Diabetes, an inflammatory process: Oxidative Stress and TNF-alpha involved in hepatic complication

Diabetes mellitus (DM) is a serious and growing worldwide health problem and is associated with se- vere acute and chronic complications that negatively influence both quality of life and survival of affected individuals. It is a heterogeneous deregulation of car- bohydrate metabolism. The liver is a central regulator of carbohydrate homeostasis and releases glucose according to metabolic demands. In the last years, the liver injury has been recognized as a major complica- tion of DM. In fact, evidence suggests that in diabetic patients, the mortality rate due to liver cirrhosis is even higher than that due to cardiovascular disease and it has been suggested that there is a two-fold in- creased risk of liver disease in diabetic patients. Among the different types of diabetes, we analyze type 1 dia- betes mellitus as a chronic disorder and an inflam- matory process, which is also associated with in- creased risk of chronic liver injury. Animal models have contributed extensively to the study of diabetes, and it is well established that administration of a unique dose of streptozotocin (STZ) induces insulin- dependent type 1 diabetes mellitus. We analyzed the contribution of Tumor Necrosis Factor alpha (TNF-α) intracellular pathway and oxidative stress in the de- velopment of apoptosis in the liver of streptozotocin- induced diabetic animals. In this review, we describe the role of upstream mediators of the interaction be- tween TNF-α and its receptor, TNF-R1, by assessing the ability of the in vivo treatment with etanercept (TNF-α blocking antibody) to protect against TNF-α- induced apoptosis. Also, we studied the role of iNOS- induction in the TNF-α-induced liver apoptosis by type 1 diabetes, by treatment of diabetic rats with aminoguanidine (selective iNOS inhibitor), which blocked the induction of apoptosis. Interestingly, iNOS inhibition significantly reduced TNF-α levels, evidencing an interaction between TNF-α and iNOS activity. On the other hand, we found that the ad- ministration of antioxidants/hydroxyl radical scaven- gers (Tempol and Desferal) prevented oxidative stress by reducing the effects of hydroxyl radical production and both lipid peroxidation (LPO) levels and apop- tosis. Taken together, our studies support that, at least in part, the hydroxyl radical acts as a reactive inter- mediate, which leads to liver apoptosis in a model of STZ-mediated hyperglycemia. Conclusion and Future: The relevance of the present review is to provide fur- ther knowledge about the mechanisms which may contribute to the disease process in the liver during the course of an inflammatory process as it is type 1 diabetes. Regulation of hepatic TNF-α levels and oxi- dative stress in the diabetic state could be of thera- peutic relevance for the improvement or delay of the hepatic complications linked to chronic hyperglycemia.Fil: Frances, Daniel Eleazar Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Ingaramo, Paola Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Ronco, Maria Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Carnovale, Cristina Ester. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); Argentin

Diethylnitrosamine enhances hepatic tumorigenic pathways in mice fed with high fat diet (Hfd)

Obesity has been implicated in the genesis of metabolic syndromes including insulin resistance and Type 2 Diabetes Mellitus (T2DM). Given the association between T2DM and the risk of hepatocellular carcinoma (HCC), our specific goal was to determine whether the liver of HFD-induced T2DM mice is more sensitive to the carcinogen diethylnitrosamine (DEN), due to a modification of the molecular pathways implicated in the early stages of HCC pathogenesis. C57BL/6 male mice (five-week-old) were divided into 4 groups: C, C + DEN, HFD and HFD + DEN. Mice were euthanized twenty-five weeks after DEN-injection. Livers of HDF-fed mice showed a higher proliferative index than Control groups. In line with this, HFD groups showed an increase of nuclear β-catenin, and interestingly, DEN treatment led to a slight increase in the expression of this protein in HFD group. Based on these results, and to confirm this effect, we analyzed β-catenin target genes, finding that DEN treatment in HFD group led to a significant increase of Vegf, c-myc, c-jun and cyclin D1 expression levels. According to our results, the expression of TCF4 showed to be significantly increased in HFD + DEN vs. HFD. In this regard, the β-catenin/TCF4 complex enhanced its association with pSmads 2/3, as we observed an increase of nuclear Smads expression in HFD + DEN, suggesting a possible role of TGF-β1/Smads signaling pathway in this phenomenon. Our results show that the liver of HFD fed model that resembles early T2DM pathology in mice, is more sensitive to DEN, by inducing both Wnt/β-catenin and TGF β1/Smads tumorigenic pathways.Fil: Arboatti, Ainelén Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Fisiología Experimental. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Fisiología Experimental; ArgentinaFil: Lambertucci, Flavia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Fisiología Experimental. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Fisiología Experimental; ArgentinaFil: Sedlmeier, María Guillermina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Fisiología Experimental. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Fisiología Experimental; ArgentinaFil: Pisani, Gerardo Bruno. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; ArgentinaFil: Monti, Juan Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Fisiología Experimental. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Fisiología Experimental; ArgentinaFil: Alvarez, María de Luján. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Fisiología Experimental. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Fisiología Experimental; ArgentinaFil: Frances, Daniel Eleazar Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Fisiología Experimental. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Fisiología Experimental; ArgentinaFil: Ronco, Maria Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Fisiología Experimental. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Fisiología Experimental; ArgentinaFil: Carnovale, Cristina Ester. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Fisiología Experimental. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Fisiología Experimental; Argentin

Evidence for necrosis, but not apoptosis, in human hepatoma cells with knockdown of mitochondrial aquaporin-8

We previously found that mitochondrial aquaporin-8 (mtAQP8) channels facilitate mitochondrial H2O2 release in human hepatoma HepG2 cells and that their knockdown causes oxidant-induced mitochondrial dysfunction and loss of viability. Here, we studied whether apoptosis or necrosis is involved as the mode of cell death. We confirmed that siRNA-induced mtAQP8 knockdown significantly decreased HepG2 viability by MTT assay, LDH leakage, and trypan blue exclusion test. Analysis of mitochondrial proapoptotic Bax-to-antiapoptotic BclXL ratio, mitochondrial cytochrome c release and caspase-3 activation showed no alterations in mtAQP8-knockdown cells. This indicates a primary mechanism of cell death other than the intrinsic mitochondrial apoptotic pathway. Thus, nuclear staining with DAPI did not reveal any increase of apoptotic features, i.e. chromatin condensation or nuclear fragmentation. Flow cytometry studies after double cell staining with annexin V and propidium iodide confirmed lack of apoptosis and suggested necrosis as the primary mechanism of death in mtAQP8-knockdown HepG2 cells. Necrosis was further supported by the increased nuclear delocalization and extracellular release of the High Mobility Group Box 1 protein. The knockdown of mtAQP8 in another human hepatoma-derived cell line, i.e. HuH-7 cells, also induced necrotic but not apoptotic death. Our data suggest that mtAQP8 knockdown induces necrotic cell death in human neoplastic hepatic cells, a finding that might be relevant to therapeutic strategies against hepatoma cells.Fil: Marchissio, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Frances, Daniel Eleazar Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Carnovale, Cristina Ester. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Marinelli, Raul Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); Argentin

Mitochondrial aquaporin-8 knockdown in human hepatoma HepG2 cells causes ROS-induced mitochondrial depolarization and loss of viability

Human aquaporin-8 (AQP8) channels facilitate the diffusional transport of H2O2 across membranes. Since AQP8 is expressed in hepatic inner mitochondrial membranes, we studied whether mitochondrial AQP8 (mtAQP8) knockdown in human hepatoma HepG2 cells impairs mitochondrial H2O2 release, which may lead to organelle dysfunction and cell death. We confirmed AQP8 expression in HepG2 inner mitochondrial membranes and found that 72 h after cell transfection with siRNAs targeting two different regions of the human AQP8 molecule, mtAQP8 protein specifically decreased by around 60% (pb0.05). Studies in isolated mtAQP8-knockdown mitochondria showed that H2O2 release, assessed by Amplex Red, was reduced by about 45% (pb0.05), an effect not observed in digitonin-permeabilized mitochondria. mtAQP8-knockdown cells showed an increase in mitochondrial ROS, assessed by dichlorodihydrofluorescein diacetate (+120%, pb0.05) and loss of mitochondrial membrane potential (−80%, pb0.05), assessed by tetramethylrhodamine-coupled quantitative fluorescence microscopy. The mitochondria-targeted antioxidant MitoTempol prevented ROS accumulation and dissipation of mitochondrial membrane potential. Cyclosporin A, a mitochondrial permeability transition pore blocker, also abolished the mtAQP8 knockdown-induced mitochondrial depolarization. Besides, the loss of viability in mtAQP8 knockdown cells verified by MTT assay, LDH leakage, and trypan blue exclusion test could be prevented by cyclosporin A. Our data on human hepatoma HepG2 cells suggest that mtAQP8 facilitates mitochondrial H2O2 release and that its defective expression causes ROS-induced mitochondrial depolarization via the mitochondrial permeability transition mechanism, and cell death.Fil: Marchissio, Maria Julia. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Frances, Daniel Eleazar Antonio. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Carnovale, Cristina Ester. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Marinelli, Raul Alberto. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); Argentin

Interferon-a2b and transforming growth factor-b1 treatments on HCC cell lines: are Wnt/b-catenin pathway and Smads signaling connected in hepatocellular carcinoma?

Wnt/b-catenin pathway is often dysregulated in hepatocellular carcinoma (HCC). Activated b-catenin accumulates in the cytosol and nucleus and forms a nuclear complex with TCF/LEF factors like TCF4. Interferon-a (IFN-a) has recently been recognized to harbor therapeutic potential in prevention and treatment of HCC. Transforming Growth Factor-b1 (TGF-b1) is a mediator of apoptosis, exerting its effects via Smads proteins. One mode of interaction between Wnt/b-catenin and TGF-b1/Smads pathways is the association of Smads with b-catenin/TCF4. In this study we analyzed the effects of IFNa2b and TGF-b1 treatments on Wnt/b-catenin pathway, Smads proteins levels, b-catenin/TCF4/Smads interaction and proliferation and apoptotic death in HepG2/C3A and Huh7 cell lines. IFN-a2b and TGFb1 attenuated Wnt/b-catenin signal by decreasing b-catenin and Frizzled7 receptor proteins contents and the interaction of b-catenin with TCF4. Truncated b-catenin form present in C3A cell line also diminished after treatments. Both cytokines declined Smads proteins and their interaction with TCF4. The overall cellular response to cytokines was the decrease in proliferation and increase in apoptotic death. Treatment with Wnt3a, which elevates b-catenin protein levels, also generated the increment of Smads proteins contents when comparing with untreated cells. In conclusion, IFN-a2b and TGF-b1 proved to be effective as modulators of Wnt/b-catenin pathway in HCC cell lines holding both wild-type and truncated b-catenin. Since the inhibition ofb-catenin/TCF4/Smads complexes formation may have a critical role in slowing down oncogenesis, IFN-a2b and TGF-b1 could be useful as potential treatments in patients with HCC.Fil: Ceballos, Maria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; ArgentinaFil: Parody, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; ArgentinaFil: Alvarez, María de Luján. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; ArgentinaFil: Ingaramo, Paola Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; ArgentinaFil: Carnovale, Cristina Ester. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; ArgentinaFil: Carrillo, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentin

Attenuation of the Wnt/b-catenin/TCF pathway by in vivo interferon-a2b (IFN-a2b) treatment in preneoplastic rat livers

Wnt/β-catenin/T cell factor (TCF) pathway is activated in several types of human cancers, promoting cell growth and proliferation. Forkhead box containing protein class O (FOXO) transcription factors compete with TCF for β-catenin binding, particularly under cellular oxidative stress conditions. Contrary to β-catenin/TCF, β-catenin/FOXO promotes the transcription of genes involved in cell cycle arrest and apoptosis. We have previously demonstrated that in vivo interferon-α2b (IFN-α2b) administration induces apoptosis in preneoplastic livers, a mechanism mediated by reactive oxygen species (ROS) and transforming growth factor-β1 (TGF-β1). This study was aimed to assess the status of the Wnt/β-catenin/TCF pathway in a very early stage of rat hepatocarcinogenesis and to further evaluate the effects of in vivo IFN-α2b treatment on it. We demonstrated that the Wnt/β-catenin/TCF pathway is activated in preneoplastic rat livers. More important, in vivo IFN-α2b treatment inhibits Wnt/β-catenin/TCF pathway and promotes programed cell death possibly providing a link with FOXO pathway.Fil: Parody, Juan Pablo. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Alvarez, Maria L.. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Quiroga, Ariel Dario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Frances, Daniel Eleazar Antonio. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Pisani, Gerardo B.. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; ArgentinaFil: Carnovale, Cristina Ester. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Carrillo, Maria Cristina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); Argentin

Ligaria cuneifolia (R. et P.) Tiegh

Ligaria cuneifolia (R. et P.) Tiegh. -Loranthaceae- is a hemiparasitic species that develop on different hosts. it has a wide geographic distribution ranging from Peru to central Argentina and southern Brazil. In Argentina, it is popularly known as " muérdago criollo", "liga" or "liguilla". This species is traditionally used as a hypotensive agent. Due to its morphological similarity, it constitutes the natural substitute for the European mistletoe (Viscum album L.- Santalaceae-). Like other species of the Loranthaceae family, L. cuneifolia is rich in flavonoids, especially flavonols that could be determinant of its pharmacological activity. Aqueous extracts proved to be inhibitors of the proliferation of LB tumor cells, alcoholic extracts have high antioxidant activity, and infusions have the property of lowering plasma cholesterol in patients with a history of hypercholesterolemia. Considering this background information, and the difficulties experienced in its field cultivation, strategies are being developed to produce the metabolites responsible for its different biological activities in in vitro cultures.Fil: Wagner, Marcelo Luis. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacobótanica; ArgentinaFil: Dobrecky, Cecilia Beatriz. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacobótanica; ArgentinaFil: Varela, Beatriz Graciela. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacobótanica; ArgentinaFil: Luquita, Alejandra Nora. Universidad Nacional de Rosario. Facultad de Ciencias Médicas; Argentina. Universidad Nacional de Rosario. Consejo de Investigaciones de la Universidad de Rosario; ArgentinaFil: Carnovale, Cristina Ester. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Fisiología Experimental. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Fisiología Experimental; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Ciencias Fisiológicas; ArgentinaFil: Alvarez, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Maimonides. Facultad de Cs. de la Salud. Carreras de Farmacia y Bioquímica; ArgentinaFil: Ricco, Rafael Alejandro. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacobótanica; Argentin

Effects of proanthocyanidin enriched extract from Ligaria cuneifolia on plasma cholesterol and hemorheological parameters. In vivo and In vitro studies

It was demonstrated that Ligaria cuneifolia (Lc) crude extract increased blood viscosity and decreased plasma cholesterol in rats. In the present study, we analyzed the Lc proanthocyanidin enriched fraction (PLc) to determine if it is capable of altering the hemorheological parameters while diminishing the plasma cholesterol. In vivo studies in adult male Wistar rats, randomized in three groups (n = 6 each one) were performed: 1. Control: saline intraperitoneal (i.p.); 2. PLc 0.6 mg/100 g body weight (b.w.) i.p. and 3. PLc 3 mg/100 g b.w. i.p., every 24 hours during 3 days. In vitro studies: with blood obtained by cardiac puncture, separated in aliquots and incubated with: 1. Saline solution (Control); 2. PLc 0.1 mg/mL, and 3. PLc 1.0 mg/mL, equivalent to doses in vivo experiments. The results demonstrated that in vivo PLc 0.6 and PLc 3 reduced plasma cholesterol (Cho) and LDL-Cho. Neither blood nor plasma viscosity was altered. Decrease of plasma cholesterol could be due to an increase of cholesterol and bile salts excretion leading to an increase of bile flow. In vitro experiments showed a direct interaction of PLc, at high concentration, with the erythrocyte membrane, inducing a switch from discocyte to stomatocyte. Only, PLc without hepatic metabolism produces hemorheological changes. Thus, PLc in vivo might be a pharmacological agent capable of decreasing plasma cholesterol.Fil: Dominighini, Alicia. Universidad Nacional de Rosario. Facultad de Cs.medicas; ArgentinaFil: Ferrero, Mariana Cristina. Universidad Nacional de Rosario. Facultad de Cs.medicas; ArgentinaFil: Crossetti, D.. Universidad Nacional de Rosario. Facultad de Cs.medicas; ArgentinaFil: Ronco, Maria Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Gonzalves, Jose. Universidad Nacional de Rosario. Facultad de Cs.medicas; ArgentinaFil: Urli, Leda. Universidad Nacional de Rosario. Facultad de Cs.bioquimicas y Farmaceuticas. Departamento de Cs.fisiologicas; ArgentinaFil: Wagner, Marcelo Luis. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Gurni, Alberto Angel. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Carnovale, Cristina Ester. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Luquita, Alejandra Nora. Universidad Nacional de Rosario. Facultad de Cs.medicas; Argentin

FoxO3a modulation and promotion of apoptosis by interferon-alfa2b in rat preneoplastic liver

Background: FoxO3a, a member of the FOXO family of transcription factors, is expressed in adult liver and modulates the expression of genes involved in apoptosis. FoxO3a is post-translationally regulated, negatively by PI3K/Akt and MAPK/Erk and positively by oxidative stress/JNK pathways. In previous works, we have demonstrated that interferon-α2b (IFN-α2b) induces apoptosis of hepatic preneoplastic foci through the production of reactive oxygen species (ROS). Aims: To investigate the post-translational signal events triggered by the oxidative stress induced by IFN-α2b and the modulation of FoxO3a transcriptional activity during these events in rat preneoplastic liver. Methods Adult male Wistar rats were subjected to a two-phase model of hepatocarcinogenesis. A group of animals received IFN-α2b and another group received IFN-α2b and ascorbic acid (ASC), by intraperitoneal injection. Lipid peroxidation, immunohistochemistry, immunoblotting, co-immunoprecipitation and sqRT-PCR assays were performed to explore the role of ROS, JNK, Akt, Erk, FoxO3a, β-catenin and PUMA in the IFN-α2b-mediated apoptotic mechanism. Results: In vivo IFN-α2b treatment induced endogenous production of ROS which activated JNK. IFN-α2b blocked the activation of Akt and Erk, avoiding FoxO3a activity repression. Activated JNK was responsible for the nuclear translocation and transcriptional activity of FoxO3a which positively modulated the expression of PUMA, a proapoptotic player. In addition, nuclear FoxO3a competed for the nuclear β-catenin associated to TCF, inhibiting the canonical Wnt signalling pathway. Conclusions: The data presented here propose a model in which in vivo IFN-α2b treatment induces nuclear translocation and transcriptional activity of FoxO3a, triggering the mitochondrial apoptotic pathway in hepatic preneoplastic foci.Fil: Parody, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Ceballos Mancini, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Quiroga, Ariel Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Frances, Daniel Eleazar Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Carnovale, Cristina Ester. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Pisani, Gerardo B.. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; ArgentinaFil: Alvarez, María de Luján. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); ArgentinaFil: Carrillo, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentin