Inhibitors of the voltage-gated sodium channel Na_V1.7 are being investigated as pain therapeutics due to compelling human genetics. We previously identified Na_V1.7-inhibitory peptides GpTx-1 and JzTx-V from tarantula venom screens. Potency and selectivity were modulated through attribute-based positional scans of native residues via chemical synthesis. Herein, we report JzTx-V lead optimization to identify a pharmacodynamically active peptide variant. Molecular docking of peptide ensembles from NMR into a homology model-derived Na_V1.7 structure supported prioritization of key residues clustered on a hydrophobic face of the disulfide-rich folded peptide for derivatization. Replacing Trp24 with 5-Br-Trp24 identified lead peptides with activity in electrophysiology assays in engineered and neuronal cells. 5-Br-Trp24 containing peptide AM-6120 was characterized in X-ray crystallography and pharmacokinetic studies and blocked histamine-induced pruritis in mice after subcutaneous administration, demonstrating systemic Na_V1.7-dependent pharmacodynamics. Our data suggests a need for high target coverage based on plasma exposure for impacting in vivo end points with selectivity-optimized peptidic Na_V1.7 inhibitors.

中文翻译：

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发现有狼蛛毒液的Na _V 1.7抑制性JzTx-V肽5-Br-Trp24类似物AM-6120与组胺诱导的瘙痒症的系统性阻滞

由于令人信服的人类遗传学，正在研究电压门控钠通道Na _V 1.7的抑制剂作为止痛药。我们先前从狼蛛毒液筛选中鉴定了Na _V 1.7抑制肽GpTx-1和JzTx-V。通过化学合成，通过对天然残基进行基于属性的位置扫描来调节效能和选择性。在此，我们报告了JzTx-V前导优化，以鉴定药效学活性肽变体。肽分子从NMR分子对接到同源模型衍生的Na _V中1.7结构支持聚集在富含二硫键的折叠肽的疏水面上用于衍生的关键残基的优先顺序。用5-Br-Trp24取代Trp24可在工程细胞和神经元细胞的电生理测定中鉴定出具有活性的先导肽。含有5-Br-Trp24的肽AM-6120在X射线晶体学和药代动力学研究中得到了表征，并在皮下给药后阻断了小鼠中的组胺诱发的瘙痒症，证明了全身Na _V 1.7依赖的药效学。我们的数据表明需要基于血浆暴露的高目标覆盖率，以使用选择性优化的肽Na _V 1.7抑制剂影响体内终点。