Jafari Nazila V, Kuehne Sarah A, Minton Nigel P, Allan Elaine, Bajaj-Elliott Mona
Infection, Immunity, Inflammation and Physiological Medicine, Institute of Child Health, University College London, London, UK.
Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University of Nottingham, Nottingham, UK; NIHR Biomedical Research Unit in Gastrointestinal and Liver Diseases at Nottingham University Hospitals NHS Trust, University of Nottingham, Nottingham, UK.
Anaerobe. 2016 Feb;37:96-102. doi: 10.1016/j.anaerobe.2015.12.007. Epub 2015 Dec 19.
Clostridium difficile infection is one of the leading causes of healthcare associated diarrhoea in the developed world. Although the contribution of C. difficile toxins to disease pathogenesis is now well understood, many facets of host-pathogen interactions between the human intestinal epithelia and the C. difficile bacterium that may contribute to asymptomatic carriage and/or clinical disease remain less clear. Herein, we tested the hypothesis that C. difficile strains mediate intestinal epithelial cell (IEC) antimicrobial immunity via toxin dependent and independent means and that the 'anaerobic' environment has a significant impact on bacterial-IEC interactions. Crosstalk between three C. difficile PCR ribotypes (RT) [RT027 (strain R20291), RT012 (strain 630) and RT017 (strains M68 and CF5)] and IEC cell-lines were investigated. All RTs showed significant engagement with human Toll-like receptors (TLR)-5, TLR2-CD14 and TLR2/6 as measured by IL-8 release from TLR-transfected HEK cells. Co-culture studies indicated minimal impact of R20291 and 630 TcdA and TcdB on bacterial adherence to Caco-2 cells. An apical anaerobic environment had a major effect on C. difficile-T84 crosstalk as significantly greater cytokine immunity and trans-epithelial electrical resistance (TEER) dysfunction was recorded when co-cultures were performed in an Ussing chamber system compared to standard 5% CO2 conditions. Overall, this study suggests that anaerobic C. difficile engagement with human IECs is a complex interplay that involves bacterial and toxin-mediated cellular events.
艰难梭菌感染是发达国家医疗保健相关腹泻的主要原因之一。尽管现在人们已经充分了解艰难梭菌毒素在疾病发病机制中的作用，但人类肠道上皮细胞与艰难梭菌之间宿主 - 病原体相互作用的许多方面，可能导致无症状携带和/或临床疾病，目前仍不太清楚。在此，我们测试了这样一个假设，即艰难梭菌菌株通过毒素依赖性和非依赖性方式介导肠道上皮细胞（IEC）的抗菌免疫，并且“厌氧”环境对细菌与IEC的相互作用有重大影响。研究了三种艰难梭菌PCR核糖体分型（RT）[RT027（菌株R20291）、RT012（菌株630）和RT017（菌株M68和CF5）]与IEC细胞系之间的相互作用。通过转染TLR的HEK细胞释放的IL-8测量，所有RT均显示与人类Toll样受体（TLR）-5、TLR2-CD14和TLR2/6有显著相互作用。共培养研究表明，R20291和630的TcdA和TcdB对细菌黏附于Caco-2细胞的影响最小。与标准5%二氧化碳条件相比，在尤斯灌流室系统中进行共培养时，顶端厌氧环境对艰难梭菌与T84细胞的相互作用有重大影响，因为记录到显著更强的细胞因子免疫和跨上皮电阻（TEER）功能障碍。总体而言，这项研究表明，厌氧条件下艰难梭菌与人类IEC的相互作用是一个复杂的相互作用过程，涉及细菌和毒素介导的细胞事件。
