| Budget Amount *help |
¥13,600,000 (Direct Cost: ¥13,600,000)
Fiscal Year 2004: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 2003: ¥11,200,000 (Direct Cost: ¥11,200,000)
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| Research Abstract |
Chitinase family proteins are endogenous lectins which have affinity to N-acetylglucosamine. Two members with chitinase activity, acidic mammalian chitinase (AMCase) and chitotriosidase, have been identified in mammals, and their cellular expressions were investigated in the present study. Furthermore, we selected two chitinase family proteins without the chitinase activity, Ym and brp-39, and revealed their expression sites. AMCase was contained in secretory granules of parotid gland acinar cells and gastric chief cells, secreted in the saliva and gastric juice, respectively. Bovine AMCase, on the other hand, was produced in the liver and released into the blood. A sharp increase of blood AMCase concentration caused by Theileria infection suggested the role in defense against pathogenic bacterial and parasitic infection. Although human chitotriosidase is expressed in macrophages and neutrophils, the mouse counterpart was expressed in the stratified epithelium of oral cavity, suggesting another function of this chitinase. Ym1 was expressed in premature neutropluls in the bone marrow and spleen of mice, but disappeared in mature neutrophils. Macrohages in the bone marrow also contained Ym in association with intracellular needle-like crystals. In the lung, Ym was contained in alveolar macrophages and secreted into alveolar space. In mice infected with M. Corti, inflammatory cells expressing Ym gathered around the parasites residing in the liver, while Ym-containing macrophages in the lung increased in number and changed to multinudeated giant cells. Brp-39 was expressed by chondrocytes at the endochondral ossification of the joint, and by acinar cells in involuted mammary glands. Since mammary glands during lactation never expressed brp-39, this chitinase might be involved in the involution of mammary gland or tissue reconstruction.
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