Generation of Axially Chiral Fluoroallenes through a Copper-Catalyzed Enantioselective ß-Fluoride Elimination.

Herein we report the copper-catalyzed silylation of propargylic difluorides to generate axially chiral, tetrasubstituted monofluoroallenes in both good yields (27 examples >80%) and enantioselectivities (82-98% ee). Compared to previously reported synthetic routes to axially chiral allenes (ACAs) from prochiral substrates, a mechanistically distinct reaction has been developed: the enantiodiscrimination between enantiotopic fluorides to set an axial stereocenter. DFT calculations and vibrational circular dichroism (VCD) suggest that ß-fluoride elimination from an alkenyl copper intermediate likely proceeds through a syn-ß-fluoride elimination pathway rather than an anti-elimination pathway. The effects of the C1-symmetric Josiphos-derived ligand on reactivity and enantioselectivity were investigated. Not only does this report showcase that alkenyl copper species (like their alkyl counterparts) can undergo ß-fluoride elimination, but this elimination can be achieved in an enantioselective fashion.

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.

Interaction of the immune-inflammatory and the kynurenine pathways in rats resistant to antidepressant treatment in model of depression.

The kynurenine pathway (KP), a major route of tryptophan catabolism, may be associated with the pathophysiology of depressive disorders. KP is responsible for ca. 99% of brain tryptophan metabolism via its degradation to kynurenine (KYN) catalyzed by indoleamine 2,3-dioxygenase (IDO). Some cytokines, such as interferon-γ (IFN-γ) and interleukin (IL)-6 are potent inducers of IDO. KYN is further converted by kynurenine aminotransferase (KAT) to the more neuroprotective kynurenic acid or by kynurenine 3-monooxygenase (KMO) to neurotoxic 3-hydroxykynurenine. The aim of the present study was to delineate whether the administration of imipramine (IMI) to rats subjected to chronic mild stress (CMS) may reverse behavioral changes induced by CMS in association with changes in immune-inflammatory markers and KP. We confirmed that the CMS procedure modeled one of the main symptoms of depression, i.e. anhedonia, and administration of IMI for 5 weeks resulted in a significant reduction in anhedonia in a majority of animals (CMS IMI-R animals), whereas 20% of animals did not respond to IMI treatment (CMS IMI-NR animals). We established that CMS procedure increased IFN-γ and IDO mRNA and decreased KAT II mRNA expression in the rat cortex. In the cortex and hippocampus, IMI treatment and non-responsiveness to IMI (in CMS IMI-NR animals) were associated with increased IL-6 mRNA expression. In the spleen, CMS increased production of IFN-γ and IL-6 proteins, while these cytokines were decreased by IMI in CMS IMI-R animals. Chronic IMI administration to CMS rats decreased IDO and KMO mRNA and protein expression and increased KAT II/KMO mRNA and protein ratio in IMI responders (CMS IMI-R) in comparison to CMS rats. In CMS IMI-NR rats, a significant increase in IDO mRNA expression and protein level in comparison with IMI responders was observed. Our findings indicate that resistance to therapeutic action of IMI could be explained by a deficiency of the inhibitory properties of IMI on IDO, KMO and KYN synthesis in the cortex. We conclude that the antidepressant activity of IMI may, at least in part, be explained by modulatory activities on the KAT II/KMO ratio in brain areas.

Treatment with the noradrenaline re-uptake inhibitor atomoxetine alone and in combination with the α2-adrenoceptor antagonist idazoxan attenuates loss of dopamine and associated motor deficits in the LPS inflammatory rat model of Parkinson's disease.

The impact of treatment with the noradrenaline (NA) re-uptake inhibitor atomoxetine and the α2-adrenoceptor (AR) antagonist idazoxan in an animal model of Parkinson's disease (PD) was assessed. Concurrent systemic treatment with atomoxetine and idazoxan, a combination which serves to enhance the extra-synaptic availability of NA, exerts anti-inflammatory and neuroprotective effects following delivery of an inflammatory stimulus, the bacterial endotoxin, lipopolysaccharide (LPS) into the substantia nigra. Lesion-induced deficits in motor function (akinesia, forelimb-use asymmetry) and striatal dopamine (DA) loss were rescued to varying degrees depending on the treatment. Treatment with atomoxetine following LPS-induced lesion to the substantia nigra, yielded a robust anti-inflammatory effect, suppressing microglial activation and expression of the pro-inflammatory cytokine TNF-α whilst increasing the expression of neurotrophic factors. Furthermore atomoxetine treatment prevented loss of tyrosine hydroxylase (TH) positive nigral dopaminergic neurons and resulted in functional improvements in motor behaviours. Atomoxetine alone was sufficient to achieve most of the observed effects. In combination with idazoxan, an additional improvement in the impairment of contralateral limb use 7 days post lesion and a reduction in amphetamine-mediated rotational asymmetry 14 days post-lesion was observed, compared to atomoxetine or idazoxan treatments alone. The results indicate that increases in central NA tone has the propensity to regulate the neuroinflammatory phenotype in vivo and may act as an endogenous neuroprotective mechanism where inflammation contributes to the progression of DA loss. In accordance with this, the clinical use of agents such as NA re-uptake inhibitors and α2-AR antagonists may prove useful in enhancing the endogenous neuroimmunomodulatory potential of NA in conditions associated with brain inflammation.

Gold-Catalyzed Hydrofluorination of Electron-Deficient Alkynes: Stereoselective Synthesis of ß-Fluoro Michael Acceptors.

The gold(I)-catalyzed, stereoselective hydrofluorination of electron-deficient alkynes with triethylamine trihydrogen fluoride (Et3N·3HF) is described. Fluorinated α,ß-unsaturated aldehydes, amides, esters, ketones, and nitriles were isolated in moderate to good yields as single diastereomers. In all but four cases, the (Z)-vinyl fluorides were initially formed in ≥97% diastereoselectivity. This work constitutes the first catalytic example of the diastereoselective preparation of a variety of ß-alkyl, ß-fluoro Michael acceptors from alkynes. Additionally, the described work expands access to ß-aryl, ß-fluoro Michael acceptors to the synthesis of ß-fluoro-α,ß-unsaturated amides and nitriles. The monofluoroalkenes formed through this strategy were readily transformed into other fluorine-containing compounds, and the developed method was applied to the synthesis of a fluorinated analogue of Exoderil, a topical antimycotic.

Inhibition of the kynurenine pathway protects against reactive microglial-associated reductions in the complexity of primary cortical neurons.

Brain glia possess the rate limiting enzyme indoleamine 2, 3-dioxygenase (IDO) which catalyses the conversion of tryptophan to kynurenine. Microglia also express kynurenine monooxygenase (KMO) and kynureninase (KYNU) which lead to the production of the free radical producing metabolites, 3-hydroxykynurenine and 3-hydroxyanthranillic acid respectively and subsequently production of the NMDA receptor agonist quinolinic acid. The aim of this study was to examine the effect of IFNγ-stimulated kynurenine pathway (KP) induction in microglia on neurite outgrowth and complexity, and to determine whether alterations could be abrogated using pharmacological inhibitors of the KP. BV-2 microglia were treated with IFNγ (5ng/ml) for 24h and conditioned media (CM) was placed on primary cortical neurons 3 days in vitro (DIV) for 48h. Neurons were fixed and neurite outgrowth and complexity was assessed using fluorescent immunocytochemistry followed by Sholl analysis. Results show increased mRNA expression of IDO, KMO and KYNU, and increased concentrations of tryptophan, kynurenine, and 3-hydroxykynurenine in the CM of IFNγ-stimulated BV-2 microglia. The IFNγ-stimulated BV-2 microglial CM reduced neurite outgrowth and complexity with reductions in various parameters of neurite outgrowth prevented when BV-2 microglia were pre-treated with either the IDO inhibitor, 1-methyltryptophan (1-MT) (L) (0.5mM; 30min), the KMO inhibitor, Ro 61-8048 (1µM; 30min), the synthetic glucocorticoid, dexamethasone (1µM; 2h) -which suppresses IFNγ-induced IDO - and the N-methyl-D-aspartate (NMDA) receptor antagonist, MK801 (0.1µM; 30min). Overall this study indicates that inhibition of the KP in microglia may be targeted to protect against reactive microglial-associated neuronal atrophy.

Association between psychological measures with inflammatory anddisease-related markers of inflammatory bowel disease.

OBJECTIVE: This study aimed at investigating the associations between inflammatory mediators, symptoms and psychological disturbances in inflammatory bowel disease (IBD) patients. METHODS: IBD patients and patient controls were examined during a single visit to a gastroenterology clinic. Disease activity was assessed using the Mayo index for ulcerative colitis (UC), inflammatory bowel disease questionnaire (IBDQ), Crohn's disease activity index (CDAI) and Crohn's disease endoscopic index of severity (CDEIS). Gene expression of inflammatory mediators were measured in intestinal biopsies and whole blood samples along with circulating concentrations of interleukin (IL)-6, interferon (IFN)γ, C-reactive protein (CRP), kynurenine and tryptophan. Validated depression, anxiety and quality of life scores were used to assess psychological well-being. RESULTS: Patients who were symptomatic had the highest depression and anxiety scores, together with increased intestinal expression of IL-1ß, IL-6 and matrix metalloproteinase-9, increased circulating IL-6 and CRP, and an increased circulating kynurenine:tryptophan ratio. Increased Hamilton depression (HAM-D) scores in IBD patients were observed independent of the psychological impact of acute symptoms. CONCLUSIONS: Active IBD is associated with symptoms of depression and anxiety and with a raised circulating inflammatory mediator profile. Patients with active IBD exhibiting psychological symptoms should undergo psychological evaluation to ensure the psychological aspects of the condition are considered and addressed.

Homologation of α-aryl amino acids through quinone-catalyzed decarboxylation/Mukaiyama-Mannich addition.

A new method for amino acid homologation by way of formal C-C bond functionalization is reported. This method utilizes a 2-step/1-pot protocol to convert α-amino acids to their corresponding N-protected ß-amino esters through quinone-catalyzed oxidative decarboxylation/in situ Mukaiyama-Mannich addition. The scope and limitations of this chemistry are presented. This methodology provides an alternative to the classical Arndt-Eistert homologation for accessing ß-amino acid derivatives. The resulting N-protected amine products can be easily deprotected to afford the corresponding free amines.

Amitriptyline protects against TNF-α-induced atrophy and reduction in synaptic markers via a Trk-dependent mechanism.

Neuritic degeneration and synaptic loss are features of both neuroinflammation and neurodegenerative disease. The tricyclic antidepressant amitriptyline has neurotrophic and anti-inflammatory properties and acts as a novel agonist of the neurotrophin Trk receptors. Primary cortical neurons were treated with amitriptyline, nortriptyline and NGF and tested for neuronal complexity by Sholl analysis, protein expression by Western immunoblotting, and synapse number by colocalization of pre and postsynaptic makers. Amitriptyline (500 nmol/L) and its active metabolite nortriptyline (50 nmol/L) are found to induce neurite outgrowth in rat primary cortical neurons. Amitriptyline-induced neurite outgrowth is blocked by inhibition of Trk signaling using Trk antagonist K252a (200 nmol/L) but not by the neurotrophin inhibitor Y1036 (40 µmol/L), indicating that amitriptyline binds directly to the Trk receptor to initiate neurite outgrowth. MEK inhibitor PD98059 (10 µmol/L) also blocks amitriptyline-induced neurite outgrowth, implicating activation of the MAPK signaling pathway downstream of Trk receptor activation. Furthermore, pretreatment of primary cortical neurons with amitriptyline and nortriptyline prevents the effects of the proinflammatory cytokine TNF-α (10 ng/mL) on neurite outgrowth and colocalization of synaptic proteins. These findings suggest that amitriptyline and nortriptyline can exert neurotrophic effects in primary cortical neurons via activation of a Trk/MAPK signaling pathway. These compounds therefore have significant potential to be used in the treatment of neurodegenerative conditions where atrophy and loss of synaptic connections contribute to progression of disease.

Clenbuterol activates the central IL-1 system via the ß2-adrenoceptor without provoking inflammatory response related behaviours in rats.

The long-acting, highly lipophilic, ß2-adrenoceptor agonist clenbuterol may represent a suitable therapeutic agent for the treatment of neuroinflammation as it drives an anti-inflammatory response within the CNS. However, clenbuterol is also known to increase the expression of IL-1ß in the brain, a potent neuromodulator that plays a role in provoking sickness related symptoms including anxiety and depression-related behaviours. Here we demonstrate that, compared to the immunological stimulus lipopolysaccharide (LPS, 250µg/kg), clenbuterol (0.5mg/kg) selectively up-regulates expression of the central IL-1 system resulting in a mild stress-like response which is accompanied by a reduction in locomotor activity and food consumption in rats. We provide further evidence that clenbuterol-induced activation of the central IL-1 system occurs in a controlled and selective manner in tandem with its negative regulators IL-1ra and IL-1RII. Furthermore, we demonstrate that peripheral ß2-adrenoceptors mediate the suppression of locomotor activity and food consumption induced by clenbuterol and that these effects are not linked to the central induction of IL-1ß. Moreover, despite increasing central IL-1ß expression, chronic administration of clenbuterol (0.03mg/kg; twice daily for 21days) fails to induce anxiety or depressive-like behaviour in rats in contrast to reports of the ability of exogenously administered IL-1 to induce these symptoms in rodents. Overall, our findings suggest that clenbuterol or other selective ß2-adrenoceptor agonists could have the potential to combat neuroinflammatory or neurodegenerative disorders without inducing unwanted symptoms of depression and anxiety.

Stress-Related Immune Markers in Depression: Implications for Treatment.

Major depression is a serious psychiatric disorder; however, the precise biological basis of depression still remains elusive. A large body of evidence implicates a dysregulated endocrine and inflammatory response system in the pathogenesis of depression. Despite this, given the heterogeneity of depression, not all depressed patients exhibit dysregulation of the inflammatory and endocrine systems. Evidence suggests that inflammation is associated with depression in certain subgroups of patients and that those who have experienced stressful life events such as childhood trauma or bereavement may be at greater risk of developing depression. Consequently, prolonged exposure to stress is thought to be a key trigger for the onset of a depressive episode. This review assesses the relationship between stress and the immune system, with a particular interest in the mechanisms by which stress impacts immune function, and how altered immune functioning, in turn, may lead to a feed forward cascade of multiple systems dysregulation and the subsequent manifestation of depressive symptomology. The identification of stress-related immune markers and potential avenues for advances in therapeutic intervention is vital. Changes in specific biological markers may be used to characterize or differentiate depressive subtypes or specific symptoms and may predict treatment response, in turn facilitating a more effective, targeted, and fast-acting approach to treatment.

Crystal structures of 4-chloro-pyridine-2-carbo-nitrile and 6-chloro-pyridine-2-carbo-nitrile exhibit different inter-molecular π-stacking, C-H⋯Nnitrile and C-H⋯Npyridine inter-actions.

The two title compounds are isomers of C6H3ClN2 containing a pyridine ring, a nitrile group, and a chloro substituent. The mol-ecules of each compound pack together in the solid state with offset face-to-face π-stacking, and inter-molecular C-H⋯Nnitrile and C-H⋯Npyridine inter-actions. 4-Chloro-pyridine-2-carbo-nitrile, (I), exhibits pairwise centrosymmetric head-to-head C-H⋯Nnitrile and C-H⋯Npyridine inter-actions, forming one-dimensional chains, which are π-stacked in an offset face-to-face fashion. The inter-molecular packing of the isomeric 6-chloro-pyridine-2-carbo-nitrile, (II), which differs only in the position of the chloro substituent on the pyridine ring, exhibits head-to-tail C-H⋯Nnitrile and C-H⋯Npyridine inter-actions, forming two-dimensional sheets which are π-stacked in an offset face-to-face fashion. In contrast to (I), the offset face-to-face π-stacking in (II) is formed between mol-ecules with alternating orientations of the chloro and nitrile substituents.

Characterisation of the antidepressant properties of nitric oxide synthase inhibitors in the olfactory bulbectomised rat model of depression.

Nitric oxide synthase (NOS) inhibitors possess antidepressant-like properties in preclinical tests and in the current investigation the brain penetrant NOS inhibitor N(ω)-nitro-L-arginine (l-NA) and the preferential inhibitor of neuronal NOS (nNOS) 1-(2-trifluoromethylphenyl) imidazole (TRIM) were assessed in the olfactory bulbectomised (OB) rat, a well-established animal model of depression. Magnetic resonance imaging (MRI) was employed to assess regional brain volumes, blood perfusion and T1 and T2 relaxometry times both with and without drug treatment. l-NA (10 mg/kg, once daily p.o. for 10 days) attenuated OB-related hyperactivity in the "open field" test in a comparable fashion to the tricyclic antidepressant imipramine (20 mg/kg, once daily p.o. for 14 days) indicative of an antidepressant-like response in the model. Treatment with TRIM (50 mg/kg, once daily s.c.) attenuated OB-related hyperactivity following 7 days of treatment when compared to vehicle treated controls. OB is associated with enlarged ventricular volume, increased periventicular perfusion and a decrease in T2 relaxation times in cortical and hippocampal regions, with enhanced perfusion and reduced T2 times attenuated by L-NA treatment. L-NA treatment was also associated with an increase in T1 relaxation times in limbic and cortical regions and found to reduce resting state hippocampal blood perfusion in OB animals. Behavioural observations are consistent with an antidepressant action of NOS inhibitors where associated changes in perfusion and T2 relaxation times may be related to the antidepressant action of L-NA in the model.

Age-associated dysregulation of microglial activation is coupled with enhanced blood-brain barrier permeability and pathology in APP/PS1 mice.

Aging adversely affects inflammatory processes in the brain, which has important implications in the context of disease progression. It has been proposed that microglia become dysfunctional with age and may lose their neuroprotective properties leading to chronic neurodegeneration. Here, we sought to characterize inflammatory changes in a mouse model of Alzheimer's disease and to delineate differences between normal aging and those associated with disease pathology. A proinflammatory profile, characterized by the upregulation of markers of classical activation, was evident in APPswe/PS1dE9 mice, associated with increased interferon-γ (IFNγ) concentration and dysregulation of mechanisms designed to limit the proinflammatory response. The data indicate that microglia are not less active with age but alter their phenotype; indeed, changes observed in the deactivation state appear to relate to aging rather than disease pathology. We hypothesize that disruption of the blood-brain barrier, in tandem with an enhanced chemokine profile, permits the infiltration of immune cells serving to reinforce classical activation of microglia through their enhanced responsiveness to IFNγ.

Inhibition of stress-induced hepatic tryptophan 2,3-dioxygenase exhibits antidepressant activity in an animal model of depressive behaviour.

The role of hepatic tryptophan 2,3 dioxygenase (TDO) was assessed in the provocation of stress-induced depression-related behaviour in the rat. TDO drives tryptophan metabolism via the kynurenine pathway (KP) and leads to the production of neuroactive metabolites including kynurenine. A single 2 h period of restraint stress in adult male Sprague-Dawley rats provoked an increase in circulating concentrations of the glucocorticoid corticosterone and induction of hepatic TDO expression and activity. Repeated exposure to stress (10 d of 2 h restraint each day) provoked an increase in immobility in the forced swimming test (FST) indicative of depression-related behaviour. Immobility was accompanied by an increase in the circulating corticosterone concentrations, expression and activity of hepatic TDO and increase in the expression of TDO in the cerebral cortex. Increased TDO activity was associated with raised circulating kynurenine concentrations and a reduction in circulating tryptophan concentrations indicative of KP activation. Co-treatment with the TDO inhibitor allopurinol (20 mg/kg, i.p.), attenuated the chronic stress-related increase in immobility in the FST and the accompanying increase in circulating kynurenine concentrations. These findings indicate that stress-induced corticosterone and consequent activation of hepatic TDO, tryptophan metabolism and production of kynurenine provoke a depression-related behavioural phenotype. Inhibition of stress-related hepatic TDO activity promotes antidepressant activity. TDO may therefore represent a promising target for the treatment of depression associated with stress-related disorders in which there is evidence for KP activation.

Noradrenaline acting on astrocytic ß2-adrenoceptors induces neurite outgrowth in primary cortical neurons.

The neurotransmitter noradrenaline (NA) has anti-inflammatory properties and promotes expression of neurotrophic factors in the central nervous system (CNS) via activation of glial adrenoceptors. Here we examined the ability of conditioned media (CM) from NA-treated glial cells to impact upon neuronal complexity. Primary rat cortical neurons were treated either directly with NA (1-10 µM), or treated with CM from NA-stimulated primary mixed glial cells. Neuronal complexity was assessed using Sholl analysis. Exposure of neurons to CM from NA-stimulated glial cells increased all indices of neuronal complexity, whereas direct exposure of neurons to NA did not. CM from NA-stimulated astrocytes, but not microglia, also increased neuronal complexity indicating a key role for astrocytes. The ß-adrenergic subtype was implicated in this response as the increase was blocked by the ß-adrenoceptor antagonist propanolol, but not by the α-adrenoceptor antagonist phentolamine. CM from glial cells treated with the ß2-adrenoceptor agonists salmeterol and clenbuterol, but not the ß1-adrenoceptor agonist xamoterol, mimicked the ability of NA to increase neuronal complexity. NA induced expression of a range of growth factors (BDNF, NGF-ß, GDNF, FGF-2 and IL-6) in glial cells. In addition to this, the phosphatidylinositol 3-kinase (PI3K), mitogen activated protein kinase (MAPK) and JAK-STAT signalling pathways are implicated in NA CM-induced neuritic growth as inhibition of these pathways attenuated NA CM-induced neuritic growth. In conclusion, this study indicates a novel role for NA acting at glial ß2-adrenoceptors to induce neuritic growth through the expression of soluble factors that elicit a neurotrophic action and increase neuronal complexity.

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.

Stimulation of central ß2-adrenoceptors suppresses NFκB activity in rat brain: a role for IκB.

In this study we examined the impact of systemic treatment with the long-acting brain penetrant ß2-adrenoceptor agonist clenbuterol on NFκB activity and IκB expression in rat brain. Clenbuterol decreased NFκB activity (p65 DNA binding) in nuclear extracts prepared from rat cortex and hippocampus for up to 8h following a single treatment. This was accompanied by increased expression of IκBα mRNA and protein. The temporal increase in IκB protein expression paralleled the suppression of NFκB activity, suggesting that IκBα mediates the suppression NFκB activity observed. These actions of clenbuterol were prevented by pre-treatment with the non-selective ß-adrenoceptor antagonist propranolol, the ß2-adrenoceptor antagonist ICI-118,551, but not the ß1-adrenoceptor antagonist metoprolol, suggesting that the effects of clenbuterol on IκBα expression and NFκB activity are mediated specifically by the ß2-adrenoceptor. In addition, the actions of clenbuterol were mimicked by systemic administration of another highly selective long-acting ß2-adrenoceptor agonist formoterol. As neurodegenerative diseases are associated with inflammation we determined if clenbuterol could suppress NFκB activation that occurs in response to an inflammatory stimulus. In this regard we demonstrate that clenbuterol inhibited IκB phosphorylation and IκB degradation and inhibited NFκB activity in hippocampus and cortex of rats following a central injection of the inflammagen bacterial lipopolysaccharide (LPS). In tandem, clenbuterol blocked expression of the NFκB-inducible genes TNF-α and ICAM-1 following LPS administration. Our finding that clenbuterol and formoterol inhibit NFκB activity in the CNS further supports the idea that ß2-adrenoceptors may be an attractive target for treating neuroinflammation and combating inflammation-related neurodegeneration.

Glial Activation in AßPP/PS1 Mice is Associated with Infiltration of IFNγ-Producing Cells.

Whereas the classical histological hallmarks of Alzheimer's disease (AD) are deposition of amyloid-containing plaques and development of neurofibrillary tangles, there is also clear evidence of inflammatory changes accompanied by the presence of activated microglia and astrocytosis. However, at this time, it remains uncertain whether inflammatory changes contribute to pathogenesis of the disease or if they are secondary to deposition of amyloid-ß or other pathological changes. A greater understanding of the sequence of events would clearly improve development of strategies to delay progression of the disease. There is a realistic expectation that advances in imaging technology may provide the key to uncovering this sequence. In this study, we employed non-invasive imaging techniques to examine changes in tissue state in hippocampus and cortex of transgenic mice which overexpress amyloid-ß protein precursor and presenilin 1 and show that the observed increase in T1 relaxation time was associated with astrogliosis while the decrease in T2 relaxation time was associated with microglial activation. We explored the possibility that interferon-γ might trigger glial activation and demonstrate a genotype-related infiltration of macrophages and natural killer cells, which release interferon-γ. The evidence suggests that IFNγ triggers glial activation and expression of proinflammatory cytokines, and these changes, in turn, contribute to the decrease in long-term potentiation.

Identifying early inflammatory changes in monocyte-derived macrophages from a population with IQ-discrepant episodic memory.

BACKGROUND: Cells of the innate immune system including monocytes and macrophages are the first line of defence against infections and are critical regulators of the inflammatory response. These cells express toll-like receptors (TLRs), innate immune receptors which govern tailored inflammatory gene expression patterns. Monocytes, which produce pro-inflammatory mediators, are readily recruited to the central nervous system (CNS) in neurodegenerative diseases. METHODS: This study explored the expression of receptors (CD11b, TLR2 and TLR4) on circulating monocyte-derived macrophages (MDMs) and peripheral blood mononuclear cells (PBMCs) isolated from healthy elderly adults who we classified as either IQ memory-consistent (high-performing, HP) or IQ memory-discrepant (low-performing, LP). RESULTS: The expression of CD11b, TLR4 and TLR2 was increased in MDMs from the LP group when compared to HP cohort. MDMs from both groups responded robustly to treatment with the TLR4 activator, lipopolysaccharide (LPS), in terms of cytokine production. Significantly, MDMs from the LP group displayed hypersensitivity to LPS exposure. INTERPRETATION: Overall these findings define differential receptor expression and cytokine profiles that occur in MDMs derived from a cohort of IQ memory-discrepant individuals. These changes are indicative of inflammation and may be involved in the prodromal processes leading to the development of neurodegenerative disease.