Protease-activated receptor 2 sensitizes the capsaicin receptor transient receptor potential vanilloid receptor 1 to induce hyperalgesia
Protease-activated receptor 2 sensitizes the capsaicin receptor transient receptor potential vanilloid receptor 1 to induce hyperalgesia
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DOI：
10.1523/jneurosci.5679-03.2004
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发表时间：
2004-05-05
影响因子：
5.3
通讯作者：
Bunnett, NW
中科院分区：
文献类型：
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作者：
Amadesi, S;Nie, JJ;Bunnett, NW
炎性蛋白酶(肥大细胞、类胰蛋白酶和胰蛋白酶)裂解脊髓传入神经元上的蛋白酶激活受体2(PAR(2))，导致持续性炎症和痛觉过敏，其机制尚不清楚。我们确定了瞬时受体电位香草酸受体1(TRPV1)是否参与了PAR(2)诱导的痛敏反应。免疫荧光法显示，PAR(2)与TRPV1在背根神经节(DRG)的中小直径神经元中共表达。PAR(2)激动剂增加培养的神经元内[Ca~(2+)]([Ca~(2+)](I))，PAR(2)反应神经元对TRPV1激动剂辣椒素也有反应，证实PAR(2)和TRPV1共表达。PAR(2)激动剂增强辣椒素诱导的人胚胎肾(HEK)细胞和DRG神经元[Ca~(2+)](I)升高，并增强辣椒素诱导的DRG神经元电流。磷脂酶C和蛋白激酶C(PKC)抑制剂可抑制PAR(2)对TRPV1介导的[Ca~(2+)](I)和TRPV1电流的敏化作用。激活PAR(2)或PKC可诱导HEK细胞中TRPV1的磷酸化，提示对该通道有直接调节作用。足底注射PAR(2)激动剂可引起持续性的热痛敏，这可通过拮抗或删除TRPV1来预防。同时注射非痛敏剂量的PAR(2)激动剂和辣椒素可引起痛敏反应，这种反应可被TRPV1基因缺失或PKC拮抗所抑制。PAR(2)的激活也增强了辣椒素诱导的P物质和降钙素基因相关肽从脊髓背角超融合节段释放出来，在那里它们介导了痛觉过敏。我们已经确定了一种新的机制，激活PAR(2)的蛋白酶通过PKC敏化TRPV1。PAR(2)、TRPV1或PKC的拮抗作用可消除蛋白水解酶诱导的热痛敏。
Inflammatory proteases (mast cell tryptase and trypsins) cleave protease-activated receptor 2 (PAR(2)) on spinal afferent neurons and cause persistent inflammation and hyperalgesia by unknown mechanisms. We determined whether transient receptor potential vanilloid receptor 1 (TRPV1), a cation channel activated by capsaicin, protons, and noxious heat, mediates PAR(2)-induced hyperalgesia. PAR(2) was coexpressed with TRPV1 in small- to medium-diameter neurons of the dorsal root ganglia (DRG), as determined by immunofluorescence. PAR(2) agonists increased intracellular [Ca2+] ([Ca2+](i)) in these neurons in culture, and PAR(2)-responsive neurons also responded to the TRPV1 agonist capsaicin, confirming coexpression of PAR(2) and TRPV1. PAR(2) agonists potentiated capsaicin-induced increases in [Ca2+](i) in TRPV1-transfected human embryonic kidney (HEK) cells and DRG neurons and potentiated capsaicin-induced currents in DRG neurons. Inhibitors of phospholipase C and protein kinase C (PKC) suppressed PAR(2)-induced sensitization of TRPV1-mediated changes in [Ca2+](i) and TRPV1 currents. Activation of PAR(2) or PKC induced phosphorylation of TRPV1 in HEK cells, suggesting a direct regulation of the channel. Intraplantar injection of a PAR(2) agonist caused persistent thermal hyperalgesia that was prevented by antagonism or deletion of TRPV1. Coinjection of nonhyperalgesic doses of PAR(2) agonist and capsaicin induced hyperalgesia that was inhibited by deletion of TRPV1 or antagonism of PKC. PAR(2) activation also potentiated capsaicin-induced release of substance P and calcitonin gene-related peptide from superfused segments of the dorsal horn of the spinal cord, where they mediate hyperalgesia. We have identified a novel mechanism by which proteases that activate PAR(2) sensitize TRPV1 through PKC. Antagonism of PAR(2), TRPV1, or PKC may abrogate protease-induced thermal hyperalgesia.