Optimization of compounds to improve mRNA splicing in familial dysautonomia

描述(申请人提供)：家族性自主神经障碍(FD)是一种遗传性感觉和自主神经病变，由IKBKAP基因的剪接突变引起。该突变导致IKBKAP基因外显子20的可变跳跃，从而导致IKAP蛋白的组织特异性减少。对FD患者组织的分析显示，神经元组织中有明显更多的外显子跳跃，因此IKAP水平较低。IKAP是人类Elongator复合体的成员，该复合体是有效转录延长一组基因所必需的。尽管FD是隐性的，但我们已经证明患者保留了制造正常mRNA和蛋白质的能力。这一发现为开发旨在通过剪接修饰提高细胞IKAP水平的疗法提供了一种令人兴奋的、直接的方法。作为NINDS赞助的神经退行性药物筛选联盟的一部分，我们发现，用植物细胞分裂素激动素处理培养的FD细胞，可以增强外显子-20-包含，并显著增加FD细胞中野生型IKBKAP mRNA和IKAP蛋白的数量。该化合物具有显著的疗效，可以在培养一周内恢复患者细胞中正常的IKAP蛋白水平。我们已经证明了激动素在各种细胞类型中以及在人类细胞中使用微型基因分析改变IKBKAP剪接的能力。最近，我们在转基因小鼠和人类FD携带者身上都显示出了体内的疗效。尽管DysAutonomia基金会在开发激动素作为治疗FD的潜在药物方面投入了大量资金，但通往临床的道路一直很缓慢，我们仍在研究最初确定的化合物。我们最近产生了一些有希望的结构和活性关系(SAR)数据，表明先导化合物激动素的活性可以提高。为了提高激动素的效力和活性，进行化学优化是至关重要的，而时间是关键。尽管FD是一种发育障碍，但患者一生中都受到持续的、剧烈的神经元变性的困扰。有效地提高生命早期的IKAP水平可能有助于神经元存活和 防止或延缓患者随着年龄增长而出现的令人衰弱的步态以及感觉和认知能力下降。蓝图神经治疗网络为药物开发提供了一个独特的机会，它将提供访问目前无法获得的资源的途径。

DESCRIPTION (provided by applicant): Familial dysautonomia (FD) is a hereditary sensory and autonomic neuropathy that is caused by a splice mutation in the IKBKAP gene. The mutation results in variable skipping of exon 20 in IKBKAP mRNA, which leads to a tissue-specific reduction of IKAP protein. Analysis of tissues from FD patients shows significantly more exon-skipping in neuronal tissue, and therefore lower IKAP levels. IKAP is a member of the human Elongator complex, which is required for efficient transcriptional elongation of a subset of genes. Despite the fact that FD is recessive, we have shown that patients retain the capacity to make both normal mRNA and protein. This discovery offers an exciting, direct approach towards the development of therapies aimed at increasing levels of cellular IKAP via splicing modification. As part of the NINDS-sponsored Neurodegeneration Drug Screening Consortium, we found that treatment of cultured FD cells with kinetin, a plant cytokinin, enhances exon-20-inclusion and dramatically increases the amount of wild-type IKBKAP mRNA and IKAP protein in FD cells. This compound has remarkable efficacy and can restore normal IKAP protein levels in patient cells within one week in culture. We have demonstrated kinetin's ability to alter IKBKAP splicing using minigene assays in a variety of cell types, as well as in human cells. More recently, we have shown in vivo efficacy in both transgenic mice and in human FD carriers. Despite substantial investment by the Dysautonomia Foundation in developing kinetin as a potential treatment for FD, the road to the clinic has been slow, and we are still working with the originally identified compound. We have recently generated some promising SAR (structure and activity relationship) data showing that the activity of the lead compound kinetin can be improved. It is crucial that chemical optimization be performed in order to improve the potency and activity of kinetin, and time is of the essence. Despite the fact that FD is a developmental disorder, patients are plagued by continued, drastic neuronal degeneration throughout life. Effectively increasing IKAP levels early in life may support neuronal survival and prevent or delay the debilitating gait and sensory and cognitive decline seen in patients as they age. The Blueprint Neurotherapeutics Network offers a unique opportunity for drug development that will provide access to resources that are currently out of reach.