Search

Background: The endogenous cannabinoid system modulates inflammatory signaling in a variety of pathological states, including traumatic brain injury (TBI). The selective expression of diacylglycerol lipase-β (DAGL-β), the 2-arachidonylglycerol biosynthetic enzyme, on resident immune cells of the brain (microglia) and the role of this pathway in neuroinflammation, suggest that this enzyme may contribute to TBI-induced neuroinflammation. Accordingly, we tested whether DAGL-β(−/−) mice would show a protective phenotype from the deleterious consequences of TBI on cognitive and neurological motor functions. Materials and Methods: DAGL-β(−/−) and -β(+/+) mice were subjected to the lateral fluid percussion model of TBI and assessed for learning and memory in the Morris water maze (MWM) Fixed Platform (reference memory) and Reversal (cognitive flexibility) tasks, as well as in a cued MWM task to infer potential sensorimotor/motivational deficits. In addition, subjects were assessed for motor behavior (Rotarod and the Neurological Severity Score assays) and in the light/dark box and the elevated plus maze to infer whether these manipulations affected anxiety-like behavior. Finally, we also examined whether brain injury disrupts the ceramide/sphingolipid lipid signaling system and if DAGL-β deletion offers protection. Results: TBI disrupted all measures of neurological motor function and reduced body weight, but did not affect body temperature or performance in common assays used to infer anxiety. TBI also impaired performance in MWM Fixed Platform and Reversal tasks, but did not affect cued MWM performance. Although no differences were found between DAGL-β(−/−) and -β(+/+) mice in any of these measures, male DAGL-β(−/−) mice displayed an unexpected survival-protective phenotype, which persisted at increased injury severities. In contrast, TBI did not elicit mortality in female mice regardless of genotype. TBI also produced significant changes in sphingolipid profiles (a family of lipids, members of which have been linked to both apoptotic and antiapoptotic pathways), in which DAGL-β deletion modestly altered levels of select species. Conclusions: These findings indicate that although DAGL-β does not play a necessary role in TBI-induced cognitive and neurological function, it appears to contribute to the increased vulnerability of male mice to TBI-induced mortality, whereas female mice show high survival rates irrespective of DAGL-β expression.

The first generation of CB(1) positive allosteric modulators (e.g., ZCZ011) featured a 3-nitroalkyl-2-phenyl-indole structure. Although a small number of drugs include the nitro group, it is generally not regarded as being “drug-like”, and this is particularly true for aliphatic nitro groups. There are very few case studies where an appropriate bioisostere replaced a nitro group that had a direct role in binding. This may be indicative of the difficulty of replicating its binding interactions. Herein, we report the design and synthesis of ligands targeting the allosteric binding site on the CB(1) cannabinoid receptor, in which a CF(3) group successfully replaced the aliphatic NO(2). In general, the CF(3)-bearing compounds were more potent than their NO(2) equivalents and also showed improved in vitro metabolic stability. The CF(3) analogue (1) with the best balance of properties was selected for further pharmacological evaluation. Pilot in vivo studies showed that (±)-1 has similar activity to (±)-ZCZ011, with both showing promising efficacy in a mouse model of neuropathic pain.

Background Although paclitaxel is an effective chemotherapeutic agent used to treat multiple types of cancer (e.g. breast, ovarian, neck and lung), it also elicits paclitaxel-induced peripheral neuropathy (PIPN), which represents a major dose-limiting side effect of this drug. Methods As the endogenously produced N-acylethanolamine, palmitoylethanolamide (PEA), reverses paclitaxel-induced mechanical hypersensitivity in mice, the main goals of this study were to examine if paclitaxel affects levels of endogenous PEA in the spinal cord of mice and whether exogenous administration of PEA provides protection from the occurrence of paclitaxel-induced mechanical hypersensitivity. We further examined whether inhibition of N-acylethanolamine-hydrolysing acid amidase (NAAA), a hydrolytic PEA enzyme, would offer protection in mouse model of PIPN. Results Paclitaxel reduced PEA levels in the spinal cord, suggesting that dysregulation of this lipid signalling system may contribute to PIPN. Consistent with this idea, repeated administration of PEA partially prevented the paclitaxel-induced mechanical hypersensitivity. We next evaluated whether the selective NAAA inhibitor, AM9053, would prevent paclitaxel-induced mechanical hypersensitivity in mice. Acute administration of AM9053 dose-dependently reversed mechanical hypersensitivity through a PPAR-α mechanism, whereas repeated administration of AM9053 fully prevented the development of PIPN, without any evidence of tolerance. Moreover, AM9053 produced a conditioned place preference in paclitaxel-treated mice, but not in control mice. This pattern of findings suggests a lack of intrinsic rewarding effects, but a reduction in the pain aversiveness induced by paclitaxel. Finally, AM9053 did not alter paclitaxel-induced cytotoxicity in lung tumour cells. Conclusions Collectively, these studies suggest that NAAA represents a promising target to treat and prevent PIPN. Significance The present study demonstrates that the chemotherapeutic paclitaxel alters PEA levels in the spinal cord, whereas repeated exogenous PEA administration moderately alleviates PIPN in mice. Additionally, targeting NAAA, PEA's hydrolysing enzyme with a selective compound AM9053 reverses and prevents the PIPN via the PPAR-α mechanism. Overall, the data suggest that selective NAAA inhibitors denote promising future therapeutics to mitigate and prevent PIPN.

N-acylethanolamines (NAEs), which include the endocannabinoid anandamide, represent an important family of signaling lipids in the brain. The lack of chemical probes that modulate NAE biosynthesis in living systems hamper the understanding of the biological role of these lipids. Using a high-throughput screen, chemical proteomics and targeted lipidomics, we report here the discovery and characterization of LEI-401 as a CNS-active N-acylphosphatidylethanolamine phospholipase D (NAPE-PLD) inhibitor. LEI-401 reduced NAE levels in neuroblastoma cells and in the brain of freely moving mice, but not in NAPE-PLD KO cells and mice, respectively. LEI-401 activated the hypothalamus–pituitary–adrenal axis and impaired fear extinction, thereby emulating the effect of a cannabinoid CB1 receptor antagonist, which could be reversed by a fatty acid amide hydrolase inhibitor. Our findings highlight the distinctive role of NAPE-PLD in NAE biosynthesis in the brain and suggest the presence of an endogenous NAE tone controlling emotional behavior.

Although paclitaxel effectively treats various cancers, its debilitating peripheral neuropathic pain side effects often persist long after treatment has ended. Therefore, a compelling need exists for the identification of novel pharmacologic strategies to mitigate this condition. As inhibitors of monoacylglycerol lipase (MAGL), the primary hydrolytic enzyme of the endogenous cannabinoid, 2-arachidonyolglycerol, produces antinociceptive effects in numerous rodent models of pain, we investigated whether inhibitors of this enzyme (i.e., JZL184 and MJN110) would reverse paclitaxel-induced mechanical allodynia in mice. These drugs dose dependently reversed allodynia with respective ED(50) values (95% confidence limit) of 8.4 (5.2–13.6) and 1.8 (1.0–3.3) mg/kg. Complementary genetic and pharmacologic approaches revealed that the antiallodynic effects of each drug require both cannabinoid receptors, CB(1) and CB(2). MJN110 reduced paclitaxel-mediated increased expression of monocyte chemoattractant protein-1 (MCP-1, CCL2) and phospho-p38 MAPK in dorsal root ganglia as well as MCP-1 in spinal dorsal horn. Whereas the antinociceptive effects of high dose JZL184 (40 mg/kg) underwent tolerance following 6 days of repeated dosing, repeated administration of a threshold dose (i.e., 4 mg/kg) completely reversed paclitaxel-induced allodynia. In addition, we found that the administration of MJN110 to control mice lacked intrinsic rewarding effects in the conditioned place preference (CPP) paradigm. However, it produced a CPP in paclitaxel-treated animals, suggesting a reduced paclitaxel-induced aversive state. Importantly, JZL184 did not alter the antiproliferative and apoptotic effects of paclitaxel in A549 and H460 non-small cell lung cancer cells. Taken together, these data indicate that MAGL inhibitors reverse paclitaxel-induced neuropathic pain without interfering with chemotherapeutic efficacy.

In the present study, we examined whether LDK1258, which produces strong CB(1) receptor allosteric effects in in vitro assays, would elicit in vivo effects consistent with allosteric activity. In initial studies, LDK1258 reduced food consumption and elicited delayed antinociceptive effects in the chronic constrictive injury of the sciatic nerve (CCI) model of neuropathic pain, which unexpectedly emerged 4 h post-injection. UPLC-MS/MS analysis quantified significant levels of LDK1258 in both blood and brain tissue at 30 min post-administration that remained stable up to 4 h. The observation that LDK1258 also produced respective antinociceptive and anorectic effects in rimonabant-treated wild type mice and CB(1) (−/−) mice suggests an off-target mechanism of action. Likewise, LDK1258 produced a partial array of common cannabimimetic effects in the tetrad assay, which were not CB(1) receptor mediated. Additionally, LDK1258 did not substitute for the CB(1) receptor orthosteric agonists CP55,940 or anandamide in the drug discrimination paradigm. In other in vivo assays sensitive to CB(1) receptor allosteric modulators, LDK1258 failed to shift the dose-response curves of either CP55,940 or anandamide in producing thermal antinociception, catalepsy, or hypothermia, and did not alter the generalization curve of either drug in the drug discrimination assay. Thus, this battery of tests yielded results demonstrating that LDK1258 produces antinociceptive effects in the CCI model of neuropathic pain, anorectic effects, and other in vivo pharmacological effects in a manner inconsistent with CB(1) receptor allosterism. More generally, this study offers a straightforward screening assay to determine whether newly synthesized CB(1) receptor allosteric modulators translate to the whole animal.

Chemotherapy-induced peripheral neuropathy (CIPN) represents a serious complication associated with antineoplastic drugs. Although there are no medications available that effectively prevent CIPN, many classes of drugs have been used to treat this condition, including anticonvulsants, serotonin and noradrenaline reuptake inhibitors, and opioids. However, these therapeutic options yielded inconclusive results in CIPN clinical trials and produced assorted side effects with their prolonged use. Thus, there is an urgent need to develop efficacious and safe treatments for CIPN. In this report, we tested whether the endogenous lipid palmitoylethanolamide (PEA) alone or in combination with the anticonvulsant gabapentin would reduce allodynia in a mouse paclitaxel model of CIPN. Gabapentin and PEA reversed paclitaxel-induced allodynia with respective ED50 doses (95% confidence interval) of 67.4 (61.52–73.94) and 9.2 (8.39–10.16) mg/kg. Isobolographic analysis of these drugs in combination revealed synergistic antiallodynic effects. The PPAR-α antagonist receptor antagonist GW6471 [N-((2S)-2-(((1Z)-1-methyl-3-oxo-3-(4-(trifluoromethyl)phenyl)prop-1-enyl)amino)-3-(4-(2-(5-methyl-2-phenyl-1,3-oxazol-4-yl)ethoxy)phenyl)propyl)propanamide] completely blocked the antinociceptive effects of PEA. In addition, PEA administered via intraplantar injection into a paw, intrathecal injection, and intracerebroventricular injection reversed paclitaxel-induced allodynia, suggesting that it may act at multiple sites in the neuroaxis and periphery. Finally, repeated administration of PEA (30 mg/kg, 7 days) preserved the antiallodynic effects with no evidence of tolerance. These findings taken together suggest that PEA possesses potential to treat peripheral neuropathy in cancer patients undergoing chemotherapy.

Cigarette smokers with brain damage involving the insular cortex display cessation of tobacco smoking, suggesting that this region may contribute to nicotine addiction. In the present study, we speculated that molecules in the insular cortex that are sensitive to experimental traumatic brain injury (TBI) in mice might provide leads to ameliorate nicotine addiction. Using targeted lipidomics, we found that TBI elicited substantial increases of a largely uncharacterized lipid, N-acyl-glycine, N-oleoyl-glycine (OlGly), in the insular cortex of mice. We then evaluated whether intraperitoneal administration of OlGly would alter withdrawal responses in nicotine-dependent mice as well as the rewarding effects of nicotine, as assessed in the conditioned place preference paradigm (CPP). Systemic administration of OlGly reduced mecamylamine-precipitated withdrawal responses in nicotine-dependent mice and prevented nicotine CPP. However, OlGly did not affect morphine CPP, demonstrating a degree of selectivity. Our respective in vitro and in vivo observations that OlGly activated peroxisome proliferator-activated receptor alpha (PPAR-α) and the PPAR-α antagonist GW6471 prevented the OlGly-induced reduction of nicotine CPP in mice suggests that this lipid acts as a functional PPAR-α agonist to attenuate nicotine reward. These findings raise the possibility that the long chain fatty acid amide OlGly may possess efficacy in treating nicotine addiction.

In the present study, we examined whether LDK1258, which produces strong CB1 receptor allosteric effects in in vitro assays, would elicit in vivo effects consistent with allosteric activity. In initial studies, LDK1258 reduced food consumption and elicited delayed antinociceptive effects in the chronic constrictive injury of the sciatic nerve (CCI) model of neuropathic pain, which unexpectedly emerged 4 h post-injection. UPLC-MS/MS analysis quantified significant levels of LDK1258 in both blood and brain tissue at 30 min post-administration that remained stable up to 4 h. The observation that LDK1258 also produced respective antinociceptive and anorectic effects in rimonabant-treated wild type mice and CB1 (−/−) mice suggests an off-target mechanism of action. Likewise, LDK1258 produced a partial array of common cannabimimetic effects in the tetrad assay, which were not CB1 receptor mediated. Additionally, LDK1258 did not substitute for the CB1 receptor orthosteric agonists CP55,940 or anandamide in the drug discrimination paradigm. In other in vivo assays sensitive to CB1 receptor allosteric modulators, LDK1258 failed to shift the dose-response curves of either CP55,940 or anandamide in producing thermal antinociception, catalepsy, or hypothermia, and did not alter the generalization curve of either drug in the drug discrimination assay. Thus, this battery of tests yielded results demonstrating that LDK1258 produces antinociceptive effects in the CCI model of neuropathic pain, anorectic effects, and other in vivo pharmacological effects in a manner inconsistent with CB1 receptor allosterism. More generally, this study offers a straightforward screening assay to determine whether newly synthesized CB1 receptor allosteric modulators translate to the whole animal.

Cessation from prolonged use of ∆(9)-tetrahydrocannabinol (THC), the primary active compound responsible for the cannabimimetic effects of cannabis results in a mild to moderate withdrawal syndrome in humans and laboratory animals. Whereas manipulations of the endogenous cannabinoid system (e.g., cannabinoid receptors and endocannabinoid regulating enzymes) alter nicotine withdrawal, in this study we asked the reciprocal question. Do nicotinic acetylcholine receptors (nAChRs) modulate THC withdrawal? To assess the role of different nAChR subtypes in THC withdrawal, we used transgenic mouse, preclinical pharmacological, and human genetic correlation approaches. Our findings show that selective α3β4* nAChR antagonist, AuIB, and α3β4* nAChR partial agonist, AT-1001, dose-dependently attenuated somatic withdrawal signs in THC-dependent mice that were challenged with the cannabinoid-1 receptor antagonist rimonabant. Additionally, THC-dependent α5 and α6 nAChR knockout (KO) mice displayed decreased rimonabant precipitated somatic withdrawal signs compared with their wild-type counterparts. In contrast, β2 and α7 nAChR KO mice showed no alterations in THC withdrawal signs. Moreover, deletion of β nAChR did not alter the reduced expression of somatic signs by the preferred α6β4* antagonist, BulA[T5A;P60]. Finally, the human genetic association studies indicated that variations in the genes that code for the α5, α3, β4, and α6 nAChRs were associated with cannabis disorder phenotypes. Overall, these findings suggest that α3β4* and α6β4* nAChR subtypes represent viable targets for the development of medications to counteract THC dependence.

New glucuronosyldiacylglycerol (GlcADG) analogues based on a 2-O-β-d-glucopyranosyl-sn-glycerol scaffold and carrying one or two acyl chains of different lengths have been synthesized as phosphatidylinositol 3-phosphate (PI3P) mimics targeting the protein kinase Akt. The Akt inhibitory effect of the prepared compounds was assayed using an in vitro kinase assay. The antiproliferative activity of the compounds was tested in the human ovarian carcinoma IGROV-1 cell line in which we found that two of them could inhibit proliferation, in keeping with the target inhibitory effect.

A great need exists for the development of new medications to treat pain resulting from various disease states and types of injury. Given that the endogenous cannabinoid (that is, endocannabinoid) system modulates neuronal and immune cell function, both of which play key roles in pain, therapeutics targeting this system hold promise as novel analgesics. Potential therapeutic targets include the cannabinoid receptors, type 1 and 2, as well as biosynthetic and catabolic enzymes of the endocannabinoids N-arachidonoylethanolamine and 2-arachidonoylglycerol. Notably, cannabinoid receptor agonists as well as inhibitors of endocannabinoid-regulating enzymes fatty acid amide hydrolase and monoacylglycerol lipase produce reliable antinociceptive effects, and offer opioid-sparing antinociceptive effects in myriad preclinical inflammatory and neuropathic pain models. Emerging clinical studies show that ‘medicinal’ cannabis or cannabinoid-based medications relieve pain in human diseases such as cancer, multiple sclerosis, and fibromyalgia. However, clinical data have yet to demonstrate the analgesic efficacy of inhibitors of endocannabinoid-regulating enzymes. Likewise, the question of whether pharmacotherapies aimed at the endocannabinoid system promote opioid-sparing effects in the treatment of pain reflects an important area of research. Here we examine the preclinical and clinical evidence of various endocannabinoid system targets as potential therapeutic strategies for inflammatory and neuropathic pain conditions.

Diacylglycerol lipase-beta (DAGLβ) hydrolyzes arachidonic acid (AA)-containing diacylglycerols to produce bioactive lipids including endocannabinoids and AA-derived eicosanoids involved in regulation of inflammatory signaling. Previously, we demonstrated that DAGLβ inactivation using the triazole urea inhibitor KT109 blocked macrophage inflammatory signaling and reversed allodynic responses of mice in inflammatory and neuropathic pain models. Here, we tested whether we could exploit the phagocytic capacity of macrophages to localize delivery of DAGLβ inhibitors to these cells in vivo using liposome encapsulated KT109. We used DAGLβ-tailored activity-based probes and chemical proteomic methods to measure potency and selectivity of liposomal KT109 in macrophages and tissues from treated mice. Surprisingly, delivery of ~5 μg of liposomal KT109 was sufficient to achieve ~80% inactivation of DAGLβ in macrophages with no apparent activity in other tissues in vivo. Our macrophage-targeted delivery resulted in a >100-fold enhancement in antinociceptive potency compared with free compound in a mouse inflammatory pain model. Our studies describe a novel anti-inflammatory strategy that is achieved by targeted in vivo delivery of DAGLβ inhibitors to macrophages.

Diacylglycerol lipase (DAGL) α and β, the major biosynthetic enzymes of the endogenous cannabinoid (endocannabinoid) 2-arachidonylglycerol (2-AG), are highly expressed in the nervous system and immune system, respectively. Genetic deletion or pharmacological inhibition of DAGL-β protects against lipopolysaccharide (LPS)-induced inflammatory responses in mouse peritoneal macrophages and reverses LPS-induced allodynia in mice. To gain insight into the contribution of DAGL-α in LPS-induced allodynia, we tested global knockout mice as well as DO34, a dual DAGL-α/β inhibitor. Intraperitoneal administration of DO34 (30 mg/kg) significantly decreased whole-brain levels of 2-AG (∼83%), anandamide (∼42%), and arachidonic acid (∼58%). DO34 dose-dependently reversed mechanical and cold allodynia, and these antinociceptive effects did not undergo tolerance after 6 days of repeated administration. In contrast, DO34 lacked acute thermal antinociceptive, motor, and hypothermal pharmacological effects in naive mice. As previously reported, DAGL-β (-/-) mice displayed a protective phenotype from LPS-induced allodynia. However, DAGL-α (-/-) mice showed full allodynic responses, similar to their wild-type littermates. Interestingly, DO34 (30 mg/kg) fully reversed LPS-induced allodynia in DAGL-α (+/+) and (-/-) mice, but did not affect the antinociceptive phenotype of DAGL-β (-/-) mice in this model, indicating a DAGL-α-independent site of action. These findings suggest that DAGL-α and DAGL-β play distinct roles in LPS-induced nociception. Whereas DAGL-α appears to be dispensable for the development and expression of LPS-induced nociception, DAGL-β inhibition represents a promising strategy to treat inflammatory pain.

Recently, alpha 7 nicotinic acetylcholine receptors (nAChRs), primarily activated by binding of orthosteric agonists, represent a target for anti-inflammatory and analgesic drug development. These receptors may also be modulated by positive allosteric modulators (PAMs), ago-allosteric ligands (ago-PAMs), and alpha 7-silent agonists. Activation of 00 nAChRs has been reported to increase the brain levels of endogenous ligands for nuclear peroxisome proliferator-activated receptors type-alpha (PPAR-alpha), palmitoylethanolamide (PEA) and oleoylethanolamide (OEA), in a Ca2+-dependent manner. Here, we investigated potential crosstalk between alpha 7 nAChR and PPAR-alpha, using the formalin test, a mouse model of tonic pain. Using pharmacological and genetic approaches, we found that PNU282987, a full alpha 7 agonist, attenuated formalin-induced nociceptive behavior in alpha 7 -dependent manner. Interestingly, the selective PPAR-alpha antagonist GW6471 blocked the antinociceptive effects of PNU282987, but did not alter the antinociceptive responses evoked by the alpha 7 nAChR PAM PNU120596, ago-PAM GAT107, and silent agonist NS6740. Moreover, GW6471 administered systemically or spinally, but not via the intraplantar surface of the formalin-injected paw blocked PNU282987-induced antinociception. Conversely, exogenous administration of the naturally occurring PPAR-alpha agonist PEA potentiated the antinociceptive effects of PNU282987. In contrast, the cannabinoid 031 antagonist rimonabant and the CB2 antagonist SR144528 failed to reverse the antinociceptive effects of PNU282987. These findings suggest that PPAR-alpha plays a key role in a putative antinociceptive alpha 7 nicotinic signaling pathway. United States Department of Health & Human Services National Institutes of Health (NIH) - USA - GM57481 - R01 CA206028 United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Cancer Institute (NCI) - R01CA206028 United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Institute of General Medical Sciences (NIGMS) - R01GM057481 United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Institute on Drug Abuse (NIDA) European Commission - T32DA007027

New sulfoquinovose analogues of phosphatidylinositol 3-phosphate have been synthesised based on a sulfoquinovose scaffold as potential protein kinase B (PKB) inhibitors. The synthetic strategy involved the introduction into glucose of a thioacetate group at the 6-position and of an azide group at the anomeric position as precursors of the sulfonate and phosphoramidate moieties present in the final compounds. The synthesised compounds were tested in vitro on isolated PKB by means of ELISA assays and for their anti-proliferative activity against the human ovarian carcinoma cell line IGROV-1. Sulfoquinovose derivatives 2b and 2c showed inhibitory activity in the low micromolar range.

The serine-threonine protein kinase Akt, also known as protein kinase B, is a key component of the phosphoinositide 3-kinase (PI3K)-Akt-mTOR axis. Deregulated activation of this pathway is frequent in human tumors and Akt-dependent signaling appears to be critical in cell survival. PI3K activation generates 3-phosphorylated phosphatidylinositols that bind Akt pleckstrin homology (PH) domain. The blockage of Akt PH domain/phosphoinositides interaction represents a promising approach to interfere with the oncogenic potential of over-activated Akt. In the present study, phosphatidyl inositol mimics based on a β-glucoside scaffold have been synthesized as Akt inhibitors. The compounds possessed one or two lipophilic moieties of different length at the anomeric position of glucose, and an acidic or basic group at C-6. Docking studies, ELISA Akt inhibition assays, and cellular assays on different cell models highlighted 1-O-octadecanoyl-2-O-β-d-sulfoquinovopyranosyl-sn-glycerol as the best Akt inhibitor among the synthesized compounds, which could be considered as a lead for further optimization in the design of Akt inhibitors.

We previously demonstrated that the intraperitoneal administration of palmitoylethanolamide (PEA) in mice with chronic constriction injury of the sciatic nerve evoked a relief of both thermal hyperalgesia and mechanical allodynia in neuropathic mice. Since diabetic neuropathy is one of the most common long-term complications of diabetes, we explored the ability of PEA to also relief this kind of chronic pain, employing the well established streptozotocin-induced animal model of type 1 diabetes. Our findings demonstrated that PEA relieves mechanical allodynia, counteracts nerve growth factor deficit, improves insulin level, preserves Langerhans islet morphology reducing the development of insulitis in diabetic mice. These results suggest that PEA could be effective in type 1-diabetic patients not only as pain reliever but also in controlling the development of pathology.

We show here that a mild sterile inflammation induced by the endotoxin lipopolysaccharide (LPS), in a neuron/astrocyte/microglial cortical network, modulates neuronal excitability and can initiate long-duration burst events resembling epileptiform seizures, a recognized feature of various central nervous neurodegenerative, neurological and acute systemic diseases associated with neuroinflammation. To study this action, we simultaneously analyzed the reverberating bursting activity of a hundred neurons by using in vitro multi-electrode array (MEA) methods. ~5 hours after LPS application, we observed a net increase in the average number of spikes elicited in engaged cells and within each burst, but no changes neither in spike waveforms nor in burst rate. This effect was characterized by a slow, two-fold exponential increase of the burst duration and the appearance of rarely occurring long-burst events that were never seen during control recordings. These changes and the time-course of microglia-released proinflammatory cytokine, tumor necrosis factor-alpha (TNF-α), were blocked by pre-treatment with 50 nM minocycline, an established anti-inflammatory agent which was inactive when applied alone. Assay experiments also revealed that application of 60 pM exogenous TNF-α after 12-15 h, produced non-washable changes of neuronal excitability, completely different from those induced by LPS, suggesting that TNF-α release alone was not responsible for our observed findings. Our results indicate that the link between neuroinflammation and hyperexcitability can be unveiled by studying the long-term activity of in vitro neuronal/astrocyte/microglial networks.