A Comparative Analysis of Edwardsiella tarda-Induced Transcriptome Profiles in RAW264.7 Cells Reveals New Insights into the Strategy of Bacterial Immune Evasion

Abstract

Edwardsiella tarda is a Gram-negative bacterial pathogen with a broad host range, including fish, reptiles, and mammals. One prominent virulence feature of E. tarda is its ability to survive and replicate in host phagocytes, but the relevant molecular mechanism is largely unknown. In this study, we examined the transcriptome profiles of RAW264.7 cells, a murine macrophage cell line, infected with live E. tarda or stimulated with dead E. tarda for 4 h and 8 h. Eighteen libraries were constructed, and an average of 69 million clean reads per library were obtained, with ~81.63% of the reads being successfully mapped to the reference genome. In total, 208 and 232 differentially expressed genes (DEGs) were identified between live and dead E. tarda-treated cells at 4 h and 8 h post-infection, respectively. The DEGs were markedly enriched in the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways associated with immunity. Live E. tarda differed strikingly from dead E. tarda in the regulation of immune related genes. Compared with dead E. tarda-treated cells, live E. tarda-treated cells exhibited marked and significant suppression in the induction of a large amount of immune genes, including RIG-I-like receptors, cytokines, and interferon-related genes. Furthermore, some of the immune genes highly regulated by live E. tarda formed complicated interaction networks with each other. Together, the results of this study revealed a transcriptome profile specifically induced by the active virulence elements of live E. tarda during the infection process, thus adding new insights into the intracellular infection mechanism of E. tarda. This study also provided a valuable set of target genes for further study of the immune evasion strategy of E. tarda.

Pediatric Acute Lymphoblastic Leukemia Patients Exhibit Distinctive Alterations in the Gut Microbiota

“…By analyzing differential bacterial species between ALL and NC groups, we found that the relative abundance of Edwardsiella tarda and Prevotella maculosa were reduced among the childhood ALL patients and positively correlated with the level of interleukin-10 (IL-10). Edwardsiella (Li et al, 2019 ) and Prevotella (Kostic et al, 2013 ) were both reported to be involved in immune functions. Their correlations with IL-10 is of particular interest, since several polymorphisms and splicing variants of IL-10 gene has been identified as predictive biomarkers for ALL (Wu et al, 2005 ; Lo et al, 2016 ; Ghufran et al, 2019 ).…”

In vitro Edwardsiella piscicida CK108 Transcriptome Profiles with Subinhibitory Concentrations of Phenol and Formalin Reveal New Insights into Bacterial Pathogenesis Mechanisms

“…In order to validate the RNA-seq results, the expression levels of DEGs were further evaluated by qRT-PCR. The expression level of gapdh (ETAC_06975), which is widely used in E. tarda as an internal control gene [ 30 ], was independent from the sub-ICs of phenol and formalin ( Tables S1 and S2 ). Candidate genes ( baeR , hisA , hcp , eseC and fliC ) for the validation were chosen from DEGs involved in two-component systems, histidine biosynthesis and motility and secretion systems that displayed increased or decreased transcription levels in response to chemicals ( Figure 5 , Tables S1 and S2 ).…”

Transcriptome Analysis Reveals Possible Immunomodulatory Activity Mechanism of Chlorella sp. Exopolysaccharides on RAW264.7 Macrophages

“…DEGs were further analyzed by GO enrichment and KEGG pathway enrichment [ 67 ]. DEGs were mapped to the GO database ( , accessed on 25 February 2021) for GO enrichment analysis using Goatools software, while the pathway enrichment analysis was carried out using Kyoto Encyclopedia of Genes and Genomes ( , accessed on 25 February 2021).…”