Examinando por Autor "Acuña-Castillo, Claudio"

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    Macrophage–Neisseria gonorrhoeae Interactions: A Better Understanding of Pathogen Mechanisms of Immunomodulation
    (Frontiers Media S.A., 2018-12) Escobar, Alejandro; Rodas, Paula; Acuña-Castillo, Claudio
    Neisseria gonorrhoeae is a significant health problem worldwide due to multi-drug resistance issues and absence of an effective vaccine. Patients infected with N. gonorrhoeae have not shown a better immune response in successive infections. This might be explained by the fact that N. gonorrhoeae possesses several mechanisms to evade the innate and adaptative immune responses at different levels. Macrophages are a key cellular component in the innate immune response against microorganisms. The current information suggests that gonococcus can hijack the host response by mechanisms that involve the control of macrophages activity. In this mini review, we intend to condense the recent knowledge on the macrophage–N. gonorrhoeae interactions with a focus on strategies developed by gonococcus to evade or to exploit immune response to establish a successful infection. Finally, we discuss the opportunities and challenges of therapeutics for controlling immune manipulation by N. gonorrhoeae. © Copyright © 2018 Escobar, Rodas and Acuña-Castillo.
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    Neisseria gonorrhoeae modulates immunity by polarizing human macrophages to a M2 profile
    (Public Library of Science, 2015-06) Ortiz, María Carolina; Lefimil, Claudia; Rodas, Paula; Vernal, Rolando; Lopez, Mercedes; Acuña-Castillo, Claudio; Imarai, Mónica; Escobar, Alejandro
    Current data suggest that Neisseria gonorrhoeae is able to suppress the protective immune response at different levels, such as B and T lymphocytes and antigen-presenting cells. The present report is focused on gonococcus evasion mechanism on macrophages (MΦ) and its impact in the subsequent immune response. In response to various signals MΦ may undergo classical-M1 (M1-MΦ) or alternative-M2 (M2-MΦ) activation. Until now there are no reports of the gonococcus effects on human MΦ polarization. We assessed the phagocytic ability of monocyte-derived MΦ (MDM) upon gonococcal infection by immunofluorescence and gentamicin protection experiments. Then, we evaluated cytokine profile and M1/ M2 specific-surface markers on MΦ challenged with N. gonorrhoeae and their proliferative effect on T cells. Our findings lead us to suggest N. gonorrhoeae stimulates a M2-MΦ phenotype in which some of the M2b and none of the M1-MΦ-associated markers are induced. Interestingly, N. gonorrhoeae exposure leads to upregulation of a Programmed Death Ligand 1 (PD-L1), widely known as an immunosuppressive molecule. Moreover, functional results showed that N. gonorrhoeae-treated MΦ are unable to induce proliferation of human T-cells, suggesting a more likely regulatory phenotype. Taken together, our data show that N. gonorroheae interferes with MΦ polarization. This study has important implications for understanding the mechanisms of clearance versus long-term persistence of N. gonorroheae infection and might be applicable for the development of new therapeutic strategies. © 2015 Ortiz et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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    Neural reflex regulation of systemic inflammation: potential new targets for sepsis therapy
    (Frontiers Media S.A., 2014) Fernandez, Ricardo; Nardocci, Gino; Navarro, Cristina; Reyes, Edison P.; Acuña-Castillo, Claudio; Cortes, Paula P.
    Sepsis progresses to multiple organ dysfunction due to the uncontrolled release of inflammatory mediators, and a growing body of evidence shows that neural signals play a significant role in modulating the immune response. Thus, similar toall other physiological systems, the immune system is both connected to and regulated by the central nervous system. The efferent arc consists of the activation of the hypothalamic–pituitary–adrenal axis, sympathetic activation, the cholinergic anti-inflammatory reflex, and the local release of physiological neuromodulators. Immunosensory activity is centered on the production of pro-inflammatory cytokines, signals that are conveyed to the brain through different pathways. The activation of peripheral sensory nerves, i.e., vagal paraganglia by the vagus nerve, and carotid body (CB) chemoreceptors by the carotid/sinus nerve are broadly discussed here. Despite cytokine receptor expression in vagal afferent fibers, pro-inflammatory cytokines have no significant effect on vagus nerve activity. Thus, the CB may be the source of immunosensory inputs and incoming neural signals and, in fact, sense inflammatory mediators, playing a protective role during sepsis. Considering that CB stimulation increases sympathetic activity and adrenal glucocorticoids release, the electrical stimulation of arterial chemoreceptors may be suitable therapeutic approach for regulating systemic inflammation
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    Purinergic Signaling as a Regulator of Th17 Cell Plasticity
    (PUBLIC LIBRARY SCIENCE, 2016-06) Fernández, Dominique; Flores-Santibáñez, Felipe; Neira, Jocelyn; Osorio-Barrios, Francisco; Tejón, Gabriela; Nuñez, Sarah; Hidalgo, Yessia; Fuenzalida, Maria Jose; Meza, Daniel; Ureta, Gonzalo; Lladser, Alvaro; Pacheco, Rodrigo; Acuña-Castillo, Claudio; Guixé, Victoria; Quintana, Francisco J.; Bono, Maria Rosa; Rosemblatt, Mario; Sauma, Daniela
    T helper type 17 (Th17) lymphocytes, characterized by the production of interleukin-17 and other pro-inflammatory cytokines, are present in intestinal lamina propria and have been described as important players driving intestinal inflammation. Recent evidence, supporting the notion of a functional and phenotypic instability of Th17 cells, has shown that Th17 differentiate into type 1 regulatory (Tr1) T cells during the resolution of intestinal inflammation. Moreover, it has been suggested that the expression of CD39 ectonucleotidase endows Th17 cells with immunosuppressive properties. However, the exact role of CD39 ectonucleotidase in Th17 cells has not been studied in the context of intestinal inflammation. Here we show that Th17 cells expressing CD39 ectonucleotidase can hydrolyze ATP and survive to ATP-induced cell death. Moreover, in vitro-generated Th17 cells expressing the CD39 ectonucleotidase produce IL-10 and are less pathogenic than CD39 negative Th17 cells in a model of experimental colitis in Rag-/- mice. Remarkably, we show that CD39 activity regulates the conversion of Th17 cells to IL-10-producing cells in vitro, which is abrogated in the presence of ATP and the CD39-specific inhibitor ARL67156. All these data suggest that CD39 expression by Th17 cells allows the depletion of ATP and is crucial for IL-10 production and survival during the resolution of intestinal inflammation.