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@ARTICLE{AlHamwi:300596,
author = {G. Al Hamwi and M. W. Alnouri and S. Verdonck and P.
Leonczak and S. Chaki and S. Frischbutter and P. Kolkhir and
M. Matthey and C. Kopp and M. Bednarski and Y. K. Riedel and
D. Marx and S. Clemens and V. Namasivayam and S. Gattner and
D. Thimm and K. Sylvester and K. Wolf$^*$ and A. E. Kremer
and S. De Jonghe and D. Wenzel and M. Kotańska and H. Ali
and P. Herdewijn and C. E. Müller},
title = {{S}ubnanomolar {MAS}-related {G} protein-coupled
receptor-{X}2/{B}2 antagonists with efficacy in human mast
cells and disease models.},
journal = {Signal transduction and targeted therapy},
volume = {10},
number = {1},
issn = {2095-9907},
address = {London},
publisher = {Macmillan Publishers, part of Springer Nature},
reportid = {DKFZ-2025-00810},
pages = {128},
year = {2025},
abstract = {The MAS-related G protein-coupled receptor-X2 (MRGPRX2), an
orphan receptor expressed on mast cells (MCs), is
upregulated upon inflammation and induces hypersensitivity
and inflammatory diseases. In contrast to the large number
of MRGPRX2 agonists, only a few antagonists have been
described, and no optimization has been reported to improve
potency, selectivity, and drug-like properties. Antagonists
with ancillary inhibition of the putative mouse ortholog
MRGPRB2 have not been described. Here, we present a
multi-disciplinary approach involving chemistry, biology,
and computational science, resulting in the development of a
small-molecule MRGPRX2 antagonist (PSB-172656,
3-ethyl-7,8-difluoro-2-isopropylbenzo[4,5]imidazo [1,2-a]
pyrimidin-4(1H)-one) based on a fragment screening hit. The
compound exhibits metabolic stability, low cytotoxicity, and
competitive blockade of MRGPRX2 activation induced by a
diverse range of agonists. It displays subnanomolar potency
in Ca2+ mobilization assays (Ki value 0.142 nM) and was
found to block MRGPRX2-mediated Gαq and Gαi1 dissociation,
in addition to β-arrestin-2 recruitment. PSB-172656 is
selective for MRGPRX2 versus all other MRGPRX subtypes. Its
effect on MCs was confirmed in cell lines, including rat
basophilic leukemia cells (RBL-2H3) recombinantly expressing
human MRGPRX2, human Laboratory of Allergic Diseases 2
(LAD2) MCs, and native human skin MCs. PSB-172656 was found
to additionally block the putative mouse ortholog of
MRGPRX2, MRGPRB2, as determined in Ca2+ mobilization assays
(Ki 0.302 nM), and to prevent mouse tracheal contractions,
local allergic reactions, and systemic anaphylactic
symptoms. PSB-172656 constitutes a unique pharmacological
tool and has the potential to be developed as a drug for
mast cell-mediated hypersensitivity reactions and chronic
inflammatory diseases, addressing a huge unmet medical
need.},
keywords = {Mast Cells: drug effects / Mast Cells: metabolism / Mast
Cells: pathology / Humans / Receptors, G-Protein-Coupled:
antagonists $\&$ inhibitors / Receptors, G-Protein-Coupled:
genetics / Animals / Mice / Receptors, Neuropeptide:
antagonists $\&$ inhibitors / Receptors, Neuropeptide:
genetics / Nerve Tissue Proteins: antagonists $\&$
inhibitors / Nerve Tissue Proteins: genetics / beta-Arrestin
2: genetics / Disease Models, Animal / Receptors,
G-Protein-Coupled (NLM Chemicals) / MRGPRX2 protein, human
(NLM Chemicals) / Receptors, Neuropeptide (NLM Chemicals) /
Nerve Tissue Proteins (NLM Chemicals) / beta-Arrestin 2 (NLM
Chemicals) / Mrgprb2 protein, mouse (NLM Chemicals) / ARRB2
protein, human (NLM Chemicals)},
cin = {D190},
ddc = {610},
cid = {I:(DE-He78)D190-20160331},
pnm = {314 - Immunologie und Krebs (POF4-314)},
pid = {G:(DE-HGF)POF4-314},
typ = {PUB:(DE-HGF)16},
pubmed = {pmid:40254631},
doi = {10.1038/s41392-025-02209-8},
url = {https://inrepo02.dkfz.de/record/300596},
}