Department of Pharmacology, University of Cambridge, Cambridge CB2 1PD, United Kingdom.
Institute of Physiology and Pathophysiology, University of Erlangen-Nuremberg, 91052 Erlangen, Germany.
J Neurosci. 2013 May 22;33(21):9184-9193. doi: 10.1523/JNEUROSCI.4991-12.2013.
Inflammation causes hyperalgesia, an enhanced sensitivity to noxious stimuli. Transient receptor potential vanilloid 1 (TRPV1), a thermo-TRP ion channel activated by painful levels of heat, is an important contributor because hyperalgesia is reduced when TRPV1 is either genetically deleted or pharmacologically blocked. Inflammatory mediators such as prostaglandin-E2 or bradykinin cause hyperalgesia by activating cellular kinases that phosphorylate TRPV1, a process that has recently been shown to rely on a scaffolding protein, AKAP79, to target the kinases to TRPV1. Here we use Förster resonance energy transfer, immunoprecipitation, and TRPV1 membrane trafficking experiments to identify a key region on AKAP79, between amino acids 326-336, which is responsible for its interaction with TRPV1. A peptide identical to this domain inhibited sensitization of TRPV1 in vitro, and when covalently linked to a TAT peptide to promote uptake across the cell membrane the peptide inhibited in vivo inflammatory hyperalgesia in mice. Critically, it did so without affecting pain thresholds in the absence of inflammation. These results suggest that antagonizing the TRPV1-AKAP79 interaction will be a useful strategy for inhibiting inflammatory hyperalgesia.
炎症导致痛觉过敏，即对有害刺激的敏感性增强。瞬时受体电位香草素 1（TRPV1）是一种热敏型 TRP 离子通道，对疼痛程度的热刺激敏感，是导致痛觉过敏的重要因素，因为当 TRPV1 基因缺失或被药物阻断时，痛觉过敏会减轻。炎症介质，如前列腺素 E2 或缓激肽，通过激活细胞激酶来导致痛觉过敏，这些激酶会磷酸化 TRPV1，最近的研究表明，这一过程依赖于一种支架蛋白 AKAP79，将激酶靶向 TRPV1。在这里，我们使用荧光共振能量转移、免疫沉淀和 TRPV1 膜转运实验，确定了 AKAP79 上一个关键区域，即 326-336 位氨基酸，该区域负责与 TRPV1 相互作用。与该结构域相同的肽在体外抑制 TRPV1 的敏化作用，当与 TAT 肽共价连接以促进跨细胞膜摄取时，该肽在体内抑制小鼠的炎症性痛觉过敏。关键的是，在没有炎症的情况下，它不会影响疼痛阈值。这些结果表明，拮抗 TRPV1-AKAP79 相互作用将是抑制炎症性痛觉过敏的一种有效策略。
