Preclinical testing of the splice modulating oligonucleotide LSP-GR1

描述(由申请人提供)：AMPA谷氨酸受体介导了中枢神经系统中大多数快速兴奋性神经传递。存在四个AMPA受体亚基，GluA1-GluA4，其功能通道包含这四个亚基的不同组合。AMPA受体表达失调在许多神经系统疾病中都有报道，包括肌萎缩侧索硬化症(ALS)，这是一种毁灭性的致命疾病，目前还没有很好的治疗方法。AMPA受体是交替剪接的，最具特性的剪接变体是Flip和Flop亚型。含有触发盒和触发盒的AMPA受体具有不同的通道特性。GluA1翻转和触发器变体具有相似的动力学，但翻转异构体对谷氨酸表现出更高的敏感性，从而增加突触增益。翻转通道的表达与兴奋性毒性和过度兴奋性的易感性有关。在ALS患者的运动神经元(MN)和该疾病的小鼠模型中发现GluA1触发器比率的增加。剪接调控寡核苷酸(SMO)与经典的反义寡核苷酸和siRNA相比具有独特的化学结构和明显的优势，目前正处于治疗肌营养不良症和脊髓性肌萎缩的临床试验中。我们已经开发出一种SMO，LSP-GR1，它可以在体内特异而有效地减少GluA1翻转。在ALS小鼠模型中，LSP-GR1可延长寿命并延缓疾病进展。我们第二阶段SBIR的目标是进行IND-Enabling临床前药理学/毒理学和CMC研究，为ALS患者的LSP-GR1临床测试奠定基础。将在大鼠和食蟹猴身上进行GLP药理学/毒理学研究，以评估毒性和生物分布。将进行化学、制造和控制(CMC)研究，以评估LSP-GR1的结构、稳定性和杂质。这些研究应该会产生支持IND的数据，使LSP-GR1能够进入ALS患者的临床测试。

DESCRIPTION (provided by applicant): AMPA glutamate receptors mediate the majority of fast excitatory neurotransmission in the central nervous system. Four AMPA receptor subunits exist, GluA1-GluA4, with functional channels containing various combinations of these four subunits. Dysregulation of AMPA receptor expression has been reported in many neurological disorders, including amyotrophic lateral sclerosis (ALS), a devastating and fatal disease for which no good treatment exists. AMPA receptors are alternatively spliced, with the best-characterized splice variants being the flip and flop isoforms. AMPA receptors containing flip vs. flop cassettes have distinct channel properties. GluA1 flip and flop variants have similar kinetics but the flip isoform shows greater sensitivity to glutamate, increasing synaptic gain. Expression of flip channels is associated with greater vulnerability to excitotoxicity and hyperexcitability. Increases in GluA1 flip to flop ratio are found in motor neurons (MNs) of ALS patients and in a mouse model of the disease. Splice modulating oligonucleotides (SMOs) have unique chemistries and distinct advantages over classic antisense oligonucleotides and siRNA, and are in clinical trials for treating muscular dystrophy and spinal muscular atrophy. We have developed an SMO, LSP-GR1, that specifically and potently reduces GluA1 flip in vivo. LSP-GR1 increases longevity and delays disease progression in a mouse model of ALS. The goal of our Phase II SBIR is to perform IND- enabling preclinical pharmacology/toxicology and CMC studies to set the stage for clinical testing of LSP-GR1 in ALS patients. GLP pharmacology/toxicology studies will be done in rats and cynomologus monkeys to evaluate toxicity and biodistribution. Chemistry, Manufacturing and Controls (CMC) studies will be done to evaluate structure, stability, and impurities of LSP- GR1. These studies should lead to IND-enabling data to allow LSP-GR1 to move forward to clinical testing in ALS patients.