Optogenetic and Chemogenetic Dissection of Cell Transplants

帕金森病（PD）导致约100万美国人残疾，其特征是： 起源于黑质腹侧部（SNpc）的多巴胺能神经元的进行性损失及其 轴突在绝大多数患者中，需要某种形式的左旋多巴（LD）来控制PD症状，但其 使用会导致药物引起的运动障碍（DID）、运动和非运动波动、致残并发症， 仍然是当代PD管理中的一个主要问题。间歇性高剂量LD治疗， 持续多巴胺能刺激（CDS）与多巴胺受体超敏性一起被假设为 作为DID和波动的原因因素。也普遍认为，来自运动的信息传递 基底神经节和背部的皮质在PD和电生理异常的纠正中异常 可能对缓解晚期PD患者的症状至关重要。我们的研究表明， 帕金森综合征引起的基底神经节电生理变化 尽管帕金森病行为得到了很好的改善，但全天候LD治疗并未减轻。在 相反，多巴胺能细胞移植到纹状体中使基底神经节神经生理学“正常化”， 帕金森氏症的行为异常我们发现移植物和宿主之间的突触连接是 关键和必要的调解这些影响。这些发现表明，突触前因素，如 黑质纹状体突触的存在，使多巴胺的集中释放，其再摄取和调节，通过 突触前受体可能对最小化PD的运动并发症都很重要。最近的研究 表明多巴胺能细胞移植治疗帕金森病是成功的，没有有害的副作用， 为患者提供超过20年的有效抗帕金森病益处。这导致了解除 暂停临床细胞移植治疗PD。然而，细胞移植技术的优化 包括从外部控制移植物功能及其新形成的突触连接的能力 对于确保这种移植物未来临床转化的安全性至关重要。因此，我们寻求 全面评估基底神经节电生理“正常化”的假设- 皮层回路是必要的，以减轻或消除DID和PD的波动。用一只繁殖能力很强的老鼠 表现出DID和波动的PD模型，移植物的光遗传学和化学遗传学调节， 它们可以被“关闭”和“打开”，清醒基底神经节单细胞记录，LFP记录，EEG和体内 微透析结合HPLC-MS/MS，我们计划研究的生化和电异常， 基底神经节和皮质与DID和PD波动相关。基底神经节多核 并且其已知连接将被探测。还将进行广泛的组织学研究。本研究 将为伴随DID的电生理异常提供机制基础，运动和非运动 运动波动的PD和帮助发现的方法来纠正他们。

Parkinson's disease (PD) causes disability in an estimated 1 million Americans and is characterized by progressive loss of dopaminergic neurons that originate in the substantia nigra pars compacta (SNpc) and their axons. Levodopa (LD) in some form is required to control symptoms of PD in vast majority of patients, but its use causes drug-induced dyskinesias (DID), motor and non motor fluctuations, disabling complications that remains a major problem in contemporary management of PD. Intermittent high dose LD treatments, loss of continuous dopaminergic stimulation (CDS) along with dopamine receptor super sensitivity are hypothesized as causative factors for DID and fluctuations. It is also well accepted that information transfer from the motor cortex to the basal ganglia and back is abnormal in PD and correction of electrophysiological abnormalities may be critical to provide symptomatic relief to patients with advanced PD. Our studies show that the electrophysiological changes that occur in the basal ganglia as result of parkinsonism remain largely unmitigated with round the clock LD treatments despite excellent amelioration of parkinsonian behavior. In contrast, dopaminergic cell transplants into the striatum “normalize” basal ganglia neurophysiology and parkinsonian behavioral abnormalities. We show that synaptic connectivity between the graft and the host is critical and necessary to mediate these effects. These findings suggest that pre-synaptic factors such as the presence of nigrostriatal synapses that enables focused release of dopamine, its reuptake and regulation via pre-synaptic receptors may all be important to minimize the motor complications of PD. Recent studies have shown that dopaminergic cell transplantation for PD can be successful and without deleterious side effects providing >2 decades of effective anti-parkinsonian benefits to patients. This has led to the lifting of the moratorium on clinical cell transplantation for PD. However, optimization of cell transplantation techniques including the ability to externally control the functioning of the grafts and its newly formed synaptic connections with the host is critical to ensure safety of future clinical translation of such grafts. Therefore, we seek to comprehensively evaluate the hypothesis that electrophysiological “normalization” in the basal ganglia – cortical circuit is necessary to mitigate or eliminate DID and fluctuations in PD. Using a highly reproducible rat model of PD that exhibit DID and fluctuations, optogenetic and chemogenetic modulation of grafts such that they can be turned “off” and “on”, awake basal ganglia single cell recordings, LFP recordings, EEG and in vivo microdialysis combined with HPLC-Ms/Ms we plan to study the biochemical and electrical abnormalities in the basal ganglia and the cortex associated with DID and fluctuations in PD. Multiple nuclei in the basal ganglia and its known connections will be probed. Extensive histological studies will also be performed. This research will provide mechanistic basis for the electrophysiological abnormalities that accompany DID, motor and non- motor fluctuations in PD and help discover methods to correct them.