Effects of betaine on lipopolysaccharide-induced memory impairment in mice and the involvement of GABA transporter 2

Neuroprotective efficiency of celecoxib vesicular bilosomes for the management of lipopolysaccharide-induced Alzheimer in mice employing 23 full factorial design

The aim of this study was to develop and evaluate bilosomes loaded with Celecoxib (CXB) for the efficient treatment of Alzheimer. The thin-film hydration approach was utilized in the formulation of CXB bilosomes (CXB-BLs). The study used a 23-factorial design to investigate the impact of several formulation variables. Three separate parameters were investigated: bile salt type (X1), medication amount (X2), and lipid-bile salt ratio (X3). The dependent responses included entrapment efficiency (Y1: EE %), particle size (Y2: PS), and zeta potential (Y3: ZP). The formulation factors were statistically optimized using the Design-Expert® program. The vesicles demonstrated remarkable CXB encapsulation efficiency, ranging from 94.16 ± 1.91 to 98.38 ± 0.85%. The vesicle sizes ranged from 241.8 ± 6.74 to 352 ± 2.34 nm. The produced formulations have high negative zeta potential values, indicating strong stability. Transmission electron microscopy (TEM) revealed that the optimized vesicles had a spherical form. CXB release from BLs was biphasic, with the release pattern following Higuchi's model. In vivo studies confirmed the efficiency of CXB-BLs in management of lipopolysaccharide-induced Alzheimer as CXB-BLs ameliorated cognitive dysfunction, decreased acetylcholinesterase (AChE), and inhibited neuro-inflammation and neuro-degeneration through reducing Toll-like receptor (TLR4), and Interleukin-1β (IL-1β) levels. The findings suggested that the created CXB-BLs could be a potential drug delivery strategy for Alzheimer's treatment.

Tannic acid coated nanosuspension for oral delivery of chrysin intended for anti-schizophrenic effect in mice

Chrysin is a flavonoid drug with numerous therapeutic activities. It suffers from low intestinal absorption owing to its hydrophobicity. Therefore, the aim of this study is to exploit the efficient technique of nanosuspension (NSP) to formulate chrysin-NSP coated with tannic acid (TA) to improve the solubility and anti-schizophrenic activity of chrysin. A 23 full factorial design was constructed where the independent factors were type of polymer, surfactant concentration (0.5 or 1 %) and the aqueous phase volume (5 or 15 mL), while the dependent responses were the particle size (PS) of the obtained formulation as well as the % chrysin dissolved after 2 h (Q2h). The optimum formulation (NSP-4) composed of 1 % PEG 400 and 1 % Cremophor RH40 in 15 mL aqueous phase. It achieved a PS and Q2h values of 108.00 nm and 38.77 %, respectively. NSP-4 was then coated with TA (TA-coated NSP-4) for further enhancement of chrysin solubility. TA-coated NSP-4 revealed PS and zeta potential values of 150 ± 14 nm and -32.54 ± 2.45 mV, respectively. After 6 h, chrysin dissolved % were 53.97 and 80.22 for uncoated NSP-4 and TA-coated NSP-4, respectively, compared with only 9.47 for free chrysin. The developed formulations and free chrysin were assessed regarding their effect on schizophrenia induced in mice by cuprizone (CPZ). Treatment with the developed formulations and free chrysin ameliorated demyelination and behavioral deficit induced by CPZ via elevating MBP and PI3K/PKC activities as well as reducing GFAP expression levels. The developed formulations and free chrysin inhibited Galactin-3 and TGF-β expressions and stimulated GST antioxidant enzyme. Furthermore, they maintained the balances in glutamatergic and dopaminergic neurotransmission via modulation on neuregulin-1 and alleviated nuclear pyknosis and degeneration in the neurons. The order of activity was: TA-coated NSP-4 > NSP-4 > free chrysin.

Molecular networking-guided investigation of the secondary metabolome of four Morus species and their in vivo neuroprotective potential for the mitigation of Alzheimer's disease

Alzheimer's Disease (AD) is a fatal age-related neurodegenerative condition with a multifactorial etiology contributing to 70% of dementia globally. The search for a multi-target agent to hit different targets involved in the pathogenesis of AD is crucial. In the present study, the neuroprotective effects of four Morus extracts were assessed in LPS-induced AD in mice. Among the studied species, M. macroura exhibited a profound effect on alleviating the loss of cognitive function, improved the learning ability, restored the acetylcholine esterase (AChE) levels to normal, and significantly reduced the tumor necrosis factor alpha (TNF-α) brain content in LPS-treated mice. To investigate the secondary metabolome of the studied Morus species, ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-HRMS/MS), aided with feature-based molecular networking, was employed. Among the annotated features, aryl benzofurans and prenylated flavonoids were suggested as being responsible for the observed neuroprotective effect. Furthermore, some of the detected metabolites were proposed as new natural products such as moranoline di-O-hexoside (1), isomers of trimethoxy-dihydrochalcone-O-dihexoside (59 & 76), (hydroxy-dimethoxyphenyl)butenone-O-hexoside (82), and O-methylpreglabridin-O-sulphate (105). In conclusion, our findings advocate the potential usage of M. macroura leaves for the management of AD, yet after considering further clinical trials.

Hyperactivation of TRPV4 causes the hippocampal pyroptosis pathway and results in cognitive impairment in LPS-treated mice

Pyroptosis, a newly discovered proinflammatory programmed cell death, is involved in the regulation of cognitive dysfunction, such as Alzheimer's disease. Exploring potential drug targets that prevent pyroptotic procedures might benefit the development of a cure for these diseases. In the present study, we explored whether the transient receptor potential vanilloid 4 (TRPV4) blocker HC067047 and knockdown of TRPV4 in the hippocampus could improve cognitive behavior through the inhibition of pyroptosis in a mouse model developed using systemic administration of lipopolysaccharide (LPS). We found that systemic administration of HC067047 or knockdown of hippocampal TRPV4 prevented the activation of canonical and noncanonical pyroptosis in the hippocampus of LPS-treated mice. Consistent with the inhibition of the hippocampal pyroptosis pathway, a knockdown of hippocampal TRPV4 lowered expression of TNF-α, IL-1β, IL-18, and IL-6. Furthermore, we verified that the main pyroptosis cell type might be a neuron, indicated by reduced neuronal marker expression. Mechanically, we also found that knockdown of hippocampal TRPV4 might inhibit phosphorylation of CamkⅡα which results in NFκb mediated inflammasome reduction in the hippocampus of LPS-treated mice. More interestingly, mice intraperitoneally injected with HC067047 or the hippocampus injected with TRPV4 shRNA showed improved cognitive behavior, as indicated by the enhanced discrimination ratio in the NORT, NOPT, and SNPT. Collectively, we consider that HC067047 might be a small molecular drug that prevents pyroptosis, and TRPV4 could be an effective therapeutic target for preventing pyroptosis-induced cognitive dysfunction.

Nose-to-brain delivery of galantamine loaded nanospray dried polyacrylic acid/taurodeoxycholate mixed matrix as a protective therapy in lipopolysaccharide-induced Alzheimer's in mice model

One of the promising drug delivery approaches is performed by nanosizing the administered drug product using the nanospray drying technique. In this study, a combination of several formulation factors was integrated and exploited to augment the bioavailability of galantamine hydrobromide (GAL) via the intranasal route. Nanosized polymeric particles were fabricated using the mucoadhesive polymer, polyacrylic acid (PAA), and the permeability booster, sodium taurodeoxycholate (TDC). First, a preliminary study was conducted to adjust the nanospray drying conditions. Then, formulations were prepared on the basis of a mixed factorial experimental design and further analyzed using Design Expert® software. Different responses were investigated: particle size, polydispersity index, spray rate, drying efficiency, and percent yield. The optimized formulation was further assessed for physical morphology using the scanning electron microscope, flowability, in vitro drug release, and in vivo brain cell uptake using confocal laser scanning microscopy. The promising formulation (F6), composed of equal ratio of PAA and TDC and 20 mg GAL, exhibited a particle size of 185.55 ± 4.3 nm, polydispersity index of 0.413 ± 0.02, and yield-value of 69.58 ± 5.82 %. It also displayed good flowability, complete drug release within 2 h, and enhanced in vivo fluorescent dye uptake and penetration in brain cells. The efficacy of the optimized formulation was examined using lipopolysaccharide-induced Alzheimer's in mice. Results revealed the advantageous influence of the optimized formulation (F6) through downregulation of NF-κβ, IL-1β and GFAP as well as upregulating TGF-1β in adult mice.

Chrysin-phospholipid complex-based solid dispersion for improved anti-aging and neuroprotective effects in mice

The present study aimed to improve the neuroprotective effect of chrysin (CHR) by combining two formulation techniques, phospholipid (PL) complexation and solid dispersion (SD). CHR-phospholipid complex (CHR-PLC) was prepared through solvent evaporation. The molar ratio CHR/PL (1:3), which exhibited the highest complexation efficiency, was selected for the preparation of CHR-PLC loaded SD (CHR-PLC-SD) with 2-hydroxypropyl β cyclodextrin (2-HPβCD) and polyvinylpyrrolidone 8000. CHR-PLC/2-HPβCD (1:2, w/w) displayed the highest aqueous solubility of CHR (5.86 times more than that of plain CHR). CHR-SD was also prepared using 2-HPβCD for comparison. The in vitro dissolution of CHR-PLC-SD4 revealed an enhancement in the dissolution rate over CHR-PLC (1:3), CHR-SD, and plain CHR by six times. The optimum formulations and plain CHR were evaluated for their neuroprotective effect on brain aging induced by D-galactose in mice. The results demonstrated a behavioral activity elevation, an increase of AMPK, LKB1, and PGC1α brain contents as well as a reduction of AGEs, GFAP, NT-3, TNF-α, and NF-κβ brain contents when compared with those of the D-galactose control group. Thus, the developed formulations stimulated neurogenesis and mitochondrial biogenesis as well as suppressed neuroinflammation and neurodegeneration. The order of activity was as follows: CHR-PLC-SD4 > CHR-PLC (1:3) > CHR-SD > plain CHR.

Neuronally produced betaine acts via a ligand-gated ion channel to control behavioral states

Trimethylglycine, or betaine, is an amino acid derivative found in diverse organisms, from bacteria to plants and animals, with well-established functions as a methyl donor and osmolyte in all cells. In addition, betaine is found in the nervous system, though its function there is not well understood. Here, we show that betaine is synthesized in the nervous system of the nematode worm, Caenorhabditis elegans, where it functions in the control of different behavioral states. Specifically, we find that betaine can be produced in a pair of interneurons, the RIMs, and packed into synaptic vesicles by the vesicular monoamine transporter, CAT-1, expressed in these cells. Mutant animals defective in betaine synthesis are unable to control the switch from local to global foraging, a phenotype that can be rescued by restoring betaine specifically to the RIM neurons. These effects on behavior are mediated by a newly identified betaine-gated chloride channel, LGC-41, which is expressed broadly in the navigation circuit. These results implicate neuronally produced betaine as a neuromodulator in vivo and suggest a potentially similar role for betaine in nervous systems of other animals.

Betaine Ameliorates Depressive-Like Behaviors in Zinc Oxide Nanoparticles Exposed Mice

The aim of the current study was to determine protective effects of betaine on depressive-like behaviors in zinc oxide nanoparticles (ZnO NPs) exposed mice. Forty male mice randomly allocated into four experimental groups. Group 1 kept as control and groups 2-4 received oral administration of betaine (30 mg/kg), ZnO NPs (600 mg/kg), and ZnO NPs (600 mg/kg) 1 h after pre-administration of betaine (30 mg/kg) for 7 days, respectively. Then, forced swimming test (FST), tail suspension test (TST), open field test (OFT), and rotarod tests were done. Furthermore, serum malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), and total antioxidant capacity (TAC) levels were determined. Hippocampal tissue samples were collected for histopathological assessment. According to the results, treatment with ZnO NPs significantly increased immobility time in the FST and TST (P<0.05). Betaine significantly decreased immobility time in the FST and TST (P<0.05). Pretreatment with betaine significantly decreased ZnO NPs-induced alterations in the FST and TST (P<0.05). The duration of staying on the rotarod and the numbers of crossings in the OFT significantly decreased in the mice that received ZnO NPs (P<0.05). These results were significantly improved in betaine+ZnO NPs treated mice as compared to the ZnO NPs group (P<0.05). Treatment with ZnO NPs significantly increased serum MDA level while decreased SOD and GPx compared to the control group (P<0.05). These changes were effectively ameliorated by pretreatment with betaine compared to the ZnO NPs group (P<0.05). No significant effect on serum TAC level was observed in all groups (P˃0.05). Administration of ZnO NPs decreased the thickness of hippocampus and pyramidal neurons in the hippocampal dentate gyrus (DG) and CA1 regions were sparsely arranged. Pretreatment with betaine caused an improvement in the histological features of the hippocampus when compared with ZnO NPs-treated mice. Taken together, these results suggest that betaine has protective role against ZnO NPs-induced toxicity in mice.

Immunomodulatory effect of protocatechuic acid on cyclophosphamide induced brain injury in rat: Modulation of inflammosomes NLRP3 and SIRT1

Modulation of the inflammasome NLRP3 and SIRT1 are new combat strategy for brain injury protection. The inflammasome activates proinflammatory cytokines releasing interleukin-1β and interleukin-18 which in turn affect the toxins release from immune cells. In addition, SIRT1 controls many biological functions, such as immune response and oxidative stress. Protocatechuic has versatile biological activities and possesses antioxidant, anti-inflammatory and neuroprotective effects. So this work aims to study immunomodulatory effect of protocatechuic acid on cyclophosphamide chemotherapy drug-induced brain injury via modulation of inflammosomes NLRP3 and SIRT1. Rats were randomly assigned to four experimental groups. Normal control group was injected with a single i.p injection of saline. Cyclophosphamide group was injected with a single i.p injection of cyclophosphamide (200 mg/kg). Protocatechuic acid groups were orally administered (50 &100 mg/kg) once daily for 10 consecutive days after cyclophosphamide injection. Protocatechuic acid administration exhibited improvements of the cognition function and memory, a reduction in brain contents of MDA, NLRP3, IL-1 β, NF-κB, IKBKB and Galectin 3 and an elevation of GSH and SIRT1 compared to cyclophosphamide group. In addition, protocatechuic acid administration ameliorated the elevation of caspase 3 and iNOS gene expression and alleviated the neuron degeneration caused by cyclophosphamide. In conclusion, the therapeutic action of protocatechuic acid and its cellular and molecular mechanisms are new insights against various human ailments, especially, neuroprotective disease as brain injury induced by cyclophosphamide chemotherapy drug in rats through modulation of inflammosomes NLRP3 and SIRT1.

Gut microbiota dysbiosis: The potential mechanisms by which alcohol disrupts gut and brain functions

Alcohol use disorder (AUD) is a high-risk psychiatric disorder and a key cause of death and disability in individuals. In the development of AUD, there is a connection known as the microbiota-gut-brain axis, where alcohol use disrupts the gut barrier, resulting in changes in intestinal permeability as well as the gut microbiota composition, which in turn impairs brain function and worsens the patient’s mental status and gut activity. Potential mechanisms are explored by which alcohol alters gut and brain function through the effects of the gut microbiota and their metabolites on immune and inflammatory pathways. Alcohol and microbiota dysregulation regulating neurotransmitter release, including DA, 5-HT, and GABA, are also discussed. Thus, based on the above discussion, it is possible to speculate on the gut microbiota as an underlying target for the treatment of diseases associated with alcohol addiction. This review will focus more on how alcohol and gut microbiota affect the structure and function of the gut and brain, specific changes in the composition of the gut microbiota, and some measures to mitigate the changes caused by alcohol exposure. This leads to a potential intervention for alcohol addiction through fecal microbiota transplantation, which could normalize the disruption of gut microbiota after AUD.

Salama AA, Tadros SH, El Gedaily RA. Novel Neuroprotective Potential of Bunchosia armeniaca (Cav.) DC against Lipopolysaccharide Induced Alzheimer’s Disease in Mice

Bunchosia armeniaca (Cav.) DC (Malpighiaceae) is one of the well-known traditionally used remedies worldwide. This study aims to explore the leaves’ metabolome via Quadrupole-Time-of-Flight-Liquid-Chromatography-Mass Spectrometry and to investigate the neuroprotective effect of leaves using lipopolysaccharide (LPS) induced Alzheimer’s disease model. Mice were administered LPS (0.25 mg/kg/day; intraperitoneal) as well as methanolic extract (BME), dichloromethane (BDMF), and butanol (BBF) fractions (each 200 mg/kg/day; oral) for one week. BME and BBF improved behavioral activity on the Y maze test, decreased brain content of inflammatory markers such as nuclear factor kappa B and interleukin 1 beta, and prevented the elevation of cytochrome P450 2E1, and glial fibrillary acidic protein compared to the LPS-administered group. Histopathological examination of several brain parts confirmed the neuroprotective effect of the tested extracts. In addition, BBF exhibited higher activity in all tested in vitro antioxidant and acetylcholinesterase inhibition assays. Metabolic profiling offered tentative identification of 88 metabolites, including mainly flavonoids, phenolic acids, and coumarins. Several detected metabolites, such as quercetin, apigenin, baicalin, vitexin, and resveratrol, had previously known neuroprotective effects. The current study highlighted the possible novel potential of B. armeniaca in preventing memory impairment, possibly through its antioxidant effect and inhibition of acetylcholinesterase, inflammatory and oxidative stress mediators.

High Betaine and Dynamic Increase of Betaine Levels Are Both Associated With Poor Prognosis of Patients With Pulmonary Hypertension

Background and Objective

The association between plasma betaine levels and cardiovascular diseases (CVDs) has been revealed except for pulmonary hypertension (PH). In this study, we aimed to explore the role of betaine in patients with PH.

Methods

Inpatients with PH at Fuwai Hospital were enrolled after excluding relative comorbidities. Each patient received at least one follow-up through a clinical visit, and the fasting blood was obtained both at the first and second hospitalization for betaine detection. The primary endpoint was defined as composite outcome events and the mean duration was 14.3 (6.9, 21.3) months. The associations of betaine and changes of betaine (Δbetaine) with disease severity and prognosis were explored.

Results

Finally, a total of 216 patients with PH were included and the medians for betaine plasma levels in the total patients group, low betaine, and high betaine groups were 49.8 (39.0, 68.3) μM, 39.0 (33.5, 44.7) μM, and 68.1 (57.8, 88.7) μM, respectively. High betaine was associated with poor World Health Organization Functional Class (WHO-FC), increased N-terminal pro-brain natriuretic peptide (NT-proBNP), low tricuspid annular plane systolic excursion (TAPSE), and cardiac output index even after adjusting for confounders. Patients with high betaine were over twice the risk to receive the poor prognosis than those with a low level [hazard ratio (HR) = 2.080, (95% CI: 1.033–4.188)]. Moreover, the decrease of betaine level after further treatment was positively correlated to ΔNT-proBNP indicating Δbetaine might be an effector of disease severity, and dynamic increase of betaine was also associated with poor prognosis in PH.

Conclusion

Betaine was associated with disease severity and might be an effector in PH. Patients with increased levels or with dynamic rise of betaine heralded a poor prognosis.

Anti-inflammatory effect of Ailanthus altissima (Mill.) Swingle leaves in lipopolysaccharide-stimulated astrocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Activated astrocytes are involved in the progression of neurodegenerative diseases. Traditionally, Ailanthus altissima (Mill.) Swingle, widely distributed in East Asia, has been used as a medicine for the treatment of fever, gastric diseases, and inflammation. Although A. altissima has been reported to play an anti-inflammatory role in peripheral tissues or cells, its role in the central nervous system (CNS) remains unclear.

AIM OF THE STUDY

In the present study, we investigated the anti-inflammatory effects and mechanism of action of A. altissima in primary astrocytes stimulated by lipopolysaccharide (LPS).

MATERIALS AND METHODS

A nitrite assay was used to measure nitric oxide (NO) production, and the tetrazolium salt 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay was performed to determine cytotoxicity. The expression levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and mitogen-activated protein kinase (MAPK) were determined with western blotting. Reverse-transcription PCR was used to assess the expression of inflammatory cytokines. The levels of reactive oxygen species were measured using 2,7-dichlorodihydrofluorescein diacetate. Luciferase assay and immunocytochemistry were used for assessing nuclear factor-kappa B (NF-κB) transcription and p65 localization, respectively. Memory and social interaction were analyzed using the Y-maze and three-chamber tests, respectively.

RESULTS

The ethanol extract of A. altissima leaves (AAE) inhibited iNOS and COX-2 expression in LPS-stimulated astrocytes. Moreover, AAE reduced the transcription of various proinflammatory mediators, hindered NF-κB activation, and suppressed extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) activation without p38 activation. Ultra-high performance liquid chromatography with mass spectrometry analysis revealed that AAE comprised ethyl gallate, quercetin, and kaempferol, along with luteolin, which has anti-inflammatory properties, and repressed LPS-induced nitrite levels and the nuclear translocation of p65. Finally, oral administration of AAE attenuated LPS-induced memory and social impairment in mice and repressed LPS-induced ERK and JNK activation in the cortices of mice.

CONCLUSION

AAE could have therapeutic uses in the treatment of neuroinflammatory diseases via suppression of astrocyte activation.

Betaine Ameliorates Brain Damage in a Rat Model of Ischemia/Reperfusion Injury

Brain ischemia and reperfusion (I/R) injury may lead to a poor prognosis for ischemic stroke, which could be alleviated by anti-oxidants with diminished oxidative stress. Betaine is a natural nutrient found in beetroot and seafood to improve cognitive performance in the elderly. The present study investigated whether betaine could protect the brain from I/R injury. Results showed that betaine treatment could reduce H₂O₂-induced cell death in the PC12 cell line. Pretreatment with betaine reduced the brain infarct volume and neuronal apoptosis in a rat I/R injury model induced by two-hour middle cerebral artery occlusion (MCAO). Biochemical analyses indicated that betaine treatment decreased pro-inflammatory cytokine production and reduced oxidative stress after I/R injury. Betaine increased the expression of anti-oxidative enzymes, such as glutathione peroxidase 4 (Gpx4) and superoxide dismutase 1 (Sod1), and anti-oxidative non-enzymatic genes, such as 3-mercaptopyruvate sulfurtransferase (Mpst), methionine sulfoxide reductases b1 (Msrb1), and Msrb2. These data suggest that betaine exerts a neuroprotective effect in I/R injury through enzymatic and non-enzymatic anti-oxidative systems and anti-inflammatory mechanisms.

Betaine prevents and reverses the behavioral deficits and synaptic dysfunction induced by repeated ketamine exposure in mice

As an N-methyl-D-aspartate (NMDA) receptor inhibitor, ketamine has become a popular recreational substance and currently is used to address treatment-resistant depression. Since heavy ketamine use is associated with persisting psychosis, cognitive impairments, and neuronal damage, the safety of ketamine treatment for depression should be concerned. The nutrient supplement betaine has been shown to counteract the acute ketamine-induced psychotomimetic effects and cognitive dysfunction through modulating NMDA receptors. This study aimed to determine whether the adjunctive or subsequent betaine treatment would improve the enduring behavioral disturbances and hippocampal synaptic abnormality induced by repeated ketamine exposure. Mice received ketamine twice daily for 14 days, either combined with betaine co-treatment or subsequent betaine post-treatment for 7 days. Thereafter, three-chamber social approach test, reciprocal social interaction, novel location/object recognition test, forced swimming test, and head-twitch response induced by serotonergic hallucinogen were monitored. Data showed that the enduring behavioral abnormalities after repeated ketamine exposure, including disrupted social behaviors, recognition memory impairments, and increased depression-like and hallucinogen-induced head-twitch responses, were remarkably improved by betaine co-treatment or post-treatment. Consistently, betaine protected and reversed the reduced hippocampal synaptic activity, such as decreases in field excitatory post-synaptic potentiation (fEPSP), long-term potentiation (LTP), and PSD-95 levels, after repeated ketamine treatment. These results demonstrated that both co-treatment and post-treatment with betaine could effectively prevent and reverse the adverse behavioral manifestations and hippocampal synaptic plasticity after repeated ketamine use, suggesting that betaine can be used as a novel adjunct therapy with ketamine for treatment-resistant depression and provide benefits for ketamine use disorders.

Anti-depressant Effect of Betaine Mediates via Nitrergic and Serotoninergic Systems in Ovariectomized Mice

This study aimed to determine the anti-depressant effect of betaine (BT) in ovariectomized mice and its possible interaction with nitrergic and serotoninergic systems. In experiment 1, the mice were divided into control and sham groups, ovariectomy (OVX), OVX+BT (12.5mg/kg), OVX+BT (25 mg/kg), and OVX+BT (50mg/kg) groups. In experiment 2, the mice were assigned into control and sham, OVX, OVX+BT (50mg/kg), OVX+L-NAME (10 mg/kg), as well as OVX+injection of the BT and L-NAME. Experiments 3-5 were similar to experiment 2, except for L-Arginine (50 mg/kg), Fluoxetine (5 mg/kg), and Cyproheptadine (4 mg/kg) that were injected instead of the L-NAME. Subsequently, forced swimming test (FST), tail suspension test (TST), and open field test (OFT) were performed in this study. Moreover, this study determined serum Malondialdehyde (MDA), Superoxide dismutase (SOD), Glutathione peroxidase (GPx), and total antioxidant status levels. According to the findings, OVX increased immobility time, compared to the control group (P<0.05). In addition, BT (50mg/kg) decreased depression-induced immobility time, compared to the OVX group (P<0.05). The co-injection of the BT+L-NAME decreased depression-induced immobility time in TST and FST, followed by an increase in the number of crossing in OFT(P<0.05).Moreover, the co-injection of the BT+L-Arginine significantly diminished the antidepressant activity of BT on immobility time and decreased positive effect of BT on the number of crossing (P<0.05). The co-injection of the BT+Fluoxetine significantly amplified the antidepressant activity of BT on immobility time and number of crossing (P<0.05). Furthermore, the co-injection of the BT+Cyproheptadine decreased antidepressant activity of BT on immobility time and number of crossing (P<0.05). The BT (25 and 50mg/kg) reduced the MDA; however, it elevated SOD and GPx levels in OVX mice (P<0.05). It seems that antidepressant activity of BT mediates via nitrergic and serotoninergic systems in OVX mice.

Transcriptomic Analysis Reveals a Sex-Dimorphic Influence of GAT-2 on Murine Liver Function

Accumulating evidence shows that the γ-amino butyric acid (GABA)ergic system affects the functions of different organs, and liver is one of the most sex-dimorphic organs in animals. However, whether and how the GABAergic system influences liver function in a sex-specific manner at the intrinsic molecular level remains elusive. In this study, firstly, we find that the levels of GABA are significantly increased in the livers of female mice with GABA transporter (GAT)-2 deficiency (KO) whereas it only slightly increased in male GAT-2 KO mice. Apart from the amino acid profiles, the expressions of toll-like receptors (TLRs) also differ in the livers of female and male KO mice. Moreover, RNA-seq results show 2,227 differentially expressed genes (DEGs) in which 1,030 are upregulated whereas 1,197 that are downregulated in the livers of female KO mice. Notably, oxidative phosphorylation, non-alcoholic fatty liver disease, Huntington's disease, and peroxisome proliferator-activated receptor (PPAR) signaling pathways are highly enriched by GAT-2 deficiency, indicating that these pathways probably meditate the effects of GAT-2 on female liver functions, on the other hand, only 1,233 DEGs, including 474 are upregulated and 759 are downregulated in the livers of male KO mice. Interestingly, retinol metabolism, PPAR signaling pathway, and tuberculosis pathways are substantially enriched by GAT-2 deficiency, suggesting that these pathways may be responsible for the effects of GAT-2 on male liver functions. Collectively, our results reveal the sex-dimorphic effects of GAT-2 in guiding liver functions, and we propose that targeting the GABAergic system (e.g., GATs) in a sex-specific manner could provide previously unidentified therapeutic opportunities for liver diseases.

β-Lactolin Reduces Age-Related Inflammation and Cognitive Decline

With the rapid increase in aging populations worldwide, there has been an increase in demand for preventive and therapeutic measures for age-related cognitive decline and dementia. Epidemiological studies show that consumption of dairy products reduces the risk for cognitive decline and dementia in the elderly. We have previously demonstrated in randomized trials that the consumption of β-lactolin, a whey-derived Gly-Thr-Trp-Tyr lactotetrapeptide, improves cognitive function in older adults. Orally administered β-lactolin is delivered to the brain and inhibits monoamine oxidase, resulting in alleviation of memory impairment. However, there is currently no evidence of the effects of long-term β-lactolin intake on aging. Here, we found that the discrimination index in the novel object recognition test for object recognition memory was reduced in mice aged 20 months compared with that in young mice, indicating that age-related cognitive decline was induced in the aged mice; in aged mice fed β-lactolin for 3 months, memory impairment was subsequently alleviated. In aged mice, impairment of light/dark activity cycles was found to be induced, which was subsequently alleviated by β-lactolin consumption. Additionally, the number of activated microglia in the hippocampus and cortex and the production of cytokines (tumor necrosis factor-α, macrophage inflammatory protein-1α, and macrophage chemoattractant protein-1) were increased in aged mice compared with those in young mice but were reduced in aged mice fed β-lactolin. The age-related hippocampal atrophy was improved in aged mice fed β-lactolin. Cytochrome c levels in the hippocampus and cortex were increased in aged mice compared with those in young mice but were also reduced by β-lactolin consumption. These results suggest that β-lactolin consumption prevents neural inflammation and alleviates aging-related cognitive decline.

Cross-Interplay between Osmolytes and mTOR in Alzheimer's Disease Pathogenesis

Alzheimer's disease, categorized by the piling of amyloid-β (Aβ), hyperphosphorylated tau, PHFs, NFTs and mTOR hyperactivity, is a neurodegenerative disorder, affecting people across the globe. Osmolytes are known for osmoprotectants and play a pivotal role in protein folding, function and protein stability, thus, preventing proteins aggregation, and counteracting effects of denaturing solutes on proteins. Osmolytes (viz., sorbitol, inositol, and betaine) perform a pivotal function of maintaining homeostasis during hyperosmotic stress. The selective advantage of utilising osmolytes over inorganic ions by cells is in maintaining cell volume without compromising cell function, which is important for organs such as the brain. Osmolytes have been documented not only as neuroprotectors but they also seem to act as neurodegenerators. Betaine, sucrose and trehalose supplementation has been seen to induce autophagy thereby inhibiting the accumulation of Aβ. In contrast, sucrose has also been associated with mTOR hyperactivity, a hallmark of AD pathology. The neuroprotective action of taurine is revealed when taurine supplementation is seen to inhibit neural damage, apoptosis and oxidative damage. Inositol stereoisomers (viz., scyllo-inositol and myo-inositol) have also been seen to inhibit Aβ production and plaque formation in the brain, inhibiting AD pathogenesis. However, TMAO affects the aging process adversely by deregulating the mTOR signalling pathway and then kindling cognitive dysfunction via degradation of chemical synapses and synaptic plasticity. Thus, it can be concluded that osmolytes may act as a probable therapeutic approach for neurodevelopmental disorders. Here, we have reviewed and focussed upon the impact of osmolytes on mTOR signalling pathway and thereby its role in AD pathogenesis.

Alogliptin Attenuates Lipopolysaccharide-Induced Neuroinflammation in Mice Through Modulation of TLR4/MYD88/NF-κB and miRNA-155/SOCS-1 Signaling Pathways

BACKGROUND

Endotoxin-induced neuroinflammation plays a crucial role in the pathogenesis and progression of various neurodegenerative diseases. A growing body of evidence supports that incretin-acting drugs possess various neuroprotective effects that can improve learning and memory impairments in Alzheimer's disease models. Thus, the present study aimed to investigate whether alogliptin, a dipeptidyl peptidase-4 inhibitor, has neuroprotective effects against lipopolysaccharide (LPS)-induced neuroinflammation and cognitive impairment in mice as well as the potential mechanisms underlying these effects.

METHODS

Mice were treated with alogliptin (20 mg/kg/d; p.o.) for 14 days, starting 1 day prior to intracerebroventricular LPS injection (8 μg/μL in 3 μL).

RESULTS

Alogliptin treatment alleviated LPS-induced cognitive impairment as assessed by Morris water maze and novel object recognition tests. Moreover, alogliptin reversed LPS-induced increases in toll-like receptor 4 and myeloid differentiation primary response 88 protein expression, nuclear factor-κB p65 content, and microRNA-155 gene expression. It also rescued LPS-induced decreases in suppressor of cytokine signaling gene expression, cyclic adenosine monophosphate (cAMP) content, and phosphorylated cAMP response element binding protein expression in the brain.

CONCLUSION

The present study sheds light on the potential neuroprotective effects of alogliptin against intracerebroventricular LPS-induced neuroinflammation and its associated memory impairment via inhibition of toll-like receptor 4/ myeloid differentiation primary response 88/ nuclear factor-κB signaling, modulation of microRNA-155/suppressor of cytokine signaling-1 expression, and enhancement of cAMP/phosphorylated cAMP response element binding protein signaling.

What animal models can tell us about long-term cognitive dysfunction following sepsis: A systematic review

Survivors of sepsis often develop long-term cognitive impairments. This review aimed at exploring the results of the behavioral tools and tests which have been used to evaluate cognitive dysfunction in different animal models of sepsis. Two independent investigators searched for sepsis- and cognition-related keywords. 6323 publications were found, of which 355 were selected based on their title, and 226 of these were chosen based on manuscript review. LPS was used to induce sepsis in 171 studies, while CLP was used in 55 studies. Inhibitory avoidance was the most widely used method for assessing aversive memory, followed by fear conditioning and continuous multi-trial inhibitory avoidance. With regard to non-aversive memory, most studies used the water maze, open-field, object recognition, Y-maze, plus maze, and radial maze tests. Both CLP and LPS models of sepsis were effective in inducing short- and long-term behavioral impairment. Our findings help elucidate the mechanisms involved in the pathophysiology of sepsis-induced cognitive changes, as well as the available methods and tests used to study this in animal models.

Prefrontal cortex miR-874-3p prevents lipopolysaccharide-induced depression-like behavior through inhibition of indoleamine 2,3-dioxygenase 1 expression in mice

Indoleamine 2,3-dioxygenase 1 (IDO1) is the first rate-limiting enzyme that metabolizes tryptophan to the kynurenine pathway. Its activity is highly inducible by pro-inflammatory cytokines and correlates with the severity of major depressive disorder (MDD). MicroRNAs (miRNAs) are involved in gene regulation and the development of neuropsychiatric disorders including MDD. However, the role of miRNAs in targeting IDO1 in the pathophysiology of MDD is still unknown. In this study, we investigated the role of novel miRNAs in the regulation of IDO1 activity and its effect on lipopolysaccharide (LPS)-induced depression-like behavior in mice. LPS up-regulated miR-874-3p concomitantly with increase in IDO1 expression in the prefrontal cortex (PFC), increase in immobility in the forced swimming test as depression-like behavior and decrease in locomotor activity as sickness behavior without motor dysfunction. The miR-874-3p increased in both neuron and microglia after LPS. Its mimic significantly suppressed LPS-induced IDO1 expression in the PFC. Infusion of IDO1 inhibitor (1-methyl-l-tryptophan) and miR-874-3p into PFC prevented an increase in immobility in the forced swimming test, but did not decrease in locomotor activity induced by LPS. These results suggest that miR-874-3p may play an important role in preventing the LPS-induced depression-like behavior through inhibition of IDO1 expression. This may also serve as a novel potential target molecule for the treatment of MDD.

Virgin Coconut Oil-Induced Neuroprotection in Lipopolysaccharide-Challenged Rats is Mediated, in Part, Through Cholinergic, Anti-Oxidative and Anti-Inflammatory Pathways

Neuroinflammation is associated with neuronal cell death and could lead to chronic neurodegeneration. This study investigated the neuroprotective potential of virgin coconut oil (VCO) against lipopolysaccharide (LPS)-induced cytotoxicity of neuroblastoma SK-N-SH cells. The findings were validated using Wistar rats, which were fed with 1-10 g/kg VCO for 31 days, exposed to LPS (0.25 mg/kg) and subjected to the Morris Water Maze Test. Brain homogenate was subjected to biochemical analyses and gene expression studies. α-Tocopherol (α-T; 150 mg/kg) served as the positive control. VCO (100 µg/mL) significantly (p < 0.01) improved SK-N-SH viability (+57%) and inhibited reactive oxygen species (-31%) in the presence of LPS. VCO (especially 10 g/kg) also significantly (p < 0.05) enhanced spatial memory of LPS-challenged rats. Brain homogenate of VCO-fed rats was presented with increased acetylcholine (+33%) and reduced acetylcholinesterase (-43%). The upregulated antioxidants may have reduced neuroinflammation [malondialdehyde (-51%), nitric oxide (-49%), Cox-2 (-64%) and iNos (-63%)] through upregulation of IL-10 (+30%) and downregulation of IL-1β (-65%) and Interferon-γ (-25%). There was also reduced expression of Bace-1 (-77%). VCO-induced neuroprotection, which was comparable to α-T, could be mediated, in part, through inflammatory, cholinergic and amyloidogenic pathways.

Anti-nociceptive and antioxidant activity of betaine on formalin- and writhing tests induced pain in mice

Pain is a physiological response which is mediated via the central and peripheral nervous system. Betaine, is a methyl glycine derivative and a commonly used nutrient supplement. The main purpose of the current paper is to determine the possible anti-nociceptive and antioxidant activity and sedative effect of betaine in mice. Adult male albino mice were divided into two categories, formalin and writhing tests. In the formalin test, mice were injected with betaine (10, 20 and 30 mg/kg) or morphine (5 mg/kg). For co-injections mice received betaine (30 mg/kg) + naloxone (2 mg/kg) or atropine (1 mg/kg), chlorpheniramine (20 mg/kg), flumazenil (5 mg/kg), cimetidine (12.5 mg/kg) and cyproheptadine (4 mg/kg). Then the formalin test was done and paw licking time was determined. In the writhing test, injections were the same but the animals were injected with acetic acid (0.6 %) and the percentage of writhing inhibition was recorded. At the end of the study, blood antioxidant levels were determined. According to the results, betaine reduced the pain response in a dose-dependent manner. Co-administration of the naloxone + betaine or flumazenil + betaine significantly decreased the anti-nociceptive effect of betaine on the licking and biting time of the injected paw and inhibited the number of writhing movements. Betaine decreased malondialdehyde (MDA) and improved superoxide dismutase (SOD) and glutathione peroxidase (GPx) levels in formalin receiving mice. No adverse locomotion and sedation effect were observed in betaine-treated mice. These findings suggest that betaine has anti-nociceptive and antioxidant activity in mice, and its anti-nociceptive role interacts with opioidergic and GABA receptors.

Nrf2 Deficiency Exacerbates Cognitive Impairment and Reactive Microgliosis in a Lipopolysaccharide-Induced Neuroinflammatory Mouse Model

The transcription factor Nrf2 is a central regulator of anti-inflammatory and antioxidant mechanisms that contribute to the development and progression of various neurological disorders. Although the direct and indirect Nrf2 regulatory roles on inflammation have been reviewed in recent years, the in vivo evidence of Nrf2 function on lipopolysaccharide (LPS)-induced cognitive decline and characteristic alterations of reactive microglia and astrocytes remains incomplete. During the 3-5 days after LPS or saline injection, 5-6-month-old wildtype (WT) and Nrf2^-/- C57BL/6 mice were subjected to the novel object recognition task. Immunohistochemistry staining was employed for analyses of brain cells. The Nrf2^-/- mice displayed exacerbated LPS-induced cognition impairment (28.1 ± 9.6% in the discrimination index of the novel object recognition task), enhanced hippocampal reactive microgliosis and astrogliosis, and an increased expression level of the water channel transmembrane protein aquaporin 4 when compared with WT controls. In addition, similar overt effects of Nrf2 deficiency on LPS-induced characteristic alterations of brain cells were observed in the cortex and striatum regions of mice. In summary, this transgenic loss-of-function study provides direct in vivo evidence that highlights the functional importance of Nrf2 activation in regulating LPS-induced cognitive alteration, glial responses, and aquaporin 4 expression. This finding provides a better understanding of the complex nature of Nrf2 signaling and neuroprotection.

Effect of pioglitazone and simvastatin in lipopolysaccharide-induced amyloidogenesis and cognitive impairment in mice: possible role of glutamatergic pathway and oxidative stress

Neuroinflammation and β-amyloid (Aβ) deposition in the brain are well known characteristics of neurodegeneration. Diabetes and hypercholesterolemia are the main risk factors leading to memory loss and cognitive impairment. Recently, it was found that statins and thiazolidinediones have promising anti-inflammatory and neuroprotective effects that could delay neurodegeneration and neuronal loss in diabetic and hypercholesterolemic patients. The aim of the present study was to investigate the protective effect of simvastatin, pioglitazone, and their combination in lipopolysaccharide (LPS)-induced neuroinflammation and amyloidogenesis. Mice were divided into five groups: group 1 received 0.9% saline, group 2 received LPS (0.8 mg/kg in saline), group 3 received LPS (0.8 mgl kg)+simvastatin (5 mg/kg in saline), group 4 received LPS (0.8 mg/kg)+pioglitazone (20 mg/kg in saline), group 5 receiving LPS (0.8 mg/kg)+simvastatin (5 mg/kg)+pioglitazone (20 mg/kg). Y-maze and novel object recognition were used to assess the spatial and nonspatial behavioral changes. Nitric oxide levels and glutamate levels were measured to elucidate the anti-glutamatergic and anti-inflammatory effects of the tested drugs. Immunohistochemistry was performed to detect the presence of Aβ1-42 in the mice brain. LPS impaired memory, and increased Aβ deposition, nitric oxide, and glutamate brain levels. Both drugs produced a significant improvement in all parameters. We conclude that simvastatin and pioglitazone may have a protective effect against cognitive impairment induced by LPS, through targeting the glutamatergic and inflammatory pathways, especially in patients having hypercholesterolemia and diabetes.

Preventive Effects of Tryptophan-Methionine Dipeptide on Neural Inflammation and Alzheimer's Pathology

Preventive approaches for age-related memory decline and dementia have become a high priority in the aging society because of the lack of therapeutic approaches. Recent epidemiological studies have reported that fermented dairy products can help prevent dementia. Previously, we identified tryptophan-tyrosine (WY) and tryptophan-methionine (WM) peptides as the suppressants of activation of the primary microglia and showed that WY peptide consumption suppresses inflammation in the brains of Alzheimer's disease model mice. However, the effects of the WM peptide on inflammation in the brain and Alzheimer's pathology have not been investigated. Here, we evaluated the effect of WM peptide consumption on Alzheimer's disease model (5×FAD) mice. In 5×FAD mice, intake of WM peptide suppressed the production of inflammatory cytokines, activation of microglia, and infiltration of activated microglia around β amyloid (Aβ) depositions. WM peptide intake reduced Aβ deposition in the cortex and hippocampus and then improved the object recognition memory. Taken together with previous reports, the current findings indicate that ingestion of tryptophan-related peptides or food material rich in tryptophan-related peptides, thereby regulating microglial activity, represents a potential preventive approach for cognitive decline and dementia related to inflammation.

Iso-α-acids, Hop-Derived Bitter Components of Beer, Attenuate Age-Related Inflammation and Cognitive Decline

With the aging population rapidly increasing worldwide, preventive measures and treatments for age-related cognitive decline and dementia are of utmost importance. We have previously demonstrated that the consumption of iso-α-acids (IAA), which are hop-derived bitter compounds in beer, prevents the formation of disease pathology in a transgenic mouse model of Alzheimer’s disease (AD). However, the effect of IAA consumption on age-related cognitive decline is unknown. In the present study, we examined the effect of long-term and short-term dietary consumption of IAA, on age-related memory impairments and inflammation in the hippocampus of aged mice. When compared with young mice, aged mice showed impairment in spatial working memory during the Y-maze spontaneous alternation test, impairment in object recognition memory during the novel object recognition test (NORT), a pro-inflammatory hippocampal microglial phenotype with increased CD86 expression and inflammatory cytokine production, increased levels of glutamate and amyloid β_1–42, and decreased levels of dopamine (DA). In aged mice fed IAA for 3 months, the age-related alterations in memory, microglial inflammation, and glutamate, amyloid β_1–42, and DA levels were all significantly attenuated. Additionally, the oral administration of IAA for 7 days in aged mice with memory impairment, also improved spatial and object recognition memory. These results suggest that IAA consumption prevents inflammation in the hippocampus and ameliorates age-related cognitive decline.

Prestimulation of Microglia Through TLR4 Pathway Promotes Interferon Beta Expression in a Rat Model of Alzheimer's Disease

Soluble amyloid beta (Aβ) oligomers are the most common forms of Aβ in the early stage of Alzheimer's disease (AD). They are highly toxic to the neurons but their capability to activate microglia remains controversial. Microglia develop two distinct phenotypes, classic (M1) and alternative (M2). Tuning of microglia to the alternative (anti-inflammatory) state is of major interest in treatment of neuroinflammatory disease. This study aimed to assess tuning the microglia to produce interferon beta (IFN-β) as an anti-inflammatory cytokine through TLR4 pathway in a rat model of AD. Microglial BV-2 cells were treated with 1 μg/ml lipopolysaccharides (LPS), Monophosphoryl lipid A (MPL), or vehicles for 24 h, and then incubated with Aβ oligomer. After 24 h, cell pellets were harvested and TIR-domain-containing adapter-inducing interferon-β (TRIF), interferon regulatory factor 3 (IRF3), and IFN-β levels were measured. The ligands/vehicle were microinjected into the right ventricle of male Wistar rats every 3 days. Two weeks later, an osmotic pump filled with oligomeric Aβ/vehicle was implanted in the left ventricle. After 2 weeks, TRIF, IRF3, and IFN-β levels were measured in the hippocampal tissue. TNF-α and IFN-β levels were assessed in the hippocampus using immunohistochemistry. The oligomeric Aβ did not change TRIF, IRF3, and IFN-β levels in both cell culture and hippocampal tissue. However, pretreatment with LPS or MPL increased the level of these proteins. BV-2 cells morphologically express M1 state in presence of higher dose of Aβ oligomer (10 μM). Pretreatment with LPS or MPL decreased the TNF-α and increased the number of IFN-β positive cells in the hippocampus of Aβ-treated rats. In conclusion, pretreatment with low dose TLR4 agonists could induce microglia to produce neuroprotective cytokines including IFN-β which may be considered as a potential strategy to combat neuronal degeneration in AD.

Gypenosides attenuate lipopolysaccharide-induced neuroinflammation and anxiety-like behaviors in rats

Neuroinflammation is considered a major factor in several neuropsychiatric disorders. Gypenosides (GPS) have pharmacological properties with multiple beneficial effects including antiinflammatory, antioxidative, and protective properties. The present study was performed to examine whether GPS shows anxiolytic-like effects in a model of chronic inflammation induced by injection of lipopolysaccharide (LPS) into the rat hippocampus. The effects of GPS on inflammatory factors in the hippocampus and the downstream mechanisms of these effects were also examined. Introduction of LPS into the lateral ventricle caused inflammatory reactions and anxiety-like symptoms in the rats. Daily treatment with GPS (25, 50, and 100 mg/kg) for 21 consecutive days significantly increased the time spent and number of visits to the open arm in the elevated plus maze test, and significantly increased the number of central zone crossings in the open field test. Moreover, GPS administration significantly reduced the freezing response to contextual fear conditioning, and significantly decreased the levels of proinflammatory mediators, such as interleukin-1β (IL-1β), interleukin-6 (IL-6), and nuclear factor-kappaB (NF-κB), levels in the brain. Furthermore, GPS reduced LPS-induced elevated levels of Toll-like receptor 4 (TLR4) mRNA and inhibition of brain-derived neurotrophic factor (BDNF) mRNA levels. Taken together, these results suggest that GPS may have anxiolytic-like effects and may have novel therapeutic potential for anxiety-like behaviors caused by neuroinflammation. GPS may be useful for developing an agents for the treatment of neuropsychiatric disorders, such as anxiety, due to its antiinflammatory activities and the modulation of NF-κB/iNOS/TLR4/BDNF.

Early minor stimulation of microglial TLR2 and TLR4 receptors attenuates Alzheimer's disease-related cognitive deficit in rats: behavioral, molecular, and electrophysiological evidence

At early stages of Alzheimer's disease (AD), soluble amyloid beta (Aβ) accumulates in brain while microglia are in resting state. Microglia can recognize Aβ long after formation of plaques and release neurotoxic mediators. We examined impact of early minor activation of microglia by Toll-like receptors (TLRs) 2 and 4 agonists on Alzheimer's disease-related disturbed synaptic function and spatial memory in rats. Microglial BV-2 cells were treated by 0.1, 1, and 10 μg/mL of the TLRs ligands lipopolysaccharide, monophosphoryl lipid A (MPL), and Pam3Cys for 24 hours. Culture medium was then changed with media containing 1-μM Aβ. Tumour necrosis factor (TNF)-α and CCL3 levels were measured in the supernatant, 24 hours thereafter. One μg of TLRs ligands which was able to release low level of TNF-α and CCL3, was administered intracerebroventricularly (i.c.v) to adult male rats every 3 days for 24 days. At the half of the treatment period, Aβ1-42 was infused i.c.v (0.075 μg/hour) for 2 weeks. Finally, the following factors were measured: memory performance by Morris water maze, postsynaptic potentials of dentate gyrus following perforant pathway stimulation, hippocampal inflammatory cytokines interleukin 1 (IL-1)β and TNF-α, anti-inflammatory cytokines IL-10 and TGF-1β, microglia marker arginase 1, Aβ deposits, and the receptor involved in Aβ clearance, formyl peptide receptor 2 (FPR2). TLRs ligands caused dose-dependent release of TNF-α and CCL3 by BV-2 cells. Aβ-treated cells did not release TNF-α and CCL3, whereas those pretreated with MPL and Pam3Cys significantly released these cytokines in response to Aβ. Low-dose TLRs ligands improved the disturbance in spatial and working memory; restored the impaired long-term potentiation induced by Aβ; decreased TNF-α, and Aβ deposits; enhanced TGF-1β, IL-10, and arginase 1 in the hippocampus of Aβ-treated rats; and increased polarization of hippocampal microglia to the anti-inflammatory phenotype. The ligands increased formyl peptide receptor 2 in both BV-2 cells and hippocampus/cortex of Aβ-treated rats. Microglia can sense/clear soluble Aβ by early low-dose MPL and Pam3Cys and safeguard synaptic function and memory in rats.

Betaine Attenuates Monocrotaline-Induced Pulmonary Arterial Hypertension in Rats via Inhibiting Inflammatory Response

Background: Pulmonary arterial hypertension (PAH) is characterized by increased pulmonary vascular resistance, leading to right ventricular failure and death. Recent studies have suggested that chronic inflammatory processes are involved in the pathogenesis of PAH. Several studies have demonstrated that betaine possesses outstanding anti-inflammatory effects. However, whether betaine exerts protective effects on PAH by inhibiting inflammatory responses in the lungs needs to be explored. To test our hypothesis, we aimed to investigate the effects of betaine on monocrotaline-induced PAH in rats and attempted to further clarify the possible mechanisms. Methods: PAH was induced by monocrotaline (50 mg/kg) and oral administration of betaine (100, 200, and 400 mg/kg/day). The mean pulmonary arterial pressure, right ventricular systolic pressure, and right ventricle hypertrophy index were used to evaluate the development of PAH. Hematoxylin and eosin staining and Masson staining were performed to measure the extents of vascular remodeling and proliferation in fibrous tissue. Monocyte chemoattractant protein-1 (MCP-1) and endothelin-1 (ET-1) were also detected by immunohistochemical staining. Nuclear factor-κB (NF-κB), tumor necrosis factor alpha (TNF-α), and interleukin-1β (IL-1β) were assessed by Western blot. Results: This study showed that betaine improved the abnormalities in right ventricular systolic pressure, mean pulmonary arterial pressure, right ventricle hypertrophy index, and pulmonary arterial remodeling induced by monocrotaline compared with the PAH group. The levels of MCP-1 and ET-1 also decreased. Western blot indicated that the protein expression levels of NF-κB, TNF-α, and IL-1β significantly decreased (p < 0.01). Conclusion: Our study demonstrated that betaine attenuated PAH through its anti-inflammatory effects. Hence, the present data may offer novel targets and promising pharmacological perspectives for treating monocrotaline-induced PAH.

Comparison of the effect of three licorice varieties on cognitive improvement via an amelioration of neuroinflammation in lipopolysaccharide-induced mice

BACKGROUND/OBJECTIVES

Neuroinflammation plays critical role in neurodegenerative disorders, such as Alzheimer's disease (AD). We investigated the effect of three licorice varieties, Glycyrhiza uralensis, G. glabra, and Shinwongam (SW) on a mouse model of inflammation-induced memory and cognitive deficit.

MATERIALS/METHODS

C57BL/6 mice were injected with lipopolysaccharide (LPS; 2.5 mg/kg, intraperitoneally) and orally administrated G. uralensis, G. glabra, and SW extract (150 mg/kg/day). SW, a new species of licorice in Korea, was combined with G. uralensis and G. glabra. Behavioral tests, including the T-maze, novel object recognition and Morris water maze, were carried out to assess learning and memory. In addition, the expressions of inflammation-related proteins in brain tissue were measured by western blotting.

RESULTS

There was a significant decrease in spatial and objective recognition memory in LPS-induced cognitive impairment group, as measured by the T-maze and novel object recognition test; however, the administration of licorice ameliorated these deficits. In addition, licorice-treated groups exhibited improved learning and memory ability in the Morris water maze. Furthermore, LPS-injected mice had up-regulated pro-inflammatory proteins, such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2, interleukin-6, via activation of toll like receptor 4 (TLR4) and nuclear factor-kappa B (NFκB) pathways in the brain. However, these were attenuated by following administration of the three licorice varieties. Interestingly, the SW-administered group showed greater inhibition of iNOS and TLR4 when compared with the other licorice varieties. Furthermore, there was a significant increase in the expression of brain-derived neurotrophic factor (BDNF) in the brain of LPS-induced cognitively impaired mice that were administered licorice, with the greatest effect following SW treatment.

CONCLUSIONS

The three licorice varieties ameliorated the inflammation-induced cognitive dysfunction by down-regulating inflammatory proteins and up-regulating BDNF. These results suggest that licorice, in particular SW, could be potential therapeutic agents against cognitive impairment.

Betaine in the Brain: Characterization of Betaine Uptake, its Influence on Other Osmolytes and its Potential Role in Neuroprotection from Osmotic Stress

Betaine (N-trimethylglycine), a common osmolyte, has received attention because of the number of clinical reports associating betaine supplementation with improved cognition, neuroprotection and exercise physiology. However, tissue analyses report little accumulation of betaine in brain tissue despite the presence of betaine/GABA transporters (BGT1) at the blood brain barrier and in nervous tissue, calling into question whether betaine influences neuronal function directly or indirectly. Therefore, the focus of this study was to determine what capacity nervous tissue has to accumulate betaine, specifically in the hippocampus, a region of the brain associated with learning and memory and one that is particularly susceptible to damage (e.g., seizure activity). Here we report that hippocampal slices actively accumulate betaine in a time, dose and osmolality dependent manner, resulting in peak intracellular concentrations four times extracellular concentrations within 8 h. Our data also indicate that betaine uptake differentially influences the accumulation of other osmolytes. Under isosmotic conditions, betaine uptake minimally impacted some osmolytes (e.g., glycerylphosphorylcholine and glutamate) while significantly reducing others (taurine, creatine, and myo-inositol). Under osmotic stress (hyperosmotic) conditions, we observed dramatic changes in osmolytes like glycine and glutamine-key players in inhibitory neurotransmission-and little change in osmolytes such as taurine, creatine and myo-inositol when betaine was available. These data suggest that betaine may influence pathways of inhibitory neurotransmitter production/recycling in addition to serving as an osmolyte and metabolic intermediate. In sum, our data provide detailed characterization of betaine uptake in the hippocampus that implicates betaine in the modulation of hippocampal neurophysiology and neuroprotection.

Quantitative Determination of Betaine, Choline, Acetylcholine, and 20-Hydroxyecdysone Simultaneously from Atriplex Species by UHPLC-UV-MS

A simple, rapid, and sensitive UHPLC-UV-MS method was developed for the quantitative determination of betaine (1), choline (2), acetylcholine (3), and 20-hydroxyecdysone (4) from various species of Atriplex. The baseline separation of the four analytes was achieved on a reversed phase C18 column within nine minutes. The mobile phase was composed of 50 mM ammonium formate in 2% methanol-water containing 5 mM sodium dodecyl sulfate (pH = 8.2) and methanol with 0.01% ammonium hydroxide. The analytical method was validated for recovery, precision, limits of detection (LOD), and limits of quantification (LOQ). The developed method was applied for the characterization and quantitation of analytes from plant parts of different Atriplex species, including A. canescens, A. fruticulosa, A. fasciculata, A. semibaccata, and A. lentiformis. Compounds 1–4 were found in a range of 0.53–1.61%, detection under limit of quantification (DUL)-0.74, DUL-0.0038, and 0-0.10% ( w/w, mg in 100 mg plant material), respectively, in test samples. In leaf and fruit of A. canescens, a high content of 1, 2, and 4 were identified. The content of 1, 2, and 4 in A. canescens explains the potential implications of this native US plant for human health and nutrition. The result of this study provides a new method to analyze these phytoconstituents simultaneously in a mixture.

Betaine enhances antidepressant-like, but blocks psychotomimetic effects of ketamine in mice

Ketamine is emerging as a new hope against depression, but ketamine-associated psychotomimetic effects limit its clinical use. An adjunct therapy along with ketamine to alleviate its adverse effects and even potentiate the antidepressant effects might be an alternative strategy. Betaine, a methyl derivative of glycine and a dietary supplement, has been shown to have antidepressant-like effects and to act like a partial agonist at the glycine site of N-methyl-D-aspartate receptors (NMDARs). Accordingly, betaine might have potential to be an adjunct to ketamine treatment for depression. The antidepressant-like effects of ketamine and betaine were evaluated by forced swimming test and novelty suppressed feeding test in mice. Both betaine and ketamine produced antidepressant-like effects. Furthermore, we determined the effects of betaine on ketamine-induced antidepressant-like and psychotomimetic behaviors, motor incoordination, hyperlocomotor activity, and anesthesia. The antidepressant-like responses to betaine combined with ketamine were stronger than their individual effects. In contrast, ketamine-induced impairments in prepulse inhibition, novel object recognition test, social interaction, and rotarod test were remarkably attenuated, whereas ketamine-induced hyperlocomotion and loss of righting reflex were not affected by betaine. These findings revealed that betaine could enhance the antidepressant-like effects, yet block the psychotomimetic effects of ketamine, suggesting that betaine can be considered as an add-on therapy to ketamine for treatment-resistant depression and suitable for the treatment of depressive symptoms in patients with schizophrenia.

Pharmacological validation of in-silico guided novel nootropic potential of Achyranthes aspera L

ETHNOPHARMACOLOGICAL RELEVANCE

Achyranthes aspera (A. aspera) has been used as a brain tonic in folk medicine. Although, ethnic use of medicinal plant has been basis for drug discovery from medicinal plants, but the available in-silico tools can be useful to find novel pharmacological uses of medicinal plants beyond their ethnic use.

AIM OF THE STUDY

To validate in-silico prediction for novel nootropic effect of A. aspera by employing battery of tests in mice.

MATERIAL AND METHODS

Phytoconstituents of A. aspera reported in Dictionary of Natural Product were subjected to in-silico prediction using PASS and Pharmaexpert. The nootropic activity predicted for A. aspera was assessed using radial arm maze, passive shock avoidance and novel object recognition tests in mice. After behavioral evaluation animals were decapitated and their brains were collected and stored for estimation of glutamate levels and acetylcholinesterase activity.

RESULTS

In-silico activity spectrum for majority of A. aspera phytoconstituents exhibited excellent prediction score for nootropic activity of this plant. A. aspera extract treatment significantly improved the learning and memory as evident by decreased working memory errors, reference memory errors and latency time in radial arm maze, step through latency in passive shock avoidance and increased recognition index in novel object recognition were observed, moreover significantly enhanced glutamate levels and reduced acetylcholinesterase activity in hippocampus and cortex were observed as compared to the saline treated group.

CONCLUSION

In-silico and in-vivo results suggest that A. aspera plant may improve the learning and memory by modulating the brain glutamatergic and cholinergic neurotransmission.

RIP1 Inhibition Rescues from LPS-Induced RIP3-Mediated Programmed Cell Death, Distributed Energy Metabolism and Spatial Memory Impairment

Receptor interacting protein 1 (RIP1) has a critical role in initiation of programmed necrosis or necroptosis. RIP1 in a close collaboration with RIP3 not only mediates necroptosis but also is involved in apoptosis and inflammatory signaling. However, the interpretation of the distinct function of RIP1 and RIP3 is complicated. Herein, we demonstrated that RIP1 inhibition in the context of LPS-induced neuroinflammation decreases RIP3 expression. Concomitant administration of Nec-1, specific inhibitor of RIP1, with LPS also attenuated the activating effect of RIP3 on metabolic enzymes, glutamate-ammonia ligase and glutamate dehydrogenase as bioenergetic determinants, in hippocampal and cortical cells. RIP1 inhibition possessed an anti-inflammatory effect and improved the antioxidant capacity against LPS. Interestingly, and opposed to some reports that necroptosis inhibition sensitizes cells to apoptosis, our results showed that RIP1 inhibition attenuates apoptotic cell death in response to LPS. The survival of neuronal function was also confirmed by measuring spontaneous alternations of rats in Y-maze. In conclusion, effects of RIP1 inhibition on RIP3 and cell death provide new approaches to ameliorate neuroinflammation and relative disorders.

Glucagon-like peptide-2-induced memory improvement and anxiolytic effects in mice

We investigated the effectiveness of glucagon-like peptide-2 (GLP-2) on memory impairment in lipopolysaccharide (LPS)-treated mice, and anxiety-like behavior in adrenocorticotropic hormone (ACTH)-treated mice. In the Y-maze test, LPS (10 µg/mouse, i.c.v.) significantly decreased spontaneous alternation, which was prevented by pretreatment with GLP-2 (0.01-0.3 µg/mouse, i.c.v.). The GLP-2 treatment just before the Y-maze test also improved LPS-induced memory impairment. Continuous treatment with GLP-2 (3 µg/mouse, i.c.v.) had no effect on the open-field test in saline-treated or ACTH-treated mice. Chronic ACTH treatment did not cause anxiogenic effects in the elevated plus-maze test. GLP-2 showed weak anxiolytic-like effects in the elevated plus-maze test in ACTH-treated, but not saline-treated mice. Moreover, GLP-2 increased 5-HT, but not 5-HIAA and tryptophan hydroxylase 2 levels in the amygdala of ACTH-treated mice. Pharmacological depletion of 5-HT prevented the anxiolytic effects of GLP-2. These results suggest that GLP-2 protected and improved memory function in LPS-treated mice, and also had anxiolytic effects due to changes in the 5-HT system.

Systemic lipopolysaccharide administration impairs retrieval of context-object discrimination, but not spatial, memory: Evidence for selective disruption of specific hippocampus-dependent memory functions during acute neuroinflammation

Neuroinflammation is implicated in impairments in neuronal function and cognition that arise with aging, trauma, and/or disease. Therefore, understanding the underlying basis of the effect of immune system activation on neural function could lead to therapies for treating cognitive decline. Although neuroinflammation is widely thought to preferentially impair hippocampus-dependent memory, data on the effects of cytokines on cognition are mixed. One possible explanation for these inconsistent results is that cytokines may disrupt specific neural processes underlying some forms of memory but not others. In an earlier study, we tested the effect of systemic administration of bacterial lipopolysaccharide (LPS) on retrieval of hippocampus-dependent context memory and neural circuit function in CA3 and CA1 (Czerniawski and Guzowski, 2014). Paralleling impairment in context discrimination memory, we observed changes in neural circuit function consistent with disrupted pattern separation function. In the current study we tested the hypothesis that acute neuroinflammation selectively disrupts memory retrieval in tasks requiring hippocampal pattern separation processes. Male Sprague-Dawley rats given LPS systemically prior to testing exhibited intact performance in tasks that do not require hippocampal pattern separation processes: novel object recognition and spatial memory in the water maze. By contrast, memory retrieval in a task thought to require hippocampal pattern separation, context-object discrimination, was strongly impaired in LPS-treated rats in the absence of any gross effects on exploratory activity or motivation. These data show that LPS administration does not impair memory retrieval in all hippocampus-dependent tasks, and support the hypothesis that acute neuroinflammation impairs context discrimination memory via disruption of pattern separation processes in hippocampus.

Spermine reverses lipopolysaccharide-induced memory deficit in mice

Background

Lipopolysaccharide (LPS) induces neuroinflammation and memory deficit. Since polyamines improve memory in various cognitive tasks, we hypothesized that spermine administration reverses LPS-induced memory deficits in an object recognition task in mice. The involvement of the polyamine binding site at the N-methyl-D-aspartate (NMDA) receptor and cytokine production in the promnesic effect of spermine were investigated.

Methods

Adult male mice were injected with LPS (250 μg/kg, intraperitoneally) and spermine (0.3 to 1 mg/kg, intraperitoneally) or ifenprodil (0.3 to 10 mg/kg, intraperitoneally), or both, and their memory function was evaluated using a novel object recognition task. In addition, cortical and hippocampal cytokines levels were measured by ELISA four hours after LPS injection.

Results

Spermine increased but ifenprodil decreased the recognition index in the novel object recognition task. Spermine, at doses that did not alter memory (0.3 mg/kg, intraperitoneally), reversed the cognitive impairment induced by LPS. Ifenprodil (0.3 mg/kg, intraperitoneally) reversed the protective effect of spermine against LPS-induced memory deficits. However, spermine failed to reverse the LPS-induced increase of cortical and hippocampal cytokine levels.

Conclusions

Spermine protects against LPS-induced memory deficits in mice by a mechanism that involves GluN2B receptors.

Chemobrain: a critical review and causal hypothesis of link between cytokines and epigenetic reprogramming associated with chemotherapy

One consequence of modern cancer therapy is chemotherapy related cognitive dysfunction or "chemobrain", the subjective experience of cognitive deficits at any point during or following chemotherapy. Chemobrain, a well-established clinical syndrome, has become an increasing concern because the number of long-term cancer survivors is growing dramatically. There is strong evidence that correlates changes in peripheral cytokines with the development of chemobrain in commonly used chemotherapeutic drugs for different types of cancer. However, the mechanisms by which these cytokines elicit change in the central nervous system are still unclear. In this review, we hypothesize that the administration of chemotherapy agents initiates a cascade of biological changes, with short-lived alterations in the cytokine milieu inducing persistent epigenetic alterations. These epigenetic changes lead to changes in gene expression, alterations in metabolic activity and neuronal transmission that are responsible for generating the subjective experience of cognition. This speculative but testable hypothesis should help to gain a comprehensive understanding of the mechanism underlying cognitive dysfunction in cancer patients. Such knowledge is critical to identify pharmaceutical targets with the potential to prevent and treat cancer-treatment related cognitive dysfunction and similar disorders.