sirolimus and Cystic-Fibrosis

Topics: Adaptor Proteins, Signal Transducing; Anti-Bacterial Agents; Autophagy; Azithromycin; Case-Control Studies; Chemokine CCL4; Chloroquine; Cystic Fibrosis; Gene Expression Regulation; Host-Pathogen Interactions; Humans; Immunosuppressive Agents; Interleukin-8; Mycobacterium abscessus; Neutrophils; Phagocytosis; Primary Cell Culture; Reactive Oxygen Species; Signal Transduction; Sirolimus; Wortmannin

Pulmonary antibiotic delivery is recommended as maintenance therapy for cystic fibrosis (CF) patients who experience chronic infections. However, abnormally thick and sticky mucus present in the respiratory tract of CF patients impairs mucus penetration and limits the efficacy of inhaled antibiotics. To overcome the obstacles of pulmonary antibiotic delivery, we have developed nanocomposite microparticles (nCmP) for the inhalation application of antibiotics in the form of dry powder aerosols.. Azithromycin-loaded and rapamycin-loaded polymeric nanoparticles (NP) were prepared via nanoprecipitation and nCmP were prepared by spray drying and the physicochemical characteristics were evaluated.. The nanoparticles were 200 nm in diameter both before loading into and after redispersion from nCmP. The NP exhibited smooth, spherical morphology and the nCmP were corrugated spheres about 1 μm in diameter. Both drugs were successfully encapsulated into the NP and were released in a sustained manner. The NP were successfully loaded into nCmP with favorable encapsulation efficacy. All materials were stable at manufacturing and storage conditions and nCmP were in an amorphous state after spray drying. nCmP demonstrated desirable aerosol dispersion characteristics, allowing them to deposit into the deep lung regions for effective drug delivery.. The described nCmP have the potential to overcome mucus-limited pulmonary delivery of antibiotics.

Topics: Azithromycin; Cystic Fibrosis; Drug Delivery Systems; Humans; Nanocomposites; Nanoparticles; Particle Size; Respiratory Tract Infections; Sirolimus; Treatment Outcome; X-Ray Diffraction

A 27-year-old female patient was referred to our outpatient clinic with a 1-year history of shortness of breath when walking fast on level ground or when climbing stairs. Symptoms worsened after a second episode of spontaneous left pneumothorax, when a chest tube was placed in another hospital for complete lung expansion. During this hospitalization, an open lung biopsy was performed. There was no history of rhinorrhea, nasal congestion, cough, hemoptysis, wheezing, or expectoration.

Topics: Adult; Antibiotics, Antineoplastic; Cystic Fibrosis; Diagnosis, Differential; Disease Management; Female; Humans; Lung; Lung Neoplasms; Lymphangioleiomyomatosis; Multiple Pulmonary Nodules; Sirolimus; Tuberous Sclerosis

Azithromycin is a potent macrolide antibiotic with poorly understood antiinflammatory properties. Long-term use of azithromycin in patients with chronic inflammatory lung diseases, such as cystic fibrosis (CF), results in improved outcomes. Paradoxically, a recent study reported that azithromycin use in patients with CF is associated with increased infection with nontuberculous mycobacteria (NTM). Here, we confirm that long-term azithromycin use by adults with CF is associated with the development of infection with NTM, particularly the multi-drug-resistant species Mycobacterium abscessus, and identify an underlying mechanism. We found that in primary human macrophages, concentrations of azithromycin achieved during therapeutic dosing blocked autophagosome clearance by preventing lysosomal acidification, thereby impairing autophagic and phagosomal degradation. As a consequence, azithromycin treatment inhibited intracellular killing of mycobacteria within macrophages and resulted in chronic infection with NTM in mice. Our findings emphasize the essential role for autophagy in the host response to infection with NTM, reveal why chronic use of azithromycin may predispose to mycobacterial disease, and highlight the dangers of inadvertent pharmacological blockade of autophagy in patients at risk of infection with drug-resistant pathogens.

Topics: Adult; Animals; Anti-Bacterial Agents; Autophagy; Azithromycin; Chlorocebus aethiops; COS Cells; Cystic Fibrosis; Drug Resistance, Bacterial; Enzyme Inhibitors; HeLa Cells; Humans; Lysosomes; Macrolides; Macrophages; Mice; Mice, Inbred C57BL; Microtubule-Associated Proteins; Mycobacterium; Mycobacterium Infections; Phagosomes; Recombinant Fusion Proteins; Sirolimus

Topics: Animals; Autophagy; Burkholderia cenocepacia; Burkholderia Infections; Cystic Fibrosis; Pneumonia; Sirolimus

Cystic fibrosis (CF) is the most common inherited lethal disease of Caucasians which results in multi organ dysfunction. However, 85% of the deaths are due to pulmonary infections. Infection by Burkholderia cenocepacia (B. cepacia) is a particularly lethal threat to CF patients because it causes severe and persistent lung inflammation and is resistant to nearly all available antibiotics. In CFTR ΔF508 mouse macrophages, B. cepacia persists in vacuoles that do not fuse with the lysosomes and mediates increased production of IL-1β. It is believed that intracellular bacterial survival contributes to the persistence of the bacterium. Here we show for the first time that in wild-type macrophages but not in ΔF508 macrophages, many B. cepacia reside in autophagosomes that fuse with lysosomes at later stages of infection. Accordingly, association and intracellular survival of B. cepacia are higher in CFTR-ΔF508 (ΔF508) macrophages than in WT macrophages. An autophagosome is a compartment that engulfs non-functional organelles and parts of the cytoplasm then delivers them to the lysosome for degradation to produce nutrients during periods of starvation or stress. Furthermore, we show that B. cepacia downregulates autophagy genes in WT and ΔF508 macrophages. However, autophagy dysfunction is more pronounced in ΔF508 macrophages since they already have compromised autophagy activity. We demonstrate that the autophagy-stimulating agent, rapamycin markedly decreases B. cepacia infection in vitro by enhancing the clearance of B. cepacia via induced autophagy. In vivo, Rapamycin decreases bacterial burden in the lungs of CF mice and drastically reduces signs of lung inflammation. Together, our studies reveal that if efficiently activated, autophagy can control B. cepacia infection and ameliorate the associated inflammation. Therefore, autophagy is a novel target for new drug development for CF patients to control B. cepacia infection and accompanying inflammation.

Topics: Animals; Autophagy; Burkholderia cenocepacia; Burkholderia Infections; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Disease Models, Animal; Down-Regulation; Interleukin-1beta; Intracellular Space; Lysosomes; Macrophages; Mice; Mice, Inbred C57BL; Microbial Viability; Microtubule-Associated Proteins; Mutation; Phagosomes; Pneumonia; RNA, Small Interfering; Sirolimus; Vacuoles