Pseudomonas aeruginosa N-3-Oxo-Dodecanoyl-Homoserine Lactone Impacts Mitochondrial Networks Morphology, Energetics, and Proteome in Host Cells

Abstract

Mitochondria play crucial roles in cellular metabolism, signaling, longevity, and immune defense. Recent evidences have revealed that the host microbiota, including bacterial pathogens, impact mitochondrial behaviors and activities in the host. The pathogenicity of Pseudomonas aeruginosa requires quorum sensing (QS) cell-cell communication allowing the bacteria to sense population density and collectively control biofilm development, virulence traits, adaptation and interactions with the host. QS molecules, like N-3-oxo-dodecanoyl-L-homoserine lactone (3O-C 12-HSL), can also modulate the behavior of host cells, e.g., epithelial barrier properties and innate immune responses. Here, in two types of cells, fibroblasts and intestinal epithelial cells, we investigated whether and how P. aeruginosa 3O-C 12-HSL impacts the morphology of mitochondrial networks and their energetic characteristics, using high-resolution transmission electron microscopy, fluorescence live-cell imaging, assay for mitochondrial bioenergetics, and quantitative mass spectrometry for mitoproteomics and bioinformatics. We found that 3O-C 12-HSL induced fragmentation of mitochondria, disruption of cristae and inner membrane ultrastructure, altered major characteristics of respiration and energetics, and decreased mitochondrial membrane potential, and that there are distinct cell-type specific details of these effects. Moreover, this was mechanistically accompanied by differential expression of both common and cell-type specific arrays of components in the mitochondrial proteome involved in their structural organization, electron transport chain complexes and response to stress. We suggest that this effect of 3O-C 12-HSL on mitochondria may represent one of the events in the interaction between P. aeruginosa and host mitochondria and may have an impact on the pathogens strategy to hijack host cell activities to support their own survival and spreading.

An Organ System-Based Synopsis ofPseudomonas aeruginosaVirulence

“…Similarly, oxo-C 12 -HSL stimulates phagocytic activity of human macrophages by inducing the p38 MAPK, which causes positive changes in cell volume, morphology, and water channel AQP9 that promotes phagocytosis [ 114 ]. In contrast, oxo-C 12 -HSL, but not C 4 -HSL, induces apoptosis in phagocytic cells [ 115 ], interferes with proper functioning of mitochondria [ 116 ], and alters the expression and secretion of multiple pro- and anti-inflammatory cytokines and chemokines [ 117 , 118 ]. However, these results need to be interpreted with caution because the vast majority of host modulation studies were performed in vitro using oxo-C 12 -HSL in concentrations between 300 and 600 μM, often in different immortalized cell lines.…”

Impact of N-Acyl-Homoserine Lactones, Quorum Sensing Molecules, on Gut Immunity

“…AHL have cell-type-specific impacts, but overall, the effects tend to be anti-inflammatory. Besides, 3-oxo-C12-HSL effects on apoptosis are dependent on the cell types, as multiple studies do not report toxicity on differentiated epithelial cells or fibroblasts ( 31 , 55 , 56 ). The effects of 3-oxo-C12-HSL on immune cells are compiled in the Table S1 .…”

Effect of Quorum Sensing Inducers and Inhibitors on Cytoplasmic Incompatibility Induced byWolbachia(Rickettsiales: Anaplasmataceae) in American Serpentine Leafminer (Diptera: Agromyzidae): Potential Tool for the Incompatible Insect Technique

“…3O-C12-HSL was reported to induce QS during Gram-negative bacteria infection ( Smith et al 2002 ), thereby affecting the host ( Josephson et al 2020 ). Dermal injection of 1–10 µM 3O-C12-HSL in mice induced QS in P. aeruginosa , leading to lung inflammation ( Smith et al 2002 ); and 50 µM 3O-C12-HSL modulated QS in bacteria, which impacted host mitochondria ( Josephson et al 2020 ). As QS is related to bacterial density and Wolbachia density influences CI level, QS may be indirectly associated with CI level.…”

“…The QS inducers N-(3-oxododecanoyl) homoserine lactone (3O-C12-HSL) and N-acetyl- l -homoserine lactone (C2HSL) (both from Tocris, Minneapolis, MN) and spermidine (Cayman Chemical, Ann Arbor, MI) and QS inhibitors 4-phenylbutanoyl (4-phenyl) (Combi-Blocks, Sandiego, CA) and 4-nitro-pyridine-N-oxide (4-NPO) (Tokyo chemical industry, Tokyo, Japan) were used at the following concentrations: 3O-C12-HSL: 1, 10, and 100 µM ( Smith et al 2002 , Josephson et al 2020 ), C2HSL: 0.1, 1, and 10 µM ( Smith et al 2002 ; Liu et al 2019 ); spermidine, 1, 10, and 100 µM ( Nasrallah et al 2011 ); 4-phenyl, 50, 100, and 150 µM ( Schaefer et al 1996 ); and 4-NPO: 10 and 100 µM, and 1 mM ( Rasmussen et al 2005 ). Unmated L. trifolii adults were collected within 24 h after emergence and were fed the chemical in honey (honey put in 1x1 cm cotton) in a 6.5 cm (width) × 6.5 cm (length) × 9.5 cm (height) cage, for one day.…”