A compensatory RNase E variation increases Iron Piracy and Virulence in multidrug-resistant Pseudomonas aeruginosa during Macrophage infection

Abstract

During chronic cystic fibrosis (CF) infections, evolved Pseudomonas aeruginosa antibiotic resistance is linked to increased pulmonary exacerbations, decreased lung function, and hospitalizations. However, the virulence mechanisms underlying worse outcomes caused by antibiotic resistant infections are poorly understood. Here, we investigated evolved aztreonam resistant P. aeruginosa virulence mechanisms. Using a macrophage infection model combined with genomic and transcriptomic analyses, we show that a compensatory mutation in the rne gene, encoding RNase E, increased pyoverdine and pyochelin siderophore gene expression, causing macrophage ferroptosis and lysis. We show that iron-bound pyochelin was sufficient to cause macrophage ferroptosis and lysis, however, apo-pyochelin, iron-bound pyoverdine, or apo-pyoverdine were insufficient to kill macrophages. Macrophage killing could be eliminated by treatment with the iron mimetic gallium. RNase E variants were abundant in clinical isolates, and CF sputum gene expression data show that clinical isolates phenocopied RNase E variant functions during macrophage infection. Together these data show how P. aeruginosa RNase E variants can cause host damage via increased siderophore production and host cell ferroptosis but may also be targets for gallium precision therapy.

A deep insight into ferroptosis in lung disease: facts and perspectives

“…Also, it has been shown that PA decreases the effects of host GPx4 to induce lipid peroxidation by activating lysosomal chaperone-mediated autophagy ( 160 ). Using a macrophage infection model, P. aeruginosa RNase E variants cause host infection damage by increasing host cell siderophore production and iron cell apoptosis ( 161 ). In summary, PA is closely related to ferroptosis, while 15LOX-induced ferroptosis progression serves as a therapeutic target, providing new therapeutic ideas for non-antibiotic treatment of PA-induced airway infections.…”