In a healthy human, the airway mucus forms a thin, protective liquid layer covering the surface of the respiratory tract. It comprises a complex blend of mucin, multiple antibacterial proteins, metabolic substances, water, and electrolytes. This mucus plays a pivotal role in the lungs' innate immune system by maintaining airway hydration and capturing airborne particles and pathogens. However, heightened mucus secretion in the airway can compromise ciliary clearance, obstruct the respiratory tract, and increase the risk of pathogen colonization and recurrent infections. Consequently, a thorough exploration of the mechanisms driving excessive airway mucus secretion is crucial for establishing a theoretical foundation for the eventual development of targeted drugs designed to reduce mucus production. Across a range of lung diseases, excessive airway mucus secretion manifests with unique characteristics and regulatory mechanisms, all intricately linked to mucin. This article provides a comprehensive overview of the characteristics and regulatory mechanisms associated with excessive airway mucus secretion in several prevalent lung diseases.
Humans ; Mucus/metabolism* ; Mucins/physiology* ; Lung Diseases/metabolism* ; Respiratory Mucosa/metabolism* ; Pulmonary Disease, Chronic Obstructive/physiopathology* ; Asthma/physiopathology* ; Cystic Fibrosis/physiopathology* ; Mucociliary Clearance/physiology*

OBJECTIVETo investigate the effect of respiratory syncytial virus (RSV)-related pulmonary infection on endogenous metabolites in large intestinal mucosa in BALB/c mice using metabolomics technology based on gas chromatography-mass spectrometry (GC-MS).

METHODSMice were randomly divided into a control group and a RSV pneumonia model group (n=16 each). The mouse model of RSV pneumonia was established using intranasal RSV infection (100×TCID, 50 μL/mouse, once a day). After 7 days of intranasal RSV infection, the mice were sacrificed and GC-MS was used to identify endogenous metabolites and measure the changes in their relative content in colon tissue. SMCA-P12.0 software was used to perform principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) for endogenous metabolites in colon tissue. The differentially expressed metabolites in colon tissue were imported into the metabolic pathway platform Metaboanalyst to analyze related metabolic pathways.

RESULTSPCA and OPLS-DA showed significant differences between the control and RSV pneumonia model groups. A total of 32 metabolites were identified in the colon tissue of the mice with RSV pneumonia. The RSV pneumonia model group had significant increases in the content of leucine, isoleucine, glycine, alanine, arachidonic acid, and lactic acid, which were related to the valine, leucine, isoleucine, arachidonic acid, and pyruvic acid metabolic pathways.

CONCLUSIONSRSV pneumonia might cause metabolic disorders in the large intestinal tissue in mice.

Amino Acids, Branched-Chain ; metabolism ; Animals ; Female ; Gas Chromatography-Mass Spectrometry ; Intestinal Mucosa ; metabolism ; Intestine, Large ; metabolism ; pathology ; Lung ; pathology ; Mice ; Mice, Inbred BALB C ; Pneumonia, Viral ; metabolism ; Respiratory Syncytial Virus Infections ; metabolism

Child ; Humans ; Intestinal Diseases ; metabolism ; physiopathology ; Intestinal Mucosa ; metabolism ; physiopathology ; Intestines ; metabolism ; physiopathology ; Membrane Proteins ; metabolism ; Pediatrics ; Permeability ; Phosphatidylinositol 3-Kinases ; metabolism ; Respiratory Hypersensitivity ; metabolism ; physiopathology ; Tight Junctions ; metabolism ; physiology

No abstract available.
Air Pollutants/*toxicity ; Animals ; Biological Markers/metabolism ; Cell Proliferation/*drug effects ; Female ; Immunohistochemistry ; Inhalation Exposure ; Mice ; Mice, Inbred BALB C ; Nasal Mucosa/drug effects/pathology ; Ozone/*toxicity ; Proliferating Cell Nuclear Antigen/metabolism ; Respiratory Mucosa/*drug effects/metabolism/pathology ; Skin/*drug effects/metabolism/pathology

BACKGROUNDAirway mucus hypersecretion is an important pathophysiological feature of chronic obstructive pulmonary disease, which is closely associated with cigarette smoking. However, the signal transduction pathway from the cell surface to the nucleus through which cigarette smoke causes upregulation of mucin gene expression is not well known. This study was designed to investigate the role of extracellular signal-regulated Kinase 1/2 (ERK 1/2) in airway mucus hypersecretion induced by cigarette smoke in rats.

METHODSA rat model of airway mucus hypersecretion was induced by exposure to cigarette smoke for 4 weeks.Rats exposed to inhalation of cigarette smoke or normal saline were given an intraperitoneal injection of U0126, a specific MEK1 kinase inhibitor, at doses of 0.25 mg/kg, 0.5 mg/kg and 1 mg/kg for 14 days. Expression of MUC5AC mRNA and protein, ERK 1/2 and phosphorylated-ERK 1/2 (p-ERK 1/2) were detected by RT-PCR, immunohistochemistry and Western blotting.

RESULTSCigarette smoke significantly increased airway goblet cells metaplasia, induced the overexpression of MUC5AC mRNA and protein in bronchial epithelia, and increased the ratio of p-ERK 1/2 and ERK 1/2. U0126 significantly attentuated the expression of MUC5AC mRNA and protein induced by cigarette smoke (P < 0.05). Moreover, there was a significant positive correlation between the ratio of p-ERK1/2 to ERK1/2 and the expression of MUC5AC mRNA and protein (P < 0.05).

CONCLUSIONSInhibition of ERK 1/2 by U0126 decreased the ratio of p-ERK 1/2 to ERK 1/2 and expression of MUC5AC mRNA and protein. ERK 1/2 may play an essential role in cigarette smoke-induced mucus hypersecretion in vivo.

Animals ; Blotting, Western ; Bronchi ; cytology ; metabolism ; Goblet Cells ; drug effects ; metabolism ; Immunohistochemistry ; Lung ; drug effects ; metabolism ; Mitogen-Activated Protein Kinase 1 ; genetics ; metabolism ; Mitogen-Activated Protein Kinase 3 ; genetics ; metabolism ; Mucin 5AC ; genetics ; metabolism ; Phosphorylation ; drug effects ; Rats ; Respiratory Mucosa ; secretion ; Reverse Transcriptase Polymerase Chain Reaction ; Smoking ; adverse effects

Sulforaphane (SFN) is a naturally occurring compound which is known to induce the phase II antioxidant genes via Nrf2 activation, although the underlying mechanism has not been fully elucidated. In this study, we investigated Nrf2 induction in response to SFN in human bronchial epithelial BEAS-2B cells and determined the signaling pathways involved in this process. SFN treatment reduced cell viability. Prior to cell death, intracellular reactive oxygen species (ROS) were generated at a high rate within a minute of commencing SFN treatment. Pretreatment with antioxidant N-acetylcysteine (NAC) blocked SFN-induced decrease in cell growth. Erk1/2 was activated within 30 min of SFN addition, whereas Akt phosphorylation did not significantly change until the first 8 hr after SFN treatment but then became substantially low until 48 hr. Inhibition of Erk1/2 phosphorylation attenuated SFN-induced loss of cell viability. Nrf2 protein levels in both nuclear and whole cell lysates were increased by SFN treatment, which was dependent on ROS production. Knockdown of Nrf2 with siRNA attenuated SFN-induced heme oxygenase-1 (HO-1) up-regulation. Induction of the Nrf2/HO-1 after SFN treatment was potently suppressed by pretreatment with NAC. Overall, our results indicate that SFN mediates antioxidative and antiproliferative responses by generating ROS in BEAS-2B cells.
Acetylcysteine/pharmacology ; Anticarcinogenic Agents/pharmacology ; Antioxidants/*pharmacology ; Bronchi/cytology/*drug effects/metabolism ; Cell Line ; Cell Proliferation/*drug effects ; Epithelial Cells/drug effects/metabolism ; Extracellular Signal-Regulated MAP Kinases/metabolism ; Free Radical Scavengers/pharmacology ; Heme Oxygenase-1/biosynthesis ; Humans ; NF-E2-Related Factor 2/biosynthesis/genetics ; Oxidative Stress/drug effects ; Proto-Oncogene Proteins c-akt/metabolism ; RNA Interference ; RNA, Small Interfering ; Reactive Oxygen Species/*metabolism ; Respiratory Mucosa/cytology/*drug effects/metabolism ; Signal Transduction/drug effects ; Thiocyanates/*pharmacology

Scutellarin is a flavonoid extracted from a traditional Chinese herb, Erigeron breviscapus. The present study investigated the effect of scutellarin on MUC5AC mucin production and the possible mechanism. Human bronchial epithelial 16 (HBE16) cells were pretreated with scutellarin for 60 min, and then exposed to human neutrophil elastase (HNE) or interleukin (IL)-13 for 12 hr. RT-PCR and ELISA were performed to measure the amount of MUC5AC mucin production. The results showed that scutellarin inhibited MUC5AC expression both in mRNA and protein level induced by HNE in a concentration-dependent manner. However, scutellarin failed to inhibit MUC5AC mucin production induced by IL-13. To investigate the intracellular mechanisms associated with the effect of scutellarin on MUC5AC mucin production, western blotting was carried out to examine the phosphorylation of protein kinase C (PKC), signal transducer and activator of transcription 6 (STAT6) and extracellular signal-regulated kinase 1/2 (ERK1/2). The phosphorylation of PKC and ERK1/2 was attenuated after treatment with scutellarin, whereas STAT6 was not significantly affected. Therefore, it is suggested that scutellarin down-regulates MUC5AC mucin production on HBE16 cells via ERK-dependent and PKC-dependent pathways.
Apigenin/chemistry/*pharmacology ; Cells, Cultured ; Dose-Response Relationship, Drug ; Down-Regulation ; Epithelial Cells/*drug effects/metabolism ; Erigeron/chemistry ; Glucuronic Acids/chemistry/*pharmacology ; Humans ; Interleukin-13/*pharmacology ; Leukocyte Elastase/*pharmacology ; Mitogen-Activated Protein Kinase 1/metabolism ; Mitogen-Activated Protein Kinase 3/metabolism ; Mucin 5AC/genetics/*metabolism ; Phosphorylation ; Protein Kinase C/metabolism ; Respiratory Mucosa/drug effects/*metabolism ; STAT6 Transcription Factor/metabolism ; Signal Transduction

Hyperoxic ventilation induces detrimental effects on the respiratory system, and ambient oxygen may be harmful unless compensated by physiological anti-oxidants, such as vitamin C. Here we investigate the changes in electrolyte transport of airway epithelium in mice exposed to normobaric hyperoxia and in gulonolacton oxidase knock-out (gulo[-/-]) mice without vitamin C (Vit-C) supplementation. Short-circuit current (Isc) of tracheal epithelium was measured using Ussing chamber technique. After confirming amiloride-sensitive Na+ absorption (DeltaIsc,amil), cAMP-dependent Cl- secretion (DeltaIsc,forsk) was induced by forskolin. To evaluate Ca2+-dependent Cl- secretion, ATP was applied to the luminal side (DeltaIsc,ATP). In mice exposed to 98% PO2 for 36 hr, DeltaIsc,forsk decreased, DeltaIsc,amil and DeltaIsc,ATP was not affected. In gulo(-/-) mice, both DeltaIsc,forsk and DeltaIsc,ATP decreased from three weeks after Vit-C deprivation, while both were unchanged with Vit-C supplementation. At the fourth week, tissue resistance and all electrolyte transport activities were decreased. An immunofluorescence study showed that the expression of cystic fibrosis conductance regulator (CFTR) was decreased in gulo(-/-) mice, whereas the expression of KCNQ1 K+ channel was preserved. Taken together, the CFTR-mediated Cl- secretion of airway epithelium is susceptible to oxidative stress, which suggests that supplementation of the antioxidant might be beneficial for the maintenance of airway surface liquid.
Animals ; Ascorbic Acid Deficiency/*metabolism ; Biological Transport/drug effects ; Chlorides/*metabolism ; Cystic Fibrosis Transmembrane Conductance Regulator/antagonists & inhibitors/drug ; Forskolin/pharmacology ; Hyperbaric Oxygenation ; Hyperoxia/*physiopathology ; Ion Transport/drug effects ; Mice ; Mice, Inbred C57BL ; Mice, Inbred ICR ; Mice, Knockout/metabolism ; Mice, Transgenic ; Microscopy, Fluorescence ; Oxidative Stress ; Oxygen/adverse effects/pharmacology ; Potassium Channels/metabolism ; Respiratory Mucosa/drug effects/*metabolism/secretion ; Sodium ; Sugar Acids/metabolism

OBJECTIVE: To study the expression of epidermal growth factor receptor (EGFR), C-erbB-2 and its relationship with cell proliferation in nasopharyngeal carcinoma. METHOD: Expression of C-erbB-2, EGFR and proliferating cell nuclear antigen (PCNA) were detected with immunohistochemical staining in 32 nasopharyngeal carcinoma samples and 12 chronic inflammatory nasopharyngeal tissue samples. RESULT: The positive rate of EGFR,C-erbB-2, and PCNA expression in nasopharyngeal carcinoma was 65.6%, 37.5%, and (42.5 +/- 22.6)%, respectively, which was significantly higher than that in chronic inflammatory nasopharyngeal tissue (P < 0.05). There were positive correlations between the positive rate of EGFR, C-erbB-2, and PCNA expression and histopathological stage. The co-expression of C-erbB2 and EGFR was found in 62.5% (20/32) nasopharyngeal carcinoma samples. There was a positive correlation between C-erbB-2 and EGFR expression (r = 0.38, P < 0.05). The highest percentage of PCNA expression was found in carcinoma samples with co-expression of C-erbB and EGFR. CONCLUSION C-erbB-2, EGFR might have synergetic effect in the development and progress of nasopharyngeal carcinoma. The co-expression of C-erbB-2 and EGFR closely correlates with cell proliferation status.
Adult ; Aged ; Aged, 80 and over ; Carcinoma, Squamous Cell ; metabolism ; pathology ; Cell Proliferation ; ErbB Receptors ; metabolism ; Female ; Humans ; Male ; Middle Aged ; Nasopharyngeal Neoplasms ; metabolism ; pathology ; Proliferating Cell Nuclear Antigen ; metabolism ; Receptor, ErbB-2 ; metabolism ; Respiratory Mucosa ; metabolism ; Young Adult

OBJECTIVETo study the alternative expression and sequence of human elongation factor-1 delta (human EF-1 delta p31) during malignant transformation of human bronchial epithelial cells induced by cadmium chloride (CdC12) and its possible mechanism.

METHODSTotal RNA was isolated at different stages of transformed human bronchial epithelial cells (16HBE) induced by CdCl2 at a concentration of 5.0 microM. Special primers and probe for human EF-1 delta p31 were designed and expression of human EF-1 delta mRNA from different cell lines was detected with fluorescent quantitative PCR technique. EF-18 cDNA from different cell lines was purified and cloned into pMD 18-T vector followed by confirming and sequencing analysis.

RESULTSThe expressions of human EF-1 beta p31 at different stages of 16HBE cells transformed by CdCl2 was elevated (P < 0.01 or P < 0.05). Compared with their corresponding non-transformed cells, the overexpression level of EF-1 delta p31 was averagely increased 2.9 folds in Cd-pretransformed cells, 4.3 folds in Cd-transformed cells and 7.2 folds in Cd-tumorigenic cells. No change was found n the sequence of overexpressed EF-1beta p31 at different stages of 16HBE cells transformed by CdCl2.

CONCLUSIONOverexpression of human EF-1beta p31 is positively correlated with malignant transformation of 16HBE cells induced by CdC12, but is not correlated with DNA mutations.

Cadmium Chloride ; Cell Line ; Cell Transformation, Neoplastic ; chemically induced ; metabolism ; Epithelial Cells ; drug effects ; metabolism ; pathology ; Gene Expression Regulation, Neoplastic ; Humans ; Peptide Elongation Factor 1 ; genetics ; metabolism ; Respiratory Mucosa ; drug effects ; metabolism ; pathology ; Sequence Analysis, DNA