scholarly journals Lysosomal Fusion Dysfunction as a Unifying Hypothesis for Alzheimer's Disease Pathology

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Kristen E. Funk ◽  
Jeff Kuret

Alzheimer's disease is characterized pathologically by extracellular senile plaques, intracellular neurofibrillary tangles, and granulovacuolar degeneration. It has been debated whether these hallmark lesions are markers or mediators of disease progression, and numerous paradigms have been proposed to explain the appearance of each lesion individually. However, the unfaltering predictability of these lesions suggests a single pathological nidus central to disease onset and progression. One of the earliest pathologies observed in Alzheimer's disease is endocytic dysfunction. Here we review the recent literature of endocytic dysfunction with particular focus on disrupted lysosomal fusion and propose it as a unifying hypothesis for the three most-studied lesions of Alzheimer's disease.

1997 ◽  
Vol 352 (1363) ◽  
pp. 1781-1792 ◽  
Author(s):  
Brian H. Anderton

The brains of individuals, who are cognitively normal, show age–related changes that include an overall reduction in brain volume and weight, which are associated with gyral atrophy and widening of the sulci of the cerebral cortex, and enlargement of the brain ventricles. These changes are partly the result of nerve cell loss but accurate estimates of neuronal loss are notoriously difficult to make. Microscopically, there are increasing amounts of the age–related pigment, lipofuscin, granulovacuolar degeneration in neurons, Hirano bodies, variable amounts of diffuse deposits of β–amyloid in the parenchyma, the presence of neurofibrillary tangles mainly confined to the hippocampus and amygdala, and sparse numbers of senile plaques in these brain regions and also in other cortical areas. Of these changes, neurofibrillary tangles and senile plaques are the neuropathological hallmark of Alzheimer's disease in which they are more abundant and widespread. Alzheimer's disease has therefore been regarded as accelerated brain ageing; however, the realization that there is a strong genetic contribution to developing the disease at least implies that it may not be the inevitable, even if frequent, consequence of old age. Understanding the molecular basis of plaque and tangle formation is advancing greatly and is the main focus of research into the cellular and molecular changes observed in the ageing brain.


2021 ◽  
pp. 1-22
Author(s):  
Mariana Van Zeller ◽  
Diogo M. Dias ◽  
Ana M. Sebastião ◽  
Cláudia A. Valente

Alzheimer’s disease (AD) is the most prevalent neurodegenerative disease commonly diagnosed among the elderly population. AD is characterized by the loss of synaptic connections, neuronal death, and progressive cognitive impairment, attributed to the extracellular accumulation of senile plaques, composed by insoluble aggregates of amyloid-β (Aβ) peptides, and to the intraneuronal formation of neurofibrillary tangles shaped by hyperphosphorylated filaments of the microtubule-associated protein tau. However, evidence showed that chronic inflammatory responses, with long-lasting exacerbated release of proinflammatory cytokines by reactive glial cells, contribute to the pathophysiology of the disease. NLRP3 inflammasome (NLRP3), a cytosolic multiprotein complex sensor of a wide range of stimuli, was implicated in multiple neurological diseases, including AD. Herein, we review the most recent findings regarding the involvement of NLRP3 in the pathogenesis of AD. We address the mechanisms of NLRP3 priming and activation in glial cells by Aβ species and the potential role of neurofibrillary tangles and extracellular vesicles in disease progression. Neuronal death by NLRP3-mediated pyroptosis, driven by the interneuronal tau propagation, is also discussed. We present considerable evidence to claim that NLRP3 inhibition, is undoubtfully a potential therapeutic strategy for AD.


2019 ◽  
Vol 20 (7) ◽  
pp. 1664 ◽  
Author(s):  
Anita Gołaszewska ◽  
Wojciech Bik ◽  
Tomasz Motyl ◽  
Arkadiusz Orzechowski

The average life span steadily grows in humans and in animals kept as pets or left in sanctuaries making the issue of elderly-associated cognitive impairment a hot-spot for scientists. Alzheimer’s disease (AD) is the most prevalent cause of progressive mental deterioration in aging humans, and there is a growing body of evidence that similar disorders (Alzheimer’s-like diseases, ALD) are observed in animals, more than ever found in senescent individuals. This review reveals up to date knowledge in pathogenesis, hallmarks, diagnostic approaches and modalities in AD faced up with ALD related to different animal species. If found at necropsy, there are striking similarities between senile plaques (SP) and neurofibrillary tangles (NFT) in human and animal brains. Also, the set of clinical symptoms in ALD resembles that observed in AD. At molecular and microscopic levels, the human and animal brain histopathology in AD and ALD shows a great resemblance. AD is fatal, and the etiology is still unknown, although the myriad of efforts and techniques were employed in order to decipher the molecular mechanisms of disease onset and its progression. Nowadays, according to an increasing number of cases reported in animals, apparently, biochemistry of AD and ALD has a lot in common. Described observations point to the importance of extensive in vivo models and extensive pre-clinical studies on aging animals as a suitable model for AD disease.


1993 ◽  
Vol 49 (1) ◽  
pp. 41-62 ◽  
Author(s):  
Manuel F. Casanova ◽  
Nicholas W. Carosella ◽  
James M. Gold ◽  
Joel E. Kleinman ◽  
Daniel R. Weinberger ◽  
...  

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Troy T. Rohn

Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by a progressive loss of memory and cognitive skills. Although much attention has been devoted concerning the contribution of the microscopic lesions, senile plaques, and neurofibrillary tangles to the disease process, inflammation has long been suspected to play a major role in the etiology of AD. Recently, a novel variant in the gene encoding the triggering receptor expressed on myeloid cells 2 (TREM2) has been identified that has refocused the spotlight back onto inflammation as a major contributing factor in AD. Variants in TREM2 triple one's risk of developing late-onset AD. TREM2 is expressed on microglial cells, the resident macrophages in the CNS, and functions to stimulate phagocytosis on one hand and to suppress cytokine production and inflammation on the other hand. The purpose of this paper is to discuss these recent developments including the potential role that TREM2 normally plays and how loss of function may contribute to AD pathogenesis by enhancing oxidative stress and inflammation within the CNS. In this context, an overview of the pathways linking beta-amyloid, neurofibrillary tangles (NFTs), oxidative stress, and inflammation will be discussed.


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