Interrelations of Alzheimer´s disease candidate biomarkers neurogranin, fatty acid-binding protein 3 and ferritin to neurodegeneration and neuroinflammation.

There is growing evidence that promising biomarkers of inflammation in Alzheimer´s disease (AD) and other neurodegenerative diseases correlate strongest to levels of tau or neurofilament, indicating an inflammatory response to neuronal damage or death. To test this hypothesis, we investigated three AD candidate markers (ferritin, fatty acid binding protein 3 (FABP-3), and neurogranin) in interrelation to established AD and inflammatory protein markers. We further aimed to determine if such interrelations would be evident in pathological subjects only or also under non-pathological circumstances. Cerebrospinal fluid levels of the three proteins were quantified in samples from the University Clinic of Bonn (UKB) Department of Neurodegenerative Diseases & Geriatric Psychiatry, Germany. Data were analyzed based on clinical or biomarker-defined stratification of subjects with adjustment for covariates age, sex, and APOE status. Levels of ferritin, FABP-3 and neurogranin were elevated in subjects with pathological levels of t-tau independent of beta-amyloid status. The three markers correlated with each other, tau isoforms, age, and those inflammatory markers previously described as related to neurodegeneration, predominantly sTREM2, macrophage migration inhibitory factor, soluble vascular endothelial growth factor receptor, soluble vascular cell adhesion molecule 1 (sVCAM-1), and C1q. These interrelations existed in subjects with pathological and sub-pathological tau levels, in particular for FABP-3 and neurogranin. Relations to ferritin were independent of absolute levels of tau, too, but showed differing trajectories between pathological and non-pathological subjects. A specific set of inflammatory markers is highly related to markers of neuronal damage such as tau, neurogranin, or FABP-3. These proteins could be used as readouts of the inflammatory response during the neurodegeneration phase of AD.

Multicenter Alzheimer's and Parkinson's disease immune biomarker verification study.

INTRODUCTION: Multiple immunity biomarkers have been suggested as tracers of neuroinflammation in neurodegeneration. This study aimed to verify findings in cerebrospinal fluid (CSF) samples of Alzheimer's disease (AD) and Parkinson's disease (PD) subjects from the network of the European, Innovative Medicines Initiative-funded project AETIONOMY. METHODS: A total of 227 samples from the studies/centres AETIONOMY, ICEBERG, and IDIBAPS were used to analyse 21 selected immunity biomarkers in CSF. Results were compared to data of an independent cohort of 399 subjects previously published. RESULTS: Immunity markers were predominantly and reproducibly associated with pathological levels of tau isoforms, but also with amyloid levels, aging, sex, APOE genotype, and center-specific factors. DISCUSSION: Immunity biomarker levels in CSF reflect molecular and cellular pathology rather than diagnosis in neurodegenerative disorders. Assay standardization and stratification for age and other covariates could improve the power of such markers in clinical applications or intervention studies targeting immune responses in neurodegeneration.

Study of LRRK2 variation in tauopathy: Progressive supranuclear palsy and corticobasal degeneration.

BACKGROUND: Mutations in the leucine-rich repeat kinase 2 gene (LRRK2) are the most common genetic cause of Parkinson's disease (PD). Unexpectedly, tau pathology has been reported in a subset of LRRK2 mutation carriers. METHODS: To estimate the frequency of pathogenic LRRK2 mutations and to evaluate the association of common LRRK2 variants with risk of primary tauopathies, we studied 1039 progressive supranuclear palsy (PSP) and 145 corticobasal degeneration patients from the Mayo Clinic Florida brain bank and 1790 controls ascertained at Mayo Clinic. Sanger sequencing of LRRK2 exons 30, 31, 35, and 41 was performed in all patients, and genotyping of all 17 known exonic variants with minor allele frequency >0.5% was performed in patients and controls. RESULTS: LRRK2 mutational screening identified 2 known pathogenic mutations (p.G2019S and p.R1441C), each in 1 PSP patient, the novel p.A1413T mutation in a PSP patient and the rare p.R1707K mutation in a corticobasal degeneration patient. Both p.A1413T and p.R1707K mutations were predicted damaging by at least 2 of 3 prediction programs and affect evolutionary conserved sites of LRRK2. Association analysis using common LRRK2 variants only showed nominal association of the p.L153L variant with PSP. CONCLUSIONS: Our study confirms the presence of pathogenic and potentially pathogenic LRRK2 mutations in pathologically confirmed primary tauopathies, albeit with low frequency. In contrast to PD, common LRRK2 variants do not appear to play a major role in determining PSP and corticobasal degeneration risk. © 2016 International Parkinson and Movement Disorder Society.

Genetic Disorders with Tau Pathology: A Review of the Literature and Report of Two Patients with Tauopathy and Positive Family Histories.

BACKGROUND: Tauopathies are a group of neurodegenerative disorders characterized by the pathological accumulation of hyperphosphorylated and insoluble tau protein within neurons and glia. Although most cases are sporadic, hereditary tauopathies have also been reported. SUMMARY: In this article, we review genetic disorders in which tau pathology has been reported and present two novel families with primary tauopathies. Mutations in the microtubule-associated protein tau gene (MAPT) cause a small subset of primary tauopathies. Mutations in 21 other genes and an 18q deletion syndrome have also been reported to be associated with tau pathology reminiscent of Alzheimer's disease, corticobasal degeneration, progressive supranuclear palsy, argyrophilic grain disease or Pick's disease. In 8 of the 21 genes, tau pathology was only seen in cases with some 'specific' mutations. In the remaining genes, tau pathology, often in the form of Alzheimer-type neurofibrillary lesions, was a common finding but was 'not mutation specific'. The probands of the two families were diagnosed with progressive supranuclear palsy based on clinicopathological evaluation. Their family histories were relevant for parkinsonism in 3 siblings of family 1 and 1 brother and the father from family 2, but these were not autopsy-confirmed. DNA from the brains of the probands from these families was screened for MAPT and leucine-rich repeat kinase 2 gene mutations, but no mutations were identified. KEY MESSAGES: MAPT mutations are a cause of familial tauopathies, but other genes have also been associated with tau pathology. Novel genes still await discovery.

A novel tau mutation, p.K317N, causes globular glial tauopathy.

Globular glial tauopathies (GGTs) are 4-repeat tauopathies neuropathologically characterized by tau-positive, globular glial inclusions, including both globular oligodendroglial inclusions and globular astrocytic inclusions. No mutations have been found in 25 of the 30 GGT cases reported in the literature who have been screened for mutations in microtubule associated protein tau (MAPT). In this report, six patients with GGT (four with subtype III and two with subtype I) were screened for MAPT mutations. They included 4 men and 2 women with a mean age at death of 73 years (55-83 years) and mean age at symptomatic onset of 66 years (50-77 years). Disease duration ranged from 5 to 14 years. All were homozygous for the MAPT H1 haplotype. Three patients had a positive family history of dementia, and a novel MAPT mutation (c.951G>C, p.K317N) was identified in one of them, a patient with subtype III. Recombinant tau protein bearing the lysine-to-asparagine substitution at amino acid residue 317 was used to assess functional significance of the variant on microtubule assembly and tau filament formation. Recombinant p.K317N tau had reduced ability to promote tubulin polymerization. Recombinant 3R and 4R tau bearing the p.K317N mutation showed decreased 3R tau and increased 4R tau filament assembly. These results strongly suggest that the p.K317N variant is pathogenic. Sequencing of MAPT should be considered in patients with GGT and a family history of dementia or movement disorder. Since several individuals in our series had a positive family history but no MAPT mutation, genetic factors other than MAPT may play a role in disease pathogenesis.

Botulinum toxin therapy of cervical dystonia: duration of therapeutic effects.

We sought to explore the therapeutic effect of botulinum toxin (BT) therapy by analysing the time between the BT application and the onset of its decrease (treatment duration, TD), the inter-injection interval (II), and the excess time (ET, ET = II-TD). For this we studied 59 patients (37 females, 22 males, age 52.6 ± 10.9 years) with cervical dystonia (CD, Tsui score 9.0 ± 4.1) and BT therapy with Botox(®) and/or Xeomin(®) sequentially. Altogether 1,289 treatment cycles were evaluated. On average 21.8 ± 14.0 (4-66) treatment cycles were recorded for each patient. TD was 11.8 ± 2.7 weeks (7.8 ± 1.4 to 21.0 ± 3.9 weeks), II 15.4 ± 3.4 weeks (11.3 ± 1.3 to 27.8 ± 11.6 weeks) and ET 3.5 ± 2.4 weeks (23% of II). TD and II were stable throughout the treatment course. In 36% of the patients we found TD ≤10 weeks, in 83% TD ≤12 weeks. In 17% of the patients we saw treatment delays due to appointment difficulties, due to the patient's attempts to explore TD or his actual CD severity, from fear of adverse effects or due to psychiatric comorbidity. 19% of the patients showed prolonged treatment effects probably due to CD fluctuations. 0.38% of the injection series produced singular unexplained therapy failure (SUTF). Antibody-induced therapy failure did not occur. TD and II are stable on long-term monitoring. SUTF, treatment delays, and CD fluctuations can occur. 23% of the time patients are treated suboptimally. Our data suggest to reduce II. If II is to be reduced to ≤12 weeks, use of low antigenicity BT drugs might be useful.

An enzyme-linked immunosorbent assay for detection of botulinum toxin-antibodies.

INTRODUCTION: Antibodies against botulinum neurotoxin (BNT-AB) can be detected by the mouse protection assay (MPA), the hemidiaphragm assay (HDA), and by enzyme-linked immunosorbent assays (ELISA). Both MPA and HDA require sacrifice of experimental animals, and they are technically delicate and labor intensive. We introduce a specially developed ELISA for detection of BNT-A-AB and evaluate it against the HDA. METHODS: Thirty serum samples were tested by HDA and by the new ELISA. Results were compared, and receiver operating characteristic analyses were used to optimize ELISA parameter constellation to obtain either maximal overall accuracy, maximal test sensitivity, or maximal test specificity. When the ELISA is optimized for sensitivity, a sensitivity of 100% and a specificity of 55% can be reached. When it is optimized for specificity, a specificity of 100% and a sensitivity of 90% can be obtained. RESULTS: We present an ELISA for BNT-AB detection that can be-for the first time-customized for special purposes. Adjusted for optimal sensitivity, it reaches the best sensitivity of all BNT-AB tests available. CONCLUSIONS: Using the new ELISA together with the HDA as a confirmation test allows testing for BNT-AB in large numbers of patients receiving BT drugs in an economical, fast, and more animal-friendly way.

Botulinum toxin therapy of cervical dystonia: comparing onabotulinumtoxinA (Botox(®)) and incobotulinumtoxinA (Xeomin (®)).

Several botulinum toxin (BT) drugs are licensed for the treatment of cervical dystonia (CD). We wanted to compare the efficacy and the potency labelling of incobotulinumtoxinA (Xeomin(®)) and onabotulinumtoxinA (Botox(®)) by analysing the duration of their therapeutic effect in a cross-over study. For this we studied 40 CD patients (26 females, 14 males, age at therapy onset 52.6 ± 12.0 years, duration of dystonia at therapy onset 10.0 ± 9.2 years, Tsui score 9.1 ± 3.9) who first received Botox(®) and then Xeomin(®) for at least 4 injection series each. BT doses were exchanged based on a 1:1 conversion ratio. Altogether 1,101 treatment cycles were evaluated. For each patient 27.5 ± 13.1 treatment cycles were recorded. Patients received 18.4 ± 12.4 treatment cycles with Botox(®) and 9.2 ± 4.5 with Xeomin(®). The treatment duration (TD) throughout the treatment course was 11.3 ± 1.0 weeks (Botox(®) 11.2 ± 1.1 weeks, Xeomin(®) 11.4 ± 1.3 weeks). The interinjection interval (II) throughout the treatment course was 14.8 ± 1.9 weeks (Botox(®) 14.7 ± 1.6 weeks, Xeomin(®) 15.0 ± 2.2 weeks). The mean difference between Botox(®) and Xeomin(®) was 0.3 weeks for TD (two-sided 95 % confidence interval [-0.3; 0.9]) and 0.5 weeks for II (two-sided 95 % confidence intervals [-0.4; 1.4]). The confidence intervals of both parameters were within the predefined therapeutic equivalence range set to ±1.5 weeks, thus indicating similar efficacy of both BT drugs. Having based the exchange of Botox(®) and Xeomin(®) on a conversion factor of 1:1 our data confirm previous findings of an identical potency labelling of both products, thus allowing comparisons of efficacy, adverse effects and costs.

Inferior Frontal Sulcal Hyperintensities on Brain MRI Are Associated with Amyloid Positivity beyond Age-Results from the Multicentre Observational DELCODE Study.

Inferior frontal sulcal hyperintensities (IFSHs) on fluid-attenuated inversion recovery (FLAIR) sequences have been proposed to be indicative of glymphatic dysfunction. Replication studies in large and diverse samples are nonetheless needed to confirm them as an imaging biomarker. We investigated whether IFSHs were tied to Alzheimer's disease (AD) pathology and cognitive performance. We used data from 361 participants along the AD continuum, who were enrolled in the multicentre DELCODE study. The IFSHs were rated visually based on FLAIR magnetic resonance imaging. We performed ordinal regression to examine the relationship between the IFSHs and cerebrospinal fluid-derived amyloid positivity and tau positivity (Aß42/40 ratio ≤ 0.08; pTau181 ≥ 73.65 pg/mL) and linear regression to examine the relationship between cognitive performance (i.e., Mini-Mental State Examination and global cognitive and domain-specific performance) and the IFSHs. We controlled the models for age, sex, years of education, and history of hypertension. The IFSH scores were higher in those participants with amyloid positivity (OR: 1.95, 95% CI: 1.05-3.59) but not tau positivity (OR: 1.12, 95% CI: 0.57-2.18). The IFSH scores were higher in older participants (OR: 1.05, 95% CI: 1.00-1.10) and lower in males compared to females (OR: 0.44, 95% CI: 0.26-0.76). We did not find sufficient evidence linking the IFSH scores with cognitive performance after correcting for demographics and AD biomarker positivity. IFSHs may reflect the aberrant accumulation of amyloid ß beyond age.

Conflict adaptation and related neuronal processing in Parkinson's disease.

Non-motor symptoms like cognitive impairment are a huge burden for patients with Parkinson's disease. We examined conflict adaptation by using the congruency sequence effect as an index of adaptation in 17 patients with Parkinson's disease and 18 healthy controls with an Eriksen flanker task using functional magnet resonance imaging to reveal possible differences in executive function performance. We observed overall increased response times in patients with Parkinson's disease compared to healthy controls. A flanker interference effect and congruency sequence effect occurred in both groups. A significant interaction of current and previous trial type was revealed, but no effect of response sequence concerning left or right motor responses. Therefore, top-down conflict monitoring processes are likely the main contributors leading to the congruency sequence effect in our paradigm. In both groups incongruent flanker events elicited activation in the middle temporal gyrus, inferior parietal cortex, dorsolateral prefrontal cortex and the insula in contrast to congruent flanker events. A psychophysiological interactions analysis revealed increased functional connectivity of inferior parietal cortex as a seed to the left prefrontal thalamus during incongruent vs. congruent and neutral stimuli in patients with Parkinson's disease that may reflect compensatory facilitating action selection processes. We conclude that patients with Parkinson's disease exhibit conflict adaptation comparable to healthy controls when investigated while receiving their usual medication.

Teaching an old dog new tricks: serum troponin T as a biomarker in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis is a devastating neurodegenerative disease characterized by progressive loss of upper and lower motor neurons. Diagnosis, management and therapeutic trials are hampered by a lack of informative biomarkers. Troponins are components of skeletal and cardiac muscles. Acute elevation of cardiac isoforms of troponin I and T in serum indicates myocardial injury. Case reports suggested that serum levels of cardiac troponin T, but not cardiac troponin I are chronically elevated in myotrophic lateral sclerosis and other neuromuscular disorders. Using standard clinical laboratory methodologies, we studied serum troponin levels in a multicentric cross-sectional cohort of 75 amyotrophic lateral sclerosis patients and 30 Alzheimer's disease controls and 29 healthy controls (DESCRIBE-ALS cohort) and in a real-world cohort of 179 consecutive patients from our amyotrophic lateral sclerosis clinic at the University Hospital Bonn. We found that serum cardiac troponin T is elevated in >60% of amyotrophic lateral sclerosis patients, while cardiac troponin I is always normal. Serum cardiac troponin T levels increase over time and correlate with disease severity as measured with the revised Amyotrophic Lateral Sclerosis Functional Rating Scale score. There was no correlation with the phosphorylated neurofilament heavy chain levels in the cerebrospinal fluid. We propose that cardiac troponin T elevations in amyotrophic lateral sclerosis are of non-cardiac origin and may serve as a proxy of lower motor neuron or skeletal muscle involvement. They potentially help to stratify patients according to lower motoneuron involvement. Further research will determine the biological origin of the cardiac troponin T elevation and its validity as a diagnostic and/or prognostic marker. Our finding also serves as a reminder to interpret cardiac troponin T elevations in patients with neuromuscular diseases with caution.

Longitudinal Neurocognitive and Pulmonological Profile of Long COVID-19: Protocol for the COVIMMUNE-Clin Study.

BACKGROUND: There is a dearth of information about "brain fog," characterized by concentration, word-finding, or memory problems, which has been listed in the new World Health Organization provisional classification "U09.9 Post-COVID-19 Condition." Moreover, the extent to which these symptoms may be associated with neurological, pulmonary, or psychiatric difficulties is unclear. OBJECTIVE: This ongoing cohort study aims to carefully assess neurocognitive function in the context of the neurological, psychiatric, and pulmonary sequelae of SARS-CoV-2 infection among patients with asymptomatic/mild and severe cases of COVID-19 after remission, including actively recruited healthy controls. METHODS: A total of 150 participants will be included in this pilot study. The cohort will comprise patients who tested positive for SARS-CoV-2 infection with either an asymptomatic course or a mild course defined as no symptoms except for olfactory and taste dysfunction (n=50), patients who tested positive for SARS-CoV-2 infection with a severe disease course (n=50), and a healthy control group (n=50) with similar age and sex distribution based on frequency matching. A comprehensive neuropsychological assessment will be performed comprising nuanced aspects of complex attention, including language, executive function, verbal and visual learning, and memory. Psychiatric, personality, social and lifestyle factors, sleep, and fatigue will be evaluated. Brain magnetic resonance imaging, neurological and physical assessment, and pulmonological and lung function examinations (including body plethysmography, diffusion capacity, clinical assessments, and questionnaires) will also be performed. Three visits are planned with comprehensive testing at the baseline and 12-month visits, along with brief neurological and neuropsychological examinations at the 6-month assessment. Blood-based biomarkers of neurodegeneration will be quantified at baseline and 12-month follow-up. RESULTS: At the time of submission, the study had begun recruitment through telephone and in-person screenings. The first patient was enrolled in the study at the beginning of April 2021. Interim data analysis of baseline information is expected to be complete by December 2021 and study completion is expected at the end of December 2022. Preliminary group comparisons indicate worse word list learning, short- and long-delayed verbal recall, and verbal recognition in both patient cohorts compared with those of the healthy control group, adjusted for age and sex. Initial volumetric comparisons show smaller grey matter, frontal, and temporal brain volumes in both patient groups compared with those of healthy controls. These results are quite robust but are neither final nor placed in the needed context intended at study completion. CONCLUSIONS: To the best of our knowledge, this is the first study to include objective and comprehensive longitudinal analyses of neurocognitive sequelae of COVID-19 in an extreme group comparison stratified by disease severity with healthy controls actively recruited during the pandemic. Results from this study will contribute to the nascent literature on the prolonged effects of COVID-19 on neurocognitive performance via our coassessment of neuroradiological, neurological, pulmonary, psychiatric, and lifestyle factors. TRIAL REGISTRATION: International Clinical Trials Registry Platform DRKS00023806; https://trialsearch.who.int/Trial2.aspx?TrialID=DRKS00023806. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/30259.

Botulinum neurotoxin serotype D - A potential treatment alternative for BoNT/A and B non-responding patients.

OBJECTIVES: Botulinum neurotoxin serotypes A and B (BoNT/A & B) are highly effective medicines to treat hyperactive cholinergic neurons. Due to neutralizing antibody formation, some patients may become non-responders. In these cases, the serotypes BoNT/C-G might become treatment alternatives. BoNT/D is genetically least related to BoNT/A & B and thereby circumventing neutralisation in A/B non-responders. We produced BoNT/D and compared its pharmacology with BoNT/A ex vivo in mice tissue and in vivo in human volunteers. METHODS: BoNT/D was expressed recombinantly in E. coli, isolated by chromatography and its ex vivo potency was determined at mouse phrenic nerve hemidiaphragm preparations. Different doses of BoNT/D or incobotulinumtoxinA were injected into the extensor digitorum brevis (EDB) muscles (n = 30) of human volunteers. Their compound muscle action potentials were measured 11 times by electroneurography within 220 days. RESULTS: Despite a 3.7-fold lower ex vivo potency in mice, a 110-fold higher dosage of BoNT/D achieved the same clinical effect as incobotulinumtoxinA while showing a 50% shortened duration of action. CONCLUSIONS: BoNT/D blocks dose-dependently acetylcholine release in human motoneurons upon intramuscular administration, but its potency and duration of action is inferior to approved BoNT/A based drugs. SIGNIFICANCE: BoNT/D constitutes a potential treatment alternative for BoNT/A & B non-responders.

Characterization and clinical use of inflammatory cerebrospinal fluid protein markers in Alzheimer's disease.

BACKGROUND: Neuroinflammation has gained increasing attention as a potential contributing factor in Alzheimer's disease (AD) pathology. A clinical cerebrospinal fluid biomarker capable of monitoring this process during the course of the disease has yet to emerge, chiefly owing to contradictory research findings. In this study, we sought to clarify the utility of inflammatory biomarkers in diagnostic procedures of AD in three steps: (1) to screen for proteins that are robustly detectable in cerebrospinal fluid; (2) based on this analysis, to explore any associations between the analytically robust markers and salient pathological features of AD; and (3) to determine the discriminative power of these markers in the clinical diagnosis of AD. METHODS: From a total of 46 proteins, 15 that were robustly detectable in cerebrospinal fluid were identified. A subsequent analysis of these markers in a cohort of 399 patients (nondemented subjects, patients with mild cognitive impairment [MCI], and patients with AD, supplemented by smaller cohorts of other diseases) was conducted. Fluid biomarker data were related to AD pathology and neuropsychological markers and adjusted for confounders such as age, sex, apolipoprotein E genotype, and biobank storage time. RESULTS: Cerebrospinal fluid levels of C-reactive protein and soluble TREM2 differed between nondemented subjects, patients with MCI, or patients with AD and were associated with amyloid and tau pathology. Several markers were associated with tau pathology only or with other neurodegenerative diseases. Correlations between neuropsychological performance and inflammatory markers were weak, but they were most prominent in AD and for the most challenging cognitive tests. All investigated covariates had significant influence, with varying effects across the markers. Still, none of the markers achieved discriminative power of more than 70% to distinguish between patient groups defined by clinical or neuropathological categories. CONCLUSIONS: Basic analytical considerations proved indispensable for this type of study because only one-third of the tested markers were robustly detectable in cerebrospinal fluid. Detectable inflammatory protein markers were associated in multiple ways with AD pathology. Yet, even significantly associated markers were not powerful enough in terms of effect strength, sensitivity, and specificity, and hence they were not suited for direct use in clinical diagnostic practice. Targets other than those most commonly considered in this field of research might provide results with better clinical applicability.

Epigenome-wide DNA methylation profiling in Progressive Supranuclear Palsy reveals major changes at DLX1.

Genetic, epigenetic, and environmental factors contribute to the multifactorial disorder progressive supranuclear palsy (PSP). Here, we study epigenetic changes by genome-wide analysis of DNA from postmortem tissue of forebrains of patients and controls and detect significant (P < 0.05) methylation differences at 717 CpG sites in PSP vs. controls. Four-hundred fifty-one of these sites are associated with protein-coding genes. While differential methylation only affects a few sites in most genes, DLX1 is hypermethylated at multiple sites. Expression of an antisense transcript of DLX1, DLX1AS, is reduced in PSP brains. The amount of DLX1 protein is increased in gray matter of PSP forebrains. Pathway analysis suggests that DLX1 influences MAPT-encoded Tau protein. In a cell system, overexpression of DLX1 results in downregulation of MAPT while overexpression of DLX1AS causes upregulation of MAPT. Our observations suggest that altered DLX1 methylation and expression contribute to pathogenesis of PSP by influencing MAPT.

Age- and disease-dependent increase of the mitophagy marker phospho-ubiquitin in normal aging and Lewy body disease.

Although exact causes of Parkinson disease (PD) remain enigmatic, mitochondrial dysfunction is increasingly appreciated as a key determinant of dopaminergic neuron susceptibility in both familial and sporadic PD. Two genes associated with recessive, early-onset PD encode the ubiquitin (Ub) kinase PINK1 and the E3 Ub ligase PRKN/PARK2/Parkin, which together orchestrate a protective mitochondrial quality control (mitoQC) pathway. Upon stress, both enzymes cooperatively identify and decorate damaged mitochondria with phosphorylated poly-Ub (p-S65-Ub) chains. This specific label is subsequently recognized by autophagy receptors that further facilitate mitochondrial degradation in lysosomes (mitophagy). Here, we analyzed human post-mortem brain specimens and identified distinct pools of p-S65-Ub-positive structures that partially colocalized with markers of mitochondria, autophagy, lysosomes and/or granulovacuolar degeneration bodies. We further quantified levels and distribution of the 'mitophagy tag' in 2 large cohorts of brain samples from normal aging and Lewy body disease (LBD) cases using unbiased digital pathology. Somatic p-S65-Ub structures independently increased with age and disease in distinct brain regions and enhanced levels in LBD brain were age- and Braak tangle stage-dependent. Additionally, we observed significant correlations of p-S65-Ub with LBs and neurofibrillary tangle levels in disease. The degree of co-existing p-S65-Ub signals and pathological PD hallmarks increased in the pre-mature stage, but decreased in the late stage of LB or tangle aggregation. Altogether, our study provides further evidence for a potential pathogenic overlap among different forms of PD and suggests that p-S65-Ub can serve as a biomarker for mitochondrial damage in aging and disease. ABBREVIATIONS: BLBD: brainstem predominant Lewy body disease; CCCP: carbonyl cyanide m-chlorophenyl hydrazone; DLB: dementia with Lewy bodies; DLBD: diffuse neocortical Lewy body disease; EOPD: early-onset Parkinson disease; GVB: granulovacuolar degeneration body; LB: Lewy body; LBD: Lewy body disease; mitoQC: mitochondrial quality control; nbM: nucleus basalis of Meynert; PD: Parkinson disease; PDD: Parkinson disease with dementia; p-S65-Ub: PINK1-phosphorylated serine 65 ubiquitin; SN: substantia nigra; TLBD: transitional Lewy body disease; Ub: ubiquitin.

Occurrence of Crohn's disease with Parkinson's disease.

We retrospectively investigated the co-occurrence of Crohn's disease in a cohort of 876 patients with Parkinson's disease, based on the observation that LRRK2 is a shared genetic risk factor. We identified 2 patients with Crohn's disease; this number was consistent with the number of cases expected in the general population.

FTDP-17 with Pick body-like inclusions associated with a novel tau mutation, p.E372G.

Mutations in microtubule-associated protein tau gene (MAPT) cause frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17). Here, we describe a patient with FTDP-17 and a novel missense mutation in exon 13 of MAPT, p.E372G. We compare clinicopathologic features of this patient to two previously unreported patients with another exon 13 mutation, p.G389R. The patient with the p.E372G mutation was a 40-year-old man with behavioral variant frontotemporal dementia (bvFTD), who subsequently developed agrammatic speech and parkinsonism. One of the FTDP-17 patients with p.G389R mutation presented at age 24 with agrammatic variant of primary progressive aphasia, and subsequently behavioral dysfunction. The other presented at age 53 with bvFTD, followed by agrammatic speech and corticobasal syndrome. Neuropathologic features of FTDP-17 due to p.E372G were similar to those of p.G389R, including tau-immunoreactive Pick body-like neuronal inclusions and swollen, tapering thread-like processes in white matter immunoreactive for 3-repeat and 4-repeat tau. Biochemical analysis of insoluble tau showed similar isoform compositions in p.E372G and p.G389R. Functional studies of the p.E372G mutation showed marked increase in tau filament formation and its reduced ability to promote microtubule assembly. Together these findings indicate that p.E372G is a pathogenic MAPT mutation that causes FTDP-17 similar to p.G389R.