Gene Expression Control by Glucocorticoid Receptors during Innate Immune Responses

Glucocorticoids (GCs) are potent anti-inflammatory compounds that have been extensively used in clinical practice for several decades. GC's effects on inflammation are generally mediated through GC receptors (GRs). Signal transduction through these nuclear receptors leads to dramatic changes in gene expression programs in different cell types, typically due to GR binding to DNA or to transcription modulators. During the last decade, the view of GCs as exclusive anti-inflammatory molecules has been challenged. GR negative interference in pro-inflammatory gene expression was a landmark in terms of molecular mechanisms that suppress immune activity. In fact, GR can induce varied inhibitory molecules, including a negative regulator of Toll-like receptors pathway, or subject key transcription factors, such as NF-kappa B and AP-1, to a repressor mechanism. In contrast, the expression of some acute-phase proteins and other players of innate immunity generally requires GR signaling. Consequently, GRs must operate context-dependent inhibitory, permissive, or stimulatory effects on host defense signaling triggered by pathogens or tissue damage. This review aims to disclose how contradictory or comparable effects on inflammatory gene expression can depend on pharmacological approach (including selective GC receptor modulatorsSEGRMs), cell culture, animal treatment, or transgenic strategies used as models. Although the current view of GR-signaling integrated many advances in the field, some answers to important questions remain elusive.Fundacao de Amparo a Pesquisa do Estado de Sao PauloConselho National de Desenvolvimento Cientifico e TecnolOgicoUniv Fed Sao Paulo, Escola Paulista Med, Dept Biochem, Sao Paulo, BrazilSanta Casa Sao Paulo Med Sch, Dept Physiol Sci, Sao Paulo, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Dept Biochem, Sao Paulo, BrazilFAPESP: 2007/53732-8CNPq: 484869/2012-4Web of Scienc

Study of cellular and molecular mechanisms related to the neurodegenerative process of Hunting disease

Introdução: Alterações no tamponamento do cálcio citosólico (Ca+2 c) podem levar à desordens neurodegenerativas como a Doença de Huntington (DH). Vários mecanismos estão relacionados esses processos tais como a excitotoxicidade, o estresse oxidativo e as interações da proteína huntintina mutante (mhtt) com outras proteínas como a transglutaminase 2 (TG2). Essas alterações podem estar relacionadas com a ativação de mecanismos de morte celular ou autofagia. Objetivo: O objetivo deste projeto foi investigar os mecanismos celulares e moleculares envolvidos no processo de neurodegeneração da DH tais como alterações dos níveis de Ca+2 c relacionados com o transporte de Ca+2 mitocondrial (Ca+2 m) e reticular (Ca+2 RE), disfunção mitocondrial e morte celular, em três modelos experimentais: a) animais transgênicos da linhagem R6/1; b) linfoblastos provenientes de pacientes com DH; c) células MEFs (fibroblastos) normais e knock-outs para a TG2, na presença ou ausência da mhtt. Resultados e Conclusões: Nos camundongos transgênicos R6/1 houve um aumento significante do Ca+2 c em relação aos controles aos 9 meses de idade. Essa alteração parece ser devido a um aumento da liberação do Ca+2 m, do estresse oxidativo, do potencial de membrana mitocondrial (DYm) e do consumo de oxigênio. Os transgênicos não apresentaram diferença quanto à SDH, muito embora haja um aumento desta com o envelhecimento. Além disso, os linfoblastos de pacientes com DH apresentaram alterações do Ca+2 m e do Ca+2 RE, bem como um aumento na taxa de células autofágicas. Por outro lado, nas células de fibroblastos de camundongos embrionários (MEFs), a presença de mhtt parece não afetar a homeostase celular de Ca2+. A ausência da TG2 nestas células, influenciou não somente os níveis de Ca2+ c como também protegeu as células contra autofagia, mesmo na presença de mhtt

Study of cellular and molecular mechanisms related to the neurodegenerative process of Hunting disease

Introdução: Alterações no tamponamento do cálcio citosólico (Ca+2 c) podem levar à desordens neurodegenerativas como a Doença de Huntington (DH). Vários mecanismos estão relacionados esses processos tais como a excitotoxicidade, o estresse oxidativo e as interações da proteína huntintina mutante (mhtt) com outras proteínas como a transglutaminase 2 (TG2). Essas alterações podem estar relacionadas com a ativação de mecanismos de morte celular ou autofagia. Objetivo: O objetivo deste projeto foi investigar os mecanismos celulares e moleculares envolvidos no processo de neurodegeneração da DH tais como alterações dos níveis de Ca+2 c relacionados com o transporte de Ca+2 mitocondrial (Ca+2 m) e reticular (Ca+2 RE), disfunção mitocondrial e morte celular, em três modelos experimentais: a) animais transgênicos da linhagem R6/1; b) linfoblastos provenientes de pacientes com DH; c) células MEFs (fibroblastos) normais e knock-outs para a TG2, na presença ou ausência da mhtt. Resultados e Conclusões: Nos camundongos transgênicos R6/1 houve um aumento significante do Ca+2 c em relação aos controles aos 9 meses de idade. Essa alteração parece ser devido a um aumento da liberação do Ca+2 m, do estresse oxidativo, do potencial de membrana mitocondrial (DYm) e do consumo de oxigênio. Os transgênicos não apresentaram diferença quanto à SDH, muito embora haja um aumento desta com o envelhecimento. Além disso, os linfoblastos de pacientes com DH apresentaram alterações do Ca+2 m e do Ca+2 RE, bem como um aumento na taxa de células autofágicas. Por outro lado, nas células de fibroblastos de camundongos embrionários (MEFs), a presença de mhtt parece não afetar a homeostase celular de Ca2+. A ausência da TG2 nestas células, influenciou não somente os níveis de Ca2+ c como também protegeu as células contra autofagia, mesmo na presença de mhtt.TEDEBV UNIFESP: Teses e dissertaçõe

A link between preeclampsia and psychiatric disorders: a behavioral analysis in an animal model of intrauterine hypoxia

Introduction: The association between preeclampsia (PE), known as a disorder of pregnancy characterized by the onset of systemic arterial hypertension, and the promotion of neurodevelopmental disorders has been hypothesized by several studies. Indeed, it is believed that multifactorial psychiatric conditions may arise after a compromised anatomical and functional brain development due to low oxygen levels. However, a solid relation between intrauterine hypoxia and potential subsequent neurodevelopmental deficits remains unknown. Therefore, studies in animal models of PE become essential for understanding this specific cause and effect from a behavioral perspective. The aim of this study was to evaluate behavioral alterations in 2-month-old (P60) male rats from females Wistars treated with L-NAME, a hypertensive agent that inhibits nitric oxide synthase (NOS). In addition, we sought to identify a possible protective effect of Sildenafil Citrate (CS), a potent vasodilator, against PE. Methodology: Firstly, pregnant female Wistar rats were treated by gavage, daily, from the 1st to the 18th day of pregnancy (DP) with L-NAME (50 mg/kg) and with CS (10 mg/kg) from the 7th to the 18th DP. Control animals were treated with similar volumes of pure water. The pups were then divided accordingly: 1) Control; 2) L-NAME; 3) CS; 4) L-NAME+CS. The behavioral tests were performed in P60 animals; the male rats were subjected to open field, social interaction, sucrose preference and contextual fear conditioning tests. The results were analyzed by One Way ANOVA with Bonferroni’s post-hoc. Data are presented as mean ± SD (in % of Control group). Results: As expected, the SBP (Systolic Blood Pressure) was significantly elevated in L-NAME treated rats than in controls (149.40 ± 15.45 versus 100.40 ± 2.37, p<0.0001). Still, it was possible to notice a reduction in SBP after the concomitant administration of L-NAME and CS in comparison to L-NAME group (117.00 ± 17.79 versus 149.40 ± 15.45, p<0.0001). No significant differences were verified among all groups evaluated in the open field or social interaction tests (p>0.05). However, the L-NAME group showed a decrease in sucrose preference test (64.12 ± 10.98, p<0.05). Lastly, the results of contextual fear conditioning test pointed towards a reduction in freezing time in L-NAME animals in comparison to the Control group (33.89 ± 33.96 versus 193.00 ± 122.00, p<0.01). Discussion: L-NAME administration induces an increase in SBP that possibly can lead to intrauterine hypoxia and may explain anhedonia and cognitive impairments observed in preeclampsia-like rats. Curiously, such phenotypes are important features of several neurodevelopmental disorders, like Intellectual Disability, Autism Spectrum Disorder and Attention Deficit Hyperactivity Disorder, as well as the prodromal phase of Schizophrenia. Our study also indicates that CS administration reverses part of the behavioral alterations observed after PE. Conclusion: Increased SBP during pregnancy promotes intrauterine hypoxia, which seems to be a crucial factor in triggering behavioral alterations that are consistent with neurodevelopmental disorders

Mitochondrial calcium, oxidative stress and apoptosis in a neurodegenerative disease model induced by 3-nitropropionic acid

Intracellular calcium homeostasis is important for cell survival. However, increase in mitochondrial calcium (Ca-m(2+)) induces opening of permeability transition pore (PTP), mitochondrial dysfunction and apoptosis. Since alterations of intracellular Ca2+ and reactive oxygen species (ROS) generation are involved in cell death, they might be involved in neurodegenerative processes such as Huntington's disease (HD). HD is characterized by the inhibition of complex II of respiratory chain and increase in ROS production. in this report, we studied the correlation between the inhibitor of the complex II, 3-nitropropionic acid (3NP), Ca2+ metabolism, apoptosis and behavioural alterations. We showed that 3NP (1 mM) is able to release Ca-m(2+), as neither Thapsigargin (TAP, 2 muM) nor free-calcium medium affected its effect. PTP inhibitors and antioxidants inhibited this process, suggesting an increase in ROS generation and PTP opening. in addition, 3NP (0.1 mM) also induces apoptotic cell death. Behavioural changes in animals treated with 3NP (20 mg/kg/day for 4 days) were also attenuated by pre- and co-treatment with vitamin E (VE, 20 mg/kg/day). Taken together, our results show that complex II inhibition could involve Ca-m(2+) release, oxidative stress and cell death that may precede motor alterations in neurodegenerative processes such as HD