Pathogenesis of Airway Mucus Hypersecretion in Chronic Obstructive Pulmonary Disease and Intervention of Traditional Chinese Medicine： A Review / 中国实验方剂学杂志

Chronic obstructive pulmonary disease （COPD） is one of the most common chronic diseases of the respiratory system in the clinic. The disease has a long course and is difficult to cure， which seriously threatens human health. Airway mucus hypersecretion （AMH） is an independent risk factor for COPD and has a significant impact on the development and prognosis of the disease. The review finds that the abnormal proliferation of goblet cells and the excessive secretion of mucin are the direct causes of AMH. The pathogenesis of AMH may be closely related to the inhalation of heterogeneous particles， airway inflammation， the imbalance of mucin/water salt ratio， and the regulation of related signaling pathways. Traditional Chinese medicine （TCM） believes that AMH of COPD belongs to the category of lung distension with phlegm-fluid retention syndrome， and the disease is mainly treated from phlegm on the basis of lung distension. This article summarizes the relevant research in the field of TCM in recent years and finds that the single TCM that effectively intervened AMH of COPD is mainly phlegm-resolving TCM， and the main active ingredients of TCM are flavonoids， terpenoids， phenols， and alkaloids. The main TCM compounds are mainly designed to remove heat-phlegm， warmly resolve cold-phlegm， dry dampness to eliminate phlegm， invigorate Qi， promote blood circulation and dispel phlegm， and invigorate lung， spleen， and kidney. Its mechanism of action may be direct inhibition or indirect inhibition of airway epithelial goblet cell metaplasia and mucin expression by inhibiting airway inflammation， regulating aquaporins to correct the imbalance of mucin/water salt ratio， and regulating signaling pathways， so as to reduce mucus oversecretion in COPD. However， there are still some problems. For example， the research mainly focuses on TCM compounds instead of the single TCM or its effective components. The research on the mechanism of action is not thorough enough， and the research results are not interoperable. The clinical transformation rate of basic research is insufficient. This article systematically reviews the research status of AMH in the treatment of COPD with TCM and puts forward some thoughts on the existing problems， so as to provide a reference for clinical rational medication and in-depth research.

Effective-compound combination of Bufei Yishen formula III combined with ER suppress airway mucus hypersecretion in COPD rats: via EGFR/MAPK signaling.

BACKGROUND: The aim of this study was to explore the combined efficacy ofeffective-component compatibility of Bufei Yishen formula III (ECC-BYF III) and exercise rehabilitation (ER) in inhibiting airway mucus hypersecretion in a chronic obstructive pulmonary disease (COPD) rat model. METHODS: A total of 48 SD rats were divided into control, model, acetylcysteine (NAC), ECC-BYF III, ER, and ECC-BYF III + ER groups (n=8). COPD rats were exposed to cigarette smoke and bacteria for 8 weeks and administered various treatments over the next eight weeks. Rats were euthanized at week 17 after pulmonary function testing. Pathological examination of lung tissues was performed. IL-6 and IL-10 levels were measured in bronchoalveolar lavage fluid (BALF) and protein levels of MUC5AC, MUC5B, AQP-5, EGFR, ERK, JNK, and p38 were measured in lung tissues. RESULTS: Improved pulmonary function and pathological changes were observed in ECC-BYF III, ECC-BYF III + ER, and NAC groups. ECC-BYF III and ECC-BYF III + ER had greater mean alveolar number (MAN) compared with NAC. Lung inflammation and goblet cell generation were reduced and MUC5AC, MUC5B and AQP-5 expressions were lower in all treatment groups. ECC-BYF III has more significant effect on MUC5AC than ER and NAC. ECC-BYFIII + ER had a greater effect on suppressing IL-6 in BALF compared with other treatments. ECC-BYFIII, ER, and ECC-BYF III + ER reduced EGFR, ERK, JNK, and p38 phosphorylated protein levels. ECC-BYFIII+ER had a greater effect on p-JNK and p-p38 than ECC-BYFIII and NAC. CONCLUSION: ECC-BYF III, ER, and ECC-BYF III + ER have efficacy in inhibiting airway mucus hypersecretion with improved pulmonary function and pathological changes. ECC-BYF III had a greater effect in improving MAN and MUC5AC in lung tissue. ECC-BYF III+ER had a greater effect in alleviating pulmonary pathology and inflammation. These effects may be mediated by inhibition of the EGFR/MAPK pathway.

Interleukin-6 neutralizing antibody attenuates the hypersecretion of airway mucus via inducing the nuclear translocation of Nrf2 in chronic obstructive pulmonary disease.

Airway mucus hypersecretion is a vital pathophysiologic feature in chronic obstructive pulmonary disease (COPD) patients in which airflow limitation result, and it is key to strategizing in the management of COPD. To investigate the mechanisms underlying the action of interleukin-6 neutralizing antibody (IL-6 Ab) in attenuating airway mucus hypersecretion in COPD, human and mouse primary bronchial epithelial cells from COPD patients and mice were isolated, human organoid model of trachea was established and all treated with IL-6 and/or IL-6 Ab. The differential expression of Muc5ac and Nrf2 were determined in pDHBE compared to pNHBE cells via high-throughput sequencing of transcriptome. The serum concentration of Muc5ac was significantly elevated and positively correlated with IL-6 in COPD patients using ELISA, and the excessive mucus secretion was observed in the trachea of COPD patients using HE, AB-PAS and IHC staining. The levels of Muc5ac were significantly elevated in the IL-6-treated group, and diminished with IL-6 Ab treatment, both in vitro and in the organoid model using qRT-PCR, WB and IF. The expression levels of protein Muc5ac were significantly reduced in cells transfected with the IL-6 small interfering RNA (siRNA-IL-6), which was in contrast to the levels of protein Nrf2, and the protective effects of IL-6 Ab were inhibited in cells transfected with Nrf2 short hairpin RNA (shRNA-Nrf2). IL-6 Ab significantly attenuated hypersecretion of airway mucus by inducing nuclear translocation of Nrf2 in COPD. These findings indicated that IL-6 Ab may constitute a novel therapeutic agent for IL-6-induced airway mucus hypersecretion by improving airflow limitation in COPD patients.

Effect of Bufei Yishen Prescription on Airway Mucus Hypersecretion and Notch3 and HES1 Expression in Lung Tissues of Rats with Chronic Obstructive Pulmonary Disease / 中国实验方剂学杂志

ObjectiveTo observe the effects of Bufei Yishen prescription on airway mucus hypersecretion and Notch signaling pathway related protein Notch3 and enhancer of split homologue 1 （HES1） in rats with chronic obstructive pulmonary disease （COPD） and to explore its action mechanism. MethodForty-eight SD rats were randomly divided into the control group， model group， Bufei Yishen prescription group， and aminophylline （APL） group，with 12 rats in each group. The stable COPD rat model was established via cigarette smoking exposure combined with Klebsiella bacterial infection for 12 weeks， and the corresponding drugs （3.7 g·kg-1·d-1 Bufei Yishen prescription and 54 mg·kg-1·d-1 APL） were administered by gavage during the next eight weeks. After the last administration at week 20， the lung tissue was sampled for observing the pathological changes and the rat lung function was detected. The tumor necrosis factor-α （TNF-α）， interleukin-6 （IL-6）， and mucoprotein 5AC （MUC5AC） in bronchial alveolar lavage fluid and the mRNA and protein expression levels of Notch3， HES1， and MUC5AC in lung tissues were assayed. ResultCompared with the control group， the model group exhibited significantly weakened pulmonary function （P<0.05，P<0.01）， reduced average number of alveoli （P<0.01）， elevated mean linear intercept （P<0.01）， and up-regulated TNF-α， IL-6， and MUC5AC in bronchial alveolar lavage fluid and Notch3， HES1， and MUC5AC mRNA and protein expression in lung tissue （P<0.05，P<0.01）. Compared with the model group， Bufei Yishen prescription and APL remarkably enhanced pulmonary function， alleviated its pathological injury （P<0.05，P<0.01）， and down-regulated TNF-α， IL-6， and MUC5AC in bronchial alveolar lavage fluid and the mRNA and protein expression levels of Notch3， HES1， and MUC5AC in lung tissues （P<0.05，P<0.01）. ConclusionThe mechanism of Bufei Yishen prescription in inhibiting airway mucus hypersecretion of COPD rats was related to its regulation of Notch3 and HES1.

Influence of coexistence of mild OSA on airway mucus hypersecretion in patients with COPD.

The coexistence of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) can cause multiple system damage, and the main physiological mechanisms are continuous hypoxia and intermittent hypoxia (IH). Airway mucus hypersecretion is an important clinical feature of COPD, which can cause a progressive decline of lung function, acute COPD aggravation, and disease progression. The purpose of our study is to determine the influence of the coexistence of mild OSA on airway mucus hypersecretion. Clinical data and airway epithelial samples of 36 subjects were collected. The average fluorescence intensity of MUC5AC and the number of goblet cells were measured through immunofluorescence staining. MUC5AC expression was measured in human bronchial epithelial (HBE) cells exposed to normoxia, IH, particulate matter (PM), and PM + IH using real-time quantitative polymerase chain reaction and western blotting. FEV1% pred and FEV1/FVC were higher in patients with COPD-OSA overlap syndrome (OS) than in patients with COPD alone. Patients with OS had less sputum volume than patients with COPD alone. MUC5AC expression and the number of goblet cells in the airway epithelium in the COPD alone group were significantly higher than those in the OS groups. The PM + IH group had lower MUC5AC mRNA and protein expression in HBE cells than the PM group. The coexistence of mild OSA may reduce goblet cell proliferation and MUC5AC expression in the airway epithelium of patients with COPD. Mild IH inhibited PM-induced up-regulation of MUC5AC expression in the mRNA and protein levels in HBE cells.

Experimental study of the effects of Yunpi-Xiefei-Huatan Decoction on the expression of EGFR and MUC5AC in lung tissue of asthmatic rat model / 国际中医中药杂志

Objective:To observe the effect of Yunpi-Xiefei-Huatan Decoction on airway mucus hypersecretion of asthmatic rats and its regulation on epidermal growth factor receptor (EGFR) / mucin 5AC (MUC5AC) signal pathway. Methods:Seventy SD rats were randomly divided into normal group, model group, high dose group, medium dose group, low dose group, western medicine group and combined group, with 10 rats in each group. Except the normal group, the other groups were sensitized with 1 ml ovalbumin and aluminum hydroxide mixture to establish the asthma rat model. On the 16th day of the experiment, the high, medium and low dose groups were given Yunpi-Xiefei-Huatan Decoction of 40, 20, 10 g/kg, respectively, the western medicine group was given carboxymethylstein tablets of 150 mg/kg, and the combined group was given Yunpi-Xiefei-Huatan Decoction of 20 g/kg and carboxymethylstein tablets of 150 mg/kg, once a day, for 4 weeks. The levels of tumor necrosis factor (TNF-α) and interleukin-13 (IL-13) in serum of rats were detected by Enzyme-linked Immunosorbent Assay (ELISA), the total number and classification of leukocytes in BALF were observed by Wright Giemsa staining, the pathological changes of lung tissue were observed by glycogen staining (PAS). The protein expression of epidermal growth factor receptor (EGFR) and MUC5AC (MUC5AC) were detected by Western blotting, and the mRNA expression of EGFR and MUC5AC was detected by Reverse Transcriptase Polymerase Chain Reaction (RT-PCR). Results:Compared with the model group, the level of IL-13 and TNF-α in the high, medium and low dose groups of traditional Chinese medicine, western medicine group and combined group was significantly decreased ( P<0.05). The levels of WBC, eosinophils and neutrophils in rat alveolar lavage fluid were significantly decreased ( P<0.05). The expression of EGFR (0.466 ± 0.023, 0.354 ± 0.047, 0.667 ± 0.066, 0.553 ± 0.065, 0.290 ± 0.033 vs. 0.782 ± 0.047) and MUC5AC (0.424 ± 0.022, 0.313 ± 0.033, 0.603 ± 0.051, 0.495 ± 0.041, 0.243 ± 0.024 vs. 0.806 ± 0.090) significantly decreased ( P<0.05), the m RNA expression of EGFR (2.302 ± 0.321, 2.549 ± 0.623, 3.084 ± 0.453, 2.585 ± 0.314, 1.810 ± 0.379 vs. 4.101 ± 0.567), MUC5AC (3.243 ± 0.742, 3.283 ± 1.064, 4.419 ± 0.572, 3.817 ± 0.637, 2.469 ± 0.424 vs. 5.840 ± 0.661) in the high, medium and low dose groups, western medicine group and combined group was significantly decreased ( P<0.05). Conclusion:Yunpi-Xiefei-Huatan Decoction ccould inhibit asthma, and its mechanism mightbe related to the EGFR/MUC5AC signaling pathway.

The Potential Role and Regulatory Mechanisms of MUC5AC in Chronic Obstructive Pulmonary Disease.

Chronic obstructive pulmonary disease (COPD) is associated with high morbidity and mortality globally. Studies show that airway mucus hypersecretion strongly compromises lung function, leading to frequent hospitalization and mortality, highlighting an urgent need for effective COPD treatments. MUC5AC is known to contribute to severe muco-obstructive lung diseases, worsening COPD pathogenesis. Various pathways are implicated in the aberrant MUC5AC production and secretion MUC5AC. These include signaling pathways associated with mucus-secreting cell differentiation [nuclear factor-κB (NF-κB)and IL-13-STAT6- SAM pointed domain containing E26 transformation-specific transcription factor (SPDEF), as well as epithelial sodium channel (ENaC) and cystic fibrosis transmembrane conductance regulator (CFTR)], and signaling pathways related to mucus transport and excretion-ciliary beat frequency (CBF). Various inhibitors of mucus hypersecretion are in clinical use but have had limited benefits against COPD. Thus, novel therapies targeting airway mucus hypersecretion should be developed for effective management of muco-obstructive lung disease. Here, we systematically review the mechanisms and pathogenesis of airway mucus hypersecretion, with emphasis on multi-target and multi-link intervention strategies for the elucidation of novel inhibitors of airway mucus hypersecretion.

Eucalyptol protects lungs against bacterial invasion through attenuating ciliated cell damage and suppressing MUC5AC expression.

This study was conducted to investigate whether eucalyptol plays a role in influencing bacterial growth in cigarette smoke-exposed lungs. Rats were exposed to air (control) and cigarette smoke (smoking) in the presence and absence of eucalyptol (260 mg/day). Morphological analysis of lung structures and status of airway mucous production were observed under microscope. Pathological changes of ciliated columnar epithelium in airways were examined using transmission electron microscopy. MUC5AC protein and messenger RNA (mRNA) expression in bronchoalveolar lavage fluid (BALF) and lungs were determined. Application of eucalyptol reduced pulmonary bullae formation and airway mucus overproduction in the smoke-exposed lungs. Treatment with eucalyptol attenuated ciliated cell damage in cigarette smoke-exposed lungs. Bacterial colonies of lungs were obviously lower in the eucalyptol-treated rats than that in the smoking rats (p < 0.01). Treatment with eucalyptol reduced the counts of bacterial colonization residing in the challenged lungs (p < 0.01). Application of eucalyptol not only decreased MUC5AC protein expression in BALF and tobacco-exposed lungs but also suppressed its mRNA expression in the lungs (all p < 0.05). Intervention of eucalyptol benefits elimination of bacterial organisms from tobacco-exposed lungs through attenuating ciliated cell damage and suppressing MUC5AC expression in the lungs.

[Brahma-related gene 1 promotes airway mucus hypersecretion via STAT6 in asthmatic mice].

OBJECTIVE: To investigate the effect of Brahma-related gene 1 (Brg1) on mucus hypersecretion in the airway of asthmatic mice and explore the mechanism. METHODS: Female C57bl/6 mice aged 6-8 weeks were randomized into wild-type control group, wild-type asthma group, Brg1-/- group with Brg1 gene knockdown in type Ⅱ alveolar epithelial cells, and Brg1-/-+ asthma group (n=10). The mice in asthma group and Brg1-/-+asthma group were sensitized with ovalbumin (OVA) to establish asthmatic models. PAS staining was used to determine the number of goblet cells and mucus secretion in the airway. Real-time PCR was used to detect the expression of MUC5AC mRNA in the lung tissues. The levels of mucin MUC5AC and interleukin-13 (IL-13) in the bronchoalveolar lavage fluid (BALF) were detected with ELISA and immunohistochemistry, and the expressions of STAT6 and p-STAT6 in the lung tissue were detected using Western blotting. RESULTS: Compared with the control mice, wild-type asthmatic mice showed obvious mucus hypersecretion and increased MUC5AC mRNA in the airway with significantly increased IL-13 and MUC5AC levels in the BALF and activation of p-STAT6 in the lung tissues (P < 0.05). In the transgenic mice with Brg1 gene knockdown, airway mucus secretion and MUC5AC mRNA expression was significantly reduced following OVA challenge compared with those in the wild-type asthmatic mice; IL-13 and MUC5AC levels in the BALF and p-STAT6 expression in the lung tissues were also significantly decreased in the transgenic mice (P < 0.05). CONCLUSIONS: Brg1 gene knockdown in type Ⅱ alveolar epithelial cells alleviates OVA-induced airway mucus hypersecretion and reduces the expression of MUC5AC in C57bl/6 mice possibly by inhibiting STAT6 activation, suggesting the role of Brg1 in promoting asthmatic airway mucus hypersecretion.

Effects of Qingjin Huatan Decoction on EGFR/MAPK Signaling Pathway of Airway Mucus Hypersecretion Rats with Chronic Obstructive Pulmonary Disease / 中国中医药信息杂志

Objective To observe the effects of Qingjin Huatan Decoction on EGFR/MAPK signaling pathway of airway mucus hypersecretion rats with chronic obstructive pulmonary disease (COPD). Methods Intratracheal instillation of LPS combined with smudging method was used to establish COPD airway mucus hypersecretion rat models. Experimental rats were randomly divided into blank group, model group, Qingjin Huatan Decoction group and clarithromycin group. The blank group was normally fed, while the other three groups were given NS, Qingjin Huatan Decoction, and clarithromycin respectively for gavage, once a day for 30 days. All rats were killed on the 31st day, and pathological changes of lung tissue and mucous glands hyperplasia were observed by HE staining method. The gene expressions of EGFR and MUC5AC in lung tissue were detected by RT-PCR method. The protein expressions of P-EGFR, P-ERK, P-JNK, P-p38 and MUC5AC in pulmonary tissue and airway epithelium were detected by immunohistochemical method. Results Compared with the blank group, mucous glands hyperplasia on airway epithelium, protein expressions of P-EGFR, P-ERK, P-JNK, P-p38 and MUC5AC on airway epithelium significantly increased in the model group (P<0.01); gene expression of MUC5AC of lung tissue increased (P<0.05). Compared with the model group, mucous glands hyperplasia on airway epithelium, P-p38, P-ERK and MUC5AC protein expression on airway epithelium in Qingjin Huatan Decoction group significantly decreased (P<0.05, P<0.01); the protein expression of P-JNK increased significantly (P<0.01). EGFR and MUC5AC mRNA in lung tissue in Qingjin Huatan Decoction group decreased significantly (P<0.01). Conclusion Qingjin Huatan Decoction can reduce airway mucus hepersecrection of COPD by inhibiting ERK and p38 signal pathway on EGFR downstream.

Effects ofJiedu QingfeiMixture on Expressions of NE and MUC5AC in Lung Tissue of Rats with Chronic Obstructive Pulmonary Disease / 中国中医药信息杂志

Objective To explore the mechanism ofJiedu Qingfei Mixture for airway mucus hypersecretion of rat models with chronic obstructive pulmonary disease (COPD).Methods Airway instilling lipopolysaccharide combining fuming method was used to establish COPD models. Forty clean level Wistar strain rats were randomly divided into blank control group, model group,Jiedu Qingfei group, and clarithromycin group. Model group, Jiedu Qingfei group, and clarithromycin group were given normal saline,Jiedu Qingfei Mixture, and clarithromycin by gavage respectively, while the blank control group was raised normally for 30 d. All rats were killed on the 31st day for taking lung tissue (6 rats from each group were chosen randomly). Pathological changes of lung tissue and mucous glands hyperplasia were observed by HE staining method. NE and MUC5AC mRNA expression on lung tissue were detected by RT-PCR method. Protein expressions of NE and MUC5AC on pulmonary tissue and airway epithelium were detected by immunohistochemical method.Results Compared with blank control group, mucous glands hyperplasia on airway epithelium, mRNA expression of NE and MUC5AC in lung tissue, and protein expressions of NE and MUCA5C on airway epithelium in the model group significantly increased (P<0.05,P<0.01). Compared with model group, mucous glands hyperplasia on airway epithelium inJiedu Qingfei group significantly decreased (P<0.01), as same as clarithromycin group;Jiedu Qingfei group showed better effects on down-regulating NE and MUC5AC mRNA expression in lung tissue compared with clarithromycin group. MUC5AC protein expression on airway epithelium inJiedu Qingfei group significantly decreased (P<0.05), as same as clarithromycin group.Jiedu Qingfei group and clarithromycin group had no difference on NE protein expression in airway epithelium compared with model group.Conclusion Jiedu Qingfei group Mixture can reduce airway mucus hypersecretion of COPD by down-regulating MUC5AC expression through neutrophil elastase.

Clinical application of expectorant therapy in chronic inflammatory airway diseases (Review).

Airway mucus hypersecretion is a significant clinical and pathological feature of chronic inflammatory airway diseases. Its clinical presentations include recurrent coughing and phlegm. Airway mucus is closely associated with the occurrence, development and prognosis of chronic inflammatory airway diseases and critically affects the lung function, quality of life, hospitalization rate and mortality of patients with chronic inflammatory airway diseases. Therefore, expectorant therapies targeting the potential mechanisms of mucus hypersecretion have been the focus of numerous studies. Conventional expectorants are mainly mucoactive medicines, including nausea-stimulating expectorants, mucolytics, mucokinetics, and proteases and nucleases. In addition, certain traditional Chinese herbal medicines and non-mucoactive agents, including muscarinic acetylcholine receptor antagonists, corticosteroids, leukotriene receptor antagonists and macrolide antibiotics, have also shown expectorant effects. Several novel medicines for expectorant therapy have emerged, including cholesterol-lowering statins, epidermal growth factor receptor tyrosine kinase inhibitors, phosphodiesterase-4 inhibitors, stanozolol, surfactants, flavonoids, tachykinin receptor antagonists, protease inhibitors, cytokine antagonists and purinergic agonists. With the increasing number of multidisciplinary studies, the effectiveness of expectorant therapy for the treatment of chronic inflammatory airway diseases has been confirmed. Therefore, the development of novel expectorants and the standardization of expectorant therapy are the direction and focus of future studies, thus benefiting patients who have a chronic inflammatory airway disease.