A Novel Cell Culture System to Improve MRGPRX2 Research in Human Skin Mast Cells.

BACKGROUND: MRGPRX2, a receptor central to mast cell (MC) activation and related skin diseases, is selectively expressed in skin MCs but downregulated during culture by stem cell factor (SCF) and interleukin-4 (IL-4). OBJECTIVE: To identify culture conditions that preserve MC viability while restoring MRGPRX2 expression and function. METHODS: Human skin MCs were cultured in standard or serum-free Accell medium (both with SCF). After 3 days, MRGPRX2 expression was assessed by flow cytometry, degranulation by mediator release assays, and signaling by Western blotting. RESULTS: Accell medium increased MRGPRX2 expression to ~1.7-fold and enhanced degranulation to Substance P and codeine. It also promoted stronger and more sustained ERK and AKT phosphorylation, while FcεRI-mediated responses were largely unaffected. CONCLUSION: Short-term incubation in serum-free Accell medium restores MRGPRX2 expression and signaling in cultured skin MCs without impairing viability. This simple adjustment yields a practical and reliable model for MRGPRX2-focused studies.