Effects of Grape Polyphenols on the Life Span and Neuroinflammatory Alterations Related to Neurodegenerative Parkinson Disease-Like Disturbances in Mice.

Functional nutrition is a valuable supplementation to dietary therapy. Functional foods are enriched with biologically active substances. Plant polyphenols attract particular attention due to multiple beneficial properties attributed to their high antioxidant and other biological activities. We assessed the effect of grape polyphenols on the life span of C57BL/6 mice and on behavioral and neuroinflammatory alterations in a transgenic mouse model of Parkinson disease (PD) with overexpression of the A53T-mutant human α-synuclein. C57BL/6 mice were given a dietary supplement containing grape polyphenol concentrate (GPC-1.5 mL/kg/day) with drinking water from the age of 6-8 weeks for life. Transgenic PD mice received GPC beginning at the age of 10 weeks for four months. GPC significantly influenced the cumulative proportion of surviving and substantially augmented the average life span in mice. In the transgenic PD model, the grape polyphenol (GP) diet enhanced memory reconsolidation and diminished memory extinction in a passive avoidance test. Behavioral effects of GP treatment were accompanied by a decrease in α-synuclein accumulation in the frontal cortex and a reduction in the expression of neuroinflammatory markers (IBA1 and CD54) in the frontal cortex and hippocampus. Thus, a GP-rich diet is recommended as promising functional nutrition for aging people and patients with neurodegenerative disorders.

Methylated arginine analogues: their potential role in atherosclerosis and cognition using the poloxamer-407-induced mouse model of dyslipidemia.

An experimental mouse model of dyslipidemia and atherosclerosis was utilized to study the generation of methylarginines in vivo, as well as any potential behavioral changes in mice associated with the production of excess methylarginines. Following 14 weeks of poloxamer 407 treatment, mice developed atherosclerosis and the plasma concentrations of monomethylarginine and asymmetric dimethylarginine were found to be significantly greater than corresponding concentrations in control mice. This finding may have contributed to the development of aortic atherosclerotic lesions in poloxamer-treated mice by interfering with nitric oxide availability and, hence, normal function of vascular endothelium. Poloxamer-407-treated mice also showed a significant decrease in locomotor and exploratory activity, together with signs of emotional stress and anxiety relative to controls. Passive avoidance testing to assess learning and memory provided suggestive evidence that poloxamer-treated mice could potentially be characterized as having undergone a disruption in the process of forgetting about an aversive event, specifically, a foot shock, when compared with control mice. Thus, it is also suggested that the increase in both plasma monomethylarginine and asymmetric dimethylarginine in poloxamer-407-treated mice may somehow influence learning and memory, because endothelial dysfunction caused by reduced nitric oxide availability has been hypothesized to negatively influence cognitive function.

Alimentary Treatment with Trehalose in a Pharmacological Model of Alzheimer's Disease in Mice: Effects of Different Dosages and Treatment Regimens.

In the treatment of experimental neurodegeneration with disaccharide trehalose, various regimens are used, predominantly a 2% solution, drunk for several weeks. We studied the effects of different regimens of dietary trehalose treatment in an amyloid-ß (Aß) 25-35-induced murine model of Alzheimer's disease (AD). Aß-treated mice received 2% trehalose solution daily, 4% trehalose solution daily (continuous mode) or every other day (intermittent mode), to drink for two weeks. We revealed the dose-dependent effects on autophagy activation in the frontal cortex and hippocampus, and the restoration of behavioral disturbances. A continuous intake of 4% trehalose solution caused the greatest activation of autophagy and the complete recovery of step-through latency in the passive avoidance test that corresponds to associative long-term memory and learning. This regimen also produced an anxiolytic effect in the open field. The effects of all the regimens studied were similar in Aß load, neuroinflammatory response, and neuronal density in the frontal cortex and hippocampus. Trehalose successfully restored these parameters to the levels of the control group. Thus, high doses of trehalose had increased efficacy towards cognitive impairment in a model of early AD-like pathology. These findings could be taken into account for translational studies and the development of clinical approaches for AD therapy using trehalose.

Comparative analysis of early neurodegeneration signs in a mouse model of Alzheimer's disease-like pathology induced by two types of the central (Intracerebroventricular vs. Intrahippocampal) administration of Aß25-35 oligomers.

Animal models of Alzheimer's disease (AD) induced by intracerebroventricular (ICV) or intrahippocampal (IH) administration of amyloid-beta (Aß) are widely used in current research. It remains unclear whether these models provide similar outcomes or mimic pathological mechanisms of AD equally. The aim of the work was to compare two models induced by ICV or IH administration of Aß25-35 oligomers to C57BL/6 mice. Parameters characterizing cognitive function (passive avoidance test), protein expression (IBA1, Aß, LC3-II) and expression of genes for neuroinflammation (Aif1, Lcn2, Nrf2), autophagy (Atg8, Becn1, Park2), or markers of neurodegeneration (Cst3, Insr, Vegfa) were analyzed. Сognitive deficits, amyloid accumulation, and neuroinflammatory response in the brain evaluated by the microglial activation were similar in both models. Thus, both ways of Aß administration appear to be equally suitable for modelling AD-like pathology in mice. Our findings strongly support the key role of Aß load and neuroinflammatory response in the hippocampus and frontal cortex for the progression of AD-like pathology and development of cognitive deficits. There were certain minor differences between the models in the mRNA level of genes involved in the processes of neuroinflammation, neurodegeneration, and autophagy. Modulating effects of the central administration of Aß25-35 on the mRNA expression of Aif1, Lcn2, Park2, and Vegfa genes in different brain structures were revealed. The effects occurred to be more pronounced with the ICV method compared with the IH method. These findings give insight into the processes at initial stages of Aß-induced pathology depending on a primary location of Aß oligomers in the brain.

Combined induction of mTOR-dependent and mTOR-independent pathways of autophagy activation as an experimental therapy for Alzheimer's disease-like pathology in a mouse model.

Alzheimer's disease (AD) is associated with amyloid-ß (Aß) accumulation that might be hindered by autophagy. There are two ways to induce autophagy: through mTOR-dependent and mTOR-independent pathways (here, by means of rapamycin and trehalose, respectively). The aim of this study was to evaluate the contribution of these pathways and their combination to the treatment of experimental AD. Mice were injected bilaterally intracerebroventricularly with an Aß fragment (25-35) to set up an AD model. Treatment with rapamycin (10 mg/kg, every other day), trehalose consumption with drinking water (2 mg/mL, ad libitum), or their combination started 2 days after the surgery and lasted for 2 weeks. Open-field, plus-maze, and passive avoidance tests were used for behavioral phenotyping. Neuronal density, Aß accumulation, and the expression of autophagy marker LC3-II and neuroinflammatory marker IBA1 were measured in the frontal cortex and hippocampus. mRNA levels of autophagy genes (Atg8, Becn1, and Park2) were assessed in the hippocampus. Trehalose but not rapamycin caused pronounced prolonged autophagy induction and transcriptional activation of autophagy genes. Both drugs effectively prevented Aß deposition and microglia activation. Autophagy inhibitor 3-methyladenine significantly attenuated autophagy activation and disturbed the effect of the inducers on Aß load. The inducers substantially reversed behavioral and neuronal deficits in Aß-injected mice. In many cases, the best outcomes were achieved with the combined treatment. Thus, trehalose alone or combined autophagy activation by the two inducers may be a promising treatment approach to AD-like neurodegeneration. Some aspects of interaction between mTOR-dependent and mTOR-independent pathways of autophagy are discussed.

Neuroprotective Effects of Ceftriaxone Involve the Reduction of Aß Burden and Neuroinflammatory Response in a Mouse Model of Alzheimer's Disease.

Ceftriaxone (CEF) is a safe and multipotent antimicrobial agent that possesses neuroprotective properties. Earlier, we revealed the restoration of cognitive function in OXYS rats with signs of Alzheimer's disease (AD)-like pathology by CEF along with its modulating the expression of genes related to the system of amyloid beta (Aß) metabolism in the brain. The aim of this study was to determine the effects of CEF on behavior, Aß deposition, and associated neuroinflammation using another model of an early AD-like pathology induced by Aß. Mice were injected bilaterally i.c.v. with Aß fragment 25-35 to produce the AD model, while the CEF treatment (100 mg/kg/day, i.p., 36 days) started the next day after the surgery. The open field test, T-maze, Barnes test, IntelliCage, and passive avoidance test were used for behavioral phenotyping. Neuronal density, amyloid accumulation, and the expression of neuroinflammatory markers were measured in the frontal cortex and hippocampus. CEF exhibited beneficial effects on some cognitive features impaired by Aß neurotoxicity including complete restoration of the fear-induced memory and learning in the passive avoidance test and improved place learning in the IntelliCage. CEF significantly attenuated amyloid deposition and neuroinflammatory response. Thus, CEF could be positioned as a potent multipurpose drug as it simultaneously targets proteostasis network and neuroinflammation, as well as glutamate excitotoxicity, oxidative pathways, and neurotrophic function as reported earlier. Together with previous reports on the positive effects of CEF in AD models, the results confirm the potential of CEF as a promising treatment against cognitive decline from the early stages of AD progression.

Treatment with Autophagy Inducer Trehalose Alleviates Memory and Behavioral Impairments and Neuroinflammatory Brain Processes in db/db Mice.

Autophagy attenuation has been found in neurodegenerative diseases, aging, diabetes mellitus, and atherosclerosis. In experimental models of neurodegenerative diseases, the correction of autophagy in the brain reverses neuronal and behavioral deficits and hence seems to be a promising therapy for neuropathologies. Our aim was to study the effect of an autophagy inducer, trehalose, on brain autophagy and behavior in a genetic model of diabetes with signs of neuronal damage (db/db mice). A 2% trehalose solution was administered as drinking water during 24 days of the experiment. Expressions of markers of autophagy (LC3-II), neuroinflammation (IBA1), redox state (NOS), and neuronal density (NeuN) in the brain were assessed by immunohistochemical analysis. For behavioral phenotyping, the open field, elevated plus-maze, tail suspension, pre-pulse inhibition, and passive avoidance tests were used. Trehalose caused a slight reduction in increased blood glucose concentration, considerable autophagy activation, and a decrease in the neuroinflammatory response in the brain along with improvements of exploration, locomotor activity, anxiety, depressive-like behavior, and fear learning and memory in db/db mice. Trehalose exerted some beneficial peripheral and systemic effects and partially reversed behavioral alterations in db/db mice. Thus, trehalose as an inducer of mTOR-independent autophagy is effective at alleviating neuronal and behavioral disturbances accompanying experimental diabetes.

Evaluating the Effects of Grain of Isogenic Wheat Lines Differing in the Content of Anthocyanins in Mouse Models of Neurodegenerative Disorders.

Functional foods enriched with plant polyphenols and anthocyanins in particular attract special attention due to multiple beneficial bioactive properties of the latter. We evaluated the effects of a grain diet rich in anthocyanins in a mouse model of Alzheimer's disease induced by amyloid-beta (Aß) and a transgenic mouse model of Parkinson's disease (PD) with overexpression of human alpha-synuclein. The mice were kept at a diet that consisted of the wheat grain of near isogenic lines differing in anthocyanin content for five-six months. The anthocyanin-rich diet was safe and possessed positive effects on cognitive function. Anthocyanins prevented deficits in working memory induced by Aß or a long-term grain mono-diet; they partially reversed episodic memory alterations. Both types of grain diets prolonged memory extinction and rescued its facilitation in the PD model. The dynamics of the extinction in the group fed with the anthocyanin-rich wheat was closer to that in a group of wild-type mice given standard chow. The anthocyanin-rich diet reduced alpha-synuclein accumulation and modulated microglial response in the brain of the transgenic mice including the elevated expression of arginase1 that marks M2 microglia. Thus, anthocyanin-rich wheat is suggested as a promising source of functional nutrition at the early stages of neurodegenerative disorders.

The increased density of the habenular neurons, high impulsivity, aggression and resistant fear memory in Disc1-Q31L genetic mouse model of depression.

Mood disorders affect nearly 300 million humans worldwide, and it is a leading cause of death from suicide. In the last decade, the habenula has gained increased attention due to its major role to modulate emotional behavior and related psychopathologies, including depression and bipolar disorder, through the modulation of monoamines' neurotransmission. However, it is still unclear which genetic factors may directly affect the function of the habenula and hence, could contribute to the psychopathological mechanisms of mood disorders. Disrupted-In-Schizophrenia-1 (DISC1) gene is among robust gene-candidates predisposing to major depression, bipolar disorder and schizophrenia in humans. DISC1-Q31L, a well-established genetic mouse model of depression, offers a unique opportunity for translational studies. The current study aimed to probe morphological features of the habenula in the DISC1-Q31L mouse line and detect novel behavioral endophenotypes, including the increased emotionality in mutant females, high aggression in mutant males and deficient extinction of fear memory in DISC1 mutant mice of both sexes. The histological analysis found the increased neural density in the lateral and medial habenula in DISC1-Q31L mice regardless of sex, hence, excluding direct association between the habenular neurons and emotionality in mutant females. Altogether, our findings demonstrated, for the first time, the direct impact of the DISC1 gene on the habenular neurons and affective behavior in the DISC1-Q31L genetic mouse line. These new findings suggest that the combination of the DISC1 genetic analysis together with habenular neuroimaging may improve diagnostics of mood disorder in clinical studies.

Therapeutic activation of autophagy by combined treatment with rapamycin and trehalose in a mouse MPTP-induced model of Parkinson's disease.

The neuroprotective effect of autophagy activation by rapamycin and trehalose was studied in a mouse model of Parkinson's disease (PD) induced by neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Both rapamycin (10 mg/kg/day, 7 days) and trehalose (2% in drinking water, 7 days) increased the expression of LC3-II (a marker of autophagy activation) in the frontal cortex and striatum of normal C57Bl/6J mice, with signs of an additive effect. Autophagy stimulation in the striatum was confirmed by a lysosomal osmotic test. In the model of MPTP-induced PD, the two drugs were applied starting from the 2nd day after subchronic daily MPTP administration (20 mg/kg/day, 4 days). A marked increase in LC3-II expression in the striatum was detected under the action of trehalose and in the S. nigra after combined treatment with rapamycin and trehalose. The drugs had a positive effect for recovery of dopaminergic neurons and neuroprotection after MPTP-induced PD-like injury. The therapeutic effect was proven by active restoration of tyrosine hydroxylase (TH) content in the striatum and S. nigra and by improved cognition measured by the passive avoidance learning task. The results revealed the additive effect of the combined treatment with rapamycin and trehalose on dopaminergic deficits (according to the levels of TH expression in the nigrostriatal system) but not on the behavioral performance in the mouse PD model. Thus, the autophagy activation through different pathways by the combination of rapamycin and trehalose reverses both neuronal dopaminergic and behavioral deficits in vivo and seems to be a promising therapy for PD-like pathology.

Effect of poloxamer 407 administration on the serum lipids profile, anxiety level and protease activity in the heart and liver of mice.

Chronic administration of the poloxamer 407 (P-407), a block copolymer, to elevate serum lipids in mice is a well-established mouse model of hyperlipidemia and atherosclerosis. We tested the hypothesis that the activity of several types of proteases in heart and liver tissue is changed in the early stages of atherosclerosis development. Additionally, we evaluated whether increased serum lipids would induce anxiety in mice, as determined by using a 'plus-maze' test. The mice were administered P-407 by intraperitoneal injection twice a week for one month. P-407 administration to mice resulted in a marked increase in total serum cholesterol, atherogenic non-HDL-cholesterol, and especially in total triglycerides, and it also increased anxiety. Morphological changes observed in P-407-treated mice included contractile type changes in cardiomyocytes and foamy macrophages in liver. A significant increase of cysteine proteases cathepsin B and cathepsin L (at 24 h) and aspartate protease cathepsin D (at both 24 h and 5 days) was determined in heart tissue following P-407 administration. However, no changes were noted in heart matrix metalloproteinase activity. The activity of cysteine and aspartate proteases was significantly increased in liver at both 24 hours and 5 days after P-407 administration. In conclusion, administration of P-407 to mice for one month resulted in increased anxiety, and more importantly, there was an increase in the activity of heart and liver proteases secondary to sustained dyslipidemia. It is suggested that heart and liver cysteine and aspartate proteases may represent potential therapeutic targets in the early stages of atherosclerosis.