Implications of PI3K/AKT/PTEN Signaling on Superoxide Dismutases Expression and in the Pathogenesis of Alzheimer's Disease

TXNIP Regulates NLRP3 Inflammasome-Induced Pyroptosis Related to Aging via cAMP/PKA and PI3K/Akt Signaling Pathways

Aging is an inevitable natural process with time-dependent dysfunction and the occurrence of various diseases, which impose heavy burdens on individuals, families, and society. It has been reported that NLRP3 inflammasome-induced pyroptosis contributes significantly to age-related diseases and aging, while TXNIP is suggested to be involved in regulating pyroptosis mediated by NLRP3. However, the mechanism between TXNIP and NLRP3 inflammasome is still unclear. In this study, we used HT-22 cells to explore the effect of TXNIP on pyroptosis and its potential association with the aging. Also, we delved into the underlying mechanisms. Our findings revealed that TXNIP significantly augmented pyroptosis in HT-22 cells, primarily by enhancing the activation of the NLRP3 inflammasome and promoting the release of proinflammatory cytokines. Remarkably, as TXNIP levels increased, we observed a corresponding rise in the number of p16-positive cells, which is indicative of aging. Furthermore, we conducted experiments to modulate the improvement of TXNIP on NLRP3 inflammasome-induced pyroptosis, that is, the PI3K activator 740 Y-P and the PKA activator DC2797 inhibited the effect, while the PI3K inhibitor LY294002 and the PKA inhibitor H89 enhanced the effect. In conclusion, our study demonstrated that TXNIP regulates NLRP3 inflammasome-induced pyroptosis in HT-22 cells related to aging via the PI3K/Akt and cAMP/PKA pathways.

Redox Regulation of PTEN by Reactive Oxygen Species: Its Role in Physiological Processes

Phosphatase and tensin homolog (PTEN) is a tumor suppressor due to its ability to regulate cell survival, growth, and proliferation by downregulating the PI3K/AKT signaling pathway. In addition, PTEN plays an essential role in other physiological events associated with cell growth demands, such as ischemia-reperfusion, nerve injury, and immune responsiveness. Therefore, recently, PTEN inhibition has emerged as a potential therapeutic intervention in these situations. Increasing evidence demonstrates that reactive oxygen species (ROS), especially hydrogen peroxide (H2O2), are produced and required for the signaling in many important cellular processes under such physiological conditions. ROS have been shown to oxidize PTEN at the cysteine residue of its active site, consequently inhibiting its function. Herein, we provide an overview of studies that highlight the role of the oxidative inhibition of PTEN in physiological processes.

The synergistic effect of nanocurcumin and donepezil on Alzheimer's via PI3K/AKT/GSK-3β pathway modulating

Alzheimer's disease (AD) hallmarks include amyloid-βeta (Aβ) and tau proteins aggregates, neurite degeneration, microglial activation with cognitive impairment. Phosphatidylinositol-3-kinase/protein kinase B/Glycogen synthase kinase-3-beta (PI3K/AKT/GSK-3) pathway is essential for neuroprotection, cell survival and proliferation by blocking apoptosis. This study aimed to assess protective role of nanocurcumin (NCMN) as strong antioxidant and anti-inflammatory agent with elucidating its synergistic effects with Donepezil as acetylcholinesterase inhibitor on AD in rats via modulating PI3K/AKT/GSK-3β pathway. The experiment was performed on 70 male Wistar albino rats divided into seven groups (control, NCMN, Donepezil, AD-model, Donepezil co-treatment, NCMN only co-treatment, and NCMN+Donepezil combined treatment). Behavioral and biochemical investigations as cholinesterase activity, oxidative stress (malondialdehyde, reduced glutathione, nitric oxide, superoxidedismutase, and catalase), tumor necrosis factor-alpha, Tau, β-site amyloid precursor protein cleaving enzyme-1 (BACE-1), Phosphatase and tensin homolog (Pten), mitogen-activated protein kinase-1 (MAPK-1), Glycogen synthase kinase-3-beta (GSK-3β) and toll-like receptor-4 were evaluated. Treatment with NCMN improved memory, locomotion, neuronal differentiation by activating PI3K/AKT/GSK-3β pathway. These results were confirmed by histological studies in hippocampus.

Moringa oleifera leaf extract suppresses TIMM23 and NDUFS3 expression and alleviates oxidative stress induced by Aβ1-42 in neuronal cells via activation of Akt

Background and purpose

Oxidative stress plays an important role in Alzheimer's disease (AD) pathogenesis. Moringa oleifera leaf (MOL) extract has been shown to have antioxidant activities. Here, we studied the antioxidative and anti-apoptotic effects of water-soluble MOL extract in an amyloid beta (Aβ)-induced oxidative stress model of AD.

Experimental approach

The effect of amyloid beta (Aβ)1-42 and MOL extract on differentiated SH-SY5Y cell viability was assessed by MTT assay. Cells were treated with Aβ1-42, MOL extract, or MOL extract followed by Aβ1-42. The mitochondrial membrane potential (ΔΨm) and the reactive oxygen species (ROS) were evaluated by flow cytometry and dihydroethidium (DHE) assay, respectively. Western blotting was used to assess the expression of mitochondrial proteins TIMM23 and NDUFS3, apoptosis-related proteins Bax, Bcl-2, and cleaved caspase-3 along with fluorescence analysis of caspase-3/7, and Akt phosphorylation.

Findings/Results

MOL extract pretreatment at 25, 50, and 100 μg/mL prevented ΔΨm reduction. At 100-μg/mL, MOL extract decreased TIMM23 and NDUFS3 proteins and DHE signals in Aβ1-42-treated cells. MOL extract pretreatment (25, 50, and 100 μg/mL) also alleviated the apoptosis indicators, including Bax, caspase-3/7 intensity, and cleaved caspase-3, and increased Bcl-2 levels in Aβ1-42-treated cells, consistent with a reduction in the number of apoptotic cells. The protective effects of MOL extract were possibly mediated through Akt activation, evidenced by increased Akt phosphorylation.

Conclusion and implications

The neuroprotective effect of MOL extract could be mediated via the activation of Akt, leading to the suppression of oxidative stress and apoptosis in an Aβ1-42 model of AD.

Mesenchymal Stem Cells from Familial Alzheimer's Patients Express MicroRNA Differently

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the predominant form of dementia globally. No reliable diagnostic, predictive techniques, or curative interventions are available. MicroRNAs (miRNAs) are vital to controlling gene expression, making them valuable biomarkers for diagnosis and prognosis. This study examines the transcriptome of olfactory ecto-mesenchymal stem cells (MSCs) derived from individuals with the PSEN1(A431E) mutation (Jalisco mutation). The aim is to determine whether this mutation affects the transcriptome and expression profile of miRNAs and their target genes at different stages of asymptomatic, presymptomatic, and symptomatic conditions. Expression microarrays compare the MSCs from mutation carriers with those from healthy donors. The results indicate a distinct variation in the expression of miRNAs and mRNAs among different symptomatologic groups and between individuals with the mutation. Using bioinformatics tools allows us to identify target genes for miRNAs, which in turn affect various biological processes and pathways. These include the cell cycle, senescence, transcription, and pathways involved in regulating the pluripotency of stem cells. These processes are closely linked to inter- and intracellular communication, vital for cellular functioning. These findings can enhance our comprehension and monitoring of the disease's physiological processes, identify new disorder indicators, and develop innovative treatments and diagnostic tools for preventing or treating AD.

Arsenic and Tau Phosphorylation: a Mechanistic Review

Arsenic poisoning can affect the peripheral nervous system and cause peripheral neuropathy. Despite different studies on the mechanism of intoxication, the complete process is not explained yet, which can prevent further intoxication and produce effective treatment. In the following paper, we would like to consider the idea that arsenic might cause some diseases via inflammation induction, and tauopathy in neurons. Tau protein, one of the microtubule-associated proteins expressed in neurons, contributes to neuronal microtubules structure. Arsenic may be involved in cellular cascades involved in modulating tau function or hyperphosphorylation of tau protein, which ultimately leads to nerve destruction. For proof of this assumption, some investigations have been planned to measure the association between arsenic and quantities of phosphorylation of tau protein. Additionally, some researchers have investigated the association between microtubule trafficking in neurons and the levels of tau protein phosphorylation. It should be noticed that changing tau phosphorylation in arsenic toxicity may add a new feature to understanding the mechanism of poisonousness and aid in discovering novel therapeutic candidates such as tau phosphorylation inhibitors for drug development.

Zaluzanin C Alleviates Inflammation and Lipid Accumulation in Kupffer Cells and Hepatocytes by Regulating Mitochondrial ROS

Zaluzanin C (ZC), a sesquiterpene lactone isolated from Laurus nobilis L., has been reported to have anti-inflammatory and antioxidant effects. However, the mechanistic role of ZC in its protective effects in Kupffer cells and hepatocytes has not been elucidated. The purpose of this study was to elucidate the efficacy and mechanism of action of ZC in Kupffer cells and hepatocytes. ZC inhibited LPS-induced mitochondrial ROS (mtROS) production and subsequent mtROS-mediated NF-κB activity in Kupffer cells (KCs). ZC reduced mRNA levels of pro-inflammatory cytokines (Il1b and Tnfa) and chemokines (Ccl2, Ccl3, Ccl4, Cxcl2 and Cxcl9). Tumor necrosis factor (TNF)-α-induced hepatocyte mtROS production was inhibited by ZC. ZC was effective in alleviating mtROS-mediated mitochondrial dysfunction. ZC enhanced mitophagy and increased mRNA levels of fatty acid oxidation genes (Pparα, Cpt1, Acadm and Hadha) and mitochondrial biosynthetic factors (Pgc1α, Tfam, Nrf1 and Nrf2) in hepatocytes. ZC has proven its anti-lipid effect by improving lipid accumulation in hepatocytes by enhancing mitochondrial function to facilitate lipid metabolism. Therefore, our study suggests that ZC may be an effective compound for hepatoprotection by suppressing inflammation and lipid accumulation through regulating mtROS.

Exploring Circulating Long Non-Coding RNAs in Mild Cognitive Impairment Patients' Blood

Mild cognitive impairment (MCI) is a transitional clinical stage prior to dementia. Patients with amnestic MCI have a high risk of progression toward Alzheimer's disease. Both amnestic mild cognitive impairment and sporadic Alzheimer's disease are multifactorial disorders consequential from a multifaceted cross-talk among molecular and biological processes. Non-coding RNAs play an important role in the regulation of gene expression, mainly long non-coding RNAs (lncRNAs), that regulate other RNA transcripts through binding microRNAs. Cross-talk between RNAs, including coding RNAs and non-coding RNAs, produces a significant regulatory network all through the transcriptome. The relationship of genes and non-coding RNAs could improve the knowledge of the genetic factors contributing to the predisposition and pathophysiology of MCI. The objective of this study was to identify the expression patterns and relevant lncRNA-associated miRNA regulatory axes in the blood of MCI patients, which includes lncRNA-SNHG16, lncRNA-H19, and lncRNA-NEAT1. Microarray investigations have demonstrated modifications in the expression of long non-coding RNAs (lncRNA) in the blood of patients with MCI compared with control samples. This is the first study to explore lncRNA profiles in mild cognitive impairment blood. Our study proposes RNAs targets involved in molecular pathways connected to the pathogenesis of MCI.

Clinical and preclinical evaluation of miR-144-5p as a key target for major depressive disorder

BACKGROUND

Neuronal abnormalities are closely associated with major depressive disorder (MDD). Available evidence suggests a role for microRNAs (miRNAs) in regulating the expression of genes involved in MDD. Hence, miRNAs that can be potential therapeutic targets need to be identified.

METHODS

A mouse model of chronic unpredictable stress (CUS) was used to evaluate the function of miRNAs in MDD. miR-144-5p was screened from the hippocampi of CUS mice based on sequencing results. Adenovirus-associated vectors were used to overexpress or knockdown miR-144-5p in mice. BpV(pic) and LY294002 were used to determine the relationship between miR-144-5p target genes PTEN and TLR4 in neuronal impairment caused by miR-144-5p deficiency. Western blotting, immunofluorescence, ELISA immunosorbent assay, and Golgi staining were used to detect neuronal abnormalities. Serum samples from healthy individuals and patients with MDD were used to detect miR-144-5p levels in the serum and serum exosomes using qRT-PCR.

RESULTS

miR-144-5p expression was significantly decreased within the hippocampal dentate gyrus (DG) of CUS mice. Upregulation of miR-144-5p in the DG ameliorated depression-like behavior in CUS mice and attenuated neuronal abnormalities by directly targeting PTEN and TLR4 expression. Furthermore, miR-144-5p knockdown in normal mice led to depression-like behavior via inducing neuronal abnormalities, including abnormal neurogenesis, neuronal apoptosis, altered synaptic plasticity, and neuroinflammation. miR-144-5p deficiency-mediated neuronal impairment was mediated by PI3K/Akt/FoxO1 signaling. Furthermore, miR-144-5p levels were downregulated in the sera of patients with MDD and associated with depressive symptoms. Consistently, serum exosome-derived miR-144-5p levels were decreased in patients with MDD.

CONCLUSION

miR-144-5p plays a vital role in regulating neuronal abnormalities in depression. Our findings provide translational evidence that miR-144-5p is a new potential therapeutic target for MDD.

Integrated Multimodal Omics and Dietary Approaches for the Management of Neurodegeneration

Neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease, are caused by a combination of multiple events that damage neuronal function. A well-characterized biomarker of neurodegeneration is the accumulation of proteinaceous aggregates in the brain. However, the gradually worsening symptoms of neurodegenerative diseases are unlikely to be solely due to the result of a mutation in a single gene, but rather a multi-step process involving epigenetic changes. Recently, it has been suggested that a fraction of epigenetic alternations may be correlated to neurodegeneration in the brain. Unlike DNA mutations, epigenetic alterations are reversible, and therefore raise the possibilities for therapeutic intervention, including dietary modifications. Additionally, reactive oxygen species may contribute to the pathogenesis of Alzheimer's disease and Parkinson's disease through epigenetic alternation. Given that the antioxidant properties of plant-derived phytochemicals are likely to exhibit pleiotropic effects against ROS-mediated epigenetic alternation, dietary intervention may be promising for the management of neurodegeneration in these diseases. In this review, the state-of-the-art applications using single-cell multimodal omics approaches, including epigenetics, and dietary approaches for the identification of novel biomarkers and therapeutic approaches for the treatment of neurodegenerative diseases are discussed.

Overview on the Polyphenol Avenanthramide in Oats (Avena sativa Linn.) as Regulators of PI3K Signaling in the Management of Neurodegenerative Diseases

Avenanthramides (Avns) and their derivatives, a group of polyphenolic compounds found abundantly in oats (Avena sativa Linn.), have emerged as promising candidates for neuroprotection due to their immense antioxidant, anti-inflammatory, and anti-apoptotic properties. Neurodegenerative diseases (NDDs), characterized by the progressive degeneration of neurons, present a significant global health burden with limited therapeutic options. The phosphoinositide 3-kinase (PI3K) signaling pathway plays a crucial role in cell survival, growth, and metabolism, making it an attractive target for therapeutic intervention. The dysregulation of PI3K signaling has been implicated in the pathogenesis of various NDDs including Alzheimer's and Parkinson's disease. Avns have been shown to modulate PI3K/AKT signaling, leading to increased neuronal survival, reduced oxidative stress, and improved cognitive function. This review explores the potential of Avn polyphenols as modulators of the PI3K signaling pathway, focusing on their beneficial effects against NDDs. Further, we outline the need for clinical exploration to elucidate the specific mechanisms of Avn action on the PI3K/AKT pathway and its potential interactions with other signaling cascades involved in neurodegeneration. Based on the available literature, using relevant keywords from Google Scholar, PubMed, Scopus, Science Direct, and Web of Science, our review emphasizes the potential of using Avns as a therapeutic strategy for NDDs and warrants further investigation and clinical exploration.

DpdtpA, A Multi-metal Ion Chelator, Attenuates Tau Phosphorylation and Microglial Inflammatory Response via Regulating the PI3K/AKT/GSK-3β Signal Pathways

Tau protein hyperphosphorylation and formation of intracellular neurofibrillary tangles (NFTs) are one of the histopathological hallmarks of Alzheimer's disease (AD) and positively correlated with the severity of AD symptoms. NFTs contain a large number of metal ions that play an important role in regulating tau protein phosphorylation and AD progression. Extracellular tau induces primary phagocytosis of stressed neurons and neuronal loss by activating microglia. Here, we studied the effects of a multi-metal ion chelator, DpdtpA, on tau-induced microglial activation and inflammatory responses and the underlying mechanisms. Treatment with DpdtpA attenuated the increase in the expression of NF-κB and production of inflammatory cytokines, IL-1β, IL-6 and IL-10, in rat microglial cells induced by expression of human tau40 proteins. Treatment with DpdtpA also suppressed tau protein expression and phosphorylation. Moreover, treatment with DpdtpA prevented tau-induced activation of glycogen synthase kinase-3β (GSK-3β) and inhibition of phosphatidylinositol-3-hydroxy kinase (PI3K)/AKT. Collectively, these results show that DpdtpA can attenuate tau phosphorylation and inflammatory responses of microglia by regulating the PI3K/AKT/GSK-3β signal pathways, providing a new option to alleviate neuroinflammation for the treatment of AD.

Metabolic Reprogramming toward Aerobic Glycolysis and the Gut Microbiota Involved in the Brain Amyloid Pathology

Alzheimer's disease (AD) is characterized by the formation of senile plaques consisting of fibrillated amyloid-β (Aβ), dystrophic neurites, and the neurofibrillary tangles of tau. The oligomers/fibrillar Aβ damages the neurons or initiates an intracellular signaling cascade for neuronal cell death leading to Aβ toxicity. The Aβ is a 4 kDa molecular weight peptide originating from the C-terminal region of the amyloid precursor protein via proteolytic cleavage. Apart from the typical AD hallmarks, certain deficits in metabolic alterations have been identified. This study describes the emerging features of AD from the aspect of metabolic reprogramming in the main pathway of carbohydrate metabolism in the human brain. Particularly, the neurons in patients with AD favor glycolysis despite a normal mitochondrial function indicating a Warburg-like effect. In addition, certain dietary patterns are well known for their properties in preventing AD. Among those, a ketogenic diet may substantially improve the symptoms of AD. An effective therapeutic method for the treatment, mitigation, and prevention of AD has not yet been established. Therefore, the researchers pursue the development and establishment of novel therapies effective in suppressing AD symptoms and the elucidation of their underlying protective mechanisms against neurodegeneration aiming for AD therapy in the near future.

The network pharmacology study and molecular docking to investigate the potential mechanism of Acoritataninowii Rhizoma against Alzheimer's Disease

Alzheimer's Disease is considered as an insidious neurodegenerative progressive disease but its pathogenesis has not been elucidated. Acoritataninowii Rhizoma exhibits anti-dementia effects as a traditional Chinese medicine (TCM), which is linked to its anti- Alzheimer's Disease mechanism. In this study, network pharmacology and molecular docking were used to examine the potential of Acoritataninowii Rhizoma for Alzheimer's Disease. In order to construct PPI networks and drug-component-target-disease networks, disease-related genes and proteins were gathered from the database. Gene ontology (GO), pathway enrichment (KEGG), and molecular docking were used to forecast the potential mechanism of Acoritataninowii Rhizoma on Alzheimer's disease. Therefore, 4 active ingredients and 81 target genes were screened from Acoritataninowii Rhizoma, 6765 specific target genes were screened from Alzheimer's Disease, and 61 drug-disease cross genes were validated. GO analysis showed that Acoritataninowii Rhizoma can regulate processes such as the protein serine/threonine kinase associated with MAPK. KeGG pathway analysis showed that the signaling pathways affected by Acoritataninowii Rhizoma were fluid shear stress and atherosclerosis, AGE-RAGE and other pathways. Molecular docking implied that the pharmacological influences of the bioactive constituents of Acoritataninowii Rhizoma (Cycloaartenol and kaempferol) on Alzheimer's Disease may related to ESR1 and AKT1, respectively. AKT1 and ESR1 may be the core target genes of the treatment for Alzheimer's disease. Kaempferol and Cycloartenol might be core bioactive constituents for treatment.

Therapeutic Implications of Probiotics in the Gut Microbe-Modulated Neuroinflammation and Progression of Alzheimer's Disease

Alzheimer's disease (AD) is characterized by the accumulation of specific proteins in the brain. A recent study revealed that manipulating gut microbiota (GM) significantly reduced tau pathology and neurodegeneration in an apolipoprotein E isoform-dependent manner. The resilience of a healthy microbiota protects it from a variety of dysbiosis-related pathologies. Convincing evidence has demonstrated the roles of GM in the pathogenesis of AD, which are partly mediated by modified microglial activity in the brain. Therefore, modulation of GM may be a promising therapeutic option for AD prevention. In addition to providing the cells with energy and affecting microglial maturation, these microbial metabolites appear to influence neuronal function. One of the potential therapeutic approaches targeting GM may involve using probiotics. Additionally, human GM and its metabolites have also become potential therapeutic targets for developing interventions for the prevention of disorders. Synbiotics and postbiotics can also be used to treat AD by modulating GM. In addition, physical activity, exercise, and physical fitness are being considered as potential nonpharmacological therapies to reduce signaling pathways related to neuroinflammation. Therefore, interventions targeting GM might be promising strategies for health promotion.

Spotlight on Coenzyme Q10 in scopolamine-induced Alzheimer's disease: oxidative stress/PI3K/AKT/GSK 3ß/CREB/BDNF/TrKB

OBJECTIVES

Excess amyloid beta (Aβ) and oxidative stress (OS) are inextricable hallmarks of the neuronal damage associated Alzheimer's disease. Aβ-induced cognitive and memory dysfunctions are mediated through different signalling pathways as phosphatidylinositol-3-kinase (PI3K) and their downstream intermediates including protein-kinase-B, known as Akt, glycogen-synthase-kinase-3β (GSK-3β), cAMP-response-element-binding-protein (CREB), brain-derived-neurotrophic factor (BDNF) and tropomyosin-related-kinase receptor-B (TrKB). The current work aims to investigate the protective potentials of CoQ10 against scopolamine (Scop)-induced cognitive disability and the contribution of PI3K/Akt/GSK-3β/CREB/BDNF/TrKB in the neuroprotection effects.

METHODS

The chronic co-administration of CQ10 (50, 100 and 200 mg/kg/day i.p.) with Scop in Wistar rats for 6 weeks were assayed both behaviourally and biochemically.

KEY FINDINGS

CoQ10 ameliorated the Scop-induced cognitive and memory defects by restoring alterations in novel object recognition and Morris water maze behavioural tests. CoQ10 favourably changed the Scop-induced deleterious effects in hippocampal malondialdehyde, 8-hydroxy-2' deoxyguanosine, antioxidants and PI3K/Akt/GSK-3β/CREB/BDNF/TrKB levels.

CONCLUSIONS

These results exhibited the neuroprotective effects of CoQ10 on Scop-induced AD and revealed its ability to inhibit oxidative stress, amyloid deposition and to modulate PI3K/Akt/GSK-3β/CREB/BDNF/TrKB pathway.

Prolactin-induced neuroprotection against excitotoxicity is mediated via PI3K/AKT and GSK3β/NF-κB in primary cultures of hippocampal neurons

Prolactin (PRL) is a polypeptide hormone that has been reported to play a significant role in neuroprotection against neuronal excitotoxicity produced by glutamate (Glu) or kainic acid (KA) in both, in vitro and in vivo models. However, the molecular mechanisms involved in PRL's neuroprotective effects in the hippocampus have not been completely elucidated. The aim of the present study was to assess the signaling pathways involved in PRL neuroprotection against excitotoxicity. Primary rat hippocampal neuronal cell cultures were used to assess PRL-induced signaling pathway activation. The effects of PRL on neuronal viability, as well as its effects on activation of key regulatory pathways, phosphoinositide 3-kinases/Protein Kinase B (PI3K/AKT) and glycogen synthase kinase 3β / nuclear factor kappa B (GSK3β/NF-κB), were evaluated under conditions of Glutamate-induced excitotoxicity. Additionally, the effect on downstream regulated genes such as Bcl-2 and Nrf2, was assessed. Here, we show that the PI3K/AKT signaling pathway is activated by PRL treatment during excitotoxicity, promoting neuronal survival through upregulation of active AKT and GSK3β/NF-κB, resulting in induction of Bcl-2 and Nrf2 gene expression. Inhibition of the PI3K/AKT signaling pathway abrogated the protective effect of PRL against Glu-induced neuronal death. Overall, results indicate that the neuroprotective actions of PRL are mediated in part, by the activation of the AKT pathway and survival genes. Our data support the idea that PRL could be useful as a potential neuroprotective agent in different neurological and neurodegenerative diseases.

The Chemopreventive Effects of Chlorogenic Acids, Phenolic Compounds in Coffee, against Inflammation, Cancer, and Neurological Diseases

Coffee is one of the most widely consumed beverages, which has several effects on the human body. In particular, current evidence suggests that coffee consumption is associated with a reduced risk of inflammation, various types of cancers, and certain neurodegenerative diseases. Among the various constituents of coffee, phenolic phytochemicals, more specifically chlorogenic acids, are the most abundant, and there have been many attempts to utilize coffee chlorogenic acid for cancer prevention and therapy. Due to its beneficial biological effect on the human body, coffee is regarded as a functional food. In this review article, we summarize the recent advances and knowledge on the association of phytochemicals contained in coffee as nutraceuticals, with a particular focus on phenolic compounds, their intake, and nutritional biomarkers, with the reduction of disease risk, including inflammation, cancer, and neurological diseases.

The Effective Components, Core Targets, and Key Pathways of Ginseng against Alzheimer's Disease

Background

Panax ginseng C. A. Mey (ginseng) is a traditional Chinese medicinal herb used for the treatment of nervous system disorders, such as Alzheimer's disease (AD). However, the pharmacological mechanisms of ginseng involved in AD have not been systematically investigated. Here, a network pharmacology approach was adopted to explore the effective components, core targets, and key pathways of ginseng against AD.

Methods

TCMSP database was used to screen the active ingredients of ginseng. Prediction of the targets of ginseng and AD-related genes was performed using online public databases. "Compound-Target," "Compound-Target-Disease," "Protein-Protein Interaction (PPI)," "Compound-Target-Pathway," and "Compound-Target-GO-Pathway" networks were constructed with Cytoscape 3.7.2 software. Gene Ontology (GO) function annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment were performed by using the DAVID database.

Results

A total of 22 bioactive compounds were identified from ginseng, and 481 targets of ginseng and 763 AD-related targets were obtained from public databases. The PPI network screened out 19 hub genes of ginseng against AD. According to GO function enrichment, ginseng influenced cell proliferation, death, the nitric oxide biosynthetic process, hypoxia response, and synaptic transmission. Neuroactive ligand-receptor interaction, serotonergic synapse, calcium signaling, cAMP signaling, FoxO signaling, Ras signaling, and PI3K-AKT signaling were among the most key regulatory pathways. The compound-target-GO-route network found EGFR, MAPK1, MAPK14, AKT1, CASP3, and PRKACA as key genes, with PI3K-AKT signaling being the most important pathway for ginseng's anti-AD activity.

Conclusion

Ginseng exerts neuroprotective effects in AD patients through multicomponent, multitarget, and multipathway modes, providing novel insight into the pharmacological and experimental research on ginseng against AD.

Novel Dual AChE and ROCK2 Inhibitor Induces Neurogenesis via PTEN/AKT Pathway in Alzheimer's Disease Model

Alzheimer's disease (AD) is a progressive and complex neurodegenerative disease. Acetylcholinesterase inhibitors (AChEIs) are a major class of drugs used in AD therapy. ROCK2, another promising target for AD, has been associated with the induction of neurogenesis via PTEN/AKT. This study aimed to characterize the therapeutic potential of a novel donepezil-tacrine hybrid compound (TA8Amino) to inhibit AChE and ROCK2 protein, leading to the induction of neurogenesis in SH-SY5Y cells. Experiments were carried out with undifferentiated and neuron-differentiated SH-SY5Y cells submitted to treatments with AChEIs (TA8Amino, donepezil, and tacrine) for 24 h or 7 days. TA8Amino was capable of inhibiting AChE at non-cytotoxic concentrations after 24 h. Following neuronal differentiation for 7 days, TA8Amino and donepezil increased the percentage of neurodifferentiated cells and the length of neurites, as confirmed by β-III-tubulin and MAP2 protein expression. TA8Amino was found to participate in the activation of PTEN/AKT signaling. In silico analysis showed that TA8Amino can stably bind to the active site of ROCK2, and in vitro experiments in SH-SY5Y cells demonstrate that TA8Amino significantly reduced the expression of ROCK2 protein, contrasting with donepezil and tacrine. Therefore, these results provide important information on the mechanism underlying the action of TA8Amino with regard to multi-target activities.

Inhibition of Glycogen Synthase Kinase and the Neuroprotective Function of Conjugated ZnO-Osthol Nanoparticles in Alzheimer’s Disease

A critical factor in the cause and progression of Alzheimer’s disease (AD) is the growth of β-amyloid peptide (Aβ) in the brain. The mechanism of this effect is still unknown, although the effect of osthol on Aβ-induced inflammation is neuroprotective in AD and supplementation with zinc might prevent or delay the onset of dementia. In the current study, by inducing APP vector in human BE (2)-M17 cells, we established a cellular model of AD and investigated the protective effect of osthol (7-methoxy-8-3-methyl-2-butenyl-2H-1-benzopyran-2-one)-zinc oxide nanoparticles. The osthol-conjugated zinc oxide nanoparticles could significantly increase cell viability by inhibiting cell apoptosis. Osthol treatment has also prevented synaptic proteins such as postsynaptic density-95 (PSD-95), synaptophysin (SYP), and synapsin-1 from decreasing in APP-induced BE (2)-M17 cells. In addition, the expression of miR-132 was significantly upregulated by osthol by triggering the Wnt/β-catenin signaling pathway. We conclude from our observations that osthol is a potential drug for the treatment of a neurodegenerative disease, Alzheimer’s. The key reason was that by upregulating miR-132, osthol could inhibit APP expression to prevent AD from occurring.

Crocin molecular signaling pathways at a glance: A comprehensive review

Crocin is a hydrophilic carotenoid that is synthesized in the flowers of the Crocus genus. Numerous in vitro and in vivo research projects have been published about the biological and pharmacological properties and toxicity of crocin. Crocin acts as a memory enhancer, anxiolytic, aphrodisiac, antidepressant, neuroprotective, and so on. Here, we introduce an updated and comprehensive review of crocin molecular mechanisms based on previously examined and mentioned in the literature. Different studies confirmed the significant effect of crocin to control pathological conditions, including oxidative stress, inflammation, metabolic disorders, neurodegenerative disorders, and cancer. The neuroprotective effect of crocin could be related to the activation of phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT)/mammalian target of rapamycin (mTOR), Notch, and cyclic-AMP response element-binding protein signaling pathways. The crocin also protects the cardiovascular system through the inhibitory effect on toll-like receptors. The regulatory effect of crocin on PI3K/AKT/mTOR, AMP-activated protein kinase, mitogen-activated protein kinases (MAPK), and peroxisome proliferator-activated receptor pathways can play an effective role in the treatment of metabolic disorders. The crocin has anticancer activity through the PI3K/AKT/mTOR, MAPK, vascular endothelial growth factor, Wnt/β-catenin, and Janus kinases-signal transducer and activator of transcription suppression. Also, the nuclear factor-erythroid factor 2-related factor 2 and p53 signaling pathway activation may be effective in the anticancer effect of crocin. Finally, among signaling pathways regulated by crocin, the most important ones seem to be those related to the regulatory effect on the PI3K/AKT/mTOR pathway.

Long Intergenic Noncoding RNAs Affect Biological Pathways Underlying Autoimmune and Neurodegenerative Disorders

Long intergenic noncoding RNAs (lincRNAs) are a class of independently transcribed molecules longer than 200 nucleotides that do not overlap known protein-coding genes. LincRNAs have diverse roles in gene expression and participate in a spectrum of biological processes. Dysregulation of lincRNA expression can abrogate cellular homeostasis, cell differentiation, and development and can also deregulate the immune and nervous systems. A growing body of literature indicates their important and multifaceted roles in the pathogenesis of several different diseases. Furthermore, certain lincRNAs can be considered potential therapeutic targets and valuable diagnostic or prognostic biomarkers capable of predicting the onset of a disease, its degree of activity, or the progression phase. In this review, we discuss possible mechanisms and molecular functions of lincRNAs in the pathogenesis of selected autoimmune and neurodegenerative disorders: multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, Sjögren’s syndrome, Huntington’s disease, Parkinson’s disease, Alzheimer’s disease, and amyotrophic lateral sclerosis. This summary can provide new ideas for future research, diagnosis, and treatment of these highly prevalent and devastating diseases.

The role and therapeutic implication of protein tyrosine phosphatases in Alzheimer's disease

Protein tyrosine phosphatases (PTPs) are important regulator of neuronal signal transduction and a growing number of PTPs have been implicated in Alzheimer's disease (AD). In the brains of patients with AD, there are a variety of abnormally phosphorylated proteins, which are closely related to the abnormal expression and activity of PTPs. β-Amyloid plaques (Aβ) and hyperphosphorylated tau protein are two pathological hallmarks of AD, and their accumulation ultimately leads to neurodegeneration. Studies have shown that protein phosphorylation signaling pathways mediates intracellular accumulation of Aβ and tau during AD development and are involved in synaptic plasticity and other stress responses. Here, we summarized the roles of PTPs related to the pathogenesis of AD and analyzed their therapeutic potential in AD.

Identification of Alzheimer’s Disease Molecular Subtypes Based on Parallel Large-Scale Sequencing

The incidence of Alzheimer’s disease (AD) is constantly increasing as the older population grows, and no effective treatment is currently available. In this study, we focused on the identification of AD molecular subtypes to facilitate the development of effective drugs. AD sequencing data collected from the Gene Expression Omnibus (GEO) database were subjected to cluster sample analysis. Each sample module was then identified as a specific AD molecular subtype, and the biological processes and pathways were verified. The main long non-coding RNAs and transcription factors regulating each “typing pathway” and their potential mechanisms were determined using the RNAInter and TRRUST databases. Based on the marker genes of each “typing module,” a classifier was developed for molecular typing of AD. According to the pathways involved, five sample clustering modules were identified (mitogen-activated protein kinase, synaptic, autophagy, forkhead box class O, and cell senescence), which may be regulated through multiple pathways. The classifier showed good classification performance, which may be useful for developing novel AD drugs and predicting their indications.

Shared Molecular Mechanisms among Alzheimer’s Disease, Neurovascular Unit Dysfunction and Vascular Risk Factors: A Narrative Review

Alzheimer’s disease (AD) is the most common type of dementia, affecting 24 million individuals. Clinical and epidemiological studies have found several links between vascular risk factors (VRF), neurovascular unit dysfunction (NVUd), blood-brain barrier breakdown (BBBb) and AD onset and progression in adulthood, suggesting a pathogenetic continuum between AD and vascular dementia. Shared pathways between AD, VRF, and NVUd/BBB have also been found at the molecular level, underlining the strength of this association. The present paper reviewed the literature describing commonly shared molecular pathways between adult-onset AD, VRF, and NVUd/BBBb. Current evidence suggests that VRF and NVUd/BBBb are involved in AD neurovascular and neurodegenerative pathology and share several molecular pathways. This is strongly supportive of the hypothesis that the presence of VRF can at least facilitate AD onset and progression through several mechanisms, including NVUd/BBBb. Moreover, vascular disease and several comorbidities may have a cumulative effect on VRF and worsen the clinical manifestations of AD. Early detection and correction of VRF and vascular disease by improving NVUd/BBBd could be a potential target to reduce the overall incidence and delay cognitive impairment in AD.

Symptomatic, Genetic, and Mechanistic Overlaps between Autism and Alzheimer's Disease

Autism spectrum disorder (ASD) and Alzheimer's disease (AD) are neurodevelopmental and neurodegenerative disorders affecting two opposite ends of life span, i.e., childhood and old age. Both disorders pose a cumulative threat to human health, with the rate of incidences increasing considerably worldwide. In the context of recent developments, we aimed to review correlated symptoms and genetics, and overlapping aspects in the mechanisms of the pathogenesis of ASD and AD. Dementia, insomnia, and weak neuromuscular interaction, as well as communicative and cognitive impairments, are shared symptoms. A number of genes and proteins linked with both disorders have been tabulated, including MECP2, ADNP, SCN2A, NLGN, SHANK, PTEN, RELN, and FMR1. Theories about the role of neuron development, processing, connectivity, and levels of neurotransmitters in both disorders have been discussed. Based on the recent literature, the roles of FMRP (Fragile X mental retardation protein), hnRNPC (heterogeneous ribonucleoprotein-C), IRP (Iron regulatory proteins), miRNAs (MicroRNAs), and α-, β0, and γ-secretases in the posttranscriptional regulation of cellular synthesis and processing of APP (amyloid-β precursor protein) have been elaborated to describe the parallel and overlapping routes and mechanisms of ASD and AD pathogenesis. However, the interactive role of genetic and environmental factors, oxidative and metal ion stress, mutations in the associated genes, and alterations in the related cellular pathways in the development of ASD and AD needs further investigation.

The Perspective of Dysregulated LncRNAs in Alzheimer's Disease: A Systematic Scoping Review

LncRNAs act as part of non-coding RNAs at high levels of complex and stimulatory configurations in basic molecular mechanisms. Their extensive regulatory activity in the CNS continues on a small scale, from the functions of synapses to large-scale neurodevelopment and cognitive functions, aging, and can be seen in both health and disease situations. One of the vast consequences of the pathological role of dysregulated lncRNAs in the CNS due to their role in a network of regulatory pathways can be manifested in Alzheimer's as a neurodegenerative disease. The disease is characterized by two main hallmarks: amyloid plaques due to the accumulation of β-amyloid components and neurofibrillary tangles (NFT) resulting from the accumulation of phosphorylated tau. Numerous studies in humans, animal models, and various cell lines have revealed the role of lncRNAs in the pathogenesis of Alzheimer's disease. This scoping review was performed with a six-step strategy and based on the Prisma guideline by systematically searching the publications of seven databases. Out of 1,591 records, 69 articles were utterly aligned with the specified inclusion criteria and were summarized in the relevant table. Most of the studies were devoted to BACE1-AS, NEAT1, MALAT1, and SNHG1 lncRNAs, respectively, and about one-third of the studies investigated a unique lncRNA. About 56% of the studies reported up-regulation, and 7% reported down-regulation of lncRNAs expressions. Overall, this study was conducted to investigate the association between lncRNAs and Alzheimer's disease to make a reputable source for further studies and find more molecular therapeutic goals for this disease.

Long noncoding RNA ZFAS1 aggravates spinal cord injury by binding with miR-1953 and regulating the PTEN/PI3K/AKT pathway

Multiple evidence has shown that long non-coding RNAs (lncRNAs) are novel modulators in the development of many neurological diseases, including spinal cord injury (SCI). Recently, a novel lncRNA zinc finger antisense 1 (ZFAS1) has been found to facilitate the development of many human diseases. However, the effect of ZFAS1 in SCI has not been explored. In the present study, we used the SCI mouse models and LPS-treated BV-2 cellular models to explore the role of ZFAS1 in SCI. Basso Mouse Scale score was applied to reveal locomotor function. Cresyl violet staining was used to reveal volume of spared myelin around the lesion in the injured cord. RIP and luciferase reporter assay were applied to detect binding capacity among RNAs. Next, ZFAS1 was identified to be upregulated in spinal cord tissues of SCI mice. ZFAS1 knockdown promoted functional recovery and inhibited cell apoptosis and the inflammatory response in SCI mice. ZFAS1 bound with microRNA 1953 (miR-1953), and miR-1953 was downregulated in spinal cord tissues of SCI mice. Furthermore, we confirmed that ZFAS1 promoted SCI progression via binding with miR-1953. In addition, phosphatase and tensin homolog (PTEN) was verified to be a downstream target for miR-1953 in vitro, and PTEN was upregulated in spinal cord tissues of SCI mice. Finally, we illustrated that ZFAS1 inactivated the PI3K/AKT pathway through upregulation of PTEN. In conclusion, our study revealed that ZFAS1 facilitated SCI by binding with miR-1953 and regulating the PTEN/PI3K/AKT pathway, which may provide a potential novel insight for treatment of SCI.

SRY-Box 21 Antisense RNA 1 Knockdown Diminishes Amyloid Beta25-35-Induced Neuronal Damage by miR-132/PI3K/AKT Pathway

Our study aimed to explore the function and mechanism of action of long noncoding RNA (lncRNA) SRY-Box 21 antisense RNA 1 (SOX21-AS1) in amyloid beta_25-35 (Aβ_25-35)-induced neuronal damage. To induce neuronal damage, neuronal cells and differentiated IMR-32 neuroblastoma cells were challenged by Aβ_25-35. SOX21-AS1 and miR-132 quantities were detected by quantitative reverse transcription polymerase chain reaction. Cell damage was evaluated by detecting the changes of cell viability, apoptosis, and oxidative stress. Cell viability was measured using cell counting kit-8. Cell apoptosis was evaluated by flow cytometry and caspase-3 activity. The oxidative stress was analyzed by reactive oxygen species level. The expression of proteins associated with the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway was examined by western blot. SOX21-AS1 abundance was up-regulated in Aβ_25-35-challenged neuronal cells. Silencing of SOX21-AS1 attenuated Aβ_25-35-induced viability reduction and promotion of apoptosis and oxidative stress, suggesting that silencing of SOX21-AS1 repressed Aβ_25-35-induced neuronal damage. miR-132 quantity was reduced in Aβ_25-35-challenged neuronal cells, and negatively controlled by SOX21-AS1. miR-132 knockdown abolished the effect of SOX21-AS1 silencing on Aβ_25-35-induced neuronal damage, indicating that SOX21-AS1 controls Aβ_25-35-induced neuronal damage via regulating miR-132. The PI3K/AKT signaling was repressed in Aβ_25-35-challenged cells, but this effect was counteracted upon overexpression of miR-132. In conclusion, SOX21-AS1 knockdown mitigated Aβ_25-35-dependent neuronal cell damage by promoting miR-132/PI3K/AKT pathway.

Mechanistic insights into the anti-depressant effect of emodin: an integrated systems pharmacology study and experimental validation

Depression is a complex neuropsychiatric disease involved multiple targets and signaling pathways. Systems pharmacology studies could potentially present a comprehensive molecular mechanism to delineate the anti-depressant effect of emodin (EMO). In this study, we investigated the anti-depressant effects of EMO in the chronic unpredictable mild stress (CUMS) rat model of depression and gained insights into the underlying mechanisms using systems pharmacology and molecular simulation analysis. Forty-three potential targets of EMO for treatment of depression were obtained. GO biological process analysis suggested that the biological functions of these targets mainly involve the regulation of reactive oxygen species metabolic process, response to lipopolysaccharide, regulation of inflammatory response, etc. KEGG pathway enrichment analysis showed that the PI3K-Akt signaling pathway, insulin resistance, IL-17 signaling pathway were the most significantly enriched signaling pathways. The molecular docking analysis revealed that EMO might have a strong combination with ESR1, AKT1 and GSK3B. Immunohistochemical staining and Western blotting showed that 2 weeks' EMO treatment (80 mg/kg/day) reduced depression related microglial activation, neuroinflammation and altered PI3K-Akt signaling pathway. Our findings provide a systemic pharmacology basis for the anti-depressant effects of EMO.

lncRNA-Associated Competitive Endogenous RNA Regulatory Network in an Aβ25-35-Induced AD Mouse Model Treated with Tripterygium Glycoside

BACKGROUND

Tripterygium glycoside (TG) has been suggested to have protective effects on the diseases of the central nervous system including Alzheimer's disease (AD). The mechanisms involving lncRNA-associated competing endogenous RNAs (ceRNAs) were shown to play important roles in the development of AD. However, the ceRNA mechanism of TG in treating AD is still unknown. Thus, we aimed to explore the ceRNA mechanism in the treatment of AD with TG.

METHODS

A total of 32 C57BL/6J mice were administered 3 µL of Aβ25-35 (dual side, 1 mg/mL) by a single stereotactic injection in the brain to conduct AD mouse model. AD mouse models were randomly selected and divided into the AD+normal saline (NS) group (n=16) and the AD+TG group (n=16). The expression data of lncRNAs, mRNAs, and miRNAs in the hippocampus of mice from AD+NS group (n=3) and the AD+TG group (n=3) were obtained by microarray analysis. The MuTaME method was used to predict the ceRNA regulatory network. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed using the DAVID database. A protein-protein interaction (PPI) network was constructed by using STRING software.

RESULTS

TG can significantly improve spatial memory and inhibit the production of p-tau in an Aβ25-35-induced AD mouse model. A total of 661 differentially expressed lncRNAs, 503 mRNAs, and 13 miRNAs were identified. A ceRNA network involving the top 200 mRNA-miRNA-lncRNA pairs with 16 lncRNAs, 11 miRNAs, and 52 mRNAs was visualized. And a PPI network complex filtered 26 gene nodes in DEGs was predicted.

CONCLUSION

We have identified 503 DEGs, 661 DElncRNAs, and 13 DEmiRNAs during treatment with TG in Aβ25-35-induced AD mouse model. A ceRNA network based on the DElncRNAs, DEmRNAs, and DEmiRNAs was conducted, which provided new insight into the lncRNA-mediated ceRNA regulatory mechanisms underlying the effects of TG in the treatment of AD.

PI3K/AKT Signal Pathway: A Target of Natural Products in the Prevention and Treatment of Alzheimer's Disease and Parkinson's Disease

Alzheimer’s disease (AD) and Parkinson’s disease (PD) are two typical neurodegenerative diseases that increased with aging. With the emergence of aging population, the health problem and economic burden caused by the two diseases also increase. Phosphatidylinositol 3-kinases/protein kinase B (PI3K/AKT) signaling pathway regulates signal transduction and biological processes such as cell proliferation, apoptosis and metabolism. According to reports, it regulates neurotoxicity and mediates the survival of neurons through different substrates such as forkhead box protein Os (FoxOs), glycogen synthase kinase-3β (GSK-3β), and caspase-9. Accumulating evidences indicate that some natural products can play a neuroprotective role by activating PI3K/AKT pathway, providing an effective resource for the discovery of potential therapeutic drugs. This article reviews the relationship between AKT signaling pathway and AD and PD, and discusses the potential natural products based on the PI3K/AKT signaling pathway to treat two diseases in recent years, hoping to provide guidance and reference for this field. Further development of Chinese herbal medicine is needed to treat these two diseases.

Decoding signaling pathways involved in prolactin-induced neuroprotection: A review

It has been well recognized that prolactin (PRL), a pleiotropic hormone, has many functions in the brain, such as maternal behavior, neurogenesis, and neuronal plasticity, among others. Recently, it has been reported to have a significant role in neuroprotection against excitotoxicity. Glutamate excitotoxicity is a common alteration in many neurological and neurodegenerative diseases, leading to neuronal death. In this sense, several efforts have been made to decrease the progression of these pathologies. Despite various reports of PRL's neuroprotective effect against excitotoxicity, the signaling pathways that underlie this mechanism remain unclear. This review aims to describe the most recent and relevant studies on the molecular signaling pathways, particularly, PI3K/AKT, NF-κB, and JAK2/STAT5, which are currently under investigation and might be implicated in the molecular mechanisms that explain the PRL effects against excitotoxicity and neuroprotection. Remarkable neuroprotective effects of PRL might be useful in the treatment of some neurological diseases.

In silico Analysis of Polymorphisms in microRNAs Deregulated in Alzheimer Disease

BACKGROUND

Alzheimer's disease (AD) is a degenerative condition characterized by progressive cognitive impairment and dementia. Findings have revolutionized current knowledge of miRNA in the neurological conditions. Two regulatory mechanisms determine the level of mature miRNA expression; one is miRNA precursor processing, and the other is gene expression regulation by transcription factors. This study is allocated to the in-silico investigation of miRNA's SNPs and their effect on other cell mechanisms.

METHODS

We used databases which annotate the functional effect of SNPs on mRNA-miRNA and miRNA-RBP interaction. Also, we investigated SNPs which are located on the promoter or UTR region.

RESULTS

miRNA SNP3.0 database indicated several SNPs in miR-339 and miR-34a in the upstream and downstream of pre-miRNA and mature miRNAs. While, for some miRNAs miR-124, and miR-125, no polymorphism was observed, and also miR-101 with ΔG -3.1 and mir-328 with ΔG 5.8 had the highest and lowest potencies to produce mature microRNA. SNP2TFBS web-server presented several SNPs which altered the Transcription Factor Binding Sites (TFBS) or generated novel TFBS in the promoter regions of related miRNA. At last, RBP-Var database provided a list of SNPs which alter miRNA-RBP interaction pattern and can also influence other miRNAs' expression.

DISCUSSION

The results indicated that SNPs microRNA affects both miRNA function and miRNA expression. Our study expands molecular insight into how SNPs in different parts of miRNA, including the regulatory (promoter), the precursor (pre-miRNA), functional regions (seed region of mature miRNA), and RBP-binding motifs, which theoretically may be correlated to the Alzheimer's disease.

A new insulin-sensitive enhancer from Silene viscidula, WPTS, treats type 2 diabetes by ameliorating insulin resistance, reducing dyslipidemia, and promoting proliferation of islet β cells

Wacao pentacyclic triterpenoid saponins (WPTS) is a newly discovered insulin sensitivity enhancer. It is a powerful hypoglycemic compound derived from Silene viscidula, which has a hypoglycemic effect similar to that of insulin. It can rapidly reduce blood glucose levels, normalizing them within 3 days of administration. However, its mechanism of action is completely different from that of insulin. Thus, we aimed to determine the pharmacological effects and mechanism of activity of WPTS on type 2 diabetes to elucidate the main reasons for its rapid effects. The results showed that WPTS could effectively improve insulin resistance in KKAy diabetic mice. Comparative transcriptomics showed that WPTS could upregulate the expression of insulin resistance-related genes such as glucose transporter type 4 (Glut4), insulin receptor substrate 1 (Irs1), Akt, and phosphoinositide 3-kinase (PI3K), and downregulate the expression of lipid metabolism-related genes such as monoacylglycerol O-acyltransferase 1 (Moat1), lipase C (Lipc), and sphingomyelin phosphodiesterase 4 (Smpd4). The results indicated that the differentially expressed genes could regulate lipid metabolism via the PI3K/AKT metabolic pathway, and it is noteworthy that WPTS was found to upregulate Glut4 expression, decrease blood glucose levels, and attenuate insulin resistance via the PI3K/AKT pathway. Q-PCR and western blotting further validated the transcriptomics findings at the mRNA and protein levels, respectively. We believe that WPTS can achieve a rapid hypoglycemic effect by improving the lipid metabolism and insulin resistance of the diabetic KKAy mice. WPTS could be a very promising candidate drug for the treatment of diabetes and deserves further research.

An evaluation of the molecular mode of action of trans-resveratrol in the Porphyromonas gingivalis lipopolysaccharide challenged neuronal cell model

Porphyromonas gingivalis triggers a range of innate immune responses in the host that may contribute to the development of periodontitis and dementing diseases including Alzheimer's disease (AD). This study aimed to assess the mode of action of trans-resveratrol in modulating the P. gingivalis lipopolysaccharide (PgLPS) induced metabolic inflammation in a neuronal cell model. Confluent IMR-32 neuroblastoma cells were treated with trans-resveratrol from Polygonum cuspidatum in the presence or absence of PgLPS. The abundance of messenger ribo-nucleic acid (mRNA) transcripts of a panel of 92 genes was quantitatively assessed through targeted transcriptome profiling technique and the biochemical pathways affected were identified through Ingenuity Pathway Analysis. Gene expression analysis revealed that trans-resveratrol down-regulated the mRNA of multiple gene markers including growth factors, transcription factors, kinases, trans-membrane receptors, cytokines and enzymes that were otherwise activated by PgLPS treatment of IMR-32 neuroblastoma cells. Pathway analysis demonstrated that the cellular oxidative stress caused by the activation of phosphoinositide-3-kinase/Akt1 (PI3K/Akt1) pathway that leads to the production of reactive oxygen species (ROS), chronic inflammatory response induced by the activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) pathway and nutrient utilization pathways were favourably modulated by trans-resveratrol in the PgLPS challenged IMR-32 cells. This study demonstrates the potential of trans-resveratrol as a bioactive compound with multiple modes of intracellular action further supporting its therapeutic application in neuroinflammatory diseases.

Liver Growth Factor "LGF" as a Therapeutic Agent for Alzheimer's Disease

Alzheimer's disease (AD) is a progressive degenerative disorder and the most common cause of dementia in aging populations. Although the pathological hallmarks of AD are well defined, currently no effective therapy exists. Liver growth factor (LGF) is a hepatic albumin-bilirubin complex with activity as a tissue regenerating factor in several neurodegenerative disorders such as Parkinson's disease and Friedreich's ataxia. Our aim here was to analyze the potential therapeutic effect of LGF on the APPswe mouse model of AD. Twenty-month-old mice received intraperitoneal (i.p.) injections of 1.6 µg LGF or saline, twice a week during three weeks. Mice were sacrificed one week later, and the hippocampus and dorsal cortex were prepared for immunohistochemical and biochemical studies. LGF treatment reduced amyloid-β (Aβ) content, phospho-Tau/Tau ratio and the number of Aβ plaques with diameter larger than 25 µm. LGF administration also modulated protein ubiquitination and HSP70 protein levels, reduced glial reactivity and inflammation, and the expression of the pro-apoptotic protein Bax. Because the administration of this factor also restored cognitive damage in APPswe mice, we propose LGF as a novel therapeutic tool that may be useful for the treatment of AD.

Antioxidant, antimicrobial and neuroprotective effects of Octaviania asterosperma in vitro

Octaviania asterosperma (hypogeous Basidiomycota) We investigated the phenolic composition, and antioxidant, antimicrobial and antigenotoxic effects of methanol extracts of fruiting bodies from Octaviania asterosperma. The total phenolic content (ppm) of O. asterosperma was found to be catechin (54.73 ± 4.68), epicatechin (123.90 ± 8.52), caffeic acid (4.23 ± 0.97), p-hydroxybenzoic acid (37.72 ± 3.84), cinnamic acid (58.07 ± 5.40), gallic acid (56.64 ± 6.39), clorogenic acid (80.76 ± 4.92) and coumaric acid (2.45 ± 0.15). The total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI) were 3.410 ± 0.099 mmol/L, 7.548 ± 0.147 μmol/L and 0.221 ± 0.005 respectively. O. asterosperma showed some promising antimicrobial activity. The extract showed no genotoxic potential and attenuated hydrogen peroxide (H2O2)-induced oxidative DNA damage in neurons. Pre-treatment with O. asterosperma maintained mitochondrial function, reduced expression levels of cleaved-caspase-3 and apoptosis-inducing factor (AIF) when HT22 cells were exposed to pathophysiological concentrations of GLU (25 mM) and modulated protein kinase B (Akt), the mammalian target of rapamycin (mTOR), and the phosphotase and tensin homolog on chromosome ten (PTEN). O. asterosperma is an important food for the treatment or management of neurodegenerative disorders due to its phenolic content and potent antioxidant and anti-excitotoxic effects.

Oxidative Stress in Alzheimer's Disease: In Vitro Therapeutic Effect of Amniotic Fluid Stem Cells Extracellular Vesicles

Alzheimer's disease (AD) is characterized by abnormal protein aggregation, deposition of extracellular β-amyloid proteins (Aβ), besides an increase of oxidative stress. Amniotic fluid stem cells (AFSCs) should have a therapeutic potential for neurodegenerative disorders, mainly through a paracrine effect mediated by extracellular vesicles (EV). Here, we examined the effect of EV derived from human AFSCs (AFSC-EV) on the disease phenotypes in an AD neuron primary culture. We observed a positive effect of AFSC-EV on neuron morphology, viability, and Aβ and phospho-Tau levels. This could be due to the apoptotic and autophagic pathway modulation derived from the decrease in oxidative stress. Indeed, reactive oxygen species (ROS) were reduced, while GSH levels were enhanced. This modulation could be ascribed to the presence of ROS regulating enzymes, such as SOD1 present into the AFSC-EV themselves. This study describes the ROS-modulating effects of extracellular vesicles alone, apart from their deriving stem cell, in an AD in vitro model, proposing AFSC-EV as a therapeutic tool to stop the progression of AD.

1,25(OH)2D3 Alleviates Aβ(25-35)-Induced Tau Hyperphosphorylation, Excessive Reactive Oxygen Species, and Apoptosis Through Interplay with Glial Cell Line-Derived Neurotrophic Factor Signaling in SH-SY5Y Cells

Amyloid beta (Aβ) accumulation in the brain is one of the major pathological features of Alzheimer's disease. The active form of vitamin D (1,25(OH)₂D₃), which acts via its nuclear hormone receptor, vitamin D receptor (VDR), has been implicated in the treatment of Aβ pathology, and is thus considered as a neuroprotective agent. However, its underlying molecular mechanisms of action are not yet fully understood. Here, we aim to investigate whether the molecular mechanisms of 1,25(OH)₂D₃ in ameliorating Aβ toxicity involve an interplay of glial cell line-derived neurotrophic factor (GDNF)-signaling in SH-SY5Y cells. Cells were treated with Aβ(25-35) as the source of toxicity, followed by the addition of 1,25(OH)₂D₃ with or without the GDNF inhibitor, heparinase III. The results show that 1,25(OH)₂D₃ modulated Aβ-induced reactive oxygen species, apoptosis, and tau protein hyperphosphorylation in SH-SY5Y cells. Additionally, 1,25(OH)₂D₃ restored the decreasing GDNF and the inhibited phosphorylation of the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt)/glycogen synthase kinase-3β (GSK-3β) protein expressions. In the presence of heparinase III, these damaging effects evoked by Aβ were not abolished by 1,25(OH)₂D_3. It appears 1,25(OH)₂D₃ is beneficial for the alleviation of Aβ neurotoxicity, and it might elicit its neuroprotection against Aβ neurotoxicity through an interplay with GDNF-signaling.

Characterization of the chromatin accessibility in an Alzheimer's disease (AD) mouse model

Background

The pathological hallmarks of Alzheimer’s disease (AD) involve alterations in the expression of numerous genes associated with transcriptional levels, which are determined by chromatin accessibility. Here, the landscape of chromatin accessibility was studied to understand the outline of the transcription and expression of AD-associated metabolism genes in an AD mouse model.

Methods

The assay for transposase-accessible chromatin by sequencing (ATAC-seq) was used to investigate the AD-associated chromatin reshaping in the APPswe/PS1dE9 (APP/PS1) mouse model. ATAC-seq data in the hippocampus of 8-month-old APP/PS1 mice were generated, and the relationship between chromatin accessibility and gene expression was analyzed in combination with RNA sequencing. Gene ontology (GO) analysis was applied to elucidate biological processes and signaling pathways altered in APP/PS1 mice. Critical transcription factors were identified; alterations in chromatin accessibility were further confirmed using chromatin immunoprecipitation assays.

Results

We identified 1690 increased AD-associated chromatin-accessible regions in the hippocampal tissues of APP/PS1 mice. These regions were enriched in genes related to diverse signaling pathways, including the PI3K-Akt, Hippo, TGF-β, and Jak-Stat signaling pathways, which play essential roles in regulating cell proliferation, apoptosis, and inflammatory responses. A total of 1003 decreased chromatin-accessible regions were considered to be related with declined AD-associated biological processes including cellular response to hyperoxia and insulin stimulus, synaptic transmission, and positive regulation of autophagy. In the APP/PS1 hippocampus, 1090 genes were found to be upregulated and 1081 downregulated. Interestingly, enhanced ATAC-seq signal was found in approximately 740 genes, with 43 exhibiting upregulated mRNA levels. Several genes involved in AD development were found to have a significantly increased expression in APP/PS1 mice compared to controls, including Sele, Clec7a, Cst7, and Ccr6. The signatures of numerous transcription factors, including Olig2, NeuroD1, TCF4, and NeuroG2, were found enriched in the AD-associated accessible chromatin regions. The transcription-activating marks of H3K4me3 and H3K27ac were also found increased in the promoters of these genes. These results indicate that the mechanism for the upregulation of genes could be attributed to the enrichment of open chromatin regions with transcription factors motifs and the histone marks H3K4me3 and H3K27ac.

Conclusion

Our study reveals that alterations in chromatin accessibility may be an initial mechanism in AD pathogenesis.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s13195-020-00598-2.

Dietary habits, lifestyle factors and neurodegenerative diseases

Worldwide stroke is increasing in parallel with modernization, changes in lifestyle, and the growing elderly population. Our review is focused on the link between diet, as part of 'modern lifestyle', and health in the context of genetic predisposition of individuals to 'unhealthy' metabolic pathway activity. It is concluded that lifestyle including high sugar diets, alcohol and tobacco addiction or high fat diets as well as ageing, brain injury, oxidative stress and neuroinflammation, negatively influence the onset, severity and duration of neurodegenerative diseases. Fortunately, there are several healthy dietary components such as polyunsaturated fatty acids and the anti-oxidants curcumin, resveratrol, blueberry polyphenols, sulphoraphane, salvionic acid as well as caloric restriction and physical activity, which may counteract ageing and associated neurodegenerative diseases via increased autophagy or increased neurogenesis in the adult brain.

Curcumin exerts protective effects against hypoxia‑reoxygenation injury via the enhancement of apurinic/apyrimidinic endonuclease 1 in SH‑SY5Y cells: Involvement of the PI3K/AKT pathway

Curcumin, a polyphenolic compound extracted from the plant Curcuma longa, has been reported to exert neuroprotective effects against cerebral ischemia reperfusion (I/R) injury. However, the mechanisms underlying these effects remain to be fully elucidated. Emerging evidence indicated that apurinic/apyrimidinic endonuclease 1 (APE1), a multifunctional enzyme, participates in neuronal survival against I/R injury. Therefore, the aim of the present study was to investigate whether curcumin alleviates oxygen-glucose deprivation/reper-fusion (OGD/R)-induced SH-SY5Y cell injury, which serves as an in vitro model of cerebral I/R injury, by regulating APE1. The results revealed that curcumin increased cell viability, decreased LDH activity, reduced apoptosis and caspase-3 activity, downregulated the pro-apoptotic protein Bax expression and upregulated the anti-apoptotic protein Bcl-2 expression in SH-SY5Y cells subjected to OGD/R. Simultaneously, curcumin eliminated the OGD/R-induced decreases in APE1 protein and mRNA expression, as well as 8-hydroxy-2′-deoxyguanosine (8-OHdG) level and AP sites in SH-SY5Y cells. However, APE1 knockdown by siRNA transfection markedly abrogated the protective effects of curcumin against OGD/R-induced cytotoxicity, apoptosis and oxidative stress, as illustrated by the decreases in reactive oxygen species production and NADPH oxidase 2 expression, and the increase in superoxide dismutase activity and glutathione levels in SH-SY5Y cells. Furthermore, curcumin mitigated the OGD/R-induced activation of phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway. Treatment with LY294002, an inhibitor of PI3K/AKT pathway activity, attenuated the protective effects of curcumin on cytotoxicity and apoptosis, and reversed the curcumin-induced upregulation of APE1 protein expression in SH-SY5Y cells subjected to OGD/R. Taken together, these results demonstrated that curcumin protects SH-SY5Y cells against OGD/R injury by inhibiting apoptosis and oxidative stress, and via enhancing the APE1 level and activity, promoting PI3K/AKT pathway activation.

Ovarian Hormone-Dependent Effects of Dietary Lipids on APP/PS1 Mouse Brain

The formation of senile plaques through amyloid-β peptide (Aβ) aggregation is a hallmark of Alzheimer’s disease (AD). Irrespective of its actual role in the synaptic alterations and cognitive impairment associated with AD, different therapeutic approaches have been proposed to reduce plaque formation. In rodents, daily intake of omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFAs) is required for neural development, and there is experimental and epidemiological evidence that their inclusion in the diet has positive effects on several neurodegenerative diseases. Similarly, estradiol appears to reduce senile plaque formation in primary mouse cell cultures, human cortical neurons and mouse AD models, and it prevents Aβ toxicity in neural cell lines. We previously showed that differences in dietary n-6/n-3 LC-PUFAs ratios modify the lipid composition in the cerebral cortex of female mice and the levels of amyloid precursor protein (APP) in the brain. These effects depended in part on the presence of circulating estradiol. Here we explored whether this potentially synergistic action between diet and ovarian hormones may influence the progression of amyloidosis in an AD mouse model. Our results show that a diet with high n-3 LC-PUFA content, especially DHA (22:6n-3), reduces the hippocampal accumulation of Aβ_1–40, but not amyloid Aβ_1–42 in female APPswe/PS1 E9A mice, an effect that was counteracted by the loss of the ovaries and that depended on circulating estradiol. In addition, this interaction between dietary lipids and ovarian function also affects the composition of the brain lipidome as well as the expression of certain neuronal signaling and synaptic proteins. These findings provide new insights into how ovarian hormones and dietary composition affect the brain lipidome and amyloid burden. Furthermore, they strongly suggest that when designing dietary or pharmacological strategies to combat human neurodegenerative diseases, hormonal and metabolic status should be specifically taken into consideration as it may affect the therapeutic response.

Enhanced Neuroprotective Effects of Panax ginseng G115® and Ginkgo biloba GK501® Combinations In Vitro Models of Excitotoxicity

Neurological-related disorders are seen as an increasingly important aspect of welfare. While conventional medicine is still the mainstay for the treatment of these diseases, it is becoming apparent that patients are also seeking more natural and preventative interventions. Panax ginseng G115^® and Ginkgo biloba GK501^® extracts alone or in combination were used in two in vitro experimental models of primary cultures exposed to excitotoxicity: rat organotypic hippocampal slices exposed to either 5 µM kainic acid or 10 µM N-Methyl-d-aspartate for 24 hours, and mixed cortical cells exposed to 300 µM NMDA for 10 min. Cell death in the Cornu Ammonis areas CA3 or CA1 subregions of slices was quantified by measuring propidium iodide fluorescence, whereas in cortical cells, it was assessed by measuring the amount of lactate dehydrogenase. In slices, treatment with extracts alone or in combination significantly attenuated CA3 and CA1 damage induced by exposure to kainic acid or NMDA, respectively. A similar neuroprotective effect was observed in cortical cells exposed to NMDA. Analysis of cell signaling pathways found that the two extracts induced an increase of the phosphorylation and they reversed the decrease of phosphorylation of ERK1/2 and Akt induced by kainic acid and NMDA in organotypic hippocampal slices. These results suggest that P. ginseng G115^® and G. biloba GK501^® extracts may mediate their effects by activating phosphorylation of ERK1/2 and Akt signaling pathways, protecting against excitotoxicity-induced damage in in vitro models.