Development of neuroprotective PDZ-domain inhibitors for the treatment of MS

描述(申请人提供)：多发性硬化症(MS)的特征是免疫学和炎症性变化，导致神经纤维脱髓鞘和神经细胞死亡。虽然MS是一种典型的原发脱髓鞘疾病，但越来越多的证据表明，神经元变性也发生在MS中，有助于获得持续的临床缺陷。MS的主要特征可以在实验性自身免疫性脑脊髓炎(EAE)的动物模型上复制。降低神经元和少突胶质细胞上表达的NMDA或海人酸亚型谷氨酸受体(NMDAR，KAR)活性的药物可以抑制EAE。在这项提案中，一种新的环肽化合物CN2097将被测试其改善MS样症状和病理的能力。这种化合物结合突触后密度蛋白PSD-95的PDZ结构域，破坏其与KAR和NMDAR亚型的相互作用。PSD-95作为连接KARs和JNK激活的分子支架，在红藻氨酸介导的兴奋性毒性中起着关键作用。NMDA诱导的细胞死亡与PSD-95与CaMKII、nNOS和其他主要细胞死亡信号蛋白的关联有关。在体内视网膜毒性模型中，CN2097完全阻断了NMDA诱导的细胞死亡。目的1在体内视网膜毒性模型中，以及在体外皮质神经元和视网膜少突胶质细胞中，研究该化合物在减轻红藻氨酸诱导的细胞死亡方面的信号通路和作用。目的2利用模拟MS的髓鞘少突胶质细胞糖蛋白实验性自身免疫性脑脊髓炎(MOG-EAE)动物模型，确定CN2097是否能增加视神经和脊髓神经的存活和功能。我们推测，这种PDZ结构域抑制剂将提高对治疗的耐受性，因为它似乎不干扰正常的NMDA或AMPA受体活性，同时改善与疾病相关的兴奋性毒性损伤。与公共健康相关：最近的研究表明，谷氨酸受体在神经细胞之间的信号传递中起着重要作用，也增加了多发性硬化症患者对神经元死亡和髓鞘少突胶质细胞死亡的敏感性。我们已经合成了一系列高亲和力的化合物，这些化合物完全可以防止神经元死亡，预计可以提高治疗的耐受性，因为它们不会影响谷氨酸受体在神经之间传递信号的能力，同时防止疾病相关的损伤。这项研究拨款的中心目标是更好地了解我们最有希望的化合物(CN2097)的作用，并确定其作为治疗多发性硬化症的新治疗方法的潜力。

DESCRIPTION (provided by applicant): Multiple sclerosis (MS) is characterized by immunological and inflammatory changes that contribute to demyelination of nerve fibers and neuronal cell death. Although MS is a prototypic primary demyelinating disease, increasing evidence indicates that neuronal degeneration also occurs in MS, contributing to the acquisition of nonremitting clinical deficits. The main features of MS can be reproduced in an animal model, experimental autoimmune encephalomyelitis (EAE). Drugs that reduce the activity of the NMDA or Kainate subtypes of glutamate receptors (NMDAR, KAR), which are expressed both on neurons and oligodendrocytes, suppress EAE. In this proposal, a novel cyclic peptide compound, CN2097, will be tested for its ability to ameliorate MS-like symptoms and pathology. This compound binds the PDZ-domain of the postsynaptic density protein, PSD-95, disrupting its interaction with KAR and NMDAR subtypes. PSD-95 plays a critical role in kainate-mediated excitotoxicity by acting as a molecular scaffold to link KARs to JNK activation. NMDA-induced cell death is linked to the association of PSD-95 with CaMKII, nNos and other primary cell death signaling proteins. In an in vivo retinal toxicity model CN2097 completely blocked NMDA-induced cell death. Aim 1 will examine the signaling pathways and the effects of this compound on attenuating kainate-induced cell death in an in vivo retinal toxicity model, as well as in cortical neurons and retinal oligodendrocytes in vitro. Aim 2 will determine whether CN2097 can increase the survival and function of optic and spinal cord nerves using a MS animal model, myelin oligodendrocyte glycoprotein-experimental autoimmune encephalomyelitis (MOG-EAE), that emulates MS. Testing the neuroprotective effects of CN2097 in EAE rats is of clinical relevance in slowing or reversing MS-related neurological disability. We hypothesize that this PDZ-domain inhibitor will improve the tolerance for the treatment because it does not appear to interfere with normal NMDA or AMPA receptor activity, while ameliorating the disease related excitotoxic damage. PUBLIC HEALTH RELEVANCE: Recent studies show that glutamate receptors, which are important in transmitting signals from one nerve cell to another, also increase sensitivity to the death of neurons and myelinating oligodendrocytes in multiple sclerosis. We have synthesized a series of high affinity compounds that completely prevent neuronal death and are predicted to improve the tolerance for treatment because they do not affect the ability of glutamate receptors to signal between nerves, while preventing the disease related damage. The central goal of this research grant is to better understand the action of our most promising compound (CN2097) and to determine its potential as a new therapeutic approach for treating multiple sclerosis.