KU Leuven, Centre of Microbial and Plant Genetics, Leuven, Belgium.
University of Antwerp, Department of Bioscience Engineering, Antwerp, Belgium.
Sci Rep. 2016 Nov 21;6:37437. doi: 10.1038/srep37437.
The probiotic Lactobacillus rhamnosus GR-1 has been documented to survive implantation onto the vaginal epithelium and interfere with urogenital pathogens. However, the molecular mechanisms involved are largely unknown. Here, we report for the first time the construction of dedicated knock-out mutants in L. rhamnosus GR-1 to enable the study of gene functions. In a search for genes responsible for the adherence capacity of L. rhamnosus GR-1, a genomic region encoding a protein with homology to lectin-like proteins was identified. Phenotypic analyses of the knock-out mutant of L. rhamnosus GR-1 revealed a two-fold decreased adhesion to the vaginal and ectocervical epithelial cell lines compared to wild-type. In contrast, the adhesion to gastro-intestinal epithelial (Caco2) and endocervical cell lines (Hela and End1/E6E7) was not drastically affected by the mutation, suggesting that the LGR-1_Llp1 lectins mediates tissue tropism. The purified LGR-1_Llp1 protein also inhibited biofilm formation and adhesion of uropathogenic Escherichia coli. For the first time, an important role for a novel lectin-like protein in the adhesion capacity and host cell-specific interaction of a vaginal probiotic Lactobacillus strain has been discovered, with an additional role in pathogen inhibition.
已证实益生菌鼠李糖乳杆菌 GR-1 能够定植于阴道上皮并干扰泌尿生殖道病原体。然而，其涉及的分子机制在很大程度上尚不清楚。本研究首次构建了鼠李糖乳杆菌 GR-1 的专用敲除突变体，以研究基因功能。在寻找与鼠李糖乳杆菌 GR-1 黏附能力相关的基因过程中，我们鉴定到一个编码具有凝集素样蛋白同源性蛋白的基因组区域。与野生型相比，鼠李糖乳杆菌 GR-1 敲除突变体的黏附能力降低了两倍。相比之下，突变对胃肠道上皮（Caco2）和宫颈内细胞系（Hela 和 End1/E6E7）的黏附没有明显影响，表明 LGR-1_Llp1 凝集素介导组织嗜性。纯化的 LGR-1_Llp1 蛋白还抑制了尿路致病性大肠杆菌的生物膜形成和黏附。本研究首次发现了一种新型凝集素样蛋白在阴道益生菌乳杆菌菌株黏附能力和宿主细胞特异性相互作用中的重要作用，同时具有抑制病原体的额外作用。
