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1.
Mol Biol Evol ; 41(8)2024 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-38935574

RESUMO

Venom systems are complex traits that have independently emerged multiple times in diverse plant and animal phyla. Within each venomous lineage there typically exists interspecific variation in venom composition where several factors have been proposed as drivers of variation, including phylogeny and diet. Understanding these factors is of broad biological interest and has implications for the development of antivenom therapies and venom-based drug discovery. Because of their high species richness and the presence of several major evolutionary prey shifts, venomous marine cone snails (genus Conus) provide an ideal system to investigate drivers of interspecific venom variation. Here, by analyzing the venom gland expression profiles of ∼3,000 toxin genes from 42 species of cone snail, we elucidate the role of prey-specific selection pressures in shaping venom variation. By analyzing overall venom composition and individual toxin structures, we demonstrate that the shifts from vermivory to piscivory in Conus are complemented by distinct changes in venom composition independent of phylogeny. In vivo injections of venom from piscivorous cone snails in fish further showed a higher potency compared with venom of nonpiscivores demonstrating a selective advantage. Together, our findings provide compelling evidence for the role of prey shifts in directing the venom composition of cone snails and expand our understanding of the mechanisms of venom variation and diversification.


Assuntos
Caramujo Conus , Venenos de Moluscos , Animais , Caramujo Conus/genética , Venenos de Moluscos/genética , Comportamento Predatório , Evolução Biológica , Filogenia , Evolução Molecular
2.
Mar Drugs ; 22(5)2024 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-38786593

RESUMO

α7 nicotinic acetylcholine receptors (nAChRs) are mainly distributed in the central nervous system (CNS), including the hippocampus, striatum, and cortex of the brain. The α7 nAChR has high Ca2+ permeability and can be quickly activated and desensitized, and is closely related to Alzheimer's disease (AD), epilepsy, schizophrenia, lung cancer, Parkinson's disease (PD), inflammation, and other diseases. α-conotoxins from marine cone snail venom are typically short, disulfide-rich neuropeptides targeting nAChRs and can distinguish various subtypes, providing vital pharmacological tools for the functional research of nAChRs. [Q1G, ΔR14]LvΙB is a rat α7 nAChRs selective antagonist, modified from α-conotoxin LvΙB. In this study, we utilized three types of fluorescein after N-Hydroxy succinimide (NHS) activation treatment: 6-TAMRA-SE, Cy3 NHS, and BODIPY-FL NHS, labeling the N-Terminal of [Q1G, ΔR14]LvΙB under weak alkaline conditions, obtaining three fluorescent analogs: LvIB-R, LvIB-C, and LvIB-B, respectively. The potency of [Q1G, ΔR14]LvΙB fluorescent analogs was evaluated at rat α7 nAChRs expressed in Xenopus laevis oocytes. Using a two-electrode voltage clamp (TEVC), the half-maximal inhibitory concentration (IC50) values of LvIB-R, LvIB-C, and LvIB-B were 643.3 nM, 298.0 nM, and 186.9 nM, respectively. The stability of cerebrospinal fluid analysis showed that after incubation for 12 h, the retention rates of the three fluorescent analogs were 52.2%, 22.1%, and 0%, respectively. [Q1G, ΔR14]LvΙB fluorescent analogs were applied to explore the distribution of α7 nAChRs in the hippocampus and striatum of rat brain tissue and it was found that Cy3- and BODIPY FL-labeled [Q1G, ΔR14]LvΙB exhibited better imaging characteristics than 6-TAMARA-. It was also found that α7 nAChRs are widely distributed in the cerebral cortex and cerebellar lobules. Taking into account potency, imaging, and stability, [Q1G, ΔR14]LvΙB -BODIPY FL is an ideal pharmacological tool to investigate the tissue distribution and function of α7 nAChRs. Our findings not only provide a foundation for the development of conotoxins as visual pharmacological probes, but also demonstrate the distribution of α7 nAChRs in the rat brain.


Assuntos
Encéfalo , Conotoxinas , Xenopus laevis , Receptor Nicotínico de Acetilcolina alfa7 , Animais , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Conotoxinas/farmacologia , Conotoxinas/química , Ratos , Encéfalo/metabolismo , Encéfalo/efeitos dos fármacos , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Antagonistas Nicotínicos/farmacologia , Corantes Fluorescentes , Ratos Sprague-Dawley , Masculino , Feminino
3.
Molecules ; 29(12)2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38930912

RESUMO

The escalating resistance of agricultural pests to chemical insecticides necessitates the development of novel, efficient, and safe biological insecticides. Conus quercinus, a vermivorous cone snail, yields a crude venom rich in peptides for marine worm predation. This study screened six α-conotoxins with insecticidal potential from a previously constructed transcriptome database of C. quercinus, characterized by two disulfide bonds. These conotoxins were derived via solid-phase peptide synthesis (SPPS) and folded using two-step iodine oxidation for further insecticidal activity validation, such as CCK-8 assay and insect bioassay. The final results confirmed the insecticidal activities of the six α-conotoxins, with Qc1.15 and Qc1.18 exhibiting high insecticidal activity. In addition, structural analysis via homology modeling and functional insights from molecular docking offer a preliminary look into their potential insecticidal mechanisms. In summary, this study provides essential references and foundations for developing novel insecticides.


Assuntos
Conotoxinas , Caramujo Conus , Inseticidas , Simulação de Acoplamento Molecular , Conotoxinas/química , Conotoxinas/farmacologia , Conotoxinas/síntese química , Inseticidas/química , Inseticidas/síntese química , Inseticidas/farmacologia , Animais , Caramujo Conus/química , Sequência de Aminoácidos , Peptídeos/química , Peptídeos/farmacologia , Peptídeos/síntese química , Técnicas de Síntese em Fase Sólida/métodos
4.
Mol Biol Evol ; 39(4)2022 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-35383850

RESUMO

Somatostatin and its related peptides (SSRPs) form an important family of hormones with diverse physiological roles. The ubiquitous presence of SSRPs in vertebrates and several invertebrate deuterostomes suggests an ancient origin of the SSRP signaling system. However, the existence of SSRP genes outside of deuterostomes has not been established, and the evolutionary history of this signaling system remains poorly understood. Our recent discovery of SSRP-like toxins (consomatins) in venomous marine cone snails (Conus) suggested the presence of a related signaling system in mollusks and potentially other protostomes. Here, we identify the molluscan SSRP-like signaling gene that gave rise to the consomatin family. Following recruitment into venom, consomatin genes experienced strong positive selection and repeated gene duplications resulting in the formation of a hyperdiverse family of venom peptides. Intriguingly, the largest number of consomatins was found in worm-hunting species (>400 sequences), indicating a homologous system in annelids, another large protostome phylum. Consistent with this, comprehensive sequence mining enabled the identification of SSRP-like sequences (and their corresponding orphan receptor) in annelids and several other protostome phyla. These results established the existence of SSRP-like peptides in many major branches of bilaterians and challenge the prevailing hypothesis that deuterostome SSRPs and protostome allatostatin-C are orthologous peptide families. Finally, having a large set of predator-prey SSRP sequences available, we show that although the cone snail's signaling SSRP-like genes are under purifying selection, the venom consomatin genes experience rapid directional selection to target receptors in a changing mix of prey.


Assuntos
Conotoxinas , Caramujo Conus , Animais , Conotoxinas/genética , Caramujo Conus/genética , Neuropeptídeos , Peptídeos/genética , Somatostatina/genética , Peçonhas
5.
Proteome Sci ; 21(1): 17, 2023 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-37828502

RESUMO

µ-Conotoxin GIIIB (µ-CTX GIIIB) is a polypeptide containing three disulfide bridges, produced by the sea snail Conus geographus. This study was aimed to explored the cytotoxic effects of µ-CTX GIIIB on mouse skeletal musculoblast (Sol8). Sol8 cells were exposed to ouabain and veratridine to establish the cell injury model, and then treated with µ-CTX GIIIB. CCK-8 was adopted to evaluate the cytotoxicity of µ-CTX GIIIB. Then, proteomics and transcriptome were conducted, and the explore the differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) affected by µ-CTX GIIIB were found. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis was used to investigate the affected signaling pathways. µ-CTX GIIIB increased the cell survival rate of injured Sol8 cells. We found and identified 1,663 DEGs and 444 DEPs influenced by µ-CTX GIIIB. 106 pairs of correlated DEGs and DEPs were selected by combining transcriptome and proteome data. The results of KEGG and GO analysis showed that µ-CTX GIIB affected the cell cycle, apoptosis, DNA damage and repair, lipid metabolism and other biological processes of Sol8 cells. µ-CTX GIIIB could affected cell cycle regulation, DNA damage repair, and activation of tumor factors, with potential carcinogenic effects. Our results provide an important basis for the study of in vitro toxicity, the mechanism of toxicity and injury prevention by µ-CTX GIIIB.

6.
Mar Drugs ; 21(2)2023 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-36827103

RESUMO

χ-Conotoxins are known for their ability to selectively inhibit norepinephrine transporters, an ability that makes them potential leads for treating various neurological disorders, including neuropathic pain. PnID, a peptide isolated from the venom of Conus pennaceus, shares high sequence homology with previously characterized χ-conotoxins. Whereas previously reported χ-conotoxins seem to only have a single native disulfide bonding pattern, PnID has three native isomers due to the formation of different disulfide bond patterns during its maturation in the venom duct. In this study, the disulfide connectivity and three-dimensional structure of these disulfide isomers were explored using regioselective synthesis, chromatographic coelution, and solution-state nuclear magnetic resonance spectroscopy. Of the native isomers, only the isomer with a ribbon disulfide configuration showed pharmacological activity similar to other χ-conotoxins. This isomer inhibited the rat norepinephrine transporter (IC50 = 10 ± 2 µM) and has the most structural similarity to previously characterized χ-conotoxins. In contrast, the globular isoform of PnID showed more than ten times less activity against this transporter and the beaded isoform did not display any measurable biological activity. This study is the first report of the pharmacological and structural characterization of an χ-conotoxin from a species other than Conus marmoreus and is the first report of the existence of natively-formed conotoxin isomers.


Assuntos
Conotoxinas , Caramujo Conus , Ratos , Animais , Conotoxinas/farmacologia , Dissulfetos/química , Caramujo Conus/química , Peptídeos/química , Espectroscopia de Ressonância Magnética
7.
Mar Drugs ; 21(3)2023 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-36976203

RESUMO

The venom of marine cone snails is mainly composed of peptide toxins called conopeptides, among which conotoxins represent those that are disulfide-rich. Publications on conopeptides frequently state that conopeptides attract considerable interest for their potent and selective activity, but there has been no analysis yet that formally quantifies the popularity of the field. We fill this gap here by providing a bibliometric analysis of the literature on cone snail toxins from 2000 to 2022. Our analysis of 3028 research articles and 393 reviews revealed that research in the conopeptide field is indeed prolific, with an average of 130 research articles per year. The data show that the research is typically carried out collaboratively and worldwide, and that discoveries are truly a community-based effort. An analysis of the keywords provided with each article revealed research trends, their evolution over the studied period, and important milestones. The most employed keywords are related to pharmacology and medicinal chemistry. In 2004, the trend in keywords changed, with the pivotal event of that year being the approval by the FDA of the first peptide toxin drug, ziconotide, a conopeptide, for the treatment of intractable pain. The corresponding research article is among the top ten most cited articles in the conopeptide literature. From the time of that article, medicinal chemistry aiming at engineering conopeptides to treat neuropathic pain ramped up, as seen by an increased focus on topological modifications (e.g., cyclization), electrophysiology, and structural biology.


Assuntos
Conotoxinas , Caramujo Conus , Animais , Caramujo Conus/química , Conotoxinas/farmacologia , Conotoxinas/química , Peptídeos/farmacologia , Peptídeos/uso terapêutico , Peptídeos/química , Caramujos
8.
Proc Natl Acad Sci U S A ; 117(42): 26429-26437, 2020 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-33020266

RESUMO

The escape response and rhythmic swimming in zebrafish are distinct behaviors mediated by two functionally distinct motoneuron (Mn) types. The primary (1°Mn) type depresses and has a large quantal content (Qc) and a high release probability (Pr). Conversely, the secondary (2°Mn) type facilitates and has low and variable Qc and Pr. This functional duality matches well the distinct associated behaviors, with the 1°Mn providing the strong, singular C bend initiating escape and the 2°Mn conferring weaker, rhythmic contractions. Contributing to these functional distinctions is our identification of P/Q-type calcium channels mediating transmitter release in 1°Mns and N-type channels in 2°Mns. Remarkably, despite these functional and behavioral distinctions, all ∼15 individual synapses on each muscle cell are shared by a 1°Mn bouton and at least one 2°Mn bouton. This blueprint of synaptic sharing provides an efficient way of controlling two different behaviors at the level of a single postsynaptic cell.


Assuntos
Canais de Cálcio/metabolismo , Canais de Cálcio/fisiologia , Neurônios Motores/metabolismo , Animais , Cálcio/metabolismo , Canais de Cálcio Tipo N/metabolismo , Canais de Cálcio Tipo P/metabolismo , Canais de Cálcio Tipo Q/metabolismo , Reação de Fuga/fisiologia , Neurônios Motores/fisiologia , Junção Neuromuscular/metabolismo , Terminações Pré-Sinápticas/fisiologia , Natação/fisiologia , Sinapses/metabolismo , Peixe-Zebra/metabolismo
9.
Int J Mol Sci ; 24(7)2023 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-37047495

RESUMO

Nicotinic acetylcholine receptors (nAChRs) present as many different subtypes in the nervous and immune systems, muscles and on the cells of other organs. In the immune system, inflammation is regulated via the vagus nerve through the activation of the non-neuronal α7 nAChR subtype, affecting the production of cytokines. The analgesic properties of α7 nAChR-selective compounds are mostly based on the activation of the cholinergic anti-inflammatory pathway. The molecular mechanism of neuropathic pain relief mediated by the inhibition of α9-containing nAChRs is not fully understood yet, but the role of immune factors in this process is becoming evident. To obtain appropriate drugs, a search of selective agonists, antagonists and modulators of α7- and α9-containing nAChRs is underway. The naturally occurring three-finger snake α-neurotoxins and mammalian Ly6/uPAR proteins, as well as neurotoxic peptides α-conotoxins, are not only sophisticated tools in research on nAChRs but are also considered as potential medicines. In particular, the inhibition of the α9-containing nAChRs by α-conotoxins may be a pathway to alleviate neuropathic pain. nAChRs are involved in the inflammation processes during AIDS and other viral infections; thus they can also be means used in drug design. In this review, we discuss the role of α7- and α9-containing nAChRs in the immune processes and in pain.


Assuntos
Conotoxinas , Neuralgia , Receptores Nicotínicos , Animais , Humanos , Receptores Nicotínicos/metabolismo , Neuralgia/tratamento farmacológico , Conotoxinas/uso terapêutico , Conotoxinas/química , Sistema Imunitário/metabolismo , Inflamação , Mamíferos/metabolismo
10.
Int J Mol Sci ; 24(14)2023 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-37511269

RESUMO

The first conotoxin affecting the voltage-gated potassium channels of the EAG family was identified and characterized from the venom of the vermivorous species Conus spurius from the Gulf of Mexico. This conopeptide, initially named Cs68 and later designated κO-SrVIA, is extremely hydrophobic and comprises 31 amino acid residues, including six Cysteines in the framework VI/VII, and a free C-terminus. It inhibits the currents mediated by two human EAG subtypes, Kv10.1 (IC50 = 1.88 ± 1.08 µM) and Kv11.1 (IC50 = 2.44 ± 1.06 µM), and also the human subtype Kv1.6 (IC50 = 3.6 ± 1.04 µM). Despite its clear effects on potassium channels, it shares a high sequence identity with δ-like-AtVIA and δ-TsVIA. Also, κO-SrVIA is the third conopeptide from the venom of C. spurius with effects on potassium channels, and the seventh conotoxin that blocks Kv1.6 channels.


Assuntos
Conotoxinas , Caramujo Conus , Canais de Potássio Éter-A-Go-Go , Animais , Humanos , Sequência de Aminoácidos , Conotoxinas/farmacologia , Conotoxinas/química , Caramujo Conus/química , Canais de Potássio Éter-A-Go-Go/efeitos dos fármacos , Canais de Potássio Éter-A-Go-Go/metabolismo , Canais de Potássio Éter-A-Go-Go/toxicidade , Peptídeos/química
11.
Molecules ; 28(8)2023 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-37110612

RESUMO

In the chemical synthesis of conotoxins with multiple disulfide bonds, the oxidative folding process can result in diverse disulfide bond connectivities, which presents a challenge for determining the natural disulfide bond connectivities and leads to significant structural differences in the synthesized toxins. Here, we focus on KIIIA, a µ-conotoxin that has high potency in inhibiting Nav1.2 and Nav1.4. The non-natural connectivity pattern (C1-C9, C2-C15, C4-C16) of KIIIA exhibits the highest activity. In this study, we report an optimized Fmoc solid-phase synthesis of KIIIA using various strategies. Our results indicate that free random oxidation is the simplest method for peptides containing triple disulfide bonds, resulting in high yields and a simplified process. Alternatively, the semi-selective strategy utilizing Trt/Acm groups can also produce the ideal isomer, albeit with a lower yield. Furthermore, we performed distributed oxidation using three different protecting groups, optimizing their positions and cleavage order. Our results showed that prioritizing the cleavage of the Mob group over Acm may result in disulfide bond scrambling and the formation of new isomers. We also tested the activity of synthesized isomers on Nav1.4. These findings provide valuable guidance for the synthesis of multi-disulfide-bonded peptides in future studies.


Assuntos
Conotoxinas , Conotoxinas/química , Peptídeos/química , Isomerismo , Oxirredução , Dissulfetos/química
12.
Biotechnol Appl Biochem ; 69(4): 1611-1621, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34337794

RESUMO

Conotoxins are small cysteine-rich peptides secreted by the Conus venom glands, which act on ion channels or membrane receptors with high specificity and potency. Conotoxins are invaluable sources for neuroscience research and drug leads, but their application is hindered by the limited successes in quantitative engineering using either chemical or biotechnological approaches. Here, we explore the Pichia pastoris to express 23 selected conopeptides using a GFP-based fluorescence screen. We found that, in a protease-deficient strain PichiaPink™ Strain 4 (ade2 prb1 pep4), most of the recombinant conopeptides were expressed as two major folding variants including a compact form that was somehow resistant to reduction and high temperature. The GFP-αTxIA was the only one displaying a single band that showed a dose-dependent neurotoxicity on larvae of the insect Plutella xylostella, with a 48-h LD50 lower than 1.12 pmol mg-1 body weight. Furthermore, the recombinant αTxIA after cleavage from the fusion was able to inhibit cell proliferation of the LYCT and HEK293T cell lines with an appearance IC50 of 341 ± 8 and 235 ± 15 nM, respectively. This screening method is straightforward and easy to scale up, providing a versatile tool for further optimization of conotoxin production in the yeast cell.


Assuntos
Conotoxinas , Caramujo Conus , Saccharomycetales , Animais , Conotoxinas/metabolismo , Conotoxinas/farmacologia , Caramujo Conus/metabolismo , Células HEK293 , Humanos , Pichia/genética , Pichia/metabolismo , Saccharomycetales/metabolismo
13.
Mar Drugs ; 20(2)2022 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-35200683

RESUMO

The voltage-gated sodium channel subtype 1.2 (NaV1.2) is instrumental in the initiation of action potentials in the nervous system, making it a natural drug target for neurological diseases. Therefore, there is much pharmacological interest in finding blockers of NaV1.2 and improving their affinity and selectivity properties. An extensive family of peptide toxins from cone snails (conotoxins) block NaV channels, thus they provide natural templates for the design of drugs targeting NaV channels. Unfortunately, progress was hampered due to the absence of any NaV structures. The recent determination of cryo-EM structures for NaV channels has finally broken this impasse. Here, we use the NaV1.2 structure in complex with µ-conotoxin KIIIA (KIIIA) in computational studies with the aim of improving KIIIA's affinity and blocking capacity for NaV1.2. Only three KIIIA amino acid residues are available for mutation (S5, S6, and S13). After performing molecular modeling and simulations on NaV1.2-KIIIA complex, we have identified the S5R, S6D, and S13K mutations as the most promising for additional contacts. We estimate these contacts to boost the affinity of KIIIA for NaV1.2 from nanomole to picomole domain. Moreover, the KIIIA[S5R, S6D, S13K] analogue makes contacts with all four channel domains, thus enabling the complete blocking of the channel (KIIIA partially blocks as it has contacts with three domains). The proposed KIIIA analogue, once confirmed experimentally, may lead to novel anti-epileptic drugs.


Assuntos
Conotoxinas/farmacologia , Canal de Sódio Disparado por Voltagem NAV1.2/efeitos dos fármacos , Bloqueadores do Canal de Sódio Disparado por Voltagem/farmacologia , Sequência de Aminoácidos , Animais , Anticonvulsivantes/química , Anticonvulsivantes/farmacologia , Conotoxinas/química , Caramujo Conus , Desenho de Fármacos , Humanos , Modelos Moleculares , Simulação de Dinâmica Molecular , Mutação , Bloqueadores do Canal de Sódio Disparado por Voltagem/química , Bloqueadores do Canal de Sódio Disparado por Voltagem/isolamento & purificação
14.
Mar Drugs ; 20(12)2022 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-36547920

RESUMO

Conus regius is a marine venomous mollusk of the Conus genus that captures its prey by injecting a rich cocktail of bioactive disulfide bond rich peptides called conotoxins. These peptides selectively target a broad range of ion channels, membrane receptors, transporters, and enzymes, making them valuable pharmacological tools and potential drug leads. C. regius-derived conotoxins are particularly attractive due to their marked potency and selectivity against specific nicotinic acetylcholine receptor subtypes, whose signalling is involved in pain, cognitive disorders, drug addiction, and cancer. However, the species-specific differences in sensitivity and the low stability and bioavailability of these conotoxins limit their clinical development as novel therapeutic agents for these disorders. Here, we give an overview of the main pharmacological features of the C. regius-derived conotoxins described so far, focusing on the molecular mechanisms underlying their potential therapeutic effects. Additionally, we describe adoptable chemical engineering solutions to improve their pharmacological properties for future potential clinical translation.


Assuntos
Conotoxinas , Caramujo Conus , Receptores Nicotínicos , Animais , Conotoxinas/farmacologia , Conotoxinas/química , Organismos Aquáticos , Caramujo Conus/química , Peptídeos/farmacologia , Antagonistas Nicotínicos/farmacologia
15.
Mar Drugs ; 20(12)2022 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-36547897

RESUMO

α-conotoxin AuIB is the only one of the 4/6 type α-conotoxins (α-CTxs) that inhibits the γ-aminobutyric acid receptor B (GABABR)-coupled N-type calcium channel (CaV2.2). To improve its inhibitory activity, a series of variants were synthesized and evaluated according to the structure-activity relationships of 4/7 type α-CTxs targeting GABABR-coupled CaV2.2. Surprisingly, only the substitution of Pro7 with Arg results in a 2-3-fold increase in the inhibition of GABABR-coupled CaV2.2 (IC50 is 0.74 nM); substitutions of position 9-12 with basic or hydrophobic amino acid and the addition of hydrophobic amino acid Leu or Ile at the second loop to mimic 4/7 type α-CTxs all failed to improve the inhibitory activity of AuIB against GABABR-coupled CaV2.2. Interestingly, the most potent form of AuIB[P7R] has disulfide bridges of "1-4, 2-3" (ribbon), which differs from the "1-3, 2-4" (globular) in the isoforms of wildtype AuIB. In addition, AuIB[P7R](globular) displays potent analgesic activity in the acetic acid writhing model and the partial sciatic nerve injury (PNL) model. Our study demonstrated that 4/6 type α-CTxs, with the disulfide bridge connectivity "1-4, 2-3," are also potent inhibitors for GABABR-coupled CaV2.2, exhibiting potent analgesic activity.


Assuntos
Conotoxinas , Receptores Nicotínicos , Aminoácidos , Conotoxinas/química , Analgésicos/farmacologia , Analgésicos/química , Canais de Cálcio Tipo N/metabolismo , Dissulfetos/química , Ácido gama-Aminobutírico , Receptores Nicotínicos/metabolismo
16.
Mar Drugs ; 20(5)2022 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-35621933

RESUMO

Voltage-gated ion channels are plasma membrane proteins that generate electrical signals following a change in the membrane voltage. Since they are involved in several physiological processes, their dysfunction may be responsible for a series of diseases and pain states particularly related to neuronal and muscular systems. It is well established for decades that bioactive peptides isolated from venoms of marine mollusks belonging to the Conus genus, collectively known as conotoxins, can target different types and isoforms of these channels exerting therapeutic effects and pain relief. For this reason, conotoxins are widely used for either therapeutic purposes or studies on ion channel mechanisms of action disclosure. In addition their positive property, however, conotoxins may generate pathological states through similar ion channel modulation. In this narrative review, we provide pieces of evidence on the pathophysiological impacts that different members of conotoxin families exert by targeting the three most important voltage-gated channels, such as sodium, calcium, and potassium, involved in cellular processes.


Assuntos
Conotoxinas , Canais Iônicos , Animais , Conotoxinas/química , Caramujo Conus , Humanos , Canais Iônicos/efeitos dos fármacos , Dor/tratamento farmacológico
17.
Mar Drugs ; 20(2)2022 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-35200678

RESUMO

The venom duct transcriptomes and proteomes of the cryptic cone snail species Virroconus ebraeus and Virroconus judaeus were obtained and compared. The most abundant and shared conotoxin precursor superfamilies in both species were M, O1, and O2. Additionally, three new putative conotoxin precursor superfamilies (Virro01-03) with cysteine pattern types VI/VII and XVI were identified. The most expressed conotoxin precursor superfamilies were SF-mi2 and M in V. ebraeus, and Cerm03 and M in V. judaeus. Up to 16 conotoxin precursor superfamilies and hormones were differentially expressed between both species, and clustered into two distinct sets, which could represent adaptations of each species to different diets. Finally, we predicted, with machine learning algorithms, the 3D structure model of selected venom proteins including the differentially expressed Cerm03 and SF-mi2, an insulin type 3, a Gastridium geographus GVIA-like conotoxin, and an ortholog to the Pionoconus magus ω-conotoxin MVIIA (Ziconotide).


Assuntos
Caramujo Conus , Venenos de Moluscos/química , Proteínas/química , Algoritmos , Animais , Aprendizado de Máquina , Proteínas/isolamento & purificação , Proteoma , Especificidade da Espécie , Transcriptoma
18.
Molecules ; 27(19)2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-36235146

RESUMO

Conotoxins constitute a treasury of drug resources and have attracted widespread attention. In order to explore biological candidates from the marine cone snail, we isolated and identified three novel conopeptides named as Vi14b, Vi002, Vi003, three conotoxin variants named as Mr3d.1, Mr3e.1, Tx3a.1, and three known conotoxins (Vi15a, Mr3.8 and TCP) from crude venoms of Conus virgo, Conus marmoreus and Conus texile. Mr3.8 (I-V, II-VI, III-IV) and Tx3a.1 (I-III, II-VI, IV-V) both showed a novel pattern of disulfide connectivity, different from that previously established for the µ- and ψ-conotoxins. Concerning the effect on voltage-gated sodium channels, Mr3e.1, Mr3.8, Tx3a.1, TCP inhibited Nav1.4 or Nav1.8 by 21.51~24.32% of currents at semi-activated state (TP2) at 10 µmol/L. Certain anti-ovarian cancer effects on ID-8 cells were exhibited by Tx3a.1, Mr3e.1 and Vi14b with IC50 values of 24.29 µM, 54.97 µM and 111.6 µM, respectively. This work highlights the role of conotoxin libraries in subsequent drug discovery for ovarian cancer treatment.


Assuntos
Conotoxinas , Caramujo Conus , Neoplasias , Animais , Conotoxinas/farmacologia , Caramujo Conus/genética , DNA Complementar , Dissulfetos , Venenos de Moluscos
19.
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
20.
Bioorg Chem ; 112: 104875, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33823404

RESUMO

Head-to-tail cyclization is an effective strategy to improve the biological stability of peptides. The α-conotoxin [S9A]TxID is a peptide that inhibits α3ß4 nAChR with high activity and selectivity. Herein, we established a method for cyclizing and oxidative folding of [S9A]TxID, and six cyclic analogues of [S9A]TxID were chemically synthesized with various linker lengths. We used the electrophysiology assay to measure activity values of these cyclic analogues, and obtained the most potent analogue c[S9A]TxID-6, which was more stable than native [S9A]TxID against proteinase K.


Assuntos
Conotoxinas/farmacologia , Dissulfetos/farmacologia , Antagonistas Nicotínicos/farmacologia , Receptores Nicotínicos/metabolismo , Conotoxinas/síntese química , Conotoxinas/química , Dissulfetos/química , Relação Dose-Resposta a Droga , Humanos , Simulação de Dinâmica Molecular , Estrutura Molecular , Antagonistas Nicotínicos/síntese química , Antagonistas Nicotínicos/química , Relação Estrutura-Atividade
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