C Terminatio Peptide C19/C27 Of Chemokine-like Factor1(CKLF1) Effect On The Airway Inflammation And Airway Mucus Secretion And Airway Hyperresponsiveness In Asthma Mouse

Background Asthma is a chronic airway inflammatory disorder in which many cells(eosinophil,mast,T lymphocyte,neutrophil and airway epithelium) and cytokines participate associated with variable airflow limitation, airway mucus hypersecretion and airway hyperresponsiveness(AHR).Increasing evidence suggests that eosinophils (Eos) play a central role in the pathogenesis of asthma. Eosinophils develop from CD34~+ hematopoietic progenitor cells. After exposure to allergen, actived TH2 lymphocytes in the airways secret sereval chemokines and chemoattractants. With the effect of IL-5 and eotaxin, CD34~+ progenitor cells multiply and differentiate to mature eosinophils which traffic from bone marrow (BM) into airway mucosa via the circulation.The chemokine-like factor 1 (CKLF1) is a novel human cytokine isolated from PHA-stimulated U937 cells, which is firstly discoveried and cloned from the labortory of peking university center for human disease genomics. The CKLF1, which belongs to a novel gene family, has chemotaxis effect on different leukocytes both in vitro and in vivo. It can also stimulate proliferation of skeletal muscle cells and bone marrow cells. CKLF1 has a CC motif and the key amino acids around the motif are identical with those of TARC/CCL17 (Thymus- and activation-regulated chemokine) andMDC/CCL22 (Macrophage Derived Chemokine), the cognate ligands for CCR4 which are up-regulated in the airways of atopic asthmatics. Thus, CKLF1 is a novel functional ligand for CCR4. CKLF1 is also found that it is up-regulated in activated CD4~+ and CD8~+ cells. A single intramuscular injection of CKLF1 plasmid DNA into BALB/c mice cause dramatic pathological changes in the lungs of treated mice. Those changes are similar to phenomena observed in asthma. C19 and C27 are C terminatio peptide of CKLF1, which are obtained by chemical synthesis. C19 and C27 are functional ligands for CCR4 and CCR5, they also exhibit chemotactic effect on leukocytes. Those data suggest that CKLF1 may play an important role in the pathogenesis of asthma. In this study we investigated the effects of intraperitoneal injection of C19 and C27 of C terminatio peptide of CKLF1 by different dosages on the airway inflammation and airway mucus secretion and airway hyperresponsiveness in a mouse model of asthma.Objective Based on a mouse model of asthma we created previously, intraperitoneal injection of C19 and C27 of C terminatio peptide of CKLF1 by different dosages , then we examined the effects on the airway inflammation and airway mucus secretion and hyperresponsiveness.Methods Male C57BL/6 mice, 6-8 week old, were sensitized two times and challenged three times by ovalbumin(OVA) as OVA/OVA group, and mice were treated by normal saline as control group. Before 30 minutes of every challenge, to intraperitoneal injection of C19 and C27 respectively by different dosages. So we assigned mice to four groups: Normal saline solution group(NS group), asthma model group(OVA group), C19 -treated groups, C27-treated groups. Then 24 hours after the last challenge, the bronchoalveolar lavage(BALF) inflammatory cell counts and the pathomorphological changes in the lung were analyzed; the goblet cell hyperplasia ratio(HR) and the epithelial cell mucus occupying ratio(MOR) were also measured; the level of airway responsiveness was detected.Results:1. The changes of Eos population in BALF after C19 and C27-treated.We found Eos increased obviously in BALF after OVA challenge compared with NS group, p<0.05. Compared with OVA group, Eos in BALF was reduced significantly in C19-treated groups, p<0.05; but Eos in BALF was not reduced significantly by C27.2. The change of pulmonary pathology after C19 and C27-treated.In NS group mice, there were no Eos accumulation around airways and vessels, and no mucus secretion in the epithelial cells. However, in OVA group, we observed a significant increase in Eos infiltration around airways and vessels, and mucus hypersecretion in the epithelial cells. In C19-treated mice, there were little inflammatory cells around airways and vessels, however mucus hypersecretion has no change compared with OVA group. In C27-treated mice, both inflammatory cells and mucus hypersecretion have no change compared with OVA group.3. Quantitative analysis of airways mucus after C19/C27-treated.HR and MOR of C19-treated groups, C27-treated groups and OVA group increased significantly compared with NS group, p<0.05; but HR and MOR of C19-treated groups and C27-treated groups were still not significant difference compared with OVA group.4. The change of airway responsiveness after C19 and C27-treated.Pleural pressure (Ppl) of C19-treated groups were reduced significantly compared with OVA group, p<0.05; but Ppl of C27-treated groups were not significant difference compared with OVA group.Conclusion1. Eos in BALF can be reduced in C19-treated groups, C19 peptide can inhibit the airway inflammation and hyperresponsiveness; but C27 peptide has no effect on the airway inflammation and hyperresponsiveness.2. Both C19 peptide and C27 peptide have no effect on the airway mucus hypersecretion.