Allergy and Immunology Research Project Team, Nihon University School of Medicine, Tokyo, Japan; Department of Dermatology, Nihon University School of Medicine, Tokyo, Japan; Center for Allergy, Nihon University Itabashi Hospital, Tokyo, Japan.
Allergy and Immunology Research Project Team, Nihon University School of Medicine, Tokyo, Japan; Department of Respiratory Medicine, Nihon University School of Medicine, Tokyo, Japan; Center for Allergy, Nihon University Itabashi Hospital, Tokyo, Japan.
Allergol Int. 2021 Oct;70(4):480-488. doi: 10.1016/j.alit.2021.05.002. Epub 2021 Jun 3.
We previously reported upregulation of expression of Mas-related G protein-coupled receptor X2 (MRGPRX2) on mast cells (MCs) in the skin of patients with severe chronic spontaneous urticaria (CSU). Serum levels of substance P (SP) were reportedly significantly elevated, in correlation with the severity of CSU. Hemokinin-1 (HK-1) reportedly induced histamine release from LAD2 cells via MRGPRX2. We aimed to investigate HK-1's role in CSU.
The concentrations of HK-1 and SP were measured using ELISAs. Skin- and synovium-derived cultured MCs were generated by culturing dispersed skin and synovial cells, respectively, with stem cell factor. MRGPRX2 expression in the MCs was reduced using a lentiviral shRNA silencing technique.
Anti-SP Ab used in the SP ELISA showed 100% cross-reactivity to HK-1, but anti-HK-1 Ab showed 0% cross-reactivity to SP. The serum level of HK-1 was significantly lower in patients with CSU (n = 151) than in non-atopic healthy control (NC) subjects (n = 114). The EC of histamine release from MCs induced by HK-1 (5056 nM) was 12-fold higher than by SP (426 nM). Brief pretreatment of MCs with HK-1 at concentrations of 3.0-10 μM significantly reduced histamine release by 0.1 μM SP. However, brief incubation of MCs with HK-1 did not elicit rapid MRGPRX2 internalization.
In NC subjects, high HK-1 concentrations may desensitize MGRPRX2-mediated MC activation, thereby preventing MC degranulation by SP.
我们之前报道过，在严重慢性自发性荨麻疹（CSU）患者的皮肤中，肥大细胞（MCs）上 Mas 相关 G 蛋白偶联受体 X2（MRGPRX2）的表达上调。据报道，血清中 P 物质（SP）的水平显著升高，与 CSU 的严重程度相关。据报道，血激肽-1（HK-1）通过 MRGPRX2 诱导 LAD2 细胞释放组胺。我们旨在研究 HK-1 在 CSU 中的作用。
使用 ELISA 测量 HK-1 和 SP 的浓度。通过分别用干细胞因子培养分散的皮肤和滑膜细胞，生成皮肤和滑膜来源的培养 MC。使用慢病毒 shRNA 沉默技术降低 MC 中的 MRGPRX2 表达。
用于 SP ELISA 的抗 SP Ab 对 HK-1 表现出 100%的交叉反应性，但抗 HK-1 Ab 对 SP 没有表现出 0%的交叉反应性。CSU 患者（n=151）的血清 HK-1 水平明显低于非特应性健康对照（NC）受试者（n=114）。HK-1 诱导 MC 释放组胺的 EC50（5056 nM）是 SP（426 nM）的 12 倍。HK-1 在 3.0-10 μM 浓度下短暂预处理 MC 可显著降低 0.1 μM SP 引起的组胺释放。然而，HK-1 短暂孵育 MC 不会引起 MRGPRX2 快速内化。
在 NC 受试者中，高浓度的 HK-1 可能使 MRGPRX2 介导的 MC 激活脱敏，从而防止 SP 引起 MC 脱颗粒。
