Therapeutic mechanisms of L. lactis-mediated wound repair

项目总结： 广泛使用有益细菌来促进肠道健康和抑制炎症， 尽管实验证据证实了许多细菌的有效性，但这种说法促进了这种说法 仍然是有限的。我们通过鉴定一种新鉴定的有益细菌直接解决了这一差距 有效抑制损伤引起的肠道炎症。在对潜在有益细菌的筛选中，我们 鉴定出乳酸乳球菌亚种。乳杆菌作为一种细菌，在人体内具有很强的抗炎活性 小鼠的肠子。为了证实使用这种菌株作为治疗IBD的药物，这是必需的 ‘早期临床试验与活的生物治疗产品’，我们将采取严格的方法，以产生关键的预 临床资料采用相关的小鼠结肠炎模型。我们的初步数据显示，乳酸乳杆菌的摄食会引起 在慢性DSS治疗期间较低的疾病活动指数(DAI)评分，以及显著更快的 在取消直接资助计划后的恢复。从机制上讲，我们发现乳酸乳杆菌激活了细胞保护作用 Nrf2在肠道组织中的信号转导途径，表明乳酸乳杆菌介导的保护作用，或称Nrf2基因 在TLR2和MyD88缺失的小鼠中不会发生激活。重要的是，乳酸乳杆菌的培养上清是足够的。 在体外培养的上皮细胞创伤愈合模型中加速愈合，表明 乳酸乳杆菌分泌的一种因子产生了有益的效果。因为与乳酸乳杆菌有亲缘关系的ATCC 菌株不会产生同样的有益效果，我们假设有一种特定的因素，细菌 乳酸乳杆菌中的胞外多糖负责诱导其强大的抗炎和促修复作用 通过MyD88依赖的信号通路发挥作用。此外，我们还展示了乳酸乳杆菌激活细胞外基质的初步数据。 肠道组织中与NRF2调控相关的一组特定microRNAs的表达 通路信号。因此，我们的中心假设是乳酸乳杆菌释放的特异元素(S) 在肠道中诱导细胞保护和抗炎作用，并可以调节肠道的病理生物学 IBD。我们将在以下具体目标中检验我们的假设：(1)表征 乳酸乳杆菌亚种。乳杆菌在结肠炎中的作用，(2)鉴定乳酸乳杆菌亚种产生和释放的因子。奶油 诱导其有益效应并激活NRF2信号，以及(3)确定关键乳酸杆菌的作用 亚种。克雷莫里斯诱导的调控NRF2信号的microRNAs在调节L. 乳酸菌亚种。奶油。我们共同确定了一种有益于影响宿主的效应器微生物 表型，对抑制结肠炎引起的炎症有明显的有利作用。我们将会发现 潜在的作用机制，这已成为微生物组研究的焦点，并且对 以微生物区系为基础的疗法的发展。我们打算为乳乳杆菌的使用产生足够的数据 亚种。乳膏用于治疗以异常炎症为表现的消化系统疾病的临床试验。

PROJECT SUMMARY: The use of beneficial bacteria to promote intestinal health and to limit inflammation is widely practiced, although experimental evidence corroborating the efficacy of many bacteria promoted with such claims remains limited. We directly address this gap by identifying a newly characterized beneficial bacterium that potently dampens injury-induced intestinal inflammation. In a screen of potential beneficial bacteria, we identified Lactococcus lactis subsp. cremoris as a bacterium that elicited potent anti-inflammatory activity in the mouse intestine. In order to substantiate the use of this strain as a therapeutic to treat IBD, which is required ‘Early Clinical Trial with Live Biotherapeutic Products’, we will take a rigorous approach to generate critical pre- clinical data using relevant mouse models of colitis. Our preliminary data show that feeding of L. lactis elicits lower Disease Activity Index (DAI) scores during chronic DSS treatment, and a significantly faster rate of recovery following the withdrawal of DSS. Mechanistically, we show that L. lactis activates the cytoprotective NRF2 signaling pathway in intestinal tissue, and show here that L. lactis-mediated protection, or Nrf2 gene activation does not occur in Tlr2 & Myd88-null mice. Importantly, culture supernatant of L. lactis was sufficient to accelerate healing in an in vitro epithelial cell wound healing model in cultured epithelial cells, indicating that a factor secreted by L. lactis elicits the beneficial effects. Because phylogenetically related L. lactis ATCC strains do not elicit the same beneficial effects, we hypothesize that a specific factor, bacterial exopolysaccharide, within L. lactis is responsible for eliciting its powerful anti-inflammatory and pro-restitutive effects via MyD88-dependent signaling. In addition, we show novel preliminary data that L. lactis activates the expression of a specific set of microRNAs in intestinal tissue that are associated with the regulation of NRF2 pathway signaling. Therefore, our central hypothesis is that the specific element(s) released by L. lactis induces cytoprotective and anti-inflammatory effects in the intestine, and can modulate the pathobiology of IBD. We will test our hypothesis in the following specific aims: (1) to characterize the pro-restitutive effects of L. lactis subsp. cremoris in colitis, (2) to identify the factor produced and released by L. lactis subsp. cremoris that induces its beneficial effects and activates NRF2 signaling, and (3) to determine the role of key L. lactis subsp. cremoris-induced microRNAs that regulate NRF2 signaling in modulating the cytoprotective effects of L. lactis subsp. cremoris. Together, we identify an effector microorganism that beneficially influences host phenotype, with clear favorable effects on dampening colitis-induced inflammation. We will discover the underlying mechanisms of action, which has become foci of microbiome research, and which is essential for the development of microbiota-based therapeutics. We intend to generate sufficient data for the use of L. lactis subsp. cremoris in clinical trials to treat digestive diseases manifested by aberrant inflammation.