Abstract
Alzheimer’s disease (AD) is a neurodegenerative disorder. The pathohistological features in AD are intracellular accumulation of neurofibrillary tangles and extracellular senile plaques. Plaque deposition leads to recruitment and activation of microglial cells, which induces neuroinflammation and drives neurodegeneration. Recent evidence show that soluble pre-fibrillar Aβ species, rather than insoluble fibrils, are highly neurotoxic and correlate with disease severity.Hence, preventing formation of soluble Aβ and its interaction with neurons is a major goal in AD. Despite massive efforts, how extracellular factors regulate assembly of Aβ peptide and neurotoxic activity of Aβ species is still largely undefined. Recent studies indicate that Extracellular Vesicles (EVs), including exosomes and PM-derived microvesicles (MVs), may influence Aβ neurotoxicity. Our findings reveal that production of microglial MVs (m-MVs) is strikingly high in patients with mild cognitive impairment and AD as compared to healthy controls and positively correlates with markers of neurodegeneration and hippocampal atrophy. Furthermore we found that MVs isolated from the CSF of AD patients are toxic to cultured hippocampal neurons. Through in vitro studies we demonstrate that the m-MVs promote generation of neurotoxic soluble species from almost inert Aβ aggregates, which is mediated by lipid components of MVs. Our findings suggest that m-MVs favor formation of neurotoxic Aβ species throughout the brain, possibly representing the mechanism behind transynaptic spread of Aβ in AD. On the other hand, studies conducted by Yuyama et al 2012, 2014 & An et al 2013 suggest that exosomes produced by neurons may exert opposite action by neutralizing neurotoxicity of soluble Aβ. To verify if the overall effect of exosomes and MVs on Aβ neurotoxicity may vary depending on parental cell type we are currently studying the influence of EVs (exosomes & MVs) derived from distinct brain cells on Aβ toxicity and assembly.
Highlights
Alzheimer’s disease (AD) is an incurable neurodegenerative disease characterized by progressive dementia
The results of the present study indicate that development of the neuronal hypoxic tolerance induced by the three-trial, in contrast to one-trial, mild hypoxic preconditioning is apparently largely associated with the activation of CREB, as well as brain-derived neurotrophic factor (BDNF) and Bcl-2 overexpression
No significant differences in serum level of Solubile form of RAGE (sRAGE) where found between rapidly progressing and slow progressing subgroup of multiple sclerosis (MS) patients.Our results suggest for the role of sRAGE in MS ethiopathogenesis, but we did not find any association of sRAGE in serum with the rate of MS disability progression
Summary
Alzheimer’s disease (AD) is an incurable neurodegenerative disease characterized by progressive dementia. The aim of the study was to characterize the effects of streptozocin (STZ)-indced diabetes on learning and memory of 5XFAD and wild-type (WT) mice in Morris water maze (MWM) at ages 2 and 6 months and on brain amyloid load. Existing evidence suggests GABAergic system is involved in pathophysiology of Alzheimer’s disease (AD) via inhibitory interneuron deficits (Verret et al, 2012) and decrease in functional GABAA receptors (Limon et al, 2012). Our concept: low doses of muscimol may prevent learning/memory deficits in intracerebroventricular (icv) streptozocin (STZ)-induced AD nontransgenic rat model. The Sigma-1 receptor is a chaperone protein that modulates intracellular calcium signalling of the endoplasmatic reticulum and is involved in learning and memory processes.The aim of the present study was to compare in vitro Ca2+ concentration modulating activity and in vivo behavioural effects of enantiomers of methylphenylpiracetam, a novel positive allosteric modulator of Sigma-1 receptors
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