natural source of various potent analgesic peptides, some of which are already FDA approved. In this study we evaluated the ability of several Conus venom extracts to interact with CB1 receptor. HEK293 cells expressing CB1 receptors were treated with venom extracts and CB1 receptor internalization was analyzed by immunofluorescence. Results showed C. textile (C. Tex) and C. miles (C. Mil) samples as the most potent. These were serially subfractionated by HPLC for subsequent analysis by internalization assays and for analgesic potency evaluated in the formalin test and after peripheral nerve injury. Intrathecal injection of C. Tex and C. Mil subfractions reduced flinching/licking behavior during the second phase of formalin test and attenuated thermal and mechanical allodynia in nerve injury model. Treatment with proteolytic enzymes reduced CB1 internalization of subfractions, indicating the peptidergic nature of CB1 active component. Further HPLC purification revealed two potent antinociceptive subfractions within C. Tex with CB1 and possible CB2 activity, with mild to no side effects in the CB tetrad assessment. CB conopeptides can be isolated from these active Conus venom-derived samples and further developed as novel analgesic agents for the treatment of chronic pain using cell based or gene therapy approaches.


Assuntos
Agonistas de Receptores de Canabinoides/farmacologia , Dor Crônica/tratamento farmacológico , Venenos de Moluscos/farmacologia , Analgésicos/farmacologia , Animais , Comportamento Animal/efeitos dos fármacos , Agonistas de Receptores de Canabinoides/administração & dosagem , Canabinoides/farmacologia , Dor Crônica/metabolismo , Caramujo Conus/química , Terapia Genética/métodos , Células HEK293 , Humanos , Hiperalgesia/tratamento farmacológico , Hiperalgesia/metabolismo , Injeções Espinhais , Venenos de Moluscos/administração & dosagem , Medição da Dor/efeitos dos fármacos , Doenças do Sistema Nervoso Periférico/tratamento farmacológico , Doenças do Sistema Nervoso Periférico/metabolismo , Ratos , Receptor CB1 de Canabinoide/metabolismo , Receptor CB2 de Canabinoide/metabolismo
18.
Mar Drugs ; 19(2)2021 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-33530397

RESUMO

Conotoxins are disulfide-rich peptides found in the venom of cone snails. Due to their exquisite potency and high selectivity for a wide range of voltage and ligand gated ion channels they are attractive drug leads in neuropharmacology. Recently, cone snails were found to have the capability to rapidly switch between venom types with different proteome profiles in response to predatory or defensive stimuli. A novel conotoxin, GXIA (original name G117), belonging to the I3-subfamily was identified as the major component of the predatory venom of piscivorous Conus geographus. Using 2D solution NMR spectroscopy techniques, we resolved the 3D structure for GXIA, the first structure reported for the I3-subfamily and framework XI family. The 32 amino acid peptide is comprised of eight cysteine residues with the resultant disulfide connectivity forming an ICK+1 motif. With a triple stranded ß-sheet, the GXIA backbone shows striking similarity to several tarantula toxins targeting the voltage sensor of voltage gated potassium and sodium channels. Supported by an amphipathic surface, the structural evidence suggests that GXIA is able to embed in the membrane and bind to the voltage sensor domain of a putative ion channel target.


Assuntos
Espectroscopia de Ressonância Magnética/métodos , Neurotoxinas/análise , Neurotoxinas/síntese química , ômega-Conotoxina GVIA/análise , ômega-Conotoxina GVIA/síntese química , Sequência de Aminoácidos , Animais , Conotoxinas/análise , Conotoxinas/síntese química , Conotoxinas/genética , Caramujo Conus , Neurotoxinas/genética , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , ômega-Conotoxina GVIA/genética
19.
Toxicon ; 194: 70-78, 2021 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-33610632

RESUMO

Cone snails are predatory gastropod mollusks that are distributed in all tropical marine environments and contain small peptides (conotoxins) in their venom to capture prey. However, the biochemical and molecular aspects of conotoxins remain poorly understood. In this article, a novel α4/7-conotoxin, Lv1d, was obtained from the venom duct cDNA library of the worm-hunting Conus lividus collected from the South China Sea. The cDNA of Lv1c encodes a 65 residue conopeptide precursor, which consists of a 21 residue signal peptide, a 27 residue Pro region, and 17 residues of mature peptide. The mature peptide Lv1d was chemically synthesized according to the sequence GCCSDPPCRHKHQDLCG. It was found that 10 µM Lv1d can completely inhibit frog sciatic nerve-gastrocnemius muscle contractility within 60 min. Moreover, 100 µg/kg Lv1d showed good analgesic effects in mouse hot plate model and formalin test. Patch clamp experiments showed that 5 µM Lv1d can inhibit the cholinergic microexcitatory postsynaptic currents (mEPSCs) requency and amplitude of projection neurons in Drosophila. In conclusion, the synthesis of Lv1d and its biological and physiological data might contribute to the development of this peptide as a novel potential drug for therapeutic applications. This finding also expands the knowledge of the targeting mechanism of the α4/7-subfamily conotoxins.


Assuntos
Conotoxinas , Caramujo Conus , Sequência de Aminoácidos , Analgésicos/farmacologia , Animais , China , Conotoxinas/farmacologia , Camundongos
20.
Childs Nerv Syst ; 37(6): 2025-2031, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33604718

RESUMO

OBJECTIVE: Lumbosacral lipomas (LSL) of the 'dorsal' type have been associated with more favourable outcomes compared with other conus region lipomas. We hypothesised that integrity of the conus on MRI underpins the improved prognosis in this subgroup of LSL patients. METHODS: The definition of 'dorsal lipomas' included lipomas with attachment to the conus, but where the conus could be delineated on MRI (Morota type 1) as reported by Morota et al. (J Neurosurg Pediatr 19:428-439, 2017). Additional inclusion criteria included asymptomatic status at presentation, age >3 years at follow-up, and neurological and urological evaluation at presentation and at last follow-up. Lipoma extent and conus level were recorded. Outcome measures were the need for untethering surgery and neuro-urological status at last follow-up. Urological outcomes were defined by continence and efficacy of bladder emptying. RESULTS: Twenty-six children were included (median age 8.7 years). Conus level was low (at or below L2) in 92%. Nine required untethering surgery: 5 prophylactic, 4 because of clinical deterioration. Twenty-five children were continent at last follow-up, one had stress incontinence, and none required catheterisation. One had persisting ankle weakness after surgery requiring orthotic support. CONCLUSIONS: In LSL of the conus, visualisation of the conus on MRI is associated with good urological and motor outcomes. The integrity of the conus appears to be a more important prognostic factor than anatomical level. An observational approach to this group of LSL patients does not appear to compromise outcomes. These findings support a selective approach to untethering surgery.


Assuntos
Caramujo Conus , Lipoma , Neoplasias da Medula Espinal , Neoplasias da Coluna Vertebral , Animais , Criança , Pré-Escolar , Humanos , Lactente , Lipoma/diagnóstico por imagem , Lipoma/cirurgia , Região Lombossacral/diagnóstico por imagem , Região Lombossacral/cirurgia , Imageamento por Ressonância Magnética , Neoplasias da Medula Espinal/diagnóstico por imagem , Neoplasias da Medula Espinal/cirurgia , Resultado do Tratamento
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