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Management of chronic pain presents a major challenge, since many currently available treatments lack efficacy and have problems such as addiction and tolerance. Loss of function mutations in the SCN9A gene lead to a congenital inability to feel pain, with no other sensory deficits aside from anosmia. SCN9A encodes the voltage-gated sodium (Na V ) channel 1.7 (Na V 1.7), which has been identified as a primary pain target. However, in developing Na V 1.7-targeted analgesics, extreme care must to be taken to avoid off-target activity on other Na V subtypes that are critical for survival. Since spider venoms are an excellent source of Na V channel modulators, we screened a panel of spider venoms to identify selective Na V 1.7 inhibitors. This led to identification of two novel Na V modulating venom peptides (β/μ-theraphotoxin-Pe1a and β/μ-theraphotoxin-Pe1b (Pe1b) from the arboreal tarantula Phormingochilus everetti. A third peptide isolated from the tarantula Bumba pulcherrimaklaasi was identical to the well-known ProTx-I (β/ω-theraphotoxin-Tp1a) from the tarantula Thrixopelma pruriens. A tethered toxin (t-toxin)-based alanine scanning strategy was used to determine the Na V 1.7 pharmacophore of ProTx-I. We designed several ProTx-I and Pe1b analogues, and tested them for activity and Na V channel subtype selectivity. Several analogues had improved potency against Na V 1.7, and altered specificity against other Na V channels. These analogues provide a foundation for development of Pe1b as a lead molecule for therapeutic inhibition of Na V 1.7., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Voltage-gated sodium (Na(V)) channels play a central role in the propagation of action potentials in excitable cells in both humans and insects. Many venomous animals have therefore evolved toxins that modulate the activity of Na(V) channels in order to subdue their prey and deter predators. Spider venoms in particular are rich in Na(V) channel modulators, with one-third of all known ion channel toxins from spider venoms acting on Na(V) channels. Here we review the landscape of spider-venom peptides that have so far been described to target vertebrate or invertebrate Na(V) channels. These peptides fall into 12 distinct families based on their primary structure and cysteine scaffold. Some of these peptides have become useful pharmacological tools, while others have potential as therapeutic leads because they target specific Na(V) channel subtypes that are considered to be important analgesic targets. Spider venoms are conservatively predicted to contain more than 10 million bioactive peptides and so far only 0.01% of this diversity been characterised. Thus, it is likely that future research will reveal additional structural classes of spider-venom peptides that target Na(V) channels., (Copyright © 2012 Elsevier Ltd. All rights reserved.)