RESUMEN
PURPOSE: The mechanisms of CC chemokine receptor 5 (CCR5) in the process of autophagy remain unknown. In this study, we examined the role of HY peptide, which is an antagonistic peptide specifically binding the second extracellular loop of CCR5, in the expression of autophagy genes and ß-arrestin 2 in lung tissues of asthmatic mice. METHODS: Experimental asthmatic mice were treated with HY peptide and dexamethasone sodium phosphate (Dex). Airway inflammation, autophagy-related genes, autophagic vacuoles (AVs) and ß-arrestin 2 were examined in lung tissues, and the correlation between ß-arrestin 2 and LC3 expression was assessed. RESULTS: HY peptide and Dex treatments alleviate airway inflammation. The expression of autophagy-related genes, such as BECN1, ATG5 and LC3, was decreased in the lung tissues of the asthmatic mice. However, HY peptide and Dex treatments increased the expression of these genes as well as the formation of AVs. Additionally, the expression of the ß-arrestin 2 protein was significantly increased in the HY peptide-treated group, and positive cells expressing ß-arrestin 2 were mainly located in the membrane and cytoplasm of bronchial epithelial cells. The ß-arrestin 2 expression was positively correlated with the expression of LC3 in the model and HY peptide-treated groups. CONCLUSIONS: HY peptide inhibits airway inflammation, autophagic dysfunction exists in asthmatic mice, and targeting HY peptide increases the expression of autophagy-related genes. Thus, ß-arrestin 2 may participate in the mechanisms underlying these processes.
RESUMEN
Asthma is a heterogeneous chronic inflammatory disorder of the airways with a complex etiology, which involves a variety of cells and cellular components. Therefore, the aim of the study was to investigate the effects and mechanisms of antagonistic peptides that specifically bind to the first and second extracellular loops of CCR5 (GH and HY peptides, respectively) and anti-interleukin-23 subunit p19 (anti-IL-23p19) in the airway and thereby mediate inflammation and the IL-23/T helper 17 (Th17) cell pathway in asthmatic mice. An experimental asthma model using BALB/c mice was induced by ovalbumin (OVA) and treated with peptides that are antagonistic to CCR5 or with anti-IL-23p19. The extents of the asthmatic inflammation and mucus production were assessed. In addition, bronchoalveolar lavage fluid (BALF) was collected, the cells were counted, and the IL-4 level was detected by ELISA. The IL-23/Th17 pathway-related protein and mRNA levels in the lung tissues were measured, and the positive production rates of Th17 cells in the thymus, spleen, and peripheral blood were detected. The groups treated with one of the two peptides and/or anti-IL-23p19 showed significant reductions in allergic inflammation and mucus secretion; decreased expression levels of IL-23p19, IL-23R, IL-17A and lactoferrin (LTF); and reduced proportions of Th17 cells in the thymus, spleen, and peripheral blood. Specifically, among the four treatment groups, the anti-IL-23p19 with HY peptide group exhibited the lowest positive production rate of Th17 cells. Our data also showed a significant and positive correlation between CCR5 and IL-23p19 protein expression. These findings suggest that the administration of peptides antagonistic to CCR5 and/or anti-IL-23p19 can reduce airway inflammation in asthmatic mice, most likely through inhibition of the IL-23/Th17 signaling pathway, and the HY peptide can alleviate inflammation not only through the IL-23/Th17 pathway but also through other mechanisms that result in the regulation of inflammation.