Study on Immune and Molecular Regulation of Allergic Asthmatic Disease
Date Issued
2009
Date
2009
Author(s)
Huang, Hsin-Ying
Abstract
Asthma is caused by aberrant Th2 responses to harmless inhaled allergens underlaid a disturbance in the balance between Th1- and Th2-mediated immune responses. Eosinophilia plays the major role in the pathogenesis of asthma and correlates with the up-regulation of eotaxin, which, together with interleukin (IL)-5, is important for differentiation, chemo-attraction, degranulation, and survival of eosinophils in local tissue. Mediators released by eosinophils directly damage the epithelium cells and induce smooth muscles constriction and mucus secretion, subsequently result in airway hyperresponsiveness. Many therapeutic strategies for asthma are based on modulating the allergic responses through antibody or inhibitor. However, gene regulation in mRNA levels is more efficient than in protein levels. Recently, RNAi has been shown to be an efficacious in transcriptional or posttranscriptional silencing target genes. The present study aimed to investigate the role of eotaxin and IL-5 short hairpin RNAs (shRNAs) and their synergistic effect on airway inflammation in an ovalbumin (OVA)-induced murine model of asthma. Lentivirus-delivered shRNAs were used to suppress the expression of eotaxin and/or IL-5 in local tissue and we found that intra-tracheal administration of lentivirus containing eotaxin or IL-5 shRNAs expressing cassette (eoSEC3.3 or IL5SEC4) efficiently moderated the characteristics of asthma, including airway hyper-responsiveness, cellular infiltration of lung tissues, and eotaxin and IL-5 levels in bronchio-alveolar lavage fluid. concomitant administration of lentiviruses expressing IL-5 and eotaxin shRNAs (IL5SEC4 + eoSEC3.3) also moderated the symptoms of asthma in a mouse model. However, there was no effect on OVA-specific IgE level neither in single shRNA treated mice nor combination of eotxin and IL-5 shRNAs treated ones.n addition, Th1 cells and regulatory T cells are thought to modulate the allergen-induced Th2 responses. Peptide alterations of T cell epitopes with single or few amino acid variations can have drastic effects on the outcome of this recognition. Altered peptide ligands (APLs) can act as modulators of immune responses through induction of different cytokines production profile or differentiation of different lineage of T cells. In this study, we would like to design APLs, which modified from OVA323-339 peptide, major epitope of DO11.10 TCR transgenic mice, and investigate whether APLs affect the function of allergen-specific T cells, such as differentiating toward Treg or Th1 and then we will investigate whether APLs could modulate the airway inflammation in OVA-induced murine of asthma mice, as an allergen-specific immunotherapy approach. We synthesized six APLs with a single amino acid substitution of the OVA323-339 (WT) and examined the phenotypes of OVA-specific T cells activated by these peptide analogues. In our results, five of six peptide analogues (E333A, H331Q, H331F, H331R, and H331E,) did not induce proliferation, TCR internalization, and cytokines production of DO11.10 T cells, being null peptides. Whereas, N335A induced activation of T cells in high concentration, likely being a weak agonist. Furthermore, N335A-primed T cells produced higher level of INF-γ and lower level of IL-4 compared with WT-primed T cells upon WT restimulation, indicating that N335A likely skewed T cells toward Th1 cells. However, T cells stimulated with six peptide analogues did not show any properties of Treg cells. n our study, local delivery of lentiviruses expressing IL-5 and eotaxin shRNAs provides a potential tool in moderating airway inflammation and also has the potential for developing clinical therapy based on the application of shRNAs of chemokines and cytokines involved in T helper 2 cell inflammation and eosinophilia. In addition, we found that the OVA peptide analogous, N335A, could induce OVA-specific T cells to differentiate into Th1 cells and then we will deliver N335A into OVA-sensitized mice to investigate whether N335A could regulate the allergic responses and inhibit the airway inflammation in murine model of asthma.
Subjects
asthma
shRNA
IL-5, eotaxin
altered peptide ligands
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