Circadian clock gene expression in bone marrow derived mast cells and effects on FcϵRI expression (86.12)

Abstract

Abstract Many functions in the immune system are associated with time-of-day. For instance, blood histamine levels in mastocytosis patients display a diurnal variation. In addition, pulmonary function and inflammation in patients with nocturnal asthma is more severe during the night. However, it is largely unknown if local circadian clocks in immune cells directly control physiological outcomes. We hypothesized that a circadian clock in murine bone marrow derived mast cells (BMMCs) modulates their activation in vitro. Mature BMMCs were synchronized with serum rich media (50% horse serum). Total RNA was harvested at 4 hour intervals for 72 hours following synchronization and expression of circadian genes (mPer1, mPer2, Bmal1, Rev-erbα, and Dbp) and fcer1a were amplified by qPCR. The surface expression of FcϵRIα was analyzed by flow cytometry every 4 hours for 72 hours following synchronization. Serum shock induced rhythmic expression of circadian genes (mPer2, Bmal1, Rev-erbα, and Dbp) with a mean period of 25.9 hours in BMMCs. The expression of fcer1a gene and FcϵRIα protein displayed expression changes following serum shock with mean periods of 26.3 and 28.6 hours respectively as calculated by Single Cosinor Time Series Analysis. These findings demonstrate that BMMCs express circadian clock genes and FcϵRI expression is modulated by synchronization with serum rich media. Serum shock of BMMCs may provide an in vitro model to study the circadian biology of allergic disease.