Inhalation of ambroxol inhibits cigarette smoke-induced acute lung injury in a mouse model by inhibiting the Erk pathway

iNOS inhibitor S-methylisothiourea alleviates smoke inhalation-induced acute lung injury by suppressing inflammation and macrophage infiltration

OBJECTIVE

We investigated the effects of the inducible NO synthase (iNOS) inhibitor, S-methylisothiourea (SMT), in a mouse model of smoke inhalation-induced acute lung injury (ALI) and explored the underlying molecular mechanism.

METHODS AND ANALYSIS

A mouse model of smoke inhalation-induced ALI was established. RNA-sequencing (seq) analysis was conducted to identify the differentially expressed genes (DEGs). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed for functional annotation of DEGs. Moreover, an immunofluorescence assay using macrophage marker F4/80 was performed to assess macrophage infiltration. A hypoxia-induced HUVEC model was used to mimic smoke inhalation-induced injury in endothelial cells. Finally, a transwell assay was used to analyze the chemoattractive effects of endothelial cells on macrophages.

RESULTS

SMT markedly alleviated the pulmonary pathological symptoms, edema, and inflammatory response in the mouse smoke inhalation-induced ALI model. RNA-seq analysis revealed that SMT may diminish lung injury by regulating the levels of genes associated with inflammatory responses, cell chemokines, and adhesion. In vivo data revealed that the protective effects of SMT against smoke inhalation-induced ALI were partly achieved by inhibiting the production of adhesion molecules and infiltration of macrophages. Furthermore, in vitro data from the hypoxia-induced HUVEC model revealed that SMT reduced macrophage chemotaxis by inhibiting the production of chemokines and adhesion molecules in endothelial cells.

CONCLUSION

iNOS inhibitor SMT protects the lungs from smoke inhalation-induced ALI by reducing the production of pro-inflammatory cytokines, adhesion molecules, and chemokines in endothelial cells, thereby inhibiting inflammation and macrophage infiltration.

Inhibition of TRPA1, Endoplasmic Reticulum Stress, Human Airway Epithelial Cell Damage, and Ectopic MUC5AC Expression by Vasaka (Adhatoda vasica; Malabar Nut) Tea

This study tested whether a medicinal plant, Vasaka, typically consumed as a tea to treat respiratory malaise, could protect airway epithelial cells (AECs) from wood smoke particle-induced damage and prevent pathological mucus production. Wood/biomass smoke is a pneumotoxic air pollutant. Mucus normally protects the airways, but excessive production can obstruct airflow and cause respiratory distress. Vasaka tea pre- and co-treatment dose-dependently inhibited mucin 5AC (MUC5AC) mRNA induction by AECs treated with wood smoke particles. This correlated with transient receptor potential ankyrin-1 (TRPA1) inhibition, an attenuation of endoplasmic reticulum (ER) stress, and AEC damage/death. Induction of mRNA for anterior gradient 2, an ER chaperone/disulfide isomerase required for MUC5AC production, and TRP vanilloid-3, a gene that suppresses ER stress and wood smoke particle-induced cell death, was also attenuated. Variable inhibition of TRPA1, ER stress, and MUC5AC mRNA induction was observed using selected chemicals identified in Vasaka tea including vasicine, vasicinone, apigenin, vitexin, isovitexin, isoorientin, 9-oxoODE, and 9,10-EpOME. Apigenin and 9,10-EpOME were the most cytoprotective and mucosuppressive. Cytochrome P450 1A1 (CYP1A1) mRNA was also induced by Vasaka tea and wood smoke particles. Inhibition of CYP1A1 enhanced ER stress and MUC5AC mRNA expression, suggesting a possible role in producing protective oxylipins in stressed cells. The results provide mechanistic insights and support for the purported benefits of Vasaka tea in treating lung inflammatory conditions, raising the possibility of further development as a preventative and/or restorative therapy.

Recent advancements and application of in vitro models for predicting inhalation toxicity in humans

Animals have been indispensable in testing chemicals that can pose a risk to human health, including those delivered by inhalation. In recent years, the combination of societal debate on the use of animals in research and testing, the drive to continually enhance testing methodologies, and technology advancements have prompted a range of initiatives to develop non-animal alternative approaches for toxicity testing. In this review, we discuss emerging in vitro techniques being developed for the testing of inhaled compounds. Advanced tissue models that are able to recreate the human response to toxic exposures alongside examples of their ability to complement in vivo techniques are described. Furthermore, technology being developed that can provide multi-organ toxicity assessments are discussed.

Study on the Efficacy and Safety of Ambroxol Combined with Methylprednisolone in Patients with Acute Lung Injury

Background

There is no better treatment method towards paraquat-induced acute lung injury (ALI) at present. Ambroxol combined with methylprednisolone exhibits a significant improvement effect on ALI treatment, whereas their mechanism in ALI is still unclear.

Methods

64 patients with ALI caused by paraquat poisoning brought to our hospital from January 2015 to January 2018 were selected. They were separated into a combined treatment group (CTG) and a routine treatment group (RTG) on the basis of different treatment methods. The survival of patients was observed after 7 days of treatment. Arterial blood gas, oxygen partial pressure (PaO₂), partial pressure of carbon dioxide (PaCO₂), oxygenation index (PaO₂/FiO₂), patient's spontaneous respiratory rate (RR), tidal volume (VT), and positive end-expiratory pressure (PEEP) were observed before and after treatment for 7 days. Interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) were analyzed. The differences of indexes between the dead patients and the survivors were observed, and the potential predictive value of death was analyzed.

Results

After treatment, the indexes of patients were significantly improved in both groups compared with those before therapy. Further comparison showed that the improvement of PaO₂, PaCO₂, and PaO₂/FiO₂ in CTG was obviously higher than that in RTG (p < 0.05). The improvement of RR, PEEP, and VT in CTG was obviously higher than that in RTG (p < 0.05). The decreased degree of IL-6 and TNF-α in CTG was higher than that in RTG (p < 0.05). The 7-day mortality rate of 64 patients was 39.06%, and there was no obvious difference in the 7-day survival rate in both groups (p = 0.649). IL-6 and TNF-α were expected to be potential prediction indexes of paraquat-induced ALI.

Conclusion

Ambroxol combined with methylprednisolone significantly improved the oxygen partial pressure and oxygenation index of patients with paraquat-induced ALI and inhibited the inflammatory response of patients.

Friend or Foe? The Roles of Antioxidants in Acute Lung Injury

Acute lung injury (ALI) is an acute hypoxic respiratory insufficiency caused by various intra- and extra-pulmonary injury factors. The oxidative stress caused by excessive reactive oxygen species (ROS) produced in the lungs plays an important role in the pathogenesis of ALI. ROS is a "double-edged sword", which is widely involved in signal transduction and the life process of cells at a physiological concentration. However, excessive ROS can cause mitochondrial oxidative stress, leading to the occurrence of various diseases. It is well-known that antioxidants can alleviate ALI by scavenging ROS. Nevertheless, more and more studies found that antioxidants have no significant effect on severe organ injury, and may even aggravate organ injury and reduce the survival rate of patients. Our study introduces the application of antioxidants in ALI, and explore the mechanisms of antioxidants failure in various diseases including it.

Baicalin alleviates chronic obstructive pulmonary disease through regulation of HSP72-mediated JNK pathway

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterized by airway obstruction and progressive lung inflammation. As the primary ingredient of a traditional Chinese medical herb, Baicalin has been previously shown to possess anti-inflammatory abilities. Thus, the current study aimed to elucidate the mechanism by which baicalin alleviates COPD.

METHODS

Baicalin was adopted to treat cigarette smoke in extract-exposed MLE-12 cells after which cell viability and apoptosis were determined. The production of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), IL-8 were determined by enzyme-linked immunoassay. A COPD mouse model was constructed via exposure to cigarette smoke and lipopolysaccharide, baicalin treatment. Lung function and inflammatory cell infiltration were determined and the production of Muc5AC, TNF-α, IL-6, IL-8 in the bronchoalveolar lavage fluid (BALF) was assayed by ELISA. The effect of HSP72 and JNK on COPD following treatment with baicalin was assessed both in vivo and in vitro by conducting loss- and gain- function experiments.

RESULTS

Baicalin improved lung function evidenced by reduction in inflammatory cell infiltration and Muc5AC, TNF-α, IL-6 and IL-8 levels observed in BALF in mice. Baicalin was further observed to elevate cell viability while inhibited apoptosis and TNF-α, IL-6 and IL-8 levels in MLE-12 cells. Baicalin treatment increased HSP72 expression, while its depletion reversed the effect of baicalin on COPD. HSP72 inhibited the activation of JNK, while JNK activation was found to inhibit the effect of baicalin on COPD.

CONCLUSIONS

Baicalin upregulated the expression of HSP72, resulting in the inhibition of JNK signaling activation, which ultimately alleviates COPD.

TLR3 inhibitor and tyrosine kinase inhibitor attenuate cigarette smoke/poly I:C-induced airway inflammation and remodeling by the EGFR/TLR3/MAPK signaling pathway

Tobacco smoke is the major risk factor for developing chronic obstructive pulmonary disease (COPD). Viral infection is a major cause of COPD exacerbation, which lacks effective drug treatments. In the present study, to mimic the pathogenesis of COPD, we employed a TLR3 ligand [Poly (I:C), PIC] to mimic viral infection to determine whether it enhances the effects of cigarette smoke (CS)-induced airway inflammation and remodeling. Our results showed that PIC enhanced the effects of cigarette smoke extract (CSE)-induced inflammatory cytokine IL-1β, TNF-α and IL-8 mRNA expression and remodeling factor E-cadherin, α-SMA and TGF-β1 mRNA expression with TLR3 upregulation and EGFR phosphorylation in pulmonary epithelial NCI-H292 cells. These responses were inhibited by a TLR3/dsRNA complex inhibitor (TLR3i) or a tyrosine kinase inhibitor icotinib (Ico). Similarly, in the PIC-enhanced CS-induced airway inflammation and remodeling mouse model, treatment with TLR3i or Ico reduced the mRNA and protein expression of the inflammatory cytokines IL-1β and TNF-α and keratinocyte chemoattractant (KC) and the remodeling factors α-SMA, TGF-β1, MMP-9 and MUC5AC, while increasing E-cadherin mRNA and protein expression. Furthermore, we found that TLRi and Ico can attenuate the airway hyperreactivity induced by PIC, which is enhanced by CS. Finally, PIC enhanced the effects of CS on TLR3 upregulation and EGFR phosphorylation and significantly increased Erk1/2 and P38 phosphorylation, whereas TLR3i and Ico markedly suppressed TLR3 upregulation and EGFR, Erk1/2 and P38 phosphorylation in the model. Our findings suggest that TLR3/EGFR may be a potential target for the treatment of airway inflammation and remodeling in COPD.

Role of the mucins in pathogenesis of COPD: implications for therapy

Introduction: Evidence accumulated in the last decade has started to reveal the enormous complexity in the expression, interactions and functions of the large number of different mucins present in the different compartments of the human lower airways. This occurs both in normal subjects and in COPD patients in different clinical phases and stages of severity.Areas covered: We review the known physiological mechanisms that regulate mucin production in human lower airways of normal subjects, the changes in mucin synthesis/secretion in COPD patients and the clinical efficacy of drugs that modulate mucin synthesis/secretion.Expert opinion: It is evident that the old simplistic concept that mucus hypersecretion in COPD patients is associated with negative clinical outcomes is not valid and that the therapeutic potential of 'mucolytic drugs' is under-appreciated due to the complexity of the associated molecular network(s). Likewise, our current knowledge of the effects of the drugs already available on the market that target mucin synthesis/secretion/structure in the lower airways is extremely limited and often indirect and more well-controlled clinical trials are needed in this area.

So-Cheong-Ryoung-Tang Attenuates Pulmonary Inflammation Induced by Cigarette Smoke in Bronchial Epithelial Cells and Experimental Mice

So-Cheong-Ryoung-Tang is a traditionally used herbal formula for the treatment of pulmonary diseases in China, Korea, and Japan. We investigated the protective effects of So-Cheong-Ryong-Tang water extract (SCWE) in cigarette smoke concentrate (CSC) stimulated human airway epithelial cell line NCI-H292 and mice exposed cigarette smoke (CS) and lipopolysaccharide (LPS). In the CSC-stimulated NCI-H292 cells, SCWE inhibited proinflammatory cytokines in a concentration-dependent manner, as evidenced by a reduction in their mRNA levels. Also, SCWE significant reduced inducible nitric oxide synthase (iNOS) expression and nuclear factor kappa B (NF-κB) phosphorylation in CSC-stimulated cells. The mice were exposed to CS for 1 h per day (a total of eight cigarettes per day) for 7 days and received LPS intranasally on day 5. The mice were administered a dose of SCWE (100 and 200 mg/kg) 1 h before CS exposure. In in vivo, SCWE decreased the inflammatory cell count and reduced the expression of the proinflammatory cytokines in the broncho-alveolar lavage fluid (BALF) compared with CS and LPS exposed mice. SCWE attenuated inflammatory cell infiltration in airway induced by CS and LPS exposure, and this decrease was accompanied by a reduction in the expression levels of iNOS and MMP-9 in lung tissue. The extract also inhibited the phosphorylation of inhibitor of kappa B alpha (IκBα) and NF-κB induced by CS and LPS exposure in lung tissue. These results suggest that SCWE may effectively inhibit airway inflammatory responses induced by CS and LPS exposure via the NF-κB pathway. Therefore, SCWE may be a potential treatment for airway inflammatory diseases, such as chronic obstructive pulmonary disease (COPD).

Phloretin attenuates mucus hypersecretion and airway inflammation induced by cigarette smoke

BACKGROUNDS

Cigarette smoke (CS)-induced airway mucus hypersecretion and inflammation are the prominent features of chronic obstructive pulmonary disease (COPD). As an anti-inflammatory flavonoid, phloretin was found to be involved in various inflammatory disorders such as sepsis. In this study, the effects of phloretin on CS-induced airway mucin secretion and inflammation were investigated in vivo and in vitro.

METHODS

Phloretin dissolved in 1% DMSO was daily injected intraperitoneally to mice, which were then exposed to CS for four weeks. Mouse lung histologic changes were evaluated, the expression of mucin 5ac (MUC5AC) was measured, bronchoalveolar lavage fluid (BALF) total cells, neutrophils, and macrophages were counted. BALF and lung levels of tumor necrosis factor-alpha and interleukin-1 beta (IL-1β) were quantified. Moreover, the effects of phloretin on cigarette smoke extract (CSE)-induced expression of MUC5AC and IL-1β were investigated in NCI-H292 cells. Then, to explore the potential mechanisms, the signaling molecules including epidermal growth factor receptor (EGFR), extracellular signal-regulated kinase (ERK) and P38 were evaluated.

RESULTS

Phloretin pretreatment dramatically suppressed the mucins secretion, inflammatory cell infiltration and inflammatory cytokine release in mouse lungs induced by CS, and it also suppressed CSE-induced expression of MUC5AC and IL-1β in NCI-H292 bronchial epithelial cells. Furthermore, western blot showed that phloretin attenuated the activation of EGFR, ERK and P38 both in vivo and in vitro.

CONCLUSIONS

This study highlights the protective effect of phloretin on CS-related airway mucus hypersecretion and inflammation, where EGFR, ERK and P38 might be involved. These findings suggest that phloretin could be a potential therapeutic drug for COPD.

Physalis peruviana L. inhibits airway inflammation induced by cigarette smoke and lipopolysaccharide through inhibition of extracellular signal-regulated kinase and induction of heme oxygenase-1

Physalis peruviana L. (PP) is a medicinal herb that has been confirmed to have several biological activities, including anticancer, antioxidant and anti-inflammatory properties. The aim of the present study was to evaluate the protective effect of PP on cigarette smoke (CS)- and lipopolysaccharide (LPS)-induced pulmonary inflammation. Treatment with PP significantly reduced the influx of inflammatory cells in the bronchoalveolar lavage fluid (BALF) and lung of mice with CS- and LPS-induced pulmonary inflammation. PP also decreased the levels of reactive oxygen species (ROS) and pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the BALF. PP effectively attenuated the expression of monocyte chemoattractant protein-1 (MCP-1) and the activation of extracellular signal-regulated kinase (ERK) in the lung. In addition, nuclear factor erythroid 2-related factor 2 (Nrf2) activation and heme oxygenase-1 (HO-1) expression were increased by PP treatment. In an in vitro experiment, PP reduced the mRNA expression of TNF-α and MCP-1, and the activation of ERK in CS extract-stimulated A549 epithelial cells. Furthermore, PP increased the activation of Nrf2 and the expression of HO-1 in A549 cells. These findings suggest that PP has a therapeutic potential for the treatment of pulmonary inflammatory diseases, such as chronic obstructive pulmonary disease.

Ambroxol for the treatment of fibromyalgia: science or fiction?

Fibromyalgia appears to present in subgroups with regard to biological pain induction, with primarily inflammatory, neuropathic/neurodegenerative, sympathetic, oxidative, nitrosative, or muscular factors and/or central sensitization. Recent research has also discussed glial activation or interrupted dopaminergic neurotransmission, as well as increased skin mast cells and mitochondrial dysfunction. Therapy is difficult, and the treatment options used so far mostly just have the potential to address only one of these aspects. As ambroxol addresses all of them in a single substance and furthermore also reduces visceral hypersensitivity, in fibromyalgia existing as irritable bowel syndrome or chronic bladder pain, it should be systematically investigated for this purpose. Encouraged by first clinical observations of two working groups using topical or oral ambroxol for fibromyalgia treatments, the present paper outlines the scientific argument for this approach by looking at each of the aforementioned aspects of this complex disease and summarizes putative modes of action of ambroxol. Nevertheless, at this point the evidence basis for ambroxol is not strong enough for clinical recommendation.

HemoHIM, a herbal preparation, alleviates airway inflammation caused by cigarette smoke and lipopolysaccharide

HemoHIM, herbal preparation has designed for immune system recovery. We investigated the anti-inflammatory effect of HemoHIM on cigarette smoke (CS) and lipopolysaccharide (LPS) induced chronic obstructive pulmonary disease (COPD) mouse model. To induce COPD, C57BL/6 mice were exposed to CS for 1 h per day (eight cigarettes per day) for 4 weeks and intranasally received LPS on day 26. HemoHIM was administrated to mice at a dose of 50 or 100 mg/kg 1h before CS exposure. HemoHIM reduced the inflammatory cell count and levels of tumor necrosis factor receptor (TNF)-α, interleukin (IL)-6 and IL-1β in the broncho-alveolar lavage fluid (BALF) induced by CS+LPS exposure. HemoHIM decreased the inflammatory cell infiltration in the airway and inhibited the expression of iNOS and MMP-9 and phosphorylation of Erk in lung tissue exposed to CS+LPS. In summary, our results indicate that HemoHIM inhibited a reduction in the lung inflammatory response on CS and LPS induced lung inflammation via the Erk pathway. Therefore, we suggest that HemoHIM has the potential to treat pulmonary inflammatory disease such as COPD.

Protective effect of HwangRyunHaeDok-Tang water extract against chronic obstructive pulmonary disease induced by cigarette smoke and lipopolysaccharide in a mouse model

ETHNOPHARMACOLOGICAL RELEVANCE

Hwangryunhaedok-tang is an oriental herbal formula treated to cure inflammation and gastric disorders in China, Japan, and Korea. We explored the protective effects of Hwangryunhaedok-tang water extract (HRWE) against airway pathophysiological changes caused by cigarette smoke (CS) and lipopolysaccharide (LPS) in a mouse.

MATERIALS AND METHODS

We performed quantitative analyses of five marker components, namely geniposide, baicalin, coptisine, plamatine, and berberine, using high-performance liquid chromatography. Animals were received CS exposure (1h per day) for 7 days. LPS was administered intranasally on day 4. Mice were received HRWE at dose of 100 or 200mg/kg for 1h before CS exposure.

RESULTS

Treatment with HRWE significantly suppressed the increased inflammatory cell count induced by CS and LPS exposure. In addition, reduction in IL-6, TNF-α and IL-1β in broncho-alveolar lavage fluid (BALF) was observed after HRWE treatment. HRWE not only decreased inflammatory cell infiltration in lung, but also decreased the expression of iNOS, NF-κB and matrix metallopeptidase (MMP)-9 in lung tissues.

CONCLUSION

This study showed that HRWE can attenuate respiratory inflammation caused by CS and LPS exposure. Therefore, HRWE has potential for treating airway inflammatory disease.

Atomization method for verifying size effects of inhalable particles on lung damage of mice

To explore the size effects of inhalable particles on lung damage, aqueous aerosol containing cadmium was studied as a model to design a new type of two-stage atomization device that was composed of two adjustable parts with electronic ultrasonic atomization and pneumatic atomization. The working parameters and effectiveness of this device were tested with H₂O atomization and CdCl₂ inhalation, respectively. By gravimetrically detecting the mass concentrations of PM_2.5 and PM₁₀ and analysing the particle size with a laser sensor, we confirmed the particle size distribution of the aqueous aerosol produced by the new device under different working conditions. Then, we conducted experiments in male Kunming mice that inhaled CdCl₂ to determine the size effects of inhalable particles on lung damage and to confirm the effectiveness of the device. The new device could effectively control the particle size in the aqueous aerosol. The inhaled CdCl₂ entered and injured the lungs of the mice by causing tissue damage, oxidative stress, increasing endoplasmic reticulum stress and triggering an inflammatory response, which might be related to where the particles deposited. The smaller particles in the aqueous aerosol atomized by the new two-stage atomization device deposited deeper into lung causing more damage. This device could provide a new method for animal experiments involving inhalation with water-soluble toxins.