Parkinson disease

Exploring the versatility of Drosophila melanogaster as a model organism in biomedical research: a comprehensive review

Drosophila melanogaster is a highly versatile model organism that has profoundly advanced our understanding of human diseases. With more than 60% of its genes having human homologs, Drosophila provides an invaluable system for modelling a wide range of pathologies, including neurodegenerative disorders, cancer, metabolic diseases, as well as cardiac and muscular conditions. This review highlights key developments in utilizing Drosophila for disease modelling, emphasizing the genetic tools that have transformed research in this field. Technologies such as the GAL4/UAS system, RNA interference (RNAi) and CRISPR-Cas9 have enabled precise genetic manipulation, with CRISPR-Cas9 allowing for the introduction of human disease mutations into orthologous Drosophila genes. These approaches have yielded critical insights into disease mechanisms, identified novel therapeutic targets and facilitated both drug screening and toxicological studies. Articles were selected based on their relevance, impact and contribution to the field, with a particular focus on studies offering innovative perspectives on disease mechanisms or therapeutic strategies. Our findings emphasize the central role of Drosophila in studying complex human diseases, underscoring its genetic similarities to humans and its effectiveness in modelling conditions such as Alzheimer's disease, Parkinson's disease and cancer. This review reaffirms Drosophila's critical role as a model organism, highlighting its potential to drive future research and therapeutic advancements.

In silico screening of peptide inhibitors targeting α-synuclein for Parkinson's disease

Parkinson's disease affects cognitive, motor, and autonomic functions due to nervous system degeneration. Though no cure exists, medications and therapies can help alleviate symptoms, but their effectiveness diminishes as the disease progresses, ultimately increasing the need for alternative treatments. α-Synuclein has long been one of the main targets in addressing Parkinson's through drug design studies, but no drugs are yet approved against α-Synuclein aggregation. Therefore, this study aims to develop potential inhibitors of fibrillization by screening thousands of peptides in terms of their binding abilities via Molecular Docking and Molecular Dynamics simulations. Our results show that peptides with Lysine and Arginine at terminal groups result in higher binding affinities to the C-terminal domain. Among the heptapeptides examined, RWRRKRL shows the highest binding free energy to the protein while KKRHKWR exhibits superior stabilizing effect, interacting with both N- and C-terminal regions of α-Synuclein. The inhibitory potential of peptides on the fibrillar structure of protein varies with concentration, and RWRRKRL at 1:3 protein-peptide monomer ratio shows promise as an inhibitor by reducing the internal H-bonds of the protein and increasing RMSD values. These results reveal that short-chain peptides can be designed against α-Synuclein oligomerization offering a potential therapeutic approach for preventing Parkinson's.

A positive allosteric modulator of α7 nicotinic receptor reduces levodopa-induced dyskinesias in hemi-parkinsonian mice

Parkinson's disease is a prevalent neurodegenerative disorder characterized by motor impairments including rigidity, bradykinesia and tremor. L-3,4-dihydroxyphenylalanine (L-DOPA) keeps being the standard treatment for Parkinson's disease. But long-term treatment often leads to L-DOPA induced dyskinesias (LIDs): abnormal involuntary movements (AIMs) that significantly impact patients' quality of life. Drugs acting on nicotinic acetylcholine receptors (nAChRs) have emerged as a potential treatment for managing LIDs, since nicotine, shows promise in alleviating LIDs in animal models. Positive allosteric modulators acting via nAChRs of classes α4β2 and α7, such as NS9283 and PNU120596, respectively, have demonstrated therapeutic benefits in preclinical studies using parkinsonian models. Here we investigate the actions of both NS9283 and PNU120596 acting independently or enhancing nicotine's therapeutic effects on LIDs, seeking for novel therapeutic strategies for LIDs management. We used both behavioral assessments and an in vitro pharmacological bioassay previously reported to evaluate striatal microcircuit activity at the histological level in brain slices of dyskinetic mice. Our results show that PNU120596 administered alone is a potent anti-dyskinetic drug, its action not being improved by the presence of nicotine. In contrast, NS9283 has no action administered alone and does not significantly improve nicotine actions. Behavioral results coincide with the in vitro bioassay using principal components analysis of calcium imaging activity: PNU120596 actions in the striatal microcircuit clearly reduce and change active neurons in agreement with dyskinesia reduction. These findings point towards striatal α7-nAChRs positive allosteric modulators as potentially novel adjuvant drugs to manage LIDs.

2-(Phenylamino)-7,8-dihydroquinazolin-5(6H)-one, a promising scaffold for MAO-B inhibitors with potential GSK3β targeting

Neurodegenerative disorders, such as Parkinson's disease and Alzheimer's disease, constitute pathological conditions of great relevance on health span and quality of life. The identification of novel therapeutic options, able to modulate the processes involved in the insurgence and progression of neurodegenerative disorders, represents an intriguing challenge of current research. Herein, a library of 36-membered 2-(phenylamino)-7,8-dihydroquinazolinone derivatives was synthesized and biologically evaluated as human MAO inhibitors. Some compounds able to inhibit MAO-B potently and selectively (Ki in the nanomolar range) were identified, and robust structure-activity relationships were drawn, supported by computational studies. Further biological assays revealed a safe profile for all derivatives and, for compounds selected as the best MAO-B inhibitors (4, 5, 13, 14) the following properties also emerged: (i) the ability to inhibit MAO-B activity in whole cells, with an effectiveness comparable or slight lower with respect to the reference safinamide; (ii) physicochemical parameters suggesting drug-likeness properties; (iii) the ability to inhibit, albeit weakly, GSK3β kinase (for compound 4). Within the whole series, compound 4 stood out as a promising lead for future optimization campaigns aimed to obtain useful drugs for the treatment of Alzheimer's and Parkinson's diseases.

Unraveling brain aging through the lens of oral microbiota

The oral cavity is a complex physiological community encompassing a wide range of microorganisms. Dysbiosis of oral microbiota can lead to various oral infectious diseases, such as periodontitis and tooth decay, and even affect systemic health, including brain aging and neurodegenerative diseases. Recent studies have highlighted how oral microbes might be involved in brain aging and neurodegeneration, indicating potential avenues for intervention strategies. In this review, we summarize clinical evidence demonstrating a link between oral microbes/oral infectious diseases and brain aging/neurodegenerative diseases, and dissect potential mechanisms by which oral microbes contribute to brain aging and neurodegeneration. We also highlight advances in therapeutic development grounded in the realm of oral microbes, with the goal of advancing brain health and promoting healthy aging.

Liposomes as versatile agents for the management of traumatic and nontraumatic central nervous system disorders: drug stability, targeting efficiency, and safety

Various nanoparticle-based drug delivery systems for the treatment of neurological disorders have been widely studied. However, their inability to cross the blood-brain barrier hampers the clinical translation of these therapeutic strategies. Liposomes are nanoparticles composed of lipid bilayers, which can effectively encapsulate drugs and improve drug delivery across the blood-brain barrier and into brain tissue through their targeting and permeability. Therefore, they can potentially treat traumatic and nontraumatic central nervous system diseases. In this review, we outlined the common properties and preparation methods of liposomes, including thin-film hydration, reverse-phase evaporation, solvent injection techniques, detergent removal methods, and microfluidics techniques. Afterwards, we comprehensively discussed the current applications of liposomes in central nervous system diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, traumatic brain injury, spinal cord injury, and brain tumors. Most studies related to liposomes are still in the laboratory stage and have not yet entered clinical trials. Additionally, their application as drug delivery systems in clinical practice faces challenges such as drug stability, targeting efficiency, and safety. Therefore, we proposed development strategies related to liposomes to further promote their development in neurological disease research.

Gut neuropeptide involvement in Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder affecting over 10 million people. A key pathological feature of PD is the accumulation of misfolded α-synuclein (aSyn) protein in the substantia nigra pars compacta. Aggregation of aSyn can form Lewy bodies that contribute to dopaminergic neuron degeneration and motor symptoms, such as tremor, rigidity, and bradykinesia. Beyond the central nervous system, aSyn aggregates have been detected in the gastrointestinal (GI) tract, suggesting a link between peripheral aSyn and nonmotor PD symptoms. GI symptoms, often preceding motor symptoms by up to 20 years, highlight the bidirectional communication between the central nervous system and the enteric nervous system (gut-brain axis) in PD. Although microbiome alterations and intestinal inflammation have been associated with PD, functional impacts on gut-brain signaling or aSyn aggregation remain unclear. Intestinal neuropeptides are key modulators of gut-brain communication, alter immune response to pathogens and environmental toxins, and may contribute to the function of the luminal gut barrier. Dysregulation of gut neuropeptide signaling, including vasoactive intestinal peptide, neuropeptide Y, calcitonin gene-related peptide, ghrelin, cholecystokinin, glucagon-like peptide 1, and substance P, have been associated with pathologic effects of PD in animal models. Despite their potential role in pathogenesis and disease modulation, gut neuropeptide roles in PD are underexplored. This article reviews current knowledge surrounding microbial metabolite and immune influences on gut neuropeptide signaling, aSyn aggregation in the enteric nervous system, and downstream neuroimmune pathway alterations within the context of PD and its mouse models.

Real-world performance evaluation of a telemonitoring system for Parkinson's disease symptom assessment

BACKGROUND

Parkinson's disease (PD) nurses constitute a reliable modality for appraising the motor status of patients, second only to expert neurologists. Consequently, employing PD nurses for the assessment of medical device performance is appreciated to be a fundamental benchmark in the field.

OBJECTIVE

To evaluate the precision of a telemonitoring device in measuring motor symptoms when utilized at patient's home during everyday life conditions.

METHODS

To ascertain the extent of correlation between device-reported outcomes and PD nurse assessments and the precision with which the device detects symptoms such as gait impairment, rest tremor, bradykinesia, and the presence of OFF, a total of 34 evaluations were conducted by a PD nurse at the patients' home, each lasting 3 h.

RESULTS

A robust correlation was noted for all three symptoms when analyzed at both 30-minute intervals and cumulatively over the entire 3-hour duration with Pearson's r range 0.68-0.76 and 0.83-0.90 respectively. Furthermore, substantial agreement was observed for the identification of the presence of all three symptoms with Cohen's kappa range from 0.61 to 0.71 across all 30-minute evaluations. Finally, the device demonstrates high accuracy in detecting rest tremor (90%), bradykinesia (89%), gait impairment (95%) and OFF state (94%).

CONCLUSION

This study evaluates for the first time the performance of a remote monitoring device, unobtrusively, at patients familiar environment, with a PD nurse present in non-scripted scenarios. The device exhibited commendable efficacy in the accurate detection of PD symptoms and state.

Chemogenetic Control of Striatal Astrocytes Improves Parkinsonian Motor Deficits in Mice

Parkinson's disease (PD) is characterized by the degeneration of dopaminergic nigrostriatal inputs, which causes striatal network dysfunction and leads to pronounced motor deficits. Recent evidence highlights astrocytes as a potential local source for striatal neuromodulation. There is substantial evidence for norepinephrine-mediated recruitment of cortical astrocyte activity during movement and locomotion. However, it is unclear how astrocytes in the striatum, a region devoid of norepinephrine neuromodulatory inputs, respond during locomotion. Moreover, it remains unknown how dopamine loss affects striatal astrocyte activity and whether astrocyte activity regulates behavioral deficits in PD. We addressed these questions by performing astrocyte-specific calcium recordings and manipulations using in vivo fiber photometry and chemogenetics. We find that locomotion elicits astrocyte calcium activity over a slower timescale than neurons. Acute pharmacological blockade of dopamine receptors only moderately reduced locomotion-related astrocyte activity. Yet, unilateral dopamine depletion significantly attenuated astrocyte calcium responses. Chemogenetic stimulation of Gi-coupled receptors partially improved this functional astrocyte deficit in dopamine-lesioned mice. In parallel, chemogenetic manipulation restored asymmetrical motor deficits and moderately improved open-field exploratory behavior. Together, our results establish a novel role for functional striatal astrocyte signaling in modulating motor function in PD and highlight non-neuronal targets for potential PD therapeutics.

Advancing Parkinson's diagnosis: seed amplification assay for α-synuclein detection in minimally invasive samples

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by tremor, rigidity, and bradykinesia, beginning with early loss of dopaminergic neurons in the ventrolateral substantia nigra and advancing to broader neurodegeneration in the midbrain. The clinical heterogeneity of PD and the lack of specific diagnostic tests present significant challenges, highlighting the need for reliable biomarkers for early diagnosis. Alpha-synuclein (α-Syn), a protein aggregating into Lewy bodies and neurites in PD patients, has emerged as a key biomarker due to its central role in PD pathophysiology and potential to reflect pathological processes. Additionally, α-Syn allows earlier differentiation between PD and other neurodegenerative disorders with similar symptoms. Currently, detection of α-Syn pathology in post-mortem brain tissue remains the primary means of achieving a conclusive diagnosis, often revealing significant misdiagnoses. Seed amplification assay (SAA), initially developed for prion diseases, has been adapted to detect α-Syn aggregates in cerebrospinal fluid, showing promise for early diagnosis. Recent studies have demonstrated that SAA can also detect α-Syn aggregates in peripheral samples collected via minimally invasive procedures, such as skin, olfactory mucosa, saliva, and blood. However, the lack of standardized protocols limits clinical application. Standardizing protocols is essential to improve assay reliability and enable accurate patient identification for emerging therapies. This review examines studies on SAA for detecting α-Syn aggregates in minimally invasive samples, focusing on sample collection, processing, and reaction conditions.

Withaferin A maintained microbiome and metabolome features in A53T transgenic mice via multi-omics integrated analysis

BACKGROUND

Withaferin A (WFA), a naturally occurring compound, has shown promise as a therapeutic agent for Parkinson's disease (PD), a neurodegenerative disorder associated with motor and gastrointestinal dysfunctions. However, its effects on gut microbiota metabolism remain poorly understood.

PURPOSE

This study aimed to elucidate the neuroprotective mechanisms of WFA in a PD mouse model by investigating its regulation of gut microbiota composition, metabolic pathways, and correlations with brain spatial metabolomics.

METHODS

Human SNCA-transgenic (A53T) mice were treated with WFA and evaluated using behavioral tests, immunohistochemistry, Western blot, and ELISA to assess motor/cognitive functions and PD-related pathology. Gut microbiota composition was analyzed via 16S rRNA sequencing, while untargeted fecal metabolomics and brain spatial metabolomics were employed to identify metabolic alterations.

RESULTS

WFA significantly improved motor performance, alleviated cognitive deficits, restored intestinal barrier integrity, and reduced neuroinflammation. It elevated the abundance of anti-inflammatory gut bacteria (e.g., Bifidobacterium, Dubosiella, Akkermansia) and reversed 55 fecal metabolites linked to sphingolipid metabolism, serotonergic synapses, and neuroactive ligand- receptor interactions. Spatial metabolomics revealed WFA's regulation of sphingolipid signaling pathways, including sphingosine kinase (Sphk1), ceramidase, sphingosine 1-phosphate receptor (S1PR5), and endocannabinoid receptor CB2 expression. Correlation analysis indicated a link between brain metabolite content and gut microbiota abundance.

CONCLUSION

Our findings highlight a potential mechanism of WFA that repairs neurons by modulating the sphingolipid signaling pathway within the microbiota-gut-brain axis.

Lack of significant ganglioside changes in Slc17a5 heterozygous mice: Relevance to FSASD and Parkinson's disease

Large population-based studies of Parkinson's disease (PD) have identified susceptibility genes, including SLC17A5. Biallelic mutations in SLC17A5, encoding the lysosomal sialic acid transporter sialin, cause the rare neurodegenerative disease, free sialic acid storage disorder (FSASD). To explore a potential biochemical link between FSASD and PD, we investigated ganglioside concentrations in a novel mouse model harboring the Slc17a5 p.Arg39Cys (p.R39C) variant. Our analysis revealed no significant alterations in ganglioside concentrations in heterozygous p.R39C mice, warranting further studies into other potential links between PD and sialin defects.

Comparison of visual interpretation of [I-123] FP-CIT SPECT scans versus reference-based quantitative analysis utilizing a Japanese normal database

OBJECTIVE

Dopamine transporter single-photon emission computed tomography (DAT-SPECT) plays an important role in diagnosing parkinsonism. Recently, a reference-based quantitative analysis utilizing a Japanese normal database for DAT-SPECT was developed. This study aimed to investigate the frequency and trends of cases wherein the analysis- and physician-based diagnoses diverged.

METHODS

Two physicians performed an interpretation task twice on 195 DAT-SPECT scans. After assessing intra- and intertester agreements, disagreements were resolved by consensus. For the reference-based quantitative analysis, the calibrated specific binding ratio (cSBR), calibrated asymmetry index (cAI), and Z-scores were measured. Images were grouped according to physician consensus and the negative-positive difference from thresholds (Z-score of less than -2.0 and/or cAI of more than 12.22) as follows: group 1 (physician, normal; quantitative analysis, normal; n  = 70), group 2 (abnormal; normal; n  = 4), group 3 (normal; abnormal; n  = 31), and group 4 (abnormal; abnormal; n  = 90).

RESULTS

Median cSBRs and Z-scores decreased in order from group 1 to group 4. Median cAI values increased in the order of groups 1, 3, 2, and 4. Significant differences were observed between groups 1 and 2 for cSBRs and cAIs; groups 2 and 3 for Z-scores; groups 2 and 4 for cSBRs and Z-scores; and groups 1 and 3, 1 and 4, and 3 and 4 for all parameters (Kruskal-Wallis and Steel-Dwass tests).

CONCLUSION

In approximately 18% of cases, the visual interpretation of physicians diverged from the reference-based quantitative analysis based on a Japanese normal database. It is crucial to appropriately utilize DAT-SPECT reference-based quantitative analysis as a diagnostic aid.

Dysregulated angiogenin and related pathways in the ventral midbrain of "redhead" mice with MC1R disruption

A relationship between the melanoma-related pigmentation gene melanocortin 1 receptor (MC1R) and Parkinson's disease (PD) has been previously suggested. The present study aims to investigate the gene expression pattern in the ventral midbrain (VMB) of MC1R extension (MC1Re/e) mice to provide insights into the underlying mechanism of dopaminergic neuron loss in these mice. RNA sequencing (RNA-seq) was conducted on VMB tissues from MC1Re/e mice and their wild-type (WT) C57BL/6J littermates. Gene expression levels and pathway activity were assessed using differential gene expression analysis, Gene ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and Gene Set Enrichment Analysis (GSEA). To validate the RNA-seq results, real-time quantitative polymerase chain reaction (RT-qPCR), Western blotting (WB), and ELISA were performed. Our analyses found significant transcriptomic differences in the VMB between MC1Re/e mice and WT controls. Several immune response-related pathways were identified to be downregulated in the MC1Re/e group. Angiogenin (ANG) was implicated in several of the enriched pathways in MC1Re/e mice. Furthermore, Ang was found to be significantly downregulated in the VMB of MC1Re/e mice, which was confirmed at both mRNA and protein levels. There was no significant difference in Ang protein levels in the serum of MC1Re/e and WT mice. Our results suggest a differential gene expression pattern in the VMB as a result of MC1R mutation. Notably, lower Ang expression may be involved in the neuronal loss observed in the VMB of the MC1Re/e mice.NEW & NOTEWORTHY Our study identifies reduced angiogenin (Ang) expression in the ventral midbrain (VMB) of MC1Re/e mice, validated through RNA-seq, RT-qPCR, and Western blot. This CNS-specific downregulation suggests localized regulatory mechanisms linked to neuroprotection and Parkinson's disease (PD) pathogenesis. Ang's role in neurodegeneration, angiogenesis, and oxidative stress responses highlights its therapeutic potential in PD. These findings provide critical insights into Ang's CNS-specific function and underscore the importance of further research into its mechanistic role in PD.

Exploring the dynamic pathogenesis of Parkinson's disease by case-control and longitudinal blood transcriptome analyses

The pathogenesis of Parkinson's disease (PD) was recently hypothesized to change along with the disease course. Given the fact that transcriptional changes in blood can provide insightful clues for PD pathogenesis, we performed case-control and longitudinal whole blood transcriptome analyses to identify the signature genes underlying the hypothesized dynamic pathogenesis of PD. In the case-control study, we compared the gene expression patterns in healthy control (N = 189), prodromal (N = 58) and de novo idiopathic PD subjects (N = 390). The results showed that the prodromal subjects were at the tipping-point stage, which is characterized by the abnormal expression patterns of 414 genes associated with oxygen transport and reactive oxygen species metabolic process. We next performed a longitudinal transcriptome analysis on 255 PD patients from the baseline to the third year, and identified 203 genes related to immune and inflammatory responses during disease progression. These findings not just offer deeper insights into the dynamic pathogenesis of PD, but also help to find potential drugs to prevent the early neurodegeneration process.

The thermodynamic hypothesis of protein aggregation

Protein misfolding and aggregation drive some of the most prevalent and lethal disorders of our time, including Alzheimer's and Parkinson's diseases, now affecting tens of millions of people worldwide. The complexity of these diseases, which are often multifactorial and related to age and lifestyle, has made it challenging to identify the causes of the accumulation of aberrant protein deposits. An insight into the origins of these deposits comes from reports of a widespread presence of protein aggregates even under normal cellular conditions. This observation is best accounted for by the thermodynamic hypothesis of protein aggregation. According to this hypothesis, many proteins are expressed at levels close to their supersaturation limits, so that their native states are metastable against aggregation. Here we integrate the evidence behind this hypothesis and outline actionable therapeutic strategies that could halt protein aggregation at its source.

Neurodegeneration models in Parkinson's disease: cellular and molecular paths to neuron death

Parkinson's disease (PD) is a progressive neurodegenerative disorder that affects dopaminergic neurons in the substantia nigra pars compacta. It is a complex disease that is strongly influenced by environmental and genetic factors. While the exact causes of PD are not well understood, research on the effects of toxic substances that induce neuronal death has shed some light on the etiology of the disease. In addition, studies have implicated protein aggregation and impaired mitochondrial, endoplasmic reticulum (ER), proteasome, and/or lysosomal function in the pathogenesis of PD. This review focuses on the alterations in intraneuronal organelles and the role of toxic agents that lead to organelle damage and neurodegeneration that characterize PD. We describe in vivo and in vitro models that have been used to elucidate the factors that lead to the death of dopaminergic neurons and summarize the molecular mechanisms that may underlie the changes that promote neurodegeneration. A deeper understanding of the mechanisms of neuronal death may help us to develop new therapies and interventions to delay or prevent the progression of PD.

Alpha-Synuclein drives NURR1 and NLRP3 Inflammasome dysregulation in Parkinson's disease: From pathogenesis to potential therapeutic strategies

Parkinson's disease (PD), a progressive neurodegenerative disorder, is characterized by the loss of dopaminergic neurons and pathological aggregation of α-synuclein (α-Syn). Emerging evidence highlights the interplay between genetic susceptibility, neuroinflammation, and transcriptional dysregulation in driving PD pathogenesis. This review brings together the latest information on three important players: α-Syn, the transcription factor Orphan nuclear receptor (NURR1), and the NOD-like receptor 3 (NLRP3) inflammasome. Pathogenic α-syn aggregates cause damage to neurons by disrupting mitochondria and lysosomes and spreading in a way similar to prion proteins. They also turn on the NLRP3 inflammasome, which is a key player in neuroinflammation. NLRP3-driven release of pro-inflammatory cytokines exacerbates neurodegeneration and creates a self-sustaining inflammatory milieu. Meanwhile, reduced NURR1 activity, a pivotal modulator of dopaminergic neuron survival and development, exposes neurons to oxidative stress, neuroinflammation, and α-Syn toxicity, hence exacerbating disease progression. So, targeting this trio exhibits transformative potential against PD pathogenesis.

RIPK1: A Promising Target for Intervention Neuroinflammation

Necroptosis is a novel mode of cell death that differs from traditional apoptosis, characterized by distinct molecular mechanisms and physiopathological features. Recent research has increasingly underscored the pivotal role of necroptosis in various neurological diseases, including stroke, Alzheimer's disease and multiple sclerosis. A defining hallmark of these conditions is neuroinflammation, a complex inflammatory response that critically influences neuronal survival. This review provides a comprehensive analysis of the mechanistic underpinnings of necroptosis and its intricate interplay with neuroinflammation, exploring the interrelationship between the two processes and their impact on neurological disorders. In addition, we discuss potential therapeutic strategies that target the intervention of necroptosis and neuroinflammation, offering novel avenues for intervention. By deepening our understanding of these interconnected processes, the development of more effective treatments approaches holds significant promise for improving patient outcomes in neurological disorders.

Approaches for treating neuropsychiatric symptoms in Parkinson's disease: a narrative review

Neuropsychiatric symptoms in Parkinson's disease (PD) are highly prevalent and profoundly disabling, often emerging even before the onset of motor symptoms. As the disease progresses, these symptoms usually become increasingly impairing and are now recognized as having the greatest impact on quality of life not only for patients but also for caregivers. In recent years, there have been significant advances in the diagnosis and management of neuropsychiatric symptoms. However, there are still substantial gaps in therapeutic approaches and algorithms, with limited pharmacological and nonpharmacological treatment options currently available. One of the main reasons for this is the complex molecular and neural bases of these symptoms, which involve both dopaminergic and nondopaminergic neurotransmission systems and extend far beyond the nigrostriatal pathway. As a result, the drugs currently recommended for treating neuropsychiatric symptoms in PD are few and supported by limited evidence. In this context, the experience of the treating neurologist remains critical in selecting the most appropriate individualized therapy. The aim of this paper is to review the available therapeutic options and provide an overview of current research efforts, particularly those focusing on pharmacological treatments.

Subregion-specific suppression of dopamine D1 receptor expression prevents L-DOPA-induced dyskinesia in a mouse model of Parkinson's disease

L-DOPA-induced dyskinesia (LID) is a debilitating motor complication that develops following prolonged L-DOPA therapy in patients with Parkinson's disease (PD). Aberrant activation of dopamine D1 receptor (DRD1) signaling in D1-type/direct pathway medium spiny neurons (MSNs) of the striatum plays a critical role in the pathophysiology of LID. We previously characterized DRD1 signaling in seven striatal subregions and found that upregulation of DRD1 signaling in the intermediate/caudal part (IC) is associated with LID in a mouse model of PD. Here, we investigated whether DRD1 expression in the IC plays a causal role in LID development. Using an adeno-associated virus (AAV) expressing a short hairpin RNA against Drd1 (AAV-shDrd1), we selectively knocked down DRD1 expression in the IC of male mice. In unilateral 6-hydroxydopamine-lesioned mice, DRD1 knockdown in the IC significantly attenuated LID after acute and chronic L-DOPA treatment. In contrast, knockdown in either the rostral or intermediate/rostral part, previously identified as the LID-unrelated subregion, did not affect LID. These findings highlight the essential role of DRD1 and its signaling in the IC in LID development, providing valuable insights for developing novel therapeutic approaches.

The neuroprotective effects of N-acetylcysteine in psychiatric and neurodegenerative disorders: From modulation of glutamatergic transmission to restoration of synaptic plasticity

N-acetylcysteine (NAC) is an effective pleiotropic drug with a strong safety profile. It is predominantly used as a mucolytic agent and in the treatment of paracetamol overdose. However, extensive research in the last decade has shown the prominent efficacy of NAC in many neuropsychiatric and neurodegenerative disorders. NAC acts through multiple mechanisms; primarily, it releases cysteine and modulates glutamatergic and monoaminergic transmission. Further, it restores glutathione levels, promotes oxidative balance, reverses decreased synaptic plasticity, reduces neuroinflammation and mitochondrial dysfunction, and provides neurotrophic support. Additionally, it regulates one-carbon metabolism pathways, leading to the production of key metabolites. In this review, we will be discussing in-depth mechanisms of action of NAC and its promising ability to reverse neuropathological changes, particularly cognitive deficits, and associated plasticity changes in various psychiatric and neurodegenerative diseases, including depression, bipolar disorders, schizophrenia, Alzheimer's disease, Huntington's disease, traumatic brain injury, aging. Overall, several preclinical studies and clinical trials have demonstrated the efficacy of NAC in reversing regressive plasticity, cognitive deficits, and associated changes in the brain. NAC remains among the strongest candidates with a high safety profile for managing several types of neurological disorders.

The gut-brain axis in early Parkinson's disease: from prodrome to prevention

Parkinson's disease is the second most common neurodegenerative disorder and fastest growing neurological condition worldwide, yet its etiology and progression remain poorly understood. This disorder is characterized pathologically by the prion-like spread of misfolded neuronal alpha-synuclein proteins in specific brain regions leading to Lewy body formation, neurodegeneration, and progressive neurological impairment. It is unclear what triggers Parkinson's and where α-synuclein protein aggregation begins, although proposed induction sites include the olfactory bulb and dorsal motor nucleus of the vagus nerve. Within the last 20 years, there has been increasing evidence that Parkinson's could be triggered by early microbiome changes and α-synuclein accumulation in the gastrointestinal system. Gut microbiota dysbiosis that alters gastrointestinal motility, permeability, and inflammation could enable prion-like spread of α-synuclein from the gut-to-brain via the enteric nervous system. Individuals with isolated rapid eye movement sleep behavior disorder have a high likelihood of developing Parkinson's and might represent a prodromal 'gut-first' subtype of the condition. The gut-first model of Parkinson's offers novel gut-based therapeutic avenues, such as anti-, pre-, and pro-biotic preparations and fecal microbiota transplants. Crucially, gut-based interventions offer an avenue to treat Parkinson's at early prodromal stages with the aim of mitigating evolution to clinically recognizable Parkinson's disease characterized by motor impairment.

Trehalose-releasing nanogels reduce α-synuclein-induced Lewy body-like inclusions in primary mouse hippocampal neurons

Parkinson's disease (PD) is the second most prevalent age-related neurodegenerative disorder, clinically characterized by both motor and non-motor symptoms. A key hallmark of PD is the accumulation of misfolded α-synuclein, which aggregates to Lewy bodies (LB) formed inside neurons. Trehalose, a disaccharide that induces autophagy, has been demonstrated to reduce α-synuclein aggregation in vivo. However, the enzyme trehalase rapidly degrades free trehalose, and its hydrophilicity causes poor penetration through the cell membrane. Thus, advanced trehalose delivery strategies are urgently needed. Herein, we investigated the effects of trehalose-bearing nanogels for reducing α-synuclein protein-induced perinuclear LB-like pathology in primary mouse hippocampal neurons. The study compares the effects of trehalose-releasing nanogel (TR) and trehalose-non releasing nanogel (TNR). The results showed that TR, but not TNR, nor free trehalose reduced LB-like inclusions in primary hippocampal neurons. The neuroprotective effects of TR may result from the synergistic effects of direct limitation of α-synuclein aggregates formation and trehalose release-induced autophagy promoting aggregates clearance. Overall, enhancing trehalose delivery with nanogels that can sustainably release trehalose could be worth further investigation as a new potential option for reducing α-synuclein aggregation in neurons affected by neurodegenerative diseases.

Autophagy Process in Parkinson's Disease Depends on Mutations in the GBA1 and LRRK2 Genes

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by the loss of dopaminergic neurons and abnormal aggregation of the alpha-synuclein protein. Disruption of the autophagy-lysosomal pathway is closely associated with PD pathogenesis. Here, using western-blot analysis we assessed the level of autophagy-related proteins, including phosphorylated mTOR (p-mTOR), phosphorylated RPS6 (p-RPS6), beclin-1 (BECN1), LC3B, p62, and cathepsin D (CTSD) in macrophages derived from peripheral blood mononuclear cells (PBMC-derived macrophages) of GBA1-PD (p.N370S/N, p.L444P/N), LRRK2-PD (p.G2019S/N), idiopathic PD (iPD) patients, and healthy controls. Our findings revealed mutation-specific disruptions in autophagy pathways among PD patients. In p.N370S-GBA1-PD, PBMC-derived macrophages exhibited elevated levels of p-RPS6, BECN1, LC3B-II and decreased mature form of CTSD levels suggesting more active mTOR-dependent autophagy initiation alongside potential autophagosome accumulation that may lead to downregulation of lysosomal degradation. p.L444P-GBA1-PD PBMC-derived macrophages showed increased levels of p-RPS6 and BECN1, coupled with decreased p62 levels and stable mature form of CTSD and LC3B-II, indicative of enhanced autophagy flux driven by mTOR activity without evident lysosomal dysfunction. In p.G2019S-LRRK2-PD patients, PBMC-derived macrophages demonstrated elevated p-RPS6, LC3B-II, and mature CTSD levels, alongside reduced p62 levels. These changes suggest higher basal autophagosome abundance in steady-state autophagy and turnover, potentially driven by lysosomal alterations rather than direct mTOR dysregulation. These mutation-dependent differences highlight distinct autophagy dynamics in GBA1-PD and LRRK2-PD, underscoring the critical role of genetic mutations in modulating PD pathogenesis. Our results emphasize the necessity for subtype-specific therapeutic strategies targeting autophagy and other mTOR-regulated pathways to address the heterogeneity of PD mechanisms.

Sex-specific progression of Parkinson's disease: A longitudinal mixed-models analysis

BackgroundDespite its relevance, the clinical progression of motor- and non-motor symptoms associated with Parkinson's disease (PD) is poorly described and understood, particularly in relation to sex-specific differences in clinical progression.ObjectiveIdentification of differential aspects in disease progression in men and women with PD.MethodsLinear mixed-model analyses of 802 people with typical PD from the Luxembourg Parkinson's study's prospective cohort (median time of follow-up = three years). We estimated the effect of time and its moderation by sex (alpha ≤ 0.05), including confidence intervals, for the following outcomes: MDS-UPDRS I-IV, Starkstein Apathy Scale, Beck Depression Inventory, Montreal Cognitive Assessment (MoCA), Sniffin' sticks, bodily discomfort, rapid eye movement sleep behavior disorder questionnaire, PD Sleep Scale (PDSS), Munich Dysphagia Test-PD, Functional Mobility Composite Score, and the MDS-based tremor and postural instability and gait disturbances scale. In addition, the marginal means illustrated the symptoms' trajectories in men and women. Men and women had similar age.ResultsOverall, we observed a slower progression (interaction effect) in women compared to men, especially for MoCA (-0.159, 95%CI [-0.272, -0.046], p = 0.006), PDSS (-0.716, 95%CI [-1.229, -0.203], p = 0.006), PIGD (0.133, 95%CI [0.025 0.241], p = 0.016), and MDS-UPDRS II (0.346, 95%CI [0.120, 0.572], p = 0.003). The finding for MDS-UPDRS II was significant (FWER of 5%) after adjustment for multiple comparisons (Bonferroni-Holm).ConclusionsNext to the further exploration of sex-specific progression, interventions, proactive monitoring and communication strategies tailored to the symptoms progression and needs of men and women need to be developed.

The age-dependent neuroglial interaction with peripheral immune cells in coronavirus-induced neuroinflammation with a special emphasis on COVID-19

Neurodegenerative diseases are chronic progressive disorders that impair memory, cognition, and motor functions, leading to conditions such as dementia, muscle weakness, and speech difficulties. Aging disrupts the stringent balance between pro- and anti-inflammatory cytokines, increasing neuroinflammation, which contributes to neurodegenerative diseases. The aging brain is particularly vulnerable to infections due to a weakened and compromised immune response and impaired integrity of the blood-brain barrier, allowing pathogens like viruses to trigger neurodegeneration. Coronaviruses have been linked to both acute and long-term neurological complications, including cognitive impairments, psychiatric disorders, and neuroinflammation. The virus can induce a cytokine storm, damaging the central nervous system (CNS) and worsening existing neurological conditions. Though its exact mechanism of neuroinvasion remains elusive, evidence suggests it disrupts the blood-brain barrier and triggers immune dysregulation, leading to persistent neurological sequelae in elderly individuals. This review aims to understand the interaction between the peripheral immune system and CNS glial cells in aged individuals, which is imperative in addressing coronavirus-induced neuroinflammation and concomitant neurodegeneration.

ZSCAN21 mediates the pathogenic transcriptional induction of α-synuclein in cellular and animal models of Parkinson's disease

The expression level of α-synuclein is thought to play a crucial role in the pathogenesis of Parkinson's disease. However, little is known about the molecular mechanisms regulating the transcription of its gene, SNCA, particularly in the context of the disease. The transcription factor ZSCAN21 has been shown to act on SNCA, but whether ZSCAN21 is actually involved in the induction of SNCA transcription in Parkinson's disease is unknown. To address this question, we used the MPTP mouse model and LUHMES-derived dopaminergic neuronal spheroids, subjected to Parkinson's disease-related neurotoxins and mutations. We show that MPP+-treated spheroids recapitulate the main features of α-synuclein pathology and that MPP+-triggered transcriptional induction of SNCA is associated with ZSCAN21 stabilisation. Importantly, knock-down of ZSCAN21 prevents both the MPP+-triggered increase in α-synuclein mRNA and pre-mRNA levels in LUHMES-derived spheroids and the death of dopaminergic neurons in the substantia nigra of MPTP-treated mice. These effects are recapitulated by knockdown of TRIM17, a ZSCAN21 stabiliser which prevents its ubiquitination and degradation mediated by TRIM41. Moreover, reducing the interaction between ZSCAN21 and TRIM41, either by inserting Parkinson's disease-associated mutations into the TRIM41 gene or by preventing SUMOylation of ZSCAN21, results in both stabilisation of ZSCAN21 and induction of SNCA. Taken together, our data strongly suggest that ZSCAN21 is a crucial transcription factor for pathogenic α-synuclein expression and neurodegeneration in Parkinson's disease, pointing to its regulators, TRIM17 and TRIM41, as original therapeutic targets for a neuroprotective treatment of Parkinson's disease.

Reliability and validity of in-home tele-neuropsychological testing in patients with Parkinson's disease: A randomized trial

OBJECTIVE

To assess the reliability and diagnostic validity of in-home tele-neuropsychological testing (in-home tele-npt) in individuals with Parkinson's disease (PD).

METHOD

We randomized 79 individuals with PD to in-person npt or in-home tele-npt at Baseline, and again to the same or crossover group for Week 4 testing. We assessed group differences in mean test scores using ANOVAs with Dunnett's t-tests. Test-retest reliability was assessed using intraclass correlation coefficients and Pearson correlations and compared across groups using 95% confidence intervals and z-tests with Fisher's z transformations. We compared the percentage of participants exceeding each test's standardized regression-based index across groups. We examined diagnostic validity by comparing group differences in cognitive classifications using Pearson's Chi-square test and Fisher's Exact test.

RESULTS

For most tests, the mean scores between in-home tele-npt and in-person npt were not significantly different. In-home tele-npt had weaker Baseline processing speed scores. The test-retest reliability was similar between the repeated tele-npt and repeated in-person npt groups in most tests. The crossover groups had weaker test-retest reliability in processing speed, verbal fluency, and memory tests. The percentage of significant change scores varied between groups and across tests. The percentage of participants classified as cognitively impaired, and the agreement of cognitive classification between testing sessions, were not significantly different between groups.

CONCLUSIONS

With few exceptions, in-home tele-npt and in-person tele-npt yield similar scores. Test-retest reliability is better when the testing paradigm is held constant. There are no significant differences in cognitive diagnostic classification rates between testing paradigms in individuals with PD.

The gut microbiota and aging: interactions, implications, and interventions

The human microbiota, a complex ecosystem of microorganisms inhabiting various body sites, particularly the gut, plays a crucial role in maintaining health and influencing disease susceptibility. Dysbiosis, characterized by alterations in microbial composition and diversity, has been implicated in numerous diseases, including those associated with aging. This review examines the complex relationship between gut microbiota and aging, highlighting the age-associated gut microbiota alterations, the factors contributing to these changes, the links between microbiota and age-related diseases, and the potential of interventions targeting the microbiome to extend lifespan and improve health outcomes in the elderly. Further research is needed to unravel the intricate mechanisms underlying the interplay between the microbiome and aging, paving the way for innovative strategies to promote healthy aging.

Effects and mechanisms of acupuncture for PIGD-subtype Parkinson's disease via integration of fMRI and gut microbiota-metabolomics analysis: protocol for a prospective randomized controlled trial

Introduction

Parkinson's disease (PD) can be categorized into various subtypes based on the primary symptoms associated with motor dysfunction. One subtype, known as postural instability and gait difficulty (PIGD), is characterized by severe clinical symptoms, an increased risk of walking difficulties and falls, and a poorer prognosis compared to other subtypes. This condition imposes a significant burden on patients, their families, and the healthcare system. Recently, acupuncture, a practice rooted in traditional Chinese medicine, has gained attention for its potential to influence neurophysiological pathways and enhance the overall brain function in individuals with PD. This randomized controlled study aimed to evaluate the clinical effectiveness of acupuncture in patients with the PIGD subtype of PD and to investigate the preliminary exploration of mechanisms of acupuncture by analyzing intestinal microbiota and metabolomics, thereby providing deeper insights into its impact on patients.

Methods

This randomized controlled trial will involve 64 patients diagnosed with the PIGD subtype of PD. Participants in both groups will undergo three acupuncture sessions weekly for a duration of 4 weeks, followed by an 8-week follow-up period. The primary outcome measure will be the Unified Parkinson's Disease Rating Scale III. Secondary outcomes will include the Berg Balance Scale (BBS), wearable gait analysis, and functional magnetic resonance imaging (fMRI). Additionally, serum and stool samples will be collected for 16S ribosomal RNA sequencing, and liquid chromatography coupled with tandem mass spectrometry analysis (LC-MS/MS) will be employed to elucidate theunderlying mechanisms. This trial has been reviewed and approved by the Medical Ethics Committee of Zhejiang Hospital (Approval no. 2023-15 K). Participation in this study will require written informed consent from all patients. The findings of this study will be published in a peer-reviewed journal, and there will be no restrictions on publication.

Discussion

In this study, we integrate traditional assessment scales with fMRI to demonstrate the therapeutic effects of acupuncture. We will also analyze the modulation of gut microbiota and serum metabolome to explore the underlying neural mechanisms. Our results will provide a foundation for future studies in this area.

Clinical trial registration

https://www.chictr.org.cn, identifier ChiCTR2300071703.

SARM1: a key multifaceted component in immunoregulation, inflammation and neurodegeneration

The downstream signaling pathways of TLR activation involve a family of adaptor proteins, including MYD88, TIRAP, TRIF, TRAM, and SARM1. The first four proteins stimulate inflammatory and antiviral responses, playing crucial roles in innate immunity against various pathogens. In contrast, SARM1 promotes immunity to microorganisms in invertebrate animals independently of TLRs, and negatively regulates inflammatory responses in metazoan organisms. SARM1 inhibits TRIF, reduces the activation of various inflammasomes, and induces mitochondrial damage and cell death to eliminate hyperactivated cells. This regulation is essential to ensure timely control of immune responses and to prevent excessive inflammation. Recently, it was discovered that SARM1 can hydrolyze NAD, a critical component of cellular metabolism. The reduction of NAD levels by SARM1 is linked to the progression of Wallerian degeneration following neuronal injury and may also play a role in the immunoregulation of lymphoid and myeloid cells. Since SARM1 can be pharmacologically modulated, it presents promising opportunities for developing treatments for inflammatory and neurodegenerative diseases.

Dementia with Lewy bodies and Parkinson disease dementia - the same or different and is it important?

Biological definitions of neurological diseases are now becoming a reality, although still in the research phase. This development will recategorize neurological diseases, providing objective diagnostics and the promise of therapeutics that target biological mechanisms - similar to the strategy that has proven successful in tumours and other conditions. In this Perspective article, we discuss this development for dementias with dominant Lewy pathology, as the availability of biological assays for this pathology has sparked new interest in a single disease diagnosis for all individuals positive for α-synuclein. On the basis of current evidence, we argue that an α-synuclein assay alone is unlikely to be a specific criterion for a spectrum of clinical syndromes with Lewy pathology or a definitive diagnostic marker for Lewy body dementia. We advocate that one biological assay will not reflect the complex spatiotemporal features of brain pathology. Diverse sequential mechanisms underpin the highly heterogeneous phenotypes and clinicopathological processes of Lewy body dementias. Disease modification, if possible, will be most effective when it targets the early underlying mechanisms, especially those leading to aggressive phenotypes.

Inhibition of SOD1 trimerization is a novel drug target for ALS disease

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that begins with motor neuron death in the spinal cord and cerebral cortex, ultimately resulting in death from respiratory distress (breathing failure). About 90% of ALS cases are sporadic, and 10% of ALS cases are of the inherited type with a genetic cause. About 150 different gene mutations have been reported so far. SOD1 is a well-identified gene associated with ALS. Indeed, SOD1 aggregation has been reported in ALS patients, but the mechanism of SOD1 aggregation remains unclear. Our previous work showed that inhibiting SOD1 aggregation with a hit compound (PRG-A-01) could reduce the SOD1-induced cytotoxicity and extend the lifespan of ALS mouse model (SOD1G93A-Tg). However, the low bioavailability and rapid degradation of the compound in vivo necessitates the development of a more effective candidate. We generated different derivatives and finally obtained the most potential drug candidate, PRG-A-04.

METHODS

Neuronal cell lines were transfected with the mutant SOD1 expression vector and incubated with PRG-A-04. SOD1 aggregation was examined by SOD1 oligomerization assay, immunofluorescence and dot blot assay. The interaction between GST-conjugated SOD1 recombinant proteins and PRG-A-04 was identified using LC-MS/MS and GST pull-down assay. To check the in vivo therapeutic effect of PRG-A-04, SOD1G93A-Tg mice were injected with PRG-A-04; then behavioral test, histological analysis and microarray were performed.

RESULTS

PRG-A-04 demonstrated favorable pharmacokinetics including high bioavailability and significant blood-brain barrier penetration. Indeed, oral administration of PRG-A-04 in ALS mouse model inhibited the aggregation of SOD1 in the spinal cord, protected against neuronal loss, and extended the lifespan of ALS mice by up to 3 weeks. In vitro, PRG-A-04 selectively bound to the mutant form of SOD1, but not the wild type, and efficiently inhibited the aggregation caused by SOD1-G147P (a SOD1 trimer stabilizer).

CONCLUSIONS

Our findings underscore the potential of targeting trimeric SOD1 in ALS treatment, positioning PRG-A-04 as a strong drug candidate for both familial and sporadic ALS.

Mechanical Forces Guide Axon Growth through the Nigrostriatal Pathway in an Organotypic Model

Reconstructing the nigrostriatal pathway is one of the major challenges in cell replacement therapies for Parkinson's disease due to the lack of enabling technologies capable of guiding the reinnervation of dopaminergic precursors transplanted into the substantia nigra toward the striatum. This paper examines nano-pulling, as a technology to enable the remote manipulation of axonal growth. Specifically, an organotypic model consisting of co-cultures of the substantia nigra and the striatum is developed to demonstrate that when cortical neural progenitors are transplanted into the substantia nigra, nano-pulling can guide and enhance the elongation of neural projections toward the striatum. To provide additional evidence, induced pluripotent stem cell-derived dopaminergic progenitor neurospheres are generated and it is shown that nano-pulling can induce guided growth and promote the maturation of their neural processes. Altogether, this study demonstrates the potential of nano-pulling as an emerging technique to promote directed reinnervation within the central nervous system.

Lipid nanoparticle (LNP) mediated mRNA delivery in neurodegenerative diseases

Neurodegenerative diseases (NDD) are characterized by the progressive loss of neurons and the impairment of cellular functions. Messenger RNA (mRNA) has emerged as a promising therapy for treating NDD, as it can encode missing or dysfunctional proteins and anti-inflammatory cytokines or neuroprotective proteins to halt the progression of these diseases. However, effective mRNA delivery to the central nervous system (CNS) remains a significant challenge due to the limited penetration of the blood-brain barrier (BBB). Lipid nanoparticles (LNPs) offer an efficient solution by encapsulating and protecting mRNA, facilitating transfection and intracellular delivery. This review discusses the pathophysiological mechanisms of neurological disorders, including Parkinson's disease (PD), Alzheimer's disease (AD), multiple sclerosis (MS), Huntington's disease (HD), ischemic stroke, spinal cord injury, and Friedreich's ataxia. Additionally, it explores the potential of LNP-mediated mRNA delivery as a therapeutic strategy for these diseases. Various approaches to overcoming BBB-related challenges and enhancing the delivery and efficacy of mRNA-LNPs are discussed, including non-invasive methods with strong potential for clinical translation. With advancements in artificial intelligence (AI)-guided mRNA and LNP design, targeted delivery, gene editing, and CAR-T cell therapy, mRNA-LNPs could significantly transform the treatment landscape for NDD, paving the way for future clinical applications.

Macrophages in the dCLN are required for α-synuclein proteostasis in A53T PD model mice

The metabolic disorder of α-synuclein in the central nervous system (CNS) is a key factor leading to excessive accumulation of aggregated α-synuclein and ultimately to the formation of Lewy bodies, which is one of the main pathological features of Parkinson's disease (PD). Although the mechanism underlying this process remains elusive, systemic metabolic abnormalities have been demonstrated to affect the progression of neurodegenerative diseases. The recent discovery of meningeal lymphatics provides a specific route for connection between the CNS and the periphery. As draining lymph nodes for CSF, the deep cervical lymph nodes (dCLN) are important for maintaining CNS homeostasis. However, whether and how macrophages in the peripheral dCLN system are involved in the α-synuclein homeostasis is largely unknown. Here, we report that macrophages in the deep cervical lymph node (dCLN) are required for maintaining α-synuclein proteostasis in an LRRK2 and lysosome-dependent pathway in A53T PD model mice, providing a fresh perspective on understanding the pathology of PD.

Machine learning-based meta-analysis reveals gut microbiome alterations associated with Parkinson's disease

There is strong interest in using the gut microbiome for Parkinson's disease (PD) diagnosis and treatment. However, a consensus on PD-associated microbiome features and a multi-study assessment of their diagnostic value is lacking. Here, we present a machine learning meta-analysis of PD microbiome studies of unprecedented scale (4489 samples). Within most studies, microbiome-based machine learning models accurately classify PD patients (average AUC 71.9%). However, these models are study-specific and do not generalise well across other studies (average AUC 61%). Training models on multiple datasets improves their generalizability (average LOSO AUC 68%) and disease specificity as assessed against microbiomes from other neurodegenerative diseases. Moreover, meta-analysis of shotgun metagenomes delineates PD-associated microbial pathways potentially contributing to gut health deterioration and favouring the translocation of pathogenic molecules along the gut-brain axis. Strikingly, microbial pathways for solvent and pesticide biotransformation are enriched in PD. These results align with epidemiological evidence that exposure to these molecules increases PD risk and raise the question of whether gut microbes modulate their toxicity. Here, we offer the most comprehensive overview to date about the PD gut microbiome and provide future reference for its diagnostic and functional potential.

Using Single-Cell RNA sequencing with Drosophila, Zebrafish, and mouse models for studying Alzheimer's and Parkinson's disease

Alzheimer's and Parkinson's disease are the most common neurodegenerative diseases, significantly affecting the elderly with no current cure available. With the rapidly aging global population, advancing research on these diseases becomes increasingly critical. Both disorders are often studied using model organisms, which enable researchers to investigate disease phenotypes and their underlying molecular mechanisms. In this review, we critically discuss the strengths and limitations of using Drosophila, zebrafish, and mice as models for Alzheimer's and Parkinson's research. A focus is the application of single-cell RNA sequencing, which has revolutionized the field by providing novel insights into the cellular and transcriptomic landscapes characterizing these diseases. We assess how combining animal disease modeling with high-throughput sequencing and computational approaches has advanced the field of Alzheimer's and Parkinson's disease research. Thereby, we highlight the importance of integrative multidisciplinary approaches to further our understanding of disease mechanisms and thus accelerating the development of successful therapeutic interventions.

Construction and Identification of Inflammation-Related TF-mRNA-miRNA Coexpression Network and Immune Infiltration in Parkinson's Disease

Background: Parkinson's disease (PD) is the second most common neurodegenerative disease worldwide. Inflammation, marked by the infiltration of inflammatory mediators and the proliferation of inflammatory cells, is closely linked to PD. This study aims to identify and validate inflammation-related biomarkers in PD and construct a TF-mRNA-miRNA coexpression network through bioinformatics analysis. Methods: The PD-associated dataset GSE7621 and inflammation-related genes were downloaded from the GEO Database and GeneCards platform to obtain inflammation-related differential expression genes (IRDEGs). The key IRDEGs were generated by PPI network analysis. The gene expression levels of the key IRDEGs were validated by blood samples from PD patients using QPCR analysis. We utilized the ENCODE, hTFtarget, CHEA, miRWALK, and miRDB databases to obtain upstream and downstream molecular network models for constructing the TF-mRNA-miRNA interaction network of the key IRDEGs. Finally, based on CIBERSORT algorithm, the associations between IRDEs and immune cell infiltration were investigated. Results: A total of four key IRDEGs (CXCR4, LEP, SLC18A2, and TAC1) were screened and validated. Through biological function analysis, key-related pathways and coexpression networks of PD were identified. These genes may be closely related to the onset of PD. Additionally, we found that increased CD4 T-cell infiltration might be associated with the occurrence of PD. Conclusions: We identified four potential inflammation-related treatment target and constructed a TF-mRNA-miRNA regulatory network. This information provides an initial basis for understanding the complex PD regulatory mechanisms.

Transforming neurodegenerative disorder care with machine learning: Strategies and applications

Neurodegenerative diseases (NDs), characterized by progressive neuronal degeneration and manifesting in diverse forms such as memory loss and movement disorders, pose significant challenges due to their complex molecular mechanisms and heterogeneous patient presentations. Diagnosis often relies heavily on clinical assessments and neuroimaging, with definitive confirmation frequently requiring post-mortem autopsy. However, the emergence of Artificial Intelligence (AI) and Machine Learning (ML) offers a transformative potential. These technologies can enable the development of non-invasive tools for early diagnosis, biomarker identification, personalized treatment strategies, patient subtyping and stratification, and disease risk prediction. This review aims to provide a starting point for researchers, both with and without clinical backgrounds, who are interested in applying ML to NDs. We will discuss available data resources for key diseases like Alzheimer's and Parkinson's, explore how ML can revolutionize neurodegenerative care, and emphasize the importance of integrating multiple high-dimensional data sources to gain deeper insights and inform effective therapeutic strategies.

Dopamine D2 receptor upregulation in dorsal striatum in the LRRK2-R1441C rat model of early Parkinson's disease revealed by in vivo PET imaging

We conducted PET imaging with [18F]FDOPA and dopamine D2/3 receptor ligand [18F]fallypride in aged transgenic rats carrying human pathogenic LRRK2 R1441C or G2019S mutations. These rats have mild age-dependent deficits in dopamine release restricted to dorsal striatum despite no overt loss of dopamine neurons or dopamine content and demonstrate L-DOPA-responsive movement deficits.LRRK2 mutant rats displayed no deficit in [18F]FDOPA uptake, consistent with intact dopamine synthesis in striatal axons. However, LRRK2-R1441C rats demonstrated greater binding of [18F]fallypride than LRRK2-G2019S or non-transgenic controls, from a regionally selective increase in dorsal striatum. Immunocytochemical labelling post-mortem confirmed a greater density of D2 receptors in LRRK2-R1441C than other genotypes restricted to dorsal striatum, consistent with upregulation of D2-receptors as a compensatory response to the greater dopamine release deficit previously demonstrated in this genotype.These results show that [18F]fallypride PET imaging is sensitive to dysregulation of dopamine signalling in the LRRK2-R1441C rat, revealing upregulation of D2 receptors that parallels observations in human putamen in early sporadic PD. Future studies of candidate therapies could exploit this non-invasive approach to assess treatment efficacy.

Neural and vascular contributions to sensory impairments in a human alpha-synuclein transgenic mouse model of Parkinson's disease

Parkinson's disease (PD) is a complex progressive neurodegenerative disorder involving hallmarks such as α -Synuclein (α Syn) aggregation and dopaminergic dysfunction that affect brain-wide neural activity. Although movement disorders are prominent in PD, sensory impairments also occur relatively early on, mainly in olfactory and, to a lesser extent visual systems. While these deficits have been described mainly at the behavioral and molecular levels, the underlying network-level activity remains poorly understood. Here, we harnessed a human α Syn transgenic mouse model of PD with in vivo functional MRI (fMRI) to map evoked activity in the visual and olfactory pathways, along with pseudo-Continuous Arterial Spin Labeling (pCASL) and c-FOS measurements to disentangle vascular from neuronal effects. Upon stimulation with either odors or flickering lights, we found significant decreases in fMRI responses along both olfactory and visual pathways, in multiple cortical and subcortical sensory areas. Average Cerebral Blood Flow rates were decreased by ∼10% in the α Syn group, while c-FOS levels were reduced by over 50%, suggesting a strong neural driver for the dysfunction, along with more modest vascular contributions. Our study provides insight into brain-level activity in an α Syn-based model, and suggests a novel target for biomarking via quantification of simple sensory evoked responses.

Neuromelanin and selective neuronal vulnerability to Parkinson's disease

Neuromelanin is a unique pigment made by some human catecholamine neurons. These neurons survive with their neuromelanin content for a lifetime but can also be affected by age-related neurodegenerative conditions, as observed using new neuromelanin imaging techniques. The limited quantities of neuromelanin has made understanding its normal biology difficult, but recent rodent and primate models, as well as omics studies, have confirmed its importance for selective neuronal loss in Parkinson's disease (PD). We review the development of neuromelanin in dopamine versus noradrenaline neurons and focus on previously overlooked cellular organelles in neuromelanin formation and function. We discuss the role of neuromelanin in stimulating endogenous α-synuclein misfolding in PD which renders neuromelanin granules vulnerable, and can exacerbates other pathogenic processes.

Computer Vision Technologies in Movement Disorders: A Systematic Review

BACKGROUND

Evaluation of movement disorders primarily relies on phenomenology. Despite refinements in diagnostic criteria, the accuracy remains suboptimal. Such a gap may be bridged by machine learning and video technology, which permit objective, quantitative, non-invasive motor analysis. Markerless automated video-analysis, namely Computer Vision, emerged as best suited for ecologically-valid assessment.

OBJECTIVES

To systematically review the application of Computer Vision for assessment, diagnosis, and monitoring of movement disorders.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we searched Cochrane, Embase, PubMed, and Scopus databases for articles published between 1984 and September 2024. We used the following search strategy: ("video analysis" OR "computer vision") AND ("Parkinson's disease" OR "PD" OR "tremor" OR "dystonia" OR "parkinsonism" OR "progressive supranuclear palsy" OR "PSP" OR "multiple system atrophy" OR "MSA" OR "corticobasal syndrome" OR "CBS" OR "chorea" OR "ballism" OR "myoclonus" OR "Tourette's syndrome").

RESULTS

Out of 1099 identified studies, 61 met inclusion criteria, and 10 additional studies were included based on authors' judgment. Parkinson's disease was the most investigated movement disorder, with gait as the prevalent motor task. OpenPose was the most used pose estimation software. Automated video-analysis consistently achieved diagnostic accuracies exceeding 80% across most movement disorders. For tremor, dystonia severity and tic detection, Computer Vision strongly aligned with accelerometery and clinical assessments.

CONCLUSIONS

Computer Vision holds potential to provide non-invasive quantification of presence and severity of movement disorders. Heterogeneity in video settings, software usage, and definition of standardized guidelines for videorecording are challenges to be addressed for real-word applications.

The cannabinoid receptor 1 mediates exercise-induced improvements of motor skill learning and performance in parkinsonian mouse

The endocannabinoid system (eCBs) modulates corticostriatal circuits through cannabinoid receptor 1 (CB1R). These circuits are crucial for encoding goal-directed and habitual learning behaviors and are implicated in the occurrence and progression of Parkinson's disease (PD). While exercise has been shown to enhance motor performance and reverse learning deficits in PD patients, the underlying molecular mechanisms remain unclear. We hypothesized that a treadmill training program could rescue changes in striatal plasticity and ameliorate early motor and cognitive deficits in mice subjected to an intrastriatal 6-hydroxydopamine injection. Our findings demonstrated that exercise training would improve motor performance and learning abilities in PD mice. Moreover, both immunofluorescence and reverse transcription polymerase chain reaction results suggested that corticostriatal activation decreased CB1R expression in the dorsomedial striatum of PD mice but increased expression in the substantia nigra pars reticulata following treadmill exercise. These results suggest that dysregulated CB1R expression is associated with the pathogenesis of Parkinsonism, highlighting the vital role of the CB1R in corticostriatal pathway functionality enhanced by exercise. Our results suggest the potential benefits of treadmill exercise in alleviating Parkinsonism, providing valuable insights into future potential treating strategies.

High-resolution mapping of substantia nigra in Parkinson's disease using 7 tesla magnetic resonance imaging

Parkinson's disease causes a progressive loss of dopaminergic neurons and iron accumulation in the substantia nigra pars compacta. Using ultra-high field magnetic resonance imaging (MRI) at 7 tesla in 43 Parkinson's patients and 24 healthy controls, we analyzed the voxel-wise pattern of structural disintegration of dopamine neurons with neuromelanin-sensitive MRI, along with assessing iron accumulation using R2* and quantitative susceptibility mapping (QSM). We also explored correlations between these measures and the severity of residual motor symptoms in the on-medication state and other clinical variables. Differences were most notable in the nigrosomes within the pars compacta, with patients showing reduced neuromelanin signals and increased QSM values. Severity and asymmetry of motor symptoms correlated with higher R2* and QSM values in nigrosome N1. Thus, ultra-high field MRI provides high-resolution maps of various aspects of the underlying neurodegenerative process which reflect individual motor impairment in Parkinson's disease.

Oligodendroglia vulnerability in the human dorsal striatum in Parkinson's disease

Oligodendroglia are the responsible cells for myelination in the central nervous system and their involvement in Parkinson's disease (PD) is poorly understood. We performed sn-RNA-seq and image-based spatial transcriptomics of human caudate nucleus and putamen (dorsal striatum) from PD and control brain donors to elucidate the diversity of oligodendroglia and how they are affected by the disease. We profiled a total of ~ 200.000 oligodendroglial nuclei, defining 15 subclasses, from precursor to mature cells, 4 of which are disease-associated. These PD-specific populations are characterized by the overexpression of heat shock proteins, as well as distinct expression signatures related to immune responses, myelination alterations, and disrupted cell signaling pathways. We have also identified impairments in cell communication and oligodendrocyte development, evidenced by changes in neurotransmitter receptors expression and cell adhesion molecules. In addition, we observed significant disruptions in oligodendrocyte development, with aberrant differentiation trajectories and shifts in cell proportions, particularly in the transition from mature oligodendrocytes to disease-associated states. Quantitative immunohistochemical analysis revealed decreased myelin levels in the PD striatum, which correlated with transcriptomic alterations. Furthermore, spatial transcriptomics mapping revealed the distinct localization of disease-associated populations within the striatum, with evidence of impaired myelin integrity. Thus, we uncover oligodendroglia as a critical cell type in PD and a potential new therapeutic target for myelin-based interventions.

Discovery of potential Leonurine-based therapeutic lead MJ210 attenuates Parkinson's disease pathogenesis via NF-κB and MAPK pathways: Mechanistic insights from in vitro and in vivo rotenone models

Parkinson's disease (PD) is a common neurodegenerative disease affecting motor and non-motor functions, with no effective treatment yet discovered. Neuroprotective compounds, both natural and synthetic, show promise but face challenges such as crossing the blood-brain barrier, limited serum stability, and higher toxicity. To tackle these obstacles, we have devised an innovative design strategy inspired by the neuroprotective properties of Leonurine, widely utilized in managing neurological disorders. Through rigorous screening of our compound library, we have identified a potent therapeutic molecule (MJ210) that exhibited remarkable efficacy in bolstering neuroprotection against rotenone-induced PD models, both in vitro and in vivo. Our findings revealed that administering MJ210 significantly increased neuronal survival in the SH-SY5Y model of PD. This was achieved by preventing apoptosis, reducing reactive oxygen species, mitigating mitochondrial dysfunction, and dampening neuroinflammation via ERK1/2-P38-JNK and P65-NFκB signaling pathways. In addition, MJ210 demonstrated remarkable neuroprotective abilities in vivo by significantly enhancing dopamine biosynthesis, alleviating motor dysfunction, improving balance and coordination, and reversing depression in rotenone-induced PD rats, even outperforming L-DOPA, the current gold standard treatment for PD. Therefore, MJ210 emerges as a significantly promising therapeutic candidate for PD, offering the potential for managing both the severity and progression of this disease.