Age-related Neurodegenerative Diseases Research Articles

Investigation of the expression of long non-coding RNA in Parkinson’s disease

BackgroundParkinson’s disease is the second most common age-related neurodegenerative disease after Alzheimer’s. Pathogenic factors in Parkinson’s include inflammation and oxidative stress, which lead to dopaminergic cell apoptosis. The case–control study aims to determine the expression level of long non-coding RNAs (lncRNAs) of the apoptosis pathway in Parkinson’s patients compared to healthy individuals. In the case–control study, 50 patients with Parkinson’s disease were examined, along with 50 healthy individuals matched in age and sex. In both groups, the expression of long non-coding RNAs, including taurine upregulated 1 (TUG1), metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), nuclear-enriched abundant transcript 1 (NEAT1), and growth arrest-specific 5 (GAS5), was compared using real-time polymerase chain reaction (PCR).ResultsThe ratio of MALAT1, NEAT1, and TUG1 gene expression in the case group was statistically significantly higher than in healthy individuals. The ratio of GAS5 gene expression in people with Parkinson’s disease was lower, with a statistically significant difference. The ratio of HULC gene expression was higher in the case group, but it did not show a statistically significant difference with the control group.ConclusionThe involvement of long lncRNAs that increase apoptosis may play a role in the pathogenesis of the disease, which may be used for identification and therapeutic purposes.

Midnolin, a Genetic Risk Factor for Parkinson's Disease, Promotes Neurite Outgrowth Accompanied by Early Growth Response 1 Activation in PC12 Cells.

Parkinson's disease (PD) is an age-related progressive neurodegenerative disease. Previously, we identified midnolin (MIDN) as a genetic risk factor for PD. Although MIDN copy number loss increases the risk of PD, the molecular function of MIDN remains unclear. To investigate the role of MIDN in PD, we established monoclonal Midn knockout (KO) PC12 cell models. Midn KO inhibited neurite outgrowth and neurofilament light chain (Nefl) gene expression. Although MIDN is mainly localized in the nucleus, it does not encode DNA-binding domains. We therefore hypothesized that MIDN might bind to certain transcription factors and regulate gene expression. Of the candidate transcription factors, we focused on early growth response 1 (EGR1) because it is required for neurite outgrowth and its target genes are downregulated by Midn KO. An interaction between MIDN and EGR1 was confirmed by immunoprecipitation. Surprisingly, although EGR1 protein levels were significantly increased in Midn KO cells, the binding of EGR1 to the Nefl promoter and resulting transcriptional activity were downregulated as measured by luciferase assay and chromatin immunoprecipitation quantitative real-time polymerase chain reaction. Overall, we identified the MIDN-dependent regulation of EGR1 function. This mechanism may be an underlying reason for the neurite outgrowth defects of Midn KO PC12 cells.

Lycopene alleviates age-related cognitive deficit via activating liver-brain fibroblast growth factor-21 signalling

Brain function is linked with many peripheral tissues, including the liver, where hepatic fibroblast growth factor 21 (FGF21) mediates communication between the liver and brain. Lycopene (LYC), a naturally occurring carotenoid, posses multiple health-promoting properties, including neuroprotective function. Here, we investigated the effects of LYC on age-related memory impairment and the relative contribution of liver-brain FGF21 signaling in these process. The results showed that after treatment with LYC for 3 months, brain aging and age-related cognitive deficits were effectively managed. In addition, LYC ameliorated neuronal degeneration, mitochondrial dysfunction and synaptic damage, and promoted synaptic vesicle fusion in 18-month-old mice. Notably, LYC activated liver-brain FGF21 signalling in aging mice. Whereas all these central effects of LYC were negated by blocking FGF21 via i. v. injection of adeno-associated virus in aging mice. Furthermore, recombinant FGF21 elevated mitochondrial ATP levels and enhanced synaptic vesicle fusion in mouse hippocampal HT-22 cells, which promoted neurotransmitter release. Additionally, we co-cultured hepatocytes and neurons in Transwell and found that LYC enhanced hepatocytes’ support for neurons. This support included improved cell senescence, enhanced mitochondrial function, and increased axon length in co-cultured neurons. In conclusion, LYC protects against age-related cognitive deficit, partly explained by activating liver-brain FGF21 signalling, hence promoting neurotransmitters release via increasing mitochondrial ATP levels and enhancing synaptic vesicle fusion. These findings revealed that FGF21 could be a potential therapeutical target in nutritional intervention strategies to improve cognitive damage caused by aging and age-related neurodegenerative diseases.

Anti-infective Properties of Mung Bean (Vigna Radiata (L.)R. Wilczek) Coat Extract on Pseudomonas aeruginosa-Infected Caenorhabditis elegans: Transcriptomics and Pathway Analysis

Ethnopharmacological RelevanceMung bean coat has long been known for its wide-ranging health benefits, including antibacterial, anti-inflammatory, and immune-modulatory properties. For many years in China, mung beans have been employed in the therapeutic management of inflammation induced by pathogenic bacteria infection, yet the precise underlying protective mechanisms remain to be comprehensively elucidated. Aim of the StudyGiven the growing concern over antibiotic resistance, there is a necessity to explore new anti-infective agents. Here, the anti-infective properties of Mung bean coat extract (MBCE) were investigated using a model of Pseudomonas aeruginosa-infected nematodes. Materials and MethodsThe protective effects of MBCE on Pseudomonas aeruginosa (PA14) infected nematodes were assessed by lifespan assay, reactive oxygen species (ROS) levels, transcriptomics, and Quantitative real-time PCR (qRT-PCR). ResultsMBCE significantly improved the survival rates and reduced ROS levels in infected worms. Transcriptomic profiling disclosed predominant KEGG pathway enrichments in immune responses, energy metabolism processes such as oxidative phosphorylation and the tricarboxylic acid cycle, alongside aging-related neurodegenerative diseases and longevity regulatory pathways like PI3K-AKT, MAPK, mTOR, and FOXO. qRT-PCR validation showed that MBCE upregulated antimicrobial peptides (spp-3, lys-1, lys-7, abf-2, cnc-2, nlp-33, clec-85), gram-negative responses (irg-3, src-2, grd-3, col-179), and mitochondrial function (mev-1) gene expressions, while downregulated insulin signaling-related (age-1, akt-1, akt-2, daf-15) gene expressions. Mutant strains lifespan analysis indicated that the nsy-1, sek-1, pmk-1, daf-2, aak-2, sir-2.1, and skn-1 were necessary for lifespan extension mediated by MBCE under PA14 infection, but not clk-1, isp-1, mev-1, or daf-16. ConclusionCollectively, our findings suggested that MBCE increased the survival rates of PA14-infected worms by activating downstream antimicrobial and antioxidant gene expressions through modulation of MAPK, daf-2, aak-2, sir-2.1, and skn-1 pathways. The research underscored the potential of natural plant compounds to strengthen the body's defenses against infections, potentially mitigating harmful ROS levels and improving survival. Additionally, these findings elucidated the mechanisms by which these plant-derived compounds enhance the immune system, implying their potential utility as dietary supplements or as an alternative to conventional antibiotics.

Icariin targets p53 to protect against ceramide-induced neuronal senescence: Implication in Alzheimer's disease

BackgroundAlzheimer's disease (AD) is a leading cause of dementia. The aging brain is particularly vulnerable to various stressors, including increased levels of ceramide. However, the role of ceramide in neuronal cell senescence and AD progression and whether icariin, a natural flavonoid glucoside, could reverse neuronal senescence remain inadequately understood. AimIn this study, we explore the role of ceramide in neuronal senescence and AD, and whether icariin can counteract these effects. MethodsWe pretreated HT-22 cells with icariin and then induced senescence with ceramide. Various assays were employed to assess cell senescence, such as reactive oxygen species (ROS) production, cell cycle progression, β-galactosidase staining, and expression of senescence-associated proteins. In vivo studies utilized APP/PS1 mice and C57BL/6J mice injected with ceramide to evaluate behavioral changes, histopathological alterations, and senescence-associated protein expression. Transcriptomics, molecular docking, molecular dynamics simulations, and cellular thermal shift assays were employed to verify the interaction between icariin and P53. The specificity of icariin targeting of P53 was further confirmed through rescue experiments utilizing the P53 activator Navtemadlin. ResultsOur data demonstrated that ceramide could induce neuronal senescence and AD-related pathologies, which were reversed by icariin. Moreover, molecular studies revealed that icariin directly targeted P53, and its neuroprotective effects were attenuated by P53 activation, providing evidence for the role of P53 in icariin-mediated neuroprotection. ConclusionIcariin demonstrates a protective effect against ceramide-induced neuronal senescence by inhibiting the P53 pathway. This identifies a novel mechanism of action for icariin, offering a novel therapeutic approach for AD and other age-related neurodegenerative diseases.

Gut microbiota-brain bile acid axis orchestrates aging-related neuroinflammation and behavior impairment in mice

Emerging evidence shows that disrupted gut microbiota-bile acid (BA) axis is critically involved in the development of neurodegenerative diseases. However, the alterations in spatial distribution of BAs among different brain regions that command important functions during aging and their exact roles in aging-related neurodegenerative diseases are poorly understood. Here, we analyzed the BA profiles in cerebral cortex, hippocampus, and hypothalamus of young and natural aging mice of both sexes. The results showed that aging altered brain BA profiles sex- and region- dependently, in which TβMCA was consistently elevated in aging mice of both sexes, particularly in the hippocampus and hypothalamus. Furthermore, we found that aging accumulated-TβMCA stimulated microglia inflammation in vitro and shortened the lifespan of C. elegans, as well as behavioral impairment and neuroinflammation in mice. In addition, metagenomic analysis suggested that the accumulation of brain TβMCA during aging was partially attributed to reduction in BSH-carrying bacteria. Finally, rejuvenation of gut microbiota by co-housing aged mice with young mice restored brain BA homeostasis and improved neurological dysfunctions in natural aging mice. In conclusion, our current study highlighted the potential of improving aging-related neuro-impairment by targeting gut microbiota-brain BA axis.

Synthesis and biological evaluation of novel aminoquinolines with an n-octyl linker: Impact of halogen substituents on C(7) or a terminal amino group on anticholinesterase and BACE1 activity

Alzheimer’s disease is age-related multifactorial neurodegenerative disease manifested by gradual loss of memory, cognitive decline and changes in personality. Due to rapid and continuous growth of its prevalence, the treatment of Alzheimer’s disease calls for development of new and efficacies drugs, especially those that could be able to simultaneously act on more than one of possible targets of action. Aminoquinolines have proven to be a highly promising structural scaffold in the design of such a drug as cholinesterases and β-secretase 1 inhibitors. In this study, we synthesised twenty-two new 4-aminoquinolines with different halogen atom and its position in the terminal N-benzyl group or with a trifluoromethyl or a chlorine as C(7)-substituents on the quinoline moiety. All compounds were evaluated as multi-target-directedligands by determining their inhibition potency towards human acetylcholinesterase, butyrylcholinesterase and β-secretase 1. All of the tested derivatives were very potent inhibitors of human acetylcholinesterase and butyrylcholinesterase with inhibition constants (Ki) in the nM to low μM range. Most were estimated to be able to cross the blood–brain barrier by passive transport and were nontoxic toward cells that represented the main models of individual organs.

Genome-Wide Association Study Meta-Analysis Uncovers Novel Genetic Variants Associated with Olfactory Dysfunction.

Olfactory dysfunction is among the earliest signs of many age-related neurodegenerative diseases and has been associated with increased mortality in older adults; however, its genetic basis remains largely unknown. To identify the genetic loci associated with olfactory dysfunction in the general population. This genome-wide association study meta-analysis (GWMA) included participants of European ancestry (N = 22,730) enrolled in four different large population-based studies, followed by a multi-ancestry GWMA including participants of African ancestry (N = 1,030). The data analysis was performed from March 2023 through June 2024. Genome-wide single nucleotide polymorphisms. Olfactory dysfunction was the outcome and assessed using a 12-item smell identification test. GWMA revealed a novel genome-wide significant locus (tagged by rs11228623 at 11q12) associated with olfactory dysfunction. Gene-based analysis revealed a high enrichment for olfactory receptor genes in this region. Phenome-wide association studies demonstrated associations between genetic variants related to olfactory dysfunction and blood cell counts, kidney function, skeletal muscle mass, cholesterol levels and cardiovascular disease. Using individual-level data, we also confirmed and quantified the strength of these associations on a phenotypic level. Moreover, employing two-sample Mendelian Randomization analyses, we found evidence for causal associations between olfactory dysfunction and these phenotypes. These findings provide novel insights into the genetic architecture of the sense of smell and highlight its importance for many aspects of human health.

Modeling APOE ε4 familial Alzheimer's disease in directly converted 3D brain organoids.

Brain organoids have become a valuable tool for studying human brain development, disease modeling, and drug testing. However, generating brain organoids with mature neurons is time-intensive and often incomplete, limiting their utility in studying age-related neurodegenerative diseases such as Alzheimer's disease (AD). Here, we report the generation of 3D brain organoids from human fibroblasts through direct reprogramming, with simplicity, efficiency, and reduced variability. We also demonstrate that induced brain organoids from APOE ε4 AD patient fibroblasts capture some disease-specific features and pathologies associated with APOE ε4 AD. Moreover, APOE ε4-induced brain organoids with mutant APP overexpression faithfully recapitulate the acceleration of AD-related pathologies, providing a more physiologically relevant and patient-specific model of familial AD. Importantly, transcriptome analysis reveals that gene sets specific to APOE ε4 patient-induced brain organoids are highly similar to those of APOE ε4 post-mortem AD brains. Overall, induced brain organoids from direct reprogramming offer a promising approach for more efficient and controlled studies of neurodegenerative disease modeling.

Icariin Ameliorates D-galactose-induced Cell Injury in Neuron-like PC12 Cells by Inhibiting MPTP Opening.

Icariin (ICA) has a good neuroprotective effect and can upregulate neuronal basal autophagy in naturally aging rats. Mitochondrial dysfunction is associated with brain aging-related neurodegenerative diseases. Abnormal opening of the mitochondrial permeability transition pore (mPTP) is a crucial factor in mitochondrial dysfunction and is associated with excessive autophagy. This study aimed to explore that ICA protects against neuronal injury by blocking the mPTP opening and down-regulating autophagy levels in a D-galactose (D-gal)-induced cell injury model. A cell model of neuronal injury was established in rat pheochromocytoma cells (PC12 cells) treated with 200 mmol/L D-gal for 48 h. In this cell model, PC12 cells were pre-treated with different concentrations of ICA for 24 h. MTT was used to detect cell viability. Senescence associated β-galactosidase (SA-β-Gal) staining was used to observe cell senescence. Western blot analysis was performed to detect the expression levels of a senescence-related protein (p21), autophagy markers (LC3B, p62, Atg7, Atg5 and Beclin 1), mitochondrial fission and fusion-related proteins (Drp1, Mfn2 and Opa1), and mitophagy markers (Pink1 and Parkin). The changes of autophagic flow were detected by using mRFP-GFP-LC3 adenovirus. The intracellular ultrastructure was observed by transmission electron microscopy. Immunofluorescence was used to detect mPTP, mitochondrial membrane potential (MMP), mitochondrial reactive oxygen species (mtROS) and ROS levels. ROS and apoptosis levels were detected by flow cytometry. D-gal treatment significantly decreased the viability of PC12 cells, and markedly increased the SA-β-Gal positive cells as compared to the control group. With the D-gal stimulation, the expression of p21 was significantly up-regulated. Furthermore, D-gal stimulation resulted in an elevated LC3B II/I ratio and decreased p62 expression. Meanwhile, autophagosomes and autolysosomes were significantly increased, indicating abnormal activation of autophagy levels. In addition, in this D-gal-induced model of cell injury, the mPTP was abnormally open, the ROS generation was continuously increased, the MMP was gradually decreased, and the apoptosis was increased. ICA effectively improved mitochondrial dysfunction to protect against D-gal-induced cell injury and apoptosis. It strongly inhibited excessive autophagy by blocking the opening of the mPTP. Cotreatment with ICA and an mPTP inhibitor (cyclosporin A) did not ameliorate mitochondrial dysfunction. However, the protective effects were attenuated by cotreatment with ICA and an mPTP activator (lonidamine). ICA inhibits the activation of excessive autophagy and thus improves mitochondrial dysfunction by blocking the mPTP opening.

Insights Into the Role of Copper in Neurodegenerative Diseases and the Therapeutic Potential of Natural Compounds.

Neurodegenerative diseases encompass a collection of neurological disorders originating from the progressive degeneration of neurons, resulting in the dysfunction of neurons. Unfortunately, effective therapeutic interventions for these diseases are presently lacking. Copper (Cu), a crucial trace element within the human body, assumes a pivotal role in various biological metabolic processes, including energy metabolism, antioxidant defense, and neurotransmission. These processes are vital for the sustenance, growth, and development of organisms. Mounting evidence suggests that disrupted copper homeostasis contributes to numerous age-related neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS), Wilson's disease (WD), Menkes disease (MD), prion diseases, and multiple sclerosis (MS). This comprehensive review investigates the connection between the imbalance of copper homeostasis and neurodegenerative diseases, summarizing pertinent drugs and therapies that ameliorate neuropathological changes, motor deficits, and cognitive impairments in these conditions through the modulation of copper metabolism. These interventions include Metal-Protein Attenuating Compounds (MPACs), copper chelators, copper supplements, and zinc salts. Moreover, this review highlights the potential of active compounds derived from natural plant medicines to enhance neurodegenerative disease outcomes by regulating copper homeostasis. Among these compounds, polyphenols are particularly abundant. Consequently, this review holds significant implications for the future development of innovative drugs targeting the treatment of neurodegenerative diseases.

Aberrant blood-brain barrier dynamics in cerebral small vessel disease - a review of associations, pathomechanisms and therapeutic potentials

This review explores the pivotal role of the blood-brain barrier (BBB) in maintaining central nervous system (CNS) homeostasis and its dynamic involvement in the pathogenesis of cerebral small vessel disease (CSVD), i.e., the major precursor of age-related neurodegenerative diseases such as vascular dementia and Alzheimer’s disease. It underscores the BBB as a critical physiological boundary that regulates the exchange between the bloodstream and the cerebral milieu through a complex and dynamic interface composed of endothelial cells, astrocyte endfeet, and pericytes. The integrity of this barrier is paramount for neural function, shielding the brain from toxicants and pathogens while facilitating the transport of essential nutrients. Nevertheless, BBB dysfunction is recognized as a lead in the pathogenesis of neurodegeneration including CSVD, emphasizing the need for focused research on maintaining or restoring BBB function. This review highlights recent advancements in our understanding of BBB dynamics in both health and disease states, its involvement in CSVD pathomechanisms, and the challenges and future directions of translational research and emerging technologies. The review advocates for a multidisciplinary approach to uncover the complexity of BBB dysfunction in CSVD, as well as insights into potential therapeutic targets aimed at preserving BBB integrity, thereby minimizing its impact given the notable world’s aging demographics.

Neuronal regulated cell death in aging-related neurodegenerative diseases: key pathways and therapeutic potentials.

Regulated cell death (such as apoptosis, necroptosis, pyroptosis, autophagy, cuproptosis, ferroptosis, disulfidptosis) involves complex signaling pathways and molecular effectors, and has been proven to be an important regulatory mechanism for regulating neuronal aging and death. However, excessive activation of regulated cell death may lead to the progression of aging-related diseases. This review summarizes recent advances in the understanding of seven forms of regulated cell death (RCD) in age-related diseases. Notably, the newly identified ferroptosis and cuproptosis have been implicated in the risk of cognitive impairment and neurodegenerative diseases. These forms of cell death exacerbate disease progression by promoting inflammation, oxidative stress, and pathological protein aggregation. The review also provides an overview of key signaling pathways and crosstalk mechanisms among these RCD forms, with a focus on ferroptosis, cuproptosis, and disulfidptosis. For instance, FDX1 directly induces cuproptosis by regulating copper ion valency and dihydrolipoamide S-acetyltransferase (DLAT) aggregation, while copper mediates glutathione peroxidase 4 (GPX4) degradation, enhancing ferroptosis sensitivity. Additionally, inhibiting the Xc- transport system to prevent ferroptosis can increase disulfide formation and shift the NADP+/NADPH ratio, transitioning ferroptosis to disulfidptosis. These insights help to uncover the potential connections among these novel RCD forms and differentiate them from traditional RCD mechanisms. In conclusion, identifying key targets and their crosstalk points among various RCD pathways may aid in developing specific biomarkers to reverse the aging clock and treat age-related neurodegenerative conditions.

Increased copy-number variant load of associated risk genes in sporadic cases of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is an age-related neurodegenerative disease characterized by selective loss of motor neurons in the brainstem and spinal cord. Several genetic factors have been associated to ALS, ranging from causal genes and potential risk factors to disease modifiers. The search for pathogenic variants in these genes has mostly focused on single nucleotide variants (SNVs) while relatively understudied and not fully elucidated is the contribution of structural variants, such as copy number variations (CNVs). Here, we applied an exon-centric aCGH method to investigate, in sporadic ALS patients, the load of CNVs in 131 genes previously associated to ALS. Our approach revealed that CNV load, defined as the total number of CNVs or their size, was significantly higher in ALS cases than controls. About 87% of patients harbored multiple CNVs in ALS-related genes, and 75% structural variants compromised genes directly implicated in ALS pathogenesis (C9orf72, CHCHD10, EPHA4, FUS, HNRNPA1, KIF5A, NEK1, OPTN, PFN1, SOD1, TARDBP, TBK1, UBQLN2, UNC13A, VAPB, VCP). CNV load was also associated to higher onset age and disease progression rate. Although the contribution of individual CNVs in ALS is still unknown, their extensive load in disease-related genes may have relevant implications for the diagnostic, prognostic and therapeutical management of this devastating disorder.

Targeting Mitochondrial Dysfunction and Reactive Oxygen Species for Neurodegenerative Disease Treatment.

Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common neurodegenerative diseases, and they affect millions of people worldwide, particularly older individuals. Therefore, there is a clear need to develop novel drug targets for the treatment of age-related neurodegenerative diseases. Emerging evidence suggests that mitochondrial dysfunction and reactive oxygen species (ROS) generation play central roles in the onset and progression of neurodegenerative diseases. Mitochondria are key regulators of respiratory function, cellular energy adenosine triphosphate production, and the maintenance of cellular redox homeostasis, which are essential for cell survival. Mitochondrial morphology and function are tightly regulated by maintaining a balance among mitochondrial fission, fusion, biogenesis, and mitophagy. In this review, we provide an overview of the main functions of mitochondria, with a focus on recent progress highlighting the critical role of ROS-induced oxidative stress, dysregulated mitochondrial dynamics, mitochondrial apoptosis, mitochondria-associated inflammation, and impaired mitochondrial function in the pathogenesis of age-related neurodegenerative diseases, such as AD and PD. We also discuss the potential of mitochondrial fusion and biogenesis enhancers, mitochondrial fission inhibitors, and mitochondria-targeted antioxidants as novel drugs for the treatment of these diseases.

Age-related energetic reprogramming in glial cells: possible correlations with Parkinson’s disease

Glial cells populate the central nervous system and undertake indispensable roles in safeguarding and maintaining optimal neuronal performance. Throughout life, the brain undergoes inevitable changes that impact both neurons and glial cells. Concurrent with age-related neurodegenerative diseases, such as Alzheimer’s disease (AD) and Parkinson’s disease (PD), metabolic dysfunctions in glial cells are consistently observed. Though widely debated, the idea of treating neurodegenerative disorders by manipulating brain bioenergetics warrants further exploration. This review discusses the distinctive metabolic characteristics of central nervous system (CNS) glia, the metabolic deviations that occur in glial cells in the aging brain, and the ramifications of metabolic rewiring within glia on neurodegenerative disorders, specifically PD. We focus on astrocytes and microglia due to their substantial transformations under aging and diseased states, known as reactivation. Special attention is given to clarifying the complex relationships between dysregulated glial energy metabolism and brain disorders. By discussing both classic theories and current advances in this field, we aim to shed light on promising therapeutic horizons anchored in the strategic calibration of glial metabolic configurations.

Human fibroblasts from sporadic Alzheimer's disease (AD) patients show mitochondrial alterations and lysosome dysfunction

Mitophagy is a mechanism that maintains mitochondrial integrity and homeostasis and is thought to promote longevity and reduce the risk of age-related neurodegenerative diseases, including Alzheimer's disease (AD). Here, we investigate the abundance of mitochondrial reactive oxygen species (ROS), mitochondrial function, and mitophagy in primary fibroblasts from patients with sporadic AD (sAD) and normal healthy controls. The results show increased levels of mitochondrial ROS, changes in mitochondrial morphology, altered bioenergetic properties, and defects in autophagy, mitophagy, and lysosome-mediated degradation pathways in sAD fibroblasts relative to control fibroblasts. Interestingly, lysosome abundance and the staining of lysosomal markers remained high, while the capacity of lysosome-dependent degradation was lower in sAD fibroblasts than in controls fibroblasts. Nicotinamide riboside supplementation decreased mitochondrial ROS, while capacity for lysosomal degradation remained unchanged in sAD fibroblasts relative to healthy control fibroblasts. These findings provide insight into molecular mechanisms involving the dysregulation of lysosome and autophagy/mitophagy pathways that may contribute significantly to clinical signs and pathological features of sAD.

Effectiveness and mechanisms of combined use of antioxidant nutrients in protecting against oxidative stress-induced neuronal loss and related neurological deficits.

Oxidative stress is a well-known pathological factor driving neuronal loss and age-related neurodegenerative diseases. Melatonin, coenzyme Q10 and lecithin are three common nutrients with an antioxidative capacity. Here, we examined the effectiveness of them administrated individually and in combination in protecting against oxidative stress-induced neuronal death invitro, and neurodegenerative conditions such as Alzheimer's disease and associated deficits invivo. Mouse neuroblastoma Neuro-2a (N2a) cells were exposed with H2O2 for 6 h, and subsequently treated with melatonin, coenzyme Q10, and lecithin alone or in combination for further 24 h. Cell viability was assessed using the CCK-8 assay. Eight-week-old male mice were intraperitoneally injected with D-(+)-galactose for 10 weeks and administrated with melatonin, coenzyme Q10, lecithin, or in combination for 5 weeks starting from the sixth week, followed by behavioral tests to assess the effectiveness in mitigating neurological deficits, and biochemical assays to explore the underlying mechanisms. Exposure to H2O2 significantly reduced the viability of N2a cells and increased oxidative stress and tau phosphorylation, all of which were alleviated by treatment with melatonin, coenzyme Q10, lecithin alone, and, most noticeably, by combined treatment. Administration of mice with D-(+)-galactose-induced oxidative stress and tau phosphorylation, brain aging, impairments in learning and memory, anxiety- and depression-like behaviors, and such detrimental effects were mitigated by melatonin, coenzyme Q10, lecithin alone, and, most consistently, by combined treatment. These results suggest that targeting oxidative stress via supplementation of antioxidant nutrients, particularly in combination, is a better strategy to alleviate oxidative stress-mediated neuronal loss and brain dysfunction due to age-related neurodegenerative conditions.

Relationship of Curcumin with Aging and Alzheimer and Parkinson Disease, the Most Prevalent Age-Related Neurodegenerative Diseases: A Narrative Review.

The elderly population is increasing worldwide every day. Age is a significant factor in the progression of neurological diseases, which can also cause cognitive decline and memory disorders. Inflammation and oxidative stress are primary drivers of senescence and disorders, particularly those associated with aging and neurodegenerative diseases. Bioactive phytochemicals are considered a promising therapeutic strategy in combating aging and age-related pathological conditions. One of the phytochemicals with diverse biological properties encompassing antioxidant, anti-inflammatory, antibacterial, antiviral, anticancer, antifungal, antidepressant, anti-allergic, and anti-aging properties is curcumin. Curcumin, a polyphenolic structure with a distinct orange hue and unique chemical properties, is derived from the roots of Curcuma longa, a member of the Zingiberaceae family, commonly known as turmeric. It has been noted that the incidence of neurodegenerative diseases is low in societies that consume curcumin widely. Therefore, this review investigates the effect of curcumin on aging and Alzheimer and Parkinson disease, which are the most prevalent age-related neurodegenerative diseases.

Changes in mitochondrial distribution occur at the axon initial segment in association with neurodegeneration in Drosophila.

Changes in mitochondrial distribution are a feature of numerous age-related neurodegenerative diseases. In Drosophila, reducing the activity of Cdk5 causes a neurodegenerative phenotype and is known to affect several mitochondrial properties. Therefore, we investigated whether alterations of mitochondrial distribution are involved in Cdk5-associated neurodegeneration. We find that reducing Cdk5 activity does not alter the balance of mitochondrial localization to the somatodendritic versus axonal neuronal compartments of the mushroom body, the learning and memory center of the Drosophila brain. We do, however, observe changes in mitochondrial distribution at the axon initial segment (AIS), a neuronal compartment located in the proximal axon involved in neuronal polarization and action potential initiation. Specifically, we observe that mitochondria are partially excluded from the AIS in wild-type neurons, but that this exclusion is lost upon reduction of Cdk5 activity, concomitant with the shrinkage of the AIS domain that is known to occur in this condition. This mitochondrial redistribution into the AIS is not likely due to the shortening of the AIS domain itself but rather due to altered Cdk5 activity. Furthermore, mitochondrial redistribution into the AIS is unlikely to be an early driver of neurodegeneration in the context of reduced Cdk5 activity.