Publications (15)64.75 Total impact
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Article: Octopamine, unlike other trace amines, inhibits responses of astroglia-enriched cultures to lipopolysaccharide via a β-adrenoreceptor-mediated mechanism.
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ABSTRACT: Trace amines (TAs), i.e. β-phenylethylamine, tyramine and octopamine, are generally regarded as sympathomimetic compounds with structural and functional analogy with catecholamines. Previous reports have shown particularly high levels of circulating TAs in migraine and cluster headache patients. However, no clues are yet available as to the pathophysiological significance of these alterations. The effect of different TAs on the release of nitric oxide was investigated in rat astroglial cells stimulated with lipopolysaccharide (LPS). Octopamine substantially inhibited the release of NO evoked by LPS. Tyramine and β-PEA were ineffective. The inhibitory effect of octopamine was fully reverted by two selective antagonists of β-adrenergic receptors, while α-adrenergic blockade was ineffective. These data, consistent with a role of octopamine as a modulator of NO release, uncover an interaction between octopamine and β-adrenergic receptors in astroglial cells. These results may have an impact in understanding the mechanisms underlying migraine pathophysiology.Neuroscience Letters 04/2012; 517(1):36-40. · 2.11 Impact Factor -
Article: A new class of antitumor trans-amine-amidine-Pt(II) cationic complexes: influence of chemical structure and solvent on in vitro and in vivo tumor cell proliferation.
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ABSTRACT: The reactions of cyclopropylamine, cyclopentylamine, and cyclohexylamine with trans-[PtCl2(NCMe)2] afforded the bis-cationic complexes trans-[Pt(amine)2(Z-amidine)2]2+[Cl-]2, 1-3. The solution behavior and biological activity have been studied in different solvents (DMSO, water, polyethylene glycol (PEG 400), and polyethylene glycol dimethyl ether (PEG-DME 500)). The biological activity was strongly influenced by the cycloaliphatic amine ring size, with trans-[Pt(NH2CH(CH2)4CH2)2{N(H) horizontal lineC(CH3)N(H)CH(CH2)4CH2}2]2+[Cl-]2 (3) being the most active compound. Complex 3 overcame both cisplatin and MDR resistance, inducing cancer cell death through p53-mediated apoptosis. Alkaline single-cell gel electrophoresis experiments indicated direct DNA damage, reasonably attributable to DNA adducts of trans-[PtCl(amine)(Z-amidine)2][Cl] species, which can evolve to produce disruptive and nonrepairable lesions on DNA, thus leading to the drug-induced programmed cancer cell death. Preliminary in vivo antitumor studies on C57BL mice bearing Lewis lung carcinoma highlighted that complex 3 promoted a significant and dose-dependent tumor growth inhibition without adverse side effects.Journal of Medicinal Chemistry 08/2010; 53(16):6210-27. · 4.80 Impact Factor -
Article: CHF5074, a novel gamma-secretase modulator, restores hippocampal neurogenesis potential and reverses contextual memory deficit in a transgenic mouse model of Alzheimer's disease.
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ABSTRACT: The effects of compounds interfering with gamma-secretase, the enzymatic complex responsible of the formation of the amyloid-beta (Abeta) peptide from amyloid-beta protein precursor (AbetaPP), on plaque deposition in transgenic mouse models of Alzheimer's disease are known but scanty data are available on the effects of these drugs on brain plasticity. We evaluated the effects of long-term treatment with CHF5074, a new gamma-secretase modulator, on hippocampal neurogenesis, cortical synaptophysin levels, and contextual memory in transgenic mice carrying the double Swedish mutation of AbetaPP (Tg2576). Six-month old Tg2576 mice were treated with CHF5074 (375 ppm in the diet) up to 15 months of age. Age-matched control transgenic and wild-type mice received standard diet. Compared to wild-type animals, transgenic controls showed a significant decrease in the number of doublecortin-positive neuroblasts in dentate gyrus, synaptophysin intensity in the cortex, freezing to context in the contextual fear conditioning test. Compared to transgenic controls, CHF5074 treatment of Tg2576 mice resulted in a significant attenuation of the neurogenesis impairment in hippocampus (p=0.036), normalization of synaptophysin levels in cortex (p< 0.001), attenuation of plaque burden in the cortex (p=0.033), increases astroglial reaction around plaques (p=0.001), and attenuation of activated microglia (p=0.040). These effects were associated to a complete reversal of contextual memory deficit (p=0.006). Contextual memory significantly correlated with synaptophysin immunoreactivity in the cortex (r=0.548, p=0.0038).Journal of Alzheimer's disease: JAD 02/2010; 20(1):159-73. · 3.74 Impact Factor -
Article: In vitro antitumor activity of the water soluble copper(I) complexes bearing the tris(hydroxymethyl)phosphine ligand.
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ABSTRACT: Monocationic hydrophilic complexes [Cu(thp)4](+) 3 and [Cu(bhpe)2](+) 4 were synthesized by ligand exchange reactions starting from the labile [Cu(CH3CN)4][PF6] precursor in the presence of an excess of the relevant hydrophilic phosphine. Complexes 3 and 4 were tested against a panel of several human tumor cell lines. Complex 3 has been shown to be about 1 order of magnitude more cytotoxic than cisplatin. Chemosensitivity tests performed on cisplatin and multidrug resistance phenotypes suggested that complex 3 acts via a different mechanism of action than the reference drug. Different short-term proliferation assays suggested that lysosomal damage is an early cellular event associated with complex 3 cytotoxicity, probably mediated by an increased production of reactive oxygen species. Cytological stains and flow cytometric analyses indicated that the phosphine copper(I) complex is able to inhibit the growth of tumor cells via G2/M cell cycle arrest and paraptosis accompanied with the loss of mitochondrial transmembrane potential.Journal of Medicinal Chemistry 03/2008; 51(4):798-808. · 5.25 Impact Factor -
Article: 1-(3',4'-Dichloro-2-fluoro[1,1'-biphenyl]-4-yl)-cyclopropanecarboxylic acid (CHF5074), a novel gamma-secretase modulator, reduces brain beta-amyloid pathology in a transgenic mouse model of Alzheimer's disease without causing peripheral toxicity.
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ABSTRACT: Some nonsteroidal anti-inflammatory drugs has been shown to allosterically modulate the activity of gamma-secretase, the enzymatic complex responsible for the formation of beta-amyloid (Abeta). 1-(3',4'-Dichloro-2-fluoro[1,1'-biphenyl]-4-yl)-cyclopropanecarboxylic acid (CHF5074) is a new gamma-secretase modulator, devoid of anticyclooxygenase (COX) and Notch-interfering activities in vitro. We evaluated the effects of chronic CHF5074 treatment on brain Abeta pathology in Tg2576 transgenic mice. Twenty-eight animals of 9.5 to 10.5 months of age received CHF5074-medicated diet (375 ppm) or standard diet for 17 weeks. Compared with controls, CHF5074 treatment significantly reduced the area occupied by plaques and the number of plaques in cortex (-52.2 +/- 5.6%, p = 0.0003 and -48.9 +/- 6.6%, p = 0.0004, respectively) and hippocampus (-76.7 +/- 6.4%, p = 0.004 and -66.2 +/- 10.3%, p = 0.037, respectively). Biochemical analysis confirmed the histopathological measures, with CHF5074-treated animals showing reduced total brain Abeta40 (-49.2 +/- 9.2%, p = 0.017) and Abeta42 (-43.5 +/- 9.7%, p = 0.027) levels. In a human neuroglioma cell line expressing Swedish mutated form of amyloid precursor protein (H4swe), CHF5074 reduced Abeta42 and Abeta40 secretion, with an IC50 of 3.6 and 18.4 microM, respectively, values consistent with those measured in the brain of the CHF5074-treated Tg2576 mice (6.4 +/- 0.4 microM). At 5 microM, no effects were observed on Notch intracellular cleavage in human embryonic kidney 293swe cells. CHF5074 was well tolerated by Tg2576 mice. No abnormal findings were observed upon histopathological examination of the gastrointestinal tract, indicating the absence of COX-related toxicity. Semiquantitative histochemical evaluation of goblet cells in the ileum of vehicle- and CHF5074-treated animals yielded similar results, suggesting no effects on Notch pathway. CHF5074 is therefore a promising therapeutic agent for Alzheimer's disease.Journal of Pharmacology and Experimental Therapeutics 01/2008; 323(3):822-30. · 3.83 Impact Factor -
Article: Cannabidiol, unlike synthetic cannabinoids, triggers activation of RBL-2H3 mast cells.
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ABSTRACT: Cannabidiol (CBD), a prominent psychoinactive component of cannabis with negligible affinity for known cannabinoid receptors, exerts numerous pharmacological actions, including anti-inflammatory and immunosuppressive effects, the underlying mechanisms of which remain unclear. In the current study, we questioned whether CBD modulates activation of mast cells, key players in inflammation. By using the rat basophilic leukemia mast cell line (RBL-2H3), we demonstrate that CBD (3-10 muM) augments beta-hexosaminidase release, a marker of cell activation, from antigen-stimulated and unstimulated cells via a mechanism, which is not mediated by G(i)/G(o) protein-coupled receptors but rather is associated with a robust rise in intracellular calcium ([Ca(2+)](i)) levels sensitive to clotrimazole and nitrendipine (10-30 muM). This action, although mimicked by Delta(9)-tetrahydrocannabinol (THC), is opposite to that inhibitory, exerted by the synthetic cannabinoids WIN 55,212-2 and CP 55,940. Moreover, the vanilloid capsaicin, a full agonist of transient receptor potential channel VR1, did not affect [Ca(2+)](i)levels in the RBL-2H3 cells, thus excluding the involvement of this receptor in the CBD-mediated effects. Together, these results support existence of yet-to-be identified sites of interaction, i.e., receptors and/or ion channels associated with Ca(2+) influx of natural cannabinoids such as CBD and THC, the identification of which has the potential to provide for novel strategies and agents of therapeutic interest.Journal of Leukocyte Biology 07/2007; 81(6):1512-22. · 4.99 Impact Factor -
Article: Fifty Hertz electromagnetic field exposure stimulates secretion of beta-amyloid peptide in cultured human neuroglioma.
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ABSTRACT: Recent epidemiological studies raise the possibility that individuals with occupational exposure to low frequency (50-60 Hz) electromagnetic fields (LF-EMF), are at increased risk of Alzheimer's disease (AD). However, the mechanisms through which LF-EMF may affect AD pathology are unknown. We here tested the hypothesis that the exposure to LF-EMF may affect amyloidogenic processes. We examined the effect of exposure to 3.1 mT 50 Hz LF-EMF on Abeta secretion in H4 neuroglioma cells stably overexpressing human mutant amyloid precursor protein. We found that overnight exposure to LF-EMF induces a significant increase of amyloid-beta peptide (Abeta) secretion, including the isoform Abeta 1-42, without affecting cell survival. These findings show for the first time that exposure to LF-EMF stimulates Abeta secretion in vitro, thus alluding to a potential link between LF-EMF exposure and APP processing in the brain.Neuroscience Letters 06/2007; 418(1):9-12. · 2.11 Impact Factor -
Article: In vitro and in vivo profiling of CHF5022 and CHF5074 Two beta-amyloid1-42 lowering agents.
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ABSTRACT: Long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) may delay or prevent the onset of Alzheimer's disease (AD). A subset of NSAIDs, including flurbiprofen, has been shown to selectively inhibit the production of beta-amyloid(1-42) (Abeta42), independently from their cyclooxygenase (COX) inhibiting activity. We evaluated the in vitro and in vivo profiles of CHF5022 and CHF5074, two flurbiprofen analogues. The in vitro Abeta inhibiting activity was evaluated in a human neuroglioma cell line (H4) carrying the double Swedish mutation (K595N/M596L) of the human amyloid precursor protein (APPsw). The in vitro anti-COX activity was evaluated using human recombinant enzymes isolated from transfected Sf-9 cells. The in vivo pharmacokinetic and pharmacodynamic profiles of the two compounds were evaluated in young APPsw transgenic mice (Tg2576) after oral gavage (100 or 300mgkg(-1) day(-1) for 4-5 days) and after medicated diet (375ppm for 4 weeks). R-Flurbiprofen was used as comparator. In vitro, CHF5022 and CHF5074 were found to be 3- and 7-fold more potent than R-flurbiprofen in inhibiting Abeta42 secretion (IC(50)s of 92, 40 and 268microM, respectively). Differently from R-flurbiprofen, CHF5022 and CHF5074 did not affect COX-1 (at 100microM) and COX-2 (at 300microM) activity. Similarly to R-flurbiprofen, no significant alteration in the expression profile of a subset of Notch intracellular domain-responsive genes was observed with either CHF5022 or CHF5074. In Tg2576 mice, CHF5022 was well tolerated when administered by oral gavage (100mgkg(-1) day(-1) for 5 days) or by medicated diet (56mg kg(-1) day(-1) for 4 weeks). R-Flurbiprofen was poorly tolerated in the diet (32mgkg(-1) day(-1)) with 55% of the animals dying during the first week of treatment. After 4-5 days of oral gavage, CHF5022 and CHF5074 plasma and brain levels at 3h were found to increase with the dose, leading to brain concentrations of about 10% and 5% of the corresponding plasma concentrations, respectively. In animals fed for 4 weeks with compound-supplemented diet, mean plasma (580microM) and brain (20microM) Cyrillic) concentrations of CHF5022 were 8 and 15 times higher than those of R-flurbiprofen. Plasma Abeta42 concentration was dose-dependently decreased by CHF5022 and CHF5074. Brain Abeta levels (formic acid-extractable) were not significantly affected by either compound, although Abeta42 levels tended to inversely correlate (P=0.105) with CHF5022 concentration in the brain. CHF5022 and CHF5074 thus appear to have a promising in vitro and in vivo profile. This warrants further evaluation of their long-term effects on Abeta brain pathology.Pharmacological Research 05/2007; 55(4):318-28. · 4.44 Impact Factor -
Article: Longitudinal analysis of immune cell phenotypes in early stage multiple sclerosis: distinctive patterns characterize MRI-active patients.
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ABSTRACT: To investigate whether peripheral immune abnormalities are associated with brain inflammation in multiple sclerosis, and whether differences in MRI activity are paralleled by changes in leukocyte composition, we conducted a prospective longitudinal study in patients at their clinical onset. Twenty patients presenting a first inflammatory event in the central nervous system suggestive of multiple sclerosis underwent, every 45 days for one year, immunophenotyping of 98 blood cell subsets together with brain MRI and clinical evaluation. Six patients showed intense MRI activity, six patients did not display MRI activity, while the remaining 8 patients had low (i.e. intermediate) MRI activity during the follow-up. Our results show that MRI-active and MRI-inactive patients display significant differences in ten lymphocyte subsets. Among these, there are both effector (CCR7-CD45RA-CD4+ alphabeta T cells, CCR5+ gammadelta T cells) and regulatory (DN CD28+ alphabeta T cells and CD25+CD8+ alphabeta T cells) lymphocytes pertaining to the innate and the acquired arms of the immune system. Moreover, these differences were, upon employment of a class prediction procedure based on "support vector machines" algorithm utilizing leave-one-out cross validation procedures, able to correctly assign patients to their respective MRI activity group. All 6 MRI-active and 6 MRI-inactive patients were correctly classified, and, upon application of a class prediction model in an unsupervised manner to the 8 patients with intermediate MRI activity, 6 were predicted as MRI-active and 2 as MRI-inactive patients. Also, when the mean values of the first three time points (T0, T1 and T2) were used for the prediction of all patients, the selected lymphocyte subsets correctly classified 90% of patients. Sensitivity was 91.7% and specificity was 87.5%. These results provide evidence showing that brain inflammation in multiple sclerosis is associated with distinct changes in peripheral lymphocyte subsets, and raise the possibility that the identified subsets may, after adequate validation, assist in the prediction of MRI activity in the early stages of multiple sclerosis.Brain 09/2006; 129(Pt 8):1993-2007. · 9.46 Impact Factor -
Article: Nimodipine selectively stimulates beta-amyloid 1-42 secretion by a mechanism independent of calcium influx blockage.
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ABSTRACT: Several lines of evidence indicate that perturbed cellular Ca2+ homeostasis may play a prominent role in synaptic dysfunction and neuronal death in Alzheimer's disease (AD), suggesting a potential benefit of drugs capable to stabilize Ca2+ homeostasis. We here investigated the effects of a panel of L-type Ca2+ channel antagonists on the secretion of the amyloid beta-peptide (Abeta), which abnormally accumulates in the senile plaques of the brain of AD patients. We found that, in primary and immortalized neuronal cells in culture, nimodipine robustly stimulated secretion (up to about four-fold at 30 microM) of the highly amyloidogenic 42-residue isoform of Abeta (Abeta42), while leaving largely unaffected total Abeta secretion. An analogous effect was also observed in vivo, as the administration of a single dose of nimodipine (10 mg/kg i.p.) induced a significant rise of Abeta42 levels in plasma of Tg2576 mice. The effect of nimodipine was independent of blockage of L-type Ca2+ channels and capacitative calcium entry. Accordingly, nimodipine effect was largely Ca2+-independent, as neither depletion nor rise of extracellular Ca2+ abolished it. Hence, by showing that the effect of nimodipine on Abeta42 production is distinct from its ability to block Ca2+-influx pathways, we provide evidence for a previously uncharacterized effect of this long known molecule also used in clinical practice.Neurobiology of Aging 03/2006; 27(2):218-27. · 6.19 Impact Factor -
Article: Synthesis and biological activity of flurbiprofen analogues as selective inhibitors of beta-amyloid(1)(-)(42) secretion.
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ABSTRACT: Flurbiprofen, a nonsteroidal antiinflammatory drug (NSAID), has been recently described to selectively inhibit beta-amyloid(1)(-)(42) (Abeta42) secretion, the most toxic component of the senile plaques present in the brain of Alzheimer patients. The use of this NSAID in Alzheimer's disease (AD) is hampered by a significant gastrointestinal toxicity associated with cyclooxygenase (COX) inhibition. New flurbiprofen analogues were synthesized, with the aim of increasing Abeta42 inhibitory potency while removing anti-COX activity. In vitro ADME developability parameters were taken into account in order to identify optimized compounds at an early stage of the project. Appropriate substitution patterns at the alpha position of flurbiprofen allowed for the complete removal of anti-COX activity, while modifications at the terminal phenyl ring resulted in increased inhibitory potency on Abeta42 secretion. In rats, some of the compounds appeared to be well absorbed after oral administration and to penetrate into the central nervous system. Studies in a transgenic mice model of AD showed that selected compounds significantly decreased plasma Abeta42 concentrations. These new flurbiprofen analogues represent potential drug candidates to be developed for the treatment of AD.Journal of Medicinal Chemistry 10/2005; 48(18):5705-20. · 5.25 Impact Factor -
Article: Synthesis and Biological Activity of Flurbiprofen Analogues as Selective Inhibitors of β-Amyloid1-42 Secretion
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ABSTRACT: Flurbiprofen, a nonsteroidal antiinflammatory drug (NSAID), has been recently described to selectively inhibit β-amyloid1-42 (Aβ42) secretion, the most toxic component of the senile plaques present in the brain of Alzheimer patients. The use of this NSAID in Alzheimer's disease (AD) is hampered by a significant gastrointestinal toxicity associated with cyclooxygenase (COX) inhibition. New flurbiprofen analogues were synthesized, with the aim of increasing Aβ42 inhibitory potency while removing anti-COX activity. In vitro ADME developability parameters were taken into account in order to identify optimized compounds at an early stage of the project. Appropriate substitution patterns at the alpha position of flurbiprofen allowed for the complete removal of anti-COX activity, while modifications at the terminal phenyl ring resulted in increased inhibitory potency on Aβ42 secretion. In rats, some of the compounds appeared to be well absorbed after oral administration and to penetrate into the central nervous system. Studies in a transgenic mice model of AD showed that selected compounds significantly decreased plasma Aβ42 concentrations. These new flurbiprofen analogues represent potential drug candidates to be developed for the treatment of AD.08/2005; -
Article: Dopamine inhibits responses of astroglia-enriched cultures to lipopolysaccharide via a beta-adrenoreceptor-mediated mechanism.
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ABSTRACT: We here investigated the effect of the catecholaminergic neurotransmitter dopamine (DA), on the release of two major inflammatory effectors, TNF-alpha and nitric oxide, in rat astroglia-enriched cultures stimulated with the bacterial endotoxin lipopolysaccharide (LPS). Upon LPS challenge, we observed a dramatic increase in the culture medium of the TNF-alpha protein, an effect thereafter followed by an increase of nitric oxide synthase type 2 (NOS2) mRNA and, at later times, of nitrite accumulation, an index of nitric oxide (NO) production. DA substantially inhibited the release of TNF-alpha and NO evoked by LPS, an effect not mimicked by selective agonists nor prevented by selective antagonists of the DA receptors. The inhibitory effects of DA were mimicked by noradrenalin and isoproterenol and fully reverted by propranolol, a selective antagonist of the beta-adrenergic receptors. In addition, selective antagonists of beta-adrenergic receptor type 1 (metoprolol) and type 2 (ICI-118,551) counteracted the inhibitory effects of DA on LPS-induced TNF-alpha and NO release. Accordingly, agents capable of elevating intracellular cyclic 3',5'-adenosine monophosphate (cAMP), such as forskolin and dibutyryl-cAMP, mimicked DA inhibitory effects on LPS-evoked accumulation of TNF-alpha and nitrite. These data, consistent with a role of DA as local modulator of glial inflammatory responses, uncover the existence of an interaction between DA and heterologous beta-adrenergic receptors in astroglial cells.Journal of Neuroimmunology 06/2004; 150(1-2):29-36. · 2.96 Impact Factor -
Article: Cannabinoids ablate release of TNFalpha in rat microglial cells stimulated with lypopolysaccharide.
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ABSTRACT: Upon activation, brain microglial cells release proinflammatory mediators, such as TNFalpha, which may play an important role in eliciting neuroinflammatory processes causing brain damage. As cannabinoids have been reported to exert anti-inflammatory and neuroprotective actions in the brain, we here examined the effect of both synthetic and endogenous cannabinoids on TNFalpha release elicited by bacterial endotoxin lypopolysaccharide (LPS) in cultured microglia. Exposure of primary cultures of rat cortical microglial cells to LPS significantly stimulated TNFalpha mRNA expression and release. The endogenous cannabinoids anandamide and 2-arachidonylglycerol (2-AG), as well as the synthetic cannabinoids (+)WIN 55,212-2, CP 55,940, and HU210, inhibited in a concentration-dependent manner (1-10 microM) the LPS-induced TNFalpha release. Unlike the high-affinity cannabinoid receptor agonist (+)WIN 55,212-2, the low-affinity stereoisomer (-)WIN 55,212-2 did not exert any significant inhibition on TNFalpha release. Given this stereoselectivity, the ability of (+)WIN 55,212-2 to inhibit LPS-induced TNFalpha release from microglia is most likely receptor-mediated. By RT-PCR we found that the two G(i/o) protein-coupled cannabinoid receptors (type 1 and 2) are both expressed in microglial cultures. However, selective antagonists of type 1 (SR141716A and AM251) and type 2 (SR144528) cannabinoid receptors did not affect the effect of (+)WIN 55,212-2. Consistent with this finding is the observation that the ablative effect of (+)WIN 55,212-2 on LPS-evoked release of TNFalpha was not sensitive to the G(i/o) protein inactivator pertussis toxin. In addition, the cAMP elevating agents dibutyryl cAMP and forskolin both abolished LPS-induced TNFalpha release, thus rendering unlikely the possibility that (+)WIN 55,212-2 could ablate TNFalpha release through the inhibition of adenylate cyclase via the G(i)-coupled cannabinoid receptors type 1 and 2. In summary, our data indicate that both synthetic and endogenous cannabinoids inhibit LPS-induced release of TNFalpha from microglial cells. By showing that such effect does not appear to be mediated by either CB receptor type 1 or 2, we provide evidence suggestive of the existence of yet unidentified cannabinoid receptor(s) in brain microglia.Glia 02/2003; 41(2):161-8. · 4.82 Impact Factor -
Article: Cannabinoids ablate release of TNFα in rat microglial cells stimulated with lypopolysaccharide
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ABSTRACT: Upon activation, brain microglial cells release proinflammatory mediators, such as TNFα, which may play an important role in eliciting neuroinflammatory processes causing brain damage. As cannabinoids have been reported to exert anti-inflammatory and neuroprotective actions in the brain, we here examined the effect of both synthetic and endogenous cannabinoids on TNFα release elicited by bacterial endotoxin lypopolysaccharide (LPS) in cultured microglia. Exposure of primary cultures of rat cortical microglial cells to LPS significantly stimulated TNFα mRNA expression and release. The endogenous cannabinoids anandamide and 2-arachidonylglycerol (2-AG), as well as the synthetic cannabinoids (+)WIN 55,212-2, CP 55,940, and HU210, inhibited in a concentration-dependent manner (1–10 μM) the LPS-induced TNFα release. Unlike the high-affinity cannabinoid receptor agonist (+)WIN 55,212-2, the low-affinity stereoisomer (−)WIN 55,212-2 did not exert any significant inhibition on TNFα release. Given this stereoselectivity, the ability of (+)WIN 55,212-2 to inhibit LPS-induced TNFα release from microglia is most likely receptor-mediated. By RT-PCR we found that the two Gi/o protein-coupled cannabinoid receptors (type 1 and 2) are both expressed in microglial cultures. However, selective antagonists of type 1 (SR141716A and AM251) and type 2 (SR144528) cannabinoid receptors did not affect the effect of (+)WIN 55,212-2. Consistent with this finding is the observation that the ablative effect of (+)WIN 55,212-2 on LPS-evoked release of TNFα was not sensitive to the Gi/o protein inactivator pertussis toxin. In addition, the cAMP elevating agents dibutyryl cAMP and forskolin both abolished LPS-induced TNFα release, thus rendering unlikely the possibility that (+)WIN 55,212-2 could ablate TNFα release through the inhibition of adenylate cyclase via the Gi-coupled cannabinoid receptors type 1 and 2. In summary, our data indicate that both synthetic and endogenous cannabinoids inhibit LPS-induced release of TNFα from microglial cells. By showing that such effect does not appear to be mediated by either CB receptor type 1 or 2, we provide evidence suggestive of the existence of yet unidentified cannabinoid receptor(s) in brain microglia. GLIA 41:161–168, 2003. © 2003 Wiley-Liss, Inc.Glia 01/2003; 41(2):161 - 168. · 4.82 Impact Factor
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2007–2008
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Chiesi Farmaceutici S.p.A
Manchester, ENG, Italy
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