LATE-NC staging in routine neuropathologic diagnosis: an update.

An international consensus report in 2019 recommended a classification system for limbic-predominant age-related TDP-43 encephalopathy neuropathologic changes (LATE-NC). The suggested neuropathologic staging system and nomenclature have proven useful for autopsy practice and dementia research. However, some issues remain unresolved, such as cases with unusual features that do not fit with current diagnostic categories. The goal of this report is to update the neuropathologic criteria for the diagnosis and staging of LATE-NC, based primarily on published data. We provide practical suggestions about how to integrate available genetic information and comorbid pathologies [e.g., Alzheimer's disease neuropathologic changes (ADNC) and Lewy body disease]. We also describe recent research findings that have enabled more precise guidance on how to differentiate LATE-NC from other subtypes of TDP-43 pathology [e.g., frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS)], and how to render diagnoses in unusual situations in which TDP-43 pathology does not follow the staging scheme proposed in 2019. Specific recommendations are also made on when not to apply this diagnostic term based on current knowledge. Neuroanatomical regions of interest in LATE-NC are described in detail and the implications for TDP-43 immunohistochemical results are specified more precisely. We also highlight questions that remain unresolved and areas needing additional study. In summary, the current work lays out a number of recommendations to improve the precision of LATE-NC staging based on published reports and diagnostic experience.

Temporal Ordering of Inflammatory Analytes sTNFR2 and sTREM2 in Relation to Alzheimer's Disease Biomarkers and Clinical Outcomes.

Inflammatory changes are among the key markers of Alzheimer's disease (AD) related pathological changes. Pro-inflammatory analytes have been related to cognitive decline while others have been related to attenuating neuronal death. Among them, changes in cerebrospinal fluid (CSF) levels of soluble triggering receptor expressed on myeloid cells 2 (sTREM2) and soluble tumor necrosis factor receptor 2 (sTNFR2) have been described as impacting favorable clinical outcomes in AD. We therefore evaluate the effect of CSF sTREM2 and sTNFR2 when taken together on AD biomarkers and longitudinal clinical decline to understand their relative role on impacting AD clinical biomarkers and subsequent clinical outcomes. This longitudinal observational cohort study included 168 amyloid-positive (A+) and p-tau-positive (T+) participants with mild cognitive impairment (MCI) or AD dementia from the Alzheimer's Disease Neuroimaging Initiative (ADNI) with 109 of them having concomitant CSF sTREM2 and sTNFR2 data and 48 A+ T+ participants with MCI from a tertiary memory clinic cohort. An exploratory analysis was performed using data from 86 cognitively normal (CN) participants from ADNI with 72 of them having concomitant CSF AD biomarkers and CSF sTREM2 and sTNFR2 data. General linear models were used to evaluate the effect of sTREM2 and sTNFR2 levels on baseline CSF Aß42, t-tau, and p-tau, and a linear mixed-effects model was used to assess longitudinal cognitive change after controlling for well-known covariates. Among ADNI A+ T+ MCI and AD dementia participants, CSF sTNFR2 had a stronger association, than CSF sTREM2, with CSF t-tau and p-tau. This was replicated among A+ T+ MCI participants from the memory clinic cohort. On the contrary, among A+ T+ CN participants, CSF sTREM2 explained significant variance in CSF t-tau and p-tau, while CSF sTNFR2 did not. When the effects of CSF sTNFR2 and t-tau on longitudinal cognitive change were taken into account, higher CSF sTREM2 predicted slower cognitive decline in A+ T+ AD dementia participants and faster decline in A+ T+ CN participants. Our results show that given the dynamic changes in sTREM2 and sTNFR2, the clinical impact of these distinct inflammation related biomarkers in tracking AD temporal progression across disease stages are likely to differ.

TNFRSF1B Gene Variants and Related Soluble TNFR2 Levels Impact Resilience in Alzheimer's Disease.

Tumor necrosis factor receptor 2 (TNFR2) promotes neuronal survival downstream. This longitudinal study evaluated whether the TNFRSF1B gene encoding TNFR2 and levels of its soluble form (sTNFR2) affect Alzheimer disease (AD) biomarkers and clinical outcomes. Data analyzed included 188 patients in the Alzheimer's Disease Neuroimaging Initiative (ADNI) who had mild cognitive impairment (MCI) and AD dementia. Further, a replication study was performed in 48 patients with MCI with positive AD biomarkers who were treated at a memory clinic. Cerebrospinal fluid (CSF) sTNFR2 levels along with two related TNFRSF1B gene single nucleotide polymorphisms (SNPs) rs976881 and rs1061622 were assessed. General linear models were used to evaluate the effect of CSF sTNFR2 levels and each SNP in relationship to CSF t-tau and p-tau, cognitive domains, MRI brain measures, and longitudinal cognitive changes after adjustments were made for covariates such as APOE ε4 status. In the ADNI cohort, a significant interaction between rs976881 and CSF sTNFR2 modulates CSF t-tau and p-tau levels; hippocampal and whole brain volumes; and Digit Span Forwards subtest scores. In the replication cohort, a significant interaction between rs976881 and CSF sTNFR2 modulates CSF p-tau. A significant interaction between rs976881 and CSF sTNFR2 also impacts Clinical Dementia Rating Sum of Boxes scores over 12 months in the ADNI cohort. The interaction between TNFRSF1B variant rs976881 and CSF sTNFR2 levels was noted to modulate multiple AD-associated severity markers and cognitive domains. This interaction impacts resilience-related clinical outcomes in AD and lends support to sTNFR2 as a promising candidate for therapeutic targeting to improve clinical outcomes of interest.

Fluid and Tissue Biomarkers of Lewy Body Dementia: Report of an LBDA Symposium.

The Lewy Body Dementia Association (LBDA) held a virtual event, the LBDA Biofluid/Tissue Biomarker Symposium, on January 25, 2021, to present advances in biomarkers for Lewy body dementia (LBD), which includes dementia with Lewy bodies (DLBs) and Parkinson's disease dementia (PDD). The meeting featured eight internationally known scientists from Europe and the United States and attracted over 200 scientists and physicians from academic centers, the National Institutes of Health, and the pharmaceutical industry. Methods for confirming and quantifying the presence of Lewy body and Alzheimer's pathology and novel biomarkers were discussed.

Harnessing endophenotypes and network medicine for Alzheimer's drug repurposing.

Following two decades of more than 400 clinical trials centered on the "one drug, one target, one disease" paradigm, there is still no effective disease-modifying therapy for Alzheimer's disease (AD). The inherent complexity of AD may challenge this reductionist strategy. Recent observations and advances in network medicine further indicate that AD likely shares common underlying mechanisms and intermediate pathophenotypes, or endophenotypes, with other diseases. In this review, we consider AD pathobiology, disease comorbidity, pleiotropy, and therapeutic development, and construct relevant endophenotype networks to guide future therapeutic development. Specifically, we discuss six main endophenotype hypotheses in AD: amyloidosis, tauopathy, neuroinflammation, mitochondrial dysfunction, vascular dysfunction, and lysosomal dysfunction. We further consider how this endophenotype network framework can provide advances in computational and experimental strategies for drug-repurposing and identification of new candidate therapeutic strategies for patients suffering from or at risk for AD. We highlight new opportunities for endophenotype-informed, drug discovery in AD, by exploiting multi-omics data. Integration of genomics, transcriptomics, radiomics, pharmacogenomics, and interactomics (protein-protein interactions) are essential for successful drug discovery. We describe experimental technologies for AD drug discovery including human induced pluripotent stem cells, transgenic mouse/rat models, and population-based retrospective case-control studies that may be integrated with multi-omics in a network medicine methodology. In summary, endophenotype-based network medicine methodologies will promote AD therapeutic development that will optimize the usefulness of available data and support deep phenotyping of the patient heterogeneity for personalized medicine in AD.

Key inflammatory pathway activations in the MCI stage of Alzheimer's disease.

OBJECTIVE: To determine the key inflammatory pathways that are activated in the peripheral and CNS compartments at the mild cognitive impairment (MCI) stage of Alzheimer's disease (AD). METHODS: A cross-sectional study of patients with clinical and biomarker characteristics consistent with MCI-AD in a discovery cohort, with replication in the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort. Inflammatory analytes were measured in the CSF and plasma with the same validated multiplex analyte platform in both cohorts and correlated with AD biomarkers (CSF Aß42, total tau (t-tau), phosphorylated tau (p-tau) to identify key inflammatory pathway activations. The pathways were additionally validated by evaluating genes related to all analytes in coexpression networks of brain tissue transcriptome from an autopsy confirmed AD cohort to interrogate if the same pathway activations were conserved in the brain tissue gene modules. RESULTS: Analytes of the tumor necrosis factor (TNF) signaling pathway (KEGG ID:4668) in the CSF and plasma best correlated with CSF t-tau and p-tau levels, and analytes of the complement and coagulation pathway (KEGG ID:4610) best correlated with CSF Aß42 levels. The top inflammatory signaling pathways of significance were conserved in the peripheral and the CNS compartments. They were also confirmed to be enriched in AD brain transcriptome gene clusters. INTERPRETATION: A cell-protective rather than a proinflammatory analyte profile predominates in the CSF in relation to neurodegeneration markers among MCI-AD patients. Analytes from the TNF signaling and the complement and coagulation pathways are relevant in evaluating disease severity at the MCI stage of AD.

Poly(ADP-ribose) drives pathologic α-synuclein neurodegeneration in Parkinson's disease.

The pathologic accumulation and aggregation of α-synuclein (α-syn) underlies Parkinson's disease (PD). The molecular mechanisms by which pathologic α-syn causes neurodegeneration in PD are not known. Here, we found that pathologic α-syn activates poly(adenosine 5'-diphosphate-ribose) (PAR) polymerase-1 (PARP-1), and PAR generation accelerates the formation of pathologic α-syn, resulting in cell death via parthanatos. PARP inhibitors or genetic deletion of PARP-1 prevented pathologic α-syn toxicity. In a feed-forward loop, PAR converted pathologic α-syn to a more toxic strain. PAR levels were increased in the cerebrospinal fluid and brains of patients with PD, suggesting that PARP activation plays a role in PD pathogenesis. Thus, strategies aimed at inhibiting PARP-1 activation could hold promise as a disease-modifying therapy to prevent the loss of dopamine neurons in PD.

DNA methylation of TOMM40-APOE-APOC2 in Alzheimer's disease.

The apolipoprotein E (APOE) ε4 allele is the major genetic risk factor for Alzheimer's disease (AD). Multiple regulatory elements, spanning the extended TOMM40-APOE-APOC2 region, regulate gene expression at this locus. Regulatory element DNA methylation changes occur under different environmental conditions, such as disease. Our group and others have described an APOE CpG island as hypomethylated in AD, compared to cognitively normal controls. However, little is known about methylation of the larger TOMM40-APOE-APOC2 region. The hypothesis of this investigation was that regulatory element methylation levels of the larger TOMM40-APOE-APOC2 region are associated with AD. The aim was to determine whether DNA methylation of the TOMM40-APOE-APOC2 region differs in AD compared to cognitively normal controls in post-mortem brain and peripheral blood. DNA was extracted from human brain (n = 12) and peripheral blood (n = 67). A methylation array was used for this analysis. Percent methylation within the TOMM40-APOE-APOC2 region was evaluated for differences according to tissue type, disease state, AD-related biomarkers, and gene expression. Results from this exploratory analysis suggest that regulatory element methylation levels within the larger TOMM40-APOE-APOC2 gene region correlate with AD-related biomarkers and TOMM40 or APOE gene expression in AD.

Regulatory region genetic variation is associated with FYN expression in Alzheimer's disease.

Neurofibrillary tangles (NFTs), composed of hyperphosphorylated tau, are a key pathologic feature of Alzheimer's disease (AD). Tau phosphorylation is under the control of multiple kinases and phosphatases, including Fyn. Previously, our group found an association between 2 regulatory single nucleotide polymorphisms in the FYN gene with increased tau levels in the cerebrospinal fluid. In this study, we hypothesized that Fyn expression in the brain is influenced by AD status and genetic content. We found that Fyn protein, but not messenger RNA, levels were increased in AD patients compared to cognitively normal controls and are associated with regulatory region single nucleotide polymorphisms. In addition, the expression of the FYN 3'UTR can decrease expression in multiple cell lines, suggesting this regulatory region plays an important role in FYN expression. Taken together, these data suggest that FYN expression is regulated according to AD status and regulatory region haplotype, and genetic variants may be instrumental in the development of neurofibrillary tangles in AD and other tauopathies.

Clinical and imaging characteristics of late onset mitochondrial membrane protein-associated neurodegeneration (MPAN).

Young onset dementias present significant diagnostic challenges. We present the case of a 35-year-old Kuwaiti man with social withdrawal, drowsiness, irritability, anxiety, aphasia, memory loss, hypereflexia, and Parkinsonism. Brain MRI showed bilateral symmetric gradient echo hypointensities in the globi pallidi and substantiae nigrae. Left cortical hypometabolism was seen on brain fluorodeoxyglucose positron emission tomography. A cortical brain biopsy revealed a high Lewy body burden. Genetic testing revealed a homozygous p.T11M mutation in the C19orf12 gene consistent with mitochondrial membrane protein-associated neurodegeneration. This is the oldest onset age of MPAN reported.

Association of Traumatic Brain Injury With Late-Life Neurodegenerative Conditions and Neuropathologic Findings.

IMPORTANCE: The late effects of traumatic brain injury (TBI) are of great interest, but studies characterizing these effects are limited. OBJECTIVE: To determine whether TBI with loss of consciousness (LOC) is associated with an increased risk for clinical and neuropathologic findings of Alzheimer disease (AD), Parkinson disease (PD), and other dementias. DESIGN, SETTING, AND PARTICIPANTS: This study analyzed data from the Religious Orders Study (ROS), Memory and Aging Project (MAP), and Adult Changes in Thought study (ACT). All ROS and MAP participants and a subset of ACT participants consent to autopsy. Studies performed annual (ROS and MAP) or biennial (ACT) cognitive and clinical testing to identify incident cases of dementia and AD. The 7130 participants included members of a Seattle-area health care delivery system (ACT), priests and nuns living in orders across the United States (ROS), and Chicago-area adults in retirement communities (MAP). Of these, 1589 underwent autopsy. Primary hypothesis was that TBI with LOC would be associated with increased risk for AD and neurofibrillary tangles. Data were accrued from 1994 to April 1, 2014. EXPOSURES: Self-reported TBI when the participant was free of dementia, categorized as no more than 1 vs more than 1 hour of LOC. MAIN OUTCOMES AND MEASURES: Clinical outcomes included incident all-cause dementia, AD, and PD in all studies and incident mild cognitive impairment and progression of parkinsonian signs in ROS and MAP. Neuropathologic outcomes included neurofibrillary tangles, neuritic plaques, microinfarcts, cystic infarcts, Lewy bodies, and hippocampal sclerosis in all studies. RESULTS: Of 7130 participants (2879 [40.4%] men; overall mean [SD] age, 79.9 [6.9] years), 865 reported a history of TBI with LOC. In 45 190 person-years of follow-up, 1537 incident cases of dementia and 117 of PD were identified. No association was found between TBI with LOC and incident dementia (ACT: HR for TBI with LOC ≤1 hour, 1.03; 95% CI, 0.83-1.27; HR for TBI with LOC >1 hour, 1.18; 95% CI, 0.77-1.78; ROS and MAP: HR for TBI with LOC ≤1 hour, 0.87; 95% CI, 0.58-1.29; HR for TBI with LOC >1 hour, 0.84; 95% CI, 0.44-1.57) or AD (findings similar to those for dementia). Associations were found for TBI with LOC and incident PD in ACT (HR for TBI with LOC >1 hour, 3.56; 95% CI, 1.52-8.28) and progression of parkinsonian signs in ROS and MAP (odds ratio [OR] for TBI with LOC ≤1 hour, 1.65; 95% CI, 1.23-2.21; OR for TBI with LOC >1 hour, 2.23; 95% CI, 1.16-4.29). Traumatic brain injury with LOC was associated with Lewy bodies (any Lewy body in ACT: RR for TBI with LOC >1 hour, 2.64; 95% CI, 1.40-4.99; Lewy bodies in substantia nigra and/or locus ceruleus in ACT: RR for TBI with LOC >1 hour, 3.30; 95% CI, 1.71-6.38; Lewy bodies in frontal or temporal cortex in ACT: RR for TBI with LOC >1 hour, 5.73; 95% CI, 2.18-15.0; ROS and MAP: RR for TBI with LOC ≤1 hour, 1.64; 95% CI, 1.00-2.70; pooled RR for TBI with LOC ≤1 hour, 1.59; 95% CI, 1.06-2.39) and microinfarcts (any cortical microinfarct in ROS and MAP: RR for TBI with LOC >1 hour, 2.12; 95% CI, 1.12-4.01; pooled RR for TBI with LOC >1 hour, 1.58; 95% CI, 1.06-2.35). CONCLUSIONS AND RELEVANCE: Pooled clinical and neuropathologic data from 3 prospective cohort studies indicate that TBI with LOC is associated with risk for Lewy body accumulation, progression of parkinsonism, and PD, but not dementia, AD, neuritic plaques, or neurofibrillary tangles.

A randomized, double-blind phase I/IIa study of intranasal glutathione in Parkinson's disease.

BACKGROUND: Depletion of reduced glutathione is associated with PD and glutathione augmentation has been proposed as a disease-modifying strategy. The aim of this study was to determine the safety and tolerability of intranasal reduced glutathione in individuals with PD. METHODS: Thirty individuals with PD were randomized to either placebo (saline), 300 mg/day, or 600 mg/day of intranasal glutathione in three divided daily doses. Follow-up visits included side effect screening of PD symptoms and cognition, blood chemistry, sinus irritation, and hyposmia. Tolerability was measured by frequency and severity of reported adverse events, compliance, and withdrawals from the study. RESULTS: After 3 months, there were no substantial differences between groups in the number of adverse events reported or observed among all safety measures assessed. All groups met tolerability criteria. CONCLUSIONS: These data support the safety and tolerability of intranasal glutathione in this population. Pharmacokinetic and dose-finding studies are warranted.

Haptoglobin phenotype modifies serum iron levels and the effect of smoking on Parkinson disease risk.

INTRODUCTION: Haptoglobin is a hemoglobin-binding protein that exists in three functionally different phenotypes, and haptoglobin phenotype 2-1 has previously been associated with Parkinson disease (PD) risk, with mechanisms not elucidated. Some evidence is emerging that low levels of serum iron may increase PD risk. In this study we investigated whether PD patients have lower serum iron and ferritin than controls, and whether this is dependent on haptoglobin phenotype. We also investigated the effect of Hp phenotype as a modifier of the effect of smoking on PD risk. METHODS: The study population consisted of 128 PD patients and 226 controls. Serum iron, ferritin, and haptoglobin phenotype were determined, and compared between PD cases and controls. Stratified analysis by haptoglobin phenotype was performed to determine effect of haptoglobin phenotype on serum iron parameter differences between PD cases and controls and to investigate its role in the protective effect of smoking on PD risk. RESULTS: PD cases had lower serum iron than controls (83.28 ug/100 ml vs 94.00 ug/100 ml, p 0.006), and in particular among subjects with phenotype 2-1. The protective effect of smoking on PD risk resulted stronger in subjects with phenotype 1-1 and 2-2, and weakest among subjects with phenotype 2-1. Ferritin levels were higher in PD cases than controls among subjects of White ethnicity. CONCLUSIONS: Our results report for the first time that the haptoglobin phenotype may be a contributor of iron levels abnormalities in PD patients. The mechanisms for these haptoglobin-phenotype specific effects will have to be further elucidated.

TREM2 deficiency eliminates TREM2+ inflammatory macrophages and ameliorates pathology in Alzheimer's disease mouse models.

Variants in triggering receptor expressed on myeloid cells 2 (TREM2) confer high risk for Alzheimer's disease (AD) and other neurodegenerative diseases. However, the cell types and mechanisms underlying TREM2's involvement in neurodegeneration remain to be established. Here, we report that TREM2 is up-regulated on myeloid cells surrounding amyloid deposits in AD mouse models and human AD tissue. TREM2 was detected on CD45(hi)Ly6C(+) myeloid cells, but not on P2RY12(+) parenchymal microglia. In AD mice deficient for TREM2, the CD45(hi)Ly6C(+) macrophages are virtually eliminated, resulting in reduced inflammation and ameliorated amyloid and tau pathologies. These data suggest a functionally important role for TREM2(+) macrophages in AD pathogenesis and an unexpected, detrimental role of TREM2 in AD pathology. These findings have direct implications for future development of TREM2-targeted therapeutics.

Influence of lifestyle modifications on age-related free radical injury to brain.

IMPORTANCE: The Healthy Brain Initiative 2013-2018 seeks to optimize brain health as we age. Free radical injury is an important effector of molecular and cellular stress in the aging brain that derives from multiple sources. OBJECTIVE: To identify potentially modifiable risk factors associated with increased markers of brain oxidative stress. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional, academic multicenter study consisted of 320 research volunteers (172 women) aged 21 to 100 years who were medically healthy and cognitively normal. MAIN OUTCOMES AND MEASURES: Free radical injury to the brain was assessed using cerebrospinal fluid (CSF) F2-isoprostane (F2-IsoP) concentrations correlated with age, sex, race, cigarette smoking, body mass index, inheritance of the ε4 allele of the apolipoprotein E gene (APOE), and CSF biomarkers of Alzheimer disease. RESULTS: The concentration of CSF F2-IsoP increased with age by approximately 3 pg/mL (approximately 10%) from age 45 to 71 years in medically healthy, cognitively normal adults (P < .001). The CSF F2-IsoP concentration increased by approximately more than 10% for every 5-U increase in body mass index (P < .001). Current smoking had an approximately 3-fold greater effect on CSF F2-IsoPs compared with age (P < .001). Women had greater mean CSF F2-IsoP concentrations than men at all ages after adjusting for other factors (P = .02). Neither the concentration of CSF Alzheimer disease biomarkers nor inheritance of the APOE ε4 allele was associated with the CSF F2-IsoP concentration in this group of medically healthy, cognitively normal adults (P > .05). The association between CSF F2-IsoP concentrations and race was not significant after controlling for the effect of current smoking status (P = .45). CONCLUSIONS AND RELEVANCE: Our results are consistent with an age-related increase in free radical injury in the human brain and uniquely suggest that this form of injury may be greater in women than in men. Our results also highlighted 2 lifestyle modifications (ie, body mass index and smoking) that would have an even greater effect on suppressing free radical injury to the brain than would suppressing the processes of aging. These results inform efforts to achieve success in the Healthy Brain Initiative 2013-2018.

Cheek cell-derived α-synuclein and DJ-1 do not differentiate Parkinson's disease from control.

Recently, α-synuclein (α-syn) and DJ-1, 2 proteins critically involved in Parkinson's disease (PD), have been shown to be present in saliva, suggesting their potential utility as biomarkers of PD. However, the origin and influence of demographic characteristics (e.g., age or sex) on these proteins are unknown. We identified cheek epithelium, which forms the majority of the cellular component of saliva and is readily accessible clinically, as 1 of several potential sources of salivary α-syn and DJ-1. However, no PD-related trend in the cellular component was present. In the supernatant collected from 198 healthy subjects, no correlation was seen between salivary DJ-1 or α-syn with age. When male and female subjects were analyzed separately, a weak age-dependent increase in DJ-1 level was present in male subjects, along with slightly increased α-syn in female subjects. These results, albeit largely negative, provide critical information for understanding the salivary gland pathology and saliva as a PD biomarker source, and must be considered in future investigations of salivary changes in PD.

Pacific Northwest Udall Center of excellence clinical consortium: study design and baseline cohort characteristics.

BACKGROUND: The substantial proportion of individuals with Parkinson's disease (PD) who have or are expected to develop concomitant cognitive impairment emphasizes the need for large, well-characterized participant cohorts to serve as a basis for research into the causes, manifestations, and potential treatments of cognitive decline in those with PD. OBJECTIVE: To establish a multi-site clinical core that cognitively and clinically characterizes patients with PD by obtaining quality longitudinal clinical, neuropsychological, and validated biomarker data. METHODS: Six hundred nineteen participants with idiopathic PD (68.0 ± 9.1 years, 7.1 ± 6.2 years since diagnosis, 70% males) were enrolled in the Pacific Northwest Udall Center (PANUC), one of the Morris K. Udall Centers of Excellence for Parkinson's Research, Clinical Consortium and underwent comprehensive clinical and neuropsychological assessment. Participants were diagnosed with no cognitive impairment (PD-NCI), mild cognitive impairment (PD-MCI), or dementia (PDD) at a diagnostic consensus conference. RESULTS: A substantial proportion of the overall sample was diagnosed with cognitive impairment at baseline: 22% with PDD and 59% with PD-MCI. A higher rate of cognitive impairment was observed in men than women (87% vs. 68%, p < 0.0001), despite a higher level of education. Most patients older than 50 years at the time of diagnosis and with disease duration greater than 10 years were cognitively impaired or demented. CONCLUSIONS: The PANUC Clinical Consortium is a clinically and cognitively well-characterized cohort of patients with PD. Baseline cohort characteristics demonstrate a high rate of cognitive impairment in the sample, as well as potential sex differences with regard to cognitive diagnosis. The PANUC Clinical Consortium, with its access to biomarker, genetic, and autopsy data, provides an excellent foundation for detailed research related to cognitive impairment in PD.

MicroRNA in Alzheimer's disease: an exploratory study in brain, cerebrospinal fluid and plasma.

MicroRNA (miRNA) may be potential biomarkers of Alzheimer's disease (AD). The objective of this investigation was to demonstrate that miRNAs in human brain or biofluids are differentially expressed according to disease status, tissue type, neuritic plaque score or Braak stage. Post-mortem brain (PMB) miRNA were profiled using arrays and validated using quantitative RT-PCR (qRT-PCR). Five qRT-PCR-validated miRNAs were measured in an independent sample of PMB, cerebrospinal fluid and plasma from the same subjects. Plasma miR-15a was found to be associated with plaque score in the independent sample. In conclusion, miRNA present in human biofluids may offer utility as biomarkers of AD.

CDC7 inhibition blocks pathological TDP-43 phosphorylation and neurodegeneration.

OBJECTIVE: Kinase hyperactivity occurs in both neurodegenerative disease and cancer. Lesions containing hyperphosphorylated aggregated TDP-43 characterize amyotrophic lateral sclerosis and frontotemporal lobar degeneration with TDP-43 inclusions. Dual phosphorylation of TDP-43 at serines 409/410 (S409/410) drives neurotoxicity in disease models; therefore, TDP-43-specific kinases are candidate targets for intervention. METHODS: To find therapeutic targets for the prevention of TDP-43 phosphorylation, we assembled and screened a comprehensive RNA interference library targeting kinases in TDP-43 transgenic Caenorhabditis elegans. RESULTS: We show CDC7 robustly phosphorylates TDP-43 at pathological residues S409/410 in C. elegans, in vitro, and in human cell culture. In frontotemporal lobar degeneration (FTLD)-TDP cases, CDC7 immunostaining overlaps with the phospho-TDP-43 pathology found in frontal cortex. Furthermore, PHA767491, a small molecule inhibitor of CDC7, reduces TDP-43 phosphorylation and prevents TDP-43-dependent neurodegeneration in TDP-43-transgenic animals. INTERPRETATION: Taken together, these data support CDC7 as a novel therapeutic target for TDP-43 proteinopathies, including FTLD-TDP and amyotrophic lateral sclerosis.