Proteolysis controls endogenous substance P levels.
Proteolysis controls endogenous substance P levels.
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DOI：
10.1371/journal.pone.0068638
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Saghatelian A
中科院分区：
文献类型：
--
作者：
Mitchell AJ;Lone AM;Tinoco AD;Saghatelian A
P物质（SP）是一种典型的神经肽，在疼痛和炎症中起作用。许多机制调节内源性SP水平，包括SP mRNA的差异表达和SP从神经元的受控分泌。长期以来，人们一直怀疑蛋白水解调节细胞外SP浓度，但支持这一假设的数据很少。在这里，我们提供的证据表明，蛋白水解控制SP水平在脊髓。使用肽组学检测和定量内源性SP片段，我们确定了SP的第九个残基的C-末端侧的主要SP裂解位点。如果阻断此途径增加SP水平，则蛋白水解控制SP浓度。我们使用脊髓裂解物作为内源性代谢环境的代表进行了靶向化学筛选，并将GM 6001（加拉定，伊洛马司他）鉴定为组织中存在的SP 1-9产生活性的有效抑制剂。给小鼠施用GM 6001导致脊髓SP水平增加超过三倍，这验证了蛋白水解控制生理SP水平的假设。
Substance P (SP) is a prototypical neuropeptide with roles in pain and inflammation. Numerous mechanisms regulate endogenous SP levels, including the differential expression of SP mRNA and the controlled secretion of SP from neurons. Proteolysis has long been suspected to regulate extracellular SP concentrations but data in support of this hypothesis is scarce. Here, we provide evidence that proteolysis controls SP levels in the spinal cord. Using peptidomics to detect and quantify endogenous SP fragments, we identify the primary SP cleavage site as the C-terminal side of the ninth residue of SP. If blocking this pathway increases SP levels, then proteolysis controls SP concentration. We performed a targeted chemical screen using spinal cord lysates as a proxy for the endogenous metabolic environment and identified GM6001 (galardin, ilomastat) as a potent inhibitor of the SP 1–9-producing activity present in the tissue. Administration of GM6001 to mice results in a greater-than-three-fold increase in the spinal cord levels of SP, which validates the hypothesis that proteolysis controls physiological SP levels.