Centre of Microbial and Plant Genetics, K.U. Leuven, Leuven, Belgium.
Appl Environ Microbiol. 2012 Jan;78(1):185-93. doi: 10.1128/AEM.06192-11. Epub 2011 Oct 21.
Lactobacillus rhamnosus GG, a probiotic with good survival capacity in the human gut, has well-documented adhesion properties and health effects. Recently, spaCBA-encoded pili that bind to human intestinal mucus were identified on its cell surface. Here, we report on the phenotypic analysis of a spaCBA pilus knockout mutant in comparison with the wild type and other adhesin mutants. The SpaCBA pilus of L. rhamnosus GG showed to be key for efficient adherence to the Caco-2 intestinal epithelial cell (IEC) line and biofilm formation. Moreover, the spaCBA mutant induces an elevated level of interleukin-8 (IL-8) mRNA in Caco-2 cells compared to the wild type, possibly involving an interaction of lipoteichoic acid with Toll-like receptor 2. In contrast, an L. rhamnosus GG mutant without exopolysaccharides but with an increased exposure of pili leads to the reduced expression of IL-8. Using Transwells to partition bacteria from Caco-2 cells, IL-8 induction is blocked completely regardless of whether wild-type or mutant L. rhamnosus GG cells are used. Taken together, our data suggest that L. rhamnosus GG SpaCBA pili, while promoting strong adhesive interactions with IECs, have a functional role in balancing IL-8 mRNA expression induced by surface molecules such as lipoteichoic acid.
鼠李糖乳杆菌 GG 是一种在人类肠道中具有良好生存能力的益生菌，具有良好的黏附特性和健康效应。最近，在其细胞表面鉴定出了 SpaCBA 编码的与人类肠道黏液结合的菌毛。在此，我们报告了 spaCBA 菌毛敲除突变体与野生型和其他黏附突变体的表型分析。鼠李糖乳杆菌 GG 的 SpaCBA 菌毛对于与 Caco-2 肠上皮细胞 (IEC) 系和生物膜形成的有效黏附至关重要。此外，与野生型相比，spaCBA 突变体在 Caco-2 细胞中诱导白细胞介素 8 (IL-8) mRNA 的水平升高，这可能涉及脂磷壁酸与 Toll 样受体 2 的相互作用。相比之下，缺乏胞外多糖但菌毛暴露增加的鼠李糖乳杆菌 GG 突变体导致 IL-8 的表达减少。使用 Transwell 将细菌与 Caco-2 细胞分开，无论使用野生型还是突变型鼠李糖乳杆菌 GG 细胞，IL-8 的诱导都会被完全阻断。综上所述，我们的数据表明，鼠李糖乳杆菌 GG SpaCBA 菌毛在与 IEC 形成强烈黏附相互作用的同时，在平衡脂磷壁酸等表面分子诱导的 IL-8 mRNA 表达方面具有功能作用。
