Transcytosis subversion by M cell-to-enterocyte spread promotes Shigella flexneri and Listeria monocytogenes intracellular bacterial dissemination.
Camille ReyYuen-Yan ChangPatricia Latour-LambertHugo VaretCaroline ProuxRachel LegendreJean-Yves CoppéeJost EnningaPublished in: PLoS pathogens (2020)
Microfold (M) cell host-pathogen interaction studies would benefit from the visual analysis of dynamic cellular and microbial interplays. We adapted a human in vitro M cell model to physiological bacterial infections, expression of fluorescent localization reporters and long-term three-dimensional time-lapse microscopy. This approach allows following key steps of M cell infection dynamics at subcellular resolution, from the apical onset to basolateral epithelial dissemination. We focused on the intracellular pathogen Shigella flexneri, classically reported to transcytose through M cells to initiate bacillary dysentery in humans, while eliciting poorly protective immune responses. Our workflow was critical to reveal that S. flexneri develops a bimodal lifestyle within M cells leading to rapid transcytosis or delayed vacuolar rupture, followed by direct actin motility-based propagation to neighboring enterocytes. Moreover, we show that Listeria monocytogenes, another intracellular pathogen sharing a tropism for M cells, disseminates in a similar manner and evades M cell transcytosis completely. We established that actin-based M cell-to-enterocyte spread is the major dissemination pathway for both pathogens and avoids their exposure to basolateral compartments in our system. Our results challenge the notion that intracellular pathogens are readily transcytosed by M cells to inductive immune compartments in vivo, providing a potential mechanism for their ability to evade adaptive immunity.
Keyphrases
- single cell
- induced apoptosis
- cell therapy
- cell cycle arrest
- immune response
- blood brain barrier
- listeria monocytogenes
- metabolic syndrome
- poor prognosis
- stem cells
- oxidative stress
- high throughput
- cardiovascular disease
- endothelial cells
- bone marrow
- quantum dots
- physical activity
- climate change
- social media
- signaling pathway
- mass spectrometry
- candida albicans
- staphylococcus aureus
- dendritic cells
- cell death
- risk assessment