Unusual cause of an elevated hemidiaphragm: large right-sided spontaneous diaphragmatic hernia induced by severe chronic cough in an adolescent patient with asthma

Improvement of RSV-Induced Asthma in Mice: A Study Based on Icariin-Mediated PD-1

BACKGROUND

Infection with respiratory syncytial virus (RSV) has the potential to exacerbate asthma by causing prolonged inflammation in the airways. Mounting evidence has revealed the significant involvement of programmed cell death protein-1 (PD-1) in the development of asthma. Although icariin (IC) has shown potential in improving airway remodeling in ovalbumin (OVA)-induced asthma, its impact and underlying mechanisms in cases of asthma aggravated by RSV infection are not thoroughly understood.

OBJECTIVE

To explore the effect of IC on RSV-infected asthmatic mice and the mechanism involving PD-1.

METHODS

A model of asthmatic mice infected with RSV was developed. To evaluate the effects of IC treatment, general behavioral characterization, histopathologic analysis, bronchoalveolar lavage fluid (BALF) analysis, and enzyme-linked immunosorbent assays (ELISA) were performed to assess the frequency of sneezing and nose scratching, the content of OVA-specific IgE, oxidative stress and airway inflammation in mice. Apoptosis was also assessed by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL). Finally, the expression levels of apoptosis protein, oxidative stress-related protein, and PD-1 were assessed by western blot.

RESULTS

IC significantly ameliorated the sneezing and nose-scratching frequency (p < 0.001) and decreased OVA-specific IgE levels in asthmatic mice infected with RSV (p < 0.01). IC treatment remarkably reduced the infiltration of inflammatory cells around the alveoli and lowered the overall inflammation score. It also notably decreased the levels of inflammatory cytokines interleukin-4 (IL-4), IL-13, and IL-5, and decreased the numbers of neutrophils, eosinophils, and macrophages in the bronchoalveolar lavage fluid (BALF) (p < 0.001). IC ameliorated oxidative stress in RSV-infected asthmatic mice (p < 0.001). In addition, IC reduced apoptosis while increasing PD-1 expression in asthmatic mice infected with RSV (p < 0.001). Interestingly, si-PD-1 significantly reversed IC inhibition of inflammatory cytokines and apoptosis-related proteins, and promoted PD-1 protein expression (p < 0.01). The findings suggested that IC might be effective in alleviating asthma triggered by RSV in mice by regulating the expression of PD-1.

CONCLUSION

IC ameliorated RSV-induced asthma in mice by regulating PD-1 expression, and may hold promise as a potential therapeutic agent for RSV-induced asthma in mice. These findings provide valuable insights into the possibility of using IC as a treatment option for asthma caused by RSV.

Wuhu Decoction Regulates Dendritic Cell Autophagy in the Treatment of Respiratory Syncytial Virus (RSV)-Induced Mouse Asthma by AMPK/ULK1 Signaling Pathway

BACKGROUND Dendritic cell autophagy plays a pivotal role in asthma. Wuhu decoction can significantly improve respiratory syncytial virus (RSV) bronchiolitis and delay its development into asthma. The aim of the present study was to explore the therapeutic effect and mechanism of Wuhu decoction on RSV -induced asthma in mice. MATERIAL AND METHODS Establishment of asthmatic mice model was induced by RSV. Hematoxylin-eosin staining, periodic acid-Schiff (PAS) staining, and Masson trichrome staining were performed to observe pathological changes in the lungs. The levels of CD4⁺ T, CD8⁺ T, and CD4⁺ CD25⁺ T in blood were analyzed by flow cytometry. The contents of interleukin (IL)-4, interferon-gamma (IFN-γ), IL-10, and IL-13 in serum were measured by enzyme-linked immunosorbent assay (ELISA). The number of autophagosomes in dendritic cells (DCs) of lung tissue was observed by transmission electron microscope. The DCs of lung tissue were isolated by magnetic bead sorting. The levels of LC3-II, Beclin-1, and LC3-I in DCs and MMP-9, TIMP-1, AMPK, p-AMPK, ULK1, and LK1 expression in lung tissues were detected by western blot. Real-time polymerase chain reaction (PCR) detected the expression of AMPK and ULK1 genes. RESULTS Wuhu decoction can effectively alleviate chronic airway inflammation and airway remodeling and reduce airway hyperresponsiveness. Moreover, Wuhu decoction can significantly enhance the level of autophagy in DCs of lung tissue and promote the expression of AMPK and ULK1 in lung tissue. CONCLUSIONS Wuhu decoction may improve the RSV-induced asthmatic symptoms by enhancing autophagy of DCs in lung tissue dependent on the AMPK/ULK1 signaling pathway.