AUTHOR=Gong Shuang , Zeng Ruixia , Liu Ling , Wang Rui , Xue Man , Dong Hao , Wu Zhigang , Zhang Yibo TITLE=Extracellular vesicles from a novel Lactiplantibacillus plantarum strain suppress inflammation and promote M2 macrophage polarization JOURNAL=Frontiers in Immunology VOLUME=Volume 15 - 2024 YEAR=2024 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2024.1459213 DOI=10.3389/fimmu.2024.1459213 ISSN=1664-3224 ABSTRACT=Background:Lactiplantibacillus plantarum (L. plantarum) is known for its probiotic properties, including antioxidant and anti-inflammatory effects. Recent studies have highlighted the role of extracellular vesicles (EVs) from prokaryotic cells in anti-inflammatory effects. Objective:This study aims to investigate the anti-inflammatory effects of extracellular vesicles derived from a newly isolated strain of L. plantarum (LP25 strain) and their role in macrophage polarization. Methods:The LP25 strain was isolated and identified through de novo sequencing, and its complete genome sequence was deposited in NCBI (GeneBank accession number: JAZHGE000000000). RAW 264.7 cells were treated with lipopolysaccharide (LPS) and/or LP25-derived extracellular vesicles (LEV). Morphological changes in the cells were observed, and the expression levels of pro-inflammatory cytokines (TNF-α, IL-6)、iNOS and anti-inflammatory cytokines (IL-10) 、Arg-1 were measured using quantitative real-time PCR (qPCR). Flow cytometry was used to detect the expression of Arg-1 in the treated cells. Results:Treatment with LP25 EVs led to significant morphological changes in RAW 264.7 cells exposed to LPS. LP25 EVs treatment resulted in increased expression of Arg-1 and anti-inflammatory cytokines IL-10, and decreased expression of iNOS and surface markers protein CD86. Flow cytometry confirmed the increased expression of the M2 macrophage marker Arg-1 in the LP25 EVs-treated group. Conclusion:Extracellular vesicles from Lactiplantibacillus plantarum LP25 can suppress inflammatory responses and promote the polarization of macrophages towards the anti-inflammatory M2 phenotype. These findings provide new evidence supporting the anti-inflammatory activity of L. plantarum-derived EVs.