Gut commensal to enteric neuron communication: how ingstion of a lactobacillus species modulates intrinsic sensory neuron excitability and potassium ion channel properties

肠道充满了微生物（共生体），它们与宿主有互利的共生关系。共生体参与维持肠道表面细胞的完整性，帮助吸收食物，调节免疫系统。一些共生生物，当被摄入时（益生菌）提供营养，促进正常的肠道运动，如果存在，也可以减少宿主的炎症。越来越明显的是，这些微生物与其宿主之间的相互作用比以前认为的要复杂得多，而且越来越多的证据表明，一些共生体可以直接影响宿主的神经系统。例如，某些特定的益生菌物种会改变自主神经反射，即连接肠道和中枢神经系统的神经纤维的活动。益生菌甚至可以改变大脑活动，包括情绪和焦虑。共食信号如何直接传递到神经系统一直是个谜。我们现在已经发现了第一个证据，证明一种特定种类的产酸益生乳杆菌可以靶向一种肠道感觉神经细胞中的离子通道分子的活性。这一令人惊讶的发现为理解某些共生体如何与宿主神经系统的一部分对话提供了重要的线索；揭开共生体如何与神经系统不同部分沟通的途径的必要的第一步。我们设计了一系列的生理实验来揭示微生物向这些感觉神经细胞发出信号的途径和分子化学机制。这些实验的结果将为细菌和动物之间的正常生理信号传递提供第一个详细的描述。这项工作将扩展到其他微生物物种和宿主神经系统的组成部分，以确定共生生态系统如何与宿主神经系统相互作用，以促进细菌和宿主之间的稳态关系。

The intestine is filled with microorganisms (commensals) that have mutually beneficial symbiotic relationship with their host. Commensals are involved in maintaining the integrity of the cells lining the gut surface, aiding in absorption of foodstuffs, and conditioning the immune system. Some commensal organisms, when ingested (probiotics) provide nutrients, facilitate normal intestinal motility, and may also reduce inflammation in the host if present. It is becoming evident that the interaction between these microorganisms and their hosts is more complex than previously thought and evidence is being accumulated that some commensals can affect directly the host nervous system. For example certain specific probiotic species alter autonomic nerve reflexes, the activity of nerve fibres connecting the intestine with the central nervous system. Probiotics may even alter brain activity including mood and anxiety. How the commensal signal directly to the nervous system has been a mystery. We have now found the 1st evidence that a particular species of acid producing Lactobacillus probiotic can target the activity of an ion channel molecule in a single type of intestinal sensory nerve cell. This surprising discovery provides a significant lead to the understanding of how certain commensals could talk to a part of the host nervous system; a necessary 1st step in unraveling the paths of how commensals communicate with different parts of the nervous system. We have designed a series of physiological experiments that will uncover the routes and molecular chemical mechanisms by which the microorganism signals to those sensory nerve cells. The results from these experiments will provide the 1st detailed description for the steps involved into normal physiological signaling between the bacterial and animal Kingdom. This work will then be expanded to involve other microbe species and components of the host nervous system to determine how the commensal ecosystem interacts with the host nervous system to facilitate a homeostatic relationship between the bacteria and their hosts.