DNA vaccine encoding Der p2 allergen down-regulates STAT6 expression in mouse model of allergen-induced allergic airway inflammation

Background Activation of signal transducer and activator of transcription 6 （STAT6） plays a critical role in the late phase of Th2-dependent allergy induction. STAT6 is essential to Th2 cell differentiation, recruitment, and effector function. Our previous study confirmed that DNA vaccination inhibited STAT6 expression of spleen cells induced by allergen. In the present study, we determined whether DNA vaccine encoding Dermatophagoides pteronyssinus group 2 （Der p2 ） could down-regulate the expression and activation of STAT6 in lung tissue from asthmatic mice. Methods After DNA vaccine immunization, BALB/c mice were sensitized by intmperitoneal injection and challenged by intranasal instillation of rDer p2. The levels of the cytokines IL-4 and IL-13 in BAL fluid were measured by enzyme-linked immunosorbent assay. The lung tissue was assessed by immunohistochemical staining with anti-STAT6. The protein expression of STAT6 was determined by Western blot. The activation of STAT6 binding ability was analyzed with electrophoretic mobility shift assay. Results DNA vaccine encoding Der p2 allergen effectively decreased the levels of IL-4 and IL-13 in the asthmatic mice. Histological evidence and Western blot showed that the expression of STAT6 in the DNA treated mice was markedly attenuated. STAT6 binding to specific DNA motif in lung tissue from the gene vaccinated mice was inhibited. Condusion DNA vaccine encoding Der p2 prevents allergic pulmonary inflammation probably by inhibiting the STAT6 signaling pathway in mice with Der p2 allergen-induced allergic airway infammafion.

Inhibition of allergic airway inflammation by antisense-induced blockade of STAT6 expression

Background The signal transducer and activator of transcription 6 （STAT6） expression in lung epithelial cells plays a pivotal role in asthma pathogenesis. Activation of STAT6 expression results in T helper cell type 2 （Th2） cell differentiation leading to Th2-mediated IgE production, development of allergic airway inflammation and hyperreactivity. Therefore, antagonizing the expression and/or the function of STAT6 could be used as a mode of therapy for allergic airway inflammation. Methods In this study, we synthesized a 20-mer phosphorothioate antisense oligonucleotide （ASODN） overlapping the translation starting site of STAT6 and constructed STAT6 antisense RNA （pANTI-STAT6）, then transfected them into murine spleen lymphocytes and analyzed the effects of antagonizing STAT6 function in vitro and in a murine model of asthma. Results In vitro, we showed suppression of STAT6 expression and interleukin （IL）-4 production of lymphocytes by STAT6 ASODN. This effect was more prominent when cells were cultured with pANTI-STAT6. In a murine model of asthma associated with allergic pulmonary inflammation in ovalbumin （OVA）-sensitized mice, local intranasal administration of fluorescein isothiocyanate （FITC）-Iabeled STAT6 ASODN to DNA uptake in lung cells was accompanied by a reduction of intracellular STAT6 expression. Such intrapulmonary blockade of STAT6 expression abrogated signs of lung inflammation, infiltration of eosinophils and Th2 cytokine production. Conclusion These data suggest a critical role of STAT6 in the pathogenesis of asthma and the use of local delivery of STAT6 ASODN as a novel approach for the treatment of allergic airway inflammation such as in asthma.

Effect of compound Sophorae Flavescentis Jiechangrongcapsule on expression of NF-κB p65 and STAT6 in theintestinal mucosa of patients with ulcerative colitis

The effects of compound Sophorae Flavescen-tis Jiechangrong capsule(CSFJC)on the expression of nuclear factor-κB p65(NF-κB p65)and signal transducer and activator of transcription 6(STAT6)in the intestinal mucosa of patients with ulcerative colitis and the possible mechanism were investigated.Eighteen patients with ulcerative colitis were randomly divided into a traditional Chinese medicine(TCM)group(n=11)treated by CSFJC and a western medicine(WM)group(n=7)treated by Sulfasalazine tablets.The treatment duration lasted eight weeks.Before and after the treatment,the symptoms and the physical signs were observed,and the routine stool test,the colonoscopy,and pathological examination were performed in the two groups.The expression levels of NF-κB p65 and STAT6 were detected by using immuno-histochemistry.The results showed that the total effective rate of the curative effectiveness in TCM and WM groups was 100%and 71.4%,respectively,and the total effective rate of colonic mucosa lesion in TCM and WM groups was 90.9%and 71.4%,respectively,with the differences being significant(all P<0.05).The total effective rate of syndromes of damp-heat blocking according to the TCM in TCM and WM groups was 90.9%and 71.4%,respectively.After the treatment,the expression of NF-κB p65 and STAT6 in the two groups was decreased,and the decrease of NF-κB p65 and STAT6 expression in TCM group was more significant than in WM group(P<0.05).It was concluded that CSFJC can inhibit the activation and expression of NF-κB p65 and STAT6 in the intestinal mucosa of patients with ulcerative colitis,which is a possible mechanism for CSFJC treating ulcerative colitis.

Apoptosis induced by short hairpin RNA-mediated STAT6 gene silencing in human colon cancer cells

Background The relationship between signal transduction and tumors has become one of the loci in cancer research. Signal transducer and activator of the transcription 6 （STAT6） signaling pathway is found to be activated in some cancer cells. But the function of the pathway in cancer cells is unknown. This study was undertaken to investigate the effect of the Stat6 signaling pathway on apoptosis in human colon cancer cells （HT-29 cells） and the possible mechanism of Stat6 by RNA interference techniques.