Diversity Supplement: B Cells Directly Alter Adaptive Plasticity to Support Functional Recovery After Stroke

我们的新数据来自过去的新调查者R01获奖期，显示中风后B细胞转化为 支持短暂性大脑中脑损伤后运动和认知恢复的偏远区域(例如齿状回) 动脉闭塞(TMCAo)。B细胞通过分泌白介素10提供神经营养支持 和额外的神经营养因子(S)，以支持中风后的可塑性。此次R01更新的中心假设是 B细胞亚群进入远离梗死区的大脑区域，提供长期的神经营养 支持功能恢复。脑源性神经营养因子介导突触传递和 健康期间的记忆形成和保护神经元免受谷氨酸诱导的中风后的兴奋性毒性。脑源性神经营养因子 也介导B细胞从骨髓中流出，并可由B细胞对谷氨酸的反应而产生 通过NMDAR亚单位GluN2A刺激。根据我们的试验数据，我们将测试：如果中风后的子集 B细胞，称为B细胞BDNF+，在遇到谷氨酸后上调BDNF；如果B细胞BDNF+支持运动 和认知恢复；如果老年女性的B细胞来源的BDNF受损。我们将使用4个月。(“年青”) 和16个月。(老年)雌性和雄性小鼠测试B细胞BDNF+是否支持神经元功能，可塑性，运动， 卒中后多领域认知康复。Aim 1将测试(1A)tMCAO后，谷氨酸是否与B细胞结合 GluN2A增加BDNF的产生并驱动与恢复相关的细胞内钙信号，即性和 依年龄而定。我们将(1B)在体外使用B细胞Ntrk2tm1Ddg/J来测试BDNF受体TrkB是否需要 脑源性神经营养因子的产生和体外神经保护。AIM 2将测试B细胞BDNF+是否支持远程可塑性、运动和 初级运动皮质光血栓卒中模型的认知恢复。(2A)所有B的可诱导耗尽 年轻和老年雌性hCD20TamCre/BDNFfl/fl小鼠和产仔鼠的细胞或(2B)特异性B细胞来源的BDNF 控制将发生急性(D0)或延迟(卒中后D7开始)。主要结果将包括1) 梗塞周围和对侧M1的可塑性，2)提高前肢的精确度，3)保存 巴甫洛夫式刺激--自动触摸屏任务中的强化学习。AIM 3将测试B细胞来源的BDNF 增强长期的运动和认知恢复。老龄C57BL/6J雌性小鼠将接受tMCAo或Sham 手术和过继转移(3A)过表达BDNF或(3B)缺乏BDNF的B细胞，后者源于 HCD20TamCre/BDNFfl/fl供体小鼠，卒中后7天开始。主要成果将包括1)改善 通过触摸屏模式测试精确熟练的触觉，2)改善海马区特有的认知障碍 分离，以及3)通过全脑序列确定的B细胞的局部自发性和对应性渗出 双光子断层扫描，它与动物体内大脑回路特异性认知功能的大小相关 和运动恢复。这些研究将证实一种新的B细胞亚群B细胞的年龄相关性丢失 细胞BDNF+，在雌性。他们还将证实，以B细胞为靶点的治疗可以改善运动和 认知缺陷−是一种潜在的治疗方法，支持中枢神经系统损伤或疾病后基于可塑性的恢复。

Our novel data from the past New Investigator R01 award period show post-stroke B cells diapedese into remote regions (e.g. dentate gyrus) that support motor and cognitive recovery after transient middle cerebral artery occlusion (tMCAo). B cells can provide neurotrophic support through secretion of both interleukin (IL)-10 and additional neurotrophin(s) to support post-stroke plasticity. The central hypothesis of this R01 renewal is that a subset of B cells diapedese into brain regions remote from the infarct to provide long-term neurotrophic support for functional recovery. Brain-derived neurotrophic factor (BDNF) mediates synaptic transmission and memory formation during health and protects neurons from glutamate-induced excitotoxicity after stroke. BDNF also mediates B cell egress from bone marrow and can be produced by B cells in response to glutamate stimulation through the NMDAR subunit GluN2A. Based on our pilot data, we will test: if a subset of post-stroke B cells, referred to as B cellsBDNF+, upregulate BDNF after encountering glutamate; if B cellsBDNF+ support motor and cognitive recovery; and if B cell-derived BDNF is impaired in aged females. We will use 4 mos. (“young”) and 16 mos. (“aged”) female and male mice to test if B cellsBDNF+ support neuronal function, plasticity, motor, and multi-domain cognitive recovery post-stroke. Aim 1 will test if (1A) post-tMCAo, glutamate binds to B cell GluN2A to increase BDNF production and drive recovery-linked intracellular Ca2+ signaling that is sex- and age-dependent. We will (1B) use B cellsNtrk2tm1Ddg/J in vitro to test if the BDNF receptor TrkB is required for BDNF production and in vitro neuroprotection. Aim 2 will test if B cellsBDNF+ support remote plasticity, motor and cognitive recovery in a primary motor cortex photothrombosis stroke model. Inducible depletion of (2A) all B cells or (2B) specific B cell-derived BDNF in young and aged female hCD20TamCre/ BDNFfl/fl mice and littermate controls will occur either acute (at D0) or delayed (beginning D7 post-stroke). Primary outcomes will include 1) peri-infarct and contralesional M1 plasticity, 2) improved forelimb precision reaching, and 3) preservation of Pavlovian stimulus-reinforcer learning on an automated touchscreen task. Aim 3 will test if B cell-derived BDNF augments long-term motor and cognitive recovery. Aged C57BL/6J female mice will receive tMCAo or sham surgery and adoptive transfer of B cells that (3A) overexpress BDNF or (3B) lack BDNF, the latter derived from hCD20TamCre/BDNFfl/fl donor mice, beginning D7 post-stroke. Primary outcomes will include 1) improved precision skilled reaching, 2) ameliorated hippocampal-specific cognitive deficits tested via touchscreen pattern separation, and 3) regional ipsi- and contralesional diapedesis of B cells, as determined via whole brain serial two-photon tomography, that correlates to within-animal magnitude of brain circuit-specific cognitive function and motor recovery. These studies will confirm an age-dependent loss of a novel subset of B cells, B cellsBDNF+, in females. They will also confirm that therapeutically targeting B cells can improve motor and cognitive deficits − a potential treatment supporting plasticity-based recovery after any CNS injury or disease.