Immunological Mechanisms Underlying T1dm Pathogenesis

T1dm 发病机制的免疫学机制

• 批准号: 7734282
• 负责人: David Harlan
• 金额: $ 26.39万
• 依托单位: NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7734282
• 关键词: Adoptive Transfer; Antigen-Presenting Cells; Antigens; Autoantigens; Autoimmune Diabetes; Autoimmune Diseases; Autoimmune Process; Autoimmune Responses; Automobile Driving; Beta Cell; Blood Glucose; Blood Vessels; C-terminal; CD80 gene; CD8B1 gene; Catalytic Domain; Cell Line; Cell surface; Cells; Cessation of life; Characteristics; Chronic; Clinical; Cytotoxic T-Lymphocytes; Defect; Dendritic Cells; Development; Diabetes Mellitus; Diabetic mouse; Discipline; Disease; Dose; Epitopes; Exercise; Experimental Genetics; Fibroblasts; Gene Expression; Genes; Genetic Predisposition to Disease; Glycoproteins; Goals; HLA-A2 Antigen; Health; Homing; Hormonal; Human; Immune; Immune response; Immune system; Immunization; Inbred NOD Mice; Incidence; Individual; Inflammatory; Injection of therapeutic agent; Insulin; Insulin-Dependent Diabetes Mellitus; Integrins; Lead; Left; Life; Ligands; Link; Lymphocyte Function; Lymphoid; Mediating; Membrane; Memory; Modeling; Mus; Myotonic Dystrophy; Nerve; Non obese; Organ; Pancreas; Pathogenesis; Patients; Peptides; Peripheral; Phenotype; Phosphotransferases; Population; Process; Proliferating; Protein-Serine-Threonine Kinases; Proteins; Publishing; Rattus; Relative (related person); Reporting; Research; Signal Transduction; Structure of beta Cell of islet; Surface; System; T-Cell Activation; T-Lymphocyte; Testing; Thinking; Tissues; To autoantigen; Transgenes; Transgenic Mice; Transgenic Organisms; Viral; Virus; Work; autoreactive T cell; cell killing; chemokine; cytokine; diabetic; glucose monitor; glucose-6-phosphatase; insulin secretion; islet; killings; lymph nodes; man; migration; mouse model; prevent; promoter; protective effect; receptor; response; trait

Type 1 diabetes mellitus (T1DM) is an autoimmune disease resulting from the T cell mediated destruction of insulin-producing beta cells located in the pancreas. Current treatment, which includes insulin replacement by injection, frequent blood glucose monitoring, and dietary/exercise discipline, can prevent death from hormonal insufficiency, but is not curative and does not completely prevent the long-term complications including nerve damage, and vascular damage to both large and small blood vessels. In previous few years, we developed a transgenic mouse to express the T cell costimulatory receptor CD80 on its pancreatic insulin producing beta cells (under the control of the rat insulin promoter abbreviated RIP) and demonstrated the mouse's extraordinary sensitivity to autoantigen induced immune mediated beta cell destruction, and thus to diabetes. We refer to the diabetes induced in these RIP-CD80 mice as experimental autoimmune diabetes (EAD). Using this EAD model, we've found that relatively weak anti-beta cell autoimmune responses can cause chronic progressive and eventually complete beta cell destruction resulting in symptomatic and irreversible disease. The slow but inexorable process is highly reminiscent of the beta cell destruction leading to clinical T1DM in man, typically months to years of anti-beta cell immune activity precedes sufficient beta cell killing for the blood sugars to rise. Most other autoimmune diabetes studies involve the non-obese diabetic (NOD) mouse, which develops spontaneous diabetes, or virus-induced diabetes models. Only the RIP-CD80 transgenic mouse diabetes model is characterized by an experimental genetic susceptibility trait (in the EAD model the trait is the CD80-transgene) rendering the mouse susceptible to autoantigen-specific T lymphocyte sensitization as is thought to be present in T1DM patients. We have reported that immunizing with either experimentally-introduced autoantigen (e.g. pancreatic beta cell-expressed viral glycoprotein) or endogenous beta cell autoantigen (e.g. insulin) could lead to diabetes in RIP-CD80 mice. Further, most studies now support that the normal individual's T cell repertoire contains potentially autoreactive but quiescent T cells. We concluded that pancreatic beta cell likely contains many autoantigens and that effective control mechanisms must exist to prevent autoimmune responses in healthy individuals. Current immunological dogma suggests that naove CD8 cytotoxic T cell (CTL) precursors respond to strong antigen stimulation in a characteristic fashion by: (i) proliferating and releasing inflammatory cytokines, (ii) differentiating into CTLs and, (iii) down modulating certain surface interaction molecules to allow the CTLs to leave secondary lymphoid organs while increasing other receptors, such as integrins, to promote entry into peripheral tissues, and (iv) changing chemokine signals necessary to facilitate the relocation of activated CTL from lymph nodes (LN) to inflamed peripheral tissues. The EAD model has allowed us to study the response of beta cell-specific CD8 T cells to cognate antigen presented by either professional antigen-presenting cells (APC) like mature dendritic cells DC), or by non-professional (np) APCs like fibroblast-like cell lines (FCL). While DC-stimulated T cells produced the expected effector CTL phenotype described above, FCL-activated T cells were quite different. Relative to DC activated CTLs, the FCL-activated CTLs proliferated less, released equivalent proinflammatory cytokines, and surprisingly displayed increased cytolytic function. Moreover, FCL-stimulated T cells largely failed to switch their homing receptors predicting poor migration from the lymph nodes to the periphery. Most strikingly, however, FCL-stimulated but not DC-activated CTL expressed many of the features associated with memory CTLs; both multiple memory cell surface marker expressioon and predominant homing into secondary lymphoid organs upon adoptive transfer into naive mice. Importantly, while every CTL response gives rise to a small population of long-lived memory CTL, the mechanism that decides the fate of an individual CTL to become a memory cell remains largely unknown. Finally, the FCL-stimulated CTL induced diabetes by a slow, chronic process, suggesting that these central memory CTL might also be involved in driving human T1DM. Research goals pursued in FY 2008: 1. We developed a potent cell immunization strategy using mature dendritic cells loaded with antigenic peptides (derived from beta cell-made proteins), and established a clear antigen-dose diabetes-response relationship for two experimental autoantigen determinants (peptides), encoded by the transgenic LCMV-GP specifically expressed by beta cells. We hypothesize (and we are testing) that antigenic peptides representing genuine beta cell target epitopes will similarly mediate beta cell killing and diabetes development in this test system. 2. We have identified two beta-cell derived peptides (one from a serine/threonine kinase called dystrophia myotonica kinase (DMK) aa143-151, and the other from the islet-specific glucose-6-phosphatase catalytic subunit-related gene (IGRP) aa225-233) capable of sensitizing immune cells to destroy beta cells. These antigenic peptides have previously been reported to be able to mediate diabetes in another mouse diabetes model, the non-obese diabetic (NOD) mouse. Other H2b-restricted antigenic peptides, several published as autoantigenic peptide candidates, did not activate a genuine anti-beta cell response in our test system. 3. We tested comparable approaches in mice "humanized" to express a chimeric human HLA-A2 linked to the murine H2K(b) C-terminal sequences. This membrane molecule has been shown to function as a MHC classs I molecule in mice yet present human (HLA-A2-restricted) epitopes to mouse T cells. Autoantigenic peptides identified using these mice could be used to test autoreactive T cells in HLA-A2 positive subjects with T1DM (about 50 percent of the population). We found a surprising protective effect conferred by the HLA-A2 gene expression. 4. Immune cells in draining lymph nodes are continuously exposed to autoantigen from peripheral organ cells. We have observed that beta cell specific T cell activation depends on the cognate antigen but also on the context of T cell activation. Sub-optimally activated T cells (using either altered peptide ligands (APL) or non-professional (immature) APC) display both bridled effector lymphocyte functions (killing, cytokine secretion) and migration. These defects resulted in markedly reduced diabetes incidence in our EAD model. Current efforts are focused on strategies to induce migration-defective T cells that would be maintained in the draining lymph nodes by presence of autoantigen and there work to down-modulate the anti-beta cell immune response.

1型糖尿病（T1DM）是一种自身免疫性疾病，由T细胞介导的胰腺中产生胰岛素的β细胞的破坏引起。目前的治疗包括注射胰岛素替代、频繁血糖监测和饮食/运动纪律，可以防止因激素不足而死亡，但不能治愈，也不能完全预防长期并发症，包括神经损伤和大血管和小血管损伤。

项目成果

Cytotoxic T cell-mediated diabetes in RIP-CD80 transgenic mice: autoantigen peptide sensitivity and fine specificity.

RIP-CD80 转基因小鼠中细胞毒性 T 细胞介导的糖尿病：自身抗原肽敏感性和精细特异性。

• DOI: 10.1196/annals.1394.008
• 发表时间: 2007
• 期刊: Annals of the New York Academy of Sciences
• 影响因子: 5.2
• 作者: Pechhold,Klaus;Chakrabarty,Sagarika;Harlan,DavidM
• 通讯作者: Harlan,DavidM

Rescue of hematopoietic stem cells following high-dose radiation injury using ex vivo culture on endothelial monolayers.

使用内皮单层离体培养来拯救高剂量辐射损伤后的造血干细胞。

• 发表时间: 2002
• 期刊: Military medicine
• 影响因子: 1.2
• 作者: Chute,JohnP;Clark,William;Saini,Abha;Wells,Mark;Harlan,David
• 通讯作者: Harlan,David

Beta cell-specific CD80 (B7-1) expression disrupts tissue protection from autoantigen-specific CTL-mediated diabetes.

Beta 细胞特异性 CD80 (B7-1) 表达会破坏组织对自身抗原特异性 CTL 介导的糖尿病的保护。

• DOI: 10.1016/s0896-8411(02)00105-1
• 发表时间: 2003
• 期刊: Journal of autoimmunity
• 影响因子: 12.8
• 作者: Pechhold,Klaus;Karges,Wolfram;Blum,Carmen;Boehm,BernhardO;Harlan,DavidM
• 通讯作者: Harlan,DavidM

Islet neogenesis associated protein transgenic mice are resistant to hyperglycemia induced by streptozotocin.

胰岛新生相关蛋白转基因小鼠对链脲佐菌素诱导的高血糖有抵抗力。

• DOI: 10.1677/joe.1.06698
• 发表时间: 2006
• 期刊: The Journal of endocrinology
• 作者: Taylor-Fishwick,DavidA;Bowman,Angela;Hamblet,Natasha;Bernard,Paul;Harlan,DavidM;Vinik,AaronI
• 通讯作者: Vinik,AaronI