RESUMO
Our previous studies revealed that REIC/Dkk-3 was expressed various tissues, including skin keratinocytes. The aim of the present study was to identify the factors that regulate the expression of the dickkopf Wnt signaling pathway inhibitor 3 (REIC/Dkk3) tumor suppressor gene in normal human skin keratinocytes (NHKs). Several growth factors and cytokines that have previously been reported to be involved in the growth and differentiation of keratinocytes were screened as potential regulators. Western blot analysis was performed using protein from NHKs cultured with/without various factors including the epidermal growth factor, tumor necrosis factorα, transforming growth factorß, interleukin (IL)1F9, IL6, IL8 and Ca2+. The results indicated that only TNFα downregulated REIC/Dkk3 expression in NHKs. Subsequently, TNFα was confirmed to reduce the expression levels of REIC/Dkk3 in mouse skin tissue and hair culture models. TNFαmediated downregulation of REIC/Dkk3 expression in NHKs was abrogated by the addition of a TNFαspecific antibody. In conclusion, the results indicate that TNFα downregulates REIC/Dkk3 expression in normal skin keratinocytes.
Assuntos
Regulação para Baixo , Peptídeos e Proteínas de Sinalização Intercelular/biossíntese , Queratinócitos/metabolismo , Pele/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Proteínas Supressoras de Tumor/biossíntese , Proteínas Adaptadoras de Transdução de Sinal , Animais , Quimiocinas , Feminino , Humanos , Queratinócitos/citologia , Masculino , Camundongos , Pele/citologiaRESUMO
We investigated the expression pattern of Dkk-3, a secreted Wnt pathway inhibitor, in mouse intestinal tissue and three-dimensional cultured Caco-2 spheroids. Dkk-3 was expressed at the bottom of crypts from the mouse small intestine. Human colon adenocarcinoma Caco-2 cells expressed Dkk-3 under a semi-confluent condition, but Dkk-3 expression was seen in only some of the Caco-2 cells when the cells were sparse. Caco-2 cells formed hollow spheroids in Matrigel, and the layer-forming cells in the hollow spheroids expressed Dkk-3. Our results demonstrated that Dkk-3 might affect intestinal cells when the fate of stem cells changes.
