Mitochondrially-Targeted Therapeutic Strategies for Alzheimer's Disease

2021 ◽  
Vol 18 ◽  
Author(s):  
Isaac G. Onyango ◽  
James P. Bennett ◽  
Gorazd B. Stokin
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Epigenetic Modification ◽  
Disease Process ◽  
Amyloid Β ◽  
Lifestyle Changes ◽  
Mtdna Mutations ◽  
The Central Nervous System ◽  
Repurposed Drugs ◽  
Altered Gene

: Alzheimer's disease (AD) is an irreversible, progressive neurodegenerative disease and the most common cause of dementia among older adults. There are no effective treatments avail- able for the disease, and it is associated with great societal concern because of the substantial costs of providing care to its sufferers, whose numbers will increase as populations age. While multiple causes have been proposed to be significant contributors to the onset of sporadic AD, increased age is a unifying risk factor. In addition to amyloid-β (Aβ) and tau protein playing a key role in the initi- ation and progression of AD, impaired mitochondrial bioenergetics and dynamics are likely major etiological factors in AD pathogenesis and have many potential origins, including Aβ and tau. Mito- chondrial dysfunction is evident in the central nervous system (CNS) and systemically early in the disease process. Addressing these multiple mitochondrial deficiencies is a major challenge of mito- chondrial systems biology. We review evidence for mitochondrial impairments ranging from mito- chondrial DNA (mtDNA) mutations to epigenetic modification of mtDNA, altered gene expres- sion, impaired mitobiogenesis, oxidative stress, altered protein turnover and changed organelle dy- namics (fission and fusion). We also discuss therapeutic approaches, including repurposed drugs, epigenetic modifiers, and lifestyle changes that target each level of deficiency which could poten- tially alter the course of this progressive, heterogeneous Disease while being cognizant that success- ful future therapeutics may require a combinatorial approach.

Prions and Neurodegenerative Diseases: A Focus on Alzheimer’s Disease

2021 ◽  
pp. 1-16
Author(s):  
Alessio Crestini ◽  
Francesca Santilli ◽  
Stefano Martellucci ◽  
Elena Carbone ◽  
Maurizio Sorice ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Diseases ◽  
Protein Misfolding ◽  
Amyloid Β ◽  
Specific Protein ◽  
Cellular Prion Protein ◽  
Aβ Oligomers ◽  
The Central Nervous System ◽  
Induced Signal

Specific protein misfolding and aggregation are mechanisms underlying various neurodegenerative diseases such as prion disease and Alzheimer’s disease (AD). The misfolded proteins are involved in prions, amyloid-β (Aβ), tau, and α-synuclein disorders; they share common structural, biological, and biochemical characteristics, as well as similar mechanisms of aggregation and self-propagation. Pathological features of AD include the appearance of plaques consisting of deposition of protein Aβ and neurofibrillary tangles formed by the hyperphosphorylated tau protein. Although it is not clear how protein aggregation leads to AD, we are learning that the cellular prion protein (PrPC) plays an important role in the pathogenesis of AD. Herein, we first examined the pathogenesis of prion and AD with a focus on the contribution of PrPC to the development of AD. We analyzed the mechanisms that lead to the formation of a high affinity bond between Aβ oligomers (AβOs) and PrPC. Also, we studied the role of PrPC as an AβO receptor that initiates an AβO-induced signal cascade involving mGluR5, Fyn, Pyk2, and eEF2K linking Aβ and tau pathologies, resulting in the death of neurons in the central nervous system. Finally, we have described how the PrPC-AβOs interaction can be used as a new potential therapeutic target for the treatment of PrPC-dependent AD.

scholarly journals Alzheimer’s disease: many failed trials, so where do we go from here?

2020 ◽  
Vol 68 (6) ◽  
pp. 1135-1140 ◽  
Author(s):  
Allison Bethanne Reiss ◽  
Amy D Glass ◽  
Thomas Wisniewski ◽  
Benjamin Wolozin ◽  
Irving H Gomolin ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Current Knowledge ◽  
Memory Loss ◽  
Treatment Strategies ◽  
Amyloid Β ◽  
Tau Proteins ◽  
Brain Disorder ◽  
The Central Nervous System ◽  
Progressive Cognitive Impairment

Alzheimer’s disease (AD) is a neurodegenerative brain disorder associated with relentlessly progressive cognitive impairment and memory loss. AD pathology proceeds for decades before cognitive deficits become clinically apparent, opening a window for preventative therapy. Imbalance of clearance and buildup of amyloid β and phosphorylated tau proteins in the central nervous system is believed to contribute to AD pathogenesis. However, multiple clinical trials of treatments aimed at averting accumulation of these proteins have yielded little success, and there is still no disease-modifying intervention. Here, we discuss current knowledge of AD pathology and treatment with an emphasis on emerging biomarkers and treatment strategies.

scholarly journals Microglia, TREM2, and Therapeutic Methods of Alzheimer’s Disease

2021 ◽  
Author(s):  
Siwei Xu ◽  
Yaya Ji ◽  
Tianle Sha ◽  
Haoming Li
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Dynamic Change ◽  
Amyloid Β ◽  
Neuronal Loss ◽  
Pathological Process ◽  
Amyloid Β Protein ◽  
Transmembrane Glycoprotein ◽  
Β Protein ◽  
The Central Nervous System

Alzheimer’s disease (AD) is one of the most common causes of dementia all around the world. It is characterized by the deposition of amyloid-β protein (Aβ) and the formation of neurofibrillary tangles (NFTs), which contribute to neuronal loss and cognitive decline. Microglia, as innate immune cells in brain, plays dual roles in the pathological process of AD. Expression in different subtypes of microglia is diverse in AD genes. Triggering receptor expressed on myeloid cells 2 (TREM2) is a transmembrane glycoprotein mainly expressed on microglia in the central nervous system (CNS). Soluble TREM2 (sTREM2), a proteolytic product of TREM2, which is abundant in the cerebrospinal fluid, shows a dynamic change in different stages and ameliorates the pathological process of AD. The interplay between the different subtypes of apolipoprotein and TREM2 is closely related to the mechanism of AD and serves as important regulatory sites. Moreover, several therapeutic strategies targeting TREM2 have shown positive outcomes during clinical trials and some novel therapies at different points are in progress. In this review, we mainly talk about the interrelationships among microglia, TREM2, and AD, and hope to give an overview of the strategies of AD.

scholarly journals Phosphorylation Signaling in APP Processing in Alzheimer’s Disease

2019 ◽  
Vol 21 (1) ◽  
pp. 209 ◽  
Author(s):  
Tao Zhang ◽  
Dongmei Chen ◽  
Tae Ho Lee
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Signaling Pathways ◽  
Physiological Function ◽  
Amyloid Β ◽  
Proteolytic Processing ◽  
App Processing ◽  
Abnormal Accumulation ◽  
The Central Nervous System ◽  
The Brain

The abnormal accumulation of amyloid-β (Aβ) in the central nervous system is a hallmark of Alzheimer’s disease (AD). The regulation of the processing of the single- transmembrane amyloid precursor protein (APP) plays an important role in the generation of Aβ in the brain. The phosphorylation of APP and key enzymes involved in the proteolytic processing of APP has been demonstrated to be critical for modulating the generation of Aβ by either altering the subcellular localization of APP or changing the enzymatic activities of the secretases responsible for APP processing. In addition, the phosphorylation may also have an impact on the physiological function of these proteins. In this review, we summarize the kinases and signaling pathways that may participate in regulating the phosphorylation of APP and secretases and how this further affects the function and processing of APP and Aβ pathology. We also discuss the potential of approaches that modulate these phosphorylation-signaling pathways or kinases as interventions for AD pathology.

Phosphorylation and Glycosylation of Amyloid-β Protein Precursor: The Relationship to Trafficking and Cleavage in Alzheimer’s Disease

2021 ◽  
pp. 1-21
Author(s):  
Xi-Jun Song ◽  
He-Yan Zhou ◽  
Yu-Ying Sun ◽  
Han-Chang Huang
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurodegenerative Disorder ◽  
Senile Plaques ◽  
Amyloid Β ◽  
Amyloid Β Protein ◽  
Protein Precursor ◽  
Β Protein ◽  
Cleavage Enzyme ◽  
The Central Nervous System

Alzheimer’s disease (AD) is a neurodegenerative disorder in the central nervous system, and this disease is characterized by extracellular senile plaques and intracellular neurofibrillary tangles. Amyloid-β (Aβ) peptide is the main constituent of senile plaques, and this peptide is derived from the amyloid-β protein precursor (AβPP) through the successive cleaving by β-site AβPP-cleavage enzyme 1 (BACE1) and γ-secretase. AβPP undergoes the progress of post-translational modifications, such as phosphorylation and glycosylation, which might affect the trafficking and the cleavage of AβPP. In the recent years, about 10 phosphorylation sites of AβPP were identified, and they play complex roles in glycosylation modification and cleavage of AβPP. In this article, we introduced the transport and the cleavage pathways of AβPP, then summarized the phosphorylation and glycosylation sites of AβPP, and further discussed the links and relationship between phosphorylation and glycosylation on the pathways of AβPP trafficking and cleavage in order to provide theoretical basis for AD research.

scholarly journals Immunotherapeutic Strategies for Alzheimer's Disease Treatment

2009 ◽  
Vol 9 ◽  
pp. 909-919 ◽  
Author(s):  
Beka Solomon
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Passive Immunization ◽  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Disease Treatment ◽  
Naturally Occurring ◽  
Age Related ◽  
The Central Nervous System ◽  
Naturally Occurring Antibodies

Naturally occurring antibodies against amyloid-β peptides have been found in human cerebrospinal fluid and in the plasma of healthy individuals, but were significantly lower in Alzheimer's disease (AD) patients, suggesting that AD may be an immunodeficient disorder. The performance of anti-amyloid-β antibodies in transgenic mice models of AD showed that they are delivered to the central nervous system, preventing and dissolving amyloid-β plaques. Moreover, these antibodies protected the mice from learning and age-related memory deficits. Active and/or passive immunization against the amyloid-β peptide has been proposed as a method for preventing and/or treating AD. Immunotherapy represents fascinating ways to test the amyloid hypothesis and offers genuine opportunities for AD treatment, but requires careful antigen and antibody selection to maximize efficacy and minimize adverse events.

scholarly journals Relationship between cortical iron and tau aggregation in Alzheimer’s disease

Brain ◽  
2020 ◽  
Vol 143 (5) ◽  
pp. 1341-1349 ◽  
Author(s):  
Nicola Spotorno ◽  
Julio Acosta-Cabronero ◽  
Erik Stomrud ◽  
Björn Lampinen ◽  
Olof T Strandberg ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Critical Role ◽  
Disease Process ◽  
Amyloid Β ◽  
Cortical Atrophy ◽  
Tau Pet ◽  
Tau Aggregation ◽  
The Relationship

Abstract A growing body of evidence suggests that the dysregulation of neuronal iron may play a critical role in Alzheimer’s disease. Recent MRI studies have established a relationship between iron accumulation and amyloid-β aggregation. The present study provides further insight demonstrating a relationship between iron and tau accumulation using magnetic resonance-based quantitative susceptibility mapping and tau-PET in n = 236 subjects with amyloid-β pathology (from the Swedish BioFINDER-2 study). Both voxel-wise and regional analyses showed a consistent association between differences in bulk magnetic susceptibility, which can be primarily ascribed to an increase in iron content, and tau-PET signal in regions known to be affected in Alzheimer’s disease. Subsequent analyses revealed that quantitative susceptibility specifically mediates the relationship between tau-PET and cortical atrophy measures, thus suggesting a modulatory effect of iron burden on the disease process. We also found evidence suggesting the relationship between quantitative susceptibility and tau-PET is stronger in younger participants (age ≤ 65). Together, these results provide in vivo evidence of an association between iron deposition and both tau aggregation and neurodegeneration, which help advance our understanding of the role of iron dysregulation in the Alzheimer’s disease aetiology.

scholarly journals Glymphatic system, AQP4, and their implications in Alzheimer’s disease

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Inês Silva ◽  
Jéssica Silva ◽  
Rita Ferreira ◽  
Diogo Trigo
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Central Nervous System ◽  
Nervous System ◽  
Lymphatic System ◽  
Amyloid Β ◽  
Glymphatic System ◽  
Associated Proteins ◽  
The Central Nervous System ◽  
Controversial Topic

AbstractLacking conventional lymphatic system, the central nervous system requires alternative clearance systems, such as the glymphatic system, which promotes clearance of interstitial solutes. Aquaporin-4 water channels (AQP4) are an integral part of this system and related to neuropathologies, such as Alzheimer’s disease (AD). The clearance of Alzheimer’s associated proteins amyloid β and tau is diminished by glymphatic system impairment, due to lack of AQP4. Even though AQP4 mislocalisation (which affects its activity) is a phenotype of AD, it remains a controversial topic, as it is still unclear if it is a phenotype-promoting factor or a consequence of this pathology. This review provides important and updated knowledge about glymphatic system, AQP4 itself, and their link with Alzheimer’s disease. Finally, AQP4 as a therapeutic target is proposed to ameliorate Alzheimer’s Disease and other neuropathologies AQP4-related.

scholarly journals Distinct microglial response against Alzheimer's amyloid and tau pathologies characterized by P2Y12 receptor

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Jun Maeda ◽  
Takeharu Minamihisamatsu ◽  
Masafumi Shimojo ◽  
Xiaoyun Zhou ◽  
Maiko Ono ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Early Stage ◽  
Receptor Gene ◽  
Amyloid Β ◽  
Progressive Increase ◽  
P2y12 Receptor ◽  
Down Regulation ◽  
Disease Etiology ◽  
The Central Nervous System

Abstract Microglia are the resident phagocytes of the central nervous system, and microglial activation is considered to play an important role in the pathogenesis of neurodegenerative diseases. Recent studies with single-cell RNA analysis of CNS cells in Alzheimer’s disease and diverse other neurodegenerative conditions revealed that the transition from homeostatic microglia to disease-associated microglia was defined by changes of gene expression levels, including down-regulation of the P2Y12 receptor gene (P2Y12R). However, it is yet to be clarified in Alzheimer’s disease brains whether and when this down-regulation occurs in response to amyloid-β and tau depositions, which are core pathological processes in the disease etiology. To further evaluate the significance of P2Y12 receptor alterations in the neurodegenerative pathway of Alzheimer’s disease and allied disorders, we generated an anti-P2Y12 receptor antibody and examined P2Y12 receptor expressions in the brains of humans and model mice bearing amyloid-β and tau pathologies. We observed that the brains of both Alzheimer’s disease and non-Alzheimer’s disease tauopathy patients and tauopathy model mice (rTg4510 and PS19 mouse lines) displayed declined microglial P2Y12 receptor levels in regions enriched with tau inclusions, despite an increase in the total microglial population. Notably, diminution of microglial immunoreactivity with P2Y12 receptor was noticeable prior to massive accumulations of phosphorylated tau aggregates and neurodegeneration in rTg4510 mouse brains, despite a progressive increase of total microglial population. On the other hand, Iba1-positive microglia encompassing compact and dense-cored amyloid-β plaques expressed P2Y12 receptor at varying levels in amyloid precursor protein (APP) mouse models (APP23 and AppNL-F/NL-F mice). By contrast, neuritic plaques in Alzheimer’s disease brains were associated with P2Y12 receptor-negative microglia. These data suggest that the down-regulation of microglia P2Y12 receptor, which is characteristic of disease-associated microglia, is intimately associated with tau rather than amyloid-β pathologies from an early stage and could be a sensitive index for neuroinflammatory responses to Alzheimer’s disease-related neurodegenerative processes.

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