Nanotechnological Approaches for Mitochondrial Targeting in Neurodegenerative Diseases.

Extracellular vesicles (EVs) are small bilipid layer-enclosed vesicles that can be secreted by all tested types of brain cells. Being a key intercellular communicator, EVs have emerged as a key contributor to the pathogenesis of various neurodegenerative diseases (NDs) including Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, and Huntington’s disease through delivery of bioactive cargos within the central nervous system (CNS). Importantly, CNS cell-derived EVs can be purified via immunoprecipitation, and EV cargos with altered levels have been identified as potential biomarkers for the diagnosis and prognosis of NDs. Given the essential impact of EVs on the pathogenesis of NDs, pathological EVs have been considered as therapeutic targets and EVs with therapeutic effects have been utilized as potential therapeutic agents or drug delivery platforms for the treatment of NDs. In this review, we focus on recent research progress on the pathological roles of EVs released from CNS cells in the pathogenesis of NDs, summarize findings that identify CNS-derived EV cargos as potential biomarkers to diagnose NDs, and comprehensively discuss promising potential of EVs as therapeutic targets, agents, and drug delivery systems in treating NDs, together with current concerns and challenges for basic research and clinical applications of EVs regarding NDs.

Neurodegenerative diseases (NDs) like Alzheimer's disease, multiple sclerosis, amyotrophic lateral sclerosis, Parkinson's disease, and Huntington's disease predominantly pose a significant socioeconomic burden. Characterized by progressive neural dysfunction coupled with motor or intellectual impairment, the pathogenesis of ND may result from contributions of certain environmental and molecular factors. One such condition is hypoxia, characterized by reduced organ/tissue exposure to oxygen. Reduced oxygen supply often occurs during the pathogenesis of ND and the aging process. Despite the well-established relationship between these two conditions (i.e., hypoxia and ND), the underlying molecular events or mechanisms connecting hypoxia to ND remain ill-defined. However, the relatedness may stem from the protective or deleterious effects of the transcription factor, hypoxia-inducible factor 1-alpha (HIF-1α). The upregulation of HIF-1α occurs in the pathogenesis of most NDs. The dual function of HIF-1α in acting as a “killer factor” or a “protective factor” depends on the prevailing local cellular condition. The kynurenine pathway is a metabolic pathway involved in the oxidative breakdown of tryptophan. It is essential in neurotransmission and immune function and, like hypoxia, associated with ND. Thus, a good understanding of factors, including hypoxia (i.e., the biochemical implication of HIF-1α) and kynurenine pathway activation in NDs, focusing on Alzheimer's disease could prove beneficial to new therapeutic approaches for this disease, thus the aim of this review.

Neurodegenerative disorders are characterized by progressive loss of particular populations of neurons. Apoptosis has been implicated in the pathogenesis of neurodegenerative diseases, including Parkinson disease, Alzheimer disease, Huntington disease, and amyotrophic lateral sclerosis. In this review, we focus on the existing notions relevant to comprehending the apoptotic death process, including the morphological features, mediators and regulators of cellular apoptosis. We also highlight the evidence of neuronal apoptotic death in Parkinson disease, Alzheimer disease, Huntington disease, and amyotrophic lateral sclerosis. Additionally, we present evidence of potential therapeutic agents that could modify the apoptotic pathway in the aforementioned neurodegenerative diseases and delay disease progression. Finally, we review the clinical trials that were conducted to evaluate the use of anti‐apoptotic drugs in the treatment of the aforementioned neurodegenerative diseases, in order to highlight the essential need for early detection and intervention of neurodegenerative diseases in humans.

With the gradual advancement of research methods and technologies, various biological processes have been identified as playing roles in the pathogenesis of neurodegenerative diseases. However, current descriptions of these biological processes do not fully explain the onset, progression, and development of these conditions. Therefore, exploration of the pathogenesis of neurodegenerative diseases remains a valuable area of research. This review summarizes the potential common pathogeneses of Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, frontotemporal lobar dementia, and Lewy body disease. Research findings have indicated that several common biological processes, including aging, genetic factors, progressive neuronal dysfunction, neuronal death and apoptosis, protein misfolding and aggregation, neuroinflammation, mitochondrial dysfunction, axonal transport defects, and gut microbiota dysbiosis, are involved in the pathogenesis of these six neurodegenerative diseases. Based on current information derived from diverse areas of research, these biological processes may form complex pathogenic networks that lead to distinctive types of neuronal death in neurodegenerative diseases. Furthermore, promoting the regeneration of damaged neurons may be achievable through the repair of affected neural cells if the underlying pathogenesis can be prevented or reversed. Hence, these potential common biological processes may represent only very small, limited elements within numerous intricate pathogenic networks associated with neurodegenerative diseases. In clinical treatment, interfering with any single biological process has proven insufficient to completely halt the progression of neurodegenerative diseases. Therefore, future research on the pathogenesis of neurodegenerative diseases should focus on uncovering the complex pathogenic networks, rather than isolating individual biological processes. Based on this, therapies that aim to block or reverse various targets involved in the potential pathogenic mechanisms of neurodegenerative diseases may be promising directions, as current treatment methods that focus on halting a single pathogenic factor have not achieved satisfactory efficacy.

Objective:To estimate risks of neurodegenerative and psychiatric diseases among patients with amyotrophic lateral sclerosis (ALS) and their families.Methods:We conducted a register-based nested case-control study during 1990–2013 in Sweden to assess whether patients with ALS had higher risks of other neurodegenerative and psychiatric diseases before diagnosis. We included 3,648 patients with ALS and 36,480 age-, sex-, and county of birth–matched population controls. We further conducted a follow-up study of the cases and controls to assess the risks of other neurodegenerative and psychiatric diseases after ALS diagnosis. To assess the potential contribution of familial factors, we conducted similar studies for the relatives of patients with ALS and their controls.Results:Individuals with previous neurodegenerative or psychiatric diseases had a 49% increased risk of ALS (odds ratio 1.49, 95% confidence interval 1.35–1.66) compared to individuals without these diseases. After diagnosis, patients with ALS had increased risks of other neurodegenerative or psychiatric diseases (hazard ratio 2.90, 95% confidence interval 2.46–3.43) compared to individuals without ALS. The strongest associations were noted for frontotemporal dementia, Parkinson disease, other dementia, Alzheimer disease, neurotic disorders, depression, stress-related disorders, and drug abuse/dependence. First-degree relatives of patients with ALS had higher risk of neurodegenerative diseases, whereas only children of patients with ALS had higher risk of psychiatric disorders, compared to relatives of the controls.Conclusions:Familial aggregation of ALS and other neurodegenerative diseases implies a shared etiopathogenesis among all neurodegenerative diseases. The increased risk of psychiatric disorders among patients with ALS and their children might be attributable to nonmotor symptoms of ALS and severe stress response toward the diagnosis.

Aberrant Protein S-Nitrosylation in Neurodegenerative Diseases

The nuclear pore is the gatekeeper of nucleocytoplasmic transport and signaling through which a vast flux of information is continuously exchanged between the nuclear and cytoplasmic compartments to maintain cellular homeostasis. A unifying and organizing principle has recently emerged that cements the notion that several forms of amyotrophic lateral sclerosis (ALS), and growing number of other neurodegenerative diseases, co-opt the dysregulation of nucleocytoplasmic transport and that this impairment is a pathogenic driver of neurodegeneration. The understanding of shared pathomechanisms that underpin neurodegenerative diseases with impairments in nucleocytoplasmic transport and how these interface with current concepts of nucleocytoplasmic transport is bound to illuminate this fundamental biological process in a yet more physiological context. Here, I summarize unresolved questions and evidence and extend basic and critical concepts and challenges of nucleocytoplasmic transport and its role in the pathogenesis of neurodegenerative diseases, such as ALS. These principles will help to appreciate the roles of nucleocytoplasmic transport in the pathogenesis of ALS and other neurodegenerative diseases, and generate a framework for new ideas of the susceptibility of motoneurons, and possibly other neurons, to degeneration by dysregulation of nucleocytoplasmic transport.

Targeting the epigenome to treat neurodegenerative diseases or delay their onset: a perspective

CNS-targeted Viral Delivery of G-CSF in an Animal Model for ALS: Improved Efficacy and Preservation of the Neuromuscular Unit

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.

Neurodegenerative diseases (NDs) are common chronic diseases with unknown etiology, and the association between virus and its pathogenesis is not clear. The aim of this study is to explore the role of virus in the pathogenesis of NDs by analyzing the causal effect between infectious mononucleosis (IM) mainly caused by Epstein–Barr virus and NDs. Based on the summary statistics of a large-scale genome-wide association study, we analyzed the causal effects of IM and NDs by Mendelian randomization (MR) using genetic variants as instrumental variables, including Alzheimer disease, Parkinson disease, amyotrophic lateral sclerosis, and multiple sclerosis. The reliability and stability of the MR analysis results were assessed by the MR-Egger intercept test, MR-PRESSO test, and heterogeneity test. Twenty-two single nucleotide polymorphisms that were significantly and strongly associated with IM were used as instrumental variables in the MR analysis. Inverse variance weighted as the main method of MR analysis shows that there were significant causal effects between IM and Alzheimer disease (OR: 1.037, 95% CI: 1.006–1.070) and Parkinson disease (OR: 0.964, 95% CI: 0.930–1.000), while IM was not significantly associated with amyotrophic lateral sclerosis (P = .269) and multiple sclerosis (P = .182). Sensitivity analyses showed that the results were robust. This study suggests that EB virus may contribute to the pathogenesis of NDs, and more research is needed to explore the specific mechanism of virus action on NDs.

A Long Shot? Could neurodegenerative disease be caused by a cyanobacterial toxin?

Background:Adult-onset neurodegenerative diseases affect millions and negatively impact health care systems worldwide. Evidence suggests that air pollution may contribute to aggravation of neurodegeneration, but studies have been limited.Objective:We examined the potential association between long-term exposure to particulate matter in aerodynamic diameter [fine particulate matter ()] and disease aggravation in Alzheimer’s (AD) and Parkinson’s (PD) diseases and amyotrophic lateral sclerosis (ALS), using first hospitalization as a surrogate of clinical aggravation.Methods:We used data from the New York Department of Health Statewide Planning and Research Cooperative System (SPARCS 2000–2014) to construct annual county counts of first hospitalizations with a diagnosis of AD, PD, or ALS (total, urbanicity-, sex-, and age-stratified). We used annual concentrations estimated by a prediction model at a resolution, which we aggregated to population-weighted county averages to assign exposure to cases based on county of residence. We used outcome-specific mixed quasi-Poisson models with county-specific random intercepts to estimate rate ratios (RRs) for a 1-y exposure. We allowed for nonlinear exposure–outcome relationships using penalized splines and accounted for potential confounders.Results:We found a positive nonlinear association that plateaued above (, 95% CI: 1.04, 1.14 for a increase from 8.1 to ). We also found a linear positive association (, 95% CI: 1.01, 1.09 per increase), and suggestive evidence of an association with AD. We found effect modification by age for PD and ALS with a stronger positive association in patients of age but found insufficient evidence of effect modification by sex or urbanization level for any of the outcomes.Conclusion:Our findings suggest that annual increase in county-level concentrations may contribute to clinical aggravation of PD and ALS. Importantly, the average annual concentration in our study was , below the current American national standards, suggesting the standards may not adequately protect the aging population. https://doi.org/10.1289/EHP7425

In this review, we discuss examples that show how glial-cell pathology is increasingly recognized in several neurodegenerative diseases. We also discuss the more provocative idea that some of the disorders that are currently considered to be neurodegenerative diseases might, in fact, be due to primary abnormalities in glia. Although the mechanism of glial pathology (i.e. modulating glutamate excitotoxicity) might be better established for amyotrophic lateral sclerosis (ALS), a role for neuronal-glial interactions in the pathogenesis of most neurodegenerative diseases is plausible. This burgeoning area of neuroscience will receive much attention in the future and it is expected that further understanding of basic neuronal-glial interactions will have a significant impact on the understanding of the fundamental nature of human neurodegenerative disorders.

Nervous tissues from both humans with neurodegenerative diseases (NDD) and animals with genetic models of human NDD, such as rare monogenic causes of Amyotrophic Lateral Sclerosis (ALS), Alzheimer’s disease (AD), and Parkinson’s disease (PD), show activated microglia, suggesting a potential causal role for inflammation in pathogenesis of NDD. We performed paired-end (PE) RNA sequencing (RNA seq) of total RNA’s extracted from frozen sections of cervical spinal cords from ALS and CTL subjects, frontal cortical gray matter ribbons of AD and CTL subjects, and ventral midbrains of PD and CTL subjects. Trimmed PE reads were aligned against the hg38 human transcriptome using Tophat2/Bowtie2 (ALS) or HISAT2 (AD and PD) and quantitated with Cufflinks. PE reads were also aligned using Bowtie2 against genomes from representative species of Toxoplasma gondii and Trichinella sp. T6 (parasitic infectious agents), Babesia microti and Borrelia burgdorferi (tick-vector borne agents), and Treponema denticola and Porphyromonas gingivalis, agents causing chronic gingivitis. Primary aligned reads of each agent in each tissue sample were quantitated with SAMtools. We found small percentages (<0.1%) of transcriptomes aligned with B. microti, B. burgdorferi, T. denticola, and P. gingivalis genomes and larger percentages aligned with T. gondii (0.1–0.2%) and Trichinella sp. T6 (1.0–1.1%) genomes. In AD specimens, but in no others, primary aligned transcriptome percentages, although small, approached significance for being greater in AD compared to CTL samples for B. burgdorferi (p = 0.067) and P. gingivalis (p = 0.068). Genes’ expressions in postmortem tissues of AD and ALS but not PD revealed significant changes among disease-associated microglial (DAM) genes. Infectious agents’ transcripts can be detected in RNA seq reads of both NDD and CTL tissues and vary from agent to agent. Expressions of Stage 1 and Stage 2 DAM genes significantly changed, suggesting the presence of Stages 1 and 2 DAM in our NDD tissue samples.