Murepavadin, a Small Molecule Host Defense Peptide Mimetic, Activates Mast Cells via MRGPRX2 and MrgprB2

Amponnawarat, Aetas; Ayudhya, Chalatip Chompunud Na; Ali, Hydar

doi:10.3389/fimmu.2021.689410

Cited by 12 publications

(12 citation statements)

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“…Cells were isolated from peritoneal lavages of WT and MrgprB2 −/− mice and were cultured for 4–8 weeks in complete Roswell Park Memorial Institute 1640 Medium (RPMI 1640) containing 10% FCS, penicillin (100 IU/ml), streptomycin (100 mg/ml), recombinant mouse IL-3 (10 ng/ml) and SCF (30 ng/ml). Cells were used within 4–8 weeks ( 27 , 35 ). All cell cultures were kept at a 37°C incubator with 5% CO 2 .…”

Section: Methodsmentioning

confidence: 99%

Inhibition of MRGPRX2 but not FcεRI or MrgprB2-mediated mast cell degranulation by a small molecule inverse receptor agonist

et al. 2022

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Mas-related G protein-coupled receptor-X2 (MRGPRX2) expressed on mast cells (MCs) contributes to hypersensitivity reactions to cationic US-Food and Drug Administration (FDA) approved drugs such as the neuromuscular blocking agent, rocuronium. In addition, activation of MRGPRX2 by the neuropeptide substance P (SP) and the pro-adrenomedullin peptide (PAMP-12) is associated with a variety of cutaneous conditions such as neurogenic inflammation, pain, atopic dermatitis, urticaria, and itch. Thus, small molecules aimed at blocking MRGPRX2 constitute potential options for modulating IgE-independent MC-mediated disorders. Two inverse MRGPRX2 agonists, named C9 and C9-6, have recently been identified, which inhibit basal G protein activation and agonist-induced calcium mobilization in transfected HEK293 cells. Substance P serves as a balanced agonist for MRGPRX2 whereby it activates both G protein-mediated degranulation and β-arrestin-mediated receptor internalization. The purpose of this study was to determine if C9 blocks MRGPRX2’s G protein and β-arrestin-mediated signaling and to determine its specificity. We found that C9, but not its inactive analog C7, inhibited degranulation in RBL-2H3 cells stably expressing MRGPRX2 in response to SP, PAMP-12 and rocuronium with an IC50 value of ~300 nM. C9 also inhibited degranulation as measured by cell surface expression of CD63, CD107a and β-hexosaminidase release in LAD2 cells and human skin-derived MCs in response to SP but not the anaphylatoxin, C3a or FcϵRI-aggregation. Furthermore, C9 inhibited β-arrestin recruitment and MRGPRX2 internalization in response to SP and PAMP-12. We found that a G protein-coupling defective missense MRGPRX2 variant (V282M) displays constitutive activity for β-arrestin recruitment, and that this response was significantly inhibited by C9. Rocuronium, SP and PAMP-12 caused degranulation in mouse peritoneal MCs and these responses were abolished in the absence of MrgprB2 or cells treated with pertussis toxin but C9 had no effect. These findings suggest that C9 could provide an important framework for developing novel therapeutic approaches for the treatment of IgE-independent MC-mediated drug hypersensitivity and cutaneous disorders.

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Section: Methodsmentioning

confidence: 99%

Inhibition of MRGPRX2 but not FcεRI or MrgprB2-mediated mast cell degranulation by a small molecule inverse receptor agonist

et al. 2022

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“…Several reports suggest that SSRI inhibitors such as paroxetine have antimicrobial activity and can be a promising alternative for treating bacterial infection ( 33 , 46 , 47 ). In addition to direct antimicrobial activity, antimicrobial peptides can activate MCs to harness their immunomodulatory properties ( 26 , 48 – 50 ). Recent evidence suggests that this immunomodulatory property is mediated via activation of MRGPRB2 and it plays a crucial role in host defense and clearing antibacterial infection ( 19 , 20 , 22 , 26 ).…”

Section: Discussionmentioning

confidence: 99%

“…In addition to direct antimicrobial activity, antimicrobial peptides can activate MCs to harness their immunomodulatory properties ( 26 , 48 – 50 ). Recent evidence suggests that this immunomodulatory property is mediated via activation of MRGPRB2 and it plays a crucial role in host defense and clearing antibacterial infection ( 19 , 20 , 22 , 26 ). A surprising observation of our study was that paroxetine evoked an acute inflammatory response by causing increased cutaneous vascular permeability and neutrophil recruitment via MRGPRB2.…”

Section: Discussionmentioning

confidence: 99%

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GRK2 inhibitors, paroxetine and CCG258747, attenuate IgE-mediated anaphylaxis but activate mast cells via MRGPRX2 and MRGPRB2

et al. 2022

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G protein-coupled receptor (GPCR) kinase 2 (GRK2), which phosphorylates agonist-occupied GPCRs to promote their desensitization, has been investigated as an attractive therapeutic target for cardiovascular and metabolic diseases. Several GRK2-targeted inhibition strategies have been reported including the use of direct pharmacological inhibitors such as paroxetine (a widely prescribed antidepressant) and its analogs such as compound CCG258747. Cross-linking of high affinity IgE receptor (FcϵRI) on mast cells (MCs) and the resulting degranulation causes anaphylaxis and allergic asthma. Using gene silencing strategy, we recently showed that GRK2 contributes to FcεRI signaling and MC degranulation. The purpose of this study was to determine if the GRK2 inhibitors paroxetine and CCG258747 modulate FcεRI-mediated MC responses in vitro and in vivo. Utilizing rat basophilic leukemia (RBL-2H3) cells and primary mouse lung MCs (LMCs), we found that paroxetine and CCG258747 inhibit FcϵRI-mediated calcium mobilization and degranulation. Furthermore, intravenous administration of paroxetine and CCG258747 in mice resulted in substantial reduction of IgE-mediated passive cutaneous anaphylaxis. Unlike LMCs, human cutaneous MCs abundantly express a novel GPCR known as MRGPRX2 (mouse; MRGPRB2). We found that in contrast to their inhibitory effects on FcεRI-mediated MC responses, both paroxetine and CCG258747 induce calcium mobilization and degranulation in RBL-2H3 cells stably expressing MRGPRX2 but not in untransfected cells. Furthermore, paroxetine and CCG258747 induced degranulation in peritoneal MCs from Wild-type (WT) mice in vitro and caused increased cutaneous vascular permeability in vivo, but these responses were substantially reduced in Mrgprb2−/− mice. Additionally, upon intradermal injection, paroxetine also induced neutrophil recruitment in WT but not Mrgprb2−/− mice. These findings suggest that in addition to their potential therapeutic utility against cardiovascular and metabolic disorders, paroxetine-based GRK2-inhibitors may serve to modulate IgE-mediated anaphylaxis and to enhance cutaneous host defense by harnessing MC’s immunomodulatory property through the activation of MRGPRX2/MRGPRB2.

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“…To minimize these disadvantages, HDP sequences have been studied in the presence of, e.g., red blood cells to take into account physiological salt conditions [ 88 , 93 ]. In addition, small molecule HDP mimetics have been investigated [ 94 , 95 ]. Finally, a variety of chemical modifications and delivery vehicles have been harnessed.…”

Section: Host Defense Peptidesmentioning

confidence: 99%

Host Defense Peptides: Dual Antimicrobial and Immunomodulatory Action

Drayton

Deisinger

Ludwig

et al. 2021

IJMS

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The rapid rise of multidrug-resistant (MDR) bacteria has once again caused bacterial infections to become a global health concern. Antimicrobial peptides (AMPs), also known as host defense peptides (HDPs), offer a viable solution to these pathogens due to their diverse mechanisms of actions, which include direct killing as well as immunomodulatory properties (e.g., anti-inflammatory activity). HDPs may hence provide a more robust treatment of bacterial infections. In this review, the advent of and the mechanisms that lead to antibiotic resistance will be described. HDP mechanisms of antibacterial and immunomodulatory action will be presented, with specific examples of how the HDP aurein 2.2 and a few of its derivatives, namely peptide 73 and cG4L73, function. Finally, resistance that may arise from a broader use of HDPs in a clinical setting and methods to improve biocompatibility will be briefly discussed.

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Murepavadin, a Small Molecule Host Defense Peptide Mimetic, Activates Mast Cells via MRGPRX2 and MrgprB2

Cited by 12 publications

References 58 publications

Inhibition of MRGPRX2 but not FcεRI or MrgprB2-mediated mast cell degranulation by a small molecule inverse receptor agonist

Inhibition of MRGPRX2 but not FcεRI or MrgprB2-mediated mast cell degranulation by a small molecule inverse receptor agonist

GRK2 inhibitors, paroxetine and CCG258747, attenuate IgE-mediated anaphylaxis but activate mast cells via MRGPRX2 and MRGPRB2

Host Defense Peptides: Dual Antimicrobial and Immunomodulatory Action

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