Progression Of Neurodegenerative Diseases Research Articles

Current challenges for therapy of comorbid patients: a new look at celecoxib. A review

The use of non-steroidal anti-inflammatory drugs (NSAIDs) for a wide range of diseases is increasing, in part due to an increasing elderly population. Elderly patients are more vulnerable to adverse drug reactions, including side effects and adverse effects of drug-drug interactions, often occurring in this category of patients due to multimorbidity and polypharmacy. One of the most popular NSAIDs in the world is celecoxib. It is a selective cyclooxygenase (COX)-2 inhibitor with 375 times more COX-2 inhibitory activity than COX-1. As a result, celecoxib has a better gastrointestinal tract safety profile than non-selective NSAIDs. Gastrointestinal tolerance is an essential factor that physicians should consider when selecting NSAIDs for elderly patients. Celecoxib can be used in a wide range of diseases of the musculoskeletal system and rheumatological diseases, for the treatment of acute pain in women with primary dysmenorrhea, etc. It is also increasingly used as part of a multimodal perioperative analgesia regimen. There is strong evidence that COX-2 is actively involved in the pathogenesis of ischemic brain damage, as well as in the development and progression of neurodegenerative diseases, such as Alzheimer's disease. NSAIDs are first-line therapy in the treatment of acute migraine attacks. Celecoxib is well tolerated in patients with risk factors for NSAID-associated nephropathy. It does not decrease the glomerular filtration rate in elderly patients and patients with chronic renal failure. Many meta-analyses and epidemiological studies have not confirmed the increased risk of cardiovascular events reported in previous clinical studies and have not shown an increased risk of cardiovascular events with celecoxib, irrespective of dose. COX-2 activation is one of the key factors contributing to obesity-related inflammation. Specific inhibition of COX-2 by celecoxib increases insulin sensitivity in overweight or obese patients. Combination therapies may be a promising new area of treatment for obesity and diabetes.

Could Alcohol-Related Cognitive Decline Be the Result of Iron-Induced Neuroinflammation?

Excessive and prolonged alcohol use can have long-term severe neurological consequences. The mechanisms involved may be complicated; however, new evidence seems to indicate the involvement of iron accumulation and neuroinflammation. Prolonged alcohol consumption has been linked to the accumulation of iron in specific regions of the brain. Evidence suggests that excess iron in the brain can trigger microglia activation in response. This activation leads to the release of pro-inflammatory cytokines and reactive oxygen species, which can cause damage to neurons and surrounding brain tissue. Additionally, iron-induced oxidative stress and inflammation can disrupt the blood-brain barrier, allowing immune cells from the periphery to infiltrate the brain. This infiltration can lead to further neuroinflammatory responses. Inflammation in the brain subsequently disrupts neuronal networks, impairs synaptic plasticity, and accelerates neuronal cell death. Consequently, cognitive functions such as memory, attention, and decision-making are compromised. Additionally, chronic neuroinflammation can hasten the development and progression of neurodegenerative diseases, further exacerbating cognitive impairment. Therefore, alcohol could act as a trigger for iron-induced neuroinflammation and cognitive decline. Overall, the mechanisms at play here seem to strongly link alcohol with cognitive decline, with neuroinflammation resulting from alcohol-induced iron accumulation playing a pivotal role.

Polytopal discontinuous Galerkin discretization of brain multiphysics flow dynamics

A comprehensive mathematical model of the multiphysics flow of blood and Cerebrospinal Fluid (CSF) in the brain can be expressed as the coupling of a poromechanics system and Stokes' equations: the first describes fluids filtration through the cerebral tissue and the tissue's elastic response, while the latter models the flow of the CSF in the brain ventricles. This model describes the functioning of the brain's waste clearance mechanism, which has been recently discovered to play an essential role in the progress of neurodegenerative diseases. To model the interactions between different scales in the porous medium, we propose a physically consistent coupling between Multi-compartment Poroelasticity (MPE) equations and Stokes' equations. In this work, we introduce a numerical scheme for the discretization of such coupled MPE-Stokes system, employing a high-order discontinuous Galerkin method on polytopal grids to efficiently account for the geometric complexity of the domain. We analyze the stability and convergence of the space semidiscretized formulation, we prove a-priori error estimates, and we present a temporal discretization based on a combination of Newmark's β-method for the elastic wave equation and the θ-method for the other equations of the model. Numerical simulations carried out on test cases with manufactured solutions validate the theoretical error estimates. We also present numerical results on a two-dimensional slice of a patient-specific brain geometry reconstructed from diagnostic images, to test in practice the advantages of the proposed approach.

MicroRNAs in microglia: deciphering their role in neurodegenerative diseases.

This review presents a comprehensive analysis of the role of microRNAs in microglia and their implications in the pathogenesis of neurodegenerative diseases. Microglia, as the resident immune cells of the central nervous system (CNS), are pivotal in maintaining neural homeostasis and responding to pathological changes. Recent studies have highlighted the significance of miRNAs, small non-coding RNA molecules, in regulating microglial functions. In neurodegenerative diseases, such as Alzheimer's Disease (AD), Parkinson's Disease (PD), Amyotrophic Lateral Sclerosis (ALS), and Multiple Sclerosis (MS), dysregulated miRNA expression in microglia contributes to disease progression through various mechanisms such regulation of gene expression, as modulation of cytokine response and phagocytosis. This review synthesizes current knowledge on how miRNAs influence microglial activation, cytokine production, and phagocytic activity. Specific miRNAs, such as miR-155, are explored for their roles in modulating microglial responses in the context of neuroinflammation and neurodegeneration. The study also discusses the impact of miRNA dysregulation on the transition of microglia from a neuroprotective to a neurotoxic phenotype, a critical aspect in the progression of neurodegenerative diseases.

Catecholamines: Influence on healthy aging and the progression of neurodegenerative diseases

Catecholamines: Influence on healthy aging and the progression of neurodegenerative diseases

Assessing the contribution of the chemical exposome to neurodegenerative disease.

Over the past few decades, numerous environmental chemicals from solvents to pesticides have been suggested to be involved in the development and progression of neurodegenerative diseases. Most of the evidence has accumulated from occupational or cohort studies in humans or laboratory research in animal models, with a range of chemicals being implicated. What has been missing is a systematic approach analogous to genome-wide association studies, which have identified dozens of genes involved in Alzheimer's disease, Parkinson's disease and other neurodegenerative diseases. Fortunately, it is now possible to study hundreds to thousands of chemical features under the exposome framework. This Perspective explores how advances in mass spectrometry make it possible to generate exposomic data to complement genomic data and thereby better understand neurodegenerative diseases.

An integrative miRNA-mRNA expression analysis identifies miRNA signatures associated with SOD1 and TARDBP patient-derived motor neurons.

MicroRNAs (miRNAs) are a subset of small non-coding single-stranded RNA molecules involved in the regulation of post-transcriptional gene expression of a variety of transcript targets. Therefore altered miRNA expression may result in the dysregulation of key genes and biological pathways that has been reported with the onset and progression of neurodegenerative diseases, such as Amyotrophic lateral sclerosis (ALS). ALS is marked by a progressive degeneration of motor neurons (MNs) present in the spinal cord, brain stem and motor cortex. Although the pathomechanism underlying molecular interactions of ALS remains poorly understood, alterations in RNA metabolism, including dysregulation of miRNA expression in familial as well as sporadic forms are still scarcely studied. In this study, we performed combined transcriptomic data and miRNA profiling in MN samples of the same samples of iPSC-derived MNs from SOD1- and TARDBP (TDP-43 protein)-mutant-ALS patients and healthy controls. We report a global upregulation of mature miRNAs, and suggest that differentially expressed (DE) miRNAs have a significant impact on mRNA-level in SOD1-, but not in TARDBP-linked ALS. Furthermore, in SOD1-ALS we identified dysregulated miRNAs such as miR-124-3p, miR-19b-3p and miR-218 and their potential targets previously implicated in important functional process and pathogenic pathways underlying ALS. These miRNAs may play key roles in the neuronal development and cell survival related functions in SOD1-ALS. Altogether, we provide evidence of miRNA regulated genes expression mainly in SOD1 rather than TDP43-ALS.

Sleep, glymphatic system, and Parkinson’s disease

Sleep is involved in regulating many aspects of the body, including cell function, physical activity, and disease. Neurodegenerative diseases are often preceded by sleep disturbance. This disturbance is not just a non-motor symptom but also an important risk factor for developing the disease. It is now understood that the glymphatic system plays important physiological functions in the human body: maintaining the balance of interstitial fluid and clearing waste products from metabolism or death in the brain. Glymphatic system dysfunction contributes to the progression of neurodegenerative diseases. Importantly, sleep is involved in regulating the glymphatic system, which affects the clearance of pathological proteins in the brain, and may be an important pathway affecting the progression of neurodegenerative diseases. Here, we review recent advances in sleep disturbances and the glymphatic system in health and Parkinson's disease, hoping to identify potentially targetable avenues for future research and treatment of Parkinson's disease.

Associations of plasma neurofilament light chain with cognition and neuroimaging measures in community-dwelling early old age men

BackgroundPlasma neurofilament light chain (NfL) is a promising biomarker of neurodegeneration with potential clinical utility in monitoring the progression of neurodegenerative diseases. However, the cross-sectional associations of plasma NfL with measures of cognition and brain have been inconsistent in community-dwelling populations.MethodsWe examined these associations in a large community-dwelling sample of early old age men (N = 969, mean age = 67.57 years, range = 61–73 years), who are either cognitively unimpaired (CU) or with mild cognitive impairment (MCI). Specifically, we investigated five cognitive domains (executive function, episodic memory, verbal fluency, processing speed, visual-spatial ability), as well as neuroimaging measures of gray and white matter.ResultsAfter adjusting for age, health status, and young adult general cognitive ability, plasma NfL level was only significantly associated with processing speed and white matter hyperintensity (WMH) volume, but not with other cognitive or neuroimaging measures. The association with processing speed was driven by individuals with MCI, as it was not detected in CU individuals.ConclusionsThese results suggest that in early old age men without dementia, plasma NfL does not appear to be sensitive to cross-sectional individual differences in most domains of cognition or neuroimaging measures of gray and white matter. The revealed plasma NfL associations were limited to WMH for all participants and processing speed only within the MCI cohort. Importantly, considering cognitive status in community-based samples will better inform the interpretation of the relationships of plasma NfL with cognition and brain and may help resolve mixed findings in the literature.

Traumatic Brain Injury: Role in Induction and Progression of Neurodegenerative Disorders

Background: Traumatic brain injury (TBI) affects a huge proportion of population worldwide. TBI is the most common epigenetic health risk for neurological illness later in life. Different post-injury mechanisms may contribute to neurodegeneration. Thus, it is associated with a greater risk of neurodegenerative diseases for instance Parkinson’s disease (PD), depression, epilepsy, amyotrophic lateral sclerosis (ALS), Alzheimer’s disease (AD) and chronic traumatic encephalopathy (CTE). Objective: The present study encapsulates the neurodegenerative effects trigged by TBI. Therefore, understanding of such triggers may be helpful in prediction, early diagnosis or the management of neurodegenerative diseases in patients who had TBI. Further, understanding of TBI-induced neuronal damage may provide better knowledge for drug development, disease management, and check of induction and progression of neurodegenerative diseases. Conclusion: Several approaches show a strong correlation between TBI secondary injury and various neurodegenerative diseases involving oxidative stress and numerous neuroinflammationdiseases. It appears that oxidative stress plays a crucial role in both TBI and neurodegeneration by causing neuroinflammation and glutamatergicexcitotoxicity.

Artificial intelligence in diagnosis of neurodegenerative disorders (literature review)

Currently, there are virtually no objective diagnostic signs (markers) to diagnose neurodegenerative diseases, that is why it may take months of constant monitoring of symptoms to establish a reliable diagnosis. Now there is an increasing number of reports that artificial intelligence can provide a more accurate diagnosis of neurodegenerative diseases by identifying specific diagnostic features from electroencephalography data, neuroimaging, and wearable devices and smartphones. This study reviews the application of artificial intelligence to the diagnosis of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and Huntington's disease. Using the international databases Scopus and PubMed, as well as the Russian Science Citation Index, we analysed studies that used artificial intelligence methods to detect, monitor, or control the progression of neurodegenerative diseases. The primary focus is on analysing electroencephalography data, neuroimaging data, and data from wearable devices and smartphones. The use of the latter may allow screening, diagnosis, and monitoring of the disease at home with a minimum economic cost. Artificial intelligence can be a useful tool for early, accurate, and non-invasive diagnosis of neurodegenerative diseases, as well as for assessing the effectiveness of treatment and predicting the course of the disease. However, for the widespread implementation of artificial intelligence in clinical practice, several issues related to the quality, availability, and standardization of data, validation and interpretation of results, ethical and legal aspects need to be resolved. The use of artificial intelligence requires both specialists from the IT industry with a deep understanding of the types and kinds of neural networks and physicians with fundamental knowledge of neurology, psychiatry, molecular biology, and biophysics.

Investigating the Roles of Gut Microbiome in the Progression of Neurodegenerative Diseases: Alzheimer's, Parkinson's, and Amyotrophic Lateral Sclerosis (ALS)

Neurodegenerative diseases (NDs), such as Alzheimer’s disease (AD), Parkinson’s disease (PD), and Amyotrophic Lateral Sclerosis (ALS), pose global health burdens due to their incurable and degenerative nature. Emerging evidence highlights the complex interplay between the gut microbiome and the central nervous system (CNS), revealing novel mechanisms of ND pathogenesis and progression. This review integrates current literature, correlation analyses, and inferential statistics to elucidate the impact of gut microbiome dysbiosis on NDs and identify potential diagnostic biomarkers and therapeutic targets. The gut-brain axis (GBA), a bidirectional communication network between the gut and the brain, modulates neurological function and disease outcomes. Correlation analyses demonstrated significant associations between gut microbiome perturbations and ND parameters, implying a causal role for gut dysbiosis in ND pathogenesis. Inferential statistics revealed distinct microbial profiles between ND cohorts and healthy controls, indicating a shared gut dysbiosis across diverse NDs. Studies investigating microbial taxa, metabolites, and signaling pathways have provided insights into the molecular mechanisms underlying gut microbiome-mediated effects on neurodegeneration. Elucidating the reciprocal interactions between the gut microbiome and the host physiology is essential for deciphering the GBA’s role in NDs. Despite advances, knowledge gaps remain. Longitudinal studies are required to monitor gut microbiome dynamics over ND progression. Mechanistic studies are needed to establish how gut microbiome composition affects disease. Methodological standardization for gut microbiome assessment is imperative for rigorous research. Future endeavors should aim to translate findings into clinical applications to exploit microbiome-based interventions for enhanced neurological outcomes in NDs.

The Influence of Myeloid-Derived Suppressor Cell Expansion in Neuroinflammation and Neurodegenerative Diseases.

The neuro-immune axis has a crucial function both during physiological and pathological conditions. Among the immune cells, myeloid-derived suppressor cells (MDSCs) exert a pivotal role in regulating the immune response in many pathological conditions, influencing neuroinflammation and neurodegenerative disease progression. In chronic neuroinflammation, MDSCs could lead to exacerbation of the inflammatory state and eventually participate in the impairment of cognitive functions. To have a complete overview of the role of MDSCs in neurodegenerative diseases, research on PubMed for articles using a combination of terms made with Boolean operators was performed. According to the search strategy, 80 papers were retrieved. Among these, 44 papers met the eligibility criteria. The two subtypes of MDSCs, monocytic and polymorphonuclear MDSCs, behave differently in these diseases. The initial MDSC proliferation is fundamental for attenuating inflammation in Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS), but not in amyotrophic lateral sclerosis (ALS), where MDSC expansion leads to exacerbation of the disease. Moreover, the accumulation of MDSC subtypes in distinct organs changes during the disease. The proliferation of MDSC subtypes occurs at different disease stages and can influence the progression of each neurodegenerative disorder differently.

Machine learning based on the EEG and structural MRI can predict different stages of vascular cognitive impairment.

Vascular cognitive impairment (VCI) is a major cause of cognitive impairment in the elderly and a co-factor in the development and progression of most neurodegenerative diseases. With the continuing development of neuroimaging, multiple markers can be combined to provide richer biological information, but little is known about their diagnostic value in VCI. A total of 83 subjects participated in our study, including 32 patients with vascular cognitive impairment with no dementia (VCIND), 21 patients with vascular dementia (VD), and 30 normal controls (NC). We utilized resting-state quantitative electroencephalography (qEEG) power spectra, structural magnetic resonance imaging (sMRI) for feature screening, and combined them with support vector machines to predict VCI patients at different disease stages. The classification performance of sMRI outperformed qEEG when distinguishing VD from NC (AUC of 0.90 vs. 0,82), and sMRI also outperformed qEEG when distinguishing VD from VCIND (AUC of 0.8 vs. 0,0.64), but both underperformed when distinguishing VCIND from NC (AUC of 0.58 vs. 0.56). In contrast, the joint model based on qEEG and sMRI features showed relatively good classification accuracy (AUC of 0.72) to discriminate VCIND from NC, higher than that of either qEEG or sMRI alone. Patients at varying stages of VCI exhibit diverse levels of brain structure and neurophysiological abnormalities. EEG serves as an affordable and convenient diagnostic means to differentiate between different VCI stages. A machine learning model that utilizes EEG and sMRI as composite markers is highly valuable in distinguishing diverse VCI stages and in individually tailoring the diagnosis.

Diosgenin loaded cellulose nanoonion impedes different stages of protein aggregation induced cell death via alleviating mitochondrial dysfunction and upregulation of autophagy

Protein aggregation is a multifaceted phenomenon prevalent in the progression of neurodegenerative diseases, yielding aggregates of diverse sizes. Recently, increased attention has been directed towards early protein aggregates due to their pronounced toxicity, largely stemming from inflammation mediated by reactive oxygen species (ROS). This study advocates for a therapeutic approach focusing on inflammation control rather than mere ROS inhibition in the context of neurodegenerative disorders. Here, we introduced Camellia sinensis cellulose nanoonion (CS-CNO) as an innovative, biocompatible nanocarrier for encapsulating the phytosteroid diosgenin (DGN@CS-CNO). The resulting nano-assembly, manifesting as spherical entities with dimensions averaging ~180–220 nm, exhibits a remarkable capacity for the gradual and sustained release of approximately 39–44 % of DGN over a 60-hour time frame. DGN@CS-CNO displays a striking ability to inhibit or disassemble various phases of hen egg white lysozyme (HEWL) protein aggregates, including the early (HEWLEA) and late (HEWLLA) stages. In vitro experiments employing HEK293 cells underscore the potential of DGN@CS-CNO in mitigating cell death provoked by protein aggregation. This effect is achieved by ameliorating ROS-mediated inflammation and countering mitochondrial dysfunction, as evidenced by alterations in TNFα, TLR4, and MT-CO1 protein expression. Western blot analyses reveal that the gradual and sustained release of DGN from DGN@CS-CNO induces autophagy, a pivotal process in dismantling intracellular amyloid deposits. In summary, this study not only illuminates a path forward but also presents a compelling case for the utilization of phytosteroid as a formidable strategy against neuroinflammation incited by protein aggregation.

Abstract 7476: Obtusifolin attenuates LPS-induced inflammation and NLRP3 inflammasome activation by suppressing the MAPK/NF-κB signaling pathway and ROS production in BV2 cells

Abstract Neuroinflammation, along with activation of microglia and oxidative stress, plays an important role in the development and progression of neurodegenerative diseases. During the inflammation process, immune cells release inflammatory mediators such as cytokines and chemicals that may promote the formation and growth of cancer cells. Obtusifolin, an anthraquinone extracted from the seeds of Senna obtusifolin, has anti-inflammatory properties. However, the effect of obtusifolin on neuroinflammation and its regulatory mechanism have not been yet investigated. In the present study, BV2 microglial cells were used to investigate the effects of obtusifolin on LPS-induced inflammatory responses, NLRP3 inflammasome activation, and reactive oxygen species (ROS) production. The secretion of nitric oxide (NO) was analyzed by Griess reagent assay, and the cell viability was detected by the CCK-8 assay. The expressions of iNOS, COX-2, STAT3, ERK, JNK, and p38 were examined using Western blotting, and the production of IL-6 and TNF-α was measured by ELISA. To examine whether obtusifolin affected NLRP3 inflammasome activation, BV2 cells were pretreated with LPS and then stimulated with ATP or nigericin. The secretion of IL-1β was measured by ELISA, whereas the expression of NLRP3 inflammasome-related proteins was detected using Western blotting. The production of ROS was analyzed by flow cytometry. Our experimental results showed that obtusifolin suppressed the production of NO and the secretion of proinflammatory cytokines by LPS-induced BV2 cells under noncytotoxic concentrations. In addition, obtusifolin decreased the expression of iNOS, COX-2, phospho-STAT3, phospho-ERK, phosphor-JNK and phospho-p38, and also attenuated the expression of NLRP3 and ASC, cleaved caspase-1 and cleaved IL-1β by LPS- induced BV2 cells. Moreover, obtusifolin reduced the production of both intracellular and mitochondrial ROS by LPS-induced BV2 cells. Overall, these results demonstrated that obtusifolin attenuated LPS-induced inflammation by suppressing the activation of MAPK and NF-κB signaling pathways, inhibiting NLRP3 inflammasome activation, and reducing the production of ROS in microglia, suggesting that obtusifolin might have benefits in the treatment of neurodegenerative diseases. Citation Format: Hsin Yi Lin, Che-Hsin Lee, Chia-Yang Li. Obtusifolin attenuates LPS-induced inflammation and NLRP3 inflammasome activation by suppressing the MAPK/NF-κB signaling pathway and ROS production in BV2 cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7476.

Targeting Neuroinflammation by Pharmacologic Downregulation of Inflammatory Pathways Is Neuroprotective in Protein Misfolding Disorders.

Neuroinflammation plays a crucial role in the development of neurodegenerative protein misfolding disorders. This category of progressive diseases includes, but is not limited to, Alzheimer's disease, Parkinson's disease, and prion diseases. Shared pathogenesis involves the accumulation of misfolded proteins, chronic neuroinflammation, and synaptic dysfunction, ultimately leading to irreversible neuronal loss, measurable cognitive deficits, and death. Presently, there are few to no effective treatments to halt the advancement of neurodegenerative diseases. We hypothesized that directly targeting neuroinflammation by downregulating the transcription factor, NF-κB, and the inflammasome protein, NLRP3, would be neuroprotective. To achieve this, we used a cocktail of RNA targeting therapeutics (SB_NI_112) shown to be brain-penetrant, nontoxic, and effective inhibitors of both NF-κB and NLRP3. We utilized a mouse-adapted prion strain as a model for neurodegenerative diseases to assess the aggregation of misfolded proteins, glial inflammation, neuronal loss, cognitive deficits, and lifespan. Prion-diseased mice were treated either intraperitoneally or intranasally with SB_NI_112. Behavioral and cognitive deficits were significantly protected by this combination of NF-κB and NLRP3 downregulators. Treatment reduced glial inflammation, protected against neuronal loss, prevented spongiotic change, rescued cognitive deficits, and significantly lengthened the lifespan of prion-diseased mice. We have identified a nontoxic, systemic pharmacologic that downregulates NF-κB and NLRP3, prevents neuronal death, and slows the progression of neurodegenerative diseases. Though mouse models do not always predict human patient success and the study was limited due to sample size and number of dosing methods utilized, these findings serve as a proof of principle for continued translation of the therapeutic SB_NI_112 for prion disease and other neurodegenerative diseases. Based on the success in a murine prion model, we will continue testing SB_NI_112 in a variety of neurodegenerative disease models, including Alzheimer's disease and Parkinson's disease.

The effects of cholesterol and statins on Parkinson's neuropathology: a narrative review.

Parkinson disease (PD) is chronic and progressive neurodegenerative disease of the brain characterized by motor symptoms including tremors, rigidity, postural instability, and bradykinesia. PD neuropathology is due to the progressive degeneration of dopaminergic neurons in the substantia nigra and accumulation of Lewy bodies in the survival neurons. The brain contains a largest amount of cholesterol which is mainly synthesized from astrocytes and glial cells. Cholesterol is intricate in the pathogenesis of PD and may be beneficial or deleterious. Therefore, there are controversial points concerning the role of cholesterol in PD neuropathology. In addition, cholesterol-lowering agents' statins can affect brain cholesterol. Different studies highlighted that statins, via inhibition of brain HMG-CoA, can affect neuronal integrity through suppression of neuronal cholesterol, which regulates synaptic plasticity and neurotransmitter release. Furthermore, statins affect the development and progression of different neurodegenerative diseases in bidirectional ways that could be beneficial or detrimental. Therefore, the objective of the present review was to clarify the double-sward effects of cholesterol and statins on PD neuropathology.

HFE Mutations in Neurodegenerative Disease as a Model of Hormesis.

Common variants in the iron regulatory protein HFE contribute to systematically increased iron levels, yet the effects in the brain are not fully characterized. It is commonly believed that iron dysregulation is a key contributor to neurodegenerative disease due to iron's ability to catalyze reactive oxygen species production. However, whether HFE variants exacerbate or protect against neurodegeneration has been heavily debated. Some claim that mutated HFE exacerbates oxidative stress and neuroinflammation, thus predisposing carriers to neurodegeneration-linked pathologies. However, H63D HFE has also been shown to slow the progression of multiple neurodegenerative diseases and to protect against environmental toxins that cause neurodegeneration. These conflicting results showcase the need to further understand the contribution of HFE variants to neurodegenerative disease heterogeneity. Data from mouse models consistently demonstrate robust neuroprotection against toxins known to increase the risk of neurodegenerative disease. This may represent an adaptive, or hormetic, response to increased iron, which leaves cells better protected against future stressors. This review describes the current research regarding the contribution of HFE variants to neurodegenerative disease prognosis in the context of a hormetic model. To our knowledge, this is the first time that a hormetic model for neurodegenerative disease has been presented.

Stable knockdown of Drp1 improves retinoic acid-BDNF-induced neuronal differentiation through global transcriptomic changes and results in reduced phosphorylation of ERK1/2 independently of DUSP1 and 6.

Background: Dynamin-related protein Drp1 -a major mitochondrial fission protein- is widely distributed in the central nervous system and plays a crucial role in regulating mitochondrial dynamics, specifically mitochondrial fission and the organelle's shaping. Upregulated Drp1 function may contribute to the pathological progression of neurodegenerative diseases by dysregulating mitochondrial fission/ fusion. The study aims to investigate the effects of Drp1 on retinoic acid-BDNF-induced (RA-BDNF) neuronal differentiation and mitochondrial network reorganization in SH-SY5Y neuroblastoma cells. Methods: We generated an SH-SY5Y cell line with stably depleted Drp1 (shDrp1). We applied RNA sequencing and analysis to study changes in gene expression upon stable Drp1 knockdown. We visualized the mitochondria by transmission electron microscopy and used high-content confocal imaging to characterize and analyze cell morphology changes and mitochondrial network reorganization during neuronal differentiation. Results: shDrp1 cells exhibited fused mitochondrial ultrastructure with perinuclear clustering. Stable knockdown of Drp1 resulted in the upregulation of genes involved in nervous system development. High content analysis showed improved neurite outgrowth, segmentation, and extremities in differentiated shDrp1 cells. Neuronal differentiation was associated with a significant reduction in ERK1/2 phosphorylation, and ERK1/2 phosphorylation was independent of the dual specificity phosphatases DUSP1/6 in shDrp1 cells. Differentiated control underwent mitochondrial morphology remodeling, whereas differentiated shDrp1 cells retained the highly fused mitochondria and developed long, elongated structures. The shDrp1 cells responded to specific apoptotic stimuli like control in vitro, suggesting that Drp1 is not a prerequisite for apoptosis in SH-SY5Y cells. Moreover, Drp1 downregulation reduced the formation of toxic mHtt aggregates in vitro. Discussion: Our results indicate that Drp1 silencing enhances RA-BDNF-induced neuronal differentiation by promoting transcriptional and mitochondrial network changes in undifferentiated cells. We also demonstrate that the suppression of Drp1 reduces toxic mHtt aggregate formation in vitro, suggesting protection against neurotoxicity. Thus, Drp1 may be an attractive target for further investigation in future strategies to combat neurodegenerative diseases.