CSF Proteomics in Patients With Progressive Supranuclear Palsy.

BACKGROUND AND OBJECTIVES: Identification of fluid biomarkers for progressive supranuclear palsy (PSP) is critical to enhance therapeutic development. We implemented unbiased DNA aptamer (SOMAmer) proteomics to identify novel CSF PSP biomarkers. METHODS: This is a cross-sectional study in original (18 clinically diagnosed PSP-Richardson syndrome [PSP-RS], 28 cognitively healthy controls]), validation (23 PSP-RS, 26 healthy controls), and neuropathology-confirmed (21 PSP, 52 non-PSP frontotemporal lobar degeneration) cohorts. Participants were recruited through the University of California, San Francisco, and the 4-Repeat Neuroimaging Initiative. The original and neuropathology cohorts were analyzed with the SomaScan platform version 3.0 (5026-plex) and the validation cohort with version 4.1 (7595-plex). Clinical severity was measured with the PSP Rating Scale (PSPRS). CSF proteomic data were analyzed to identify differentially expressed targets, implicated biological pathways using enrichment and weighted consensus gene coexpression analyses, diagnostic value of top targets with receiver-operating characteristic curves, and associations with disease severity with linear regressions. RESULTS: A total of 136 participants were included (median age 70.6 ± 8 years, 68 [50%] women). One hundred fifty-five of 5,026 (3.1%), 959 of 7,595 (12.6%), and 321 of 5,026 (6.3%) SOMAmers were differentially expressed in PSP compared with controls in original, validation, and neuropathology-confirmed cohorts, with most of the SOMAmers showing reduced signal (83.1%, 95.1%, and 73.2%, respectively). Three coexpression modules were associated with PSP across cohorts: (1) synaptic function/JAK-STAT (ß = -0.044, corrected p = 0.002), (2) vesicle cytoskeletal trafficking (ß = 0.039, p = 0.007), and (3) cytokine-cytokine receptor interaction (ß = -0.032, p = 0.035) pathways. Axon guidance was the top dysregulated pathway in PSP in original (strength = 1.71, p < 0.001), validation (strength = 0.84, p < 0.001), and neuropathology-confirmed (strength = 0.78, p < 0.001) cohorts. A panel of axon guidance pathway proteins discriminated between PSP and controls in original (area under the curve [AUC] = 0.924), validation (AUC = 0.815), and neuropathology-confirmed (AUC = 0.932) cohorts. Two inflammatory proteins, galectin-10 and cytotoxic T lymphocyte-associated protein-4, correlated with PSPRS scores across cohorts. DISCUSSION: Axon guidance pathway proteins and several other molecular pathways are downregulated in PSP, compared with controls. Proteins in these pathways may be useful targets for biomarker or therapeutic development.

Association of CSF α-Synuclein Seeding Amplification Assay Results With Clinical Features of Possible and Probable Dementia With Lewy Bodies.

BACKGROUND AND OBJECTIVES: The clinical diagnosis of dementia with Lewy bodies (DLB) depends on identifying significant cognitive decline accompanied by core features of parkinsonism, visual hallucinations, cognitive fluctuations, and REM sleep behavior disorder (RBD). Hyposmia is one of the several supportive features. α-Synuclein seeding amplification assays (αSyn-SAAs) may enhance diagnostic accuracy by detecting pathologic αSyn seeds in CSF. In this study, we examine how different clinical features associate with CSF αSyn-SAA positivity in a large group of clinically diagnosed participants with DLB. METHODS: Cross-sectional and longitudinal CSF samples from the multicentered observational cohort study of the DLB Consortium and similar studies within the Parkinson's Disease Biomarker Program, contributed by academic medical centers in the United States, underwent αSyn-SAA testing. Participants included those clinically diagnosed with DLB and 2 control cohorts. Associations between core DLB features and olfaction with αSyn-SAA positivity were evaluated using logistic regression. RESULTS: CSF samples from 191 participants diagnosed with DLB (mean age 69.9 ± 6.8, 15% female), 50 age-matched and sex-matched clinical control participants, and 49 younger analytical control participants were analyzed. Seventy-two percent (137/191) of participants with DLB had positive αSyn-SAAs vs 4% of the control groups. Among participants with DLB, those who were αSyn-SAA-positive had lower Montreal Cognitive Assessment scores (18.8 ± 5.7 vs 21.2 ± 5.2, p = 0.01), had worse parkinsonism on the Movement Disorders Society Unified Parkinson's Disease Rating Scale part III (33.8 ± 15.1 vs 25.6 ± 16.4, p = 0.001), were more likely to report RBD (114/133 [86%] vs 33/53 [62%], p < 0.0001), and had worse hyposmia on the University of Pennsylvania Smell Identification Test (UPSIT) (94/105 [90%] below 15th percentile vs 14/44 [32%], p < 0.0001). UPSIT percentile had the highest area under the curve (0.87, 95% CI 0.81-0.94) in predicting αSyn-SAA positivity and participants scoring at or below the 15th percentile of age and sex normative values had 18.3 times higher odds (95% CI 7.52-44.6) of having a positive αSyn-SAA test. Among 82 participants with longitudinal CSF samples, 81 (99%) had the same αSyn-SAA result for initial and follow-up specimens. DISCUSSION: A substantial proportion of clinically diagnosed participants with DLB had negative αSyn-SAA results. Hyposmia was the strongest clinical predictor of αSyn-SAA positivity. Hyposmia and αSyn-SAA may have utility in improving the diagnostic assessment of individuals with potential DLB. CLASSIFICATION OF EVIDENCE: This study provided Class III evidence that CSF αSyn-SAA distinguishes patients with clinically diagnosed DLB from normal controls.

High baseline perivascular space volume in basal ganglia is associated with attention and executive function decline in Parkinson's disease.

BACKGROUND: Pathologic perivascular spaces (PVS), the fluid-filled compartments surrounding brain vasculature, may underlie cognitive decline in Parkinson's disease (PD). However, whether this impacts specific cognitive domains has not been investigated. OBJECTIVES: This study examined the relationship of PVS volume at baseline with domain-specific and global cognitive change over 2 years in PD individuals. METHODS: A total of 39 individuals with PD underwent 3T T1w magnetic resonance imaging to determine PVS volume fraction (PVS volume normalized to total regional volume) within (i) centrum semiovale, (ii) prefrontal white matter (medial orbitofrontal, rostral middle frontal, and superior frontal), and (iii) basal ganglia. A neuropsychological battery included assessment of cognitive domains and global cognitive function at baseline and after 2 years. RESULTS: Higher basal ganglia PVS at baseline was associated with greater decline in attention, executive function, and global cognition scores. CONCLUSIONS: While previous reports have associated elevated PVS volume in the basal ganglia with decline in global cognition in PD, our findings show such decline may affect the attention and executive function domains.

Examining Associations Between Smartphone Use and Clinical Severity in Frontotemporal Dementia: Proof-of-Concept Study.

BACKGROUND: Frontotemporal lobar degeneration (FTLD) is a leading cause of dementia in individuals aged <65 years. Several challenges to conducting in-person evaluations in FTLD illustrate an urgent need to develop remote, accessible, and low-burden assessment techniques. Studies of unobtrusive monitoring of at-home computer use in older adults with mild cognitive impairment show that declining function is reflected in reduced computer use; however, associations with smartphone use are unknown. OBJECTIVE: This study aims to characterize daily trajectories in smartphone battery use, a proxy for smartphone use, and examine relationships with clinical indicators of severity in FTLD. METHODS: Participants were 231 adults (mean age 52.5, SD 14.9 years; n=94, 40.7% men; n=223, 96.5% non-Hispanic White) enrolled in the Advancing Research and Treatment of Frontotemporal Lobar Degeneration (ARTFL study) and Longitudinal Evaluation of Familial Frontotemporal Dementia Subjects (LEFFTDS study) Longitudinal Frontotemporal Lobar Degeneration (ALLFTD) Mobile App study, including 49 (21.2%) with mild neurobehavioral changes and no functional impairment (ie, prodromal FTLD), 43 (18.6%) with neurobehavioral changes and functional impairment (ie, symptomatic FTLD), and 139 (60.2%) clinically normal adults, of whom 55 (39.6%) harbored heterozygous pathogenic or likely pathogenic variants in an autosomal dominant FTLD gene. Participants completed the Clinical Dementia Rating plus National Alzheimer's Coordinating Center Frontotemporal Lobar Degeneration Behavior and Language Domains (CDR+NACC FTLD) scale, a neuropsychological battery; the Neuropsychiatric Inventory; and brain magnetic resonance imaging. The ALLFTD Mobile App was installed on participants' smartphones for remote, passive, and continuous monitoring of smartphone use. Battery percentage was collected every 15 minutes over an average of 28 (SD 4.2; range 14-30) days. To determine whether temporal patterns of battery percentage varied as a function of disease severity, linear mixed effects models examined linear, quadratic, and cubic effects of the time of day and their interactions with each measure of disease severity on battery percentage. Models covaried for age, sex, smartphone type, and estimated smartphone age. RESULTS: The CDR+NACC FTLD global score interacted with time on battery percentage such that participants with prodromal or symptomatic FTLD demonstrated less change in battery percentage throughout the day (a proxy for less smartphone use) than clinically normal participants (P<.001 in both cases). Additional models showed that worse performance in all cognitive domains assessed (ie, executive functioning, memory, language, and visuospatial skills), more neuropsychiatric symptoms, and smaller brain volumes also associated with less battery use throughout the day (P<.001 in all cases). CONCLUSIONS: These findings support a proof of concept that passively collected data about smartphone use behaviors associate with clinical impairment in FTLD. This work underscores the need for future studies to develop and validate passive digital markers sensitive to longitudinal clinical decline across neurodegenerative diseases, with potential to enhance real-world monitoring of neurobehavioral change.

Chromogranin A (CgA) Deficiency Attenuates Tauopathy by Altering Epinephrine-Alpha-Adrenergic Receptor Signaling.

Our previous studies have indicated that insulin resistance, hyperglycemia, and hypertension in aged wild-type (WT) mice can be reversed in mice lacking chromogranin-A (CgA-KO mice). These health conditions are associated with a higher risk of Alzheimer's disease (AD). CgA, a neuroendocrine secretory protein has been detected in protein aggregates in the brains of AD patients. Here, we determined the role of CgA in tauopathies, including AD (secondary tauopathy) and corticobasal degeneration (CBD, primary tauopathy). We found elevated levels of CgA in both AD and CBD brains, which were positively correlated with increased phosphorylated tau in the frontal cortex. Furthermore, CgA ablation in a human P301S tau (hTau) transgenic mice (CgA-KO/hTau) exhibited reduced tau aggregation, resistance to tau spreading, and an extended lifespan, coupled with improved cognitive function. Transcriptomic analysis of mice cortices highlighted altered levels of alpha-adrenergic receptors (Adra) in hTau mice compared to WT mice, akin to AD patients. Since CgA regulates the release of the Adra ligands epinephrine (EPI) and norepinephrine (NE), we determined their levels and found elevated EPI levels in the cortices of hTau mice, AD and CBD patients. CgA-KO/hTau mice exhibited reversal of EPI levels in the cortex and the expression of several affected genes, including Adra1 and 2, nearly returning them to WT levels. Treatment of hippocampal slice cultures with EPI or an Adra1 agonist intensified, while an Adra1 antagonist inhibited, tau hyperphosphorylation and aggregation. These findings reveal a critical role of CgA in regulation of tau pathogenesis via the EPI-Adra signaling axis.

Data-driven sequence of cognitive decline in people with Parkinson's disease.

BACKGROUND: Understanding the sequential progression of cognitive impairments in Parkinson's disease (PD) is crucial for elucidating neuropathological underpinnings, refining the assessment of PD-related cognitive decline stages and enhancing early identification for targeted interventions. The first aim of this study was to use an innovative event-based modeling (EBM) analytic approach to estimate the sequence of cognitive declines in PD. The second aim was to validate the EBM by examining associations with EBM-derived individual-specific estimates of cognitive decline severity and performance on independent cognitive screening measures. METHODS: This cross-sectional observational study included 99 people with PD who completed a neuropsychological battery. Individuals were classified as meeting the criteria for mild cognitive impairment (PD-MCI) or subtle cognitive decline by consensus. An EBM was constructed to compare cognitively healthy individuals with those with PD-MCI or subtle cognitive disturbances. Multivariable linear regression estimated associations between the EBM-derived stage of cognitive decline and performance on two independent cognitive screening tests. RESULTS: The EBM estimated that tests assessing executive function and visuospatial ability become abnormal early in the sequence of PD-related cognitive decline. Each higher estimated stage of cognitive decline was associated with approximately 0.24 worse performance on the Dementia Rating Scale (p<0.001) and 0.26 worse performance on the Montreal Cognitive Assessment (p<0.001) adjusting for demographic and clinical variables. CONCLUSION: Findings from this study will have important clinical implications for practitioners, on specific cognitive tests to prioritise, when conducting neuropsychological evaluations with people with PD. Results also highlight the importance of frontal-subcortical system disruption impacting executive and visuospatial abilities.

The relationship between objective and subjective executive function in Parkinson's disease.

INTRODUCTION: Difficulties in executive functioning (EF) are common in PD; however, the relationship between subjective and objective EF is unclear. Understanding this relationship could help guide clinical EF assessment. This study examined the relationship between subjective self-reported EF (SEF) and objective EF (OEF) and predictors of SEF-OEF discrepancies in PD. METHOD: One-hundred and sixteen non-demented PD participants completed measures of OEF (i.e. problem-solving, cognitive flexibility, inhibition, and working memory) and SEF (Frontal Systems Behavior Scale-Self Executive Dysfunction Subscale). Pearson bivariate correlations and linear regressions were performed to examine the relationship between SEF and OEF and the non-motor symptoms (e.g. mood, fatigue), demographic, and PD characteristic (e.g. MCI status) predictors of discrepancies between OEF and SEF (|OEF minus SEF scores|). Correlates of under-, over-, and accurate-reporting were also explored. RESULTS: Greater SEF complaints and worse OEF were significantly associated (ß =.200, p = .009) and 64% of participants accurately identified their level of OEF abilities. Fewer years of education and greater symptoms of depression, anxiety, and fatigue significantly correlated with greater discrepancies between OEF and SEF. Fatigue was the best predictor of EF discrepancy in the overall sample (ß = .281, p = .022). Exploratory analyses revealed apathy and fatigue associated with greater under-reporting, while anxiety associated with greater over-reporting. CONCLUSIONS: SEF and OEF are significantly related in PD. Approximately 64% of non-demented persons with PD accurately reported their EF skill level, while 28% under-reported and 8% over-reported. SEF-OEF discrepancies were predicted by fatigue in the overall sample. Preliminary evidence suggests reduced apathy and fatigue symptoms relate to more under-reporting, while anxiety relates to greater over-reporting. Given the prevalence of these non-motor symptoms in PD, it is important to carefully consider them when assessing EF in PD.

Large-scale network analysis of the cerebrospinal fluid proteome identifies molecular signatures of frontotemporal lobar degeneration.

The pathophysiological mechanisms driving disease progression of frontotemporal lobar degeneration (FTLD) and corresponding biomarkers are not fully understood. We leveraged aptamer-based proteomics (> 4,000 proteins) to identify dysregulated communities of co-expressed cerebrospinal fluid proteins in 116 adults carrying autosomal dominant FTLD mutations (C9orf72, GRN, MAPT) compared to 39 noncarrier controls. Network analysis identified 31 protein co-expression modules. Proteomic signatures of genetic FTLD clinical severity included increased abundance of RNA splicing (particularly in C9orf72 and GRN) and extracellular matrix (particularly in MAPT) modules, as well as decreased abundance of synaptic/neuronal and autophagy modules. The generalizability of genetic FTLD proteomic signatures was tested and confirmed in independent cohorts of 1) sporadic progressive supranuclear palsy-Richardson syndrome and 2) frontotemporal dementia spectrum syndromes. Network-based proteomics hold promise for identifying replicable molecular pathways in adults living with FTLD. 'Hub' proteins driving co-expression of affected modules warrant further attention as candidate biomarkers and therapeutic targets.

Gene specific effects on brain volume and cognition of TMEM106B in frontotemporal lobar degeneration.

Background and Objectives: TMEM106B has been proposed as a modifier of disease risk in FTLD-TDP, particularly in GRN mutation carriers. Furthermore, TMEM106B has been investigated as a disease modifier in the context of healthy aging and across multiple neurodegenerative diseases. The objective of this study is to evaluate and compare the effect of TMEM106B on gray matter volume and cognition in each of the common genetic FTD groups and in sporadic FTD patients. Methods: Participants were enrolled through the ARTFL/LEFFTDS Longitudinal Frontotemporal Lobar Degeneration (ALLFTD) study, which includes symptomatic and presymptomatic individuals with a pathogenic mutation in C9orf72, GRN, MAPT, VCP, TBK1, TARDBP, symptomatic non-mutation carriers, and non-carrier family controls. All participants were genotyped for the TMEM106B rs1990622 SNP. Cross-sectionally, linear mixed-effects models were fitted to assess an association between TMEM106B and genetic group interaction with each outcome measure (gray matter volume and UDS3-EF for cognition), adjusting for education, age, sex and CDR®+NACC-FTLD sum of boxes. Subsequently, associations between TMEM106B and each outcome measure were investigated within the genetic group. For longitudinal modeling, linear mixed-effects models with time by TMEM106B predictor interactions were fitted. Results: The minor allele of TMEM106B rs1990622, linked to a decreased risk of FTD, associated with greater gray matter volume in GRN mutation carriers under the recessive dosage model. This was most pronounced in the thalamus in the left hemisphere, with a retained association when considering presymptomatic GRN mutation carriers only. The minor allele of TMEM106B rs1990622 also associated with greater cognitive scores among all C9orf72 mutation carriers and in presymptomatic C9orf72 mutation carriers, under the recessive dosage model. Discussion: We identified associations of TMEM106B with gray matter volume and cognition in the presence of GRN and C9orf72 mutations. This further supports TMEM106B as modifier of TDP-43 pathology. The association of TMEM106B with outcomes of interest in presymptomatic GRN and C9orf72 mutation carriers could additionally reflect TMEM106B's impact on divergent pathophysiological changes before the appearance of clinical symptoms.

Biosensor Strip for Rapid On-site Assessment of Levodopa Pharmacokinetics along with Motor Performance in Parkinson's Disease.

While levodopa (L-Dopa) is the primary treatment for alleviating Parkinson's disease (PD), its efficacy is hindered by challenges such as a short half-life and inconsistent plasma levels. As PD progresses, the rising need for increased and more frequent L-Dopa doses coupled with symptom fluctuations and dyskinesias underscores the urgency for improved comprehension of the interplay between L-Dopa levels and PD motor symptoms. Addressing this critical need, we present a decentralized testing method using a disposable biosensor strip and a universal slope (U-slope) calibration-free approach. This enables reliable, rapid, simple, and cost-effective decentralized L-Dopa measurements from capillary blood. A pilot study with PD persons demonstrates the ability to monitor real-time L-Dopa pharmacokinetics from fingerstick blood after oral L-Dopa-Carbidopa (C-Dopa) tablet administration. Correlating capillary blood L-Dopa levels with PD motor scores revealed a well-defined inverse correlation with temporal motor fluctuations. We compared the resulting dynamic capillary blood L-Dopa levels with plasma L-Dopa levels using the traditional but clinically impractical high-performance liquid chromatography technique. By providing timely feedback on a proper L-Dopa dosing regimen in a decentralized and rapid fashion, this new biosensing platform will facilitate tailored optimal L-Dopa dosing, towards improving symptom management and enhancing health-related quality of life.

Evaluating the Effect of Alzheimer's Disease-Related Biomarker Change in Corticobasal Syndrome and Progressive Supranuclear Palsy.

OBJECTIVES: To evaluate the effect of Alzheimer's disease (AD) -related biomarker change on clinical features, brain atrophy and functional connectivity of patients with corticobasal syndrome (CBS) and progressive supranuclear palsy (PSP). METHODS: Data from patients with a clinical diagnosis of CBS, PSP, and AD and healthy controls were obtained from the 4-R-Tauopathy Neuroimaging Initiative 1 and 2, the Alzheimer's Disease Neuroimaging Initiative, and a local cohort from the Toronto Western Hospital. Patients with CBS and PSP were divided into AD-positive (CBS/PSP-AD) and AD-negative (CBS/PSP-noAD) groups based on fluid biomarkers and amyloid PET scans. Cognitive, motor, and depression scores; AD fluid biomarkers (cerebrospinal p-tau, t-tau, and amyloid-beta, and plasma ptau-217); and neuroimaging data (amyloid PET, MRI and fMRI) were collected. Clinical features, whole-brain gray matter volume and functional networks connectivity were compared across groups. RESULTS: Data were analyzed from 87 CBS/PSP-noAD and 23 CBS/PSP-AD, 18 AD, and 30 healthy controls. CBS/PSP-noAD showed worse performance in comparison to CBS/PSP-AD in the PSPRS [mean(SD): 34.8(15.8) vs 23.3(11.6)] and the UPDRS scores [mean(SD): 34.2(17.0) vs 21.8(13.3)]. CBS/PSP-AD demonstrated atrophy in AD signature areas and brainstem, while CBS/PSP-noAD patients displayed atrophy in frontal and temporal areas, globus pallidus, and brainstem compared to healthy controls. The default mode network showed greatest disconnection in CBS/PSP-AD compared with CBS/PSP-no AD and controls. The thalamic network connectivity was most affected in CBS/PSP-noAD. INTERPRETATION: AD biomarker positivity may modulate the clinical presentation of CBS/PSP, with evidence of distinctive structural and functional brain changes associated with the AD pathology/co-pathology. ANN NEUROL 2024;96:99-109.

Reliability and Validity of Smartphone Cognitive Testing for Frontotemporal Lobar Degeneration.

Importance: Frontotemporal lobar degeneration (FTLD) is relatively rare, behavioral and motor symptoms increase travel burden, and standard neuropsychological tests are not sensitive to early-stage disease. Remote smartphone-based cognitive assessments could mitigate these barriers to trial recruitment and success, but no such tools are validated for FTLD. Objective: To evaluate the reliability and validity of smartphone-based cognitive measures for remote FTLD evaluations. Design, Setting, and Participants: In this cohort study conducted from January 10, 2019, to July 31, 2023, controls and participants with FTLD performed smartphone application (app)-based executive functioning tasks and an associative memory task 3 times over 2 weeks. Observational research participants were enrolled through 18 centers of a North American FTLD research consortium (ALLFTD) and were asked to complete the tests remotely using their own smartphones. Of 1163 eligible individuals (enrolled in parent studies), 360 were enrolled in the present study; 364 refused and 439 were excluded. Participants were divided into discovery (n = 258) and validation (n = 102) cohorts. Among 329 participants with data available on disease stage, 195 were asymptomatic or had preclinical FTLD (59.3%), 66 had prodromal FTLD (20.1%), and 68 had symptomatic FTLD (20.7%) with a range of clinical syndromes. Exposure: Participants completed standard in-clinic measures and remotely administered ALLFTD mobile app (app) smartphone tests. Main Outcomes and Measures: Internal consistency, test-retest reliability, association of smartphone tests with criterion standard clinical measures, and diagnostic accuracy. Results: In the 360 participants (mean [SD] age, 54.0 [15.4] years; 209 [58.1%] women), smartphone tests showed moderate-to-excellent reliability (intraclass correlation coefficients, 0.77-0.95). Validity was supported by association of smartphones tests with disease severity (r range, 0.38-0.59), criterion-standard neuropsychological tests (r range, 0.40-0.66), and brain volume (standardized ß range, 0.34-0.50). Smartphone tests accurately differentiated individuals with dementia from controls (area under the curve [AUC], 0.93 [95% CI, 0.90-0.96]) and were more sensitive to early symptoms (AUC, 0.82 [95% CI, 0.76-0.88]) than the Montreal Cognitive Assessment (AUC, 0.68 [95% CI, 0.59-0.78]) (z of comparison, -2.49 [95% CI, -0.19 to -0.02]; P = .01). Reliability and validity findings were highly similar in the discovery and validation cohorts. Preclinical participants who carried pathogenic variants performed significantly worse than noncarrier family controls on 3 app tasks (eg, 2-back ß = -0.49 [95% CI, -0.72 to -0.25]; P < .001) but not a composite of traditional neuropsychological measures (ß = -0.14 [95% CI, -0.42 to 0.14]; P = .32). Conclusions and Relevance: The findings of this cohort study suggest that smartphones could offer a feasible, reliable, valid, and scalable solution for remote evaluations of FTLD and may improve early detection. Smartphone assessments should be considered as a complementary approach to traditional in-person trial designs. Future research should validate these results in diverse populations and evaluate the utility of these tests for longitudinal monitoring.

Association of Structural Forms of 17q21.31 with the Risk of Progressive Supranuclear Palsy and MAPT Sub-haplotypes.

Importance: The chromosome 17q21.31 region, containing a 900 Kb inversion that defines H1 and H2 haplotypes, represents the strongest genetic risk locus in progressive supranuclear palsy (PSP). In addition to H1 and H2, various structural forms of 17q21.31, characterized by the copy number of α, ß, and γ duplications, have been identified. However, the specific effect of each structural form on the risk of PSP has never been evaluated in a large cohort study. Objective: To assess the association of different structural forms of 17q.21.31, defined by the copy numbers of α, ß, and γ duplications, with the risk of PSP and MAPT sub-haplotypes. Design setting and participants: Utilizing whole genome sequencing data of 1,684 (1,386 autopsy confirmed) individuals with PSP and 2,392 control subjects, a case-control study was conducted to investigate the association of copy numbers of α, ß, and γ duplications and structural forms of 17q21.31 with the risk of PSP. All study subjects were selected from the Alzheimer's Disease Sequencing Project (ADSP) Umbrella NG00067.v7. Data were analyzed between March 2022 and November 2023. Main outcomes and measures: The main outcomes were the risk (odds ratios [ORs]) for PSP with 95% CIs. Risks for PSP were evaluated by logistic regression models. Results: The copy numbers of α and ß were associated with the risk of PSP only due to their correlation with H1 and H2, while the copy number of γ was independently associated with the increased risk of PSP. Each additional duplication of γ was associated with 1.10 (95% CI, 1.04-1.17; P = 0.0018) fold of increased risk of PSP when conditioning H1 and H2. For the H1 haplotype, addition γ duplications displayed a higher odds ratio for PSP: the odds ratio increases from 1.21 (95%CI 1.10-1.33, P = 5.47 × 10-5) for H1ß1γ1 to 1.29 (95%CI 1.16-1.43, P = 1.35 × 10-6) for H1ß1γ2, 1.45 (95%CI 1.27-1.65, P = 3.94 × 10-8) for H1ß1γ3, and 1.57 (95%CI 1.10-2.26, P = 1.35 × 10-2) for H1ß1γ4. Moreover, H1ß1γ3 is in linkage disequilibrium with H1c (R2 = 0.31), a widely recognized MAPT sub-haplotype associated with increased risk of PSP. The proportion of MAPT sub-haplotypes associated with increased risk of PSP (i.e., H1c, H1d, H1g, H1o, and H1h) increased from 34% in H1ß1γ1 to 77% in H1ß1γ4. Conclusions and relevance: This study revealed that the copy number of γ was associated with the risk of PSP independently from H1 and H2. The H1 haplotype with more γ duplications showed a higher odds ratio for PSP and were associated with MAPT sub-haplotypes with increased risk of PSP. These findings expand our understanding of how the complex structure at 17q21.31 affect the risk of PSP.

PINK1 is a target of T cell responses in Parkinson's disease.

Parkinson's disease (PD) is associated with autoimmune T cells that recognize the protein alpha-synuclein in a subset of individuals. Multiple neuroantigens are targets of autoinflammatory T cells in classical central nervous system autoimmune diseases such as multiple sclerosis (MS). Here, we explored whether additional autoantigenic targets of T cells in PD. We generated 15-mer peptide pools spanning several PD-related proteins implicated in PD pathology, including GBA, SOD1, PINK1, parkin, OGDH, and LRRK2. Cytokine production (IFNγ, IL-5, IL-10) against these proteins was measured using a fluorospot assay and PBMCs from patients with PD and age-matched healthy controls. This approach identified unique epitopes and their HLA restriction from the mitochondrial-associated protein PINK1, a regulator of mitochondrial stability, as an autoantigen targeted by T cells. The T cell reactivity was predominantly found in male patients with PD, which may contribute to the heterogeneity of PD. Identifying and characterizing PINK1 and other autoinflammatory targets may lead to antigen-specific diagnostics, progression markers, and/or novel therapeutic strategies for PD.

Genetic analysis of the X chromosome in people with Lewy body dementia nominates new risk loci.

Sex influences the prevalence and symptoms of Lewy body dementia (LBD). However, genome-wide association studies typically focus on autosomal variants and exclude sex-specific risk factors. We addressed this gap by performing an X chromosome-wide association study using whole-genome sequence data from 2591 LBD cases and 4391 controls. We identified a significant risk locus within intron 1 of MAP3K15 (rs141773145, odds ratio = 2.42, 95% confidence interval = 1.65-3.56, p-value = 7.0 × 10-6) in female LBD cases conditioned for APOE ε4 dosage. The locus includes an enhancer region that regulates MAP3K15 expression in ganglionic eminence cells derived from primary cultured neurospheres. Rare variant burden testing showed differential enrichment of missense mutations in TEX13A in female LBD cases, that did not reach significance (p-value = 1.34 × 10-4). These findings support the sex-specific effects of genetic factors and a potential role of Alzheimer's-related risk for females with LBD.

Sex differences for clinical correlates of substantia nigra neuron loss in people with Lewy body pathology.

BACKGROUND: Lewy body dementia (LBD) phenotype is associated with the presence and degree of Lewy body, Alzheimer's pathologies, and substantia nigra neuron loss. Nigral neuron loss is associated with parkinsonism in LBD, and females with LBD are less likely than males to have parkinsonism. As sex differences were reported for clinical correlates of Lewy body and Alzheimer's pathologies, we aimed to investigate whether there are also sex differences for correlates of nigral neuron loss. METHODS: Data were obtained from the National Alzheimer's Coordinating Center for females (n = 159) and males (n = 263) with brainstem, limbic, and neocortical Lewy body pathology. Sex differences for the nigral neuron loss' association with Lewy body pathology staging and core clinical LBD features (cognitive fluctuations, visual hallucinations, rapid eye movement sleep behavior disorder, parkinsonism) during follow-up were analyzed with generalized linear models adjusting for age and Alzheimer's pathology staging. Whether any of the core clinical features at the time of dementia onset can predict underlying nigral neuron loss for females and males were also analyzed with generalized linear models. RESULTS: Compared to males, females died older and had higher levels of Braak tau staging, but had similar levels of Lewy body pathology staging and nigral neuron loss. Females were less likely than males to have a clinical Lewy body disease diagnosis during follow-up. More advanced Lewy body pathology staging was associated with more nigral neuron loss, more so for males than females. More nigral neuron loss was associated with parkinsonism and clinical LBD diagnosis during follow-up, more so for males than females. Across the subgroup with dementia (40 females, 58 males), core LBD features at first visit with dementia were not associated with nigral neuron loss. CONCLUSIONS: Nigral neuron loss' association with Lewy body pathology staging and core LBD features can differ by sex. Compared to males, females with Lewy body pathology have a higher risk of underdiagnosis. There is a need to elucidate the mechanisms underlying sex differences for pathology and clinicopathological correlations to advance diagnostic and therapeutic efforts in LBD.

Lewy body dementia (LBD) is the third most common dementia associated with Lewy body pathology, Alzheimer's pathology, and substantia nigra loss. It is often less recognized in females compared to males, because the typical symptoms are less evident in females. In this study, we investigated whether substantia nigra neuron loss plays a role in the atypical presentation of LBD in females, contributing to the underdiagnosis compared to males. We analyzed data from 159 females and 263 males with pathological Lewy body disease obtained from the National Alzheimer's Coordinating Center. Females tended to be older at the time of death and had more tau buildup, but similar levels of Lewy body pathology and substantia nigra neuron loss compared to males. When we compared males and females of similar age with similar levels of Alzheimer's pathology, we observed that females had less substantia nigra neuron loss at less advanced Lewy body pathology stages. Greater nigral neuron loss was associated with parkinsonism and the typical LBD symptoms in males, but not as strongly in females. The extent of nigral loss could not be predicted based on the clinical features at the time of dementia diagnosis. Thus, the relationship between nigral neuron loss and the LBD symptoms seems to vary by sex. Females with underlying Lewy body disease are more likely to be underdiagnosed compared to males. We need further work to understand why these sex differences exist and how we can better identify and treat LBD.

Whole-Genome Sequencing Analysis Reveals New Susceptibility Loci and Structural Variants Associated with Progressive Supranuclear Palsy.

Background: Progressive supranuclear palsy (PSP) is a rare neurodegenerative disease characterized by the accumulation of aggregated tau proteins in astrocytes, neurons, and oligodendrocytes. Previous genome-wide association studies for PSP were based on genotype array, therefore, were inadequate for the analysis of rare variants as well as larger mutations, such as small insertions/deletions (indels) and structural variants (SVs). Method: In this study, we performed whole genome sequencing (WGS) and conducted association analysis for single nucleotide variants (SNVs), indels, and SVs, in a cohort of 1,718 cases and 2,944 controls of European ancestry. Of the 1,718 PSP individuals, 1,441 were autopsy-confirmed and 277 were clinically diagnosed. Results: Our analysis of common SNVs and indels confirmed known genetic loci at MAPT, MOBP, STX6, SLCO1A2, DUSP10, and SP1, and further uncovered novel signals in APOE, FCHO1/MAP1S, KIF13A, TRIM24, TNXB, and ELOVL1. Notably, in contrast to Alzheimer's disease (AD), we observed the APOE ε2 allele to be the risk allele in PSP. Analysis of rare SNVs and indels identified significant association in ZNF592 and further gene network analysis identified a module of neuronal genes dysregulated in PSP. Moreover, seven common SVs associated with PSP were observed in the H1/H2 haplotype region (17q21.31) and other loci, including IGH, PCMT1, CYP2A13, and SMCP. In the H1/H2 haplotype region, there is a burden of rare deletions and duplications (P = 6.73×10-3) in PSP. Conclusions: Through WGS, we significantly enhanced our understanding of the genetic basis of PSP, providing new targets for exploring disease mechanisms and therapeutic interventions.