Development of therapeutic GABA-producing bacteria

这个项目的目标是开发治疗内脏疼痛（肠易激综合征的一种症状 - IBS）、抑郁或焦虑。IBS影响 占美国人口的10-20%。抑郁症每年影响美国高达9%的成年人， 据估计，焦虑影响着10-29%的人。治疗IBS的药物有限， 50%的抑郁症或焦虑症患者对一线药物无反应，凸显了探索的必要性 新的治疗方式。新疗法的一个潜在来源是肠道微生物组-细菌， 存在于胃肠道中。这些共生有机体已经被证明参与了许多 健康和疾病的组成部分，包括神经发育，大脑发育和情绪。一个关键 沿着肠-脑-轴的沿着通信的机制是肠道细菌对神经递质的调节。 有趣的是微生物组产生神经递质GABA水平的能力。GABA是主要的 哺乳动物中枢神经系统中的抑制性神经递质和低水平和/或GABA能 失调与许多疾病有关，包括IBS、抑郁症、应激和大脑改变 发展肠道细菌已被证明能产生GABA，无菌动物的GABA水平降低， 对人体的微生物组干预可以改变血清GABA水平，这表明微生物组有助于 到主机级别。重要的是，在啮齿动物中进行的能够产生GABA的细菌的干预性研究， 在改善焦虑、抑郁和内脏疼痛症状以及调节 大脑中的GABA能活性，表明微生物来源的GABA很重要。然而，这些前 努力未能从人类肠道中鉴定出大量能够以100%的浓度产生GABA的细菌。 人体胃肠道的生理相关pH值（5.7-7.4），这可能是对胃肠道疾病贡献最大的微生物。 宿主GABA水平和/或GABA能活性。在我们的初步研究中，我们开发了一种屏幕来识别 一种能够在生理相关pH下产生GABA的新型GABA产生细菌，发现了一些 这些生物表达与健康人GABA产生有关的基因， 患有抑郁症和IBS的人在本提案的第一阶段，GABA生产、安全和 将研究这些菌株的发育概况。显示出强大发育潜力的菌株 然后将围绕这些标准在人类肠道模拟器模型中引入候选治疗联合体中 研究在模拟人类社区中的植入和GABA生产能力。财团展示 在肠道模拟器中的强有力的结果，然后将在试点大鼠研究中进行测试，以评估它们增加水平的能力， 改变GABA能反应，然后移植。成功调节GABA/GABA能 GABA产生细菌的活性将为探索治疗功效提供原理证据， 在内脏疼痛、抑郁和焦虑的动物模型中的第2阶段机制验证。

The goal of this project is to develop therapeutics to treat visceral pain (a symptom of irritable bowel syndrome – IBS), depression or anxiety by delivering bacteria capable of altering host GABAergic activity. IBS affects between 10-20% of the U.S. population. Depression affects up to 9% of adults in the U.S. per year, with anxiety affecting an estimated 10-29% of people in their lifetime. There are limited drugs for IBS, and roughly 50% of patients with depression or anxiety do not respond to front-line drugs, highlighting the need to exploring new therapeutic modalities. One potential source of new therapeutics is the gut microbiome – the bacteria that reside in the gastrointestinal tract. These symbiotic organisms have been shown to be involved in numerous components of health and disease, including neurodevelopment, brain development, and mood. A key mechanism for communication along the gut-brain-axis is the modulation of neurotransmitters by gut bacteria. Of interest is the ability of the microbiome to produce levels of the neurotransmitter GABA. GABA is the major inhibitory neurotransmitter in the mammalian central nervous system and low levels and/or GABAergic dysregulation are associated with numerous diseases, including IBS, depression, stress, and altered brain development. Gut bacteria have been shown to produce GABA, germ-free animals have reduced GABA levels, and microbiome intervention in humans can alter serum GABA levels, suggesting the microbiome contributes to host levels. Importantly, interventional studies in rodents with bacteria capable of producing GABA has showed efficacy in improving symptoms of anxiety, depression, and visceral pain, as well as modulating GABAergic activity in the brain, suggesting microbial derived GABA is important. However, these previous efforts have failed to identify abundant bacteria from the human gut capable of producing GABA at a physiologically relevant pH for the human GI tract (5.7-7.4), which are likely the organisms contributing most to host GABA levels and/or GABAergic activity. In our preliminary studies, we developed a screen to identify novel GABA producing bacteria, capable of producing GABA at a physiologically relevant pH, found some of these organisms express genes involved with GABA production in healthy people, and are reduced in individuals with depression and IBS. In Phase 1 of this proposal, the GABA-producing, safety, and development profiles of these strains will be examined. Strains shown to exhibit strong developmental potential around these criteria will then be introduced in candidate therapeutic consortia in a human gut simulator model to study engraftment and GABA production capabilities in a mock human community. Consortia showing strong results in the gut simulator will then be tested in a pilot rat study to assess their ability to increase levels of systemic GABA, alter the GABAergic response, and engraft. Successful modulation of GABA/GABAergic activity by GABA producing bacteria will provide proof of principle to explore therapeutic efficacy and mechanism validation in Phase 2 in animal models of visceral pain, depression, and anxiety.