The Departments of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA.
The Departments of Biochemistry, UT Southwestern Medical Center, Dallas, TX, USA.
Cell Commun Signal. 2024 Jun 21;22(1):341. doi: 10.1186/s12964-024-01609-7.
Pseudomonas aeruginosa (PA) is an opportunistic pathogen that can cause sight threatening infections in the eye and fatal infections in the cystic fibrosis airway. Extracellular vesicles (EVs) are released by host cells during infection and by the bacteria themselves; however, there are no studies on the composition and functional role of host-derived EVs during PA infection of the eye or lung. Here we investigated the composition and capacity of EVs released by PA infected epithelial cells to modulate innate immune responses in host cells.
Human telomerase immortalized corneal epithelial cells (hTCEpi) cells and human telomerase immortalized bronchial epithelial cells (HBECs) were treated with a standard invasive test strain of Pseudomonas aeruginosa, PAO1, for 6 h. Host derived EVs were isolated by qEV size exclusion chromatography. EV proteomic profiles during infection were compared using mass spectrometry and functional studies were carried out using hTCEpi cells, HBECs, differentiated neutrophil-like HL-60 cells, and primary human neutrophils isolated from peripheral blood.
EVs released from PA infected corneal epithelial cells increased pro-inflammatory cytokine production in naïve corneal epithelial cells and induced neutrophil chemotaxis independent of cytokine production. The EVs released from PA infected bronchial epithelial cells were also chemotactic although they failed to induce cytokine secretion from naïve HBECs. At the proteomic level, EVs derived from PA infected corneal epithelial cells exhibited lower complexity compared to bronchial epithelial cells, with the latter having reduced protein expression compared to the non-infected control.
This is the first study to comprehensively profile EVs released by corneal and bronchial epithelial cells during Pseudomonas infection. Together, these findings show that EVs released by PA infected corneal and bronchial epithelial cells function as potent mediators of neutrophil migration, contributing to the exuberant neutrophil response that occurs during infection in these tissues.
铜绿假单胞菌（PA）是一种机会性病原体，可导致眼部视力威胁性感染和囊性纤维化气道致命感染。细胞外囊泡（EVs）是宿主细胞在感染过程中和细菌自身释放的；然而，目前还没有关于 PA 感染眼部或肺部时宿主来源 EVs 的组成和功能作用的研究。在这里，我们研究了 PA 感染上皮细胞释放的 EVs 的组成和功能，以调节宿主细胞的固有免疫反应。
用人端粒酶永生化角膜上皮细胞（hTCEpi）和人端粒酶永生化支气管上皮细胞（HBEC）用标准侵袭性测试菌株铜绿假单胞菌 PAO1 处理 6 小时。通过 qEV 大小排除色谱法分离宿主来源的 EVs。使用质谱比较感染过程中 EV 的蛋白质组谱，并使用 hTCEpi 细胞、HBECs、分化的中性粒细胞样 HL-60 细胞和从外周血分离的原代人中性粒细胞进行功能研究。
PA 感染角膜上皮细胞释放的 EVs 增加了未感染角膜上皮细胞中促炎细胞因子的产生，并诱导中性粒细胞趋化，而不依赖细胞因子的产生。PA 感染支气管上皮细胞释放的 EVs 也具有趋化性，但它们不能诱导未感染的 HBECs 分泌细胞因子。在蛋白质组水平上，PA 感染角膜上皮细胞衍生的 EVs 与支气管上皮细胞相比表现出较低的复杂性，后者的蛋白质表达与未感染对照相比降低。
这是第一项全面分析 PA 感染角膜和支气管上皮细胞释放的 EVs 的研究。这些发现表明，PA 感染的角膜和支气管上皮细胞释放的 EVs 作为中性粒细胞迁移的有效介质，有助于这些组织中感染时发生的过度中性粒细胞反应。
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