Abstract

The neuropeptide nocistatin (NS) is expressed by the nervous system cells and neutrophils as a part of a precursor protein and can undergo stepwise limited proteolysis. Previously, it was shown that rat NS (rNS) is able to activate acid-sensing ion channels (ASICs) and that this effect correlates with the acidic nature of NS. Here, we investigated changes in the properties of rNS in the course of its proteolytic degradation by comparing the effects of the full-size rNS and its two cleavage fragments on the rat isoform 3 ASICs (ASIC3) expressed in X. laevis oocytes and pain perception in mice. The rNS acted as both positive and negative modulator by lowering the steady-state desensitization of ASIC3 at pH 6.8-7.0 and reducing the channel’s response to stimuli at pH 6.0-6.9, respectively. The truncated rNSΔ21 peptide lacking 21 amino acid residues from the N-terminus retained the positive modulatory activity, while the C-terminal pentapeptide (rNSΔ30) acted only as a negative ASIC3 modulator. The effects of the studied peptides were confirmed in animal tests: rNS and rNSΔ21 induced a pain-related behavior, whereas rNSΔ30 showed the analgesic effect. Therefore, we have shown that the mode of rNS action changes during its stepwise degradation, from an algesic molecule through a pain enhancer to a pain reliever (rNSΔ30 pentapeptide), which can be considered as a promising drug candidate.

中文翻译：

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Nocistatin 及其蛋白水解产物是具有止痛和镇痛特性的 3 型酸敏感离子通道 (ASIC3) 的双重调节剂

摘要

神经肽诺西他汀 (NS) 作为前体蛋白的一部分由神经系统细胞和中性粒细胞表达，并且可以进行逐步有限的蛋白水解。此前，研究表明，大鼠 NS (rNS) 能够激活酸敏感离子通道 (ASIC)，并且这种效应与 NS 的酸性性质相关。在这里，我们通过比较全尺寸 rNS 及其两个切割片段对非洲爪蟾卵母细胞中表达的大鼠亚型 3 ASIC (ASIC3) 和疼痛感知的影响，研究了 rNS 在蛋白水解降解过程中特性的变化。在小鼠中。rNS 分别通过降低 ASIC3 在 pH 6.8-7.0 下的稳态脱敏和减少通道对 pH 6.0-6.9 刺激的响应来充当正调节剂和负调节剂。N 端缺少 21 个氨基酸残基的截短 rNSΔ21 肽保留了正调节活性，而 C 端五肽 (rNSΔ30) 仅充当负 ASIC3 调节剂。所研究的肽的作用在动物试验中得到证实：rNS 和 rNSΔ21 诱导疼痛相关行为，而 rNSΔ30 显示镇痛作用。因此，我们发现rNS作用模式在其逐步降解过程中发生变化，从镇痛分子通过疼痛增强剂转变为止痛剂（rNSΔ30五肽），这可以被认为是一种有前途的候选药物。