Mitophagy pathways and Alzheimer's disease: From pathogenesis to treatment

Impact of diet and exercise on mitochondrial quality and mitophagy in Alzheimer's disease

Alzheimer's disease (AD) is a devastating neurodegenerative disorder that affects millions of people worldwide. It is characterized by the accumulation of beta-amyloid and phosphorylated tau, synaptic damage, and mitochondrial abnormalities in the brain, leading to the progressive loss of cognitive function and memory. In AD, emerging research suggests that lifestyle factors such as a healthy diet and regular exercise may play a significant role in delaying the onset and progression of the disease. Mitochondria are often referred to as the powerhouse of the cell, as they are responsible for producing the energy to cells, including neurons to maintain cognitive function. Our article elaborates on how mitochondrial quality and function decline with age and AD, leading to an increase in oxidative stress and a decrease in ATP production. Decline in mitochondrial quality can impair cellular functions contributing to the development and progression of disease with the loss of neuronal functions in AD. This article also covered mitophagy, the process by which damaged or dysfunctional mitochondria are selectively removed from the cell to maintain cellular homeostasis. Impaired mitophagy has been implicated in the progression and pathogenesis of AD. We also discussed the impact of impaired mitophagy implicated in AD, as the accumulation of damaged mitochondria can lead to increased oxidative stress. We expounded how dietary interventions and exercise can help to improve mitochondrial quality, and mitochondrial function and enhance mitophagy in AD. A diet rich in antioxidants, polyphenols, and mitochondria-targeted small molecules has been shown to enhance mitochondrial function and protect against oxidative stress, particularly in neurons with aged and mild cognitively impaired subjects and AD patients. Promoting a healthy lifestyle, mainly balanced diet and regular exercise that support mitochondrial health, in an individual can potentially delay the onset and progression of AD. In conclusion, a healthy diet and regular exercise play a crucial role in maintaining mitochondrial quality and mitochondrial function, in turn, enhancing mitophagy and synaptic activities that delay AD in the elderly populations.

The role of mitochondrial dysfunction in the pathogenesis of Alzheimer's disease and future strategies for targeted therapy

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive cognitive decline, behavioral impairments, and psychiatric comorbidities. The pathogenesis of AD remains incompletely elucidated, despite advances in dominant hypotheses such as the β-amyloid (Aβ) cascade, tauopathy, cholinergic deficiency, and neuroinflammation mechanisms. However, these hypotheses inadequately explain the multifactorial nature of AD, which exposes limitations in our understanding of its mechanisms. Mitochondrial dysfunction is known to play a pivotal role in AD, and since patients exhibit intracellular mitochondrial dysfunction and structural changes in the brain at an early stage, correcting the imbalance of mitochondrial homeostasis and the cytopathological changes caused by it may be a potential target for early treatment of AD. Mitochondrial structural abnormalities accelerate AD pathogenesis. For instance, structural and functional alterations in the mitochondria-associated endoplasmic reticulum membrane (MAM) can disrupt intracellular Ca2⁺ homeostasis and cholesterol metabolism, consequently promoting Aβ accumulation. In addition, the overaccumulation of Aβ and hyperphosphorylated tau proteins can further damage neurons by disrupting mitochondrial integrity and mitophagy, thereby amplifying pathological aggregation and exacerbating neurodegeneration in AD. Furthermore, Aβ deposition and abnormal tau proteins can disrupt mitochondrial dynamics through dysregulation of fission/fusion proteins, leading to excessive mitochondrial fragmentation and subsequent dysfunction. Additionally, hyperphosphorylated tau proteins can impair mitochondrial transport, resulting in axonal dysfunction in AD. This article reviews the biological significance of mitochondrial structural morphology, dynamics, and mitochondrial DNA (mtDNA) instability in AD pathology, emphasizing mitophagy abnormalities as a critical contributor to AD progression. Additionally, mitochondrial biogenesis and proteostasis are critical for maintaining mitochondrial function and integrity. Impairments in these processes have been implicated in the progression of AD, further highlighting the multifaceted role of mitochondrial dysfunction in neurodegeneration. It further discusses the therapeutic potential of mitochondria-targeted strategies for AD drug development.

Autophagy: a double-edged sword in ischemia-reperfusion injury

Ischemia-reperfusion (I/R) injury describes the pathological process wherein tissue damage, initially caused by insufficient blood supply (ischemia), is exacerbated upon the restoration of blood flow (reperfusion). This phenomenon can lead to irreversible tissue damage and is commonly observed in contexts such as cardiac surgery and stroke, where blood supply is temporarily obstructed. During ischemic conditions, the anaerobic metabolism of tissues and organs results in compromised enzyme activity. Subsequent reperfusion exacerbates mitochondrial dysfunction, leading to increased oxidative stress and the accumulation of reactive oxygen species (ROS). This cascade ultimately triggers cell death through mechanisms such as autophagy and mitophagy. Autophagy constitutes a crucial catabolic mechanism within eukaryotic cells, facilitating the degradation and recycling of damaged, aged, or superfluous organelles and proteins via the lysosomal pathway. This process is essential for maintaining cellular homeostasis and adapting to diverse stress conditions. As a cellular self-degradation and clearance mechanism, autophagy exhibits a dualistic function: it can confer protection during the initial phases of cellular injury, yet potentially exacerbate damage in the later stages. This paper aims to elucidate the fundamental mechanisms of autophagy in I/R injury, highlighting its dual role in regulation and its effects on both organ-specific and systemic responses. By comprehending the dual mechanisms of autophagy and their implications for organ function, this study seeks to explore the potential for therapeutic interventions through the modulation of autophagy within clinical settings.

S-9-PAHSA Attenuates Aβ Accumulation and Improves Cognitive Deficits by Promoting Mitochondrial Autophagy in 5xFAD Mice

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder characterized by significant cognitive impairment and predominantly affects the elderly. With no effective cure available, research continues to explore novel therapeutic and preventive strategies. Recently, palmitic acid-hydroxystearic acids (PAHSAs), especially their stereochemistry S-configuration, have shown potential as a dietary supplement with anti-inflammatory and anti-diabetic properties. We previously found that one of the PAHSAs, 9-PAHSA, could improve cognitive impairment in the high-fat-diet mice, however, whether it has an equal effect on AD-like mice remains unclear. Since mitochondrial dysfunction is recognized as a significant pathological feature of AD, with impaired mitophagy leading to the accumulation of dysfunctional mitochondria, thus exacerbating disease progression, in this study, we evaluated the effects of the chiral isomer of 9-PAHSA, S-9-PAHSA, on cognitive dysfunction and mitochondrial dysfunction in 5xFAD mice. Three-month-old mice were treated with S-9-PAHSA 30 mg/kg in their drinking water for 3 months. Behavioral studies were conducted using the Morris Water Maze (MWM) and Y-maze tests, followed by assessments of amyloid-beta (Aβ) plaque deposition, neuronal apoptosis, and mitochondrial function. We found that S-9-PAHSA significantly enhanced spatial learning and memory abilities, reduced amyloid plaque deposition, decreased neuronal apoptosis, and improved mitochondrial homeostasis and autophagy in 5xFAD mice. These findings suggest that S-9-PAHSA holds promise as a supplementary preventive and therapeutic strategy for AD treatment.

Mitochondria-Related Genome-Wide Mendelian Randomization Identifies Putatively Causal Genes for Neurodegenerative Diseases

BACKGROUND

Mitochondrial dysfunction is increasingly recognized as a key factor in neurodegenerative diseases (NDDs), underscoring the therapeutic potential of targeting mitochondria-related genes. This study aimed to identify novel biomarkers and drug targets for these diseases through a comprehensive analysis that integrated genome-wide Mendelian randomization (MR) with genes associated with mitochondrial function.

METHODS

Using existing publicly available genome-wide association studies (GWAS) summary statistics and comprehensive data on 1136 mitochondria-related genes, we initially identified a subset of genes related to mitochondrial function that exhibited significant associations with NDDs. We then conducted colocalization and summary-data-based Mendelian randomization (SMR) analyses using expression quantitative trait loci (eQTL) to validate the causal role of these candidate genes. Additionally, we assessed the druggability of the encoded proteins to prioritize potential therapeutic targets for further exploration.

RESULTS

Genetically predicted levels of 10 genes were found to be significantly associated with the risk of NDDs. Elevated DMPK and LACTB2 levels were associated with increased Alzheimer's disease risk. Higher expression of NDUFAF2, BCKDK, and MALSU1, along with lower TTC19, raised Parkinson's disease risk. Higher ACLY levels were associated with both amyotrophic lateral sclerosis and multiple sclerosis (MS) risks, while decreased MCL1, TOP3A, and VWA8 levels raised MS risk. These genes primarily impact mitochondrial function and energy metabolism. Notably, several druggable protein targets identified are being explored for potential NDDs treatment.

CONCLUSIONS

This data-driven MR study demonstrated the causal role of mitochondrial dysfunction in NDDs. Additionally, this study identified candidate genes that could serve as potential pharmacological targets for the prevention and treatment of NDDs. © 2025 International Parkinson and Movement Disorder Society.

Aloe-Emodin Improves Mitophagy in Alzheimer's Disease via Activating the AMPK/PGC-1α/SIRT3 Signaling Pathway

BACKGROUND

Impaired mitophagy results in the accumulation of defective mitochondria that are unable to be cleared effectively in Alzheimer's disease (AD). Aloe-emodin (AE), a key component of the traditional Chinese medicine Rhubarb, exhibits neuroprotective effects against Alzheimer's disease, though the underlying mechanism remains unclear. Studying aloe-emodin's role in enhancing mitophagy is vital for improving cognitive function and reducing neuronal damage in Alzheimer's disease.

METHODS

The APP/PS1 double transgenic mice were adopted as models for AD to assess the effects of aloe-emodin upon cognitive function and its neuroprotective impact on hippocampal neurons. Additionally, we investigated the regulatory mechanisms of proteins within the aforementioned pathway, and the morphological characteristics of mitophagy-related proteins. An AD hippocampal neuron model was developed using Aβ25-35 to evaluate the mitochondrial function, the protein expression of such a pathway and the mitophagy. This approach aims to elucidate the effects and underlying mechanisms of aloe-emodin in relation to AD.

RESULTS

AE activates mitophagy in neurons, improves cognitive dysfunction, reduces hippocampal damage, and alleviates AD symptoms in model mice. AE activates the expression of AMPK, PGC-1α and SIRT3. Increased expression of SIRT3 in mitochondria promotes mitophagy and regulates the function of mitochondrial proteins. When mitochondrial autophagy is enhanced, the expression of Beclin1, LC3, P62, Parkin, and PINK1-related proteins changes. Further in vitro experiments showed that AE can enhance mitochondrial function in Alzheimer's disease cell models. The mitochondrial membrane potential, GSH, ROS and Ca2+ levels gradually recover, alleviating the pathological manifestations of AD. Knocking down SIRT3 leads to increased mitochondrial damage and a reduction in mitophagy in HT22 cells.

CONCLUSION

Experimental results show that AE can activate mitophagy through AMPK/PGC-1α/SIRT3 pathway, alleviate cognitive dysfunction in AD, and reduce damage to hippocampal neurons.

Unraveling mitochondrial dysfunction: comprehensive perspectives on its impact on neurodegenerative diseases

Neurodegenerative diseases represent a significant challenge to modern medicine, with their complex etiology and progressive nature posing hurdles to effective treatment strategies. Among the various contributing factors, mitochondrial dysfunction has emerged as a pivotal player in the pathogenesis of several neurodegenerative disorders. This review paper provides a comprehensive overview of how mitochondrial impairment contributes to the development of neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis, driven by bioenergetic defects, biogenesis impairment, alterations in mitochondrial dynamics (such as fusion or fission), disruptions in calcium buffering, lipid metabolism dysregulation and mitophagy dysfunction. It also covers current therapeutic interventions targeting mitochondrial dysfunction in these diseases.

Mitochondrial dysfunction in Alzheimer's disease: a key frontier for future targeted therapies

Alzheimer's disease (AD) is the most common neurodegenerative disorder, accounting for approximately 70% of dementia cases worldwide. Patients gradually exhibit cognitive decline, such as memory loss, aphasia, and changes in personality and behavior. Research has shown that mitochondrial dysfunction plays a critical role in the onset and progression of AD. Mitochondrial dysfunction primarily leads to increased oxidative stress, imbalances in mitochondrial dynamics, impaired mitophagy, and mitochondrial genome abnormalities. These mitochondrial abnormalities are closely associated with amyloid-beta and tau protein pathology, collectively accelerating the neurodegenerative process. This review summarizes the role of mitochondria in the development of AD, the latest research progress, and explores the potential of mitochondria-targeted therapeutic strategies for AD. Targeting mitochondria-related pathways may significantly improve the quality of life for AD patients in the future.

Mitochondrial Quality Control in Alzheimer's Disease: Insights from Caenorhabditis elegans Models

Alzheimer's disease (AD) is a complex neurodegenerative disorder that is classically defined by the extracellular deposition of senile plaques rich in amyloid-beta (Aβ) protein and the intracellular accumulation of neurofibrillary tangles (NFTs) that are rich in aberrantly modified tau protein. In addition to aggregative and proteostatic abnormalities, neurons affected by AD also frequently possess dysfunctional mitochondria and disrupted mitochondrial maintenance, such as the inability to eliminate damaged mitochondria via mitophagy. Decades have been spent interrogating the etiopathogenesis of AD, and contributions from model organism research have aided in developing a more fundamental understanding of molecular dysfunction caused by Aβ and toxic tau aggregates. The soil nematode C. elegans is a genetic model organism that has been widely used for interrogating neurodegenerative mechanisms including AD. In this review, we discuss the advantages and limitations of the many C. elegans AD models, with a special focus and discussion on how mitochondrial quality control pathways (namely mitophagy) may contribute to AD development. We also summarize evidence on how targeting mitophagy has been therapeutically beneficial in AD. Lastly, we delineate possible mechanisms that can work alone or in concert to ultimately lead to mitophagy impairment in neurons and may contribute to AD etiopathology.

From Plaques to Pathways in Alzheimer's Disease: The Mitochondrial-Neurovascular-Metabolic Hypothesis

Alzheimer's disease (AD) presents a public health challenge due to its progressive neurodegeneration, cognitive decline, and memory loss. The amyloid cascade hypothesis, which postulates that the accumulation of amyloid-beta (Aβ) peptides initiates a cascade leading to AD, has dominated research and therapeutic strategies. The failure of recent Aβ-targeted therapies to yield conclusive benefits necessitates further exploration of AD pathology. This review proposes the Mitochondrial-Neurovascular-Metabolic (MNM) hypothesis, which integrates mitochondrial dysfunction, impaired neurovascular regulation, and systemic metabolic disturbances as interrelated contributors to AD pathogenesis. Mitochondrial dysfunction, a hallmark of AD, leads to oxidative stress and bioenergetic failure. Concurrently, the breakdown of the blood-brain barrier (BBB) and impaired cerebral blood flow, which characterize neurovascular dysregulation, accelerate neurodegeneration. Metabolic disturbances such as glucose hypometabolism and insulin resistance further impair neuronal function and survival. This hypothesis highlights the interconnectedness of these pathways and suggests that therapeutic strategies targeting mitochondrial health, neurovascular integrity, and metabolic regulation may offer more effective interventions. The MNM hypothesis addresses these multifaceted aspects of AD, providing a comprehensive framework for understanding disease progression and developing novel therapeutic approaches. This approach paves the way for developing innovative therapeutic strategies that could significantly improve outcomes for millions affected worldwide.

Anti-oxidative-initiated cognitive impairment amelioration in Alzheimer's Disease model rats through preventive transcutaneous electrical acupoint stimulation

Background

Alzheimer's disease (AD) is a chronic and irreversible neurodegenerative disease. Oxidative stress emerges at the early AD stage. As a non-invasive therapy with few adverse reactions, transcutaneous electrical acupoint stimulation (TEAS) combines acupuncture points of traditional Chinese medicine (TCM) and electrical stimulation. This study aimed to investigate the amelioration effects of preventive TEAS treatment (P-TEAS) on cognitive impairment and oxidative stress in AD model rats.

Methods

The AD model was established via subcutaneous injections of D-galactose (D-gal, 120 mg/kg/d) into the back of neck for 9 weeks in Sprague Dawley (SD) rats to simulate the oxidative stress in the early AD stage. On the first day of the 10th week, Aβ_1-42 (1 μg/μl) was injected into the CA1 regions of the bilateral hippocampus. P-TEAS was synchronized from the first day of subcutaneous D-gal injections for 9 weeks.

Results

Empirical measurements showed that P-TEAS can improve the spatial memory ability of AD model rats in the Morris water maze. Superoxide dismutase (SOD) was upregulated in the P-TEAS group. Through the detection of the anti-oxidative stress signaling pathway, namely, Kelch-like ECH-associated protein 1 (Keap1)/ NFE2-related factor 2 (Nrf2), it was found that P-TEAS could promote Nrf2 entering into the nucleus and upregulating the production of protective factors heme oxygenase 1 (HO-1) and NADPH quinone oxidoreductase 1 (NQO1). It was also found that P-TEAS could downregulate the expressions of BCL2-associated X-protein (Bax), caspase 3, and caspase 9 to inhibit neuronal apoptosis.

Conclusions

P-TEAS has similar efficacy to electroacupuncture in preventing AD occurrence and development. P-TEAS is a new non-invasive intervention therapy for the prevention of AD.

Beyond the classical amyloid hypothesis in Alzheimer's disease: Molecular insights into current concepts of pathogenesis, therapeutic targets, and study models

Alzheimer's disease (AD) is one of the progressive neurodegenerative disorders and the most common cause of dementia in the elderly worldwide causing difficulties in the daily life of the patient. AD is characterized by the aberrant accumulation of β-amyloid plaques and tau protein-containing neurofibrillary tangles (NFTs) in the brain giving rise to neuroinflammation, oxidative stress, synaptic failure, and eventual neuronal cell death. The total cost of care in AD treatment and related health care activities is enormous and pharmaceutical drugs approved by Food and Drug Administration have not manifested sufficient efficacy in protection and therapy. In recent years, there are growing studies that contribute a fundamental understanding to AD pathogenesis, AD-associated risk factors, and pharmacological intervention. However, greater molecular process-oriented research in company with suitable experimental models is still of the essence to enhance the prospects for AD therapy and cell lines as a disease model are still the major part of this milestone. In this review, we provide an insight into molecular mechanisms, particularly the recent concept in gut-brain axis, vascular dysfunction and autophagy, and current models used in the study of AD. Here, we emphasized the importance of therapeutic strategy targeting multiple mechanisms together with utilizing appropriate models for the discovery of novel effective AD therapy. This article is categorized under: Neurological Diseases > Molecular and Cellular Physiology.

A Review of ApoE4 Interference Targeting Mitophagy Molecular Pathways for Alzheimer's Disease

Alzheimer's disease (AD) is one of the major worldwide causes of dementia that is characterized by irreversible decline in learning, memory loss, and behavioral impairments. Mitophagy is selective autophagy through the clearance of aberrant mitochondria, specifically for degradation to maintain energy generation and neuronal and synaptic function in the brain. Accumulating evidence shows that defective mitophagy is believed to be as one of the early and prominent features in AD pathogenesis and has drawn attention in the recent few years. APOE ε4 allele is the greatest genetic determinant for AD and is widely reported to mediate detrimental effects on mitochondria function and mitophagic process. Given the continuity of the physiological process, this review takes the mitochondrial dynamic and mitophagic core events into consideration, which highlights the current knowledge about the molecular alterations from an APOE-genotype perspective, synthesizes ApoE4-associated regulations, and the cross-talk between these signaling, along with the focuses on general autophagic process and several pivotal processes of mitophagy, including mitochondrial dynamic (DRP1, MFN-1), mitophagic induction (PINK1, Parkin). These may shed new light on the link between ApoE4 and AD and provide novel insights for promising mitophagy-targeted therapeutic strategies for AD.

Mitochondria bridge HIF signaling and ferroptosis blockage in acute kidney injury

Ferroptosis, a form of regulated cell death, plays an important role in acute kidney injury (AKI). Previous studies have shown that prolyl hydroxylase domain protein (PHD) inhibitors that activate HIF signaling provide strong protection against AKI, which is characterized by marked cell death. However, the relationship between PHD inhibition/HIF signaling and ferroptosis in AKI has not been elucidated. Here, we review recent studies to explore the issue. First, we will review the literature concerning the functions of HIF in promoting mitophagy, suppressing mitochondrial respiration and modulating redox homeostasis. Second, we will describe the current understanding of ferroptosis and its role in AKI, particularly from the perspective of mitochondrial dysfunction. Finally, we will discuss the possibility that mitochondria link PHD inhibition/HIF signaling and ferroptosis in AKI. In conclusion, we propose that HIF may protect renal cells against ferroptosis in AKI by reducing mitochondrial oxidative stress and damage.

The role of DRP1- PINK1-Parkin-mediated mitophagy in early cadmium-induced liver damage

Cadmium (Cd) is an important environmental pollutant that causes varying degrees of damage to multiple systems of the body. However, the specific mechanism of Cd-induced liver mitophagy remains unclear. In the present study, 5-week-old BALB/c mice and a mouse liver parenchyma cell line (AML12) were studied using a combination of in vivo and in vitro studies. We found that Cd damaged liver cells, destroy the structure and function of mitochondria, and increased the production of superoxide anions. This study further examined the effect of Cd on mitochondrial dynamics and mitophagy and showed that Cd increased mitochondrial division and induced mitophagy. The PINK1-Parkin pathway is a classical mitophagy pathway. Cd-induced mitophagy was inhibited after significantly knocking down Pink1. Mdivi-1 can effectively inhibit mitochondrial division. In this study, Mdivi-1 inhibited the expression of DRP1 and significantly inhibited the occurrence of mitophagy induced by Cd. We further examined the effect of Cd on mitophagy flux. Cd did not increase lysosomal colocalization with mitochondria. In summary, Cd increase the level of oxidative stress, destroy the structure and function of mitochondria, destroy the homeostasis of mitochondrial division and fusion, induce mitophagy through the PINK1-Parkin pathway. Mitophagy plays a protective role in early cadmium-induced liver damage.