Ion Channel Drug Discovery Using Photoswitch Technology

描述（由申请人提供）：离子通道是允许带电分子通过细胞膜选择性运动的膜蛋白。许多疾病状态，如囊性纤维化、肌肉营养不良、高血压和心律失常都是由离子通道病变引起的。离子通道已被药物发现界确定为治疗干预的优秀靶点，但由于开发高质量、高通量功能离子通道检测所涉及的技术障碍，“离子通道药物”的开发一直令人失望。光开关生物科学公司已经开发出一种技术，可以将小型纳米机器连接到离子通道上，从而通过光对这些蛋白质进行快速可逆的控制。该项目的三个具体目标是：(1)优化哺乳动物细胞系中由光电通道驱动的膜电位变化的动态范围；(2)优化细胞系、光电通道和膜电位范围，以利用电生理检测检测几种电压门控离子通道目标；(3)通过用指示染料替代电生理检测，将分析转换为全光读出。第一批商业化产品将是全光离子通道检测和高通量离子通道药物发现仪器。与现有技术相比，使用全光技术进行离子通道分析有几个优点：(1)消除了用于通道激活的液体添加，(2)对于高通量离子通道药物发现具有高度可扩展性，(3)每个数据点的价格至少比自动电生理学低100倍，(4)通道激活几乎比添加KCl快100倍。这种新的离子通道测定技术最重要的优点是能够快速可靠地控制膜电位。这种对膜电位的控制允许开发可扩展的高通量状态依赖分析，这在当前技术下是不可能的。这项突破性的技术将最终允许充分利用离子通道作为药物靶点。

DESCRIPTION (provided by applicant): Ion channels are membrane proteins that allow the selective movement of charged molecules through cellular membranes. Many disease states, such as cystic fibrosis, muscular dystrophies, hypertension, and cardiac arrhythmias are caused by ion channel pathologies. Ion channels have been identified by the drug discovery community as excellent targets for therapeutic intervention but because of the technical hurdles involved in developing quality, high-throughput functional ion channel assays, the development of "ion channel drugs" has been disappointing. Photoswitch Biosciences has developed technology, which allows attaching small nanomachines to ion channels enabling rapid and reversible control of these proteins by light. The three Specific Aims of the proposed project are: (1) optimization of the dynamic range of changes in membrane potential driven by photoswitched channels in mammalian cell lines, (2) optimization of cell line, photoswitched channel and membrane potential range to assay several voltage-gated ion channel targets using electrophysiological detection, and (3) conversion of the assay to an all-optical readout by substituting indicator dyes for electrophysiology detection. The first commercial products to be developed will be all-optical ion channel assays and instruments for high- throughput ion channel drug discovery. The use of all-optical technology for ion channel assays has several advantages over existing techniques: (1) Elimination of liquid additions for channel activation, (2) Highly scalable for high-throughput ion channel drug discovery, (3) Price per datapoint is at least 100X less than automated electrophysiology, (4) Channel activation is almost 100X faster than KCl addition. The most important benefit of this new ion channel assay technology is the ability to rapidly and reliably control membrane potential. This control of membrane potential allows for the development of scalable high-throughput state-dependent assays, which is impossible with current technology. This breakthrough technology will finally allow the full exploitation of ion channels as drug targets. PUBLIC HEALTH RELEVANCE: Many diseases involve problems with the functioning of membrane proteins called ion channels. These proteins are responsible for proper operation of the nervous system, the muscles, and virtually all other physiological events. Drugs that affect ion channel behavior have been developed for a variety of diseases, including heart problems, cystic fibrosis, and other diseases. Ion channels are difficult to study and, because of this, drugs directed at ion channels have been difficult to find. Photoswitch Biosciences proposes to develop methods to increase the ability to study ion channels, and, thus, to increase the number of ion channel drugs.