MrgX2 is a promiscuous receptor for basic peptides causing mast cell pseudo‐allergic and anaphylactoid reactions

Abstract

Activation of MrgX2, an orphan G protein‐coupled receptor expressed on mast cells, leads to degranulation and histamine release. Human MrgX2 binds promiscuously to structurally diverse peptides and small molecules that tend to have basic properties (basic secretagogues), resulting in acute histamine‐like adverse drug reactions of injected therapeutic agents. We set out to identify MrgX2 orthologues from other mammalian species used in nonclinical stages of drug development. Previously, the only known orthologue of human MrgX2 was from mouse, encoded by Mrgprb2. MrgX2 genes of rat, dog (beagle), minipig, pig, and Rhesus and cynomolgus monkey were identified by bioinformatic approaches and verified by their ability to mediate calcium mobilization in transfected cells in response to the classical MrgX2 agonist, compound 48/80. The peptide GSK3212448 is an inhibitor of the PRC2 epigenetic regulator that caused profound anaphylactoid reactions upon intravenous infusion to rat. We showed GSK3212448 to be a potent MrgX2 agonist particularly at rat MrgX2. We screened sets of drug‐like molecules and peptides to confirm the highly promiscuous nature of MrgX2. Approximately 20% of drug‐like molecules activated MrgX2 (pEC50 ranging from 4.5 to 6), with the principle determinant being basicity. All peptides tested of net charge +3 or greater exhibited agonist activity, including the cell penetrating peptides polyarginine (acetyl‐Arg9‐amide) and TAT (49‐60), a fragment of HIV‐1 TAT protein. Finally, we showed that the glycopeptide antibiotic vancomycin, which is associated with clinical pseudo‐allergic reactions known as red man syndrome, is an agonist of MrgX2.

Identification of the dog orthologue of human MAS-related G protein coupled receptor X2 (MRGPRX2) essential for drug-induced pseudo-allergic reactions

“…Consistent with their research 24 , we also confirmed that compound 48/80 activated MRGPRX2, but not MRGPRD, F, and G, suggesting that dog MRGPRX2 expressed in canine CTMC is the functional orthologue of human MRGPRX2. In human MRGPRX2-expressing cells, the EC 50 of certain drugs, such as compound 48/80, somewhat varied among the facilities 11,12,24 . This might have resulted from the difference in the host cells used, transfection methods, and co-expressed Gα proteins.…”

“…More recently, Grimes et al reported that compound 48/80 and several types of peptides activated dog MRGPRX2 24 . Consistent with their research 24 , we also confirmed that compound 48/80 activated MRGPRX2, but not MRGPRD, F, and G, suggesting that dog MRGPRX2 expressed in canine CTMC is the functional orthologue of human MRGPRX2. In human MRGPRX2-expressing cells, the EC 50 of certain drugs, such as compound 48/80, somewhat varied among the facilities 11,12,24 .…”

“…In dogs, MRGPRA, C, D, E, F, G, and H, in addition to X2, have been identified so far 22,23 , and among these genes, a total of four genes encoding MRGPR proteins (D, F, G, and X2) have been listed in the National Center for Biotechnology Information (NCBI). More recently, Grimes et al have shown that U2OS cells expressing beagle dog MRGPRX2 responded to compound 48/80 and various peptidergic drugs 24 . However, the localisation and physiological function of dog MRGPR family genes, including MRGPRX2, remain largely unknown.…”

Protective Effect of Genistein against Compound 48/80 Induced Anaphylactoid Shock via Inhibiting MAS Related G Protein-Coupled Receptor X2 (MRGPRX2)

“…Human MRGPRX2 (mouse orthologue MrgprB2) is a Class A orphan GPCR expressed on primates' mast cells [16]. Human MRGPRX2 binds promiscuously to structurally diverse peptides and small molecules that tend to have basic properties (basic secretagogues), resulting in acute histamine-like adverse drug reactions [35].…”

Osthole, a Natural Plant Derivative Inhibits MRGPRX2 Induced Mast Cell Responses

“…This receptor is expressed on connective tissue-type mast cells in the skin (5) and lungs (6). Interestingly, unlike other GPCRs, MRGPRX2 binds to multiple ligands and is potently activated by small cationic molecules and peptides that have amphipathic properties; therefore, this receptor can elicit responses to a wide variety of endogenous and exogenous ligands (7,8). As a result, MRGPRX2 is responsible for mediating mast cell anaphylactic and pseudo-allergic reactions to several US Food and Drug Administration (FDA)-approved drugs (3,(9)(10)(11)(12)(13)(14) and has been implicated in the pathology of chronic inflammatory diseases such as asthma (6), rosacea (15), and urticaria (5).…”