Neuro-inflammation and anti-inflammatory treatment options for Alzheimer's disease

Lipopolysaccharide-Induced Microglial Neuroinflammation: Attenuation by FK866

Alleviating microglia-mediated neuroinflammation bears great promise to reduce neurodegeneration. Nicotinamide phosphoribosyltransferase (NAMPT) may exert cytokine-like effect in the brain. However, it remains unclear about role of NAMPT in microglial inflammation. Also, it remains unknown about effect of NAMPT inhibition on microglial inflammation. In the present study, we observed that FK866 (a specific noncompetitive NAMPT inhibitor) dose-dependently inhibited lipopolysaccharide (LPS)-induced proinflammatory mediator (interleukin (IL)-6, IL-1β, inducible nitric oxide synthase, nitric oxide and reactive species) level increase in BV2 microglia cultures. FK866 also significantly inhibited LPS-induced polarization change in microglia. Furthermore, LPS significantly increased NAMPT expression and nuclear factor kappa B (NF-κB) phosphorylation in microglia. FK866 significantly decreased NAMPT expression and NF-κB phosphorylation in LPS-treated microglia. Finally, conditioned medium from microglia cultures co-treated with FK866 and LPS significantly increased SH-SY5Y and PC12 cell viability compared with conditioned medium from microglia cultures treated with LPS alone. Our study strongly indicates that NAMPT may be a promising target for microglia modulation and NAMPT inhibition may attenuate microglial inflammation.

The Role of Chronic Inflammation in Various Diseases and Anti-inflammatory Therapies Containing Natural Products

Chronic inflammation represents a long-term reaction of the body's immune system to noxious stimuli. Such a sustained inflammatory response sometimes results in lasting damage to healthy tissues and organs. In fact, chronic inflammation is implicated in the development and progression of various diseases, including cardiovascular diseases, respiratory diseases, metabolic diseases, neurodegenerative diseases, and even cancers. Targeting nonresolving inflammation thus provides new opportunities for treating relevant diseases. In this review, we will go over several chronic inflammation-associated diseases first with emphasis on the role of inflammation in their pathogenesis. Then, we will summarize a number of natural products that exhibit therapeutic effects against those diseases by acting on different markers in the inflammatory response. We envision that natural products will remain a rich resource for the discovery of new drugs treating diseases associated with chronic inflammation.

Chemical Constituents and their Antioxidant, Anti-Inflammatory and Anti-Acetylcholinesterase Activities from Pholidota cantonensis

Alzheimer's disease (AD) has the third highest health expenditures after heart disease and cancer. It has emerged as a serious global health issue. The discovery of new drugs to prevent and treat AD is of utmost importance. Pholidota cantonensis is an edible medicinal plant consumed in China. It is widely used in traditional Chinese medicine to treat various diseases. P. cantonensis has been reported to have antioxidant, anti-inflammatory, antitumor and antibacterial activities. Among these properties, its potent antioxidant activity has attracted our attention, since oxidative stress is one of the important pathological mechanisms involved in AD. This study aimed to isolate the compounds from the active extract and evaluate their bioactivities. Fifteen compounds, including one new compound, were obtained. The isolates were tested for 2,2'-diphenyl-1-picrylhydrazyl (DPPH)/2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities, anti-acetylcholinesterase (anti-AChE) activities and inhibitory effects on nitrogen monoxide (NO) release in the BV-2 cells. Compounds 1, 2, 4, 6, 8, and 13-15 exhibited two kinds of AD-associated bioactivities. More importantly, compound 13 showed more potent NO inhibitory activity (IC₅₀ = 0.72 ± 0.08 μM) than the positive control quercetin (IC₅₀ = 12.94 ± 0.08 μM). Compound 13 also had a higher inhibitory rate (99.59 ± 0.43%) on AChE than that of the positive control galantamine (78.32 ± 1.16%) at the concentrate of 50 μg/mL. Our studies provide new insights into this plant in terms of its potential in the development of new multi-target anti-Alzheimer's disease (anti-AD) drugs.

Alzheimer's Disease and Diabetes: Role of Diet, Microbiota and Inflammation in Preclinical Models

Alzheimer's disease (AD) is the most common cause of dementia. Epidemiological studies show the association between AD and type 2 diabetes (T2DM), although the mechanisms are not fully understood. Dietary habits and lifestyle, that are risk factors in both diseases, strongly modulate gut microbiota composition. Also, the brain-gut axis plays a relevant role in AD, diabetes and inflammation, through products of bacterial metabolism, like short-chain fatty acids. We provide a comprehensive review of current literature on the relation between dysbiosis, altered inflammatory cytokines profile and microglia in preclinical models of AD, T2DM and models that reproduce both diseases as commonly observed in the clinic. Increased proinflammatory cytokines, such as IL-1β and TNF-α, are widely detected. Microbiome analysis shows alterations in Actinobacteria, Bacteroidetes or Firmicutes phyla, among others. Altered α- and β-diversity is observed in mice depending on genotype, gender and age; therefore, alterations in bacteria taxa highly depend on the models and approaches. We also review the use of pre- and probiotic supplements, that by favoring a healthy microbiome ameliorate AD and T2DM pathologies. Whereas extensive studies have been carried out, further research would be necessary to fully understand the relation between diet, microbiome and inflammation in AD and T2DM.

Neurological features and outcome in COVID-19: dementia can predict severe disease

The COVID-19 pandemic has infected more than 22 million people worldwide. Although much has been learned about COVID-19, we do not know much about its neurological features and their outcome. This observational study was conducted on the patients of Imam Hossein Hospital, and 361 adult patients (214 males) with confirmed diagnosis of COVID-19 from March 5, 2020 to April 3, 2020, were enrolled. Data was gathered on age, sex, comorbidities, initial symptoms, symptoms during the disease course, neurological symptoms, and outcome. The mean age of the patients was 61.90 ± 16.76 years. The most common initial symptoms were cough, fever, and dyspnea. In 21 patients (5.8%), the initial symptom was neurological. History of dementia was associated with severe COVID-19 disease (odds ratio = 1.28). During the course of the disease, 186 patients (51.52%) had at least one neurological symptom, the most common being headache (109 [30.2%]), followed by anosmia/ageusia (69, [19.1%]), and dizziness (54, [15%]). Also, 31 patients had neurological complications (8.58%). Anosmia, ageusia, dizziness, and headache were associated with favorable outcome (P < 0.001), while altered mental status and hemiparesis were associated with poor outcome. The mortality rate of patients who had neurological complications was more than twice than that of patients without neurological complication (P = 0.008). Almost half of the patients experienced at least one neurological symptom, which may be the initial presentation of COVID-19. Dementia appears to be associated with severe COVID-19. Mortality was higher in patients with neurological complications, and these patients needed more intensive care.

Crosstalk between Depression and Dementia with Resting-State fMRI Studies and Its Relationship with Cognitive Functioning

Alzheimer’s disease (AD) is the most common type of dementia, and depression is a risk factor for developing AD. Epidemiological studies provide a clinical correlation between late-life depression (LLD) and AD. Depression patients generally remit with no residual symptoms, but LLD patients demonstrate residual cognitive impairment. Due to the lack of effective treatments, understanding how risk factors affect the course of AD is essential to manage AD. Advances in neuroimaging, including resting-state functional MRI (fMRI), have been used to address neural systems that contribute to clinical symptoms and functional changes across various psychiatric disorders. Resting-state fMRI studies have contributed to understanding each of the two diseases, but the link between LLD and AD has not been fully elucidated. This review focuses on three crucial and well-established networks in AD and LLD and discusses the impacts on cognitive decline, clinical symptoms, and prognosis. Three networks are the (1) default mode network, (2) executive control network, and (3) salience network. The multiple properties emphasized here, relevant for the hypothesis of the linkage between LLD and AD, will be further developed by ongoing future studies.

L-Type Amino Acid Transporter 1 Enables the Efficient Brain Delivery of Small-Sized Prodrug across the Blood-Brain Barrier and into Human and Mouse Brain Parenchymal Cells

Membrane transporters have long been utilized to improve the oral, hepatic, and renal (re)absorption. In the brain, however, the transporter-mediated drug delivery has not yet been fully achieved due to the complexity of the blood-brain barrier (BBB). Because L-type amino acid transporter 1 (LAT1) is a good candidate to improve the brain delivery, we developed here four novel LAT1-utilizing prodrugs of four nonsteroidal anti-inflammatory drugs. As a result, all the prodrugs were able to cross the BBB and localize into the brain cells. The brain uptake of salicylic acid (SA) was improved five times, not only across the mouse BBB but also into the cultured mouse and human brain cells. The naproxen prodrug was also transported efficiently into the mouse brain achieving less peripheral exposure, but the brain release of naproxen from the prodrug was not improved. Contrarily, the high plasma protein binding of the flurbiprofen prodrug and the premature bioconversion of the ibuprofen prodrug in the mouse blood hindered the efficient brain delivery. Thus, the structure of the parent drug affects the successful brain delivery of the LAT1-utilizing prodrugs, and the small-sized LAT1-utilizing prodrug of SA constituted a successful model to specifically deliver its parent drug across the mouse BBB and into the cultured mouse and human brain cells.

Repurposing drugs to fight aging: The difficult path from bench to bedside

The steady rise in life expectancy occurred across all developed countries during the last century. This demographic trend is, however, not accompanied by the same healthspan extension. This is since aging is the main risk factor for all age-associated pathological conditions. Therefore, slowing the rate of aging is suggested to be more efficient in preventing or delaying age-related diseases than treat them one by one, which is the common approach in a current pharmacological disease-oriented paradigm. To date, a variety of medications designed to treat particular pathological conditions have been shown to exhibit pro-longevity effects in different experimental models. Among them, there are many commonly used prescription and over-the-counter pharmaceuticals such as metformin, rapamycin, aspirin, statins, melatonin, vitamin antioxidants, etc. All of them are being increasingly investigated in preclinical and clinical trials with the aim of determine whether they have potential for extension of human healthspan. The results from these trials are frequently inconclusive and fall short of initial expectations, suggesting that innovative research ideas and additional translational steps are required to overcome obstacles for implementation of such approaches in clinical practice. In this review, recent advances and challenges in the field of repurposing widely used conventional pharmaceuticals to target the aging process are summarized and discussed.

The Association between the Usage of Non-Steroidal Anti-Inflammatory Drugs and Cognitive Status: Analysis of Longitudinal and Cross-Sectional Studies from the Global Alzheimer's Association Interactive Network and Transcriptomic Data

The degenerative cognitive and physical decline of Alzheimer patients, coupled with the extensive psychological and economic tolls imposed on family members that serve as caretakers, necessitate the discovery of effective cures and preventative measures for age-related cognitive depreciation. In the journey of Alzheimer’s disease treatment discovery, several cross-sectional and longitudinal studies have delineated a noticeable association between the use of nonsteroidal anti-inflammatory drugs (NSAIDs), a class of low-cost drugs with minimal side effects, and the alleviation of age-related memory impairment. In this study, four datasets (two cross-sectional and two longitudinal studies) derived from the Global Alzheimer’s Association Interactive Network (GAAIN) were analyzed. The significant association between the usage of NSAIDs and better cognitive status was observed. The results agree with the findings of previous studies that the use of NSAIDs may be beneficial in the early stages of Alzheimer’s disease. Transcriptomic data show that ibuprofen treatment results in upregulation of several genes involved in arachidonic acid metabolism including PPARγ, Cyp4a12b, Cyp2c66, and Cyp2c37 in the hippocampus. The increase in conversion of arachidonic acid into anti-inflammatory 16C and 18C dicarboxylic acids as well as epoxyeicosatrienoic acids may play a role in reducing the risk of Alzheimer’s disease development.

Extract of the Aerial Part of Polygala tenuifolia Attenuates d-Galactose/NaNO2-induced Learning and Memory Impairment in Mice

Alzheimer's disease, one of the most common types of age-related dementia, is characterized by memory deterioration and behavior disorder. The aboveground part of Polygala tenuifolia is a traditional Chinese medicine used for the treatment of amnesia. This study was conducted to investigate the ameliorating effect of the aerial part of P. tenuifolia on d-galactose/NaNO₂-induced learning and memory impairment in mice. d-galactose (120 mg/kg) and NaNO₂ (90 mg/kg) were injected intraperitoneally for 60 days to induce learning and memory impairment in mice. The aerial part of P. tenuifolia (25, 50, and 100 mg/kg) and piracetam (200 mg/kg) were simultaneously administered orally on days 15 - 60. Results of this study showed that aerial part of P. tenuifolia significantly decreased the latency time and increased the number of platform crossings in the Morris water maze compared with the Model group. Moreover, the aerial part of P. tenuifolia significantly increased the latency time and decreased the error frequency in the step-down and step-through tests compared with the Model group. Meanwhile, the aerial part of P. tenuifolia was able to regulate the cholinergic system by increasing the levels of ACh and ChAT and decreasing the level of AChe. The aerial part of P. tenuifolia also significantly attenuated the levels of interleukin-1 beta and malonaldehyde and enhanced the interleukin-10 and glutathione levels and superoxide dismutase activity. Furthermore, treatment with aerial part of P. tenuifolia increased the protein and mRNA expression of brain-derived neurotrophic factor and tropomyosin receptor kinase B in the hippocampus. These results suggest that the aerial part of P. tenuifolia can ameliorate learning and memory impairments by modulating cholinergic activity, inhibiting neuroinflammation and oxidative stress, and regulating the brain-derived neurotrophic factor and tropomyosin receptor kinase B signaling pathway.

A Perspective on Roles Played by Immunosenescence in the Pathobiology of Alzheimer's Disease

Alzheimer's disease (AD) is a chronic progressive neurodegenerative disorder. Aging is the most significant risk factor for late-onset AD. The age-associated changes in the immune system are termed immunosenescence. A close connection between immunosenescence and AD is increasingly recognized. This article provides an overview of immunosenescence and evidence for its role in the pathogenesis of AD and possible mechanisms as well as the outlook for drug development.

Novel N-benzylpiperidine derivatives of 5-arylisoxazole-3-carboxamides as anti-Alzheimer's agents

The complex pathophysiology of Alzheimer's disease (AD) has prompted researchers to develop multitarget-directed molecules to find an effective therapy against the disease. In this context, a novel series of N-(1-benzylpiperidin-4-yl)-5-arylisoxazole-3-carboxamide derivatives were designed, synthesized, and evaluated against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). In vitro biological evaluation demonstrated that compound 4e was the best AChE (IC₅₀  = 16.07 μM) and BuChE inhibitor (IC₅₀  = 15.16 μM). A kinetic study of 4e was also conducted, which presented a mixed-type inhibition for both enzymes. Molecular docking studies revealed that compound 4e fitted well into the active sites of AChE and BuChE, forming stable and strong interactions with key residues Glu199, Trp84, Asp72, Tyr121, and Phe288 in AChE and His438, Trp82, Ala328, Tyr332, Phe329, Thr120, and Pro285 in BuChE. Besides, the inhibition of BACE1 by 4e and the biometal chelation activity of 4e were measured. The neuroprotective assessment revealed that 4e exhibited 23.2% protection at 50 µM toward amyloid-beta-induced PC12 neuronal cells. Overall, this study exhibited that compound 4e was a promising compound targeting multiple factors associated with AD.

Current Aspects of the Endocannabinoid System and Targeted THC and CBD Phytocannabinoids as Potential Therapeutics for Parkinson's and Alzheimer's Diseases: a Review

Neurodegeneration leading to Parkinson's disease (PD) and Alzheimer's disease (AD) has become a major health burden globally. Current treatments mainly target controlling symptoms and there are no therapeutics available in clinical practice to preventing the neurodegeneration or inducing neuronal repairing. Thus, the demand of novel research for the two disorders is imperative. This literature review aims to provide a collection of published work on PD and AD and current uses of endocannabinoid system (ECS) as a potential drug target for neurodegeneration. PD is frequently treated with L-DOPA and deep brain stimulation. Recent gene modification and remodelling techniques, such as CRISPR through human embryonic stem cells and induced pluripotent stem cells, have shown promising strategy for personalised medicine. AD characterised by extracellular deposits of amyloid β-senile plaques and neurofibrillary tangles of tau protein commonly uses choline acetyltransferase enhancers as therapeutics. The ECS is currently being studied as PD and AD drug targets where overexpression of ECS receptors exerted neuroprotection against PD and reduced neuroinflammation in AD. The delta-9-tetrahydrocannabinoid (Δ9-THC) and cannabidiol (CBD) cannabinoids of plant Cannabis sativa have shown neuroprotection upon PD and AD animal models yet triggered toxic effects on patients when administered directly. Therefore, understanding the precise molecular cascade following cannabinoid treatment is suggested, focusing especially on gene expression to identify drug targets for preventing and repairing neurodegeneration.

Forsythoside B attenuates memory impairment and neuroinflammation via inhibition on NF-κB signaling in Alzheimer's disease

Background

Neuroinflammation is a principal element in Alzheimer’s disease (AD) pathogenesis, so anti-inflammation may be a promising therapeutic strategy. Forsythoside B (FTS•B), a phenylethanoid glycoside isolated from Forsythiae fructus, has been reported to exert anti-inflammatory effects. However, no studies have reported whether the anti-inflammatory properties of FTS•B have a neuroprotective effect in AD. In the present study, these effects of FTS•B were investigated using amyloid precursor protein/presenilin 1 (APP/PS1) mice, BV-2 cells, and HT22 cells.

Methods

APP/PS1 mice were administered FTS•B intragastrically for 36 days. Behavioral tests were then carried out to examine cognitive functions, including the Morris water maze, Y maze, and open field experiment. Immunohistochemistry was used to analyze the deposition of amyloid-beta (Aβ), the phosphorylation of tau protein, and the levels of 4-hydroxynonenal, glial fibrillary acidic protein, and ionized calcium-binding adapter molecule 1 in the hippocampus. Proteins that showed marked changes in levels related to neuroinflammation were identified using proteomics and verified using enzyme-linked immunosorbent assay and western blot. BV-2 and HT22 cells were also used to confirm the anti-neuroinflammatory effects of FTS•B.

Results

In APP/PS1 mice, FTS•B counteracted cognitive decline, ameliorated the deposition of Aβ and the phosphorylation of tau protein, and attenuated the activation of microglia and astrocytes in the cortex and hippocampus. FTS•B affected vital signaling, particularly by decreasing the activation of JNK-interacting protein 3/C-Jun NH2-terminal kinase and suppressing WD-repeat and FYVE-domain-containing protein 1/toll-like receptor 3 (WDFY1/TLR3), further suppressing the activation of nuclear factor-κB (NF-κB) signaling. In BV-2 and HT22 cells, FTS•B prevented lipopolysaccharide-induced neuroinflammation and reduced the microglia-mediated neurotoxicity.

Conclusions

FTS•B effectively counteracted cognitive decline by regulating neuroinflammation via NF-κB signaling in APP/PS1 mice, providing preliminary experimental evidence that FTS•B is a promising therapeutic agent in AD treatment.

Neuroprotective effects of the aerial parts of Polygala tenuifolia Willd extract on scopolamine-induced learning and memory impairments in mice

Alzheimer's disease is a common neurodegenerative disease characterized by progressive cognitive dysfunction and behavioral impairment. Aerial parts of Polygala tenuifolia Willd (APT) is a traditional Chinese medicine used for the treatment of amnesia. The present study aimed to investigate the protective effects of APT on scopolamine-induced learning and memory impairments in mice. Scopolamine-induced mice were used to determine the effects of APT on learning and memory impairment. Mice were orally administered with APT (25, 50 and 100 mg/kg) and piracetam (750 mg/kg) for 14 days, and intraperitoneally injected with scopolamine (2 mg/kg) from days 8 to 14. Morris water maze and step-down tests were performed to evaluate learning and memory. Levels of acetylcholine (ACh), choline acetyltransferase (ChAT), acetylcholinesterase (AChE), interleukin (IL)-1β, IL-10 and brain-derived neurotrophic factor (BDNF) in the hippocampus and frontal cortex were measured by ELISA. Superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione (GSH) were measured via biochemical detection. The results demonstrated that APT ameliorated learning and memory impairment in scopolamine-induced mice. Correspondingly, APT significantly increased ACh and ChAT levels in the hippocampus and prefrontal cortex of scopolamine-induced mice. Additionally, treatment with APT significantly increased BDNF and IL-10 levels, and decreased IL-1β and AChE levels in the same mice. Furthermore, APT significantly increased SOD activity and GSH content, and decreased MDA levels in brain tissue. These results indicated that APT may ameliorate learning and memory impairment by regulating cholinergic activity, promoting BDNF and inhibiting neuroinflammation and oxidative stress.

Alzheimer's Disease and Specialized Pro-Resolving Lipid Mediators: Do MaR1, RvD1, and NPD1 Show Promise for Prevention and Treatment?

Alzheimer's disease (AD) is a common neurodegenerative disease and a major contributor to progressive cognitive impairment in an aging society. As the pathophysiology of AD involves chronic neuroinflammation, the resolution of inflammation and the group of lipid mediators that actively regulate it-i.e., specialized pro-resolving lipid mediators (SPMs)-attracted attention in recent years as therapeutic targets. This review focuses on the following three specific SPMs and summarizes their relationships to AD, as they were shown to effectively address and reduce the risk of AD-related neuroinflammation: maresin 1 (MaR1), resolvin D1 (RvD1), and neuroprotectin D1 (NPD1). These three SPMs are metabolites of docosahexaenoic acid (DHA), which is contained in fish oils and is thus easily available to the public. They are expected to become incorporated into promising avenues for preventing and treating AD in the future.

Lychee seed polyphenol inhibits Aβ-induced activation of NLRP3 inflammasome via the LRP1/AMPK mediated autophagy induction

Emerging evidence indicates that the enhancement of microglial autophagy inhibits the NLRP3 inflammasome mediated neuroinflammation in Alzheimer's disease (AD). Meanwhile, low density lipoprotein receptor-related protein 1 (LRP1) highly expressed in microglia is able to negatively regulate neuroinflammation and positively regulate autophagy. In addition, we have previously reported that an active lychee seed fraction enriching polyphenol (LSP) exhibits anti-neuroinflammation in Aβ-induced BV-2 cells. However, its molecular mechanism of action is still unclear. In this study, we aim to investigate whether LSP inhibits the NLRP3 inflammasome mediated neuroinflammation and clarify its molecular mechanism in Aβ-induced BV-2 cells and APP/PS1 mice. The results showed that LSP dose- and time-dependently activated autophagy by increasing the expression of Beclin 1 and LC3II in BV-2 cells, which was regulated by the upregulation of LRP1 and its mediated AMPK signaling pathway. In addition, both the Western blotting and fluorescence microscopic results demonstrated that LSP could significantly suppress the activation of NLRP3 inflammasome by inhibiting the expression of NLRP3, ASC, the cleavage of caspase-1, and the release of IL-1β in Aβ(1-42)-induced BV-2 cells. In addition, the siRNA LRP1 successfully abolished the effect of LSP on the activation of AMPK and its mediated autophagy, as well as the inhibition of NLRP3 inflammasome. Furthermore, LSP rescued PC-12 cells which were induced by the conditioned medium from Aβ(1-42)-treated BV-2 cells. Moreover, LSP improved the cognitive function and inhibited the NLRP3 inflammasome in APP/PS1 mice. Taken together, LSP inhibited the NLRP3 inflammasome-mediated neuroinflammation in the in vitro and in vivo models of AD, which was closely associated with the LRP1/AMPK-mediated autophagy. Thus, the findings from this study further provide evidences for LSP serving as a potential drug for the treatment of AD in the future.

Beta-amyloid activates NLRP3 inflammasome via TLR4 in mouse microglia

Beta-amyloid(Aβ)-induced inflammation plays a critical role in the pathogenesis of Alzheimer's disease (AD). Nod-like receptor nucleotide-binding domain leucine rich repeat containing protein 3 (NLRP3) inflammasome is involved in the Aβ-induced inflammation. However, the mechanisms by which extracellular Aβ activates cytoplasmic NLRP3 inflammasome are poorly understood. Toll-like receptor 4(TLR4) acts as a sensor of Aβ and performs a key role in neuroinflammation. TLR4 is involved in activating the NLRP3 inflammasome in several diseases. In this study, the interaction between TLR4 and NLRP3 inflammasome in Aβ_1-42-induced neuroinflammation was investigated. BV-2 microglia and primary microglia were primed with lipopolysaccharide (LPS) and then pretreated with TLR4 inhibitor CLI-095, followed by stimulation with Aβ_1-42. The protein expression of NLRP3, the adaptor protein apoptosis-associated speck-like protein containing a CARD (ASC), and caspase-1 p 10 was detected by western blotting and immunostaining. The mRNA expression of inflammatory factors was measured by real-time PCR. The protein level of pro IL-1β and IL-1β was examined by ELISA. Activated microglia were examined by immunofluorescence staining for ionized calcium-binding adapter molecule-1 (Iba-1). Conditioned medium of BV-2 cells was collected to challenge HT-22 neurons. Cell viability was assessed with MTT assay. Assessment of HT-22 cell apoptosis was performed by Annexin V/PI staining and western blotting to detect the protein level of cleaved caspase 3. The results showed that Aβ_1-42 activated and up-regulated the expression of NLRP3 inflammasome in BV-2 microglia, as indicated by increased activation of caspase-1 and secretion of IL-1β. Pharmacological inhibition of TLR4 by CLI-095 abolished Aβ_1-42-induced NLRP3 inflammasome activation, which curbed the development of inflammation and exerted protective effect on HT-22 neurons. Furthermore, the inhibitory effects of CLI-095 on Aβ_1-42-induced inflammation were reversed by NLRP3 activator ATP. Overall, our findings suggested TLR4 mediated Aβ_1-42-induced NLRP3 inflammasome activation in mouse microglia. TLR4/NLRP3 pathway plays a critical role in Aβ_1-42-induced neuroinflammation.

Subchronic administration of auranofin reduced amyloid-β plaque pathology in a transgenic APPNL-G-F/NL-G-F mouse model

Alzheimer's disease (AD) is the most common cause of dementia. Neuropathological processes, including the accumulation of amyloid-β (Aβ) plaques and neurofibrillary tangles, and neuroinflammation, lead to cognitive impairment at middle and eventually later stages of AD progression. Over the last decade, focused efforts have explored repurposed drug approaches for AD pathophysiological mechanisms. Recently, auranofin, an anti-inflammatory drug, was shown to have therapeutic potential in a number of diseases in addition to rheumatoid arthritis. Surprisingly, no data regarding the effects of auranofin on cognitive deficits in AD mice or the influence of auranofin on Aβ pathology and neuroinflammatory processes are available. In the present study, we used 14-month-old transgenic male APP^{NL-G-F/NL-G-F} mice to assess the effects of subchronic administration of auranofin at low doses (1 and 5 mg/kg, intraperitoneal) on spatial memory, Aβ pathology and the expression of cortical and hippocampal proteins (glial fibrillary acidic protein (GFAP), ionized calcium binding adaptor molecule-1 (Iba-1)) and proteins related to synaptic plasticity (glutamic acid decarboxylase 67 (GAD67), homer proteins homologue-1 (Homer-1)). The data demonstrated that auranofin significantly decreased Aβ deposition in the hippocampus and the number of Aβ plaques in the cingulate cortex, but it did not have memory-enhancing effects or induce changes in the expression of the studied proteins. Our current results highlight the importance of considering further pre-clinical research to investigate the possible beneficial effects of auranofin on the other pathological aspects of AD.

Naringenin alleviates cognition deficits in high-fat diet-fed SAMP8 mice

Naringenin is a natural dihydro flavonoid that is abundant in grapefruit. Previous studies suggested the cognition protective effect of naringenin in various cognitive deficits models, such as type 2 diabetic rat model and chemicals (e.g., lipopolysaccharide, scopolamine) treated rodents. However, the effects of naringenin on aging animals and the potential mechanisms are still unclear. In this study, we investigated the influence of naringenin administration on learning deficits in aging mice. High-fat diet-fed SAMP8 mice were employed as an age-related model of Alzheimer's disease. Dietary administration of 0.2% naringenin for 12 weeks significantly improved the spatial learning and memory performance of the high-fat diet-fed SAMP8 mice in both Barnes Maze test and Morris Water Maze test. Further mechanism research indicated that naringenin reduced Aβ production, tau-hyperphosphorylation, oxidative stress, and neuroinflammation in the brain. This research provides further evidence for the treatment effect of naringenin on Alzheimer's disease. PRACTICAL APPLICATIONS: Naringenin, also known as 4',5,7-thrihydroxyflflavanone, is a natural dihydro flavonoid that is abundant in grapefruit and other citrus fruits. The current study first demonstrated the improvement effect of naringenin on cognition deficits in HFD-fed SAMP8 mice, an aging mouse model. Potential mechanisms were also systematically explained by exploring the amyloid-β (Aβ) accumulation, tau hyperphosphorylation, oxidative stress, and neuroinflammation in the brain of mice. This study provides further evidence for the utilization of naringenin as an effective treatment agent for Alzheimer's disease.

Cellular mechanisms and treatments for chemobrain: insight from aging and neurodegenerative diseases

Chemotherapy is a life-saving treatment for cancer patients, but also causes long-term cognitive impairment, or "chemobrain", in survivors. However, several challenges, including imprecise diagnosis criteria, multiple confounding factors, and unclear and heterogeneous molecular mechanisms, impede effective investigation of preventions and treatments for chemobrain. With the rapid increase in the number of cancer survivors, chemobrain is an urgent but unmet clinical need. Here, we leverage the extensive knowledge in various fields of neuroscience to gain insights into the mechanisms for chemobrain. We start by outlining why the post-mitotic adult brain is particularly vulnerable to chemotherapy. Next, through drawing comparisons with normal aging, Alzheimer's disease, and traumatic brain injury, we identify universal cellular mechanisms that may underlie the cognitive deficits in chemobrain. We further identify existing neurological drugs targeting these cellular mechanisms that can be repurposed as treatments for chemobrain, some of which were already shown to be effective in animal models. Finally, we briefly describe future steps to further advance our understanding of chemobrain and facilitate the development of effective preventions and treatments.

Effect of C-phycocyanin on HDAC3 and miRNA-335 in Alzheimer's disease

BACKGROUND

Amyloid-beta (Aβ) plaque deposits and neurofibrillary tangles containing tau proteins are the key pathognomonic manifestations of Alzheimer's disease (AD). Lack of holistic drugs for AD has reinvigorated enthusiasm in the natural product-based therapies. In this study, our idea to decipher the beneficial effects of C-phycocyanin (CPC) in the management of AD is buoyed by its multifaceted and holistic therapeutic effects.

METHODS

We evaluated the effect of CPC treatment on epigenetic factors and inflammatory mediators in a mouse with oligomeric Aβ1-42-induced AD. Besides, the cognitive function was evaluated by the spatial memory performance on a radial arm maze.

RESULTS

The results showed cognitive deficit in the mice with AD along with upregulated HDAC3 expression and diminished miRNA-335 and brain-derived neurotrophic factor (BDNF) expressions. In addition, inflammation was provoked (manifested by increased interleukins (IL)-6 and IL-1β) and neuronal apoptosis was accelerated (indicated by increased Bax, caspase-3, and caspase-9 along with decreased Bcl2) in the hippocampus of the mice with AD. Interestingly, CPC treatment in the mice with AD improved spatial memory performance and decreased the perturbations in the epigenetic and inflammatory biofactors.

CONCLUSION

These results underscore that mitigation of inflammation via regulation of epigenetic factors might be the key pathway underlying the ameliorative effect of CPC against the aberrations in AD. Our findings provide the rationale for considering CPC as a viable therapeutic option in the management of AD.

Systems Pharmacology Approach to Investigate the Mechanism of Kai-Xin-San in Alzheimer's Disease

Alzheimer's disease (AD) is a complex neurodegenerative disease characterized by cognitive dysfunction. Kai-Xin-San (KXS) is a traditional Chinese medicine (TCM) formula that has been used to treat AD patients for over a thousand years in China. However, the therapeutic mechanisms of KXS for treating AD have not been fully explored. Herein, we used a comprehensive network pharmacology approach to investigate the mechanism of action of KXS in the treatment of AD. This approach consists of construction of multiple networks and Gene Ontology enrichment and pathway analyses. Furthermore, animal experiments were performed to validate the predicted molecular mechanisms obtained from the systems pharmacology-based analysis. As a result, 50 chemicals in KXS and 39 AD-associated proteins were identified as major active compounds and targets, respectively. The therapeutic mechanisms of KXS in treating AD were primarily related to the regulation of four pathology modules, including amyloid beta metabolism, tau protein hyperphosphorylation process, cholinergic dysfunction, and inflammation. In scopolamine-induced cognitive dysfunction mice, we validated the anti-inflammatory effects of KXS on AD by determining the levels of inflammation cytokines including interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α. We also found cholinergic system dysfunction amelioration of KXS is correlated with upregulation of the cholinergic receptor CHRNB2. In conclusion, our work proposes a comprehensive systems pharmacology approach to explore the underlying therapeutic mechanism of KXS for the treatment of AD.

Role of dietary fatty acids in microglial polarization in Alzheimer's disease

Microglial polarization is an utmost important phenomenon in Alzheimer’s disease that influences the brain environment. Polarization depends upon the types of responses that cells undergo, and it is characterized by receptors present on the cell surface and the secreted cytokines to the most. The expression of receptors on the surface is majorly influenced by internal and external factors such as dietary lipids. Types of fatty acids consumed through diet influence the brain environment and glial cell phenotype and types of receptors on microglia. Reports suggest that dietary habits influence microglial polarization and the switching of microglial phenotype is very important in neurodegenerative diseases. Omega-3 fatty acids have more influence on the brain, and they are found to regulate the inflammatory stage of microglia by fine-tuning the number of receptors expressed on microglia cells. In Alzheimer’s disease, one of the pathological proteins involved is Tau protein, and microtubule-associated protein upon abnormal phosphorylation detaches from the microtubule and forms insoluble aggregates. Aggregated proteins have a tendency to propagate within the neurons and also become one of the causes of neuroinflammation. We hypothesize that tuning microglia towards anti-inflammatory phenotype would reduce the propagation of Tau in Alzheimer’s disease.

Compound AD110 Acts as Therapeutic Management for Alzheimer's Disease and Stroke in Mouse and Rat Models

Anti-inflammatory therapy may be an effective therapeutic intervention for neurological diseases, such as Alzheimer's disease (AD) and stroke. As an important anti-inflammatory cytokine, interleukin-10 (IL-10) inhibits proinflammatory responses of both innate and adaptive immune cells. We tested the hypothesis that drug-induced promotion of IL-10 expression is effective in improving cognitive abilities and neurologic outcomes of AD and stroke. An orally small molecule AD110 was synthesized and subjected to in vitro and in vivo analyses. We found that AD110 enhanced IL-10 release in lipopolysaccharide (LPS)-activated BV2 microglial cells. Y-Maze and Morris water maze tests showed improved cognitive abilities in AD mice treated with AD110. Moreover, AD110 attenuated cerebral ischemic injury in a transient middle cerebral artery occlusion (tMCAO) rat model. This study not only provides a promising lead compound with IL-10-promoting activity, but also supports the hypothesis that promoting IL-10 expression is a potential therapeutic strategy for AD and stroke.

Ganoderma cochlear Metabolites as Probes to Identify a COX-2 Active Site and as in Vitro and in Vivo Anti-Inflammatory Agents

(±)-Dispirocochlearoids A-C (1-3), meroterpenoids with a 6/6/5/6/6/6 ring system, were isolated from Ganoderma cochlear. 1-3 are selective COX-2 inhibitors with an IC₅₀ value of (-)-2 at 386 nM. Site-directed mutagenesis identified His351 as a COX-2 active site. In vivo anti-inflammatory activities of (-)-2 were performed against acute lung injury in mice.

CLIC1 Protein Accumulates in Circulating Monocyte Membrane during Neurodegeneration

Pathologies that lead to neurodegeneration in the central nervous system (CNS) represent a major contemporary medical challenge. Neurodegenerative processes, like those that occur in Alzheimer’s disease (AD) are progressive, and at the moment, they are unstoppable. Not only is an adequate therapy missing but diagnosis is also extremely complicated. The most reliable method is the measurement of beta amyloid and tau peptides concentration in the cerebrospinal fluid (CSF). However, collecting liquid samples from the CNS is an invasive procedure, thus it is not suitable for a large-scale prevention program. Ideally, blood testing is the most manageable and appropriate diagnostic procedure for a massive population screening. Recently, a few candidates, including proteins or microRNAs present in plasma/serum have been identified. The aim of the present work is to propose the chloride intracellular channel 1 (CLIC1) protein as a potential marker of neurodegenerative processes. CLIC1 protein accumulates in peripheral blood mononuclear cells (PBMCs), and increases drastically when the CNS is in a chronic inflammatory state. In AD patients, both immunolocalization and mRNA quantification are able to show the behavior of CLIC1 during a persistent inflammatory state of the CNS. In particular, confocal microscopy analysis and electrophysiological measurements highlight the significant presence of transmembrane CLIC1 (tmCLIC1) in PBMCs from AD patients. Recent investigations suggest that tmCLIC1 has a very specific role. This provides an opportunity to use blood tests and conventional technologies to discriminate between healthy individuals and patients with ongoing neurodegenerative processes.