ISU201 enhances the resolution of airway inflammation in a mouse model of an acute exacerbation of asthma

Increased MMP12 mRNA expression in induced sputum was correlated with airway eosinophilic inflammation in asthma patients: evidence from bioinformatic analysis and experiment verification

BACKGROUND

Asthma is a common chronic airway inflammatory disease worldwide. Studies on gene expression profiles in induced sputum may provide noninvasive diagnostic biomarkers and therapeutic targets for asthma.

OBJECTIVE

To investigate mRNA expression of MMP12 in induced sputum and its relationship with asthma airway eosinophilic inflammation.

METHODS

GSE76262 dataset was analyzed using R software, weighted gene coexpression network analysis (WGCNA), and protein-protein interaction (PPI) network construction. The top ten hub genes were screened with Cytoscape software (version 3.8.4). We then verified the mRNA expression of MMP12 in two other datasets (GSE137268 and GSE74075) via ROC curve estimates and our induced sputum samples using real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). Finally, we explored the correlation between MMP12 with asthmatic eosinophilic-related indicators.

RESULTS

We obtained the top ten hub genes, namely, CCL17, CCL2, CSF1, CCL22, CCR3, CD69, FCGR2B, CD1C, CD1E, and MMP12 via expression profile screening and validation on the GSE76262 dataset. MMP12 was selected as the candidate gene through further validation on GSE137268 and GSE74075 datasets. Finally, we demonstrated that the mRNA expression of MMP12 is significantly upregulated in induced sputum of asthmatic patients (p<0.05) and significantly correlated with eosinophilic-related indicators (p<0.05). These findings indicated that MMP12 can act as a diagnostic biomarker for asthma.

CONCLUSION

Our study successfully identified and demonstrated that MMP12 is a potential diagnostic biomarker for asthma due to its high expression and association with eosinophilic-related indicators. The results of this study can provide novel insights into asthmatic diagnosis and therapy in the future.

Screening of Sceptridium ternatum for antitussive and antiasthmatic activity and associated mechanisms

Objectives

Sceptridium ternatum is an expectorant in traditional Chinese medicine and is prescribed for the treatment of asthma. The study aim was to screen Sceptridium ternatum for ingredients with antitussive and antiasthmatic effects and to study their associated mechanisms.

Methods

Cough in mice was induced using ammonia. Cough latency and the number of coughs within 3 minutes were determined. Airway responsiveness was assessed using ovalbumin as a sensitizer and characteristic asthma indicators were measured.

Results

Chloroform and ethyl acetate extracts significantly reduced the number of coughs within 3 minutes, tidal volume, and the percentage of eosinophilic granulocytes, lymphocytes and neutrophils. All extracts decreased airway responsiveness in asthmatic mice compared with the untreated group. Petroleum ether, chloroform and n-butanol extracts lowered the Penh values of asthmatic mice. Petroleum ether and ethyl acetate extracts greatly reduced interleukin-4 expression and the interleukin-4/interferon gamma ratio. Compared with the model group, all extracts reduced mRNA expression of the cysteinyl leukotriene receptor-1 (CysLT₁).

Conclusions

Chloroform extract and ethyl acetate extract displayed obvious antitussive effects and reduced airway inflammation. Thus, these two extracts contain the effective ingredients of Sceptridium ternatum. The active mechanism was ascribed to inhibition of mRNA expression of the CysLT₁ receptor in mice with bronchial asthma.

Mouse models of acute exacerbations of allergic asthma

Most of the healthcare costs associated with asthma relate to emergency department visits and hospitalizations because of acute exacerbations of underlying chronic disease. Development of appropriate animal models of acute exacerbations of asthma is a necessary prerequisite for understanding pathophysiological mechanisms and assessing potential novel therapeutic approaches. Most such models have been developed using mice. Relatively few mouse models attempt to simulate the acute-on-chronic disease that characterizes human asthma exacerbations. Instead, many reported models involve relatively short-term challenge with an antigen to which animals are sensitized, followed closely by an unrelated triggering agent, so are better described as models of potentiation of acute allergic inflammation. Triggers for experimental models of asthma exacerbations include (i) challenge with high levels of the sensitizing allergen (ii) infection by viruses or fungi, or challenge with components of these microorganisms (iii) exposure to environmental pollutants. In this review, we examine the strengths and weaknesses of published mouse models, their application for investigation of novel treatments and potential future developments.