Anti-inflammatory and antioxidant properties of a new arylidene-thiazolidinedione in macrophages.

Thiazolidinediones (TZDs) are a class of drugs used for treatment of type 2 diabetes. However, the therapy with currently available TDZs (e.g. rosiglitazone) is associated with important side effects, such as edema and weight gain, suggesting that the investigation of alternative TZDs with better pharmacological properties is warranted. In this study, we investigated both anti-inflammatory and antioxidant properties of a new chemically modified TZD, the arylidene-thiazolidinedione 5-(4-methanesulfonyl-benzylidene)-3-(4-nitrobenzyl)-thiazolidine-2,4-dione (SF23), and compared the results to those obtained with rosiglitazone. We found that our SF23 displays a weaker affinity for PPARγ, up-regulating in a lower magnitude the expression of both PPARγ and CD36 compared to rosiglitazone. In lipopolysaccharide (LPS)-stimulated macrophages, SF23 decreased nitrite production and attenuated the mRNA expression of both iNOS and COX-2. These anti-inflammatory effects were comparable to those obtained with rosiglitazone. Interestingly, SF23, but not rosiglitazone, prevented LPS-induced mitochondrial membrane hyperpolarization, apoptosis, reactive oxygen species (ROS) generation, and the expression of NADPH oxidase subunits, Nox1 and Nox2. In addition, in macrophages from Nrf2⁻/⁻ mice, SF23 protected against LPSinduced cellular death and ROS production, whereas rosiglitazone was only able to protect normal Nrf2⁺/⁺ cells against oxidative injury, suggesting that, unlike rosiglitazone, the antioxidant activity of SF23 might be Nrf2-independent. Finally, in macrophages exposed to high concentrations of glucose, SF23 induced significant increases in the mRNA expression of glucose transporters, insulin receptor substrate and mitoNEET. Altogether, our data indicate that our new chemically modified TDZ displays similar anti-inflammatory properties, but superior antioxidant effects on the LPS-stimulated macrophages compared to rosiglitazone.

Electronegative LDL induction of apoptosis in macrophages: involvement of Nrf2.

The aim of this study was to determine the apoptotic pathways and mechanisms involved in electronegative LDL [LDL(-)]-induced apoptosis in RAW 264.7 macrophages and the role of Nrf2 in this process. Incubation of RAW 264.7 macrophages with LDL(-) for 24 h resulted in dose-dependent cell death. Activated caspases were shown to be involved in the apoptosis induced by LDL(-); incubation with the broad caspase inhibitor z-VAD prevented apoptosis in LDL(-)-treated cells. CD95 (Fas), CD95 ligand (FasL), CD36 and the tumor necrosis factor (TNF) ligand Tnfsf10 were overexpressed in LDL(-)-treated cells. However, Bax, Bcl-2 and Mcl-1 protein levels remained unchanged after LDL(-) treatment. LDL(-) promoted hyperpolarization of the mitochondrial membrane, elevated reactive oxygen species (ROS) production and translocation of Nrf2 to the nucleus, a process absent in cells treated with native LDL. Elicited peritoneal macrophages from Nrf2-deficient mice exhibited an elevated apoptotic response after challenge with LDL(-), together with an increase in the production of ROS in the absence of alterations in CD36 expression. These results provide evidence that CD36 expression induced by LDL(-) is Nrf2-dependent. Also, it was demonstrated that Nrf2 acts as a compensatory mechanism of LDL(-)-induced apoptosis in macrophages.

[Changes in distribution and isoenzymatic expression of protein kinase C in B lymphocytes induced by alloantigenic stimulation]. / Cambios en la distribución y expresión iosenzimática de proteína quinasa C en linfocitos B por estimulación aloantigénica.

Protein kinase C comprises a family of distinct isoenzymes that are involved in signal transduction pathway triggered by activation of membrane receptor. These isoenzymes differ in their tissue distribution, activation requirements and substrate specificity. Recent reports have shown the regulation of PKC-isoenzymes expression in physiological and pathological models. Recently, we shown PKC participation in B cells allogeneic response to intact cells and solubilized alloantigen. Here, alloimmunization influence upon PKC isoforms expression on murine B cells was analyzed. Our data indicates that PKC beta is the main isoform expressed on B cells with a lesser amount of alpha, epsilon and zeta and a very small amount of delta isoform. When analyzing B cells from alloimmunized mice we observed an increment of isoforms a and e and a decrease of the beta isoforms while increasing the number of immunizations. An increase of membrane bound PKC enzyme was also observed. Furthermore with increasing number of immunizations a decrease in LPS induce proliferation was found. In contrary, while normal B cells showed non proliferation when stimulated with solubilized alloantigen, they displayed a strong proliferation when they were obtained from animals with 5-6 alloimmunizations. This results shown that alloimmunization induces changes in the distribution and expression of PKC isoenzymes that are correlated to changes in the biological response triggered by B cell stimulation.

Cambios en la distribucion y expresion eosenzimatica de proteina quinasa C en linfocitos B por estimulacion aloantigenica / Changes in distribution and isoenzimatic expression of protein kinase C in B cells by alloantigenic stimulation

La proteína qinasa C (PKC) comprende una familia de isoenzimas involucradas en la transducción de señales vía la estimulación de proteínas de membrana. Estas isoenzimas difieren en su distribución tisular, requerimientos de activación y especificidad de sustrato. Recientes estudios muestran la regulación en la expresión de isoformas de PKC, en diferentes situaciones fisiológicas y patológicas. En un trabajo previo demostramos la participación de la PKC en la respuesta de células B a células alogeneicas intactas y a aloantígeno solubilizado. En el presente estudio se analizó la influencia de la aloinmunización sobre la expresión de isoformas de PKC en células B, De acuerdo a nuestros resultados las células B expresan principalmente la isoforma ß, em menor proporción las O, ÷ y y en muy poca cantidad la U. El análisis realizado con linfocitos de animales previamente inmunizados indicó que a medida que aumenta el número de inmunizaciones, aumenta la expresión de las isoformas O y ÷ y disminuye la expresión de la ß. Además se observó una mayor proporción de enzima unida a membrana. Por otro lado, a medida que aumenta el número de proliferativa al lipopolisacárido (LPS). En cambio, la falta de respuesta proliferativa frente al aloantígeno solubilizado observada para células B sin inmunizar pasa a ser francamente proliferativa para células con 5-6 inmunizaciones. Estos resultados indican que la aloinmunización induce cambios en la expresión y distribución de las isoformas de la enzima que se correlacionan con cambios en la respuesta biológica obtenida por estimulación (AU)

Cambios en la distribucion y expresion eosenzimatica de proteina quinasa C en linfocitos B por estimulacion aloantigenica / Changes in distribution and isoenzimatic expression of protein kinase C in B cells by alloantigenic stimulation

La proteína qinasa C (PKC) comprende una familia de isoenzimas involucradas en la transducción de señales vía la estimulación de proteínas de membrana. Estas isoenzimas difieren en su distribución tisular, requerimientos de activación y especificidad de sustrato. Recientes estudios muestran la regulación en la expresión de isoformas de PKC, en diferentes situaciones fisiológicas y patológicas. En un trabajo previo demostramos la participación de la PKC en la respuesta de células B a células alogeneicas intactas y a aloantígeno solubilizado. En el presente estudio se analizó la influencia de la aloinmunización sobre la expresión de isoformas de PKC en células B, De acuerdo a nuestros resultados las células B expresan principalmente la isoforma ß, em menor proporción las Ó, õ y y en muy poca cantidad la Ù. El análisis realizado con linfocitos de animales previamente inmunizados indicó que a medida que aumenta el número de inmunizaciones, aumenta la expresión de las isoformas Ó y õ y disminuye la expresión de la ß. Además se observó una mayor proporción de enzima unida a membrana. Por otro lado, a medida que aumenta el número de proliferativa al lipopolisacárido (LPS). En cambio, la falta de respuesta proliferativa frente al aloantígeno solubilizado observada para células B sin inmunizar pasa a ser francamente proliferativa para células con 5-6 inmunizaciones. Estos resultados indican que la aloinmunización induce cambios en la expresión y distribución de las isoformas de la enzima que se correlacionan con cambios en la respuesta biológica obtenida por estimulación

Cambios en la distribución y expresión iosenzimática de proteína quinasa C en linfocitos B por estimulación aloantigénica. / [Changes in distribution and isoenzymatic expression of protein kinase C in B lymphocytes induced by alloantigenic stimulation]

Protein kinase C comprises a family of distinct isoenzymes that are involved in signal transduction pathway triggered by activation of membrane receptor. These isoenzymes differ in their tissue distribution, activation requirements and substrate specificity. Recent reports have shown the regulation of PKC-isoenzymes expression in physiological and pathological models. Recently, we shown PKC participation in B cells allogeneic response to intact cells and solubilized alloantigen. Here, alloimmunization influence upon PKC isoforms expression on murine B cells was analyzed. Our data indicates that PKC beta is the main isoform expressed on B cells with a lesser amount of alpha, epsilon and zeta and a very small amount of delta isoform. When analyzing B cells from alloimmunized mice we observed an increment of isoforms a and e and a decrease of the beta isoforms while increasing the number of immunizations. An increase of membrane bound PKC enzyme was also observed. Furthermore with increasing number of immunizations a decrease in LPS induce proliferation was found. In contrary, while normal B cells showed non proliferation when stimulated with solubilized alloantigen, they displayed a strong proliferation when they were obtained from animals with 5-6 alloimmunizations. This results shown that alloimmunization induces changes in the distribution and expression of PKC isoenzymes that are correlated to changes in the biological response triggered by B cell stimulation.