Characterisation of MRGPRX2+ mast cells in irritable bowel syndrome, 2025, Decraecker et al.

Characterisation of MRGPRX2+ mast cells in irritable bowel syndrome
Lisse Decraecker; María Cuende Estévez; Samuel Van Remoortel; Runze Quan; Nathalie Stakenborg; Zheng Wang; Elisabetta De Marco; Alexandre Denadai-Souza; Maria Francesca Viola; Sonia Garcia Caraballo; Stuart Brierley; Yasuhiro Tsukimi; Gareth Hicks; Wendy Winchester; Jill Wykosky; Andrea Fanjul; Tony Gibson; Mira Wouters; Pieter Vanden Berghe; Hind Hussein; Guy Boeckxstaens

BACKGROUND
Mast cell activation is an important driver of abdominal pain in irritable bowel syndrome (IBS). While evidence supports the role of IgE-mediated mast cell activation in visceral pain development in IBS, the role of pseudoallergic MRGPRX2-mediated mast cell activation in this process remains unknown.

OBJECTIVE
We investigated whether MRGPRX2-mediated mast cell activation plays a role in abdominal pain development in patients with IBS.

DESIGN
MRGPRX2 expression in mast cells and other immune cells was characterised across colon layers using flow cytometry. We evaluated whether MRGPRX2 agonists trigger mast cell degranulation and transient receptor potential vanilloid 1 (TRPV1) sensitisation in healthy human colonic submucosal plexus samples using live imaging. Rectal biopsies were then collected from patients with IBS and healthy volunteers (HV) and MRGPRX2+ mast cell frequency, MRGPRX2 expression per cell, mast cell degranulation kinetics in response to MRGPRX2 agonists, MRGPRX2 agonistic activity and presence of MRGPRX2 agonists in biopsy supernatants were assessed.

RESULTS
MRGPRX2+ mast cells are enriched in the submucosa and muscularis of the healthy human colon. MRGPRX2 agonists induce mast cell degranulation and TRPV1 sensitisation in the healthy colon submucosa. While the frequency of rectal MRGPRX2+ mast cells was unaltered in IBS, submucosal mast cells showed increased degranulation in response to MRGPRX2 agonists in IBS compared with HV. MRGPRX2 agonistic activity was increased in IBS rectal biopsy supernatant compared with HV, which was associated with increased levels of substance P.

CONCLUSION
The MRGPRX2 pathway is functionally upregulated in the colon of patients with IBS, supporting its role in abdominal pain in IBS.


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See also An interorgan neuroimmune circuit promotes visceral hypersensitivity (2025, Preprint: Research Square)