NF-κB-Dependent Transcriptional Regulation of Piezo1 Mediates Bacterial Clearance on Infected Lung Stiffness
Erica M Orsini, Adam M Boulton, Susamma Abraham, Alyson Brown, Haley Ricci, Akash Ahuja, Bishnu Pant, Caitlin M Snyder, Amanda Reinhardt, Amy H Attaway, Ryan Musich, Lisa M Grove, Mitchell A Olman, Vidula Vachharajani, Rachel G ScheragaAbstract
Rationale
Respiratory pathogens, such as Pseudomonas aeruginosa damage the alveolar-capillary barrier leading to lung injury and stiffness. Lung stiffness is a key macrophage signal for bacterial clearance, but it remains unknown how stiffness-sensing mechanosensitive ion channels in macrophages are regulated during pneumonia. Macrophage Piezo1 is critical to bacterial clearance in experimental pneumonia in vivo; however, identification of putative matrix-derived signals and the mechanism of their effects remain to be determined.
Objectives
We investigated the role of P. aeruginosa virulence factors on Piezo1 activity in macrophages on infected lung matrix stiffness.
Methods
Using bone-marrow derived macrophages, we measured Piezo1 abundance and function and bacterial clearance in response to P. aeruginosa virulence factors on pathophysiologic range lung stiffnesses and standard tissue culture conditions.
Measurements and Main Results
To our knowledge, our work is the first to show that during pneumonia, transcription of the mechanosensitive ion channel Piezo1 is increased in macrophages by the NF-κB transcription factor, p65, through its signaling adaptor protein, MyD88, leading to increased Piezo1 Ca2 + channel activity. Piezo1 mRNA abundance is increased in association with open chromatin at the Piezo1 promoter in macrophages. The enhanced level of Piezo1 increases the abundance of transcription factor EB (Tfeb) resulting in lysosome biogenesis and stiffness-dependent phagolysosome maturation, a critical step for macrophage bacterial clearance.
Conclusions
Our data support the mechanism whereby transcription of macrophage Piezo1 is enhanced by p65 to augment bacterial clearance on an injured, stiffened lung matrix during pneumonia. Therefore, Piezo1 is a future therapeutic target against pneumonia-induced lung injury.