Experimental Lung Research最新文献

Background and Aim: The SplashGuard CG (SG) is a barrier enclosure developed to protect healthcare workers from SARS-CoV-2 transmission during aerosol-generating procedures. Our objective was to evaluate the protection provided by the SG against aerosolized particles (AP), using a pediatric simulation model of spontaneous ventilation (SV) and noninvasive ventilation (NIV). Methods: An aerosol generator was connected to the airways of a pediatric high-fidelity manikin with a breathing simulator. AP concentrations were measured both in SV and NIV in the following conditions: with and without SG, inside and outside the SG, with and without suction applied to the device. Results: In the SV simulated setting, AP peaks were lower with SG: 0.1 × 10⁵ particles/L compared to without: 1.6 × 10⁵, only when the ports were closed and suction applied. In the NIV simulated setting, AP peaks outside the SG were lower than without SG (20.5 × 10⁵ particles/L), whatever the situation, without suction (14.4 × 10⁵particles/L), with suction and ports open or closed: 10.3 and 0.7 × 10⁵ particles/L. In SV and NIV simulated settings, the AP peaks measured within the SG were much higher than the AP peaks measured without SG, even when suction was applied to the device. Conclusions: The SG seems to decrease peak AP exposure in the 2 ventilation contexts, but only with closed port and suction in SV. However, high concentrations of AP remain inside even with suction and SG should be used cautiously.

Background: Blast lung injury (BLI) is the most common fatal blast injury induced by overpressure wave in the events of terrorist attack, gas and underground explosion. Our previous work revealed the characteristics of inflammationrelated key proteins involved in BLI, including those regulating inflammatory response, leukocyte transendothelial migration, phagocytosis, and immune process. However, the molecular characteristics of oxidative-related proteins in BLI ar still lacking. Methods: In this study, protein expression profiling of the blast lungs obtained by tandem mass tag (TMT) spectrometry quantitative proteomics were re-analyzed to identify the characteristics of oxidative-related key proteins. Forty-eight male C57BL/6 mice were randomly divided into six groups: control, 12 h, 24 h, 48 h, 72 h and 1 w after blast exposure. The differential protein expression was identified by bioinformatics analysis and verified by western blotting. Results: The results demonstrated that thoracic blast exposure induced reactive oxygen species generation and lipid peroxidation in the lungs. Analysis of global proteins and oxidative-related proteomes showed that 62, 59, 73, 69, 27 proteins (accounted for 204 distinct proteins) were identified to be associated with oxidative stress at 12 h, 24 h, 48 h, 72 h, and 1 week after blast exposure, respectively. These 204 distinct proteins were mainly enriched in response to oxidative stress, oxidation-reduction process and lipid metabolic process. We also validated these results by western blotting. Conclusions: These findings provided new perspectives on blast-induced oxidative injury in lung, which may potentially benefit the development of future treatment of BLI.

Purpose of the study: During the early and progressive (late) stages of murine experimental pulmonary tuberculosis, the differential activation of macrophages contributes to disease development by controlling bacterial growth and immune regulation. Mycobacterial proteins P27 and PE_PGRS33 can target the mitochondria of macrophages. This study aims to evaluate the effect of both proteins on macrophage activation during mycobacterial infection. Materials and methods: We assess both proteins for mitochondrial oxygen consumption, and morphological changes, as well as bactericide activity, production of metabolites, cytokines, and activation markers in infected MQs. The cell line MH-S was used for all the experiments. Results: We show that P27 and PE_PGRS33 proteins modified mitochondrial dynamics, oxygen consumption, bacilli growth, cytokine production, and some genes that contribute to macrophage alternative activation and mycobacterial intracellular survival. Conclusions: Our findings showed that these bacterial proteins partially contribute to promoting M2 differentiation by altering mitochondrial metabolic activity.

Aim of the study: Sialidases, also called neuraminidases, are enzymes that cleave terminal sialic acids from glycoconjugates. In humans and mice, lung fibrosis is associated with desialylation of glycoconjugates and upregulation of sialidases. There are four mammalian sialidases, and it is unclear when the four mammalian sialidases are elevated over the course of inflammatory and fibrotic responses, whether tissue resident and inflammatory cells express different sialidases, and if sialidases are differentially expressed in male and females. Materials and Methods: To determine the time course of sialidase expression and the identity of sialidase expressing cells, we used the bleomycin model of pulmonary fibrosis in mice to examine levels of sialidases during inflammation (days 3 - 10) and fibrosis (days 10 - 21). Results: Bleomycin aspiration increased sialidase NEU1 at days 14 and 21 in male mice and day 10 in female mice. NEU2 levels increased at day 7 in male and day 10 in female mice. NEU3 appears to have a biphasic response in male mice with increased levels at day 7 and then at days 14 and 21, whereas in female mice NEU3 levels increased over 21 days. In control mice, the sialidases were mainly expressed by EpCAM positive epithelial cells, but after bleomycin, epithelial cells, CD45 positive immune cells, and alveolar cells expressed NEU1, NEU2, and NEU3. Sialidase expression was higher in male compared to female mice. There was little expression of NEU4 in murine lung tissue. Conclusions: These results suggest that sialidases are dynamically expressed following bleomycin, that sialidases are differentially expressed in male and females, and that of the four sialidases only NEU3 upregulation is associated with fibrosis in both male and female mice.

Aim of study: This research study aims to compare between two different counseling approaches; traditional verbal counseling vs. advanced counseling (in which we used the acoustic Flo-tone training device and its smartphone application combined with traditional verbal counseling) to determine the most beneficial counseling approach for asthmatic children who use metered-dose inhaler (MDI) with spacers concerning inhalation duration and inhalation technique mistakes. Methods: A total of 100 asthmatic children (8-18) years old were randomized into two groups (a control group, and an advanced group). Each group included 50 subjects. Every subject received 3 counseling meetings, one each month. Asthmatic children in the control group were trained on inhalation technique from MDI + spacer verbally (traditional counseling), while asthmatic children in advanced group were trained on inhalation technique from MDI + spacer verbally and by advanced counseling (whistling Flo-tone + smartphone application). At each visit mistakes in inhalation technique steps were; detected, corrected, and recorded and the inhalation duration was measured for every child in each group. Results: In both study groups, the total mean number of inhalation technique mistakes decreased significantly (p < 0.05) from visit 2, also the total mean inhalation durations in seconds showed a significant increase (p < 0.05) from visit 2. A significant (p < 0.05) reduction in the total mean number of mistakes and a significant (p < 0.05) increase in total mean inhalation durations were observed from visit 2 in advanced group compared to control group. Conclusion: Combination between traditional verbal and advanced counseling methods resulted in significant (P < 0.05) improvements in the number of inhalation technique mistakes and inhalation durations from MDI with spacer in children compared to using traditional verbal counseling alone.

Objective: Bromodomain-containing protein 7 (BRD7) is a key component of the switch/sucrose non-fermentable complex that participates in chromatin remodeling and transcriptional regulation. Although the emerging role of BRD7 in the pathophysiology of various diseases has been observed, its role in asthma remains unknown. Here, we assessed the function of BRD7 as a mediator of airway remodeling in asthma using an in vitro model. Methods: Airway smooth muscle cells (ASMCs) were challenged with tumor necrosis factor-α (TNF-α) to establish an in vitro airway remodeling model. Protein levels were examined using western blotting. Cell proliferation was measured using the cell counting kit-8 and 5-ethynyl-2'-deoxyuridine assays. Cell migration was assessed using a transwell migration assay. Results: Exposure to TNF-α dramatically decreased BRD7 levels in ASMCs. BRD7 remarkably decreased TNF-α-induced proliferation and migration of ASMCs. In contrast, ASMCs with BRD7 deficiency were more sensitive to TNF-α-induced pro-proliferative and pro-migratory effects. Mechanistically, BRD7 could repress the expression of Notch1 and block the Notch pathway in TNF-α-challenged cells. Notably, reactivation of Notch signaling substantially reversed the BRD7 overexpression-mediated effects, whereas restraining Notch signaling abolished BRD7-depletion-mediated effects on TNF-α-challenged cells. Conclusions: BRD7 inhibits the proliferation and migration of ASMCs elicited by TNF-α by downregulating the Notch pathway. This study indicates that BRD7 may exert a suppressive effect on airway remodeling during asthma.

Purpose: Bronchopulmonary dysplasia (BPD) is a long-term respiratory condition. More than a quarter of extremely premature newborns are harmed by BPD. At present, there are no apparent effective drugs or treatments for the condition. In this study, we aimed to investigate the functional role and mechanism of lymphoid enhancer-binding factor 1 (Lef1) in BPD in vitro.

Materials and methods: Blood samples from BPD patients and healthy volunteers were gathered, and an in vitro model of BPD was developed in alveolar epithelial cells (AECs) MLE-12 induced by hyperoxia. Then expression of krüppel-like factor 4 (KLF4/Klf4) and LEF1/Lef1 were evaluated. After Lef1 overexpressing plasmid and the vector were transfected into hyperoxia-induced MLE-12 cells, cell proliferation assays were carried out. Cell apoptosis was investigated by a flow cytometry assay, and apoptosis related proteins Bcl-2, cleaved-caspase 3 and 9 were analyzed by a western blot assay. The binding between Klf4 and Lef1 promoter predicted on the JASPAR website was verified using luciferase and ChIP assays. For further study of the mechanism of Klf4 and Lef1 in BPD, gain-of-function experiments were performed.

Results: The mRNA levels of KLF4/Klf4 and LEF1/Lef1 were diminished in clinical BPD serum samples and hyperoxia-induced MLE-12 cells. Overexpression of Lef1 stimulated AEC proliferation and suppressed AEC apoptosis induced by hyperoxia. Mechanically, Klf4 bound to Lef1's promoter region and aids transcription. Moreover, the results of gain-of-function experiments supported that Klf4 could impede AEC damage induced by hyperoxia via stimulating Lef1.

Conclusion: Klf4 and Lef1 expression levels were declined in hyperoxia-induced AECs, and Lef1 could be transcriptionally activated by Klf4 and protect against hyperoxia-induced AEC injury in BPD. As a result, Lef1 might become a prospective therapeutic target for BPD.

Background: Airway remodeling is accepted to be a determining component within the natural history of asthma. Nebulized inhalation of Mycobacterium vaccae (M. vaccae) has a protective effect on asthmatic mice. However, little is known regarding the effect of M. vaccae on airway structural remodeling in asthmatic mice. The purpose of this study was to explore the effect and the underlying mechanism of M. vaccae aerosol inhalation on airway structural remodeling in an asthma mouse model. Methods: Chronic asthma mouse models were established by ovalbumin induction. The number of inflammatory cells in bronchoalveolar lavage fluid (BALF), pathological alterations in lung tissue, and levels of associated cytokines (IL-5, IL-13, TNF-α, and ovalbumin-specific immunoglobulin E [OVA-sIgE]) were all assessed after M. vaccae therapy. The relative expression of interleukin (IL)-1β, tumor necrosis factor-alpha (TNF-α), nuclear factor kappa B (NF-κB), and Wnt1-induced signaling protein 1 (WISP1) mRNA were detected. Western blotting and immunohistochemistry detected the expression of Wnt/β-catenin pathway-related proteins in lung tissue. Results: M. vaccae aerosol inhalation relieved airway inflammation, airway hyper-responsiveness, and airway remodeling. M. vaccae reduced the levels of IL-5, IL-13, TNF-α, and OVA-sIgE in and downregulated the expression of IL-1β, TNF-α, NF-κB, and WISP1 mRNA in the pulmonary. In addition, M. vaccae inhibited the expression of β-catenin, WISP1, and Wnt1 protein and upregulated the expression of glycogen synthase kinase-3beta (GSK-3β). Conclusion: Nebulized inhalation of M. vaccae can reduce airway remodeling during asthma.

Background: Idiopathic pulmonary fibrosis (IPF) is an interstitial disease of unknown origin, characterized by tissue fibrosis, for which currently there is no effective treatment. Macrophages, the main immune cells in lung tissue, are involved in the whole process of pulmonary fibrosis. In recent years, intercellular transformation has led to wide spread concern among pulmonary fibrosis researchers. Macrophages with flexible heterogeneity and plasticity participate in different physiological processes in the body. Cell chemokine receptor 8 (CCR8) is expressed in a variety of cells and plays a significant chemotactic role in the induction of cell activation and migration. It can also promote the differentiation of macrophages under certain environmental conditions. The current study is intended to explore the role of CCR8 in macrophage to myofibroblast transdifferentiation (MMT) in IPF. Methods: We conducted experiments using CCR8-specific small interfering RNA (siRNA), an autophagy inhibitor (3-methyladenine, 3-MA), and an agonist (rapamycin) to explore the underlying mechanisms of macrophage transdifferentiation into myofibroblast cells in transforming growth factor-beta (TGF-β)-induced pulmonary fibrosis. Results: TGF-β treatment increased the CCR8 protein level in a time- and dose-dependent manner in mouse alveolar macrophages, as well as macrophage transdifferentiation-related markers, including vimentin, collagen 1, and a-SMA, and cell migration. In addition, the levels of autophagy were enhanced in macrophages treated with TGF-β. We found that 3-MA, an autophagy inhibitor, decreased the expression levels of macrophage transdifferentiation-related markers and attenuated cell migration. Furthermore, the inhibition of CCR8 via CCR8-specific siRNA reduced the levels of autophagy and macrophage transdifferentiation-related markers, and inhibited the cell migration. Enhancing autophagy with rapamycin attenuated the inhibition effect of CCR8-specific siRNA on macrophage migration and the increase in myofibroblast marker proteins. Conclusions: Our findings showed that the macrophages exposed to TGF-β had the potential to transdifferentiate into myofibroblasts and CCR8 was involved in the process. The effect of CCR8 on TGF-β-induced macrophage transdifferentiation occurs mainly through autophagy. Targeting CCR8 may be a novel therapeutic strategy for the treatment of IPF.