Initial MCs activation disappeared with decreased MrgprB2
expression after tacrolimus long-term treatment
To mimic tacrolimus clinical long-term use, 0.03% tacrolimus cream were
applied on dorsal skin of mice twice per day. Strikingly, the earlier
irritant manifestations (scratching and inflammatory cells infiltration)
fade away with no skin IgE level change (Figure 6A, B and C). The levels
of skin TNF-α, MCP-1, IL-8 and tryptase on day 7 and 11 are with no
significant difference in the absence of additional C48/80 stimulation
(Figure 6D). To assess the status of MC at this time, avidin staining
was used, which showed no remarkable distinct in MCs infiltration and
degranulation compared to control group (Figure 6E). Surprisingly, skin
MrgprB2 expression was massively downregulated after 7-day and 11-day
tacrolimus topical use in vitro (Figure 7F). Hence, we speculated
that suppressed MrgprB2 expression may be involved in disappearance of
initial MCs stimulation after longer tacrolimus treatment.