Estudo imuno-histoquímico da presença de miofibroblastos e da expressão do fator transformador de crescimento-beta1, interferon gama, mataloproteinase de matriz 13 e indutor de metaloproteinases de matriz em lesões odontogênicas epiteliais / Immunohistochemical study of the presence of myofibroblasts and the expression of transforming growth factor-beta1, interferon gamma, mataloproteinase matrix 13 and matrix metalloproteinase inducer in odontogenic epithelial lesions

Os miofibroblastos são células que apresentam um fenótipo híbrido exibindo características morfológicas de fibroblastos e de células musculares lisas, sendo a aquisição de tal fenótipo denominada diferenciação, passando então a expressar a a-SMA, a qual é importante na identificação dessas células. Estudos têm sugerido que os miofibrobíastos apresentam relação com a agressividade de diversas lesões e que o seu processo de diferenciação estaria relacionado à expressão do TGF-pl e do IFN-y atuando, respectivamente, no estímulo e na inibição dessa diferenciação. O objetivo deste trabalho foi investigar o papel dos miofibroblastos em lesões odontogênicas epiteliais, relacionando-os à agressividade das lesões e analisar por meio da imuno-histoquímica. a expressão do TGF-pl e IFN-y no processo de diferenciação, além da análise da MMP-13 que é ativada por miofibroblastos e do indutor de metaloproteinases de matriz (EMMPRIN) como precursor desta MMP. A amostra foi constituída por 20 ameloblastomas sólidos, 10 ameloblastomas unicfsticos, 20 ceratocistos odontogênicos e 20 tumores odontogênícos adenomatóides. Para a avaliação dos miofibroblastos, foram quantificadas as células imunorreativas ao anticorpo a-SMA presentes no tecido conjuntivo, próximo ao tecido epitelial. As expressões de TGF-pl, IFN-y, MMP-13 e EMMPRIN, foram avaliadas no componente epitelial e no conjuntivo, estabelecendo-se o percentual de imunorreatividade e atribuindo-se escores de 0 a 4. A análise dos miofibroblastos evidenciou maior concentração nos ameloblastomas sólidos (média de 30,55), seguido pelos ceratocistos odontogênicos (22,50), ameloblastomas unicísticos (20,80) e tumores odontogênicos adenomatóides (19,15) com valor de p= 0,001. Não foi encontrada correlação significativa entre TGF-pl e IFN-y no processo de diferenciação dos miofibroblastos, bem como na relação entre a quantidade de miofibroblastos e a expressão da MMP-13. Constatou-se, correlação estatística entre MMP-13 e TGF-pi (r= 0,087; p= 0,011) além de significante correlação entre MMP-13 e IFN-y (r=0,348; p=0,003). Entre EMMPRÍN e MMP-13 verificou-se significância (r= 0,474; p<0,001) assim como entre EMMPRIN e IFN-y (r=0,393; p=0,001). A maior quantidade de miofibroblastos evidenciada nos ameloblastomas sólidos, ceratocistos odontogênicos e ameloblastomas unicísticos sugere que estas células podem ser um dos fatores responsáveis para um comportamento biológico mais agressivo destas lesões, embora a população de miofibroblastos não tenha apresentado correlação com TGF- -pi, IFN-y ,MMP-13 e EMMPRIN. Quanto a correlação evidenciada entre MMP-13 e TGF-pl, isto pode sugerir um papel indutor do TGF-pl para a expressão da MMP-13, assim como os resultados deste estudo reforçam a relação bem estabelecida do EMMPRIN como indutor da MMP-13. Constatou-se também relação entre EMMPRIN e IFN-y assim como entre MMP-13 e IFN-y sugerindo, dessa forma, um sinergismo na ação anti-fibrótica desses marcadores.

Myofibroblasts are cells that exhibit a hybrid phenotype, sharing the morphoíogical characteristics of fibroblasts and smooth muscle cells, which is acquired during a process called differentiation. These cells then start to express a-SMA, a marker that can be used for their identification. Studies suggest that myofibroblasts are related to the aggressiveness of different tumors and that TGF-pl and IFN-y play a role in myofibroblast differentiation, stimulating or inhibiting this differentiation, respectively. The objective of this study was to investigate the role of myofibroblasts in epithelial odontogenic tumors, correlating the presence of these cells with the aggressiveness of the tumor. Immunohistochemistry was used to evaluate the expression of TGF-pl and IFN-y in myofibroblast differentiation, as well as the expression of MMP-13, which is activated by myofibroblasts, and of EMMPRIN (extracellular matrix metalloproteinase inducer) as a precursor of this MMP. The sample consisted of 20 solid ameloblastomas, 10 unicystic ameloblastomas, 20 odontogenic keratocysts, and 20 adenomatoid odontogenic tumors. For evaluation of myofibroblasts, anti-a-SMA-immunoreactive cells were quantified in connective tissue close to the epithelium. Immunoexpression of TGF-pl, IFN-y, MMP-13 and EMMPRIN was evaluaíed in the epithelial and connective tissue components, attributing scores of 0 to 4. The results showed a higher concentration of myofibroblasts in solid ameloblastomas (mean of 30.55), followed by odontogenic keratocysts (22.50), unicystic ameloblastomas (20.80), and adenomatoid odontogenic tumors (19.15) (p=0.00). No significant correlation between TGF-pl and IFN-y was observed during the process of myofibroblast differentiation. There was also no correlation between the quantity of myofibroblasts and MMP-13 expression. Significant correlations were found between MMP-13 and TGF-pi (r=0.087; p=0.01 1), between MMP-13 and ÍFN-y (r=0.348; p=0.003), as well as between EMMPRIN and MMP-13 (r=0.474; /xO.001) and between EMMPRIN and IFN-y (r=0.393; p=0.00). The higher quantity of myofibroblasts observed in solid ameloblastomas, odontogenic keratocysts and unicystic ameloblastomas suggests that these cells are one of the factors responsible for the more aggressive biological behavior of these tumors, although the myofibroblast population was not correlated with TGF-01, IFN-y, MMP-13 or EMMPRIN. The correlation between MMP-13 and TGF-pl suggests that the latter induces the expression of this metalloproteinase. The present results also support the well-established role of EMMPRIN as an inducer of MMP-13. Furthermore, the relationship between EMMPRIN and IFN-y and between MMP-13 and IFN-y suggests synergism in the antifibrotic effect of these markers.

Inhibition of caspase-8 activity reduces IFN-gamma expression by T cells from Leishmania major infection

Following infection with Leishmania major, T cell activation and apoptosis can be detected in draining lymph nodes of C57BL/6-infected mice. We investigated the mechanisms involved in apoptosis and cytokine expression following Tcellactivation. After two weeks of infection, apoptotic T cells were not detected in draining lymph nodes but activation with anti-CD3 induced apoptosis in both CD4 and CD8 T cells. Treatment with anti-FasLigand, caspase-8 or caspase- 9 inhibitors did not block activation-induced T-cell death. We also investigated whether the blockade of caspase-8 activity would affect the expression of type-1 or type-2 cytokines. At early stages of infection, both CD4 and CD8 T cells expressed IFN-gamma upon activation. Treatment with the caspase-8 inhibitor zIETD-fmk (benzyl-oxycarbonyl-Ile- Glu(OMe)-Thr-Asp(OMe)-fluoromethyl ketone) reduced the proportion of CD8 T cells and IFN-gamma expression in both CD4 and CD8T cells. We conclude that a non apoptotic role of caspase-8 activity may be required for T cell-mediated type-1 responses during L. major infection.

A ativação e a morte por apoptose de linfócitos T foram observadas em linfonodos drenantes de camundongos C57BL/6 infectados com Leishmania major. Investigamos os mecanismos envolvidos na apoptose e na expressão de citocinas após a ativação de linfócitos T. Após duas semanas de infecção, embora as células apoptóticas ainda não sejam detectadas em linfonodos drenantes, células T CD4 e CD8 sofrem apoptose após ativação com anti-CD3. O tratamento com anticorpo antagonista anti-Ligante de Fas, ou com inibidores das caspases-8 e 9, não bloqueou a morte induzida por ativação das células T. Investigamos também se a inibição da atividade da caspase-8 poderia afetar a expressão de citocinas tipo-1 ou tipo-2. Nos estágios iniciais da infecção, células T CD4 e CD8 de animais infectados com L. major expressaram IFN-gama após ativação. O tratamento com o inibidor de caspase-8 zIETD (benzoil-oxicarbonil-Ile-Glu(OMe)-Thr-Asp(OMe)-fluorometilcetona) durante a estimulação de células T reduziu a proporção de células T CD8 e a expressão de IFN-gama por células T CD4 e CD8. Concluimos que a atividade não apoptótica de caspase-8 pode ser necessária para o estabelecimento da imunidade mediada por células T durante a infecção por L. major.

Serum levels of interleukin-6, tumor necrosis factor-alpha and interferon-gama in infants with and without dengue

This study compared the serum levels of IL-6, TNF-alpha and IFN-gamma, in children under 1 year of age with and without dengue. Sera were collected from a total of 41 children living in the Department of Antioquia, Colombia (27 patients with dengue and 14 controls). The results showed higher cytokine levels in children with dengue than without dengue, with statistically significant differences for IL-6 and IFN-gamma. No statistically significant differences were found between clinical forms, although IL-6 and IFN-gamma levels were higher in dengue fever cases than in dengue hemorrhagic fever cases. On the other hand, TNF-alpha levels were higher in dengue hemorrhagic fever than in dengue fever. The levels of IL-6 and TNF-alpha were higher in secondary infection than in primary infection, although IFN-gamma levels were higher in primary infection. These results suggest that IL-6, TNF-alpha and IFN-gamma are involved in dengue infection independently of the clinical form.

Este estudo comparou os níveis séricos de IL-6, TNF-alfa e IFN-gama, em crianças menores de um ano com e sem dengue. Os soros foram coletados de um total de 41 crianças residentes no Departamento de Antioquia, Colômbia (27 pacientes com dengue e 14 controles). Os resultados mostraram níveis de citoquinas mais elevadas em crianças com dengue do que naquelas sem dengue, com diferenças estatisticamente significativas para IL-6 and IFN-gama. Não houve diferenças estatisticamente significativas entre formas clínicas, embora os níveis de IL-6 e IFN-gama estivessem mais elevados nos casos de febre do dengue que nos casos de febre hemorrágica do dengue. Por outro lado, os níveis de TNF-alfa estavam mais elevados na febre hemorrágica do dengue que na febre do dengue. Os níveis de IL-6 and TNF-alfa estavam mais elevados em infecções secundárias que em infecções primarias, embora os níveis de IFN-gama estivessem mais elevados em infecções primárias. Estes resultados sugerem que IL-6, TNF-alfa e IFN-gama estejam envolvidos na infecção do dengue, independentemente da forma clínica.

Las células dendríticas en la infección por el VIH-1 / Dendritic cells during the HIV-1 infection

Las células dendríticas son un componente de la inmunidad innata que cumple con la función crucial de activar los linfocitos T vírgenes. Son una de las células blanco de la infección por el VIH-1, aunque la replicación de este virus en las células dendríticas es muy inferior a la observada en los linfocitos T CD4+. Sin embargo, las células dendríticas almacenan viriones por largo tiempo, para transmitirlos después a otras células susceptibles, y se convierten en uno de los reservorios más importantes del VIH-1. Durante esta infección, las células dendríticas hacen parte inicialmente de la respuesta inmune contra el VIH-1, pero luego exhiben alteraciones cuantitativas y funcionales que potencian la inmunodeficiencia característica de esa infección. El papel que cumplen las células dendríticas en la inducción de la respuesta inmune innata y adaptativa indica que tienen un potencial terapéutico interesante en el desarrollo de vacunas e inmunoterapia para la infección por el VIH-1.

Dendritic cells are components of the innate immunity crucial for activating naïve T cells. They are one of the target cells for HIV-1 infection, but their ability to replicate HIV-1 is much more limited than that exhibited by CD4+ T cells. However, they have the capacity to store the virus for long periods of time which are able to infect susceptible cells later on. Therefore, dendritic cells are considered as one of the most important reservoirs for the HIV-1. At early stages of this infection, dendritic cells also contribute with the anti-HIV-1 immune response, but then they exhibit quantitative and functional alterations enhancing the severe immunodeficiency characteristic of this infection. The important role of dendritic cells in inducing innate and adaptive immune responses indicates that these cells have a promising therapeutic potential for the development of vaccines and immunotherapy for HIV-1 infection.

Growth Suppression of Ovarian Cancer Cells by Interferon-gama / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Growth regulation of cancer cells very frequently involves tumor suppressor gene p53, Rb and cell cycle regulator, however the molecular biologic mechanisms of growth regulation in ovarian carcinoma cells are not fully defined. To assess the mechanism of growth suppression, we treated IFN-gama in ovarian carcinoma cells. MATERIALS AND METHODS: Growth suppression by treatment of IFN-gama was determined by cell proliferation assay in ovarian carcinoma cell lines. Apoptosis was determined by DNA fragmentation assay and electron microscopy. Molecular mechanism of the apoptosis in ovarian carcinoma cell by IFN-gama was further analyzed by the western blot. RESULTS: We found that IFN-gama had remarkable growth- suppressive effects in PA-1 and A2774 ovarian carcinoma cells in a time-dependent manner. Apoptosis was observed in PA-1 and A2774 cell following treatment of IFN- gama by DNA fragmentation assay and EM. The expression of IRF-1 protein from A2774 and PA-1 cell extracts was elevated by increasing the concentration of IFN-gama. IFN-gama caused an increased expression of the important apoptosis-related gene, ICE (interleukin-1beta-converting enzyme) protein in A2774 and PA-1. CONCLUSION: The coordinate induction of IRF-1 and ICE by IFN-gama in ovarian carcinoma cells suggests a functional relationship between these proteins in programmed cell death. The significance of this study is the molecular biologic background of IFN-gama considered as an alternative treatment trial of ovarian cancers.