Locus Coeruleus Pathology Indicates a Continuum of Lewy Body Dementia

2021 ◽  
pp. 1-10
Author(s):  
Bension S. Tilley ◽  
Shivani R. Patel ◽  
Marc H. Goldfinger ◽  
Ronald K.B. Pearce ◽  
Steve M. Gentleman

Background: Lewy body dementia (LBD) has two main phenotypes of LBD, Parkinson’s disease dementia (PDD) and dementia with Lewy bodies (DLB), separated by the ‘one-year-rule’. They also show different symptom profiles: core DLB features include fluctuating cognition, REM-sleep behaviur disorder, and visual hallucinations. These symptoms are sometimes present in PDD, representing an intermediate ‘PDD-DLB’ phenotype. Objective: DLB-like features may reflect deficits in the functions of the noradrenergic nucleus locus coeruleus (LC). Therefore, we compared the LC in the LBD phenotypes, PD, and controls. Methods: 38 PD, 56 PDD, 22 DLB, and 11 age-matched control cases from the Parkinson’s UK tissue bank were included. LC tissue sections were immunostained for tyrosine-hydroxylase (TH), α-synuclein, tau, and amyloid-β. TH-neurons were quantified and pathologic burden calculated by %-coverage method. Results: The LC shows a stepwise reduction in neuron count from controls, PD, PDD, to DLB. PDD-DLB cases showed an intermediate clinical phenotype that was reflected pathologically. Cell counts were significantly reduced in DLB compared to PDD after correction for demographic factors. LC degeneration contributed significantly to the onset of all DLB symptoms. While α-synuclein was not significantly different between PDD and DLB cases, DLB exhibited significantly less tau pathology. Conclusion: DLB and DLB-like symptoms represent noradrenergic deficits resulting from neuronal loss in the LC. PDD and DLB are likely to represent a clinical continuum based on the presence or absence of DLB-like symptoms mirrored by a pathological continuum in the LC.

2021 ◽  
Vol 22 (12) ◽  
pp. 6185
Author(s):  
Jing Xu ◽  
Ichiro Kawahata ◽  
Hisanao Izumi ◽  
Kohji Fukunaga

Lewy bodies are pathological characteristics of Lewy body dementia (LBD) and are composed of α-synuclein (α-Syn), which is mostly degraded via the ubiquitin–proteasome system. More importantly, 26S proteasomal activity decreases in the brain of LBD patients. We recently introduced a T-type calcium channel enhancer SAK3 (ethyl-8-methyl-2,4-dioxo-2-(piperidin-1-yl)- 2H-spiro[cyclopentane-1,3-imidazo [1,2-a]pyridin]-2-ene-3-carboxylate) for Alzheimer’s disease therapeutics. SAK3 enhanced the proteasome activity via CaMKII activation in amyloid precursor protein knock-in mice, promoting the degradation of amyloid-β plaques to improve cognition. At this point, we addressed whether SAK3 promotes the degradation of misfolded α-Syn and the aggregates in α-Syn preformed fibril (PFF)-injected mice. The mice were injected with α-Syn PFF in the dorsal striatum, and SAK3 (0.5 or 1.0 mg/kg) was administered orally for three months, either immediately or during the last month after injection. SAK3 significantly inhibited the accumulation of fibrilized phosphorylated-α-Syn in the substantia nigra. Accordingly, SAK3 significantly recovered mesencephalic dopamine neurons from cell death. Decreased α-Syn accumulation was closely associated with increased proteasome activity. Elevated CaMKII/Rpt-6 signaling possibly mediates the enhanced proteasome activity after SAK3 administration in the cortex and hippocampus. CaMKII/Rpt-6 activation also accounted for improved memory and cognition in α-Syn PFF-injected mice. These findings indicate that CaMKII/Rpt-6-dependent proteasomal activation by SAK3 recovers from α-Syn pathology in LBD.


2021 ◽  
Vol 80 (2) ◽  
pp. 885-893
Author(s):  
Simona Daniele ◽  
Filippo Baldacci ◽  
Rebecca Piccarducci ◽  
Giovanni Palermo ◽  
Linda Giampietri ◽  
...  

Background: Red blood cells (RBCs) contain the majority of α-synuclein (α-syn) in blood, representing an interesting model for studying the peripheral pathological alterations proved in neurodegeneration. Objective: The current study aimed to investigate the diagnostic value of total α-syn, amyloid-β (Aβ1–42), tau, and their heteroaggregates in RBCs of Lewy body dementia (LBD) and Alzheimer’s disease (AD) patients compared to healthy controls (HC). Methods: By the use of enzyme-linked immunosorbent assays, RBCs concentrations of total α-syn, Aβ1–42, tau, and their heteroaggregates (α-syn/Aβ1–42 and α-syn/tau) were measured in 27 individuals with LBD (Parkinson’s disease dementia, n = 17; dementia with Lewy bodies, n = 10), 51 individuals with AD (AD dementia, n = 37; prodromal AD, n = 14), and HC (n = 60). Results: The total α-syn and tau concentrations as well as α-syn/tau heterodimers were significantly lower in the LBD group and the AD group compared with HC, whereas α-syn/Aβ1–42 concentrations were significantly lower in the AD dementia group only. RBC α-syn/tau heterodimers had a higher diagnostic accuracy for differentiating patients with LBD versus HC (AUROC = 0.80). Conclusion: RBC α-syn heteromers may be useful for differentiating between neurodegenerative dementias (LBD and AD) and HC. In particular, RBC α-syn/tau heterodimers have demonstrated good diagnostic accuracy for differentiating LBD from HC. However, they are not consistently different between LBD and AD. Our findings also suggest that α-syn, Aβ1–42, and tau interact in vivo to promote the aggregation and accumulation of each other.


Author(s):  
Rahel Feleke ◽  
Regina H. Reynolds ◽  
Amy M. Smith ◽  
Bension Tilley ◽  
Sarah A. Gagliano Taliun ◽  
...  

AbstractParkinson’s disease (PD), Parkinson’s disease with dementia (PDD) and dementia with Lewy bodies (DLB) are three clinically, genetically and neuropathologically overlapping neurodegenerative diseases collectively known as the Lewy body diseases (LBDs). A variety of molecular mechanisms have been implicated in PD pathogenesis, but the mechanisms underlying PDD and DLB remain largely unknown, a knowledge gap that presents an impediment to the discovery of disease-modifying therapies. Transcriptomic profiling can contribute to addressing this gap, but remains limited in the LBDs. Here, we applied paired bulk-tissue and single-nucleus RNA-sequencing to anterior cingulate cortex samples derived from 28 individuals, including healthy controls, PD, PDD and DLB cases (n = 7 per group), to transcriptomically profile the LBDs. Using this approach, we (i) found transcriptional alterations in multiple cell types across the LBDs; (ii) discovered evidence for widespread dysregulation of RNA splicing, particularly in PDD and DLB; (iii) identified potential splicing factors, with links to other dementia-related neurodegenerative diseases, coordinating this dysregulation; and (iv) identified transcriptomic commonalities and distinctions between the LBDs that inform understanding of the relationships between these three clinical disorders. Together, these findings have important implications for the design of RNA-targeted therapies for these diseases and highlight a potential molecular “window” of therapeutic opportunity between the initial onset of PD and subsequent development of Lewy body dementia.


2021 ◽  
Author(s):  
James E. Galvin ◽  
Stephanie Chrisphonte ◽  
Iris Cohen ◽  
Keri K. Greenfield ◽  
Michael J. Kleiman ◽  
...  

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Grace M. Lloyd ◽  
Jess-Karan S. Dhillon ◽  
Kimberly-Marie M. Gorion ◽  
Cara Riffe ◽  
Susan E. Fromholt ◽  
...  

Abstract Background The misfolding of host-encoded proteins into pathological prion conformations is a defining characteristic of many neurodegenerative disorders, including Alzheimer’s disease, Parkinson’s disease, and Lewy body dementia. A current area of intense study is the way in which the pathological deposition of these proteins might influence each other, as various combinations of co-pathology between prion-capable proteins are associated with exacerbation of disease. A spectrum of pathological, genetic and biochemical evidence provides credence to the notion that amyloid β (Aβ) accumulation can induce and promote α-synuclein pathology, driving neurodegeneration. Methods To assess the interplay between α-synuclein and Aβ on protein aggregation kinetics, we crossed mice expressing human α-synuclein (M20) with APPswe/PS1dE9 transgenic mice (L85) to generate M20/L85 mice. We then injected α-synuclein preformed fibrils (PFFs) unilaterally into the hippocampus of 6-month-old mice, harvesting 2 or 4 months later. Results Immunohistochemical analysis of M20/L85 mice revealed that pre-existing Aβ plaques exacerbate the spread and deposition of induced α-synuclein pathology. This process was associated with increased neuroinflammation. Unexpectedly, the injection of α-synuclein PFFs in L85 mice enhanced the deposition of Aβ; whereas the level of Aβ deposition in M20/L85 bigenic mice, injected with α-synuclein PFFs, did not differ from that of mice injected with PBS. Conclusions These studies reveal novel and unexpected interplays between α-synuclein pathology, Aβ and neuroinflammation in mice that recapitulate the pathology of Alzheimer’s disease and Lewy body dementia.


2011 ◽  
Vol 32 (2) ◽  
pp. 143-149 ◽  
Author(s):  
Friederike Fritze ◽  
Uwe Ehrt ◽  
Tibor Hortobagyi ◽  
Clive Ballard ◽  
Dag Aarsland

Author(s):  
Jagan A. Pillai ◽  
James B. Leverenz

This chapter discusses the Pathogenesis of Lew Body Dementia. The Lewy body dementias (LBDs) are a spectrum of dementing neurodegenerative disorders underpinned by the pathological accumulation of α- synuclein protein in both intraneuronal inclusions, “Lewy bodies, ” and neuronal processes, “Lewy neurites”. The chapter concludes that, as with other forms of cognitive impairment in the aged, the pathophysiology of cognitive impairment in LBD is likely multifactorial. Although it appears that α- synuclein pathology, particularly in the limbic and neocortical regions are linked to cognitive changes, other pathologies such as AD likely also play a role. Emphasizing the complexity, a number of genetic factors have been implicated in the LBDs, some specifically with associations to the synucleinopathies and some with other pathophysiologic processes. This complexity will need to be considered as therapeutic interventions are evaluated for the LBD.


1998 ◽  
Vol 4 (6) ◽  
pp. 360-363 ◽  
Author(s):  
E. Jane Byrne

Dementia with cortical Lewy bodies (LBD) was first described by Okazakiet alin 1961 and is now recognised as a relatively common cause of the dementia syndrome. The true prevalence of LBD is unknown. In post-mortem studies of patients diagnosed as having dementia in life, the mean frequency of Lewy body dementia is 12.5% (Byrne, 1997). Clinically diagnosed LBD (using operational clinical criteria) is found in 10–23% of patients presenting to, or in the care of, psychogeriatric services (Collertonet al, 1996). What is not yet certain is its nosological status; opinion is divided between regarding it as a variety of Alzheimer's disease (the Lewy body variant), a distinct disease (senile dementia of the Lewy body type) or a spectrum disorder related to both Parkinson's disease and to Alzheimer's disease (Byrne, 1992).


2021 ◽  
Vol 15 ◽  
Author(s):  
Noritaka Wakasugi ◽  
Takashi Hanakawa

Alzheimer’s disease (AD) is the leading cause of dementia due to neurodegeneration and is characterized by extracellular senile plaques composed of amyloid β1–42 (Aβ) as well as intracellular neurofibrillary tangles consisting of phosphorylated tau (p-tau). Dementia with Lewy bodies constitutes a continuous spectrum with Parkinson’s disease, collectively termed Lewy body disease (LBD). LBD is characterized by intracellular Lewy bodies containing α-synuclein (α-syn). The core clinical features of AD and LBD spectra are distinct, but the two spectra share common cognitive and behavioral symptoms. The accumulation of pathological proteins, which acquire pathogenicity through conformational changes, has long been investigated on a protein-by-protein basis. However, recent evidence suggests that interactions among these molecules may be critical to pathogenesis. For example, Aβ/tau promotes α-syn pathology, and α-syn modulates p-tau pathology. Furthermore, clinical evidence suggests that these interactions may explain the overlapping pathology between AD and LBD in molecular imaging and post-mortem studies. Additionally, a recent hypothesis points to a common mechanism of prion-like progression of these pathological proteins, via neural circuits, in both AD and LBD. This suggests a need for understanding connectomics and their alterations in AD and LBD from both pathological and functional perspectives. In AD, reduced connectivity in the default mode network is considered a hallmark of the disease. In LBD, previous studies have emphasized abnormalities in the basal ganglia and sensorimotor networks; however, these account for movement disorders only. Knowledge about network abnormalities common to AD and LBD is scarce because few previous neuroimaging studies investigated AD and LBD as a comprehensive cohort. In this paper, we review research on the distribution and interactions of pathological proteins in the brain in AD and LBD, after briefly summarizing their clinical and neuropsychological manifestations. We also describe the brain functional and connectivity changes following abnormal protein accumulation in AD and LBD. Finally, we argue for the necessity of neuroimaging studies that examine AD and LBD cases as a continuous spectrum especially from the proteinopathy and neurocircuitopathy viewpoints. The findings from such a unified AD and Parkinson’s disease (PD) cohort study should provide a new comprehensive perspective and key data for guiding disease modification therapies targeting the pathological proteins in AD and LBD.


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