Dexamethasone attenuates inflammatory-mediated suppression of ß2-adrenoceptor expression in rat primary mixed glia.

ß2-adrenoceptors are G-protein coupled receptors expressed on both astrocytes and microglia that play a key role in mediating the anti-inflammatory actions of noradrenaline in the CNS. Here the effect of an inflammatory stimulus (LPS + IFN-γ) was examined on glial ß2-adrenoceptor expression and function. Exposure of glia to LPS + IFN-γ decreased ß2-adrenoceptor mRNA and agonist-stimulated production of the intracellular second messenger cAMP. Pre-treatment with the synthetic glucocorticoid and potent anti-inflammatory agent dexamethasone prevented the LPS + IFN-γ-induced suppression of ß2-adrenoceptor mRNA expression. These results raise the possibility that inflammation-mediated ß2-adrenoceptor downregulation in glia may dampen the innate anti-inflammatory properties of noradrenaline in the CNS.

Effects of match play and training on circulating S100B concentration in professional rugby players.

OBJECTIVES: Examine the effects of match play and a season of training on serum S100B concentration in male professional rugby players. To assess the influence of contact play, values were compared with age- and fitness-matched athletes not involved in a contact sport. METHODS: Over a 2-year period, blood samples were collected from 38 players in pre-season, end of season, and post-matches (within 2 h). A control group of rowers (n = 15) was assessed pre- and post-training. RESULTS: S100B concentration changed significantly over a season (χ2(2) = 17.636, p < 0.0005); post-match values were significantly increased from baseline (early season: Z = -3.670, p < 0.0005; late season: Z = -3.408, p = 0.001). There were no significant differences in S100B concentrations between pre-seasons (Z = -1.601, p = 0.109), or between end of season and subsequent pre-season (Z = -0.330, p = 0.741). While comparable at baseline, samples taken from rugby players post-match were significantly increased compared with samples taken from rowers post-exercise (U = 47.0, p < 0.0005). CONCLUSION: Exercise has a significant effect on circulating S100B in elite male athletes, with levels following rugby matches significantly higher than following non-contact sport. This elevation in S100B is temporary, with a return to baseline values after periods without play.

Nanoparticle-induced neuronal toxicity across placental barriers is mediated by autophagy and dependent on astrocytes.

The potential for maternal nanoparticle (NP) exposures to cause developmental toxicity in the fetus without the direct passage of NPs has previously been shown, but the mechanism remained elusive. We now demonstrate that exposure of cobalt and chromium NPs to BeWo cell barriers, an in vitro model of the human placenta, triggers impairment of the autophagic flux and release of interleukin-6. This contributes to the altered differentiation of human neural progenitor cells and DNA damage in the derived neurons and astrocytes. Crucially, neuronal DNA damage is mediated by astrocytes. Inhibiting the autophagic degradation in the BeWo barrier by overexpression of the dominant-negative human ATG4BC74A significantly reduces the levels of DNA damage in astrocytes. In vivo, indirect NP toxicity in mice results in neurodevelopmental abnormalities with reactive astrogliosis and increased DNA damage in the fetal hippocampus. Our results demonstrate the potential importance of autophagy to elicit NP toxicity and the risk of indirect developmental neurotoxicity after maternal NP exposure.

Induction of protein citrullination and auto-antibodies production in murine exposed to nickel nanomaterials.

Citrullination, or the post-translational deimination of polypeptide-bound arginine, is involved in several pathological processes in the body, including autoimmunity and tumorigenesis. Recent studies have shown that nanomaterials can trigger protein citrullination, which might constitute a common pathogenic link to disease development. Here we demonstrated auto-antibody production in serum of nanomaterials-treated mice. Citrullination-associated phenomena and PAD levels were found to be elevated in nanomaterials -treated cell lines as well as in the spleen, kidneys and lymph nodes of mice, suggesting a systemic response to nanomaterials injection, and validated in human pleural and pericardial malignant mesothelioma (MM) samples. The observed systemic responses in mice exposed to nanomaterials support the evidence linking exposure to environmental factors with the development of autoimmunity responses and reinforces the need for comprehensive safety screening of nanomaterials. Furthermore, these nanomaterials induce pathological processes that mimic those observed in Pleural MM, and therefore require further investigations into their carcinogenicity.

The ß2-adrenoceptor agonist clenbuterol reduces the neuroinflammatory response, neutrophil infiltration and apoptosis following intra-striatal IL-1ß administration to rats.

OBJECTIVES: Clenbuterol is a brain penetrant ß2-adrenoceptor agonist with anti-inflammatory and putative neuroprotective properties. In the present investigation, the effect of clenbuterol was assessed in a rat model of acute brain injury induced by intra-striatal administration of the pro-inflammatory cytokine IL-1ß. METHODS: Clenbuterol (0.5 mg/kg; i.p.) was administered one hour prior to stereotactically delivered IL-1ß (100 ng) into the striatum. Four hours postinjection, rats were anesthetized, blood samples were collected for circulating cytokine and chemokine analysis, and the ipsilateral striatum and liver tissue were harvested for mRNA expression analysis of target genes. RESULTS: Intrastriatal IL-1ß provoked an inflammatory response with increased expression of IL-1ß and the pro-inflammatory cytokine TNF-α. TNF-α expression was also increased in the liver and circulating concentrations of the chemokine cytokine-induced neutrophil chemoattractant 1 (CINC-1) were raised in response to intrastriatal IL-1ß administration. The striatal response was accompanied by NFκB activation and 24 hours postinjection, increased immunoreactivity of the neutrophil marker MBS-2, indicative of cell infiltration and increased TUNEL staining, a cell marker of apoptosis. Treatment with clenbuterol attenuated all IL-1ß-induced changes in the striatum including MBS-2 immunoreactivity and TUNEL + staining. Clenbuterol also attenuated IL-1ß-induced expression of TNF-α in the liver and the increase in circulating CINC-1 concentrations. CONCLUSIONS: The results provide evidence that clenbuterol elicits anti-inflammatory effects, suppresses the peripheral acute phase response and reduces the infiltration of neutrophils and apoptotic response to acute IL-1ß-induced brain injury. Suppression of both the central and peripheral response following clenbuterol administration may contribute to its protective properties following brain injury.

Inhibition of matrix metalloproteinase-9 by a barbiturate-nitrate hybrid ameliorates dextran sulphate sodium-induced colitis: effect on inflammation-related genes.

BACKGROUND AND PURPOSE: Matrix metalloproteinase-9 (MMP-9) is up-regulated in ulcerative colitis and implicated in the pathology of the disease. In this study, we have examined the effects of a barbiturate-based MMP inhibitor incorporating a nitric oxide donor/mimetic group (dinitrate-barbiturate) on the intestinal injury induced by dextran sulphate sodium (DSS). EXPERIMENTAL APPROACH: In vivo experiments were carried out using male Wistar rats given 5% DSS ad libitum in drinking water. The dinitrate-barbiturate, non-nitrate equivalent, nitrate side chains alone or vehicle were administered rectally, twice daily. MMP-9 release was measured by gelatin zymography, and analysis of gene expression was carried out using RT-qPCR. TaqMan low density arrays were used to evaluate the expression of 91 inflammatory genes in the rat colon. KEY RESULTS: The dinitrate-barbiturate inhibited the induction and activity of MMP-9 during DSS colitis in the rat. This occurred in association with significant reductions in the colitic response to DSS as assessed by an established clinical disease activity index and a pathological colitis grade score. The compound modified expression rates of numerous inflammation-related genes in the colon. CONCLUSIONS AND IMPLICATIONS: This study demonstrated the efficacy of the dinitrate-barbiturate in DSS-induced colitis. Therefore, barbiturate-nitrate hybrids may be developed as a promising anti-inflammatory approach to the treatment of inflammatory bowel disease.

First-in-class thyrotropin-releasing hormone (TRH)-based compound binds to a pharmacologically distinct TRH receptor subtype in human brain and is effective in neurodegenerative models.

JAK4D, a first-in-class thyrotropin-releasing hormone (TRH)-based compound, is a prospective therapeutic candidate offering a multifaceted approach to treating neurodegeneration and other CNS conditions. The purpose of these studies was to determine the ability of JAK4D to bind to TRH receptors in human brain and to evaluate its neuropharmacological effects in neurodegenerative animal models. Additionally, JAK4D brain permeation was examined in mouse, and initial toxicology was assessed in vivo and in vitro. We report that JAK4D bound selectively with nanomolar affinity to native TRH receptors in human hippocampal tissue and showed for the first time that these receptors are pharmacologically distinct from TRH receptors in human pituitary, thus revealing a new TRH receptor subtype which represents a promising neurotherapeutic target in human brain. Systemic administration of JAK4D elicited statistically significant and clinically-relevant neuroprotective effects in three established neurodegenerative animal models: JAK4D reduced cognitive deficits when administered post-insult in a kainate (KA)-induced rat model of neurodegeneration; it protected against free radical release and neuronal damage evoked by intrastriatal microdialysis of KA in rat; and it reduced motor decline, weight loss, and lumbar spinal cord neuronal loss in G93A-SOD1 transgenic Amyotrophic Lateral Sclerosis mice. Ability to cross the blood-brain barrier and a clean initial toxicology profile were also shown. In light of these findings, JAK4D is an important tool for investigating the hitherto-unidentified central TRH receptor subtype reported herein and an attractive therapeutic candidate for neurodegenerative disorders.

C-reactive protein predicts fatigue independently of depression in breast cancer patients prior to chemotherapy.

Heightened inflammatory activity has been proposed as a mechanism for the development of cancer-related fatigue (CRF), a common and distressing condition that can negatively affect quality of life. Inflammation is also implicated in the pathogenesis of depression, and depression is a strong predictor of CRF. Thus, the role of the pro-inflammatory cytokine network in CRF may be mediated by depression or both conditions may share similar underlying physiological processes. The current study investigated associations between fatigue, depression and inflammatory cytokine (IFN-γ, IL-6, TNF-α) and CRP concentrations, as well as kynurenine pathway (KP) activation, in 61 breast cancer patients prior to chemotherapy. Changes in inflammatory markers and KP activation over time were also explored, and associations with changes in fatigue and depression were examined. Higher levels of CRP were significantly correlated with fatigue and depression before chemotherapy; nevertheless, CRP predicted fatigue independently of depression. Although greater kynurenine concentrations were associated with increased immune activation, there was no evidence that the KP played a role in fatigue or depression. Furthermore, no relationships emerged between either fatigue or depression and IFN-γ, IL-6, or TNF-α before chemotherapy. Nevertheless, kynurenine levels pre- and post-treatment significantly predicted changes in depression, suggesting that heightened KP activation may contribute to depressive symptoms in patients treated for cancer. In addition, IL-6 significantly covaried with fatigue. These preliminary findings provide some support for the idea that low-grade inflammation contributes to the development of CRF, independently of depression; however, there was no evidence that this is mediated by KP activity.

Ischemic brain injury: a consortium analysis of key factors involved in mesenchymal stem cell-mediated inflammatory reduction.

Increasing global birth rate, coupled with the aging population surviving into their eighth decade has lead to increased incidence diseases, hitherto designated as rare. Brain related ischemia, at birth, or later in life, during, for example stroke, is increasing in global prevalence. Reactive microglia can contribute to neuronal damage as well as compromising transplantion. One potential treatment strategy is cellular therapy, using mesenchymal stem cells (hMSCs), which possess immunomodulatory and cell repair properties. For effective clinical therapy, mechanisms of action must be understood better. Here multicentre international laboratories assessed this question together investigating application of hMSCs neural involvement, with interest in the role of reactive microglia. Modulation by hMSCs in our in vivo and in vitro study shows they decrease markers of microglial activation (lower ED1 and Iba) and astrogliosis (lower GFAP) following transplantation in an ouabain-induced brain ischemia rat model and in organotypic hippocampal cultures. The anti-inflammatory effect in vitro was demonstrated to be CD200 ligand dependent with ligand expression shown to be increased by IL-4 stimulation. hMSC transplant reduced rat microglial STAT3 gene expression and reduced activation of Y705 phosphorylated STAT3, but STAT3 in the hMSCs themselves was elevated upon grafting. Surprisingly, activity was dependent on heterodimerisation with STAT1 activated by IL-4 and Oncostatin M. Our study paves the way to preclinical stages of a clinical trial with hMSC, and suggests a non-canonical JAK-STAT signaling of unphosphorylated STAT3 in immunomodulatory effects of hMSCs.

Methylenedioxymethamphetamine ('Ecstasy')-induced immunosuppression: a cause for concern?

Methylenedioxymethamphetamine (MDMA; 'Ecstasy') is a ring-substituted amphetamine and a popular drug of abuse. In addition to ability to induce euphoria, MDMA abuse is associated with a range of acute and long-term hazardous effects. This paper is focused on once such adverse effect: its ability to negatively impact on functioning of the immune system. Research demonstrates that MDMA has immunosuppressive properties, with both innate and adaptive arms of the immune system being affected. The ability of MDMA to suppress innate immunity is indicated by impaired neutrophil phagocytosis and reduced production of dendritic cell/macrophage-derived pro-inflammatory cytokines including tumour necrosis factor-alpha, interleukin (IL)-1beta, IL-12 and IL-15. MDMA also suppresses innate IFN-gamma production, and considering the role of IFN-gamma in priming antigen-presenting cells, it is not surprising that MDMA reduces MHC class II expression on dendritic cells and macrophages, and inhibits co-stimulatory molecule expression. Paradoxically, studies demonstrate that MDMA elicits pro-inflammatory actions in the CNS by activating microglia, the resident innate immune cells in the brain. In terms of adaptive immunity, MDMA reduces circulating lymphocyte numbers, particularly CD4(+) T-cells; suppresses T-cell proliferation; and skews cytokine production in a Th(2) direction. For the most part, the immunosuppressive effects of MDMA cannot be attributed to a direct action of the drug on immune cells, but rather due to the release of endogenous immunomodulatory substances. In this regard, peripheral beta-adrenoceptors and cholinergic receptors have been shown to mediate some immunosuppressive effects of MDMA. Finally, we discuss emerging evidence indicating that MDMA-induced immunosuppression can translate into significant health risks for abusers.

Psychological stress suppresses innate IFN-gamma production via glucocorticoid receptor activation: reversal by the anxiolytic chlordiazepoxide.

Studies in humans and in animals indicate that psychological stress can modulate immune responses. Here we demonstrate that exposure to psychological stress (restraint stress) suppresses innate interferon (IFN)-gamma production in mice following an in vivo lipopolysaccharide (LPS) challenge. IFN-gamma signaling was also impaired by stress, as indicated by reduced STAT1 phosphorylation and reduced expression of the IFN-gamma-inducible genes, inducible nitric oxide synthase (iNOS) and IFN-gamma-inducible protein 10 (IP-10/CXCL10). Furthermore, restraint stress suppressed production of the IFN-gamma inducing cytokine interleukin (IL)-12 and increased production of the anti-inflammatory cytokine IL-10, which can inhibit both IL-12 and IFN-gamma production. However, using IL-10 knockout mice, we demonstrate that IL-10 does not mediate the suppressive effect of restraint stress on innate IFN-gamma production. Restraint stress increased corticosterone concentrations in serum and spleen, and consistent with a role for glucocorticoids in the immunosuppressive actions of stress, pre-treatment with the glucocorticoid receptor antagonist mifepristone completely blocked the stress-related suppression of innate IFN-gamma production. Addition of exogenous IL-12 to LPS-stimulated spleen cells reversed the suppressive effect of both restraint stress and corticosterone on IFN-gamma production. These data suggest that reduced IL-12 production is a key event in stress-induced suppression of innate IFN-gamma production. Finally, we demonstrate that pre-treatment with the anxiolytic drug chlordiazepoxide prevents the suppressive effect of stress on innate IFN-gamma production, and also attenuates the stress-induced increase in circulating corticosterone concentrations.

MDMA ("Ecstasy") suppresses the innate IFN-gamma response in vivo: a critical role for the anti-inflammatory cytokine IL-10.

Here we demonstrate that the widely abused drug methylenedioxymethamphetamine (MDMA; "Ecstasy") suppresses innate interferon (IFN)-gamma production in mice following an in vivo lipopolysaccharide (LPS) challenge. IFN-gamma signalling was also impaired by MDMA, as indicated by reduced phosphorylation of signal transducer and activator of transcription-1 (STAT1) and reduced expression of interferon-gamma inducible protein 10 (IP-10/CXCL10); a chemokine induced by IFN-gamma. MDMA also suppressed production of interleukin (IL)-12 and IL-15; two cytokines that induce IFN-gamma production. Our results demonstrate that in vitro exposure to MDMA does not mimic the suppression of innate IFN-gamma observed in vivo, indicating that observed suppression is most likely due to the release of endogenous immunomodulatory substances following drug administration. In this regard, we previously demonstrated that MDMA increases production of the anti-inflammatory cytokine IL-10 in vivo, an event that is mediated by beta-adrenoceptor activation on immune cells. Considering that increased IL-10 production precedes suppression of IFN-gamma induced by MDMA, and also considering that IL-10 can inhibit IL-12 and IFN-gamma production, we examined the possibility that IL-10 was an essential mediator of the suppressive effect of MDMA on the IFN-gamma response. By pre-treating mice with an anti-IL-10 receptor antibody we demonstrate that IL-10 is a critical mediator of MDMA-induced suppression of IFN- gamma production and signalling. Consistent with a role for beta-adrenoceptor activation in the immunosuppressive actions of MDMA, pre-treatment with the beta-adrenoceptor antagonist nadolol blocked the MDMA-induced increase in IL-10, and also inhibited the suppressive action of MDMA on the innate IFN-gamma response. The potential clinical significance of these findings for MDMA users is discussed.