Bacterial outer membrane vesicle (OMV)-mediated delivery of proteins to host cells is an important mechanism of host-pathogen communication. Emerging evidence suggests that OMVs contain differentially packaged short RNAs (sRNAs) with the potential to target host mRNA function and/or stability. In this study, we used RNA-Seq to characterize differentially packaged sRNAs in Pseudomonas aeruginosa OMVs, and to show transfer of OMV sRNAs to human airway cells. We selected one sRNA for further study based on its stable secondary structure and predicted mRNA targets. Our candidate sRNA (sRNA52320), a fragment of a P. aeruginosa methionine tRNA, was abundant in OMVs and reduced LPS-induced as well as OMV-induced IL-8 secretion by cultured primary human airway epithelial cells. We also showed that sRNA52320 attenuated OMV-induced KC cytokine secretion and neutrophil infiltration in mouse lung. Collectively, these findings are consistent with the hypothesis that sRNA52320 in OMVs is a novel mechanism of host-pathogen interaction whereby P. aeruginosa reduces the host immune response.

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogen chronically infecting the lungs of patients with chronic obstructive pulmonary disease (COPD), pneumonia, cystic fibrosis (CF), and bronchiectasis. Cif (PA2934), a bacterial toxin secreted in outer membrane vesicles (OMV) by P. aeruginosa, reduces CFTR-mediated chloride secretion by human airway epithelial cells, a key driving force for mucociliary clearance. The aim of this study was to investigate the mechanism whereby Cif reduces CFTR-mediated chloride secretion. Cif redirected endocytosed CFTR from recycling endosomes to lysosomes by stabilizing an inhibitory effect of G3BP1 on the deubiquitinating enzyme (DUB), USP10, thereby reducing USP10-mediated deubiquitination of CFTR and increasing the degradation of CFTR in lysosomes. This is the first example of a bacterial toxin that regulates the activity of a host DUB. These data suggest that the ability of P. aeruginosa to chronically infect the lungs of patients with COPD, pneumonia, CF, and bronchiectasis is due in part to the secretion of OMV containing Cif, which inhibits CFTR-mediated chloride secretion and thereby reduces the mucociliary clearance of pathogens.

Calcium mediates various neuronal functions. The complexity of neuronal

The phenotype of cone dystrophy with supernormal rod response is tightly linked with mutations in KCNV2.

Cystic fibrosis (CF), the most common lethal genetic disease in Caucasians, is characterized by chronic bacterial lung infection and excessive inflammation, which lead to progressive loss of lung function and premature death. Although ivacaftor (VX-770) alone and ivacaftor in combination with lumacaftor (VX-809) improve lung function in CF patients with the Gly551Asp and del508Phe mutations, respectively, the effects of these drugs on the function of human CF macrophages are unknown. Thus studies were conducted to examine the effects of lumacaftor alone and lumacaftor in combination with ivacaftor (i.e., ORKAMBI) on the ability of human CF ( del508Phe/ del508Phe) monocyte-derived macrophages (MDMs) to phagocytose and kill Pseudomonas aeruginosa. Lumacaftor alone restored the ability of CF MDMs to phagocytose and kill P. aeruginosa to levels observed in MDMs obtained from non-CF (WT-CFTR) donors. This effect contrasts with the partial (~15%) correction of del508Phe Cl secretion of airway epithelial cells by lumacaftor. Ivacaftor reduced the ability of lumacaftor to stimulate phagocytosis and killing of P. aeruginosa. Lumacaftor had no effect on P. aeruginosa-stimulated cytokine secretion by CF MDMs. Ivacaftor (5 µM) alone and ivacaftor in combination with lumacaftor reduced secretion of several proinflammatory cytokines. The clinical efficacy of ORKAMBI may be related in part to the ability of lumacaftor to stimulate phagocytosis and killing of P. aeruginosa by macrophages.