RESUMO
Aldo-keto reductase 1C3 (AKR1C3) is an enzyme involved in metabolizing prostaglandins (PGs) and sex hormones. It metabolizes PGD2 to 9α11ß-PGF2 , diverting the spontaneous conversion of PGD2 to the PPARγ agonist, 15-Deoxy-Delta-12, 14-prostaglandin J2 (15d-PGJ2 ). AKR1C3 is overexpressed in various malignancies, suggesting a tumor promoting function. This work investigates AKR1C3 expression in human non-melanoma skin cancers, revealing overexpression in squamous cell carcinoma (SCC). Effects of AKR1C3 overexpression were then evaluated using three SCC cell lines. AKR1C3 was detected in all SCC cell lines and its expression was upregulated in response to its substrate, PGD2 . Although attenuating AKR1C3 expression in SCC cells by siRNA did not affect growth, treatment with PGD2 and its dehydration metabolite, 15d-PGJ2 , decreased SCC proliferation in a PPARγ-dependent manner. In addition, treatment with the PPARγ agonist pioglitazone profoundly inhibited SCC proliferation. Finally, we generated an SCC cell line that stably overexpressed AKR1C3 (SCC-AKR1C3). SCC-AKR1C3 metabolized PGD2 to 9α11ß-PGF2 12-fold faster than the parent cell line and was protected from the antiproliferative effect mediated by PGD2 . This work suggests that PGD2 and its metabolite 15d-PGJ2 attenuate SCC proliferation in a PPARγ-dependent manner, therefore activation of PPARγ by agonists such as pioglitazone may benefit those at high risk of SCC.
Assuntos
3-Hidroxiesteroide Desidrogenases/metabolismo , Carcinoma de Células Escamosas/metabolismo , Regulação Neoplásica da Expressão Gênica/fisiologia , Hidroxiprostaglandina Desidrogenases/metabolismo , Prostaglandinas/metabolismo , Neoplasias Cutâneas/metabolismo , Regulação para Cima/fisiologia , Membro C3 da Família 1 de alfa-Ceto Redutase , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Proliferação de Células , Células Cultivadas , Humanos , PPAR gama/metabolismo , Prostaglandina D2/análogos & derivados , Prostaglandina D2/metabolismo , Prostaglandina D2/farmacologia , RNA Interferente Pequeno/farmacologia , Pele/efeitos dos fármacos , Pele/metabolismo , Pele/patologia , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologiaRESUMO
Atopic dermatitis (AD) is characterized by epidermal tight junction (TJ) defects and a propensity for Staphylococcus aureus skin infections. S. aureus is sensed by many pattern recognition receptors, including Toll-like receptor 2 (TLR2). We hypothesized that an effective innate immune response will include skin barrier repair, and that this response is impaired in AD subjects. S. aureus-derived peptidoglycan (PGN) and synthetic TLR2 agonists enhanced TJ barrier and increased expression of TJ proteins, claudin-1 (CLDN1), claudin-23 (CLDN23), occludin, and Zonulae occludens 1 (ZO-1) in primary human keratinocytes. A TLR2 agonist enhanced skin barrier recovery in human epidermis wounded by tape stripping. Tlr2(-/-) mice had a delayed and incomplete barrier recovery following tape stripping. AD subjects had reduced epidermal TLR2 expression as compared with nonatopic subjects, which inversely correlated (r=-0.654, P=0.0004) with transepidermal water loss (TEWL). These observations indicate that TLR2 activation enhances skin barrier in murine and human skin and is an important part of a wound repair response. Reduced epidermal TLR2 expression observed in AD patients may have a role in their incompetent skin barrier.
Assuntos
Dermatite Atópica/metabolismo , Epiderme/metabolismo , Junções Íntimas/metabolismo , Receptor 2 Toll-Like/metabolismo , Animais , Anticorpos Neutralizantes/farmacologia , Proteínas de Bactérias/farmacologia , Dermatite Atópica/imunologia , Dermatite Atópica/patologia , Epiderme/imunologia , Epiderme/patologia , Feminino , Prepúcio do Pênis/citologia , Humanos , Queratinócitos/citologia , Queratinócitos/imunologia , Queratinócitos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Peptidoglicano/farmacologia , Permeabilidade , RNA Mensageiro/metabolismo , Junções Íntimas/imunologia , Junções Íntimas/patologia , Receptor 1 Toll-Like/genética , Receptor 1 Toll-Like/imunologia , Receptor 1 Toll-Like/metabolismo , Receptor 2 Toll-Like/agonistas , Receptor 2 Toll-Like/genética , Estimulação Elétrica Nervosa Transcutânea , Cicatrização/fisiologiaRESUMO
Aldo-keto reductase 1C3 (AKR1C3) has been shown to mediate the metabolism of sex hormones and prostaglandin D(2) (PGD(2)), a lipid mediator that promotes skin inflammation in atopic dermatitis (AD). As both have a role in skin function and pathology, we first sought to investigate the expression pattern of AKR1C3 in normal human epidermis. Immunofluorescence revealed a strong expression of AKR1C3 in the differentiated suprabasal layers compared with the basal layer. Western blot analysis and quantitative PCR confirmed that AKR1C3 expression was also upregulated in differentiation-induced primary human keratinocytes (PHKs). To investigate the functional role of AKR1C3 during PHK differentiation, its expression and activity (measured as PGD(2) reduction to 9α,11ß-PGF(2) by ELISA) were impaired by small interfering RNA or 2'-hydroxyflavanone, respectively. Cytokeratin 10 (K10) and loricrin expression were then examined by western blot analysis, thus revealing altered expression of these differentiation markers. Finally, following an observation that the AD-associated mediator, PGD(2), upregulated AKR1C3 expression in PHKs, we used immunofluorescence to examine AKR1C3 expression in AD and psoriasis lesions. AKR1C3 was found to be upregulated in AD but not in psoriasis lesions compared with non-lesional skin. Our work demonstrates a function for AKR1C3 in differentiation-associated gene regulation and also suggests a role in supporting inflammation in AD.