Panoply™ Human MRGPRX2 Knockdown Stable Cell Line

Patients may experience pseudoanaphylactic reactions when receiving muscle relaxants during perioperative anesthesia. These reactions can be life-threatening, particularly in children. Cisatracurium, a relatively new nonmuscle relaxant (NMBA), has been associated with bronchospasm and cardiovascular collapse. Here, researchers demonstrate that cisatracurium induces anaphylactic-like reactions in wild-type mice. However, cisatracurium did not induce similar phenomena in KitW-sh/W-sh mice. Furthermore, mice knocked out for the mast cell-associated G protein-coupled receptor B2 did not develop an inflammatory response after treatment with cisatracurium. Cisatracurium induced degranulation in LAD2 cells, leading to a dose-dependent release of β-hexosaminidase, histamine, and TNF-α. However, cisatracurium induced only low levels of these mediators in LAD2 cells transfected with MRGPRX2 siRNA. Cisatracurium also stimulated intracellular Ca2+ influx in MRGPRX2-HEK293 cells, compared to NC-HEK293 cells. Notably, no cytokine release was observed in LAD2 cells even after high-dose cisatracurium. Cisatracurium activates MRGPRX2 and triggers mast cell degranulation, thereby initiating an anaphylactoid response. Therefore, strategies targeting MRGPRX2 may be useful in blocking cisatracurium-induced anaphylactoid reactions.

Cisatracurium increased the intracellular Ca2+ concentration in HEK293 cells overexpressing MRGPRX2 but did not alter the intracellular Ca2+ concentration in HEK293 cells transfected with an empty plasmid (Figure 1A). siRNA was transfected into these cells to investigate the target of cisatracurium. MRGPRX2 was downregulated in LAD2 human mast cells transfected with siRNA, while LAD2 cells transfected with nonfunctional siRNA served as controls (Figure 1B and C). Thirty minutes after drug administration, the rate of β-hexosaminidase release and the amount of histamine released from LAD2 mast cells were measured (Figure 1D and E). At the same drug concentration, MRGPRX2-knockdown LAD2 cells released less β-hexosaminidase and histamine than NC LAD2 cells, and drug-induced degranulation was significantly reduced. Furthermore, cisatracurium-induced LAD2 cell release of pro-TNF-α was significantly higher than that in MRGPRX2-knockdown LAD2 cells (Figure 1F). Based on these results, cisatracurium induces degranulation via MRGPRX2.

Figure 1. Cisatracurium induces mast cell degranulation via MRGPRX2. (Che D, et al., 2018)