Abstract：
BACKGROUND: Mas-related G-protein coupled receptor X2 (MRGPRX2) is a promiscuous receptor on mast cells that mediates IgE-independent degranulation and has been implicated in multiple mast cell-mediated disorders, including chronic urticaria, atopic dermatitis, and pain disorders. Although it is a promising therapeutic target, few potent, selective, small molecule antagonists have been identified, and functional effects of human MRGPRX2 inhibition have not been evaluated in vivo.
OBJECTIVE: We identified and characterized novel, potent, and selective orally active small molecule MRGPRX2 antagonists for potential treatment of mast cell-mediated disease.
METHODS: Antagonists were identified using multiple functional assays in cell lines overexpressing human MRGPRX2, LAD2 mast cells, human peripheral stem cell-derived mast cells, and isolated skin mast cells. Skin mast cell degranulation was evaluated in Mrgprb2em(-/-) knockout (KO) and Mrgprb2em(MRGPRX2) transgenic human MRGPRX2 knock-in (KI) mice by assessment of agonist-induced skin vascular permeability. Ex vivo skin mast cell degranulation and associated histamine release was evaluated by microdialysis of human skin tissue samples.
RESULTS: MRGPRX2 antagonists potently inhibited agonist-induced MRGPRX2 activation and mast cell degranulation in all mast cell types tested, in an IgE-independent manner. Orally administered MRGPRX2 antagonists also inhibited agonist-induced degranulation and resulting vascular permeability in MRGPRX2 KI mice. In addition, antagonist treatment dose dependently inhibited agonist-induced degranulation in ex vivo human skin.
CONCLUSIONS: MRGPRX2 small molecule antagonists potently inhibited agonist-induced mast cell degranulation in vitro and in vivo as well as ex vivo in human skin, supporting potential therapeutic utility as a novel treatment for multiple human diseases involving clinically relevant mast cell activation.
OBJECTIVE: We identified and characterized novel, potent, and selective orally active small molecule MRGPRX2 antagonists for potential treatment of mast cell-mediated disease.
METHODS: Antagonists were identified using multiple functional assays in cell lines overexpressing human MRGPRX2, LAD2 mast cells, human peripheral stem cell-derived mast cells, and isolated skin mast cells. Skin mast cell degranulation was evaluated in Mrgprb2em(-/-) knockout (KO) and Mrgprb2em(MRGPRX2) transgenic human MRGPRX2 knock-in (KI) mice by assessment of agonist-induced skin vascular permeability. Ex vivo skin mast cell degranulation and associated histamine release was evaluated by microdialysis of human skin tissue samples.
RESULTS: MRGPRX2 antagonists potently inhibited agonist-induced MRGPRX2 activation and mast cell degranulation in all mast cell types tested, in an IgE-independent manner. Orally administered MRGPRX2 antagonists also inhibited agonist-induced degranulation and resulting vascular permeability in MRGPRX2 KI mice. In addition, antagonist treatment dose dependently inhibited agonist-induced degranulation in ex vivo human skin.
CONCLUSIONS: MRGPRX2 small molecule antagonists potently inhibited agonist-induced mast cell degranulation in vitro and in vivo as well as ex vivo in human skin, supporting potential therapeutic utility as a novel treatment for multiple human diseases involving clinically relevant mast cell activation.
摘要：
背景：与Mas相关的G蛋白偶联受体X2（MRGPRX2）是肥大细胞上的混杂受体，可介导不依赖IgE的脱颗粒，并与多种肥大细胞介导的疾病有关，包括慢性荨麻疹,特应性皮炎,和疼痛紊乱。虽然它是一个很有前途的治疗靶点，很少有效，选择性,已经确定了小分子拮抗剂，和人MRGPRX2抑制的功能作用尚未在体内评估。
目的：我们鉴定并表征了新的，强力，和选择性口服活性小分子MRGPRX2拮抗剂用于肥大细胞介导的疾病的潜在治疗。
方法：在过表达人MRGPRX2，LAD2肥大细胞的细胞系中使用多功能测定法鉴定拮抗剂，人类外周干细胞来源的肥大细胞，和分离的皮肤肥大细胞。通过评估激动剂诱导的皮肤血管通透性，在Mrgprb2em（-/-）敲除（KO）和Mrgprb2em（MRGPRX2）转基因人MRGPRX2敲入（KI）小鼠中评估了皮肤肥大细胞脱颗粒。通过人皮肤组织样品的微透析评估离体皮肤肥大细胞脱粒和相关的组胺释放。
结果：MRGPRX2拮抗剂可有效抑制所有受试肥大细胞类型中激动剂诱导的MRGPRX2活化和肥大细胞脱颗粒，以不依赖IgE的方式。口服MRGPRX2拮抗剂还抑制了MRGPRX2KI小鼠中激动剂诱导的脱颗粒和导致的血管通透性。此外,拮抗剂治疗剂量依赖性地抑制离体人皮肤中激动剂诱导的脱颗粒。
结论：MRGPRX2小分子拮抗剂可有效抑制激动剂诱导的肥大细胞体外和体内以及离体皮肤脱粒，支持作为涉及临床相关肥大细胞激活的多种人类疾病的新型治疗方法的潜在治疗用途。
目的：我们鉴定并表征了新的，强力，和选择性口服活性小分子MRGPRX2拮抗剂用于肥大细胞介导的疾病的潜在治疗。
方法：在过表达人MRGPRX2，LAD2肥大细胞的细胞系中使用多功能测定法鉴定拮抗剂，人类外周干细胞来源的肥大细胞，和分离的皮肤肥大细胞。通过评估激动剂诱导的皮肤血管通透性，在Mrgprb2em（-/-）敲除（KO）和Mrgprb2em（MRGPRX2）转基因人MRGPRX2敲入（KI）小鼠中评估了皮肤肥大细胞脱颗粒。通过人皮肤组织样品的微透析评估离体皮肤肥大细胞脱粒和相关的组胺释放。
结果：MRGPRX2拮抗剂可有效抑制所有受试肥大细胞类型中激动剂诱导的MRGPRX2活化和肥大细胞脱颗粒，以不依赖IgE的方式。口服MRGPRX2拮抗剂还抑制了MRGPRX2KI小鼠中激动剂诱导的脱颗粒和导致的血管通透性。此外,拮抗剂治疗剂量依赖性地抑制离体人皮肤中激动剂诱导的脱颗粒。
结论：MRGPRX2小分子拮抗剂可有效抑制激动剂诱导的肥大细胞体外和体内以及离体皮肤脱粒，支持作为涉及临床相关肥大细胞激活的多种人类疾病的新型治疗方法的潜在治疗用途。
