提供治疗有效载荷的工程智能微生物正在成为治疗模式,特别是与胃肠道有关的疾病。肠出血性大肠杆菌(EHEC)是潜在致死性溶血性尿毒综合征的病原体。考虑到抗生素治疗会增加大肠杆菌产志贺毒素(Stx),导致全身性疾病的原因,需要新的补救措施。EHEC编码III型分泌系统(T3SS),其将Tir注入肠细胞。Tir插入宿主细胞膜,暴露一个随后结合内膜的胞外域,它的外膜蛋白之一,引发促进EHEC粘膜定植的附着和脱落(A/E)病变的形成。柠檬酸杆菌(Cr),一种天然的A/E小鼠病原体,其发病机制同样需要Tir和intiin。小鼠感染Cr(ΦStx2dact),一种用EHEC衍生的噬菌体溶解的变体,产生Stx2dact,发展肠道A/E病变和毒素依赖性疾病。Stx2a与人类疾病的关系更为密切。通过开发一种有效的方法来无缝地修改啮齿动物的基因组,我们生成了Cr_Tir-MEHEC(ΦStx2a),表达Stx2a和EHEC胞外Tir结构域的变体。我们发现用HS-PROT3EcT-TD4(一种人类共生大肠杆菌菌株(E.coliHS))进行小鼠预定殖,该菌株被设计为有效分泌抗EHECTir纳米抗体,用Cr_Tir-MEHEC(ΦStx2a)攻击后,细菌定植延迟,生存率提高。这项研究提供了第一个证据来支持工程共生大肠杆菌在肠道内递送阻断必需肠道病原体毒力决定因子的治疗性有效载荷的功效,一种可以作为抗生素非依赖性抗菌治疗方式的策略。
■分泌治疗剂的工程智能微生物正在成为治疗方式,特别是肠道疾病。随着多重耐药感染的威胁越来越大,迫切需要非抗生素治疗。胃肠道病原体肠出血性大肠杆菌(EHEC)可引起潜在致死性溶血性尿毒综合征,毒素驱动的疾病.鉴于人们担心抗生素会增加毒素释放,治疗主要限于支持治疗。这里,我们显示,用共生大肠杆菌(HS-PROT3EcT)进行预处理,以分泌阻断必需EHEC毒力因子的抗体,延迟小鼠EHEC样感染的建立.这项研究强烈表明,提供阻断肠道病原体定植因子的有效载荷的智能微生物可以被开发为对抗细菌感染的抗生素的急需替代品。
Engineered smart microbes that deliver therapeutic payloads are emerging as treatment modalities, particularly for diseases with links to the gastrointestinal tract. Enterohemorrhagic E coli (
EHEC) is a causative agent of potentially lethal hemolytic uremic syndrome. Given concerns that antibiotic treatment increases
EHEC production of Shiga toxin (Stx), which is responsible for systemic disease, novel remedies are needed.
EHEC encodes a type III secretion system (T3SS) that injects Tir into enterocytes. Tir inserts into the host cell membrane, exposing an extracellular domain that subsequently binds intimin, one of its outer membrane proteins, triggering the formation of attaching and effacing (A/E) lesions that promote EHEC mucosal colonization. Citrobacter rodentium (Cr), a natural A/E mouse pathogen, similarly requires Tir and intimin for its pathogenesis. Mice infected with Cr(ΦStx2dact), a variant lysogenized with an
EHEC-derived phage that produces Stx2dact, develop intestinal A/E lesions and toxin-dependent disease. Stx2a is more closely associated with human disease. By developing an efficient approach to seamlessly modify the C. rodentium genome, we generated Cr_Tir-MEHEC(ΦStx2a), a variant that expresses Stx2a and the
EHEC extracellular Tir domain. We found that mouse pre-colonization with HS-PROT3EcT-TD4, a human commensal E. coli strain (E. coli HS) engineered to efficiently secrete- an anti-EHEC Tir nanobody, delayed bacterial colonization and improved survival after challenge with Cr_Tir-MEHEC(ΦStx2a). This study provides the first evidence to support the efficacy of engineered commensal E. coli to intestinally deliver therapeutic payloads that block essential enteric pathogen virulence determinants, a strategy that may serve as an antibiotic-independent antibacterial therapeutic modality.