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Promiscuity, comparison of the affinities of the five toxins among the different ion channels. The z axis represents the reciprocal of the IC 50 values (in M Ϫ 1 ) of the peak current blockade. The x axis represents the different peptides. The y axis is the list of all the channels investigated in
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Venom-derived peptide modulators of ion channel gating are regarded as essential tools for understanding the molecular motions
that occur during the opening and closing of ion channels. In this study, we present the characterization of five spider toxins
on 12 human voltage-gated ion channels, following observations about the target promiscuity of...
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... comprehensive analysis of Na and K channels is shown under a three-dimensional graph in Fig. 6. Promiscuity can be observed as the change in the height of adjacent bars. In con- trast, vulnerability can be appreciated by observing the height of aligned parallel bars but in different colors. GsMTx4 is the most promiscuous because it can block, with low affinity, both Na and K ...
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Voltage dependent sodium (NaV) channels are large membrane spanning proteins which lie in the basis of action potential generation and propagation in excitable cells and hence are essential mediators of neuronal signaling. Inhibition of NaV channel activity is one of the core mechanisms to treat conditions related to neuronal hyperexcitability, suc...
Citations
... Local injection of D-GsMTx4 (1.25 mM) resulted in a significant reduction or even complete block of slow oscillations in all experiments but no significant change in spike rate or LFP activity (n = 13 NBPs; Fig. 4C and table S1). The latter indicates that overall network activity was not affected, although antagonistic effects of D-GsMTx4 on voltage-gated channels (Na v and K v ) have been reported for higher concentrations [median inhibitory concentration (IC 50 ) in the 10-mM range] (31). The insensitivity of spike rate to D-GsMTx4 instead implies that the oscillatory increase in excitability through mechanosensitive channel activation was subthreshold for spike generation (Discussion). ...
The transmission of the heartbeat through the cerebral vascular system causes intracranial pressure pulsations. We discovered that arterial pressure pulsations can directly modulate central neuronal activity. In a semi-intact rat brain preparation, vascular pressure pulsations elicited correlated local field oscillations in the olfactory bulb mitral cell layer. These oscillations did not require synaptic transmission but reflected baroreceptive transduction in mitral cells. This transduction was mediated by a fast excitatory mechanosensitive ion channel and modulated neuronal spiking activity. In awake animals, the heartbeat entrained the activity of a subset of olfactory bulb neurons within ~20 milliseconds. Thus, we propose that this fast, intrinsic interoceptive mechanism can modulate perception—for example, during arousal—within the olfactory bulb and possibly across various other brain areas.
... The gating modifier compounds that target the S1-S4 domains often exhibit promiscuous interactions with different types of ion channels. For example, many tarantula toxins demonstrate simultaneous activity against several subtypes of Na + and K + channels [30]. This also applies to the toxins which inhibit Ca 2+ channels; many of them are also active against Na + and K + channels ( Figure 1, green symbols). ...
Phα1β (PnTx3–6) is a neurotoxin from the spider Phoneutria nigriventer venom, originally identified as an antagonist of two ion channels involved in nociception: N-type voltage-gated calcium channel (CaV2.2) and TRPA1. In animal models, Phα1β administration reduces both acute and chronic pain. Here, we report the efficient bacterial expression system for the recombinant production of Phα1β and its 15N-labeled analogue. Spatial structure and dynamics of Phα1β were determined via NMR spectroscopy. The N-terminal domain (Ala1–Ala40) contains the inhibitor cystine knot (ICK or knottin) motif, which is common to spider neurotoxins. The C-terminal α-helix (Asn41–Cys52) stapled to ICK by two disulfides exhibits the µs–ms time-scale fluctuations. The Phα1β structure with the disulfide bond patterns Cys1–5, Cys2–7, Cys3–12, Cys4–10, Cys6–11, Cys8–9 is the first spider knottin with six disulfide bridges in one ICK domain, and is a good reference to other toxins from the ctenitoxin family. Phα1β has a large hydrophobic region on its surface and demonstrates a moderate affinity for partially anionic lipid vesicles at low salt conditions. Surprisingly, 10 µM Phα1β significantly increases the amplitude of diclofenac-evoked currents and does not affect the allyl isothiocyanate (AITC)-evoked currents through the rat TRPA1 channel expressed in Xenopus oocytes. Targeting several unrelated ion channels, membrane binding, and the modulation of TRPA1 channel activity allow for considering Phα1β as a gating modifier toxin, probably interacting with S1–S4 gating domains from a membrane-bound state.
... VsTx1 inhibits Nav1.7 and Kv1.1 channels by partitioning in lipid membranes. 61 The peptide U2-TRTX-Aj1a (m/z 822,36 +6 ) is a new toxin with three disulfide bonds (CF−I) and homology to Genicutoxin-B2 from A. geniculata, 7 U2-TRTX-Ar1a from A. rondoniae, 8 Ω-TRTX-Bs2a from Brachypelma smithi, 62 and U11-TRTX-Hhn1v from Haplopelma hainanum ( Figure S3), among others. Ω-TRTX-Bs2a has significant effects on the Para/tipE insect sodium channels, 62 and U11-TRTX-Hhn1v New proteoforms of U1-TRTX-Ap1a were also observed. ...
Acanthoscurria juruenicola is an Amazonian spider described for the first time almost a century ago. However, little is known about their venom composition. Here, we present a multiomics characterization of A. juruenicola venom by a combination of transcriptomics, proteomics, and peptidomics approaches. Transcriptomics of female venom glands resulted in 93,979 unique assembled mRNA transcript encoding proteins. A total of 92 proteins were identified in the venom by mass spectrometry, including 14 mature cysteine-rich peptides (CRPs). Quantitative analysis showed that CRPs, cysteine-rich secretory proteins, metalloproteases, carbonic anhydrases, and hyaluronidase comprise >90% of the venom proteome. Relative quantification of venom toxins was performed by DIA and DDA, revealing converging profiles of female and male specimens by both methods. Biochemical assays confirmed the presence of active hyaluronidases, phospholipases, and proteases in the venom. Moreover, the venom promoted in vivo paralytic activities in crickets, consistent with the high concentration of CRPs. Overall, we report a comprehensive analysis of the arsenal of toxins of A. juruenicola and highlight their potential biotechnological and pharmacological applications. Mass spectrometry data were deposited to the ProteomeXchange Consortium via the PRIDE repository with the dataset identifier PXD013149 and via the MassIVE repository with the dataset identifier MSV000087777.
... All these theraphotoxins are also neurotoxins that act in ion channels. According to Redaelli et al. (2010), arachnid neurotoxins can also be potent antimicrobial molecules as, for example, the Cupienins 1a, 1b, 1c, and 1d Avilin, Juruin_2, and Juruenine probably have the ICK motif in their structure. ...
Considering that there are still many species little-studied, this work aimed to analyze the venom of the spider Avicularia juruensis searching for antimicrobial peptides. Using reverse-phase high-performance liquid chromatography, microbial growth inhibition assay, transcriptomics, and proteomics approaches we identified three antimicrobial peptides: Avilin, Juruin_2, and Juruenine. All of them showed similarities with neurotoxins that act on ion channels and, probably, they have the ICK motif. The study of animal venoms is of great importance to carry out the characterization of unknown components and that may have a biotechnological application, in special venoms from spiders that are from less studied families.
Spiders are the most successful group of venomous animals, comprising more than 50,350 species distributed in all terrestrial habitats. One strategy that facility their broad distribution is the production of elaborate venoms, which are composed of inorganic salts, organic molecules with low molecular mass, free amino acids, small polypeptides, linear peptides, nucleotides, disulfide-rich peptides, enzymes, and high molecular mass proteins. Considering that there are still many species little-studied, this work aimed to analyze the venom of the mygalomorph spider Avicularia juruensis searching for new antimicrobial peptides. Using reverse-phase high-performance liquid chromatography, microbial growth inhibition assay, transcriptomics, and proteomics approaches we identified three antimicrobial peptides that were named Avilin, Juruin_2, and Juruenine. All of them showed similarities with neurotoxins that act on ion channels and, probably, they have the ICK motif in their structure. The ICK fold seems to be conserved in several venomous animal lineages and presents elevated functional diversity, as well as gives stability to the toxins. The study of animal venoms is of great importance to carry out the characterization of unknown components and that may have a biotechnological application (like the antimicrobial peptides), in special venoms from spiders that are from less studied families.
... We suggested that Pept 01 may mimic the parent peptide GsMTx4 to act as a mechano-sensitive BK (SAKcaC) inhibitor. Nevertheless, GsMTx4 has been suggested to act as the selective MSC inhibitor and blocks a variety of ion channels, including Na + channels (45), and the MS TRPC (e.g., TRPC1, TRPC6) (34) and Piezo1/Piezo2 (28) channels. Whether these short peptides act as an MS-selective inhibitor as GsMTx4 and impact the activities of these ion channels needs further investigation. ...
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in humans. Current AF antiarrhythmic drugs have limited efficacy and carry the risk of ventricular pro-arrhythmia. GsMTx4, a mechanosensitive channel (MSC)-selective inhibitor, has been shown to suppress arrhythmias through the inhibition of stretch-activated channels (SACs) in the heart. The cost of synthesizing this peptide is a major obstacle to clinical use. Here, we studied two types of short peptides derived from GsMTx4 for their effects on a stretch-activated big potassium (BK) channel (SAKcaC) from the heart. Type I, a 17-residue peptide (referred to as Pept 01), showed comparable efficacy, whereas type II (i.e. Pept 02), a 10-residue peptide, exerted even more potent inhibitory efficacy on SAKcaC compared to GsMTx4. We identified through mutagenesis important sequences required for peptide functions. Additionally, molecular dynamics (MD) simulations revealed common structural features with a hydrophobic head followed by a positively charged protrusion that may be involved in peptide-channel/lipid interactions. Furthermore, we suggest that these short peptides may inhibit SAKcaC through a specific modification to the mechano-gate, as the inhibitory effects for both types of peptides were mostly abolished when tested with a mechano-insensitive channel variant (STREX-del) and a non-mechanosensitive BK (mSlo1) channel. These findings may offer an opportunity for the development of a new class of drugs in the treatment of cardiac arrhythmia generated by excitatory SACs in the heart..
... Indeed, a number of approved analgesics are derived from natural products; for example, salicylic acid isolated from the Salix alba tree was modified to obtain the commercial version acetylsalicylic acid (commonly known as aspirin); morphine and menthol were isolated from the plants Papaver somniferum and Mentha piperita, respectively (Mccurdy and Scully 2005); and ziconotide is a peptide isolated from the venom of the cone snail Conus magus (Mcgivern 2007). Peptides are abundant in natural products and have been shown to either specifically act on one channel; for example Na v 1.7, one of the most studied ion channels involved in pain transmission (Schmalhofer et al. 2008), or to have promiscuous activity, blocking or activating different channels and receptors (Redaelli et al. 2010, Cardoso et al. 2017. Peptides can be isolated from different natural sources, including animal venoms (Senji Laxme et al. 2019). ...
... These peptides act on Ca v channels, L, N and P/Q-type (Dos Santos et al. 2002, Takeuchi et al. 2002, while the peptide p-TRTX-Hm3a inhibits specifically ASIC channels, and has a high affinity to the subtype ASIC1a (Er et al. 2017). The majority of analgesic spider peptides act on Na v channels involved in pain transmission and includes the peptides GsAFI and GsAFII (Redaelli et al. 2010, Ono et al. 2011, b/ltheraphotoxin-Pe1b (Rupasinghe et al. 2020), phrixotoxins 1 and 3, voltage sensor toxin (VsTx)-1 and 3, b/d-TRTX-Pre1a, l-TRTX-Phlo1a, -Phlo1b and -Phlo2a and l-TRTX-Hd1a (see review by Dongol et al. (2019)). Despite their potent in vitro activity, in vivo assays have not yet been reported with these peptides. ...
Many analgesic peptides have been isolated from arthropod species such as spiders and scorpions and their three-dimensional structures, which are typically stabilized by several disulfide-bonds, correlate with their activity and molecular targets. In contrast, only individual species of Chilopoda (centipedes) and Insecta (Hymenoptera) have been described to contain antinociceptive peptides and those display only α-helical structures, with the latter also lacking disulfide bonds. Here we review the structural diversity of antinociceptive arthropod peptides and highlight their largely untapped potential for the discovery of novel analgesic lead molecules.
... In summary, we show here that a single venom peptide can modulate three major determinants of neuronal excitability. Target promiscuity, defined as the ability to modulate the function of more than one type of receptor, is a common feature of spider toxins (23,59). Many gating-modifier toxins are highly promiscuous and target a wide range of ion channels and receptors (23,59). ...
... Target promiscuity, defined as the ability to modulate the function of more than one type of receptor, is a common feature of spider toxins (23,59). Many gating-modifier toxins are highly promiscuous and target a wide range of ion channels and receptors (23,59). For example, Protoxin-I (β/ω-TRTX-Tp1a) from venom of the tarantula Thrixopelma pruriens targets a wide range of Na V channels, Ca V 3.1, and TRPA1 (transient receptor potential ankyrin 1) (60). ...
Significance
Pain development and discomfort are universal features of spider envenomation, yet severe pain arising from bites by Old World spiders is poorly understood. Molecular analyses of the venom of the King Baboon spider revealed abundant expression of the inhibitory cystine knot peptide Pm1a. Synthetic Pm1a induces pain in mice while simultaneously enhancing proexcitatory sodium currents and decreasing inhibitory potassium currents. These concomitant effects promote hyperexcitability in pain-sensing neurons that can be reversed by pharmacological inhibition of voltage-gated sodium channels. The coordinated modulation of excitatory and inhibitory ion channels involved in pain propagation may represent an economical and effective defense strategy in pain-inducing defensive venoms.
... For example, the Hanatoxin (HaTx1) [72] and HpTx1 [73] (patent) toxins show effect on Ca 2+ and K + channels. On the other hand, the VsTx1 [74], PaTx1 [75,76], HmTx1 [77,78] and GiTx1 [79] toxins have been reported as Na + and K + channel modulators. Furthermore, it has been discovered that in the toxin-channel interaction, the lipids in the cell membrane are also involved [80,81]. ...
... Another example is the toxin Gr1b. This peptide inhibits the Nav1.7 channel with a Kd value of 40 nM and exhibits 10-to 30-fold selectivity over other Nav channels [74]. In this case, the small molecule tetrodotoxin (TTX) shows a slightly higher affinity for Nav channels (Kd value of 4 to 25 nM). ...
The human voltage gated potassium channel Kv1.5 that conducts the IKur current is a key determinant of the atrial action potential. Its mutations have been linked to hereditary forms of atrial fibrillation (AF), and the channel is an attractive target for the management of AF. The development of IKur blockers to treat AF resulted in small molecule Kv1.5 inhibitors. The selectivity of the blocker for the target channel plays an important role in the potential therapeutic application of the drug candidate: the higher the selectivity, the lower the risk of side effects. In this respect, small molecule inhibitors of Kv1.5 are compromised due to their limited selectivity. A wide range of peptide toxins from venomous animals are targeting ion channels, including mammalian channels. These peptides usually have a much larger interacting surface with the ion channel compared to small molecule inhibitors and thus, generally confer higher selectivity to the peptide blockers. We found two peptides in the literature, which inhibited IKur: Ts6 and Osu1. Their affinity and selectivity for Kv1.5 can be improved by rational drug design in which their amino acid sequences could be modified in a targeted way guided by in silico docking experiments.
... GsAF-I hNav1.7: 1-40 nM (tc) ND [203,204] β-TRTX-Gr2c GsAFII hNav1.7: 13.6-1000 nM (tc) ND [203,204] β-TRTX-Gr1a GrTx1 hNav1.7: ...
... 1-40 nM (tc) ND [203,204] β-TRTX-Gr2c GsAFII hNav1.7: 13.6-1000 nM (tc) ND [203,204] β-TRTX-Gr1a GrTx1 hNav1.7: 15-370 nM (tc) ND [203,204] Hadronyche infensa π-TRTX-Hi1a ...
... 13.6-1000 nM (tc) ND [203,204] β-TRTX-Gr1a GrTx1 hNav1.7: 15-370 nM (tc) ND [203,204] Hadronyche infensa π-TRTX-Hi1a ...
Abstract Pain is a common symptom induced during envenomation by spiders and scorpions. Toxins isolated from their venom have become essential tools for studying the functioning and physiopathological role of ion channels, as they modulate their activity. In particular, toxins that induce pain relief effects can serve as a molecular basis for the development of future analgesics in humans. This review provides a summary of the different scorpion and spider toxins that directly interact with pain-related ion channels, with inhibitory or stimulatory effects. Some of these toxins were shown to affect pain modalities in different animal models providing information on the role played by these channels in the pain process. The close interaction of certain gating-modifier toxins with membrane phospholipids close to ion channels is examined along with molecular approaches to improve selectivity, affinity or bioavailability in vivo for therapeutic purposes.
... The significant difference is Glu10, Glu17, and Lys25 in JZTX-XIII which are replaced by Thr/Ser, Lys/Pro, and Leu in JZTX-35 and JZTX-IV (circled with rectangle). The acidic residues of Glu10 and Glu17 are conserved in GrTx1 and GsAFI, which are gating modifiers of the hERG channel isolated from the tarantula venom (Redaelli et al., 2010). JZTX-I and JZTX-III share 66% sequence similarity. ...
Jingzhaotoxin-I, -III, -IV, -XIII, and −35 (JZTX-I, -III, -IV, -XIII, and −35), gating modifier toxins isolated from the venom of the Chinese tarantula Chilobrachys Jingzhao, were reported to act on cardiac sodium channels and Kv channels. JZTX-I and JZTX-XIII inhibited the hERG channel with the IC50 value of 626.9 nM and 612.6 nM, respectively. JZTX-III, -IV, and −35 share high sequence similarity with JZTX-I and JZTX–XIII, but they showed much lower affinity on the hERG channel compared with JZTX-I and JZTX-XIII. The inhibitory potency of the above five toxins on the hERG channel was not in accordance with their affinity on the Nav1.5 and Kv2.1 channels, indicating that the bioactive surfaces of the five toxins interacting with hERG, Nav1.5 and Kv2.1 are at least in part different. Structure-function analysis of the gating modifier toxins suggested that the functional bioactive surface binding to the hERG channel consists of a conserved hydrophobic patch, surrounding acidic residues (Glu10 in JZTX-XIII, Glu11 in JZTX-I), and basic residues which may be different from residues binding to the Kv2.1 channel.
