Journal Article

P. aeruginosa type III and type VI secretion systems modulate early response gene expression in type II pneumocytes in vitro

Damron, F. Heath, Barbier, Mariette, Sen-Kilic, Emel, Huckaby, Annalisa B.

2022

Overview

Background Lung airway epithelial cells are part of innate immunity and the frontline of defense against bacterial infections. During infection, airway epithelial cells secrete proinflammatory mediators that participate in the recruitment of immune cells. Virulence factors expressed by bacterial pathogens can alter epithelial cell gene expression and modulate this response. Pseudomonas aeruginosa, a Gram-negative opportunistic pathogen, expresses numerous virulence factors to facilitate establishment of infection and evade the host immune response. This study focused on identifying the role of two major P. aeruginosa virulence factors, type III (T3SS) and type VI (T6SS) secretion systems, on the early transcriptome response of airway epithelial cells in vitro. Results We performed RNA-seq analysis of the transcriptome response of type II pneumocytes during infection with P. aeruginosa in vitro. We observed that P. aeruginosa differentially upregulates immediate-early response genes and transcription factors that induce proinflammatory responses in type II pneumocytes. P. aeruginosa infection of type II pneumocytes was characterized by up-regulation of proinflammatory networks, including MAPK, TNF, and IL-17 signaling pathways. We also identified early response genes and proinflammatory signaling pathways whose expression change in response to infection with P. aeruginosa T3SS and T6SS mutants in type II pneumocytes. We determined that T3SS and T6SS modulate the expression of EGR1 , FOS , and numerous genes that are involved in proinflammatory responses in epithelial cells during infection. T3SS and T6SS were associated with two distinct transcriptomic signatures related to the activation of transcription factors such as AP1, STAT1, and SP1, and the secretion of pro-inflammatory cytokines such as IL-6 and IL-8. Conclusions Taken together, transcriptomic analysis of epithelial cells indicates that the expression of immediate-early response genes quickly changes upon infection with P. aeruginosa and this response varies depending on bacterial viability and injectosomes. These data shed light on how P. aeruginosa modulates host epithelial transcriptome response during infection using T3SS and T6SS.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Activator protein 1 / Alveolar Epithelial Cells - metabolism / Analysis / Animal Genetics and Genomics / Bacteria / Bacterial diseases / Bacterial infections / Bacterial Proteins - genetics / Bacterial Proteins - metabolism / Biomedical and Life Sciences / Care and treatment / Cystic fibrosis / Cytokines / Diagnosis / Early response genes / EGR-1 protein / Epithelial cells / Epithelium / Gene Expression / Gene Expression Regulation, Bacterial / Genes / Genetic engineering / Genomics / Immune response / Immune system / Infections / Inflammation / Innate immunity / Interleukin 17 / Interleukin 6 / Interleukin 8 / Life Sciences / Lung diseases / MAP kinase / Microarrays / Microbial Genetics and Genomics / Opportunist infection / P. aeruginosa / Pathogens / Plant Genetics and Genomics / Pneumocytes / Prevention / Proteins / Proteomics / Pseudomonas aeruginosa / Pseudomonas aeruginosa - genetics / Respiratory tract / Risk factors / RNA sequencing / Signal transduction / Signaling / Sp1 protein / Stat1 protein / Transcription activation / Transcription factors / Transcription Factors - metabolism / Transcriptomes / Transcriptomics / Tumor necrosis factor / Type III secretion system / Type III Secretion Systems - genetics / Type VI secretion system / Type VI Secretion Systems - genetics / Virulence / Virulence (Microbiology) / Virulence factors / Virulence Factors - genetics