Cysteamine re-establishes the clearance of Pseudomonas aeruginosa by macrophages bearing the cystic fibrosis-relevant F508del-CFTR mutation

Abstract

Cystic fibrosis (CF), the most common lethal monogenic disease in Caucasians, is characterized by recurrent bacterial infections and colonization, mainly by Pseudomonas aeruginosa, resulting in unresolved airway inflammation. CF is caused by mutations in the gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein, which functions as a chloride channel in epithelial cells, macrophages, and other cell types. Impaired bacterial handling by macrophages is a feature of CF airways, although it is still debated how defective CFTR impairs bacterial killing. Recent evidence indicates that a defective autophagy in CF macrophages leads to alterations of bacterial clearance upon infection. Here we use bone marrow-derived macrophages from transgenic mice to provide the genetic proof that defective CFTR compromises both uptake and clearance of internalized Pseudomonas aeruginosa. We demonstrate that the proteostasis regulator cysteamine, which rescues the function of the most common F508del-CFTR mutant and hence reduces lung inflammation in CF patients, can also repair the defects of CF macrophages, thus restoring both bacterial internalization and clearance through a process that involves upregulation of the pro-autophagic protein Beclin 1 and re-establishment of the autophagic pathway. Altogether these results indicate that cysteamine restores the function of several distinct cell types, including that of macrophages, which might contribute to its beneficial effects on CF.

Transglutaminase type 2 plays a key role in the pathogenesis of Mycobacterium tuberculosis infection

“…To further assess the significance of pharmacological inhibition of TG2 in macrophages, pMM0s from wt and TG2 −/− mice were infected and then treated with cystamine, another TG2 inhibitor that has already been used in preclinical studies to treat TG2‐related diseases . A similar reduction in intracellular bacterial load was observed in pMM0s treated with cystamine and Z‐DON and isolated from wt but not TG2 −/− mice (Fig.…”

“…The electron microscopy and flow cytometric analyses highlighted the presence of both apoptotic and necrotic cell death modalities upon MTB infection; a higher prevalence of the latter form of cell death was observed in TG2 wt macrophages (data not shown). To further assess the significance of pharmacological inhibition of TG2 in macrophages, pMM0s from wt and TG2 À/À mice were infected and then treated with cystamine, another TG2 inhibitor that has already been used in preclinical studies to treat TG2-related diseases [38]. A similar reduction in intracellular bacterial load was observed in pMM0s treated with cystamine and Z-DON and isolated from wt but not TG2 À/À mice (Fig.…”

Inflammation in cystic fibrosis: An update

“…Bone marrow‐derived macrophages from F508del/F508del transgenic mice had difficulty internalizing and clearing P aeruginosa . When macrophages were treated with cysteamine, a proteostasis regulator that rescues F508del function, there was reduced pro‐inflammatory mediator (TNF‐α and IL‐1β) production and improved uptake and clearance of P aeruginosa . Alveolar macrophages and MDMs from people with CF and healthy volunteers were studied ex vivo .…”

“…When macrophages were treated with cysteamine, a proteostasis regulator that rescues F508del function, there was reduced pro-inflammatory mediator (TNF-α and IL-1β) production and improved uptake and clearance of P aeruginosa. 96 Alveolar macrophages and MDMs from people with CF and healthy volunteers were studied ex vivo. 97 CF macrophages were unable to clear B cenocepacia due to defective autophagy.…”

A pathogenic role for cystic fibrosis transmembrane conductance regulator in celiac disease

“…CF is best known for its respiratory phenotype, yet also frequently leads to intestinal problems, as CFTR protein is strongly expressed all along the intestine (Gadsby et al, 2006;Ooi & Durie, 2016). CFTR is not only an anion channel, but also orchestrates proteostasis at respiratory and intestinal epithelial surfaces, meaning that it regulates adaptation to cellautonomous or environmental stress signals (Luciani et al, 2010b;Villella et al, 2013a,b;Ferrari et al, 2017). CFTR malfunction generates epithelial stress, early TG2 activation, inhibition of autophagy, and activation of innate immunity (Maiuri et al, 2008;Luciani et al, 2009;Luciani et al, 2010b;Villella et al, 2013a,b;Ferrari et al, 2017), features that are reminiscent of those triggered by gliadin in intestinal epithelial cells and celiac duodenal mucosa (Maiuri et al, 2003;Meresse et al, 2009;Barone et al, 2014).…”