Heterologous expression of Streptococcus mutans Cnm in Lactococcus lactis promotes intracellular invasion, adhesion to human cardiac tissues and virulence
Heterologous expression of Streptococcus mutans Cnm in Lactococcus lactis promotes intracellular invasion, adhesion to human cardiac tissues and virulence
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DOI：
10.1080/21505594.2016.1195538
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发表时间：
2017-01-01
期刊：
影响因子：
5.2
通讯作者：
Abranches, Jacqueline
中科院分区：
文献类型：
--
作者：
Freires, Irlan A.;Aviles-Reyes, Alejandro;Abranches, Jacqueline
In S.在大蜡螟无脊椎动物模型中，表面糖蛋白Cnm的表达介导与细胞外基质蛋白的结合、内皮细胞侵袭和毒力。为了进一步研究Cnm作为一种毒力因子的特性，我们从S.使用乳链菌肽诱导系统在非致病性乳酸乳球菌NZ9800中表达变异菌株OMZ175。尽管缺乏Cnm糖基化所必需的机制，但Western印迹和免疫荧光显微镜分析表明，Cnm有效表达并易位到L.乳酸。类似于S。变形链球菌中Cnm的表达。乳酸菌能与胶原和层粘连蛋白结合，并能侵入人冠状动脉内皮细胞，增加G.梅隆内拉使用离体人心脏组织定殖模型，我们表明，Cnm阳性菌株的S。变形链球菌或L.乳酸菌在组织定殖方面胜过它们的Cnm阴性对应物。最后，Cnm的表达促进了L.兔感染性心内膜炎模型中乳酸菌粘附和定植。总的来说，我们的研究结果提供了明确的证据表明，结合细胞外基质介导的Cnm是一个重要的毒力属性的S。并证实了L.乳酸菌异源系统，用于进一步表征细菌毒力因子。
In S. mutans, the expression of the surface glycoprotein Cnm mediates binding to extracellular matrix proteins, endothelial cell invasion and virulence in the Galleria mellonella invertebrate model. To further characterize Cnm as a virulence factor, the cnm gene from S. mutans strain OMZ175 was expressed in the non-pathogenic Lactococcus lactis NZ9800 using a nisin-inducible system. Despite the absence of the machinery necessary for Cnm glycosylation, Western blot and immunofluorescence microscopy analyses demonstrated that Cnm was effectively expressed and translocated to the cell wall of L. lactis. Similar to S. mutans, expression of Cnm in L. lactis enabled robust binding to collagen and laminin, invasion of human coronary artery endothelial cells and increased virulence in G. mellonella. Using an ex vivo human heart tissue colonization model, we showed that Cnm-positive strains of either S. mutans or L. lactis outcompete their Cnm-negative counterparts for tissue colonization. Finally, Cnm expression facilitated L. lactis adhesion and colonization in a rabbit model of infective endocarditis. Collectively, our results provide unequivocal evidence that binding to extracellular matrices mediated by Cnm is an important virulence attribute of S. mutans and confirm the usefulness of the L. lactis heterologous system for further characterization of bacterial virulence factors.