Solving neurodegeneration: common mechanisms and strategies for new treatments

Exploring the therapeutic potential of Diosgenin as a Semaphorin-4D antagonist against neurodegenerative disorders

Neurodegenerative disorders represent a significant health challenge for the population, with their mechanisms of action being poorly understood. The development of inhibitory pharmaceuticals has encountered several obstacles, resulting in therapies that lacks the necessary efficacy. Neurodegenerative disorders are marked by a gradual deterioration of neurons, leading to a decline in various functions directed by central nervous system (CNS) including motor and non-motor symptoms. Recent focus has turned towards targeting Sema4D as a potential target for mitigating neuroinflammation and inhibiting demyelination, prevalent in various neurodegenerative disorders like Alzheimer's, Parkinson's, Huntington's, multiple sclerosis, etc. A potential answer to this is Ayurvedic phytochemicals. Phytochemicals of the Piperaceae family have been known to reverse the adversities caused by neurodegeneration. In pursuit of effective interventions, this study has conducted In-silico and In-vitro studies to evaluate the efficacy of Piper nigrum and Piper betle bioactive phytochemicals as antagonists against Sema4D. Among these, Diosgenin has emerged with notable promise, demonstrating a remarkable binding affinity of -8.84 kcal/mol with Sema4D. Molecular dynamics simulations (RMSF, RMSD, PCA, SASA, FEL, etc.) have further underscored its stability, exhibiting a consistent complex structure over 100 ns. In addition to its favourable binding properties, Diosgenin has exhibited compelling effects In-vitro. It's not only enhanced cellular viability and proliferation but also exerts protective effects against oxidative stress-induced injury in PC12 cells. These findings suggest Diosgenin's potential as a therapeutic agent against Sema4D, offering a promising avenue in the battle against neurodegenerative diseases. However, further studies are required to elucidate its precise molecular mechanisms, assess its bioavailability and toxicity in vivo, and validate its therapeutic efficacy in animal models and clinical settings.

Comprehensive evaluation of AChE inhibition by Eulophia ochreata extract utilizing in silico, ex vivo, and in vivo zebrafish models

Dementia commonly accompanies various neurodegenerative conditions, notably Alzheimer's disease. The pursuit of natural therapies for these diseases and their related symptoms has garnered widespread global interest. The present study aimed to explore the potential of Eulophia ochreata L. extract, containing phenanthrene active compounds, as an acetylcholinesterase (AChE) inhibitor. Analytical techniques confirmed the presence of phenanthrene compounds in the extract, which were then screened for AChE inhibition through molecular docking, ex vivo assays, and scopolamine-induced cognitive deficits in zebrafish larvae. These phenanthrene compounds, found in the extract of Eulophia ochreata L., exhibited a similar affinity for AChE as the standard drug Donepezil, with comparable interactions. Ex vivo assays using zebrafish larvae lysate and mouse brain homogenate indicated dose-dependent AChE inhibition with increasing extract concentrations. Behavioral assessments, including T and Y maze tests, revealed significant cognition improvement in extract-treated larvae having scopolamine-induced cognitive dysfunction, particularly at 1.3 µg/mL concentration. The combined results from molecular docking, ex vivo assays, and in vivo cognition deficit models underscored the potential of Eulophia ochreata L. extract as an AChE inhibitor, suggesting its phytochemicals could hold therapeutic promise, indicating further validation in mammalian models for translation into clinical therapies.

Potential Roles of Natural Antioxidants in Modulating Neurodegenerative Disease Pathways

Neurodegenerative diseases, including Alzheimer's, Parkinson's, and amyotrophic lateral sclerosis, are increasingly prevalent among aging populations. Oxidative stress contributes to these diseases, leading to cellular damage and neuronal death. Natural antioxidants are being explored as preventive measures. This study aims to assess the effectiveness of natural antioxidants in delaying the onset or progression of neurodegenerative diseases by identifying their specific mechanisms of action. A comprehensive review of existing literature was conducted, focusing on studies that examine the role of natural antioxidants in neuroprotection. Key natural antioxidants, including flavonoids, polyphenls, vitamins C and E, and omega-3 fatty acids, were reviewed and analyzed for their bioavailability, mechanisms of action, and outcomes in both in vitro and in vivo studies. Additionally, clinical trials involving human subjects were considered to provide insights into the translational implications of antioxidant consumption. The findings suggest that several natural antioxidants exhibit neuroprotective properties by modulating oxidative stress, reducing inflammation, and promoting neuronal survival. For instance, flavonoids such as quercetin and resveratrol have shown promise in enhancing cognitive function and mitigating the pathophysiological alterations associated with neurodegeneration. In clinical studies, higher intakes of dietary antioxidants were correlated with a reduced risk of developing neurodegenerative disorders. Natural antioxidants offer potential for preventing neurodegenerative diseases by counteracting oxidative stress and maintaining cellular integrity. Overall, our report recommends that further research is needed to optimize dosages and understand their long-term benefits.

Nanomaterial-based approaches to neurotoxin neutralization in neurodegenerative diseases

Neurodegenerative diseases (NDs) are intricately linked to the accumulation of various neurotoxins, mainly including toxic proteins, inflammatory mediators, excess metal ions, and viral pathogens. Biological neutralization strategies that use agents to competitively bind harmful substances and thus inhibit their pathogenic activity hold promise for direct removal of neurotoxins but face many limitations and challenges in NDs. Nanomaterials provide a potential solution for neurotoxin neutralization in NDs due to their unique physicochemical and biological properties. This review summarizes recent advancements in nanomaterial-based approaches to neurotoxin neutralization in NDs, highlighting the diverse design principles and mechanisms of action. We also discuss the critical role of targeted delivery to optimize neutralization efficiency and the advantages of combining different neutralization mechanisms or introducing other therapeutic components to exert the synergistic effects. Furthermore, we reveal current limitations and future research directions aimed at paving the way for nanomedicine development based on neurotoxin neutralization for the treatment of NDs.

NMR Metabolomic Profiling of Differentiated SH-SY5Y Neuronal Cells: Amyloid-β Toxicity and Protective Effects of Galantamine and Lycorine

Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder characterized by metabolic dysregulation, oxidative stress, amyloid-β (Aβ) aggregation, metal dyshomeostasis, and mitochondrial dysfunction. Current treatments provide only symptomatic relief, highlighting the need for novel therapeutic strategies. This study investigates the metabolic effects of the alkaloids galantamine (GAL) and lycorine (LYC) in differentiated SH-SY5Y neuroblastoma cells, an established in vitro model for AD, which acquire a neuronal phenotype upon differentiation. Using untargeted and targeted NMR-based metabolomics combined with multivariate statistical analysis, we analyzed extracellular metabolic profiles under basal conditions and following Aβ42 exposure, both in the presence and absence of GAL and LYC. Our findings reveal distinct metabolic responses to Aβ toxicity, with significant alterations in pyruvate and glutamine metabolism. Both GAL and LYC contributed to the restoration of glutamine and lysine homeostasis, but LYC had a more pronounced effect, better sustaining cellular energy balance and mitochondrial function. Unlike LYC, GAL treatment was associated with pyruvate accumulation, highlighting a distinct metabolic response between the two compounds. These variations may reflect distinct mechanisms of action, potentially influencing their therapeutic roles in counteracting Aβ-induced toxicity. This study highlights the value of metabolic profiling for assessing neuroprotective agents and reinforces the potential of natural alkaloids in this context.

Redox modulatory role of DJ-1 in Parkinson's disease

In particular, oxidative stress, generated by excessive reactive oxygen species (ROS), plays a major role in the neurodegenerative component of Parkinson's disease (PD) in aged neurons. DJ-1 (PARK7) is a key factor for maintaining redox homeostasis and modulation of mitochondrial function to preserve the cellular survival pathways. DJ-1 also plays a role in redox signaling independently of its antioxidant capacity by preventing the redox chain disulfide formation and stabilizing the master regulator of cellular antioxidant defense, Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2). In the DJ-1 or Nrf2 axis, expression of key antioxidant enzymes (glutathione peroxidase (GPx), superoxide dismutase (SOD), and heme oxygenase-1 (HO-1) in response to oxidative stress is increased, and decreased neuronal damage resulting from oxidative stress is achieved. It has been demonstrated that DJ-1 functions as an oxidative stress sensor, and mutations like L166P cause loss of antioxidant activity and increased Reactive Oxygen Species (ROS) accumulation with subsequent mitochondrial dysfunction in dopaminergic neurons. The highly conserved cysteine residue at position 106 (Cys106) of DJ-1 becomes stepwise oxidized (Cys-SOH → Cys-SO₂H → Cys-SO3H), functioning as a redox sensor as well as redox modulator of cellular stress responses. Furthermore, by protecting against α-synuclein aggregation, DJ-1 also protects in models lacking DJ-1, whereby DJ-1 deficiency promotes protein misfolding and neurotoxicity. In addition, DJ-1 participates in regulating neuroinflammation since its diminution provokes NF-κB-mediated exacerbation of proinflammatory cytokine production, leading to neuronal death. Oxidized DJ-1 (OxiDJ-1) is generated in aging brains, particularly in the substantia nigra (SN), and is correlated with PD progression both as a biomarker for disease monitoring and diagnosis of PD early in its course. The therapeutic strategies aimed at DJ-1 include small molecular activators, protein supplementation (Tat-DJ-1, ND-13), and gene therapy aiming to restore the neuroprotective function of DJ-1. Since DJ-1 is multitasking to protect neurons from oxidative damage, mitochondrial dysfunction, and even inflammation, it remains a promising therapeutic target. This review highlights the molecular mechanisms through which DJ-1 can protect from PD and aging-related neurodegeneration and has potential utility as a biomarker or therapeutic target.

Biomarkers in glioblastoma and degenerative CNS diseases: defining new advances in clinical usefulness and therapeutic molecular target

Background

Discovering biomarkers is central to the research and treatment of degenerative central nervous system (CNS) diseases, playing a crucial role in early diagnosis, disease monitoring, and the development of new treatments, particularly for challenging conditions like degenerative CNS diseases and glioblastoma (GBM).

Methods

This study analyzed gene expression data from a public database, employing differential expression analyses and Gene Co-expression Network Analysis (WGCNA) to identify gene modules associated with degenerative CNS diseases and GBM. Machine learning methods, including Random Forest, Least Absolute Shrinkage and Selection Operator (LASSO), and Support Vector Machine - Recursive Feature Elimination (SVM-RFE), were used for case-control differentiation, complemented by functional enrichment analysis and external validation of key genes.

Results

Ninety-five commonly altered genes related to degenerative CNS diseases and GBM were identified, with RELN and GSTO2 emerging as significant through machine learning screening. Receiver operating characteristic (ROC) analysis confirmed their diagnostic value, which was further validated externally, indicating their elevated expression in controls.

Conclusion

The study's integration of WGCNA and machine learning uncovered RELN and GSTO2 as potential biomarkers for degenerative CNS diseases and GBM, suggesting their utility in diagnostics and as therapeutic targets. This contributes new perspectives on the pathogenesis and treatment of these complex conditions.

A Sensor-Based Classification for Neuromotor Robot-Assisted Rehabilitation

Neurological diseases leading to motor deficits constitute significant challenges to healthcare systems. Despite technological advancements in data acquisition, sensor development, data processing, and virtual reality (VR), a suitable framework for patient-centered neuromotor robot-assisted rehabilitation using collective sensor information does not exist. An extensive literature review was achieved based on 124 scientific publications regarding different types of sensors and the usage of the bio-signals they measure for neuromotor robot-assisted rehabilitation. A comprehensive classification of sensors was proposed, distinguishing between specific and non-specific parameters. The classification criteria address essential factors such as the type of sensors, the data they measure, their usability, ergonomics, and their overall impact on personalized treatment. In addition, a framework designed to collect and utilize relevant data for the optimal rehabilitation process efficiently is proposed. The proposed classifications aim to identify a set of key variables that can be used as a building block for a dynamic framework tailored for personalized treatments, thereby enhancing the effectiveness of patient-centered procedures in rehabilitation.

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.

Unlocking Hope: Therapeutic Advances and Approaches in Modulating the Wnt Pathway for Neurodegenerative Diseases

Neurodegenerative diseases (NDs) are conditions characterized by sensory, motor, and cognitive impairments due to alterations in the structure and function of neurons in the central nervous system (CNS). Despite their widespread occurrence, the exact causes of NDs remain largely elusive, and existing treatments fall short in efficacy. The Wnt signaling pathway is an emerging molecular pathway that has been linked to the development and progression of various NDs. Wnt signaling governs numerous cellular processes, such as survival, polarity, proliferation, differentiation, migration, and fate specification, via a complex network of proteins. In the adult CNS, Wnt signaling regulates synaptic transmission, plasticity, memory formation, neurogenesis, neuroprotection, and neuroinflammation, all essential for maintaining neuronal function and integrity. Dysregulation of both canonical and non-canonical Wnt signaling pathways contributes to neurodegeneration through various mechanisms, such as amyloid-β accumulation, tau protein hyperphosphorylation, dopaminergic neuron degeneration, and synaptic dysfunction, prompting investigations into Wnt modulation as a therapeutic target to restore neuronal function and prevent or delay neurodegenerative processes. Modulating Wnt signaling has the potential to restore neuronal function and impede or postpone neurodegenerative processes, offering a therapeutic approach for targeting NDs. In this article, the current knowledge about how Wnt signaling works in Alzheimer's disease and Parkinson's disease is discussed. Our study aims to explore the molecular mechanisms, recent discoveries, and challenges involved in developing Wnt-based therapies.

Decoding and reconstructing disease relations between dry eye and depression: a multimodal investigation comprising meta-analysis, genetic pathways and Mendelian randomization

INTRODUCTION

The clinical presentations of dry eye disease (DED) and depression (DEP) often comanifest. However, the robustness and the mechanisms underlying this association were undetermined.

OBJECTIVES

To this end, we set up a three-segment study that employed multimodality results (meta-analysis, genome-wide association study [GWAS] and Mendelian randomization [MR]) to elucidate the association, common pathways and causality between DED and DEP.

METHODS

A meta-analysis comprising 26 case-control studies was first conducted to confirm the DED-DEP association. Next, we performed a linkage disequilibrium (LD)-adjusted GWAS and targeted phenotype association study (PheWAS) in East Asian TW Biobank (TWB) and European UK Biobank (UKB) populations. Single-nucleotide polymorphisms (SNPs) were further screened for molecular interactions and common pathways at the functional gene level. To further elucidate the activated pathways in DED and DEP, a systemic transcriptome review was conducted on RNA sequencing samples from the Gene Expression Omnibus. Finally, 48 MR experiments were implemented to examine the bidirectional causation between DED and DEP.

RESULTS

Our meta-analysis showed that DED patients are associated with an increased DEP prevalence (OR = 1.83), while DEP patients have a concurrent higher risk of DED (OR = 2.34). Notably, cross-disease GWAS analysis revealed that similar genetic architecture (rG = 0.19) and pleiotropic functional genes contributed to phenotypes in both diseases. Through protein-protein interaction and ontology convergence, we summarized the pleiotropic functional genes under the ontology of immune activation, which was further validated by a transcriptome systemic review. Importantly, the inverse variance-weighted (IVW)-MR experiments in both TWB and UKB populations (p value <0.001) supported the bidirectional exposure-outcome causation for DED-to-DEP and DEP-to-DED. Despite stringent LD-corrected instrumental variable re-selection, the bidirectional causation between DED and DEP remained.

CONCLUSION

With the multi-modal evidence combined, we consolidated the association and causation between DED and DEP.

Nalidixic acid inhibits the aggregation of HSA: Utilizing the molecular simulations to uncover the detailed insights

Neurodegenerative diseases such as Parkinson's and Alzheimer's lead to the gradual decline of the nervous system, resulting in cognitive and motor impairments. With an aging population, the prevalence and associated healthcare costs are anticipated to rise. Misfolded protein aggregates are central to these diseases, disrupting cellular function and causing neuronal death. Preventing these toxic aggregates could preserve neurons and slow disease progression. Understanding how to inhibit protein aggregation is crucial for developing effective treatments. We explored the effect of nalidixic acid (NA) on protein aggregation using human serum albumin (HSA) as model protein. In vitro assays demonstrated that NA significantly reduced ThT fluorescence by 47.10 % and decreased turbidity by 63.07 %. NA also protected the protein's hydrophobic surfaces. The α-helical content of HSA dropped from 56.23 % to 11.43 % but was restored to 38.53 % with NA. We then utilized advanced molecular simulations to understand the kinetics and mechanism of aggregation inhibition by NA. Binding studies showed that NA attaches to HSA's subdomain IIA with a binding energy of -7.8 kcal/mol through hydrogen bonds, Van der Waals forces, and hydrophobic interactions. Molecular simulations confirmed the stability of HSA-NA complex. Additionally, NA increased solvent accessibility of HSA282-292 oligomers, reduced hydrogen bonding, and prevented β-sheet formation. Compared to existing anti-aggregation strategies, NA offers a promising alternative with its potential therapeutic applications in neurodegenerative diseases by stabilizing protein structures and preventing misfolding. These findings highlight NA's potential as a candidate for inhibiting protein aggregation and offer insights for therapeutic approaches. Further experimental studies utilizing in vivo models are needed to validate the anti-aggregation potential of NA.

Multi-targeted benzylpiperidine-isatin hybrids: Design, synthesis, biological and in silico evaluation as monoamine oxidases and acetylcholinesterase inhibitors for neurodegenerative disease therapies

Neurodegenerative diseases (NDDs) like Alzheimer's and Parkinson's, characterized by gradual loss of neuronal structure and function, results in cognitive and motor impairments. These complex disorders involve multiple pathogenic mechanisms, including neurotransmitter imbalances, oxidative stress, and protein misfolding, necessitating multifunctional therapeutic approaches. Piperidine and isatin are valuable scaffolds in drug design due to their favorable pharmacokinetic profiles, ability to cross blood-brain barrier, and ease of modification. This study focuses on design, synthesis, and evaluation of benzylpiperidine-isatin hybrids as dual inhibitors targeting key enzymes implicated in NDDs: monoamine oxidases (MAO-A/B) and acetylcholinesterase (AChE). Strategic hybridization of piperidine and isatin produced novel benzylpiperidine-isatin hybrids, combining pharmacological benefits of both scaffolds. Synthesized hybrids were tested for MAO-A/B and AChE inhibitory effects. 15 emerged as a lead inhibitor for both MAO-A (IC50 = 0.108 ± 0.004 μM, competitive and reversible) and AChE (IC50 = 0.034 ± 0.002 μM, mixed and reversible), outperforming donepezil in AChE inhibition. 4 showed significant MAO-B inhibition (IC50 = 0.057 ± 0.001 μM, competitive and reversible). SAR studies identified crucial structural elements for potency and selectivity, while molecular docking revealed key interactions stabilizing the enzyme-inhibitor complexes. MD simulations of lead molecules demonstrate the ligand's suitability for strong and consistent binding to the respective proteins. Lead compounds were non-neurotoxic, exhibited good antioxidant properties, and had favorable in silico ADMET predictions. These findings suggest that benzylpiperidine-isatin hybrids hold promise as multifunctional agents against NDDs, warranting further refinement to enhance their efficacy and safety.

Association between apical periodontitis and brain inflammation: a systematic review from animals and human studies

Apical periodontitis (AP) is an oral inflammatory disease induced by dental pulp infection. It is characterized by inflammation, destruction, and resorption of mineralized tissues located around the dental apex. Although this is a local infection, pathogens and their products in the periapical area, as well as inflammatory cytokines, can reach other regions of the body and trigger a systemic immune/inflammatory response in the host. This condition has been associated with several types of systemic diseases. This systematic review aimed to explore the association between AP and neuroinflammation, providing insights into this relationship and discussing potential pathways used by AP microorganisms to reach the central nervous system. Extensive searches in electronic databases (PubMed, Embase, and Cochrane) and hand searches were conducted from January 2013 until May 2024, using the keywords apical periodontitis, endodontic infection, periapical abscess, periodontitis apical, brain inflammation, brain disorders, and neuroinflammation. Initially, 394 studies were selected. After exclusion and inclusion criteria were applied, 12 studies (7 case reports and 1 case series, 3 experimental studies using animal models, and 1 cohort study) were included in this systematic review. All studies showed the presence of AP in upper and/or lower teeth and brain disorders with neuroinflammation. It is important to mention that some cases reported the death of the patient. This systematic review indicates a significant relationship between AP and neuroinflammation based on animal and human studies. Moreover, this study suggests there may be pathways connecting upper and lower teeth with apical periodontitis to the brain, inducing neuroinflammation. Additionally, the oral cavity can become easily accessible when AP is present, allowing for the invasion of microorganisms that are usually non-invasive. This contributes to the development of systemic disorders and/or strengthens their effect, worsening brain pathologies by causing or enhancing neuroinflammation, potentially leading to death. Based on these inferences, periapex health care is essential to improve the health of the world population.Registration number: Prospero registration nº. CRD42023453543.

Therapeutic Potential of Arimoclomol Nanomicelles: In Vitro Impact on Alzheimer's and Parkinson's Pathology and Correlation with In Vivo Inflammatory Response

This study investigates the potential of arimoclomol-loaded nanomicelles for the treatment of neurodegenerative diseases like Alzheimer's and Parkinson's, as well as their anti-inflammatory properties. Arimoclomol, a coinducer of heat shock proteins (HSPs), has shown clinical promise in mitigating protein misfolding, a hallmark of these diseases. In this work, arimoclomol nanomicelles significantly reduced the aggregation of β-amyloid (Aβ1-42) and α-synuclein (α-syn), key pathological proteins in Alzheimer's and Parkinson's. Additionally, the nanomicelles demonstrated potent anti-inflammatory effects, reducing leukocyte and neutrophil counts in an acute inflammation model. These results suggest that arimoclomol nanomicelles could enhance clinical outcomes by targeting both neurodegenerative and inflammatory processes, offering a promising therapeutic strategy for long-term disease management.

Application of Network Pharmacology in the Treatment of Neurodegenerative Diseases with Traditional Chinese Medicine

In recent years, the incidence of neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, has exhibited a steadily rising trend, which has posed a major challenge to the global public health. Traditional Chinese medicine, with its multicomponent and multitarget characteristics, offers a promising approach to treating neurodegenerative diseases. However, comprehensively elucidating the complex mechanisms underlying traditional Chinese medicine formulations remains challenging. As an emerging systems biology method, network pharmacology has provided a vital tool for revealing the multitarget mechanisms of traditional Chinese medicine through high-throughput technologies, molecular docking, and network analysis. This paper reviews the advancements in the application of network pharmacology in treating neurodegenerative diseases using traditional Chinese medicine, analyzes the current status of relevant databases and technological methods, discusses the limitations, and proposes future directions to promote the modernization of traditional Chinese medicine and the development of precision medicine.

"Nattokinase as a potential therapeutic agent for preventing blood-brain barrier dysfunction in neurodegenerative disorders"

Neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis are characterized by progressive destruction of neurons and cognitive impairment, and thorough studies have provided evidence that these pathologies have a close relationship to the failure of the blood-brain barrier (BBB). Nattokinase (NK), a protease found in fermented soybeans, has been extensively studied because it displays powerful neuroprotective abilities, which is why current research was reviewed in the present article. It was concluded that there is enough evidence in preclinical studies using experimental animals that NK supplementation can alleviate the condition related to BBB dysfunction, reduce brain inflammation, and improve cognitive ability. Furthermore, the study of NK on the cardiovascular system leads to certain assumptions, which include the impact on vasculature function and the ability to manage blood flow, which is the key feature of BBB integrity. Such assumed mechanisms are fibrinolytic action, anti-inflammatory and antioxidant action, and endothelium function modulation. There are many positive research findings, and it seems that NK may serve as an effective opponent for BBB breakdown; however, a new research level should be taken to disclose the application and therapeutic use of NK in brain neurodegenerative disease.

Plant-derived compounds and neurodegenerative diseases: Different mechanisms of action with therapeutic potential

Neurodegenerative diseases are a group of disorders characterized by progressive degeneration of discrete groups of neurons causing severe disability. The main risk factor is age, hence their incidence is rapidly increasing worldwide due to the rise in life expectancy. Although the causes of the disease are not identified in about 90% of the cases, in the last decades there has been great progress in understanding the basis for neurodegeneration. Different pathological mechanisms including oxidative stress, mitochondrial dysfunction, alteration in proteostasis and inflammation have been addressed as important contributors to neuronal death. Despite our better understanding of the pathophysiology of these diseases, there is still no cure and available therapies only provide symptomatic relief. In an effort to discover new therapeutic approaches, natural products have aroused interest among researchers given their structural diversity and wide range of biological activities. In this review, we focus on three plant-derived compounds with promising neuroprotective potential that have been traditionally used by folk medicine: the flavonoid quercetin (QCT), the phytocannabinoid cannabidiol (CBD)and the tryptamine N,N-dimethyltryptamine (DMT). These compounds exert neuroprotective effects through different mechanisms of action, some overlapping, but each demonstrating a principal biological activity: QCT as an antioxidant, CBD as an anti-inflammatory, and DMT as a promoter of neuroplasticity. This review summarizes current knowledge on these activities, potential therapeutic benefits of these compounds and their limitations as candidates for neuroprotective therapies. We envision that treatments with QCT, CBD, and DMT could be effective either when combined or when targeting different stages of these diseases.

Molecular biomarkers of glial activation and injury in epilepsy

Increasing evidence from fluid biopsies suggests activation and injury of glial cells in epilepsy. The prevalence of clinical and subclinical seizures in neurodegenerative conditions such as Alzheimer's disease, frontotemporal dementia, and others merits review and comparison of the effects of seizures on glial markers in epilepsy and neurodegenerative diseases with concomitant seizures. Herein, we revisit preclinical and clinical reports of alterations in glial proteins in cerebrospinal fluid and blood associated with various types of epilepsy. We consider shared and distinct characteristics of changes in different age groups and sexes, in humans and animal models of epilepsy, and compare them with those reported in biofluids in neurodegenerative diseases. Our analysis indicates a significant overlap of glial response in these prevalent neurological conditions.

Stress-induced mitochondrial fragmentation in endothelial cells disrupts blood-retinal barrier integrity causing neurodegeneration

Increased vascular leakage and endothelial cell (EC) dysfunction are major features of neurodegenerative diseases. Here, we investigated the mechanisms leading to EC dysregulation and asked whether altered mitochondrial dynamics in ECs impinge on vascular barrier integrity and neurodegeneration. We show that ocular hypertension, a major risk factor to develop glaucoma, induced mitochondrial fragmentation in retinal capillary ECs accompanied by increased oxidative stress and ultrastructural defects. Analysis of EC mitochondrial components revealed overactivation of dynamin-related protein 1 (DRP1), a central regulator of mitochondrial fission, during glaucomatous damage. Pharmacological inhibition or EC-specific in vivo gene delivery of a dominant negative DRP1 mutant was sufficient to rescue mitochondrial volume, reduce vascular leakage, and increase expression of the tight junction claudin-5 (CLDN5). We further demonstrate that EC-targeted CLDN5 gene augmentation restored blood-retinal-barrier integrity, promoted neuronal survival, and improved light-evoked visual behaviors in glaucomatous mice. Our findings reveal that preserving mitochondrial homeostasis and EC function are valuable strategies to enhance neuroprotection and improve vision in glaucoma.

Circadian Rhythms and Lung Cancer in the Context of Aging: A Review of Current Evidence

Circadian rhythm is the internal homeostatic physiological clock that regulates the 24-hour sleep/wake cycle. This biological clock helps to adapt to environmental changes such as light, dark, temperature, and behaviors. Aging, on the other hand, is a process of physiological changes that results in a progressive decline in cells, tissues, and other vital systems of the body. Both aging and the circadian clock are highly interlinked phenomena with a bidirectional relationship. The process of aging leads to circadian disruptions while dysfunctional circadian rhythms promote age-related complications. Both processes involve diverse physiological, molecular, and cellular changes such as modifications in the DNA repair mechanisms, mechanisms, ROS generation, apoptosis, and cell proliferation. This review aims to examine the role of aging and circadian rhythms in the context of lung cancer. This will also review the existing literature on the role of circadian disruptions in the process of aging and vice versa. Various molecular pathways and genes such as BMAL1, SIRT1, HLF, and PER1 and their implications in aging, circadian rhythms, and lung cancer will also be discussed.

Phytosome-Encapsulated 6-Gingerol- and 6-Shogaol-Enriched Extracts from Zingiber officinale Roscoe Protect Against Oxidative Stress-Induced Neurotoxicity

The rising prevalence of neurodegenerative disorders underscores the urgent need for effective interventions to prevent neuronal cell death. This study evaluates the neuroprotective potential of phytosome-encapsulated 6-gingerol- and 6-shogaol-enriched extracts from Zingiber officinale Roscoe (6GS), bioactive compounds renowned for their antioxidant and anti-inflammatory properties. The novel phytosome encapsulation technology employed enhances the bioavailability and stability of these compounds, offering superior therapeutic potential compared to conventional formulations. Additionally, the study investigates the role of the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)-signaling pathway, a key mediator of the neuroprotective effects of 6GS. Neurotoxicity was induced in SH-SY5Y cells (a human neuroblastoma cell line) using 200 μM of hydrogen peroxide (H2O2), following pretreatment with 6GS at concentrations of 15.625 and 31.25 μg/mL. Cell viability was assessed via the MTT assay alongside evaluations of reactive oxygen species (ROS), antioxidant enzyme activities (superoxide dismutase [SOD], catalase [CAT], glutathione peroxidase [GSH-Px]), oxidative stress markers (malondialdehyde [MDA]), and molecular mechanisms involving the PI3K/Akt pathway, apoptotic factors (B-cell lymphoma-2 [Bcl-2] and caspase-3), and inflammatory markers (tumor necrosis factor-alpha [TNF-α]). The results demonstrated that 6GS significantly improved cell viability, reduced ROS, MDA, TNF-α, and caspase-3 levels, and enhanced antioxidant enzyme activities. Furthermore, 6GS treatment upregulated PI3K, Akt, and Bcl-2 expression while suppressing caspase-3 activation. Activation of the PI3K/Akt pathway by 6GS led to phosphorylated Akt-mediated upregulation of Bcl-2, promoting neuronal survival and attenuating oxidative stress and inflammation. Moreover, Bcl-2 inhibited ROS generation, further mitigating neurotoxicity. These findings suggest that phytosome encapsulation enhances the bioavailability of 6GS, which through activation of the PI3K/Akt pathway, exhibits significant neuroprotective properties. Incorporating these compounds into functional foods or dietary supplements could offer a promising strategy for addressing oxidative stress and neuroinflammation associated with neurodegenerative diseases.

Endoplasmic reticulum stress-related deficits in calcium clearance promote neuronal dysfunction that is prevented by SERCA2 gene augmentation

Disruption of calcium (Ca2+) homeostasis in neurons is a hallmark of neurodegenerative diseases. Here, we investigate the mechanisms leading to Ca2+ dysregulation and ask whether altered Ca2+ dynamics impinge on neuronal stress and circuit dysfunction. Using two-photon microscopy, we show that ocular hypertension, a major risk factor in glaucoma, and optic nerve crush injury disrupt the capacity of retinal neurons to clear cytosolic Ca2+ leading to impaired light-evoked responses. Gene- and protein expression analysis reveal the loss of the sarco-endoplasmic reticulum (ER) Ca2+-ATPase2 pump (SERCA2/ATP2A2) in injured retinal neurons from mice and patients with primary open-angle glaucoma. Pharmacological activation or neuron-specific gene delivery of SERCA2 is sufficient to rescue single-cell Ca2+ dynamics and promote robust survival of damaged neurons. Furthermore, SERCA2 gene supplementation reduces ER stress, reestablishes circuit balance, and restores visual behaviors. Our findings reveal that enhancing the Ca2+ clearance capacity of vulnerable neurons alleviates organelle stress and promotes neurorecovery.

Perspectives of traditional herbal medicines in treating retinitis pigmentosa

Medicinal plants, also known as herbs, have been discovered and utilized in traditional medical practice since prehistoric times. Medicinal plants have been proven rich in thousands of natural products that hold great potential for the development of new drugs. Previously, we reviewed the types of Chinese traditional medicines that a Tang Dynasty monk Jianzhen (Japanese: Ganjin) brought to Japan from China in 742. This article aims to review the origin of Kampo (Japanese traditional medicine), and to present the overview of neurodegenerative diseases and retinitis pigmentosa as well as medicinal plants in some depth. Through the study of medical history of the origin of Kampo, we found that herbs medicines contain many neuroprotective ingredients. It provides us a new perspective on extracting neuroprotective components from herbs medicines to treat neurodegenerative diseases. Retinitis pigmentosa (one of the ophthalmic neurodegenerative diseases) is an incurable blinding disease and has become a popular research direction in global ophthalmology. To date, treatments for retinitis pigmentosa are very limited worldwide. Therefore, we intend to integrate the knowledge and skills from different disciplines, such as medical science, pharmaceutical science and plant science, to take a new therapeutic approach to treat neurodegenerative diseases. In the future, we will use specific active ingredients extracted from medicinal plants to treat retinitis pigmentosa. By exploring the potent bioactive ingredients present in medicinal plants, a valuable opportunity will be offered to uncover novel approaches for the development of drugs which target for retinitis pigmentosa.

Neuroimaging techniques, gene therapy, and gut microbiota: frontier advances and integrated applications in Alzheimer's Disease research

Alzheimer's Disease (AD) is a neurodegenerative disorder marked by cognitive decline, for which effective treatments remain elusive due to complex pathogenesis. Recent advances in neuroimaging, gene therapy, and gut microbiota research offer new insights and potential intervention strategies. Neuroimaging enables early detection and staging of AD through visualization of biomarkers, aiding diagnosis and tracking of disease progression. Gene therapy presents a promising approach for modifying AD-related genetic expressions, targeting amyloid and tau pathology, and potentially repairing neuronal damage. Furthermore, emerging evidence suggests that the gut microbiota influences AD pathology through the gut-brain axis, impacting inflammation, immune response, and amyloid metabolism. However, each of these technologies faces significant challenges, including concerns about safety, efficacy, and ethical considerations. This article reviews the applications, advantages, and limitations of neuroimaging, gene therapy, and gut microbiota research in AD, with a particular focus on their combined potential for early diagnosis, mechanistic insights, and therapeutic interventions. We propose an integrated approach that leverages these tools to provide a multi-dimensional framework for advancing AD diagnosis, treatment, and prevention.

Microencapsulation and nanoencapsulation of bacterial probiotics: new frontiers in Alzheimer's disease treatment

Alzheimer's disease, a progressive neurodegenerative disorder marked by cognitive decline, affects millions worldwide. The presence of amyloid plaques and neurofibrillary tangles in the brain is the key pathological feature, leading to neuronal dysfunction and cell death. Current treatment options include pharmacological approaches such as cholinesterase inhibitors, as well as non-pharmacological strategies like cognitive training and lifestyle modifications. Recently, the potential role of probiotics, particularly strains, such as Lactobacillus and Bifidobacterium, in managing neurodegenerative diseases through the gut-brain axis has garnered significant attention. Probiotics can modulate inflammation, produce neurotransmitters, and support neuronal health, potentially slowing disease progression and alleviating symptoms, such as stress and anxiety. Optimizing the pharmacotherapeutic effects of probiotics is critical and involves advanced formulation techniques, such as microencapsulation and nanoencapsulation. Microencapsulation employs natural or synthetic polymers to protect probiotic cells, enhancing their viability and stability against environmental stressors. Methods like extrusion, emulsion, and spray-drying are used to create microcapsules suited for various applications. Nanoencapsulation, on the other hand, operates at the nanoscale, utilizing polymeric or lipid-based nanoparticles to improve the bioavailability and shelf life of probiotics. Techniques, such as nanoprecipitation and emulsification, are employed to ensure stable nanocapsule formation, thereby augmenting the therapeutic potential of probiotics as nutraceutical agents. This study delves into the essential formulation aspects of microencapsulation and nanoencapsulation for beneficial probiotic strains, aimed at managing Alzheimer's disease by optimizing the gut-brain axis. The insights gained from these advanced techniques promise to enhance probiotic delivery efficacy, potentially leading to improved health outcomes for patients suffering from neurodegenerative disorders.

Regulation of disease-associated microglia in the optic nerve by lipoxin B4 and ocular hypertension

BACKGROUND

The resident astrocyte-retinal ganglion cell (RGC) lipoxin circuit is impaired during retinal stress, which includes ocular hypertension-induced neuropathy. Lipoxin B4 produced by homeostatic astrocytes directly acts on RGCs to increase survival and function in ocular hypertension-induced neuropathy. RGC death in the retina and axonal degeneration in the optic nerve are driven by the complex interactions between microglia and macroglia. Whether LXB4 neuroprotective actions include regulation of other cell types in the retina and/or optic nerve is an important knowledge gap.

METHODS

Cellular targets and signaling of LXB4 in the retina were defined by single-cell RNA sequencing. Retinal neurodegeneration was induced by injecting silicone oil into the anterior chamber of mouse eyes, which induced sustained and stable ocular hypertension. Morphological characterization of microglia populations in the retina and optic nerve was established by MorphOMICs and pseudotime trajectory analyses. The pathways and mechanisms of action of LXB4 in the optic nerve were investigated using bulk RNA sequencing. Transcriptomics data was validated by qPCR and immunohistochemistry. Differences between experimental groups were assessed by Student's t-test and one-way ANOVA.

RESULTS

Single-cell transcriptomics identified microglia as a primary target for LXB4 in the healthy retina. LXB4 downregulated genes that drive microglia environmental sensing and reactivity responses. Analysis of microglial function revealed that ocular hypertension induced distinct, temporally defined, and dynamic phenotypes in the retina and, unexpectedly, in the distal myelinated optic nerve. Microglial expression of CD74, a marker of disease-associated microglia in the brain, was only induced in a unique population of optic nerve microglia, but not in the retina. Genetic deletion of lipoxin formation correlated with the presence of a CD74 optic nerve microglia population in normotensive eyes, while LXB4 treatment during ocular hypertension shifted optic nerve microglia toward a homeostatic morphology and non-reactive state and downregulated the expression of CD74. Furthermore, we identified a correlation between CD74 and phospho-phosphoinositide 3-kinases (p-PI3K) expression levels in the optic nerve, which was reduced by LXB4 treatment.

CONCLUSION

We identified early and dynamic changes in the microglia functional phenotype, reactivity, and induction of a unique CD74 microglia population in the distal optic nerve as key features of ocular hypertension-induced neurodegeneration. Our findings establish microglia regulation as a novel LXB4 target in the retina and optic nerve. LXB4 maintenance of a homeostatic optic nerve microglia phenotype and inhibition of a disease-associated phenotype are potential neuroprotective mechanisms for the resident LXB4 pathway.

Associations of human blood metabolome with optic neurodegenerative diseases: a bi-directionally systematic mendelian randomization study

BACKGROUND

Metabolic disruptions were observed in patients with optic neurodegenerative diseases (OND). However, evidence for the causal association between metabolites and OND is limited.

METHODS

Two-sample Mendelian randomization (MR). Summary data for 128 blood metabolites was selected from three genome-wide association study (GWASs) involving 147,827 participants of European descent. GWASs Data for glaucoma (20906 cases and 391275 controls) and age-related macular degeneration (AMD, 9721 cases and 381339 controls) came from FinnGen consortium. A bi-directional MR was conducted to assess causality, and a Mediation MR was further applied to explore the indirect effect, a phenome-wide MR analysis was then performed to identify possible side-effects of the therapies.

RESULTS

All the results underwent correction for multiple testing and rigorous sensitivity analyses. We identified N-acetyl glycine, serine, uridine were linked to an elevated risk of glaucoma. 1-arachidonic-glycerol-phosphate-ethanolamine, 4-acetamido butanoate, o-methylascorbate, saturated fatty acids, monounsaturated fatty acids, VLDL cholesterol, serum total cholesterol, X-11,529 were linked to reduced risk of glaucoma. There were 4 metabolites linked to a reduced risk of AMD, including tryptophan betaine, 4-androsten-3beta-17beta-diol disulfate, apolipoprotein B, VLDL cholesterol. We discovered IOP, AS, T2D as glaucoma risk factors, while BMI, AS, GCIPL as AMD factors. And 6 metabolites showed associations with risk factors in the same direction as their associations with glaucoma/AMD. Phenome-wide MR indicated that selected metabolites had protective/adverse effects on other diseases.

CONCLUSIONS

By integrating genomics and metabolomics, this study supports new insights into the intricate mechanisms, and helps prevent and screen glaucoma and AMD.

Müller Glial Cell-Dependent Regeneration of the Retina in Zebrafish and Mice

Sight is one of our most precious senses. People fear losing their sight more than any other disability. Thus, restoring sight to the blind is an important goal of vision scientists. Proregenerative species, such as zebrafish, provide a system for studying endogenous mechanisms underlying retina regeneration. Nonregenerative species, such as mice, provide a system for testing strategies for stimulating retina regeneration. Key to retina regeneration in zebrafish and mice is the Müller glial cell, a malleable cell type that is amenable to a variety of regenerative strategies. Here, we review cellular and molecular mechanisms used by zebrafish to regenerate a retina, as well as the application of these mechanisms, and other strategies to stimulate retina regeneration in mice. Although our focus is on Müller glia (MG), niche components and their impact on MG reprogramming are also discussed.

Imidazoline receptors as a new therapeutic target in Huntington's disease: A preclinical overview

An autosomal dominant neurodegenerative disease called Huntington's disease (HD) is characterized by motor dysfunction, cognitive decline, and a variety of psychiatric symptoms due to the expansion of polyglutamine in the Huntingtin gene. The disease primarily affects the striatal neurons within the basal ganglia, leading to significant neuronal loss and associated symptoms such as chorea and dystonia. Current therapeutic approaches focus on symptom management without altering the disease's progression, highlighting a pressing need for novel treatment strategies. Recent studies have identified imidazoline receptors (IRs) as promising targets for neuroprotective and disease-modifying interventions in HD. IRs, particularly the I1 and I2 subtypes, are involved in critical physiological processes such as neurotransmission, neuronal excitability, and cell survival. Activation of these receptors has been shown to modulate neurotransmitter release and provide neuroprotective effects in preclinical models of neurodegeneration. This review discusses the potential of IR-targeted therapies to not only alleviate multiple symptoms of HD but also possibly slow the progression of the disease. We emphasize the necessity for ongoing research to further elucidate the role of IRs in HD and develop selective ligands that could lead to effective and safe treatments, thereby significantly improving patient outcomes and quality of life.

GHRH and its analogues in central nervous system diseases

Growth hormone-releasing hormone (GHRH) is primarily produced by the hypothalamus and stimulates the release of growth hormone (GH) in the anterior pituitary gland, which subsequently regulates the production of hepatic insulin-like growth factor-1 (IGF-1). GH and IGF-1 have potent effects on promoting cell proliferation, inhibiting cell apoptosis, as well as regulating cell metabolism. In central nerve system (CNS), GHRH/GH/IGF-1 promote brain development and growth, stimulate neuronal proliferation, and regulate neurotransmitter release, thereby participating in the regulation of various CNS physiological activities. In addition to hypothalamus-pituitary gland, GHRH and GHRH receptor (GHRH-R) are also expressed in other brain cells or tissues, such as endogenous neural stem cells (NSCs) and tumor cells. Alternations in GHRH/GH/IGF-1 axis are associated with various CNS diseases, for example, Alzheimer's disease, amyotrophic lateral sclerosis and emotional disorders manifest GHRH, GH or IGF-1 deficiency, and GH or IGF-1 supplementation exerts beneficial therapeutic effects on these diseases. CNS tumors, such as glioma, can express GHRH and GHRH-R, and activating this signaling pathway promotes tumor cell growth. The synthesized GHRH antagonists have shown to inhibit glioma cell growth and may hold promising as an adjuvant therapy for treating glioma. In addition, we have shown that GHRH agonist MR-409 can improve neurological sequelae after ischemic stroke by activating extrapituitary GHRH-R signaling and promoting endogenous NSCs-derived neuronal regeneration. This article reviews the involvement of GHRH/GH/IGF-1 in CNS diseases, and potential roles of GHRH agonists and antagonists in treating CNS diseases.

Ketogenic diet in clinical populations-a narrative review

Ketogenic diet (KD) is a high-fat, low-carbohydrate (CHO) diet, designed to induce a metabolic state of ketosis in which the body metabolizes primarily lipids for energy production. Various forms of KD are being promoted as promising treatments for numerous health conditions from chronic headaches to weight-loss and even different forms of cancer and are becoming increasingly more popular. KD appears to be an efficacious approach for weight-loss, and maintenance, improved glycemia, cognitive function and cancer prognosis. However, there is a controversy regarding the safety of KD, and the potential health risks that might be associated with long-term exposure to KD. There is a gap between the acceptance and utilization of KD in individuals with health conditions and the criticism and negative attitudes toward KD by some clinicians. Many individuals choose to follow KD and are encouraged by the positive results they experience. Although the medical establishment does not endorse KD as a first line of treatment, clinicians need to be informed about KD, and offer support and medical supervision for patients who self-select to follow KD. This can ensure that within the boundaries of KD, patients will make good and healthy dietary choices and prevent clinical disengagement in extreme cases. To that end, there is an urgent need for good quality research to address the issues of long-term safety of KD in different clinical populations and for standardization of KD both in research and in the clinic.

Regulation of Diseases-Associated Microglia in the Optic Nerve by Lipoxin B4 and Ocular Hypertension

Background

The resident astrocyte-retinal ganglion cell (RGC) lipoxin circuit is impaired during retinal stress, which includes ocular hypertension-induced neuropathy. Lipoxin B4 produced by homeostatic astrocytes directly acts on RGCs to increase survival and function in ocular hypertension-induced neuropathy. RGC death in the retina and axonal degeneration in the optic nerve are driven by the complex interactions between microglia and macroglia. Whether LXB4 neuroprotective actions include regulation of other cell types in the retina and/or optic nerve is an important knowledge gap.

Methods

Cellular targets and signaling of LXB4 in the retina were defined by single-cell RNA sequencing. Retinal neurodegeneration was induced by injecting silicone oil into the anterior chamber of the mouse eyes, which induced sustained and stable ocular hypertension. Morphological characterization of microglia populations in the retina and optic nerve was established by MorphOMICs and pseudotime trajectory analyses. The pathways and mechanisms of action of LXB4 in the optic nerve were investigated using bulk RNA sequencing. Transcriptomics data was validated by qPCR and immunohistochemistry. Differences between experimental groups were assessed by Student's t-test and one-way ANOVA.

Results

Single-cell transcriptomics identified microglia as a primary target for LXB4 in the healthy retina. LXB4 downregulated genes that drive microglia environmental sensing and reactivity responses. Analysis of microglial function revealed that ocular hypertension induced distinct, temporally defined, and dynamic phenotypes in the retina and, unexpectedly, in the distal myelinated optic nerve. Microglial expression of CD74, a marker of disease-associated microglia in the brain, was only induced in a unique population of optic nerve microglia, but not in the retina. Genetic deletion of lipoxin formation correlated with the presence of a CD74 optic nerve microglia population in normotensive eyes, while LXB4 treatment during ocular hypertension shifted optic nerve microglia toward a homeostatic morphology and non-reactive state and downregulated the expression of CD74. Furthermore, we identified a correlation between CD74 and phospho-phosphoinositide 3-kinases (p-PI3K) expression levels in the optic nerve, which was reduced by LXB4 treatment.

Conclusion

We identified early and dynamic changes in the microglia functional phenotype, reactivity, and induction of a unique CD74 microglia population in the distal optic nerve as key features of ocular hypertension-induced neurodegeneration. Our findings establish microglia regulation as a novel LXB4 target in the retina and optic nerve. LXB4 maintenance of a homeostatic optic nerve microglia phenotype and inhibition of a disease-associated phenotype are potential neuroprotective mechanisms for the resident LXB4 pathway.

Acquisition of neurodegenerative features in isogenic OPTN(E50K) human stem cell-derived retinal ganglion cells associated with autophagy disruption and mTORC1 signaling reduction

The ability to derive retinal ganglion cells (RGCs) from human pluripotent stem cells (hPSCs) has led to numerous advances in the field of retinal research, with great potential for the use of hPSC-derived RGCs for studies of human retinal development, in vitro disease modeling, drug discovery, as well as their potential use for cell replacement therapeutics. Of all these possibilities, the use of hPSC-derived RGCs as a human-relevant platform for in vitro disease modeling has received the greatest attention, due to the translational relevance as well as the immediacy with which results may be obtained compared to more complex applications like cell replacement. While several studies to date have focused upon the use of hPSC-derived RGCs with genetic variants associated with glaucoma or other optic neuropathies, many of these have largely described cellular phenotypes with only limited advancement into exploring dysfunctional cellular pathways as a consequence of the disease-associated gene variants. Thus, to further advance this field of research, in the current study we leveraged an isogenic hPSC model with a glaucoma-associated mutation in the Optineurin (OPTN) protein, which plays a prominent role in autophagy. We identified an impairment of autophagic-lysosomal degradation and decreased mTORC1 signaling via activation of the stress sensor AMPK, along with subsequent neurodegeneration in OPTN(E50K) RGCs differentiated from hPSCs, and have further validated some of these findings in a mouse model of ocular hypertension. Pharmacological inhibition of mTORC1 in hPSC-derived RGCs recapitulated disease-related neurodegenerative phenotypes in otherwise healthy RGCs, while the mTOR-independent induction of autophagy reduced protein accumulation and restored neurite outgrowth in diseased OPTN(E50K) RGCs. Taken together, these results highlighted that autophagy disruption resulted in increased autophagic demand which was associated with downregulated signaling through mTORC1, contributing to the degeneration of RGCs.

Therapeutic potential of mesenchymal stem cell-derived exosomes and miRNAs in neuronal regeneration and rejuvenation in neurological disorders: a mini review

Mesenchymal stem cells (MSCs) have gained considerable attention in the field of regenerative medicine due to their ability to secrete small extracellular vesicles (EVs) known as exosomes. This review delves into the various biological activities of MSCs and the cell interactions enabled by these exosomes, with a focus on their potential for neuronal regeneration and the treatment of neurological disorders. We scrutinize findings from multiple studies that underscore the neuroprotective and neuro-regenerative effects of exosomes derived from MSCs, illuminating their mechanisms of action and therapeutic applications. This review thoroughly investigates all related pathways, miRNAs, and factors to suggest potential strategies for enhancing therapy for neurological disorders using exosomes and miRNAs, and for boosting neuronal regeneration.

Beyond hypertrophy: Changing views of astrocytes in glaucoma

Astrocytes serve multiple roles in helping to maintain homeostatic physiology of central nervous system tissue, ranging from metabolic support to coupling between vascular and neural elements. Astrocytes are especially critical in axonal tracts such as the optic nerve, where axons propagate energy-demanding action potentials great distances. In disease, astrocyte remodeling is a dynamic, multifaceted process that is often over-simplified between states of quiescence and reactivity. In glaucoma, axon degeneration in the optic nerve is characterized by progressive stages. So too is astrocyte remodeling. Here, using quantitative analysis of light and electron micrographs of myelinated optic nerve sections from the DBA/2J mouse model of glaucoma, we offer further insight into how astrocyte organization reflects stages of degeneration. This analysis indicates that even as axons degenerate, astrocyte gliosis in the nerve increases without abject proliferation, similar to results in the DBA/2J retina. Gliosis is accompanied by reorganization. As axons expand prior to frank degeneration, astrocyte processes retract from the extra-axonal space and reorient towards the nerve edge. After a critical threshold of expansion, axons drop out, and astrocyte processes distribute more evenly across the nerve reflecting gliosis. This multi-stage process likely reflects local rather than global cues from axons and the surrounding tissue that induce rapid reorganization to promote axon survival and extend functionality of the nerve.

Glial cell activation precedes neurodegeneration in the cerebellar cortex of the YG8-800 murine model of Friedreich ataxia

Friedreich ataxia is a hereditary neurodegenerative disorder resulting from reduced levels of the protein frataxin due to an expanded GAA repeat in the FXN gene. This deficiency causes progressive degeneration of specific neuronal populations in the cerebellum and the consequent loss of movement coordination and equilibrium, which are some of the main symptoms observed in affected individuals. Like in other neurodegenerative diseases, previous studies suggest that glial cells could be involved in the neurodegenerative process and disease progression in patients with Friedreich ataxia. In this work, we followed and characterized the progression of changes in the cerebellar cortex in the latest version of Friedreich ataxia humanized mouse model, YG8-800 (Fxnnull:YG8s(GAA)>800), which carries a human FXN transgene containing >800 GAA repeats. Comparative analyses of behavioral, histopathological, and biochemical parameters were conducted between the control strain Y47R and YG8-800 mice at different time points. Our findings revealed that YG8-800 mice exhibit an ataxic phenotype characterized by poor motor coordination, decreased body weight, cerebellar atrophy, neuronal loss, and changes in synaptic proteins. Additionally, early activation of glial cells, predominantly astrocytes and microglia, was observed preceding neuronal degeneration, as was increased expression of key proinflammatory cytokines and downregulation of neurotrophic factors. Together, our results show that the YG8-800 mouse model exhibits a stronger phenotype than previous experimental murine models, reliably recapitulating some of the features observed in humans. Accordingly, this humanized model could represent a valuable tool for studying Friedreich ataxia molecular disease mechanisms and for preclinical evaluation of possible therapies.

Peri-implantitis with a potential axis to brain inflammation: an inferential review

Peri-implantitis (PI) is a chronic, inflammatory, and infectious disease which affects dental implants and has certain similarities to periodontitis (PD). Evidence has shown that PD may be related to several types of systemic disorders, such as diabetes and insulin resistance, cardiovascular diseases, respiratory tract infections, adverse pregnancy outcomes, and neurological disorders. Furthermore, some types of bacteria in PD can also be found in PI, leading to certain similarities in the immunoinflammatory responses in the host. This review aims to discuss the possible connection between PI and neuroinflammation, using information based on studies about periodontal disorders, a topic whose connection with systemic alterations has been gaining the interest of the scientific community. Literature concerning PI, PD, and systemic disorders, such as neuroinflammation, brain inflammation, and neurological disorder, was searched in the PubMed database using different keyword combinations. All studies found were included in this narrative review. No filters were used. Eligible studies were analyzed and reviewed carefully. This study found similarities between PI and PD development, maintenance, and in the bacterial agents located around the teeth (periodontitis) or dental implants (peri-implantitis). Through the cardiovascular system, these pathologies may also affect blood-brain barrier permeability. Furthermore, scientific evidence has suggested that microorganisms from PI (as in PD) can be recognized by trigeminal fiber endings and start inflammatory responses into the trigeminal ganglion. In addition, bacteria can traverse from the mouth to the brain through the lymphatic system. Consequently, the immune system increases inflammatory mediators in the brain, affecting the homeostasis of the nervous tissue and vice-versa. Based on the interrelation of microbiological, inflammatory, and immunological findings between PD and PI, it is possible to infer that immunoinflammatory changes observed in PD can imply systemic changes in PI. This, as discussed, could lead to the development or intensification of neuroinflammatory changes, contributing to neurodegenerative diseases.

Tear Proteomics in Children and Adolescents with Type 1 Diabetes: A Promising Approach to Biomarker Identification of Diabetes Pathogenesis and Complications

The aim of the current study was to investigate the tear proteome in children and adolescents with type 1 diabetes (T1D) compared to healthy controls, and to identify differences in the tear proteome of children with T1D depending on different characteristics of the disease. Fifty-six children with T1D at least one year after diagnosis, aged 6-17 years old, and fifty-six healthy age- and sex-matched controls were enrolled in this cross-sectional study. The proteomic analysis was based on liquid chromatography tandem mass spectrometry (LC-MS/MS) enabling the identification and quantification of the protein content via Data-Independent Acquisition by Neural Networks (DIA-NN). Data are available via ProteomeXchange with the identifier PXD052994. In total, 3302 proteins were identified from tear samples. Two hundred thirty-nine tear proteins were differentially expressed in children with T1D compared to healthy controls. Most of them were involved in the immune response, tissue homeostasis and inflammation. The presence of diabetic ketoacidosis at diagnosis and the level of glycemic control of children with T1D influenced the tear proteome. Tear proteomics analysis revealed a different proteome pattern in children with T1D compared to healthy controls offering insights on deregulated biological processes underlying the pathogenesis of T1D. Differences within the T1D group could unravel biomarkers for early detection of long-term complications of T1D.

The Use of Neurotrophic Factors as a Promising Strategy for the Treatment of Neurodegenerative Diseases (Review)

The review considers the use of exogenous neurotrophic factors in the treatment of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, and others. This group of diseases is associated with the death of neurons and dysfunction of the nervous tissue. Currently, there is no effective therapy for neurodegenerative diseases, and their treatment remains a serious problem of modern medicine. A promising strategy is the use of exogenous neurotrophic factors. Targeted delivery of these factors to the nervous tissue can improve survival of neurons during the development of neurodegenerative processes and ensure neuroplasticity. There are methods of direct injection of neurotrophic factors into the nervous tissue, delivery using viral vectors, as well as the use of gene cell products. The effectiveness of these approaches has been studied in numerous experimental works and in a number of clinical trials. Further research in this area could provide the basis for the creation of an alternative treatment for neurodegenerative diseases.

Genetic, transcriptomic, histological, and biochemical analysis of progressive supranuclear palsy implicates glial activation and novel risk genes

Progressive supranuclear palsy (PSP), a rare Parkinsonian disorder, is characterized by problems with movement, balance, and cognition. PSP differs from Alzheimer's disease (AD) and other diseases, displaying abnormal microtubule-associated protein tau by both neuronal and glial cell pathologies. Genetic contributors may mediate these differences; however, the genetics of PSP remain underexplored. Here we conduct the largest genome-wide association study (GWAS) of PSP which includes 2779 cases (2595 neuropathologically-confirmed) and 5584 controls and identify six independent PSP susceptibility loci with genome-wide significant (P < 5 × 10-8) associations, including five known (MAPT, MOBP, STX6, RUNX2, SLCO1A2) and one novel locus (C4A). Integration with cell type-specific epigenomic annotations reveal an oligodendrocytic signature that might distinguish PSP from AD and Parkinson's disease in subsequent studies. Candidate PSP risk gene prioritization using expression quantitative trait loci (eQTLs) identifies oligodendrocyte-specific effects on gene expression in half of the genome-wide significant loci, and an association with C4A expression in brain tissue, which may be driven by increased C4A copy number. Finally, histological studies demonstrate tau aggregates in oligodendrocytes that colocalize with C4 (complement) deposition. Integrating GWAS with functional studies, epigenomic and eQTL analyses, we identify potential causal roles for variation in MOBP, STX6, RUNX2, SLCO1A2, and C4A in PSP pathogenesis.

Biallelic ZBTB11 Variants: A Neurodevelopmental Condition with Progressive Complex Movement Disorders

BACKGROUND

Biallelic ZBTB11 variants have previously been associated with an ultrarare subtype of autosomal recessive intellectual developmental disorder (MRT69).

OBJECTIVE

The aim was to provide insights into the clinical and genetic characteristics of ZBTB11-related disorders (ZBTB11-RD), with a particular emphasis on progressive complex movement abnormalities.

METHODS

Thirteen new and 16 previously reported affected individuals, ranging in age from 2 to 50 years, with biallelic ZBTB11 variants underwent clinical and genetic characterization.

RESULTS

All patients exhibited a range of neurodevelopmental phenotypes with varying severity, encompassing ocular and neurological features. Eleven new patients presented with complex abnormal movements, including ataxia, dystonia, myoclonus, stereotypies, and tremor, and 7 new patients exhibited cataracts. Deep brain stimulation was successful in treating 1 patient with generalized progressive dystonia. Our analysis revealed 13 novel variants.

CONCLUSIONS

This study provides additional insights into the clinical features and spectrum of ZBTB11-RD, highlighting the progressive nature of movement abnormalities in the background of neurodevelopmental phenotype.

Redox Homeostasis, Gut Microbiota, and Epigenetics in Neurodegenerative Diseases: A Systematic Review

Neurodegenerative diseases encompass a spectrum of disorders marked by the progressive degeneration of the structure and function of the nervous system. These conditions, including Parkinson's disease (PD), Alzheimer's disease (AD), Huntington's disease (HD), Amyotrophic lateral sclerosis (ALS), and Multiple sclerosis (MS), often lead to severe cognitive and motor deficits. A critical component of neurodegenerative disease pathologies is the imbalance between pro-oxidant and antioxidant mechanisms, culminating in oxidative stress. The brain's high oxygen consumption and lipid-rich environment make it particularly vulnerable to oxidative damage. Pro-oxidants such as reactive nitrogen species (RNS) and reactive oxygen species (ROS) are continuously generated during normal metabolism, counteracted by enzymatic and non-enzymatic antioxidant defenses. In neurodegenerative diseases, this balance is disrupted, leading to neuronal damage. This systematic review explores the roles of oxidative stress, gut microbiota, and epigenetic modifications in neurodegenerative diseases, aiming to elucidate the interplay between these factors and identify potential therapeutic strategies. We conducted a comprehensive search of articles published in 2024 across major databases, focusing on studies examining the relationships between redox homeostasis, gut microbiota, and epigenetic changes in neurodegeneration. A total of 161 studies were included, comprising clinical trials, observational studies, and experimental research. Our findings reveal that oxidative stress plays a central role in the pathogenesis of neurodegenerative diseases, with gut microbiota composition and epigenetic modifications significantly influencing redox balance. Specific bacterial taxa and epigenetic markers were identified as potential modulators of oxidative stress, suggesting novel avenues for therapeutic intervention. Moreover, recent evidence from human and animal studies supports the emerging concept of targeting redox homeostasis through microbiota and epigenetic therapies. Future research should focus on validating these targets in clinical settings and exploring the potential for personalized medicine strategies based on individual microbiota and epigenetic profiles.

Insulin restores retinal ganglion cell functional connectivity and promotes visual recovery in glaucoma

Dendrite pathology and synaptic loss result in neural circuit dysfunction, a common feature of neurodegenerative diseases. There is a lack of strategies that target dendritic and synaptic regeneration to promote neurorecovery. We show that daily human recombinant insulin eye drops stimulate retinal ganglion cell (RGC) dendrite and synapse regeneration during ocular hypertension, a risk factor to develop glaucoma. We demonstrate that the ribosomal protein p70S6 kinase (S6K) is essential for insulin-dependent dendritic regrowth. Furthermore, S6K phosphorylation of the stress-activated protein kinase-interacting protein 1 (SIN1), a link between the mammalian target of rapamycin complexes 1 and 2 (mTORC1/2), is required for insulin-induced dendritic regeneration. Using two-photon microscopy live retinal imaging, we show that insulin rescues single-RGC light-evoked calcium (Ca2+) dynamics. We further demonstrate that insulin enhances neuronal survival and retina-brain connectivity leading to improved optomotor reflex-elicited behaviors. Our data support that insulin is a compelling pro-regenerative strategy with potential clinical implications for the treatment and management of glaucoma.

Luteolin for neurodegenerative diseases: a review

Neurodegenerative diseases such as Parkinson's disease, Alzheimer's disease, Huntington's disease, and multiple sclerosis affect millions of people around the world. In addition to age, which is a key factor contributing to the development of all neurodegenerative diseases, genetic and environmental components are also important risk factors. Current methods of treating neurodegenerative diseases are mostly symptomatic and do not eliminate the cause of the disease. Many studies focus on searching for natural substances with neuroprotective properties that could be used as an adjuvant therapy in the inhibition of the neurodegeneration process. These compounds include flavonoids, such as luteolin, showing significant anti-inflammatory, antioxidant, and neuroprotective activity. Increasing evidence suggests that luteolin may confer protection against neurodegeneration. In this review, we summarize the scientific reports from preclinical in vitro and in vivo studies regarding the beneficial effects of luteolin in neurodegenerative diseases. Luteolin was studied most extensively in various models of Alzheimer's disease but there are also several reports showing its neuroprotective effects in models of Parkinson's disease. Though very limited, studies on possible protective effects of luteolin against Huntington's disease and multiple sclerosis are also discussed here. Overall, although preclinical studies show the potential benefits of luteolin in neurodegenerative disorders, clinical evidence on its therapeutic efficacy is still deficient.

Neurodegenerative disorders: Mechanisms of degeneration and therapeutic approaches with their clinical relevance

Neurodegenerative disorders (NDs) are expected to pose a significant challenge for both medicine and public health in the upcoming years due to global demographic changes. NDs are mainly represented by degeneration/loss of neurons, which is primarily accountable for severe mental illness. This neuronal degeneration leads to many neuropsychiatric problems and permanent disability in an individual. Moreover, the tight junction of the brain, blood-brain barrier (BBB)has a protective feature, functioning as a biological barrier that can prevent medicines, toxins, and foreign substances from entering the brain. However, delivering any medicinal agent to the brain in NDs (i.e., Multiple sclerosis, Alzheimer's, Parkinson's, etc.) is enormously challenging. There are many approved therapies to address NDs, but most of them only help treat the associated manifestations. The available therapies have failed to control the progression of NDs due to certain factors, i.e., BBB and drug-associated undesirable effects. NDs have extremely complex pathology, with many pathogenic mechanisms involved in the initiation and progression; thereby, a limited survival rate has been observed in ND patients. Hence, understanding the exact mechanism behind NDs is crucial to developing alternative approaches for improving ND patients' survival rates. Thus, the present review sheds light on different cellular mechanisms involved in NDs and novel therapeutic approaches with their clinical relevance, which will assist researchers in developing alternate strategies to address the limitations of conventional ND therapies. The current work offers the scope into the near future to improve the therapeutic approach of NDs.

NG2 glia protect against prion neurotoxicity by inhibiting microglia-to-neuron prostaglandin E2 signaling

Oligodendrocyte-lineage cells, including NG2 glia, undergo prominent changes in various neurodegenerative disorders. Here, we identify a neuroprotective role for NG2 glia against prion toxicity. NG2 glia were activated after prion infection in cerebellar organotypic cultured slices (COCS) and in brains of prion-inoculated mice. In both model systems, depletion of NG2 glia exacerbated prion-induced neurodegeneration and accelerated prion pathology. Loss of NG2 glia enhanced the biosynthesis of prostaglandin E2 (PGE2) by microglia, which augmented prion neurotoxicity through binding to the EP4 receptor. Pharmacological or genetic inhibition of PGE2 biosynthesis attenuated prion-induced neurodegeneration in COCS and mice, reduced the enhanced neurodegeneration in NG2-glia-depleted COCS after prion infection, and dampened the acceleration of prion disease in NG2-glia-depleted mice. These data unveil a non-cell-autonomous interaction between NG2 glia and microglia in prion disease and suggest that PGE2 signaling may represent an actionable target against prion diseases.

Contributions of Brain Microstructures and Metabolism to Visual Field Loss Patterns in Glaucoma Using Archetypal and Information Gain Analyses

Purpose

To investigate the contributions of the microstructural and metabolic brain environment to glaucoma and their association with visual field (VF) loss patterns by using advanced diffusion magnetic resonance imaging (dMRI), proton magnetic resonance spectroscopy (MRS), and clinical ophthalmic measures.

Methods

Sixty-nine glaucoma and healthy subjects underwent dMRI and/or MRS at 3 Tesla. Ophthalmic data were collected from VF perimetry and optical coherence tomography. dMRI parameters of microstructural integrity in the optic radiation and MRS-derived neurochemical levels in the visual cortex were compared among early glaucoma, advanced glaucoma, and healthy controls. Multivariate regression was used to correlate neuroimaging metrics with 16 archetypal VF loss patterns. We also ranked neuroimaging, ophthalmic, and demographic attributes in terms of their information gain to determine their importance to glaucoma.

Results

In dMRI, decreasing fractional anisotropy, radial kurtosis, and tortuosity and increasing radial diffusivity correlated with greater overall VF loss bilaterally. Regionally, decreasing intra-axonal space and extra-axonal space diffusivities correlated with greater VF loss in the superior-altitudinal area of the right eye and the inferior-altitudinal area of the left eye. In MRS, both early and advanced glaucoma patients had lower gamma-aminobutyric acid (GABA), glutamate, and choline levels than healthy controls. GABA appeared to associate more with superonasal VF loss, and glutamate and choline more with inferior VF loss. Choline ranked third for importance to early glaucoma, whereas radial kurtosis and GABA ranked fourth and fifth for advanced glaucoma.

Conclusions

Our findings highlight the importance of non-invasive neuroimaging biomarkers and analytical modeling for unveiling glaucomatous neurodegeneration and how they reflect complementary VF loss patterns.

Rethinking neurodegenerative diseases: neurometabolic concept linking lipid oxidation to diseases in the central nervous system

ABSTRACT

Currently, there is a lack of effective medicines capable of halting or reversing the progression of neurodegenerative disorders, including amyotrophic lateral sclerosis, Parkinson's disease, multiple sclerosis, or Alzheimer's disease. Given the unmet medical need, it is necessary to reevaluate the existing paradigms of how to target these diseases. When considering neurodegenerative diseases from a systemic neurometabolic perspective, it becomes possible to explain the shared pathological features. This innovative approach presented in this paper draws upon extensive research conducted by the authors and researchers worldwide. In this review, we highlight the importance of metabolic mitochondrial dysfunction in the context of neurodegenerative diseases. We provide an overview of the risk factors associated with developing neurodegenerative disorders, including genetic, epigenetic, and environmental factors. Additionally, we examine pathological mechanisms implicated in these diseases such as oxidative stress, accumulation of misfolded proteins, inflammation, demyelination, death of neurons, insulin resistance, dysbiosis, and neurotransmitter disturbances. Finally, we outline a proposal for the restoration of mitochondrial metabolism, a crucial aspect that may hold the key to facilitating curative therapeutic interventions for neurodegenerative disorders in forthcoming advancements.