Maternal obesity induces sex-specific changes in the endocannabinoid system of the hypothalamus and dorsal hippocampus of offspring associated with anxiety-like behavior in adolescent female rats.

Maternal obesity during perinatal period increases the risk of metabolic and behavioral deleterious outcomes in the offspring, since it is critical for brain development, maturation, and reorganization. These processes are highly modulated by the endocannabinoid system (ECS), which comprises the main lipid ligands anandamide and 2-arachidonoylglycerol, cannabinoid receptors 1 and 2 (CB1R and CB2R), and several metabolizing enzymes. The ECS is overactivated in obesity and it contributes to the physiological activity of the hypothalamus-pituitary-adrenal (HPA) axis, promoting stress relief. We have previously demonstrated that maternal high-fat diet during gestation and lactation programmed the food preference for fat in adolescent male offspring and adult male and female offspring. In the present study, we hypothesized that maternal diet-induced obesity would induce sex-specific changes of the ECS in the hypothalamus and dorsal hippocampus of rat offspring associated with dysregulation of the HPA axis and stress-related behavior in adolescence. Rat dams were fed a control (C) or an obesogenic high-fat high-sugar diet (OD) for nine weeks prior to mating and throughout gestation and lactation. Maternal obesity differentially altered the CB1R in the hypothalamus of neonate offspring, with significant increase in male but not in female pups, associated with decreased CB2R prior to obesity development. In adolescence, maternal obesity induced anxiety-like behavior only in adolescent females which was associated with increased content of CB1R in the dorsal hippocampus. Our findings suggest that the early origins of anxiety disorders induced by maternal exposome is associated with dysregulation of the brain ECS, with females being more susceptible.

Energization by multiple substrates and calcium challenge reveal dysfunctions in brain mitochondria in a model related to acute psychosis.

Schizophrenia etiology is unknown, nevertheless imbalances occurring in an acute psychotic episode are important to its development, such as alterations in cellular energetic state, REDOX homeostasis and intracellular Ca2+ management, all of which are controlled primarily by mitochondria. However, mitochondrial function was always evaluated singularly, in the presence of specific respiratory substrates, without considering the plurality of the electron transport system. In this study, mitochondrial function was analyzed under conditions of isolated or multiple respiratory substrates using brain mitochondria isolated from MK-801-exposed mice. Results showed a high H2O2 production in the presence of pyruvate/malate, with no change in oxygen consumption. In the condition of multiple substrates, however, this effect is lost. The analysis of Ca2+ retention capacity revealed a significant change in the uptake kinetics of this ion by mitochondria in MK-801-exposed animals. Futhermore, when mitochondria were exposed to calcium, a total loss of oxidative phosphorylation and an impressive increase in H2O2 production were observed in the condition of multiple substrates. There was no alteration in the activity of the antioxidant enzymes analyzed. The data demonstrate for the first time, in an animal model of psychosis, two important aspects (1) mitochondria may compensate deficiencies in a single mitochondrial complex when they oxidize several substrates simultaneously, (2) Ca2+ handling is compromised in MK-801-exposed mice, resulting in a loss of phosphorylative capacity and an increase in H2O2 production. These data favor the hypothesis that disruption of key physiological roles of mitochondria may be a trigger in acute psychosis and, consequently, schizophrenia.

Is Forced Swimming Immobility a Good Endpoint for Modeling Negative Symptoms of Schizophrenia? - Study of Sub-Anesthetic Ketamine Repeated Administration Effects.

Immobility time in the forced swimming has been described as analogous to emotional blunting or apathy and has been used for characterizing schizophrenia animal models. Several clinical studies support the use of NMDA receptor antagonists to model schizophrenia in rodents. Some works describe the effects of ketamine on immobility behavior but there is variability in the experimental design used leading to controversial results. In this study, we evaluated the effects of repeated administration of ketamine sub-anesthetic doses in forced swimming, locomotion in response to novelty and novel object recognition, aiming a broader evaluation of the usefulness of this experimental approach for modeling schizophrenia in mice. Ketamine (30 mg/kg/day i.p. for 14 days) induced a not persistent decrease in immobility time, detected 24h but not 72h after treatment. This same administration protocol induced a deficit in novel object recognition. No change was observed in mice locomotion. Our results confirm that repeated administration of sub-anesthetic doses of ketamine is useful in modeling schizophrenia-related behavioral changes in mice. However, the immobility time during forced swimming does not seem to be a good endpoint to evaluate the modeling of negative symptoms in NMDAR antagonist animal models of schizophrenia.

Social isolation leads to mild social recognition impairment and losses in brain cellularity.

Chronic social stress is a significant risk factor for several neuropsychiatric disorders, mainly major depressive disorder (MDD). In this way, patients with clinical depression may display many symptoms, including disrupted social behavior and anxiety. However, like many other psychiatric diseases, MDD has a very complex etiology and pathophysiology. Because social isolation is one of the multiple depression-inducing factors in humans, this study aims to understand better the link between social stress and MDD using an animal model based on social isolation after weaning, which is known to produce social stress in mice. We focused on cellular composition and white matter integrity to establish possible links with the abnormal social behavior that rodents isolated after weaning displayed in the three-chamber social approach and recognition tests. We used the isotropic fractionator method to assess brain cellularity, which allows us to robustly estimate the number of oligodendrocytes and neurons in dissected brain regions. In addition, diffusion tensor imaging (DTI) was employed to analyze white matter microstructure. Results have shown that post-weaning social isolation impairs social recognition and reduces the number of neurons and oligodendrocytes in important brain regions involved in social behavior, such as the anterior neocortex and the olfactory bulb. Despite the limitations of animal models of psychological traits, evidence suggests that behavioral impairments observed in patients might have similar biological underpinnings.

Age-dependent memory impairment induced by co-exposure to nicotine and a synthetic cannabinoid in mice.

Co-use of marijuana and tobacco products is the second most common drug combination among adolescents. Nicotine (NIC) and cannabinoid use during adolescence induce similar detrimental changes, raising the hypothesis that simultaneous exposure could result in even more severe outcomes. Thus, we investigated whether the co-exposure to NIC and the synthetic cannabinoid WIN 55,212-2 (WIN) in adolescent mice causes behavioral outcomes different from those observed after exposure to a single drug. Male Swiss mice were exposed twice daily to NIC, WIN, or NIC + WIN during adolescence (PND28-47) or adulthood (PND70-89). Drug combination led to a greater reduction in weight gain in adolescent mice, while NIC-induced weight loss was observed in adults. During administration, NIC provoked hypothermia, and WIN produced hyperlocomotion in adolescent and adult mice. Animals exposed to NIC + WIN presented a profile of changes similar to those exposed to NIC. After drug exposure, changes in locomotion, thigmotaxis, social preference, prepulse inhibition, and working and recognition memory were evaluated. Adolescent but not adult mice exposed to NIC showed withdrawal-related hyperlocomotion unaffected by WIN co-administration. An age-specific impairment in object recognition memory was induced only by drug co-exposure during adolescence, which resolved spontaneously before reaching early adulthood. A transient decrease in hippocampal α7 nAChR subunit and CB1 receptor mRNA levels was induced by NIC exposure, which may be involved but is not enough to explain the memory impairment. Our work confirms the potential of NIC and cannabinoids association to aggravate some of the individual drug effects during critical neurodevelopmental periods.

Could the Urease of the Gut Bacterium Proteus mirabilis Play a Role in the Altered Gut-Brain Talk Associated with Parkinson's Disease?

Intestinal dysbiosis seems to play a role in neurodegenerative pathologies. Parkinson's disease (PD) patients have an altered gut microbiota. Moreover, mice treated orally with the gut microbe Proteus mirabilis developed Parkinson's-like symptoms. Here, the possible involvement of P. mirabilis urease (PMU) and its B subunit (PmUreß) in the pathogenesis of PD was assessed. Purified proteins were given to mice intraperitoneally (20 µg/animal/day) for one week. Behavioral tests were conducted, and brain homogenates of the treated animals were subjected to immunoassays. After treatment with PMU, the levels of TNF-α and IL-1ß were measured in Caco2 cells and cellular permeability was assayed in Hek 293. The proteins were incubated in vitro with α-synuclein and examined via transmission electron microscopy. Our results showed that PMU treatment induced depressive-like behavior in mice. No motor deficits were observed. The brain homogenates had an increased content of caspase-9, while the levels of α-synuclein and tyrosine hydroxylase decreased. PMU increased the pro-inflammatory cytokines and altered the cellular permeability in cultured cells. The urease, but not the PmUreß, altered the morphology of α-synuclein aggregates in vitro, forming fragmented aggregates. We concluded that PMU promotes pro-inflammatory effects in cultured cells. In vivo, PMU induces neuroinflammation and a depressive-like phenotype compatible with the first stages of PD development.

Different outcomes of neonatal and adult Zika virus infection on startle reflex and prepulse inhibition in mice.

Zika virus (ZIKV) infection causes severe neurological consequences in both gestationally-exposed infants and adults. Sensorial gating deficits strongly correlate to the motor, sensorial and cognitive impairments observed in ZIKV-infected patients. However, no startle response or prepulse inhibition (PPI) assessment has been made in patients or animal models. In this study, we identified different outcomes according to the age of infection and sex in mice: neonatally infected animals presented an increase in PPI and delayed startle latency. However, adult-infected male mice presented lower startle amplitude, while a PPI impairment was observed 14 days after infection in both sexes. Our data further the understanding of the functional impacts of ZIKV on the developing and mature nervous system, which could help explain other behavioral and cognitive alterations caused by the virus. With this study, we support the startle reflex testing in ZIKV-exposed patients, especially infants, allowing for early detection of functional neuromotor damage and early intervention.

Alkylamides from Acmella oleracea: antinociceptive effect and molecular docking with cannabinoid and TRPV1 receptors.

Alkylamides are secondary metabolites in Acmella oleracea and display wide applications in treating several diseases. Since alkylamides can inhibit pain, this work aims to evaluate the antinociceptive profile of A. Oleracea methanolic extracts used in vivo and in silico assays. The extracts inhibited the neurogenic and inflammatory phases of the formalin test, ratifying the antinociceptive effect of alkylamides. Furthermore, the results from molecular docking demonstrated the interaction of A. oleracea alkylamides with the CB1/CB2 and TRPV1 receptors. Additionally, the crude methanolic extract of flowers did not induce potential side effects related to the classical cannabinoid tetrad: hypolocomotion and catalepsy. In conclusion, this work confirms the potential of the alkylamides of A. Oleracea as antinociceptive agents and, for the first time, correlates its effects with the endocannabinoid and vanilloid systems through in silico assays.

Intermittent repeated stress but not ketamine changes mice response to antidepressants.

Discovery of the rapid antidepressant effect of ketamine has been considered one of the most important advances in major depressive disorder treatment. Several studies report a significant benefit to patients that lasts up to 19 days after treatment. However, concerns arise from the long-term use of ketamine, thus a safe and effective strategy for maintaining its antidepressant effect is still necessary. To this end, our work assessed the effects of imipramine and fluoxetine after repeated ketamine treatment in male mice. Ketamine (30 mg/kg/day for 14 days) induced an anti-immobility effect in the forced swimming (FS) paradigm, detected 1 and 3 days after treatment. Seven days after the last ketamine injection, mice received imipramine (20 mg/kg) or fluoxetine (30 mg/kg). Imipramine and fluoxetine did not change mice's immobility time, regardless of the pre-treatment (saline or ketamine). Since both drugs' anti-immobility effect was demonstrated in the classical FS test, we can assume that repeated exposure to intermittent stress inhibited the antidepressant drugs' anti-immobility effects. Moreover, pre-exposure to ketamine did not counteract stress-induced changes in mice response to antidepressants. Since exposure to forced swim and i.p. injections are stressful to rodents, each stressor's contribution to the blunted response to antidepressants was investigated. Our data demonstrated that both stressors (FS and i.p. injections) influenced the reported effect. In summary, our results showed that exposure to intermittent repeated stress inhibited the anti-immobility effect of imipramine and fluoxetine in mice and corroborated findings demonstrating that exposure to stress can blunt patients' response to antidepressants.

Design of new dopamine D2 receptor ligands: biosynthesis and pharmacological evaluation of the hydroxylated metabolite of LASSBio-581.

LASSBio-581 is a N-phenylpiperazine derivative designed for the treatment of schizophrenia. In this study, four strains of filamentous fungi were screened for their capabilities to biotransform LASSBio-581. Cunninghamella echinulata ATCC 9244 was chosen to scale up the biosynthesis of the p-hydroxylated metabolite of LASSBio-581. The chemical structure of the metabolite was confirmed by NMR, LC-MS and X-ray crystallography. Binding studies performed on brain homogenate indicated that the p-hydroxylated metabolite can be considered more selective for dopamine receptors than LASSBio-581, and, therefore, can be used to design new selective dopamine inhibitors.

Searching for multi-target antipsychotics: Discovery of orally active heterocyclic N-phenylpiperazine ligands of D2-like and 5-HT1A receptors.

We described herein the design, synthesis, and pharmacological evaluation of N-phenylpiperazine heterocyclic derivatives as multi-target compounds potentially useful for the treatment of schizophrenia. The isosteric replacement of the heterocyclic ring at the biaryl motif generating pyrazole, 1,2,3-triazole, and 2-methylimidazole[1,2-a]pyridine derivatives resulted in 21 analogues with different substitutions at the para-biaryl and para-phenylpiperazine positions. Among the compounds prepared, 4 (LASSBio-579) and 10 (LASSBio-664) exhibited an adequate binding profile and a potential for schizophrenia positive symptoms treatment without cataleptogenic effects. Structural features of this molecular scaffold are discussed regarding binding affinity and selectivity for D(2)-like, 5-HT(1A), and 5-HT(2A) receptors.

Effects of combined 5-HT2A and cannabinoid receptor modulation on a schizophrenia-related prepulse inhibition deficit in mice.

RATIONALE: Prepulse inhibition of the startle reflex (PPI) is disrupted in several psychiatric disorders including schizophrenia. Understanding PPI pharmacology may help elucidate the pathophysiology of these disorders and lead to better treatments. Given the advantages of multi-target approaches for complex mental illnesses treatment, we have investigated the interaction between receptors known to modulate PPI (5-HT1A and 5-HT2A) and the neuromodulatory endocannabinoid system. OBJECTIVES: To investigate serotonin and cannabinoid receptor (CBR) co-modulation in a model of PPI disruption relevant to schizophrenia METHODS: Male Swiss mice were pretreated with WIN 55,212-2 (CBR agonist), rimonabant (CB1R inverse agonist), 8-OH-DPAT (5-HT1A/7 agonist), and volinanserin (5-HT2A antagonist) or with a combination of a cannabinoid and a serotonergic drug. PPI disruption was induced by acute administration of MK-801. RESULTS: WIN 55,212-2 and rimonabant did not change PPI nor block MK-801-induced deficits. 8-OH-DPAT increased PPI in control mice and, in a higher dose, inhibited MK-801-induced impairments. Volinanserin also increased PPI in control and MK-801-treated mice, presenting an inverted U-shaped dose-response curve. Co-administration of either cannabinoid ligand with 8-OH-DPAT did not change PPI; however, the combination of volinanserin with rimonabant increased PPI in both control and MK-801-exposed mice. CONCLUSIONS: WIN 55,212-2 and rimonabant had similar effects in PPI. Moreover, serotonin and cannabinoid receptors interact to modulate PPI. While co-modulation of CBR and 5-HT1A receptors did not change PPI, a beneficial effect of 5-HT2A and CB1R antagonist combination was detected, possibly mediated through potentiation of 5-HT2A blockade effects by concomitant CB1R blockade.

α7 nicotinic receptor full agonist reverse basolateral amygdala hyperactivity and attenuation of dopaminergic neuron activity in rats exposed to chronic mild stress.

Neuroimaging and preclinical studies showing that nicotinic receptors (nAChR) may play a role in mood control has increased interest in targeting the cholinergic system for treatment of major depressive disorder. Indeed, modulation of nAChRs in the basolateral amygdala (BLA) are sufficient to produce an anti-immobility effect in the mouse tail suspension test. However, how α7 nAChR modulation impacts BLA neuronal activity in vivo as well as the downstream mechanisms involved in its mood-related effects are not understood. In this work, we used the unpredictable chronic mild stress (CMS) model to investigate the mechanisms underlying the antidepressant-like effect of an α7 nAChR full agonist on BLA-induced changes in dopaminergic neurotransmission. Male adult Sprague-Dawley rats were exposed to four weeks of CMS. Behavioral and electrophysiological experiments were performed within one week following stress. CMS exposure increased rats' immobility time in the forced swimming test, decreased the number of spontaneously active dopamine neurons in the ventral tegmental area and increased the firing rate of putative projection neurons in the BLA. Stress-induced behavioral and electrophysiological changes were reversed by a single systemic administration of PNU282987. In summary, our findings corroborate previous descriptions of a potential rapid antidepressant effect for the α7 nAChR full agonist. This effect appears to involve a mechanism distinct from those of classic antidepressants: normalization of BLA hyperactivity and, consequently, of DA hypofunction. These observations corroborate the role of α7 nAChR as a potential target for novel antidepressant drug development.

Zika virus replicates in adult human brain tissue and impairs synapses and memory in mice.

Neurological complications affecting the central nervous system have been reported in adult patients infected by Zika virus (ZIKV) but the underlying mechanisms remain unknown. Here, we report that ZIKV replicates in human and mouse adult brain tissue, targeting mature neurons. ZIKV preferentially targets memory-related brain regions, inhibits hippocampal long-term potentiation and induces memory impairment in adult mice. TNF-α upregulation, microgliosis and upregulation of complement system proteins, C1q and C3, are induced by ZIKV infection. Microglia are found to engulf hippocampal presynaptic terminals during acute infection. Neutralization of TNF-α signaling, blockage of microglial activation or of C1q/C3 prevent synapse and memory impairment in ZIKV-infected mice. Results suggest that ZIKV induces synapse and memory dysfunction via aberrant activation of TNF-α, microglia and complement. Our findings establish a mechanism by which ZIKV affects the adult brain, and point to the need of evaluating cognitive deficits as a potential comorbidity in ZIKV-infected adults.

Serotonergic neurotransmission mediates hypothermia induced by the N-phenylpiperazine antipsychotic prototypes LASSBio-579 and LASSBio-581.

Previous studies have demonstrated that LASSBio-579 and LASSBio-581, two N-phenylpiperazine derivatives designed for the treatment of schizophrenia, are presynaptic dopamine D(2) receptor agonists that induce a hypothermic effect in mice that is not mediated by dopamine receptor activation. The aim of the present study was to investigate possible serotonergic mechanisms underlying hypothermia induced by LASSBio-579 and LASSBio-581 in CF1 mice. The reduction in core temperature was dose-dependent (15-60 mg/kg, i.p.) and occurred by the oral route (30 mg/kg). Pretreatment with haloperidol (4 mg/kg, i.p.) resulted in a synergistic hypothermic effect. Pretreatment with (+/-)DOI (0.25 mg/kg, i.p.), a serotonin 5-HT(2A/C) receptor agonist, reduced the hypothermic effect induced by LASSBio-579 and LASSBio-581 at 15 and 30 mg/kg, i.p. In contrast, (+/-)DOI enhanced the hypothermia induced by both compounds at 60 mg/kg, i.p. The serotonin 5-HT1A antagonist WAY 100635 (0.05 mg/kg, s.c.) abolished the hypothermia induced by LASSBio-579 and diminished the hypothermia induced by LASSBio-581. Pretreatment with LASSBio579 (30 and 60 mg/kg, i.p.) and LASSBio-581 (60 mg/kg, i.p.) reduced the number of head-twitches induced by (+/-)DOI (2.5 mg/kg, i.p.). The ear-scratch response induced by (+/-)DOI was inhibited by both LASSBio-579 and LASSBio-581 at 60 mg/kg, i.p. These results indicate that LASSBio-579 and LASSBio-581 have mechanisms of action through the serotonergic neurotransmitter system.

Pharmacokinetic evaluation of LASSBio-579: an N-phenylpiperazine antipsychotic prototype.

This work aimed to investigate the pharmacokinetics of the N-phenylpiperazine antipsychotic prototype LASSBio-579 and to compare the results with those described for its bioisosteric derivative LASSBio-581. LASSBio-579 was administered to male Wistar rats as a 10 mg kg(-1) intravenous bolus and 30 and 60 mg kg(-1) intraperitoneal and 60 mg kg(-1) oral doses, and plasma concentrations were determined by a validated LC-MS/MS method. Individual plasma concentration-time profiles were evaluated by non-compartmental and compartmental analysis, using WinNonlin. LASSBio-579 plasma protein binding was 93 +/- 4%. After intravenous administration of 10 mg kg(-1), the Vd(ss) (0.6 +/- 0.2 L kg -1) and the t(1/2) (5.2 +/- 1.1 h) determined were smaller than those obtained after extravascular routes, but the CL(tot) (0.23 +/- 0.05 Lh(-1)kg(-1)) was statistically similar (alpha = 0.05). The intraperitoneal and oral bioavailability was around 1.7% and 0.6%, respectively. The plasma profiles obtained after intravenous and intraperitoneal administration of the compound were best fitted to a three-compartment and two-compartment lag-time open model, respectively. Brain tissue showed low penetration (6.3%) and t(1/2) of 1.1 h. Both the limited bioavailability and the lower brain penetration of LASSBio-579, in comparison with the LASSBio-581, suggest that its CNS activity may be due to a high receptor binding affinity or to a specific distribution into brain structures.

α7 Nicotinic receptor-modulating agents reverse the hyperdopaminergic tone in the MAM model of schizophrenia.

Recent evidence has emerged supporting a role for the cholinergic system in schizophrenia, including the potential of α7 modulators as a treatment strategy. However, preclinical studies to date have relied on studies in normal systems rather than on a validated developmental model of schizophrenia. Furthermore, there have been only few studies on whether orthosteric and allosteric modulators have differential impacts in such models. Thus, we investigated the effects of α7 agonists and positive allosteric modulators (PAMs) on dopamine (DA) neuron activity in the ventral tegmental area (VTA) in the methylazoxymethanol acetate (MAM) developmental disruption model of schizophrenia. Four different drugs were evaluated: PNU282987 (full agonist), SSR180711 (partial agonist) NS1738 (PAM type I) and PNU120596 (PAM type II). PNU120596 increased the number of spontaneously active VTA DA neurons in normal rats. In contrast, PNU282987 and SSR180711 reduced the hyperdopaminergic tone in MAM rats. This appeared to be due to effects on DA afferent regulation, in that PNU282987 or SSR180711 infusion into the ventral hippocampus of MAM rats replicated the decrease in the number of spontaneously active VTA DA neurons. In contrast, infusion of the same drugs into the basolateral amygdala increased the number of spontaneously active VTA DA neurons in normal rats without impacting MAM rats. These data suggest that α7 receptors may represent a promising target in the development of new pharmacological therapies for schizophrenia.

Acute and chronic neurological consequences of early-life Zika virus infection in mice.

Although congenital Zika virus (ZIKV) exposure has been associated with microcephaly and other neurodevelopmental disorders, long-term consequences of perinatal infection are largely unknown. We evaluated short- and long-term neuropathological and behavioral consequences of neonatal ZIKV infection in mice. ZIKV showed brain tropism, causing postnatal-onset microcephaly and several behavioral deficits in adulthood. During the acute phase of infection, mice developed frequent seizures, which were reduced by tumor necrosis factor-α (TNF-α) inhibition. During adulthood, ZIKV replication persisted in neonatally infected mice, and the animals showed increased susceptibility to chemically induced seizures, neurodegeneration, and brain calcifications. Altogether, the results show that neonatal ZIKV infection has long-term neuropathological and behavioral complications in mice and suggest that early inhibition of TNF-α-mediated neuroinflammation might be an effective therapeutic strategy to prevent the development of chronic neurological abnormalities.

Design, synthesis and pharmacological evaluation of N-benzyl-piperidinyl-aryl-acylhydrazone derivatives as donepezil hybrids: Discovery of novel multi-target anti-alzheimer prototype drug candidates.

A new series of sixteen multifunctional N-benzyl-piperidine-aryl-acylhydrazones hybrid derivatives was synthesized and evaluated for multi-target activities related to Alzheimer's disease (AD). The molecular hybridization approach was based on the combination, in a single molecule, of the pharmacophoric N-benzyl-piperidine subunit of donepezil, the substituted hydroxy-piperidine fragment of the AChE inhibitor LASSBio-767, and an acylhydrazone linker, a privileged structure present in a number of synthetic aryl- and aryl-acylhydrazone derivatives with significant AChE and anti-inflammatory activities. Among them, compounds 4c, 4d, 4g and 4j presented the best AChE inhibitory activities, but only compounds 4c and 4g exhibited concurrent anti-inflammatory activity in vitro and in vivo, against amyloid beta oligomer (AßO) induced neuroinflammation. Compound 4c also showed the best in vitro and in vivo neuroprotective effects against AßO-induced neurodegeneration. In addition, compound 4c showed a similar binding mode to donepezil in both acetylated and free forms of AChE enzyme in molecular docking studies and did not show relevant toxic effects on in vitro and in vivo assays, with good predicted ADME parameters in silico. Overall, all these results highlighted compound 4c as a promising and innovative multi-target drug prototype candidate for AD treatment.

Flavonoid Hesperidin Induces Synapse Formation and Improves Memory Performance through the Astrocytic TGF-ß1.

Synapse formation and function are critical events for the brain function and cognition. Astrocytes are active participants in the control of synapses during development and adulthood, but the mechanisms underlying astrocyte synaptogenic potential only began to be better understood recently. Currently, new drugs and molecules, including the flavonoids, have been studied as therapeutic alternatives for modulation of cognitive processes in physiological and pathological conditions. However, the cellular targets and mechanisms of actions of flavonoids remain poorly elucidated. In the present study, we investigated the effects of hesperidin on memory and its cellular and molecular targets in vivo and in vitro, by using a short-term protocol of treatment. The novel object recognition test (NOR) was used to evaluate memory performance of mice intraperitoneally treated with hesperidin 30 min before the training and again before the test phase. The direct effects of hesperidin on synapses and astrocytes were also investigated using in vitro approaches. Here, we described hesperidin as a new drug able to improve memory in healthy adult mice by two main mechanisms: directly, by inducing synapse formation and function between hippocampal and cortical neurons; and indirectly, by enhancing the synaptogenic ability of cortical astrocytes mainly due to increased secretion of transforming growth factor beta-1 (TGF-ß1) by these cells. Our data reinforces the known neuroprotective effect of hesperidin and, by the first time, characterizes its synaptogenic action on the central nervous system (CNS), pointing astrocytes and TGF-ß1 signaling as new cellular and molecular targets of hesperidin. Our work provides not only new data regarding flavonoid's actions on the CNS but also shed light on possible new therapeutic alternative based on astrocyte biology.