Etiology Of Parkinson's Disease Research Articles

Understanding Parkinson disease in Spain: Genetic and clinical insights.

Parkinson disease (PD) is a complex and heterogeneous neurodegenerative disorder with a broad spectrum of clinical manifestations, determined by a complex interplay of environmental and genetic factors. This study aimed to investigate genetic variants associated with PD and assess their impact on the disease phenotype through genotype-phenotype correlations. We employed a targeted resequencing panel to analyze 27 genes linked to PD in a cohort of 1185 PD patients from southern Spain. Variants were categorized based on the American College of Medical Genetics and Genomics pathogenicity criteria. Demographic and clinical data were also collected. Among the patients analyzed, 13.5% carried potential disease-causing pathogenic or likely pathogenic variants in 12 different genes, indicating significant genetic heterogeneity. The most frequently affected genes were LRRK2, PRKN, and GBA1 (accounting for 72.1% of positive cases). Sex-specific differences were observed, with a higher proportion of female patients carrying LRRK2 variants. Differences in age at onset and clinical features were also observed among the different mutated genes. Notably, variants in genes associated with atypical parkinsonism presented distinct clinical presentations, highlighting the importance of genetic factors in the differential diagnosis. Our study provides valuable information on the genetic landscape of PD and its clinical manifestations. The observed genotype-phenotype correlations, along with sex-specific differences, emphasize the complexity of PD pathogenesis, underlining the importance of personalized approaches to PD diagnosis and treatment. Further investigations into genetic interactions and population-specific effects are warranted to enhance our understanding of PD etiology and improve patient care.

Gut Microbiota and Parkinson’s disease - a prospective analysis of the FINRISK 2002 Study

Abstract Background Parkinson’s disease (PD) is a neurodegenerative movement disorder with mainly unknown etiology. Constipation is a common symptom, and changes in gut microbiota may play role in PD pathogenesis. Previous studies exploring microbial associations to PD have been mostly cross-sectional, and the role of microorganisms in PD etiology remains unclear. Thus, we examined the association between microbiota features and incident PD in a prospective cohort design. Methods In the FINRISK 2002 Study, 7231 participants gave a stool sample that underwent shotgun metagenomic sequencing. Participants with missing stool sample, incomplete covariate data, pregnancy, antibiotic use, and prevalent cases were excluded (final n = 5562). Cox regression models, adjusted for age, sex, education, smoking, coffee consumption, diabetes, cardiovascular events, and constipation, were used to assess associations between incident PD and microbiota features, ie. alpha diversity (the number of different species present in a sample), beta diversity (the differences in microbial composition between individuals), and abundance of 381 core taxa (compositional detection rate of at least 0.1% and a prevalence of 1%). 120 incident cases of PD, identified through register linkage, occurred during a median follow-up of 17.8 years. Results In the multivariate models, PD incidence was not associated with the Shannon index, a measure on alpha diversity, (p-value 0.81), or with the ten first principal component axes in beta diversity analysis (p-values ranging between 0.49-0.91). In permutational analysis, PD did not explain differences in the composition of the gut microbiota (R2 <0.001, p-value 0.46)). None of the core species were associated with PD incidence (all FDR-corrected p-values > 0.05). Conclusions This prospective study showed no support for an association between gut microbiota features and incident PD. Key messages • Previous findings associating gut microbiota with PD may be due to the cross-sectional design, ie. PD affecting the gut microbiota. • Suggestions to screen gut bacteria to identify people at high risk of Parkinson’s disease are vastly premature as the scientific evidence is inconclusive.

Exposure to Metals, Pesticides, and Air Pollutants: Focus on Resulting DNA Methylation Changes in Neurodegenerative Diseases

Individuals affected by neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS), are dramatically increasing worldwide. Thus, several efforts are being made to develop strategies for stopping or slowing the spread of these illnesses. Although causative genetic variants linked to the onset of these diseases are known, they can explain only a small portion of cases. The etiopathology underlying the neurodegenerative process in most of the patients is likely due to the interplay between predisposing genetic variants and environmental factors. Epigenetic mechanisms, including DNA methylation, are central candidates in translating the effects of environmental factors in genome modulation, and they play a critical role in the etiology of AD, PD, and ALS. Among the main environmental exposures that have been linked to an increased risk for these diseases, accumulating evidence points to the role of heavy metals, pesticides, and air pollutants. These compounds could trigger neurodegeneration through different mechanisms, mainly neuroinflammation and the induction of oxidative stress. However, increasing evidence suggests that they are also capable of inducing epigenetic alterations in neurons. In this article, we review the available literature linking exposure to metals, pesticides, and air pollutants to DNA methylation changes relevant to neurodegeneration.

LRRK2; Communicative Role in the Treatment of Parkinson's Disease and Ulcerative Colitis Overlapping.

Involvement of gastrointestinal inflammation in Parkinson's disease (PD) pathogenesis and movement have progressively emerged. Inflammation is involved in the etiology of both PD and inflammatory bowel disease (IBD). Transformations in leucine-rich recurrent kinase 2 (LRRK2) are among the best hereditary supporters of IBD and PD. Elevated levels of LRRK2 have been reported in stimulated colonic tissue from IBD patients and peripheral invulnerable cells from irregular PD patients; thus, it is thought that LRRK2 directs inflammatory cycles. Since its revelation, LRRK2 has been seriously linked in neurons, albeit various lines of proof affirmed that LRRK2 is profoundly communicated in invulnerable cells. Subsequently, LRRK2 might sit at a junction by which stomach inflammation and higher LRRK2 levels in IBD might be a biomarker of expanded risk for inconsistent PD or potentially may address a manageable helpful objective in incendiary sicknesses that increment the risk of PD. Here, we discuss how PD and IBD share covering aggregates, especially regarding LRRK2 and present inhibitors, which could be a helpful objective in ongoing treatments. English data were obtained from Google Scholar, PubMed, Scopus, and Cochrane library studies published between 1990-December 2022. Inhibitors of the LRRK2 pathway can be considered as the novel treatment approaches for IBD and PD treatment. Common mediators and pathways are involved in the pathophysiology of IBD and PD, which are majorly correlated with inflammatory situations. Such diseases could be used for further clinical investigations.

SNPs in cytochromes P450 catalyzing cholesterol degradation in brain are associated with Parkinson's disease.

Besides being an essential structural component of plasma membranes and the precursor of many functional compounds and signaling molecules, cholesterol was also proposed to play a role in the etiology and/or manifestation of Parkinson's disease (PD). However, so far systematic investigations on the role of cholesterol and its metabolites present in the brain for the etiology of PD are missing. Here, we investigate for the first time the association of PD with SNPs in the genes of four cytochromes P450 (P450), CYP46A1, CYP39A1, CYP27A1 and CYP7B1, which are critical for the degradation of cholesterol in the brain. Analyzing 1,349 individuals from the PPMI data base, we found 24 SNPs in these four genes, which are significantly over- or under-represented in patients suffering from idiopathic PD (IPD). Studying each of the 362 IPD patients individually, we found that most patients (45%) showed only one associated SNP in one of the four P450 genes, while 31% displayed two associated SNPs and 18% three associated SNPs. The occurrence of some associated SNPs is in the same order of magnitude as SNPs in the GBA (beta-glucocerebrosidase) and thus might reflect a genetic predisposition for PD. As all 24 SNPs were located in introns and 3' untranslated regions, we evaluated the prospective regulatory impact of the surrounding genomic regions by using transcriptome and epigenome data from the Foundational Data Initiative for Parkinson Disease (FOUNDIN-PD). FOUNDIN-PD provides gene expression, open chromatin and DNA methylation data in a cohort of 89 induced pluripotent stem cell (iPSC) lines differentiated to dopaminergic (DA) neurons derived from people in the PPMI study. Indeed, two of the 24 SNPs, one in CYP7B1 (rs118111353) and the other one in CYP27A1 (rs74446825), were localized within a region of open chromatin in differentiated neurons. Interestingly, all iPSC lines with open chromatin in rs118111353 showed the reference allele. As all four P450, CYP46A1, CYP39A1, CYP27A1 and CYP7B1, are expressed in dopaminergic neurons, we discuss further functional studies to connect SNPs in regulatory regions with gene expression levels. Finally, potential possibilities for personalized therapeutic treatment of patients with SNPs in the four investigated P450 are discussed.

Liver X receptor α contribution to neuroinflammation and glial cells activation induced by MPTP: Implications for Parkinson’s disease

Parkinson’s disease (PD) is the second most common neurodegenerative disorder whose etiology remains unknown. The immune system has been implicated in hallmarks of PD including aggregation of α-synuclein and death of dopaminergic neurons in the substantia nigra. As a core regulator of immune response and inflammation, liver X receptors (LXRs) have been shown to have protective effects in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD. With two isoforms of LXRs (LXRα and LXRβ) expressed in the brain, their roles and distributions in this tissue remain largely unexplored. Here, we used MPTP to mimic symptoms and biomedical changes seen in PD in LXRα-/- and wild-type mice to investigate the role of LXRα in the etiology and progression of PD. We found that MPTP is unable to induce motor deficits, anxiety-like behavior in LXRα-/- mice, which has been seen in WT mice. Gene ontology analysis of RNA sequencing revealed that knockout of LXRα led to enrichment of the process, including immune response and inflammation in the midbrain. In addition, MPTP did not lead to dopaminergic neuron death in the striatum and substantia nigra in LXRα-/- mice, the basal GFAP protein level, and pro-inflammatory cytokines were elevated in LXRα-/- mice. Lastly, the microglia activation and astrogliosis caused by MPTP intoxication we found in WT mice were abolished in LXRα-/- mice. To sum up, we conclude that LXRα is a critical regulator in MPTP intoxication and may play a unique role in astrogliosis seen in the neuroinflammation of PD.

Dietary Natural Flavonoids: Intervention for MAO-B Against Parkinson's Disease.

Parkinson's disease (PD) stands as the second most common neurological disorder after Alzheimer's disease, primarily affecting the elderly population and significantly compromising their quality of life. The precise etiology of PD remains elusive, but recent research has shed light on potential factors, including the formation of α-synuclein aggregates, oxidative stress, neurotransmitter imbalances, and dopaminergic neurodegeneration in the substantia nigra pars compacta (SNpc) region of the brain, culminating in motor symptoms such as bradykinesia, akinesia, tremors, and rigidity. Monoamine oxidase (MAO) is an essential enzyme, comprising two isoforms, MAO-A and MAO-B, responsible for the oxidation of monoamines such as dopamine. Increased MAO-B activity is responsible for decreased dopamine levels in the SNpc region of mid brain which is remarkably associated with the pathogenesis of PD-like manifestations. Inhibitors of MAO-B enhance striatal neuronal responses to dopamine, making them valuable in treating PD, which involves dopamine deficiency. Clinically approved MAO-B inhibitors such as selegiline, L-deprenyl, pargyline, and rasagiline are employed in the management of neurodegenerative conditions associated with PD. Current therapeutic interventions including MAO-B inhibitors for PD predominantly aim to alleviate these motor symptoms but often come with a host of side effects that can be particularly challenging for the patients. While effective, they have limitations, prompting a search for alternative treatments, there is a growing interest in exploring natural products notably flavonoids as potential sources of novel MAO-B inhibitors. In line with that, the present review focuses on natural flavonoids of plant origin that hold promise as potential candidates for the development of novel MAO-B inhibitors. The discussion encompasses both invitro and invivo studies, shedding light on their potential therapeutic applications. Furthermore, this review underscores the significance of exploring natural products as valuable reservoirs of MAO-B inhibitors, offering new avenues for drug development and addressing the pressing need for improved treatments in PD-like pathological conditions. The authors of this review majorly explore the neuroprotective potential of natural flavonoids exhibiting notable MAO-B inhibitory activity and additionally multi-targeted approaches in the treatment of PD with clinical evidence and challenges faced in current therapeutic approaches.

Lauric acid with or without levodopa ameliorates Parkinsonism in genetically modified model of Drosophila melanogaster via the oxidative-inflammatory-apoptotic pathway.

Parkinson's disease (PD), the most prevalent type of Parkinsonism, is a progressive neurological condition characterized by a range of motor and non-motor symptoms. The complicated etiology of PD is thought to involve a summation of aging, genetic predisposition, and environmental variables. However, the α-synuclein protein plays a significant role in the disease's pathophysiology. The UAS-α-Syn and Ddc-Gal4 strains were crossed to produce offspring referred to as PD flies. The entire population of flies was divided into five groups, each having about 100 flies and five replicates. The control group (w1118) and the PD group not receiving treatment were exposed to lauric acid (LA)/levodopa (LD)-free diet, while the PD groups that received treatments were fed with either a 250mg/kg LA diet, a 250mg/kg LD diet, or a combination of the two for 21 days. Longevity, geotaxis, and olfactory assays were performed in addition to other biochemical tests. As a result of the overexpression of α-synuclein, the locomotive capacity, lifespan, and antioxidant status were all significantly (p<.05)reduced, and the apoptotic and neuroinflammatory activities were increased. Nevertheless, the majority of the treated flies improved significantly (p<.05). LA, whether combined with LD or not, elicited a significant response in α-synuclein/dopa decarboxylase genetically modified Drosophila melanogaster Parkinsonism models.

Unveiling the link: hepatitis C virus and Parkinson’s disease

BackgroundParkinson disease (PD) is one of the disabling neurological disorders. The etiology of Parkinson disease is still unknown. Hepatitis C virus is one of the neurotropic viruses which is incriminated in the pathogenesis of Parkinson disease. Hepatitis C virus might affect the dopaminergic neurons, affecting the advancement of PD.MethodsThis study is observational, cross-sectional study done on 2 phases: one phase on PD patients without history of HCV and another phase on HCV patients with no history of PD. 104 PD patient were tested for HCV antibodies and 40 HCV patients with various grades of liver fibrosis were assessed for early pre-motor symptoms of parkinsonism.ResultsAmong patients with parkinsonism, HCV Abs testing was negative in all the studied patients. On the other hand, chronic HCV group included 40 patients, 27.5% were cirrhotic (11/40). Child C patients showed significantly higher percentages of non-motor parkinsonian symptoms, and regarding the HCV group, the majority (85%) of the patients show cognitive impairment, (27.5%) were at stage 1 of anxious mood, while half (50%) of the patients were at stage 1 of fatigue as evaluated by UPDRS Score. Cirrhosis was a significant factor for having non-motor (early) parkinsonism.ConclusionHere we show that advanced cirrhosis is associated with a variety of neurological symptoms including parkinsonian, which needs awareness for better preventive and therapeutic measures for early treatment of hepatitis avoiding the occurrence of cirrhosis, which can lead to parkinsonism.

The Genetic Architecture of Parkinson's Disease in the AfrAbia Population: Current State and Future Perspectives.

Over 80% of genetic studies in the Parkinson's disease (PD) field have been conducted on individuals of European descent. There is a social and scientific imperative to understand the genetic basis of PD across global populations for therapeutic development and deployment. PD etiology is impacted by genetic and environmental factors that are variable by ancestry and region, emphasising the need for worldwide programs to gather large numbers of patients to identify novel candidate genes and risk loci involved in disease. Only a handful of documented genetic assessments have investigated families with PD in AfrAbia, which comprises the member nations of the Arab League and the African Union, with very limited cohort and case-control studies reported. This review article summarises prior research on PD genetics in AfrAbia, highlighting gaps and challenges. We discuss the etiological risk spectrum in the context of historical interactions, highlighting allele frequencies, penetrance, and the clinical manifestations of known genetic variants in the AfrAbian PD patient community.

Gut Microbiota-Induced Modulation of the Central Nervous System Function in Parkinson's Disease Through the Gut-Brain Axis and Short-Chain Fatty Acids.

Recent insights into Parkinson's disease (PD), a progressive neurodegenerative disorder, suggest a significant influence of the gut microbiome on its pathogenesis and progression through the gut-brain axis. This study integrates 16S rRNA sequencing, high-throughput transcriptomic sequencing, and animal model experiments to explore the molecular mechanisms underpinning the role of gut-brain axis in PD, with a focus on short-chain fatty acids (SCFAs) mediated by the SCFA receptors FFAR2 and FFAR3. Our findings highlighted prominent differences in the gut microbiota composition between PD patients and healthy individuals, particularly in taxa such as Escherichia_Shigella and Bacteroidetes, which potentially impact SCFA levels through secondary metabolite biosynthesis. Notably, fecal microbiota transplantation (FMT) from healthy to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse models significantly improved motor function, enhanced dopamine and serotonin levels in the striatum, and increased the number of dopaminergic neurons in the substantia nigra while reducing glial cell activation. This therapeutic effect was associated with increased levels of SCFAs such as acetate, propionate, and butyrate in the gut of MPTP-lesioned mice. Moreover, transcriptomic analyses revealed upregulated expression of FFAR2 and FFAR3 in MPTP-lesioned mice, indicating their crucial role in mediating the benefits of FMT on the central nervous system. These results provide compelling evidence that gut microbiota and SCFAs play a critical role in modulating the gut-brain axis, offering new insights into PD's etiology and potential targets for therapeutic intervention.

Revolutionizing our understanding of Parkinson's disease: Dr. Heinz Reichmann's pioneering research and future research direction.

Millions of individuals around the world are afflicted with Parkinson's disease (PD), a prevalent and incapacitating neurodegenerative disorder. Dr. Reichmann, a distinguished professor and neurologist, has made substantial advancements in the domain of PD research, encompassing both fundamental scientific investigations and practical applications. His research has illuminated the etiology and treatment of PD, as well as the function of energy metabolism and premotor symptoms. As a precursor to a number of neurotransmitters and neuromodulators that are implicated in the pathophysiology of PD, he has also investigated the application of tryptophan (Trp) derivatives in the disease. His principal findings and insights are summarized and synthesized in this narrative review article, which also emphasizes the challenges and implications for future PD research. This narrative review aims to identify and analyze the key contributions of Reichmann to the field of PD research, with the ultimate goal of informing future research directions in the domain. By examining Reichmann's work, the study seeks to provide a comprehensive understanding of his major contributions and how they can be applied to advance the diagnosis and treatment of PD. This paper also explores the potential intersection of Reichmann's findings with emerging avenues, such as the investigation of Trp and its metabolites, particularly kynurenines, which could lead to new insights and potential therapeutic strategies for managing neurodegenerative disorders like PD.

The Gut Microbiome as a Catalyst and Emerging Therapeutic Target for Parkinson's Disease: A Comprehensive Update.

Parkinson's Disease is the second most prevalent neurological disorder globally, and its cause is still largely unknown. Likewise, there is no cure, and existing treatments do little more than subdue symptoms before becoming ineffective. It is increasingly important to understand the factors contributing to Parkinson's Disease aetiology so that new and more effective pharmacotherapies can be established. In recent years, there has been an emergence of research linking gut dysbiosis to Parkinson's Disease via the gut-brain axis. Advancements in microbial profiling have led to characterisation of a Parkinson's-specific microbial signature, where novel treatments that leverage and correct gut dysbiosis are beginning to emerge for the safe and effective treatment of Parkinson's Disease. Preliminary clinical studies investigating microbiome-targeted therapeutics for Parkinson's Disease have revealed promising outcomes, and as such, the aim of this review is to provide a timely and comprehensive update of the most recent advances in this field. Faecal microbiota transplantation has emerged as a novel and potential frontrunner for microbial-based therapies due to their efficacy in alleviating Parkinson's Disease symptomology through modulation of the gut-brain axis. However, more rigorous clinical investigation, along with technological advancements in diagnostic and in vitro testing tools, are critically required to facilitate the widespread clinical translation of microbiome-targeting Parkinson's Disease therapeutics.

Copper-mediated neurotoxicity and genetic vulnerability in the background of neurodegenerative diseases in C. elegans.

The mechanisms associated with neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD), have yet to be fully characterized, and genetic as well as environmental factors in their disease etiology are underappreciated. Although mutations in genes such as PARKIN and LRRK2 have been linked to PD, the idiopathic component of the disease suggests a contribution of environmental risk factors, including metals, such as copper (Cu). Cu overexposure has been reported to cause oxidative stress and neurotoxicity, but its role in neurodegenerative diseases is rarely studied. Using Caenorhabditis elegans (C. elegans) as a model organism for neurotoxicity, we assessed the effects of Cu oversupply in AD and PD models. Our findings reveal that although copper treatment did not induce neurodegeneration in wild-type worms or the AD model, it significantly exacerbated neurodegeneration in the PD-associated mutants PARKIN and LRRK2. These results suggest that genetic predisposition for PD enhances the sensitivity to copper toxicity, highlighting the multifactorial nature of neurodegenerative diseases. Furthermore, our study provides insight into the mechanisms underlying Cu-induced neurotoxicity in PD models, including disruptions in dopamine levels, altered dopamine-dependent behavior and degraded dopaminergic neurons. Overall, our novel findings contribute to a better understanding of the complex interactions between genetic susceptibility, environmental factors, and neurodegenerative disease pathogenesis, emphasizing the importance of a tightly regulated Cu homeostasis in the etiology of PD. Copper oversupply exacerbated neurodegeneration in Caenorhabditis elegans models of Parkinson's disease, highlighting the genetic susceptibility and emphasizing the crucial role of tightly regulated copper homeostasis in Parkinson's disease pathogenesis.

PARK7/DJ-1 deficiency impairs microglial activation in response to LPS-induced inflammation

BackgroundSpecific microglia responses are thought to contribute to the development and progression of neurodegenerative diseases, including Parkinson’s disease (PD). However, the phenotypic acquisition of microglial cells and their role during the underlying neuroinflammatory processes remain largely elusive. Here, according to the multiple-hit hypothesis, which stipulates that PD etiology is determined by a combination of genetics and various environmental risk factors, we investigate microglial transcriptional programs and morphological adaptations under PARK7/DJ-1 deficiency, a genetic cause of PD, during lipopolysaccharide (LPS)-induced inflammation.MethodsUsing a combination of single-cell RNA-sequencing, bulk RNA-sequencing, multicolor flow cytometry and immunofluorescence analyses, we comprehensively compared microglial cell phenotypic characteristics in PARK7/DJ-1 knock-out (KO) with wildtype littermate mice following 6- or 24-h intraperitoneal injection with LPS. For translational perspectives, we conducted corresponding analyses in human PARK7/DJ-1 mutant induced pluripotent stem cell (iPSC)-derived microglia and murine bone marrow-derived macrophages (BMDMs).ResultsBy excluding the contribution of other immune brain resident and peripheral cells, we show that microglia acutely isolated from PARK7/DJ-1 KO mice display a distinct phenotype, specially related to type II interferon and DNA damage response signaling, when compared with wildtype microglia, in response to LPS. We also detected discrete signatures in human PARK7/DJ-1 mutant iPSC-derived microglia and BMDMs from PARK7/DJ-1 KO mice. These specific transcriptional signatures were reflected at the morphological level, with microglia in LPS-treated PARK7/DJ-1 KO mice showing a less amoeboid cell shape compared to wildtype mice, both at 6 and 24 h after acute inflammation, as also observed in BMDMs.ConclusionsTaken together, our results show that, under inflammatory conditions, PARK7/DJ-1 deficiency skews microglia towards a distinct phenotype characterized by downregulation of genes involved in type II interferon signaling and a less prominent amoeboid morphology compared to wildtype microglia. These findings suggest that the underlying oxidative stress associated with the lack of PARK7/DJ-1 affects microglia neuroinflammatory responses, which may play a causative role in PD onset and progression.

Crosstalk between gut-brain axis: unveiling the mysteries of gut ROS in progression of Parkinson's disease.

"Path to a good mood lies through the gut." This statement seems to imply that it has long been believed that the gut is connected with the brain. Research has shown that eating food activates the reward system and releases dopamine (DA), establishing a link between the peripheral and central nervous system. At the same time, researchers also trust that the gut is involved in the onset of many diseases, including Parkinson's disease (PD), in which gastrointestinal dysfunction is considered a prevalent symptom. Reports suggest that PD starts from the gut and reaches the brain via the vagus nerve. Recent studies have revealed an intriguing interaction between the gut and brain, which links gut dysbiosis to the etiology of PD. This review aims to explore the mechanistic pathway how reactive oxygen species (ROS) generation in the gut affects the makeup and operation of the dopamine circuitry in the brain. Our primary concern is ROS generation in the gut, which disrupts the gut microbiome (GM), causing α-synuclein accumulation and inflammation. This trio contributes to the loss of DA neurons in the brain, resulting in PD development. This review also compiles pre-clinical and clinical studies on antioxidants, demonstrating that antioxidants reduce ROS and increase DA levels. Collectively, the study highlights the necessity of comprehending the gut-brain axis for unraveling the riddles of PD pathogenesis and considering new therapeutic approaches.

Exploring α-synuclein stability under the external electrostatic field: Effect of repeat unit

Parkinson’s disease (PD) is a category of neurodegenerative disorders (ND) that currently lack comprehensive and definitive treatment strategies. The etiology of PD can be attributed to the presence and aggregation of a protein known as α-synuclein. Researchers have observed that the application of an external electrostatic field holds the potential to induce the separation of the fibrous structures into peptides. To comprehend this phenomenon, our investigation involved simulations conducted on the α-synuclein peptides through the application of Molecular Dynamics (MD) simulation techniques under the influence of a 0.1 V/nm electric field. The results obtained from the MD simulations revealed that in the presence of external electric field, the monomer and oligomeric forms of α-synuclein are experienced significant conformational changes which could prevent them from further aggregation. However, as the number of peptide units in the model system increases, forming trimers and tetramers, the stability against the electric field also increases. This enhanced stability in larger aggregates indicates a critical threshold in α-synuclein assembly where the electric field’s effectiveness in disrupting the aggregation diminishes. Therefore, our findings suggest that early diagnosis and intervention could be crucial in preventing PD progression. When α-synuclein predominantly exists in its monomeric or dimeric form, applying even a lower electric field could effectively disrupt the initial aggregation process. Inhibition of α-synuclein fibril formation at early stages might serve as a viable solution to combat PD by halting the formation of more stable and pathogenic α-synuclein fibrils.

Gut-Brain Axis in Focus: Polyphenols, Microbiota, and Their Influence on α-Synuclein in Parkinson's Disease.

With the recognition of the importance of the gut-brain axis in Parkinson's disease (PD) etiology, there is increased interest in developing therapeutic strategies that target α-synuclein, the hallmark abhorrent protein of PD pathogenesis, which may originate in the gut. Research has demonstrated that inhibiting the aggregation, oligomerization, and fibrillation of α-synuclein are key strategies for disease modification. Polyphenols, which are rich in fruits and vegetables, are drawing attention for their potential role in this context. In this paper, we reviewed how polyphenols influence the composition and functional capabilities of the gut microbiota and how the resulting microbial metabolites of polyphenols may potentially enhance the modulation of α-synuclein aggregation. Understanding the interaction between polyphenols and gut microbiota and identifying which specific microbes may enhance the efficacy of polyphenols is crucial for developing therapeutic strategies and precision nutrition based on the microbiome.

The Effect of Neuronal CoQ10 Deficiency and Mitochondrial Dysfunction on a Rotenone-Induced Neuronal Cell Model of Parkinson's Disease.

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder currently affecting the ageing population. Although the aetiology of PD has yet to be fully elucidated, environmental factors such as exposure to the naturally occurring neurotoxin rotenone has been associated with an increased risk of developing PD. Rotenone inhibits mitochondrial respiratory chain (MRC) complex I activity as well as induces dopaminergic neuronal death. The aim of the present study was to investigate the underlying mechanisms of rotenone-induced mitochondrial dysfunction and oxidative stress in an in vitro SH-SY5Y neuronal cell model of PD and to assess the ability of pre-treatment with Coenzyme Q10 (CoQ10) to ameliorate oxidative stress in this model. Spectrophotometric determination of the mitochondrial enzyme activities and fluorescence probe studies of reactive oxygen species (ROS) production was assessed. Significant inhibition of MRC complex I and II-III activities was observed, together with a significant loss of neuronal viability, CoQ10 status, and ATP synthesis. Additionally, significant increases were observed in intracellular and mitochondrial ROS production. Remarkably, CoQ10 supplementation was found to reduce ROS formation. These results have indicated mitochondrial dysfunction and increased oxidative stress in a rotenone-induced neuronal cell model of PD that was ameliorated by CoQ10 supplementation.

Exploring the Role of Ubiquitin-Proteasome System in the Pathogenesis of Parkinson's Disease.

Parkinson's disease (PD) is a prevalent neurodegenerative disorder among the elderly population. The pathogenesis of PD encompasses genetic alterations, environmental factors, and age-related neurodegenerative processes. Numerous studies have demonstrated that aberrant functioning of the ubiquitin-proteasome system (UPS) plays a crucial role in the initiation and progression of PD. Notably, E3 ubiquitin ligases serve as pivotal components determining substrate specificity within UPS and are intimately associated with the regulation of various proteins implicated in PD pathology. This review comprehensively summarizes the mechanisms by which E3 ubiquitin ligases and deubiquitinating enzymes modulate PD-associated proteins and signaling pathways, while exploring the intricate relationship between UPS dysfunctions and PD etiology. Furthermore, this article discusses recent research advancements regarding inhibitors targeting PD-related E3 ubiquitin ligases.