Experimental Lung Research最新文献

Purpose: Chronic obstructive pulmonary disease (COPD) is a persistent inflammatory disorder characterized by minor airway inflammation and emphysema involving various cell types and cytokines. MicroRNAs (miRNAs) have emerged as critical regulators in the pathogenesis of lung diseases. This study investigates the impact of microRNA-24 (miR-24) on airway inflammatory responses in a rat model of COPD.

Materials and methods: The model was established by combining cigarette smoke exposure and lipopolysaccharide stimulation, and rat lung tissues were transfected with adeno-associated viruses overexpressing miR-24. Pathological changes in the lung were assessed using hematoxylin and eosin staining. Levels of pro-inflammatory cytokines, including tumor necrosis factor-alpha, interleukin-6, and interleukin-8, were measured using enzyme-linked immunosorbent assay. Expression of miR-24 and S100A8 was detected through quantitative reverse transcription PCR, while protein levels of S100A8, Toll-like receptor 4 (TLR4), and myeloid differentiation primary response 88 (MyD88) were assessed using western blotting. Bioinformatics analysis and dual-luciferase reporter assay were performed to determine the relationship between S100A8 and miR-24.

Results: The results demonstrated the downregulation of miR-24 in rats with COPD, and its overexpression resulted in a significant decrease in S1008 mRNA levels. Additionally, the protein level of S100A8 was significantly increased in the lung tissues of COPD rats. The upregulation of miR-24, however, not only inhibited the protein expression of S100A8, TLR4, and MyD88 in lung tissues but also reduced the release of pro-inflammatory cytokines in the plasma and bronchoalveolar lavage fluid, thereby attenuating inflammatory responses and pathological injuries in the lung.

Conclusions: Our data suggest that miR-24 attenuates airway inflammatory responses in COPD by inhibiting the TLR4/MyD88 pathway via targeting S100A8.

Recent advances in cystic fibrosis (CF) treatments have led to improved survival, with life expectancy for Australians living with CF at 57yo. As life expectancy improves, long-term cardiovascular disease risk factors (as for the general population) will become an issue in these patients. We hypothesized that increased leukocyte expression of vasoconstriction and pro-fibrotic mediators may contribute to CF severity in adults with CF. We recruited 13 adult and 24 pediatric healthy controls, and 53 adults and 9 children living with CF. Leukocyte expression/release of endothelin-1 (ET1) and members of the TGF-β/Smad signaling were measured by multifluorescence quantitative confocal microscopy, Western blotting, ELISA, and real-time quantitative polymerase chain reaction. The association between plasma ET1 levels and lung function was assessed. Leukocytes from adults living with CF expressed higher ET1 levels (p = 0.0033), and TGF-β (p = 0.0031); the phosphorylation ratio increased for Smad2/3 (p = 0.0136) but decreased for Smad1/5/8 (p = 0.0007), vs. control subjects. Plasma ET1 levels were significantly increased in adults with CF with FEV₁<50% (p = 0.002) vs. controls, and adults with CF with normal lung function. The release of ET1 in adult plasma inversely correlated with CF severity (-0.609, p = 0.046). Our data indicates that upregulated ET1 and TGF-β/Smad signaling in leukocytes may contribute to CF severity, highlighting the need for further investigations into their impact on the clinical outcomes of people living with CF.

Purpose: In this study, we identified differentially expressed genes (DEGs) and signaling pathways to gain insight into the pathogenesis of acute lung injury (ALI). Methods: C57BL/6 mice were intravenously injected with lipopolysaccharide (LPS) to establish a sepsis-induced ALI model. Hematoxylin-eosin (H&E) and enzyme-linked immunosorbent assays (ELISAs) were used to evaluate the model. Whole transcriptome sequencing was performed to identify the expression changes in lncRNAs, circRNAs, miRNAs and mRNAs in lung tissues. The crucial RNAs and the biological function of the target genes were confirmed and annotated based on bioinformatics analysis. Real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was employed to verify the expression levels of key lncRNAs, circRNAs, miRNAs and mRNAs in the lung tissues and human bronchoalveolar lavage (BALF). Results: A total of 3304 (1632 upregulated and 1672 downregulated) differentially expressed mRNAs, 794 (397 up and 397 down) differentially expressed lncRNAs, 89 (58 up and 31 down) differentially expressed circRNAs, and 14 (11 up and 3 down) differentially expressed miRNAs were identified between the control and LPS lung tissues. The lncRNA ceRNA subnetwork and circRNA ceRNA subnetwork were constructed based on the observed interaction and co-expression among the differentially expressed RNAs. An analysis of the protein-protein interaction (PPI) network and hub genes revealed crucial mRNAs for circRNA-Tcf20. The lncRNA-Snhg12, Edn1, Stat1, miR-212-3p and miR-223-3p were upregulated in sepsis ARDS patients. CircRNA-Tcf20, Col1a1, Col1a2 and Flt3 were significantly downregulated in sepsis ARDS patients. The biological function analysis indicated that these genes were enriched in the TNF signaling pathway, Necroptosis signaling pathway and the PI3K-Akt signaling pathway. Conclusions: Our findings suggest that circRNA-Tcf20, miR-212-3p, miR-223-3p, Col1a1, Col1a2 and Flt3 may be new regulatory factors that participate in the pathogenesis of sepsis-related acute lung injury. CircRNA-Tcf20, lncRNA-Snhg12 and all the other RNAs may be potential biomarkers for septic ALI/ARDS.

Purpose: Ischemia-reperfusion injury (IRI) is a major challenge in lung transplantation often causing graft dysfunction and chronic airway illnesses in recipients. To prevent potential transplant related complications, strict guidelines were put in place to choose viable donor lungs with minimal risk of IRI. These regulations deem most of the donor organs unfit for transplant which then are donated for research to understand the mechanisms of health and diseases in human. However, resected organs that are being transported undergo cold ischemia that can negatively affect the tissue architecture and other cellular functions under study. Thus, it is important to assess how cold ischemia time (CIT) affects the physiological mechanism. In this respect, we are interested in studying how CIT affects cellular senescence in normal aging and various pulmonary pathologies. We thus hypothesized that prolonged CIT exhibits cell-type specific changes in lung cellular senescence in mice. Methods: Lung lobes from C57BL/6J (n = 5-8) mice were harvested and stored in UW Belzer cold storage solution for 0, 4-, 9-, 12-, 24-, and 48-h CIT. Lung cellular senescence was determined using fluorescence (C₁₂FdG) assay and co-immunolabelling was performed to identify changes in individual cell types. Results: We found a rapid decline in the overall lung cellular senescence after 4-h of CIT in our study. Co-immunolabelling revealed the endothelial cells to be most affected by cold ischemia, demonstrating significant decrease in the endothelial cell senescence immediately after harvest. Annexin V-PI staining further revealed a prominent increase in the number of necrotic cells at 4-h CIT, thus suggesting that most of the cells undergo cell death within a few hours of cold ischemic injury. Conclusions: We thus concluded that CIT significantly lowers the cellular senescence in lung tissues and must be considered as a confounding factor for mechanistic studies in the future.

Background: Lung ischemia-reperfusion injury (LIRI) is among the complications observed after lung transplantation and is associated with morbidity and mortality. Preconditioning of the donor lung before organ retrieval may improve organ quality after transplantation. We investigated whether preconditioning with metformin (Met) ameliorates LIRI after lung transplantation. Methods: Twenty Lewis rats were randomly divided into the sham, LIRI, and Met groups. The rats in the LIRI and Met groups received saline and Met, respectively, via oral gavage. Subsequently, a donor lung was harvested and kept in cold storage for 8 h. The LIRI and Met groups then underwent left lung transplantation. After 2 h of reperfusion, serum and transplanted lung tissues were examined. Results: The partial pressure of oxygen (PaO₂) was greater in the Met group than in the LIRI group. In the Met group, wet-to-dry (W/D) weight ratios, inflammatory factor levels, oxidative stress levels and apoptosis levels were notably decreased. Conclusions: Met protects against ischemia-reperfusion injury after lung transplantation in rats, and its therapeutic effect is associated with its anti-inflammatory, antioxidative, and antiapoptotic properties.