Browsing by Author "Herrada, Andres A."

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    Aldosterone Promotes Autoimmune Damage by Enhancing Th17-Mediated Immunity
    (AMER ASSOC IMMUNOLOGISTS, 2010) Herrada, Andres A.; Contreras, Francisco J.; Marini, Natacha P.; Amador, Cristian A.; Gonzalez, Pablo A.; Cortes, Claudia M.; Riedel, Claudia A.; Carvajal, Cristian A.; Figueroa, Fernando; Michea, Luis F.; Fardella, Carlos E.; Kalergis, Alexis M.
    Excessive production of aldosterone leads to the development of hypertension and cardiovascular disease by generating an inflammatory state that can be promoted by T cell immunity. Because nature and intensity of T cell responses is controlled by dendritic cells (DCs), it is important to evaluate whether the function of these cells can be modulated by aldosterone. In this study we show that aldosterone augmented the activation of CD8(+) T cells in a DC-dependent fashion. Consistently, the mineralocorticoid receptor was expressed by DCs, which showed activation of MAPK pathway and secreted IL-6 and TGF-beta in response to aldosterone. In addition, DCs stimulated with aldosterone impose a Th17 phenotype to CD4(+) T cells, which have recently been associated with the promotion of inflammatory and autoimmune diseases. Accordingly, we observed that aldosterone enhances the progression of experimental autoimmune encephalomyelitis, an autoimmune disease promoted by Th17 cells. In addition, blockade of the mineralocorticoid receptor prevented all aldosterone effects on DCs and attenuated experimental autoimmune encephalomyelitis development in aldosterone-treated mice. Our data suggest that modulation of DC function by aldosterone enhances CD8(+) T cell activation and promotes Th17-polarized immune responses, which might contribute to the inflammatory damage leading to hypertension and cardiovascular disease. The Journal of Immunology, 2010, 184: 191-202.
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    Haem oxygenase 1 expression is altered in monocytes from patients with systemic lupus erythematosus
    (WILEY, 2012) Herrada, Andres A.; Llanos, Carolina; Mackern Oberti, Juan P.; Carreno, Leandro J.; Henriquez, Carla; Gomez, Roberto S.; Gutierrez, Miguel A.; Anegon, Ignacio; Jacobelli, Sergio H.; Kalergis, Alexis M.
    Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by multiple functional alterations affecting immune cells, such as B cells, T cells, dendritic cells (DCs) and monocytes. During SLE, the immunogenicity of monocytes and DCs is significantly up-regulated, promoting the activation of self-reactive T cells. Accordingly, it is important to understand the contribution of these cells to the pathogenesis of SLE and the mechanisms responsible for their altered functionality during disease. One of the key enzymes that control monocyte and DC function is haem oxygenase-1 (HO-1), which catalyses the degradation of the haem group into biliverdin, carbon monoxide and free iron. These products possess immunosuppressive and anti-inflammatory capacities. The main goal of this work was to determine HO-1 expression in monocytes and DCs from patients with SLE and healthy controls. Hence, peripheral blood mononuclear cells were obtained from 43 patients with SLE and 30 healthy controls. CD14+ monocytes and CD4+ T cells were sorted by FACS and HO-1 expression was measured by RT-PCR. In addition, HO-1 protein expression was determined by FACS. HO-1 levels in monocytes were significantly reduced in patients with SLE compared with healthy controls. These results were confirmed by flow cytometry. No differences were observed in other cell types, such as DCs or CD4+ T cells, although decreased MHC-II levels were observed in DCs from patients with SLE. In conclusion, we found a significant decrease in HO-1 expression, specifically in monocytes from patients with SLE, suggesting that an imbalance of monocyte function could be partly the result of a decrease in HO-1 expression.
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    Modulation of nuclear factor-kappa B activity can influence the susceptibility to systemic lupus erythematosus
    (WILEY-BLACKWELL PUBLISHING, INC, 2009) Kalergis, Alexis M.; Iruretagoyena, Mirentxu I.; Barrientos, Magaly J.; Gonzalez, Pablo A.; Herrada, Andres A.; Leiva, Eduardo D.; Gutierrez, Miguel A.; Riedel, Claudia A.; Bueno, Susan M.; Jacobelli, Sergio H.
    P>Autoimmune diseases, such as systemic lupus erythematosus (SLE), result from deficiencies in self-antigen tolerance processes, which require regulated dendritic cell (DC) function. In this study we evaluated the phenotype of DCs during the onset of SLE in a mouse model, in which deletion of the inhibitory receptor Fc gamma RIIb leads to the production of anti-nuclear antibodies and glomerulonephritis. Splenic DCs from Fc gamma RIIb-deficient mice suffering from SLE showed increased expression of co-stimulatory molecules. Furthermore, diseased mice showed an altered function of the nuclear factor-kappa B (NF-kappa B) transcription factor, which is involved in DC maturation. Compared with healthy animals, expression of the inhibitory molecule I kappa B-alpha was significantly decreased in mice suffering from SLE. Consistently, pharmacological inhibition of NF-kappa B activity in Fc gamma RIIb-deficient mice led to reduced susceptibility to SLE and prevented symptoms, such as anti-nuclear antibodies and kidney damage. Our data suggest that the occurrence of SLE is significantly influenced by alterations of NF-kappa B function, which can be considered as a new therapeutic target for this disease.