Impaired activation of Notch-1 signaling hinders repair processes of bronchial epithelial cells exposed to cigarette smoke

Increased TSLP and oxidative stress reflect airway epithelium injury upon cigarette smoke exposure. Is there a role for carbocysteine?

Chronic Obstructive Pulmonary Disease (COPD) is a chronic inflammatory degenerative disease. Disease exacerbations accelerate lung function deterioration. Airway epithelium has a central role in COPD pathophysiology. Airway epithelium releases alarmins including the thymic stromal lymphopoietin (TSLP) in response to exogenous stressors. Notch-1 in the nucleus acts as inhibitor of TSLP gene expression. Here, we investigated, in human bronchial epithelial cells, the effects of cigarette smoke extract (CSE) in TSLP production exploring the relationship with oxidative stress events and with Notch-1 signaling. In CSE exposed 16HBE, the effects of carbocysteine were assessed on: intracellular and extracellular oxidative stress; nuclear Notch-1 expression; TSLP gene expression. The TSLP levels in sera from non-smokers, smokers and exacerbated COPD patients (before and after therapy with carbocysteine) were also explored. CSE induced TSLP gene expression and oxidative stress and reduced nuclear expression of Notch-1 in 16HBE. The use of an electrochemical sensor allowed a reliable tool to assess oxidative stress. TSLP concentrations were higher in sera from smokers and exacerbated COPD than in sera from non-smokers. Carbocysteine was able to counteract the effects of CSE in oxidative stress and in TSLP gene expression in 16HBE and to reduce TSLP in exacerbated COPD. In conclusion, increased oxidative stress induced by smoke exposure in airway epithelium leads to increased TSLP production and carbocysteine in vitro and in vivo mitigates the induced TSLP production. Oxidative stress detection by electrochemical sensors can open new avenues for evaluating epithelial damage and for identifying patients eligible to alarmin targeted biologics.

Stem cells, Notch-1 signaling, and oxidative stress: a hellish trio in cancer development and progression within the airways. Is there a role for natural compounds?

Notch-1 signaling plays a crucial role in stem cell maintenance and in repair mechanisms in various mucosal surfaces, including airway mucosa. Persistent injury can induce an aberrant activation of Notch-1 signaling in stem cells leading to an increased risk of cancer initiation and progression. Chronic inflammatory respiratory disorders, including chronic obstructive pulmonary disease (COPD) is associated with both overactivation of Notch-1 signaling and increased lung cancer risk. Increased oxidative stress, also due to cigarette smoke, can further contribute to promote cancer initiation and progression by amplifying inflammatory responses, by activating the Notch-1 signaling, and by blocking regulatory mechanisms that inhibit the growth capacity of stem cells. This review offers a comprehensive overview of the effects of aberrant Notch-1 signaling activation in stem cells and of increased oxidative stress in lung cancer. The putative role of natural compounds with antioxidant properties is also described.

Ferulic acid, ligustrazine, and tetrahydropalmatine display the anti-proliferative effect in endometriosis through regulating Notch pathway

AIMS

With an ambiguous anti-proliferative mechanism, the combination of ferulic acid, ligustrazine, and tetrahydropalmatine (FLT) shows good anti-endometriosis (EMS) activity. In EMS, the expression of Notch pathway and its role in proliferation are not yet unclear. In this study, we sought to uncover the role of Notch pathway's effect and FLT's anti-proliferative mechanism on EMS proliferation.

MAIN METHODS

In autograft and allograft EMS models, the proliferating markers (Ki67, PCNA), Notch pathway, and the effect of FLT on them were detected. Then, the anti-proliferative influence of FLT was measured in vitro. The proliferating ability of endometrial cells was investigated with a Notch pathway activator (Jagged 1 or VPA) or inhibitor (DAPT) alone, or in combination with FLT separately.

KEY FINDINGS

FLT presented the inhibitory effect on ectopic lesions in 2 EMS models. The proliferating markers and Notch pathway were promoted in ectopic endometrium, but FLT showed the counteraction. Meantime, FLT restrained the endometrial cell growth and clone formation along with a reduction in Ki67 and PCNA. Jagged 1 and VPA stimulated the proliferation. On the contrary, DAPT displayed the anti-proliferating effect. Furthermore, FLT exhibited an antagonistic effect on Jagged 1 and VPA by downregulating Notch pathway and restraining proliferation. FLT also displayed a synergistic effect on DAPT.

SIGNIFICANCE

This study indicated that the overexpressing Notch pathway induced EMS proliferation. FLT attenuated the proliferation by inhibiting Notch pathway.

Effects of condensates from volcanic fumaroles and cigarette smoke extracts on airway epithelial cells

The impact of volcanic airborne products on airway epithelium homeostasis is largely unknown. This study assessed the effects of volcanic Fumarole Condensates (FC) alone or combined with Cigarette Smoke Extracts (CSE) on airway epithelial cells (16HBE and A549). Chemical composition of FC was analyzed by gas chromatography and HPLC. Cells were exposed to FC and IL-33 and IL-8 were assessed. The effects of FC and CSE on cell injury were evaluated assessing cell metabolism/cell viability, mitochondrial stress, cell apoptosis/cell necrosis, and cell proliferation. FC contained: water vapor (70-97%), CO2 (3-30%), acid gases (H2S, SO2, HCl, HF) around 1%. FC increased the intracellular IL-33 but differently modulated IL-33 and IL-8 gene expression and IL-8 release in the tested cell lines. FC without/with CSE: (a) increased cell metabolism/cell viability in 16HBE, while decreased it in A549; (b) increased mitochondrial stress in both cell types. FC with CSE increased cell necrosis in A549 in comparison to CSE alone. CSE reduced cell proliferation in 16HB,E while increased it in A549 and FC counteracted these effects in both cell types. Overall, FC induce a pro-inflammatory profile associated to a metabolic reprogramming without a relevant toxicity also in presence of CSE in airway epithelial cells.

Wenshen Yiqi Keli Mitigates the Proliferation and Migration of Cigarette Smoke Extract-Induced Human Airway Smooth Muscle Cells through miR-155/FoxO3a Axis

Some domestic scholars revealed the effectiveness of Wenshen Yiqi Keli (WSYQKL) on chronic obstructive pulmonary disease (COPD). However, the exact mechanism of WSYQKL on COPD is fuzzy and needs further research. We adopted UPLC-Q/TOF-MS to analyze the chemical components of WSYQKL. In in vitro experiments, human airway smooth muscle cells (hASMCs) were intervened with 2.5% cigarette smoke extract (CSE), medicine serum of WSYQKL, miR-155 mimic, and FoxO3a silencing. Cell viability, proliferation, migration, and the expressions of miR-155, PCNA, Ki67, p21, p27, and FoxO3a were examined by cell counting kit-8, EdU staining, Transwell assay, scarification assay, qRT-PCR, immunol cytochemistry, and western blot, respectively. The association between miR-155 and FoxO3a was assessed by database and luciferase reporter gene analysis. We identified 47 kinds of chemical compositions of WSYQKL in ESI+ mode and 42 kinds of components of WSYQKL in ESI− mode. The medicine serum of WSYQKL strongly alleviated the proliferation and migration of hASMCs induced by CSE in a concentration-dependent manner. The medicine serum of WSYQKL enhanced the levels of p21, p27, and FoxO3a and weakened PCNA and Ki67 levels in hASMCs induced by CSE with the increase of concentration. MiR-155 mimic or FoxO3a silencing notably advanced CSE-treated HASMC viability, proliferation, migration, and the levels of PCNA and Ki67 and downregulated the levels of p21, p27, and FoxO3a in CSE-triggered hASMCs, which was reversed by WSYQKL-containing serum. Our results described that WSYQKL alleviated the proliferation and migration of hASMCs induced by CSE by modulating the miR-155/FoxO3a axis.

Cigarette Smoke Impairs Airway Epithelial Wound Repair: Role of Modulation of Epithelial-Mesenchymal Transition Processes and Notch-1 Signaling

Cigarette smoke (CS) induces oxidative stress and chronic inflammation in airway epithelium. It is a major risk factor for respiratory diseases, characterized by epithelial injury. The impact of CS on airway epithelial repair, which involves epithelial-mesenchymal transition (EMT) and the Notch-1 pathway, is incompletely understood. In this study, we used primary bronchial epithelial cells (PBECs) to evaluate the effect of CS on epithelial repair and these mechanisms. The effect of CS and/or TGF-beta1 on wound repair, various EMT and Notch-1 pathway markers and epithelial cell markers (TP63, SCGB1A) was assessed in PBECs cultured submerged, at the air–liquid interface (ALI) alone and in co-culture with fibroblasts. TGF-beta1 increased epithelial wound repair, activated EMT (shown by decrease in E-cadherin, and increases in vimentin, SNAIL1/SNAIL2/ZEB1), and increased Notch-1 pathway markers (NOTCH1/JAGGED1/HES1), MMP9, TP63, SCGB1A1. In contrast, CS decreased wound repair and vimentin, NOTCH1/JAGGED1/HES1, MMP9, TP63, SCGB1A1, whereas it activated the initial steps of the EMT (decrease in E-cadherin and increases in SNAIL1/SNAIL2/ZEB1). Using combined exposures, we observed that CS counteracted the effects of TGF-beta1. Furthermore, Notch signaling inhibition decreased wound repair. These data suggest that CS inhibits the physiological epithelial wound repair by interfering with the normal EMT process and the Notch-1 pathway.

Exploration of potential mechanism of interleukin-33 up-regulation caused by 1,4-naphthoquinone black carbon in RAW264.7 cells

BACKGROUND

As air pollution has been paid more attention to by public in recent years, effects and mechanism in particulate matter-triggered health problems become a focus of research. Lysosomes and mitochondria play an important role in regulation of inflammation. Interleukin-33 (IL-33) has been proved to promote inflammation in our previous studies. In this research, macrophage cell line RAW264.7 was used to explore the potential mechanism of upregulation of IL-33 induced by 1,4-naphthoquinone black carbon (1,4-NQ-BC), and to explore changes of lysosomes and mitochondria during the process.

RESULTS

50 μg/mL 1,4-NQ-BC exposure for 24 h dramatically increased expression of IL-33 in RAW264.7 cells. Lysosomal membrane permeability was damaged by 1,4-NQ-BC treatment, and higher mitochondrial membrane potential and ROS level were induced by 1,4-NQ-BC. The results of proteomics suggested that expression of ferritin light chain was increased after cells were challenged with 1,4-NQ-BC, and it was verified by Western blot. Meanwhile, expressions of p62 and LC3B-II were increased by 50 μg/mL 1,4-NQ-BC in RAW264.7 cells. Ultimately, expression of IL-33 could return to same level as control in cells treated with 50 μg/mL 1,4-NQ-BC and 50 μM deferoxamine combined.

CONCLUSIONS

1,4-NQ-BC induces IL-33 upregulation in RAW264.7 cells, and it is responsible for higher lysosomal membrane permeability and ROS level, lower mitochondrial membrane potential, and inhibition of autophagy. Ferritin light chain possibly plays an important role in the upregulation of IL-33 evoked by 1,4-NQ-BC.

Cigarette smoke upregulates Notch-1 signaling pathway and promotes lung adenocarcinoma progression

Notch-1 pathway plays an important role in lung carcinoma, stem cell regulation, cellular communication, growth and differentiation. Cigarette smoke is involved in the regulation of Notch signaling. However, current data regarding the impact of cigarette smoke on the Notch pathway in lung cancer progression are limited. The present study aimed to explore whether cigarette smoke exposure altered Notch-1 pathway in ex-vivo (surgical samples of lung parenchyma from non-smoker and smoker patients with lung adenocarcinoma) and in vitro (adenocarcinoma A549 cell line) approaches. The expression of Notch-1, Jagged-1 and CD133 in surgical samples was evaluated by immunohistochemistry. A549 were exposed to cigarette smoke extracts (2.5% and 5% CSE for 6, 24 and 48 h) and the expression of Notch-1, Jagged-1 and Hes-1 was evaluated by Real-Time PCR and Western Blot (nuclear fractions). Expression and localization of Notch-1, Hes-1, CD133 and ABCG2 were assessed by immunofluorescence. The expression of survivin and Ki-67 was assessed by flow cytometry following CSE exposure and inhibition of Notch-1 signaling. Smokers lung parenchyma exhibited higher expression of Notch-1. CSE exposure increased Notch-1 and Hes-1 gene and nuclear protein expression in A549. Immunofluorescence confirmed higher expression of nuclear Hes-1 in CSE-stimulated A549 cells. CSE increased both survivin and Ki-67 expression and this effect was reverted by inhibition of the Notch-1 pathway. In conclusion, these data show that cigarette smoke may promote adenocarcinoma progression by activating the Notch-1 pathway thus supporting its role as hallmark of lung cancer progression and as a new target for lung cancer treatment.

Changes in Eustachian Tube Mucosa in Mice After Short-Term Tobacco and E-cigarette Smoke Exposure

OBJECTIVES

To evaluate histologic changes in middle ear and eustachian tube (ET) mucosa of mice after exposure to tobacco or electronic cigarette (e-cigarette) smoke. To determine whether there were any mitigating effects of middle ear application of anti-IL-13 or the epidermal growth factor receptor antagonist AG1478 on noted changes within ET mucosa.

STUDY DESIGN

Controlled animal study.

METHODS

Fifty BALB/cJ mice were randomly assigned to one of five groups: A control group with no smoke exposure, two groups exposed to tobacco smoke, and two groups exposed to e-cigarette vapor. Within the exposed groups after 4 weeks of exposure, one ear was infiltrated with a saline hydrogel and the other ear with hydrogel of either Anti-IL-13 or AG1478. After four more weeks of exposure, the animals were euthanized and the ETs were evaluated for mucosal changes.

RESULTS

Compared to control animals with no smoke exposure, there were significant decreases in the numbers of goblet cells within the ET mucosa of mice exposed to tobacco smoke and e-cigarette vapor. No significant differences in cilia, mucin, or squamous metaplasia were noted. Neither anti-IL-13 nor AG178 significantly altered goblet cell count in the ET mucosa of mice exposed to tobacco smoke; however, both agents significantly increased goblet cells within the ET mucosa of mice exposed to e-cigarette vapor.

CONCLUSION

Short-term tobacco smoke and e-cigarette vapor significantly decrease goblet cell count in mouse ET mucosa. Middle ear application of both anti-IL-13 and AG1478 resulted in an increase in goblet cell count among mice exposed to e-cigarette vapor, but not to tobacco smoke.

LEVEL OF EVIDENCE

NA Laryngoscope, 2021.