scholarly journals A High Fat/Cholesterol Diet Recapitulates Some Alzheimer’s Disease-Like Features in Mice: Focus on Hippocampal Mitochondrial Dysfunction

2021 ◽  
pp. 1-15
Author(s):  
Gianni Mancini ◽  
Candida Dias ◽  
Catia F. Lourenço ◽  
Joao Laranjinha ◽  
Andreza de Bem ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Risk Factor ◽  
Mitochondrial Dysfunction ◽  
Cognitive Performance ◽  
Mitochondrial Function ◽  
No Production ◽  
Cholesterol Diet ◽  
High Fat ◽  
Ample Evidence

Background: Ample evidence from clinical and pre-clinical studies suggests mid-life hypercholesterolemia as a risk factor for developing Alzheimer’s disease (AD) at a later age. Hypercholesterolemia induced by dietary habits can lead to vascular perturbations that increase the risk of developing sporadic AD. Objective: To investigate the effects of a high fat/cholesterol diet (HFCD) as a risk factor for AD by using a rodent model of AD and its correspondent control (healthy animals). Methods: We compared the effect of a HFCD in normal mice (non-transgenic mice, NTg) and the triple transgenic mouse model of AD (3xTgAD). We evaluated cognitive performance in relation to changes in oxidative metabolism and neuron-derived nitric oxide (•NO) concentration dynamics in hippocampal slices as well as histochemical staining of markers of the neurovascular unit. Results: In NTg, the HFCD produced only moderate hypercholesterolemia but significant decline in spatial memory was observed. A tendency for decrease in •NO production was accompanied by compromised mitochondrial function with decrease in spare respiratory capacity. In 3xTgAD mice, a robust increase in plasma cholesterol levels with the HFCD did not worsen cognitive performance but did induce compromise of mitochondrial function and significantly decreased •NO production. We found increased staining of biomarkers for astrocyte endfeet and endothelial cells in 3xTgAD hippocampi, which was further increased by the HFCD. Conclusion: A short term (8 weeks) intervention with HFCD can produce an AD-like phenotype even in the absence of overt systemic hypercholesterolemia and highlight mitochondrial dysfunction as a link between hypercholesterolemia and sporadic AD.

scholarly journals Mitochondrial Dysfunction and Oxidative Stress in Alzheimer’s Disease

2021 ◽  
Vol 13 ◽  
Author(s):  
Afzal Misrani ◽  
Sidra Tabassum ◽  
Li Yang
Keyword(s):  
Oxidative Stress ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Function ◽  
Mitochondrial Dynamics ◽  
Mitochondrial Morphology ◽  
Therapeutic Approaches ◽  
The Impact ◽  
And Oxidative Stress

Mitochondria play a pivotal role in bioenergetics and respiratory functions, which are essential for the numerous biochemical processes underpinning cell viability. Mitochondrial morphology changes rapidly in response to external insults and changes in metabolic status via fission and fusion processes (so-called mitochondrial dynamics) that maintain mitochondrial quality and homeostasis. Damaged mitochondria are removed by a process known as mitophagy, which involves their degradation by a specific autophagosomal pathway. Over the last few years, remarkable efforts have been made to investigate the impact on the pathogenesis of Alzheimer’s disease (AD) of various forms of mitochondrial dysfunction, such as excessive reactive oxygen species (ROS) production, mitochondrial Ca2+ dyshomeostasis, loss of ATP, and defects in mitochondrial dynamics and transport, and mitophagy. Recent research suggests that restoration of mitochondrial function by physical exercise, an antioxidant diet, or therapeutic approaches can delay the onset and slow the progression of AD. In this review, we focus on recent progress that highlights the crucial role of alterations in mitochondrial function and oxidative stress in the pathogenesis of AD, emphasizing a framework of existing and potential therapeutic approaches.

scholarly journals Altered mitochondrial dynamics and function in APOE4-expressing astrocytes

2020 ◽  
Vol 11 (7) ◽  
Author(s):  
Eran Schmukler ◽  
Shira Solomon ◽  
Shira Simonovitch ◽  
Yona Goldshmit ◽  
Eya Wolfson ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Risk Factor ◽  
Transgenic Mice ◽  
Mitochondrial Function ◽  
Mitochondrial Dynamics ◽  
Major Risk Factor ◽  
Sporadic Alzheimer’S Disease ◽  
Dynamics And Function ◽  
And Function

Abstract APOE4 is a major risk factor for sporadic Alzheimer’s disease; however, it is unclear how it exerts its pathological effects. Others and we have previously shown that autophagy is impaired in APOE4 compared to APOE3 astrocytes, and demonstrated differences in the expression of mitochondrial dynamics proteins in brains of APOE3 and APOE4 transgenic mice. Here, we investigated the effect of APOE4 expression on several aspects of mitochondrial function and network dynamics, including fusion, fission, and mitophagy, specifically in astrocytes. We found that APOE3 and APOE4 astrocytes differ in their mitochondrial dynamics, suggesting that the mitochondria of APOE4 astrocytes exhibit reduced fission and mitophagy. APOE4 astrocytes also show impaired mitochondrial function. Importantly, the autophagy inducer rapamycin enhanced mitophagy and improved mitochondrial functioning in APOE4 astrocytes. Collectively, the results demonstrate that APOE4 expression is associated with altered mitochondrial dynamics, which might lead to impaired mitochondrial function in astrocytes. This, in turn, may contribute to the pathological effects of APOE4 in Alzheimer’s disease.

scholarly journals Correction of Mitochondrial Dysfunction by 4-Hydroxy-3,5-Ditretbutyl Cinnamic Acid in Experimental Alzheimer’s Disease Induced by Aβ Injection in Rats

2020 ◽  
Vol 27 (3) ◽  
pp. 313-325
Author(s):  
Dmitry Igorevich Pozdnyakov ◽  
Andrey Voronkov
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mitochondrial Dysfunction ◽  
Cinnamic Acid ◽  
Mitochondrial Function ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition ◽  
Morris Water Maze Test ◽  
Cellular Respiration ◽  
Β Amyloid

Background: Alzheimer’s disease is the main form of dementia, which affects more than46 million people every year. In the pathogenesis of Alzheimer’s disease, a significant roleplayed mitochondrial dysfunction, which is a promising pharmacotherapeutic target ofneuroprotective therapy. In this regard, this study aimed to evaluate the effect of the 4-hydroxy-3,5-ditretbutyl cinnamic acid on changes of mitochondrial function in experimental Alzheimer’sdisease induced by Aβ injection in rats. Methods: Alzheimer’s disease was modeled on Wistar rats by injecting a fragment of β-amyloid(Aß 1-42) into the CA1 part of the hippocampus. The test-compound (4-hydroxy-3,5-ditretbutylcinnamic acid, 100 mg/kg, per os) and the reference drugs (resveratrol, 20 mg/kg, per os andEGB671, 100 mg/kg, per os) were administered for 60 days after surgery. The restoration of amemorable trace in animals was evaluated in the Morris water maze test. The concentrationof β -amyloid, Tau-protein, and changes in parameters characterizing mitochondrial function(cellular respiration, concentration of mitochondrial ROS, activity of apoptosis reactions(caspase-3 and apoptosis induced factor) were also determined. Results: This study showed that the administration of 4-hydroxy-3,5-ditretbutyl cinnamic acidat a dose of 100 mg/kg (per os) in rats with reproduced Alzheimer’s disease contributed to thenormalization of mitochondrial respiratory function. It was expressed in the normalizationof aerobic metabolism, increased activity of respiratory complexes and stabilization ofmitochondrial membrane potential. Also, when animals were treated with 4-hydroxy-3,5-ditretbutyl cinnamic acid, there was a decrease in the concentration of intracellular calcium(by 39.7% (p<0.05)), the intensity of apoptosis reactions, and an increase of the latent time ofthe mitochondrial permeability transition pore opening (by 3.8 times (p<0.05)), and decreasesH2O2 concentration (by 21.2% (p<0.05)). Conclusion: In the course of this study, it was found that 4-hydroxy-3,5-ditretbutyl cinnamicacid exceeds the value of neuroprotective action in compared to the reference agents –resveratrol (20 mg/kg) and Ginkgo biloba extract (EGB671, 100 mg/kg).

scholarly journals Mitochondrial links between brain aging and Alzheimer’s disease

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Heather M. Wilkins ◽  
Russell H. Swerdlow
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Risk Factor ◽  
Mitochondrial Function ◽  
Brain Aging ◽  
Major Risk Factor ◽  
Background Information ◽  
Modeling Studies

AbstractAdvancing age is a major risk factor for Alzheimer’s disease (AD). This raises the question of whether AD biology mechanistically diverges from aging biology or alternatively represents exaggerated aging. Correlative and modeling studies can inform this question, but without a firm grasp of what drives aging and AD it is difficult to definitively resolve this quandary. This review speculates over the relevance of a particular hallmark of aging, mitochondrial function, to AD, and further provides background information that is pertinent to and provides perspective on this speculation.

scholarly journals Selenomethionine Improves Mitochondrial Function by Upregulating Mitochondrial Selenoprotein in a Model of Alzheimer’s Disease

2021 ◽  
Vol 13 ◽  
Author(s):  
Chen Chen ◽  
Yao Chen ◽  
Zhong-Hao Zhang ◽  
Shi-Zheng Jia ◽  
Yu-Bin Chen ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Membrane Potential ◽  
Energy Metabolism ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Membrane Potential ◽  
Neurofibrillary Tangles ◽  
Mitochondrial Function ◽  
Mitochondrial Membrane ◽  
Amyloid Plaques

Alzheimer’s disease (AD), the most common neurodegenerative disease in elderly humans, is pathologically characterized by amyloid plaques and neurofibrillary tangles. Mitochondrial dysfunction that occurs in the early stages of AD, which includes dysfunction in mitochondrial generation and energy metabolism, is considered to be closely associated with AD pathology. Selenomethionine (Se-Met) has been reported to improve cognitive impairment and reduce amyloid plaques and neurofibrillary tangles in 3xTg-AD mice. Whether Se-Met can regulate mitochondrial dysfunction in an AD model during this process remains unknown.In this study, the N2a-APP695-Swedish (N2aSW) cell and 8-month-old 3xTg-AD mice were treated with Se-Met in vitro and in vivo. Our study showed that the numbers of mitochondria were increased after treatment with Se-Met. Se-Met treatment also significantly increased the levels of NRF1 and Mfn2, and decreased those of OPA1 and Drp1. In addition, the mitochondrial membrane potential was significantly increased, while the ROS levels and apoptosis rate were significantly decreased, in cells after treatment with Se-Met. The levels of ATP, complex IV, and Cyt c and the activity of complex V were all significantly increased. Furthermore, the expression level of SELENO O was increased after Se-Met treatment. Thus, Se-Met can maintain mitochondrial dynamic balance, promote mitochondrial fusion or division, restore mitochondrial membrane potential, promote mitochondrial energy metabolism, inhibit intracellular ROS generation, and reduce apoptosis. These effects are most likely mediated via upregulation of SELENO O. In summary, Se-Met improves mitochondrial function by upregulating mitochondrial selenoprotein in these AD models.

Acer okamotoanum and isoquercitrin improve cognitive function via attenuation of oxidative stress in high fat diet- and amyloid beta-induced mice

2019 ◽  
Vol 10 (10) ◽  
pp. 6803-6814 ◽  
Author(s):  
Ji Hyun Kim ◽  
Sanghyun Lee ◽  
Eun Ju Cho
Keyword(s):  
Oxidative Stress ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Risk Factor ◽  
Cognitive Function ◽  
Amyloid Beta ◽  
High Fat Diet ◽  
High Fat ◽  
Acer Okamotoanum

High fat diet (HFD) and accumulation of amyloid beta (Aβ) are known as a risk factor of Alzheimer's disease. Acer okamotoanum and isoquercitrin improved cognition function against both HFD and Aβ accumulation by inhibiting oxidative stress.

scholarly journals Role of RALBP1 in Oxidative Stress and Mitochondrial Dysfunction in Alzheimer's Disease

2021 ◽  
Author(s):  
Sanjay Awasthi ◽  
Ashly Hindle ◽  
Neha Sawant ◽  
Mathew George ◽  
Murali Vijayan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Function ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Function ◽  
Sensory Function ◽  
Expression Of Genes

The purpose of our study is to understand the role of the Ralbp1 gene in oxidative stress (OS), mitochondrial dysfunction and cognition in Alzheimer's disease (AD) pathogenesis. The Ralbp1 gene encodes the 76 kDa protein Rlip (aka RLIP76). Previous studies have revealed its role in OS-related cancer. However, Rlip is transcriptionally regulated by EP300, a CREB-binding protein that is important for synaptic plasticity in the brain. Rlip functions as a stress-responsive/protective transporter of glutathione conjugates (GS-E) and xenobiotic toxins. OS causes rapid cellular accumulation of Rlip and its translocation from a tubulin-bound complex to the plasma membrane, mitochondria and nucleus. Therefore, Rlip may play an important role in maintaining cognitive function in the face of OS-related injury. This study is aimed to determine whether Rlip deficiency in mice is associated with AD-like cognitive and mitochondrial dysfunction. Brain tissue obtained from cohorts of wildtype and Rlip+/- mice were analyzed for OS markers, expression of genes that regulate mitochondrial fission/fusion, and synaptic integrity. We also examined mitochondrial ultrastructure in mouse brains obtained from these mice and further analyzed the impact of Rlip deficiency on gene networks of AD, aging, inhibition of stress-activated gene expression, mitochondrial function, and CREB signaling. Our studies revealed a significant increase in the levels of OS markers and alterations in the expression of genes and proteins involved in mitochondrial biogenesis, dynamics and synapses in brain tissues of these mice. Furthermore, we compared the cognitive function of wildtype and Rlip+/- mice. Behavioral, basic motor and sensory function tests in Rlip+/- mice revealed cognitive decline, similar to AD. Gene network analysis indicated dysregulation of stress-activated gene expression, mitochondrial function, and CREB signaling genes in the Rlip+/- mouse liver. Our results suggest that the Rlip deficiency-associated increase in OS and mitochondrial dysfunction could contribute to the development of OS-related AD processes. Therefore, the restoration of Rlip activity and endogenous cytoprotective mechanisms by pharmacological interventions is a novel approach to protect against AD.

scholarly journals RALBP1 in Oxidative Stress and Mitochondrial Dysfunction in Alzheimer’s Disease

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3113
Author(s):  
Sanjay Awasthi ◽  
Ashly Hindle ◽  
Neha A. Sawant ◽  
Mathew George ◽  
Murali Vijayan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Function ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Function ◽  
Gene Networks ◽  
Sensory Function ◽  
Expression Of Genes ◽  
The Impact

The purpose of our study is to understand the role of the RALBP1 gene in oxidative stress (OS), mitochondrial dysfunction and cognition in Alzheimer’s disease (AD) pathogenesis. The RALPB1 gene encodes the 76 kDa protein RLIP76 (Rlip). Rlip functions as a stress-responsive/protective transporter of glutathione conjugates (GS-E) and xenobiotic toxins. We hypothesized that Rlip may play an important role in maintaining cognitive function. The aim of this study is to determine whether Rlip deficiency in mice is associated with AD-like cognitive and mitochondrial dysfunction. Brain tissue obtained from cohorts of wildtype (WT) and Rlip+/− mice were analyzed for OS markers, expression of genes that regulate mitochondrial fission/fusion, and synaptic integrity. We also examined mitochondrial ultrastructure in brains obtained from these mice and further analyzed the impact of Rlip deficiency on gene networks of AD, aging, stress response, mitochondrial function, and CREB signaling. Our studies revealed a significant increase in the levels of OS markers and alterations in the expression of genes and proteins involved in mitochondrial biogenesis, dynamics and synapses in brain tissues from these mice. Furthermore, we compared the cognitive function of WT and Rlip+/− mice. Behavioral, basic motor and sensory function tests in Rlip+/− mice revealed cognitive decline, similar to AD. Gene network analysis indicated dysregulation of stress-activated gene expression, mitochondrial function and CREB signaling genes in the Rlip+/− mouse brain. Our results suggest that Rlip deficiency-associated increases in OS and mitochondrial dysfunction could contribute to the development or progression of OS-related AD processes.

scholarly journals Exercise-Induced Benefits for Alzheimer’s Disease by Stimulating Mitophagy and Improving Mitochondrial Function

2021 ◽  
Vol 13 ◽  
Author(s):  
Jiling Liang ◽  
Cenyi Wang ◽  
Hu Zhang ◽  
Jielun Huang ◽  
Juying Xie ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Function ◽  
Early Stage ◽  
Memory Loss ◽  
Later Life ◽  
Cognitive Capacity ◽  
Neurodegenerative Process

Neurons are highly specialized post-mitotic cells that are inherently dependent on mitochondria due to their higher bioenergetic demand. Mitochondrial dysfunction is closely associated with a variety of aging-related neurological disorders, such as Alzheimer’s disease (AD), and the accumulation of dysfunctional and superfluous mitochondria has been reported as an early stage that significantly facilitates the progression of AD. Mitochondrial damage causes bioenergetic deficiency, intracellular calcium imbalance and oxidative stress, thereby aggravating β-amyloid (Aβ) accumulation and Tau hyperphosphorylation, and further leading to cognitive decline and memory loss. Although there is an intricate parallel relationship between mitochondrial dysfunction and AD, their triggering factors, such as Aβ aggregation and hyperphosphorylated Tau protein and action time, are still unclear. Moreover, many studies have confirmed abnormal mitochondrial biosynthesis, dynamics and functions will present once the mitochondrial quality control is impaired, thus leading to aggravated AD pathological changes. Accumulating evidence shows beneficial effects of appropriate exercise on improved mitophagy and mitochondrial function to promote mitochondrial plasticity, reduce oxidative stress, enhance cognitive capacity and reduce the risks of cognitive impairment and dementia in later life. Therefore, stimulating mitophagy and optimizing mitochondrial function through exercise may forestall the neurodegenerative process of AD.

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