RAB39B gene mutations are not a common cause of Parkinson's disease or dementia with Lewy bodies.
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SUBMITTER: Hodges K
PROVIDER: S-EPMC5954832 | biostudies-literature | 2016 Sep
REPOSITORIES: biostudies-literature
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RAB39B gene mutations are not a common cause of Parkinson's disease or dementia with Lewy bodies.
Hodges Kyndall K Brewer Sheridan S SS Labbé Catherine C Soto-Ortolaza Alexandra I AI Walton Ronald L RL Strongosky Audrey J AJ Uitti Ryan J RJ van Gerpen Jay A JA Ertekin-Taner Nilüfer N Kantarci Kejal K Lowe Val J VJ Parisi Joseph E JE Savica Rodolfo R Graff-Radford Jonathan J Jones David T DT Knopman David S DS Petersen Ronald C RC Murray Melissa E ME Graff-Radford Neill R NR Ferman Tanis J TJ Dickson Dennis W DW Wszolek Zbigniew K ZK Boeve Bradley F BF Ross Owen A OA Lorenzo-Betancor Oswaldo O
Neurobiology of aging 20160324
Mutations in Ras-related protein Rab-39B (RAB39B) gene have been linked to X-linked early-onset Parkinsonism with intellectual disabilities. The aim of this study was to address the genetic contribution of RAB39B to Parkinson's disease (PD), dementia with Lewy bodies (DLB), and pathologically confirmed Lewy body dementia (pLBD) cases. A cohort of 884 PD, 399 DLB, and 379 pLBD patients were screened for RAB39B mutations, but no coding variants were found, suggesting RAB39B mutations are not a com ...[more]
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| S-EPMC5318291 | biostudies-literature
Project description:Loss of function mutations within the vesicular trafficking protein Ras analogy in brain 39B (RAB39B) are associated with rare X-linked Parkinson's disease (PD). Physiologically, RAB39B is localized to Golgi vesicles and recycling endosomes and is required for glutamatergic receptor maturation but also for alpha-Synuclein (aSyn) homeostasis and the inhibition of its aggregation. Despite evidence linking RAB39B to neurodegeneration, the involvement of the protein in idiopathic neurodegenerative diseases remains undetermined. Here, analysis of the spatial distribution and expression of RAB39B was conducted in post-mortem human brain tissue from cases of dementia with Lewy bodies (DLB, n = 10), Alzheimer's disease (AD, n = 12) and controls (n = 12). Assessment of cortical RAB39B immunoreactivity using tissue microarrays revealed an overall reduction in the area of RAB39B positive gray matter in DLB cases when compared to controls and AD cases. Strikingly, RAB39B co-localized with beta-amyloid (Aβ) plaques in all cases examined and was additionally present in a subpopulation of Lewy bodies (LBs) in DLB. Biochemical measures of total RAB39B levels within the temporal cortex were unchanged between DLB, AD and controls. However, upon subcellular fractionation, a reduction of RAB39B in the cytoplasmic pool was found in DLB cases, alongside an increase of phosphorylated aSyn and Aβ in whole tissue lysates. The reduction of cytoplasmic RAB39B is consistent with an impaired reserve capacity for RAB39B-associated functions, which in turn may facilitate LB aggregation and synaptic impairment. Collectively, our data support the involvement of RAB39B in the pathogenesis of DLB and the co-aggregation of RAB39B with Aβ in plaques suggests that age-associated cerebral Aβ pathology may be contributory to the loss of RAB39B. Thus RAB39B, its associated functional pathways and its entrapment in aggregates may be considered as future targets for therapeutic interventions to impede the overall pathological burden and cellular dysfunction in Lewy body diseases.
| S-EPMC8018064 | biostudies-literature
Project description: Not available
| S-EPMC8985413 | biostudies-literature
Project description:BACKGROUND:We evaluated the effects of low doses of the tyrosine kinase Abelson (Abl) inhibitor Nilotinib, on safety and pharmacokinetics in Parkinson's disease dementia or dementia with Lewy bodies. OBJECTIVES:The primary outcomes of this study were safety and tolerability; pharmacokinetics and target engagement were secondary, while clinical outcomes were exploratory. METHODS:Twelve subjects were randomized into 150?mg (n?=?5) or 300?mg (n?=?7) groups and received Nilotinib orally every day for 24 weeks. RESULTS:This study shows that 150?mg and 300?mg doses of Nilotinib appear to be safe and tolerated in subjects with advanced Parkinson's disease. Nilotinib is detectable in the cerebrospinal fluid (CSF) and seems to engage the target Abl. Motor and cognitive outcomes suggest a possible beneficial effect on clinical outcomes. The CSF levels of homovanillic acid are significantly increased between baseline and 24 weeks of treatment. Exploratory CSF biomarkers were measured. CONCLUSIONS:This small proof-of-concept study lacks a placebo group and participants were not homogenous, resulting in baseline differences between and within groups. This limits the interpretations of the biomarker and clinical data, and any conclusions should be drawn cautiously. Nonetheless, the collective observations suggest that it is warranted to evaluate the safety and efficacy of Nilotinib in larger randomized, double-blind, placebo-controlled trials.
| S-EPMC5008228 | biostudies-literature
Project description:Neuronal loss in specific brain regions and neurons with intracellular inclusions termed Lewy bodies are the pathologic hallmark in both Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Lewy bodies comprise of aggregated intracellular vesicles and proteins and α-synuclein is reported to be a major protein component. Using human brain tissue from control, PD and DLB and light and confocal immunohistochemistry with antibodies to superoxide dismutase 2 as a marker for mitochondria, α-synuclein for Lewy bodies and βIII Tubulin for microtubules we have examined the relationship between Lewy bodies and mitochondrial loss. We have shown microtubule regression and mitochondrial and nuclear degradation in neurons with developing Lewy bodies. In PD, multiple Lewy bodies were often observed with α-synuclein interacting with DNA to cause marked nuclear degradation. In DLB, the mitochondria are drawn into the Lewy body and the mitochondrial integrity is lost. This work suggests that Lewy bodies are cytotoxic. In DLB, we suggest that microtubule regression and mitochondrial loss results in decreased cellular energy and axonal transport that leads to cell death. In PD, α-synuclein aggregations are associated with intact mitochondria but interacts with and causes nuclear degradation which may be the major cause of cell death.
| S-EPMC8029402 | biostudies-literature
Project description:IntroductionThe understanding of survival in dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD) is limited, as well as the impact of these diagnoses in an ageing co-morbid population.MethodsA retrospective study of 177 patients who received a DLB or PDD diagnosis between 1997-2014 at the Memory Clinic in Malmö, Sweden. Relative survival was evaluated by adjusting all-cause survival for expected survival, estimated from population life-tables, matched by sex, age and calendar year. Predictors of relative survival were investigated using multivariate regression modelling.ResultsAt follow-up, 143 (81%) patients were deceased with a median survival of 4.1 years (IQR 2.6-6.0). After 10-years follow-up, the standardized mortality ratio was 3.44 (95% CI 2.92-4.04). Relative survival was worse with younger age at diagnosis (excess hazard ratio [eHR] 0.91, 95% CI 0.88-0.94 per year of age), female sex (eHR 1.45, 95% CI 1.01-2.09) and lower mini-mental state examination (eHR 0.93, 95% CI 0.90-0.96). Subgroup analysis (n = 141) showed higher mortality in DLB patients who were positive for APOE ɛ4 (eHR 2.00, 95% CI 1.35-2.97).ConclusionThe mortality is over three-times higher in patients diagnosed with dementia with Lewy bodies and Parkinson's disease dementia during a ten-year follow-up, compared to persons in the general population. Excess mortality is found primarily in younger patients, females and carriers of APOE ε4. Further research is needed regarding survival and possible interventions, including disease-modifying treatments, to improve care for this patient group.
| S-EPMC6086429 | biostudies-literature
Project description:As the differential diagnosis of dementias based on established clinical criteria is often difficult, biomarkers for applicable diagnostic testing are currently under intensive investigation. Amyloid plaques deposited in the brain of patients suffering from Alzheimer's disease, dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD) mainly consist of carboxy-terminally elongated forms of amyloid-beta (Abeta) peptides, such as Abeta1-42. Absolute Abeta1-42 levels in CSF have shown diagnostic value for the diagnosis of Alzheimer's disease, but the discrimination among Alzheimer's disease, DLB and PDD was poor. A recently established quantitative urea-based Abeta-sodium-dodecylsulphate-polyacrylamide-gel-electrophoresis with Western immunoblot (Abeta-SDS-PAGE/immunoblot) revealed a highly conserved Abeta peptide pattern of the carboxy-terminally truncated Abeta peptides 1-37, 1-38, 1-39 in addition to 1-40 and 1-42 in human CSF. We used the Abeta-SDS-PAGE/immunoblot to investigate the CSF of 23 patients with Alzheimer's disease, 21 with DLB, 21 with PDD and 23 non-demented disease controls (NDC) for disease-specific alterations of the Abeta peptide patterns in its absolute and relative quantities. The diagnostic groups were matched for age and severity of dementia. The present study is the first attempt to evaluate the meaning of Abeta peptide patterns in CSF for differential diagnosis of the three neurodegenerative diseases--Alzheimer's disease, DLB and PDD. The Abeta peptide patterns displayed disease-specific variations and the ratio of the differentially altered Abeta1-42 to the Abeta1-37 levels subsequently discriminated all diagnostic groups from each other at a highly significant level, except DLB from PDD. Additionally, a novel peptide with Abeta-like immunoreactivity was observed constantly in the CSF of all 88 investigated patients. The pronounced percentage increase of this peptide in DLB allowed a highly significant discrimination from PDD. Using a cut-off point of 0.954%, this marker yielded a diagnostic sensitivity and specificity of 81 and 71%, respectively. From several lines of indication, we consider this peptide to represent an oxidized alpha-helical form of Abeta1-40 (Abeta1-40*). The increased abundance of Abeta1-40* probably reflects a disease-specific alteration of the Abeta1-40 metabolism in DLB. We conclude that Abeta peptide patterns reflect disease-specific pathophysiological pathways of different dementia syndromes as distinct neurochemical phenotypes. Although Abeta peptide patterns failed to fulfil the requirements for a sole biomarker, their combined evaluation with other biomarkers is promising in neurochemical dementia diagnosis. It is noteworthy that DLB and PDD exhibit distinct clinical temporal courses, despite their similar neuropathological appearance. Their distinct molecular phenotypes support the view of different pathophysiological pathways for each of these neurodegenerative diseases.
| S-EPMC5403412 | biostudies-literature
Project description:Dementia with Lewy bodies (DLB) and Parkinson's disease (PD) are clinically, pathologically and etiologically disorders embedded in the Lewy body disease (LBD) continuum, characterized by neuronal α-synuclein pathology. Rare homozygous and compound heterozygous premature termination codon (PTC) mutations in the Vacuolar Protein Sorting 13 homolog C gene (VPS13C) are associated with early-onset recessive PD. We observed in two siblings with early-onset age (< 45) and autopsy confirmed DLB, compound heterozygous missense mutations in VPS13C, p.Trp395Cys and p.Ala444Pro, inherited from their healthy parents in a recessive manner. In lymphoblast cells of the index patient, the missense mutations reduced VPS13C expression by 90% (p = 0.0002). Subsequent, we performed targeted resequencing of VPS13C in 844 LBD patients and 664 control persons. Using the optimized sequence kernel association test, we obtained a significant association (p = 0.0233) of rare VPS13C genetic variants (minor allele frequency ≤ 1%) with LBD. Among the LBD patients, we identified one patient with homozygous missense mutations and three with compound heterozygous missense mutations in trans position, indicative for recessive inheritance. In four patients with compound heterozygous mutations, we were unable to determine trans position. The frequency of LBD patient carriers of proven recessive compound heterozygous missense mutations is 0.59% (5/844). In autopsy brain tissue of two unrelated LBD patients, the recessive compound heterozygous missense mutations reduced VPS13C expression. Overexpressing of wild type or mutant VPS13C in HeLa or SH-SY5Y cells, demonstrated that the mutations p.Trp395Cys or p.Ala444Pro, abolish the endosomal/lysosomal localization of VPS13C. Overall, our data indicate that rare missense mutations in VPS13C are associated with LBD and recessive compound heterozygous missense mutations might have variable effects on the expression and functioning of VPS13C. We conclude that comparable to the recessive inherited PTC mutations in VPS13C, combinations of rare recessive compound heterozygous missense mutations reduce VPS13C expression and contribute to increased risk of LBD.
| S-EPMC7881566 | biostudies-literature
Project description:Swallowing dysfunction is an increasingly recognized problem in patients with dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD), which can result in aspiration pneumonia and death. Few studies have examined potential ways of improving swallowing function in this fragile patient group. The aim of this study was to evaluate swallowing dysfunction and carbonated liquid using videofluoroscopy in DLB and PDD patients.A total of 48 patients with DLB and PDD were referred for a clinical examination with videofluoroscopy. Descriptive overall assessments were provided at the time of the examination regarding swallowing function and the effects of different modifications, including carbonated thin liquid (CTL). Additionally, a repeated measures quantitative retrospective analysis has been performed comparing 1) thin liquids; 2) thickened liquids and 3) CTLs, with regard to the quantitative variables 1) pharyngeal transit time (PTT); 2) pharyngeal retention and 3) tracheal penetration.In all, 40/48 (83%) of the patients had a swallowing dysfunction, which was confirmed on videofluoroscopy, with 34/40 (85%) patients having a pharyngeal-type dysfunction. A total of 14/40 (35%) patients with an objective swallowing impairment did not have any subjective swallowing symptoms. Out of the patients with swallowing dysfunction, 87% had an overall improved swallowing function with carbonated liquid. PTT for carbonated liquid (median 633 ms, interquartile range [IQR] 516-786 ms) was quicker than for thin liquid (760 ms, IQR 613-940 ms, P=0.014) and thickened liquid (880.0 ms, IQR 600-1,500 ms, P<0.001). No significant effect was seen in residue or penetration.The majority of patients with DLB or PDD had a swallowing dysfunction, sometimes without subjective swallowing symptoms, which improved with carbonated liquid. This highlights the importance of investigating patients with videofluoroscopy and to carry out a prospective interventional study to further evaluate carbonated liquid, also addressing the effects on quality of life, aspiration and mortality.
| S-EPMC5557100 | biostudies-literature
Project description:Mixed pathologies of α-synuclein, β-amyloid and tau are relatively common in Parkinson's disease (PD) and Dementia with Lewy Bodies (DLB). We therefore wanted to study the retention patterns of 18F-AV-1451 in PD, PD-dementia (PDD), and DLB. To do this 44 healthy controls, 11 non-demented patients with PD, 18 patients with PDD, and six patients with DLB underwent MRI and 18F-AV-1451 PET scanning and cognitive testing. We found that parietal 18F-AV-1451 retention was increased in patients with DLB compared to controls and PD patients, while 18F-AV-1451 uptake was reduced in the substantia nigra in PDD. Increased parietal 18F-AV-1451 PET uptake was associated with impaired performance on verbal fluency tests, and the decreased uptake in the substantia nigra correlated with worse motor function. We found no effect of the monoamine oxidase B inhibitor rasagiline on 18F-AV-1451 binding. In conclusion DLB patients have increased parietal 18F-AV-1451 uptake. Increased parietal tau is associated with executive impairment in patients with synucleinopathies, while decreased uptake in the substantia nigra is associated with parkinsonism. Further, our data indicate that 18F-AV-1451 does not significantly bind to MAO-B in vivo.
| S-EPMC5856779 | biostudies-literature