Insights on gastrointestinal motility through the use of optogenetic sensors and actuators.
Insights on gastrointestinal motility through the use of optogenetic sensors and actuators.
复制标题
通过使用光遗传学传感器和致动器对胃肠动力的见解。
DOI：
10.1113/jp281930
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发表时间：
2022-07
影响因子：
5.5
通讯作者：
Baker, Salah A.
中科院分区：
文献类型：
--
作者：
Drumm, Bernard T.;Cobine, Caroline A.;Baker, Salah A.
关键词：
胃肠道（GI）的肌层由平滑肌细胞（SMC）和各种Cajal间质细胞（ICC）群、血小板源性生长因子受体α+（PDGFRα+）细胞以及兴奋性和抑制性肠运动神经组成。SMC、ICC和PDGFRα+细胞形成电偶联的合胞体，其与来自肠神经系统（ENS）的输入一起调节GI运动。早期评估胃肠道中Ca2+信号传导行为的研究依赖于用Ca2+染料不加选择地加载组织。这些方法缺乏研究特定目标细胞中活性而不会遇到制剂中其他细胞污染的手段。表达光遗传学传感器（GCaMP，RCaMP）的小鼠的发展允许以细胞特异性方式可视化Ca 2+信号传导行为。此外，表达光遗传学调节剂（通道视紫红质或盐视紫红质）的小鼠的可用性允许使用光操纵特定的信号传导途径。表达GCaMP的动物已被用于表征整个GI肌肉组织中不同类别的ICC和SMC的Ca 2+信号传导行为。这些发现说明了ICC中的Ca2+信号传导如何在GI肌肉中发挥重要作用，有助于括约肌的张力，节律肌肉中的起搏器活动并将肠道信号传递给SMC。在特定神经元群体中表达通道视紫红质的动物已被用于映射神经回路并检查对GI运动的连接后神经效应。因此，光遗传学方法提供了一种新的手段来检查特定细胞类型对复杂多细胞系统内运动模式的调节的贡献。光遗传激活剂和传感器可用于研究胃肠道（GI道）复杂的多细胞性质。由光激活的光遗传激活剂如通道视紫红质（ChR2）、OptoXR和盐视紫红质（HR）蛋白可以被遗传编码到特定的细胞类型中。这可用于直接激活或沉默特定GI细胞，例如各种类型的肠神经元、平滑肌细胞（SMC）或间质细胞，例如Cajal间质细胞（ICC）。由不同波长的光如绿色钙调蛋白融合蛋白（GCaMP）和红色钙调蛋白（RCaMP）激活的光遗传传感器使得在特定细胞类型的完整组织内的亚细胞Ca 2+信号传导的高分辨率成为可能。这些工具可以提供无与伦比的深入了解胃肠道运动和神经支配的机制。
The muscularis of the gastrointestinal (GI) tract consists of smooth muscle cells (SMCs) and various populations of interstitial cells of Cajal (ICC), platelet-derived growth factor receptor α+ (PDGFRα+) cells, as well as excitatory and inhibitory enteric motor nerves. SMCs, ICC and PDGFRα+ cells form an electrically coupled syncytium, which together with inputs from the enteric nervous system (ENS) regulate GI motility. Early studies evaluating Ca2+ signalling behaviours in the GI tract relied upon indiscriminate loading of tissues with Ca2+ dyes. These methods lacked the means to study activity in specific cells of interest without encountering contamination from other cells within the preparation. Development of mice expressing optogenetic sensors (GCaMP, RCaMP) has allowed visualization of Ca2+ signalling behaviours in a cell specific manner. Additionally, availability of mice expressing optogenetic modulators (channelrhodopsins or halorhodospins) has allowed manipulation of specific signalling pathways using light. GCaMP expressing animals have been used to characterize Ca2+ signalling behaviours of distinct classes of ICC and SMCs throughout the GI musculature. These findings illustrate how Ca2+ signalling in ICC is fundamental in GI muscles, contributing to tone in sphincters, pacemaker activity in rhythmic muscles and relaying enteric signals to SMCs. Animals that express channelrhodopsin in specific neuronal populations have been used to map neural circuitry and to examine post junctional neural effects on GI motility. Thus, optogenetic approaches provide a novel means to examine the contribution of specific cell types to the regulation of motility patterns within complex multi-cellular systems. Optogenetic activators and sensors can be used to investigate the complex multi-cellular nature of the gastrointestinal (GI tract). Optogenetic activators that are activated by light such as channelrhodopsins (ChR2), OptoXR and halorhodopsinss (HR) proteins can be genetically encoded into specific cell types. This can be used to directly activate or silence specific GI cells such as various classes of enteric neurons, smooth muscle cells (SMC) or interstitial cells, such as interstitial cells of Cajal (ICC). Optogenetic sensors that are activated by different wavelengths of light such as green calmodulin fusion protein (GCaMP) and red CaMP (RCaMP) make high resolution of sub-cellular Ca2+ signalling possible within intact tissues of specific cell types. These tools can provide unparalleled insight into mechanisms underlying GI motility and innervation.