Robinson Jonathan L, Brynildsen Mark P
Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA.
Bioengineering (Basel). 2016 Feb 6;3(1):9. doi: 10.3390/bioengineering3010009.
Enterohemorrhagic (EHEC) are responsible for large outbreaks of hemorrhagic colitis, which can progress to life-threatening hemolytic uremic syndrome (HUS) due to the release of Shiga-like toxins (Stx). The presence of a functional nitric oxide (NO·) reductase (NorV), which protects EHEC from NO· produced by immune cells, was previously found to correlate with high HUS incidence, and it was shown that NorV activity enabled prolonged EHEC survival and increased Stx production within macrophages. To enable quantitative study of EHEC NO· defenses and facilitate the development of NO·-potentiating therapeutics, we translated an existing kinetic model of the K-12 NO· response to an EHEC O157:H7 strain. To do this, we trained uncertain model parameters on measurements of [NO·] and [O₂] in EHEC cultures, assessed parametric and prediction uncertainty with the use of a Markov chain Monte Carlo approach, and confirmed the predictive accuracy of the model with experimental data from genetic mutants lacking NorV or Hmp (NO· dioxygenase). Collectively, these results establish a methodology for the translation of quantitative models of NO· stress in model organisms to pathogenic sub-species, which is a critical step toward the application of these models for the study of infectious disease.
肠出血性大肠杆菌（EHEC）会引发大规模的出血性结肠炎疫情，由于志贺样毒素（Stx）的释放，这种疾病可能会发展为危及生命的溶血尿毒综合征（HUS）。此前发现，功能性一氧化氮（NO·）还原酶（NorV）的存在可保护EHEC免受免疫细胞产生的NO·的侵害，且其与高HUS发病率相关，还表明NorV活性可使EHEC在巨噬细胞内长期存活并增加Stx的产生。为了能够对EHEC的NO·防御进行定量研究，并促进NO·增强疗法的开发，我们将现有的K - 12对NO·反应的动力学模型转化为EHEC O157:H7菌株的模型。为此，我们根据EHEC培养物中[NO·]和[O₂]的测量值对不确定的模型参数进行训练，使用马尔可夫链蒙特卡罗方法评估参数和预测的不确定性，并用来自缺乏NorV或Hmp（NO·双加氧酶）的基因变体的实验数据确认了模型的预测准确性。总体而言，这些结果建立了一种将模式生物中NO·应激的定量模型转化为致病亚种模型的方法，这是将这些模型应用于传染病研究的关键一步。
