CCR1 expression and signal transduction by murine BMMC results in secretion of TNF-α, TGFβ-1 and IL-6

Abstract

Abstract Chemokine receptors (CCRs) are important co-stimulatory molecules found on many blood cells and associated with various diseases. The expression and function of CCRs on mast cells has been quite controversial. In this study, we report for the first time that murine bone marrow-derived mast cells (BMMC) express messenger RNA and protein for CCR1. BMMC cultured in the presence of murine recombinant stem cell factor and murine IL-3 expressed CCR1 after 5–6 weeks. We also report for the first time that mBMMCCCR1+ cells endogenously express neurokinin receptor-1 and intercellular adhesion molecule-1. To examine the activity of CCR1 on these BMMC, we simultaneously stimulated two receptors: CCR1 by its ligand macrophage inflammatory protein-1α and the IgE receptor FcεRI by antigen cross-linking. We found that co-stimulation enhanced BMMC degranulation compared with FcεRI stimulation alone, as assessed by β-hexosaminidase activity (85 versus 54%, P < 0.0001) and Ca2+ influx (223 versus 183 nM, P < 0.05). We also observed significant increases in mast cell secretion of key growth factors, cytokines and chemokine mediators upon CCR1–FcεRI co-stimulation. These factors include transforming growth factor β-1, tumor necrosis factor-α and the cytokine IL-6. Taken together, our data indicate that CCR1 plays a key role in BMMC function. These findings contribute to our understanding of mechanisms for immune cell trafficking during inflammation.