Mast cells are central effector that cause immediate hypersensitive responses to onset of allergy syndromes through the IgE mediated release of a variety of chemical materials.
Histamine is synthesized in mast cells and basophils by the action of histidine decarboxylase (HDC) on L-histidine, the major chemical mediator that implicated in mechanism of allergic reactions, such as vasodilation, branchial smooth muscle contraction and mucus secretion. Thus, HDC activity level in mast cells has a possibility to play a crucial role in histamine signaling and capable of production of histamine. Moreover, allergic desease are condidered as imbalance in Thl and Th2 cytokines, especially in IL-4 versusu IL-13, which can drive the differentiation of naive T helper cells into Th2 cells and facilitate allergic reactions. Therefore, search for effective components that modukate histamine release and Th2 cytokine production from mast cells are indicated for immuno therapeutic approaches to allergy disease.
Recently, several nudicated factors are known as key regulators of immune cell functions, which control the development of allergic reaction. To elucidate the role of essential amino acids and retinoic acids in mast cells, the effects of histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, all-trans retinoic acid and 9-cis retinoic acid on cell proliferation and expression of allergy-related genes in the rat basophil leukemia cell line, which is a model system for the analysis of IgE recepor-mediated histamine release, were studied.
Reverse transcription polymerase chain reaction analysis revealed that HDC mRNA expression was increased in the presence of histidine, caline and all-trans retinoic acid. OL-4 mRNA expression was also increased in the presence of several essential amino acids. In contrast. mRNA expression of IL-13, high-affinity IgE receptor and inflammatory cytokine TNFa were significantly suppressed by the almost of amino acid and retinoic asid.
From these results, the expression of allergy related genes is influenced by essential amino acids and retinoic acid. Histidine, in particular, was up-regulated activation on mast cells.