Transcriptome responses of intestinal epithelial cells induced by membrane vesicles ofListeria monocytogenesunveil novel insights into the host-pathogen cross talk

Abstract

32Membrane vesicles (MVs) serve as a vital source of virulence factors in many pathogenic organisms. The 33 release of MVs by Listeria monocytogenes is only recently recognized, but its role in the pathogenesis is 34 poorly understood. Here, we investigated the role of MVs of L. monocytogenes in virulence and host 35interactions. Proteomic analyses of whole cells and MVs of L. monocytogenes were performed using 36 LC/MS/MS. A total of 1376 and 456 proteins were identified in the L. monocytogenes cells and MVs, 37 respectively. Also, we have found that MVs contains active pore-forming listeriolysin (LLO), internalin 38 B (inlB), phosphatidylinositol-specific phospholipase C (PI-PLC-A). We have previously reported that 39MVs of L. monocytogenes can infect and induce cytotoxicity in Caco-2 cells. In this study, we report the 40 transcriptome response of Caco-2 cells upon infection with MVs as well as L. monocytogenes. In 41 particular, we observed the up-regulation of autophagy-related genes in the early phase of infection with 42 MVs. Transcription of inflammatory cytokines (CCL2, CXCL6, CXCL8, CXCL15, CXCL5, CXCL10) 43 peaked at four h of infection. A large number of differentially expressed genes was associated with actin 44 cytoskeleton rearrangement, autophagy, cell cycle arrest, and induction of oxidative stress. At a later time 45 point, transcriptional programs generated upon infection with MVs point toward to evade innate immune 46 signals, by modulating the expression of anti-inflammatory genes. KEGG pathway enrichment analysis 47 revealed that MVs induce several signaling pathways such as PI3k-Akt signaling pathway, mitogen-48 activated protein kinase (MAPK) pathway, NOD-like receptor signaling pathway, cAMP signaling 49 pathway, TNF, and NF-kB signaling pathway. Moreover, MVs induced the expression of cell cycle 50 regulatory genes, which may result in the ability to prolong host cell survival, thus protecting the 51 replicative niche for L. monocytogenes. Notably, we identified several non-coding RNAs (ncRNAs) are 52 regulated during infection, suggesting that an early manipulation of the host gene expression may be 53 essential for L. monocytogenes persistence and replication in host cells. 54 55 56 57 58 59 60 61 62 63 64 Introduction 65Several Gram-negative and Gram-positive bacteria release membrane vesicles (MVs). MVs are a 66 spherical structure of 50-300 nm in diameter composed of the single membrane that is derived from the 67 outer membrane (OM) and contains OM proteins, lipopolysaccharide (LPS), and other lipids, while the 68 vesicle lumen mainly contains periplasmic proteins (1). Many pathogenic Gram-negative bacteria species 69 extend their virulence potential by releasing spherical buds, derived from the outer membrane, so-called 70 outer membrane vesicles (2). The release of MVs can benefit the microbe, mediating microbial 71 interactions with the human host and within bacterial communities (3,2). Also, MV production protects 72 bacteria under stressful conditions by eliminating the accumu...

Biofilm formation and extracellular microvesicles—The way of foodborne pathogens toward resistance

“…Proteomics analysis of L. monocytogenes MVs was performed by Karthikeyan et al. [131]. This group could demonstrate that MVs that were secreted by this food pathogen are internalized by the host cells using actin‐mediated endocytosis.…”