Increased extracellular vesicle miRNA-466 family in the bronchoalveolar lavage fluid as a precipitating factor of ARDS.

BACKGROUND: Acute respiratory distress syndrome (ARDS) is a life-threatening disease; however, its treatment has not yet been fully established. The progression of ARDS is considered to be mediated by altered intercellular communication between immune and structural cells in the lung. One of several factors involved in intercellular communication is the extracellular vesicle (EV). They act as carriers of functional content such as RNA molecules, proteins, and lipids and deliver cargo from donor to recipient cells. EVs have been reported to regulate the nucleotide-binding oligomerization like receptor 3 (NLRP3) inflammasome. This has been identified as the cellular machinery responsible for activating inflammatory processes, a key component responsible for the pathogenesis of ARDS. METHODS: Here, we provide comprehensive genetic analysis of microRNAs (miRNAs) in EVs, demonstrating increased expression of the miRNA-466 family in the bronchoalveolar lavage fluid of a mouse ARDS model. RESULTS: Transfection of bone marrow-derived macrophages (BMDMs) with miRNA-466 g and 466 m-5p resulted in increased interleukin-1 beta (IL-1ß) release after LPS and ATP treatment, which is an established in vitro model of NLRP3 inflammasome activation. Moreover, LPS-induced pro-IL-1ß expression was accelerated by miRNA-466 g and 466 m-5p in BMDMs. CONCLUSIONS: These findings imply that miRNA-466 family molecules are secreted via EVs into the airways in an ARDS model, and this exacerbates inflammation through the NLRP3 inflammasome. Our results suggest that the NLRP3 inflammasome pathway, regulated by extracellular vesicle miRNA, could act as a therapeutic target for ARDS.

Relationship between Anti-SARS-CoV-2 S Abs and IFN-λ3 Levels in the Administration of Oxygen following COVID-19 Vaccination.

Although the effectiveness of vaccination at preventing hospitalization and severe coronavirus disease (COVID-19) has been reported in numerous studies, the detailed mechanism of innate immunity occurring in host cells by breakthrough infection is unclear. One hundred forty-six patients were included in this study. To determine the effects of vaccination and past infection on innate immunity following SARS-CoV-2 infection, we analyzed the relationship between anti-SARS-CoV-2 S Abs and biomarkers associated with the deterioration of COVID-19 (IFN-λ3, C-reactive protein, lactate dehydrogenase, ferritin, procalcitonin, and D-dimer). Anti-S Abs were classified into two groups according to titer: high titer (≥250 U/ml) and low titer (<250 U/ml). A negative correlation was observed between anti-SARS-CoV-2 S Abs and IFN-λ3 levels (r = -0.437, p < 0.001). A low titer of anti-SARS-CoV-2 S Abs showed a significant association with oxygen demand in patients, excluding aspiration pneumonia. Finally, in a multivariate analysis, a low titer of anti-SARS-CoV-2 S Abs was an independent risk factor for oxygen demand, even after adjusting for age, sex, body mass index, aspiration pneumonia, and IFN-λ3 levels. In summary, measuring anti-SARS-CoV-2 S Abs and IFN-λ3 may have clinical significance for patients with COVID-19. To predict the oxygen demand of patients with COVID-19 after hospitalization, it is important to evaluate the computed tomography findings to determine whether the pneumonia is the result of COVID-19 or aspiration pneumonia.

Iron-Dependent Mitochondrial Dysfunction Contributes to the Pathogenesis of Pulmonary Fibrosis.

Although the pathogenesis of pulmonary fibrosis remains unclear, it is known to involve epithelial injury and epithelial-mesenchymal transformation (EMT) as a consequence of cigarette smoke (CS) exposure. Moreover, smoking deposits iron in the mitochondria of alveolar epithelial cells. Iron overload in mitochondria causes the Fenton reaction, leading to reactive oxygen species (ROS) production, and ROS leakage from the mitochondria induces cell injury and inflammation in the lungs. Nevertheless, the mechanisms underlying iron metabolism and pulmonary fibrosis are yet to be elucidated. In this study, we aimed to determine whether iron metabolism and mitochondrial dysfunction are involved in the pathogenesis of pulmonary fibrosis. We demonstrated that administration of the iron chelator deferoxamine (DFO) reduced CS-induced pulmonary epithelial cell death, mitochondrial ROS production, and mitochondrial DNA release. Notably, CS-induced cell death was reduced by the administration of an inhibitor targeting ferroptosis, a unique iron-dependent form of non-apoptotic cell death. Transforming growth factor-ß-induced EMT of pulmonary epithelial cells was also reduced by DFO. The preservation of mitochondrial function reduced Transforming growth factor-ß-induced EMT. Furthermore, transbronchial iron chelation ameliorated bleomycin-induced pulmonary fibrosis and leukocyte migration in a murine model. Our findings indicate that iron metabolism and mitochondrial dysfunction are involved in the pathogenesis of pulmonary fibrosis. Thus, they may be leveraged as new therapeutic targets for pulmonary fibrosis.

Effective ferroptotic small-cell lung cancer cell death from SLC7A11 inhibition by sulforaphane.

Small-cell lung cancer (SCLC) is a highly aggressive cancer with poor prognosis, due to a lack of therapeutic targets. Sulforaphane (SFN) is an isothiocyanate derived from cruciferous vegetables and has shown anticancer effects against numerous types of cancer. However, its anticancer effect against SCLC remains unclear. The present study aimed to demonstrate the anticancer effects of SFN in SCLC cells by investigating cell death (ferroptosis, necroptosis and caspase inhibition). The human SCLC cell lines NCI-H69, NCI-H69AR (H69AR) and NCI-H82 and the normal bronchial epithelial cell line, 16HBE14o- were used to determine cell growth and cytotoxicity, evaluate the levels of iron and glutathione, and quantify lipid peroxidation following treatment with SFN. mRNA expression levels of cystine/glutamate antiporter xCT (SLC7A11), a key component of the cysteine/glutamate antiporter, were measured using reverse transcription-quantitative PCR, while the levels of SLC7A11 protein were measured using western blot analysis. Following the addition of SFN to the cell culture, cell growth was significantly inhibited, and cell death was shown in SCLC and multidrug-resistant H69AR cells. The ferroptotic effects of SFN were confirmed following culture with the ferroptosis inhibitor, ferrostatin-1, and deferoxamine; iron levels were elevated, which resulted in the accumulation of lipid reactive oxygen species. The mRNA and protein expression levels of SLC7A11 were significantly lower in SFN-treated cells compared with that in the control cells (P<0.0001 and P=0.0006, respectively). These results indicated that the anticancer effects of SFN may be caused by ferroptosis in the SCLC cells, which was hypothesized to be triggered from the inhibition of mRNA and protein expression levels of SLC7A11. In conclusion, the present study demonstrated that SFN-induced cell death was mediated via ferroptosis and inhibition of the mRNA and protein expression levels of SLC7A11 in SCLC cells. The anticancer effects of SFN may provide novel options for SCLC treatment.