Oral Administration of Alpha Linoleic Acid Rescues Aβ-Induced Glia-Mediated Neuroinflammation and Cognitive Dysfunction in C57BL/6N Mice

Omega-3 blood biomarkers relate to brain glucose uptake in individuals at risk of Alzheimer's disease dementia

INTRODUCTION

Brain glucose hypometabolism is a preclinical feature of Alzheimer's disease (AD). Dietary omega-3 fatty acids promote brain glucose metabolism, but clinical research is incipient. Circulating omega-3s objectively reflect their dietary intake.

METHODS

This was a cross-sectional study in 320 cognitively unimpaired participants at increased risk of AD dementia. Using lipidomics, we determined blood docosahexaenoic (DHA) and alpha-linolenic (ALA) acid levels (omega-3s from marine and plant origin, respectively). We assessed brain glucose metabolism using [18-F]-fluorodeoxyglucose (FDG) positron emission tomography (PET).

RESULTS

Blood ALA directly related to FDG uptake in brain areas known to be affected in AD. Stronger associations were observed in apolipoprotein E ε4 carriers and homozygotes. For DHA, significant direct associations were restricted to amyloid beta-positive tau-positive participants.

DISCUSSION

Blood omega-3 directly relate to preserved glucose metabolism in AD-vulnerable brain regions in individuals at increased risk of AD dementia. This adds to the benefits of omega-3 supplementation in the preclinical stage of AD dementia.

Highlights

Blood omega-3s were related to brain glucose uptake in participants at risk of Alzheimer's disease (AD) dementia.Complementary associations were observed for omega-3 from marine and plant sources.Foods rich in omega-3 might be useful in early features of AD.

Estimating the therapeutic potential of NSAIDs and linoleic acid-isomers supplementation against neuroinflammation

Nonsteroidal anti-inflammatory drugs (NSAIDs) regulate inflammation, which is associated with their role in preventing neurodegenerative diseases in epidemiological studies. It has sparked interest in their unconventional application for reducing neuroinflammation, opening up new avenues in biomedical research. However, given the pharmacological drawbacks of NSAIDs, the development of formulations with naturally antioxidant/anti-inflammatory dietary fatty acids has been demonstrated to be advantageous for the clinical translation of anti-inflammatory-based therapies. It includes improved blood-brain barrier (BBB) permeability and reduced toxicity. It permits us to speculate about the value of linoleic acid (LA)-isomers in preventing and treating neuroinflammatory diseases compared to NSAIDs. Our research delved into the impact of various factors, such as administration route, dosage, timing of intervention, and BBB permeability, on the efficacy of NSAIDs and LA-isomers in preclinical and clinical settings. We conducted a systematic comparison between NSAIDs and LA-isomers regarding their therapeutic effectiveness, BBB compatibility, and side effects. Additionally, we explored their underlying mechanisms in addressing neuroinflammation. Through our analysis, we've identified challenges and drawn conclusions that could propel advancements in treating neurodegenerative diseases and inform the development of future alternative therapeutic strategies.

A Genome-Wide Interaction Study of Erythrocyte ω-3 Polyunsaturated Fatty Acid Species and Memory in the Framingham Heart Study Offspring Cohort

BACKGROUND

Cognitive decline, and more specifically Alzheimer's disease, continues to increase in prevalence globally, with few, if any, adequate preventative approaches. Several tests of cognition are utilized in the diagnosis of cognitive decline that assess executive function, short- and long-term memory, cognitive flexibility, and speech and motor control. Recent studies have separately investigated the genetic component of both cognitive health, using these measures, and circulating fatty acids.

OBJECTIVES

We aimed to examine the potential moderating effect of main species of ω-3 polyunsaturated fatty acids (PUFAs) on an individual's genetically conferred risk of cognitive decline.

METHODS

The Offspring cohort from the Framingham Heart Study was cross-sectionally analyzed in this genome-wide interaction study (GWIS). Our sample included all individuals with red blood cell ω-3 PUFA, genetic, cognitive testing (via Trail Making Tests [TMTs]), and covariate data (N = 1620). We used linear mixed effects models to predict each of the 3 cognitive measures (TMT A, TMT B, and TMT D) by each ω-3 PUFA, single nucleotide polymorphism (SNP) (0, 1, or 2 minor alleles), ω-3 PUFA by SNP interaction term, and adjusting for sex, age, education, APOE ε4 genotype status, and kinship (relatedness).

RESULTS

Our analysis identified 31 unique SNPs from 24 genes reaching an exploratory significance threshold of 1×10-5. Fourteen of the 24 genes have been previously associated with the brain/cognition, and 5 genes have been previously associated with circulating lipids. Importantly, 8 of the genes we identified, DAB1, SORCS2, SERINC5, OSBPL3, CPA6, DLG2, MUC19, and RGMA, have been associated with both cognition and circulating lipids. We identified 22 unique SNPs for which individuals with the minor alleles benefit substantially from increased ω-3 fatty acid concentrations and 9 unique SNPs for which the common homozygote benefits.

CONCLUSIONS

In this GWIS of ω-3 PUFA species on cognitive outcomes, we identified 8 unique genes with plausible biology suggesting individuals with specific polymorphisms may have greater potential to benefit from increased ω-3 PUFA intake. Additional replication in prospective settings with more diverse samples is needed.

Biochemical Composition and Related Potential Nutritional and Health Properties of Sobrassada de Mallorca

'Sobrassada de Mallorca' is an EU PGI (Protected Geographical Indication) -qualified traditional food with important historical, social, and gastronomical relevance. However, its nutritional features are poorly characterized. Here, we studied 15 samples of Sobrassada de Mallorca (SM) and 9 samples of 'Sobrassada de Mallorca de Porc Negre' (SMBP), which are the two types of sobrassada that are PGI-protected. Their composition was assessed under the light of the EU Regulation 1924/2006 on nutrition and health claims (NHC) made on food. Results show the notably high energetic density (588 and 561 kcal/100 g for SM and SMBP, respectively) due to the notable fatty acid (FA) content and the relatively high proportion of unsaturated FAs (≈61% of total FAs) is also noted, mainly oleic acid (39.7 and 45.7%). Moreover, analyses showed that 100 g of both types of 'Sobrassada de Mallorca' present a 'significant' content (at least 15% of the established Nutrient Reference Values) of vitamins A (241 and 232 µg), E (2.67 and 2.67 mg), B3 (3.50 and 2.43 mg), B6 (0.27 and 0.35 mg), B12 (0.65 and 0.56 µg), phosphorus (271 and 186 mg), and selenium (17.3 and 16.2 µg) as defined by the EU standards and, in essence, their associated health benefits can be claimed for both SM and SMBP or foods containing them. In principle, SM and SMBP could be associated with various health claims (HC), including those related to energy-yielding metabolism, normal functioning of the immune system, and reduction of tiredness and fatigue.

From Liver to Brain: How MAFLD/MASLD Impacts Cognitive Function

Metabolic dysfunction-associated fatty liver disease or metabolic dysfunction-associated steatotic liver disease (MAFLD/MASLD), is a common chronic liver condition affecting a substantial global population. Beyond its primary impact on liver function, MAFLD/MASLD is associated with a myriad of extrahepatic manifestations, including cognitive impairment. The scope of cognitive impairment within the realm of MAFLD/MASLD is a matter of escalating concern. Positioned as an intermediate stage between the normal aging process and the onset of dementia, cognitive impairment manifests as a substantial challenge associated with this liver condition. Insights from studies underscore the presence of compromised executive function and a global decline in cognitive capabilities among individuals identified as being at risk of progressing to liver fibrosis. Importantly, this cognitive impairment transcends mere association with metabolic factors, delving deep into the intricate pathophysiology characterizing MAFLD/MASLD. The multifaceted nature of cognitive impairment in the context of MAFLD/MASLD is underlined by a spectrum of factors, prominently featuring insulin resistance, lipotoxicity, and systemic inflammation as pivotal contributors. These factors interplay within the intricate landscape of MAFLD/MASLD, fostering a nuanced understanding of the links between hepatic health and cognitive function. By synthesizing the available evidence, exploring potential mechanisms, and assessing clinical implications, the overarching aim of this review is to contribute to a more complete understanding of the impact of MAFLD/MASLD on cognitive function.

Important roles of linoleic acid and α-linolenic acid in regulating cognitive impairment and neuropsychiatric issues in metabolic-related dementia

Metabolic syndrome (MetS), which is characterized by insulin resistance, high blood glucose, obesity, and dyslipidemia, is known to increase the risk of dementia accompanied by memory loss and depression. The direct pathways and specific mechanisms in the central nervous system (CNS) for addressing fatty acid imbalances in MetS have not yet been fully elucidated. Among polyunsaturated acids, linoleic acid (LA, n6-PUFA) and α-linolenic acid (ALA, n3-PUFA), which are two essential fatty acids that should be provided by food sources (e.g., vegetable oils and seeds), have been reported to regulate various cellular mechanisms including apoptosis, inflammatory responses, mitochondrial biogenesis, and insulin signaling. Furthermore, inadequate intake of LA and ALA is reported to be involved in neuropathology and neuropsychiatric diseases as well as imbalanced metabolic conditions. Herein, we review the roles of LA and ALA on metabolic-related dementia focusing on insulin resistance, dyslipidemia, synaptic plasticity, cognitive function, and neuropsychiatric issues. This review suggests that LA and ALA are important fatty acids for concurrent treatment of both MetS and neurological problems.

Gut microbiota-induced CXCL1 elevation triggers early neuroinflammation in the substantia nigra of Parkinsonian mice

Gut microbiota disturbance and systemic inflammation have been implicated in the degeneration of dopaminergic neurons in Parkinson's disease (PD). How the alteration of gut microbiota results in neuropathological events in PD remains elusive. In this study, we explored whether and how environmental insults caused early neuropathological events in the substantia nigra (SN) of a PD mouse model. Aged (12-month-old) mice were orally administered rotenone (6.25 mg·kg-1·d-1) 5 days per week for 2 months. We demonstrated that oral administration of rotenone to ageing mice was sufficient to establish a PD mouse model and that microglial activation and iron deposition selectively appeared in the SN of the mice prior to loss of motor coordination and dopaminergic neurons, and these events could be fully blocked by microglial elimination with a PLX5622-formulated diet. 16 S rDNA sequencing analysis showed that the gut microbiota in rotenone-treated mice was altered, and mice receiving faecal microbial transplantation (FMT) from ageing mice treated with rotenone for 2 months exhibited the same pathology in the SN. We demonstrated that C-X-C motif chemokine ligand-1 (CXCL1) was an essential molecule, as intravenous injection of CXCL1 mimicked almost all the pathology in serum and SN induced by oral rotenone and FMT. Using metabolomics and transcriptomics analyses, we identified the PPAR pathway as a key pathway involved in rotenone-induced neuronal damage. Inhibition of the PPARγ pathway was consistent in the above models, whereas its activation by linoleic acid (60 mg·kg-1·d-1, i.g. for 1 week) could block these pathological events in mice intravenously injected with CXCL1. Altogether, these results reveal that the altered gut microbiota resulted in neuroinflammation and iron deposition occurring early in the SN of ageing mice with oral administration of rotenone, much earlier than motor symptoms and dopaminergic neuron loss. We found that CXCL1 plays a crucial role in this process, possibly via PPARγ signalling inhibition. This study may pave the way for understanding the "brain-gut-microbiota" molecular regulatory networks in PD pathogenesis. The aged C57BL/6 male mice with rotenone intragastric administration showed altered gut microbiota, which caused systemic inflammation, PPARγ signalling inhibition and neuroinflammation, brain iron deposition and ferroptosis, and eventually dopaminergic neurodegeneration in PD.

Unraveling the impact of Omega-3 polyunsaturated fatty acids on blood-brain barrier (BBB) integrity and glymphatic function

Alzheimer's disease (AD) and other forms of dementia represent major public health challenges but effective therapeutic options are limited. Pathological brain aging is associated with microvascular changes and impaired clearance systems. The application of omega-3 polyunsaturated fatty acids (n-3 or omega-3 PUFAs) is one of the most promising nutritional interventions in neurodegenerative disorders from epidemiological data, clinical and pre-clinical studies. As essential components of neuronal membranes, n-3 PUFAs have shown neuroprotection and anti-inflammatory effects, as well as modulatory effects through microvascular pathophysiology, amyloid-beta (Aβ) clearance and glymphatic pathways. This review meticulously explores these underlying mechanisms that contribute to the beneficial effects of n-3 PUFAs against AD and dementia, synthesizing evidence from both animal and interventional studies.

Trichosanthis Semen Exerts Neuroprotective Effects in Alzheimer's Disease Models by Inhibiting Amyloid-β Accumulation and Regulating the Akt and ERK Signaling Pathways

Background

Alzheimer's disease (AD), the most common form of dementia, is characterized by memory loss and the abnormal accumulation of senile plaques composed of amyloid-β (Aβ) protein. Trichosanthis Semen (TS) is a traditional herbal medicine used to treat phlegm-related conditions. While TS is recognized for various bioactivities, including anti-neuroinflammatory effects, its ability to attenuate AD remains unknown.

Objective

To evaluate the effects of TS extract (TSE) on neuronal damage, Aβ accumulation, and neuroinflammation in AD models.

Methods

Thioflavin T and western blot assays were used to assess effects on Aβ aggregation in vitro. TS was treated to PC12 cells with Aβ to assess the neuroprotective effects. Memory functions and histological brain features were investigated in TSE-treated 5×FAD transgenic mice and mice with intracerebroventricularly injected Aβ.

Results

TSE disrupted Aβ aggregation and increased the viability of cells and phosphorylation of both protein kinase B (Akt) and extracellular signal-regulated kinase (ERK) in vitro. TSE treatment also suppressed the accumulation of Aβ plaques in the brain of 5×FAD mice, protected neuronal cells in both the subiculum and medial septum, and upregulated Akt/ERK phosphorylation in the hippocampus. Moreover, TSE ameliorated the memory decline and glial overactivation observed in 5×FAD mice. As assessing whether TS affect Aβ-induced neurotoxicity in the Aβ-injected mice, the effects of TS on memory improvement and neuroinflammatory inhibition were confirmed.

Conclusions

TSE disrupted Aβ aggregation, protected neurons against Aβ-induced toxicity, and suppressed neuroinflammation, suggesting that it can suppress the development of AD.

Torreya grandis oil attenuates cognitive impairment in scopolamine-induced mice

The oil of Torreya grandis (TGO), a common nut in China, is considered to be a bioactive edible oil and has a great value in functional food development. In this study, the neuroprotective effects of TGO were investigated on a scopolamine (SCOP)-induced C57BL/6J mouse model. The mice were pretreated with TGO for 30 days (1000 mg per kg per day and 3000 mg per kg per day, i.g.). Behavioral tests showed that the supplementation of TGO could prevent the cognitive deficits induced by SCOP. TGO rebalanced the disorder of the cholinergic system by upgrading the level of acetylcholine. TGO also alleviated the over-activation of microglia and inhibited neuroinflammation and oxidative stress. Additionally, TGO could regulate the composition of gut microbiota, increase the production of short-chain fatty acids, and decrease the content of lipopolysaccharides in the serum. In conclusion, TGO has the potential to prevent loss of memory and impairment of cognition, which may be related to its regulation of the gut microbiota-metabolite-brain axis.

Assessment of Bio-Compounds Content, Antioxidant Activity, and Neuroprotective Effect of Red Cabbage (Brassica oleracea var. Capitata rubra) Processed by Convective Drying at Different Temperatures

Parkinson's disease (PD) is the second most common neurodegenerative disorder, and no efficient therapy able to cure or slow down PD is available. In this study, dehydrated red cabbage was evaluated as a novel source of bio-compounds with neuroprotective capacity. Convective drying was carried out at different temperatures. Total phenolics (TPC), flavonoids (TFC), anthocyanins (TAC), and glucosinolates (TGC) were determined using spectrophotometry, amino acid profile by LC-DAD and fatty acid profile by GC-FID. Phenolic characterization was determined by liquid chromatography-high-resolution mass spectrometry. Cytotoxicity and neuroprotection assays were evaluated in SH-SY5Y human cells, observing the effect on preformed fibrils of α-synuclein. Drying kinetic confirmed a shorter processing time with temperature increase. A high concentration of bio-compounds was observed, especially at 90 °C, with TPC = 1544.04 ± 11.4 mg GAE/100 g, TFC = 690.87 ± 4.0 mg QE/100 g and TGC = 5244.9 ± 260.2 µmol SngE/100 g. TAC degraded with temperature. Glutamic acid and arginine were predominant. Fatty acid profiles were relatively stable and were found to be mostly C18:3n3. The neochlorogenic acid was predominant. The extracts had no cytotoxicity and showed a neuroprotective effect at 24 h testing, which can extend in some cases to 48 h. The present findings underpin the use of red cabbage as a functional food ingredient.

Unveiling the Therapeutic Potentials of Mushroom Bioactive Compounds in Alzheimer's Disease

Alzheimer's disease (AD) stands as a prevailing neurodegenerative condition (NDs), leading to the gradual deterioration of brain cells and subsequent declines in memory, thinking, behavior, and emotion. Despite the intensive research efforts and advances, an effective curative treatment for the disease has not yet been found. Mushrooms, esteemed globally for their exquisite flavors and abundant nutritional benefits, also hold a wealth of health-promoting compounds that contribute to improving AD health. These compounds encompass polysaccharides, proteins, lipids, terpenoids, phenols, and various other bioactive substances. Particularly noteworthy are the potent neuroprotective small molecules found in mushrooms, such as ergothioneine, erinacine, flavonoids, alkaloids, ergosterol, and melanin, which warrant dedicated scrutiny for their therapeutic potential in combating AD. This review summarizes such positive effects of mushroom bioactive compounds on AD, with a hope to contribute to the development of functional foods as an early dietary intervention for this neurodegenerative disease.

Impact of Nut Consumption on Cognition across the Lifespan

Cognitive health is a life-long concern affected by modifiable risk factors, including lifestyle choices, such as dietary intake, with serious implications for quality of life, morbidity, and mortality worldwide. In addition, nuts are a nutrient-dense food that contain a number of potentially neuroprotective components, including monounsaturated and polyunsaturated fatty acids, fiber, B-vitamins, non-sodium minerals, and highly bioactive polyphenols. However, increased nut consumption relates to a lower cardiovascular risk and a lower burden of cardiovascular risk factors that are shared with neurodegenerative disorders, which is why nuts have been hypothesized to be beneficial for brain health. The present narrative review discusses up-to-date epidemiological, clinical trial, and mechanistic evidence of the effect of exposure to nuts on cognitive performance. While limited and inconclusive, available evidence suggests a possible role for nuts in the maintenance of cognitive health and prevention of cognitive decline in individuals across the lifespan, particularly in older adults and those at higher risk. Walnuts, as a rich source of the plant-based polyunsaturated omega-3 fatty acid alpha-linolenic acid, are the nut type most promising for cognitive health. Given the limited definitive evidence available to date, especially regarding cognitive health biomarkers and hard outcomes, future studies are needed to better elucidate the impact of nuts on the maintenance of cognitive health, as well as the prevention and management of cognitive decline and dementia, including Alzheimer disease.

Revisiting the Role of Vitamins and Minerals in Alzheimer's Disease

Alzheimer's disease (AD) is the most common type of dementia that affects millions of individuals worldwide. It is an irreversible neurodegenerative disorder that is characterized by memory loss, impaired learning and thinking, and difficulty in performing regular daily activities. Despite nearly two decades of collective efforts to develop novel medications that can prevent or halt the disease progression, we remain faced with only a few options with limited effectiveness. There has been a recent growth of interest in the role of nutrition in brain health as we begin to gain a better understanding of what and how nutrients affect hormonal and neural actions that not only can lead to typical cardiovascular or metabolic diseases but also an array of neurological and psychiatric disorders. Vitamins and minerals, also known as micronutrients, are elements that are indispensable for functions including nutrient metabolism, immune surveillance, cell development, neurotransmission, and antioxidant and anti-inflammatory properties. In this review, we provide an overview on some of the most common vitamins and minerals and discuss what current studies have revealed on the link between these essential micronutrients and cognitive performance or AD.

Pleiotrophin deficiency protects against high-fat diet-induced neuroinflammation: Implications for brain mitochondrial dysfunction and aberrant protein aggregation

Metabolic Syndrome (MetS) is a risk factor for the development of neurodegenerative diseases. Neuroinflammation associated with MetS may contribute significantly to neurodegeneration. Pleiotrophin (PTN) is a neurotrophic factor that modulates neuroinflammation and is a key player in regulating energy metabolism and thermogenesis, suggesting that PTN could be important in the connection between MetS and neuroinflammation. We have now used a high-fat diet (HFD)-induced obesity model in Ptn^-/- mice. HFD and Ptn deletion caused alterations in circulating hormones including GIP, leptin and resistin. HFD produced in Ptn^+/+ mice a neuroinflammatory state as observed in cerebral quantifications of proinflammatory markers, including Il1β, Tnfα and Ccl2. The upregulation of neuroinflammatory markers was prevented in Ptn^-/- mice. Changes induced by HFD in genes related to mitochondrial biogenesis and dynamics were less pronounced in the brain of Ptn^-/- mice and were accompanied by significant increases in the protein expression of mitochondrial oxidative phosphorylation (OXPHOS) complexes I and IV. HFD-induced changes in genes related to the elimination of protein aggregates were also less pronounced in the brain of Ptn^-/- mice. This study provides substantial evidence that Ptn deletion protects against HFD-induced neuroinflammation, mitochondrial dysfunction, and aberrant protein aggregation, prominent features in neurodegenerative diseases.

The Potential Neuroprotective Effect of Cyperus esculentus L. Extract in Scopolamine-Induced Cognitive Impairment in Rats: Extensive Biological and Metabolomics Approaches

The aim of the present study is to investigate the phytochemical composition of tiger nut (TN) (Cyperus esculentus L.) and its neuroprotective potential in scopolamine (Scop)-induced cognitive impairment in rats. The UHPLC-ESI-QTOF-MS analysis enabled the putative annotation of 88 metabolites, such as saccharides, amino acids, organic acids, fatty acids, phenolic compounds and flavonoids. Treatment with TN extract restored Scop-induced learning and memory impairments. In parallel, TN extract succeeded in lowering amyloid beta, β-secretase protein expression and acetylcholine esterase (AChE) activity in the hippocampus of rats. TN extract decreased malondialdehyde levels, restored antioxidant levels and reduced proinflammatory cytokines as well as the Bax/Bcl2 ratio. Histopathological analysis demonstrated marked neuroprotection in TN-treated groups. In conclusion, the present study reveals that TN extract attenuates Scop-induced memory impairments by diminishing amyloid beta aggregates, as well as its anti-inflammatory, antioxidant, anti-apoptotic and anti-AChE activities.

Chinese herbal formula (GCNY)-medicated serum alleviates peroxidation induced by H2O2 in human microglial cells

Traditional Chinese herbal medicine aiming at nourishing yin formed a distinctive school of thought in history to achieve anti-aging and longevity. In the formula Gancao nourishing yin (GCNY) decoction, all of the ingredients show antioxidant properties. However, in real clinical practice, extractions of herbs are rarely applied alone but are prescribed as the integrated formula. To investigate whether GCNY possesses anti-oxidation potential, we applied GCNY to treat rats to acquire medicated serum, which was then added on H₂O₂ (200 μM)-modeled human microglial cell line HMC-3 in comparison with its control serum. The results revealed that GCNY-medicated serum decreased reactive oxygen species (ROS) levels. Inflammatory cytokines such as pNF-κB p65 (ser536) and IL-6 were also decreased. Nrf2 and its pathway-related molecules, such as HO1, ABCC2, GLCM, ME1, NQO1, and TKT, were activated by H₂O₂ modeling while declined by treating with GCNY-medicated serum, which indicated attenuated oxidative stress of GCNY. Furthermore, mRNA-seq analysis showed 58 differential expressed genes (DEGs), which were enriched in pathways including antigen processing and presentation, longevity regulation, oxidative phosphorylation, and Parkinson’s disease progression. DEGs that were downregulated by H₂O₂ modeling but upregulated by GCNY treatment include CENPF, MKI67, PRR11, and TOP2A. Those targets were reported to be associated with the cell cycle and cell proliferation and belong to the category of growth factor genes. In conclusion, this study verified anti-oxidation effects of GCNY and indicated its promising application for cognitive degeneration and aging-related disorders.

Medha Plus - A novel polyherbal formulation ameliorates cognitive behaviors and disease pathology in models of Alzheimer's disease

Alzheimer's disease (AD) is a multi-faceted neurodegenerative disorder that leads to drastic cognitive impairments culminating in death. Pathologically, it is characterized by amyloid-β (Aβ) plaques, neurofibrillary tangles and neurodegeneration in brain. Complete cure of AD remains elusive to date. Available synthetic drugs only provide symptomatic reliefs targeting single molecule, hence, are unable to address the multi-factorial aspects in AD pathogenesis. It is imperative to develop combinatorial drugs that address the multiple molecular targets in AD. We show a unique polyherbal formulation of Brahmi, Mandukaparni, Shankhpushpi, Yastimadhu, Kokilaksha and Shunthi called 'Medha Plus' (MP), conventionally used for improving memory and reducing anxiety, was able to ameliorate cognitive deficits and associated pathological hallmarks of AD. Viability assays revealed that MP prevented Aβ-induced loss of neurites as well as neuronal apoptosis in cellular models. An array of behavioral studies showed that MP was able to recover AD-associated memory deficits in both Aβ-injected rats and 5XFAD mice. Immunohistochemical studies further revealed that MP treatment reduced Aβ depositshpi and decreased apoptotic cell death in the hippocampus. Enzymatic assays demonstrated anti-oxidative and anti-acetyl cholinesterase properties of MP especially in hippocampus of Aβ-injected rats. An underlying improvement in synaptic plasticity was observed with MP treatment in 5XFAD mice along with an increased expression of phospho-Akt at serine 473 indicating a role of PI3K/Akt signaling in correcting these synaptic deficits. Thus, our strong experiment-driven approach shows that MP is an incredible combinatorial drug that targets multiple molecular targets with exemplary neuroprotective properties and is proposed for clinical trial.

Tau-aggregation inhibition: promising role of nanoencapsulated dietary molecules in the management of Alzheimer's disease

Alzheimer's disease (AD) is a cumulative form of dementia associated with memory loss, cognition impairment, and finally leading to death. AD is characterized by abnormal deposits of extracellular beta-amyloid and intracellular Tau-protein tangles throughout the brain. During pathological conditions of AD, Tau protein undergoes various modifications and aggregates over time. A number of clinical trials on patients with AD symptoms have indicated the effectiveness of Tau-based therapies over anti-Aβ treatments. Thus, there is a huge paradigm shift toward Tau aggregation inhibitors. Several bioactives of plants and microbes have been suggested to cross the neuronal cell membrane and play a crucial role in managing neurodegenerative disorders. Bioactives mainly act as active modulators of AD pathology besides having antioxidant and anti-inflammatory potential. Studies also demonstrated the potential role of dietary molecules in inhibiting the formation of Tau aggregates and removing toxic Tau. Further, these molecules in nonencapsulated form exert enhanced Tau aggregation inhibition activity both in in vitro and in vivo studies suggesting a remarkable role of nanoencapsulation in AD management. The present article aims to review and discuss the structure-function relationship of Tau protein, the post-translational modifications that aid Tau aggregation and potential bioactives that inhibit Tau aggregation.

Z-Guggulsterone attenuates cognitive defects and decreases neuroinflammation in APPswe/PS1dE9 mice through inhibiting the TLR4 signaling pathway

Growing evidence indicates that inflammatory damage is implicated in the pathogenesis of Alzheimer's disease (AD). Z-Guggulsterone (Z-GS) is a natural steroid, which is extracted from Commiphora mukul and has anti-inflammatory effects in vivo and in vitro. In the present study, we investigated the disease-modifying effects of chronic Z-GS administration on the cognitive and neuropathological impairments in the transgenic mouse models of AD. We found that chronic Z-GS administration prevented learning and memory deficits in the APPswe/PS1dE9 mice. In addition, Z-GS treatment significantly decreased cerebral amyloid-β (Aβ) levels and plaque burden via inhibiting amyloid precursor protein (APP) processing by reducing beta-site APP cleaving enzyme 1 (BACE1) expression in the APPswe/PS1dE9 mice. We also found that Z-GS treatment markedly alleviated neuroinflammation and reduced synaptic defects in the APPswe/PS1dE9 mice. Furthermore, the activated TLR4/NF-κB signaling pathways in APPswe/PS1dE9 mice were remarkably inhibited by Z-GS treatment, which was achieved via suppressing the phosphorylation of JNK. Collectively, our data demonstrate that chronic Z-GS treatment restores cognitive defects and reverses multiple neuropathological impairments in the APPswe/PS1dE9 mice. This study provides novel insights into the neuroprotective effects and neurobiological mechanisms of Z-GS on AD, indicating that Z-GS is a promising disease-modifying agent for the treatment of AD.

Pathogenic mechanisms and therapeutic promise of phytochemicals and nanocarriers based drug delivery against radiotherapy-induced neurotoxic manifestations

Radiotherapy is one of the extensively used therapeutic modalities in glioblastoma and other types of cancers. Radiotherapy is either used as a first-line approach or combined with pharmacotherapy or surgery to manage and treat cancer. Although the use of radiotherapy significantly increased the survival time of patients, but its use has been reported with marked neuroinflammation and cognitive dysfunction that eventually reduced the quality of life of patients. Based on the preclinical and clinical investigations, the profound role of increased oxidative stress, nuclear translocation of NF-kB, production of proinflammatory cytokines such as TNF-α, IL-6, IL-β, increased level of MMPs, increased apoptosis, reduced angiogenesis, neurogenesis, and histological aberrations in CA1, CA2, CA3 and DG region of the hippocampus have been reported. Various pharmacotherapeutic drugs are being used as an adjuvant to counteract this neurotoxic manifestation. Still, most of these drugs suffer from systemic adverse effect, causes interference to ongoing chemotherapy, and exhibit pharmacokinetic limitations in crossing the blood-brain barrier. Therefore, various phytoconstituents, their nano carrier-based drug delivery systems and miRNAs have been explored to overcome the aforementioned limitations. The present review is focused on the mechanism and evidence of radiotherapy-induced neuroinflammation and cognitive dysfunction, pathological and molecular changes in the brain homeostasis, available adjuvants, their limitations. Additionally, the potential role and mechanism of neuroprotection of various nanocarrier based natural products and miRNAs have been discussed.

Fatty Acids: An Insight into the Pathogenesis of Neurodegenerative Diseases and Therapeutic Potential

One of the most common lipids in the human body is palmitic acid (PA), a saturated fatty acid with essential functions in brain cells. PA is used by cells as an energy source, besides being a precursor of signaling molecules and protein tilting across the membrane. Although PA plays physiological functions in the brain, its excessive accumulation leads to detrimental effects on brain cells, causing lipotoxicity. This mechanism involves the activation of toll-like receptors (TLR) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathways, with the consequent release of pro-inflammatory cytokines, increased production of reactive oxygen species (ROS), endoplasmic reticulum (ER) stress, and autophagy impairment. Importantly, some of the cellular changes induced by PA lead to an augmented susceptibility to the development of Alzheimer's and Parkinson´s diseases. Considering the complexity of the response to PA and the intrinsic differences of the brain, in this review, we provide an overview of the molecular and cellular effects of PA on different brain cells and their possible relationships with neurodegenerative diseases (NDs). Furthermore, we propose the use of other fatty acids, such as oleic acid or linoleic acid, as potential therapeutic approaches against NDs, as these fatty acids can counteract PA's negative effects on cells.

Effects of Omega-3 Polyunsaturated Fatty Acids on Cognitive Function after Splenectomy in Rats

Background

Postoperative cognitive dysfunction (POCD) is a common complication after abdominal surgery. Several studies have reported that POCD is related to neuroinflammation caused by surgery. Omega-3 polyunsaturated fatty acids (PUFAs) can effectively inhibit the systematic inflammatory response. So, we use fish oil to study the effect of fish oil on inflammation, immunity, and cognitive behavior after splenectomy in rats.

Methods

60 SD (Sprague-Dawley) rats were randomly divided into control group (group C, n = 20), surgery group (group S, n = 20), and omega-3 (fish oil) intervention group (group F, n = 20). Omega-3 PUFA was injected intraperitoneally from 3 days before operation to 7 days after operation in group F, and normal saline was injected simultaneously in group S. Rats in group S and group F received splenectomy under general anesthesia. Morris water maze behavioral evaluation was performed on the first, third, fifth, and seventh day after operation. The levels of IL-1β (interleukin-1β), IL-6 (interleukin-6), TNF-α (tumor necrosis factor-α), SOD (superoxide dismutase), and GSH-PX (glutathione peroxidase) were detected.

Results

Serums IL-1β, IL-6, and TNF-α concentrations in group S and group F were higher than those in group C (P < 0.01), while those inflammatory cytokines in group F were significantly lower than those in group S (P < 0.01); serum GSH-PX levels in group F were higher than group S (P < 0.01). The Morris water maze behavior test performance of group F was better than that of group S (P < 0.05).

Conclusion

Omega-3 PUFA can effectively improve postoperative inflammatory response, reduce the damage of antioxidant defense system, and improve postoperative cognitive function.

Anti-Alzheimer's disease potential of Arabian coffee versus Date palm seed extract in male rats

Coffee is among the most commonly consumed beverage all over the world. Studies have increasingly suggested caffeine and coffee as effective therapeutic interventions against Alzheimer's disease (AD). We have therefore utilized the aluminum chloride rat model for AD to compare the influence of moderately caffeinated (Arabian) and decaffeinated (Date palm seed) coffee on cognitive impairment and pathological events in AD. AD rats given Arabian or Date palm seed coffee were protected against memory impairment and had lower serum levels of the abnormal protein (amyloid-beta; Aβ1-42), the central pathogenic contributor to AD, and transforming growth factor-beta (TGF-β). Interestingly, Date palm seed (decaffeinated) coffee seems to provide more pronounced protection against AD than Arabian (moderately caffeinated) coffee as evidenced by the greater decrease in serum Aβ levels. These results suggest a surprising therapeutic potential of moderate caffeine intake in Arabian coffee to ameliorate AD through decreasing serum Aβ levels. However, Date palm seed (decaffeinated) coffee, rich in flavonoids, appears to provide a better AD-modifying ability through a direct reduction of Aβ production. PRACTICAL APPLICATIONS: Consumption of moderately caffeinated Arabian coffee attenuated AD-induced cognitive impairment via its anti-amyloidogenic potential, decreasing Aβ levels. Moreover, intake of decaffeinated Date seed extract, rich in flavonoids, exerted a superior anti-AD potential through a direct reduction of Aβ production. Both of them were also safe and maintained hepatic and renal functions in a rat model of AlCl₃ -induced AD. Further clinical studies are warranted to confirm current results and to recommend the regular drinking of Arabian coffee or Date seed extract as a protective approach to delay AD progression in vulnerable individuals or in early disease stages.

Cycloastragenol, a Triterpenoid Saponin, Regulates Oxidative Stress, Neurotrophic Dysfunctions, Neuroinflammation and Apoptotic Cell Death in Neurodegenerative Conditions

Here, we have unveiled the effects of cycloastragenol against Aβ (Amyloid-beta)-induced oxidative stress, neurogenic dysfunction, activated mitogen-activated protein (MAP) kinases, and mitochondrial apoptosis in an Aβ-induced mouse model of Alzheimer's disease (AD). The Aβ-induced mouse model was developed by the stereotaxic injection of amyloid-beta (5 μg/mouse/intracerebroventricular), and cycloastragenol was given at a dose of 20 mg/kg/day/p.o for 6 weeks daily. For the biochemical analysis, we used immunofluorescence and Western blotting. Our findings showed that the injection of Aβ elevated oxidative stress and reduced the expression of neurogenic markers, as shown by the reduced expression of brain-derived neurotrophic factor (BDNF) and the phosphorylation of its specific receptor tropomyosin receptor kinase B (p-TrKB). In addition, there was a marked reduction in the expression of NeuN (neuronal nuclear protein) in the Aβ-injected mice brains (cortex and hippocampus). Interestingly, the expression of Nrf2 (nuclear factor erythroid 2-related factor 2), HO-1 (heme oxygenase-1), p-TrKB, BDNF, and NeuN was markedly enhanced in the Aβ + Cycloastragenol co-treated mice brains. We have also evaluated the expressions of MAP kinases such as phospho c-Jun-N-terminal kinase (p-JNK), p-38, and phospho-extracellular signal-related kinase (ERK1/2) in the experimental groups, which suggested that the expression of p-JNK, p-P-38, and p-Erk were significantly upregulated in the Aβ-injected mice brains; interestingly, these markers were downregulated in the Aβ + Cycloastragenol co-treated mice brains. We also checked the expression of activated microglia and inflammatory cytokines, which showed that cycloastragenol reduced the activated microglia and inflammatory cytokines. Moreover, we evaluated the effects of cycloastragenol against mitochondrial apoptosis and memory dysfunctions in the experimental groups. The findings showed significant regulatory effects against apoptosis and memory dysfunction as revealed by the Morris water maze (MWM) test. Collectively, the findings suggested that cycloastragenol regulates oxidative stress, neurotrophic processes, neuroinflammation, apoptotic cell death, and memory impairment in the mouse model of AD.

Neuroprotective Effects against Glutamate-Induced HT-22 Hippocampal Cell Damage and Caenorhabditis elegans Lifespan/Healthspan Enhancing Activity of Auricularia polytricha Mushroom Extracts

Oxidative stress is associated with several diseases, particularly neurodegenerative diseases, commonly found in the elderly. The attenuation of oxidative status is one of the alternatives for neuroprotection and anti-aging. Auricularia polytricha (AP), an edible mushroom, contains many therapeutic properties, including antioxidant properties. Herein, we report the effects of AP extracts on antioxidant, neuroprotective, and anti-aging activities. The neuroprotective effect of AP extracts against glutamate-induced HT-22 neuronal damage was determined by evaluating the cytotoxicity, intracellular reactive oxygen species (ROS) accumulation, and expression of antioxidant enzyme genes. Lifespan and healthspan assays were performed to examine the effects of AP extracts from Caenorhabditis elegans. We found that ethanolic extract (APE) attenuated glutamate-induced HT-22 cytotoxicity and increased the expression of antioxidant enzyme genes. Moreover, APE promoted in the longevity and health of the C. elegans. Chemical analysis of the extracts revealed that APE contains the highest quantity of flavonoids and a reasonable percentage of phenols. The lipophilic compounds in APE were identified by gas chromatography/mass spectrometry (GC/MS), revealing that APE mainly contains linoleic acid. Interestingly, linoleic acid suppressed neuronal toxicity and ROS accumulation from glutamate induction. These results indicate that AP could be an exciting natural source that may potentially serves as neuroprotective and anti-aging agents.

Adult-onset CNS myelin sulfatide deficiency is sufficient to cause Alzheimer's disease-like neuroinflammation and cognitive impairment

BACKGROUND

Human genetic association studies point to immune response and lipid metabolism, in addition to amyloid-beta (Aβ) and tau, as major pathways in Alzheimer's disease (AD) etiology. Accumulating evidence suggests that chronic neuroinflammation, mainly mediated by microglia and astrocytes, plays a causative role in neurodegeneration in AD. Our group and others have reported early and dramatic losses of brain sulfatide in AD cases and animal models that are mediated by ApoE in an isoform-dependent manner and accelerated by Aβ accumulation. To date, it remains unclear if changes in specific brain lipids are sufficient to drive AD-related pathology.

METHODS

To study the consequences of CNS sulfatide deficiency and gain insights into the underlying mechanisms, we developed a novel mouse model of adult-onset myelin sulfatide deficiency, i.e., tamoxifen-inducible myelinating glia-specific cerebroside sulfotransferase (CST) conditional knockout mice (CSTfl/fl/Plp1-CreERT), took advantage of constitutive CST knockout mice (CST-/-), and generated CST/ApoE double knockout mice (CST-/-/ApoE-/-), and assessed these mice using a broad range of methodologies including lipidomics, RNA profiling, behavioral testing, PLX3397-mediated microglia depletion, mass spectrometry (MS) imaging, immunofluorescence, electron microscopy, and Western blot.

RESULTS

We found that mild central nervous system (CNS) sulfatide losses within myelinating cells are sufficient to activate disease-associated microglia and astrocytes, and to increase the expression of AD risk genes (e.g., Apoe, Trem2, Cd33, and Mmp12), as well as previously established causal regulators of the immune/microglia network in late-onset AD (e.g., Tyrobp, Dock, and Fcerg1), leading to chronic AD-like neuroinflammation and mild cognitive impairment. Notably, neuroinflammation and mild cognitive impairment showed gender differences, being more pronounced in females than males. Subsequent mechanistic studies demonstrated that although CNS sulfatide losses led to ApoE upregulation, genetically-induced myelin sulfatide deficiency led to neuroinflammation independently of ApoE. These results, together with our previous studies (sulfatide deficiency in the context of AD is mediated by ApoE and accelerated by Aβ accumulation) placed both Aβ and ApoE upstream of sulfatide deficiency-induced neuroinflammation, and suggested a positive feedback loop where sulfatide losses may be amplified by increased ApoE expression. We also demonstrated that CNS sulfatide deficiency-induced astrogliosis and ApoE upregulation are not secondary to microgliosis, and that astrogliosis and microgliosis seem to be driven by activation of STAT3 and PU.1/Spi1 transcription factors, respectively.

CONCLUSION

Our results strongly suggest that sulfatide deficiency is an important contributor and driver of neuroinflammation and mild cognitive impairment in AD pathology.

Deciphering the Potential Neuroprotective Effects of Luteolin against Aβ1-42-Induced Alzheimer's Disease

The current study was undertaken to unveil the protective effects of Luteolin, a natural flavonoid, against amyloid-beta (Aβ₁–₄₂)-induced neuroinflammation, amyloidogenesis, and synaptic dysfunction in mice. For the development of an AD mouse model, amyloid-beta (Aβ₁–₄₂, 5 μL/5 min/mouse) oligomers were injected intracerebroventricularly (i.c.v.) into mice’s brain by using a stereotaxic frame. After that, the mice were treated with Luteolin for two weeks at a dose of 80 mg/kg/day. To monitor the biochemical changes, we conducted western blotting and immunofluorescence analysis. According to our findings, the infusion of amyloid-beta activated c-Jun N-terminal kinases (p-JNK), p38 mitogen-activated protein kinases, glial fibrillary acidic protein (GFAP), and ionized calcium adaptor molecule 1 (Iba-1) in the cortex and hippocampus of the experimental mice; these changes were significantly inhibited in Aβ₁–₄₂ + Luteolin-treated mice. Likewise, we also checked the expression of inflammatory markers, such as p-nuclear factor-kB p65 (p-NF-kB p65 (Ser536), tissue necrosis factor (TNF-α), and Interleukin1-β (IL-1β), in Aβ₁–₄₂-injected mice brain, which was attenuated in Aβ₁–₄₂ + Luteolin-treated mice brains. Further, we investigated the expression of pro- and anti-apoptotic cell death markers such as Bax, Bcl-2, Caspase-3, and Cox-2, which was significantly reduced in Aβ₁–₄₂ + Lut-treated mice brains compared to the brains of the Aβ-injected group. The results also indicated that with the administration of Aβ₁–₄₂, the expression levels of β-site amyloid precursor protein cleaving enzyme (BACE-1) and amyloid-beta (Aβ₁–₄₂) were significantly enhanced, while they were reduced in Aβ₁–₄₂ + Luteolin-treated mice. We also checked the expression of synaptic markers such as PSD-95 and SNAP-25, which was significantly enhanced in Aβ₁–₄₂ + Lut-treated mice. To unveil the underlying factors responsible for the protective effects of Luteolin against AD, we used a specific JNK inhibitor, which suggested that Luteolin reduced Aβ-associated neuroinflammation and neurodegeneration via inhibition of JNK. Collectively, our results indicate that Luteolin could serve as a novel therapeutic agent against AD-like pathological changes in mice.

Mushroom Species Stereum hirsutum as Natural Source of Phenolics and Fatty Acids as Antioxidants and Acetylcholinesterase Inhibitors

Many lignicolous mushroom species are used as a food supplement and may represent an alternative treatment of Alzheimer's disease (AD). This study aimed to evaluate acetylcholinesterase inhibition (AChEI) of Stereum hirsutum together with antioxidant activity (AO) and cytotoxic activity against HepG2 cells. Different extracts (water, ethanol, methanol, polysaccharide) were analyzed, with respect to their mineral composition and chemical content. Ethanol extract was the most potent in AChEI (98.44 %) and demonstrated cytotoxic activity (91.96 % at 900.00 μg/mL), while the highest AO was demonstrated for polar extracts (methanol and water) as well. These activities may be attributed to determined phenolics (hydroxybenzoic and quinic acid) and fatty acids (FA), while biflavonoid amentoflavone may be responsible for cytotoxic activity. The most prevalent FA was linoleic (40.00 %) and the domination of unsaturated FA (UFA) (71.91 %) over saturated (26.96 %) was observed. This is the first report of AChEI of S. hirsutum extracts and first detection of amentoflavone. Due to high amount of UFA and well-expressed AChEI, this species can be considered as a potent food supplement in the palliative therapy of AD.

Alpha-Linolenic Acid Impedes Cadmium-Induced Oxidative Stress, Neuroinflammation, and Neurodegeneration in Mouse Brain

Alpha-Linolenic acid (ALA), an omega-3 polyunsaturated fatty acid, is extracted from plant sources and has been shown to be one of the anti-inflammatory and antioxidant agents. Herein, we revealed the molecular mechanism underlying the anti-inflammatory and antioxidant potential of (ALA), against cadmium in the adult mouse brain. We evaluated the neuroprotective effect of ALA (60 mg/kg per oral for 6 weeks) against CdCl₂ (5 mg/kg)-induced oxidative stress, neuroinflammation, and neuronal apoptosis. According to our findings, ALA markedly reduced ROS production and nitric oxide synthase 2 (NOS2) and enhanced the expression of nuclear factor-2 erythroid-2 (Nrf-2) and heme oxygenase-1 (HO-1) in mice treated with CdCl₂. Most importantly, the molecular docking study revealed that ALA allosterically decreases the overexpression of c-Jun N-terminal kinase (JNK) activity and inhibited the detrimental effect against CdCl₂. Moreover, ALA suppressed CdCl₂-induced glial fibrillary acidic protein (GFAP), nuclear factor-kappa b (NF-κB), and interleukin-1β (IL-1β) in the mouse brain. Further, we also checked the pro- and anti-apoptotic proteins markers such as Bax, Bcl-2, and caspase-3, which were regulated in the cortex of ALA co-treated mouse brain. Overall, our study suggests that oral administration of ALA can impede oxidative stress, neuroinflammation, and increase neuronal apoptosis in the cortex of Cd-injected mouse brain.

Protective effect of alpha-linoleic acid on Aβ-induced oxidative stress, neuroinflammation, and memory impairment by alteration of α7 nAChR and NMDAR gene expression in the hippocampus of rats

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that affects many older people around the world. Numerous studies are underway to evaluate the protective effects of natural products in AD. Alpha-linoleic acid (ALA) is an essential unsaturated fatty acid that exhibits neuroprotective outcomes in rat models of ischemic stroke and Parkinson's disease. This research aimed to investigate the effect of ALA on oxidative stress, neuroinflammation, neuronal death, and memory deficit induced by amyloid-beta (Aβ) peptide. After intrahippocampal injection of Aβ_1-42, rats received ALA (150 μg/kg, subcutaneously) for 14 consecutive days. ALA decreased the levels of malondialdehyde and nitric oxide, enhanced glutathione content, and increased the activity of catalase in the hippocampus of the rat model of AD. It also reduced the expression of tumor necrosis factor-α, interleukin-1β, interleukin-6, nuclear factor-kappa B, and N-methyl-d-aspartate receptor subunits NR2A and NR2B mRNAs in the hippocampus, prevented the neuronal loss in the CA1 region, and enhanced the expression of α7 nicotinic acetylcholine receptor. In addition, ALA allowed Aβ_1-42-injected rats to spend less time and distance to reach the hidden platform in the Morris water maze test and to swim longer in the target quadrant. We concluded that ALA reduces the biochemical, molecular, histological, and behavioral changes caused by Aβ_1-42 and it may be an effective option for treating AD.

Oral Administration of Gintonin Protects the Brains of Mice against Aβ-Induced Alzheimer Disease Pathology: Antioxidant and Anti-Inflammatory Effects

The study was aimed at analyzing the protective effects of gintonin in an amyloid beta- (Aβ-) induced Alzheimer's disease (AD) mouse model. For the development of the Aβ-induced AD mouse model, the amyloid-β (Aβ 1-42) peptide was stereotaxically injected into the brains of mice. Subsequently, gintonin was administered at a dose of 100 mg/kg/day/per oral (p.o) for four weeks daily, and its effects were evaluated by using western blotting, fluorescence analysis of brain sections, biochemical tests, and memory-related behavioral evaluations. To elucidate the effects of gintonin at the mechanistic level, the activation of endogenous antioxidant mechanisms, as well as the activation of astrocytes, microglia, and proinflammatory mediators such as nuclear factor erythroid 2-related factor 2 (NRF-2) and heme oxygenase-1 (HO-1), was evaluated. In addition, microglial cells (BV-2 cells) were used to analyze the effects of gintonin on microglial activation and signaling mechanisms. Collectively, the results suggested that gintonin reduced elevated oxidative stress by improving the expression of NRF-2 and HO-1 and thereby reducing the generation of reactive oxygen species (ROS) and lipid peroxidation (LPO). Moreover, gintonin significantly suppressed activated microglial cells and inflammatory mediators in the brains of Aβ-injected mice. Our findings also indicated improved synaptic and memory functions in the brains of Aβ-injected mice after treatment with gintonin. These results suggest that gintonin may be effective for relieving AD symptoms by regulating oxidative stress and inflammatory processes in a mouse model of AD. Collectively, the findings of this preclinical study highlight and endorse the potential, multitargeted protective effects of gintonin against AD-associated oxidative damage, neuroinflammation, cognitive impairment, and neurodegeneration.

Nicotinamide Ameliorates Amyloid Beta-Induced Oxidative Stress-Mediated Neuroinflammation and Neurodegeneration in Adult Mouse Brain

Alzheimer’s disease (AD) is the most predominant age-related neurodegenerative disease, pathologically characterized by the accumulation of aggregates of amyloid beta Aβ_1–42 and tau hyperphosphorylation in the brain. It is considered to be the primary cause of cognitive dysfunction. The aggregation of Aβ_1–42 leads to neuronal inflammation and apoptosis. Since vitamins are basic dietary nutrients that organisms need for their growth, survival, and other metabolic functions, in this study, the underlying neuroprotective mechanism of nicotinamide (NAM) Vitamin B3 against Aβ_1–42 -induced neurotoxicity was investigated in mouse brains. Intracerebroventricular (i.c.v.) Aβ_1–42 injection elicited neuronal dysfunctions that led to memory impairment and neurodegeneration in mouse brains. After 24 h after Aβ_1–42 injection, the mice were treated with NAM (250 mg/kg intraperitoneally) for 1 week. For biochemical and Western blot studies, the mice were directly sacrificed, while for confocal and “immunohistochemical staining”, mice were perfused transcardially with 4% paraformaldehyde. Our biochemical, immunofluorescence, and immunohistochemical results showed that NAM can ameliorate neuronal inflammation and apoptosis by reducing oxidative stress through lowering malondialdehyde and 2,7-dichlorofluorescein levels in an Aβ_1–42-injected mouse brains, where the regulation of p-JNK further regulated inflammatory marker proteins (TNF-α, IL-1β, transcription factor NF-kB) and apoptotic marker proteins (Bax, caspase 3, PARP1). Furthermore, NAM + Aβ treatment for 1 week increased the amount of survival neurons and reduced neuronal cell death in Nissl staining. We also analyzed memory dysfunction via behavioral studies and the analysis showed that NAM could prevent Aβ_1–42 -induced memory deficits. Collectively, the results of this study suggest that NAM may be a potential preventive and therapeutic candidate for Aβ_1–42 -induced reactive oxygen species (ROS)-mediated neuroinflammation, neurodegeneration, and neurotoxicity in an adult mouse model.

Phosphoinositides: Roles in the Development of Microglial-Mediated Neuroinflammation and Neurodegeneration

Microglia are increasingly recognized as vital players in the pathology of a variety of neurodegenerative conditions including Alzheimer’s (AD) and Parkinson’s (PD) disease. While microglia have a protective role in the brain, their dysfunction can lead to neuroinflammation and contributes to disease progression. Also, a growing body of literature highlights the seven phosphoinositides, or PIPs, as key players in the regulation of microglial-mediated neuroinflammation. These small signaling lipids are phosphorylated derivates of phosphatidylinositol, are enriched in the brain, and have well-established roles in both homeostasis and disease.Disrupted PIP levels and signaling has been detected in a variety of dementias. Moreover, many known AD disease modifiers identified via genetic studies are expressed in microglia and are involved in phospholipid metabolism. One of these, the enzyme PLCγ2 that hydrolyzes the PIP species PI(4,5)P₂, displays altered expression in AD and PD and is currently being investigated as a potential therapeutic target.Perhaps unsurprisingly, neurodegenerative conditions exhibiting PIP dyshomeostasis also tend to show alterations in aspects of microglial function regulated by these lipids. In particular, phosphoinositides regulate the activities of proteins and enzymes required for endocytosis, toll-like receptor signaling, purinergic signaling, chemotaxis, and migration, all of which are affected in a variety of neurodegenerative conditions. These functions are crucial to allow microglia to adequately survey the brain and respond appropriately to invading pathogens and other abnormalities, including misfolded proteins. AD and PD therapies are being developed to target many of the above pathways, and although not yet investigated, simultaneous PIP manipulation might enhance the beneficial effects observed. Currently, only limited therapeutics are available for dementia, and although these show some benefits for symptom severity and progression, they are far from curative. Given the importance of microglia and PIPs in dementia development, this review summarizes current research and asks whether we can exploit this information to design more targeted, or perhaps combined, dementia therapeutics. More work is needed to fully characterize the pathways discussed in this review, but given the strength of the current literature, insights in this area could be invaluable for the future of neurodegenerative disease research.

Pathology, Risk Factors, and Oxidative Damage Related to Type 2 Diabetes-Mediated Alzheimer's Disease and the Rescuing Effects of the Potent Antioxidant Anthocyanin

The pathology and neurodegeneration in type 2 diabetes- (T2D-) mediated Alzheimer's disease (AD) have been reported in several studies. Despite the lack of information regarding the basic underlying mechanisms involved in the development of T2D-mediated AD, some common features of the two conditions have been reported, such as brain atrophy, reduced cerebral glucose metabolism, and insulin resistance. T2D phenotypes such as glucose dyshomeostasis, insulin resistance, impaired insulin signaling, and systemic inflammatory cytokines have been shown to be involved in the progression of AD pathology by increasing amyloid-beta accumulation, tau hyperphosphorylation, and overall neuroinflammation. Similarly, oxidative stress, mitochondrial dysfunction, and the generation of advanced glycation end products (AGEs) and their receptor (RAGE) as a result of chronic hyperglycemia may serve as critical links between diabetes and AD. The natural dietary polyflavonoid anthocyanin enhances insulin sensitivity, attenuates insulin resistance at the level of the target tissues, inhibits free fatty acid oxidation, and abrogates the release of peripheral inflammatory cytokines in obese (prediabetic) individuals, which are responsible for insulin resistance, systemic hyperglycemia, systemic inflammation, brain metabolism dyshomeostasis, amyloid-beta accumulation, and neuroinflammatory responses. In this review, we have shown that obesity may induce T2D-mediated AD and assessed the recent therapeutic advances, especially the use of anthocyanin, against T2D-mediated AD pathology. Taken together, the findings of current studies may help elucidate a new approach for the prevention and treatment of T2D-mediated AD by using the polyflavonoid anthocyanin.

Fisetin Rescues the Mice Brains Against D-Galactose-Induced Oxidative Stress, Neuroinflammation and Memory Impairment

Herein, we have evaluated the protective potentials of Fisetin against d-galactose-induced oxidative stress, neuroinflammation, and memory impairment in mice. d-galactose (D-gal) causes neurological impairment by inducing reactive oxygen species (ROS), neuroinflammation, and synaptic dysfunction, whereas fisetin (Fis) is a natural flavonoid having potential antioxidant effects, and has been used against different models of neurodegenerative diseases. Here, the normal mice were injected with D-gal (100 mg/kg/day for 60 days) and fisetin (20 mg/kg/day for 30 days). To elucidate the protective effects of fisetin against d-galactose induced oxidative stress-mediated neuroinflammation, we conducted western blotting, biochemical, behavioral, and immunofluorescence analyses. According to our findings, D-gal induced oxidative stress, neuroinflammation, synaptic dysfunctions, and cognitive impairment. Conversely, Fisetin prevented the D-gal-mediated ROS accumulation, by regulating the endogenous anti-oxidant mechanisms, such as Sirt1/Nrf2 signaling, suppressed the activated p-JNK/NF-kB pathway, and its downstream targets, such as inflammatory cytokines. Hence, our results together with the previous reports suggest that Fisetin may be beneficial in age-related neurological disorders.

Poly (ADP-ribose) polymerase-1 as a promising drug target for neurodegenerative diseases

AIMS

Poly (ADP-ribose) polymerase- (PARP)-1 is predominantly triggered by DNA damage. Overexpression of PARP-1 is known for its association with the pathogenesis of several CNS disorders, such as Stroke, Parkinson's disease (PD), Alzheimer's disease (AD), Huntington (HD) and Amyotrophic lateral sclerosis (ALS). NAD+ depletion resulted PARP related cell death only happened when the trial used extreme high oxidization treatment. Inhibition of PARP1/2 may induce replication related cell death due to un-repaired DNA damage. This review has discussed PARP-1 modulated downstream pathways in neurodegeneration and various FDA approved PARP-1 inhibitors.

MATERIALS AND METHODS

A systematic literature review of PubMed, Medline, Bentham, Scopus and EMBASE (Elsevier) databases was carried out to understand the nature of the extensive work done on mechanistic role of Poly (ADP-ribose) polymerase and its inhibition in Neurodegenerative diseases.

KEY FINDINGS

Several researchers have put forward number of potential treatments, of which PARP-1 enzyme has been regarded as a potent target intended for the handling of neurodegenerative ailments. Targeting PARP using its chemical inhibitors in various neurodegenerative may have therapeutic outcomes by reducing neuronal death mediated by PARPi. Numerous PARP-1 inhibitors have been studied in neurodegenerative diseases but they haven't been clinically evaluated.

SIGNIFICANCE

In this review, the pathological role of PARP-1 in various neurodegenerative diseases has been discussed along with the therapeutic role of PARP-1 inhibitors in various neurodegenerative diseases.

A Walnut Diet in Combination with Enriched Environment Improves Cognitive Function and Affects Lipid Metabolites in Brain and Liver of Aged NMRI Mice

This in vivo study aimed to test if a diet enriched with 6% walnuts alone or in combination with physical activity supports healthy ageing by changing the oxylipin profile in brain and liver, improving motor function, cognition, and cerebral mitochondrial function. Female NMRI mice were fed a 6% walnut diet starting at an age of 12 months for 24 weeks. One group was additionally maintained in an enriched environment, one group without intervention served as control. After three months, one additional control group of young mice (3 weeks old) was introduced. Motor and cognitive functions were measured using Open Field, Y-Maze, Rotarod and Passive Avoidance tests. Lipid metabolite profiles were determined using RP-LC-ESI(-)-MS/MS in brain and liver tissues of mice. Cerebral mitochondrial function was characterized by the determination of ATP levels, mitochondrial membrane potential and mitochondrial respiration. Expression of genes involved with mito- and neurogenesis, inflammation, and synaptic plasticity were determined using qRT-PCR. A 6% walnut-enriched diet alone improved spatial memory in a Y-Maze alternation test (p < 0.05) in mice. Additional physical enrichment enhanced the significance, although the overall benefit was virtually identical. Instead, physical enrichment improved motor performance in a Rotarod experiment (p* < 0.05) which was unaffected by walnuts alone. Bioactive oxylipins like hydroxy-polyunsaturated fatty acids (OH-PUFA) derived from linoleic acid (LA) were significantly increased in brain (p** < 0.01) and liver (p*** < 0.0001) compared to control mice, while OH-PUFA of α-linolenic acid (ALA) could only be detected in the brains of mice fed with walnuts. In the brain, walnuts combined with physical activity reduced arachidonic acid (ARA)-based oxylipin levels (p < 0.05). Effects of walnut lipids were not linked to mitochondrial function, as ATP production, mitochondrial membrane potential and mitochondrial respiration were unaffected. Furthermore, common markers for synaptic plasticity and neuronal growth, key genes in the regulation of cytoprotective response to oxidative stress and neuronal growth were unaffected. Taken together, walnuts change the oxylipin profile in liver and brain, which could have beneficial effects for healthy ageing, an effect that can be further enhanced with an active lifestyle. Further studies may focus on specific nutrient lipids that potentially provide preventive effects in the brain.

TLR4 Targeting as a Promising Therapeutic Strategy for Alzheimer Disease Treatment

Alzheimer disease (AD) is a devastating neurodegenerative disorder characterized by extracellular accumulation of amyloid-beta and formation of intracellular neurofibrillary tangles. Microglia activation and neuroinflammation play important roles in the pathogenesis of AD; Toll-like receptor 4 (TLR4)-a key component of the innate immune system-in microglia is also thought to be involved based on the observed association between TLR gene polymorphisms and AD risk. TLR4 has been shown to exert both detrimental and beneficial effects on AD-related pathologies. In preclinical models, experimental manipulations targeting TLR4 were shown to improve learning and memory, which was related to inhibition of pro-inflammatory cytokine release and reduction of oxidative stress. In this review, we summarize the key evidence supporting TLR4 as a promising therapeutic target in AD treatment.

Antioxidant and Neuroprotective Effects of Caffeine against Alzheimer's and Parkinson's Disease: Insight into the Role of Nrf-2 and A2AR Signaling

This paper reviews the results of studies conducted on the role of caffeine in the management of different neurological disorders, such as Parkinson's disease (PD) and Alzheimer's disease (AD). To highlight the potential role of caffeine in managing different neurodegenerative diseases, we identified studies by searching PubMed, Web of Science, and Google Scholar by scrutinizing the lists of pertinent publications. According to the collected overall findings, caffeine may reduce the elevated oxidative stress; inhibit the activation of adenosine A2A, thereby regulating the accumulation of Aβ; reduce the hyperphosphorylation of tau; and reduce the accumulation of misfolded proteins, such as α-synuclein, in Alzheimer's and Parkinson's diseases. The studies have suggested that caffeine has promising protective effects against different neurodegenerative diseases and that these effects may be used to tackle the neurological diseases and/or their consequences. Here, we review the ongoing research on the role of caffeine in the management of different neurodegenerative disorders, focusing on AD and PD. The current findings suggest that caffeine produces potent antioxidant, inflammatory, and anti-apoptotic effects against different models of neurodegenerative disease, including AD, PD, and other neurodegenerative disorders. Caffeine has shown strong antagonistic effects against the adenosine A2A receptor, which is a microglial receptor, and strong agonistic effects against nuclear-related factor-2 (Nrf-2), thereby regulating the cellular homeostasis at the brain by reducing oxidative stress, neuroinflammation, regulating the accumulation of α-synuclein in PD and tau hyperphosphorylation, amyloidogenesis, and synaptic deficits in AD, which are the cardinal features of these neurodegenerative diseases.

Dopamine D1 receptor agonist A-68930 ameliorates Aβ1-42-induced cognitive impairment and neuroinflammation in mice

Alzheimer's disease (AD) is an irreversible neurodegenerative disease characterized by progressive cognitive dysfunction and memory impairment. Dopamine is an important catecholaminergic neurotransmitter that controls movement, reward, motivation, and cognition. Recently, dopamine receptors were reported to regulate immune system in both periphery and central nervous system. However, whether dopamine D1 receptor (DRD1) activation could improve neuroinflammation in AD conditions remains unknown. The present study aimed to investigate the therapeutic effects and underlying mechanisms of a potent and selective DRD1 agonist A-68930 on Aβ_1-42-induced mice. Here we showed that intraperitoneal injection of A-68930 significantly ameliorated Aβ_1-42-induced cognitive dysfunction in mice. Moreover, both in vivo and in vitro data showed that A-68930-induced DRD1 activation significantly inhibited NLRP3 inflammasome-dependent neuroinflammation induced by Aβ_1-42, and this effect may be mediated by the activation of AMPK/autophagy signaling pathway, which enhanced NLRP3 inflammasome degradation and thus decreased the secretion of IL-1β and IL-18. The present study suggests that A-68930-induced DRD1 signaling efficiently alleviates Aβ_1-42-induced cognitive impairment and neuroinflammation in mice and BV2 cells, and DRD1 may become a promising therapeutic target for AD.

Antioxidant and Anti-Inflammatory Effects of Citrus Flavonoid Hesperetin: Special Focus on Neurological Disorders

Neurodegenerative disorders have emerged as a serious health issue in the current era. The most common neurodegenerative disorders are Alzheimer's disease (AD), Parkinson's disease, multiple sclerosis, and amyotrophic lateral sclerosis (ALS). These diseases involve progressive impairment of neurodegeneration and memory impairment. A wide range of compounds have been identified as potential neuroprotective agents against different models of neurodegeneration both in vivo and in vitro. Hesperetin, a flavanone class of citrus flavonoid, is a derivative of hesperidin found in citrus fruits such as oranges, grapes, and lemons. It has been extensively reported that hesperetin exerts neuroprotective effects in experimental models of neurodegenerative diseases. In this systematic review, we have compiled all the studies conducted on hesperetin in both in vivo and in vitro models of neurodegeneration. Here, we have used an approach to lessen the bias in each study, providing a least biased, broad understanding of findings and impartial conclusions of the strength of evidence and the reliability of findings. In this review, we collected different papers from a wide range of journals describing the beneficial effects of hesperetin on animal models of neurodegeneration. Our results demonstrated consistent neuroprotective effects of hesperetin against different models of neurodegeneration. In addition, we have summarized its underlying mechanisms. This study provides the foundations for future studies and recommendations of further mechanistic approaches to conduct preclinical studies on hesperetin in different models.

Torularhodin from Sporidiobolus pararoseus Attenuates d-galactose/AlCl3-Induced Cognitive Impairment, Oxidative Stress, and Neuroinflammation via the Nrf2/NF-κB Pathway

Oxidative stress and neuroinflammation are considered as crucial culprits in Alzheimer's disease (AD). Torularhodin, a carotenoid pigment, possesses powerful antioxidant activity. This study aimed to elucidate the protective effects of torularhodin in the AD-like mouse model and investigated the underlying mechanisms. Behavioral and histopathological results suggested that torularhodin relieved cognitive impairments, attenuated Aβ accumulation, and inhibited glial overactivation in d-gal/AlCl₃-induced ICR mice. Simultaneously, torularhodin also markedly increased antioxidant enzyme capacities, lowered the contents of RAGE, and reduced levels of inflammatory cytokines. Western blot results showed that torularhodin ameliorated neuronal oxidative damage via activation of Nrf2 translocation, upregulation of HO-1, and inactivation of NF-κB in vivo and in vitro. Thus, torularhodin effectively ameliorated cognitive impairment, oxidative stress, and neuroinflammation, possibly through the Nrf2/NF-κB signaling pathways, suggesting torularhodin might offer a promising prevention strategy for neurodegenerative diseases.

Sodium Butyrate Protects N2a Cells against Aβ Toxicity In Vitro

Alzheimer's disease (AD) is a common neurodegenerative disease. Aβ plays an important role in the pathogenesis of AD. Sodium butyrate (NaB) is a short-chain fatty acid salt that exerts neuroprotective effects such as anti-inflammatory, antioxidant, antiapoptotic, and cognitive improvement in central nervous system diseases. The aim of this study is to research the protective effects of NaB on neurons against Aβ toxicity and to uncover the underlying mechanisms. The results showed that 2 mM NaB had a significant improvement effect on Aβ-induced N2a cell injury, by increasing cell viability and reducing ROS to reduce injury. In addition, by acting on the GPR109A receptor, NaB regulates the expression of AD-related genes such as APP, NEP, and BDNF. Therefore, NaB protects N2a cells from Aβ-induced cell damage through activating GPR109A, which provides an innovative idea for the treatment of AD.