Dataset Information

Cigarette smoke-induced impairment of autophagy in macrophages increases galectin-8 and inflammation.

ABSTRACT: Cigarette smoke impairs autophagy, an intracellular protein degradation system, but the consequences of this defect have not been fully elucidated, especially in macrophages. Dysfunctional alveolar macrophages play an important role in chronic obstructive pulmonary disease (COPD). Here we show that galectin-8, a danger receptor that identifies damaged intracellular host vesicles and initiates autophagosome engulfment, is elevated due to activation of autophagy by cigarette smoke extract (CSE) in macrophages. CSE impaired autophagic flux in PMA-differentiated U937 macrophage-like cells, resulting in intracellular accumulation of galectin-8 and the autophagic adaptor protein NDP52. COPD patients showed elevated levels of galectin-8 and NDP52 in the lung homogenates with significant increase in the serum galectin-8 levels in patients with frequent acute exacerbations. Soluble galectin-8 induced interleukin (IL)-6 release in bronchial epithelial cells via PI3K? signalling. Thus, increased galectin-8 due to CSE-induced impaired autophagy may be involved in the pathogenesis of COPD and may be a biomarker of this disease.

SUBMITTER: Kono Y

PROVIDER: S-EPMC7801483 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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Cigarette smoke-induced impairment of autophagy in macrophages increases galectin-8 and inflammation.

Kono Yuta Y Colley Thomas T To Masako M Papaioannou Andriana I AI Mercado Nicolas N Baker Jonathan R JR To Yasuo Y Abe Shinji S Haruki Kosuke K Ito Kazuhiro K Barnes Peter J PJ

Scientific reports 20210111 1

Cigarette smoke impairs autophagy, an intracellular protein degradation system, but the consequences of this defect have not been fully elucidated, especially in macrophages. Dysfunctional alveolar macrophages play an important role in chronic obstructive pulmonary disease (COPD). Here we show that galectin-8, a danger receptor that identifies damaged intracellular host vesicles and initiates autophagosome engulfment, is elevated due to activation of autophagy by cigarette smoke extract (CSE) in ...[more]

PMID: 33432024

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Project description:Age related macular degeneration (AMD) is one of the leading causes of blindness. Genetics, environmental insult, and age-related factors all play a key role in altering proteostasis, the homeostatic process regulating protein synthesis, degradation and processing. These factors also play a role in the pathogenesis of AMD and it has been well established that cigarette smoking (CS) initiates AMD pathogenic mechanisms. The primary goal of this study is to elucidate whether CS can induce proteostasis/autophagy-impairment in retinal pigment epithelial (RPE) cells. In our preliminary analysis, it was found that cigarette smoke extract (CSE) induces accumulation of ubiquitinated proteins in the insoluble protein fraction (p < 0.01), which was subsequently mitigated through cysteamine (p < 0.01) or fisetin (p < 0.05) treatment. Further, it was verified that these CSE induced ubiquitinated proteins accumulated in the peri-nuclear spaces (p<0.05) that were cleared- off with cysteamine (p < 0.05) or fisetin (p < 0.05). Moreover, CSE-induced aggresome-formation (LC3B-GFP and Ub-RFP co-localization) and autophagy-flux impairment was significantly (p<0.01) mitigated by cysteamine (p<0.05) or fisetin (p<0.05) treatment, indicating the restoration of CSE-mediated autophagy-impairment. CSE treatment was also found to induce intracellular reactive oxygen species (ROS, p < 0.001) while impacting cell viability (p < 0.001), which was quantified using CMH2DCFDA-dye (ROS) and MTS (proliferation) or propodium iodide staining (cell viability) assays, respectively. Moreover, cysteamine and fisetin treatment ameliorated CS-mediated ROS production (p < 0.05) and diminished cell viability (p < 0.05). Lastly, CSE was found to induce cellular senescence (p < 0.001), which was significantly ameliorated by cysteamine (p < 0.001) or fisetin (p < 0.001). In conclusion, our study indicates that CS induced proteostasis/autophagy-impairment regulates mechanisms associated with AMD pathogenesis. Moreover, autophagy-inducing drugs such as cysteamine or fisetin can ameliorate AMD pathogenesis mechanisms that warrant further investigation in pre-clinical murine models.

Project description:Asthma is an allergic lung disease and, when associated to cigarette smoke exposition, some patients show controversial signs about lung function and other inflammatory mediators. Epidemiologic and experimental studies have shown both increasing and decreasing inflammation in lungs of subjects with asthma and exposed to cigarette smoke. Therefore, in this study, we analyzed how cigarette smoke affects pro-inflammatory and anti-inflammatory mediators in a murine model of allergic pulmonary inflammation. We sensitized Balb/c mice to ovalbumin (OVA) with two intraperitoneal injections. After sensitization, the animals were exposed to cigarette smoke twice a day, 30?min per exposition, for 12 consecutive days. In order to drive the cell to the lungs, four aerosol challenges were performed every 48?h with the same allergen of sensitization. OVA sensitization and challenge developed pulmonary Th2 characteristic response with increased airway responsiveness, remodeling, increased levels of IgE, interleukin (IL)-4, and IL-13. Cigarette smoke, unexpectedly, reduced the levels of IL-4 and IL-13 and simultaneously decreased anti-inflammatory cytokines as IL-10 and transforming growth factor (TGF)-? in sensitized and challenged animals. OVA combined with cigarette smoke exposition decreased the number of eosinophils in bronchoalveolar lavage and increased the number of neutrophils in lung. The combination of cigarette smoke and lung allergy increased recruitment of lymphoid dendritic cells (DCs) into lymph nodes, which may be the leading cause to an increase in number and activation of CD8+ T cells in lungs. In addition, lung allergy and cigarette smoke exposure decreased an important regulatory subtype of DC such as plasmacytoid DC as well as its activation by expression of CD86, PDL2, and ICOSL, and it was sufficient to decrease T regs influx and anti-inflammatory cytokines release such as IL-10 and TGF-? but not enough to diminish the structural changes. In conclusion, we observed, in this model, that OVA sensitization and challenge combined with cigarette smoke exposure leads to mischaracterization of the Th2 response of asthma by decreasing the number of eosinophils, IL-4, and IL-13 and increasing number of neutrophils, which is related to the increased number of CD8?+ DCs and CD8+ T cells as well as reduction of the regulatory cells and its released cytokines.

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Project description:BackgroundCD147 is expressed in many tissues and is involved in many inflammatory diseases. Emerging evidence suggests that the overproduction of mucus is a malignant factor in chronic obstructive pulmonary disease (COPD), which results in severe airway obstruction and repeated airway infections. However, it is still unclear whether CD147 is involved in mucus production in COPD.MethodsWe determined the expression levels of CD147 and MUC5AC by immunohistochemistry in 42 human lung specimens from three groups (non-smokers without COPD, smokers without COPD and smokers with COPD). For the in vitro experiment, human bronchial epithelial (HBE) cells were treated with cigarette smoke (CS) extract to establish a mucus secretion model; then, CD147 and MUC5AC production were detected by RT-PCR, Western blotting and ELISA. To determine how CD147 is involved in MUC5AC secretion, HBE cells were transfected with small interfering RNA to silence CD147 and pretreated with inhibitors of MMP9 and p38 MAPK, which are common signaling molecules involved in MUC5AC secretion; then, MUC5AC expression was evaluated.ResultsCompared with the expression levels in the non-smokers and smokers without COPD, CD147 and MUC5AC expression levels were higher in the smokers with COPD. In the in vitro experiment, CD147 and MUC5AC expression levels were significantly increased after CS extract incubation compared with those after no treatment. Silencing CD147 by siRNA decreased the CS extract-induced MUC5AC secretion and MMP9 and phosphorylated p38 MAPK production. In addition, inhibiting MMP9 or p38 MAPK decreased the CS extract-induced MUC5AC secretion.ConclusionsIn lung specimens, CD147 and MUC5AC expression levels were increased in COPD patients. Increased CD147 levels induced by CS extract could stimulate MUC5AC secretion through the MMP9 and p38 MAPK signaling pathway in HBE cells. Therefore, the regulation of CD147 could be a promising target for mucus hypersecretion in COPD.

Dataset Information

Cigarette smoke-induced impairment of autophagy in macrophages increases galectin-8 and inflammation.

Publications

Cigarette smoke-induced impairment of autophagy in macrophages increases galectin-8 and inflammation.

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