Department of Chemical Engineering, Stanford University, Stanford, CA 94305.
Department of Chemistry, Stanford University, Stanford, CA 94305.
Proc Natl Acad Sci U S A. 2018 Oct 2;115(40):10106-10111. doi: 10.1073/pnas.1801564115. Epub 2018 Sep 19.
Uropathogenic (UPEC) are the major causative agents of urinary tract infections, employing numerous molecular strategies to contribute to adhesion, colonization, and persistence in the bladder niche. Identifying strategies to prevent adhesion and colonization is a promising approach to inhibit bacterial pathogenesis and to help preserve the efficacy of available antibiotics. This approach requires an improved understanding of the molecular determinants of adhesion to the bladder urothelium. We designed experiments using a custom-built live cell monolayer rheometer (LCMR) to quantitatively measure individual and combined contributions of bacterial cell surface structures [type 1 pili, curli, and phosphoethanolamine (pEtN) cellulose] to bladder cell adhesion. Using the UPEC strain UTI89, isogenic mutants, and controlled conditions for the differential production of cell surface structures, we discovered that curli can promote stronger adhesive interactions with bladder cells than type 1 pili. Moreover, the coproduction of curli and pEtN cellulose enhanced adhesion. The LCMR enables the evaluation of adhesion under high-shear conditions to reveal this role for pEtN cellulose which escaped detection using conventional tissue culture adhesion assays. Together with complementary biochemical experiments, the results support a model wherein cellulose serves a mortar-like function to promote curli association with and around the bacterial cell surface, resulting in increased bacterial adhesion strength at the bladder cell surface.
尿路致病性大肠杆菌（UPEC）是尿路感染的主要病原体，它们采用多种分子策略来促进在膀胱腔中的黏附、定植和持续存在。确定预防黏附和定植的策略是抑制细菌发病机制并有助于保持现有抗生素疗效的有前途的方法。这种方法需要更好地了解黏附到膀胱尿路上皮的分子决定因素。我们使用定制的活细胞单层流变仪（LCMR）设计实验，定量测量细菌表面结构（1 型菌毛、卷曲菌和磷酸乙醇胺（pEtN）纤维素）对膀胱细胞黏附的单独和组合贡献。使用 UPEC 菌株 UTI89、同基因突变体和控制细胞表面结构差异产生的条件，我们发现卷曲菌可以促进与膀胱细胞更强的黏附相互作用，而不是 1 型菌毛。此外，卷曲菌和 pEtN 纤维素的共生产增加了黏附。LCMR 可在高剪切条件下评估黏附，从而揭示 pEtN 纤维素的作用，这在使用传统的组织培养黏附测定时无法检测到。与互补的生化实验一起，这些结果支持了一种模型，即纤维素起到灰浆样的作用，促进卷曲菌与细菌表面的关联和围绕细菌表面的关联，从而增加了膀胱细胞表面的细菌黏附强度。
