Passive immunotherapy for N-truncated tau ameliorates the cognitive deficits in two mouse Alzheimer's disease models

Abstract Clinical and neuropathological studies have shown that tau pathology better correlates with the severity of dementia than amyloid plaque burden, making tau an attractive target for the cure of Alzheimer's disease. We have explored whether passive immunization with the 12A12 monoclonal antibody (26–36aa of tau protein) could improve the Alzheimer's disease phenotype of two well-established mouse models, Tg2576 and 3xTg mice. 12A12 is a cleavage-specific monoclonal antibody which selectively binds the pathologically relevant neurotoxic NH226-230 fragment (i.e. NH2htau) of tau protein without cross-reacting with its full-length physiological form(s). We found out that intravenous administration of 12A12 monoclonal antibody into symptomatic (6 months old) animals: (i) reaches the hippocampus in its biologically active (antigen-binding competent) form and successfully neutralizes its target; (ii) reduces both pathological tau and amyloid precursor protein/amyloidβ metabolisms involved in early disease-associated synaptic deterioration; (iii) improves episodic-like type of learning/memory skills in hippocampal-based novel object recognition and object place recognition behavioural tasks; (iv) restores the specific up-regulation of the activity-regulated cytoskeleton-associated protein involved in consolidation of experience-dependent synaptic plasticity; (v) relieves the loss of dendritic spine connectivity in pyramidal hippocampal CA1 neurons; (vi) rescues the Alzheimer's disease-related electrophysiological deficits in hippocampal long-term potentiation at the CA3-CA1 synapses; and (vii) mitigates the neuroinflammatory response (reactive gliosis). These findings indicate that the 20–22 kDa NH2-terminal tau fragment is crucial target for Alzheimer's disease therapy and prospect immunotherapy with 12A12 monoclonal antibody as safe (normal tau-preserving), beneficial approach in contrasting the early Amyloidβ-dependent and independent neuropathological and cognitive alterations in affected subjects

A novel fluorophosphonate inhibitor of the biosynthesis of the endocannabinoid 2-arachidonoylglycerol with potential anti-obesity effects

Background and Purpose The development of potent and selective inhibitors of the biosynthesis of the endocannabinoid 2-arachidonoylglycerol (2-AG) via DAG lipases (DAGL) α and β is just starting to be considered as a novel and promising source of pharmaceuticals for the treatment of disorders that might benefit from a reduction in endocannabinoid tone, such as hyperphagia in obese subjects. Experimental Approach Three new fluorophosphonate compounds O-7458, O-7459 and O-7460 were synthesized and characterized in various enzymatic assays. The effects of O-7460 on high-fat diet intake were tested in mice. Key Results Of the new compounds, O-7460 exhibited the highest potency (IC50 = 690 nM) against the human recombinant DAGLα, and selectivity (IC50 > 10 μM) towards COS-7 cell and human monoacylglycerol lipase (MAGL), and rat brain fatty acid amide hydrolase. Competitive activity-based protein profiling confirmed that O-7460 inhibits mouse brain MAGL only at concentrations ≥10 μM, and showed that this compound has only one major ‘off-target’, that is, the serine hydrolase KIAA1363. O-7460 did not exhibit measurable affinity for human recombinant CB1 or CB2 cannabinoid receptors (Ki > 10 μM). In mouse neuroblastoma N18TG2 cells stimulated with ionomycin, O-7460 (10 μM) reduced 2-AG levels. When administered to mice, O-7460 dose-dependently (0–12 mg·kg−1, i.p.) inhibited the intake of a high-fat diet over a 14 h observation period, and, subsequently, slightly but significantly reduced body weight. Conclusions and Implications O-7460 might be considered a useful pharmacological tool to investigate further the role played by 2-AG both in vitro and in vivo under physiological as well as pathological conditions

Satiety factor oleoylethanolamide recruits the brain histaminergic system to inhibit food intake

Key factors driving eating behavior are hunger and satiety, which are controlled by a complex interplay of central neurotransmitter systems and peripheral stimuli. The lipid-derived messenger oleoylethanolamide (OEA) is released by enterocytes in response to fat intake and indirectly signals satiety to hypothalamic nuclei. Brain histamine is released during the appetitive phase to provide a high level of arousal in anticipation of feeding, and mediates satiety. However, despite the possible functional overlap of satiety signals, it is not known whether histamine participates in OEA-induced hypophagia. Using different experimental settings and diets, we report that the anorexiant effect of OEA is significantly attenuated in mice deficient in the histamine-synthesizing enzyme histidine decarboxylase (HDC-KO) or acutely depleted of histamine via interocerebroventricular infusion of the HDC blocker α-fluoromethylhistidine (α-FMH). α-FMH abolished OEA-induced early occurrence of satiety onset while increasing histamine release in the CNS with an H3 receptor antagonist-increased hypophagia. OEA augmented histamine release in the cortex of fasted mice within a time window compatible to its anorexic effects. OEA also increased c-Fos expression in the oxytocin neurons of the paraventricular nuclei of WT but not HDC-KO mice. The density of c-Fos immunoreactive neurons in other brain regions that receive histaminergic innervation and participate in the expression of feeding behavior was comparable in OEA-treated WT and HDC-KO mice. Our results demonstrate that OEA requires the integrity of the brain histamine system to fully exert its hypophagic effect and that the oxytocin neuron-rich nuclei are the likely hypothalamic area where brain histamine influences the central effects of OEA

Paternal alcohol exposure in mice alters brain NGF and BDNF and increases ethanol-elicited preference in male offspring

Ethanol (EtOH) exposure during pregnancy induces cognitive and physiological deficits in the offspring. However, the role of paternal alcohol exposure (PAE) on offspring EtOH sensitivity and neurotrophins has not received much attention. The present study examined whether PAE may disrupt nerve growth factor (NGF) and/or brain-derived neurotrophic factor (BDNF) and affect EtOH preference/rewarding properties in the male offspring. CD1 sire mice were chronically addicted for EtOH or administered with sucrose. Their male offsprings when adult were assessed for EtOH preference by a conditioned place preference paradigm. NGF and BDNF, their receptors (p75NTR, TrkA and TrkB), dopamine active transporter (DAT), dopamine receptors D1 and D2, pro-NGF and pro-BDNF were also evaluated in brain areas. PAE affected NGF levels in frontal cortex, striatum, olfactory lobes, hippocampus and hypothalamus. BDNF alterations in frontal cortex, striatum and olfactory lobes were found. PAE induced a higher susceptibility to the EtOH rewarding effects mostly evident at the lower concentration (0.5 g/kg) that was ineffective in non-PAE offsprings. Moreover, higher ethanol concentrations (1.5 g/kg) produced an aversive response in PAE animals and a significant preference in non-PAE offspring. PAE affected also TrkA in the hippocampus and p75NTR in the frontal cortex. DAT was affected in the olfactory lobes in PAE animals treated with 0.5 g/kg of ethanol while no differences were found on D1/D2 receptors and for pro-NGF or pro-BDNF. In conclusion, this study shows that: PAE affects NGF and BDNF expression in the mouse brain; PAE may induce ethanol intake preference in the male offspring

Behavioral effects of long-term administration of palmitoylethanolamide on Tg2576 mice

Aim: To date, pharmacological approaches to treat dementia and particularly Alzheimer disease (AD) remain uncertain and unclear. In this context, palmitoylethanolamide (PEA) has been emerging as an important analgesic, anti-inflammatory and neuroprotective mediator, acting at several molecular targets in both central and peripheral nervous systems as well as immune cells, and has demonstrated high safety and tolerability. PEA is present in certain foods we use every day such as egg yolk, corn, peanut and soy oils and is also produced by many cells in our organism. It can be found in high concentrations in brain tissues and is synthesized starting by lipid components of the cellular membranes. In the present study, we sought to investigate the behavioral modifications potentially induced by a chronic administration of ultra-micronized PEA (i.e., a micrometer-sized crystalline form that improves both its pharmacokinetics and bioavailability) for 6-months in transgenic mice expressing mutant APP (Tg2576 mice). These mice express high levels of mutated human APP and with advancing age develop both amyloid peptide accumulation and amyloid plaques in the brain, as well as behavioral and cognitive deficits; thus, they represent a widely accepted animal model of AD. Methods: The 6-month administration of PEA in Tg2576 mice and the wild-type (WT) control group was via a subcutaneous (s.c.) delivery system. Mice were subjected to s.c. implantation of PEA or placebo pellets at 6 months of age. PEA effects on motor, cognitive and emotional performances were monitored longitudinally, by a battery of behavioral tasks, within three different ages, corresponding to a pre-symptomatic phase (T0 = 3 months), a mild-symptomatic phase (T1 = 6.5 months) and a fully symptomatic phase (T2 = 11-12 months; ie., at the end of the chronic supplementation). All mice underwent the behavioral assessment by using the following battery of validated tests: Elevated Plus Maze (EPM), to assess anxiety levels and locomotor skills; Rotarod Test (RT), to assess motor coordination skills; Y-Maze Spontaneous Alternation Test (Y-Maze), to assess working memory skills; Novel Object Recognition Test (NORT), to assess mnestic and discriminative skills; Tail Suspension Test (TST), to assess depressive behaviors. Results: Behavioral analyses performed on our mice demonstrate that chronic PEA supplementation exerts beneficial effects on NORT mnesic performances of Tg2576 mice at T2. Specifically, in Tg2576 mice chronic PEA supplementation restored the novelty recognition memory impaired during the fully symptomatic phase, while did not affect working memory, motor coordination, anxiety, and depressive-like alterations. No PEA effects were observed in WT mice. Conclusions: PEA is able to counteract specific hippocampal-dependent mnesic deficits typical of AD. Our data suggest the likely therapeutic potential of ultra-micronized PEA as an early treatment in AD. These findings should be further investigated to increase knowledge of the effects of PEA as a safe and low-cost nutraceutical tool useful to improve quality of life in AD

Oleoylethanolamide: A Novel Potential Pharmacological Alternative to Cannabinoid Antagonists for the Control of Appetite

The initial pharmaceutical interest for the endocannabinoid system as a target for antiobesity therapies has been restricted by the severe adverse effects of the CB1 antagonist rimonabant. This study points at oleoylethanolamide (OEA), a monounsaturated analogue, and functional antagonist of anandamide, as a potential and safer antiobesity alternative to CB1 antagonism. Mice treated with equal doses (5 or 10 mg/kg, i.p.) of OEA or rimonabant were analyzed for the progressive expression of spontaneous behaviors (eating, grooming, rearing, locomotion, and resting) occurring during the development of satiety, according to the paradigm called behavioral satiety sequence (BSS). Both drugs reduced food (wet mash) intake to a similar extent. OEA treatment decreased eating activity within the first 30 min and caused a temporary increase of resting time that was not accompanied by any decline of horizontal, vertical and total motor activity. Besides decreasing eating activity, rimonabant caused a marked increase of the time spent grooming and decreased horizontal motor activity, alterations that might be indicative of aversive nonmotivational effects on feeding. These results support the idea that OEA suppresses appetite by stimulating satiety and that its profile of action might be predictive of safer effects in humans as a novel antiobesity treatment

Lack of cyclin D3 induces skeletal muscle fiber-type shifting, increased endurance performance and hypermetabolism

Abstract The mitogen-induced D-type cyclins (D1, D2 and D3) are regulatory subunits of the cyclin-dependent kinases CDK4 and CDK6 that drive progression through the G1 phase of the cell cycle. In skeletal muscle, cyclin D3 plays a unique function in controlling the proliferation/differentiation balance of myogenic progenitor cells. Here, we show that cyclin D3 also performs a novel function, regulating muscle fiber type-specific gene expression. Mice lacking cyclin D3 display an increased number of myofibers with higher oxidative capacity in fast-twitch muscle groups, primarily composed of myofibers that utilize glycolytic metabolism. The remodeling of myofibers toward a slower, more oxidative phenotype is accompanied by enhanced running endurance and increased energy expenditure and fatty acid oxidation. In addition, gene expression profiling of cyclin D3−/− muscle reveals the upregulation of genes encoding proteins involved in the regulation of contractile function and metabolic markers specifically expressed in slow-twitch and fast-oxidative myofibers, many of which are targets of MEF2 and/or NFAT transcription factors. Furthermore, cyclin D3 can repress the calcineurin- or MEF2-dependent activation of a slow fiber-specific promoter in cultured muscle cells. These data suggest that cyclin D3 regulates muscle fiber type phenotype, and consequently whole body metabolism, by antagonizing the activity of MEF2 and/or NFAT

Chronic administration of palmitoylethanolamide counteracts cognitive decline in Tg2576 Mice

Palmitoylethanolamide (PEA) has been emerging as a safe and well tolerated analgesic, anti-inflammatory and neuroprotective mediator, acting at several molecular targets in the nervous system. PEA is present in foods, as egg yolk, corn, peanut and soy oil. It is synthesized from lipid components of cellular membranes and can be found in high concentrations in brain tissues. In this study, we evaluated the effects of a chronic (6 months) administration of ultra-micronized PEA on cognitive decline in transgenic Tg2576 (Tg) mice expressing mutant APP. When aged, Tg mice develop accumulation of amyloid peptide and amyloid plaques in the brain, as well as cognitive deficits, representing thus an animal model of AD. PEA administration was performed via a subcutaneous delivery system in Tg mice and wild-type control group (from 6 to 12 months of age). PEA effects on behavior were observed longitudinally in a pre-symptomatic phase (3 months), a mild-symptomatic phase (6.5 months) and a full-symptomatic phase (11-12 months). Behavioral assessment was performed by using the following validated tests: Elevated Plus Maze, Rotarod Test, Y-Maze Spontaneous Alternation Test, Novel Object Recognition Test, Tail Suspension Test and Morris Water Maze. PEA administration restored the novelty recognition memory of Tg mice during the full-symptomatic phase. PEA was able to counteract hippocampal- dependent mnesic deficits, suggesting the therapeutic potential for the early treatment of AD. Further in progress analyses involve histological evaluation of dendritic branching, spine number, amyloid plaques and glial reactivity in the hippocampal CA1. This research is aimed to increase knowledge of the effects of PEA as a safe and low-cost nutraceutical tool useful to improve quality of life in AD

Different Routes to Inhibit Fatty Acid Amide Hydrolase: Do All Roads Lead to the Same Place?

There is robust evidence indicating that enhancing the endocannabinoid (eCB) tone has therapeutic potential in several brain disorders. The inhibition of eCBs degradation by fatty acid amide hydrolase (FAAH) blockade, is the best-known option to increase N-acyl-ethanolamines-(NAEs)-mediated signaling. Here, we investigated the hypothesis that intranasal delivery is an effective route for different FAAH inhibitors, such as URB597 and PF-04457845. URB597 and PF-04457845 were subchronically administered in C57BL/6 male mice every other day for 20 days for overall 10 drug treatment, and compared for their ability to inhibit FAAH activity by the way of three different routes of administration: intranasal (i.n.), intraperitoneal (i.p.) and oral (p.o.). Lastly, we compared the efficacy of the three routes in terms of URB597-induced increase of NAEs levels in liver and in different brain areas. Results: We show that PF-04457845 potently inhibits FAAH regardless the route selected, and that URB597 was less effective in the brain after p.o. administration while reached similar effects by i.n. and i.p. routes. Intranasal URB597 delivery always increased NAEs levels in brain areas, whereas a parallel increase was not observed in the liver. By showing the efficacy of intranasal FAAH inhibition, we provide evidence that nose-to-brain delivery is a suitable alternative to enhance brain eCB tone for the treatment of neurodegenerative disorders and improve patients' compliance