Nuclear Factor-Kappa B and Alzheimer Disease, Unifying Genetic and Environmental Risk Factors from Cell to Humans

The regulating effect of curcumin on NF-κB pathway in neurodegenerative diseases: a review of the underlying mechanisms

Neurodegenerative diseases are part of the central nervous system (CNS) disorders that indicate their presence with neuronal loss, neuroinflammation, and increased oxidative stress. Several pathophysiological factors and biomarkers are involved in this inflammatory process causing these neurological disorders. The nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is an inflammation element, which induced transcription and appears to be one of the important players in physiological procedures, especially nervous disorders. NF-κB can impact upon series of intracellular actions and induce or inhibit many inflammation-related pathways. Multiple reports have focused on the modification of NF-κB activity, controlling its expression, translocation, and signaling pathway in neurodegenerative disorders and injuries like Alzheimer's disease (AD), spinal cord injuries (SCI), and Parkinson's disease (PD). Curcumin has been noted to be a popular anti-oxidant and anti-inflammatory substance and is the foremost natural compound produced by turmeric. According to various studies, when playing an anti-inflammatory role, it interacts with several modulating proteins of long-standing disease signaling pathways and has an unprovocative consequence on pro-inflammatory cytokines. This review article determined to figure out curcumin's role in limiting the promotion of neurodegenerative disease via influencing the NF-κB signaling route. Preclinical studies were gathered from plenty of scientific platforms including PubMed, Scopus, Cochrane, and Google Scholar to evaluate this hypothesis. Extracted findings from the literature review explained the repressing impact of Curcumin on the NF-κB signaling pathway and, occasionally down-regulating the cytokine expression. Yet, there is an essential need for further analysis and specific clinical experiments to fully understand this subject.

Ropinirole reverses the effects of neuroinflammation, and cellular demise by downregulating the MARK4-NFκβ signaling system in Alzheimer's disease

Ropinirole (ROP) is a dopamine agonist that can cross the blood-brain barrier (BBB), which is crucial for drugs targeting neurological conditions like Alzheimer's disease (AD). The rationale for the current research is to investigate the potential of ROP as an inhibitor of Microtubule affinity regulating kinase 4 (MARK4)-NFκβ in neurodegenerative diseases, specifically AD. The interaction between ROP and MARK4-NFκβ holds significant promise in the realm of drug discovery and therapeutic interventions for diseases like AD. Molecular docking and biophysical characterization demonstrate how ROP effectively hinders MARK4 activity, offering detailed insights into their molecular interactions. The present research also investigates the biological aspect of MARK4 shows promise in treating AD, with neuroinflammation playing a crucial role in the disease's progression. Aβ42 and ROP were co-administered directly into the cells for the establishment of the AD model. We confirmed that ROP can inhibit the path of MARK4 activity, as evidenced by biophysical characterization, and can enhance the cell viability, lowers the expression of MARK4, decrease the rate of oxidative stress, and attenuate the expression of NFκβ, leading to reduced neuronal apoptosis in an in vitro-induced Aβ model. Overall, this research provides valuable mechanistic insights into the neuroprotective potential of ROP and its ability to target the MARK4-NFκβ pathway.

Ribonucleotide reductase inhibition improves the symptoms of a Caenorhabditis elegans model of Alzheimer's disease

Alzheimer's disease is the main cause of aging-associated dementia, for which there is no effective treatment. In this work, we reanalyze the information of a previous genome wide association study, using a new pipeline design to identify novel potential drugs. With this approach, ribonucleoside-diphosphate reductase gene (RRM2B) emerged as a candidate target and its inhibitor, 2', 2'-difluoro 2'deoxycytidine (gemcitabine), as a potential pharmaceutical drug against Alzheimer's disease. We functionally verified the effect of inhibiting the RRM2B homolog, rnr-2, in an Alzheimer's model of Caenorhabditis elegans, which accumulates human Aβ1-42 peptide to an irreversible paralysis. RNA interference against rnr-2 and also treatment with 200 ng/ml of gemcitabine, showed an improvement of the phenotype. Gemcitabine treatment increased the intracellular ATP level 3.03 times, which may point to its mechanism of action. Gemcitabine has been extensively used in humans for cancer treatment but at higher concentrations. The 200 ng/ml concentration did not exert a significant effect over cell cycle, or affected cell viability when assayed in the microglia N13 cell line. Thus, the inhibitory drug of the RRM2B activity could be of potential use to treat Alzheimer's disease and particularly gemcitabine might be considered as a promising candidate to be repurposed for its treatment.

Genetic overlap between Alzheimer's disease and immune-mediated diseases: an atlas of shared genetic determinants and biological convergence

The occurrence of immune disease comorbidities in Alzheimer's disease (AD) has been observed in both epidemiological and molecular studies, suggesting a neuroinflammatory basis in AD. However, their shared genetic components have not been systematically studied. Here, we composed an atlas of the shared genetic associations between 11 immune-mediated diseases and AD by analyzing genome-wide association studies (GWAS) summary statistics. Our results unveiled a significant genetic overlap between AD and 11 individual immune-mediated diseases despite negligible genetic correlations, suggesting a complex shared genetic architecture distributed across the genome. The shared loci between AD and immune-mediated diseases implicated several genes, including GRAMD1B, FUT2, ADAMTS4, HBEGF, WNT3, TSPAN14, DHODH, ABCB9, and TNIP1, all of which are protein-coding genes and thus potential drug targets. Top biological pathways enriched with these identified shared genes were related to the immune system and cell adhesion. In addition, in silico single-cell analyses showed enrichment of immune and brain cells, including neurons and microglia. In summary, our results suggest a genetic relationship between AD and the 11 immune-mediated diseases, pinpointing the existence of a shared however non-causal genetic basis. These identified protein-coding genes have the potential to serve as a novel path to therapeutic interventions for both AD and immune-mediated diseases and their comorbidities.

Neurodegenerative effects of air pollutant Particles: Biological mechanisms implicated for Early-Onset Alzheimer's disease

BACKGROUND

Sporadic Alzheimer's disease (AD) occurs in 99% of all cases and can be influenced by air pollution such as diesel emissions and more recently, an iron oxide particle, magnetite, detected in the brains of AD patients. However, a mechanistic link between air pollutants and AD development remains elusive.

AIM

To study the development of AD-relevant pathological effects induced by air pollutant particle exposures and their mechanistic links, in wild-type and AD-predisposed models.

METHODS

C57BL/6 (n = 37) and APP/PS1 transgenic (n = 38) mice (age 13 weeks) were exposed to model pollutant iron-based particle (Fe0-Fe3O4, dTEM = 493 ± 133 nm), hydrocarbon-based diesel combustion particle (43 ± 9 nm) and magnetite (Fe3O4, 153 ± 43 nm) particles (66 µg/20 µL/third day) for 4 months, and were assessed for behavioural changes, neuronal cell loss, amyloid-beta (Aβ) plaque, immune response and oxidative stress-biomarkers. Neuroblastoma SHSY5Y (differentiated) cells were exposed to the particles (100 μg/ml) for 24 h, with assessments on immune response biomarkers and reactive oxygen species generation.

RESULTS

Pollutant particle-exposure led to increased anxiety and stress levels in wild-type mice and short-term memory impairment in AD-prone mice. Neuronal cell loss was shown in the hippocampal and somatosensory cortex, with increased detection of Aβ plaque, the latter only in the AD-predisposed mice, with the wild-type not genetically disposed to form the plaque. The particle exposures however, increased AD-relevant immune system responses, including inflammation, in both strains of mice. Exposures also stimulated oxidative stress, although only observed in wild-type mice. The in vitro studies complemented the immune response and oxidative stress observations.

CONCLUSIONS

This study provides insights into the mechanistic links between inflammation and oxidative stress to pollutant particle-induced AD pathologies, with magnetite apparently inducing the most pathological effects. No exacerbation of the effects was observed in the AD-predisposed model when compared to the wild-type, indicating a particle-induced neurodegeneration that is independent of disease state.

Multi-cohort cerebrospinal fluid proteomics identifies robust molecular signatures for asymptomatic and symptomatic Alzheimer's disease

Changes in Amyloid-β (A), hyperphosphorylated Tau (T) in brain and cerebrospinal fluid (CSF) precedes AD symptoms, making CSF proteome a potential avenue to understand the pathophysiology and facilitate reliable diagnostics and therapies. Using the AT framework and a three-stage study design (discovery, replication, and meta-analysis), we identified 2,173 proteins dysregulated in AD, that were further validated in a third totally independent cohort. Machine learning was implemented to create and validate highly accurate and replicable (AUC>0.90) models that predict AD biomarker positivity and clinical status. These models can also identify people that will convert to AD and those AD cases with faster progression. The associated proteins cluster in four different protein pseudo-trajectories groups spanning the AD continuum and were enrichment in specific pathways including neuronal death, apoptosis and tau phosphorylation (early stages), microglia dysregulation and endolysosomal dysfuncton(mid-stages), brain plasticity and longevity (mid-stages) and late microglia-neuron crosstalk (late stages).

Genetic Factors and Long-term Treatment-Related Neurocognitive Deficits, Anxiety, and Depression in Childhood Leukemia Survivors: An Exome-Wide Association Study

BACKGROUND

An increased risk of neurocognitive deficits, anxiety, and depression has been reported in childhood cancer survivors.

METHODS

We analyzed associations of neurocognitive deficits, as well as anxiety and depression, with common and rare genetic variants derived from whole-exome sequencing data of acute lymphoblastic leukemia (ALL) survivors from the PETALE cohort. In addition, significant associations were assessed using stratified and multivariable analyses. Next, top-ranking common associations were analyzed in an independent SJLIFE replication cohort of ALL survivors.

RESULTS

Significant associations were identified in the entire discovery cohort (N = 229) between the AK8 gene and changes in neurocognitive function, whereas PTPRZ1, MUC16, TNRC6C-AS1 were associated with anxiety. Following stratification according to sex, the ZNF382 gene was linked to a neurocognitive deficit in males, whereas APOL2 and C6orf165 were associated with anxiety and EXO5 with depression. Following stratification according to prognostic risk groups, the modulatory effect of rare variants on depression was additionally found in the CYP2W1 and PCMTD1 genes. In the replication SJLIFE cohort (N = 688), the male-specific association in the ZNF382 gene was not significant; however, a P value<0.05 was observed when the entire SJLIFE cohort was analyzed. ZNF382 was significant in males in the combined cohorts as shown by meta-analyses as well as the depression-associated gene EXO5.

CONCLUSIONS

Further research is needed to confirm whether the current findings, along with other known risk factors, may be valuable in identifying patients at increased risk of these long-term complications.

IMPACT

Our results suggest that specific genes may be related to increased neuropsychological consequences.

Protective effects of Embelin in Benzo[α]pyrene induced cognitive and memory impairment in experimental model of mice

Alzheimer's disease (AD) is a neurodegenerative disease that affects the neurons in the hippocampus, resulting in cognitive and memory impairment. The most prominent clinical characteristics of AD are the production of amyloid-beta (Aβ) plaques, neurofibrillary tangles, and neuroinflammation in neurons. It has been proven that embelin (Emb) possesses antioxidant, anti-inflammatory, and neuroprotective properties. Therefore, we assessed the therapeutic potential of Emb in Benzo [α]pyrene (BaP)-induced cognitive impairment in experimental mice. BaP (5 mg/kg, i. p) was given to mice daily for 28 days, and Emb (2.5, 5, and 10 mg/kg, i. p) was given from 14 to 28 days of a protocol. In addition, locomotor activity was evaluated using open-field and spatial working, and non-spatial memory was evaluated using novel object recognition tasks (NORT), Morris water maze (MWM), and Y- maze. At the end of the study, the animal tissue homogenate was used to check biochemicals, neuroinflammation, and neurotransmitter changes. BaP-treated mice showed a significant decline in locomotor activity, learning and memory deficits and augmented oxidative stress (lipid peroxidation, nitrite, and GSH). Further, BaP promoted the release of inflammatory tissue markers, decreased acetylcholine, dopamine, GABA, serotonin, and norepinephrine, and increased glutamate concentration. However, treatment with Emb at dose-dependently prevented biochemical changes, improved antioxidant levels, reduced neuroinflammation, restored neurotransmitter concentration, and inhibited the NF-κB pathway. The current study's finding suggested that Emb improved cognitive functions through antioxidant, anti-inflammatory, and neuroprotective mechanisms and inhibition of acetylcholinesterase (AChE) enzyme activities and Aβ-42 accumulation.

Aging-Related Protein Alterations in the Brain

Aging is an intrinsic aspect of an organism's life cycle and is characterized by progressive physiological decline and increased susceptibility to mortality. Many age-associated disorders, including neurological disorders, are most commonly linked with the aging process, such as Alzheimer's disease (AD). This review aims to provide a comprehensive overview of the effects of aging and AD on the molecular pathways and levels of different proteins in the brain, including metalloproteins, neurotrophic factors, amyloid proteins, and tau proteins. AD is caused by the aggregation of amyloid proteins in the brain. Factors such as metal ions, protein ligands, and the oligomerization state of amyloid precursor protein significantly influence the proteolytic processing of amyloid-β protein precursor (AβPP). Tau, a disordered cytosolic protein, serves as the principal microtubule-associated protein in mature neurons. AD patients exhibit decreased levels of nerve growth factor within their nervous systems and cerebrospinal fluid. Furthermore, a significant increase in brain-derived neurotrophic factor resulting from the neuroprotective effect of glial cell line-derived neurotrophic factor suggests that the synergistic action of these proteins plays a role in inhibiting neuronal degeneration and atrophy. The mechanism through which Aβ and AβPP govern Cu2+ transport and their influence on Cu2+ and other metal ion pools requires elucidation in future studies. A comprehensive understanding of the influence of aging and AD on molecular pathways and varying protein levels may hold the potential for the development of novel diagnostic and therapeutic methods for the treatment of AD.

The Protective Effects of Pistacia Atlantica Gum in a Rat Model of Aluminum Chloride-Induced Alzheimer's Disease via Affecting BDNF and NF-kB

Alzheimer's disease (AD) is a neurodegenerative condition characterized by progressive cognitive deterioration, including deficits in memory and other cognitive functions. Oxidative stress and free radical damage play significant roles in its pathogenesis. This study aimed to investigate the potential anti-inflammatory and neuroprotective effects of Pistacia atlantica gum (administered at doses of 50 and 100 mg/kg for 14 days) in a rat model of AD induced by aluminum chloride (AlCl3). Behavioral changes were assessed using open field, passive avoidance, and elevated plus maze tests. Additionally, nitrite levels, nuclear factor-kappa B (NF-κB), brain-derived neurotrophic factor (BDNF), and immunostaining were evaluated. Administration of P. atlantica gum significantly increased step-through latency in the passive avoidance test (P < 0.01 and P < 0.001), enhanced mobility in the open field test (P < 0.01 and P < 0.001), and reduced anxiety-like behaviors in the elevated plus maze (P < 0.001) compared to the AlCl3 group. Treatment with the gum partially normalized the elevated levels of NF-κB and the decreased levels of BDNF caused by AlCl3 exposure. Our findings suggest that P. atlantica gum administration may alleviate oxidative stress, neuroinflammation, and cognitive impairment in AD rats.

Betula pendula Leaf Extract Targets the Interplay between Brain Oxidative Stress, Inflammation, and NFkB Pathways in Amyloid Aβ1-42-Treated Rats

Alzheimer's disease (AD) is known as the primary and most common cause of dementia in the middle-aged and elderly population worldwide. Chemical analyses of B. pendula leaf extract (BPE), performed using spectrophotometric and chromatographic methods (LC/MS), revealed high amounts of polyphenol carboxylic acids (gallic, chlorogenic, caffeic, trans-p-coumaric, ferulic, and salicylic acids), as well as flavonoids (apigenin, luteolin, luteolin-7-O-glucoside, naringenin, hyperoside, quercetin, and quercitrin). Four groups of Wistar rats were used in this experiment (n = 7/group): control (untreated), Aβ1-42 (2 μg/rat intracerebroventricular (i.c.v.), Aβ1-42 + BPE (200 mg/Kg b.w.), and DMSO (10 μL/rat). On the first day, one dose of Aβ1-42 was intracerebroventricularly administered to animals in groups 2 and 3. Subsequently, BPE was orally administered for the next 15 days to group 3. On the 16th day, behavioral tests were performed. Biomarkers of brain oxidative stress Malondialdehyde (MDA), (Peroxidase (PRx), Catalase (CAT), and Superoxid dismutase (SOD) and inflammation (cytokines: tumor necrosis factor -α (TNF-α), Interleukin 1β (IL-1β), and cyclooxygenase-2 (COX 2)) in plasma and hippocampus homogenates were assessed. Various protein expressions (Phospho-Tau (Ser404) (pTau Ser 404), Phospho-Tau (Ser396) (pTau Ser 396), synaptophysin, and the Nuclear factor kappa B (NFkB) signaling pathway) were analyzed using Western blot and immunohistochemistry in the hippocampus. The results show that BPE diminished lipid peroxidation and neuroinflammation, modulated specific protein expression, enhanced the antioxidant capacity, and improved spontaneous alternation behavior, suggesting that it has beneficial effects in AD.

Involvement of the aryl hydrocarbon receptor (AhR) in the mechanism of action of elastin-derived peptide (VGVAPG) and its impact on neurosteroidogenesis

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor from the family of basic helix-loop-helix transcription factors. Several studies have indicated an important role of AhR signaling pathways in senescence, aging, and neurodegenerative diseases. During aging, elastin is degraded and elastin-derived peptides (EDPs) are formed. EDPs have been detected in human blood, serum, and cerebrospinal fluid. Literature data suggest a role of EDPs in the development of neurodegenerative diseases. However, the impact of EDPs on the AhR signaling pathway has never been investigated. Therefore, the aim of our paper was to study the role of AhR in the mechanism of action of the VGVAPG peptide (one of the EDPs) in mouse primary astrocytes in vitro. Our experiments have shown that AhR plays an important role in the EDP mechanism of action in a model of mouse primary astrocytes. Moreover, due to the involvement of Sirt3, Pparγ, AhR, Glb1, Nf-κb1, Ece1, Ide, and Nepr genes and the production and release of neurosteroids, VGVAPG can accelerate the development of neurodegenerative diseases in which the proper metabolism of astrocytes is crucial. Furthermore, our studies have proved that AhR is likely involved in the co-control of the Sirt1, Glb1, Nf-κb1, Ece1, and Nepr expression in astrocytes.

Role of multi-targeted bioactive natural molecules and their derivatives in the treatment of Alzheimer's disease: an insight into structure-activity relationship

Alzheimer's disease (AD) is a complex neurodegenerative disorder involving cognitive dysfunction like short-term memory and behavioral changes as the disease progresses due to other unaltered physiological factors. The solution for this problem is Multi-targeted Drugs (MTDs), which can affect multiple determinants to realize the multifunctional effects. Acetylcholinesterase (AChE) inhibitors donepezil, rivastigmine, galantamine, and N-methyl-D-aspartate (NMDA) receptor antagonist memantine are FDA-approved drugs used to treat AD symptomatically. The key objective of this review is to understand multitargeted bioactive natural molecules that could be considered as leads for further development as effective drugs for treating AD, along with understanding its pharmacology and structure-activity relationship (SAR). Understanding the molecular mechanism of the AD pathophysiology, the role of existing drugs, treatment of AD via amyloid beta (Aβ) plaque, and neurofibrillary tangle (NFT) inhibition by natural bioactive molecules were also discussed in the review. The current quest and recent advancements with natural bioactive compounds like physostigmine, resveratrol, curcumin, and catechins, along with the study of in silico SAR, were reported in the present study. This review summarises the structural properties required for bioactive natural molecules to show anti-Alzheimer's activity by emphasizing on SAR of several bioactive natural molecules targeting various AD pathologies, their key molecular interactions that are critical for target specificity, their role as multitargeted ligands, used with adjunctive therapy for AD followed by related US patents granted recently. This article highlights the significance of the structural features of natural bioactive molecules in the treatment of AD and establishes a connection between them.Communicated by Ramaswamy H. Sarma.

Simple model systems reveal conserved mechanisms of Alzheimer's disease and related tauopathies

The lack of effective therapies that slow the progression of Alzheimer's disease (AD) and related tauopathies highlights the need for a more comprehensive understanding of the fundamental cellular mechanisms underlying these diseases. Model organisms, including yeast, worms, and flies, provide simple systems with which to investigate the mechanisms of disease. The evolutionary conservation of cellular pathways regulating proteostasis and stress response in these organisms facilitates the study of genetic factors that contribute to, or protect against, neurodegeneration. Here, we review genetic modifiers of neurodegeneration and related cellular pathways identified in the budding yeast Saccharomyces cerevisiae, the nematode Caenorhabditis elegans, and the fruit fly Drosophila melanogaster, focusing on models of AD and related tauopathies. We further address the potential of simple model systems to better understand the fundamental mechanisms that lead to AD and other neurodegenerative disorders.

From reactive species to disease development: Effect of oxidants and antioxidants on the cellular biomarkers

The influence of modern lifestyle, diet, exposure to chemicals such as phytosanitary substances, together with sedentary lifestyles and lack of exercise play an important role in inducing reactive stress (RS) and disease. The imbalance in the production and scavenging of free radicals and the induction of RS (oxidative, nitrosative, and halogenative) plays an essential role in the etiology of various chronic pathologies, such as cardiovascular diseases, diabetes, neurodegenerative diseases, and cancer. The implication of free radicals and reactive species injury in metabolic disturbances and the onset of many diseases have been accumulating for several decades, and are now accepted as a major cause of many chronic diseases. Exposure to elevated levels of free radicals can cause molecular structural impact on proteins, lipids, and DNA, as well as functional alteration of enzyme homeostasis, leading to aberrations in gene expression. Endogenous depletion of antioxidant enzymes can be mitigated using exogenous antioxidants. The current interest in the use of exogenous antioxidants as adjunctive agents for the treatment of human diseases allows a better understanding of these diseases, facilitating the development of new therapeutic agents with antioxidant activity to improve the treatment of various diseases. Here we examine the role that RS play in the initiation of disease and in the reactivity of free radicals and RS in organic and inorganic cellular components.

A network pharmacology approach to explore pharmacological mechanisms of Asparagus racemosus for ameliorative effect in epilepsy and comorbid progressive memory dysfunction

Background

Network pharmacology approach has been observed a powerful tool to predict underlying complex pharmacological mechanism of herbs. Asparagus racemosus has been reported to show ameliorative effects in treating epilepsy and comorbid memory dysfunction but mechanism of this amelioration is elusive. Hence a network pharmacology approach was employed to investigate the plausible mechanism of A. recemosus.

Methodology

: Bioactive compounds of A. racemosus were extracted based on the TCMSP, PCIDB, and BATMAN-TCM database. The potential targets of bioactive compounds were collected using target fishing. Epilepsy and comorbid dementia genes were collected from DISGENET. A PPI network among these targets was constructed using the intersecting key targets between herb targets and disease targets. Besides, DAVID bioinformatics resource was utilized for the pathway enrichment analysis on GO and KEGG. Ultimately, phytochemical compound-target genes-Pathways network has been assembled utilizing Cytoscape to decipher the mechanism of the herb.

Results

The network analysis revealed that 5 targets (CASP3, TNF, VEGFA, PTGS2 and CNR1) might be the key therapeutic targets of asparagus on Epilepsy comorbid Alzheimer's disease. Based on high connectivity, four hub compounds with the highest connectivity were noted and it includes Shatavarin V, Sarsasapogenin, Shatavarin IX, and Shatavarin VI. A total of 19 KEGG terms were enriched as the potential pathways of A. racemosus in Epilepsy comorbid Alzheimer's disease.

Conclusion

This study envisaged the pharmacological and molecular mechanism of A. racemosus against epilepsy comorbid Alzheimer's disease and put forward a strategy to uncover the mechanisms of Traditional Indian Medicine based on network pharmacology.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-023-00169-x.

The role of melatonin in amyloid beta-induced inflammation mediated by inflammasome signaling in neuronal cell lines

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder. In addition to amyloid beta (Aβ) and tau, neuroinflammation is a crucial element in the etiology of this disease. However, the relevance of inflammasome-induced pyroptosis to AD is unknown. We aimed to clarify whether the anti-inflammatory effects of melatonin could prevent Aβ-mediated activation of the inflammasome. We demonstrated that Aβ upregulated NOD-like receptor family pyrin domain-containing 3 (NLRP3), apoptosis-associated speck-like protein containing a CARD, and cysteinyl aspartate-specific proteinase caspase (caspase 1) expression in SH-SY5Y neuroblastoma cells, resulting in the release of proinflammatory cytokines, including interleukin-1β (IL-1β), interleukin-18 (IL-18) and tumor necrosis factor (TNF-α). Melatonin prevented inflammasome signaling and excessive cytokine release caused by Aβ. We found that ethyl 2[(2-chlorophenyl)(hydroxy) methyl]acrylate (INF-4E, NLRP3 and caspase 1 inhibitor) significantly abolished Aβ-induced proinflammatory cytokine expression. The increase in cleaved-caspase 1, pro-IL18, and cleaved-IL18 caused by Aβ suggested the occurrence of pyroptosis, which was further confirmed by the increased expression of N-terminal gasdermin D (N-GSDMD). Melatonin plays a protective role against Aβ-induced inflammation via an inflammasome-associated mechanism that is essential in inducing the active forms of cytokines and pyroptosis. The ability of melatonin to inhibit inflammasome may represent a turning point in the treatment of AD progression.

The Potential Neuroprotective Effect of Thymoquinone on Scopolamine-Induced In Vivo Alzheimer's Disease-like Condition: Mechanistic Insights

BACKGROUND

Alzheimer's disease (AD) is a common neurodegenerative disorder without effective treatment. Thymoquinone (TQ) has demonstrated potential in exhibiting anti-inflammatory, anti-cancer, and antioxidant characteristics. Despite TQ's neuroprotection effect, there is a scarcity of information regarding its application in AD research, and its molecular trajectories remain ambiguous. Thus, the objective of the current investigation was to examine the potential beneficial effects and underlying mechanisms of TQ in scopolamine (SCOP)-induced neuronal injury to mimic AD in vivo model.

METHODS

Thirty mice were divided into normal, SCOP, and TQ groups. The Y-maze and pole climbing tests were performed to measure memory and motor performance. Afterwards, histopathological and immunohistochemical examinations were carried out. Furthermore, peroxisome proliferator-activated receptor gamma (PPAR-γ) signaling pathway-related proteins and genes were detected with an emphasis on the role of miR-9.

RESULTS

TQ has the potential to ameliorate cognitive deficits observed in SCOP-induced AD-like model, as evidenced by the improvement in behavioral outcomes, histopathological changes, modulation of the expression pattern of PPAR-γ downstream targets with a significant decrease in the deposition of amyloid beta (Aβ).

CONCLUSIONS

TQ provided meaningful multilevel neuroprotection through its anti-inflammatory and its PPAR-γ agonist activity. Consequently, TQ may possess a potential beneficial role against AD development.

The neurobiology and therapeutic potential of multi-targeting β-secretase, glycogen synthase kinase 3β and acetylcholinesterase in Alzheimer's disease

Alzheimer's Disease (AD) is the most common form of dementia, affecting almost 50 million of people around the world, characterized by a complex and age-related progressive pathology with projections to duplicate its incidence by the end of 2050. AD pathology has two major hallmarks, the amyloid beta (Aβ) peptides accumulation and tau hyperphosphorylation, alongside with several sub pathologies including neuroinflammation, oxidative stress, loss of neurogenesis and synaptic dysfunction. In recent years, extensive research pointed out several therapeutic targets which have shown promising effects on modifying the course of the disease in preclinical models of AD but with substantial failure when transposed to clinic trials, suggesting that modulating just an isolated feature of the pathology might not be sufficient to improve brain function and enhance cognition. In line with this, there is a growing consensus that an ideal disease modifying drug should address more than one feature of the pathology. Considering these evidence, β-secretase (BACE1), Glycogen synthase kinase 3β (GSK-3β) and acetylcholinesterase (AChE) has emerged as interesting therapeutic targets. BACE1 is the rate-limiting step in the Aβ production, GSK-3β is considered the main kinase responsible for Tau hyperphosphorylation, and AChE play an important role in modulating memory formation and learning. However, the effects underlying the modulation of these enzymes are not limited by its primarily functions, showing interesting effects in a wide range of impaired events secondary to AD pathology. In this sense, this review will summarize the involvement of BACE1, GSK-3β and AChE on synaptic function, neuroplasticity, neuroinflammation and oxidative stress. Additionally, we will present and discuss new perspectives on the modulation of these pathways on AD pathology and future directions on the development of drugs that concomitantly target these enzymes.

Curcumae radix Reduces Endoplasmic Reticulum Stress in Mice with Chronic Neuroinflammation

Endoplasmic reticulum (ER) stress is a condition in which the ER protein-folding machinery is impaired, leading to the accumulation of improperly folded proteins and triggering an unfolded-protein response. Excessive ER stress causes cell death and contributes to the development of chronic diseases. Interestingly, there is a bidirectional relationship between ER stress and the nuclear factor-kappa B (NF-κB) pathway. Curcumin, a natural polyphenolic compound found in Curcumae radix, exerts its neuroprotective effects by regulating ER stress and inflammation. Therefore, investigating the potential protective and regulatory effects of curcumin on ER stress, inflammation, and neurodegeneration under chronic neuroinflammatory conditions is of great interest. Mice were pretreated with Curcumae radix extract (CRE) for 19 days and then treated with CRE plus lipopolysaccharide for 1 week. We monitored pro-inflammatory cytokine levels in the serum and ER stress-, inflammation-, and neurodegeneration-related markers in the mouse cerebrum and hippocampus using Western blotting and qRT-PCR. CRE reduced Interleukin-1 beta levels in the blood and brain of mice with lipopolysaccharide-induced chronic inflammation. CRE also suppressed the expression of markers related to the ER stress and NF-κB signaling pathways. The expression of neurodegeneration-related markers was reduced in the mouse cerebrum and hippocampus. CRE exerts neuroprotective effects under chronic inflammatory conditions via multifaceted anti-inflammatory and ER stress-pathway regulatory mechanisms.

The Effect of Combined Treatment of Psilocybin and Eugenol on Lipopolysaccharide-Induced Brain Inflammation in Mice

Inflammation is an organism’s biological defense mechanism. Acute and chronic inflammation of the body triggers the production of pro- and anti-inflammatory pathways that can affect the content of cytokines in the brain and thus cause brain inflammation. Disorders such as depression and posttraumatic stress disorder (PTSD) are often associated with elevated inflammation. Recently, positive and promising clinical results of psilocybin for the treatment of depression and PTSD were reported. Thus, we decided to test whether psilocybin alone or in combination with eugenol, an anti-inflammatory and antioxidant agent, would prevent the increase in or decrease the content of cytokines in the brain of C57BL/6J mice injected with lipopolysaccharides (LPS). Two experiments were performed, one with pre-treatment of mice through gavage with psilocybin (0.88 mg/kg), eugenol (17.6 mg/kg), or combinations of psilocybin and eugenol (1:10, 1:20, or 1:50), followed by intraperitoneal injection of LPS, and the second, post-treatment, with initial injection with LPS, followed by treatment with psilocybin, eugenol, or their combination. Brain tissues were collected, and cytokines were analyzed by qRT-PCR, Western blot, and ELISA. Data were analyzed with a one-way ANOVA followed by Tukey’s post hoc test or with multiple unpaired t-tests. LPS upregulated mRNA expression of COX-2, TNF-α, IL-1β, and IL-6. All pre-treatments decreased the expression of COX-2 and TNF-α, with psilocybin alone and in 1:50 combination, with eugenol being the most effective. In the post-treatment, all combinations of psilocybin and eugenol were effective in reducing inflammation, with the 1:50 ratio displaying the most prominent results in reducing the mRNA content of tested cytokines. Western blot analysis confirmed the effect on COX-2 and IL-1β proteins. Finally, the ELISA showed that post-treatment with psilocybin + eugenol (1:50) demonstrated the best results, decreasing the expression of multiple markers including IL-6 and IL-8. This demonstrates the anti-inflammatory effects of a combination of psilocybin and eugenol in the brain of animals with systemically induced inflammation.

Early activation of Toll-like receptor-3 reduces the pathological progression of Alzheimer's disease in APP/PS1 mouse

BACKGROUND

Toll-like receptor 3 (TLR3) plays an important role in the immune/inflammatory response in the nervous system and is a main pathological feature of Alzheimer's disease (AD). This study investigates the role of early activation of TLR3 in the pathophysiological process of AD.

METHODS

In the experiment, the agonist of TLR3, Poly(I:C), was intraperitoneally injected into the APP/PS1 mouse model of AD and wild-type control mice starting from the age of 4 to 9 months. At the age of 14 months, behavioral tests were conducted. Western blot and immunohistochemistry staining were used to evaluate the level of amyloid β-protein (Aβ), the activation of inflammatory cells, and neuron loss. In addition, the levels of inflammatory cytokines were measured using a quantitative polymerase chain reaction.

RESULTS

The results demonstrated that the early activation of TLR3 attenuated neuronal loss and neurobehavioral dysfunction. Moreover, the early activation of TLR3 reduced Aβ deposition, inhibited the activation of microglia and astrocytes, and decreased the transcription of pro-inflammatory factors in the hippocampus.

CONCLUSIONS

The results indicated that the activation of TLR3 by Poly (I:C) in the early stage of development of AD in a mouse model attenuated neuron loss and improved neurobehavioral functions. The underlying mechanisms could be attributed to its role in Aβ clearance, the inhibition of glial cells, and the regulation of neuroinflammation in the hippocampus.

Anti-Inflammatory and Antioxidative Phytogenic Substances against Secret Killers in Poultry: Current Status and Prospects

Chronic stress is recognized as a secret killer in poultry. It is associated with systemic inflammation due to cytokine release, dysbiosis, and the so-called leaky gut syndrome, which mainly results from oxidative stress reactions that damage the barrier function of the cells lining the gut wall. Poultry, especially the genetically selected broiler breeds, frequently suffer from these chronic stress symptoms when exposed to multiple stressors in their growing environments. Since oxidative stress reactions and inflammatory damages are multi-stage and long-term processes, overshooting immune reactions and their down-stream effects also negatively affect the animal's microbiota, and finally impair its performance and commercial value. Means to counteract oxidative stress in poultry and other animals are, therefore, highly welcome. Many phytogenic substances, including flavonoids and phenolic compounds, are known to exert anti-inflammatory and antioxidant effects. In this review, firstly, the main stressors in poultry, such as heat stress, mycotoxins, dysbiosis and diets that contain oxidized lipids that trigger oxidative stress and inflammation, are discussed, along with the key transcription factors involved in the related signal transduction pathways. Secondly, the most promising phytogenic substances and their current applications to ameliorate oxidative stress and inflammation in poultry are highlighted.

miRNAs and Stem Cells as Promising Diagnostic and Therapeutic Targets for Alzheimer's Disease

Alzheimer's disease (AD) is a cumulative progressive neurodegenerative disease characterized mainly by impairment in cognitive functions accompanied by memory loss, disturbance in behavior and personality, and difficulties in learning. Although the main causes of AD pathogenesis are not fully understood yet, amyloid-β peptides and tau proteins are supposed to be responsible for AD onset and pathogenesis. Various demographic, genetic, and environmental risk factors are involved in AD onset and pathogenesis such as age, gender, several genes, lipids, malnutrition, and poor diet. Significant changes were observed in microRNA (miRNA) levels between normal and AD cases giving hope for a diagnostic procedure for AD through a simple blood test. As yet, only two classes of AD therapeutic drugs are approved by FDA. They are classified as acetylcholinesterase inhibitors and N-methyl-D-aspartate antagonists (NMDA). Unfortunately, they can only treat the symptoms but cannot cure AD or stop its progression. New therapeutic approaches were developed for AD treatment including acitretin due to its ability to cross blood-brain barrier in the brain of rats and mice and induce the expression of ADAM 10 gene, the α-secretase of human amyloid-β protein precursor, stimulating the non-amyloidogenic pathway for amyloid-β protein precursor processing resulting in amyloid-β reduction. Also stem cells may have a crucial role in AD treatment as they can improve cognitive functions and memory in AD rats through regeneration of damaged neurons. This review spotlights on promising diagnostic techniques such as miRNAs and therapeutic approaches such as acitretin and/or stem cells keeping in consideration AD pathogenesis, stages, symptoms, and risk factors.

The effects of microglia-associated neuroinflammation on Alzheimer's disease

Alzheimer's disease (AD) is defined as a severe chronic degenerative neurological disease in human. The pathogenic mechanism of AD has been convincingly elucidated by the "amyloid cascade hypothesis" with the main focus of the pathological accretion of β-amyloid (Aβ) peptides outside the cell. However, increasing evidence suggests that this hypothesis is weak in explaining the pathogenesis of AD. Neuroinflammation is crucial in the development of AD, which is proven by the elevated levels of inflammatory markers and the identification of AD risk genes relevant to the innate immune function. Here, we summarize the effects of microglia-mediated neuroinflammation on AD, focusing on the temporal and spatial changes in microglial phenotype, the interactions among microglia, Aβ, tau, and neurons, and the prospects and recent advances in neuroinflammation as a diagnostic and therapeutic target of AD.

Targeting the overexpressed mitochondrial protein VDAC1 in a mouse model of Alzheimer's disease protects against mitochondrial dysfunction and mitigates brain pathology

BACKGROUND

Alzheimer's disease (AD) exhibits mitochondrial dysfunctions associated with dysregulated metabolism, brain inflammation, synaptic loss, and neuronal cell death. As a key protein serving as the mitochondrial gatekeeper, the voltage-dependent anion channel-1 (VDAC1) that controls metabolism and Ca²⁺ homeostasis is positioned at a convergence point for various cell survival and death signals. Here, we targeted VDAC1 with VBIT-4, a newly developed inhibitor of VDAC1 that prevents its pro-apoptotic activity, and mitochondria dysfunction.

METHODS

To address the multiple pathways involved in AD, neuronal cultures and a 5 × FAD mouse model of AD were treated with VBIT-4. We addressed multiple topics related to the disease and its molecular mechanisms using immunoblotting, immunofluorescence, q-RT-PCR, 3-D structural analysis and several behavioral tests.

RESULTS

In neuronal cultures, amyloid-beta (Aβ)-induced VDAC1 and p53 overexpression and apoptotic cell death were prevented by VBIT-4. Using an AD-like 5 × FAD mouse model, we showed that VDAC1 was overexpressed in neurons surrounding Aβ plaques, but not in astrocytes and microglia, and this was associated with neuronal cell death. VBIT-4 prevented the associated pathophysiological changes including neuronal cell death, neuroinflammation, and neuro-metabolic dysfunctions. VBIT-4 also switched astrocytes and microglia from being pro-inflammatory/neurotoxic to neuroprotective phenotype. Moreover, VBIT-4 prevented cognitive decline in the 5 × FAD mice as evaluated using several behavioral assessments of cognitive function. Interestingly, VBIT-4 protected against AD pathology, with no significant change in phosphorylated Tau and only a slight decrease in Aβ-plaque load.

CONCLUSIONS

The study suggests that mitochondrial dysfunction with its gatekeeper VDAC1 is a promising target for AD therapeutic intervention, and VBIT-4 is a promising drug candidate for AD treatment.

Inflammation context in Alzheimer's disease, a relationship intricate to define

Alzheimer's disease (AD), the most common form of dementia, is characterized by the accumulation of amyloid β (Aβ) and hyperphosphorylated tau protein aggregates. Importantly, Aβ and tau species are able to activate astrocytes and microglia, which release several proinflammatory cytokines, such as tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β), together with reactive oxygen (ROS) and nitrogen species (RNS), triggering neuroinflammation. However, this inflammatory response has a dual function: it can play a protective role by increasing Aβ degradation and clearance, but it can also contribute to Aβ and tau overproduction and induce neurodegeneration and synaptic loss. Due to the significant role of inflammation in the pathogenesis of AD, several inflammatory mediators have been proposed as AD markers, such as TNF-α, IL-1β, Iba-1, GFAP, NF-κB, TLR2, and MHCII. Importantly, the use of anti-inflammatory drugs such as NSAIDs has emerged as a potential treatment against AD. Moreover, diseases related to systemic or local inflammation, including infections, cerebrovascular accidents, and obesity, have been proposed as risk factors for the development of AD. In the following review, we focus on key inflammatory processes associated with AD pathogenesis.

Mechanistic insight into female predominance in Alzheimer's disease based on aberrant protein S-nitrosylation of C3

Protein S-nitros(yl)ation (SNO) is a posttranslational modification involved in diverse processes in health and disease and can contribute to synaptic damage in Alzheimer's disease (AD). To identify SNO proteins in AD brains, we used triaryl phosphine (SNOTRAP) combined with mass spectrometry (MS). We detected 1449 SNO proteins with 2809 SNO sites, representing a wide range of S-nitrosylated proteins in 40 postmortem AD and non-AD human brains from patients of both sexes. Integrative protein ranking revealed the top 10 increased SNO proteins, including complement component 3 (C3), p62 (SQSTM1), and phospholipase D3. Increased levels of S-nitrosylated C3 were present in female over male AD brains. Mechanistically, we show that formation of SNO-C3 is dependent on falling β-estradiol levels, leading to increased synaptic phagocytosis and thus synapse loss and consequent cognitive decline. Collectively, we demonstrate robust alterations in the S-nitrosoproteome that contribute to AD pathogenesis in a sex-dependent manner.

Combination of Donepezil and Memantine Attenuated Cognitive Impairment Induced by Mixed Endocrine-Disrupting Chemicals: an In Silico Study

Little is known about the effects of endocrine-disrupting chemicals (EDCs) and the combination of memantine and donepezil on the pathogenesis of cognitive impairment. Here, we aimed to identify in silico the molecular mechanisms of the combination of memantine and donepezil that combat cognitive impairment induced by nine common EDCs using GeneMania, AutoDock Vina, Metascape, SwissADME, MIENTURNET, and miRNAsong. We observed that the mixture of memantine and donepezil had therapeutic effects on mixed EDC-induced cognitive impairment via five genes (TNF, ACHE, BAX, IL1B, and CASP3). With ACHE and TNF, donepezil and memantine both had a high docking score, respectively. The predominant connections among five mutual genes were physical interactions (77.6%). The major pathways associated with memantine and donepezil countering cognitive impairment generated by mixed EDCs were discovered to be "AGE-RAGE signaling pathway in diabetic complications," "pro-survival signaling of neuroprotectin D1," and "non-alcoholic fatty liver disease." The miRNAs and transcription factors implicated in memantine and donepezil protecting against mixed EDCs were hsa-miR-128-3p and hsa-miR-34a-5p, NFKB1, NFKB2, IRF8, and E2F4. The sponges' tertiary structure predictions for two major miRNAs were provided. The physicochemical and pharmacokinetic properties of memantine and donepezil highlighted the need for a therapeutic combination of these medications to treat cognitive impairment.

Intranasal Peptide Therapeutics: A Promising Avenue for Overcoming the Challenges of Traditional CNS Drug Development

The central nervous system (CNS) has, among all organ systems in the human body, the highest failure rate of traditional small-molecule drug development, ranging from 80-100% depending on the area of disease research. This has led to widespread abandonment by the pharmaceutical industry of research and development for CNS disorders, despite increased diagnoses of neurodegenerative disorders and the continued lack of adequate treatment options for brain injuries, stroke, neurodevelopmental disorders, and neuropsychiatric illness. However, new approaches, concurrent with the development of sophisticated bioinformatic and genomic tools, are being used to explore peptide-based therapeutics to manipulate endogenous pathways and targets, including "undruggable" intracellular protein-protein interactions (PPIs). The development of peptide-based therapeutics was previously rejected due to systemic off-target effects and poor bioavailability arising from traditional oral and systemic delivery methods. However, targeted nose-to-brain, or intranasal (IN), approaches have begun to emerge that allow CNS-specific delivery of therapeutics via the trigeminal and olfactory nerve pathways, laying the foundation for improved alternatives to systemic drug delivery. Here we review a dozen promising IN peptide therapeutics in preclinical and clinical development for neurodegenerative (Alzheimer's, Parkinson's), neuropsychiatric (depression, PTSD, schizophrenia), and neurodevelopmental disorders (autism), with insulin, NAP (davunetide), IGF-1, PACAP, NPY, oxytocin, and GLP-1 agonists prominent among them.

Manipulation of the diet-microbiota-brain axis in Alzheimer's disease

Several studies investigating the pathogenesis of Alzheimer's disease have identified various interdependent constituents contributing to the exacerbation of the disease, including Aβ plaque formation, tau protein hyperphosphorylation, neurofibrillary tangle accumulation, glial inflammation, and the eventual loss of proper neural plasticity. Recently, using various models and human patients, another key factor has been established as an influential determinant in brain homeostasis: the gut-brain axis. The implications of a rapidly aging population and the absence of a definitive cure for Alzheimer's disease have prompted a search for non-pharmaceutical tools, of which gut-modulatory therapies targeting the gut-brain axis have shown promise. Yet multiple recent studies examining changes in human gut flora in response to various probiotics and environmental factors are limited and difficult to generalize; whether the state of the gut microbiota in Alzheimer's disease is a cause of the disease, a result of the disease, or both through numerous feedback loops in the gut-brain axis, remains unclear. However, preliminary findings of longitudinal studies conducted over the past decades have highlighted dietary interventions, especially Mediterranean diets, as preventative measures for Alzheimer's disease by reversing neuroinflammation, modifying the intestinal and blood-brain barrier (BBB), and addressing gut dysbiosis. Conversely, the consumption of Western diets intensifies the progression of Alzheimer's disease through genetic alterations, impaired barrier function, and chronic inflammation. This review aims to support the growing body of experimental and clinical data highlighting specific probiotic strains and particular dietary components in preventing Alzheimer's disease via the gut-brain axis.

The role of mixed B vitamin intakes on cognitive performance: Modeling, genes and miRNAs involved

OBJECTIVE

To assess the relationships between mixed B vitamin intakes (B1, B2, B3, B6, B9, B12) and cognitive performance, as well as their molecular mechanisms.

METHODS

The associations of mixed B vitamin intakes with cognitive function were assessed using multivariate regression models, weighted quantile sum (WQS), quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR). GeneMANIA, Comparative Toxicogenomics Database, MIENTURNET, miRNAsong were employed as the main data-mining methods.

RESULTS

Overall effects of the B vitamin intake mixture were significantly associated with global cognition in the WQS, qgcomp, and BKMR models. A mixture of B vitamins (B1, B2, B3, B9) interacted with the five genes (IL1B, BCL2, CASP3, BAX, PTGS2) and was associated with better cognitive function, especially CASP3 and BAX. Physical interactions (77.6%) were observed to be the most important interactions in gene networks. The IL-18 signaling pathway, apoptosis, and Alzheimer's disease were annotated as the key molecular mechanisms involved in mixed B vitamins' improving cognitive function. NFKB1, ATF3, and NR3C1 were the key significant transcription factors associated with cognitive function targeted by a mixture of B vitamins. The strong interaction and expression of hsa-miR-34a-5p, hsa-miR-128-3p, hsa-miR-181a-5p, and hsa-miR-204-5p are involved in mixed B vitamins' better cognitive performance. We also created and evaluated miRNA sponge sequences for these miRNAs, which might be used to alleviate cognitive decline. The cutoff thresholds for B vitamin intake levels that are associated with cognition performance were reported.

CONCLUSIONS

Given the increased incidence of dementia across the world, increasing daily mixed B vitamin intake via regular meals may contribute to minimizing dementia risk. Further studies are warranted to identify these links in well-characterized cohorts of diverse populations, either independently or together.

The TWEAK/Fn14/CD163 axis-implications for metabolic disease

TWEAK (tumor necrosis factor-like weak inducer of apoptosis) is a member of the TNF superfamily that controls a multitude of cellular events including proliferation, migration, differentiation, apoptosis, angiogenesis, and inflammation. TWEAK control of these events is via an expanding list of intracellular signalling pathways which include NF-κB, ERK/MAPK, Notch, EGFR and AP-1. Two receptors have been identified for TWEAK - Fn14, which targets the membrane bound form of TWEAK, and CD163, which scavenges the soluble form of TWEAK. TWEAK appears to elicit specific events based on the receptor to which it binds, tissue type in which it is expressed, specific extrinsic conditions, and the presence of other cytokines. TWEAK signalling is protective in healthy tissues, but in chronic inflammatory states become detrimental to the tissue. Consistent data show a role for the TWEAK/FN14/CD163 axis in metabolic disease, chronic autoimmune diseases, and acute ischaemic stroke. Low circulating concentrations of soluble TWEAK are predictive of poor cardiovascular outcomes in those with and without diabetes. This review details the current understanding of the TWEAK/Fn14/CD163 axis as one of the chief regulators of immune signalling and its cell-specific role in metabolic disease development and progression.

The functional mechanism of bone marrow-derived mesenchymal stem cells in the treatment of animal models with Alzheimer's disease: crosstalk between autophagy and apoptosis

The transplantation of bone marrow-derived mesenchymal stem cells (BMMSCs) alleviates neuropathology and improves cognitive deficits in animal models with Alzheimer's disease. However, the underlying mechanism remains undefined. Based on meta-analysis and comprehensive review, high-profile studies support the theory that transplanted BMMSCs activate autophagy, as evidenced by the expression levels of signal molecules such as Beclin-1, Atg5, LC3-II, and mTOR. Functional autophagy mitigates neuronal apoptosis, which is reflected by the alterations of IAPs, Bcl-2, caspase-3, and so forth. Moreover, the transplantation of BMMSCs can decrease aberrant amyloid-beta peptides as well as tau aggregates, inhibit neuroinflammation, and stimulate synaptogenesis. There is a signal crosstalk between autophagy and apoptosis, which may be regulated to produce synergistic effect on the preconditioning of stem cells. Forasmuch, the therapeutic effect of transplanted BMMSCs can be enhanced by autophagy and/or apoptosis modulators.

Epigallocatechin-3-Gallate (EGCG): New Therapeutic Perspectives for Neuroprotection, Aging, and Neuroinflammation for the Modern Age

Alzheimer’s and Parkinson’s diseases are the two most common forms of neurodegenerative diseases. The exact etiology of these disorders is not well known; however, environmental, molecular, and genetic influences play a major role in the pathogenesis of these diseases. Using Alzheimer’s disease (AD) as the archetype, the pathological findings include the aggregation of Amyloid Beta (Aβ) peptides, mitochondrial dysfunction, synaptic degradation caused by inflammation, elevated reactive oxygen species (ROS), and cerebrovascular dysregulation. This review highlights the neuroinflammatory and neuroprotective role of epigallocatechin-3-gallate (EGCG): the medicinal component of green tea, a known nutraceutical that has shown promise in modulating AD progression due to its antioxidant, anti-inflammatory, and anti-aging abilities. This report also re-examines the current literature and provides innovative approaches for EGCG to be used as a preventive measure to alleviate AD and other neurodegenerative disorders.

IAPP-induced beta cell stress recapitulates the islet transcriptome in type 2 diabetes

AIMS/HYPOTHESIS

Type 2 diabetes is characterised by islet amyloid and toxic oligomers of islet amyloid polypeptide (IAPP). We posed the questions, (1) does IAPP toxicity induce an islet response comparable to that in humans with type 2 diabetes, and if so, (2) what are the key transcriptional drivers of this response?

METHODS

The islet transcriptome was evaluated in five groups of mice: beta cell specific transgenic for (1) human IAPP, (2) rodent IAPP, (3) human calpastatin, (4) human calpastatin and human IAPP, and (5) wild-type mice. RNA sequencing data was analysed by differential expression analysis and gene co-expression network analysis to establish the islet response to adaptation to an increased beta cell workload of soluble rodent IAPP, the islet response to increased expression of oligomeric human IAPP, and the extent to which the latter was rescued by suppression of calpain hyperactivation by calpastatin. Rank-rank hypergeometric overlap analysis was used to compare the transcriptome of islets from human or rodent IAPP transgenic mice vs humans with prediabetes or type 2 diabetes.

RESULTS

The islet transcriptomes in humans with prediabetes and type 2 diabetes are remarkably similar. Beta cell overexpression of soluble rodent or oligomer-prone human IAPP induced changes in islet transcriptome present in prediabetes and type 2 diabetes, including decreased expression of genes that confer beta cell identity. Increased expression of human IAPP, but not rodent IAPP, induced islet inflammation present in prediabetes and type 2 diabetes in humans. Key mediators of the injury responses in islets transgenic for human IAPP or those from individuals with type 2 diabetes include STAT3, NF-κB, ESR1 and CTNNB1 by transcription factor analysis and COL3A1, NID1 and ZNF800 by gene regulatory network analysis.

CONCLUSIONS/INTERPRETATION

Beta cell injury mediated by IAPP is a plausible mechanism to contribute to islet inflammation and dedifferentiation in type 2 diabetes. Inhibition of IAPP toxicity is a potential therapeutic target in type 2 diabetes.

Higher baseline levels of CSF inflammation increase risk of incident mild cognitive impairment and Alzheimer's disease dementia

Introduction

Few studies have investigated how neuroinflammation early in the disease course may affect Alzheimer's disease (AD) progression over time despite evidence that neuroinflammation is associated with AD.

Methods

Research participants with cerebrospinal fluid (CSF) biomarkers from the Alzheimer's Disease Neuroimaging Initiative (ADNI) were included in this study. Cox models were used to investigate whether baseline CSF neuroinflammation was associated with incident mild cognitive impairment (MCI) or AD. Moderating effects of sex and apolipoprotein E (APOE) ε4 were also examined.

Results

Elevated levels of tumor necrosis factor α (TNF‐α), interleukin (IL)‐9, and IL‐12p40 at baseline were associated with higher rates of conversion to MCI/AD. Interactions with sex and APOE ε4 were observed, such that women with elevated TNF‐α and all APOE ε4 carriers with elevated IL‐9 levels had shorter times to conversion. In addition, TNF‐α mediated the relationship between elevated IL‐12p40 and IL‐9.

Discussion

Elevated neuroinflammation markers are associated with incident MCI/AD, and the factors of sex and APOE ε4 status modify the time to conversion.

The Potential of N-Acetyl-L-Cysteine (NAC) in the Treatment of Psychiatric Disorders

N-acetyl-L-cysteine (NAC) is a compound of increasing interest in the treatment of psychiatric disorders. Primarily through its antioxidant, anti-inflammatory, and glutamate modulation activity, NAC has been investigated in the treatment of neurodevelopmental disorders, schizophrenia spectrum disorders, bipolar-related disorders, depressive disorders, anxiety disorders, obsessive compulsive-related disorders, substance-use disorders, neurocognitive disorders, and chronic pain. Whilst there is ample preclinical evidence and theoretical justification for the use of NAC in the treatment of multiple psychiatric disorders, clinical trials in most disorders have yielded mixed results. However, most studies have been underpowered and perhaps too brief, with some evidence of benefit only after months of treatment with NAC. Currently NAC has the most evidence of having a beneficial effect as an adjuvant agent in the negative symptoms of schizophrenia, severe autism, depression, and obsessive compulsive and related disorders. Future research with well-powered studies that are of sufficient length will be critical to better understand the utility of NAC in the treatment of psychiatric disorders.

Beneficial effects of QTC-4-MeOBnE in an LPS-induced mouse model of depression and cognitive impairments: The role of blood-brain barrier permeability, NF-κB signaling, and microglial activation

Clinical and preclinical investigations have suggested a possible biological link betweenmajor depressive disorder (MDD) and Alzheimer's disease (AD). Therefore, a pharmacologic approach to treating MDD could be envisioned as a preventative therapy for some AD cases. In line with this, 1-(7-chloroquinolin-4-yl)-N-(4-methoxybenzyl)-5-methyl-1H-1,2,3-triazole-4 carboxamide (QTC-4-MeOBnE) is characterized as an inhibitor of β-secretase, glycogen synthase kinase 3β, and acetylcholinesterase and has also shown secondary effects underlying the modulation of neurogenesis and synaptic plasticity pathways. Therefore, we investigated the effects of QTC-4-MeOBnE treatment (0.1 or 1 mg/kg) on depressive-like behavior and cognitive impairments elicited by repeated injections of lipopolysaccharide (LPS; 250 μg/kg) in mice. Injections of LPS for seven days led to memory impairments and depressive-like behavior, as evidenced in the Y-maze/object recognition test and forced swimming/splash tests, respectively. However, these impairments were prevented in mice that, after the last LPS injection, were also treated with QTC-4-MeOBnE (1 mg/kg). This effect was associated with restoring blood-brain barrier permeability, reducing oxidative/nitrosative biomarkers, and decreasing neuroinflammation mediated NF-κB signaling in the hippocampus and cortex of the mice. To further investigate the involvement with NF-κB signaling, we evaluated the effects of QTC-4-MeOBnE on microglial cell activation through canonical and non-canonical pathways and the modulation of the involved components. Together, our findings highlight the pharmacological benefits of QTC-4-MeOBnE in a mouse model of sickness behavior and memory impairments, supporting the novel concept that since this molecule produces anti-depressant activity, it could also be beneficial for preventing AD onset and related dementias in subjects suffering from MDD through inflammatory pathway modulation.

Common genetic signatures of Alzheimer's disease in Down Syndrome

Background: People with Down Syndrome (DS) are born with an extra copy of Chromosome (Chr) 21 and many of these individuals develop Alzheimer’s Disease (AD) when they age. This is due at least in part to the extra copy of the APP gene located on Chr 21. By 40 years, most people with DS have amyloid plaques which disrupt brain cell function and increase their risk for AD. About half of the people with DS develop AD and the associated dementia around 50 to 60 years of age, which is about the age at which the hereditary form of AD, early onset AD, manifests. In the absence of Chr 21 trisomy, duplication of APP alone is a cause of early onset Alzheimer’s disease, making it likely that having three copies of APP is important in the development of AD and in DS.

Methods: We investigate the relationship between AD and DS through integrative analysis of genesets derived from a MeSH query of AD and DS associated beta amyloid peptides, Chr 21, GWAS identified AD risk factor genes, and differentially expressed genes in individuals with DS.

Results:  Unique and shared aspects of each geneset were evaluated based on  functional enrichment analysis, transcription factor profile and network interactions. Genes that may be important to both disorders in the context of direct association with APP processing, Tau post translational modification  and network connectivity are ACSM1, APBA2, APLP1, BACE2, BCL2L, COL18A1, DYRK1A, IK, KLK6, METTL2B, MTOR, NFE2L2, NFKB1, PRSS1, QTRT1, RCAN1, RUNX1, SAP18 SOD1, SYNJ1, S100B.

Conclusions: Our findings confirm that oxidative stress, apoptosis, inflammation and immune system processes likely contribute to the pathogenesis of AD and DS which is consistent with other published reports.

Topological Dissection of Proteomic Changes Linked to the Limbic Stage of Alzheimer's Disease

Alzheimer’s disease (AD) is a neurodegenerative disorder and the most common cause of dementia worldwide. In AD, neurodegeneration spreads throughout different areas of the central nervous system (CNS) in a gradual and predictable pattern, causing progressive memory decline and cognitive impairment. Deposition of neurofibrillary tangles (NFTs) in specific CNS regions correlates with the severity of AD and constitutes the basis for disease classification into different Braak stages (I-VI). Early clinical symptoms are typically associated with stages III-IV (i.e., limbic stages) when the involvement of the hippocampus begins. Histopathological changes in AD have been linked to brain proteome alterations, including aberrant posttranslational modifications (PTMs) such as the hyperphosphorylation of Tau. Most proteomic studies to date have focused on AD progression across different stages of the disease, by targeting one specific brain area at a time. However, in AD vulnerable regions, stage-specific proteomic alterations, including changes in PTM status occur in parallel and remain poorly characterized. Here, we conducted proteomic, phosphoproteomic, and acetylomic analyses of human postmortem tissue samples from AD (Braak stage III-IV, n=11) and control brains (n=12), covering all anatomical areas affected during the limbic stage of the disease (total hippocampus, CA1, entorhinal and perirhinal cortices). Overall, ~6000 proteins, ~9000 unique phosphopeptides and 221 acetylated peptides were accurately quantified across all tissues. Our results reveal significant proteome changes in AD brains compared to controls. Among others, we have observed the dysregulation of pathways related to the adaptive and innate immune responses, including several altered antimicrobial peptides (AMPs). Notably, some of these changes were restricted to specific anatomical areas, while others altered according to disease progression across the regions studied. Our data highlights the molecular heterogeneity of AD and the relevance of neuroinflammation as a major player in AD pathology. Data are available via ProteomeXchange with identifier PXD027173.

Aplysia Neurons as a Model of Alzheimer's Disease: Shared Genes and Differential Expression

Although Alzheimer’s disease (AD) is the most common form of dementia in the United States, development of therapeutics has proven difficult. Invertebrate alternatives to current mammalian AD models have been successfully employed to study the etiology of the molecular hallmarks of AD. The marine snail Aplysia californica offers a unique and underutilized system in which to study the physiological, behavioral, and molecular impacts of AD. Mapping of the Aplysia proteome to humans and cross-referencing with two databases of genes of interest in AD research identified 898 potential orthologs of interest in Aplysia. Included among these orthologs were alpha, beta and gamma secretases, amyloid-beta, and tau. Comparison of age-associated differential expression in Aplysia sensory neurons with that of late-onset AD in the frontal lobe identified 59 ortholog with concordant differential expression across data sets. The 21 concordantly upregulated genes suggested increased cellular stress and protein dyshomeostasis. The 47 concordantly downregulated genes included important components of diverse neuronal processes, including energy metabolism, mitochondrial homeostasis, synaptic signaling, Ca⁺⁺ regulation, and cellular cargo transport. Compromised functions in these processes are known hallmarks of both human aging and AD, the ramifications of which are suggested to underpin cognitive declines in aging and neurodegenerative disease.

Neuroinflammatory Signaling in the Pathogenesis of Alzheimer's Disease

Alzheimer’s disease (AD) is a chronic neurodegenerative disease characterized by the formation of intracellular neurofibrillary tangles (NFTs) and extracellular amyloid plaques. Growing evidence has suggested that AD pathogenesis is not only limited to the neuronal compartment but also strongly interacts with immunological processes in the brain. On the other hand, aggregated and misfolded proteins can bind with pattern recognition receptors located on astroglia and microglia and can, in turn, induce an innate immune response, characterized by the release of inflammatory mediators, ultimately playing a role in both the severity and the progression of the disease. It has been reported by genome-wide analysis that several genes which elevate the risk for sporadic AD encode for factors controlling the inflammatory response and glial clearance of misfolded proteins. Obesity and systemic inflammation are examples of external factors which may interfere with the immunological mechanisms of the brain and can induce disease progression. In this review, we discussed the mechanisms and essential role of inflammatory signaling pathways in AD pathogenesis. Indeed, interfering with immune processes and modulation of risk factors may lead to future therapeutic or preventive AD approaches.

Microarray Analysis Revealed Inflammatory Transcriptomic Changes after LSL60101 Treatment in 5XFAD Mice Model

I2-IR have been found dysregulated in patients with neurodegenerative diseases, such as Alzheimer's disease (AD), in which the importance of neuroinflammation in the establishment and maintenance of cognitive decline is well-documented. To research the implication of I2-IR in neuroinflammatory pathways altered in AD, we determined the expression profile of genes associated with inflammation in the 5XFAD model treated with LSL60101, a well-established I2-IR ligand. Thus, we performed a qPCR array containing 84 inflammation-related genes. Hierarchical clustering analysis revealed three gene clusters, suggesting that treatment with LSL60101 affects the gene expression associated with inflammation in the 5XFAD model. Furthermore, we evaluated the functions of the three clusters; thereby performing a pathway enrichment analysis using the GO database. As we expected, clusters 2 and 3 showed alterations in the inflammatory response, chemotaxis and the chemokine-mediated signaling pathway, among others. To validate previous results from the gene profiling analysis, the expression levels of a representative subset of mRNAs were selected according to the intensity of the observed changes and their biological relevance. Interestingly, changes induced by LSL60101 in the 5XFAD model were validated for several genes. These results suggest that treatment with LSL60101 in the 5XFAD model reverses the inflammatory process during the development of AD.

Apoptotic Pathways and Alzheimer's Disease: Probing Therapeutic Potential

Apoptosis is an intrinsic biochemical, cellular process that regulates cell death and is crucial for cell survival, cellular homeostasis, and maintaining the optimum functional status. Apoptosis in a predetermined and programmed manner regulates several molecular events, including cell turnover, embryonic development, and immune system functions but may be the exclusive contributor to several disorders, including neurodegenerative manifestations, when it functions in an aberrant and disorganized manner. Alzheimer's disease (AD) is a fatal, chronic neurodegenerative disorder where apoptosis has a compelling and divergent role. The well-characterized pathological features of AD, including extracellular plaques of amyloid-beta, intracellular hyperphosphorylated tangles of tau protein (NFTs), inflammation, mitochondrial dysfunction, oxidative stress, and excitotoxic cell death, also instigate an abnormal apoptotic cascade in susceptible brain regions (cerebral cortex, hippocampus). The apoptotic players in these regions affect cellular organelles (mitochondria and endoplasmic reticulum), interact with trophic factors, and several pathways, including PI3K/AKT, JNK, MAPK, mTOR signalling. This dysregulated apoptotic cascade end with an abnormal neuronal loss which is a primary event that may precede the other events of AD progression and correlates well with the degree of dementia. The present review provides insight into the diverse and versatile apoptotic mechanisms that are indispensable for neuronal survival and constitute an integral part of the pathological progression of AD. Identification of potential targets (restoring apoptotic and antiapoptotic balance, caspases, TRADD, RIPK1, FADD, TNFα, etc.) may be valuable and advantageous to decide the fate of neurons and to develop potential therapeutics for treatment of AD.

Inflammation and Alzheimer's Disease: Mechanisms and Therapeutic Implications by Natural Products

Alzheimer's disease (AD) is a neurodegenerative disorder with no clear causative event making the disease difficult to diagnose and treat. The pathological hallmarks of AD include amyloid plaques, neurofibrillary tangles, and widespread neuronal loss. Amyloid-beta has been extensively studied and targeted to develop an effective disease-modifying therapy, but the success rate in clinical practice is minimal. Recently, neuroinflammation has been focused on as the event in AD progression to be targeted for therapies. Various mechanistic pathways including cytokines and chemokines, complement system, oxidative stress, and cyclooxygenase pathways are linked to neuroinflammation in the AD brain. Many cells including microglia, astrocytes, and oligodendrocytes work together to protect the brain from injury. This review is focused to better understand the AD inflammatory and immunoregulatory processes to develop novel anti-inflammatory drugs to slow down the progression of AD.

Role of NF-κB in Ageing and Age-Related Diseases: Lessons from Genetically Modified Mouse Models

Ageing is a complex process, induced by multifaceted interaction of genetic, epigenetic, and environmental factors. It is manifested by a decline in the physiological functions of organisms and associated to the development of age-related chronic diseases and cancer development. It is considered that ageing follows a strictly-regulated program, in which some signaling pathways critically contribute to the establishment and maintenance of the aged state. Chronic inflammation is a major mechanism that promotes the biological ageing process and comorbidity, with the transcription factor NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) as a crucial mediator of inflammatory responses. This, together with the finding that the activation or inhibition of NF-κB can induce or reverse respectively the main features of aged organisms, has brought it under consideration as a key transcription factor that acts as a driver of ageing. In this review, we focused on the data obtained entirely through the generation of knockout and transgenic mouse models of either protein involved in the NF-κB signaling pathway that have provided relevant information about the intricate processes or molecular mechanisms that control ageing. We have reviewed the relationship of NF-κB and premature ageing; the development of cancer associated with ageing and the implication of NF-κB activation in the development of age-related diseases, some of which greatly increase the risk of developing cancer.

Does oxidatively damaged DNA drive amyloid-β generation in Alzheimer's disease? A hypothesis

In Alzheimer's disease (AD), amyloid-β (Aβ) generation and upstream β-secretase 1 (BACE1) expression appear to be driven by oxidative stress via c-Jun N-terminal kinase (JNK), p38, and Interferon-Induced, Double-Stranded RNA-Activated Protein Kinase (PKR). In addition, inflammatory molecules, including lipopolysaccharide (LPS), induce genes central to Aβ genesis, such as BACE1, via nuclear factor-κB (NFκB). However, additional triggers of Aβ generation remain poorly understood and might represent novel opportunities for therapeutic intervention. Based on mechanistic studies and elevated ectopic oxidatively damaged DNA (oxoDNA) levels in preclinical AD, mild cognitive impairment, and AD patients, we hypothesize oxoDNA contributes to β-amyloidosis starting from the earliest stages of AD through multiple pathways. OxoDNA induces mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4), thereby sensitizing the brain to oxidative stress-induced JNK activation and BACE1 transcription. It also induces myeloid differentiation primary response 88 (MyD88) and activates protein kinase CK2, thereby increasing NFκB activation and BACE1 induction. OxoDNA increases oxidative stress via nuclear factor erythroid 2-related factor 2 (Nrf2) ectopic localization, likely augmenting JNK-mediated BACE1 induction. OxoDNA likely also promotes β-amyloidosis via absent in melanoma 2 (AIM2) induction. Falsifiable predictions of this hypothesis include that deoxyribonuclease treatment should decrease Aβ and possibly slow cognitive decline in AD patients. While formal testing of this hypothesis remains to be performed, a case report has found deoxyribonuclease I treatment improved a severely demented AD patient's Mini-Mental Status Exam score from 3 to 18 at 2 months. There is preliminary preclinical and clinical evidence suggesting that ectopic oxidatively damaged DNA may act as an inflammatory damage-associated molecular pattern contributing to Aβ generation in AD, and deoxyribonuclease I should be formally evaluated to test whether it can decrease Aβ levels and slow cognitive decline in AD patients.

Action Mechanisms of Curcumin in Alzheimer's Disease and Its Brain Targeted Delivery

AD is a chronic neurodegenerative disease. Many different signaling pathways, such as Wnt/β-catenin, Notch, ROS/JNK, and PI3K/Akt/mTOR are involved in Alzheimer’s disease and crosstalk between themselves. A promising treatment involves the uses of flavonoids, and one of the most promising is curcumin; however, because it has difficulty permeating the blood–brain barrier (BBB), it must be encapsulated by a drug carrier. Some of the most frequently studied are lipid nanocarriers, liposomes, micelles and PLGA. These carriers are further conjugated with brain-targeting agents such as lactoferrin and transferrin. In this review paper, curcumin and its therapeutic effects, which have been examined in vivo, are analyzed and then the delivery systems to the brain are addressed. Overall, the analysis of the literature revealed great potential for curcumin in treating AD and indicated the challenges that require further research.