Structure-activity relationships for a series of small-molecule thiophenes resulted in potent and selective antagonism of human Complement C3a receptor. The compounds are about 100-fold more potent than the most reported antagonist SB290157. A new compound JR14a was among the most potent of the new antagonists in vitro, assessed by (a) inhibition of intracellular calcium release (IC50 10 nM) induced in human monocyte-derived macrophages by 100 nM C3a, (b) inhibition of β-hexosaminidase secretion (IC50 8 nM) from human LAD2 mast cells degranulated by 100 nM C3a, and (c) selectivity for human C3aR over C5aR. JR14a was metabolically stable in rat plasma and in rat liver microsomes and efficacious in rats when given orally to suppress rat paw inflammation, macrophage and mast cell activation, and histopathology induced by intraplantar paw administration of a C3aR agonist. Potent C3aR antagonists are now available for interrogating C3a receptor activation and suppressing C3aR-mediated inflammation in mammalian physiology and disease.

中文翻译：

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具有抗炎活性的人补体C3a受体的强力噻吩拮抗剂。

一系列小分子噻吩的结构活性关系导致人类补体C3a受体的有效和选择性拮抗作用。该化合物的功效比最报道的拮抗剂SB290157强约100倍。一种新的化合物JR14a在体外是最有效的新拮抗剂之一，其评估方法是（a）100 nM C3a抑制人单核细胞衍生的巨噬细胞诱导的细胞内钙释放（IC50 10 nM），（b）抑制β-人LAD2肥大细胞中的己糖胺酶分泌（IC50 8 nM）脱颗粒100 nM C3a，以及（c）对人C3aR的选择性高于C5aR。JR14a在大鼠血浆和大鼠肝微粒体中代谢稳定，在口服抑制大鼠爪发炎，巨噬细胞和肥大细胞活化方面有效，足底内施用C3aR激动剂引起的组织病理学改变。现在可以使用有效的C3aR拮抗剂来研究C3aR受体的活化并抑制C3aR介导的哺乳动物生理和疾病炎症。