Solving the elusive mechanism of rapamycin action in lymphocytes

解决雷帕霉素在淋巴细胞中作用的难以捉摸的机制

基本信息

批准号：
8531852
负责人：
DAVID Alexander FRUMAN
金额：
$ 21.72万
依托单位：
UNIVERSITY OF CALIFORNIA-IRVINE
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-08-20 至 2014-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8531852
关键词：
Activated Lymphocyte Affect Antigens B-Lymphocytes Binding Proteins CCI-779 Calcineurin Cell Cycle Progression Cell Nucleus Cells Clinical Complex Cyclosporine Cytokine Gene Data Enzymes Event Exploratory/Developmental Grant FDA approved FK506 Family Funding Genes Genetic Genetically Engineered Mouse Goals Growth Factor Immune Immune Cell Activation Immune system Immunology Immunosuppression Immunosuppressive Agents Learning Lymphocyte Lymphocyte Activation Mammalian Cell Mammals Metabolism Mitogens Modeling Molecular Target Mouse Strains Names Nutrient Organ Organ Transplantation Output Pharmaceutical Preparations Phosphorylation Phosphotransferases Prevention Process Protein-Serine-Threonine Kinases Proteins Proto-Oncogene Proteins c-akt Reagent Regulation Reporting Residual state Resources Rewards Ribosomal Protein S6 Kinase Risk Role S Phase Signal Transduction Sirolimus Skeletal Muscle Specificity Stress System T-Cell Proliferation T-Lymphocyte Testing Textbooks Tissues Work base cancer cell cell type chemical genetics expectation human FRAP1 protein inhibitor/antagonist kinase inhibitor leukemia lymphocyte proliferation mouse model novel prevent protein function response ribosomal protein S6 kinase, 70kD, polypeptide 2

项目摘要

DESCRIPTION (provided by applicant): mTOR is a serine/threonine kinase that is expressed ubiquitously. The mTOR enzyme is present in two cellular complexes, TORC1 and TORC2. mTOR was discovered and named based on its interaction with the drug rapamycin. This compound is an allosteric inhibitor that partially blocks TORC1 activity and generally does not inhibit TORC2 function. Rapamycin treatment of T and B lymphocytes profoundly blocks proliferation triggered by antigen and other mitogens, and rapamycin (sirolimus; Rapamune(R)) is an FDA-approved immunosuppressant. However, rapamycin and analogs have lesser effects on proliferation in other cellular systems including cancer cells. Although the effects of rapamycin on lymphocytes have been studied for 20 years, it remains unclear why the compound induces a profound block of proliferation selectively in lymphocytes. Paradoxically, a novel class of ATP-competitive mTOR kinase inhibitors (TOR-KIs) causes less immunosuppression than rapamycin despite causing more complete inhibition of both TORC1 and TORC2. The goal of this project is to define mechanisms by which rapamycin selectively blocks proliferation of normal lymphocytes. Based on preliminary data, we propose two hypotheses that form the basis of separate specific aims. Aim 1 will test the hypothesis that rapamycin causes more complete and sustained inhibition of S6 kinases, key substrates of TORC1. There are two S6 kinases, S6K1 and S6K2, but their roles in lymphocyte activation and proliferation have not been reported. We will use a novel mouse model that will allow a chemical genetic approach to specifically inhibit S6K activity in normal T and B cells. We will use this model to compare the effects of S6K inhibition with the effects of rapamycin and TOR-KIs. Aim 2 will test the hypothesis that rapamycin inhibits kinase-independent functions of mTOR. We will generate a novel mouse strain in which kinase-dead mTOR can be expressed in a cell-specific manner. This will allow us to test the prediction that lymphocytes expressing kinase-dead mTOR will retain residual proliferation that remains sensitive to rapamycin. We will also begin a candidate approach to test possible kinase-independent mTOR functions.

描述（由申请人提供）：MTOR是一种丝氨酸/苏氨酸激酶，普遍表达。 MTOR酶存在于两个细胞复合物TORC1和TORC2中。 MTOR是根据与药物雷帕霉素的相互作用发现和命名的。该化合物是一种变构抑制剂，该抑制剂部分阻断了TORC1活性，并且通常不会抑制TORC2功能。 T和B淋巴细胞的雷帕霉素治疗深刻阻止抗原和其他有差异剂引发的增殖，而雷帕霉素（Sirolimus; rapamune（r））是FDA批准的免疫抑制剂。但是，雷帕霉素和类似物对包括癌细胞在内的其他细胞系统的增殖有较小的影响。尽管已经研究了雷帕霉素对淋巴细胞的影响已有20年了，但尚不清楚为什么该化合物在淋巴细胞中选择性地诱导了深层的增殖。矛盾的是，尽管对TORC1和TORC2的抑制更加完全抑制，但与雷帕霉素相比，一类新型的ATP竞争激酶抑制剂（TOR-KIS）会导致免疫抑制较少。该项目的目的是定义雷帕霉素有选择地阻断正常淋巴细胞的增殖的机制。根据初步数据，我们提出了两个假设，这些假设构成了单独的特定目标的基础。 AIM 1将检验雷帕霉素对S6激酶，Torc1的关键底物的更完整和持续抑制的假设。有两个S6激酶，S6K1和S6K2，但尚未报道它们在淋巴细胞激活和增殖中的作用。我们将使用一种新型的小鼠模型，该模型将允许一种化学遗传方法特异性抑制正常T和B细胞中的S6K活性。我们将使用此模型将S6K抑制作用与雷帕霉素和Tor-Kis的作用进行比较。 AIM 2将检验雷帕霉素抑制MTOR的激酶非依赖性功能的假设。我们将产生一种新型的小鼠菌株，其中激酶已超过MTOR可以以细胞特异性方式表达。这将使我们能够测试表达激酶死的淋巴细胞将保留对雷帕霉素敏感的残留增殖。我们还将开始一种候选方法，以测试可能与激酶无关的MTOR函数。