Decreased diversity of nasal microbiota and their secreted extracellular vesicles in patients with chronic rhinosinusitis based on a metagenomic analysis.

BACKGROUND: Chronic rhinosinusitis (CRS) is an inflammatory process in the nasal cavity and paranasal sinuses, and bacteria have been considered to be a cause. Indeed, recent evidence indicates that bacteria-derived extracellular vesicles (EV) appear to be an important causative agent of inflammatory diseases. Here, we aimed to evaluate the diversity of nasal microbiota and their secreted EV in patients with CRS. METHODS: Nasal lavage (NAL) fluid samples were obtained from five patients with CRS with polyposis, three patients with CRS without polyposis, and three non-CRS controls. After preparation of bacteria and EV from samples using differential centrifugation, genomic DNA was extracted and 16S-rDNA amplicons were subjected to high-throughput pyrosequencing on a Roche 454 GS-FLX platform. RESULTS: Metagenomics showed that bacteria composition was positively correlated with EV composition. Samples from patients with CRS had greater bacterial abundance and lower diversity, both from bacteria and the EV portion of samples, compared with non-CRS samples. At each phylogenetic level, Bacteroidetes decreased while Proteobacteria increased in the CRS group at the phylum level. At the genus level, Prevotella spp. decreased in the CRS group, while Staphylococcus spp. increased from both bacteria and EV. Moreover, Staphylococcus aureus and its secreting EV compositions were higher in samples from CRS with polyps compared with CRS without polyps. CONCLUSIONS: These results suggest that patients with CRS have altered nasal microbiota and decreased diversity in bacterial compositions as well as increased S. aureus abundance in those patients with polyps.

Staphylococcus aureus-derived extracellular vesicles induce neutrophilic pulmonary inflammation via both Th1 and Th17 cell responses.

BACKGROUND: Recent evidence indicates that Staphylococcus aureus, one of the most important human pathogens, secretes vesicles into the extracellular milieu. OBJECTIVE: To evaluate whether inhalation of S. aureus-derived extracellular vesicles (EV) is causally related to the pathogenesis of inflammatory pulmonary diseases. METHODS: Staphylococcus aureus EV were prepared by sequential ultrafiltration and ultracentrifugation. The innate immune response was evaluated in vitro after the application of EV to airway epithelial cells and alveolar macrophages. In vivo innate and adaptive immune responses were evaluated after airway exposure to EV. Adjuvant effects of EV on the development of hypersensitivity to inhaled allergens were also evaluated after airway sensitization with S. aureus EV and ovalbumin (OVA). RESULTS: Staphylococcus aureus and S. aureus EV were detected in house dust. Alveolar macrophages produced both tumor necrosis α (TNF-α) and interleukin 6 (IL-6) after in vitro stimulation with S. aureus EV, whereas airway epithelial cells produced only IL-6. Repeated airway exposure to S. aureus EV induced both Th1 and Th17 cell responses and neutrophilic pulmonary inflammation, mainly via a Toll-like receptor 2 (TLR2)-dependent mechanism. In terms of adjuvant effects, airway sensitization with S. aureus EV and OVA resulted in neutrophilic pulmonary inflammation after OVA challenge alone. This phenotype was partly reversed by the absence of interferon γ (IFN-γ) or IL-17. CONCLUSION: Staphylococcus aureus EV can induce Th1 and Th17 neutrophilic pulmonary inflammation, mainly in a TLR2-dependent manner. Additionally, S. aureus EV enhance the development of airway hypersensitivity to inhaled allergens.

PARP1 enhances lung adenocarcinoma metastasis by novel mechanisms independent of DNA repair.

The role of poly (ADP-ribose) polymerase 1 (PARP1) in cancer has been extensively studied in the context of DNA repair, leading to clinical trials of PARP1 inhibitors in cancers defective in homologous recombination. However, the DNA repair-independent roles of PARP1 in carcinogenesis and metastasis, particularly in lung cancer metastasis, remain largely uncharacterized. Here, we report that PARP1 promotes lung adenocarcinoma relapse to the brain and bones by regulating several steps of the metastatic process in a DNA repair-independent manner. We find that PARP1 expression is associated with overall and distant metastasis-free survival in lung adenocarcinoma patients. Consistent with this, genetic knockdown and pharmacological inhibition of PARP1 significantly attenuated the metastatic potential of lung adenocarcinoma cells. Further investigation revealed that PARP1 potentiates lung adenocarcinoma metastasis by promoting invasion, anoikis resistance, extravasation and self-renewal of lung adenocarcinoma cells and also by modifying the brain microenvironment. Finally, we identified S100A4 and CLDN7 as novel transcriptional targets and clinically relevant effectors of PARP1. Collectively, our study not only revealed previously unknown functions of PARP1 in lung adenocarcinoma metastasis but also delineated the molecular mechanisms underlying the pro-metastatic function of PARP1. Furthermore, these findings provide a foundation for the potential use of PARP1 inhibitors as a new treatment option for lung adenocarcinoma patients with elevated PARP1 expression.