scholarly journals Melanoma-secreted Amyloid Beta Suppresses Neuroinflammation and Promotes Brain Metastasis

2019 ◽  
Author(s):  
Kevin Kleffman ◽  
Grace Levinson ◽  
Eitan Wong ◽  
Francisco Galán-Echevarría ◽  
Richard Von-Itter ◽  
...  

SummaryBrain metastasis is a significant cause of morbidity and mortality in multiple cancer types and represents an unmet clinical need. The mechanisms that mediate metastatic cancer growth in the brain parenchyma are largely unknown. Melanoma, which has the highest rate of brain metastasis among common cancer types, is an ideal model to study how cancer cells adapt to the brain parenchyma. We performed unbiased proteomics analysis of melanoma short-term cultures, a novel model for the study of brain metastasis. Intriguingly, we found that proteins implicated in neurodegenerative pathologies are differentially expressed in melanoma cells explanted from brain metastases compared to those derived from extracranial metastases. This raised the exciting hypothesis that molecular pathways implicated in neurodegenerative disorders are critical for metastatic adaptation to the brain.Here, we show that melanoma cells require amyloid beta (Aβ), a polypeptide heavily implicated in Alzheimer’s disease, for growth and survival in the brain parenchyma. Melanoma cells produce and secrete Aβ, which activates surrounding astrocytes to a pro-metastatic, anti-inflammatory phenotype. Furthermore, we show that pharmacological inhibition of Aβ decreases brain metastatic burden.Our results reveal a mechanistic connection between brain metastasis and Alzheimer’s disease – two previously unrelated pathologies, establish Aβ as a promising therapeutic target for brain metastasis, and demonstrate suppression of neuroinflammation as a critical feature of metastatic adaptation to the brain parenchyma.

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 957
Author(s):  
Brad T. Casali ◽  
Erin G. Reed-Geaghan

Microglia are the resident immune cells of the brain, deriving from yolk sac progenitors that populate the brain parenchyma during development. During development and homeostasis, microglia play critical roles in synaptogenesis and synaptic plasticity, in addition to their primary role as immune sentinels. In aging and neurodegenerative diseases generally, and Alzheimer’s disease (AD) specifically, microglial function is altered in ways that significantly diverge from their homeostatic state, inducing a more detrimental inflammatory environment. In this review, we discuss the receptors, signaling, regulation and gene expression patterns of microglia that mediate their phenotype and function contributing to the inflammatory milieu of the AD brain, as well as strategies that target microglia to ameliorate the onset, progression and symptoms of AD.


2008 ◽  
Vol 29 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Li Gan ◽  
Shuhong Qiao ◽  
Xun Lan ◽  
Liying Chi ◽  
Chun Luo ◽  
...  

Nanoscale ◽  
2017 ◽  
Vol 9 (30) ◽  
pp. 10619-10632 ◽  
Author(s):  
Faiz Ul Amin ◽  
Ali Kafash Hoshiar ◽  
Ton Duc Do ◽  
Yeongil Noh ◽  
Shahid Ali Shah ◽  
...  

Alzheimer's disease (AD) is the most prevalent age-related neurodegenerative disease, pathologically characterized by the accumulation of aggregated amyloid beta (Aβ) in the brain.


US Neurology ◽  
2018 ◽  
Vol 14 (1) ◽  
pp. 15 ◽  
Author(s):  
Nenad Bogdanovic

Current neuropathologic examination of the brain is still the gold standard for diagnosis of Alzheimer’s disease (AD). Postmortem studies, however, have indicated that current methods for the clinical diagnosis of AD are suboptimal.1Recent research has demonstrated the clinical utility of amyloid-beta positron emission tomography (PET) scans, which detect the presence of amyloid-beta plaques in the brain. In a study presented at the Alzheimer’s Association International Conference (AAIC) in London, UK, July 2017, by Nenad Bogdanovic, MD, PhD, of the University of Oslo in Norway, amyloid PET imaging was found to be a fundamental diagnostic tool for AD, establishing a definite diagnosis or excluding AD in all 50 study participants.2 The use of cerebrospinal fluid (CSF) amyloid testing with a higher amyloid-beta plaque threshold than that traditionally used to establish a positive finding also resulted in high diagnostic accuracy, resulting in diagnosis or exclusion in 44 of 50 participants (88%) compared with only 21 individuals (42%) using traditional cutoffs.2


2019 ◽  
Vol 40 (11) ◽  
pp. 2179-2187 ◽  
Author(s):  
Cristian Salinas ◽  
Talakad G Lohith ◽  
Ajay Purohit ◽  
Arie Struyk ◽  
Cyrille Sur ◽  
...  

[18F]MK-6240 is a selective, high-affinity PET radiotracer for imaging neurofibrillary tangles (NFT) in Alzheimer’s disease (AD). Herein, we report test–retest (T–RT) reproducibility of [18F]MK-6240 in AD and healthy volunteers (HV). Twelve subjects with AD and three cognitively normal HV were enrolled in the study and dynamically scanned for 150 min with [18F]MK-6240 under a T–RT protocol. Two radioactivity doses were investigated: 165 ± 3 MBq (n = 6) and 300 ± 40 MBq (n = 9). Serial arterial blood samples were taken for each scan to obtain metabolite-corrected input functions. Following intravenous administration of [18F]MK-6240, the tracer rapidly partitioned into the brain and its heterogenous distribution pattern was consistent with known NFT pathology in AD. In contrast, uptake in HV was low and uniform across the brain parenchyma. Across all subjects, average T–RT variabilities in NFT-rich regions were ∼21%, ∼14% and ∼6% for various quantitative metrics: total distribution volume (VT), binding potential (BPND), and standardized uptake ratio (SUVR90–120), respectively. No significant differences in SUVR T–RT variability were observed between the high and low injected radioactivity groups (5.6% and 6.1%, respectively). This work suggests [18F]MK-6240 has adequate SUVR T–RT characteristics supporting the use of this outcome in future studies.


Author(s):  
Angélica María Sabogal-Guáqueta ◽  
Julián David Arias-Londoño ◽  
Johanna Gutierrez-Vargas ◽  
D. Sepulveda-Falla ◽  
M. Glatzel ◽  
...  

2001 ◽  
Vol 67 ◽  
pp. 1-14 ◽  
Author(s):  
David Allsop ◽  
Lance J. Twyman ◽  
Yvonne Davies ◽  
Susan Moore ◽  
Amber York ◽  
...  

Alzheimer's disease (AD) is the most common cause of dementia in old age and presently affects an estimated 4 million people in the U.S.A. and 0.75 million people in the U.K. It is a relentless, degenerative brain disease, characterized by progressive cognitive impairment. In the final stages of the disease, patients are often bedridden, doubly incontinent and unable to speak or to recognize close relatives. Pathological changes of Alzheimer's disease include extensive neuronal loss and the presence of numerous neurofibrillary tangles and senile plaques in the brain. The senile plaques contain amyloid fibrils derived from a 39-43-amino-acid peptide referred to as ϐ-amyloid or Aϐ. The basic theory of the so-called 'amyloid hypothesis' is that the deposition of aggregated forms of Aϐ in the brain parenchyma triggers a pathological cascade of events that leads to neurofibrillary tangle formation, neuronal loss and the associated dementia [1]. Here we discuss progress towards the identification of inhibitors of Aϐ production and fibrillization.


2020 ◽  
Vol 26 (12) ◽  
pp. 1345-1355 ◽  
Author(s):  
Spencer Servizi ◽  
Rachel R. Corrigan ◽  
Gemma Casadesus

Type II Diabetes (T2D) is a major risk factor for Alzheimer’s Disease (AD). These two diseases share several pathological features, including amyloid accumulation, inflammation, oxidative stress, cell death and cognitive decline. The metabolic hormone amylin and amyloid-beta are both amyloids known to self-aggregate in T2D and AD, respectively, and are thought to be the main pathogenic entities in their respective diseases. Furthermore, studies suggest amylin’s ability to seed amyloid-beta aggregation, the activation of common signaling cascades in the pancreas and the brain, and the ability of amyloid beta to signal through amylin receptors (AMYR), at least in vitro. However, paradoxically, non-aggregating forms of amylin such as pramlintide are given to treat T2D and functional and neuroprotective benefits of amylin and pramlintide administration have been reported in AD transgenic mice. These paradoxical results beget a deeper study of the complex nature of amylin’s signaling through the several AMYR subtypes and other receptors associated with amylin effects to be able to fully understand its potential role in mediating AD development and/or prevention. The goal of this review is to provide such critical insight to begin to elucidate how the complex nature of this hormone’s signaling may explain its equally complex relationship with T2D and mechanisms of AD pathogenesis.


Author(s):  
Y.-Q. Zeng ◽  
Y.-J. Wang ◽  
X.-F. Zhou

The extracellular accumulation of amyloid beta protein (Aβ), reactive gliosis and cerebral amyloid angiopathy (CAA) play critical roles in the pathogenesis of Alzheimer’s disease (AD). Ginkgetin, a biflavone isolated from Ginkgo biloba leaves, was previously reported to exhibit strong neuroprotection against cytotoxic insults induced by oxidative stress and amyloid beta, but it remains unclear whether ginkgetin has therapeutic effect on Alzheimer’s disease (AD) in vivo. In the present study, we investigated 9 months treatment effects of ginkgetin diet in APP/PS1 mice. Our results show that ginkgetin can significantly reduce plasma Aβ levels 59% and Aβ plaque 51% in the brain of APP/PS1 transgenic mice (P<0.05), effectively inhibits cerebral microhemorrhage 69% (P<0.05), significantly decreases astrogliosis 50% and ameliorate inflammation (P<0.05), exhibits several biological properties for AD.


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