Regulatory B-cells Limit CNS Inflammation and Infarct in Experimental Stroke

调节性 B 细胞限制实验性中风中的中枢神经系统炎症和梗死

• 批准号: 8186316
• 负责人: Halina Offner
• 金额: $ 38.12万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-15 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8186316
• 关键词: Animals; Anti-Inflammatory Agents; Anti-inflammatory; Apoptosis; Apoptotic; B-Lymphocyte Subsets; B-Lymphocytes; Blood; Brain; Brain Injuries; Brain Ischemia; CD19 gene; CD22 gene; Cause of Death; Cell Count; Cell Therapy; Cells; Cerebral Ischemia; Cerebral hemisphere; Clinical; Contralateral; Corpus striatum structure; Data; Disease; Employee Strikes; Event; Experimental Models; Frequencies; Human; Immune; Immune system; Infarction; Infection; Inflammation; Inflammatory; Interleukin-10; Ipsilateral; Ischemic Stroke; Ligands; Lymphocyte Depletion; Lymphoid Tissue; Mediating; Middle Cerebral Artery Occlusion; Modeling; Multiple Sclerosis; Mus; Organ; Outcome; Pathology; Pathway interactions; Patients; Peripheral; Receptor Activation; Rodent; Rodent Model; Role; Severity of illness; Spleen; Stroke; Systemic disease; Thymus Gland; Time; United States; Wild Type Mouse; acute stroke; base; central nervous system injury; cytokine; design; disability; functional outcomes; immune depression; improved; injured; nervous system disorder; neurotoxic; novel; receptor; reconstitution; restoration; theories

DESCRIPTION (provided by applicant): Recent studies have identified a small but powerful subset of IL-10-producing CD1dhiCD5+ regulatory B lymphocytes (B10) that can limit CNS inflammation and clinical signs of neurological disease in rodent models. In this multi-PI application, we hypothesize that endogenous regulatory B-cells, including the B10 subset, limit infarct size in MCAO by controlling immune-mediated inflammation triggered both in the CNS and in peripheral immune organs by focal stroke. Further, we predict that either selective induction or passive transfer of B10 cells so as to augment B10 cell frequency will provide additional regulatory effects in wild type (WT) mice, and result in smaller infarct and improved functional stroke outcome. The aims of this application are: 1) Determine the effects of B lymphocyte depletion and regulatory B10 cell restoration and treatment on infarct size, immune cellular composition and inflammatory signature in both spleen and brain hemispheres after MCAO. The hypothesis is that B cell KO mice sustain larger histological damage and poor functional outcome than do WT mice. We will determine the responsible B-cell subpopulations, including the IL-10-secreting B10 subset. 2) Evaluate the contribution of the PD-1/PD-L negative co-activation pathway to infarct size, immune cell composition and inflammatory signature in spleen and brain. The hypothesis is that activation of this receptor-ligand pathway in B lymphocytes, particularly CD1dhiCD5+ B-cells, alters outcomes from MCAO. This aim will evaluate PD-1, PD-L1 and PD-L2 expression on B-cells, confirm our preliminary findings of increased infarct size in PD-1 KO mice, extend the analysis to PD-L1 and PD-L2 KO mice, and evaluate the contribution of B10- cells to the PD-1/PD-L negative co-activation after stroke by reconstituting PD-L KO mice with WT B10-cells. 3) Evaluate the mechanisms through which B-cells inhibit microglial (MG) activation and release of neurotoxic factors. The hypothesis is that B cells, particularly CD1dhiCD5+ B regulatory cells, improve post-ischemic outcomes by suppressing microglial activation, either via secreted factors or direct cell-cell contact that enables a PD-1 negative co-activation mechanism. Specifically, this aim will evaluate interaction between PD-L+ CD19+ B-cells or IL-10-producing CD1dhiCD5+ B-reg cells and activated PD-1+ MG. The proposed studies offer high impact for the stroke field by virtue of their: 1) complete novelty, 2) focus on the inflamma-suppressive regulatory capacity of select B-cell subsets and 3) ability to lay translational groundwork for regulatory B-cell therapy in acute stroke. PUBLIC HEALTH RELEVANCE: Ischemic stroke is one of the leading causes of death and disability in the United States yet relatively little is known about the contribution to and effects on the immune system during stroke. We have focused on both early and late events in the peripheral immune system during stroke, have observed important changes in the spleen that occur simultaneously with the evolving brain injury, and are studying an important type of immune cells, B lymphocytes, which may have the ability to modulate both brain injury and spleen inflammation after a stroke event. If our initial findings are borne out, a class of B lymphocytes may offer protection to the injured brain.

描述（由申请人提供）：最近的研究发现，产生 IL-10 的 CD1dhiCD5+ 调节性 B 淋巴细胞 (B10) 的一个小而强大的子集可以限制啮齿动物模型中的中枢神经系统炎症和神经系统疾病的临床症状。在这个多 PI 应用中，我们假设内源性调节 B 细胞（包括 B10 子集）通过控制局灶性中风在中枢神经系统和外周免疫器官中触发的免疫介导炎症来限制 MCAO 中的梗塞范围。此外，我们预测选择性诱导或被动转移 B10 细胞以增加 B10 细胞频率将在野生型 (WT) 小鼠中提供额外的调节作用，并导致更小的梗塞和改善功能性中风结果。本应用的目的是：1) 确定 B 淋巴细胞耗竭以及调节性 B10 细胞恢复和治疗对 MCAO 后脾脏和大脑半球梗死面积、免疫细胞组成和炎症特征的影响。假设 B 细胞 KO 小鼠比 WT 小鼠遭受更大的组织学损伤和较差的功能结果。我们将确定负责的 B 细胞亚群，包括分泌 IL-10 的 B10 子集。 2) 评估 PD-1/PD-L 负共激活途径对脾脏和大脑中梗死面积、免疫细胞组成和炎症特征的影响。假设 B 淋巴细胞（尤其是 CD1dhiCD5+ B 细胞）中这种受体-配体途径的激活会改变 MCAO 的结果。该目的将评估 B 细胞上的 PD-1、PD-L1 和 PD-L2 表达，证实我们关于 PD-1 KO 小鼠梗塞面积增加的初步发现，将分析扩展到 PD-L1 和 PD-L2 KO 小鼠，并通过用 WT B10 细胞重建 PD-L KO 小鼠来评估 B10 细胞对中风后 PD-1/PD-L 负共激活的贡献。 3) 评估 B 细胞抑制小胶质细胞 (MG) 激活和神经毒性因子释放的机制。该假设认为，B 细胞，特别是 CD1dhiCD5+ B 调节细胞，通过抑制小胶质细胞激活来改善缺血后的结果，无论是通过分泌因子还是直接细胞与细胞接触，从而实现 PD-1 负共激活机制。具体而言，该目标将评估 PD-L+ CD19+ B 细胞或产生 IL-10 的 CD1dhiCD5+ B-reg 细胞与激活的 PD-1+ MG 之间的相互作用。拟议的研究对中风领域产生了重大影响，因为它们：1）完全新颖，2）专注于选定的 B 细胞亚群的炎症抑制调节能力，3）为急性中风的调节性 B 细胞治疗奠定转化基础的能力。 公共卫生相关性：缺血性中风是美国死亡和残疾的主要原因之一，但人们对中风期间免疫系统的贡献和影响知之甚少。我们重点关注中风期间外周免疫系统的早期和晚期事件，观察到与脑损伤同时发生的脾脏的重要变化，并正在研究一种重要的免疫细胞类型，即B淋巴细胞，它可能具有在中风事件后调节脑损伤和脾脏炎症的能力。如果我们的初步发现得到证实，一类 B 淋巴细胞可能会为受伤的大脑提供保护。