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 自身反应性 T 细胞无法经历阴性的自我耐受 胸腺内成熟过程中的选择。我们发现植入 少量β细胞进入胸腺易患糖尿病的新生儿 BB 大鼠可防止胰岛预期的自身免疫破坏 原生胰腺。这为我们提供了一个理想的解剖模型 胰岛复合体来定义特定的自身抗原成分 胰岛是糖尿病的目标，因此也可能是 可用于免疫治疗。胰岛的细胞成分（内分泌细胞与 抗原呈递细胞）和亚细胞元件（谷氨酸 脱羧酶和胰岛素）将被评估为可能的糖尿病致病因素 自身抗原。 我们将用全胰岛、APC 接种新生 BB 大鼠的胸腺 游离胰岛、GAD 蛋白、胰岛素和表达的非胰岛细胞 GAD（神经元细胞）或胰岛素（垂体细胞） 设计用于生产胰岛素）。将监控接收者以确定 是否有任何这些治疗方法，例如胸腺内接种整个 胰岛，对糖尿病的发展具有保护作用。 我们在初步免疫组织化学研究中取得了令人惊讶的发现 表达 GAD 的移植神经元细胞的胸腺是 胸腺细胞本身也表达GAD。额外的观察结果是 BB 大鼠胸腺内 GAD 表达的解剖模式不同 正常老鼠的研究很有趣，可能具有病因学意义。 通过分子检测，我们将确认胸腺 GAD 的存在。我们将 研究其他正常人和糖尿病易感人群胸腺中的 GAD 表达 动物（例如 NOD 小鼠）以确定观察结果的普遍性。我们 还将研究GAD表达的胸腺模式是否可以 通过已知可预防 BB 大鼠糖尿病的操作使其正常化，例如叉 与正常大鼠交配，新生儿骨髓移植 正常捐赠者。 很难调和 GAD 作为 关键的糖尿病自身抗原及其存在（而不是预期的 缺乏）来自糖尿病易感大鼠的胸腺，除非胸腺内有缺陷 BB 大鼠体内出现这种自身抗原会阻碍其 负选择 β 细胞自身反应性 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中来探索 BB鼠。 由于我们可以通过新生 BB 大鼠的胸腺操作来预防糖尿病， 我们还将探索这些策略在患有急性疾病的动物中的应用 发病糖尿病以确定受到自身免疫攻击的胰岛是否可以 获救了。类似的方法也将用于老年动物 自从人类最终应用这些方法以来就确诊了糖尿病 可能不适用于新生儿。后面的研究将 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 肽破坏移植的胰岛 类似物。