No abstract

The kinetics of cytokine expression was evaluated in whole blood from high-IgE beagles previously sensitized to house dust mites (HDM) and known to develop clinical signs compatible with atopic dermatitis (AD) upon allergen exposure. Six high-IgE beagles were environmentally challenged daily for 3 h on three consecutive days with a HDM solution. Clinical signs were evaluated before, during, and after the conclusion of the challenge (days 0, 2, 4 and 17) and expression analyses of Th2 (IL-4 and IL-13) and regulatory (IL-10 and TGF-beta) cytokine mRNA were undertaken on blood samples at each time point using real-time polymerase chain reaction. Multiple comparison used to detect significant differences in clinical scores and expression levels of cytokine mRNA revealed that the clinical scores on days 2 and 4 were higher than those on days 0 and 17 (P < 0.05) but no temporal differences in the expression levels of IL-4 and IL-13 mRNA. Expression of TGF-beta mRNA was, however, significantly lower on day 4 (P < 0.05) and the expression of IL-10 mRNA on days 4 and 17 was significantly lower than those on days 0 and 2 (P < 0.05). The results indicate that allergen challenge decreases mRNA expression of regulatory cytokines in whole blood without enhanced mRNA expression of Th2 cytokines and suggest aberrant regulatory T-cell function in the immunopathogenesis of AD in high-IgE beagles.

The regulation of hepatic very-low-density lipoprotein (VLDL) secretion plays an important role in the pathogenesis of dyslipidemia and fatty liver diseases. VLDL is controlled by hepatic microsomal triglyceride transfer protein (MTTP). Mttp is regulated by carbohydrate response element binding protein (ChREBP) and small heterodimer partner (SHP). However, it is unclear whether both coordinately regulate Mttp expression and VLDL secretion. Here, adenoviral overexpression of ChREBP and SHP in rat primary hepatocytes induced and suppressed Mttp mRNA, respectively. However, Mttp induction by ChREBP was much more potent than suppression by SHP. Promoter assays of Mttp and the liver type pyruvate kinase gene revealed that SHP and ChREBP did not affect the transcriptional activity of each other. Mttp mRNA and protein levels of Shp−/− mice were similar to those of wild-types; however, those of Chrebp−/−Shp−/− and Chrebp−/− mice were significantly much lower. Consistent with this, the VLDL particle number and VLDL secretion rates in Shp−/− mice were similar to wild-types but were much lower in Chrebp−/− and Chrebp−/−Shp−/− mice. These findings suggest that ChREBP, rather than SHP, regulates VLDL secretion under normal conditions and that ChREBP and SHP do not affect the transcriptional activities of each other.

ABSTRACT. Epidermal keratinocytes have the potential to produce inflammatory mediators that are considered to play an important role in skin diseases such as atopic dermatitis (AD). Thus, cell lines of canine epidermal keratinocytes are useful for studying the biological reactivity of keratinocytes in vitro. However, there has been no report on properly analyzing the phenotype of canine keratinocyte cell lines. In this work, we performed phenotypic analysis of CPEK, which was derived from the epidermis of an adult dog in order to examine the phenotypic similarity with epidermal keratinocytes. The present findings indicated that CPEK cells expressed markers for epidermal keratinocytes including cytokeratin 14, α 6 integrin and PCNA. Our findings demonstrated that CPEK could be a useful cell line for investigating the central role of epidermal keratinocytes in the pathogenesis of AD in vitro.

ABSTRACT. Chemokines are important regulators of the selective recruitment of inflammatory cells into sites of allergic inflammation. Since canine atopic dermatitis (AD) shares many clinical features of human AD, patterns of chemokine production in dogs may also be similar with those in humans. The aim of this study was to examine mRNA expression of CCL27 and CCL28 in lesional skin of dogs with AD to demonstrate similarity of chemokine production with human counterparts. RNA was extracted from skin biopsy specimens of 12 dogs with AD. The mRNA expression of CC chemokines (CCL4, CCL19, CCL20, CCL21, CCL24, CCL27 and CCL28) was analyzed by quantitative real-time PCR and was compared between lesional and non-lesional skin. Seven types of chemokines examined were constitutively expressed in both lesional and non-lesional skin. It was found that mRNA expression levels of CCL27 and CCL28 among the chemokines were significantly different between lesional and non-lesional skin (P<0.05). Expression level of CCL27 mRNA in lesional skin was significantly lower than that in non-lesional skin. On the other hand, CCL28 mRNA expression in lesional skin was found to be higher than that in non-lesional skin. These results suggest that CCL28 but not CCL27 may play important roles in immunopathogenesis of canine AD, indicating that experimental canine study may provide additional information that can be extrapolated to human AD.