Network Analysis Identifies SOD2 mRNA as a Potential Biomarker for Parkinson's Disease

Increasing evidence indicates that Parkinson's disease (PD) and type 2 diabetes (T2DM) share dysregulated molecular networks. We identified 84 genes shared between PD and T2DM from curated disease-gene databases. Nitric oxide biosynthesis, lipid and carbohydrate metabolism, insulin secretion and inflammation were identified as common dysregulated pathways. A network prioritization approach was implemented to rank genes according to their distance to seed genes and their involvement in common biological pathways. Quantitative polymerase chain reaction assays revealed that a highly ranked gene, superoxide dismutase 2 (SOD2), is upregulated in PD patients compared to healthy controls in 192 whole blood samples from two independent clinical trials, the Harvard Biomarker Study (HBS) and the Diagnostic and Prognostic Biomarkers in Parkinson's disease (PROBE). The results from this study reinforce the idea that shared molecular networks between PD and T2DM provides an additional source of biologically meaningful biomarkers. Evaluation of this biomarker in de novo PD patients and in a larger prospective longitudinal study is warranted

Beta2-adrenoreceptor agonists and long-term risk of Parkinson's disease

Introduction There is limited information on how the association between Parkinson's disease and the use of beta2-adrenoreceptor (β2AR) agonists varies among groups of short-, long-, and ultra-long-acting β2AR agonists (SABA, LABA and ultraLABA). Methods In this prospective study of the Norwegian population, we estimated the incidence of Parkinson's disease according to exposure to β2AR agonists as a time-dependent variable by means of Cox regression. We adjusted for educational level, comorbidity and performed a sensitivity analysis excluding individuals with chronic obstructive pulmonary disease (COPD), all factors associated with smoking. Anticholinergics and corticosteroids as drugs with the same indication were analyzed for comparison. Results In the follow-up period from 2005 to 2019, 15,807 incident Parkinson's cases were identified. After adjustments for sex, education and age as the timescale, SABA (Hazard ratio (HR) = 0.84; 95%CI: 0.79, 0.89; p < 0.001), LABA (HR = 0.85; 95%CI: 0.81, 0.90; p < 0.001) and ultraLABA (HR = 0.6; 95%CI: 0.49, 0.73; p < 0.001) were all associated with a lower risk of Parkinson's disease. After exclusion of COPD patients, corticosteroids and anticholinergics were no longer inversely associated, whereas β2AR agonists remained associated. Conclusion Of drugs with the same indication of use, only β2AR agonists remained inversely associated with PD risk after all adjustments, with ultraLABA displaying the overall strongest association. Although the precision of the estimate is limited by the modest number of exposed PD cases without COPD, the association is intriguing and suggest that longer-acting, more lipophilic, and thus likely more brain-penetrant β2AR agonists could be prioritized for further studies.publishedVersio

A common polymorphism in SNCA is associated with accelerated motor decline in GBA-Parkinson's disease.

A growing number of genetic susceptibility factors have been identified for Parkinson’s disease (PD). The combination of inherited risk variants is likely to affect not only risk of developing PD but also its clinical course. Variants in the GBA gene are particularly common, being found in approximately 5 to 10% of patients, and they lead to more rapid disease progression1. However, the effect of concomitant genetic risk factors on disease course in GBA-PD is not known.The CamPaIGN study has received financial support from the Wellcome Trust, the Medical Research Council, Parkinson’s UK and the Patrick Berthoud Trust. CHWG is supported by an RCUK/UKRI Innovation Fellowship awarded by the Medical Research Council. RAB is supported by the Wellcome Trust Stem Cell Institute (Cambridge). TBS received financial support from the Cure Parkinson’s Trust. The study is also supported by the National Institute for Health Research (NIHR) Cambridge Biomedical Research Centre Dementia and Neurodegeneration Theme (reference number 146281). The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care. CRS' work is supported in part by NIH grants R01AG057331, U01NS100603, R01AG057331, and the American Parkinson Disease Association. Illumina MEGA Chip genotyping was made possible by a philanthropic investment from Dooley LLC (to Brigham & Women's Hospital and CRS)

Metallothioneins as dynamic markers for brain disease in lysosomal disorders

Objective: To facilitate development of novel disease-modifying therapies for lysosomal storage disorder (LSDs) characterized by nervous system involvement such as metachromatic leukodystrophy (MLD), molecular markers for monitoring disease progression and therapeutic response are needed. To this end, we sought to identify blood transcripts associated with the progression of MLD. Methods: Genome-wide expression analysis was performed in primary T lymphocytes of 24 patients with MLD compared to 24 age- and sex-matched healthy controls. Genes associated with MLD were identified, confirmed on a quantitative polymerase chain reaction platform, and replicated in an independent patient cohort. mRNA and protein expression of the prioritized gene family of metallothioneins was evaluated in postmortem patient brains and in mouse models representing 6 other LSDs. Metallothionein expression during disease progression and in response to specific treatment was evaluated in 1 of the tested LSD mouse models. Finally, a set of in vitro studies was planned to dissect the biological functions exerted by this class of molecules. Results: Metallothionein genes were significantly overexpressed in T lymphocytes and brain of patients with MLD and generally marked nervous tissue damage in the LSDs here evaluated. Overexpression of metallothioneins correlated with measures of disease progression in mice and patients, whereas their levels decreased in mice upon therapeutic treatment. In vitro studies indicated that metallothionein expression is regulated in response to oxidative stress and inflammation, which are biochemical hallmarks of lysosomal storage diseases. Interpretation Metallothioneins are potential markers of neurologic disease processes and treatment response in LSDs

Impact of GBA1 variants on long-term clinical progression and mortality in incident Parkinson’s disease

Funder: Foundation for the National Institutes of Health; FundRef: http://dx.doi.org/10.13039/100000009Funder: Van Geest FoundationFunder: Patrick Berthoud Charitable Trust; FundRef: http://dx.doi.org/10.13039/501100004218Funder: Cure Parkinson's TrustFunder: Michael J Fox FoundationFunder: Innovate UK; FundRef: http://dx.doi.org/10.13039/501100006041Funder: Dooley LLCFunder: American Parkinson's disease associationFunder: Medical Research Council; FundRef: http://dx.doi.org/10.13039/501100000265Funder: Cambridge Centre for Parkinson-PlusFunder: Parkinson's UK; FundRef: http://dx.doi.org/10.13039/501100000304Funder: John Black charitable foundationFunder: Wellcome Trust; FundRef: http://dx.doi.org/10.13039/100004440Funder: National Institute for Health Research; FundRef: http://dx.doi.org/10.13039/501100000272Funder: Van Andel Research Institute; FundRef: http://dx.doi.org/10.13039/100006019Introduction: Variants in the GBA1 gene have been identified as a common risk factor for Parkinson’s disease (PD). In addition to pathogenic mutations (those associated with Gaucher disease), a number of ‘non-pathogenic’ variants also occur at increased frequency in PD. Previous studies have reported that pathogenic variants adversely affect the clinical course of PD. The role of ‘non-pathogenic’ GBA1 variants on PD course is less clear. In this study, we report the effect of GBA1 variants in incident PD patients with long-term follow-up. Methods: The study population consisted of patients in the Cambridgeshire Incidence of Parkinson’s disease from General Practice to Neurologist and Parkinsonism: Incidence, Cognition and Non-motor heterogeneity in Cambridgeshire cohorts. Patients were grouped into non-carriers, carriers of ‘non-pathogenic’ GBA1 variants and carriers of pathogenic GBA1 mutations. Survival analyses for time to development of dementia, postural instability and death were carried out. Cox regression analysis controlling for potential confounders were used to determine the impact of GBA1 variants on these outcome measures. Results: GBA1 variants were identified in 14.4% of patients. Pathogenic and ‘non-pathogenic’ GBA1 variants were associated with the accelerated development of dementia and a more aggressive motor course. Pathogenic GBA1 variants were associated with earlier mortality in comparison with non-carriers, independent of the development of dementia. Discussion: GBA1 variants, including those not associated with Gaucher disease, are common in PD and result in a more aggressive disease course

Plasma-borne indicators of inflammasome activity in Parkinson’s disease patients

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by motor and non-motor symptoms and loss of dopaminergic neurons of the substantia nigra. Inflammation and cell death are recognized aspects of PD suggesting that strategies to monitor and modify these processes may improve the management of the disease. Inflammasomes are pro-inflammatory intracellular pattern recognition complexes that couple these processes. The NLRP3 inflammasome responds to sterile triggers to initiate pro-inflammatory processes characterized by maturation of inflammatory cytokines, cytoplasmic membrane pore formation, vesicular shedding, and if unresolved, pyroptotic cell death. Histologic analysis of tissues from PD patients and individuals with nigral cell loss but no diagnosis of PD identified elevated expression of inflammasome-related proteins and activation-related “speck” formation in degenerating mesencephalic tissues compared with controls. Based on previous reports of circulating inflammasome proteins in patients suffering from heritable syndromes caused by hyper-activation of the NLRP3 inflammasome, we evaluated PD patient plasma for evidence of inflammasome activity. Multiple circulating inflammasome proteins were detected almost exclusively in extracellular vesicles indicative of ongoing inflammasome activation and pyroptosis. Analysis of plasma obtained from a multi-center cohort identified elevated plasma-borne NLRP3 associated with PD status. Our findings are consistent with others indicating inflammasome activity in neurodegenerative disorders. Findings suggest mesencephalic inflammasome protein expression as a histopathologic marker of early-stage nigral degeneration and suggest plasma-borne inflammasome-related proteins as a potentially useful class of biomarkers for patient stratification and the detection and monitoring of inflammation in PD

MHC-I expression renders catecholaminergic neurons susceptible to T-cell-mediated degeneration

Subsets of rodent neurons are reported to express major histocompatibilty complex class I (MHC-I), but such expression has not been reported in normal adult human neurons. Here we provide evidence from immunolabel, RNA expression, and mass spectrometry analysis of postmortem samples that human catecholaminergic substantia nigra and locus coeruleus neurons express MHC-I, and that this molecule is inducible in human stem cell derived dopamine (DA) neurons. Catecholamine murine cultured neurons are more responsive to induction of MHC-I by gamma-interferon than other neuronal populations. Neuronal MHC-I is also induced by factors released from microglia activated by neuromelanin or alpha-synuclein, or high cytosolic DA and/or oxidative stress. DA neurons internalize foreign ovalbumin and display antigen derived from this protein by MHC-I, which triggers DA neuronal death in the presence of appropriate cytotoxic T-cells. Thus, neuronal MHC-I can trigger antigenic response, and catecholamine neurons may be particularly susceptible to T cell-mediated cytotoxic attack

Parkinson's disease biomarkers: perspective from the NINDS Parkinson's Disease Biomarkers Program

Biomarkers for Parkinson's disease (PD) diagnosis, prognostication and clinical trial cohort selection are an urgent need. While many promising markers have been discovered through the National Institute of Neurological Disorders and Stroke Parkinson's Disease Biomarker Program (PDBP) and other mechanisms, no single PD marker or set of markers are ready for clinical use. Here we discuss the current state of biomarker discovery for platforms relevant to PDBP. We discuss the role of the PDBP in PD biomarker identification and present guidelines to facilitate their development. These guidelines include: harmonizing procedures for biofluid acquisition and clinical assessments, replication of the most promising biomarkers, support and encouragement of publications that report negative findings, longitudinal follow-up of current cohorts including the PDBP, testing of wearable technologies to capture readouts between study visits and development of recently diagnosed (de novo) cohorts to foster identification of the earliest markers of disease onset

Lysosomal Dysfunction Promotes Cleavage and Neurotoxicity of Tau In Vivo

Article Number: e1001026Peer reviewe

Specifically neuropathic Gaucher's mutations accelerate cognitive decline in Parkinson's.

OBJECTIVE: We hypothesized that specific mutations in the β-glucocerebrosidase gene (GBA) causing neuropathic Gaucher's disease (GD) in homozygotes lead to aggressive cognitive decline in heterozygous Parkinson's disease (PD) patients, whereas non-neuropathic GD mutations confer intermediate progression rates. METHODS: A total of 2,304 patients with PD and 20,868 longitudinal visits for up to 12.8 years (median, 4.1) from seven cohorts were analyzed. Differential effects of four types of genetic variation in GBA on longitudinal cognitive decline were evaluated using mixed random and fixed effects and Cox proportional hazards models. RESULTS: Overall, 10.3% of patients with PD and GBA sequencing carried a mutation. Carriers of neuropathic GD mutations (1.4% of patients) had hazard ratios (HRs) for global cognitive impairment of 3.17 (95% confidence interval [CI], 1.60-6.25) and a hastened decline in Mini-Mental State Exam scores compared to noncarriers (p = 0.0009). Carriers of complex GBA alleles (0.7%) had an HR of 3.22 (95% CI, 1.18-8.73; p = 0.022). By contrast, the common, non-neuropathic N370S mutation (1.5% of patients; HR, 1.96; 95% CI, 0.92-4.18) or nonpathogenic risk variants (6.6% of patients; HR, 1.36; 95% CI, 0.89-2.05) did not reach significance. INTERPRETATION: Mutations in the GBA gene pathogenic for neuropathic GD and complex alleles shift longitudinal cognitive decline in PD into "high gear." These findings suggest a relationship between specific types of GBA mutations and aggressive cognitive decline and have direct implications for improving the design of clinical trials. Ann Neurol 2016;80:674-685