Membrane Vesicles of <i>Enterococcus faecalis</i>: In Vitro Composition Analysis and Macrophage Inflammatory Response Under Different pH Conditions

<i>Enterococcus faecalis</i> (<i>E. faecalis</i>) is one of the most detected bacteria in persistent apical periodontitis (PAP), with alkaline tolerance enabling post-treatment survival. In this study, we will investigate how alkaline conditions alter proteomic and metabolomi...

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Main Authors: Zijian Yuan, Wenling Huang, Poukei Chan, Jiani Zhou, Jingheng Liang, Lihong Guo
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Microorganisms
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Online Access:https://www.mdpi.com/2076-2607/13/6/1344
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author Zijian Yuan
Wenling Huang
Poukei Chan
Jiani Zhou
Jingheng Liang
Lihong Guo
author_facet Zijian Yuan
Wenling Huang
Poukei Chan
Jiani Zhou
Jingheng Liang
Lihong Guo
author_sort Zijian Yuan
collection DOAJ
description <i>Enterococcus faecalis</i> (<i>E. faecalis</i>) is one of the most detected bacteria in persistent apical periodontitis (PAP), with alkaline tolerance enabling post-treatment survival. In this study, we will investigate how alkaline conditions alter proteomic and metabolomic profiles of <i>E. faecalis</i> membrane vesicles (MVs) and preliminarily investigate the role of MVs of <i>E. faecalis</i> in the regulation of macrophage inflammatory response. <i>E. faecalis</i> MVs were characterized using transmission electron microscopy and nanoparticle tracking analysis under varying pH conditions. MVs’ proteomic and metabolomic profiling across pH levels was compared. The effects of <i>E. faecalis</i> MVs on human dTHP-1 macrophages were evaluated using CCK-8 metabolic activity assays and ELISA-based quantitative analysis of inflammatory cytokines. In this study, the presence of <i>E. faecalis</i> MVs was verified, and the alkaline environment of pH 9.0 did not alter their production. Through proteomic and metabolomic analysis, we observed that ATP synthase and stress proteins, as well as lysine degradation and tryptophan metabolism pathways, were significantly enriched in the MVs at pH 9.0. Finally, we observed that both <i>E. faecalis</i> MVs at pH 7.0 and pH 9.0 could dose-dependently inhibit the activity of dTHP-1 cells. <i>E. faecalis</i> MVs promote the secretion of IL-6, TNF-α, IL-1β, IL-1ra, and TGF-β by macrophages. Compared to pH 7.0, pH 9.0 <i>E. faecalis</i> MVs have a reduced effect on IL-1ra and TGF-β secretion. Additionally, we observed a significant increase in the IL-1β/IL-1ra ratio after treatment with <i>E. faecalis</i> MVs. Our study indicated that <i>E. faecalis</i> can produce MVs in pH 7.0 and pH 9.0 environments. ATP synthase, stress proteins, as well as lysine degradation and tryptophan metabolism pathways, were significantly enriched in pH 9.0 MVs. Furthermore, <i>E. faecalis</i> MVs could promote inflammatory responses in macrophages and dose-dependently inhibit the viability of dTHP-1 cells.
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spelling doaj-art-293df72bee9a4eafbbbe39a2c13e71082025-08-20T03:16:21ZengMDPI AGMicroorganisms2076-26072025-06-01136134410.3390/microorganisms13061344Membrane Vesicles of <i>Enterococcus faecalis</i>: In Vitro Composition Analysis and Macrophage Inflammatory Response Under Different pH ConditionsZijian Yuan0Wenling Huang1Poukei Chan2Jiani Zhou3Jingheng Liang4Lihong Guo5Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou 510055, ChinaHospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou 510055, ChinaHospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou 510055, ChinaHospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou 510055, ChinaHospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou 510055, ChinaHospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou 510055, China<i>Enterococcus faecalis</i> (<i>E. faecalis</i>) is one of the most detected bacteria in persistent apical periodontitis (PAP), with alkaline tolerance enabling post-treatment survival. In this study, we will investigate how alkaline conditions alter proteomic and metabolomic profiles of <i>E. faecalis</i> membrane vesicles (MVs) and preliminarily investigate the role of MVs of <i>E. faecalis</i> in the regulation of macrophage inflammatory response. <i>E. faecalis</i> MVs were characterized using transmission electron microscopy and nanoparticle tracking analysis under varying pH conditions. MVs’ proteomic and metabolomic profiling across pH levels was compared. The effects of <i>E. faecalis</i> MVs on human dTHP-1 macrophages were evaluated using CCK-8 metabolic activity assays and ELISA-based quantitative analysis of inflammatory cytokines. In this study, the presence of <i>E. faecalis</i> MVs was verified, and the alkaline environment of pH 9.0 did not alter their production. Through proteomic and metabolomic analysis, we observed that ATP synthase and stress proteins, as well as lysine degradation and tryptophan metabolism pathways, were significantly enriched in the MVs at pH 9.0. Finally, we observed that both <i>E. faecalis</i> MVs at pH 7.0 and pH 9.0 could dose-dependently inhibit the activity of dTHP-1 cells. <i>E. faecalis</i> MVs promote the secretion of IL-6, TNF-α, IL-1β, IL-1ra, and TGF-β by macrophages. Compared to pH 7.0, pH 9.0 <i>E. faecalis</i> MVs have a reduced effect on IL-1ra and TGF-β secretion. Additionally, we observed a significant increase in the IL-1β/IL-1ra ratio after treatment with <i>E. faecalis</i> MVs. Our study indicated that <i>E. faecalis</i> can produce MVs in pH 7.0 and pH 9.0 environments. ATP synthase, stress proteins, as well as lysine degradation and tryptophan metabolism pathways, were significantly enriched in pH 9.0 MVs. Furthermore, <i>E. faecalis</i> MVs could promote inflammatory responses in macrophages and dose-dependently inhibit the viability of dTHP-1 cells.https://www.mdpi.com/2076-2607/13/6/1344<i>Enterococcus faecalis</i>membrane vesiclesproteomicsmetabolomicsmacrophagesimmuno-inflammatory responses
spellingShingle Zijian Yuan
Wenling Huang
Poukei Chan
Jiani Zhou
Jingheng Liang
Lihong Guo
Membrane Vesicles of <i>Enterococcus faecalis</i>: In Vitro Composition Analysis and Macrophage Inflammatory Response Under Different pH Conditions
Microorganisms
<i>Enterococcus faecalis</i>
membrane vesicles
proteomics
metabolomics
macrophages
immuno-inflammatory responses
title Membrane Vesicles of <i>Enterococcus faecalis</i>: In Vitro Composition Analysis and Macrophage Inflammatory Response Under Different pH Conditions
title_full Membrane Vesicles of <i>Enterococcus faecalis</i>: In Vitro Composition Analysis and Macrophage Inflammatory Response Under Different pH Conditions
title_fullStr Membrane Vesicles of <i>Enterococcus faecalis</i>: In Vitro Composition Analysis and Macrophage Inflammatory Response Under Different pH Conditions
title_full_unstemmed Membrane Vesicles of <i>Enterococcus faecalis</i>: In Vitro Composition Analysis and Macrophage Inflammatory Response Under Different pH Conditions
title_short Membrane Vesicles of <i>Enterococcus faecalis</i>: In Vitro Composition Analysis and Macrophage Inflammatory Response Under Different pH Conditions
title_sort membrane vesicles of i enterococcus faecalis i in vitro composition analysis and macrophage inflammatory response under different ph conditions
topic <i>Enterococcus faecalis</i>
membrane vesicles
proteomics
metabolomics
macrophages
immuno-inflammatory responses
url https://www.mdpi.com/2076-2607/13/6/1344
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