npj Parkinson's Disease

Parkinsons disease (PD) is increasingly recognized as a multi-system disorder with immune dysregulation extending beyond the central nervous system. Although numerous studies have examined peripheral immune alterations in people with PD, findings remain heterogenous and difficult to reconcile. To clarify the current landscape, we conducted a comprehensive scoping review of human studies profiling peripheral blood immune cells in PD. Following PRISMA-ScR guidelines, we systematically screened the literature and curated studies reporting in vivo and ex vivo immune characterizations from PD patients. Eligible studies based on pre-defined criteria were assessed for patient demographics and clinical variables, experimental and analytical approaches, and reported immune outcomes. Our synthesis reveals a steady expansion and diversification of peripheral immune cell research in PD especially over the last decade. Deep immunophenotyping identifies convergent signatures across in vivo studies of both innate and adaptive compartments, including expanded pro-inflammatory T-cell subsets, altered monocyte subset distributions, increased cytotoxic natural killer cells and neutrophil-to-lymphocyte ratio, and dysregulated pathways related to immune activation, chemotaxis, mitochondrial function, and autophagy-lysosomal processes. Stimulation-based ex vivo assays further demonstrate recurrent T-cell hyper-responsiveness in PD, whereas myeloid cell responses are more variable and context dependent. Critically, this review highlights substantial variability and under-reporting in study design, which impeded our ability to make strong conclusions relating to many aspects of PD peripheral immunity.

Parkinsons disease (PD) is a progressive age-related neurodegenerative disorder characterized by both motor and non-motor symptoms. The poorly understood prodromal period, decades-long progression, and disease-phenotype heterogeneity continue to impede the development of preventive and curative therapies. A growing appreciation of immune system changes during the progression of PD suggests that evaluating peripheral immune cells may help identify signatures relevant to disease etiology. We employed single-cell RNA sequencing to profile the transcriptomes of peripheral blood mononuclear cells (PBMCs) from a cohort of 12 patients with PD and 12 healthy controls, equally distributed by sex. Analysis identified gene expression signatures specific to immune cell lineages in PD when compared with healthy controls. Analysis of the dataset indicated that aspects of the PD-related changes were associated with sex, including metabolic and inflammatory changes. Further analysis of myeloid and T cell subsets identified additional pathways and gene expression profiles associated with PD. Trajectory analysis of the myeloid and T cell datasets indicated significant changes in the distribution of cells across states of gene expression in PD compared with controls. This work provides new evidence of peripheral immune cell changes in PD utilizing high-resolution transcriptomics in a cohort powered to analyze sex as a variable. HighlightsTranscriptomic dataset in a cohort powered to analyze immune phenotype in Parkinsons disease Parkinsons disease-specific gene expression signatures in peripheral immune cell lineages Identification of sex differences in the immune cell transcriptome in Parkinsons disease Trajectory analysis identifies changes in immune cell phenotypic distribution in Parkinsons monocytes

Synucleinopathies can be biologically advanced before overt parkinsonism is clinically apparent, highlighting the need for objective, sensitive motor endpoints. We examined the mThy1--synuclein line 61 (L61-Tg) mouse, which shows progressive synucleinopathy with early circuit dysfunction, using an integrated pipeline combining CatWalk XT gait analysis and markerless pose estimation from the same CatWalk videos. Two cohorts of male L61-Tg and nontransgenic littermates were assessed at 12 and 18 months. DeepLabCut tracking of four landmarks showed highest accuracy at the tail base. We thus quantified mediolateral instability as within-run variance of tail-base lateral position. L61-Tg mice exhibited increased tail-base lateral variance at both ages. CatWalk mixed-effects modeling identified six genotype-dependent parameters at 12 months, and a progressive increase in hind base of support at 18 months. Comparison across measures showed that discrimination between L61-Tg and non-transgenic was similarly high for hind base of support and tail-base lateral instability the two were nonetheless synergistic, and the approaches are therefore complementary to one-another in the determination of synucleinopathy motor phenotypes. This combined gait-pose strategy provides scalable, interpretable endpoints for preclinical Parkinson-like phenotyping and therapeutic testing.

Adeno-associated viral (AAV)-mediated overexpression of human wildtype -synuclein (-syn) in the substantia nigra (SN) is a widely used approach to model Parkinsons disease (PD) in rodents. However, variability in the ability of AAV-based systems to induce nigrostriatal pathology and motor deficits has limited reproducibility across studies, especially in mice. Here, we systematically optimized key vector features - AAV serotype, promoter, viral titer - to establish a highly efficient and reliable mouse model of PD. We compared the tropism and expression efficiency of mixed AAV2/1 and AAV2/rh10 serotypes combined with three promoters - CMV enhancer/chicken {beta}-actin (CBA), human Synapsin (hSYN), and rat Tyrosine Hydroxylase (TH) - to drive human -syn gene (SNCA) expression in nigral dopaminergic neurons. The AAV.TH.SNCA vector, delivered at an optimized titer, achieved selective and sustained -syn overexpression in nigral neurons, resulting in nigro-striatal neurochemical changes and progressive motor deficits preceding overt neuronal loss. Fine tuning -syn expression proved critical for detecting early disease processes: lower AAV.TH.SNCA titer induced early pathological signatures, including -syn hyperphosphorylation and neuroinflammation, whereas higher titers produced robust nigrostriatal degeneration not achieved with other promoter constructs. Notably, we demonstrate that motor and neurochemical impairments can occur prior to dopaminergic cell death, implicating microglial activation and -syn pathology as primary drivers of dysfunction. This observation is consistent with human genetic evidence showing that triplication of the wild-type SNCA gene alone can cause Parkinsonian pathology, highlighting that our model enables the use of a single experimental reagent to investigate the molecular, cellular, and behavioral consequences of controlled increases in -syn expression. This novel AAV.TH.SNCA model provides a powerful and versatile platform for investigating mechanisms of a -syn-mediated neurotoxicity and for evaluating disease modifying interventions targeting early, pre-degenerative stages of PD. HighlightsO_LITitrated -syn expression uncouples early dysfunction from dopaminergic neuron loss C_LIO_LIAAV2/rh10-TH-SNCA model captures prodromal and degenerative PD stages C_LIO_LIMotor deficits arise from -syn pathology and nigral molecular changes before neurodegeneration. C_LI

BackgroundParkinsons disease (PD) is a neurodegenerative disorder for which there is currently no cure or reliable biomarker for early detection or for evaluating the effectiveness of potential treatments. PD pathology is driven by misfolding and subsequent accumulation of alpha-synuclein (Syn) protein into pathological aggregates within neurons and glial cells. Seed amplification assay (SAA) is a highly sensitive and specific diagnostic tool developed to detect pathological Syn species in the cerebrospinal fluid (CSF) of PD patients. However, Syn aggregates are present in multiple tissues and biosamples, including stools. In this study, we aimed to investigate the potential diagnostic value of SAA using stool samples from PD patients and healthy controls (HC). MethodsStool samples from PD patients (n=45) and healthy controls (n=35) were analysed for the presence of Syn species using slot blot assays with a panel of six Syn antibodies, and ELISA assays. Samples were subjected to SAA, and the end-point products (SAA EP) were characterised using transmission electron microscopy (TEM). Extracellular vesicles (EVs) were isolated from the subset of samples (n=5 per group) using size exclusion chromatography and characterized by TEM. The seeding activity of isolated EVs was evaluated using SAA, followed by TEM analysis of SAA EP. ResultsProtein extracts from both PD and HC stool samples revealed pathological Syn species in the slot blot assay using the phosphorylated Syn antibody, pS129 and conformation-specific antibodies, MJFR-14 and 5G4. ELISA showed significantly elevated total Syn levels in PD samples compared to HC, although no differences in aggregated Syn levels were detected. In stool protein extracts, SAA demonstrated 55.6% sensitivity and 60% specificity. When applied to stool-derived EVs from PD patients and controls, sensitivity increased to 100%, while specificity remained at 60%. Notably, SAA applied to stool-derived EVs pre-incubated with recombinant monomeric Syn achieved 100% sensitivity and 100% specificity. ConclusionThese findings suggest that SAA applied to EVs isolated from stool samples, particularly after pre-incubation with recombinant monomeric Syn, may serve as a valuable, non-invasive screening tool for the diagnosis of PD.

Background-Synuclein (-Syn) plays a central role in Parkinsons disease (PD). Under pathological conditions, -Syn aggregates into toxic oligomers and fibrils that act as damage-associated molecular patterns (DAMPs), stimulating microglial reactivity. This -Syn-microglia axis creates a self-perpetuating cycle of neuroinflammation and neurodegeneration, accelerating dopaminergic neuron loss in the substantia nigra pars compacta (SNpc) and contributing to motor deficits. Moreover, -Syn pathology spreads through the brain, disrupting synaptic plasticity in cognitive regions like the cortex and hippocampus, leading to early cognitive decline. Thus, targeting -Syn aggregation and its inflammatory consequences presents a promising dual-hit therapeutic strategy for PD. MethodsThis study investigates the therapeutic potential of 3-monothiopomalidomide (3MP), a novel thalidomide derivative designed to reduce neuroinflammation with a potentially better safety profile than Pomalidomide (POM). The neuroprotective and anti-inflammatory effects of 3MP were evaluated in rat primary mesencephalic mixed neuron-microglia cultures exposed to human -Syn oligomers (H-SynOs). Anti-aggregation activity was assessed via Thioflavin T (ThT) assays and Thioflavin S (ThS) staining in SH-SY5Y cells. Finally, the anti-aggregation, anti-inflammatory, and neuroprotective effects of 3MP were evaluated in vivo in a rat model of PD induced by intracerebral infusion of H-SynOs. ResultsIn primary cell cultures, 3MP dose-dependently reduced -Syn-induced neuronal death and microglial inflammatory responses. It also significantly inhibited -Syn aggregation in vitro in the ThT assay and in SH-SY5Y cells exposed to -Syn protofibrils, outperforming POM. When chronically administered in vivo, 3MP preserved dopaminergic neurons within the SNpc and yielded functional benefits on motor and cognitive readouts. Notably, 3MP markedly attenuated -Syn aggregates induced by the H-SynOs infusion in the SNpc more efficiently than POM, as shown by reduced intraneuronal staining for pSer129--Syn+ and reduced pSer129-Syn in both cytoplasmic and phagolysosomal compartments of microglia. In addition, mesencephalic and cortical inflammatory microgliosis that followed to intranigral H-SynOs-infusion, were significantly dampened by 3MP. ConclusionsOverall, 3MP emerges as a dual-action drug candidate capable of modulating neuroinflammation and -Syn aggregation and thereby disrupting the -Syn-driven inflammatory cycle. Its neuroprotective effects and favourable safety profile support its potential as a disease-modifying therapy for PD, with promising implications for clinical translation.

Body-first Lewy body disease (LBD) is hypothesized to begin in the peripheral autonomic nervous system, years before nigrostriatal involvement. Isolated REM sleep behaviour disorder (iRBD) is considered prodromal body-first LBD, but the duration of the prodromal phase remains unknown. We aimed to determine the progression rate of cardiac sympathetic denervation using [123I]meta-iodobenzylguanidine (MIBG) scintigraphy and employ the resulting curves to estimate the prodromal period of body-first LBD. We analysed longitudinal MIBG and dopaminergic imaging data from three cohorts: early Parkinsons disease (PD) patients from KPD, Korea (KPD-PD; n=195); de novo PD (n=74) and iRBD (n=54) patients from the PACE cohort, Aarhus, Denmark; and DaT SPECT data from PPMI PD (n=426) and iRBD (n=37). Heart-to-mediastinum ratios (MIBG) and putamen-to-occipital ratios (DaT SPECT) were converted to percent of normal value (healthy control mean). Patients were binned into quartiles according to baseline imaging data and progression curves were constructed by using median decline rates within each quartile. Onset of cardiac sympathetic (peripheral) and nigrostriatal dopaminergic (central) neurodegeneration were determined for iRBD patients by back-extrapolation from baseline imaging values. Longitudinal MIBG trajectories were highly consistent across the KPD and PACE cohorts, showing a rapid early decline ([~]10%-points/year) followed by gradual slowing, reaching 50% of normal value after [~]5 years and 25% after [~]10 years. PACE-iRBD patients displayed severe baseline cardiac sympathetic loss (median 21.3% of normal), corresponding to an estimated onset of peripheral neurodegeneration 11.3 years prior to study enrolment. Dopaminergic decline was slightly slower, reaching 50% of normal value after [~]8 years and 25% after [~]15 years. PACE-iRBD patients exhibited mild baseline dopaminergic deficit (median 81.6% of normal), indicating onset of nigrostriatal degeneration 2.7 years prior to enrolment. Thus, cardiac sympathetic degeneration preceded nigrostriatal involvement by 8.6 years. Based on baseline dopaminergic degeneration in PACE-PD patients, predicted time to phenoconversion for PACE-iRBD patients was 8.4 years. The combined model estimated the total prodromal period in body-first LBD to exceed 19 years. In conclusion, our study suggests that cardiac sympathetic degeneration begins more than a decade before study enrolment in iRBD subjects and nearly two decades before LBD diagnosis. Therefore, MIBG scintigraphy is a robust biomarker for detecting the earliest measurable neurodegeneration of body-first LBD and may be integrated in biological staging of -synucleinopathies. Furthermore, our findings have implications for drug trial design in SAA-positive individuals, and for identifying patients at the optimal window for disease-modifying therapies.

Mitochondrial and lysosomal dysfunction are central features of Parkinsons disease (PD) across major genetic forms including PRKN, SNCA, and LRRK2. We applied cell morphomics, a machine-learning-based framework combining high-content imaging with quantitative feature extraction, to analyse mitochondrial and lysosomal morphology at single-cell resolution in iPS cell-derived cortical neurons from PD patients and healthy controls (13 lines total). Supervised machine-learning models distinguished PD neurons from controls with high accuracy (AUC = 0.87) and reliably separated individual genotypes. Feature importance and attribution analysis revealed genotype-specific organelle biases, with mitochondrial features dominating classification in PRKN neurons, balanced mitochondrial and lysosomal contributions in SNCA neurons, and a greater lysosomal contribution in LRRK2 neurons. Multi-class models retained strong performance, and findings were reproduced across two independent laboratories using different dyes and imaging conditions. These results demonstrate that morphomics provides a robust and scalable framework to quantify genotype-specific organelle abnormalities in PD neurons and supports its application for cellular stratification and biomarker discovery.

Studies reporting alpha-synuclein seed amplification assay (aSyn-SAA) results are often cross-sectional. Here we investigated the intra-individual consistency of aSyn-SAA results over time from participants in the Parkinson's Progression Marker Initiative (PPMI). A total of 1238 participants had >1 CSF aSyn-SAA result for analysis (Parkinson's disease [PD]=633, prodromal =563, healthy control [HC]=42) which were collected over a median (min, max) of 2.0 (0.4, 11.4) years. Emphasis was placed on evaluating consistency in less common results such as aSyn-SAA- PD participants, aSyn-SAA+ HC and conversion rates from aSyn-SAA negative to positive results prodromal participants. Of aSyn-SAA+ PD participants, 96% (474/493, 95%CI 94-98%) remained positive in subsequent samples, and 92% (116/126, 95%CI 86-96%) of aSyn-SAA- PD participants remained negative. 99% (303/307, 95%CI 97-99%) of aSyn-SAA+ prodromal participants remained positive, and 95% (234/247, 95%CI 91-97%) of aSyn-SAA- prodromal participants remained negative. 89% (16/18, 95%CI 67-97%) of aSyn-SAA+ HC participants remained positive, and 87% (20/23, 95%CI 68-95%) of aSyn-SAA- HC participants remained negative. These results confirm a high consistency of aSyn-SAA results over time, even in less expected results.

We report Multiomics Spatial Image Analysis (MSIA), a suite of technologies that include streamlined manual and semi-automated workflows to image 100s of RNAs from fresh frozen and formalin-fixed paraffin-embedded (FFPE) samples, contextualize RNAs with select protein markers including imaging synaptic protein interactions, a data analysis pipeline that includes corrections for chromatic aberration, algorithms for image stitching, deep learning models for image analysis (cell segmentation and RNA dot detection using hundreds of RNAscope images) from multiple stain-image cycles and proof of concept for a language model trained on extensive Parkinsons Disease (PD) literature. We used the language model to identify potential new biomarkers that were confirmed in MPTP-treated mouse model of PD. Furthermore, by incorporating more stain-image cycles alongside an additional fluorescent channel and advanced error-correcting decoding schemes, the MSIA workflow demonstrates the scalability to potentially quantify over 1,000 genes.

Parkinsons disease (PD), dementia with Lewy Bodies (DLB) and multiple system atrophy (MSA) are progressive neurodegenerative disorders marked by the pathological aggregation of alpha-synuclein ([a]Syn). Despite significant research efforts, effective therapeutic interventions remain elusive due to limited understanding of the cellular effects of [a]Syn aggregation and propagation. This study presents the development of a scalable cellular seeding assay for screening small molecules targeting cellular [a]Syn seeded aggregation. By leveraging a fluorescent reporter of [a]Syn and phenotypic screening, the assay enables high-throughput evaluation of potential inhibitors in a cellular environment mimicking disease pathology. We evaluated three different Syn aggregation inhibitors tested in clinical trials for PD: Minzasolmin, Emrusolmin and EGCG and profiled gene expression using multiplexed single cell RNA sequencing in order to examine their distinct effects on cellular pathways associated with [a]Syn overexpression or seeded aggregation. Two cellular activities were prominently affected: lipid metabolism and rRNA processing. Notably, while EGCG effects were confined to cells with aggregated Syn, Minzasolmin and Emrusolmin also produced transcriptional changes in cells without aggregated Syn. Each of the compounds tested induced a partial reversal of transcriptional effects resulting from Syn seeded aggregation. We identified 391 genes that were no longer significantly differentially expressed upon addition of compound, relative to cells with seeded aggregation. This platform bridges phenotypic screening and molecular pathway analysis, providing insights into druggable pathways for synucleinopathies. The molecular signatures identified here can assist in testing and benchmarking future drug discovery leads.

Background. Parkinson's disease (PD) diagnosis remains delayed and suboptimally accurate, largely due to clinical overlap with atypical parkinsonian syndromes and the lack of reliable biomarkers. Here, we evaluated the performance of a previously patented 6-metabolites blood biomarker (6M-BB) for the differential diagnosis of PD and its translation to clinical IVDr NMR platform. Methods. Patient serum samples from de novo PD (n=30), multiple system atrophy (MSA, n=30), progressive supranuclear palsy (PSP, n=30), Alzheimer's disease (AD, n=33), and healthy individuals (n=29), were profiled by 1H NMR and classified using the 6M-BB. For clinical use, we rebuilt the model on absolute concentrations acquired on a Bruker Avance IVDr 600 MHz system. Results. The 6M-BB validation yielded 0.902 AUC and 87.9% accuracy for PD vs. HC (sensitivity 86.7%, specificity 89.3%), with an overall accuracy of 82.6% across all groups. The IVDr-based refit achieved 0.878 AUC (overall accuracy 77%). Adding VLDL-5 free cholesterol (V5FC) and citrate markedly improved performance to 0.959 AUC, with 94.9% accuracy for PD vs. HC (sensitivity 96.7%, specificity 93.1%) and 84.9% when MSA/PSP were included. Conclusion. The externally validated 6M-BB has demonstrated its robustness for the differential diagnosis of PD compared to other parkinsonian syndromes at de novo stage. Its successful transfer to a fully automated, standardized IVDr machine, with gains from V5FC and citrate, supports the feasibility and promising potential for clinical implementation, justifying future prospective multicenter studies.

BackgroundFilamentation induced by cAMP domain-containing protein (FICD) is an endoplasmic reticulum (ER)-resident adenylyltransferase that catalyzes protein AMPylation, a post-translational modification. Although FICD-mediated AMPylation has been linked to the fine-tuning of proteostasis and neuronal integrity, its role in neurodegenerative diseases characterized by protein dyshomeostasis remains unclear. Parkinsons disease (PD) is defined by dopaminergic neurodegeneration and aggregation of -synuclein (aSyn) as a consequence of impaired protein homeostasis. We therefore investigated whether dysregulated FICD-mediated AMPylation contributes to PD pathogenesis. MethodsWe combined analyses of human post-mortem PD brain tissue with complementary models, including midbrain dopaminergic neurons derived from human induced pluripotent stem cells (hiPSCs) of a PD patient carrying an SNCA gene duplication and its isogenic gene dosage-corrected control line, transgenic mouse models of synucleinopathy, and an aSyn-overexpressing H4 neuroglioma cell model. Genetic and pharmacological modulation of FICD activity was integrated with multi-proteomic approaches, including chemical proteomics-based AMPylation profiling, stable isotope labelling with amino acids in cell culture-based global protein turnover analysis, and whole-proteome profiling to identify AMPylation-associated molecular pathways. ResultsFICD was preferentially expressed in dopaminergic neurons and was upregulated in SNCA duplication PD patient-derived neurons, as well as in the basal ganglia of PD post-mortem brains and synucleinopathy mice. Despite this overall increase, the proportion of FICD-expressing dopaminergic neurons was reduced under PD conditions, suggesting selective vulnerability of dopaminergic neurons to FICD. Mechanistically, FICD selectively AMPylated lysosomal proteins, thereby linking AMPylation to the regulation of degradative pathways. Moreover, hyperactivation of FICD-induced AMPylation triggered ER stress, impaired lysosomal function, reduced protein turnover, and ultimately promoted aSyn aggregation and apoptotic cell death. Importantly, pharmacological inhibition of AMPylation reversed aSyn pathology and neurite degeneration in PD patient-derived neurons. ConclusionsWe identify the pathological relevance of FICD-mediated AMPylation in PD-related neurodegeneration and its contribution to aSyn aggregation through a bidirectional interplay with aSyn pathology. Our findings support FICD-mediated AMPylation as a defining molecular switch regulating intracellular protein homeostasis in PD and highlight the FICD-AMPylation pathway as a potential therapeutic target for restoring aSyn pathology and mitigating disease progression.

BackgroundParkinsons disease (PD) is a prevalent neurodegenerative disorder characterized by progressive motor dysfunction and broad cellular impairment, including significant disruptions in lysosomal function, lipid metabolism, and intracellular trafficking. Glycosphingolipids (GSLs), critical for various cellular processes, depend on effective lysosomal degradation. Aberrant GSL metabolism has been linked to PD pathology, and glycoprotein non-metastatic melanoma protein B (GPNMB) has emerged as a biomarker associated with lysosomal dysfunction and lipid imbalance in PD. ObjectivesTo assess the relationship between GPNMB and GSL levels in cerebrospinal fluid (CSF) and plasma from PD patients and controls within the BioFIND cohort. We also investigated potential sex differences and associations with PD-related biomarkers such as -synuclein. MethodsGSL species and GPNMB protein levels were quantified using high-performance liquid chromatography (HPLC) and ELISA assays, respectively, in matched CSF and plasma samples from PD patients and controls. ResultsLevels of the paraglobosides GSL species, alpha-2,3SpG and pGb were significantly elevated in the plasma of PD patients compared to healthy controls, while levels of the ganglioside GD1a and the lacto-series GSL, Leb combined (GD1a + Leb), were significantly reduced in PD. GPNMB levels positively correlated with several GSL species in both plasma and CSF. Plasma GSLs and GPNMB concentrations were significantly higher in females compared to males, independent of PD diagnosis. CSF GPNMB correlated positively with age and -synuclein concentrations. InterpretationOur findings confirm that GSL metabolism is altered in PD. They also highlight significant sex-based biochemical variations in GSL and GPNMB levels, emphasizing the need for sex-specific analyses in PD biomarker research. The relationship between GSLs and GPNMB supports their potential as interconnected biomarkers of lipid pathology in PD.

Braak and others have proposed that Lewy body pathology LBP in Parkinson disease PD may arise not only in the brain but alternatively from an initial site in the gastrointestinal GI tract with subsequent passage to the central nervous system CNS through the vagus nerve or other routes. We tested this hypothesis by using both immunohistochemistry IHC and RT QuIC a form of alpha synuclein seed amplification assay SAA to detect alpha synuclein LBP in samples from selected brain regions and 10 GI tract sites taken from autopsies of 50 PD subjects and 128 elderly subjects without parkinsonism or dementia including 34 with IHC identified CNS incidental Lewy body disease ILBD and 94 with no Lewy body IHC pathology detected NLB. A positive SAA or IHC result was restricted to the GI tract in only 2 subjects while LBP by either SAA or IHC was restricted to the brain in 11 subjects. To fairly compare GI only with brain only synucleinopathy however we would have to do SAA on brain samples from all ILBD and NLB cases in at least 4 critical brain regions olfactory bulb medulla pons and amygdala. Further SAA of brain regions is estimated based on the proportional results to date to potentially identify 21 additional brain only LBP subjects total of 32 if it were done on all of the NLB subjects. From this brain only LBP is estimated to be 16 times more common than GI only LBP. To assess the clinical impact of SAA positive GI sites we found that the number of positive sites per subject is significantly correlated with UPDRS motor score and SCOPA AUT GI related scores including those for salivation straining constipation and bowel movement.

The synaptic vesicle glycoprotein 2C (SV2C) is a synaptic protein involved in the regulation of dopamine release. It is expressed in striatum, globus pallidus and substantia nigra, regions involved in the regulation of motor function. Genome-wide association studies, animal model and human brain tissue data indicate a strong link between SV2C and Parkinso[n]s disease, suggesting a potential role of SV2C as synaptic marker for Parkinso[n]s disease. We hypothesize that a positron emission tomography (PET) radioligand for SV2C can serve as imaging marker for Parkinso[n]s disease, enabling early diagnosis and assessment of disease progression. This study was therefore designed to develop a PET radioligand for imaging SV2C. UCB-1A was the lead candidate selected from a library of compounds developed by UCB BioPharma. A translational approach was used, including autoradiography and in vitro binding studies with [3H]UCB-1A, and in vivo PET studies with [11C]UCB-1A in non-human primates (NHPs). The KD of [3H]UCB-1A for rat and human SV2C ranged between 6 and 15 nM, with >100-fold selectivity towards SV2A and SV2B. Specific binding of [3H]UCB-1A in rat and NHP brains was observed in substantia nigra, globus pallidus, striatum and brainstem nuclei, consistent with the expression of SV2C, and was decreased in the striatum of 6-hydroxydopamine-lesioned rats and in the putamen of Parkinson donors. UCB-1A was successfully radiolabelled with 11C and PET studies in NHPs demonstrated that [11C]UCB-1A displays suitable pharmacokinetic properties, a brain distribution consistent with the expression of SV2C and is selective for SV2C. [11C]UCB-1A is the first PET radioligand for in vivo imaging of SV2C and a potential synaptic marker for in vivo studies in Parkinso[n]s disease.

Parkinsons disease (PD) exhibits well-established sex differences in prevalence and clinical phenotypes, yet the underlying molecular mechanisms remain largely elusive. Here, we conducted a comprehensive sex-stratified multi-omic integration to identify sex-specific causal proteins and biological pathways in PD. We performed gene-based association analysis, transcriptome-wide association studies (TWAS), and proteome-wide Mendelian randomization (PWMR) with colocalization analysis using GWAS summary statistics from the International PD Genetics Consortium (IPDGC; 12,054 male cases/11,999 controls; 7,384 female cases/12,389 controls) for sex-stratified analyses and Global Parkinsons Genetics Program (GP2; 34,933 cases/31,009 controls) for sex-combined analyses. Prioritized candidates were further evaluated through MR with brain expression quantitative trait loci (eQTLs) from MetaBrain and differential protein abundance analysis using the Global Neurodegeneration Proteomics Consortium (GNPC; 704 PD cases/5,629 controls in plasma; 78 cases/1,411 controls in cerebrospinal fluid). Additionally, pathway enrichment analysis was performed for prioritized molecules. Integration across three analytical layers prioritized 102 molecular candidates across 31 unique loci, significant from multiple analyses. Of these, eleven genes reached significance across all three layers, including SNCA, MAPT, and CTSB significant in both sexes; CD160, GPNMB, and LRRC37A2 as male-predominant; STX4 and PRSS53 as female-predominant; and BST1, SCARB2, and LGALS3 significant only in sex-combined analysis. In males, CD160 emerged as a novel candidate with convergent evidence across all three analyses and colocalization, while L3MBTL2 was identified as a novel risk gene from gene-based association and TWAS analyses. In females, STX4 and PRSS53 at the 16p11.2 locus showed female-predominant associations. Pathway enrichment analysis revealed innate immune and SUMOylation pathways in males, with CD160 and L3MBTL2 as key contributors respectively, contrasting with WDR5-mediated chromatin remodeling in females. Brain eQTL-based MR confirmed significant associations for 69 of 86 testable candidates (80.2%) in at least one tissue. Protein abundance analysis confirmed sex-specific patterns, and several candidates showed discordant directions between genetically predicted causal effects and observed protein abundance -- including male-specific plasma elevation of CD160 and female-specific patterns for STX4 -- underscoring the distinction between causal risk mechanisms and disease-state molecular changes. These findings demonstrate that PD is a molecularly heterogeneous disorder with sexually dimorphic pathogenic drivers. While shared axes such as lysosomal dysfunction and vesicle trafficking disruption exist, the divergence into male-specific immune dysregulation and female-specific chromatin remodeling suggests that the primary triggers of neurodegeneration differ by sex. Our results underscore the necessity of sex-stratified approaches in biomarker discovery and the development of precision therapeutic strategies for PD.

Microglia are the resident immune cells of the central nervous system and play key roles in the healthy brain during development and adulthood, as well as during neurodegenerative diseases - including Parkinsons disease (PD). Yet the role of microglia in PD pathogenesis has not been fully elucidated. Limitations of 2D cell culture and animal models in simulating human microglia in the brain parenchyma have contributed to this knowledge gap. Human midbrain organoids (hMOs) provide a promising model that can recapitulate elements of PD pathology but lack microglial cells. Here we adapt protocols for the differentiation of hMOs and human iPSC-derived microglia (iMG) to generate iMG-hMO assembloids. Within assembloids, integrated iMG (intMG) express canonical microglia markers and induce the release of cytokines and chemokines. Transcriptomic profiling by single cell RNA sequencing reveals that intMG adopt a more mature and inflammation-responsive state compared to 2D iMG. The integration of microglia results in increased signaling through inflammatory and trophic pathways that drive altered transcriptional signatures of dopaminergic neurons and astrocytes within assembloids. Overall, iMG-hMO assembloids have the potential to more faithfully model the role of microglia and neuroinflammation in PD pathogenesis.

BackgroundContinuous subcutaneous foslevodopa/foscarbidopa infusion (LDp/CDp-CSI) is an effective treatment for patients with Parkinsons disease (PD), but infusion-site nodules are a major cause of treatment discontinuation. Systemic inflammation can influence local skin tolerance; however, predictive biomarkers remain unidentified. ObjectiveTo evaluate the predictive value of the neutrophil-to-lymphocyte ratio (NLR) for clinically significant infusion-site nodules (PD-CSN) during LDp/CDp-CSI and to establish a clinical management framework to mitigate their development. MethodsWe prospectively followed 38 patients with PD initiating LDp/CDp-CSI for [≥]3 months. Baseline immunological data were collected before infusion. A subset of 30 patients was followed for an average of 11 months to identify factors associated with skin nodules at longer follow-up. Nodules were classified by blinded raters. Between-group comparisons, ANCOVA, ROC curve, and Kaplan-Meier analyses were performed. ResultsAt 3 months, 42% of patients were PD-CSN and showed higher baseline neutrophil counts (P=0.030) and NLR (P=0.007), with NLR remaining independently associated with nodule status (F=7.06, P=0.012). ROC analysis demonstrated acceptable discrimination (AUC=0.73, P=0.016). At last follow-up, lower baseline lymphocyte counts (P=0.002) and higher NLR (P=0.001) were observed in PD-CSN. High baseline NLR predicted earlier nodule onset (P=0.001). Despite frequent nodules, multidisciplinary team surveillance, including remote and in-person follow-up, limited treatment discontinuation to 5.3%. ConclusionsBaseline systemic inflammation, reflected by NLR, predicts both the onset and persistence of infusion-site nodules during LDp/CDp-CSI. NLR may serve as a clinically accessible biomarker for early risk stratification. Multidisciplinary surveillance facilitates timely nodule management and enhances treatment adherence.

Deep Brain Stimulation (DBS) is an effective therapy for Parkinson's disease (PD), but clinical programming of stimulation parameters remains a time-consuming process largely guided by subjective symptom assessment. The increasing availability of sensing-enabled neurostimulators and wearable motion sensors provides an opportunity to introduce objective biomarkers into DBS titration. In this work, we present DBSgram, a multimodal framework designed to support data-driven DBS programming by integrating neurophysiological and kinematic measurements acquired during routine clinical titration. The proposed system combines subthalamic nucleus local field potential (STN-LFP) recordings from sensing-enabled neurostimulators with hand kinematic data acquired using wearable inertial measurement units (IMUs). A two-stage synchronization strategy aligns independent data streams from implanted and wearable devices, followed by automated signal processing pipelines for extracting electrophysiological and motor biomarkers. Patient-specific beta-band power is derived from LFP recordings, while tremor, rigidity, and bradykinesia metrics are computed from multi-axis IMU signals using symptom-specific processing algorithms. These synchronized features are then integrated into the DBSgram visualization framework, which maps stimulation amplitude to simultaneous changes in neural activity and objective motor performance. The framework was implemented in a standardized 40-minute clinical titration protocol conducted in a cohort of 18 PD patients implanted with sensing-enabled DBS systems. We present here the analysis of aligned multimodal datasets from different patients to demonstrate proof-of-concept feasibility. The resulting DBSgram visualizations capture stimulation-dependent suppression of pathological beta activity alongside quantitative motor improvements, enabling intuitive identification of patient-specific therapeutic windows. These results demonstrate the technical feasibility of integrating implanted neurophysiological recordings with wearable kinematic sensing during DBS programming. By providing synchronized physiological and motor biomarkers within a unified framework, the DBSgram approach may support more objective and data-driven DBS titration, and contribute to future closed-loop neuromodulation strategies.