Mitochondrial Dysfunction and Oxidative Stress in Alzheimer's Disease

Reduced 17β-estradiol following ovariectomy induces mitochondrial dysfunction and degradation of synaptic proteins in the entorhinal cortex

Reductions in circulating estrogens can contribute to cognitive decline, in part by impairing mitochondrial function within the hippocampal region. The entorhinal cortex provides the hippocampus with its main cortical inputs. To assess the impact of estrogen deficiency on mitochondrial respiration and synaptic proteins in the entorhinal cortex, female wildtype rats received either sham surgery, bilateral ovariectomy, or ovariectomy with implantation of a subdermal capsule to maintain low levels of circulating 17β-estradiol (E2). Mitochondrial respiration in the entorhinal cortex was not significantly affected two weeks following ovariectomy, but there was a reduction in oxygen consumption four weeks after ovariectomy that was prevented by E2 supplementation. The expression of mitochondrial membrane integrity element voltage-dependent anion channel protein (VDAC1) was also reduced four weeks after ovariectomy, suggesting that respiration was reduced due to a decline in mitochondrial density. Ovariectomy also increased mitochondrial and cytoplasmic cytochrome c and upregulated superoxide dismutase 2 (SOD2) both two and four weeks after ovariectomy, reflecting mitochondrial electron leakage and oxidative redox imbalance. Further, the ovariectomy-induced changes in mitochondrial proteins were associated with reductions in postsynaptic density protein 95 (PSD95) and the presynaptic protein synaptophysin. There were no changes in mitochondrial or synaptic proteins in ovariectomized animals that received E2 supplementation. Our findings indicate that reductions in circulating 17β-estradiol induced by ovariectomy disrupt mitochondrial functions in the entorhinal cortex, and suggest that a resulting increase in oxidative stress contributes to the degradation in synaptic proteins that may affect cognitive functions mediated by the hippocampal region.

Advancements in nose-to-brain drug targeting for Alzheimer's disease: a review of nanocarriers and clinical insights

Alzheimer's disease (AD) is a type of neurodegenerative disease that describes cognitive decline and memory loss resulting in disability in movement, memory, speech etc. Which first affects the hippocampal and entorhinal cortex regions of brain. Pathogenesis of AD depends on Amyloid-β, hyper-phosphorylation of tau protein, mitochondrial dysfunction, cholinergic hypothesis and oxidative stress. In comparison with males, females are more prone to AD due to reduced estrogen level. Some of the FDA-approved drugs and their conventional formulations available in the market are discussed in this review. Nose-to-brain delivery system provides the target specific drug delivery via olfactory and trigeminal nerve (active and passive drug targeting strategies) and bypassing the Blood Brain Barrier. Mucoadhesive agents and permeation enhancers are mostly utilized to enhance the retention time and bioavailability of the drugs. Liposomes, niosomes, cubosomes, solid lipid nanoparticles, nanoemulsions, micelles, and many more nanocarriers for nose-to-brain delivery of drugs are also described thoroughly in this review. It also covers the clinical trials and patents for nose-to-brain delivery. In this article, we investigate the nose-to-brain pathways for AD treatment strategies.

Scientific investigation of non-coding RNAs in mitochondrial epigenetic and aging disorders: Current nanoengineered approaches for their therapeutic improvement

Genetic control is vital for the growth of cells and tissues, and it also helps living things, from single-celled organisms to complex creatures, maintain a stable internal environment. Within cells, structures called mitochondria act like tiny power plants, producing energy and keeping the cell balanced. The two primary categories of RNA are messenger RNA (mRNA) and non-coding RNA (ncRNA). mRNA carries the instructions for building proteins, while ncRNA does various jobs at the RNA level. There are different kinds of ncRNA, each with a specific role. Some help put RNA molecules together correctly, while others modify other RNAs or cut them into smaller pieces. Still others control how much protein is made from a gene. Scientists have recently discovered many more ncRNAs than previously known, and their functions are still being explored. This article analyzes the RNA molecules present within mitochondria, which have a crucial purpose in the operation of mitochondria. We'll also discuss how genes can be turned on and off without changing their DNA code, and how this process might be linked to mitochondrial RNA. Finally, we'll explore how scientists are using engineered particles to silence genes and develop new treatments based on manipulating ncRNA.

Long-term taurine supplementation regulates brain mitochondrial dynamics in mice

BACKGROUND

Taurine (TAU) is the most abundant non-protein amino acid in the central nervous system (CNS). However, the molecular mechanism of TAU in the CNS is still poorly understood. Meanwhile, disruption in mitochondrial dynamics is evident in CNS disorders. This study aimed to investigate the effect of TAU on mitochondrial dynamics.

METHODS

TAU (0.25, 0.5 and 1% in drinking water) was administered to young mice for six months. Several memory/cognition parameters and indices of anxiety/depression were assessed. Meanwhile, various mitochondrial indices and the expression/activity of genes involved in mitochondrial biogenesis and dynamics (Akt, CREB, NRF1, TFAM, PGC-1α, Mfn1, Mfn2, UCP2, PINK1, OPA1, Drp1 and Fis1) were examined.

RESULTS

TAU significantly enhanced memory performance, suppressed anxiety and depression-like behaviour, increased mitochondrial biogenesis/dynamics and improved mitochondrial indices. It should be mentioned that there was no significant difference between different concentrations of TAU in changing most brain mitochondrial dynamic biomarkers in the current study.

CONCLUSIONS

These findings offer more insights into the molecular mechanism for TAU's action in the CNS. However, there is a need for further research to confirm these effects in humans. Overall, this study suggests the potential application of TAU in various neurological disorders and the need for clinical studies on the effects of this amino acid in the brain.

Discovery of gallic acid-based mitochondriotropic antioxidant attenuates LPS-induced neuroinflammation

Mitochondria are complex organelle that plays a pivotal role in energy metabolism, regulation of stress responses, and also serve as a major hub for biosynthetic processes. In addition to their well-established function in cellular energetics, it also serves as the primary site for the origin of intracellular reactive oxygen species (ROS), which function as signaling molecules and can lead to oxidative stress when generated in excess. Moreover, mitochondrial dysfunction is one of the leading cause of neuroinflammation. In this regard, we have rationally designed a triazine derived mitochondriotropic antioxidants (Mito-TBA), based on gallic acid and triphenylphosphonium (TPP) cation to specifically target mitochondria to mitigate neuroinflammation. In vitro Mito-TBA-3 inhibits mitoautophagy, offers neuroprotection by inhibiting the LPS induced TLR-4 activation and activating the Nrf-2/ARE pathway in PC-12 derived neurons. In vivo Mito-TBA-3 rescue memory deficit, reversed depression like behavior, inhibited neuroinflammation, and decreased proinflammatory cytokines in LPS induced neuroinflammation rat model. Overall, based on biophysical, in vitro and in vivo analysis, Mito-TBA-3 offers valuable insights as a potent therapeutic lead molecule to combat neurodegeneration even outperforming a well-known non-steroidal anti-inflammatory drug (Aspirin), it also has the potential to use as a promising therapeutic candidate for other mitochondrial oxidative stress related disorders.

The Interplay Between Accumulation of Amyloid-Beta and Tau Proteins, PANoptosis, and Inflammation in Alzheimer's Disease

Alzheimer's disease (AD) is a common progressive neurodegenerative disorder, and the vast majority of cases occur in elderly patients. Recently, the accumulation of Aβ and tau proteins has drawn considerable attention in AD research. This review explores the multifaceted interactions between these proteins and their contribution to the pathological landscape of AD, encompassing synaptic dysfunction, neuroinflammation, and PANoptosis. PANoptosis is a collective term for programmed cell death (PCD) modalities that encompass elements of apoptosis, pyroptosis, and necroptosis. The accumulation of Aβ peptides and tau proteins, along with the immune response in brain cells, may trigger PANoptosis, thus advancing the progression of the disease. Recent advancements in molecular imaging and genetics have provided deeper insights into the interactions between Aβ peptides, tau proteins, and the immune response. The review also discusses the role of mitochondrial dysregulation in AD. The exploration of the interplay between neurodegeneration, immune responses, and cell death offers promising avenues for the development of innovative treatments.

Nuclear respiratory factor-1 (NRF1) induction drives mitochondrial biogenesis and attenuates amyloid beta-induced mitochondrial dysfunction and neurotoxicity

Mitochondrial dysfunction is an important driver of neurodegeneration and synaptic abnormalities in Alzheimer's disease (AD). Amyloid beta (Aβ) in mitochondria leads to increased reactive oxygen species (ROS) production, resulting in a vicious cycle of oxidative stress in coordination with a defective electron transport chain (ETC), decreasing ATP production. AD neurons exhibit impaired mitochondrial dynamics, evidenced by fusion and fission imbalances, increased fragmentation, and deficient mitochondrial biogenesis, contributing to fewer mitochondria in brains of AD patients. Nuclear respiratory factor-1 (NRF1) is a regulator of mitochondrial biogenesis through its activation of mitochondrial transcription factor A (TFAM). Our hypothesis posited that NRF1 induction in neuronal cells exposed to amyloid β1-42 (Aβ1-42) would increase de novo mitochondrial synthesis and improve mitochondrial function, restoring neuronal survival. Following NRF1 messenger RNA (mRNA) transfection of Aβ1-42-treated SH-SY5Y cells, a marked increase in mitochondrial mass was observed. Metabolic programming toward enhanced oxidative phosphorylation resulted in increased ATP production. Oxidative stress in the form of mitochondrial ROS accumulation was reduced and mitochondrial membrane potential preserved. Mitochondrial homeostasis was maintained, evidenced by balanced fusion and fission processes. Ultimately, improvement of mitochondrial function was associated with significant decreases in Aβ1-42-induced neuronal death and neurite disruption. Our findings highlight the potential of NRF1 upregulation to counteract Aβ1-42-associated mitochondrial dysfunction and neurodegenerative cell processes, opening avenues for innovative therapeutic approaches aimed at safeguarding mitochondrial health in AD neurons.

Electromagnetic Radiation and Biophoton Emission in Neuronal Communication and Neurodegenerative Diseases

The intersection of electromagnetic radiation and neuronal communication, focusing on the potential role of biophoton emission in brain function and neurodegenerative diseases is an emerging research area. Traditionally, it is believed that neurons encode and communicate information via electrochemical impulses, generating electromagnetic fields detectable by EEG and MEG. Recent discoveries indicate that neurons may also emit biophotons, suggesting an additional communication channel alongside the regular synaptic interactions. This dual signaling system is analyzed for its potential in synchronizing neuronal activity and improving information transfer, with implications for brain-like computing systems. The clinical relevance is explored through the lens of neurodegenerative diseases and intrinsically disordered proteins, where oxidative stress may alter biophoton emission, offering clues for pathological conditions, such as Alzheimer's and Parkinson's diseases. The potential therapeutic use of Low-Level Laser Therapy (LLLT) is also examined for its ability to modulate biophoton activity and mitigate oxidative stress, presenting new opportunities for treatment. Here, we invite further exploration into the intricate roles the electromagnetic phenomena play in brain function, potentially leading to breakthroughs in computational neuroscience and medical therapies for neurodegenerative diseases.

The Mitochondria-Targeted Micelle Inhibits Alzheimer's Disease Progression by Alleviating Neuronal Mitochondrial Dysfunction and Neuroinflammation

Mitochondrial dysfunction plays an important role in neuroinflammation and cognitive impairment in Alzheimer's disease (AD). Herein, this work designs a mitochondria-targeted micelle CsA-TK-SS-31 (CTS) to block the progression of AD by simultaneously alleviating mitochondrial dysfunction in microglia and neurons. The mitochondria-targeted peptide SS-31 drives cyclosporin A (CsA) to penetrate the blood-brain barrier (BBB) and delivers CsA to mitochondria of microglia and neurons in the brains of 5 × FAD mice. Under the high level of reactive oxygen species (ROS) environment in damaged mitochondria of microglia and neurons, the linker (thioketal, TK) between CsA and SS-31 is broken and CsA and SS-31 are released while consuming ROS in the microenvironment. The released CsA and SS-31 synergistically restore the mitochondrial membrane potential and the balance between the fission and fusion of mitochondria, which subsequently protect neurons from apoptosis and reduce the activation of microglia in the brains of 5 × FAD mice. Ultimately, the neuroinflammation and cognitive impairment of 5 × FAD mice are ameliorated. This research provides a synergistic treatment strategy for AD through alleviating mitochondrial dysfunction to reduce neuroinflammation and restore the function of neurons simultaneously.

Effects of idebenone on cognitive function and serum biomarkers in patients with amnestic mild cognitive impairment

OBJECTIVES

This retrospective study aimed to investigate the effects of idebenone on cognitive function and serum levels of superoxide dismutase (SOD) and high-sensitivity C-reactive protein (hs-CRP) in individuals with amnestic mild cognitive impairment (aMCI).

METHODS

Retrospective data were collected from the Neurology outpatient department of Liaocheng People's Hospital from January 2021 to June 2023. Patients with a newly diagnosed aMCI who received treatment were included in the idebenone treatment group. The treatment group took 30 mg of oral idebenone three times a day for 6 months. A control group of 51 MCI patients who did not receive cholinesterase inhibitors or other cognitive-enhancing drugs during the period was selected. Cognitive function assessments and serum Biomarkers were conducted before and after treatment in both groups.

RESULTS

MoCA scores were significantly improved after 6 months of idebenone treatment, and the difference was statistically significant. The delayed recall score was significantly improved, and the difference was statistically significant; The level of SOD increased and the level of high-sensitivity C-reactive protein decreased after the treatment, but there was no significant change in the control group.

CONCLUSIONS

The results of this study demonstrate that idebenone treatment significantly improves cognitive function in individuals with aMCI, particularly in the domain of delayed memory. In addition, idebenone reduces the degree of inflammation and oxidative stress and improves antioxidant levels. These findings suggest that idebenone may be a promising intervention for the management of cognitive impairments associated with aMCI.

The AICD interactome: implications in neurodevelopment and neurodegeneration

The pathophysiological mechanism involving the proteolytic processing of amyloid precursor protein (APP) and the generation of amyloid plaques is of significant interest in research on Alzheimer's disease (AD). The increasing significance of the downstream AD-related pathophysiological mechanisms has sparked research interest in other products of the APP processing cascades, including the APP intracellular domain (AICD). The potential importance of AICD in various cellular processes in the central nervous system has been established through the identification of its interactors. The interaction between AICD and its physiological binding partners is implicated in cellular events including regulation of transcriptional activity, cytoskeletal dynamics, neuronal growth, APP processing and cellular apoptosis. On the contrary, AICD is also implicated in neurodegeneration, which is a potential outcome of the functional fluctuation of AICD-mediated neuronal processes within the neuronal network. In this review, we summarize the neuronal functions and pathological manifestations of the dynamic AICD interaction network.

Proteostasis disruption and senescence in Alzheimer's disease pathways to neurodegeneration

Alzheimer's Disease (AD) is a progressive neurological disease associated with behavioral abnormalities, memory loss, and cognitive impairment that cause major causes of dementia in the elderly. The pathogenetic processes cause complex effects on brain function and AD progression. The proper protein homeostasis, or proteostasis, is critical for cell health. AD causes the buildup of misfolded proteins, particularly tau and amyloid-beta, to break down proteostasis, such aggregates are toxic to neurons and play a critical role in AD pathogenesis. The rise of cellular senescence is accompanied by aging, marked by irreversible cell cycle arrest and the release of pro-inflammatory proteins. Senescent cell build-up in the brains of AD patients exacerbates neuroinflammation and neuronal degeneration. These cells senescence-associated secretory phenotype (SASP) also disturbs the brain environment. When proteostasis failure and cellular senescence coalesce, a cycle is generated that compounds each other. While senescent cells contribute to proteostasis breakdown through inflammatory and degradative processes, misfolded proteins induce cellular stress and senescence. The principal aspects of the neurodegenerative processes in AD are the interaction of cellular senescence and proteostasis failure. This review explores the interconnected roles of proteostasis disruption and cellular senescence in the pathways leading to neurodegeneration in AD.

Inflammation and DNA methylation in Alzheimer's disease: mechanisms of epigenetic remodelling by immune cell oxidants in the ageing brain

Alzheimer's disease is a neurodegenerative disease involving memory impairment, confusion, and behavioural changes. The disease is characterised by the accumulation of amyloid beta plaques and neurofibrillary tangles in the brain, which disrupt normal neuronal function. There is no known cure for Alzheimer's disease and due to increasing life expectancy, occurrence is projected to rise over the coming decades. The causes of Alzheimer's disease are multifactorial with inflammation, oxidative stress, genetic and epigenetic variation, and cerebrovascular abnormalities among the strongest contributors. We review the current literature surrounding inflammation and epigenetics in Alzheimer's disease, with a focus on how oxidants from infiltrating immune cells have the potential to alter DNA methylation profiles in the ageing brain.

New insight on the potential detrimental effect of metabolic syndrome on the Alzheimer disease neuropathology: Mechanistic role

The metabolic syndrome or syndrome X is a clustering of different components counting insulin resistance (IR), glucose intolerance, visceral obesity, hypertension and dyslipidemia. It has been shown that IR and dysregulation of insulin signalling play a critical role in the development of metabolic syndrome by initiating the pathophysiology of metabolic syndrome through induction of glucolipotoxicity, impairment of glucose disposal and triggering of pro-inflammatory response. Furthermore, metabolic syndrome unfavourably affects the cognitive function and the development of different neurodegenerative diseases such as Alzheimer disease (AD) by inducing oxidative stress, neuroinflammation and brain IR. These changes together with brain IR impair cerebrovascular reactivity leading to cognitive impairment. In addition, metabolic syndrome increases the risk for the development of AD. However, the central mechanisms by which metabolic syndrome amplify AD risk are not completely elucidated. Consequently, this narrative review aims to revise from published articles the association between metabolic syndrome and AD regarding cellular and subcellular pathways. In conclusion, metabolic syndrome is regarded as a potential risk factor for the induction of AD neuropathology by different signalling pathways such as initiation of brain IR, activation of inflammatory signalling pathways and neuroinflammation.

Deteriorated thiol-disulphide and oxidized-reduced glutathione status in blood in Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is a steadily advancing neurodegenerative condition, the occurrence and prevalence of which are on the rise in various populations. Suspected factors contributing to its development encompass the buildup of amyloid β (Aβ) plaques, the formation of neurofibrillary tangles induced by tau proteins, and heightened oxidative stress. In this study, we aimed to evaluate intra-cellular glutathione status and extracellular thiol-disulphide status in patients with AD.

METHODS

Adult patients (>60 years old) diagnosed with AD based on DSM-IV diagnostic criteria were included in the study. Patients were divided into 3 groups as mild, moderate and severe according to Mini Mental Status Examination (MMSE) and clinical findings. Extracellular thiol-disulfide and intracellular oxidized-reduced glutathione status parameters for patient and control groups were analyzed before and after reduction procedures by using reaction of thiol groups with DTNB.

RESULTS

The reduced forms of both balances (native thiol (NT) and reduced glutathione (GSH)) were significantly lower in the patient group than the control group (p = 0.031 and <0.001, respectively), while oxidized forms (disulphide (SS) and oxidized glutathione (GSSG)) and SS/NT and GSSG/GSH percent ratios were significantly higher (p < 0.05 for all). The disease duration and oxidative stress were significantly higher in the severe group of AD. There was a shift in intracellular and extracellular thiol balances towards the oxidized side, along with correlations between MMSE and these balances (rho = -0.412 for SS/NT and rho = -0.488 for GSSG/GSH), with GSSG/GSH identified as a significant predictive factor (odds ratio (95 % confidence interval): 1.352 (1.136-1.610) for the moderate group and 1.829 (1.451-2.305) for the severe group.

CONCLUSIONS

These findings suggest that blood redox balance is disrupted in AD.

Recent advances in nanoenzymes for Alzheimer's disease treatment

Alzheimer's disease (AD) remains one of the most challenging neurodegenerative disorders to treat, with oxidative stress playing a significant role in its pathology. Recent advancements in nanoenzymes technology offer a promising approach to mitigate this oxidative damage. Nanoenzymes, with their unique enzyme-mimicking activities, effectively scavenge reactive oxygen species and reduce oxidative stress, thereby providing neuroprotective effects. This review delves into the underlying mechanisms of AD, focusing on oxidative stress and its impact on disease progression. We explore the latest developments in nanoenzymes applications for AD treatment, highlighting their multifunctional capabilities and potential for targeted delivery to amyloid-beta plaques. Despite the exciting prospects, the clinical translation of nanoenzymes faces several challenges, including difficulties in brain targeting, consistent quality production, and ensuring safety and biocompatibility. We discuss these limitations in detail, emphasizing the need for rigorous evaluation and standardized protocols. This paper aims to provide a comprehensive overview of the current state of nanoenzymes research in AD, shedding light on both the opportunities and obstacles in the path towards effective clinical applications.

The fate of neuronal synapse homeostasis in aging, infection, and inflammation

Neuroplasticity is the brain's ability to reorganize and modify its neuronal connections in response to environmental stimuli, experiences, learning, and disease processes. This encompasses a variety of mechanisms, including changes in synaptic strength and connectivity, the formation of new synapses, alterations in neuronal structure and function, and the generation of new neurons. Proper functioning of synapses, which facilitate neuron-to-neuron communication, is crucial for brain activity. Neuronal synapse homeostasis, which involves regulating and maintaining synaptic strength and function in the central nervous system (CNS), is vital for this process. Disruptions in synaptic balance, due to factors like inflammation, aging, or infection, can lead to impaired brain function. This review highlights the main aspects and mechanisms underlying synaptic homeostasis, particularly in the context of aging, infection, and inflammation.

Exploring the Therapeutic Potential of BBB-Penetrating Phytochemicals With p38 MAPK Modulatory Activity in Addressing Oxidative Stress-Induced Neurodegenerative Disorders, With a Focus on Alzheimer's Disease

Oxidative stress plays an important role in the occurrence of neurodegenerative diseases. Previous studies indicate a strong connection between oxidative stress, inappropriate activation of the p38 MAPK signaling pathway, and the pathogenesis of neurodegenerative diseases. Although antioxidant therapy is a valid strategy to alleviate these problems, the most important limitation of this approach is the ineffectiveness of drug administration due to the limited permeability of the BBB. Therefore, BBB-penetrating p38 MAPK modulators with proper antioxidant capacity could be useful in preventing/reducing the complications of neurodegenerative disorders. The current manuscript aims to review the therapeutic capabilities of some recently reviewed naturally occurring p38 MAPK inhibitors in the management of neurodegenerative problems such as Alzheimer's disease. In data collection, we tried to use more recent studies published in high-quality journals indexed in databases Scopus, Web of Science, PubMed, and so on, but no specific time frame was considered due to the nature of the study. Our evaluations indicate that natural compounds tanshinones, protoberberines, pinocembrin, osthole, rhynchophylline, oxymatrine, schisandrin, piperine, paeonol, ferulic acid, 6-gingerol, obovatol, and trolox have significant potential for use as supplements/adjuvants in the reduction of neurodegenerative-related problems. Our findings emphasize the usefulness of BBB-penetrating phytochemicals with p38 MAPK modulatory activity as potential therapeutic options against neurodegenerative disorders. Of course, the proper use of these compounds depends on considering their toxicity/safety profile and pharmacokinetic characteristics as well as the clinical conditions of users.

Effect of bioactive extracts from Eucalyptus globulus leaves in experimental models of Alzheimer's disease

Current therapies for Alzheimer's disease (AD) do not delay its progression, therefore, novel disease-modifying strategies are urgently needed. Recently, an increasing number of compounds from natural origin with protective properties against AD have been identified. Mixtures or extracts obtained from natural products containing several bioactive compounds have multifunctional properties and have drawn the attention because multiple AD pathways can be simultaneously modulated. This study evaluated the in vitro and in vivo effect of the essential oil (EO) obtained from the hydrodistillation of Eucalyptus globulus leaves, and an extract obtained from the hydrodistillation residual water (HRW). It was observed that EO and HRW have anti-inflammatory effect in brain immune cells modeling AD, namely lipopolysaccharide (LPS)- and amyloid-beta (Aβ)-stimulated microglia. In cell models that mimic AD-related neuronal dysfunction, HRW attenuated Aβ secretion and Aβ-induced mitochondrial dysfunction. Since the HRW's major components did not cross the blood-brain barrier, both EO and HRW were administered to the APP/PS1 transgenic AD mouse model by an intranasal route, which reduced cortical and hippocampal Aβ levels, and to rescue memory deficits and anxiety-like behaviors. Finally, HRW and EO were found to regulate cholesterol levels in aged mice after intranasal administration, suggesting that these extracts can reduce hypercholesterolemia and avoid risk for AD development. Overall, findings support a protective role of E. globulus extracts against AD‑like pathology and cognitive impairment highlighting the underlying mechanisms. These extracts obtained from underused forest biomass could be useful to develop nutraceutical supplements helpful to avoid AD risk and to prevent its progression.

Chronological Dynamics of Neuroinflammatory Responses in a High-Fat Diet Mouse Model

Obesity is known to affect various tissues and contribute to conditions such as neuroinflammation. However, the specific mechanisms and time-dependent progression of these effects across different tissues remain unclear. In this study, we monitored gene expression at intervals to examine the effects of a high-fat diet (HFD) on brain, liver, adipose, and muscle tissues in male C57/BJ mice, with a particular focus on neuroinflammation. Early inflammatory responses exhibit a progression that starts in the liver, extends to adipose tissue, and subsequently involves muscle and brain tissues. Although the brain did not show significant gene expression of inflammatory responses, mechanisms leading to neuroinflammation increased after 24 weeks, possibly through systemic chronic inflammation (SCI). Notably, mitochondrial complex I activity serves as a biomarker to indicate the inflammatory transition from the liver to adipose and other tissues caused by SCI. These similar gene expression dynamics were also observed in the hippocampus of Alzheimer's patients and in an Alzheimer's mouse model treated with a HFD. These results suggest that initially, the brain suppresses inflammatory responses, including interferon-gamma (IFN-γ), more than other tissues in response to a HFD. However, at the onset of SCI, the brain eventually exhibits inflammatory dynamics similar to those of other tissues. This underscores the significance of our findings, indicating that the early kinetics of chronic IFN-γ response and mitochondrial complex I activity inhibition serve as crucial biomarkers, emerging early in various conditions, including obesity and aging.

Shedding light on microglial dysregulation in Alzheimer's disease: exploring molecular mechanisms and therapeutic avenues

Alzheimer's disease (AD) stands out as the foremost prevalent neurodegenerative disorder, characterized by a complex etiology. Various mechanisms have been proposed to elucidate its onset, encompassing amyloid-beta (Aβ) toxicity, tau hyperphosphorylation, oxidative stress and reactive gliosis. The hallmark of AD comprises Aβ and tau aggregation. These misfolded protein aggregates trigger the activation of glial cells, primarily microglia. Microglial cells serve as a major source of inflammatory mediators and their cytotoxic activation has been implicated in various aspects of AD pathology. Activated microglia can adopt M1 or M2 phenotypes, where M1 promotes inflammation by increasing pro-inflammatory cytokines and M2 suppresses inflammation by boosting anti-inflammatory factors. Overexpressed pro-inflammatory cytokines include interleukin (IL)-1β, IL-6 and tumor necrosis factor-α (TNF-α) in adjacent brain regions. Furthermore, microglial signaling pathways dysregulated in AD are myeloid differentiation primary-response protein 88 (Myd 88), colony-stimulating factor-1 receptor (CSF1R) and dedicator of cytokinesis 2 (DOCK2), which alter the physiology. Despite numerous findings, the causative role of microglia-mediated neuroinflammation in AD remains elusive. This review concisely explores cellular and molecular mechanisms of activated microglia and their correlation with AD pathogenesis. Additionally, it highlights promising therapeutics targeting microglia modulation, currently undergoing preclinical and clinical studies, for developing effective treatment for AD.

Sirtuin Proteins and Memory: A Promising Target in Alzheimer's Disease Therapy?

Sirtuins (SIRTs), nicotine adenine dinucleotide (+)-dependent histone deacetylases, have emerged as critical regulators in many signalling pathways involved in a wide range of biological processes. Currently, seven mammalian SIRTs have been characterized and are found across a number of cellular compartments. There has been considerable interest in the role of SIRTs in the brain due to their role in a plethora of metabolic- and age-related diseases, including their involvement in learning and memory function in physiological and pathophysiological conditions. Although cognitive function declines over the course of healthy ageing, neurological disorders including Alzheimer's disease (AD) can be associated with progressive cognitive impairments. This review aimed to report and integrate recent advances in the understanding of the role of SIRTs in cognitive function and dysfunction in the context of AD. We have also reviewed the use of selective and/or natural SIRT activators as potential therapeutic agents and/or adjuvants for AD.

Physical exercise-mediated neuroprotective mechanisms in Parkinson's disease, Alzheimer's disease, and epilepsy

Research suggests that physical exercise is associated with prevention and management of chronic diseases. The influence of physical exercise on brain function and metabolism and the mechanisms involved are well documented in the literature. This review provides a comprehensive overview of the potential implications of physical exercise and the molecular benefits of exercise in Parkinson's disease, Alzheimer's disease, and epilepsy. Here, we present an overview of the effects of exercise on various aspects of metabolism and brain function. To this end, we conducted an extensive literature search of the PubMed, Web of Science, and Google Scholar databases to identify articles published in the past two decades. This review delves into key aspects including the modulation of neuroinflammation, neurotrophic factors, and synaptic plasticity. Moreover, we explored the potential role of exercise in advancing therapeutic strategies for these chronic diseases. In conclusion, the review highlights the importance of regular physical exercise as a complementary non-pharmacological treatment for individuals with neurological disorders such as Alzheimer's, Parkinson's disease, and epilepsy.

From Fundamentals to Innovation in Alzheimer's Disease: Molecular Findings and Revolutionary Therapies

Alzheimer's disease (AD) is a global health concern and the leading cause of dementia in the elderly. The prevalence of this neurodegenerative condition is projected to increase concomitantly with increased life expectancy, resulting in a significant economic burden. With very few FDA-approved disease-modifying drugs available for AD, there is an urgent need to develop new compounds capable of impeding the progression of the disease. Given the unclear etiopathogenesis of AD, this review emphasizes the underlying mechanisms of this condition. It explores not only well-studied aspects, such as the accumulation of Aβ plaques and neurofibrillary tangles, but also novel areas, including glymphatic and lymphatic pathways, microbiota and the gut-brain axis, serotoninergic and autophagy alterations, vascular dysfunction, the metal hypothesis, the olfactory pathway, and oral health. Furthermore, the potential molecular targets arising from all these mechanisms have been reviewed, along with novel promising approaches such as nanoparticle-based therapy, neural stem cell transplantation, vaccines, and CRISPR-Cas9-mediated genome editing techniques. Taking into account the overlap of these various mechanisms, individual and combination therapies emerge as the future direction in the AD strategy.

Mapping cellular stress and lipid dysregulation in Alzheimer-related progressive neurodegeneration using label-free Raman microscopy

Aβ plaques are a main feature of Alzheimer's disease, and pathological alterations especially in their microenvironment have recently come into focus. However, a holistic imaging approach unveiling these changes and their biochemical nature is still lacking. In this context, we leverage confocal Raman microscopy as unbiased tool for non-destructive, label-free differentiation of progressive biomolecular changes in the Aβ plaque microenvironment in brain tissue of a murine model of cerebral amyloidosis. By developing a detailed approach, overcoming many challenges of chemical imaging, we identify spatially-resolved molecular signatures of disease-associated structures. Specifically, our study reveals nuclear condensation, indicating cellular degeneration, and increased levels of cytochrome c, showing mitochondrial dysfunction, in the vicinity of Aβ plaques. Further, we observe severe accumulation of especially unsaturated lipids. Thus, our study contributes to a comprehensive understanding of disease progression in the Aβ plaque microenvironment, underscoring the prospective of Raman imaging in neurodegenerative disorder research.

40 Hz light preserves synaptic plasticity and mitochondrial function in Alzheimer's disease model

Alzheimer's disease (AD) is the most prevalent type of dementia. Its causes are not fully understood, but it is now known that factors like mitochondrial dysfunction, oxidative stress, and compromised ion channels contribute to its onset and progression. Flickering light therapy has shown promise in AD treatment, though its mechanisms remain unclear. In this study, we used a rat model of streptozotocin (STZ)-induced AD to evaluate the effects of 40 Hz flickering light therapy. Rats received intracerebroventricular (ICV) STZ injections, and 7 days after, they were exposed to 40 Hz flickering light for 15 min daily over seven days. Cognitive and memory functions were assessed using Morris water maze, novel object recognition, and passive avoidance tests. STZ-induced AD rats exhibited cognitive decline, elevated reactive oxygen species, amyloid beta accumulation, decreased serotonin and dopamine levels, and impaired mitochondrial function. However, light therapy prevented these effects, preserving cognitive function and synaptic plasticity. Additionally, flickering light restored mitochondrial metabolites and normalized ATP-insensitive mitochondrial calcium-sensitive potassium (mitoBKCa) channel activity, which was otherwise downregulated in AD rats. Our findings suggest that 40 Hz flickering light therapy could be a promising treatment for neurodegenerative disorders like AD by preserving synaptic and mitochondrial function.

Tau Protein and Tauopathies: Exploring Tau Protein-Protein and Microtubule Interactions, Cross-Interactions and Therapeutic Strategies

Tau, a microtubule-associated protein (MAP), is essential to maintaining neuronal stability and function in the healthy brain. However, aberrant modifications and pathological aggregations of Tau are implicated in various neurodegenerative disorders, collectively known as tauopathies. The most common Tauopathy is Alzheimer's Disease (AD) counting nowadays more than 60 million patients worldwide. This comprehensive review delves into the multifaceted realm of Tau protein, puzzling out its intricate involvement in both physiological and pathological roles. Emphasis is put on Tau Protein-Protein Interactions (PPIs), depicting its interaction with tubulin, microtubules and its cross-interaction with other proteins such as Aβ1-42, α-synuclein, and the chaperone machinery. In the realm of therapeutic strategies, an overview of diverse possibilities is presented with their relative clinical progresses. The focus is mostly addressed to Tau protein aggregation inhibitors including recent small molecules, short peptides and peptidomimetics with specific focus on compounds that showed a double anti aggregative activity on both Tau protein and Aβ amyloid peptide. This review amalgamates current knowledge on Tau protein and evolving therapeutic strategies, providing a comprehensive resource for researchers seeking to deepen their understanding of the Tau protein and for scientists involved in the development of new peptide-based anti-aggregative Tau compounds.

Activation of multifunctional DNA repair APE1/Ref-1 enzyme by the dietary phytochemical Ferulic acid protects human neuroblastoma SH-SY5Y cells against Aβ(25-35)-induced oxidative stress and inflammatory responses

Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder associated with the amyloid beta (Aβ) and tau hallmarks. The molecular insights into how neuroinflammation is initially triggered and how it affects neuronal cells are yet at the age of infancy. In this study, SH-SY5Y cells were used as a model for neurons by differentiating and were co-cultured with differentiated THP1 cells (microglia model) as well as treated with Aβ(25-35) and with antioxidant FA to study inflammatory, oxidative stress responses and their effects on co-cultured neurons. Neurons co-cultured with microglial cells showed pronounced increase in ROS levels, NOS expression, truncated N-terminal form (34 kDa) of APE1 expression and AIF's translocation in the nucleus. The pre-treatment of FA, on the other hand reversed these effects. It was further evaluated how FA/Aβ treatment altered microglial phenotype that in turn affected the neurons. Microglial cells showed M1 phenotype upon Aβ(25-35) stress, while FA induced M2 phenotype against Aβ stress, suggesting that FA alleviated Aβ induced phenotype and its associated effects in the co-cultured neurons by altering the phenotype of microglial cells and induced expression of full length (37 kDa) APE1 enzyme and inhibiting AIF's nuclear translocation, thus inhibiting apoptosis. This is the first study that revealed Aβ induced cleavage of APE1 enzyme in differentiated neurons, suggesting that APE1 may be the potential early target of Aβ that loses its function and exacerbates AD pathology. FA activated a fully functional form of APE1 against Aβ stress. The impaired function of APE1 could be the initial mechanism by which Aβ induces oxidative and inflammatory responses and dietary phytochemical FA can be a potential therapeutic strategy in managing the disease by activating APE1 that not only repairs oxidative DNA base damage but also maintains mitochondrial function and alleviates neuroinflammatory responses.

Pathogenesis, diagnostics, and therapeutics for Alzheimer's disease: Breaking the memory barrier

Alzheimer's disease (AD) is the most common cause of dementia and accounts for 60-70 % of all cases. It affects millions of people worldwide. AD poses a substantial economic burden on societies and healthcare systems. AD is a progressive neurodegenerative disorder characterized by cognitive decline, memory loss, and impaired daily functioning. As the prevalence of AD continues to increase, understanding its pathogenesis, improving diagnostic methods, and developing effective therapeutics have become paramount. This comprehensive review delves into the intricate mechanisms underlying AD, explores the current state of diagnostic techniques, and examines emerging therapeutic strategies. By revealing the complexities of AD, this review aims to contribute to the growing body of knowledge surrounding this devastating disease.

The emerging role of exercise in Alzheimer's disease: Focus on mitochondrial function

Alzheimer's disease (AD) is an age-related neurodegenerative disease characterized by memory impairment and cognitive dysfunction, which eventually leads to the disability and mortality of older adults. Although the precise mechanisms by which age promotes the development of AD remains poorly understood, mitochondrial dysfunction plays a central role in the development of AD. Currently, there is no effective treatment for this debilitating disease. It is well accepted that exercise exerts neuroprotective effects by ameliorating mitochondrial dysfunction in the neurons of AD, which involves multiple mechanisms, including mitochondrial dynamics, biogenesis, mitophagy, transport, and signal transduction. In addition, exercise promotes mitochondria communication with other organelles in AD neurons, which should receive more attentions in the future.

Oxidative stress-mediated neuroinflammation in Alzheimer's disease

Reactive oxygen species (ROS) are metabolic by-products that constitute an indispensable component of physiological processes, albeit their heightened presence may proffer substantial perils to biological entities. Such a proliferation gives rise to a gradual escalation of oxidative stress within the organism, thereby compromising mitochondrial functionality and inflicting harm upon various bodily systems, with a particular predilection for the central nervous system. In its nascent stages, it is plausible that inflammation has been a facilitator in the progression of the malady. The precise role of inflammation in Alzheimer's disease (AD) remains somewhat enigmatic, although it is conceivable that activated microglia and astrocytes might be implicated in the removal of amyloid-β (Aβ) deposits. Nonetheless, prolonged microglial activation is associated with Tau phosphorylation and Aβ aggregation. Research studies have indicated that AD brains upregulate complementary molecules, inflammatory cytokines, acute phase reacting agents, and other inflammatory mediators that may cause neurodegeneration. In this review, oxidative damage products will be discussed as potential peripheral biomarkers for AD and its early stages. The disordered excretion of pro-inflammatory cytokines, chemokines, oxygen, and nitrogen-reactive species, along with the stimulation of the complement system by glial cells, has the potential to disrupt the functionality of neuronal termini. This perturbation, in turn, culminates in compromised synaptic function, a phenomenon empirically linked to the manifestation of cognitive impairments. The management of neurodegenerative conditions in the context of dementia necessitates therapeutic interventions that specifically target the excessive production of inflammatory and oxidative agents. Furthermore, we shall deliberate upon the function of microglia and oxidative injury in the etiology of AD and the ensuing neurodegenerative processes.

Brain-wide alterations revealed by spatial transcriptomics and proteomics in COVID-19 infection

Understanding the pathophysiology of neurological symptoms observed after severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection is essential to optimizing outcomes and therapeutics. To date, small sample sizes and narrow molecular profiling have limited the generalizability of findings. In this study, we profiled multiple cortical and subcortical regions in postmortem brains of patients with coronavirus disease 2019 (COVID-19) and controls with matched pulmonary pathology (total n = 42) using spatial transcriptomics, bulk gene expression and proteomics. We observed a multi-regional antiviral response without direct active SARS-CoV2 infection. We identified dysregulation of mitochondrial and synaptic pathways in deep-layer excitatory neurons and upregulation of neuroinflammation in glia, consistent across both mRNA and protein. Remarkably, these alterations overlapped substantially with changes in age-related neurodegenerative diseases, including Parkinson's disease and Alzheimer's disease. Our work, combining multiple experimental and analytical methods, demonstrates the brain-wide impact of severe acute/subacute COVID-19, involving both cortical and subcortical regions, shedding light on potential therapeutic targets within pathways typically associated with pathological aging and neurodegeneration.

Unveiling mitochondria as central components driving cognitive decline in alzheimer's disease through cross-transcriptomic analysis of hippocampus and entorhinal cortex microarray datasets

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder characterized by symptoms such as memory loss and impaired learning. This study conducted a cross-transcriptomic analysis of AD using existing microarray datasets from the hippocampus (HC) and entorhinal cortex (EC), comparing them with age-matched non-AD controls. Both of these brain regions are critical for learning and memory processing and are vulnerable areas that exhibit abnormalities in early AD. The cross-transcriptomic analysis identified 564 significantly differentially expressed genes in HC and 479 in EC. Among these, 151 genes were significantly differentially expressed in both tissues, with functions related to synaptic vesicle clustering, synaptic vesicle exocytosis/endocytosis, mitochondrial ATP synthesis, hydrogen ion transmembrane transport, and structural constituent of cytoskeleton, suggesting a potential association between cognitive decline in AD, synaptic vesicle dynamics, dysregulation of cytoskeleton organization, and mitochondrial dysfunction. Further gene ontology analysis specific to the HC revealed the gene ontology enrichment in aerobic respiration, synaptic vesicle cycle, and oxidative phosphorylation. The enrichment analysis in CA1 of HC revealed differentiation in gene expression related to mitochondrial membrane functions involved in bioenergetics, mitochondrial electron transport, and biological processes associated with microtubule-based process, while analysis in the EC region showed enrichment in synaptic vesicle dynamics which is associated with neurotransmitter release and the regulation of postsynaptic membrane potential and synaptic transmission of GABAergic and glutamatergic synapse. Protein-protein interaction analysis highlighted central hub proteins predominantly expressed in mitochondria, involved in regulation of oxidative stress and ATP synthesis. These hub proteins interact not only within the mitochondria but also with proteins in the vesicular membrane and neuronal cytoskeleton, indicating a central role of mitochondria. This finding underscores the association between clinical symptoms and mitochondrial dysregulation of synaptic vesicle dynamics, cytoskeleton organization, and mitochondrial processes in both the HC and EC of AD. Therefore, targeting these dysregulated pathways could provide promising therapeutic targets aimed at cognitive decline and memory impairment in early AD stages.

Unveiling the multifaceted pathogenesis and therapeutic drugs of Alzheimer's disease: A comprehensive review

Alzheimer's disease (AD) is a severe neurodegenerative disorder characterized by the accumulation of β-amyloid (Aβ) plaques and tau phosphorylation-induced neurofibrillary tangles. This review comprehensively summarizes AD pathogenesis and related factors, drawing on a wealth of authoritative reports and research findings. Specifically, we delve into the intricate mechanisms underlying AD pathology, including Aβ deposition, tau protein phosphorylation, cholinergic dysfunction, neuroinflammation, mitochondrial oxidative stress, ferroptosis, imbalance in the gut microbiota, and microRNA dysregulation. We also explored the effects of these factors on the brain, including synaptic damage and cognitive impairment. Moreover, our review highlights the associations between the pathogenesis of AD and inflammatory cytokines in the peripheral blood and cerebrospinal fluid, dysbiosis of the gut microbiota, and changes in microRNA expression. Overall, we provided a systematic and illustrative overview of the pathogenesis and therapeutic drugs for AD, offering help in the prevention and treatment of this condition.

A meta-analysis of bulk RNA-seq datasets identifies potential biomarkers and repurposable therapeutics against Alzheimer's disease

Alzheimer's disease (AD) poses a major challenge due to its impact on the elderly population and the lack of effective early diagnosis and treatment options. In an effort to address this issue, a study focused on identifying potential biomarkers and therapeutic agents for AD was carried out. Using RNA-Seq data from AD patients and healthy individuals, 12 differentially expressed genes (DEGs) were identified, with 9 expressing upregulation (ISG15, HRNR, MTATP8P1, MTCO3P12, DTHD1, DCX, ST8SIA2, NNAT, and PCDH11Y) and 3 expressing downregulation (LTF, XIST, and TTR). Among them, TTR exhibited the lowest gene expression profile. Interestingly, functional analysis tied TTR to amyloid fiber formation and neutrophil degranulation through enrichment analysis. These findings suggested the potential of TTR as a diagnostic biomarker for AD. Additionally, druggability analysis revealed that the FDA-approved drug Levothyroxine might be effective against the Transthyretin protein encoded by the TTR gene. Molecular docking and dynamics simulation studies of Levothyroxine and Transthyretin suggested that this drug could be repurposed to treat AD. However, additional studies using in vitro and in vivo models are necessary before these findings can be applied in clinical applications.

Chronic stress intensify PTZ-induced seizures by triggering neuroinflammation and oxidative stress

BACKGROUND

Epilepsy is a paroxysmal abnormal hypersynchronous electrical discharge characterized by recurrent seizures. It affects more than 50 million people worldwide. Stress is the leading cause of neurodegeneration and can produce seizures that may lead to or aggravate epilepsy. Inflammation plays a vital role in epilepsy by modulating oxidative stress, and levels of neuroinflammatory cytokines including NF-κB, TNF-α, and IL-1β.

METHODS

Stress-induced changes in behavior were evaluated in mice by employing behavioral assessment tests such as an elevated plus maze, light-dark box, open field test, tail suspension test, Y-maze, novel object recognition test, and Morris water maze in pentylenetetrazole (PTZ) kindled mice. Behavioral changes in all these paradigms including seizure score, latency, and frequency showed an increase in symptoms in PTZ (35 mg/kg) induced seizures in stressed mice (RS-PTZ) as compared to PTZ, Stress, and normal animals.

RESULTS

The Enzyme-linked immunosorbent assay (ELISA) results confirmed increased in serum cortisol levels. Histological examinations showed neurodegenerative changes in the hippocampus and cortex regions. The spectrophotometric evaluation showed an increase in oxidative stress by decreasing antioxidant production i.e. reduced glutathione, glutathione -s- transferase, and catalase (CAT), and increasing oxidant levels such as maloaldehyde and nitric oxide. Immunohistochemistry results showed increased expression of NF-κB, TNF-α, and IL-1β in the cortex and hippocampus of mice brains.

CONCLUSIONS

Results from the study conclude that stress increases the likelihood of eliciting an epileptic attack by increasing the level of reactive oxygen species and neuroinflammation.

The effect of eight weeks of endurance training and MitoQ supplementation on antioxidant capacity and the expression of sestrin-2 and AMPK in cardiac tissue of aged rats

PURPOSE

The present study aimed to investigate the effects of endurance training (ET) in combination with MitoQ supplementation on antioxidant indices and the expression of sesterin-2 (SESN2) as an anti-aging factor and AMPK as an energy sensor in aged male Wistar rats.

METHODS

Twenty-eight aged Wistar rats (410 ± 15 g, 22 ± 1.5 months old) were randomly divided into four groups (n = 7): Control, ET (eight weeks endurance training on the treadmill), MitoQ (250 μ/L in drinking water), and ET + MitoQ. We measured the protein and gene expression of SESN2 and AMPK in the heart tissue by western blotting and real-time PCR, respectively. In addition, antioxidant indices, superoxide dismutase (SOD), and glutathione peroxidase (GPx) activity, and oxidant malondialdehyde (MDA) concentration in the cardiac tissue and serum were measured.

RESULTS

SESN2 and AMPK protein expression significantly increased in the MitoQ group compared to the control group (P = 0.002, P = 0.0003). MDA content in tissue and serum remained unchanged in all groups (P > 0.05). MitoQ supplementation significantly increased SOD and GPx enzyme activity in serum and cardiac tissue (P = 0.001).

CONCLUSION

Overall, ET and MitoQ alone and in combination have anti-aging effects and improve the expression of AMPK and SESN2. Additionally, ET and MitoQ lead to improved antioxidant capacity in aged rats by ameliorating the activity of antioxidant enzymes.

Mitigating Hyperglycaemic Oxidative Stress in HepG2 Cells: The Role of Carica papaya Leaf and Root Extracts in Promoting Glucose Uptake and Antioxidant Defence

Background/Objectives: Diabetes often goes undiagnosed, with 60% of people in Africa unaware of their condition. Type 2 diabetes mellitus (T2DM) is associated with insulin resistance and is treated with metformin, despite the undesirable side effects. Medicinal plants with therapeutic potential, such as Carica papaya, have shown promising anti-diabetic properties. This study explored the role of C. papaya leaf and root extracts compared to metformin in reducing hyperglycaemia-induced oxidative stress and their impact on liver function using HepG2 as a reference. Methods: The cytotoxicity was assessed through the MTT assay. At the same time, glucose uptake and metabolism (ATP and ∆Ψm) in HepG2 cells treated with C. papaya aqueous leaf and root extract were evaluated using a luminometry assay. Additionally, antioxidant properties (SOD2, GPx1, GSH, and Nrf2) were measured using qPCR and Western blot following the detection of MDA, NO, and iNOS, indicators of free radicals. Results: The MTT assay showed that C. papaya extracts did not exhibit toxicity in HepG2 cells and enhanced glucose uptake compared to the hyperglycaemic control (HGC) and metformin. The glucose levels in C. papaya-treated cells increased ATP production (p < 0.05), while the ∆Ψm was significantly increased in HGR1000-treated cells (p < 0.05). Furthermore, C. papaya leaf extract upregulated GPx1 (p < 0.05), GSH, and Nrf2 gene (p < 0.05), while SOD2 and Nrf2 proteins were reduced (p > 0.05), ultimately lowering ROS (p > 0.05). Contrarily, the root extract stimulated SOD2 (p > 0.05), GPx1 (p < 0.05), and GSH levels (p < 0.05), reducing Nrf2 gene and protein expression (p < 0.05) and resulting in high MDA levels (p < 0.05). Additionally, the extracts elevated NO levels and iNOS expression (p < 0.05), suggesting potential RNS activation. Conclusion: Taken together, the leaf extract stimulated glucose metabolism and triggered ROS production, producing a strong antioxidant response that was more effective than the root extract and metformin. However, the root extract, particularly at high concentrations, was less effective at neutralising free radicals as it did not stimulate Nrf2 production, but it did maintain elevated levels of SOD2, GSH, and GPx1 antioxidants.

System biology-based assessment of the molecular mechanism of IMPHY000797 in Parkinson's disease: a network pharmacology and in-silico evaluation

IMPHY000797 derivatives have been well known for their efficacy in various diseases. Moreover, IMPHY000797 derivatives have been found to modulate such genes involved in multiple neurological disorders. Hence, this study seeks to identify such genes and the probable molecular mechanism that could be involved in the pathogenesis of Parkinson's disease. The study utilized various biological tools such as DisGeNET, STRING, Swiss target predictor, Cytoscape, AutoDock 4.2, Schrodinger suite, ClueGo, and GUSAR. All the reported genes were obtained using DisGeNET, and further, the common genes were incorporated into the STRING to get the KEGG pathway, and all the data was converted to a protein/pathway network via Cytoscape. The clustering of the genes was performed for the gene-enriched data using two-sided hypergeometrics (p-value). The binding affinity of the IMPHY000797 was verified with the highest regulated 25 proteins via utilizing the "Monte Carlo iterated search technique" and the "Emodel and Glide score" function. Three thousand five hundred eighty-three genes were identified for Parkinson's disease and 31 genes for IMPHY000797 compound, among which 25 common genes were identified. Further, the "FOXO-signaling pathway" was identified to be a modulated pathway. Among the 25 proteins, the highest modulated genes and highest binding affinity were exhibited by SIRT3, FOXO1, and PPARGC1A with the compound IMPHY000797. Further, rat toxicity analysis provided the efficacy and safety of the compound. The study was required to identify the probable molecular mechanism, which needs more confirmation from other studies, which is still a significant hit-back.

The Dual Role of Amyloid Beta-Peptide in Oxidative Stress and Inflammation: Unveiling Their Connections in Alzheimer's Disease Etiopathology

Alzheimer's disease (AD) is a progressive neurodegenerative disease, and it is currently the seventh leading cause of death worldwide. It is characterized by the extracellular aggregation of the amyloid β-peptide (Aβ) into oligomers and fibrils that cause synaptotoxicity and neuronal death. Aβ exhibits a dual role in promoting oxidative stress and inflammation. This review aims to unravel the intricate connection between these processes and their contribution to AD progression. The review delves into oxidative stress in AD, focusing on the involvement of metals, mitochondrial dysfunction, and biomolecule oxidation. The distinct yet overlapping concept of nitro-oxidative stress is also discussed, detailing the roles of nitric oxide, mitochondrial perturbations, and their cumulative impact on Aβ production and neurotoxicity. Inflammation is examined through astroglia and microglia function, elucidating their response to Aβ and their contribution to oxidative stress within the AD brain. The blood-brain barrier and oligodendrocytes are also considered in the context of AD pathophysiology. We also review current diagnostic methodologies and emerging therapeutic strategies aimed at mitigating oxidative stress and inflammation, thereby offering potential treatments for halting or slowing AD progression. This comprehensive synthesis underscores the pivotal role of Aβ in bridging oxidative stress and inflammation, advancing our understanding of AD and informing future research and treatment paradigms.

Neuroprotective Effects of Sulforaphane in a rat model of Alzheimer's Disease induced by Aβ (1-42) peptides

The intricate nature of Alzheimer's disease (AD) has presented significant hurdles in the development of effective interventions. Sulforaphane (SFN) is of interest due to its antioxidative, anti-inflammatory, and neuroprotective properties, which could address various aspects of AD pathology. This study explores the potential of SFN in a rat model of AD induced by Aβ (1-42) peptides. AD symptoms were triggered in rats by injecting Aβ (1-42) peptides directly into their cerebral ventricles. SFN (10 mg/kg and 20 mg/kg), Trigonelline (10 mg/kg), and Pioglitazone (10 mg/kg) were administered in Aβ (1-42) treated animals. Behavioral assessments were performed using the Novel Object Recognition tests. Various biochemical parameters, such as soluble Aβ (1-42), IRS-S312, GSK-3β, TNF-α, acetylcholinesterase, nitrite levels, lipid peroxidation, and reduced glutathione activity, were quantified using ELISA kits and spectrophotometric assays. Histopathological analyses included Hematoxylin and Eosin, Crystal Violet, Congo red, and IRS-1 Immunohistochemistry staining. Quantification was performed to assess neuronal loss and Aβ plaque burden. The novelty of this study lies in its comprehensive evaluation of SFN's impact on multiple AD-related pathways at dual doses. The Novel Object Recognition test revealed that SFN, especially at higher doses, improved memory deficits induced by Aβ (1-42). Biochemically, SFN reduced hippocampal Aβ levels, IRS-S312, GSK-3β, TNF-α, and acetylcholinesterase activity, while increasing glutathione levels, all in a dose-dependent manner. Histopathological analyses further confirmed SFN's protective role against Aβ-induced neuronal damage, amyloidosis, and changes in insulin signaling. These results highlight SFN's potential as a multifaceted therapeutic agent for AD, offering a promising avenue for treatment due to its antioxidative, anti-inflammatory, and neuroprotective properties. The inclusion of combination treatments with Trigonelline and Pioglitazone alongside SFN offers insights into potential synergistic effects, which could pave the way for developing combination therapies for AD.

Nicotinamide riboside modulates the reactive species interactome, bioenergetic status and proteomic landscape in a brain-region-specific manner

Nicotinamide riboside (NR), a precursor of nicotinamide adenine dinucleotide (NAD+), has robust cognitive benefits and alleviates neuroinflammation in Alzheimer's Disease (AD) mouse models without decreasing beta-amyloid plaque pathology. Such effects may be mediated by the reactive species interactome (RSI), at the metabolome level. In this study, we employed in vitro and in vivo models of oxidative stress, aging and AD to profile the effects of NR on neuronal survival, RSI, and the whole proteome characterization of cortex and hippocampus. RSI analysis yielded a complex modulation upon NR treatment. We constructed protein co-expression networks and correlated them to NR treatment and all measured reactive species. We observed brain-area specific effects of NR on co-expressed protein modules of oxidative phosphorylation, fatty acid oxidation, and neurotransmitter regulation pathways, which correlated with RSI components. The current study contributes to the understanding of modulation of the metabolome, specifically after NR treatment in AD and how it may play disease-modifying roles.

Tau‑targeting multifunctional nanocomposite based on tannic acid-metal for near-infrared fluorescence/magnetic resonance bimodal imaging-guided combinational therapy in Alzheimer's disease

Rationale: Alzheimer's disease (AD) is hallmarked by amyloid-β (Aβ) plaques and hyperphosphorylated tau (p-tau) neurofibrillary tangles. While Aβ-centric therapies have shown promise, the complex pathology of AD requires a multifaceted therapeutic approach. The weak association between Aβ levels and cognitive decline highlights the need for alternative theranostic strategies. Currently, oxidative stress and tau hyperphosphorylation are now recognized as critical pathological events in AD. Thus, therapies that concurrently attenuate oxidative stress damage and inhibit tau pathology hold great potential for AD treatment. Methods: Herein, a multifunctional neuron-targeted nanocomposite is devised to realize dual imaging-guided AD therapy, integrating the inhibition of tau pathology and reactive oxygen species (ROS)-neutralizing biofunctions. The construction of the nanocomposite incorporates polyphenolic antioxidants tannic acid (TA)-based nanoparticles carrying manganese ions (Mn2+) and fluorescent dye IR780 iodide (IR780), coupled with a neuron-specific TPL peptide. The resulting IR780-Mn@TA-TPL nanoparticles (NPs) are comprehensively evaluated in both in vitro and in vivo AD models to assess their imaging capabilities and therapeutic efficacy. Results: The nanocomposite facilitates Mn-enhanced magnetic resonance (MR) imaging and near-infrared (NIR) fluorescence imaging. It effectively neutralizes toxic ROS and reduces tau hyperphosphorylation and aggregation. In AD rat models, the nanocomposite restores neuronal density in the hippocampus and significantly improves spatial memory. Conclusions: Such a neuron‑targeting multifunctional nanocomposite represents a potential theranostic strategy for AD, signifying a shift towards bimodal imaging-guided treatment approaches.

Sex-specific decline in prefrontal cortex mitochondrial bioenergetics in aging baboons correlates with walking speed

Mitochondria play a crucial role in brain aging due to their involvement in bioenergetics, neuroinflammation and brain steroid synthesis. Mitochondrial dysfunction is linked to age-related neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease. We investigated changes in the activities of the electron transport chain (ETC) complexes in normally aging baboon brains and determined how these changes relate to donor sex, morning cortisol levels, and walking speed. Using a novel approach, we assessed mitochondrial bioenergetics from frozen prefrontal cortex (PFC) tissues from a large cohort (60 individuals) of well-characterized aging baboons (6.6-22.8 years, approximately equivalent to 26.4-91.2 human years). Aging was associated with a decline in mitochondrial ETC complexes in the PFC, which was more pronounced when activities were normalized for citrate synthase activity, suggesting that the decline in respiration is predominantly driven by changes in the specific activity of individual complexes rather than changes in mitochondrial number. Moreover, when donor sex was used as a covariate, we found that mitochondrial respiration was preserved with age in females, whereas males showed significant loss of ETC activity with age. Males had higher activities of each individual ETC complex and greater lactate dehydrogenase activity relative to females. Circulating cortisol levels correlated only with complex II-linked respiration in males. We also observed a robust positive predictive relationship between walking speed and respiration linked to complexes I, III, and IV in males but not in females. This data reveals a previously unknown link between aging and bioenergetics across multiple tissues linking frailty and bioenergetic function. This study highlights a potential molecular mechanism for sexual dimorphism in brain resilience and suggests that in males changes in PFC bioenergetics contribute to reduced motor function with age.

From Brain to Muscle: The Role of Muscle Tissue in Neurodegenerative Disorders

Neurodegenerative diseases (NDs), like amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), and Parkinson's disease (PD), primarily affect the central nervous system, leading to progressive neuronal loss and motor and cognitive dysfunction. However, recent studies have revealed that muscle tissue also plays a significant role in these diseases. ALS is characterized by severe muscle wasting as a result of motor neuron degeneration, as well as alterations in gene expression, protein aggregation, and oxidative stress. Muscle atrophy and mitochondrial dysfunction are also observed in AD, which may exacerbate cognitive decline due to systemic metabolic dysregulation. PD patients exhibit muscle fiber atrophy, altered muscle composition, and α-synuclein aggregation within muscle cells, contributing to motor symptoms and disease progression. Systemic inflammation and impaired protein degradation pathways are common among these disorders, highlighting muscle tissue as a key player in disease progression. Understanding these muscle-related changes offers potential therapeutic avenues, such as targeting mitochondrial function, reducing inflammation, and promoting muscle regeneration with exercise and pharmacological interventions. This review emphasizes the importance of considering an integrative approach to neurodegenerative disease research, considering both central and peripheral pathological mechanisms, in order to develop more effective treatments and improve patient outcomes.

Exploring the Mechanisms and Therapeutic Approaches of Mitochondrial Dysfunction in Alzheimer's Disease: An Educational Literature Review

Alzheimer's disease (AD) presents a significant challenge to global health. It is characterized by progressive cognitive deterioration and increased rates of morbidity and mortality among older adults. Among the various pathophysiologies of AD, mitochondrial dysfunction, encompassing conditions such as increased reactive oxygen production, dysregulated calcium homeostasis, and impaired mitochondrial dynamics, plays a pivotal role. This review comprehensively investigates the mechanisms of mitochondrial dysfunction in AD, focusing on aspects such as glucose metabolism impairment, mitochondrial bioenergetics, calcium signaling, protein tau and amyloid-beta-associated synapse dysfunction, mitophagy, aging, inflammation, mitochondrial DNA, mitochondria-localized microRNAs, genetics, hormones, and the electron transport chain and Krebs cycle. While lecanemab is the only FDA-approved medication to treat AD, we explore various therapeutic modalities for mitigating mitochondrial dysfunction in AD, including antioxidant drugs, antidiabetic agents, acetylcholinesterase inhibitors (FDA-approved to manage symptoms), nutritional supplements, natural products, phenylpropanoids, vaccines, exercise, and other potential treatments.

Alzheimer's Disease Pathology and Assistive Nanotheranostic Approaches for Its Therapeutic Interventions

Alzheimer's disease (AD) still prevails and continues to increase indiscriminately throughout the 21st century, and is thus responsible for the depreciating quality of health and associated sectors. AD is a progressive neurodegenerative disorder marked by a significant amassment of beta-amyloid plaques and neurofibrillary tangles near the hippocampus, leading to the consequent loss of cognitive abilities. Conventionally, amyloid and tau hypotheses have been established as the most prominent in providing detailed insight into the disease pathogenesis and revealing the associative biomarkers intricately involved in AD progression. Nanotheranostic deliberates rational thought toward designing efficacious nanosystems and strategic endeavors for AD diagnosis and therapeutic implications. The exceeding advancements in this field enable the scientific community to envisage and conceptualize pharmacokinetic monitoring of the drug, sustained and targeted drug delivery responses, fabrication of anti-amyloid therapeutics, and enhanced accumulation of the targeted drug across the blood-brain barrier (BBB), thus giving an optimistic approach towards personalized and precision medicine. Current methods idealized on the design and bioengineering of an array of nanoparticulate systems offer higher affinity towards neurocapillary endothelial cells and the BBB. They have recently attracted intriguing attention to the early diagnostic and therapeutic measures taken to manage the progression of the disease. In this article, we tend to furnish a comprehensive outlook, the detailed mechanism of conventional AD pathogenesis, and new findings. We also summarize the shortcomings in diagnostic, prognostic, and therapeutic approaches undertaken to alleviate AD, thus providing a unique window towards nanotheranostic advancements without disregarding potential drawbacks, side effects, and safety concerns.

The Potential of Mitochondrial Therapeutics in the Treatment of Oxidative Stress and Inflammation in Aging

Mitochondria are central to cellular energy production, and their dysfunction is a major contributor to oxidative stress and chronic inflammation, pivotal factors in aging, and related diseases. With aging, mitochondrial efficiency declines, leading to an increase in ROS and persistent inflammatory responses. Therapeutic interventions targeting mitochondrial health show promise in mitigating these detrimental effects. Antioxidants such as MitoQ and MitoVitE, and supplements like coenzyme Q10 and NAD + precursors, have demonstrated potential in reducing oxidative stress. Additionally, gene therapy aimed at enhancing mitochondrial function, alongside lifestyle modifications such as regular exercise and caloric restriction can ameliorate age-related mitochondrial decline. Exercise not only boosts mitochondrial biogenesis but also improves mitophagy. Enhancing mitophagy is a key strategy to prevent the accumulation of dysfunctional mitochondria, which is crucial for cellular homeostasis and longevity. Pharmacological agents like sulforaphane, SS-31, and resveratrol indirectly promote mitochondrial biogenesis and improve cellular resistance to oxidative damage. The exploration of mitochondrial therapeutics, including emerging techniques like mitochondrial transplantation, offers significant avenues for extending health span and combating age-related diseases. However, translating these findings into clinical practice requires overcoming challenges in precisely targeting dysfunctional mitochondria and optimizing delivery mechanisms for therapeutic agents. Continued research is essential to refine these approaches and fully understand the interplay between mitochondrial dynamics and aging.

Nucleoporin 153 deficiency in adult neural stem cells defines a pathological protein-network signature and defective neurogenesis in a mouse model of AD

BACKGROUND

Reduction of adult hippocampal neurogenesis is an early critical event in Alzheimer's disease (AD), contributing to progressive memory loss and cognitive decline. Reduced levels of the nucleoporin 153 (Nup153), a key epigenetic regulator of NSC stemness, characterize the neural stem cells isolated from a mouse model of AD (3×Tg) (AD-NSCs) and determine their altered plasticity and gene expression.

METHODS

Nup153-regulated mechanisms contributing to NSC function were investigated: (1) in cultured NSCs isolated from AD and wild type (WT) mice by proteomics; (2) in vivo by lentiviral-mediated delivery of Nup153 or GFP in the hippocampus of AD and control mice analyzing neurogenesis and cognitive function; (3) in human iPSC-derived brain organoids obtained from AD patients and control subjects as a model of neurodevelopment.

RESULTS

Proteomic approach identified Nup153 interactors in WT- and AD-NSCs potentially implicated in neurogenesis regulation. Gene ontology (GO) analysis showed that Nup153-bound proteins in WT-NSCs were involved in RNA metabolism, nuclear import and epigenetic mechanisms. Nup153-bound proteins in AD-NSCs were involved in pathways of neurodegeneration, mitochondrial dysfunction, proteasomal processing and RNA degradation. Furthermore, recovery of Nup153 levels in AD-NSCs reduced the levels of oxidative stress markers and recovered proteasomal activity. Lentiviral-mediated delivery of Nup153 in the hippocampal niche of AD mice increased the proliferation of early progenitors, marked by BrdU/DCX and BrdU/PSANCAM positivity and, later, the integration of differentiating neurons in the cell granule layer (BrdU/NeuN+ cells) compared with GFP-injected AD mice. Consistently, Nup153-injected AD mice showed an improvement of cognitive performance in comparison to AD-GFP mice at 1 month after virus delivery assessed by Morris Water Maze. To validate the role of Nup153 in neurogenesis we took advantage of brain organoids derived from AD-iPSCs characterized by fewer neuroepithelial progenitor loops and reduced differentiation areas. The upregulation of Nup153 in AD organoids recovered the formation of neural-like tubes and differentiation.

CONCLUSIONS

Our data suggest that the positive effect of Nup153 on neurogenesis is based on a complex regulatory network orchestrated by Nup153 and that this protein is a valuable disease target.

Mitochondrial dysfunction in sepsis: mechanisms and therapeutic perspectives

Sepsis is a severe medical condition characterized by a systemic inflammatory response, often culminating in multiple organ dysfunction and high mortality rates. In recent years, there has been a growing recognition of the pivotal role played by mitochondrial damage in driving the progression of sepsis. Various factors contribute to mitochondrial impairment during sepsis, encompassing mechanisms such as reactive nitrogen/oxygen species generation, mitophagy inhibition, mitochondrial dynamics change, and mitochondrial membrane permeabilization. Damaged mitochondria actively participate in shaping the inflammatory milieu by triggering key signaling pathways, including those mediated by Toll-like receptors, NOD-like receptors, and cyclic GMP-AMP synthase. Consequently, there has been a surge of interest in developing therapeutic strategies targeting mitochondria to mitigate septic pathogenesis. This review aims to delve into the intricate mechanisms underpinning mitochondrial dysfunction during sepsis and its significant impact on immune dysregulation. Moreover, we spotlight promising mitochondria-targeted interventions that have demonstrated therapeutic efficacy in preclinical sepsis models.