MECHANISM OF OSTEOPOROSIS IN IL-4 TRANSGENIC MICE

IL-4转基因小鼠骨质疏松机制

• 批准号: 3162092
• 负责人: DAVID BRAM LEWIS
• 金额: $ 16.44万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-07-10 至 1996-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3162092
• 关键词: bone metabolism; cytokine; disease /disorder model; genetic promoter element; genetically modified animals; interleukin 4; laboratory mouse; osteoporosis; physiologic bone resorption; tissue /cell culture

Osteoporosis is a significant and growing cause of morbidity and mortality in the United States. Cytokines produced in bone tissue can impact on bone resorption and formation, and may also play a role in the pathogenesis of osteoporosis. Defining the pathophysiologic mechanisms which cause osteoporosis, including cytokine-mediated mechanisms, has been hampered by the lack of convenient animal models. This proposal seeks to define the mechanisms which lead mice bearing in lck-IL-4 transgene to invariably develop severe osteoporosis. In the lck-IL-4 transgene, the transcription of the cytokine, interleukin-4 (IL-4), is directed by the proximal promoter of the lymphoid-specific protein tyrosine kinase gene, lck. This results in increased expression of IL-4 by T-lineage cells of the thymus, and, to a lesser extent, by peripheral and bone marrow lymphoid cells. It is hypothesized that the development of osteoporosis in lck-IL-4 mice requires transgene expression, particularly within bone tissue. This will be tested by generating additional lines of lck-IL-4 mice and by determining if: a) anti-IL-4 antibody treatment ameliorates osteoporosis; b) transgene expression by bone marrow T cells positively correlates with disease severity; c) osteoporosis requires, and can be adoptively transferred by, lck-IL-4 peripheral T cells; d) osteoporosis in lck-IL-4 mice is cured by transplantation with wild-type bone marrow. If none of these predictions are correct, it will be assumed that transgene integration has disrupted or altered an endogenous gene, which may be critical for bone homeostasis; this gene will be cloned and characterized. Alternatively, if any of these predictions are correct, additional transgenic mice will be generated in which increased IL-4 production is selectively limited to osteoblasts. This will directly test whether locally-increased IL-4 production in bone tissue is sufficient to induce osteoporosis. In parallel with the above studies, osteoblast and osteoclast function in bone will be assessed in situ by enzymo- and immuno-histochemical assays as well as by histomorphometry. Serum will be assayed to exclude metabolic and/or endocrinologic disorders as the cause of osteoporosis. These studies should provide new insights in to the pathogenesis of osteoporosis, and the role that IL-4 may play in this disease. They may also point out potential pitfalls of systemic immunotherapy with cytokines such as IL-4.

骨质疏松症是一个重要的和日益增长的发病原因， 死亡率在美国。骨组织中产生的细胞因子可以 影响骨吸收和形成，也可能在 骨质疏松症的发病机制。定义病理生理机制 导致骨质疏松症，包括甜菜碱介导的机制， 由于缺乏方便的动物模型，这项建议 试图确定导致小鼠携带lck-IL-4的机制， 转基因不可避免地发展成严重的骨质疏松症。在lck-IL-4中， 转基因，转录的细胞因子，白细胞介素-4（IL-4）， 由淋巴特异性蛋白的近端启动子指导 酪氨酸激酶基因，lck。这导致IL-4的表达增加 胸腺的T系细胞，以及在较小程度上， 和骨髓淋巴样细胞。据推测， lck-IL-4小鼠中骨质疏松症的发生需要转基因表达， 特别是在骨组织内。这将通过生成 另外的lck-IL-4小鼠系，并通过确定是否：a）抗IL-4 抗体治疗改善骨质疏松症; B）通过 骨髓T细胞与疾病严重程度正相关; c） 骨质疏松症需要lck-IL-4，并且可以通过lck-IL-4过继转移 d）lck-IL-4小鼠中的骨质疏松症通过以下方法治愈： 野生型骨髓移植。如果这些预测 如果是正确的，则将假定转基因整合已被破坏， 或者改变了一个内源性基因，这可能对骨骼至关重要， 内稳态;该基因将被克隆和表征。可选择地， 如果这些预测中的任何一个是正确的， 其中增加的IL-4产生被选择性地限制 成骨细胞。这将直接测试局部增加的IL-4 在骨组织中的产生足以诱发骨质疏松症。在 与上述研究平行，成骨细胞和破骨细胞在 骨将通过酶和免疫组织化学测定进行原位评估 以及通过组织形态计量学。将对血清进行分析，以排除 代谢和/或内分泌紊乱是骨质疏松症的原因。 这些研究将为进一步了解肿瘤的发病机制提供新的思路。 骨质疏松症，以及IL-4可能在这种疾病中发挥的作用。他们可能 还指出了全身免疫治疗的潜在陷阱， 细胞因子如IL-4。