Linking Alzheimer's disease to insulin resistance: the FoxO response to oxidative stress

Brain insulin resistance in Down syndrome: Involvement of PI3K-Akt/mTOR axis in early-onset of Alzheimer's disease and its potential as a therapeutic target

Down syndrome (DS) is the most common genetic cause of intellectual impairment, characterised by an extra copy of chromosome 21. After the age of 40, DS individuals are highly susceptible to accelerated ageing and the development of early-onset Alzheimer-like neuropathology. In the context of DS, the brain presents a spectrum of neuropathological mechanisms and metabolic anomalies. These include heightened desensitisation of brain insulin and insulin-like growth factor-1 (IGF-1) reactions, compromised mitochondrial functionality, escalated oxidative stress, reduced autophagy, and the accumulation of amyloid beta and tau phosphorylation. These multifaceted factors intertwine to shape the intricate landscape of DS-related brain pathology. Altered brain insulin signalling is linked to Alzheimer's disease (AD). This disruption may stem from anomalies in the extracellular aspect (insulin receptor) or the intracellular facet, involving the inhibition of insulin receptor substrate 1 (IRS1). Both domains contribute to the intricate mechanism underlying this dysregulation. The PI3K-Akt/mammalian target of the rapamycin (mTOR) axis is a crucial intracellular element of the insulin signalling pathway that connects numerous physiological processes in the cell cycle. In age-related neurodegenerative disorders like AD, aberrant modulation of the PI3K-Akt signalling cascade is a key factor contributing to their onset. Aberrant and sustained hyperactivation of the PI3K/Akt-mTOR axis in the DS brain is implicated in early symptoms of AD development. Targeting the PI3K-Akt/mTOR pathway may help delay the onset of early-onset AD in individuals with DS, offering a potential way to slow disease progression and enhance their quality of life.

The Influence of Circadian Rhythms on DNA Damage Repair in Skin Photoaging

Circadian rhythms, the internal timekeeping systems governing physiological processes, significantly influence skin health, particularly in response to ultraviolet radiation (UVR). Disruptions in circadian rhythms can exacerbate UVR-induced skin damage and increase the risk of skin aging and cancer. This review explores how circadian rhythms affect various aspects of skin physiology and pathology, with a special focus on DNA repair. Circadian regulation ensures optimal DNA repair following UVR-induced damage, reducing mutation accumulation, and enhancing genomic stability. The circadian control over cell proliferation and apoptosis further contributes to skin regeneration and response to UVR. Oxidative stress management is another critical area where circadian rhythms exert influence. Key circadian genes like brain and muscle ARNT-like 1 (BMAL1) and circadian locomotor output cycles kaput (CLOCK) modulate the activity of antioxidant enzymes and signaling pathways to protect cells from oxidative stress. Circadian rhythms also affect inflammatory and immune responses by modulating the inflammatory response and the activity of Langerhans cells and other immune cells in the skin. In summary, circadian rhythms form a complex defense network that manages UVR-induced damage through the precise regulation of DNA damage repair, cell proliferation, apoptosis, inflammatory response, oxidative stress, and hormonal signaling. Understanding these mechanisms provides insights into developing targeted skin protection and improving skin cancer prevention.

Exosomal MicroRNAs modulate the cognitive function in fasudil treated APPswe/PSEN1dE9 transgenic (APP/PS1) mice model of Alzheimer's disease

Alzheimer's disease (AD) is characterized by cognitive decline stemming from the accumulation of beta-amyloid (Aβ) plaques and the propagation of tau pathology through synapses. Exosomes, crucial mediators in neuronal development, maintenance, and intercellular communication, have gained attention in AD research. Yet, the molecular mechanisms involving exosomal miRNAs in AD remain elusive. In this study, we treated APPswe/PSEN1dE9 transgenic (APP/PS1) mice, a model for AD, with either vehicle (ADNS) or fasudil (ADF), while C57BL/6 (control) mice received vehicle (WT). Cognitive function was evaluated using the Y-maze test, and AD pathology was confirmed through immunostaining and western blot analysis of Aβ plaques and phosphorylated tau. Exosomal RNAs were extracted, sequenced, and analyzed from each mouse group. Our findings revealed that fasudil treatment improved cognitive function in AD mice, as evidenced by increased spontaneous alternation in the Y-maze test and reduced Aβ plaque load and phosphorylated tau protein expression in the hippocampus. Analysis of exosomal miRNAs identified three miRNAs (mmu-let-7i-5p, mmu-miR-19a-3p, mmu-miR-451a) common to both ADNS vs ADF and WT vs ADNS groups. Utilizing miRTarBase software, we predicted and analyzed target genes associated with these miRNAs. Gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of miRNA target genes indicated that mmu-miR-19a-3p and mmu-miR-451a are implicated in signal transduction, immune response, cellular communication, and nervous system pathways. Specifically, mmu-miR-19a-3p targeted genes involved in the sphingolipid signaling pathway, such as Pten and Tnf, while mmu-miR-451a targeted Nsmaf, Gnai3, and Akt3. Moreover, mmu-miR-451a targeted Myc in signaling pathways regulating the pluripotency of stem cells. In conclusion, fasudil treatment enhanced cognitive function by modulating exosomal MicroRNAs, particularly mmu-miR-451a and mmu-miR-19a-3p. These miRNAs hold promise as potential biomarkers and therapeutic targets for novel AD treatments.

The effect of intra-nasal co-treatment with insulin and growth factor-rich serum on behavioral defects, hippocampal oxidative-nitrosative stress, and histological changes induced by icv-STZ in a rat model

Impaired insulin and growth factor functions are thought to drive many alterations in neurodegenerative diseases like dementia and seem to contribute to oxidative stress and inflammatory responses. Recent studies revealed that nasal growth factor therapy could induce neuronal and oligodendroglia protection in rodent brain damage induction models. Impairment of several growth factors signaling was reported in neurodegenerative diseases. So, in the present study, we examined the effects of intranasal co-treatment of insulin and a pool of growth factor-rich serum (GFRS) which separated from activated platelets on memory, and behavioral defects induced by intracerebroventricular streptozotocin (icv-STZ) rat model also investigated changes in the hippocampal oxidative-nitrosative state and histology. We found that icv-STZ injection (3 mg/kg bilaterally) impairs spatial learning and memory in Morris Water Maze, leads to anxiogenic-like behavior in the open field arena, and induces oxidative-nitrosative stress, neuroinflammation, and neuronal/oligodendroglia death in the hippocampus. GFRS (1µl/kg, each other day, 9 doses) and regular insulin (4 U/40 µl, daily, 18 doses) treatments improved learning, memory, and anxiogenic behaviors. The present study showed that co-treatment (GFRS + insulin with respective dose) has more robust protection against hippocampal oxidative-nitrosative stress, neuroinflammation, and neuronal/oligodendroglia survival in comparison with the single therapy. Memory and behavioral improvements in the co-treatment of insulin and GFRS could be attributed to their effects on neuronal/oligodendroglia survival and reduction of neuroinflammation in the hippocampus.

Potential role of molecular hydrogen therapy on oxidative stress and redox signaling in chronic kidney disease

Oxidative stress plays a key role in chronic kidney disease (CKD) development and progression, inducing kidney cell damage, inflammation, and fibrosis. However, effective therapeutic interventions to slow down CKD advancement are currently lacking. The multifaceted pharmacological effects of molecular hydrogen (H2) have made it a promising therapeutic avenue. H2 is capable of capturing harmful •OH and ONOO- while maintaining the crucial reactive oxygen species (ROS) involved in cellular signaling. The NRF2-KEAP1 system, which manages cell redox balance, could be used to treat CKD. H2 activates this pathway, fortifying antioxidant defenses and scavenging ROS to counteract oxidative stress. H2 can improve NRF2 signaling by using the Wnt/β-catenin pathway and indirectly activate NRF2-KEAP1 in mitochondria. Additionally, H2 modulates NF-κB activity by regulating cellular redox status, inhibiting MAPK pathways, and maintaining Trx levels. Treatment with H2 also attenuates HIF signaling by neutralizing ROS while indirectly bolstering HIF-1α function. Furthermore, H2 affects FOXO factors and enhances the activity of antioxidant enzymes. Despite the encouraging results of bench studies, clinical trials are still limited and require further investigation. The focus of this review is on hydrogen's role in treating renal diseases, with a specific focus on oxidative stress and redox signaling regulation, and it discusses its potential clinical applications.

Interactions between mitochondrial dysfunction and other hallmarks of aging: Paving a path toward interventions that promote healthy old age

Current research on human aging has largely been guided by the milestone paper "hallmarks of aging," which were first proposed in the seminal 2013 paper by Lopez-Otin et al. Most studies have focused on one aging hallmark at a time, asking whether the underlying molecular perturbations are sufficient to drive the aging process and its associated phenotypes. More recently, researchers have begun to investigate whether aging phenotypes are driven by concurrent perturbations in molecular pathways linked to not one but to multiple hallmarks of aging and whether they present different patterns in organs and systems over time. Indeed, preliminary results suggest that more complex interactions between aging hallmarks must be considered and addressed, if we are to develop interventions that successfully promote healthy aging and/or delay aging-associated dysfunction and diseases. Here, we summarize some of the latest work and views on the interplay between hallmarks of aging, with a specific focus on mitochondrial dysfunction. Indeed, this represents a significant example of the complex crosstalk between hallmarks of aging and of the effects that an intervention targeted to a specific hallmark may have on the others. A better knowledge of these interconnections, of their cause-effect relationships, of their spatial and temporal sequence, will be very beneficial for the whole aging research field and for the identification of effective interventions in promoting healthy old age.

Identification and characterization of long non-coding RNA (lncRNA) in cypermethrin and chlorpyrifos exposed zebrafish (Danio rerio) brain

Pesticides, such as cypermethrin (CYP) and chlorpyrifos (CPF), are widely used around the world and are known to cause toxicological effects in the brains of fish and other non-target organisms. Long non-coding RNAs (LncRNAs) are a new class of non-coding RNAs that are highly expressed in the brain and play crucial roles in brain function by regulating gene expression. Many studies have investigated the toxic effects of CYP and CPF on the brain. However, no study has been conducted on the relationship between LncRNAs and the toxicity caused by these chemicals. Therefore, this study aimed to determine changes in the lncRNA expression profile in the brains of fish exposed to CYP and CPF. Out of a total of 482 lncRNAs that were differentially expressed between control and CPF groups, 53 were found to be up-regulated, and 429 were down-regulated. Similarly, among the 200 lncRNAs differentially expressed between the control and CYP groups, 71 were up-regulated, and 129 were down-regulated. Additionally, 268 differentially expressed lncRNAs were identified between CYP and CPF groups, with 240 being up-regulated and the rest being down-regulated. In addition, LncRNAs expressed from fish brains exposed to CYP and CPF were found to regulate multiple signaling pathways, including MAPK, FoxO, PPAR, TGF-β, and Wnt signaling pathways.

The possible anti-seizure properties of Klotho

Recurrent seizures in epilepsy may lead to progressive neuronal damage, which can diminish health-related quality of life. Evaluation and control of pathological processes in the brain is valuable. It seems imperative that new markers and approaches for seizure alleviation be discovered. Klotho (Kl), an antiaging protein, has protective effects in the brain against neurological disorders. It may also have antiseizure effects by improving creatine transfer to the brain, upregulating excitatory amino acid transporters, and inhibiting insulin/insulin-like growth factor-1 (IGF-1), Wingless (Wnt), transforming growth factor-beta (TGF-β), and retinoic-acid-inducible gene-I (RIG-I)/nuclear translocation of nuclear factor-κB (NF-κB) pathways. Stimulation and activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) and apoptosis signal-regulating kinase 1 (ASK1)/p38 mitogen‑activated protein kinase (MAPK) signaling pathways could also be considered other possible antiseizure mechanisms of Kl. In the present review, the roles of Kl in the central nervous system as well as its possible anti-seizure properties are discussed for the first time.

Identification of oxidative stress-related genes differentially expressed in Alzheimer's disease and construction of a hub gene-based diagnostic model

Alzheimer's disease (AD) is the most prevalent dementia disorder globally, and there are still no effective interventions for slowing or stopping the underlying pathogenic mechanisms. There is strong evidence implicating neural oxidative stress (OS) and ensuing neuroinflammation in the progressive neurodegeneration observed in the AD brain both during and prior to symptom emergence. Thus, OS-related biomarkers may be valuable for prognosis and provide clues to therapeutic targets during the early presymptomatic phase. In the current study, we gathered brain RNA-seq data of AD patients and matched controls from the Gene Expression Omnibus (GEO) to identify differentially expressed OS-related genes (OSRGs). These OSRGs were analyzed for cellular functions using the Gene Ontology (GO) database and used to construct a weighted gene co-expression network (WGCN) and protein-protein interaction (PPI) network. Receiver operating characteristic (ROC) curves were then constructed to identify network hub genes. A diagnostic model was established based on these hub genes using Least Absolute Shrinkage and Selection Operator (LASSO) and ROC analyses. Immune-related functions were examined by assessing correlations between hub gene expression and immune cell brain infiltration scores. Further, target drugs were predicted using the Drug-Gene Interaction database, while regulatory miRNAs and transcription factors were predicted using miRNet. In total, 156 candidate genes were identified among 11046 differentially expressed genes, 7098 genes in WGCN modules, and 446 OSRGs, and 5 hub genes (MAPK9, FOXO1, BCL2, ETS1, and SP1) were identified by ROC curve analyses. These hub genes were enriched in GO annotations "Alzheimer's disease pathway," "Parkinson's Disease," "Ribosome," and "Chronic myeloid leukemia." In addition, 78 drugs were predicted to target FOXO1, SP1, MAPK9, and BCL2, including fluorouracil, cyclophosphamide, and epirubicin. A hub gene-miRNA regulatory network with 43 miRNAs and hub gene-transcription factor (TF) network with 36 TFs were also generated. These hub genes may serve as biomarkers for AD diagnosis and provide clues to novel potential treatment targets.

CDK10, CDK11, FOXO1, and FOXO3 Gene Expression in Alzheimer's Disease Encephalic Samples

Alzheimer's disease (AD) is a progressive neuroinflammatory and neurodegenerative disorder that affects different regions of the brain. Its pathophysiology includes the accumulation of β-amyloid protein, formation of neurofibrillary tangles, and inflammatory processes. Genetic factors are involved in the onset of AD, but they are not fully elucidated. Identification of gene expression in encephalic tissues of patients with AD may help elucidate its development. Our objectives were to characterize and compare the gene expression of CDK10, CDK11, FOXO1, and FOXO3 in encephalic tissue samples from AD patients and elderly controls, from the auditory cortex and cerebellum. RT-qPCR was used on samples from 82 individuals (45 with AD and 37 controls). We observed a statistically significant increase in CDK10 (p = 0.029*) and CDK11 (p = 0.048*) gene expression in the AD group compared to the control, which was most evident in the cerebellum. Furthermore, the Spearman test demonstrated the presence of a positive correlation of gene expression both in the auditory cortex in the AD group (r = 0.046/p = 0.004) and control group (r = 0.454/p = 0.005); and in the cerebellum in the AD group (r = 0.654 /p < 0.001). There was no statistically significant difference and correlation in the gene expression of FOXO1 and FOXO3 in the AD group and the control. In conclusion, CDK10 and CDK11 have high expression in AD patients compared to control, and they present a positive correlation of gene expression in the analyzed groups and tissues, which suggests that they play an important role in the pathogenesis of AD.

Docosahexaenoic acid enhances hippocampal insulin sensitivity to promote cognitive function of aged rats on a high-fat diet

INTRODUCTION

Diminished brain insulin sensitivity is associated with reduced cognitive function. Docosahexaenoic acid (DHA) is known to maintain normal brain function.

OBJECTIVES

This study aimed to determine whether DHA impacts hippocampal insulin sensitivity and cognitive function in aged rats fed a high-fat diet (HFD).

METHODS

Eight-month-old female Sprague-Dawley rats were randomly divided into three groups (n = 50 each). Rats in the aged group, HFD group, and DHA treatment group received standard diet (10 kcal% fat), HFD (45 kcal% fat), and DHA-enriched HFD (45 kcal% fat, 1% DHA, W/W) for 10 months, respectively. Four-month-old female rats (n = 40) that received a standard diet served as young controls. Neuroinflammation, oxidative stress, amyloid formation, and tau phosphorylation in the hippocampus, as well as systemic glucose homeostasis and cognitive function, were tested.

RESULTS

DHA treatment relieved a block in the insulin signaling pathway and consequently protected aged rats against HFD-induced hippocampal insulin resistance. The beneficial effects were explained by a DHA-induced decrease in systemic glucose homeostasis dysregulation, hippocampal neuroinflammation and oxidative stress. In addition, DHA treatment broke the reciprocal cycle of hippocampal insulin resistance, Aβ burden, and tau hyperphosphorylation. Importantly, treatment of model rats with DHA significantly increased their cognitive capacity, as evidenced by their increased hippocampal-dependent learning and memory, restored neuron morphology, enhanced cholinergic activity, and activated cyclic AMP-response element-binding protein.

CONCLUSION

DHA improves cognitive function by enhancing hippocampal insulin sensitivity.

Klotho, Oxidative Stress, and Mitochondrial Damage in Kidney Disease

Reducing oxidative stress stands at the center of a prevention and control strategy for mitigating cellular senescence and aging. Kidney disease is characterized by a premature aging syndrome, and to find a modulator targeting against oxidative stress, mitochondrial dysfunction, and cellular senescence in kidney cells could be of great significance to prevent and control the progression of this disease. This review focuses on the pathogenic mechanisms related to the appearance of oxidative stress damage and mitochondrial dysfunction in kidney disease. In this scenario, the anti-aging Klotho protein plays a crucial role by modulating signaling pathways involving the manganese-containing superoxide dismutase (Mn-SOD) and the transcription factors FoxO and Nrf2, known antioxidant systems, and other known mitochondrial function regulators, such as mitochondrial uncoupling protein 1 (UCP1), B-cell lymphoma-2 (BCL-2), Wnt/β-catenin, peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1 alpha), transcription factor EB, (TFEB), and peroxisome proliferator-activated receptor gamma (PPAR-gamma). Therefore, Klotho is postulated as a very promising new target for future therapeutic strategies against oxidative stress, mitochondria abnormalities, and cellular senescence in kidney disease patients.

Honokiol Microemulsion Causes Stage-Dependent Toxicity Via Dual Roles in Oxidation-Reduction and Apoptosis through FoxO Signaling Pathway

Honokiol, the main bioactive extract of Magnolia officinalis, exhibits extensive therapeutic actions. Its treatment for advanced non-small cell lung cancer is undergoing clinical trials in China. However, the published safety evaluation studies have focused on extract mixtures of Magnolia officinalis in which the honokiol content was well below the reported clinical dose of the honokiol monomer. Therefore, safety assessment of the honokiol monomer is urgently needed. Our previous studies have already demonstrated that a high dose of the honokiol microemulsion (0.6 μg/mL) induces developmental toxicity in rats and zebrafish by inducing oxidative stress. By exploring the relationship between time and toxicity, we found that developmental toxic responses were stage-dependent. They mainly occurred within the first 24 h post fertilization (hpf) especially the first 12 hpf. In zebrafish, low doses of honokiol microemulsion (0.15, 0.21 μg/mL) significantly decreased the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) and increased the mRNA expression of bcl-2. In contrast, high dose (0.6 μg/mL) increased the levels of ROS and MDA, decreased activities and mRNA expression of superoxide dismutase (SOD) and catalase (CAT), and increased mRNA expression of bax, c-jnk, p53 and bim. By acridine orange staining, we found that a high dose of honokiol microemulsion induced apoptosis mainly in zebrafish brain. In rat pheochromocytoma cells (PC12 cells), low doses of the honokiol microemulsion (1, 5, 10 µM) exerted a protective effect against H₂O₂-induced oxidative damage while high doses (≥20 µM) induced oxidative stress, which further confirms the dual effects of honokiol microemulsion on nerve cells. These dual roles of the honokiol microemulsion in oxidation-reduction reactions and apoptosis may be regulated by the forkhead box class O (FoxO) signaling pathway. Due to the potential of developmental toxicity, we recommend that the administration of high dose honokiol microemulsion in pregnant women should be considered with caution.

Targeting the liver in dementia and cognitive impairment: Dietary macronutrients and diabetic therapeutics

Many people living with dementia and cognitive impairment have dysfunctional mitochondrial and insulin-glucose metabolism resembling type 2 diabetes mellitus and old age. Evidence from human trials shows that nutritional interventions and anti-diabetic medicines that target nutrient-sensing pathways overcome these deficits in glucose and energy metabolism and can improve cognition and/or reduce symptoms of dementia. The liver is the main organ that mediates the systemic effects of diets and many diabetic medicines; therefore, it is an intermediate target for such dementia interventions. A challenge is the efficacy of these treatments in older age. Solutions include the targeted hepatic delivery of diabetic medicines using nanotechnologies and titration of macronutrients to optimize hepatic energy metabolism.

Bifidobacterium animalis MSMC83 Improves Oxidative Stress and Gut Microbiota in D-Galactose-Induced Rats

The development of many chronic diseases is associated with an excess of free radicals leading to harmful oxidative stress. Certain probiotic strains have been shown to have antioxidant and anti-aging properties and are an important resource for development of microbial antioxidants. The present study aimed to explore the protection offered by Bifidobacterium animalis strain MSMC83 in a model of oxidative stress induced by D-galactose (D-gal). Male Sprague Dawley rats were randomly allocated to four groups: a control group injected with saline, a group injected subcutaneously with D-galactose, a probiotic group injected with D-galactose and administered B. animalis MSMC83 (109 CFU/mL) via daily oral gavage, and an ascorbic acid group. The probiotics significantly increased the superoxide dismutase, catalase, and glutathione peroxidase and significantly decreased the malondialdehyde in the plasma and livers of D-galactose-treated rats. Moreover, tumor necrosis factor-alpha level in the liver was significantly decreased. Furthermore, the treatment with B. animalis MSMC83 restored the microbiota diversity after D-galactose injection. Therefore, our results supported a beneficial role of B. animalis MSMC83 in alleviating oxidative stress through the increased expression of antioxidant enzymes and reduction of pro-inflammatory cytokines in rats. Our study suggests that B. animalis MSMC83 may be part of a healthy diet to prevent oxidative stress-associated diseases.

Ginsenoside Rg1 improves Alzheimer's disease by regulating oxidative stress, apoptosis, and neuroinflammation through Wnt/GSK-3β/β-catenin signaling pathway

Alzheimer's disease (AD) is a chronic neurodegenerative disorder that can cause cognitive impairment. Ginsenoside Rg1 (Rg1) has a significant neuroprotective effect on animals with memory impairment. However, the mechanism of how Rg1 mediates the Wnt signaling pathway and improves cognitive function by regulating oxidative stress, apoptosis, and neuroinflammation is still unclear. In this study, the spatial memory ability of tree shrews was tested by Morris water maze, the expression levels of amyloid protein (Aβ1-42), ionized calcium-binding adapter molecule 1 (iba-1), nitrotyrosine (NT), and 8-hydroxyguanine (8-OHG) were detected by immunohistochemistry. Subsequently, the activity of catalase (CAT) and the glutathione peroxidase (GSH-Px) was, respectively, measured by the ammonium molybdate method and the 5,5'-dithiobis (2-nitrobenzoic acid). Furthermore, the malondialdehyde (MDA) concentration was determined by the thiobarbituric acid test. Finally, the expression levels of Beta-secretase (BACE1), superoxide dismutase (SOD), BCL2-Associated X (Bax), B-cell lymphoma-2 (Bcl-2), caspase-anti-apoptotic factor Cleaved-caspase-3 (Caspase-3), microtubule-associated proteins 2 (MAP2), Neuronal nuclear antigen (NeuN), as well as the phosphorylation of GSK-3β and β-catenin were detected by Western blot. This study implied that Rg1 reduced the phosphorylation of Tau protein, the deposition of Aβ1-42, and the expression of BACE1. It also showed that Rg1 increased the antioxidant activity of SOD, CAT, GPx, and instead reduced the oxidation products of NT, 8-OHG, and MDA, as wells as the inflammatory factor interleukin-1 and iba-1. It further showed that Rg1 increased the ratio of Bcl-2 to Bax and expression of neuronal markers MAP2 and NeuN, but instead reduced the expression of Caspase-3, GSK-3β, and β-catenin. In conclusion, by regulating the Wnt/GSK-3β/β-catenin signaling pathway, Rg1 of moderate and high dose could alleviate oxidative stress damage, improve neuroinflammation, protect neurons, finally improve the cognitive impairment of the AD tree shrew. This study provides theoretical basis for the Rg1 clinical application in AD.

Down-Regulation of Insulin Like Growth Factor 1 Involved in Alzheimer’s Disease via MAPK, Ras, and FoxO Signaling Pathways

The inability to halt or even delay the course of Alzheimer's disease (AD) forces the development of new molecular signatures and therapeutic strategies. Insulin like growth factor 1 (IGF1) is a promising target for AD treatment, yet exact mechanisms of AD ascribed to IGF1 remain elusive. Herein, gene expression profiles of 195 samples were analyzed and 19,245 background genes were generated, among which 4,424 differentially expressed genes (DEGs) were overlapped between AD/control and IGF1-low/high groups. Based on such DEGs, seven co-expression modules were established by weight gene correlation network analysis (WGCNA). The turquoise module had the strongest correlation with AD and IGF1-low expression, the DEGs of which were enriched in GABAergic synapse, long-term potentiation, mitogen-activated protein kinase (MAPK), Ras, and forkhead box O (FoxO) signaling pathways. Furthermore, cross-talking pathways of IGF1, including MAPK, Ras, and FoxO signaling pathways were identified in the protein-protein interaction network. According to the area under the curve (AUC) analysis, down-regulation of IGF1 exhibited good diagnostic performance in AD prediction. Collectively, our findings highlight the involvement of low IGF1 in AD pathogenesis via MAPK, Ras, and FoxO signaling pathways, which might advance strategies for the prevention and therapy of AD based on IGF1 target.

Small RNA Sequencing in the Tg4–42 Mouse Model Suggests the Involvement of snoRNAs in the Etiology of Alzheimer’s Disease

Background: The Tg4-42 mouse model for sporadic Alzheimer’s disease (AD) has unique features, as the neuronal expression of wild type N-truncated Aβ4–42 induces an AD-typical neurological phenotype in the absence of plaques. It is one of the few models developing neuron death in the CA1 region of the hippocampus. As such, it could serve as a powerful tool for preclinical drug testing and identification of the underlying molecular pathways that drive the pathology of AD. Objective: The aim of this study was to use a differential co-expression analysis approach for analyzing a small RNA sequencing dataset from a well-established murine model in order to identify potentially new players in the etiology of AD. Methods: To investigate small nucleolar RNAs in the hippocampus of Tg4-42 mice, we used RNA-Seq data from this particular tissue and, instead of analyzing the data at single gene level, employed differential co-expression analysis, which takes the comparison to gene pair level and thus affords a new angle to the interpretation of these data. Results: We identified two clusters of differentially correlated small RNAs, including Snord55, Snord57, Snord49a, Snord12, Snord38a, Snord99, Snord87, Mir1981, Mir106b, Mir30d, Mir598, and Mir99b. Interestingly, some of them have been reported to be functionally relevant in AD pathogenesis, as AD biomarkers, regulating tau phosphorylation, TGF-β receptor function or Aβ metabolism. Conclusion: The majority of snoRNAs for which our results suggest a potential role in the etiology of AD were so far not conspicuously implicated in the context of AD pathogenesis and could thus point towards interesting new avenues of research in this field.

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.

Sevoflurane-Induced Apoptosis in the Mouse Cerebral Cortex Follows Similar Characteristics of Physiological Apoptosis

General anesthetics are capable of inducing neuronal apoptosis during the rapid synaptogenesis of immature mammalian brains. In this vulnerable time window, physiological apoptosis also occurs to eliminate excess and inappropriately integrated neurons. We previously showed that physiological and ketamine-induced apoptosis in mouse primary somatosensory cortex (S1) followed similar developmental patterns. However, since sevoflurane is more widely used in pediatric anesthesia, and targets mainly on different receptors, as compared with ketamine, it is important to determine whether sevoflurane-induced apoptosis also follows similar developmental patterns as physiological apoptosis or not. Mice at postnatal days 5 (P5) and P9 were anesthetized with 1.5% sevoflurane for 4 h, and the apoptotic neurons in S1 were quantitated by immunohistochemistry. The results showed that sevoflurane raised the levels of apoptosis in S1 without interfering with the developmental patterns of physiological apoptosis. The cells more vulnerable to both physiological and sevoflurane-induced apoptosis shifted from layer V pyramidal neurons at P5 to layers II–IV GABAergic neurons by P9. The magnitude of both sevoflurane-induced and physiological apoptosis was more attenuated at P9 than P5. To determine whether the Akt-FoxO1-PUMA pathway contributes to the developmental decrease in magnitude of both physiological and sevoflurane-induced apoptosis, Western blot was used to measure the levels of related proteins in S1 of P5 and P9 mice. We observed higher levels of antiapoptotic phosphorylated Akt (p-Akt) and phosphorylated FoxO1 (p-FoxO1), and lower levels of the downstream proapoptotic factor PUMA in control and anesthetized mice at P9 than P5. In addition, the Akt-FoxO1-PUMA pathway may also be responsible for sevoflurane-induced apoptosis. Together, these results suggest that magnitude, lamination pattern and cell-type specificity to sevoflurane-induced apoptosis are age-dependent and follow physiological apoptosis pattern. Moreover, The Akt-FoxO1-PUMA pathway may mediate the developmental decreases in magnitude of both physiological and sevoflurane-induced apoptosis in neonatal mouse S1.

Network pharmacology analysis reveals neuroprotection of Gynostemma pentaphyllum (Thunb.) Makino in Alzheimer' disease

Background

Alzheimer’s disease (AD) is one of the most common neurodegenerative disorders in the world, but still lack of effective drug treatment. Gynostemma Pentaphyllum (Thunb.) Makino (GpM), a Chinese medicinal herb, plays important roles in anti-inflammation, anti-oxidative stress and anti-tumor, which has been reported to ameliorate cognitive impairment of AD. However, the neuroprotective mechanism of GpM remains unclear. This study aims to investigate the targets and possible signaling pathways of GpM in the treatment of AD.

Methods

Active compounds of GpM and their putative target proteins were selected from Traditional Chinese Medicine Systems Pharmacology (TCMSP) Database and Analysis Platform. AD-associated targets were identified from GeneCards, the Online Mendelian Inheritance in Man (OMIM) database and the Therapeutic Target Database (TTD). The intersecting targets of GpM and AD were identified and Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were carried out to analyze the mechanism of them. Compound-target-pathway (CTP) network and protein–protein interaction (PPI) network were constructed and analyzed to elucidate the correlation between compounds, proteins and pathways. Molecular docking was performed to further demonstrate the possibility of GpM for AD.

Results

A total of 13 active compounds of GpM, 168 putative target proteins of compounds and 722 AD-associated targets were identified. Eighteen intersecting targets of GpM and AD were found and the epidermal growth factor receptor (EGFR), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), nitric oxide synthase in endothelial (NOS3) and serum paraoxonase/arylesterase 1 (PON1) were selected as the primary targets of GpM in the treatment of AD. The neuroprotective effect of GPM was related to a variety of pathways, including amoebiasis, HIF-1 signaling pathway, cytokine-cytokine receptor interaction and so on.

Conclusions

Our findings elucidate the active compounds, targets and pathways of GpM involved in effects of anti-AD. The novel mechanism of GpM against AD provides more treatment options for AD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03534-z.

Cross-Talking Pathways of Forkhead Box O1 (FOXO1) Are Involved in the Pathogenesis of Alzheimer’s Disease and Huntington’s Disease

Alzheimer's disease (AD) and Huntington's disease (HD) are destructive worldwide diseases. Efforts have been made to elucidate the process of these two diseases, yet the pathogenesis remains elusive as it involves a combination of multiple factors, including genetic and environmental ones. To explore the potential role of forkhead box O1 (FOXO1) in the development of AD and HD, we identified 1,853 differentially expressed genes (DEGs) from 19,414 background genes in both the AD&HD/control and FOXO1-low/high groups. Four coexpression modules were predicted by the weighted gene coexpression network analysis (WGCNA), among which blue and turquoise modules had the strongest correlation with AD&HD and high expression of FOXO1. Functional enrichment analysis showed that DEGs in these modules were enriched in phagosome, cytokine-cytokine receptor interaction, cellular senescence, FOXO signaling pathway, pathways of neurodegeneration, GABAergic synapse, and AGE-RAGE signaling pathway in diabetic complications. Furthermore, the cross-talking pathways of FOXO1 in AD and HD were jointly determined in a global regulatory network, such as the FOXO signaling pathway, cellular senescence, and AGE-RAGE signaling pathway in diabetic complications. Based on the performance evaluation of the area under the curve of 85.6%, FOXO1 could accurately predict the onset of AD and HD. We then identified the cross-talking pathways of FOXO1 in AD and HD, respectively. More specifically, FOXO1 was involved in the FOXO signaling pathway and cellular senescence in AD; correspondingly, FOXO1 participated in insulin resistance, insulin, and the FOXO signaling pathways in HD. Next, we use GSEA to validate the biological processes in AD&HD and FOXO1 expression. In GSEA analysis, regulation of protein maturation and regulation of protein processing were both enriched in the AD&HD and FOXO1-high groups, suggesting that FOXO1 may have implications in onset and progression of these two diseases through protein synthesis. Consequently, a high expression of FOXO1 is a potential pathogenic factor in both AD and HD involving mechanisms of the FOXO signaling pathway, AGE-RAGE signaling pathway in diabetic complications, and cellular senescence. Our findings provide a comprehensive perspective on the molecular function of FOXO1 in the pathogenesis of AD and HD.

Downregulation of PIK3CB Involved in Alzheimer's Disease via Apoptosis, Axon Guidance, and FoxO Signaling Pathway

OBJECTIVE

To investigate the molecular function of phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit beta (PIK3CB) underlying Alzheimer's disease (AD).

METHODS

RNA sequencing data were used to filtrate differentially expressed genes (DEGs) in AD/nondementia control and PIK3CB-low/high groups. An unbiased coexpression network was established to evaluate module-trait relationships by using weight gene correlation network analysis (WGCNA). Global regulatory network was constructed to predict the protein-protein interaction. Further cross-talking pathways of PIK3CB were identified by functional enrichment analysis.

RESULTS

The mean expression of PIK3CB in AD patients was significantly lower than those in nondementia controls. We identified 2,385 DEGs from 16,790 background genes in AD/control and PIK3CB-low/high groups. Five coexpression modules were established using WGCNA, which participated in apoptosis, axon guidance, long-term potentiation (LTP), regulation of actin cytoskeleton, synaptic vesicle cycle, FoxO, mitogen-activated protein kinase (MAPK), and vascular endothelial growth factor (VEGF) signaling pathways. DEGs with strong relation to AD and low PIK3CB expression were extracted to construct a global regulatory network, in which cross-talking pathways of PIK3CB were identified, such as apoptosis, axon guidance, and FoxO signaling pathway. The occurrence of AD could be accurately predicted by low PIK3CB based on the area under the curve of 71.7%.

CONCLUSIONS

These findings highlight downregulated PIK3CB as a potential causative factor of AD, possibly mediated via apoptosis, axon guidance, and FoxO signaling pathway.

Possible actions of cannabidiol in obsessive-compulsive disorder by targeting the WNT/β-catenin pathway

Obsessive-compulsive disorder (OCD) is a neuropsychiatric disorder characterized by recurrent and distinctive obsessions and/or compulsions. The etiologies remain unclear. Recent findings have shown that oxidative stress, inflammation, and glutamatergic pathways play key roles in the causes of OCD. However, first-line therapies include cognitive-behavioral therapy but only 40% of the patients respond to this first-line therapy. Research for new treatment is mandatory. This review focuses on the potential effects of cannabidiol (CBD), as a potential therapeutic strategy, on OCD and some of the presumed mechanisms by which CBD provides its benefit properties. CBD medication downregulates GSK-3β, the main inhibitor of the WNT/β-catenin pathway. The activation of the WNT/β-catenin could be associated with the control of oxidative stress, inflammation, and glutamatergic pathway and circadian rhythms dysregulation in OCD. Future prospective clinical trials could focus on CBD and its different and multiple interactions in OCD.

Role of FoxO transcription factors in aging and age-related metabolic and neurodegenerative diseases

Aging happens to all of us as we live. Thanks to the improved living standard and discovery of life-saving medicines, our life expectancy has increased substantially across the world in the past century. However, the rise in lifespan leads to unprecedented increases in both the number and the percentage of individuals 65 years and older, accompanied by the increased incidences of age-related diseases such as type 2 diabetes mellitus and Alzheimer’s disease. FoxO transcription factors are evolutionarily conserved molecules that play critical roles in diverse biological processes, in particular aging and metabolism. Their dysfunction is often found in the pathogenesis of many age-related diseases. Here, we summarize the signaling pathways and cellular functions of FoxO proteins. We also review the complex role of FoxO in aging and age-related diseases, with focus on type 2 diabetes and Alzheimer’s disease and discuss the possibility of FoxO as a molecular link between aging and disease risks.

Isoform-Specific Effects of Apolipoprotein E on Hydrogen Peroxide-Induced Apoptosis in Human Induced Pluripotent Stem Cell (iPSC)-Derived Cortical Neurons

Hydrogen peroxide (H₂O₂)-induced neuronal apoptosis is critical to the pathology of Alzheimer's disease (AD) as well as other neurodegenerative diseases. The neuroprotective effects of apolipoprotein (ApoE) isoforms against apoptosis and the underlying mechanism remains controversial. Here, we have generated human cortical neurons from iPSCs and induced apoptosis with H₂O₂. We show that ApoE2 and ApoE3 pretreatments significantly attenuate neuronal apoptosis, whereas ApoE4 has no neuroprotective effect and higher concentrations of ApoE4 even display toxic effect. We further identify that ApoE2 and ApoE3 regulate Akt/FoxO3a/Bim signaling pathway in the presence of H₂O₂. We propose that ApoE alleviates H₂O₂-induced apoptosis in human iPSC-derived neuronal culture in an isoform specific manner. Our results provide an alternative mechanistic explanation on how ApoE isoforms influence the risk of AD onset as well as a promising therapeutic target for diseases involving neuronal apoptosis in the central nervous system.

Physalin B reduces Aβ secretion through down-regulation of BACE1 expression by activating FoxO1 and inhibiting STAT3 phosphorylation

Physalin B (PB), one of the major active steroidal constituents of Solanaceae Physalis plants, has a wide variety of biological activities. We found that PB significantly down-regulated β-amyloid (Aβ) secretion in N2a/APPsw cells. However, the underlying mechanisms are not well understood. In the current study, we investigated the changes in key enzymes involved in β-amyloid precursor protein (APP) metabolism and other APP metabolites by treating N2a/APPsw cells with PB at different concentrations. The results indicated that PB reduced Aβ secretion, which was caused by down-regulation of β-secretase (BACE1) expression, as indicated at both the protein and mRNA levels. Further research revealed that PB regulated BACE1 expression by inducing the activation of forkhead box O1 (FoxO1) and inhibiting the phosphorylation of signal transducer and activator of transcription 3 (STAT3). In addition, the effect of PB on BACE1 expression and Aβ secretion was reversed by treatment with FoxO1 siRNA and STAT3 antagonist S3I-201. In conclusion, these data demonstrated that PB can effectively down-regulate the expression of BACE1 to reduce Aβsecretion by activating the expression of FoxO1 and inhibiting the phosphorylation of STAT3.

Porphyromonas gingivalis (W83) Infection Induces Alzheimer's Disease-Like Pathophysiology in Obese and Diabetic Mice

BACKGROUND

Periodontal disease(s) and metabolic illnesses negatively impact the quality of life and, eventually mental health.

OBJECTIVE

This study investigated the effect of Porphyromonas gingivalis (W83) oral infection on the development of Alzheimer's disease (AD) pathophysiology in a wild-type obese, diabetic (db/db) mouse model.

METHODS

The db/db mice were either orally infected with P. gingivalis and Fusobacterium nucleatum or sham infected for 16 weeks. The presence of amyloid-β (Aβ) and neurofibrillary tangles (NFTs) were assessed using a silver impregnation technique and subsequently by immunohistochemistry for tau and neuroinflammation. The mRNA abundance of a panel of 184 genes was performed using quantitative real-time PCR, and the differentially expressed genes were analyzed by Ingenuity Pathway Analysis.

RESULTS

While no Aβ plaques and NFTs were evident by silver impregnation, immunohistochemistry (glial cell markers) of the P. gingivalis-infected mice tissue sections exhibited neuroinflammation in the form of reactive microglia and astrocytes. Anti-tau immunopositivity, in addition to cells, was prominent in thickened axons of hippocampal CA neurons. The mRNA abundance of crucial genes in the insulin signaling pathway (INSR, IGF1, IRS, IDE, PIK3R, SGK1, GYS, GSK3B, AKT1) were upregulated, potentially exacerbating insulin resistance in the brain by P. gingivalis oral infection. Increased mRNA abundance of several kinases, membrane receptors, transcription factors, and pro-inflammatory mediators indicated hyperactivation of intracellular cascades with potential for tau phosphorylation and Aβ release in the same infection group.

CONCLUSION

P. gingivalis W83 infection of db/db mice provides a disease co-morbidity model with the potential to reproduce AD pathophysiology with induced periodontal disease.

Global Gene Expression Profiling and Transcription Factor Network Analysis of Cognitive Aging in Monozygotic Twins

Cognitive aging is one of the major problems worldwide, especially as people get older. This study aimed to perform global gene expression profiling of cognitive function to identify associated genes and pathways and a novel transcriptional regulatory network analysis to identify important regulons. We performed single transcript analysis on 400 monozygotic twins using an assumption-free generalized correlation coefficient (GCC), linear mixed-effect model (LME) and kinship model and identified six probes (one significant at the standard FDR < 0.05 while the other results were suggestive with 0.18 ≤ FDR ≤ 0.28). We combined the GCC and linear model results to cover diverse patterns of relationships, and meaningful and novel genes like APOBEC3G, H6PD, SLC45A1, GRIN3B, and PDE4D were detected. Our exploratory study showed the downregulation of all these genes with increasing cognitive function or vice versa except the SLC45A1 gene, which was upregulated with increasing cognitive function. Linear models found only H6PD and SLC45A1, the other genes were captured by GCC. Significant functional pathways (FDR < 3.95e-10) such as focal adhesion, ribosome, cysteine and methionine metabolism, Huntington's disease, eukaryotic translation elongation, nervous system development, influenza infection, metabolism of RNA, and cell cycle were identified. A total of five regulons (FDR< 1.3e-4) were enriched in a transcriptional regulatory analysis in which CTCF and REST were activated and SP3, SRF, and XBP1 were repressed regulons. The genome-wide transcription analysis using both assumption-free GCC and linear models identified important genes and biological pathways implicated in cognitive performance, cognitive aging, and neurological diseases. Also, the regulatory network analysis revealed significant activated and repressed regulons on cognitive function.

Role of Microglia in Regulating Cholesterol and Tau Pathology in Alzheimer's Disease

Cholesterol, a principal constituent of the cell membrane, plays a crucial role in the brain by regulating the synaptic transmission, neuronal signaling, as well as neurodegenerative diseases. Defects in the cholesterol trafficking are associated with enhanced generation of hyperphosphorylated Tau and Amyloid-β protein. Tau, a major microtubule-associated protein in the brain, is the key regulator of the mature neuron. Abnormally hyperphosphorylated Tau hampers the major functions related to microtubule assembly by promoting neurofibrillary tangles of paired helical filaments, twisted ribbons, and straight filaments. The observed pathological changes due to impaired cholesterol and Tau protein accumulation cause Alzheimer's disease. Thus, in order to regulate the pathogenesis of Alzheimer's disease, regulation of cholesterol metabolism, as well as Tau phosphorylation, is essential. The current review provides an overview of (1) cholesterol synthesis in the brain, neurons, astrocytes, and microglia; (2) the mechanism involved in modulating cholesterol concentration between the astrocytes and brain; (3) major mechanisms involved in the hyperphosphorylation of Tau and amyloid-β protein; and (4) microglial involvement in its regulation. Thus, the answering key questions will provide an in-depth information on microglia involvement in managing the pathogenesis of cholesterol-modulated hyperphosphorylated Tau protein.

Potential role of cannabidiol in Parkinson's disease by targeting the WNT/β-catenin pathway, oxidative stress and inflammation

Parkinson's disease (PD) is a major neurodegenerative disease (ND), presenting a progressive degeneration of the nervous system characterized by a loss of dopamine in the substantia nigra pars compacta. Recent findings have shown that oxidative stress and inflammation play key roles in the development of PD. However, therapies remain uncertain and research for new treatment is of the utmost importance. This review focuses on the potential effects of using cannabidiol (CBD) as a potential therapeutic strategy for the treatment of PD and on some of the presumed mechanisms by which CBD provides its beneficial properties. CBD medication downregulates GSK-3β, the main inhibitor of the WNT/β-catenin pathway. Activation of the WNT/β-catenin could be associated with the control of oxidative stress and inflammation. Future prospective clinical trials should focus on CBD and its multiple interactions in the treatment of PD.

Cannabidiol and the Canonical WNT/β-Catenin Pathway in Glaucoma

Glaucoma is a progressive neurodegenerative disease which constitutes the main frequent cause of irreversible blindness. Recent findings have shown that oxidative stress, inflammation and glutamatergic pathway play key roles in the causes of glaucoma. Recent studies have shown a down regulation of the WNT/β-catenin pathway in glaucoma, associated with overactivation of the GSK-3β signaling. WNT/β-catenin pathway is mainly associated with oxidative stress, inflammation and glutamatergic pathway. Cannabidiol (CBD) is a non-psychotomimetic phytocannabinoid derived from Cannabis sativa plant which possesses many therapeutic properties across a range of neuropsychiatric disorders. Since few years, CBD presents an increased interest as a possible drug in anxiolytic disorders. CBD administration is associated with increase of the WNT/β-catenin pathway and decrease of the GSK-3β activity. CBD has a lower affinity for CB1 but can act through other signaling in glaucoma, including the WNT/β-catenin pathway. CBD downregulates GSK3-β activity, an inhibitor of WNT/β-catenin pathway. Moreover, CBD was reported to suppress pro-inflammatory signaling and neuroinflammation, oxidative stress and glutamatergic pathway. Thus, this review focuses on the potential effects of cannabidiol, as a potential therapeutic strategy, on glaucoma and some of the presumed mechanisms by which this phytocannabinoid provides its possible benefit properties through the WNT/β-catenin pathway.

The Role of the FOXO1/β2-AR/p-NF-κB p65 Pathway in the Development of Endometrial Stromal Cells in Pregnant Mice under Restraint Stress

Restraint stress causes various maternal diseases during pregnancy. β₂-Adrenergic receptor (β₂-AR) and Forkhead transcription factor class O 1 (FOXO1) are critical factors not only in stress, but also in reproduction. However, the role of FOXO1 in restraint stress, causing changes in the β₂-AR pathway in pregnant mice, has been unclear. The aim of this research was to investigate the β₂-AR pathway of restraint stress and its impact on the oxidative stress of the maternal uterus. In the study, maternal mice were treated with restraint stress by being restrained in a transparent and ventilated device before sacrifice on Pregnancy Day 5 (P5), Pregnancy Day 10 (P10), Pregnancy Day 15 (P15), and Pregnancy Day 20 (P20) as well as on Non-Pregnancy Day 5 (NP5). Restraint stress augmented blood corticosterone (CORT), norepinephrine (NE), and blood glucose levels, while oestradiol (E2) levels decreased. Moreover, restraint stress increased the mRNA levels of the FOXO family, β₂-AR, and even the protein levels of FOXO1 and β₂-AR in the uterus and ovaries. Furthermore, restraint stress increased uterine oxidative stress level. In vitro, the protein levels of FOXO1 were also obviously increased when β₂-AR was activated in endometrial stromal cells (ESCs). In addition, phosphorylated-nuclear factor kappa-B p65 (p-NF-κB p65) and its target genes decreased significantly when FOXO1 was inhibited. Overall, it can be said that the β₂-AR/FOXO1/p-NF-κB p65 pathway was activated when pregnant mice were under restraint stress. This study provides a scientific basis for the origin of psychological stress in pregnant women.

Parkinson's Disease: Potential Actions of Lithium by Targeting the WNT/β-Catenin Pathway, Oxidative Stress, Inflammation and Glutamatergic Pathway

Parkinson's disease (PD) is one of the major neurodegenerative diseases (ND) which presents a progressive neurodegeneration characterized by loss of dopamine in the substantia nigra pars compacta. It is well known that oxidative stress, inflammation and glutamatergic pathway play key roles in the development of PD. However, therapies remain uncertain and research for new treatment is mandatory. This review focuses on the potential effects of lithium, as a potential therapeutic strategy, on PD and some of the presumed mechanisms by which lithium provides its benefit properties. Lithium medication downregulates GSK-3beta, the main inhibitor of the WNT/β-catenin pathway. The stimulation of the WNT/β-catenin could be associated with the control of oxidative stress, inflammation, and glutamatergic pathway. Future prospective clinical trials could focus on lithium and its different and multiple interactions in PD.

Alzheimer's Disease and Protein Kinases

Alzheimer's disease (AD) is the most common neurodegenerative disorder and accounts for more than 60-80% of all cases of dementia. Loss of pyramidal neurons, extracellular amyloid beta (Abeta) accumulated senile plaques, and neurofibrillary tangles that contain hyperphosphorylated tau constitute the main pathological alterations in AD.Synaptic dysfunction and extrasynaptic N-methyl-D-aspartate receptor (NMDAR) hyperactivation contributes to excitotoxicity in patients with AD. Amyloid precursor protein (APP) and Abeta promoted neurodegeneration develop through the activation of protein kinase signaling cascade in AD. Furthermore, ultimate neuronal death in AD is under control of protein kinases-related signaling pathways. In this chapter, critical check-points within the cross-talk between neuron and protein kinases have been defined regarding the initiation and progression of AD. In this context, amyloid cascade hypothesis, neuroinflammation, oxidative stress, granulovacuolar degeneration, loss of Wnt signaling, Abeta-related synaptic alterations, prolonged calcium ions overload and NMDAR-related synaptotoxicity, damage signals hypothesis and type-3 diabetes are discussed briefly.In addition to clinical perspective of AD pathology, recommendations that might be effective in the treatment of AD patients have been reviewed.

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.

Obesity May Connect Insulin Resistance to Decreased Neuronal Viability in Human Diabetic Brain

OBJECTIVE

This study aimed to investigate the relationship between insulin resistance and markers of neuronal viability and energy metabolism, as well as the additive effects of overweight or obesity, in individuals with type 2 diabetes mellitus (T2DM).

METHODS

Using ¹ H-magnetic resonance spectroscopy, prefrontal N-acetyl aspartate (NAA) and creatine levels, markers for neuronal viability and energy metabolism, respectively, were measured in 50 adults with overweight or obesity and T2DM (T2DM-O; aged 49.0 ± 7.4 years; 50% female), 50 adults with normal weight and T2DM (T2DM-N), and 50 healthy adults with normal weight (healthy-control [HC] group) matched for age and sex. The homeostatic model assessment for insulin resistance levels were calculated to assess insulin resistance.

RESULTS

Prefrontal NAA levels were lower in the T2DM-O group relative to the HC group (t = -2.51, P = 0.013). Higher insulin resistance was associated with lower prefrontal NAA levels in the T2DM-O group (t = -2.21, P = 0.032) but not in the T2DM-N group (t = -0.72, P = 0.48). Prefrontal creatine levels did not differ across the three groups.

CONCLUSIONS

Overweight and obesity might contribute to T2DM-related neuronal viability deficits and could be the key links that connect insulin resistance to the decreased neuronal viability in the human diabetic brain.

FoxO1 overexpression reduces Aβ production and tau phosphorylation in vitro

Forkhead box O1 (FoxO1), a key molecule in the regulation of cell growth, differentiation and metabolism, is an important transcription factor. However, the effect of FoxO1 on Alzheimer's disease (AD) needs further investigation. In this study, we aimed to explore the function and mechanism of FoxO1 in amyloid-β (Aβ) production and tau phosphorylation in AD. First, compared with the age matched wild-type (WT) mice, we showed that FoxO1 protein levels were reduced in the cortices but nearly unchanged in the hippocampi of 6-month-old APPswe/PSEN1dE9 transgenic mice expressing Swedish APP and Presenilin1 delta exon 9 mutations (APP/PS1 mice). Then, we found that overexpression of FoxO1 significantly attenuated Aβ production through inhibiting the amyloidogenic processing of β-amyloid precursor protein (APP), mediated by the key enzymes BACE1 and PS1, in N2a/APPsw cells. Furthermore, in FoxO1-overexpressing HEK293/Tau cells, the decreased levels of tau phosphorylation at selective sites (S262 and T231) were accompanied by increasing the expression of p-GSK-3β (S9), and reducing p-ERK. In contrast, the total tau (Tau-5), non-phosphorylated tau (Tau-1), p-Tau (S404), CDK5 and PP2A levels remained unchanged. These findings indicate that FoxO1 is related to AD and suggest FoxO1 as a therapeutic target for AD that reduces the levels of both Aβ expression and tau phosphorylation.

Alogliptin: a novel approach against cyclophosphamide-induced hepatic injury via modulating SIRT1/FoxO1 pathway

Cyclophosphamide (CP) is one of the most potent alkylating agents and is widely used in the treatment of numerous neoplastic conditions, autoimmune diseases and following organ transplantation. Due to its ability to induce oxidative stress and subsequent apoptosis, CP is affiliated with many adverse effects with special emphasis on the highly prevalent hepatotoxicity. Dipeptidyl peptidase 4 (DDP-IV) inhibitors are being rediscovered for new biological effects due to their ability to target multiple pathways, among which is the phosphoinositide 3-kinase (PI3K) and protein kinase B (Akt) axis. This could offer protection to multiple organs against reactive oxygen species (ROS) through modulating sirtuin 1 (SIRT1) expression and, in turn, inactivation of forkhead box transcription factor of the O class 1 (FoxO1), thus inhibiting apoptosis. Accordingly, the current study aimed to investigate the potential therapeutic benefit of alogliptin (Alo), a DPP-IV inhibitor, against CP-induced hepatotoxicity through enhancing PI3K/Akt/SIRT1 pathway. Forty male Wistar rats were randomly divided into four groups. The CP-treated group received a single dose of CP (200 mg/kg; i.p.). The Alo-treated group received Alo (20 mg/kg; p.o.) for 7 days with single CP injection on Day 2. Alo successfully reduced hepatic injury as witnessed through decreased liver function enzymes, increased phospho (p)-PI3K, p-Akt, superoxide dismutase (SOD) levels, SIRT1 expression, p-FoxO1 and anti-apoptotic B-cell lymphoma 2 (Bcl-2). This resulted in decreased apoptosis, as witnessed through decreased caspase-3 levels and improved histopathological picture. In conclusion, the current study succeeded to elaborate, for the first time, the promising impact of Alo in ameliorating chemotherapy-induced liver injury.

Evaluation of Insulin Resistance Induced Brain Tissue Dysfunction in Obese Dams and their Neonates: Role of Ipriflavone Amelioration

BACKGROUND

Nonalcoholic steatohepatitis (NASH) is associated with activation of liver fibrogenesis and predisposes to cirrhosis and associated morbi-mortality. A high fat high cholesterol diet (HFD) was provided to female albino rats to establish a NASH model. It is well known that the offspring of obese mothers have an increased risk of obesity and diabetes. The present study aimed at evaluating the ameliorative effects of ipriflavone (IP) as a natural food supplement on lipid metabolism, improving insulin sensitivity, reducing oxidative stress and inflammation, modifying metabolic risk factors and/or reduce brain damage, in both neonates and their dams.

MATERIALS AND METHODS

The present aim was achieved by evaluating the oxidative stress and antioxidant defense system biomarkers, as thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH), catalase, and superoxide dismutase (SOD) activities. In addition, the neurotransmitter acetylcholine (Ach) and acetylcholine esterase (AchE) activities, as well as levels of the apolipoprotein E4 (APOE4); β-secretase, hyper phosphor-tau and β-amyloid 42; 3-hydroxy- 3-methyl glutaryl coenzyme A reductase (HMG CoA R)" and COX-II by immunoblotting assays in the brain tissue of neonates and their dams in all the studied groups.

RESULTS

A very significant amelioration in acetylcholine and acetylcholine esterase neurotransmitters, Alzheimer's makers (β-amyloid), antioxidants (reduced glutathione (GSH) contents, catalase (CAT) and superoxide dismutase (SOD); and inflammatory cytokines in NASH model is observed upon administrating ipriflavone (IP) as a natural food supplement. The multifunctional activities of ipriflavone as an antioxidant, anti-inflammatory and anti-insulin resistance drug were discussed and correlated with other investigations.

CONCLUSION

Regarding steatohepatitis, the present study confirmed the anti-inflammatory effects of the ipriflavone (IP). Therefore, future studies should focus on hepatic fatty acid uptake, hepatic lipogenesis, and fatty acid oxidation and the role of IP in regulating hepatic fat metabolism. In addition, natural products like IP could be combined with the highly used pharmaceutical drugs to reduce the side effects of nonalcoholic steatohepatitis, and minimize progression of dementia. Moreover, the present study supports further attempts to heal the neural dysfunction via antioxidant and anti-inflammatory cascade activities using ipriflavone (IP).

TGF-β1 enhances FOXO3 expression in human synovial fibroblasts by inhibiting miR-92a through AMPK and p38 pathways

Osteoarthritis (OA) is an age-related disease marked by synovial inflammation and cartilage destruction arising from synovitis, joint swelling and pain. OA therapy that targets the synovium is a promising strategy for mitigating the symptoms and disease progression. Altered activity of the transforming growth factor-β1 isoform (TGF-β1) during aging underlies OA progression. Notably, aberrant forkhead box class O 3 (FOXO3) activity is implicated in the pathogenesis of various age-related diseases, including OA. This study explored the interaction and cross-talk of TGF-β1 and FOXO3 in human osteoarthritis synovial fibroblasts (OASFs). TGF-β1 stimulated FOXO3 synthesis in OASFs, which was mitigated by blocking adenosine monophosphate-activated protein kinase (AMPK) and p38 activity. TGF-β1 also inhibited the expression of miR-92a, which suppresses FOXO3 transcription. The suppression of miR-92a was effectively reversed with the blockade of the AMPK and p38 pathways. Our study showed that TGF-β1 promotes anti-inflammatory FOXO3 expression by stimulating the phosphorylation of AMPK and p38 and suppressing the downstream expression of miR-92a. These results may help to clarify OA pathogenesis and lead to better targeted treatment.

Central and Peripheral Metabolic Defects Contribute to the Pathogenesis of Alzheimer's Disease: Targeting Mitochondria for Diagnosis and Prevention

Significance: Epidemiological studies indicate that metabolic disorders are associated with an increased risk for Alzheimer's disease (AD). Metabolic remodeling occurs in the central nervous system (CNS) and periphery, even in the early stages of AD. Mitochondrial dysfunction has been widely accepted as a molecular mechanism underlying metabolic disorders. Therefore, focusing on early metabolic changes, especially from the perspective of mitochondria, could be of interest for early AD diagnosis and intervention. Recent Advances: We and others have identified that the levels of several metabolites are fluctuated in the periphery before their accumulation in the CNS, which plays an important role in the pathogenesis of AD. Mitochondrial remodeling is likely one of the earliest signs of AD, linking nutritional imbalance to cognitive deficits. Notably, by improving mitochondrial function, mitochondrial nutrients efficiently rescue cellular metabolic dysfunction in the CNS and periphery in individuals with AD. Critical Issues: Peripheral metabolic disorders should be intensively explored and evaluated for the early diagnosis of AD. The circulating metabolites derived from mitochondrial remodeling represent novel potential diagnostic biomarkers for AD that are more readily detected than CNS-oriented biomarkers. Moreover, mitochondrial nutrients provide a promising approach to preventing and delaying AD progression. Future Directions: Abnormal mitochondrial metabolism in the CNS and periphery is involved in AD pathogenesis. More clinical studies provide evidence for the suitability and reliability of circulating metabolites and cytokines for the early diagnosis of AD. Targeting mitochondria to rewire cellular metabolism is a promising approach to preventing AD and ameliorating AD-related metabolic disorders.

[Selenium and zinc: "antioxidants" for healthy aging?]

Selenium and zinc are essential trace elements and an inadequate dietary intake has been implicated in the decline of immune and cognitive functions in aged persons and in the pathogenesis of age-related disorders. Both micronutrients are often marketed as "antioxidants" in mineral supplements; however, neither selenium nor zinc are antioxidants per se but they may exert beneficial effects as components of enzymes and other proteins that catalyze redox reactions and/or are involved in the maintenance of redox homeostasis. According to epidemiological data older individuals have an increased risk of developing deficiencies in the selenium and zinc status; however, such statistical correlations in epidemiological studies do not imply a causal association. Intervention trials are scarce and have yielded inconsistent and sometimes even adverse results. It should also be noted that the observed deficiencies in micronutrients may not necessarily be attributable to inadequate dietary intake as the absorption and distribution within the body might also be influenced by factors such as medications or interaction with other food ingredients. Thus, any dietary supplementation should be implemented with caution and persons who wish to take mineral supplements should first seek medical advice. This article discusses the role of selenium and zinc in biological antioxidant systems, summarizes findings on the supply and supplementation of aged persons with these trace elements and on the influence they may exert on aging-related health issues, such as cognitive decline and type 2 diabetes mellitus.

Riluzole: a therapeutic strategy in Alzheimer's disease by targeting the WNT/β-catenin pathway

Alzheimer's disease (AD) is a neurodegenerative disease, where the etiology remains unclear. AD is characterized by amyloid-(Aβ) protein aggregation and neurofibrillary plaques deposits. Oxidative stress and chronic inflammation have been suggested as causes of AD. Glutamatergic pathway dysregulation is also mainly associated with AD process. In AD, the canonical WNT/β-catenin pathway is downregulated. Downregulation of WNT/β-catenin, by activation of GSK-3β-induced Aβ, and inactivation of PI3K/Akt pathway involve oxidative stress in AD. The downregulation of the WNT/β-catenin pathway decreases the activity of EAAT2, the glutamate receptors, and leads to neuronal death. In AD, oxidative stress, neuroinflammation and glutamatergic pathway operate in a vicious circle driven by the dysregulation of the WNT/β-catenin pathway. Riluzole is a glutamate modulator and used as treatment in amyotrophic lateral sclerosis. Recent findings have highlighted its use in AD and its potential increase power on the WNT pathway. Nevertheless, the mechanism by which Riluzole can operate in AD remains unclear and should be better determine. The focus of our review is to highlight the potential action of Riluzole in AD by targeting the canonical WNT/β-catenin pathway to modulate glutamatergic pathway, oxidative stress and neuroinflammation.

Epigenetic impact of the social and physical environment on brain and body

Modern biomedical scientists are often trapped in silos of knowledge and practice, such as those who study brain structure, function and behavior, on the one hand, and body systems and disorders, on the other. Scientists and physicians in each of those silos have not often paid attention to the brain-body communication that leads to multi-morbidity of systemic and brain-related disorders [eg. depression with diabetes or cardiovascular disease]. Outside of biomedicine, social scientists have long recognized the impact of the social and physical environment on individuals and populations but have not usually connected these effects with changes in underlying biology. However, with the rise of epigenetics, science and the public understanding of science is leaving an era in which the DNA sequence was thought to be "destiny" and entering an era where the environment shapes the biology and behavior of individuals and groups through its interactive effects on brain and body. It does so, at least in part, by shaping epigenetically the structure and function of brain and body systems that show a considerable amount of adaptive plasticity throughout development and adult life. This results in substantial individual differences even between identical twins. These individual differences are produced epigenetically by the two-way interaction between the brain and hormones, immune system mediators and the autonomic nervous system. Disorders, then, are often multimorbid involving both brain and body, such as depression with diabetes and cardiovascular disease. It is therefore imperative to incorporate into "precision medicine" a better understanding of how these differences affect the efficacy of pharmacological, behavioral and psychosocial interventions. This article presents an overview of this new synthesis, using as an example emerging evidence about the linkages between systemic inflammation, insulin resistance and mental health and neurodegenerative diseases.

Gingko biloba Extract (EGb) Inhibits Oxidative Stress in Neuro 2A Cells Overexpressing APPsw

Alzheimer's disease (AD) is a common neurodegenerative disease. Abundant evidence demonstrates that oxidative stress may be not only an early event in this disease, but also a key factor in the pathogenesis of AD. Ginkgo biloba extract (EGb) has a strong ability to scavenge oxygen free radicals and supply hydrogen. The present study aims to investigate the effects of EGb on Neuro 2A cells transfected with Swedish mutant APP (APPsw). Stably transfected Neuro 2A cell lines expressing human wild-type APP (APP695), APPsw, or empty vector(neo) pEGFP-N2 were treated with 100 μg/ml EGb for 0, 2, 4, 6, 8, and 10 h. Oxidative stress was assessed by measuring free radicals and the activities of antioxidant enzymes. Our studies showed that EGb treatment reduced the production of reactive oxygen species (ROS) and the levels of malondialdehyde (MDA) significantly while total superoxide dismutase (T-SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities were enhanced in Neuro 2A cells overexpressing APPsw. Meanwhile, Aβ levels in these cells were also reduced compared to the levels in untreated cells and control cells (empty vector(neo) pEGFP-N2). These findings suggest that EGb can reduce oxidative stress by decreasing free radical and enhancing antioxidant status, further leading to reduced Aβ aggregation; EGb might be a potential therapeutic agent for Alzheimer's disease (AD).

Neuroprotective Effects of Ferruginol, Jatrophone, and Junicedric Acid Against Amyloid-β Injury in Hippocampal Neurons

Soluble amyloid-β (Aβ) oligomers have been recognized as early neurotoxic intermediates with a key role in the synaptic dysfunction observed in Alzheimer's disease (AD). Aβ oligomers block hippocampal long-term potentiation (LTP) and impair rodent spatial memory. Additionally, the presence of Aβ oligomers is associated with imbalanced intracellular calcium levels and apoptosis in neurons. In this context, we evaluated the effects of three diterpenes (ferruginol, jatrophone, and junicedric acid) that are found in medicinal plants and have several forms of biological activity. The intracellular calcium levels in hippocampal neurons increased in the presence of ferruginol, jatrophone, and junicedric acid, a result that was consistent with the observed increase in CA1 synaptic transmission in mouse hippocampal slices. Additionally, assays using Aβ peptide demonstrated that diterpenes, particularly ferruginol, restore LTP and reduce apoptosis. Recovery of the Aβ oligomer-induced loss of the synaptic proteins PSD-95, synapsin, VGlut, and NMDA receptor subunit 2A was observed in mouse hippocampal slices treated with junicedric acid. This cascade of events may be associated with the regulation of kinases, e.g., protein kinase C (PKC) and calcium/calmodulin-dependent protein kinase II (CaMKII), in addition to the activation of the canonical Wnt signaling pathway and could thus provide protection against Aβ oligomers, which trigger synaptic dysfunction. Our results suggest a potential neuroprotective role for diterpenes against the Aβ oligomers-induced neurodegenerative alterations, which make them interesting molecules to be further studied in the context of AD.

The Role of Insulin-Like Growth Factors and Insulin-Like Growth Factor-Binding Proteins in the Nervous System

The insulin-like growth factors (IGF-I and IGF-II) and their receptors are widely expressed in nervous tissue from early embryonic life. They also cross the blood brain barriers by active transport, and their regulation as endocrine factors therefore differs from other tissues. In brain, IGFs have paracrine and autocrine actions that are modulated by IGF-binding proteins and interact with other growth factor signalling pathways. The IGF system has roles in nervous system development and maintenance. There is substantial evidence for a specific role for this system in some neurodegenerative diseases, and neuroprotective actions make this system an attractive target for new therapeutic approaches. In developing new therapies, interaction with IGF-binding proteins and other growth factor signalling pathways should be considered. This evidence is reviewed, gaps in knowledge are highlighted, and recommendations are made for future research.

Ozone Atmospheric Pollution and Alzheimer's Disease: From Epidemiological Facts to Molecular Mechanisms

Atmospheric pollution is a well-known environmental hazard, especially in developing countries where millions of people are exposed to airborne pollutant levels above safety standards. Accordingly, several epidemiological and animal studies confirmed its role in respiratory and cardiovascular pathologies and identified a strong link between ambient air pollution exposure and adverse health outcomes such as hospitalization and mortality. More recently, the potential deleterious effect of air pollution inhalation on the central nervous system was also investigated and mounting evidence supports a link between air pollution exposure and neurodegenerative pathologies, especially Alzheimer's disease (AD). The focus of this review is to highlight the possible link between ozone air pollution exposure and AD incidence. This review's approach will go from observational and epidemiological facts to the proposal of molecular mechanisms. First, epidemiological and postmortem human study data concerning residents of ozone-severely polluted megacities will be presented and discussed. Then, the more particular role of ozone air pollution in AD pathology will be described and evidenced by toxicological studies in rat or mouse with ozone pollution exposure only. The experimental paradigms used to reproduce in rodent the human exposure to ozone air pollution will be described. Finally, current insights into the molecular mechanisms through which ozone inhalation can affect the brain and play a role in AD development or progression will be recapitulated.