Diagnosis and treatment of Parkinson disease: molecules to medicine

E3 ubiquitin ligase TRIM31 alleviates dopaminergic neurodegeneration by promoting proteasomal degradation of VDAC1 in Parkinson's Disease model

Mitochondrial dysfunction plays a pivotal role in the pathogenesis of Parkinson's disease (PD). As a mitochondrial governor, voltage-dependent anion channel 1 (VDAC1) is critical for cell survival and death signals and implicated in neurodegenerative diseases. However, the mechanisms of VDAC1 regulation are poorly understood and the role of tripartite motif-containing protein 31 (TRIM31), an E3 ubiquitin ligase which is enriched in mitochondria, in PD remains unclear. In this study, we found that TRIM31-/- mice developed age associated motor defects and dopaminergic (DA) neurodegeneration spontaneously. In addition, TRIM31 was markedly reduced both in nigrostriatal region of PD mice induced by MPTP and in SH-SY5Y cells stimulated by MPP+. TRIM31 deficiency significantly aggravated DA neurotoxicity induced by MPTP. Mechanistically, TRIM31 interacted with VDAC1 and catalyzed the K48-linked polyubiquitination to degrade it through its E3 ubiquitin ligase activity. In conclusion, we demonstrated for the first time that TRIM31 served as an important regulator in DA neuronal homeostasis by facilitating VDAC1 degradation through the ubiquitin-proteasome pathway. Our study identified TRIM31 as a novel potential therapeutic target and pharmaceutical intervention to the interaction between TRIM31 and VDAC1 may provide a promising strategy for PD.

Association between increased and decreased gut microbiota abundance and Parkinson's disease: A systematic review and subgroup meta-analysis

OBJECTIVE

The objective of the study was to systematically investigate the association between gut microbiota (GM) abundance and Parkinson's disease (PD).

METHODS

PubMed, Medline, Cochrane Library and other literature datebase platforms were searched for eligible studies in the English-language from conception to March 1, 2024. Studies evaluating the association between GM and PD were included. The results of the included studies were analyzed using a random effects model with calculation of the mean difference (MD) with the 95 % confidence interval to quantify the incidence of differences in abundance of various bacterial families in PD patients. Continuous models were used to analyze the extracted data.

RESULTS

A total of 14 studies with 1045 PD cases and 821 healthy controls were included for data extraction and meta-analysis. All the included studies exhibited reasonable quality. The included studies reported the data on the ratios of 10 families of GM. Of these 10 microbiota families, Bifidobacteriaceae, Ruminococcaceae, Rikenellaceae, Lactobacillaceae, Verrucomicrobiaceae and Christensenellaceae were found to have increased ratios according to the pooled ratios, while Prevotellaceae, Lachnospiraceae, Erysipelotrichaceae and Faecalibacterium were decreased in PD cases.

CONCLUSION

Patients in the PD cohort exhibited distinctive microbiota compositions compared to healthy individuals, with unique differential patterns in gut microbiome abundance at the phylum, family, and genus levels that may be associated wtih PD pathogenesis.

Naringenin: its chemistry and roles in neuroprotection

According to epidemiological research, as the population ages, neurological illnesses are becoming a bigger issue. Despite improvements in the treatment of these diseases, there are still widespread worries about how to find a long-lasting remedy. Several neurological diseases can be successfully treated with natural substances. As a result, current research has been concentrated on finding effective neuroprotective drugs with improved efficacy and fewer side effects. Naringenin is one potential treatment for neurodegenerative diseases. Many citrus fruits, tomatoes, bergamots, and other fruits are rich in naringenin, a flavonoid. This phytochemical is linked to a variety of biological functions. Naringenin has attracted a lot of interest for its ability to exhibit neuroprotection through several mechanisms. In the current article, we present evidence from the literature that naringenin reduces neurotoxicity and oxidative stress in brain tissues. Also, the literatures that are currently accessible shows that naringenin reduces neuroinflammation and other neurological anomalies. Additionally, we found several studies that touted naringenin as a promising anti-amyloidogenic, antidepressant, and neurotrophic treatment option. This review's major goal is to reflect on advancements in knowledge of the molecular processes that underlie naringenin's possible neuroprotective effects. Furthermore, this article also provides highlights of Naringenin with respect to its chemistry and pharmacokinetics.

A PEDOT: PSS/GO fiber microelectrode fabricated by microfluidic spinning for dopamine detection in human serum and PC12 cells

Rapid and accurate in situ determination of dopamine is of great significance in the study of neurological diseases. In this work, poly (3,4-ethylenedioxythiophene): poly (styrenesulfonic acid) (PEDOT: PSS)/graphene oxide (GO) fibers were fabricated by an effective method based on microfluidic wet spinning technology. The composite microfibers with stratified and dense arrangement were continuously prepared by injecting PEDOT: PSS and GO dispersion solutions into a microfluidic chip. PEDOT: PSS/GO fiber microelectrodes with high electrochemical activity and enhanced electrochemical oxidation activity of dopamine were constructed by controlling the structure composition of the microfibers with varying flow rate. The fabricated fiber microelectrode had a low detection limit (4.56 nM) and wide detection range (0.01-8.0 µM) for dopamine detection with excellent stability, repeatability, and reproducibility. In addition, the PEDOT: PSS/GO fiber microelectrode prepared was successfully used for the detection of dopamine in human serum and PC12 cells. The strategy for the fabrication of multi-component fiber microelectrodes is a new and effective approach for monitoring the intercellular neurotransmitter dopamine and has high potential as an implantable neural microelectrode.

Frailty and Parkinson's disease: the role of diabetes mellitus

Parkinson's disease (PD) is a chronic neurodegenerative disease associated with a progressive loss of dopaminergic neurons, clinically characterized by motor and non-motor signs. Frailty is a clinical condition of increased vulnerability and negative health outcomes due to the loss of multiple physiological reserves. Chronic hyperglycemia and insulin resistance, which characterize diabetes mellitus (DM), have been reported to alter dopaminergic activity, increase the risk of PD, and influence the development of frailty. Even though diabetes may facilitate the development of frailty in patients with PD, this relationship is not established and a revision of the current knowledge is necessary. Furthermore, the synergy between DM, PD, and frailty may drive clinical complexity, worse outcomes, and under-representation of these populations in the research. In this review, we aimed to discuss the role of diabetes in the development of frailty among patients with PD. We summarized the clinical characteristics and outcomes of patients with concomitant DM, PD, and frailty. Finally, interventions to prevent frailty in this population are discussed.

PRKN-linked familial Parkinson's disease: cellular and molecular mechanisms of disease-linked variants

Parkinson's disease (PD) is a common and incurable neurodegenerative disorder that arises from the loss of dopaminergic neurons in the substantia nigra and is mainly characterized by progressive loss of motor function. Monogenic familial PD is associated with highly penetrant variants in specific genes, notably the PRKN gene, where homozygous or compound heterozygous loss-of-function variants predominate. PRKN encodes Parkin, an E3 ubiquitin-protein ligase important for protein ubiquitination and mitophagy of damaged mitochondria. Accordingly, Parkin plays a central role in mitochondrial quality control but is itself also subject to a strict protein quality control system that rapidly eliminates certain disease-linked Parkin variants. Here, we summarize the cellular and molecular functions of Parkin, highlighting the various mechanisms by which PRKN gene variants result in loss-of-function. We emphasize the importance of high-throughput assays and computational tools for the clinical classification of PRKN gene variants and how detailed insights into the pathogenic mechanisms of PRKN gene variants may impact the development of personalized therapeutics.

Human neural stem cells promote mitochondrial genesis to alleviate neuronal damage in MPTP-induced cynomolgus monkey models

Currently, there is no effective treatment for Parkinson's disease (PD), and the regenerative treatment of neural stem cells (NSCs) is considered the most promising method. This study aimed to investigate the protective effect and mechanism of NSCs on neurons in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced cynomolgus monkey (Macaca fascicularis) model of PD. We first found that injecting NSCs into the subarachnoid space relieved motor dysfunction in PD cynomolgus monkeys, as well as reduced dopaminergic neuron loss and neuronal damage in the substantia nigra (SN) and striatum. Besides, NSCs decreased 17-estradiol (E2) level, an estrogen, in the cerebrospinal fluid (CSF) of PD cynomolgus monkeys, which shows NSCs may provide neuro-protection by controlling estrogen levels in the CSF. Furthermore, NSCs elevated proliferator-activated receptor gamma coactivator-1 alpha (PGC-1a), mitofusin 2 (MFN2), and optic atrophy 1 (OPA1) expression, three genes mediating mitochondrial biogenesis, in the SN and striatum of PD monkeys. In addition, NSCs suppress reactive oxygen species (ROS) production caused by MPTP, as well as mitochondrial autophagy, therefore preserving dopaminergic neurons. In summary, our findings show that NSCs may preserve dopaminergic and neuronal cells in an MPTP-induced PD cynomolgus monkey model. These protective benefits might be attributed to NSCs' ability of modulating estrogen balance, increasing mitochondrial biogenesis, and limiting oxidative stress and mitochondrial autophagy. These findings add to our understanding of the mechanism of NSC treatment and shed light on further clinical treatment options.

DJ-1 protects cell death from a mitochondrial oxidative stress due to GBA1 deficiency

BACKGROUND

GBA1 mutations are the most common genetic risk factor for development of Parkinson's disease (PD). The loss of catalytic activity in GBA1, as well as the reduction of the GBA1 protein in certain cellular compartment, may increase disease progression. However, the mechanisms underlying cellular dysfunction caused by GBA1 deficiency are still mostly unknown.

OBJECTIVE

In this study, we focus on the genetic interaction between GBA1 deficiency and PD-causing genes, such as DJ-1, in mitochondrial dysfunction.

METHODS

GBA1 knockout (KO) SH-SY5Y cells were used to assess DJ-1 functions against oxidative stress in vitro. The levels of cellular reactive oxygen species were monitored with MitoSOX reagent. The expression of the PARK7 gene was analyzed using the quantitative real-time PCR (qRT-PCR). To understand the mechanism underlying DJ-1 upregulation in GBA1 KO cells, we assess ROS levels, antioxidant protein, and cell viability in GBA1 KO cells with treatment of ROS inhibitor N-acetyl-cysteine or miglustat, which is an inhibitor of glucosylceramide synthase. Dopaminergic degeneration was assessed from Gba1 L444P heterozygous mice mated with Park7 knockout mice.

RESULTS

We find that DJ-1 is significantly upregulated in GBA1 KO cells. Elevated levels of DJ-1 are attributed to the transcriptional expression of PARK7 mRNA, but not the inhibition of DJ-1 protein degradation. Because DJ-1 expression is highly linked to oxidative stress, we observe cellular reactive oxygen species (ROS) in GBA1 KO cells. Moreover, several antioxidant gene expressions and protein levels are increased in GBA1 KO cells. To this end, GBA1 KO cells are more susceptible to H2O2-induced cell death. Importantly, there is a significant reduction in dopaminergic neurons in the midbrain from Gba1 L444P heterozygous mice mated with Park7 knockout mice, followed by mild motor dysfunction.

CONCLUSION

Taken together, our results suggest that DJ-1 upregulation due to GBA1 deficiency has a protective role against oxidative stress. It may be supposed that mutations or malfunctions in the DJ-1 protein may have disadvantages in the survival of dopaminergic neurons in the brains of patients harboring GBA1 mutations.

Efficacy of deep brain stimulation of the subthalamic nucleus versus globus pallidus internus on sensory complaints

Pain control after deep brain stimulation (DBS) in Parkinson's disease (PD) remains unclear. Following six months, subthalamic (STN)-DBS reduced sensory complaints related to parkinsonism and bodily discomfort, increasing central beta-endorphin level. Pallidal GPi-DBS decreased bodily discomfort and beta-endorphin levels. Unexplained pain by other conditions and bodily discomfort were negatively correlated with beta-endorphin levels. Thus, DBS regulates central opioids, and prioritizing STN is important for PD patients with significant sensory complications.

Acupuncture therapy for Parkinson's disease: a case report demonstrating symptomatic improvement without medication

Background

Parkinson's disease (PD) often necessitates immediate medical intervention following diagnosis. In recent years, there has been a noticeable increase in clinical investigations assessing the efficacy of acupuncture in PD, with many studies reporting positive outcomes. Ethical guidelines commonly endorse pharmaceutical therapies for PD, leading ongoing research to combine acupuncture with standard drug-based treatments. At present, there is a conspicuous absence of dedicated clinical research exclusively examining the independent impact of acupuncture on PD treatment.

Case

In a clinical observation, we documented a case involving a 75-year-old male displaying progressive, characteristic PD symptoms, including evident limb tremors, rigidity, bradykinesia, fatigue, and additional non-motor symptoms. The patient received a confirmed diagnosis of PD. Due to the refusal of the patient to take medication, we exclusively administered acupuncture therapy. The outcomes indicated a noteworthy enhancement in the clinical symptoms of the patient solely through acupuncture intervention.

Conclusion

This case affirms that using acupuncture in isolation significantly improved both the motor and non-motor symptoms in the patient. Acupuncture could potentially serve as an alternative therapy for patients who decline or are intolerant to anti-Parkinson drugs. However, further studies are needed to assess its long-term efficacy. This case report obtained approval from the Ethics Committee of the First Affiliated Hospital of Guangzhou University of Chinese Medicine (Ethics number: K-2023-127).

A Phase I, Randomized, SAD, MAD, and PK Study of Risvodetinib in Older Adults and Parkinson's Disease

Background

Pre-clinical studies suggest that c-Abl activation may play an important role in the etiology of Parkinson's disease, making c-Abl an important target to evaluate for potential disease-modification.

Objective

To assess safety, tolerability, and pharmacokinetics of the c-Abl inhibitor risvodetinib (IkT-148009) in healthy subjects and participants with Parkinson's disease.

Methods

Part 1 (single ascending dose (SAD)) and Part 2 (7-day multiple ascending dose (MAD)) studies were in healthy volunteers. Participants were randomized 3 : 1 across 9 SAD doses and 3 MAD doses of risvodetinib (IkT-148009) or placebo. Part 3 was a MAD study conducted at two doses in 14 participants with mild-to-moderate PD (MAD-PD). Primary outcome measures were safety, tolerability and pharmacokinetics. Exploratory outcomes in PD participants included clinical measures of PD state, GI function, and cerebrospinal fluid (CSF) concentration.

Results

108 patients were treated with no dropouts. The SAD tested doses ranging from 12.5 to 325 mg, while the MAD tested 25 to 200 mg and MAD-PD tested 50 to 100 mg in Parkinson's participants. All active doses had a favorable safety profile with no clinically meaningful adverse events. Single dose pharmacokinetics were approximately linear between 12.5 mg and 200 mg for both Cmax and AUC0 - inf without distinction between healthy volunteers and participants with PD. Exposures at each dose were high relative to other drugs in the same kinase inhibitor class.

Conclusions

Risvodetinib (IkT-148009) was well tolerated, had a favorable safety and pharmacology profile over 7-day dosing, did not induce serious adverse events and did not appear to induce deleterious side-effects in participants administered anti-PD medications.

Insights on the Correlation between Mitochondrial Dysfunction and the Progression of Parkinson's Disease

The aetiology of a progressive neuronal Parkinson's disease has been discussed in several studies. However, due to the multiple risk factors involved in its development, such as environmental toxicity, parental inheritance, misfolding of protein, ageing, generation of reactive oxygen species, degradation of dopaminergic neurons, formation of neurotoxins, mitochondria dysfunction, and genetic mutations, its mechanism of involvement is still discernible. Therefore, this study aimed to review the processes or systems that are crucially implicated in the conversion of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) into its lethal form, which directly blockades the performance of mitochondria, leading to the formation of oxidative stress in the dopaminergic neurons of substantia nigra pars compacta (SNpc) and resulting in the progression of an incurable Parkinson's disease. This review also comprises an overview of the mutated genes that are frequently associated with mitochondrial dysfunction and the progression of Parkinson's disease. Altogether, this review would help future researchers to develop an efficient therapeutic approach for the management of Parkinson's disease via identifying potent prognostic and diagnostic biomarkers.

Modulation of TRPV1 and TRPA1 Channels Function by Sea Anemones' Peptides Enhances the Viability of SH-SY5Y Cell Model of Parkinson's Disease

Cellular dysfunction during Parkinson's disease leads to neuroinflammation in various brain regions, inducing neuronal death and contributing to the progression of the disease. Different ion channels may influence the process of neurodegeneration. The peptides Ms 9a-1 and APHC3 can modulate the function of TRPA1 and TRPV1 channels, and we evaluated their cytoprotective effects in differentiated to dopaminergic neuron-like SH-SY5Y cells. We used the stable neuroblastoma cell lines SH-SY5Y, producing wild-type alpha-synuclein and its mutant A53T, which are prone to accumulation of thioflavin-S-positive aggregates. We analyzed the viability of cells, as well as the mRNA expression levels of TRPA1, TRPV1, ASIC1a channels, alpha-synuclein, and tyrosine hydroxylase after differentiation of these cell lines using RT-PCR. Overexpression of alpha-synuclein showed a neuroprotective effect and was accompanied by a reduction of tyrosine hydroxylase expression. A mutant alpha-synuclein A53T significantly increased the expression of the pro-apoptotic protein BAX and made cells more susceptible to apoptosis. Generally, overexpression of alpha-synuclein could be a model for the early stages of PD, while expression of mutant alpha-synuclein A53T mimics a genetic variant of PD. The peptides Ms 9a-1 and APHC3 significantly reduced the susceptibility to apoptosis of all cell lines but differentially influenced the expression of the genes of interest. Therefore, these modulators of TRPA1 and TRPV1 have the potential for the development of new therapeutic agents for neurodegenerative disease treatment.

Imaging Protein Aggregates in Parkinson's Disease Serum Using Aptamer-Assisted Single-Molecule Pull-Down

The formation of soluble α-synuclein (α-syn) and amyloid-β (Aβ) aggregates is associated with the development of Parkinson's disease (PD). Current methods mainly focus on the measurement of the aggregate concentration and are unable to determine their heterogeneous size and shape, which potentially also change during the development of PD due to increased protein aggregation. In this work, we introduce aptamer-assisted single-molecule pull-down (APSiMPull) combined with super-resolution fluorescence imaging of α-syn and Aβ aggregates in human serum from early PD patients and age-matched controls. Our diffraction-limited imaging results indicate that the proportion of α-syn aggregates (α-syn/(α-syn+Aβ)) can be used to distinguish PD and control groups with an area under the curve (AUC) of 0.85. Further, super resolution fluorescence imaging reveals that PD serums have a higher portion of larger and rounder α-syn aggregates than controls. Little difference was observed for Aβ aggregates. Combining these two metrics, we constructed a new biomarker and achieved an AUC of 0.90. The combination of the aggregate number and morphology provides a new approach to early PD diagnosis.

Ox-inflammasome involvement in neuroinflammation

Neuroinflammation plays a crucial role in the onset and the progression of several neuropathologies, from neurodegenerative disorders to migraine, from Rett syndrome to post-COVID 19 neurological manifestations. Inflammasomes are cytosolic multiprotein complexes of the innate immune system that fuel inflammation. They have been under study for the last twenty years and more recently their involvement in neuro-related conditions has been of great interest as possible therapeutic target. The role of oxidative stress in inflammasome activation has been described, however the exact way of action of specific endogenous and exogenous oxidants needs to be better clarified. In this review, we provide the current knowledge on the involvement of inflammasome in the main neuropathologies, emphasizing the importance to further clarify the role of oxidative stress in its activation including the role of mitochondria in inflammasome-induced neuroinflammation.

Diagnosis of Parkinson's disease based on voice signals using SHAP and hard voting ensemble method

Parkinson's disease (PD) is the second most common progressive neurological condition after Alzheimer's. The significant number of individuals afflicted with this illness makes it essential to develop a method to diagnose the conditions in their early phases. PD is typically identified from motor symptoms or via other Neuroimaging techniques. Expensive, time-consuming, and unavailable to the general public, these methods are not very accurate. Another issue to be addressed is the black-box nature of machine learning methods that needs interpretation. These issues encourage us to develop a novel technique using Shapley additive explanations (SHAP) and Hard Voting Ensemble Method based on voice signals to diagnose PD more accurately. Another purpose of this study is to interpret the output of the model and determine the most important features in diagnosing PD. The present article uses Pearson Correlation Coefficients to understand the relationship between input features and the output. Input features with high correlation are selected and then classified by the Extreme Gradient Boosting, Light Gradient Boosting Machine, Gradient Boosting, and Bagging. Moreover, the weights in Hard Voting Ensemble Method are determined based on the performance of the mentioned classifiers. At the final stage, it uses SHAP to determine the most important features in PD diagnosis. The effectiveness of the proposed method is validated using 'Parkinson Dataset with Replicated Acoustic Features' from the UCI machine learning repository. It has achieved an accuracy of 85.42%. The findings demonstrate that the proposed method outperformed state-of-the-art approaches and can assist physicians in diagnosing Parkinson's cases.

Defects in Mitochondrial Biogenesis Drive Mitochondrial Alterations in PINK1-deficient Human Dopamine Neurons

Mutations and loss of activity in the protein kinase PINK1 play a role in the pathogenesis of Parkinson's disease (PD). PINK1 regulates many aspects of mitochondrial quality control including mitochondrial autophagy (mitophagy), fission, fusion, transport, and biogenesis. Defects in mitophagy are though to play a predominant role in the loss of dopamine (DA) neurons in PD. Here we show that, although there are defects in mitophagy in human DA neurons lacking PINK1, mitochondrial deficits induced by the absence of PINK1 are primarily due to defects in mitochondrial biogenesis. Upregulation of PARIS and the subsequent down regulation of PGC-1a accounts for the mitochondrial biogenesis defects. CRISPR/Cas9 knockdown of PARIS completely restores the mitochondrial biogenesis defects and mitochondrial function without impacting the deficits in mitophagy due to the absence of PINK1. These results highlight the importance mitochondrial biogenesis in the pathogenesis of PD due to inactivation or loss of PINK1 in human DA neurons.

Mechanisms of Glucocerebrosidase Dysfunction in Parkinson's Disease

Beta-glucocerebrosidase is a lysosomal hydrolase, encoded by GBA1 that represents the most common risk gene associated with Parkinson's disease (PD) and Lewy Body Dementia. Glucocerebrosidase dysfunction has been also observed in the absence of GBA1 mutations across different genetic and sporadic forms of PD and related disorders, suggesting a broader role of glucocerebrosidase in neurodegeneration. In this review, we highlight recent advances in mechanistic characterization of glucocerebrosidase function as the foundation for development of novel therapeutics targeting glucocerebrosidase in PD and related disorders.

Rosinidin inhibits NF-κB/ Nrf2/caspase-3 expression and restores neurotransmitter levels in rotenone-activated Parkinson's disease

Objectives

The examination was sighted to study the preventive effects of rosinidin against rotenone-activated Parkinson's disease in rats.

Methods

Animals were randamoized into five groups: I-saline, II-rotenone (0.5 mg/kg/b.wt.), III- IV-10 and 20 mg/kg rosinidin after rotenone and V-20 mg/kg rosinidin per se for 28 days and were assigned for behavioral analysis., Biochemical parameters i.e. lipid peroxidation, endogenous antioxidants, nitrite level, neurotransmitter levels, proinflammatory biomarkers such as interleukin- 6 (IL-6), tumor necrosis factor-α, IL-1β, nuclear factor kappa B, nuclear factor erythroid 2-related factor 2, and caspase-3 were assessed on the 29th day of the research.

Results

Rosinidin augmented the effectiveness of rotenone on akinesia, catalepsy, forced-swim test, rotarod, and open-field test. Biochemical findings indicated that treatment of rosinidin showed restoring neuroinflammatory cytokines, antioxidants, and neurotransmitter levels in rotenone-injected rats.

Conclusion

As a result of rosinidin treatment, the brain was protected from oxidative stress-induced neuronal damage and inhibited neuroinflammatory cytokines.

The brain on time: links between development and neurodegeneration

Neurodegenerative diseases are characterized by the progressive loss of structure or function of neurons. In this Spotlight, we explore the idea that genetic forms of neurodegenerative disorders might be rooted in neural development. Focusing on Alzheimer's, Parkinson's and Huntington's disease, we first provide a brief overview of the pathology for these diseases. Although neurodegenerative diseases are generally thought of as late-onset diseases, we discuss recent evidence promoting the notion that they might be considered neurodevelopmental disorders. With this view in mind, we consider the suitability of animal models for studying these diseases, highlighting human-specific features of human brain development. We conclude by proposing that one such feature, human-specific regulation of neurogenic time, might be key to understanding the etiology and pathophysiology of human neurodegenerative disease.

Crucial neuroprotective roles of the metabolite BH4 in dopaminergic neurons

Dopa-responsive dystonia (DRD) and Parkinson's disease (PD) are movement disorders caused by the dysfunction of nigrostriatal dopaminergic neurons. Identifying druggable pathways and biomarkers for guiding therapies is crucial due to the debilitating nature of these disorders. Recent genetic studies have identified variants of GTP cyclohydrolase-1 (GCH1), the rate-limiting enzyme in tetrahydrobiopterin (BH4) synthesis, as causative for these movement disorders. Here, we show that genetic and pharmacological inhibition of BH4 synthesis in mice and human midbrain-like organoids accurately recapitulates motor, behavioral and biochemical characteristics of these human diseases, with severity of the phenotype correlating with extent of BH4 deficiency. We also show that BH4 deficiency increases sensitivities to several PD-related stressors in mice and PD human cells, resulting in worse behavioral and physiological outcomes. Conversely, genetic and pharmacological augmentation of BH4 protects mice from genetically- and chemically induced PD-related stressors. Importantly, increasing BH4 levels also protects primary cells from PD-affected individuals and human midbrain-like organoids (hMLOs) from these stressors. Mechanistically, BH4 not only serves as an essential cofactor for dopamine synthesis, but also independently regulates tyrosine hydroxylase levels, protects against ferroptosis, scavenges mitochondrial ROS, maintains neuronal excitability and promotes mitochondrial ATP production, thereby enhancing mitochondrial fitness and cellular respiration in multiple preclinical PD animal models, human dopaminergic midbrain-like organoids and primary cells from PD-affected individuals. Our findings pinpoint the BH4 pathway as a key metabolic program at the intersection of multiple protective mechanisms for the health and function of midbrain dopaminergic neurons, identifying it as a potential therapeutic target for PD.

Analyzing global features of magnetic resonance images in widespread neurodegenerative diseases: new hope to understand brain mechanism and robust neurodegenerative disease diagnosis

Neurodegenerative diseases are caused by progressive degeneration of the central nervous system (CNS)'s neuronal structure. Well-known diseases in this category include Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS), which are also addressed in this study. The CNS appears to be a complex dynamic system, whose parameters change during the disease due to neuronal damage, resulting in various symptoms. Since the change in dynamic behavior is due to the neurons' death and change in neurons' connectivity, brain images of the affected areas appear to provide a good understanding of this change. This work attempts to focus on brain magnetic resonance images (MRI) and examine the effect of neuronal loss on the images. To this end, the complex features of these images, including 2D and Higuchi's fractal dimensions (HFD), correlation dimension (CD), largest Lyapunov exponent (LLE), and approximate entropy (ApEn) were calculated. Despite small differences in numerical values (0.01-0.35), these values differ significantly. This shows that the brain dynamic system behaves and functions differently in the disease state, which is clear in the behavior of global features. These three diseases have the same functional pattern, and this study seems to have captured the roots of these seemingly variant diseases.

Has machine learning over-promised in healthcare? A critical analysis and a proposal for improved evaluation, with evidence from Parkinson’s disease

Adoption of artificial intelligence (AI) by the medical community has long been anticipated, endorsed by a stream of machine learning literature showcasing AI systems that yield extraordinary performance. However, many of these systems are likely over-promising and will under-deliver in practice. One key reason is the community's failure to acknowledge and address the presence of inflationary effects in the data. These simultaneously inflate evaluation performance and prevent a model from learning the underlying task, thus severely misrepresenting how that model would perform in the real world. This paper investigated the impact of these inflationary effects on healthcare tasks, as well as how these effects can be addressed. Specifically, we defined three inflationary effects that occur in medical data sets and allow models to easily reach small training losses and prevent skillful learning. We investigated two data sets of sustained vowel phonation from participants with and without Parkinson's disease, and revealed that published models which have achieved high classification performances on these were artificially enhanced due to the inflationary effects. Our experiments showed that removing each inflationary effect corresponded with a decrease in classification accuracy, and that removing all inflationary effects reduced the evaluated performance by up to 30%. Additionally, the performance on a more realistic test set increased, suggesting that the removal of these inflationary effects enabled the model to better learn the underlying task and generalize. Source code is available at https://github.com/Wenbo-G/pd-phonation-analysis under the MIT license.

Genetic Architecture of Parkinson's Disease

Year 2022 marks 25 years since the first mutation in familial autosomal dominant Parkinson's disease was identified. Over the years, our understanding of the role of genetic factors in the pathogenesis of familial and idiopathic forms of Parkinson's disease has expanded significantly - a number of genes for the familial form of the disease have been identified, and DNA markers for an increased risk of developing its sporadic form have been found. But, despite all the success achieved, we are far from an accurate assessment of the contribution of genetic and, even more so, epigenetic factors to the disease development. The review summarizes the information accumulated to date on the genetic architecture of Parkinson's disease and formulates issues that need to be addressed, which are primarily related to the assessment of epigenetic factors in the disease pathogenesis.

The c-Abl inhibitor IkT-148009 suppresses neurodegeneration in mouse models of heritable and sporadic Parkinson's disease

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease of the central nervous system, with an estimated 5,000,000 cases worldwide. PD pathology is characterized by the accumulation of misfolded α-synuclein, which is thought to play a critical role in the pathogenesis of the disease. Animal models of PD suggest that activation of Abelson tyrosine kinase (c-Abl) plays an essential role in the initiation and progression of α-synuclein pathology and initiates processes leading to degeneration of dopaminergic and nondopaminergic neurons. Given the potential role of c-Abl in PD, a c-Abl inhibitor library was developed to identify orally bioavailable c-Abl inhibitors capable of crossing the blood-brain barrier based on predefined characteristics, leading to the discovery of IkT-148009. IkT-148009, a brain-penetrant c-Abl inhibitor with a favorable toxicology profile, was analyzed for therapeutic potential in animal models of slowly progressive, α-synuclein-dependent PD. In mouse models of both inherited and sporadic PD, IkT-148009 suppressed c-Abl activation to baseline and substantially protected dopaminergic neurons from degeneration when administered therapeutically by once daily oral gavage beginning 4 weeks after disease initiation. Recovery of motor function in PD mice occurred within 8 weeks of initiating treatment concomitantly with a reduction in α-synuclein pathology in the mouse brain. These findings suggest that IkT-148009 may have potential as a disease-modifying therapy in PD.

Concomitant protein pathogenesis in Parkinson's disease and perspective mechanisms

Comorbidity is a common phenotype in Parkinson's disease (PD). Patients with PD not only have motor deficit symptoms, but also have heterogeneous non-motor symptoms, including cognitive impairment and emotional changes, which are the featured symptoms observed in patients with Alzheimer's disease (AD), frontotemporal dementia (FTD) and cerebrovascular disease. Moreover, autopsy studies have also confirmed the concomitant protein pathogenesis, such as the co-existences of α-synuclein, amyloid-β and tau pathologies in PD and AD patients' brains. Here, we briefly summarize the recent reports regarding the comorbidity issues in PD from both clinical observations and neuropathological evidences. Furthermore, we provide some discussion about the perspective potential mechanisms underlying such comorbidity phenomenon, with a focus on PD and related neurodegenerative diseases.

Naringin and Naringenin Polyphenols in Neurological Diseases: Understandings from a Therapeutic Viewpoint

The glycosides of two flavonoids, naringin and naringenin, are found in various citrus fruits, bergamots, tomatoes, and other fruits. These phytochemicals are associated with multiple biological functions, including neuroprotective, antioxidant, anticancer, antiviral, antibacterial, anti-inflammatory, antiadipogenic, and cardioprotective effects. The higher glutathione/oxidized glutathione ratio in 3-NP-induced rats is attributed to the ability of naringin to reduce hydroxyl radical, hydroperoxide, and nitrite. However, although progress has been made in treating these diseases, there are still global concerns about how to obtain a solution. Thus, natural compounds can provide a promising strategy for treating many neurological conditions. Possible therapeutics for neurodegenerative disorders include naringin and naringenin polyphenols. New experimental evidence shows that these polyphenols exert a wide range of pharmacological activity; particular attention was paid to neurodegenerative diseases such as Alzheimer's and Parkinson's diseases, as well as other neurological conditions such as anxiety, depression, schizophrenia, and chronic hyperglycemic peripheral neuropathy. Several preliminary investigations have shown promising evidence of neuroprotection. The main objective of this review was to reflect on developments in understanding the molecular mechanisms underlying the development of naringin and naringenin as potential neuroprotective medications. Furthermore, the configuration relationships between naringin and naringenin are discussed, as well as their plant sources and extraction methods.

Long non-coding RNA UCA1 regulates MPP+-induced neuronal damage through the miR-671-5p/KPNA4 pathway in SK-N-SH cells

Parkinson's disease (PD) is an age-related neurodegenerative disease. Long non-coding RNA urothelial carcinoma-associated 1 (UCA1) is involved in the pathogenesis of PD. However, the pathogenesis of PD regulated by UCA1 has not been fully explained. We used 1-Methyl-4-phenylpyridinium (MPP⁺)-induced SK-N-SH cells for functional analysis. Expression levels of UCA1, microRNA (miR)-671-5p, and KPNA4 (karyopherin subunit alpha 4) mRNA were detected using quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability and apoptosis were analyzed using MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) or flow cytometry assays. Some protein levels were measured by western blotting. The levels of pro-inflammatory cytokines were tested by ELISA (enzyme-linked immunosorbent assay). The levels of LDH (lactate dehydrogenase), MDA (malondialdehyde), and SOD (superoxide dismutase) were measured using corresponding kits. The relationship between UCA1 or KPNA4 and miR-671-5p was verified by dual-luciferase reporter assay and/or RNA immunoprecipitation (RIP) assay. MPP⁺ induced UCA1 expression in SK-N-SH cells in a concentration-dependent manner or time-dependent manner. UCA1 knockdown reduced MPP⁺-induced apoptosis, inflammation, and oxidative stress in SK-N-SH cells. MiR-671-5p was downregulated while KPNA4 was upregulated in MPP⁺-treated SK-N-SH cells. UCA1 sponged miR-671-5p to regulate KPNA4 expression. MiR-671-5p inhibition counteracted UCA1 knockdown-mediated influence on apoptosis, inflammation, and oxidative stress of MPP⁺-induced SK-N-SH cells. KPNA4 overexpression offset the inhibitory influence of miR-671-5p mimic on apoptosis, inflammation, and oxidative stress of MPP⁺-treated SK-N-SH cells. UCA1 inhibition reduced MPP⁺-induced neuronal damage through the miR-671-5p/KPNA4 pathway in SK-N-SH cells, providing a novel mechanism to understand the pathogenesis of PD.

Parkinson's Disease: Risk Factor Modification and Prevention

The global burden of Parkinson's disease (PD) has increased from 2.5 to 6.1 million since the 1990s. This is expected to rise as the world population ages and lives longer. With the current consensus on the existence of a prediagnostic phase of PD, which can be divided into a preclinical stage and a prodromal stage, we can better define the risk markers and prodromal markers of PD in the broader context of PD pathogenesis. Here, we review this pathogenetic process, and discuss the evidence behind various heritability factors, exposure to pesticides and farming, high dairy consumption, and traumatic brain injuries that have been known to raise PD risk. Physical activity, early active lifestyle, high serum uric acid, caffeine consumption, exposure to tobacco, nonsteroidal anti-inflammatory drugs, and calcium channel blockers, as well as the Mediterranean and the MIND diets are observed to lower PD risk. This knowledge, when combined with ways to identify at-risk populations and early prodromal PD patients, can help the clinician make practical recommendations. Most importantly, it helps us set the parameters for epidemiological studies and create the paradigms for clinical trials.

Neuronal NLRP3 is a parkin substrate that drives neurodegeneration in Parkinson's disease

Parkinson's disease (PD) is mediated, in part, by intraneuronal accumulation of α-synuclein aggregates andsubsequent death of dopamine (DA) neurons in the substantia nigra pars compacta (SNpc). Microglial hyperactivation of the NOD-like receptor protein 3 (NLRP3) inflammasome has been well-documented in various neurodegenerative diseases, including PD. We show here that loss of parkin activity in mouse and human DA neurons results in spontaneous neuronal NLRP3 inflammasome assembly, leading to DA neuron death. Parkin normally inhibits inflammasome priming by ubiquitinating and targeting NLRP3 for proteasomal degradation. Loss of parkin activity also contributes to the assembly of an active NLRP3 inflammasome complex via mitochondrial-derived reactive oxygen species (mitoROS) generation through the accumulation of another parkin ubiquitination substrate, ZNF746/PARIS. Inhibition of neuronal NLRP3 inflammasome assembly prevents degeneration of DA neurons in familial and sporadic PD models. Strategies aimed at limiting neuronal NLRP3 inflammasome activation hold promise as a disease-modifying therapy for PD.

Insights Into the Role of Mortalin in Alzheimer’s Disease, Parkinson’s Disease, and HIV-1-Associated Neurocognitive Disorders

Mortalin is a chaperone protein that regulates physiological functions of cells. Its multifactorial role allows cells to survive pathological conditions. Pharmacological, chemical, and siRNA-mediated downregulation of mortalin increases oxidative stress, mitochondrial dysfunction leading to unregulated inflammation. In addition to its well-characterized function in controlling oxidative stress, mitochondrial health, and maintaining physiological balance, recent evidence from human brain autopsies and cell culture–based studies suggests a critical role of mortalin in attenuating the damage seen in several neurodegenerative diseases. Overexpression of mortalin provides an important line of defense against accumulated proteins, inflammation, and neuronal loss, a key characteristic feature observed in neurodegeneration. Neurodegenerative diseases are a group of progressive disorders, sharing pathological features in Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and HIV-associated neurocognitive disorder. Aggregation of insoluble amyloid beta-proteins and neurofibrillary tangles in Alzheimer’s disease are among the leading cause of neuropathology in the brain. Parkinson’s disease is characterized by the degeneration of dopamine neurons in substantia nigra pars compacta. A substantial synaptic loss leading to cognitive decline is the hallmark of HIV-associated neurocognitive disorder (HAND). Brain autopsies and cell culture studies showed reduced expression of mortalin in Alzheimer’s, Parkinson’s, and HAND cases and deciphered the important role of mortalin in brain cells. Here, we discuss mortalin and its regulation and describe how neurotoxic conditions alter the expression of mortalin and modulate its functions. In addition, we also review the neuroprotective role of mortalin under neuropathological conditions. This knowledge showcases the importance of mortalin in diverse brain functions and offers new opportunities for the development of therapeutic targets that can modulate the expression of mortalin using chemical compounds.

Modeling Parkinson's disease-related symptoms in alpha-synuclein overexpressing mice

BACKGROUND

Intracellular deposition of alpha-synuclein (α-syn) as Lewy bodies and Lewy neurites is a central event in the pathogenesis of Parkinson's disease (PD) and other α-synucleinopathies. Transgenic mouse models overexpressing human α-syn, are useful research tools in preclinical studies of pathogenetic mechanisms. Such mice develop α-syn inclusions as well as neurodegeneration with a topographical distribution that varies depending on the choice of promoter and which form of α-syn that is overexpressed. Moreover, they display motor symptoms and cognitive disturbances that to some extent resemble the human conditions.

PURPOSE

One of the main motives for assessing behavior in these mouse models is to evaluate the potential of new treatment strategies, including their impact on motor and cognitive symptoms. However, due to a high within-group variability with respect to such features, the behavioral studies need to be applied with caution. In this review, we discuss how to make appropriate choices in the experimental design and which tests that are most suitable for the evaluation of PD-related symptoms in such studies.

METHODS

We have evaluated published results on two selected transgenic mouse models overexpressing wild type (L61) and mutated (A30P) α-syn in the context of their validity and utility for different types of behavioral studies.

CONCLUSIONS

By applying appropriate behavioral tests, α-syn transgenic mouse models provide an appropriate experimental platform for studies of symptoms related to PD and other α-synucleinopathies.

p21-activated kinase 4 controls the aggregation of α-synuclein by reducing the monomeric and aggregated forms of α-synuclein: involvement of the E3 ubiquitin ligase NEDD4-1

Aggregation of misfolded alpha-synuclein (α-synuclein) is a central player in the pathogenesis of neurodegenerative diseases. Therefore, the regulatory mechanism underlying α-synuclein aggregation has been intensively studied in Parkinson's disease (PD) but remains poorly understood. Here, we report p21-activated kinase 4 (PAK4) as a key regulator of α-synuclein aggregation. Immunohistochemical analysis of human PD brain tissues revealed an inverse correlation between PAK4 activity and α-synuclein aggregation. To investigate their causal relationship, we performed loss-of-function and gain-of-function studies using conditional PAK4 depletion in nigral dopaminergic neurons and the introduction of lentivirus expressing a constitutively active form of PAK4 (caPAK4; PAK4^S445N/S474E), respectively. For therapeutic relevance in the latter setup, we injected lentivirus into the striatum following the development of motor impairment and analyzed the effects 6 weeks later. In the loss-of-function study, Cre-driven PAK4 depletion in dopaminergic neurons enhanced α-synuclein aggregation, intracytoplasmic Lewy body-like inclusions and Lewy-like neurites, and reduced dopamine levels in PAK4^DAT-CreER mice compared to controls. Conversely, caPAK4 reduced α-synuclein aggregation, as assessed by a marked decrease in both proteinase K-resistant and Triton X100-insoluble forms of α-synuclein in the AAV-α-synuclein-induced PD model. Mechanistically, PAK4 specifically interacted with the NEDD4-1 E3 ligase, whose pharmacological inhibition and knockdown suppressed the PAK4-mediated downregulation of α-synuclein. Collectively, these results provide new insights into the pathogenesis of PD and suggest PAK4-based gene therapy as a potential disease-modifying therapy in PD.

Extracellular Alpha-Synuclein: Mechanisms for Glial Cell Internalization and Activation

Alpha-synuclein (α-syn) is a small protein composed of 140 amino acids and belongs to the group of intrinsically disordered proteins. It is a soluble protein that is highly expressed in neurons and expressed at low levels in glial cells. The monomeric protein aggregation process induces the formation of oligomeric intermediates and proceeds towards fibrillar species. These α-syn conformational species have been detected in the extracellular space and mediate consequences on surrounding neurons and glial cells. In particular, higher-ordered α-syn aggregates are involved in microglial and oligodendrocyte activation, as well as in the induction of astrogliosis. These phenomena lead to mitochondrial dysfunction, reactive oxygen and nitrogen species formation, and the induction of an inflammatory response, associated with neuronal cell death. Several receptors participate in cell activation and/or in the uptake of α-syn, which can vary depending on the α-syn aggregated state and cell types. The receptors involved in this process are of outstanding relevance because they may constitute potential therapeutic targets for the treatment of PD and related synucleinopathies. This review article focuses on the mechanism associated with extracellular α-syn uptake in glial cells and the consequent glial cell activation that contributes to the neuronal death associated with synucleinopathies.

Nobiletin Alleviates Astrocyte Activation and Oxidative Stress Induced by Hypoxia In Vitro

Increasing evidence indicates that nobiletin (NOB) is a promising neuroprotective agent. Astrocyte activation plays a key role in neurodegenerative disorders. Thus, this study aims to investigate the effects of NOB on astrocyte activation and the potential mechanisms. In this study, astrocytes were exposed to hypoxia injury for 24 h to induce activation in vitro. Glial fibrillary acidic protein (GFAP) was chosen as a marker of astrocyte activation. To evaluate the effects of NOB on the migration of activated astrocytes, we used a scratch wound healing assay and Transwell migration assay. In addition, the levels of reactive oxygen species (ROS), malondialdehyde (MDA), mitochondrial membrane potential, Nrf2 and HO-1 were measured to investigate the mechanisms of NOB in the activation of astrocytes. We found that NOB alleviated astrocyte activation and decreased GFAP expression during hypoxia. Simultaneously, NOB alleviated the migration of astrocytes induced by hypoxia. With NOB treatment, hypoxia-induced oxidative stress was partially reversed, including reducing the production of ROS and MDA. Furthermore, NOB significantly improved the mitochondrial dysfunction in activated astrocytes. Finally, NOB promoted Nrf2 nuclear translocation and HO-1 expression in response to continuous oxidative damage. Our study indicates, for the first time, that NOB alleviates the activation of astrocytes induced by hypoxia in vitro, in part by ameliorating oxidative stress and mitochondrial dysfunction. This provides new insights into the neuroprotective effects of NOB.

Role of miRNAs in Neurodegeneration: From Disease Cause to Tools of Biomarker Discovery and Therapeutics

Neurodegenerative diseases originate from neuronal loss in the central nervous system (CNS). These debilitating diseases progress with age and have become common due to an increase in longevity. The National Institute of Environmental Health Science’s 2021 annual report suggests around 6.2 million Americans are living with Alzheimer’s disease, and there is a possibility that there will be 1.2 million Parkinson’s disease patients in the USA by 2030. There is no clear-cut universal mechanism for identifying neurodegenerative diseases, and therefore, they pose a challenge for neurobiology scientists. Genetic and environmental factors modulate these diseases leading to familial or sporadic forms. Prior studies have shown that miRNA levels are altered during the course of the disease, thereby suggesting that these noncoding RNAs may be the contributing factor in neurodegeneration. In this review, we highlight the role of miRNAs in the pathogenesis of neurodegenerative diseases. Through this review, we aim to achieve four main objectives: First, we highlight how dysregulation of miRNA biogenesis led to these diseases. Second, we highlight the computational or bioinformatics tools required to identify the putative molecular targets of miRNAs, leading to biological molecular pathways or mechanisms involved in these diseases. Third, we focus on the dysregulation of miRNAs and their target genes leading to several neurodegenerative diseases. In the final section, we highlight the use of miRNAs as potential diagnostic biomarkers in the early asymptomatic preclinical diagnosis of these age-dependent debilitating diseases. Additionally, we discuss the challenges and advances in the development of miRNA therapeutics for brain targeting. We list some of the innovative strategies employed to deliver miRNA into target cells and the relevance of these viral and non-viral carrier systems in RNA therapy for neurodegenerative diseases. In summary, this review highlights the relevance of studying brain-enriched miRNAs, the mechanisms underlying their regulation of target gene expression, their dysregulation leading to progressive neurodegeneration, and their potential for biomarker marker and therapeutic intervention. This review thereby highlights ways for the effective diagnosis and prevention of these neurodegenerative disorders in the near future.

Longitudinal clustering analysis and prediction of Parkinson's disease progression using radiomics and hybrid machine learning

BACKGROUND

We employed machine learning approaches to (I) determine distinct progression trajectories in Parkinson's disease (PD) (unsupervised clustering task), and (II) predict progression trajectories (supervised prediction task), from early (years 0 and 1) data, making use of clinical and imaging features.

METHODS

We studied PD-subjects derived from longitudinal datasets (years 0, 1, 2 & 4; Parkinson's Progressive Marker Initiative). We extracted and analyzed 981 features, including motor, non-motor, and radiomics features extracted for each region-of-interest (ROIs: left/right caudate and putamen) using our standardized standardized environment for radiomics analysis (SERA) radiomics software. Segmentation of ROIs on dopamine transposer - single photon emission computed tomography (DAT SPECT) images were performed via magnetic resonance images (MRI). After performing cross-sectional clustering on 885 subjects (original dataset) to identify disease subtypes, we identified optimal longitudinal trajectories using hybrid machine learning systems (HMLS), including principal component analysis (PCA) + K-Means algorithms (KMA) followed by Bayesian information criterion (BIC), Calinski-Harabatz criterion (CHC), and elbow criterion (EC). Subsequently, prediction of the identified trajectories from early year data was performed using multiple HMLSs including 16 Dimension Reduction Algorithms (DRA) and 10 classification algorithms.

RESULTS

We identified 3 distinct progression trajectories. Hotelling's t squared test (HTST) showed that the identified trajectories were distinct. The trajectories included those with (I, II) disease escalation (2 trajectories, 27% and 38% of patients) and (III) stable disease (1 trajectory, 35% of patients). For trajectory prediction from early year data, HMLSs including the stochastic neighbor embedding algorithm (SNEA, as a DRA) as well as locally linear embedding algorithm (LLEA, as a DRA), linked with the new probabilistic neural network classifier (NPNNC, as a classifier), resulted in accuracies of 78.4% and 79.2% respectively, while other HMLSs such as SNEA + Lib_SVM (library for support vector machines) and t_SNE (t-distributed stochastic neighbor embedding) + NPNNC resulted in 76.5% and 76.1% respectively.

CONCLUSIONS

This study moves beyond cross-sectional PD subtyping to clustering of longitudinal disease trajectories. We conclude that combining medical information with SPECT-based radiomics features, and optimal utilization of HMLSs, can identify distinct disease trajectories in PD patients, and enable effective prediction of disease trajectories from early year data.

The Sphingolipid Asset Is Altered in the Nigrostriatal System of Mice Models of Parkinson’s Disease

Parkinson’s disease (PD) is a neurodegenerative disease incurable due to late diagnosis and treatment. Therefore, one of the priorities of neurology is to study the mechanisms of PD pathogenesis at the preclinical and early clinical stages. Given the important role of sphingolipids in the pathogenesis of neurodegenerative diseases, we aimed to analyze the gene expression of key sphingolipid metabolism enzymes (ASAH1, ASAH2, CERS1, CERS3, CERS5, GBA1, SMPD1, SMPD2, UGCG) and the content of 32 sphingolipids (subspecies of ceramides, sphingomyelins, monohexosylceramides and sphinganine, sphingosine, and sphingosine-1-phosphate) in the nigrostriatal system in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse models of the preclinical and clinical stages of PD. It has been shown that in PD models, the expression of five of the nine studied genes (CERS1, CERS5, ASAH1, ASAH2, and GBA1) increases but only in the substantia nigra (SN) containing dopaminergic cell bodies. Changes in the expression of enzyme genes were accompanied by an increase in the content of 7 of the 32 studied sphingolipids. Such findings suggest these genes as attractive candidates for diagnostic purposes for preclinical and clinical stages of PD.

Chemoproteomic-enabled characterization of small GTPase Rab1a as a target of an N-arylbenzimidazole ligand's rescue of Parkinson's-associated cell toxicity

The development of phenotypic models of Parkinson's disease (PD) has enabled screening and identification of phenotypically active small molecules that restore complex biological pathways affected by PD toxicity.

Deep learning reveals personalized spatial spectral abnormalities of high delta and low alpha bands in EEG of patients with early Parkinson's disease

Objective.Parkinson's disease (PD) is one of the most common neurodegenerative diseases, and early diagnosis is crucial to delay disease progression. The diagnosis of early PD has always been a difficult clinical problem due to the lack of reliable biomarkers. Electroencephalogram (EEG) is the most common clinical detection method, and studies have attempted to discover the EEG spectrum characteristics of early PD, but the reported conclusions are not uniform due to the heterogeneity of early PD patients. There is an urgent need for a more advanced algorithm to extract spectrum characteristics from EEG to satisfy the personalized requirements.Approach.The structured power spectral density with spatial distribution was used as the input of convolutional neural network (CNN). A visualization technique called gradient-weighted class activation mapping was used to extract the optimal frequency bands for identifying early PD. Based on the model visualization, we proposed a novel quantitative index of spectral characteristics, spatial-mapping relative power (SRP), to detect personalized abnormalities in the spatial spectral characteristics of EEG in early PD.Main results.We demonstrated the feasibility of applying CNN to identify the patients with early PD with an accuracy of 99.87% ± 0.03%. The models indicated the characteristic frequency bands (high-delta (3.5-4.5 Hz) and low-alpha (7.5-11 Hz) frequency bands) that are used to identify the early PD. The SRP of these two characteristic bands in early PD patients was significantly higher than that in the control group, and the abnormalities were consistent at the group and individual levels.Significance.This study provides a novel personalized detection algorithm based on deep learning to reveal the optimal frequency bands for identifying early PD and obtain the spatial frequency characteristics of early PD. The findings of this study will provide an effective reference for the auxiliary diagnosis of early PD in clinical practice.

Therapeutic Potential of α-Synuclein Evolvability for Autosomal Recessive Parkinson's Disease

The majority of Parkinson's disease (PD) is sporadic in elderly and is characterized by α-synuclein (αS) aggregation and other alterations involving mitochondria, ubiquitin-proteasome, and autophagy. The remaining are familial PD associated with gene mutations of either autosomal dominant or recessive inheritances. However, the former ones are similar to sporadic PD, and the latter ones are accompanied by impaired mitophagy during the reproductive stage. Since no radical therapies are available for PD, the objective of this paper is to discuss a mechanistic role for amyloidogenic evolvability, a putative physiological function of αS, among PD subtypes, and the potential relevance to therapy. Presumably, αS evolvability might benefit familial PD due to autosomal dominant genes and also sporadic PD during reproduction, which may manifest as neurodegenerative diseases through antagonistic pleiotropy mechanism in aging. Indeed, there are some reports describing that αS prevents apoptosis and mitochondrial alteration under the oxidative stress conditions, notwithstanding myriads of papers on the neuropathology of αS. Importantly, β-synuclein (βS), the nonamyloidogenic homologue of αS, might buffer against evolvability of αS protofibrils associated with neurotoxicity. Finally, it is intriguing to predict that increased αS evolvability through suppression of βS expression might protect against autosomal recessive PD. Collectively, further studies are warranted to better understand αS evolvability in PD pathogenesis, leading to rational therapy development.

Integrative genome-wide analysis of dopaminergic neuron-specific PARIS expression in Drosophila dissects recognition of multiple PPAR-γ associated gene regulation

The transcriptional repressor called parkin interacting substrate (PARIS; ZNF746) was initially identified as a novel co-substrate of parkin and PINK1 that leads to Parkinson’s disease (PD) by disrupting mitochondrial biogenesis through peroxisome proliferator-activated receptor gamma (PPARγ) coactivator -1α (PGC-1α) suppression. Since its initial discovery, growing evidence has linked PARIS to defective mitochondrial biogenesis observed in PD pathogenesis. Yet, dopaminergic (DA) neuron-specific mechanistic underpinnings and genome-wide PARIS binding landscape has not been explored. We employed conditional translating ribosome affinity purification (TRAP) followed by RNA sequencing (TRAP-seq) for transcriptome profiling of DA neurons in transgenic Drosophila lines expressing human PARIS wild type (WT) or mutant (C571A). We also generated genome-wide maps of PARIS occupancy using ChIP-seq in human SH-SY5Y cells. The results demonstrated that PPARγ functions as a master regulator of PARIS-induced molecular changes at the transcriptome level, confirming that PARIS acts primarily on PGC-1α to lead to neurodegeneration in PD. Moreover, we identified that PARIS actively modulates expression of PPARγ target genes by physically binding to the promoter regions. Together, our work revealed how PARIS drives adverse effects on modulation of PPAR-γ associated gene clusters in DA neurons.

Graph Theory on Brain Cortical Sources in Parkinson's Disease: The Analysis of 'Small World' Organization from EEG

Parkinson’s disease (PD) is the second most common neurodegenerative disease in the elderly population. Similarly to other neurodegenerative diseases, the early diagnosis of PD is quite difficult. The current pilot study aimed to explore the differences in brain connectivity between PD and NOrmal eLDerly (Nold) subjects to evaluate whether connectivity analysis may speed up and support early diagnosis. A total of 26 resting state EEGs were analyzed from 13 PD patients and 13 age-matched Nold subjects, applying to cortical reconstructions the graph theory analyses, a mathematical representation of brain architecture. Results showed that PD patients presented a more ordered structure at slow-frequency EEG rhythms (lower value of SW) than Nold subjects, particularly in the theta band, whereas in the high-frequency alpha, PD patients presented more random organization (higher SW) than Nold subjects. The current results suggest that PD could globally modulate the cortical connectivity of the brain, modifying the functional network organization and resulting in motor and non-motor signs. Future studies could validate whether such an approach, based on a low-cost and non-invasive technique, could be useful for early diagnosis, for the follow-up of PD progression, as well as for evaluating pharmacological and neurorehabilitation treatments.

Automatic Detection of K-Complexes Using the Cohen Class Recursiveness and Reallocation Method and Deep Neural Networks with EEG Signals

Evoked and spontaneous K-complexes are thought to be involved in sleep protection, but their role as biomarkers is still under debate. K-complexes have two major functions: first, they suppress cortical arousal in response to stimuli that the sleeping brain evaluates to avoid signaling danger; and second, they help strengthen memory. K-complexes also play an important role in the analysis of sleep quality, in the detection of diseases associated with sleep disorders, and as biomarkers for the detection of Alzheimer’s and Parkinson’s diseases. Detecting K-complexes is relatively difficult, as reliable methods of identifying this complex cannot be found in the literature. In this paper, we propose a new method for the automatic detection of K-complexes combining the method of recursion and reallocation of the Cohen class and the deep neural networks, obtaining a recursive strategy aimed at increasing the percentage of classification and reducing the computation time required to detect K-complexes by applying the proposed methods.

A Novel, Selective c-Abl Inhibitor, Compound 5, Prevents Neurodegeneration in Parkinson's Disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder that affects movement. The nonreceptor tyrosine kinase c-Abl has shown a potential role in the progression of PD. As such, c-Abl inhibition is a promising candidate for neuroprotection in PD and α-synucleinopathies. Compound 5 is a newly synthesized blood-brain barrier penetrant c-Abl inhibitor with higher efficacy than existing inhibitors. The objective of the current study was to demonstrate the neuroprotective effects of compound 5 on the α-synuclein preformed fibril (α-syn PFF) mouse model of PD. Compound 5 significantly reduced neurotoxicity, activation of c-Abl, and Lewy body pathology caused by α-syn PFF in cortical neurons. Additionally, compound 5 markedly ameliorated the loss of dopaminergic neurons, c-Abl activation, Lewy body pathology, neuroinflammatory responses, and behavioral deficits induced by α-syn PFF injection in vivo. Taken together, these results suggest that compound 5 could be a pharmaceutical agent to prevent the progression of PD and α-synucleinopathies.

Association of Serum Uric Acid Levels in Meige's Syndrome

Uric acid (URIC) is a natural antioxidant, and it has been shown that low levels of URIC could be a risk factor for the development of Parkinson’s disease. Our aim was to investigate whether URIC also plays a role in Meige’s syndrome (MS). We conducted a cohort study to compare serum URIC levels between patients with MS and healthy controls. In addition, we analyzed the impact of URIC on the risk of MS and symptom severity. Compared with normal subjects, URIC content was remarkably decreased in MS patients. In addition, URIC was regarded as a protective factor for MS, as verified by multivariate logistic regression models. We also found non-linear relationships between the levels of serum URIC and the incidence rate of MS and the Burke-Fahn-Marsden dystonia rating scale score. Our study is the first to show a connection between serum URIC levels and MS. Low serum URIC levels indicate an increased risk of MS incidence and more severe clinical symptoms. Our findings provide new insights into the prevention and treatment of MS.

The Positive Role and Mechanism of Herbal Medicine in Parkinson's Disease

Parkinson's disease (PD) is a complex neurodegenerative disease, manifested by the progressive functional impairment of the midbrain nigral dopaminergic neurons. Due to the unclear underlying pathogenesis, disease-modifying drugs for PD remain elusive. In Asia, such as in China and India, herbal medicines have been used in the treatment of neurodegenerative disease for thousands of years, which recently attracted considerable attention because of the development of curative drugs for PD. In this review, we first summarized the pathogenic factors of PD including protein aggregation, mitochondrial dysfunction, ion accumulation, neuroinflammation, and oxidative stress, and the related recent advances. Secondly, we summarized 32 Chinese herbal medicines (belonging to 24 genera, such as Acanthopanax, Alpinia, and Astragalus), 22 Chinese traditional herbal formulations, and 3 Indian herbal medicines, of which the ethanol/water extraction or main bioactive compounds have been extensively investigated on PD models both in vitro and in vivo. We elaborately provided pictures of the representative herbs and the structural formula of the bioactive components (such as leutheroside B and astragaloside IV) of the herbal medicines. Also, we specified the potential targets of the bioactive compounds or extractions of herbs in view of the signaling pathways such as PI3K, NF-κB, and AMPK which are implicated in oxidative and inflammatory stress in neurons. We consider that this knowledge of herbal medicines or their bioactive components can be favorable for the development of disease-modifying drugs for PD.