Miri Saba, Mottawea Walid, Leao Luana, Chiba Mariem, Li Yingxi, Minic Zoran, Hammami Riadh
NuGut Research Platform, School of Nutrition Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, K1N 6N5, Canada.
Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt.
Probiotics Antimicrob Proteins. 2024 Dec 16. doi: 10.1007/s12602-024-10423-z.
Bacterial intra-kingdom communication involves the secretion of outer membrane vesicles as signaling carriers to the target cells. However, limited research exists on extracellular vesicles (EVs) from Gram-positive gut bacteria, their interactions with enteric pathogens, and potential inhibitory effects. In this study, we characterized the structure, protein content, and inhibitory effects of EVs from three new potential probiotic gut symbionts, Ligilactobacillus salivarius UO.C109, Ligilactobacillus saerimneri UO.C121, and Ligilactobacillus salivarius UO.C249. EVs were isolated and characterized using three different methods (ultracentrifugation, density gradient purification, and size exclusion chromatography). The purity, dose-dependency, structure, and proteome profiles of the purified EVs were evaluated. Antibacterial and anti-virulence activities of EV subpopulations were assessed against Salmonella enterica serovar Typhimurium and Campylobacter jejuni. EVs from Lg. salivarius UO.C109 and Lg. saerimneri UO.C121 showed inhibitory activity against S. Typhimurium, whereas EVs from Lg. salivarius UO.C249 inhibited the growth of C. jejuni. Notably, purified F3 fraction exhibited the highest inhibitory activity and was enriched in lysin motif (LysM)-containing proteins, peptidoglycan hydrolases, peptidoglycan recognition proteins (PGRPs), and metallopeptidases, which have been shown to play a prominent role in antimicrobial activities against pathogens. F3 had the highest concentration (73.8%) in the 80-90 nm size compared to the other fractions. Gene expression analysis revealed that EVs from Lg. salivarius UO.C109 and Lg. saerimneri UO.C121 downregulated adhesion and invasion factors in S. Typhimurium. Likewise, EVs from Lg. salivarius UO.C249 reduced pathogenicity gene expression in C. jejuni. This study highlighted the potential of gut bacterial EVs as therapeutic agents against enteric pathogens.
细菌界内通讯涉及向外膜囊泡作为信号载体分泌至靶细胞。然而，关于革兰氏阳性肠道细菌的细胞外囊泡（EVs）、它们与肠道病原体的相互作用以及潜在抑制作用的研究有限。在本研究中，我们对来自三种新型潜在益生菌肠道共生菌唾液乳杆菌UO.C109、唾液乳杆菌UO.C121和唾液乳杆菌UO.C249的EVs的结构、蛋白质含量和抑制作用进行了表征。使用三种不同方法（超速离心、密度梯度纯化和尺寸排阻色谱）分离并表征了EVs。评估了纯化后EVs的纯度、剂量依赖性、结构和蛋白质组图谱。评估了EV亚群对鼠伤寒沙门氏菌和空肠弯曲菌的抗菌和抗毒力活性。来自唾液乳杆菌UO.C109和唾液乳杆菌UO.C121的EVs对鼠伤寒沙门氏菌显示出抑制活性，而来自唾液乳杆菌UO.C249的EVs抑制空肠弯曲菌的生长。值得注意的是，纯化后的F3组分表现出最高的抑制活性，并且富含含溶素基序（LysM）的蛋白质、肽聚糖水解酶、肽聚糖识别蛋白（PGRPs）和金属肽酶，这些已被证明在针对病原体的抗菌活性中发挥重要作用。与其他组分相比，F3在80 - 90nm尺寸中的浓度最高（73.8%）。基因表达分析表明，来自唾液乳杆菌UO.C109和唾液乳杆菌UO.C121的EVs下调了鼠伤寒沙门氏菌中的粘附和侵袭因子。同样，来自唾液乳杆菌UO.C249的EVs降低了空肠弯曲菌中致病基因的表达。本研究强调了肠道细菌EVs作为抗肠道病原体治疗剂的潜力。
