RESUMO
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.
Assuntos
Anafilaxia/induzido quimicamente , Mastócitos/efeitos dos fármacos , Proteínas do Tecido Nervoso/agonistas , Fragmentos de Peptídeos/efeitos adversos , Receptores Acoplados a Proteínas G/agonistas , Receptores de Neuropeptídeos/agonistas , Vancomicina/efeitos adversos , Anafilaxia/imunologia , Animais , Degranulação Celular/efeitos dos fármacos , Degranulação Celular/imunologia , Linhagem Celular Tumoral , Peptídeos Penetradores de Células/administração & dosagem , Peptídeos Penetradores de Células/efeitos adversos , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos/efeitos adversos , Células HEK293 , Histona-Lisina N-Metiltransferase/antagonistas & inibidores , Humanos , Mastócitos/imunologia , Mastócitos/metabolismo , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/imunologia , Proteínas do Tecido Nervoso/metabolismo , Fragmentos de Peptídeos/administração & dosagem , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/imunologia , Receptores Acoplados a Proteínas G/metabolismo , Receptores de Neuropeptídeos/genética , Receptores de Neuropeptídeos/imunologia , Receptores de Neuropeptídeos/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/metabolismo , Síndrome , Vancomicina/administração & dosagem , p-Metoxi-N-metilfenetilamina/farmacologiaRESUMO
Overexpression of ATAD2 (ATPase family, AAA domain containing 2) has been linked to disease severity and progression in a wide range of cancers, and is implicated in the regulation of several drivers of cancer growth. Little is known of the dependence of these effects upon the ATAD2 bromodomain, which has been categorized as among the least tractable of its class. The absence of any potent, selective inhibitors limits clear understanding of the therapeutic potential of the bromodomain. Here, we describe the discovery of a hit from a fragment-based targeted array. Optimization of this produced the first known micromolar inhibitors of the ATAD2 bromodomain.