Therapeutic targeting of aberrant glial function during Juvenile Batten Disease

描述(申请人提供)：青少年神经性干酪样脂褐质沉着症(JNCL)是一种由CLN3基因的常染色体隐性突变引起的溶酶体储存性疾病。JNCL的发病年龄在5-10岁之间，表现为进行性视力丧失、癫痫发作、认知和运动能力下降，并在十几岁至二十出头时死亡。JNCL没有治疗方法，这突显了寻找新的治疗方法对改善患有这种致命疾病的儿童的寿命和生活质量的重要性。我们实验室最近的工作表明，JNCL早期异常的神经胶质激活可能是神经元丢失的原因之一。特别是，CLN3？EX7/8小胶质细胞被激活以产生许多具有已知神经毒性作用的促炎介质，而野生型(WT)细胞则无反应。在CLN3？EX7/8小鼠的许多脑区，星形胶质细胞半通道(HC)的开放也被增强，这允许分子从细胞内环境到细胞外环境的非歧视通过和生理梯度的破坏。JNCL早期的HC开放和异常的小胶质细胞激活相结合，可能扰乱了大脑代谢组，导致最终导致神经元丢失的病理性事件链。我们的假设是，用两类影响多条通路的化合物靶向异常的神经胶质细胞激活将显著延缓JNCL的进展。第一种是INI-0602，是一种新型的HC抑制剂，可以将CLN3？EX7/8小鼠中谷氨酸的积累减少到WT动物的典型水平。另一组包括第二代磷酸二酯酶4(PDE4)抑制剂，罗氟司特和PDE4亚型特异性抑制剂，由辉瑞公司提供，可减弱CLN3、EX7/8小胶质细胞产生的促炎介质，并增加星形胶质细胞谷氨酸转运体的表达。重要的是，INI-0602和PDE4抑制剂都可以减少包括AD和HD在内的许多疾病的炎症和神经元丢失。这项R21建议将通过评估对CLN3？EX7/8小鼠脑代谢、行为和神经元存活的影响，确定INI-0602和PDE4抑制剂的最佳神经保护方案。我们将为每种药物建立最佳的剂量-反应曲线，干预的理想治疗窗口，以及INI-0602和PDE4抑制剂在联合治疗方法中是否显示出相加效应。INI-0602和PDE4抑制剂作为延缓JNCL进展的新型疗法的临床前评估将用于以下特定目标：1)半通道抑制剂INI-0602可延缓JNCL早期的谷氨酸积累，导致丘脑皮质结构中神经元的显著保留；2)PDE4抑制剂通过减少促炎介质的释放和谷氨酸的积累而减少JNCL的神经元丢失；以及3)INI-0602和PDE4抑制剂的联合治疗因其不同的药物作用机制而提供更好的阻止JNCL进展的疗效。总之，我们新的化合物选择理论基础，支持INI-0602和PDE4抑制剂作为JNCL疗法的初步数据，以及JNCL对这些化合物的现有知识产权，为R21应用中概述的临床前试验奠定了坚实的基础。

DESCRIPTION (provided by applicant): Juvenile Neuronal Ceroid Lipofuscinosis (JNCL) is a lysosomal storage disease caused by an autosomal recessive mutation in the CLN3 gene. JNCL presents between 5-10 years of age, with progressive vision loss, seizures, cognitive and motor decline, and death by late teens-early 20s. There is no treatment for JNCL, which underscores the significance of identifying novel therapeutics to improve lifespan and quality-of-life for children suffering from this deadly disease. Recent work from our laboratory suggests that aberrant glial activation during early JNCL may contribute to neuronal loss. In particular, CLN3?ex7/8 microglia are primed to produce numerous proinflammatory mediators with known neurotoxic effects, whereas wild type (WT) cells are non-responsive. Astrocyte hemichannel (HC) opening is also enhanced in numerous brain regions of CLN3?ex7/8 mice, which allows the non-discriminant passage of molecules from the intra- to extracellular milieus and disruption of physiologic gradients. The combination of early HC opening and aberrant microglial activation in JNCL likely disrupts the brain metabolome, contributing to the pathological chain of events that culminates in neuronal loss. Our hypothesis is that targeting aberrant glial activation with two classes of compounds that affect multiple pathways will significantly delay JNCL progression. The first, INI-0602, is a novel HC inhibitor that reduces glutamate accumulation in CLN3?ex7/8 mice to levels typical of WT animals. The other group includes the second generation phosphodiesterase-4 (PDE4) inhibitors Roflumilast and PDE4 subtype specific inhibitors provided by Pfizer that attenuate proinflammatory mediator production by CLN3?ex7/8 microglia and also increase astrocyte glutamate transporter expression. Importantly, both INI-0602 and PDE4 inhibitors reduce inflammation and neuronal loss in numerous disorders, including AD and HD. This R21 proposal will identify the optimal neuroprotective regimens for INI-0602 and PDE4 inhibitors, by evaluating effects on the brain metabolome, behavior, and neuronal survival in CLN3?ex7/8 mice. We will establish optimal dose-response profiles for each drug, the ideal therapeutic window for intervention, and whether INI-0602 and PDE4 inhibitors display additive effects in a combinational therapy approach. The preclinical assessment of INI-0602 and PDE4 inhibitors as novel therapeutics to delay JNCL progression will be examined in the following specific aims: 1) The hemichannel inhibitor INI-0602 attenuates glutamate accumulation during early JNCL, leading to significant neuronal sparing in thalamocortical structures; 2) PDE4 inhibitors reduce neuronal loss in JNCL by attenuating proinflammatory mediator release and glutamate accumulation; and 3) A combinational therapy with INI-0602 and PDE4 inhibitor provides superior efficacy to impede JNCL progression due to distinct mechanisms of drug action. Together, our novel rationale for compound selection, supporting preliminary data for INI-0602 and PDE4 inhibitors as JNCL therapeutics, and existing intellectual property for these compounds in JNCL, form a solid foundation for the preclinical testing outlined in this R21 application.