Neuroprotective Effect of Nanodiamond in Alzheimer's Disease Rat Model: a Pivotal Role for Modulating NF-κB and STAT3 Signaling

Comparing levetiracetam and zonisamide effects on rivastigmine anti-Alzheimer's activity in aluminum chloride-induced Alzheimer's-like disease in rats: Impact on α7 nicotinic acetylcholine receptors and amyloid β

BACKGROUND AND AIM

Alzheimer's disease (AD) is the most progressive form of neurodegenerative disease, which severely impairs cognitive function. The leading class of drugs used to treat AD is acetylcholinesterase inhibitors (AChE-Is) as Rivastigmine (RIVA), partially ameliorate its cognitive symptoms. Since epilepsy is a common comorbidity with AD, we explored the potential that new the antiepileptic drugs; Levetiracetam (LEV) and Zonisamide (ZNS) may possess an additional therapeutic benefit to RIVA in AlCl3-induced AD rat model.

MATERIALS AND METHODS

AlCl3 was used to provoke AD in rats which were then supplemented with treatment drugs for 2 weeks. Treated groups were: Control, AlCl3, RIVA, LEV, RIVA + LEV, ZNS and RIVA + ZNS. Then, the behavioral tests; passive avoidance (PA), Morris water maze (MWM) and novel object recognition (NOR) were conducted to assess cognitive behavior and memory. The Hippocampal Aβ assembly was thoroughly examined by histopathology and ELISA. α7 Nicotinic ACh receptors' (α7nAChRs) expression was assessed immunohistochemically and by real-time quantitative polymerase chain reaction (qPCR). Caspase 3 expression was also assessed by real-time qPCR in hippocampal tissues.

RESULTS

AlCl3 administration impaired memory and cognitive functions in rats, augmented hippocampal Aβ deposition, with subsequent neurodegeneration and α7nAChRs down-regulation. LEV, but not ZNS, administration significantly mitigated AlCl3-induced cognitive impairment probably through suppression of amyloid β (Aβ) deposition, enhancement of neurogenesis and α7nAChRs expression. When combined to RIVA, ZNS treatment negatively affected cognition possibly through its impact on hippocampal Aβ and subsequent neuronal damage.

CONCLUSION

Although our results indicated that neither LEV nor ZNS provided any extra benefit to cognitive enhancements in AD rats receiving rivastigmine, LEV demonstrated positive effects individually while ZNS had negative effects when combined with RIVA. As a result, this study suggests the use of LEV rather than ZNS for managing epilepsy in patients with AD given that Alzheimer's and epilepsy can coexist.

Impaired Resting-State Functional Connectivity in Cerebral Autosomal-Dominant Arteriopathy, Subcortical Infarcts, and Leukoencephalopathy Mutant Mice

BACKGROUND

Cerebral autosomal-dominant arteriopathy, subcortical infarcts, and leukoencephalopathy is the most prevalent monogenic inherited cause of cerebral small vessel disease. Despite its prevalence, there is currently no proven therapy to prevent or reverse the progression of the disease.

METHODS

This study aimed to characterize the functional integrity of long white matter tracts in cerebral autosomal-dominant arteriopathy, subcortical infarcts, and leukoencephalopathy transgenic mice expressing R169C mutant Notch3 (Notch3R169C) compared with wild type littermates (Notch3WT), both with and without a superimposed focal white matter lesion in the corpus callosum, utilizing optical resting-state functional connectivity imaging alongside behavioral examinations. In addition, we examined the efficacy of tocotrienol, a neuroprotective derivative of vitamin E derived from palm oil, which has shown promise in preventing white matter disease progression in clinical trials involving patients with small vessel disease.

RESULTS

At baseline, resting-state interhemispheric and intrahemispheric functional connectivity was significantly lower in Notch3R169C than in Notch3WT (P=0.004), and the grid walk test revealed a higher number of foot faults in the Notch3R169C group compared with Notch3WT. Sex did not interact with the genotype on the primary outcomes. Introducing a lesion in the corpus callosum compromised functional connectivity and behavior outcomes in both genotypes to a similar extent; lesion volumes did not differ between the genotypes. Tocotrienol treatment did not show any protective effect on any end point.

CONCLUSIONS

These data show impaired resting-state functional connectivity and increased foot faults in the Notch3R169C mutant model of cerebral autosomal-dominant arteriopathy, subcortical infarcts, and leukoencephalopathy. Future work will aim to test therapeutic or preventive interventions in cerebral autosomal-dominant arteriopathy, subcortical infarcts, and leukoencephalopathy mutants using these measures.

Eugenol attenuates aluminium-induced neurotoxicity in rats by inhibiting the activation of STAT3 and NF-кB

Aluminium is a common metallic toxicant that easily penetrates the brain and exerts severe pathological effects e.g., oxidative stress, inflammation and neurodegeneration. Eugenol is a natural phenolic compound possessing numerous therapeutic properties including antioxidant, anti-inflammatory and neuroprotective. The compound has also been reported to interfere with important transcription factors like STAT3 and NF-кB. Thus, the present study intended to explore the therapeutic potential of eugenol in aluminium neurotoxicity. Rats were administered AlCl3 (100 mg/kg b. wt., orally) and eugenol (200 mg/kg b. wt., orally) alone or in combination for 45 days. The results revealed that AlCl3 administration increases acetylcholinesterase (AChE) activity, lipid peroxidation (LPO), and protein oxidation (PO) along with decreasing superoxide dismutase (SOD) and catalase (CAT) activities, and glutathione (GSH) content in the cortex and hippocampus regions of the brain. Moreover, AlCl3 induces neuronal loss and astroglial activation in both brain areas. The study further revealed that AlCl3 also increases the expression of transcription factors STAT3 and NF-кB in neurons and astrocytes of the cortex and hippocampus. However, co-administration of eugenol with AlCl3 restored the enzymatic activities of AChE, SOD and CAT, and GSH content, and rescued the cortex and hippocampus from LPO, PO, neuronal loss and astroglial activation. Furthermore, the study reported that eugenol reverses the expression pattern of STAT3 and NF-кB in AlCl3-intoxicated rats. In conclusion, the study suggests that eugenol ameliorates oxidative stress, neuronal loss and reactive astrogliosis in aluminium-induced neurotoxicity by inhibiting signalling molecules, STAT3 and NF-кB.

Interleukin-6 deficiency reduces neuroinflammation by inhibiting the STAT3-cGAS-STING pathway in Alzheimer's disease mice

BACKGROUND

The Interleukin-6 (IL-6)-signal transducer and activator of transcription 3 (STAT3) pathway, along with the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway, are critical contributors to neuroinflammation in Alzheimer's disease (AD). Although previous research outside the context of AD has indicated that the IL-6-STAT3 pathway may regulate the cGAS-STING pathway, the exact molecular mechanisms through which IL-6-STAT3 influences cGAS-STING in AD are still not well understood.

METHODS

The activation of the IL-6-STAT3 and cGAS-STING pathways in the hippocampus of 5×FAD and WT mice was analyzed using WB and qRT-PCR. To explore the effects of IL-6 deficiency, Il6+/- mice were crossed with 5×FAD mice, and the subsequent impact on hippocampal STAT3 pathway activity, cGAS-STING pathway activation, amyloid pathology, neuroinflammation, and cognitive function was evaluated through WB, qRT-PCR, immunohistochemistry, ThS staining, ELISA, and behavioral tests. The regulatory role of STAT3 in the transcription of the Cgas and Sting genes was further validated using ChIP-seq and ChIP-qPCR on hippocampal tissue from 5×FAD and Il6-/-: 5×FAD mice. Additionally, in the BV2 microglial cell line, the impact of STAT3 activation on the transcriptional regulation of Cgas and Sting genes, as well as the production of inflammatory mediators, was examined through WB and qRT-PCR.

RESULTS

We observed marked activation of the IL-6-STAT3 and cGAS-STING pathways in the hippocampus of AD mice, which was attenuated in the absence of IL-6. IL-6 deficiency reduced beta-amyloid deposition and neuroinflammation in the hippocampus of AD mice, contributing to cognitive improvements. Further analysis revealed that STAT3 directly regulates the transcription of both the Cgas and Sting genes. These findings suggest a potential mechanism involving the STAT3-cGAS-STING pathway, wherein IL-6 deficiency mitigates neuroinflammation in AD mice by modulating this pathway.

CONCLUSION

These findings indicate that the STAT3-cGAS-STING pathway is critical in mediating neuroinflammation associated with AD and may represent a potential therapeutic target for modulating this inflammatory process in AD.

Effects of arsenic exposure on the PI3K/Akt/NF-κB signaling pathway in the hippocampus of offspring mice at different developmental stages

The primary purpose of present study was to explore the effects of arsenic exposure on the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/nuclear transcription factor-κB (NF-κB) signaling pathway in the hippocampus of offspring mice at different developmental stages. Sodium arsenite (NaAsO2) at doses of 0, 15, 30 or 60 mg/L administered to female mice and their pups. The nuclear translocation levels of NF-κB were assessed by EMSA. Real-time RT-PCR was used to measure Akt, NF-κB and PI3K mRNA levels. Protein expressions of PI3K, p-Akt, inhibitor kappa B kinase (IKK), p-NF-κB, protein kinase A (PKA), inhibitor kappa B (IκB), and cAMP response element-binding protein (CREB) were measured by Western blot. Results disclosed that exposure to 60 mg/L NaAsO2 could suppress NF-κB levels of nuclear translocation of postnatal day (PND) 20 and PND 40 mice. Arsenic downregulated the transcriptional and translational levels of PI3K, Akt and NF-κB. Additionally, protein expressions of p-IKK, p-IκB, PKA and p-CREB also reduced. Taken together, results of present study indicated that arsenic could downregulate the PI3K/Akt/NF-κB signaling pathway, particularly on PND 40, which might be involved in the cognitive impairments.

Development of nanomedicines for the treatment of Alzheimer's disease: Raison d'être, strategies, challenges and regulatory aspects

Alzheimer's disease (AD) is a chronic neurodegenerative disorder characterized by progressive loss of memory. Presently, AD is challenging to treat with current drug therapy as their delivery to the brain is restricted by the presence of the blood-brain barrier. Nanomedicines, due to their size, high surface volume ratio, and ease of tailoring drug release characteristics, showed their potential to treat AD. The nanotechnology-based formulations for brain targeting are expected to enter the market in the near future. So, regulatory frameworks are required to ensure the quality, safety, and effectiveness of the nanomedicines to treat AD. In this review, we discuss different strategies, in-vitro blood-brain permeation models, in-vivo permeation assessment, and regulatory aspects for the development of nanomedicine to treat AD.

Exploring the neuropharmacological potential of empagliflozin on nootropic and scopolamine-induced amnesic model of Alzheimer's like conditions in rats

BACKGROUND

Alzheimer's disease (AD) is one of the most challenging and prevalent neurodegenerative disorder globally with a rising prevalence, characterized by progressive cognitive decline, memory loss, and behavioural changes. Current research aims to determine the nootropic and anti-amnesic effect of Empagliflozin (EMPA) against scopolamine-induced amnesia in rats, by modulating the cholinergic and N-Methyl D-Aspartate (NMDA) receptors.

METHODS

Rats were treated once daily with an EMPA (5 and 10 mg/kg) and donepezil (2.5 mg/kg) for successive 26 days. During the final 13 days of treatment, a daily injection of scopolamine (1 mg/kg) was administered to induce cognitive deficits.

RESULTS

EMPA was found to be significantly reduce escape latency, increase time spent in the target quadrant, and enhanced the number of target zone crossings in the Morris water maze (MWM) test, indicating improved spatial memory. Moreover, EMPA increased the recognition index and the number of spontaneous alternations in the novel object recognition (NOR) and Y-maze tests, respectively, suggesting enhanced memory.

DISCUSSION

Interestingly doses of EMPA (5 mg/kg, 10 mg/kg) exhibited memory-enhancing effects even in the absence of scopolamine-induced impairment. Biochemical analysis revealed that EMPA elevated the levels of glutathione (GSH), a potent antioxidant, while decreasing lipid peroxidation (LPO) activity and increasing catalase (CAT) levels, indicating its antioxidative properties. Interestingly molecular docking studies revealed that EMPA fit perfectly in the active sites of M1 muscarinic acetylcholine (mACh) and NMDA receptors. These results indicated that the nootropic and antiamnesic effect of EMPA is possibly mediated via M1 and NMDA receptors and might be a remedy for AD.

Diamond-Like Carbon Depositing on the Surface of Polylactide Membrane for Prevention of Adhesion Formation During Tendon Repair

Post-traumatic peritendinous adhesion presents a significant challenge in clinical medicine. This study proposes the use of diamond-like carbon (DLC) deposited on polylactic acid (PLA) membranes as a biophysical mechanism for anti-adhesion barrier to encase ruptured tendons in tendon-injured rats. The results indicate that PLA/DLC composite membrane exhibits more efficient anti-adhesion effect than PLA membrane, with histological score decreasing from 3.12 ± 0.27 to 2.20 ± 0.22 and anti-adhesion effectiveness increasing from 21.61% to 44.72%. Mechanistically, the abundant C=O bond functional groups on the surface of DLC can reduce reactive oxygen species level effectively; thus, the phosphorylation of NF-κB and M1 polarization of macrophages are inhibited. Consequently, excessive inflammatory response augmented by M1 macrophage-originated cytokines including interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) is largely reduced. For biocompatibility evaluation, PLA/DLC membrane is slowly absorbed within tissue and displays prolonged barrier effects compared to traditional PLA membranes. Further studies show the DLC depositing decelerates the release of degradation product lactic acid and its induction of macrophage M2 polarization by interfering esterase and PLA ester bonds, which further delays the fibrosis process. It was found that the PLA/DLC membrane possess an efficient biophysical mechanism for treatment of peritendinous adhesion.

Omaveloxolone ameliorates cognitive dysfunction in APP/PS1 mice by stabilizing the STAT3 pathway

AIMS

To determine the availability and the potential molecular mechanisms underlying the therapeutic effect of omaveloxolone (RTA408) on Alzheimer's Disease (AD).

MATERIALS AND METHODS

This study employed network pharmacology to assess the feasibility of drug treatment of AD. To determine the cognitive status and emotional state of APPswe/PS1dE9 (APP/PS1) mice after the RTA408 treatment, three classical behavioral experiments (water maze, Y-maze, and open field test) were conducted. Immunofluorescence and immunohistochemical staining were utilized to evaluate hippocampal neuronal status and amyloid (Aβ) deposition in mice. RNA-seq and transcription factor prediction analyses were performed to explore the potential molecular mechanisms regulating the therapeutic effects of RTA408. Molecular docking was employed to predict the direct drug targets. To validate these molecular mechanisms, quantitative reverse transcription PCR (qRT-PCR), Western blotting, and immunofluorescence analyses were performed in two instrumental cell lines, i.e., mouse hippocampal neuronal cells (HT22) and microglia (BV2).

RESULTS

RTA408 was revealed with the capability to reduce Aβ plaque deposition and to restore damaged neurons in the hippocampal region of APP/PS1 mice, ultimately leading to an improvement in cognitive function. This beneficial effect was achieved by balancing the STAT3 pathway. Specifically, RTA408 facilitated the activations of both STAT3/OXR1 and NRF2/ARE axes, thereby enhancing the compromised resistance in neurons to oxidative stress. RTA408 inhibited the NFκB/IL6/STAT3 pathway, effectively countering the neuroinflammation triggered by microglial activation.

CONCLUSION

RTA408 is revealed with promising potential in the treatment of AD based on preclinical data.

Linking Cognitive Impairment with Amyloid-β Accumulation in Alzheimer's Disease: Insights from Behavioral Tests and FTIR Spectroscopy

Background

Alzheimer's disease (AD) is a neurodegenerative disorder that progresses over time. Fourier Transform Infrared Spectroscopy (FTIR) analysis gives identification of the main metabolic changes that happen during neurodegeneration, by monitoring biochemical and molecular structure alterations that can help in AD diagnosis or treatment approach.

Objective

The aim of the present work is to assess AD hallmarks in molecular structure of retina and monitor accumulation of amyloid beta42(Aβ42) in brain and retina during disease progression.

Methods

AD induced in rats by Aluminum Chloride (AlCl3). Retinal molecular structure during disease progression for 2,4,6 and 8 weeks was assessed by Fourier-transform infrared spectroscopy (FTIR) and the incidence of the disease was confirmed by a behavioural assessment; the Morris Water Maze test. Aβ42 levels in the brain and retina were also measured.

Results

The results indicated that cognitive impairment starting from 6 weeks of AlCl3 administration. Retinal concentration of Aβ42 was significant increase (p < 0.05) from 2 weeks that precedes the observed increase of Aβ42 in the brain which appeared after 4 weeks of AlCl3 administration. Multivariate principal component analysis discovers that the variance noticed in the infrared spectra due to AD condition and it is time dependent for progression of the disease.

Conclusions

The accumulation of Aβ42 is a sensitive early biomarker in retina for AD. FTIR analysis of the retina revealed changes in hydrogen bond formation or destruction, alterations in lipid chain length and branching accompanied by depleted lipid content and carbonization, as well as degeneration of the retinal tissue due to AD.

n-3 Polyunsaturated Fatty Acids Modulate LPS-Induced ARDS and the Lung-Brain Axis of Communication in Wild-Type versus Fat-1 Mice Genetically Modified for Leukotriene B4 Receptor 1 or Chemerin Receptor 23 Knockout

Specialized pro-resolving mediators (SPMs) and especially Resolvin E1 (RvE1) can actively terminate inflammation and promote healing during lung diseases such as acute respiratory distress syndrome (ARDS). Although ARDS primarily affects the lung, many ARDS patients also develop neurocognitive impairments. To investigate the connection between the lung and brain during ARDS and the therapeutic potential of SPMs and its derivatives, fat-1 mice were crossbred with RvE1 receptor knockout mice. ARDS was induced in these mice by intratracheal application of lipopolysaccharide (LPS, 10 µg). Mice were sacrificed at 0 h, 4 h, 24 h, 72 h, and 120 h post inflammation, and effects on the lung, liver, and brain were assessed by RT-PCR, multiplex, immunohistochemistry, Western blot, and LC-MS/MS. Protein and mRNA analyses of the lung, liver, and hypothalamus revealed LPS-induced lung inflammation increased inflammatory signaling in the hypothalamus despite low signaling in the periphery. Neutrophil recruitment in different brain structures was determined by immunohistochemical staining. Overall, we showed that immune cell trafficking to the brain contributed to immune-to-brain communication during ARDS rather than cytokines. Deficiency in RvE1 receptors and enhanced omega-3 polyunsaturated fatty acid levels (fat-1 mice) affect lung-brain interaction during ARDS by altering profiles of several inflammatory and lipid mediators and glial activity markers.

Anxiolytic effects of Chrysanthemum morifolium Ramat Carbonisata-based carbon dots in mCPP-induced anxiety-like behavior in mice: a nature-inspired approach

Introduction: Anxiety disorders have emerged as a predominant health concern, yet existing pharmacological treatments for anxiety still present various challenges. Chrysanthemum morifolium Ramat Carbonisata (CMRC) has been utilized in China for approximately 400 years as a therapeutic intervention for anxiety disorders. In this study, a novel type of carbon dots derived from the decoction of Chrysanthemum morifolium Ramat Carbonisata (CMRC-CDs) was identified and isolated, and their morphological structure and functional groups were characterized. Furthermore, the effects of CMRC-CDs on m-chlorophenylpiperazine (mCPP)-induced anxiety-like behaviour in mice were examined and quantified. In order to investigate the potential mechanisms of their anxiolytic effects, concentrations of hypothalamic-pituitary-adrenal (HPA) axis hormones, amino acid neurotransmitters, and monoamine neurotransmitters were measured. Methods: In this study, we synthesized CMRC-CDs and evaluated their potential anti-anxiety effects in a controlled experiment involving 48 male ICR mice. The mice were randomly divided into six groups, treated with CMRC-CDs at different doses for 14 days, and subjected to Open-Field (OF) and Elevated Plus Maze (EPM) tests. Post-behavioral evaluations, blood samples and brain tissues were collected for neurotransmitter and Hypothalamic-Pituitary-Adrenal (HPA) axis hormone quantification via ELISA. Additionally, cytotoxicity of CMRC-CDs was assessed using a Cell Counting Kit-8 (CCK-8) assay on RAW 264.7 cells. Results and Discussion: CMRC-CDs were spherical and homogeneously dispersed, with diameters ranging from 1.4 to 4.0 nm and an abundance of chemical groups on their surface. In the open-field (OF) test, mice pre-treated with CMRC-CDs demonstrated an increased proportion of time spent in the central area and a higher frequency of entries into the central area. In the elevated plus maze (EPM) test, mice pre-treated with CMRC-CDs exhibited a greater number of entries into the open arm and an extended duration spent in the open arm. CMRC-CDs were observed to decrease serum concentrations of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and corticosterone (CORT). Furthermore, CMRC-CDs were found to increase γ-aminobutyric acid (GABA) and 5-hydroxytryptamine (5-HT) levels, while concurrently reducing glutamic acid (Glu) concentrations in brain tissue. CMRC-CDs demonstrated anxiolytic effects, which may be attributed to their modulation of hormones and neurotransmitters. This finding suggests the potential therapeutic value of CMRC-CDs in the clinical treatment of anxiety disorders.

A systematic study on the use of multifunctional nanodiamonds for neuritogenesis and super-resolution imaging

BACKGROUND

Regeneration of defective neurons in central nervous system is a highlighted issue for neurodegenerative disease treatment. Various tissue engineering approaches have focused on neuritogenesis to achieve the regeneration of damaged neuronal cells because damaged neurons often fail to achieve spontaneous restoration of neonatal neurites. Meanwhile, owing to the demand for a better diagnosis, studies of super-resolution imaging techniques in fluorescence microscopy have triggered the technological development to surpass the classical resolution dictated by the optical diffraction limit for precise observations of neuronal behaviors. Herein, the multifunctional nanodiamonds (NDs) as neuritogenesis promoters and super-resolution imaging probes were studied.

METHODS

To investigate the neuritogenesis-inducing capability of NDs, ND-containing growing medium and differentiation medium were added to the HT-22 hippocampal neuronal cells and incubated for 10 d. In vitro and ex vivo images were visualized through custom-built two-photon microscopy using NDs as imaging probes and the direct stochastic optical reconstruction microscopy (dSTORM) process was performed for the super-resolution reconstruction owing to the photoblinking properties of NDs. Moreover, ex vivo imaging of the mouse brain was performed 24 h after the intravenous injection of NDs.

RESULTS

NDs were endocytosed by the cells and promoted spontaneous neuritogenesis without any differentiation factors, where NDs exhibited no significant toxicity with their outstanding biocompatibility. The images of ND-endocytosed cells were reconstructed into super-resolution images through dSTORM, thereby addressing the problem of image distortion due to nano-sized particles, including size expansion and the challenge in distinguishing the nearby located particles. Furthermore, the ex vivo images of NDs in mouse brain confirmed that NDs could penetrate the blood-brain barrier (BBB) and retain their photoblinking property for dSTORM application.

CONCLUSIONS

It was demonstrated that the NDs are capable of dSTORM super-resolution imaging, neuritogenic facilitation, and BBB penetration, suggesting their remarkable potential in biological applications.

[Recent research on cytokines associated with anti-N-methyl-D-aspartate receptor encephalitis]

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is an autoimmune inflammatory disease of the central nervous system, and little is known about its immune mechanism at present. There is a lack of disease-related biomarkers in cerebrospinal fluid except anti-NMDAR antibody, which leads to delayed diagnosis and treatment in some patients. Therefore, there has been an increasing number of studies on related cytokines in recent years to assess whether they can be used as new biomarkers for evaluating disease conditions and assisting diagnosis and treatment. Current studies have shown that some cytokines may be associated with the progression of anti-NMDAR encephalitis, and this article reviews the research advances in such cytokines associated with anti-NMDAR encephalitis.

Neuroprotective efficacy of the bacterial metabolite, prodigiosin, against aluminium chloride-induced neurochemical alternations associated with Alzheimer's disease murine model: Involvement of Nrf2/HO-1/NF-κB signaling

Prodigiosin (PDG) is a bacterial metabolite with numerous biological and pharmaceutical properties. Exposure to aluminium is considered a root etiological factor in the pathological progress of Alzheimer's disease (AD). Here, in this investigation, we explored the neuroprotective potential of PDG against aluminium chloride (AlCl₃ )-mediated AD-like neurological alterations in rats. For this purpose, rats were gavaged either AlCl₃ (100 mg/kg), PDG (300 mg/kg), or both for 42 days. As a result of the analyzes performed on the hippocampal tissue, it was observed that AlCl₃ induced biochemical, molecular, and histopathological changes like those related to AD. PDG pre-treatment significantly decreased acetylcholinesterase activity and restored the levels of brain-derived neurotrophic factor, monoamines (dopamine, norepinephrine, and serotonin), and transmembrane protein (Na⁺ /K⁺ -ATPase). Furthermore, PDG boosted the hippocampal antioxidant capacity, as shown by the increased superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glutathione contents. These findings were accompanied by decreases in malondialdehyde and nitric oxide levels. The antioxidant effect may promote the upregulation of the expression of antioxidant genes (Nrf2 and HO-1). Moreover, PDG exerted notable anti-inflammatory effects via the lessening of interleukin-1 beta, tumor necrosis factor-alpha, cyclooxygenase-2, nuclear factor kappa B, and decreases in the gene expression of inducible nitric oxide synthase. In addition, noteworthy decreases in pro-apoptotic (Bax and caspase-3) levels and increases in anti-apoptotic (Bcl-2) biomarkers suggested an anti-apoptotic effect of PDG. In support, the hippocampal histological examination validated the aforementioned changes. To summarize, the promising neuromodulatory, antioxidative, anti-inflammatory, and anti-apoptotic activities of PDG establish it as a potent therapeutic option for AD.

Maternal High Fat Diet Anticipates the AD-like Phenotype in 3xTg-AD Mice by Epigenetic Dysregulation of Aβ Metabolism

Maternal overnutrition has been reported to affect brain plasticity of the offspring by altering gene expression, regulating both synaptic plasticity and adult neurogenesis. However, whether perinatal metabolic stress may influence the accumulation of misfolded proteins and the development of neurodegeneration remains to be clarified. We investigated the impact of maternal high fat diet (HFD) in an experimental model of Alzheimer's disease (AD). The 3xTg-AD mice born to overfed mothers showed an impairment of synaptic plasticity and cognitive deficits earlier than controls. Maternal HFD also altered the expression of genes regulating amyloid-β-protein (Aβ) metabolism (i.e., Bace1, Ern1, Ide and Nicastrin) and enhanced Aβ deposition in the hippocampus. Finally, we found an epigenetic derangement and an aberrant recruitment of transcription factors NF-kB and STAT3 and chromatin remodeler HDAC2 on the regulatory sequences of the same genes. Collectively, our data indicate that early life metabolic stress worsens the AD phenotype via epigenetic alteration of genes regulating Aβ synthesis and clearance.

Evolution of Detecting Early Onset of Alzheimer's Disease: From Neuroimaging to Optical Immunoassays

Alzheimer's disease (AD) is a pathological disorder defined by the symptoms of memory loss and deterioration of cognitive abilities over time. Although the etiology is complex, it is mainly associated with the accumulation of toxic amyloid-β peptide (Aβ) aggregates and tau protein-induced neurofibrillary tangles (NFTs). Even now, creating non-invasive, sensitive, specific, and cost-effective diagnostic methods for AD remains challenging. Over the past few decades, polymers, and nanomaterials (e.g., nanodiamonds, nanogold, quantum dots) have become attractive and practical tools in nanomedicine for diagnosis and treatment. This review focuses on current developments in sensing methods such as enzyme-linked immunosorbent assay (ELISA) and surface-enhanced Raman scattering (SERS) to boost the sensitivity in detecting related biomarkers for AD. In addition, optical analysis platforms such as ELISA and SERS have found increasing popularity among researchers due to their excellent sensitivity and specificity, which may go as low as the femtomolar range. While ELISA offers easy technological usage and high throughput, SERS has the advantages of improved mobility, simple electrical equipment integration, and lower cost. Both portable optical sensing techniques are highly superior in terms of sensitivity, specificity, human application, and practicality, enabling the early identification of AD biomarkers.

Interlacing the relevance of caspase activation in the onset and progression of Alzheimer's disease

Caspases, a family of cysteine proteases is a renowned regulator of apoptosis. Members of this family are responsible for the proteolytic dismantling of numerous cellular structures. Apart from apoptosis, caspases remarkably contribute to a diverse range of molecular processes. Being the imperative members of several cellular cascades their abnormal activation/deactivation has severe implications and also leads to various diseased conditions. Similar aberrant activation of caspases is one of the several causes of neuropathologies associated with Alzheimer's disease (AD), a form of dementia severely affecting neuropsychiatric and cognitive functions. Emerging studies are providing deeper insights into the mechanisms of caspase action in the progression of AD. Current article is an attempt to review these studies and present the action mechanisms of different mammalian caspases in the advancement of AD associated neuropathologies.

Role of pro-inflammatory cytokines in Alzheimer's disease and neuroprotective effects of pegylated self-assembled nanoscaffolds

Neurodegeneration and synaptic loss in Alzheimer's disease (AD) lead to impairment in memory functions. Neuroinflammation causes activation of microglia and astrocytes cells that locally and systemically produces inflammatory cytokines which can serve as early diagnostic markers or therapeutic targets in AD. Pro-inflammatory cytokines (Interleukins (IL-1β, IL-6 and IL-10) and tumor necrosis factor (TNF α)) levels were estimated in serum, cerebral tissue, hepatic tissue, and renal tissue in treatment groups of scopolamine-induced amnesia mice model using ELISA protocol. The results showed that cerebral tissue of AD mice exhibited elevated levels of IL1β, IL6, IL10 and TNFα which indicate contribution of pro-inflammatory cytokines in the progression of AD. A significant reduction in the concentration of IL1β, IL-10 and TNF-α were noticed in serum, cerebral tissue and hepatic tissue of animal group treated with marketed memantine tablet (Admenta), pure memantine drug (MEMp), memantine-poly (lactic-co-glycolic acid) self-assembled nanoscaffolds (MEM-PLGA) SANs, Polyethylene Glycol coated memantine-poly (lactic-co-glycolic acid) self-assembled nanoscaffolds [(PEG-MEM-PLGA) SANs] and Polyethylene Glycol coated memantine-poly [(lactic-co-glycolic acid)] self-assembled nanoscaffolds grafted with Bone Marrow Derived Stem Cell ((PEG-MEM-PLGA) SANs-BMSc), whereas a high level of IL-6 was observed in hepatic tissue, cerebral tissue and renal tissues of normal and AD induced mice which showed the emerging potential of IL-6 cytokines that can trigger either neurons survival after injury or causing neurodegeneration and cell apoptosis. The Neuroregenerative potential of stem cells helps in the proliferation of neuronal cell and thus improves cognition in AD animal model.

Exploring the potential anti-Alzheimer disease mechanisms of Alpiniae Oxyphyliae Fructus by network pharmacology study and molecular docking

Alpiniae Oxyphyliae Fructus (AOF) (yizhi) is a frequently medicated Chinese herb for Alzheimer disease (AD) treatment. The present study investigated the components and potential mechanisms of AOF through network pharmacology analysis and molecular docking. The results showed that AOF contains at least 20 active ingredients and involves 184 target genes. A total of 301 AD-related genes were obtained from the DisGeNET, GeneCards, GEO, OMIM, and Alzheimer Disease: Genes databases. A total of 41 key targets were identified from the topology analysis of the AOF-AD target network. These key targets are involved in 105 signal pathways, such as the PI3K-Akt, HIF-1, and MAPK pathways, and can regulate gene transcription, cell death, cell proliferation, drug response, and protein phosphorylation. AOF's active ingredients, Chrysin, Isocyperol, Izalpinin, Linolenic acid, CHEMBL489541, Oxyphyllenone A, Oxyphyllenone B, and Oxyphyllol C, show high affinity to targets, including PPARG, ESR1, and AKT1. These findings provide a new basis for AOF application and anti-AD study.

Carbon Dots Derived from Os Draconis and Their Anxiolytic Effect

Background

At present, people are susceptible to developing depression and anxiety disorders in response to stress. However, there is no specific medicine for anxiety. Os Draconis (OD, named "Long gu" in Chinese) are fossilized bones that have been used in traditional Chinese medicine to treat neurological diseases for thousands of years. Thus, we conducted this study to determine the biological basis for the anxiolytic effect of OD.

Methods

In this study, novel carbon dots (OD-CDs) from OD decoctions were discovered and separated. OD-CDs were anatomized using nanomaterials characterization methods to characterize the morphological structure, optical properties, and functional group properties. Four behavioural tests were conducted to observe the behavioural activities of mice, including the open field test (OFT), light/dark box test (LDT), elevated plus maze test (EPMT), and novelty-suppressed feeding test (NSFT), to determine its anxiolytic effects. Moreover, we assessed the possible mechanisms of the OD-CDs by detecting hormones associated with the hypothalamic-pituitary-adrenal (HPA) axis.

Results

OD-CDs were spherical and monodispersed with a narrow size distribution between 1 and 5 nm and had a yield of 3.67%. OD-CDs increased the activity time of mice in the central zone in the OFT. The mice in the experimental group showed more frequent activity in the light compartment and the open arms, in LDT and EPMT, respectively. In addition, OD-CDs shortened the feeding latency in the NSFT. Furthermore, the results after OD-CDs intervention showed a significant increase in serum serotonin (5-HT) and norepinephrine (NE). In addition, the concentrations of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ATCH), and corticosterone (CORT) were decreased.

Conclusion

These results demonstrate a definite anxiolytic effect of OD-CDs and reveal the possible mechanism of action of OD-CDs' anxiolytic effect, which supports the research of OD for neurological disorders and a promising new trend of therapeutic approach and drug development.

Inflammation and Autophagy: A Convergent Point between Autism Spectrum Disorder (ASD)-Related Genetic and Environmental Factors: Focus on Aluminum Adjuvants

Autism spectrum disorder (ASD), schizophrenia, and bipolar disorder are genetically complex and heterogeneous neurodevelopmental disorders (NDDs) resulting from genetic factors and gene-environment (GxE) interactions for which onset occurs in early brain development. Recent progress highlights the link between ASD and (i) immunogenetics, neurodevelopment, and inflammation, and (ii) impairments of autophagy, a crucial neurodevelopmental process involved in synaptic pruning. Among various environmental factors causing risk for ASD, aluminum (Al)-containing vaccines injected during critical periods have received special attention and triggered relevant scientific questions. The aim of this review is to discuss the current knowledge on the role of early inflammation, immune and autophagy dysfunction in ASD as well as preclinical studies which question Al adjuvant impacts on brain and immune maturation. We highlight the most recent breakthroughs and the lack of epidemiological, pharmacokinetic and pharmacodynamic data constituting a "scientific gap". We propose additional research, such as genetic studies that could contribute to identify populations at genetic risk, improving diagnosis, and potentially the development of new therapeutic tools.

Recent Synergy of Nanodiamonds: Role in Brain-Targeted Drug Delivery for the Management of Neurological Disorders

The aim of the present review article is to summarize the role of nanodiamonds in various neurological diseases. We have taken related literature of making this review article from ScienceDirect, springer, Research gate, PubMed, Sci-finder, etc. The current approaches for treating neurological conditions such as glioblastoma includes chemotherapy or combination anti-retro viral therapy for HIV (human immunodeficiency virus) or use of anti-Alzheimer drugs during cognitive impairment. These approaches can provide only symptomatic relief as they do not target the cause of the disease due to their inability to penetrate the blood brain barrier. On long-term use, they may cause CNS toxicity due to accumulation in the brain. So nanodiamonds could prove as a promising approach in the brain targeting of the bioactive and to treat many neurological disorders such as Alzheimer's disease, Parkinson's disease, brain tumor (glioblastoma), HIV, amyotrophic multiple sclerosis, Huntington disease, stroke (cerebrovascular attack), batten disease, schizophrenia, epilepsy, and bacterial infections (encephalitis, sepsis, and meningitis) due to their ability to penetrate the blood-brain barrier and owing to their excellent surface properties, i.e., nano size and high surface area, ease of functionalization, multiple drug binding, and biocompatibility; they can be useful for brain targeted drug delivery with minimal side effects.

Nanodiamonds as Possible Tools for Improved Management of Bladder Cancer and Bacterial Cystitis

Nanodiamonds (NDs) are a class of carbon nanomaterials with sizes ranging from a few nm to micrometres. Due to their excellent physical, chemical and optical properties, they have recently attracted much attention in biomedicine. In addition, their exceptional biocompatibility and the possibility of precise surface functionalisation offer promising opportunities for biological applications such as cell labelling and imaging, as well as targeted drug delivery. However, using NDs for selective targeting of desired biomolecules within a complex biological system remains challenging. Urinary bladder cancer and bacterial cystitis are major diseases of the bladder with high incidence and poor treatment options. In this review, we present: (i) the synthesis, properties and functionalisation of NDs; (ii) recent advances in the study of various NDs used for better treatment of bladder cancer and (iii) bacterial cystitis; and (iv) the use of NDs in theranostics of these diseases.

Nanoparticle Effects on Stress Response Pathways and Nanoparticle-Protein Interactions

Nanoparticles (NPs) are increasingly used in a wide variety of applications and products; however, NPs may affect stress response pathways and interact with proteins in biological systems. This review article will provide an overview of the beneficial and detrimental effects of NPs on stress response pathways with a focus on NP-protein interactions. Depending upon the particular NP, experimental model system, and dose and exposure conditions, the introduction of NPs may have either positive or negative effects. Cellular processes such as the development of oxidative stress, the initiation of the inflammatory response, mitochondrial function, detoxification, and alterations to signaling pathways are all affected by the introduction of NPs. In terms of tissue-specific effects, the local microenvironment can have a profound effect on whether an NP is beneficial or harmful to cells. Interactions of NPs with metal-binding proteins (zinc, copper, iron and calcium) affect both their structure and function. This review will provide insights into the current knowledge of protein-based nanotoxicology and closely examines the targets of specific NPs.

Phosphodiesterase (PDE) III inhibitor, Cilostazol, improved memory impairment in aluminum chloride-treated rats: modulation of cAMP/CREB pathway

The most prevalent type of dementia is Alzheimer's disease (AD), which is currently incurable. Existing treatments for Alzheimer's disease, such as acetylcholinesterase inhibitors, are only effective for symptom relief. Disease-modifying medications for Alzheimer's disease are desperately required, given the enormous burdens that the disease places on individuals and communities. Phosphodiesterase (PDE) inhibitors are gaining a lot of attention in the research community because of their potential in treating age-related cognitive decline. Cilostazol is a selective PDE III inhibitor used as antiplatelet agent through cAMP response element-binding (CREB) protein phosphorylation pathway (cAMP/CREB). The neuroprotective effect of cilostazol in AD-like cognitive decline in rats was investigated in this study. After 2 months of intraperitoneal administration of 10 mg/kg aluminum chloride, Morris water maze and Y-maze (behavioral tests) were performed. After that, histological and biochemical examinations of the hippocampal region were carried out. Aluminum chloride-treated rats showed histological, biochemical, and behavioral changes similar to Alzheimer's disease. Cilostazol improved rats' behavioral and histological conditions, raised neprilysin level while reduced levels of amyloid-beta protein and phosphorylated tau protein. It also decreased the hippocampal levels of tumor necrosis factor-alpha, nuclear factor-kappa B, FAS ligand, acetylcholinesterase content, and malondialdehyde. These outcomes demonstrate the protective activity of cilostazol versus aluminum-induced memory impairment.

Improvement of synaptic plasticity by nanoparticles and the related mechanisms: Applications and prospects

Synaptic plasticity is an important basis of learning and memory and participates in brain network remodelling after different types of brain injury (such as that caused by neurodegenerative diseases, cerebral ischaemic injury, posttraumatic stress disorder (PTSD), and psychiatric disorders). Therefore, improving synaptic plasticity is particularly important for the treatment of nervous system-related diseases. With the rapid development of nanotechnology, increasing evidence has shown that nanoparticles (NPs) can cross the blood-brain barrier (BBB) in different ways, directly or indirectly act on nerve cells, regulate synaptic plasticity, and ultimately improve nerve function. Therefore, to better elucidate the effect of NPs on synaptic plasticity, we review evidence showing that NPs can improve synaptic plasticity by regulating different influencing factors, such as neurotransmitters, receptors, presynaptic membrane proteins and postsynaptic membrane proteins, and further discuss the possible mechanism by which NPs improve synaptic plasticity. We conclude that NPs can improve synaptic plasticity and restore the function of damaged nerves by inhibiting neuroinflammation and oxidative stress, inducing autophagy, and regulating ion channels on the cell membrane. By reviewing the mechanism by which NPs regulate synaptic plasticity and the applications of NPs for the treatment of neurological diseases, we also propose directions for future research in this field and provide an important reference for follow-up research.

Improved cognition impairment by activating cannabinoid receptor type 2: Modulating CREB/BDNF expression and impeding TLR-4/NFκBp65/M1 microglia signaling pathway in D-galactose-injected ovariectomized rats

Alzheimer's disease (AD) is characterized by an active inflammatory response induced by the brain's deposition and accumulation of amyloid-beta (Aβ). Cannabinoid receptor type 2 (CB2R) is expressed in specific brain areas, modulating functions, and pathophysiologies in CNS. Herein, we aimed to evaluate whether activation of CB2R can improve the cognitive impairment in the experimental AD-like model and determine the involved intracellular signaling pathway. Injection of D-galactose (150 mg/kg, i.p.) was performed to urge AD-like features in bilaterally ovariectomized female rats (OVC/D-gal rats) for 8-weeks. Then, AM1241, a CB2R-agonist (3 and 6 mg/kg), was injected intraperitoneally starting from the 6th week. Treatment with AM1241, significantly down-regulated; Toll-like receptor4 (TLR4), Myd88 (TLR4-adaptor protein) genes expression, and the pro-inflammatory cytokines (NFκB p65, TNF-α, IL-6, and IL-12). In contrast, it enhanced BDNF (the brain-derived neurotrophic factor) and CREB (the cyclic AMP response element-binding protein) as well as the immune-modulatory cytokines (IL-4 and IL-10) levels. Moreover, AM1241 lessened the immune-expression of GFAP, CD68, caspase-3, and NFκB p65 markers and mended the histopathological damage observed in OVC/D-gal rats by decreasing the deposition of amyloid plaques and degenerative neuronal lesions, as well as improving their recognition and learning memory in both novel object recognition and Morris water maze tests. In conclusion, activating CB2R by the selective agonist AM1241 can overrun cognitive deficits in OVC/D-gal rats through modulation of TLR4/ NFκB p65 signaling, mediated by modulating CREB/BDNF pathway, thereby can be applied as a potential therapeutic strategy in AD treatment.

Fluorescence Imaging, Metabolism, and Biodistribution of Biocompatible Carbon Dots Synthesized Using Punica granatum L. Peel

In this study, a green, low-cost strategy is reported for the synthesis of carbon dots (CDs) using Punica granatum L. A systematic metabolic analysis and determination of the biodistribution of the nitrogen-doped carbon dots was conducted in vivo in mice. Fluorescence images of carbon dots in the whole body, in individual organs (kidney, gallbladder, and bladder), and in two cell lines from different tissue sources were observed. The results suggest not only that the carbon dots are fluorescent in solution, as reported previously, but also that they behave well as contrast agents in live mice. Moreover, metabolic process curves of carbon dots in blood and urine were obtained for the first time. Unlike quantum dots, which can persist in the body for more than 7 days, the carbon dots diffused and were excreted very quickly after injection into mice; within 3 min, fluorescence could be observed in blood, tissue and urine, indicating the rapid distribution of CDs. The fluorescence faded by approximately 4 h in organs and by approximately 10 h in urine, indicating that the CDs were excreted completely in half a day. Our results on the absorption, distribution, metabolism, and excretion of carbon dots may have great significance for the application of these CDs in drug delivery, as drug targets, and for biological imaging. We also demonstrated that these CDs have good biocompatibility for use in studies of mother-child barriers and in fluorescence imaging in plants.

Naproxen as a potential candidate for promoting rivastigmine anti-Alzheimer activity against aluminum chloride-prompted Alzheimer's-like disease in rats; neurogenesis and apoptosis modulation as a possible underlying mechanism

BACKGROUND AND AIM

Alzheimer's disease (AD) is one of the leading causes of dependence and disability among the elderly worldwide. The traditional anti-Alzheimer medication, rivastigmine, one of the cholinesterase inhibitors (ChEIs), fails to achieve a definitive cure. We tested the hypothesis that naproxen administration to the rivastigmine-treated aluminum chloride (AlCl3) Alzheimer's rat model could provide an additive neuroprotective effect compared to rivastigmine alone.

MATERIALS AND METHODS

The studied groups were control (Cont), AlCl3 treated (Al), rivastigmine treated (RIVA), naproxen treated (Napro), and combined rivastigmine and naproxen treated (RIVA + Napro). Rats' memory, spatial learning, and cognitive behavior were assessed followed by evaluation of hippocampal acetylcholinesterase (AChE) activity. Hippocampal and cerebellar histopathology were thoroughly examined. Activated caspase-3 and the neuroepithelial stem cells marker; nestin expressions were immunohistochemically assayed.

RESULTS

AD rats displayed significantly impaired memory and cognitive function, augmented hippocampal AChE activity; massive neurodegeneration associated with enhanced astrogliosis, apoptosis, and impaired neurogenesis. Except for the enhancement of neurogenesis and suppression of apoptosis, the combination therapy had no additional neuroprotective benefit over rivastigmine-only therapy.

CONCLUSION

Naproxen's efficacy was established by its ability to function at the cellular level, improved neurogenesis, and decreased, apoptosis without having an additional mitigating impact on cognitive impairment in rivastigmine-treated AD rats.

Recent Advancements in Nanodiamond Mediated Brain Targeted Drug Delivery and Bioimaging of Brain Ailments: A Holistic Review

BACKGROUND

The brain is a vital and composite organ. By nature, the innate make-up of the brain is such that in anatomical parlance, it is highly protected by the "Blood-Brain Barrier", which is a nexus of capillary endothelial cells, basement membrane, neuroglial membrane and glialpodocytes. The same barrier, which protects and isolates the interstitial fluid of the brain from capillary circulation, also restricts the therapeutic intervention. Many standing pharmaceutical formulations are ineffective in the treatment of inimical brain ailments because of the inability of the API to surpass and subsist inside the Blood Brain Barrier.

OBJECTIVE

This is an integrated review that emphasizes on the recent advancements in brain-targeted drug delivery utilizing nanodiamonds (NDs) as a carrier of therapeutic agents. NDs are a novel nanoparticulate drug delivery system, having carbon moieties as their building blocks and their surface tenability is remarkable. These neoteric carbon-based carriers have exceptional, mechanical, electrical, chemical, optical, and biological properties, which can be further rationally modified and augmented.

CONCLUSION

NDs could be the next"revolution "in the field of nanoscience for the treatment of neurodegenerative disorders, brain tumors, and other pernicious brain ailments. What sets them apart from other nanocarriers is their versatile properties like diverse size range and surface modification potential, which makes them efficient enough to move across certain biological barriers and offer a plethora of brain targeting and bioimaging abilities. Lay Summary: The blood-brain barrier (BBB) poses a major hurdle in the way of treating many serious brain ailments. A range of nanoparticle based drug delivering systems have been formulated, including solid lipid nanoparticles, liposomes, dendrimers, nanogels, polymeric NPs, metallic NPs (gold, platinum, andironoxide) and diamondoids (carbonnanotubes). Despite this development, only a few of these formulations have shown the ability to cross the BBB. Nanodiamonds, because of their small size, shape, and surface characteristics, have a potential in moving beyond the diverse and intricate BBB, and offer a plethora of brain targeting capabilities.

The molecular mechanism, targets, and novel molecules in the treatment of Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurological illness that causes dementia mainly in the elderly. The challenging obstacles related to AD has freaked global healthcare system to encourage scientists in developing novel therapeutic startegies to overcome with the fatal disease. The current treatment therapy of AD provides only symptomatic relief and to some extent disease-modifying effects. The current approach for AD treatment involves designing of cholinergic inhibitors, Aβ disaggregation inducing agents, tau inhibitors and several antioxidants. Hence, extensive research on AD therapy urgently requires a deep understanding of its pathophysiology and exploration of various chemical scaffolds to design and develop a potential drug candidate for the treatment. Various issues linked between disease and therapy need to be considered such as BBB penetration capability, clinical failure and multifaceted pathophisiology requires a proper attention to develop a lead candidate. This review article covers all probable mechanisms including one of the recent areas for investigation i.e., lipid dyshomeostasis, pathogenic involvement of P. gingivalis and neurovascular dysfunction, recently reported molecules and drugs under clinical investigations and approved by FDA for AD treatment. Our summarized information on AD will attract the researchers to understand and explore current status and structural modifications of the recently reported heterocyclic derivatives in drug development for AD therapy.

Quercetin stimulates the non-amyloidogenic pathway via activation of ADAM10 and ADAM17 gene expression in aluminum chloride-induced Alzheimer's disease rat model

AIMS

Alzheimer's disease (AD) is the most common progressive neurodegenerative disorder characterized by declined cognitive functions in the elderly. Quercetin (Q) is a potent flavonol that has neuroprotective effects on AD derangements. The present study aimed to evaluate the α-secretase stimulatory function of Q through activation of ADAM10 and ADAM17 gene expression in the aluminum chloride (AlCl3)-induced AD rat model.

MAIN METHODS

After induction of AD in rats by oral administration of AlCl3 (50 mg/kg) for 28 days, the Q doses (25 and 50 mg/kg) were orally administered for 28 days. Rats performed the behavioral assessments during the last week of the treatment period. Hippocampi were harvested for assessments of the neurochemical and histopathological examinations and gene expression analysis.

KEY FINDINGS

Administration of Q to AlCl₃-induced AD rat model attenuated behavioral deficits, improved cholinergic and dopaminergic dysfunctions, and diminished insoluble amyloid β (Aβ) plaques aggregation in the hippocampus. These ameliorative effects of Q were associated with down-regulation of APP, BACE1, APH1, and PSEN1 and up-regulation of ADAM10 and ADAM17 gene expression levels in the hippocampus.

SIGNIFICANCE

The present study suggests that Q might attenuate neurotransmission impairment, Aβ aggregation in the hippocampus, and behavioral deficits in the AlCl₃-induce AD rat model via up-regulating ADAM 10 and ADAM 17 (α-secretase) gene expression, leading to the inhibition of the amyloidogenic pathway. In support of the present finding, we suggest that ADAM10 and ADAM17 activation might be potential drug targets for AD to counteract the Aβ aggregation and cognitive deterioration.

Spermine protects aluminium chloride and iron-induced neurotoxicity in rat model of Alzheimer's disease via attenuation of tau phosphorylation, Amyloid-β (1-42) and NF-κB pathway

Alzheimer's disease (AD) is the most prevalent type of dementia, characterized by a gradual decline in cognitive and memory functions of the aged peoples. Long-term exposure to heavy metals (aluminium and iron) cause neurotoxicity by amyloid plaques accumulation, tau phosphorylation, increased oxidative stress, neuroinflammation, and cholinergic neurons degeneration, contributes to the development of AD-like symptoms. The present research work is designed to investigate the neuroprotective effect of spermine in aluminium chloride (AlCl₃), and iron (Fe) induced AD-like symptoms in rats. Rats were administered of AlCl₃ (100 mg/kg p.o.) alone and in combination with iron (120 μg/g, p.o.) for 28 days. Spermine (5 and 10 mg/kg) through intraperitoneal (i.p.) route was given for 14 days. The recognition and spatial memory impairment were tasted using Morris water maze (MWM), actophotometer, and Novel Object Recognition test (NORT). All the rats were sacrificed on day 29, brains were isolated, and tissue homogenate was used for neuroinflammatory, biochemical, neurotransmitters, metals concentration, and nuclear factor-kappa B (NF-κB) analysis. In the present study, AlCl₃ and iron administration elevated oxidative stress, cytokines release, dysbalanced neurotransmitters concentration, and biochemical changes. Rats treated with spermine dose-dependently improved the recognition and spatial memory, attenuated proinflammatory cytokine release, and restored neurotransmitters concentration and antioxidant enzymes. Spermine also mitigated the increased beta-amyloid (Aβ42), with downregulation of tau phosphorylation. Furthermore, spermine augmented the hippocampal levels of B cell leukaemia/lymphoma-2 (Bcl-2), diminished nuclear factor-kappa B (NF-κB) and caspase-3 (casp-3) expression. Moreover, spermine exhibited the neuroprotective effect through anti-inflammatory, antioxidant, neurotransmitters restoration, anti-apoptotic Aβ42 concentration.

The effect of Crocin on TFAM and PGC-1α expression and Catalase and Superoxide dismutase activities following cholestasis-induced neuroinflammation in the striatum of male Wistar rats

Bile secretion is a physiological function that is disrupted following Bile Duct Ligation (BDL) and induces cholestasis. Cholestasis is a bile flow reduction that induces apoptosis, oxidative stress, and inflammation, and alters the expression of genes. Evidence shows the relationship between cholestasis and neuroinflammation. Cholestasis via attenuating mitochondrial biogenesis and anti-oxidant activity can induce neuroinflammation and apoptosis. Mitochondrial transcriptional factor A (TFAM) and Peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) are involved in mitochondrial biogenesis, and TFAM, PGC-1α, Catalase (CAT), and Superoxide dismutase (SOD) have a role in upregulating antioxidant pathways. On the other hand, many studies have shown the neuroprotective effects of Crocin, the water-soluble carotenoid of Saffron (Crocus sativus L.). In this study, we aimed to investigate the effect of Crocin on the level of TFAM, PGC-1α, CAT, and SOD following cholestasis-induced neuroinflammation in the rat's striatum. Cholestasis was induced by BDL surgery and administration of Crocin was intraperitoneal, at the dose of 30 mg/kg every day, 24 h after BDL surgery up to thirty days. The results showed that TFAM, PGC-1α, and SOD were decreased following cholestasis; while, CAT was increased. In addition, Crocin restored the effects of cholestasis on the level of TFAM, PGC-1α, and SOD. In conclusion, Crocin may have improvement effects on cholestasis-induced neuroinflammation in the rat's striatum.

Prasugrel anti-ischemic effect in rats: Modulation of hippocampal SUMO2/3-IкBα/Ubc9 and SIRT-1/miR-22 trajectories

The beneficial role of prasugrel, a P2Y12 receptor blocker, in several neurointerventional procedures has been reviewed clinically. Beyond its antiplatelet capacity, the potential neuroprotective mechanisms of prasugrel are poorly addressed experimentally. Relevant to the imbalance between neuro-inflammation and neuroprotective pathways in cerebral ischemia/reperfusion (I/R), our study evaluated the anti-ischemic potential of prasugrel treatment through tackling novel targets. Male Wistar rats were allocated into 2 sets; set 1 (I/R 60 min/3 days) to assess the neurological deficits/biochemical impact of prasugrel and set 2 (I/R 60 min/5 days) for evaluating short memory/morphological/immunoreactive changes. Each set comprised 4 groups designated as sham, sham + prasugrel, I/R, and I/R + prasugrel. Post-administration of prasugrel for 3 and 5 days reduced neurological deficit scores and improved the spontaneous activity/short term spatial memory using the Y-maze paradigm. On the molecular level, prasugrel turned off SUMO2/3-inhibitory kappa (Iκ)Bα, Ubc9 and nuclear factor kappa (NF-κ)B. Besides, it inhibited malondialdehyde (MDA) and inactivated astrocytes by downregulating the glial fibrillary acidic protein (GFAP) hippocampal immune-expression. Conversely, it activated its target molecule cAMP, protein kinase (PK)A, and cAMP response element-binding protein (CREB) to enhance the brain-derived nuclear factor (BDNF) hippocampal content. Additionally, cAMP/PKA axis increased the hippocampal content of deacetylator silent information regulator 1 (SIRT1) and the micro RNA (miR)-22 gene expression. The crosstalk between these paths partakes in preserving hippocampal cellularity. Accordingly, prasugrel, regardless inhibiting platelets activity, modulated other cellular components; viz., SUMO2/3-IκBα/Ubc9/NF-κB, cAMP/PKA related trajectories, CREB/BDNF and SIRT1/miR-22 signaling, besides inhibiting GFAP and MDA to signify its anti-ischemic potential.

The neuroprotective effect of pretreatment with carbon dots from Crinis Carbonisatus (carbonized human hair) against cerebral ischemia reperfusion injury

BACKGROUND

Cerebral infarction and cerebral hemorrhage, also known as "stroke", is one of the leading cause of death. At present, there is no real specific medicine for stroke. Crinis Carbonisatus (named Xue-yu-tan in Chinese), produced from carbonized hair of healthy human, and has been widely applied to relieve pain and treat epilepsy, stroke and other diseases in China for thousands of years.

RESULTS

In this work, a new species of carbon dots derived from Crinis Carbonisatus (CrCi-CDs) were separated and identified. And the neuroprotective effect of carbon dots from CrCi were evaluated using the middle cerebral artery occlusion (MCAO) model. Neurological deficit score and infarction volume was assessed, evans blue content of ischemic hemispheres was measured, the concentrations of inflammatory factors, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) in the cortex were measured, and the levels of neurotransmitters in the brain were determined. Preconditioning of CrCi-CDs significantly reduced ischemic lesion volume and blood-brain-barrier (BBB) permeability, improved neurologic deficits, decreased the level of TNF-α and IL-6 in MCAO rats, inhibited excitatory neurotransmitters aspartate (Asp) and glutamate (Glu), and increased the level of 5-hydroxytryptamine (5-HT). The RNA-Sequencing results reveal that further potential mechanisms behind the activities may be related to the anti-inflammation effects and inhibition of neuroexcitatory toxicity.

CONCLUSION

CrCi-CDs performs neuroprotective effect on cerebral ischemia and reperfusion injury, and the mechanisms may correlate with its anti-inflammatory action, which suggested that CrCi-CDs have potential value in clinical therapy on the acute apoplexy cases in combination with thrombolytic drugs.

Antiamnesic and Neuroprotective Effects of an Aqueous Extract of Ziziphus jujuba Mill. (Rhamnaceae) on Scopolamine-Induced Cognitive Impairments in Rats

Background

Alzheimer's disease is a neurological condition that affects about 44 million people worldwide. The available treatments target symptoms rather than the underlying causes. Ziziphus jujuba (Rhamnaceae) is widely used in traditional Cameroonian medicine to treat diabetes, pain, infections, and dementia. Previous studies reported that Z. jujuba aqueous macerate improves working memory impairment, but no study on the antiamnesic effect of a concoction of Z. jujuba in rats has been performed. Therefore, this study aimed to assess the antiamnesic and neuroprotective effects of an aqueous extract of Z. jujuba on scopolamine-induced cognitive impairments in rats.

Methods

Learning and memory impairments were induced in rats by administering scopolamine (1 mg/kg, i.p.) to 58 rats for 15 days. Rats that developed learning and memory impairments in Morris water maze and Y-maze paradigms were divided into 7 groups (8 rats each) and treated daily for 15 days as follows: the normal control group received distilled water (10 ml/kg, p.o.), the negative control group received distilled water (10 ml/kg, p.o.), positive control groups either received donepezil (1.2 mg/kg, p.o.) or tacrine (10 mg/kg, p.o.), and the three test groups were given the extract (29, 57, and 114 mg/kg, p.o.). At the end of treatments, learning and memory impairments were determined using the same paradigms. Animals were then euthanized, and biochemical parameters of oxidative stress, inflammation, and apoptosis were analyzed in the hippocampus and prefrontal cortex.

Results

On the 4th day of the acquisition phase in the Morris water maze, Z. jujuba (29 and 114 mg/kg) reduced (p < 0.001) the latency to reach the platform, while in the retention phase, Z. jujuba (57 and 114 mg/kg) decreased (p < 0.001) the time to reach the platform and increased the time in the target quadrant (p < 0.05) compared to control. Surprisingly, the extract failed to affect spontaneous alternations in the Y-maze. Furthermore, the extract (29, 57, and 114 mg/kg) reversed (p < 0.001) scopolamine-induced oxidative stress, inflammation, and apoptosis. This was supported by the reduction of neuronal alterations in the hippocampus and prefrontal cortex.

Conclusions

Compared to donepezil, a standard drug against Alzheimer's disease, these findings suggest that Z. jujuba extract possesses antiamnesic and neuroprotective effects, and these effects are mediated in part through antioxidant, anti-inflammatory, and antiapoptotic activities. These findings help to explain its use in treating psychiatric disorders in Cameroon's folk medicine.

Benincasa hispida alleviates amyloid pathology by inhibition of Keap1/Nrf2-axis: Emphasis on oxidative and inflammatory stress involved in Alzheimer's disease model

OBJECTIVES

Alzheimer's disease is a progressive neurodegenerative disorder with cognitive and memory impairment. Benincasa hispida is being used in the treatment of various neurological diseases in Ayurveda system of medicine. The objective of the study was to investigate the effect of Benincasa hispida fruit extract in the Alzheimer's disease rats.

METHODS

Benincasa hispida fruits extract was administered orally for 16 weeks at doses of 250 and 500-mg/kg/day. The cognitive deficits were examined by behavioural tests like Morris water maze test, Y-maze and rota-rod test. Biochemical and neurochemical analysis of Acetylcholine, dopamine, serotonin levels and anti-oxidant, anti-inflammatory markers were evaluated and the mRNA expression of Keap/Nrf2 axis was analysed by RT-PCR.

RESULTS

Aluminum chloride (AlCl₃) induction altered the behavioural profile and produced significant alterations in the cortical and hippocampal regions of the brain and the treatment with Benincasa hispida extract at doses of 250-mg/kg/day (p<0.05) and 500mg/kg/day (p<0.05) alleviated the acetylcholine, dopamine and serotonin neurotransmitter levels. The antioxidant enzyme markers such as superoxide dismutase (SOD), Catalase (CAT), glutathione (GSH) were increased and the oxidative stress marker malondialdehyde(MDA) was decreased. The inflammatory cytokine levels of TNF-α, IL-1β were decreased in Alzheimer's disease induced rats. We further estimated Keap/Nrf2/HO-1 genes these anti-oxidant genes were upregulated(p < 0.001) in treatment groups. Further, the neuroprotective activity of Benincasa was further confirmed by histopathological studies of hippocampal CA3 fields.

CONCLUSIONS

The findings of the current study indicates Benincasa hispida as a possible neuroprotective alternative for Alzheimer's disease.

Ziziphus jujuba (Rhamnaceae) Alleviates Working Memory Impairment and Restores Neurochemical Alterations in the Prefrontal Cortex of D-Galactose-Treated Rats

Alzheimer's disease is a progressive cognitive dysfunction. However, pharmacological treatments are symptomatic and have many side effects, opening the opportunity to alternative medicine. This study investigated the antiamnesic effect of the aqueous extract of Ziziphus jujuba on D-galactose-induced working memory impairment in rats. Impairment of working memory was induced by subcutaneous (s.c.) injection of D-galactose (350 mg/kg/day) to rats for 21 days. These animals were then subjected to object recognition and Y-maze tests. Rats with confirmed memory impairment were treated per os (p.o.) with tacrine (10 mg/kg), aspirin (20 mg/kg, p.o.), extract (41.5, 83, and 166 mg/kg, p.o.), and distilled water (10 mL/kg, p.o.) daily for 14 days. At the end of the treatments, alteration in working memory was assessed using the above paradigms. Afterward, these animals were euthanized, and cholinergic, proinflammatory, and neuronal damage markers were analyzed in the prefrontal cortex. Rats administered D-galactose and treated with distilled water had impaired working memory (evidenced by decreased time spent on the novel object and discrimination index) and decreased spontaneous alternation in the Y-maze. D-galactose also decreased the levels of acetylcholinesterase and acetylcholine and increased the level of glial fibrillary acidic protein, ionized calcium-binding adapter molecule 1, tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL-1β), interleukin 6 (IL-6), and interferon-gamma (IFN-γ). Treatment with the extract (166 mg/kg) reversed the time spent on the novel object and the discrimination index. It equally increased the percentage of spontaneous alternation. Neurochemical analysis revealed that the extract markedly alleviated acetylcholinesterase activity and neuroinflammation. These observations were corroborated by the reduction in neuronal loss. Taken together, these results suggest that Ziziphus jujuba aqueous extract possesses an antiamnesic effect. This effect seems to involve cholinergic and anti-inflammatory modulations. This, therefore, claims using this plant in the treatment of dementia in Cameroon subject to further studies and trials.

Cerebroprotein hydrolysate-I protects senescence-induced by D-galactose in PC12 cells and mice

Cerebroprotein hydrolysate-I (CH-I)，a mixture of peptides extracted from porcine brain tissue，has shown a neuroprotective effect, but its role in brain senescence is unclear. In the present study, we established a senescence model of PC12 cells and mice to investigate the effect of CH-I on brain senescence via JAK2/STAT3 pathway. The results showed that CH-I could improve cell viability, inhibit the apoptosis of cells, and reduce the senescence-positive cells induced by D-galactose. In vivo, CH-I improved the learning ability and memory of aging mice, reduced neuronal damage in mice hippocampus. Mechanism studies showed that CH-I could adjust BDNF protein expressions, activate JAK2/STAT3 pathway, and finally enhance telomerase activity. All these findings indicated that CH-I showed a neuroprotective effect against brain senescence. These results might provide further reference and support for the application of CH-I in delaying aging.

Neurotrophic Factors in Parkinson's Disease: Clinical Trials, Open Challenges and Nanoparticle-Mediated Delivery to the Brain

Neurotrophic factors (NTFs) are small secreted proteins that support the development, maturation and survival of neurons. NTFs injected into the brain rescue and regenerate certain neuronal populations lost in neurodegenerative diseases, demonstrating the potential of NTFs to cure the diseases rather than simply alleviating the symptoms. NTFs (as the vast majority of molecules) do not pass through the blood-brain barrier (BBB) and therefore, are delivered directly into the brain of patients using costly and risky intracranial surgery. The delivery efficacy and poor diffusion of some NTFs inside the brain are considered the major problems behind their modest effects in clinical trials. Thus, there is a great need for NTFs to be delivered systemically thereby avoiding intracranial surgery. Nanoparticles (NPs), particles with the size dimensions of 1-100 nm, can be used to stabilize NTFs and facilitate their transport through the BBB. Several studies have shown that NTFs can be loaded into or attached onto NPs, administered systemically and transported to the brain. To improve the NP-mediated NTF delivery through the BBB, the surface of NPs can be functionalized with specific ligands such as transferrin, insulin, lactoferrin, apolipoproteins, antibodies or short peptides that will be recognized and internalized by the respective receptors on brain endothelial cells. In this review, we elaborate on the most suitable NTF delivery methods and envision "ideal" NTF for Parkinson's disease (PD) and clinical trial thereof. We shortly summarize clinical trials of four NTFs, glial cell line-derived neurotrophic factor (GDNF), neurturin (NRTN), platelet-derived growth factor (PDGF-BB), and cerebral dopamine neurotrophic factor (CDNF), that were tested in PD patients, focusing mainly on GDNF and CDNF. We summarize current possibilities of NP-mediated delivery of NTFs to the brain and discuss whether NPs have impact in improving the properties of NTFs and delivery across the BBB. Emerging delivery approaches and future directions of NTF-based nanomedicine are also discussed.

Dimethyl fumarate abridged tauo-/amyloidopathy in a D-Galactose/ovariectomy-induced Alzheimer's-like disease: Modulation of AMPK/SIRT-1, AKT/CREB/BDNF, AKT/GSK-3β, adiponectin/Adipo1R, and NF-κB/IL-1β/ROS trajectories

Since the role of estrogen in postmenauposal-associated dementia is still debatable, this issue urges the search for other medications. Dimethyl fumarate (DMF) is a drug used for the treatment of multiple sclerosis and has shown a neuroprotective effect against other neurodegenerative diseases. Accordingly, the present study aimed to evaluate the effect of DMF on an experimental model of Alzheimer disease (AD) using D-galactose (D-Gal) administered to ovariectomized (OVX) rats, resembling a postmenopausal dementia paradigm. Adult 18-month old female Wistar rats were allocated into sham-operated and OVX/D-Gal groups that were either left untreated or treated with DMF for 56 days starting three weeks after sham-operation or ovariectomy. DMF succeeded to ameliorate cognitive (learning/short- and long-term memory) deficits and to enhance the dampened overall activity (NOR, Barnes-/Y-maze tests). These behavioral upturns were associated with increased intact neurons (Nissl stain) and a reduction in OVX/D-Gal-mediated hippocampal CA1 neurodegeneration and astrocyte activation assessed as GFAP immunoreactivity. Mechanistically, DMF suppressed the hippocampal contents of AD-surrogate markers; viz., apolipoprotein (APO)-E1, BACE1, Aβ42, and hyperphosphorylated Tau. Additionally, DMF has augmented the neuroprotective parameters p-AKT, its downstream target CREB and BDNF. Besides, it activated AMPK, and enhanced SIRT-1, as well as antioxidant defenses (SOD, GSH). On the other hand, DMF inhibited the transcription factor NF-κB, IL-1β, adiponectin/adiponectin receptor type (AdipoR)1, GSK-3β, and MDA. Accordingly, in this postmenopausal AD model, DMF treatment by pursuing the adiponectin/AdipoR1, AMPK/SIRT-1, AKT/CREB/BDNF, AKT/GSK-3β, and APO-E1 quartet hampered the associated tauo-/amyloidopathy and NF-κB-mediated oxidative/inflammatory responses to advance insights into its anti-amnesic effect.

Focal Subcortical White Matter Lesions Disrupt Resting State Cortical Interhemispheric Functional Connectivity in Mice

The corpus callosum is the largest white matter tract and critical for interhemispheric connectivity. Unfortunately, neurocognitive deficits after experimental white matter lesions are subtle and variable, limiting their translational utility. We examined resting state functional connectivity (RSFC) as a surrogate after a focal lesion in the lateral corpus callosum induced by stereotaxic injection of L-NIO in mice. RSFC was performed via optical intrinsic signal imaging through intact skull before and on days 1 and 14 after injection, using interhemispheric homotopic and seed-based temporal correlation maps. We measured the lesion volumes at 1 month in the same cohort. L-NIO induced focal lesions in the corpus callosum. Interhemispheric homotopic connectivity decreased by up to 50% 24 h after L-NIO, partially sparing the visual cortex. All seeds showed loss of connectivity to the contralateral hemisphere. Moreover, ipsilesional motor and visual cortices lost connectivity within the same hemisphere. Sham-operated mice did not show any lesion or connectivity changes. RSFC imaging reliably detects acute disruption of long interhemispheric and intrahemispheric connectivity after a corpus callosum lesion in mice. This noninvasive method can be a functional surrogate to complement neurocognitive testing in both therapeutic and recovery studies after white matter injury.

The application of multifunctional nanomaterials in Alzheimer's disease: A potential theranostics strategy

By virtue of their small size, nanomaterials can cross the blood-brain barrier and, when modified to target specific cells or regions, can achieve high bioavailability at the intended site of action. Modified nanomaterials are therefore promising agents for the diagnosis and treatment of neurodegenerative diseases such as Alzheimer's disease (AD). Here we review the roles and mechanisms of action of nanomaterials in AD. First, we discuss the general characteristics of nanomaterials and their application to nanomedicine. Then, we summarize recent studies on the diagnosis and treatment of AD using modified nanomaterials. These studies indicate that using nanomaterials is a potential strategy for AD treatment by slowing the progression of AD through enhanced therapeutic effects.

Exploring the Potential Mechanism of Guchang Zhixie Wan for Treating Ulcerative Colitis by Comprehensive Network Pharmacological Approaches and Molecular Docking Validation as Well as Cell Experiments

Guchang Zhixie Wan (GZW) is a commonly used Chinese medicine for the treatment of ulcerative colitis (UC). This research explored the potential pharmacological mechanism of GZW in UC. The active ingredients, potential targets, and UC-related genes of GZW were retrieved from public databases. The pharmacological mechanisms including key components, potential targets and signal pathways were determined through bioinformatics analysis. The results of this study were verified through virtual molecular docking and cell experiments. Network analysis revealed that 26 active GZW compounds and 148 potential GZW target proteins were associated with UC. Quercetin, kaempferol and β-sitosterol were identified as the core active ingredients of GZW. IFNG, IL-1A, IL-1B, JUN, RELA, and STAT1 were indicated as key targets of GZW. These key targets have a strong affinity for quercetin, kaempferol, and β-sitosterol. GO and KEGG enrichment analysis showed that GZW target proteins are highly enriched in inflammatory, immune, and oxidative stress-related pathways. This study confirmed the therapeutic effect and revealed potential molecular mechanism of GZW on UC. And the protective effects of GZW on inflammatory bowel disease pathway were also revealed through STAT3/NF-κB/IL-6 pathway. The findings of this study enhanced our understanding of GZW in the treatment of UC and provided a feasible method for discovering potential drugs from traditional Chinese medicine formulations.

K284-6111 alleviates memory impairment and neuroinflammation in Tg2576 mice by inhibition of Chitinase-3-like 1 regulating ERK-dependent PTX3 pathway

Background

Alzheimer’s disease (AD) is one of the most prevalent neurodegenerative disorders characterized by gradual memory loss and neuropsychiatric symptoms. We have previously demonstrated that the 2-({3-[2-(1-cyclohexene-1-yl)ethyl]-6,7-dimethoxy-4-oxo-3,4-dihydro-2-quinazolinyl}sulfanyl)-N-(4-ethylphenyl)butanamide (K284-6111), the inhibitor of CHI3L1, has the inhibitory effect on memory impairment in Αβ infusion mouse model and on LPS-induced neuroinflammation in the murine BV-2 microglia and primary cultured astrocyte.

Methods

In the present study, we investigated the inhibitory effect of K284-6111 on memory dysfunction and neuroinflammation in Tg2576 transgenic mice, and a more detailed correlation of CHI3L1 and AD. To investigate the effects of K284-6111 on memory dysfunction, we administered K284-6111 (3 mg/kg, p.o.) daily for 4 weeks to Tg2576 mice, followed by behavioral tests of water maze test, probe test, and passive avoidance test.

Results

Administration of K284-6111 alleviated memory impairment in Tg2576 mice and had the effect of reducing the accumulation of Aβ and neuroinflammatory responses in the mouse brain. K284-6111 treatment also selectively inactivated ERK and NF-κB pathways, which were activated when CHI3L1 was overexpressed, in the mouse brain and in BV-2 cells. Web-based gene network analysis and our results of gene expression level in BV-2 cells showed that CHI3L1 is closely correlated with PTX3. Our result revealed that knockdown of PTX3 has an inhibitory effect on the production of inflammatory proteins and cytokines, and on the phosphorylation of ERK and IκBα.

Conclusion

These results suggest that K284-6111 could improve memory dysfunction by alleviating neuroinflammation through inhibiting CHI3L1 enhancing ERK-dependent PTX3 pathway.

Methylphenidate and Rosmarinus officinalis improves cognition and regulates inflammation and synaptic gene expression in AlCl3-induced neurotoxicity mouse model

Methylphenidate (MPH), a psychotropic medication is commonly used for children with attention deficit hyperactivity disorder (ADHD). In this study we elucidated the neuroprotective and anti-inflammatory effects of MPH and Rosmarinus officinalis (rosemary) extract, an ancient aromatic herb with several applications in traditional medicine. Briefly, six groups of mice (n = 8 each group), were specified for the study and behavioral analysis was performed to analyze spatial memory followed by histological assessment and gene expression analysis of synaptic (Syn I, II and III) and inflammatory markers (IL-6, TNFα and GFAP) via qRT-PCR, in an AlCl₃-induced mouse model for neurotoxicity. The behavioral analysis demonstrated significant cognitive decline, memory defects and altered gene expression in AlCl₃-treated group. Rosemary extract significantly decreased the expression of inflammatory and synaptic markers to the similar levels as that of MPH. The present findings suggested the neuroprotective potential of Rosmarinus officinalis extract. However, further characterization of its anti-inflammatory and neuroprotective properties and MPH is required to strategize future treatments for several neurological and neurodegenerative disorders, including Alzheimer's disease.

UPLC-Orbitrap HRMS metabolic profiling of Cymbopogon citratus cultivated in Egypt; neuroprotective effect against AlCl3-induced neurotoxicity in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Cymbopogon citratus (lemongrass) is commonly used in teas, soups and treat inflammatory-based ailments, vascular and nervous disorders.

AIM OF THE STUDY

The study aimed to evaluate the neuroprotective effect of Cymbopogon citratus leaves through scientific protocol. The effect of aqueous (AE) and ethanolic (EE) extracts was evaluated against AlCl₃-induced Alzheimer's disease (AD) in rats. Metabolic profiling of the plant, isolation of bioactive compounds and standardization of the active fraction were investigated.

MATERIALS AND METHODS

AE of Cymbopogon citratus leaves was prepared as per traditional method (infusion), EE was prepared by repeated maceration in 90% ethanol, bioactive fraction (BAEE) was obtained from EE and the active compounds thereof were obtained by column chromatography. Metabolic profiling of Cymbopogon citratus was performed by UPLC-Orbitrap HRMS and HPLC was used for standardization. AlCl₃-induced Alzheimer's rats were used to assess neuroprotective effect of the extracts. Neuroprotective mechanism(s) of Cymbopogon citratus extracts was clarified through histopathological examination of brain tissues, estimation of AD biochemical markers, oxidative stress and neuroinflammation in brain homogenates. In addition, antioxidant (using DPPH assay) and anticholinesterase (using modified Ellman's method) activities were investigated.

RESULTS

AlCl₃-treated rats (17 mg/kg/day) showed histopathological alteration in brain tissues together with elevated levels of Aβ, tau proteins, MDA, NF-kB and IL-6. However, treatment with AE and EE of Cymbopogon citratus leaves prevented the pathological changes and maintained the levels of oxidative stress and inflammatory markers. In addition, BAEE significantly inhibited acetylcholinesterase enzyme (2.11 ± 0.11 mg/ml) and exhibited a strong antioxidant activity (24.99 ± 0.00 μg/ml). UPLC-MS of Cymbopogon citratus leaves showed peaks for twenty-eight compounds, twenty-one of them were identified. Three flavonoids; isoorientin, isoschaftoside and luteolin-7-O-neohesperidoside were isolated from BAEE as major constituents. The powdered leaves of Cymbopogon citratus was found to contain remarkable amounts of caffeic acid (3.49 mg/g dry wt.) and isoorientin (7.37 mg/g dry wt.) as determined by HPLC.

CONCLUSION

Cymbopogon citratus ethanolic extract attenuates AlCl₃-induced neurotoxicity in rats through inhibition of oxidative stress and inflammatory markers. This effect could possibly attributed, in part to its high content of phenolic acids and flavonoids. Accordingly, we recommend Cymbopogon citratus leaves for protection against AD.