Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, Louisiana, USA.
Department of Microbiology and Immunology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, Louisiana, USA
Infect Immun. 2019 Apr 23;87(5). doi: 10.1128/IAI.00832-18. Print 2019 Mar.
is an emerging human pathogen that causes pharyngitis and wound infections. A few studies have suggested that is able to induce its uptake into nonphagocytic epithelial cells, but the bacterial factors associated with host cell invasion and the host cell processes involved have yet to be studied. We investigated how two virulence factors, arcanolysin (ALN) and phospholipase D (PLD), affect the ability of the bacteria to adhere to and subsequently invade Detroit 562 pharyngeal epithelial cells. The sphingomyelinase activity of phospholipase D was necessary to increase bacterial adherence, while the absence of a functional arcanolysin had no effect on adherence but did lead to a decrease in invasion into Detroit 562 cells. Because of the known roles of cholesterol-dependent cytolysins in disrupting calcium gradients and inducing F-actin-mediated bacterial internalization, we sought to determine whether ALN and PLD played a similar role in the ability of to invade nonphagocytic cells. Elimination of extracellular calcium and inhibition of the Arp2/3 complex or F-actin polymerization also caused a decrease in the ability of to invade Detroit 562 cells. Overall, our findings suggest that utilizes phospholipase D primarily for adherence and utilizes arcanolysin primarily for invasion into Detroit 562 cells in a process dependent on extracellular calcium and F-actin polymerization. Our work marks the first insight into how the individual activities of arcanolysin and phospholipase D affect host-pathogen interactions using the biologically relevant Detroit 562 cell line.
是一种新兴的人类病原体，可引起咽炎和伤口感染。一些研究表明，能够将其摄取到非吞噬性上皮细胞中，但与宿主细胞入侵相关的细菌因素和涉及的宿主细胞过程尚未得到研究。我们研究了两种 毒力因子，arcanolysin (ALN) 和磷脂酶 D (PLD)，如何影响细菌粘附和随后入侵底特律 562 咽上皮细胞的能力。磷脂酶 D 的鞘磷脂酶活性对于增加细菌粘附是必需的，而缺乏功能性 arcanolysin 对 粘附没有影响，但确实导致 入侵底特律 562 细胞减少。由于胆固醇依赖性细胞溶素在破坏钙梯度和诱导 F-肌动蛋白介导的细菌内化方面的已知作用，我们试图确定 ALN 和 PLD 是否在 入侵非吞噬细胞的能力中发挥类似作用。消除细胞外钙并抑制 Arp2/3 复合物或 F-肌动蛋白聚合也会降低 入侵底特律 562 细胞的能力。总的来说，我们的发现表明，利用磷脂酶 D 主要用于粘附，利用 arcanolysin 主要用于入侵底特律 562 细胞，这一过程依赖于细胞外钙和 F-肌动蛋白聚合。我们的工作首次深入了解了 arcanolysin 和磷脂酶 D 的单独活性如何利用生物学相关的底特律 562 细胞系影响 宿主-病原体相互作用。
