Genetically Encoded Biosafety in a Therapeutically Modified Organism for Obesity

摘要/概要 2.4亿美国人和全球20亿人肥胖或超重;这是一个 主要的健康问题，与心脏病，癌症和糖尿病有关。肥胖已 被证明很难治疗，但工程微生物显示出希望。E.大肠杆菌工程改造， 产生N-酰基磷脂酰乙醇胺（NAPE）导致饱腹感增加， 肥胖者的食物摄入量减少，体脂减少，胰岛素抵抗降低 小鼠不幸的是，这种生物缺乏安全和遏制措施， 其临床评价和在人类中的使用。解决控制问题的强大生物安全解决方案 和控制问题将释放这种微生物的治疗潜力。 最佳的解决方案可能是合成营养缺陷型生物： 存在互补配体（ligand）。主要研究者（洛佩斯博士） 展示了一种方法，用于产生合成的营养缺陷型的基础上合成 配体依赖性必需基因（SLiDE等位基因）。SLiDE菌株是理想的生物安全 解决方案，因为他们确保工程生物可以通过去除 配体。它们还可以通过要求生物体进入环境来防止生物体逃逸 生物体只在有配体的地方生长这将广泛地使使用 通过提供通用的、可靠的生物安全技术， 将NAPE生产并入SLiDE生物安全菌株中将产生治疗性 生物具有内在的生物安全性，但SLiDE生物的配体依赖性必须 将其改变为食品安全化合物用于患者。这将通过应用 定向进化迫使SLiDE菌株用食品安全配体控制其生存能力 而忽略了自然界和肠道中发现的其他化合物。本一期产品 格兰特，NAPE生产SLiDE菌株，需要食品安全的配体， 可行性，将代表开发抗肥胖治疗的关键一步 可安全用于患者。抗肥胖功效与 前所未有的能力，防止治疗生物体逃逸和关闭， 按需治疗将是工程益生菌的有价值的成就。的 在这项研究中产生的最有前途的菌株将是进一步表征的理想选择， 第二阶段的体内试验，着眼于最终的临床试验。

Abstract / Summary 240 million Americans and 2 billion people worldwide are obese or overweight; this is a major health concern, associated with heart disease, cancer, and diabetes. Obesity has proven difficult to treat, but engineered microbes show promise. E. coli engineered to produce N-acyl phosphatidylethanolamines (NAPEs) resulted increased satiety, decreased food intake, decreased body fat, and decreased insulin resistance in obese mice. Unfortunately, lack of safety and containment measures in this organism precludes its clinical evaluation and use in humans. A robust biosafety solution to address control and containment concerns would unlock the therapeutic potential of this organism. The optimal solution may be synthetic auxotrophs: organisms engineered to require the presence of a complementing ligand (ligand). The principal investigator (Dr. Lopez) demonstrated a method for generating synthetic auxotrophs based on a Synthetic Ligand-Dependent Essential gene (SLiDE allele). SLiDE strains are an ideal biosafety solution because they ensure engineered organisms can be “turned off” by removing the ligand. They also prevent organisms from escaping into the environment by requiring that organisms only grow where ligand is supplied. This will broadly enable the use of therapeutic organisms by providing a versatile, reliable biosafety technology. Incorporation of NAPE production into SLiDE biosafety strains will produce a therapeutic organism with intrinsic biosafety, but the ligand-dependence of the SLiDE organism must be altered to food-safe compounds for use in patients. This will be achieved by applying directed evolution to force the SLiDE strain to control its viability with food-safe ligands and ignore other compounds found in nature and the gut. The products of this Phase I grant, NAPE-producing SLiDE strains that require food-safe ligands for continued viability, would represent a critical step in developing an anti-obesity therapeutic organism safe for use in patients. The combination of anti-obesity efficacy with the unprecedented ability to prevent therapeutic organisms from escaping and turn off therapy on demand would be a valuable achievement for engineered probiotics. The most promising strains generated in this study will be ideal for further characterization in vivo in Phase II, with an eye towards eventual clinical trials.