SPONTANEOUS DIABETES--PATHOGENESIS AND TREATMENT

自发性糖尿病——发病机制和治疗

• 批准号: 2137817
• 负责人: CLYDE F BARKER
• 金额: $ 33.94万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1979
• 资助国家: 美国
• 起止时间: 1979-06-01 至 1999-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2137817
• 关键词: NOD mouse; antigen presentation; antigen presenting cell; autoantigens; autoimmunity; biological signal transduction; bone marrow transplantation; diabetes mellitus therapy; gel electrophoresis; gene expression; glutamate decarboxylase; helper T lymphocyte; hyperglycemia; immunocytochemistry; immunotherapy; insulin; insulin dependent diabetes mellitus; laboratory rat; messenger RNA; organ culture; pancreatic islet transplantation; peptide analog; polymerase chain reaction; thymus; transplant rejection

Destruction of beta cells in diabetes is thought to be caused by a failure of self-tolerance whereby autoreactive T cells fail to undergo negative selection during intrathymic maturation. We have found that implantation of a small number of beta cells into the thymus of neonatal diabetes-prone BB rats prevents the expected autoimmune destruction of islets in the native pancreas. This provides us with an ideal model for dissection of the islet complex to define the specific autoantigenic component(s) of islets which are the targets of diabetes and which therefore could also be useful in immunotherapy. Cellular components of islets (endocrine cells vs antigen presenting cells) and subcellular elements (glutamic acid decarboxylase and insulin) will be evaluated as the likely diabetogenic autoantigens. We will inoculate the thymus of neonatal BB rats with whole islets, APC free islets, GAD protein, insulin, and non-islet cells which express either GAD (neuronal cells) or insulin (pituitary cells genetically engineered to produce insulin). Recipients will be monitored to determine whether any of these treatments, like intrathymic inoculation of whole islets, has a protective influence on the development of diabetes. A surprising finding made in our preliminary immunohistochemical search of the thymus for transplanted neuronal cells which express GAD was that thymic cells themselves also express GAD. The additional observation that the anatomical pattern of intrathymic expression of GAD differs in BB rats and normal rats is intriguing and could have etiological implications. With molecular assays we will confirm the presence of thymic GAD. We will study GAD expression in the thymus of other normal and diabetes-prone animals (e.g. NOD mice) to determine the generality of the observation. We will also study whether the thymic pattern of GAD expression can be normalized by maneuvers known to prevent diabetes in BB rats, e.g. cross breeding with normal rats, neonatal transplantation of bone marrow from normal donors. t is somewhat difficult to reconcile the crucial importance of GAD as the key diabetogenic autoantigen with its presence (rather than expected absence) from the thymus of diabetes prone rats, unless faulty intrathymic presentation of this autoantigen in BB rats prevents their ability to negatively select beta cell autoreactive T cells. This possibility will be explored by inoculating normal antigen-presenting cells into the thymus of BB rats. Since we can prevent diabetes by thymic manipulation of neonatal BB rats, we will also explore the use of these strategies in animals with acute onset diabetes to determine whether islets under autoimmune attack can be rescued. Similar methods will also be employed in older animals with established diabetes since eventual human application of these methods could probably not be employed in newborns. The latter studies will include novel methods of preventing allogeneic rejection and/or autoimmune destruction of transplanted islets with the use of a cyclic CD4 peptide analogue.

糖尿病中β细胞的破坏被认为是由失败引起的 自动反应性T细胞的自我耐受性未能发生负面 胸内成熟期间的选择。我们发现植入 少数β细胞进入新生儿糖尿病的胸腺 BB大鼠防止了预期的自身免疫性破坏胰岛 本地胰腺。这为我们提供了解剖的理想模型 胰岛复合物来定义特定的自身抗原分量 是糖尿病目标的胰岛，因此也可能是 可用于免疫疗法。胰岛的细胞成分（内分泌细胞与 抗原呈递细胞）和亚细胞元素（谷氨酸 脱羧酶和胰岛素）将被评估为可能的糖尿病 自动抗原。 我们将用全胰岛接种新生儿BB大鼠的胸腺APC 自由胰岛，GAD蛋白，胰岛素和非异质细胞表达 GAD（神经元细胞）或胰岛素（垂体细胞在遗传上 设计为产生胰岛素）。将监视接收者以确定 这些治疗中的任何一种，例如整体的静脉内接种 胰岛，对糖尿病的发展有保护性影响。 我们初步的免疫组织化学搜索中的一个令人惊讶的发现 表达GAD的移植神经元细胞的胸腺是 胸细胞本身也表达GAD。其他观察结果 GAD的胸膜表达的解剖模式在BB大鼠中有所不同 正常大鼠很有趣，可能具有病因。 通过分子测定，我们将确认存在胸腺GAD。我们将 研究其他正常和糖尿病的胸腺中的GAD表达 动物（例如点头小鼠）确定观察的通用性。我们 还将研究GAD表达的胸腺模式是否可以 通过已知可以预防BB大鼠糖尿病的演习进行标准化，例如叉 与正常大鼠育种，骨髓的新生儿移植 普通捐助者。 t调和GAD的关键重要性有些困难 关键的糖尿病性自动抗原具有其存在（而不是预期 除非有缺陷的胸膜，否则不存在糖尿病胸腺的胸腺 BB大鼠中这种自动抗原的介绍可阻止其能力 负选择β细胞自动反应性T细胞。这种可能性将是 通过将正常抗原呈递细胞接种到胸腺的胸腺 BB老鼠。 由于我们可以通过对新生儿BB大鼠的胸腺操纵来预防糖尿病，所以 我们还将探索这些策略在急性的动物中的使用 发作糖尿病以确定在自动免疫攻击下是否可以是 救出。类似的方法也将在年龄较大的动物中使用 建立的糖尿病以来这些方法最终应用的糖尿病 可能无法雇用新生儿。后一个研究将 包括预防同种异体排斥和/或自身免疫的新方法 使用环状CD4肽的移植胰岛破坏 类似物。