Análisis de genes situados en el haplotipo H1 de la región 17q21 y de genes involucrados en la fosforilación de "tau" en la parálisis supranuclear progresiva

[spa] INTRODUCCIÓN: La parálisis supranuclear progresiva (PSP) se caracteriza por el depósito anormal de proteína tau hiperfosforilada en ganglios basales y tronco cerebral. Su etiología es desconocida y el único factor de riesgo genético conocido es su asociación con el haplotipo H1, que engloba un conjunto de polimorfismos en la región 17q21 incluyendo el gen tau y genes flanqueantes. Este haplotipo podría actuar modulando la expresión o el "splicing" de tau, pero existen otros genes candidatos importantes para la función neuronal o relacionados con la función de tau como saitohin, NIK y CRHR1 en esta región, o kinasas implicadas en la fosforilación de tau como GSK-3beta, en otras regiones. OBJETIVOS: Investigar el efecto de polimorfismos y mutaciones de los genes saitohin, CRHR1, región 3'-UTR de tau y GSK-3β sobre el riesgo de desarrollar PSP, y analizar la expresión de CRHR1 en el cerebro de pacientes fallecidos con PSP.METODOLOGÍA: Pacientes con criterios de PSP probable y controles sanos reclutados por la Unidad de Trastornos del Movimiento del Hospital Clínic. Se secuenció la región 3'UTR de tau, diseñando primers específicos, y la región codificante de saitohin en 3 PSP y se genotipó el polimorfismo Q7R en 57 PSP y 83 controles usando métodos previamente descritos. Se secuenció la región codificante de NIK en 3 PSP con métodos previamente descritos y se genotipó el polimorfismo 2839G/C en 40 PSP y 35 controles mediante el enzima de restricción HphI. Se cuantificó la expresión génica de CRHR1 en globus pallidus con PCR a tiempo real en 12 PSP, 10 Alzheimer, 5 pacientes con enfermedad cerebrovascular y 6 controles. Se secuenció la región codificante de CRHR1 en 2 PSP y se genotipó el polimorfismo -16C/T en 40 PSP y 51 controles mediante SSCP. Se genotipó el polimorfismo -50T/C de GSK-3beta en 93 PSP y 125 controles. Los análisis estadísticos se hicieron con el programa SPSS 11.5, usando el test chi-cuadrado para comparar las frecuencias genotípicas y alélicas y el test de Kruskal-Wallis para la comparación de los niveles de expresión génica.RESULTADOS: No se hallaron mutaciones en la región 3'-UTR de tau ni en la región codificante de los genes saitohin, NIK y CRHR1. El genotipo QQ de saitohin fue más frecuente en PSP que en controles (91.2% vs 47%) y cosegregaba con el genotipo CC del polimorfismo G(-221)C del promotor de tau. No se hallaron diferencias entre PSP y controles en la frecuencia genotípica del polimorfismo de NIK. La expresión de mRNA de CRHR1 en globus pallidus fue similar en PSP y el resto de sujetos. El genotipo CC del polimorfismo de CRHR1 fue más frecuente en PSP que en controles (80% vs 53%). El genotipo CC del polimorfismo-50 T/C de GSK-3-betafue algo menos frecuente (p=0.048) y el alelo T más frecuente (p=0.033) en PSP que en controles, y no se detectó interacción con el haplotipo H1/H1.CONCLUSIONES: Nuestros resultados no apoyan que la región 3'UTR de tau presente variantes génicas que puedan explicar el riesgo proporcionado por el haplotipo H1 para sufrir PSP. El genotipo QQ de saitohin y el genotipo CC del polimorfismo de CRHR1 están asociados a PSP en nuestra población y forman parte del haplotipo H1. El gen NIK no está incluído en el haplotipo H1 y no incrementa el riesgo de PSP. La ausencia de mutaciones y de alteración en la expresión génica en ganglios basales no apoya un papel funcional del gen CRHR1 en la PSP. El alelo T del polimorfismo -50T/C GSK-3β está sobrerepresentado en PSP y podría ser un factor de riesgo adicional independiente del haplotipo H1; alternativamente, el genotipo CC podría ser un factor protector.[eng] Progressive supranuclear palsy (PSP) is characterised by abnormal deposition of hyperphosphorylated tau protein in basal ganglia and brainstem. The only known genetic risk factor is the H1 haplotype in the tau gene region, but there are other candidate genes related to tau or neuronal function like saitohin, NIK and CRHR1 in this region or tau-kinases like GSK-3beta in other regions. The aim of this work was to analyse variations of these genes and CRHR1 brain expression in PSP. Patients and controls were recruited by the Hospital Clínic Movement Disorders Unit. Sequencing of tau-3'UTR region and coding region of saitohin were performed in 3 PSP patients, and the Q7R saitohin polymorphism was genotyped in 57 PSP and 83 controls. The coding region of NIK was sequenced in 3 PSP and the 2839G/C polymorphism was genotyped in 40 PSP and 35 controls. CRHR1 gene expression was quantified in globus pallidus using real-time PCR in 12 PSP, 10 Alzheimer, 5 stroke patients and 6 controls. The coding region of CRHR1 was sequenced in 2 PSP and the -16C/T polymorphism was genotyped in 40 PSP and 51 controls. The GSK-3beta -50T/C polymorphism was genotyped in 83 PSP and 125 controls. Genotype and allelic frequencies were compared using the chi-square test and gene expression levels with the Kruskal-Wallis test. No mutations were found. The saitohin QQ genotype and the CRHR1 CC genotype were more frequent in PSP than in controls (91.2% vs 47%; 80% vs 53%), and the NIK genotype frequencies were similar. CRHR1 mRNA expression in globus pallidus was similar in PSP and the rest of subjects. The T allele of the GSK-3polymorphism was more frequent in PSP than in controls (p=0.033), and no interaction was detected with the H1/H1 haplotype. Our results do not support a role of tau-3'UTR and CRHR1 in PSP. The saitohin and CRHR1 polymorphisms are associated with PSP in the context of the H1 haplotype. The NIK gene is not included in the H1 haplotype and does not increase the risk of PSP. GSK-3β genetic variations could be an additional genetic risk factor indepedent of the H1 haplotype

Comprehensive proteomic profiling of plasma-derived Extracellular Vesicles from dementia with Lewy Bodies patients

Altres ajuts: Grant 201405/10 from Fundació La Marató TV3Proteins and nucleic acids contained in extracellular vesicles (EVs) are considered a feasible source of putative biomarkers for physiological and pathological conditions. Within the nervous system, not only neurons but also other brain cells are able to produce EVs, which have been involved in their physiological processes and also in the development and course of several neurodegenerative diseases. Among these, dementia with Lewy bodies (DLB) is the second cause of dementia worldwide, though most cases are missed or misdiagnosed as Alzheimer's disease (AD) due to the important clinical and pathological overlap between both diseases. In an attempt to find reliable biomarkers for DLB diagnosis, our group characterized the proteome of plasma-derived EVs from DLB patients compared to aged-matched healthy controls (HCs) using two different proteomic LC-MS/MS approaches. Remarkably, we found that gelsolin and butyrylcholinesterase were differentially identified between DLB and HCs. Further validation of these results using conventional ELISA techniques, and including an additional group of AD patients, pointed to decreased levels of gelsolin in plasma-EVs from DLB compared to HCs and to AD samples. Thus, gelsolin may be considered a possible biomarker for the differentiation between DLB and AD

Severe Hyperammonemia In Late-onset Ornithine Transcarbamylase Deficiency Triggered By Steroid Administration

Ornithine transcarbamylase deficiency (OTCD) is a rare X-linked disorder of urea synthesis leading to hyperammonemia. Several late-onset cases have been reported. Undiagnosed and untreated patients are at the risk of death or suffering from irreversible sequelae. We describe a 56-year-old patient who presented with acute encephalopathy after steroid treatment. Hyperammonemia due to OTCD was diagnosed and a mutation was found. This allowed us to diagnose two other family members with unexplained encephalopathy who are now asymptomatic on a low-protein diet. OTCD should be considered in any patient with hyperammonemic encephalopathy and immediate treatment should be given to avoid a fatal outcome. We emphasize the need to examine other family members if the diagnosis is confirmed, in order to prevent further life-threatening episodes of encephalopathy or neonatal coma of newborn

Severe Hyperammonemia in Late-Onset Ornithine Transcarbamylase Deficiency Triggered by Steroid Administration

Ornithine transcarbamylase deficiency (OTCD) is a rare X-linked disorder of urea synthesis leading to hyperammonemia. Several late-onset cases have been reported. Undiagnosed and untreated patients are at the risk of death or suffering from irreversible sequelae. We describe a 56-year-old patient who presented with acute encephalopathy after steroid treatment. Hyperammonemia due to OTCD was diagnosed and a mutation was found. This allowed us to diagnose two other family members with unexplained encephalopathy who are now asymptomatic on a low-protein diet. OTCD should be considered in any patient with hyperammonemic encephalopathy and immediate treatment should be given to avoid a fatal outcome. We emphasize the need to examine other family members if the diagnosis is confirmed, in order to prevent further life-threatening episodes of encephalopathy or neonatal coma of newborn

Exploratory study on microRNA profiles from plasma-derived extracellular vesicles in Alzheimer's disease and dementia with Lewy bodies

Altres ajuts: This work was also supported by the MaratóTV3 grant 201405/10.Because of the increasing life expectancy in our society, aging-related neurodegenerative disorders are one of the main issues in global health. Most of these diseases are characterized by the deposition of misfolded proteins and a progressive cognitive decline. Among these diseases, Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) are the most common types of degenerative dementia. Although both show specific features, an important neuropathological and clinical overlap between them hampers their correct diagnosis. In this work, we identified molecular biomarkers aiming to improve the misdiagnosis between both diseases. Plasma extracellular vesicles (EVs) -from DLB, AD and healthy controls- were isolated using size-exclusion chromatography (SEC) and characterized by flow cytometry, Nanoparticle Tracking Analysis (NTA) and cryo-electron microscopy. Next Generation Sequencing (NGS) and related bibliographic search was performed and a selected group of EV-associated microRNAs (miRNAs) was analysed by qPCR. Results uncovered two miRNAs (hsa-miR-451a and hsa-miR-21-5p) significantly down-regulated in AD samples respect to DLB patients, and a set of four miRNAs (hsa-miR-23a-3p, hsa-miR-126-3p, hsa-let-7i-5p, and hsa-miR-151a-3p) significantly decreased in AD respect to controls. The two miRNAs showing decreased expression in AD in comparison to DLB provided area under the curve (AUC) values of 0.9 in ROC curve analysis, thus suggesting their possible use as biomarkers to discriminate between both diseases. Target gene analysis of these miRNAs using prediction online tools showed accumulation of phosphorylation enzymes, presence of proteasome-related proteins and genes involved in cell death among others. Our data suggest that plasma-EV associated miRNAs may reflect a differential profile for a given dementia-related disorder which, once validated in larger cohorts of patients, could help to improve the differential diagnosis of DLB versus AD. The online version of this article (10.1186/s40035-019-0169-5) contains supplementary material, which is available to authorized users

Expression Levels of an Alpha-Synuclein Transcript in Blood May Distinguish between Early Dementia with Lewy Bodies and Parkinson's Disease

Lewy body diseases (LBD) including dementia with Lewy bodies (DLB) and Parkinson disease (PD) are characterized by alpha-synuclein pathology. DLB is difficult to diagnose and peripheral biomarkers are urgently needed. Therefore, we analyzed the expression of five alpha-synuclein gene (SNCA) transcripts, SNCAtv1, SNCAtv2, SNCAtv3, SNCA126, and SNCA112, in 45 LBD and control temporal cortex samples and in the blood of 72 DLB, 59 PD, and 54 control subjects. The results revealed overexpression of SNCAtv1 and SNCA112 in DLB, and SNCAtv2 in PD temporal cortices. In DLB blood, diminution of all SNCA transcripts was observed. SNCAtv1 and SNCAtv2 were diminished in PD with disease onset before 70 years. SNCAtv3, driven by its own promoter, showed opposite expression in early DLB and PD, suggesting that its amount may be an early, DLB specific biomarker. Correlation between blood transcript levels and disease duration was positive in DLB and negative in PD, possibly reflecting differences in brain alpha-synuclein aggregation rates associated with differences in disease courses. In conclusion, SNCA transcripts showed a disease-specific increase in the brain and were diminished in blood of LBD patients. SNCAtv3 expression was decreased in early DLB and increased in early PD and could be a biomarker for early DLB diagnosis

Severity of Dementia, Anosognosia, and Depression in Relation to the Quality of Life of Patients With Alzheimer Disease: Discrepancies Between Patients and Caregivers

Objective: To investigate the factors associated with discrepancies between patient and caregiver reports of the quality of life of patients (QoLp) with Alzheimer¿s disease (AD). Methods: Cross-sectional analytic study of 141 patients and their caregivers. The instruments used were the Quality of Life in AD (QoL-AD), the Global Deterioration Scale (GDS), the Geriatric Depression Scale (GDS-d) and the Anosognosia Questionnaire¿Dementia (AQ-D). Differences were analyzed according to GDS stage. A linear regression analysis was conducted using the difference between the absolute QoLp scores of patients and caregivers. A cluster analysis involving the patient variables was then performed. Results: The discrepancy between patient and caregiver QoLp ratings increased in line with GDS stages (χ2 (2) = 8.7, p = 0.013). In the regression model (F [7,133] = 16.6, p <0.001; R2 = 0.477), discrepancies in QoLp reports were associated with greater anosognosia, less depression and a better cognitive status in patients, as well as with female gender among caregivers. The cluster analysis showed that patients with the lowest ratings of QoLp had a better cognitive status, more depression and less anosognosia. Conversely, the highest ratings were given by patients with a poorer cognitive status, less depression and greater anosognosia. Conclusions: The factors associated with greater discrepancies between patient and caregiver ratings of QoLp were severity of dementia, anosognosia, depression and cognitive status in patients, and female gender in caregivers. In patients with advanced dementia, greater anosognosia leads to more positive ratings in QoLp and complementary observations are required

Platelet miRNA Biosignature Discriminates between Dementia with Lewy Bodies and Alzheimer’s Disease

Dementia with Lewy bodies (DLB) is one of the most common causes of degenerative dementia, after Alzheimer's disease (AD), and presents pathological and clinical overlap with both AD and Parkinson's disease (PD). Consequently, only one in three DLB cases is diagnosed correctly. Platelets, previously related to neurodegeneration, contain microRNAs (miRNAs) whose analysis may provide disease biomarkers. Here, we profiled the whole platelet miRNA transcriptome from DLB patients and healthy controls. Differentially expressed miRNAs were further validated in three consecutive studies from 2017 to 2019 enrolling 162 individuals, including DLB, AD, and PD patients, and healthy controls. Results comprised a seven-miRNA biosignature, showing the highest diagnostic potential for the differentiation between DLB and AD. Additionally, compared to controls, two miRNAs were down-regulated in DLB, four miRNAs were up-regulated in AD, and two miRNAs were down-regulated in PD. Predictive target analysis identified three disease-specific clusters of pathways as a result of platelet-miRNA deregulation. Our cross-sectional study assesses the identification of a novel, highly specific and sensitive platelet-associated miRNA-based biosignature, which distinguishes DLB from AD

Glucocerebrosidase Mrna Is Diminished In Brain Of Lewy Body Diseases And Changes With Disease Progression In Blood

Parkinson disease (PD) and dementia with Lewy bodies (DLB) are Lewy body diseases characterized by abnormal alpha-synuclein deposits and overlapping pathological features in the brain. Several studies have shown that glucocerebrosidase (GBA) deficiency is involved in the development of LB diseases. Here, we aimed to find out if this deficiency starts at the transcriptional level, also involves alternative splicing, and if GBA expression changes in brain are also detectable in blood of patients with LB diseases. The expression of three GBA transcript variants (GBAtv1, GBAtv2 and GBAtv5) was analyzed in samples from 20 DLB, 25 PD and 17 control brains and in blood of 20 DLB, 26 PD patients and 17 unaffected individuals. Relative mRNA expression was determined by real-time PCR. Expression changes were evaluated by the Delta Delta Ct method. In brain, specific expression profiles were identified in the temporal cortex of DLB and in the caudate nucleus of PD. In blood, significant GBA mRNA diminution was found in both DLB and PD patients. Early PD and early-onset DLB patients showed lowest GBA levels which were normal in PD patients with advanced disease and DLB patients who developed disease after 70 years of age. In conclusion, disease group specific GBA expression profiles were found in mostly affected areas of LBD. In blood, GBA expression was diminished in LB diseases, especially in patients with early onset DLB and in patients with early PD. Age of disease onset exerts an opposite effect on GBA expression in DLB and PD

Efficacy and safety clinical trial with efavirenz in patients diagnosed with adult Niemann-pick type C with cognitive impairment

Background:Niemann-Pick disease Type C (NPC) is a genetic, incurable, neurodegenerative disorder. This orphan disease is most frequently caused by mutations in the NPC1 protein, resulting in intralysossomal cholesterol accumulation. NPC1 is found in neuronal cell bodies, axon terminals and synaptosomes, suggesting it plays a role in lysosomal degradation pathway and in synaptic transmission. Neuronal function is especially vulnerable to NPC1 deficiency and synaptic changes seem a key element in disease development. Currently, Miglustat (Zavesca (R)) is the only approved treatment for NPC. However, preclinical evidence showed that low-dose Efavirenz reverted synaptic defects through pharmacological activation of the enzyme CYP46. Methods:This is a single-center, phase II clinical trial to evaluate the efficacy and safety of Efavirenz in addition to standard of care in patients diagnosed with adult or late juvenile-onset NPC with cognitive impairment. All enrolled patients will be treated orally with 25 mg/d of Efavirenz for 52 weeks (1 year). Secondary objectives include evaluating clinical (neurological and neuropsychological questionnaires) and biological (imaging and biochemical biomarkers) parameters. Discussion:NPC is still an unmet medical need. Although different therapeutic approaches are under study, this is the first clinical trial (to the best of our knowledge) studying the effects of Efavirenz in adult- and late-juvenile-onset NPC. Despite the small sample size and the single-arm design, we expect the results to show Efavirenz's capacity of activating the CYP46 enzyme to compensate for NPC1 deficiency and correct synaptic changes, therefore compensating cognitive and psychiatric changes in these patients. This study may provide direct benefit to enrolled patients in terms of slowing down the disease progression