The incapability of interleukin-4 to induce AP-1 activity in murine mast cells

Transcription Factors in the Development and Pro-Allergic Function of Mast Cells

Mast cells (MCs) are innate immune cells of hematopoietic origin localized in the mucosal tissues of the body and are broadly implicated in the pathogenesis of allergic inflammation. Transcription factors have a pivotal role in the development and differentiation of mast cells in response to various microenvironmental signals encountered in the resident tissues. Understanding the regulation of mast cells by transcription factors is therefore vital for mechanistic insights into allergic diseases. In this review we summarize advances in defining the transcription factors that impact the development of mast cells throughout the body and in specific tissues, and factors that are involved in responding to the extracellular milieu. We will further describe the complex networks of transcription factors that impact mast cell physiology and expansion during allergic inflammation and functions from degranulation to cytokine secretion. As our understanding of the heterogeneity of mast cells becomes more detailed, the contribution of specific transcription factors in mast cell-dependent functions will potentially offer new pathways for therapeutic targeting.

Microphthalmia (mi) in Murine Mast Cells: Regulation of Its Stimuli-Mediated Expression on the Translational Level

Mice harboring a mutation in the microphthalmia (mi ) gene display a variety of abnormalities, including microphthalmia, depletion of skin melanocytes, deafness, a defect in osteoclasts, and a major decrease in mast cell number and function. However, despite the possible critical role played by this protein in mast cell development and function, characterization of its mRNA and protein synthesis in these cells has not yet been performed. In this study, we investigated the regulation of the synthesis of mi in murine mast cells activated by various physiologic stimuli. Using a specific rabbit polyclonal anti-mi antibody, we found that interleukin-3, interleukin-4, or aggregation of the mast cell high-affinity receptor for IgE (FcεRI) induced the synthesis of mi protein in these cells. None of these stimuli significantly affected the level of mi mRNA in the mast cells at any of the time points tested. Also, using this specific anti-mi antibody, an increase in mi protein synthesis was shown during differentiation of mast cells from their bone marrow cell precursors. Moreover, a complex containing mi bound to upstream stimulating factor 2 was detected only in activated mast cells. We conclude that the regulation of mi expression is on the translational level. Thus, stimulation of mast cells by a variety of stimuli elicits a signaling pathway that regulates mi expression.