Electronic Cigarette (E-Cigarette) Vapor Exposure Alters the Streptococcus pneumoniae Transcriptome in a Nicotine-Dependent Manner without Affecting Pneumococcal Virulence
Electronic Cigarette (E-Cigarette) Vapor Exposure Alters the Streptococcus pneumoniae Transcriptome in a Nicotine-Dependent Manner without Affecting Pneumococcal Virulence
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DOI：
10.1128/aem.02125-19
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发表时间：
2020-02-01
影响因子：
4.4
通讯作者：
Kulkarni, Ritwij
中科院分区：
文献类型：
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作者：
Bagale, Kamal;Paudel, Santosh;Kulkarni, Ritwij
电子烟蒸气 (EV) 暴露对呼吸道微生物群生理学的影响尚未完全确定。我们分析了暴露于含尼古丁和不含尼古丁电子烟液配方的蒸汽对肺炎链球菌菌株 TIGR4 的毒力和转录组的影响，TIGR4 是一种无症状定植于人类鼻咽粘膜的病原体。 TIGR4 预先暴露于含尼古丁的 EV 提取物 (EVE+NIC)、不含尼古丁的 EV 提取物 (EVE-NIC)、香烟烟雾提取物 (CSE) 或营养丰富的胰蛋白酶大豆 (TS) 肉汤（对照）中 2 小时。使用转录组测序（RNA 测序 [RNA-Seq]）、体外毒力测定和急性肺炎体内小鼠模型探索治疗菌株和对照菌株之间的差异。 RNA-Seq图谱分析显示，与对照相比，EVE-NIC预暴露的TIGR4中涉及糖转运和代谢的14个基因的表达发生了适度变化，而EVE+NIC或CSE暴露分别改变了264和982个基因的表达，其中大多数与代谢和应激反应有关。使用对照 TIGR4 或使用预先暴露于 EVE+NIC、EVE-NIC 的 TIGR4 感染急性肺炎小鼠模型。或 CSE 没有显示出疾病参数的显着差异，例如细菌器官负荷和呼吸细胞因子反应。有趣的是，暴露于 CSE 或 EVE+NIC（但不是 EVE-NIC）的 TIGR4 表现出适度的生物膜形成诱导。然而，没有一个治疗组显示出肺炎球菌疏水性或上皮细胞粘附性的显着改变。总之，我们的研究报告称，暴露于 EV 会以尼古丁依赖性方式显着改变肺炎链球菌转录组，而不影响肺炎球菌毒力。 重要性 随着电子烟在吸烟和不吸烟成人和儿童中的日益普及，以及最近与电子烟相关的肺部疾病和死亡的报道，有必要进一步分析电子烟蒸气 (EV) 暴露对健康的不利影响。由于肺炎链球菌等病原菌可以作为共生菌定植于人类鼻咽部，因此它们可能会受到接触EV中生物活性化学物质的影响。因此，在这项研究中，我们研究了 EV 暴露对肺炎链球菌菌株 TIGR4 生理学的影响。为了区分尼古丁和非尼古丁成分的影响，我们专门比较了暴露于含尼古丁和不含尼古丁电子烟液配方蒸气的 TIGR4 的 RNA 测序图谱和毒力。我们观察到，含尼古丁的 EV 增强了 TIGR4 生物膜，并改变了主要参与代谢和应激反应的 TIGR4 基因的表达。然而，含尼古丁和不含尼古丁的 EV 都不影响小鼠模型中 TIGR4 的毒力。
The effects of electronic cigarette (e-cigarette) vapor (EV) exposure on the physiology of respiratory microflora are not fully defined. We analyzed the effects of exposure to vapor from nicotine-containing and nicotine-free e-liquid formulations on the virulence and transcriptome of Streptococcus pneumoniae strain TIGR4, a pathogen that asymptomatically colonizes the human nasopharyngeal mucosa. TIGR4 was preexposed for 2 h to nicotine-containing EV extract (EVE+NIC), nicotine-free EV extract (EVE-NIC), cigarette smoke extract (CSE), or nutrient-rich tryptic soy (TS) broth (control). The differences between the treatment and control strains were explored using transcriptome sequencing (RNA sequencing [RNA-Seq]), in vitro virulence assays, and an in vivo mouse model of acute pneumonia. The analysis of RNA-Seq profiles revealed modest changes in the expression of 14 genes involved in sugar transport and metabolism in EVE-NIC-preexposed TIGR4 compared to the control, while EVE+NIC or CSE exposure altered expression of 264 and 982 genes, respectively, most of which were involved in metabolism and stress response. Infection in a mouse model of acute pneumonia with control TIGR4 or with TIGR4 preexposed to EVE+NIC, EVE-NIC. or CSE did not show significant differences in disease parameters, such as bacterial organ burden and respiratory cytokine response. Interestingly, TIGR4 exposed to CSE or EVE+NIC (but not EVE-NIC) exhibited moderate induction of biofilm formation. However, none of the treatment groups showed significant alterations in pneumococcal hydrophobicity or epithelial cell adherence. In summary, our study reports that exposure to EV significantly alters the S. pneumoniae transcriptome in a nicotine-dependent manner without affecting pneumococcal virulence.IMPORTANCE With the increasing popularity of e-cigarettes among cigarette smoking and nonsmoking adults and children and the recent reports of vaping-related lung illness and deaths, further analysis of the adverse health effects of e-cigarette vapor (EV) exposure is warranted. Since pathogenic bacteria such as Streptococcus pneumoniae can colonize the human nasopharynx as commensals, they may be affected by exposure to bioactive chemicals in EV. Hence, in this study we examined the effects of EV exposure on the physiology of S. pneumoniae strain TIGR4. In order to differentiate between the effects of nicotine and nonnicotine components, we specifically compared the RNA-Seq profiles and virulence of TIGR4 exposed to vapor from nicotine-containing and nicotine-free e-liquid formulations. We observed that nicotine-containing EV augmented TIGR4 biofilms and altered expression of TIGR4 genes predominantly involved in metabolism and stress response. However, neither nicotine-containing nor nicotine-free EV affected TIGR4 virulence in a mouse model.