Mitochondrial DNA damage and reactive oxygen species in neurodegenerative disease

Biological and translational attributes of mitochondrial DNA copy number: Laboratory perspective to clinical relevance

The mitochondrial DNA copy number (mtDNAcn) plays a vital role in cellular energy metabolism and mitochondrial health. As mitochondria are responsible for adenosine triphosphate production through oxidative phosphorylation, maintaining an appropriate mtDNAcn level is vital for the overall cellular function. Alterations in mtDNAcn have been linked to various diseases, including neurodegenerative disorders, metabolic conditions, and cancers, making it an important biomarker for understanding the disease pathogenesis. The accurate estimation of mtDNAcn is essential for clinical applications. Quantitative polymerase chain reaction and next-generation sequencing are commonly employed techniques with distinct advantages and limitations. Clinically, mtDNAcn serves as a valuable indicator for early diagnosis, disease progression, and treatment response. For instance, in oncology, elevated mtDNAcn levels in blood samples are associated with tumor aggressiveness and can aid in monitoring treatment efficacy. In neurodegenerative diseases such as Alzheimer’s and Parkinson’s, altered mtDNAcn patterns provide insights into disease mechanisms and progression. Understanding and estimating mtDNAcn are critical for advancing diagnostic and therapeutic strategies in various medical fields. As research continues to uncover the implications of mtDNAcn alterations, its potential as a clinical biomarker is likely to expand, thereby enhancing our ability to diagnose and manage complex diseases.

OmicsCam Enables Trimodal Profiling of Mitochondrial Genome Editing

Mitochondrial DNA (mtDNA) editing can generate cellular and animal models of mitochondrial genetic disorders and holds promise for future ex vivo and in vivo therapeutic applications. However, due to the quantitative nature of mitochondrion genetics, as more base-editing tools evolve, it is crucial to evaluate not only their efficiency and specificity on the sequence level but also the resulting molecular phenotypes. Here, we devised a novel Omics Carrier microcapsule, abbreviated as OmicsCam, that achieves homogeneous reactions within a heterogeneous carrier membrane, enabling highly efficient multistep biochemistry workflows. Incorporating magnetic beads into the carrier enables high-throughput automation. We demonstrated simultaneous trimodal assessment of mtDNA editing efficiency, postediting cellular transcriptome, and chromatin accessibility in minute cell samples containing as few as 25,000 cells. Applying OmicsCam to two TALE-DdCBE-edited human cell lines revealed that ND4 gene knockdown led to the downregulation of the mitochondrial oxidative phosphorylation pathway and changes in NF-Y transcription factor-associated histone modification pathways in the cell nucleus. Our study provides the most comprehensive analysis of mitochondrial gene editing efficiency and molecular phenotypes to date, which not only facilitates the establishment of mitochondrial genotype-molecular phenotype relationships but also helps assess the global safety of mitochondrial genome nucleases prior to clinical use.

Alternative NADH dehydrogenase: A complex I backup, a drug target, and a tool for mitochondrial gene therapy

Alternative NADH dehydrogenase, also known as type II NADH dehydrogenase (NDH-2), catalyzes the same redox reaction as mitochondrial respiratory chain complex I. Specifically, it oxidizes reduced nicotinamide adenine dinucleotide (NADH) while simultaneously reducing ubiquinone to ubiquinol. However, unlike complex I, this enzyme is non-proton pumping, comprises of a single subunit, and is resistant to rotenone. Initially identified in bacteria, fungi and plants, NDH-2 was subsequently discovered in protists and certain animal taxa including sea squirts. The gene coding for NDH-2 is also present in the genomes of some annelids, tardigrades, and crustaceans. For over two decades, NDH-2 has been investigated as a potential substitute for defective complex I. In model organisms, NDH-2 has been shown to ameliorate a broad spectrum of conditions associated with complex I malfunction, including symptoms of Parkinson's disease. Recently, lifespan extension has been observed in animals expressing NDH-2 in a heterologous manner. A variety of mechanisms have been put forward by which NDH-2 may extend lifespan. Such mechanisms include the activation of pro-longevity pathways through modulation of the NAD+/NADH ratio, decreasing production of reactive oxygen species (ROS) in mitochondria, or then through moderate increases in ROS production followed by activation of defense pathways (mitohormesis). This review gives an overview of the latest research on NDH-2, including the structural peculiarities of NDH-2, its inhibitors, its role in the pathogenicity of mycobacteria and apicomplexan parasites, and its function in bacteria, fungi, and animals.

Effects and Mechanisms of Extracellular Vesicles in Different Models of Acute Kidney Injury

Acute kidney injury (AKI) is a rapid decline in renal function caused by ischemia/reperfusion (I/R), renal toxic injury, and sepsis. While the precise molecular mechanisms underlying AKI are still under investigation, current therapeutic approaches remain insufficient. In recent years, there has been growing evidence that mesenchymal stem cells (MSCs) have great potential in accelerating renal repair after AKI in various preclinical models, while there has been extensive research on extracellular vesicles (EVs) as therapeutic mediators in AKI models, and they are considered to be superior to MSCs as new regenerative therapies. EVs are nanoparticles secreted by various types of cells under physiological and pathological conditions. EVs derived from various sources possess biomarker potential and play crucial roles in mediating cellular communication between kidney cells and other tissue cells by transmitting signal molecules. These vesicles play a direct and indirect role in regulating the pathophysiological mechanisms of AKI and contribute to the occurrence, development, treatment, and repair of AKI. In this review, we briefly outline the essential characteristics of EVs, focus on the multiple molecular mechanisms currently involved in the protection of EVs against different types of AKI, and further discuss the potential targets of EVs from different sources in the treatment of AKI. Finally, we summarized the deficiencies in the production and treatment of EVs and the current strategies for improvement.

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.

Therapeutic modulation of mitochondrial dynamics by agmatine in neurodegenerative disorders

Mitochondrial dysfunction is a pivotal factor in the pathogenesis of neurodegenerative disorders, driving neuronal degeneration through mechanisms involving oxidative stress, impaired energy production, and dysregulated calcium homeostasis. Agmatine, an endogenous polyamine derived from arginine, has garnered attention for its neuroprotective properties, including anti-inflammatory, anti-oxidative, and antiapoptotic effects. Recent studies have highlighted the potential of agmatine in preserving mitochondrial function and mitigating neurodegeneration, making it a promising candidate for therapeutic intervention. One of the key mechanisms by which agmatine exerts its neuroprotective effects is through the maintenance of mitochondrial homeostasis. Agmatine has been shown to modulate mitochondrial dynamics, promoting mitochondrial fusion and fission balance essential for cellular energy metabolism and signaling. Moreover, agmatine acts as a regulator of mitochondrial permeability transition pore (mPTP) opening, preventing excessive calcium influx and subsequent mitochondrial dysfunction. Despite promising findings, challenges such as optimizing agmatine's pharmacokinetics, determining optimal dosing regimens, and elucidating its precise molecular targets within mitochondria remain to be addressed. Future research directions should focus on developing targeted delivery systems for agmatine, investigating its interactions with mitochondrial proteins, and conducting well-designed clinical trials to evaluate its therapeutic efficacy and safety profile in neurodegenerative disorders. Overall, agmatine emerges as a novel therapeutic agent with the potential to modulate mitochondrial homeostasis and alleviate neurodegenerative pathology, offering new avenues for treating these debilitating conditions.

Exploring the interplay between mitochondrial dysfunction, early life adversity and bipolar disorder

OBJECTIVE

Mitochondria are essential for energy production and reactive oxygen species (ROS) generation, with changes in ROS levels or energy demands affecting mitochondrial DNA (mtDNA) copy numbers, indicating mitochondrial function. Early life adversity (ELA) affects mitochondrial dynamics, influencing long-term health. Both ELA and mitochondrial abnormalities have been independently associated with bipolar disorder (BD). This study aims to explore the complex interplay between mitochondrial dysfunction, ELA, and BD.

METHODS

The study included 60 participants diagnosed with BD and 66 healthy controls (HCs). Data were collected using the Childhood Trauma Questionnaire (CTQ), and leukocyte mtDNA copy number (MCN) was determined from blood samples.

RESULTS

The results indicated the CTQ sum scores were significantly higher in the BD group, reflecting greater exposure to ELA. In HCs, a marginally significant nonlinear relationship between the square of the CTQ sum score and MCN was found. Further analysis demonstrated a significant interaction between ELA and BD on MCN (p = 0.023), highlighting a critical connection between ELA and mitochondrial dysfunction in BD and reinforcing its biological underpinnings.

CONCLUSIONS

Future treatments for BD might target mitochondrial dysfunctions related to chronic stress, with potential pharmaceuticals designed to address these issues and mitigate the negative effects of chronic stress.

Mitochondrial DNA variants in the pathogenesis and metabolic alterations of diabetes mellitus

Mitochondrial DNA (mtDNA) variants considerably affect diabetes mellitus by disturbing mitochondrial function, energy metabolism, oxidative stress response, and even insulin secretion. The m.3243 A > G variants is associated with maternally inherited diabetes and deafness (MIDD), where early onset diabetes and hearing loss are prominent features. Other types of mtDNA variants involve genes ND4 and tRNA Ala genes that increase susceptibility to type 2 diabetes. Understanding these variants will provide a basis for developing targeted therapy to improve mitochondrial function and metabolic health. This article reviews the impact of mtDNA variants in diabetes, specifically with regards to the m.3243 A > G variant effects on mitochondrial function and insulin secretion and other mtDNA variants that contribute to diabetes susceptibility, particularly ND4 and tRNA Ala gene variants. Data from extant literature were synthesised to obtain an understanding of how mtDNA variants affect diabetes pathogenesis. The main defect for MIDD is the m.3243 A > G variant, which comprises enhanced susceptibility to metabolic syndrome and type 2 diabetes, followed by mitochondrial dysfunction, insulin resistance, and beta-cell dysfunction. Other mtDNA variants have also been reported to enhance diabetes susceptibility through mitochondrial dysfunction and insulin resistance. Increased production of reactive oxygen species (ROS) resulting from mitochondrial malfunction adds to metabolic and tissue damage. This happens in tissues crucial to glucose homeostasis, and it represents an important contribution of mitochondrial dysfunction to metabolic disturbances in diabetes. These mechanisms would underlie the rationale for developing targeted therapies to preserve mitochondrial function and, hence improve the metabolic health of diabetic patients.

Navigating the Complex Pathogenesis of Acute Kidney Injury: Exploring Macrophage Dynamics, Mitochondrial Dysfunction, and Ferroptosis Pathways

Acute kidney injury, a rapid decline in kidney function coupled with physiological and homeostatic perturbations, is an independent risk factor for both short-term and long-term health outcomes. As incidence of acute kidney injury continues to rise globally, the significant clinical and economic challenge of acute kidney injury underscores the need for its prompt recognition and application of novel and germane strategies to reduce its severity and facilitate recovery. Understanding the multifaceted cascade of events engaged in pathogenesis of acute kidney injury is pivotal for the development of effective preventive and therapeutic strategies. To facilitate an in-depth discussion on emerging therapeutic targets, this review will examine the role of macrophages in kidney injury and repair, explore the alterations in mitochondrial biogenesis dynamics induced by acute kidney injury, and provide insights into the molecular mechanisms underlying the contribution of ferroptosis to kidney injury.

Preclinical studies of natural flavonoids in inflammatory bowel disease based on macrophages: a systematic review with meta-analysis and network pharmacology

Flavonoid is a category of bioactive polyphenolic compounds that are extensively distributed in plants with specific pharmacological properties, such as anti-inflammatory and anti-oxidant. Importantly, natural flavonoids have shown the protected function on the dextran sulfate sodium (DSS)-induced colitis in animals and lipopolysaccharides (LPS)-induced inflammatory response in macrophages. The purpose of this systematic review is to explore the efficacy of natural flavonoids in animal models of IBD (inflammatory bowel disease) and potential mechanisms in macrophages by meta-analysis and network pharmacology in preclinical studies. Relevant foundation studies were searched from January 2010 to November 2023 in databases like PubMed, Elsevier ScienceDirect, and Web of Science. Then, OriginPro software was used to extract values from images, and the analysis was performed using Review Manager 5.3. The retrieved data was analyzed according to the fixed-effects model and random-effects model. Subsequently, heterogeneity was evaluated using the I2 statistics. Lastly, network pharmacology was applied to confirm mechanisms of natural flavonoids on IBD. According to the results of meta-analysis, we found the natural flavonoids exhibited powerful therapeutic effects against IBD, which not only reversed colonic shortness (WMD = 1.33, 95% CI (1.07, 1.59), P < 0.00001), but also reduced histological score (SMD =  - 2.66, 95% CI (- 3.77, - 1.95), P < 0.00001) between natural flavonoid treatment groups compared with the experimental IBD model. Furthermore, treatment with natural flavonoids decreased the levels of tumor necrosis factor-α (TNF-α) in macrophages. Mechanistically, our summarized data substantiate that natural flavonoids alleviate LPS-induced M1 macrophage polarization, anti-oxidant, anti-inflammatory, maintain intestinal barrier, and inhibit the activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome in macrophages. Moreover, the results of network pharmacology also support this. This systematic review demonstrated the efficiency of natural flavonoids in treating IBD in preclinical research by meta-analysis and network pharmacology, which offered supporting evidence for clinical trial implementation. However, some limitations remain present, such as technique quality shortage, missed reports on account of negative results, failure to count sample size, and the risk of bias.

Product of Traditional Chinese Medicine Longgui Yangxinwan Protects the Human Body from Altitude Sickness Damage by Reducing Oxidative Stress and Preventing Mitochondrial Dysfunction

Yu Liu, Zhengyang Zhang, Yongting Luo, Peng An, Jingyi Qi, Xu Zhang, Shuaishuai Zhou, Yongzhi Li, Chong Xu, Junjie Luo, and Jiaping Wang. Product of traditional Chinese medicine longgui yangxinwan protects the human body from altitude sickness damage by reducing oxidative stress and preventing mitochondrial dysfunction. High Alt Med Biol. 26:20-29, 2025. Background: Plateau reaction, caused by high-altitude exposure, results in symptoms like headaches, dyspnea, palpitations, fatigue, shortness of breath, and insomnia due to reduced oxygen levels. Mitochondria are crucial for high-altitude acclimatization as they regulate oxygen metabolism and cellular energy, reducing oxidative stress and maintaining bodily functions. Methods: The study participants were randomly divided into placebo group, Rhodiola group and longgui yangxinwan (Original name: taikong yangxinwan) group, with 20 people in each group. Three groups of subjects were sampled at three time points (PI: pre-intervention; P-D1: high-altitude day 1; P-D7: high-altitude day 7), and blood pressure, blood oxygen, heart rate, hemoglobin, and red blood cell count were measured. The ATP content, mitochondrial DNA copy number, expression of mitochondria-related genes, reactive oxygen species (ROS), glutathione peroxidase (GSH-PX) and malondialdehyde (MDA) levels, and mitochondrial morphology were measured in blood at each time point. Results: Our study results demonstrate that longgui yangxinwan keeps the selected human physiological indicators stable and prevents mitochondrial dysfunction in the high altitude. Mechanically, longgui yangxinwan decreases the level of ROS in human serum, whereas increases the activity of the antioxidant enzyme GSH-PX. At high-altitude day 1 (P-D1) and high-altitude day 7 (P-D7), ROS in the placebo group were 1.5 and 2.2-fold higher than those of the longgui yangxinwan group, respectively. In addition, longgui yangxinwan enhances ATP production capacity, restores the levels of mitochondrial respiratory chain complexes, and effectively maintains mitochondrial morphology and integrity. At P-D1 and P-D7, the ATP levels in the longgui yangxinwan group were 19-fold and 26-fold higher than those in the placebo group, respectively. Conclusions: Our study highlights longgui yangxinwan as a potential drug for protecting humans from high-altitude damage by reducing oxidative stress and preventing mitochondrial dysfunction.

The Role of Mitochondrial Quality Control in Liver Diseases: Dawn of a Therapeutic Era

The liver is a vital metabolic organ that detoxifies substances, produces bile, stores nutrients, and regulates versatile metabolic processes. Maintaining normal liver cell function requires the prompt and delicate modulation of mitochondrial quality control (MQC), which encompasses a spectrum of processes such as mitochondrial fission, fusion, biogenesis, and mitophagy. Recent studies have shown that disruptions to this homeostatic status are closely linked to the advent and progression of a variety of acute and chronic liver diseases, including but not limited to alcohol-associated liver disease and metabolic dysfunction-associated fatty liver disease. However, the explicit mechanisms by which mitochondrial dysfunction impacts inflammatory pathways and cell death in the context of liver diseases remain unclear. In this narrative review, we provide a detailed description of MQC, analyze the mechanisms underpinning mitochondrial dysfunction induced by different detrimental insults, and further elucidate how imbalanced/disrupted MQC promotes the progression and aggravation of liver diseases, ultimately shedding light on the mitochondrion-centric therapeutic strategies for these pathophysiological entities.

Mitochondrial Alterations, Oxidative Stress, and Therapeutic Implications in Alzheimer's Disease: A Narrative Review

The relationship between aging, mitochondrial dysfunction, neurodegeneration, and the onset of Alzheimer's disease (AD) is a complex area of study. Aging is the primary risk factor for AD, and it is associated with a decline in mitochondrial function. This mitochondrial dysfunction is believed to contribute to the neurodegenerative processes observed in AD. Neurodegeneration in AD is characterized by the progressive loss of synapses and neurons, particularly in regions of the brain involved in memory and cognition. It is hypothesized that mitochondrial dysfunction plays a pivotal role by disrupting cellular energy metabolism and increasing the production of reactive oxygen species (ROS), which can damage cellular components and exacerbate neuronal loss. Despite extensive research, the precise molecular pathways linking mitochondrial dysfunction to AD pathology are not fully understood. Various hypotheses have been proposed, including the mitochondrial cascade hypothesis, which suggests that mitochondrial dysfunction is an early event in AD pathogenesis that triggers a cascade of cellular events leading to neurodegeneration. With this narrative review, we aim to summarize some specific issues in the literature on mitochondria and their involvement in AD onset, with a focus on the development of therapeutical strategies targeting the mitochondria environment and their potential application for the treatment of AD itself.

Targeting Mitochondrial Dysfunction in Cerebral Ischemia: Advances in Pharmacological Interventions

The study of mitochondrial dysfunction has become increasingly pivotal in elucidating the pathophysiology of various cerebral pathologies, particularly neurodegenerative disorders. Mitochondria are essential for cellular energy metabolism, regulation of reactive oxygen species (ROS), calcium homeostasis, and the execution of apoptotic processes. Disruptions in mitochondrial function, driven by factors such as oxidative stress, excitotoxicity, and altered ion balance, lead to neuronal death and contribute to cognitive impairments in several brain diseases. Mitochondrial dysfunction can arise from genetic mutations, ischemic events, hypoxia, and other environmental factors. This article highlights the critical role of mitochondrial dysfunction in the progression of neurodegenerative diseases and discusses the need for targeted therapeutic strategies to attenuate cellular damage, restore mitochondrial function, and enhance neuroprotection.

The Role of Oligodendrocyte Lineage Cells in the Pathogenesis of Alzheimer's Disease

Alzheimer's disease (AD) is a central nervous system degenerative disease with a stealthy onset and a progressive course characterized by memory loss, cognitive dysfunction, and abnormal psychological and behavioral symptoms. However, the pathogenesis of AD remains elusive. An increasing number of studies have shown that oligodendrocyte progenitor cells (OPCs) and oligodendroglial lineage cells (OLGs), especially OPCs and mature oligodendrocytes (OLGs), which are derived from OPCs, play important roles in the pathogenesis of AD. OLGs function mainly by myelinating axons, transmitting electrical signals, and regulating neural development. In addition to myelin, OPCs and OLGs can also participate in AD pathogenesis in other ways. This review summarizes the mechanisms by which OPCs and OLGs affect myelin formation, oxidative stress, neuroinflammation, the blood-brain barrier, synaptic function, and amyloid-beta protein and further elucidates the mechanisms by which oligodendrocyte lineage cells participate in AD pathogenesis and treatment, which is highly important for clarifying the pathogenesis of AD, clinical treatment, and prevention.

Nitrate-Nitrite-Nitric Oxide Pathway, Oxidative Stress, and Fertility Outcomes in Morbidly Obese Women Following Bariatric Surgery: A Systematic Review

Obesity reduces nitric oxide (NO) production due to endothelial nitric oxide synthase (eNOS) dysfunction, resulting in oxidative stress, mitochondrial dysfunction, and chronic inflammation. These factors have a negative impact on reproductive health, including oocyte quality, endometrial receptivity, and embryo implantation. When oxidative stress affects eNOS function, the nitrate-nitrite-nitric oxide (NO3-NO2-NO) pathway provides an alternate route for NO production. Bariatric surgery has been found to restore NO production, reduce oxidative stress, and improve fertility in morbidly obese women. This review investigates the molecular mechanisms by which bariatric surgery affects eNOS activity, the NO3-NO2-NO pathway, and oxidative stress reduction, with an emphasis on intracellular activities including mitochondrial biogenesis and NO production. A systematic review employing PRISMA criteria included articles published between 2000 and 2024 from PubMed, Scopus, and Embase that investigated NO3-NO2 pathways, oxidative stress markers, hormonal alterations, and reproductive outcomes in morbidly obese women following bariatric surgery. After evaluating 1542 studies, 11 were selected for the final analysis. Results showed a 45% increase in NO3-NO2 levels (p < 0.001), a 35% reduction in oxidative stress indicators (p < 0.01), a 60% increase in pregnancy rates, and a 50% increase in spontaneous ovulation rates following surgery. These benefits were connected to improved mitochondrial function and endometrial receptivity as a result of reduced oxidative stress and inflammation. The NO3-NO2-NO route is critical in compensating for lower NO generation under oxidative stress and hypoxia, and bariatric surgery significantly improves this pathway to optimize blood flow, mitochondrial function, and reproductive results.

Gut microbiome synthesizes important core metabolites to prevent cognitive decline and mitigate onset and progression of Alzheimer's disease

Background

This study explores how gut metabolites, produced through bacterial metabolism in the gut, influence neurological conditions like Alzheimer's disease (AD). Key metabolites such as succinate and short-chain fatty acids signal through the autonomic nervous system and can cross the blood-brain barrier, impacting central nervous system functions.

Objective

The aim is to examine the role of the gut microbiota in compensating for metabolic deficiencies in AD. By analyzing wild-type (WT) and APP/PS1 mice, the study investigates how the microbiome affects key metabolic processes and whether it can slow AD progression.

Methods

High-throughput sequencing data from the gut microbiomes of APP/PS1 transgenic AD model mice and age-matched WT C57BL/6 male mice were analyzed for microbial and metabolite profiles.

Results

Alpha and beta diversity analyses showed differences in microbial composition between groups. Partial least squares discriminant analysis and Anosim confirmed distinct microbiome profiles in WT and APP/PS1 mice. At the genus level, Vescimonas was more abundant in WT mice, while Odoribacter, Lacrimispora, Helicobacter, Bacteroides, and Alloprevotella were more prevalent in APP/PS1 mice.

Conclusions

While taxonomic differences did not directly link specific microorganisms to AD, functional analysis identified key metabolites-acetyl-CoA, glucose, succinate, lipids, choline, and acetylcholine-that may alleviate energy deficits and synaptic dysfunction. This study suggests that the microbiome may help compensate for AD-related impairments, opening avenues for microbiome-based therapies.

A Commentary on Mitochondrial Dysfunction and Compromised DNA Repair in Neurodegeneration: The Emerging Role of FUS in ALS

Mitochondrial dysfunction plays a pivotal role in the progression of neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), Alzheimer's, and Parkinson's disease. Recent discoveries have highlighted the involvement of DNA damage and repair processes, particularly mitochondrial DNA (mtDNA) damage, in these conditions. This commentary reflects on our recent findings, demonstrating the RNA/DNA binding protein fused in sarcoma (FUS)'s crucial role in maintaining mtDNA integrity through interactions with mitochondrial DNA ligase IIIα (mtLig3). Our studies provide direct evidence of increased mtDNA damage in ALS-linked FUS mutant cells, emphasizing the potential of targeting DNA repair pathways to mitigate neurodegeneration. Furthermore, the restoration of mitochondrial function through targeted expression of human DNA ligase 1 (Lig1) in FUS mutant models showcases the therapeutic promise of DNA repair mechanisms in neurodegenerative diseases. These insights offer new molecular understanding and open up future avenues for therapeutic interventions, particularly in FUS-associated ALS and related disorders.

Methods and applications of genome-wide profiling of DNA damage and rare mutations

DNA damage is a threat to genome integrity and can be a cause of many human diseases, owing to either changes in the chemical structure of DNA or conversion of the damage into a mutation, that is, a permanent change in DNA sequence. Determining the exact positions of DNA damage and ensuing mutations in the genome are important for identifying mechanisms of disease aetiology when characteristic mutations are prevalent and probably causative in a particular disease. However, this approach is challenging particularly when levels of DNA damage are low, for example, as a result of chronic exposure to environmental agents or certain endogenous processes, such as the generation of reactive oxygen species. Over the past few years, a comprehensive toolbox of genome-wide methods has been developed for the detection of DNA damage and rare mutations at single-nucleotide resolution in mammalian cells. Here, we review and compare these methods, describe their current applications and discuss future research questions that can now be addressed.

Integrated approach to reducing polypharmacy in older people: exploring the role of oxidative stress and antioxidant potential therapy

Increased life expectancy, attributed to improved access to healthcare and drug development, has led to an increase in multimorbidity, a key contributor to polypharmacy. Polypharmacy is characterised by its association with a variety of adverse events in the older persons. The mechanisms involved in the development of age-related chronic diseases are largely unknown; however, altered redox homeostasis due to ageing is one of the main theories. In this context, the present review explores the development and interaction between different age-related diseases, mainly linked by oxidative stress. In addition, drug interactions in the treatment of various diseases are described, emphasising that the holistic management of older people and their pathologies should prevail over the individual treatment of each condition.

Forced Overexpression and Knockout Analysis of SLC30A and SLC39A Family Genes Suggests Their Involvement in Establishing Resistance to Cisplatin in Human Cancer Cells

The metabolism of zinc and manganese plays a pivotal role in cancer progression by mediating cancer cell growth and metastasis. The SLC30A family proteins SLC30A3 and SLC30A10 mediate the efflux of zinc, manganese, and probably other transition element ions outside the cytoplasm to the extracellular space or into intracellular membrane compartments. The SLC39A family members SLC39A8 and SLC39A14 are their functional antagonists that transfer these ions into the cytoplasm. Recently, the SLC30A10 gene was suggested as a promising methylation biomarker of colorectal cancer. Here, we investigated whether forced overexpression or inactivation of SLC30A and SLC39A family genes has an impact on the phenotype of cancer cells and their sensitivity to cancer therapeutics. In the human colon adenocarcinoma HCT-15 and duodenal adenocarcinoma HuTu80 cell lines, we generated clones with knockouts of the SLC39A8 and SLC39A14 genes and forced overexpression of the SLC30A3, SLC30A10, and SLC39A8 genes. Gene expression in the mutant and control cells was assessed by RNA sequencing. The cell growth rate, mitochondrial activity, zinc accumulation, and sensitivity to the drugs cetuximab and cisplatin were investigated in functional tests. Overexpression or depletion of SLC30A or SLC39A family genes resulted in the deep reshaping of intracellular signaling and provoked hyperactivation of mitochondrial respiration. Variation in the expression of the SLC30A/SLC39A genes did not increase the sensitivity to cetuximab but significantly altered the sensitivity to cisplatin: overexpression of SLC30A10 resulted in an ~2.7-4 times increased IC50 of cisplatin, and overexpression of SLC30A3 resulted in an ~3.3 times decreased IC50 of cisplatin. The SLC30A/SLC39A genes should be considered as potential cancer drug resistance biomarkers and putative therapeutic targets.

Mitochondrial destabilization in tendinopathy and potential therapeutic strategies

Tendinopathy is a prevalent aging-related disorder characterized by pain, swelling, and impaired function, often resulting from micro-scarring and degeneration caused by overuse or trauma. Current interventions for tendinopathy have limited efficacy, highlighting the need for innovative therapies. Mitochondria play an underappreciated and yet crucial role in tenocytes function, including energy production, redox homeostasis, autophagy, and calcium regulation. Abnormalities in mitochondrial function may lead to cellular senescence. Within this context, this review provides an overview of the physiological functions of mitochondria in tendons and presents current insights into mitochondrial dysfunction in tendinopathy. It also proposes potential therapeutic strategies that focus on targeting mitochondrial health in tenocytes. These strategies include: (1) utilizing reactive oxygen species (ROS) scavengers to mitigate the detrimental effects of aberrant mitochondria, (2) employing mitochondria-protecting agents to reduce the production of dysfunctional mitochondria, and (3) supplementing with exogenous normal mitochondria. In conclusion, mitochondria-targeted therapies hold great promise for restoring mitochondrial function and improving outcomes in patients with tendinopathy. The translational potential of this article: Tendinopathy is challenging to treat effectively due to its poorly understood pathogenesis. This review thoroughly analyzes the role of mitochondria in tenocytes and proposes potential strategies for the mitochondrial treatment of tendinopathy. These findings establish a theoretical basis for future research and the clinical translation of mitochondrial therapy for tendinopathy.

Mechanisms and therapeutic targets of carbon monoxide poisoning: A focus on reactive oxygen species

Carbon monoxide (CO) poisoning presents a substantial public health challenge that necessitates the identification of its pathological mechanisms and therapeutic targets. CO toxicity arises from tissue hypoxia-ischemia secondary to carboxyhemoglobin formation, and cellular damage mediated by CO at the cellular level. The mitochondria are the major targets of neuronal damage caused by CO. Under normal physiological conditions, mitochondria produce reactive oxygen species (ROS), which are byproducts of aerobic metabolism. While low ROS levels are crucial for essential cellular functions, including signal transduction, differentiation, responses to hypoxia and immunity, transcriptional regulation, and autophagy, excess ROS become pathological and exacerbate CO poisoning. This review presents the evidence of elevated ROS being associated with the progression of CO poisoning. Antioxidant treatments targeting ROS removal have been proven effective in mitigating CO poisoning, underscoring their therapeutic potential. In this review, we highlight the latest advances in the understanding of the role and the clinical implications of ROS in CO poisoning. We focus on cellular sources of ROS, the molecular mechanisms underlying mitochondrial oxidative stress, and potential therapeutic strategies for targeting ROS in CO poisoning.

Exosome-associated mitochondrial DNA in late-life depression: Implications for cognitive decline in older adults

BACKGROUND

Disrupted cellular communication, inflammatory responses and mitochondrial dysfunction are consistently observed in late-life depression (LLD). Exosomes (EXs) mediate cellular communication by transporting molecules, including mitochondrial DNA (EX-mtDNA), playing critical role in immunoregulation alongside tumor necrosis factor (TNF). Changes in EX-mtDNA are indicators of impaired mitochondrial function and might increase vulnerability to adverse health outcomes. Our study examined EX-mtDNA levels and integrity, exploring their associations with levels of TNF receptors I and II (TNFRI and TNFRII), and clinical outcomes in LLD.

METHODS

Ninety older adults (50 LLD and 40 controls (HC)) participated in the study. Blood was collected and exosomes were isolated using size-exclusion chromatography. DNA was extracted and EX-mtDNA levels and deletion were assessed using qPCR. Plasma TNFRI and TNFRII levels were quantified by multiplex immunoassay. Correlation analysis explored relationships between EX-mtDNA, clinical outcomes, and inflammatory markers.

RESULTS

Although no differences were observed in EX-mtDNA levels between groups, elevated levels correlated with poorer cognitive performance (r = -0.328, p = 0.002) and increased TNFRII levels (r = 0.367, p = 0.004). LLD exhibited higher deletion rates (F(83,1) = 4.402, p = 0.039), with a trend remaining after adjusting for covariates (p = 0.084). Deletion correlated with poorer cognitive performance (r = -0.335, p = 0.002). No other associations were found.

LIMITATION

Cross-sectional study with a small number of participants from a specialized geriatric psychiatry treatment center.

CONCLUSION

Our findings suggest that EX-mtDNA holds promise as an indicator of cognitive outcomes in LLD. Additional research is needed to further comprehend the role of EX-mtDNA levels/integrity in LLD, paving the way for its clinical application in the future.

Mitochondrial signaling pathways and their role in cancer drug resistance

Mitochondria, traditionally known as cellular powerhouses, now emerge as critical signaling centers influencing cancer progression and drug resistance. The review highlights the role that apoptotic signaling, DNA mutations, mitochondrial dynamics and metabolism play in the development of resistance mechanisms and the advancement of cancer. Targeted approaches are discussed, with an emphasis on managing mitophagy, fusion, and fission of the mitochondria to make resistant cancer cells more susceptible to traditional treatments. Additionally, metabolic reprogramming can be used to effectively target metabolic enzymes such GLUT1, HKII, PDK, and PKM2 in order to avoid resistance mechanisms. Although there are potential possibilities for therapy, the complex structure of mitochondria and their subtle role in tumor development hamper clinical translation. Novel targeted medicines are put forth, providing fresh insights on combating drug resistance in cancer. The study also emphasizes the significance of glutamine metabolism, mitochondrial respiratory complexes, and apoptotic pathways as potential targets to improve treatment effectiveness against drug-resistant cancers. Combining complementary and nanoparticle-based techniques to target mitochondria has demonstrated encouraging results in the treatment of cancer, opening doors to reduce resistance and enable individualized treatment plans catered to the unique characteristics of each patient. Suggesting innovative approaches such as drug repositioning and mitochondrial drug delivery to enhance the efficacy of mitochondria-targeting therapies, presenting a pathway for advancements in cancer treatment. This thorough investigation is a major step forward in the treatment of cancer and has the potential to influence clinical practice and enhance patient outcomes.

Regulation of Type I Interferon and Autophagy in Immunity against Mycobacterium Tuberculosis: Role of CGAS and STING1

Mycobacterium tuberculosis (M. tb) is a significant intracellular pathogen responsible for numerous infectious disease-related deaths worldwide. It uses ESX-1 T7SS to damage phagosomes and to enter the cytosol of host cells after phagocytosis. During infection, M. tb and host mitochondria release dsDNA, which activates the CGAS-STING1 pathway. This pathway leads to the production of type I interferons and proinflammatory cytokines and activates autophagy, which targets and degrades bacteria within autophagosomes. However, the role of type I IFNs in immunity against M. tb is controversial. While previous research has suggested a protective role, recent findings from cgas-sting1 knockout mouse studies have contradicted this. Additionally, a study using knockout mice and non-human primate models uncovered a new mechanism by which neutrophils recruited to lung infections form neutrophil extracellular traps. Activating plasmacytoid dendritic cells causes them to produce type I IFNs, which interfere with the function of interstitial macrophages and increase the likelihood of tuberculosis. Notably, M. tb uses its virulence proteins to disrupt the CGAS-STING1 signaling pathway leading to enhanced pathogenesis. Investigating the CGAS-STING1 pathway can help develop new ways to fight tuberculosis.

Cross-Species Studies Reveal That Dysregulated Mitochondrial Gene Expression and Electron Transport Complex I Activity Are Crucial for Sarcopenia

The significance of complex I of the electron transport chain (ETC) in the aging process is widely acknowledged; however, its specific impact on the development of sarcopenia in muscle remains poorly understood. This study elucidated the correlation between complex I inhibition and sarcopenia by conducting a comparative analysis of skeletal muscle gene expression in sarcopenia phenotypes from rats, mice, and humans. Our findings reveal a common mechanistic link across species, particularly highlighting the correlation between the suppression of complex I of ETC activity and dysregulated mitochondrial transcription and translation in sarcopenia phenotypes. Additionally, we observed macrophage dysfunction alongside abnormal metabolic processes within skeletal muscle tissues across all species, implicating their pathogenic role in the onset of sarcopenia. These discoveries underscore the importance of understanding the shared mechanisms associated with complex I of ETC in sarcopenia development. The identified correlations provide valuable insights into potential targets for therapeutic interventions aimed at mitigating the impact of sarcopenia, a condition with substantial implications for aging populations.

Sirtuin 1 as a potential biomarker of undernutrition in the elderly: a narrative review

Undernutrition and inflammatory processes are predictors of early mortality in the elderly and require a rapid and accurate diagnosis. Currently, there are laboratory markers for assessing nutritional status, but new markers are still being sought. Recent studies suggest that sirtuin 1 (SIRT1) has the potential to be a marker for undernutrition. This article summarizes available studies on the association of SIRT1 and undernutrition in older people. Possible associations between SIRT1 and the aging process, inflammation, and undernutrition in the elderly have been described. The literature suggests that low SIRT1 levels in the blood of older people may not be associated with physiological aging processes, but with an increased risk of severe undernutrition associated with inflammation and systemic metabolic changes.

The Foxo1-YAP-Notch1 axis reprograms STING-mediated innate immunity in NASH progression

Innate immune activation is critical for initiating hepatic inflammation during nonalcoholic steatohepatitis (NASH) progression. However, the mechanisms by which immunoregulatory molecules recognize lipogenic, fibrotic, and inflammatory signals remain unclear. Here, we show that high-fat diet (HFD)-induced oxidative stress activates Foxo1, YAP, and Notch1 signaling in hepatic macrophages. Macrophage Foxo1 deficiency (Foxo1M-KO) ameliorated hepatic inflammation, steatosis, and fibrosis, with reduced STING, TBK1, and NF-κB activation in HFD-challenged livers. However, Foxo1 and YAP double knockout (Foxo1/YAPM-DKO) or Foxo1 and Notch1 double knockout (Foxo1/Notch1M-DKO) promoted STING function and exacerbated HFD-induced liver injury. Interestingly, Foxo1M-KO strongly reduced TGF-β1 release from palmitic acid (PA)- and oleic acid (OA)-stimulated Kupffer cells and decreased Col1α1, CCL2, and Timp1 expression but increased MMP1 expression in primary hepatic stellate cells (HSCs) after coculture with Kupffer cells. Notably, PA and OA challenge in Kupffer cells augmented LIMD1 and LATS1 colocalization and interaction, which induced YAP nuclear translocation. Foxo1M-KO activated PGC-1α and increased nuclear YAP activity, modulating mitochondrial biogenesis. Using chromatin immunoprecipitation (ChIP) coupled with massively parallel sequencing (ChIP-Seq) and in situ RNA hybridization, we found that NICD colocalizes with YAP and targets Mb21d1 (cGAS), while YAP functions as a novel coactivator of the NICD, which is crucial for reprogramming STING function in NASH progression. These findings highlight the importance of the macrophage Foxo1-YAP-Notch1 axis as a key molecular regulator that controls lipid metabolism, inflammation, and innate immunity in NASH.

Cellular and Molecular Responses to Mitochondrial DNA Deletions in Kearns-Sayre Syndrome: Some Underlying Mechanisms

Kearns-Sayre syndrome (KSS) is a rare multisystem mitochondrial disorder. It is caused by mitochondrial DNA (mtDNA) rearrangements, mostly large-scale deletions of 1.1-10 kb. These deletions primarily affect energy supply through impaired oxidative phosphorylation and reduced ATP production. This impairment gives rise to dysfunction of several tissues, in particular those with high energy demand like brain and muscles. Over the past decades, changes in respiratory chain complexes and energy metabolism have been emphasized, whereas little attention has been paid to other reports on ROS overproduction, protein synthesis inhibition, myelin vacuolation, demyelination, autophagy, apoptosis, and involvement of lipid raft and oligodendrocytes in KSS. Therefore, this paper draws attention towards these relatively underemphasized findings that might further clarify the pathologic cascades following deletions in the mtDNA.

Mitochondrial dysfunction and its association with age-related disorders

Aging is a complex process that features a functional decline in many organelles. Various factors influence the aging process, such as chromosomal abnormalities, epigenetic changes, telomere shortening, oxidative stress, and mitochondrial dysfunction. Mitochondrial dysfunction significantly impacts aging because mitochondria regulate cellular energy, oxidative balance, and calcium levels. Mitochondrial integrity is maintained by mitophagy, which helps maintain cellular homeostasis, prevents ROS production, and protects against mtDNA damage. However, increased calcium uptake and oxidative stress can disrupt mitochondrial membrane potential and permeability, leading to the apoptotic cascade. This disruption causes increased production of free radicals, leading to oxidative modification and accumulation of mitochondrial DNA mutations, which contribute to cellular dysfunction and aging. Mitochondrial dysfunction, resulting from structural and functional changes, is linked to age-related degenerative diseases. This review focuses on mitochondrial dysfunction, its implications in aging and age-related disorders, and potential anti-aging strategies through targeting mitochondrial dysfunction.

Weak neuronal glycolysis sustains cognition and organismal fitness

The energy cost of neuronal activity is mainly sustained by glucose1,2. However, in an apparent paradox, neurons modestly metabolize glucose through glycolysis3-6, a circumstance that can be accounted for by the constant degradation of 6-phosphofructo-2-kinase-fructose-2,6-bisphosphatase-3 (PFKFB3)3,7,8, a key glycolysis-promoting enzyme. To evaluate the in vivo physiological importance of this hypoglycolytic metabolism, here we genetically engineered mice with their neurons transformed into active glycolytic cells through Pfkfb3 expression. In vivo molecular, biochemical and metabolic flux analyses of these neurons revealed an accumulation of anomalous mitochondria, complex I disassembly, bioenergetic deficiency and mitochondrial redox stress. Notably, glycolysis-mediated nicotinamide adenine dinucleotide (NAD+) reduction impaired sirtuin-dependent autophagy. Furthermore, these mice displayed cognitive decline and a metabolic syndrome that was mimicked by confining Pfkfb3 expression to hypothalamic neurons. Neuron-specific genetic ablation of mitochondrial redox stress or brain NAD+ restoration corrected these behavioural alterations. Thus, the weak glycolytic nature of neurons is required to sustain higher-order organismal functions.

Resilience to diabetic retinopathy

Chronic elevation of blood glucose at first causes relatively minor changes to the neural and vascular components of the retina. As the duration of hyperglycemia persists, the nature and extent of damage increases and becomes readily detectable. While this second, overt manifestation of diabetic retinopathy (DR) has been studied extensively, what prevents maximal damage from the very start of hyperglycemia remains largely unexplored. Recent studies indicate that diabetes (DM) engages mitochondria-based defense during the retinopathy-resistant phase, and thereby enables the retina to remain healthy in the face of hyperglycemia. Such resilience is transient, and its deterioration results in progressive accumulation of retinal damage. The concepts that co-emerge with these discoveries set the stage for novel intellectual and therapeutic opportunities within the DR field. Identification of biomarkers and mediators of protection from DM-mediated damage will enable development of resilience-based therapies that will indefinitely delay the onset of DR.

Unraveling the NRF2 confusion: Distinguishing nuclear respiratory factor 2 from nuclear erythroid factor 2

In recent years, the acronym NRF2 has garnered significant attention in scientific discourse. However, this attention has occasionally led to confusion due to the existence of two distinct proteins sharing the same acronym: Nuclear Respiratory Factor 2 (NRF2), also known as GA-binding protein transcription factor subunit alpha (GABPA), and Nuclear Factor Erythroid 2-related Factor 2 (NFE2L2 or NRF2). This confusion has been highlighted in various scientific forums, including PubPeer and anonymous reader comments, where the confusion between the two proteins has been expressed. In this article, we aim to elucidate the disparities between these two proteins. Both are transcription factors that play pivotal roles in cellular homeostasis and response to stress, with some overlapping functional aspects. Nuclear Factor Erythroid 2-related Factor 2 (NFE2L2) is a key regulator of the antioxidant response element (ARE) pathway. It functions by binding to antioxidant response elements in the promoters of target genes, thereby orchestrating the expression of various cytoprotective enzymes and proteins involved in detoxification, redox balance, and cellular defense against oxidative stress. Conversely, Nuclear Respiratory Factor 2 (GABPA) is primarily associated with the regulation of mitochondrial biogenesis, in relation to PGC1α, and maintaining cellular energy metabolism. It is important to recognize and differentiate between these two proteins to avoid misconceptions and misinterpretations in scientific literature and discussions. Our laboratories (Arubala P Reddy and P. Hemachandra Reddy) focued on Nuclear Respiratory Factor 2 (NRF2), but not on Nuclear Factor Erythroid 2-related Factor 2 (NFE2L2). We hope that the facts, figures, and discussions presented in this article will clarify the current controversy regarding the sizes, structural features, and functional aspects of these proteins.

Mitochondrial genetics through the lens of single-cell multi-omics

Mitochondria carry their own genetic information encoding for a subset of protein-coding genes and translational machinery essential for cellular respiration and metabolism. Despite its small size, the mitochondrial genome, its natural genetic variation and molecular phenotypes have been challenging to study using bulk sequencing approaches, due to its variation in cellular copy number, non-Mendelian modes of inheritance and propensity for mutations. Here we highlight emerging strategies designed to capture mitochondrial genetic variation across individual cells for lineage tracing and studying mitochondrial genetics in primary human cells and clinical specimens. We review recent advances surrounding single-cell mitochondrial genome sequencing and its integration with functional genomic readouts, including leveraging somatic mitochondrial DNA mutations as clonal markers that can resolve cellular population dynamics in complex human tissues. Finally, we discuss how single-cell whole mitochondrial genome sequencing approaches can be utilized to investigate mitochondrial genetics and its contribution to cellular heterogeneity and disease.

Differences in the Effect of Beta-Hydroxybutyrate on the Mitochondrial Biogenesis, Oxidative Stress and Inflammation Markers in Tissues from Young and Old Rats

One of the therapeutic approaches to age-related diseases is modulation of body cell metabolism through certain diets or their pharmacological mimetics. The ketogenic diet significantly affects cell energy metabolism and functioning of mitochondria, which has been actively studied in various age-related pathologies. Here, we investigated the effect of the ketogenic diet mimetic beta-hydroxybutyrate (BHB) on the expression of genes regulating mitochondrial biogenesis (Ppargc1a, Nrf1, Tfam), quality control (Sqstm1), functioning of the antioxidant system (Nfe2l2, Gpx1, Gpx3, Srxn1, Txnrd2, Slc6a9, Slc7a11), and inflammatory response (Il1b, Tnf, Ptgs2, Gfap) in the brain, lungs, heart, liver, kidneys, and muscles of young and old rats. We also analyzed mitochondrial DNA (mtDNA) copy number, accumulation of mtDNA damage, and levels of oxidative stress based on the concentration of reduced glutathione and thiobarbituric acid-reactive substances (TBARS). In some organs, aging disrupted mitochondrial biogenesis and functioning of cell antioxidant system, which was accompanied by the increased oxidative stress and inflammation. Administration of BHB for 2 weeks had different effects on the organs of young and old rats. In particular, BHB upregulated expression of genes coding for proteins associated with the mitochondrial biogenesis and antioxidant system, especially in the liver and muscles of young (but not old) rats. At the same time, BHB contributed to the reduction of TBARS in the kidneys of old rats. Therefore, our study has shown that administration of ketone bodies significantly affected gene expression in organs, especially in young rats, by promoting mitochondrial biogenesis, improving the functioning of the antioxidant defense system, and partially reducing the level of oxidative stress. However, these changes were much less pronounced in old animals.

Carfilzomib activates ER stress and JNK/p38 MAPK signaling to promote apoptosis in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is one of the most prevalent and deadly cancers in the world, which is frequently diagnosed at a late stage. HCC patients have a poor prognosis due to the lack of an efficacious therapeutic strategy. Approved drug repurposing is a way for accelerating drug discovery and can significantly reduce the cost of drug development. Carfilzomib (CFZ) is a second-generation proteasome inhibitor, which is highly efficacious against multiple myeloma and has been reported to possess potential antitumor activities against multiple cancers. However, the underlying mechanism of CFZ on HCC is still unclear. Here, we show that CFZ inhibits the proliferation of HCC cells through cell cycle arrest at the G2/M phase and suppresses the migration and invasion of HCC cells by inhibiting epithelial-mesenchymal transition. We also find that CFZ promotes reactive oxygen species production to induce endoplasmic reticulum (ER) stress and activate JNK/p38 MAPK signaling in HCC cells, thus inducing cell death in HCC cells. Moreover, CFZ significantly inhibits HCC cell growth in a xenograft mouse model. Collectively, our study elucidates that CFZ impairs mitochondrial function and activates ER stress and JNK/p38 MAPK signaling, thus inhibiting HCC cell and tumor growth. This indicates that CFZ has the potential as a therapeutic drug for HCC.

A Consolidated Understanding of the Contribution of Redox Dysregulation in the Development of Hearing Impairment

The etiology of hearing impairment is multifactorial, with contributions from both genetic and environmental factors. Although genetic studies have yielded valuable insights into the development and function of the auditory system, the contribution of gene products and their interaction with alternate environmental factors for the maintenance and development of auditory function requires further elaboration. In this review, we provide an overview of the current knowledge on the role of redox dysregulation as the converging factor between genetic and environmental factor-dependent development of hearing loss, with a focus on understanding the interaction of oxidative stress with the physical components of the peripheral auditory system in auditory disfunction. The potential involvement of molecular factors linked to auditory function in driving redox imbalance is an important promoter of the development of hearing loss over time.

Intermittent fasting along with hydroalcoholic extract of Centella-asiatica ameliorates sub-acute hypoxia-induced ischemic stroke in adult zebrafish

Reduced blood flow (hypoxia) to the brain is thought to be the main cause of strokes because it deprives the brain of oxygen and nutrients. An increasing amount of evidence indicates that the Centella-Asiatica (HA-CA) hydroalcoholic extract has a variety of pharmacological benefits, such as antioxidant activity, neuroprotection, anti-inflammatory qualities, and angiogenesis promotion. Intermittent fasting (IF) has neurological benefits such as anti-inflammatory properties, neuroprotective effects, and the ability to enhance neuroplasticity. The current study evaluates the combined effect of IF (for 1, 6, and 12 days) along with HA-CA (daily up to 12 days) in adult zebrafish subjected to hypoxia every 5 min for 12 days followed by behavioral (novel tank and open-field tank test), biochemical (SOD, GSH-Px, and LPO), inflammatory (IL-10, IL-1β, and TNF-α), mitochondrial enzyme activities (Complex-I, II, and IV), signaling molecules (AMPK, MAPK, GSK-3β, Nrf2), and imaging/staining (H&E, TTC, and TEM) analysis. Results show that sub-acute hypoxia promotes the behavioral alterations, and production of radical species and alters the oxidative stress status in brain tissues of zebrafish, along with mitochondrial dysfunction, neuroinflammation, and alteration of signaling molecules. Nevertheless, HA-CA along with IF significantly ameliorates these defects in adult zebrafish as compared to their effects alone. Further, imaging analysis significantly provided evidence of infarct damage along with neuronal and mitochondrial damage which was significantly ameliorated by IF and HA-CA. The use of IF and HA-CA has been proven to enhance the physiological effects of hypoxia in all dimensions.

High number of mitochondrial DNA alterations in postmortem brain tissue of patients with schizophrenia compared to healthy controls

Previous studies have shown mitochondrial dysfunction in schizophrenia (SZ) patients, which may be caused by mitochondrial DNA (mtDNA) alterations. However, there are few studies in SZ that have analyzed mtDNA in brain samples by next-generation sequencing (NGS). To address this gap, we used mtDNA-targeted NGS and qPCR to characterize mtDNA alterations in brain samples from patients with SZ (n = 40) and healthy controls (HC) (n = 40). 35 % of SZ patients showed mtDNA alterations, a significantly higher prevalence compared to 10 % of HC. Specifically, SZ patients had a significantly higher frequency of deletions (35 vs. 5 in HC), with a mean number of deletions of 3.8 in SZ vs. 1.0 in HC. Likely pathogenic missense variants were also significantly more frequent in patients with SZ than in HC (10 vs. three HC), encompassing 14 variants in patients and three in HC. The pathogenic tRNA variant m.3243A>G was identified in one SZ patient with a high heteroplasmy level of 32.2 %. While no significant differences in mtDNA copy number (mtDNA-CN) were observed between SZ and HC, antipsychotic users had significantly higher mtDNA-CN than non-users. These findings suggest a potential role for mtDNA alterations in the pathophysiology of SZ that require further validation and functional studies.

Neurodegenerative Etiology of Aromatic L-Amino Acid Decarboxylase Deficiency: a Novel Concept for Expanding Treatment Strategies

Aromatic l-amino acid decarboxylase deficiency (AADC-DY) is caused by one or more mutations in the DDC gene, resulting in the deficit in catecholamines and serotonin neurotransmitters. The disease has limited therapeutic options with relatively poor clinical outcomes. Accumulated evidence suggests the involvement of neurodegenerative mechanisms in the etiology of AADC-DY. In the absence of neurotransmitters' neuroprotective effects, the accumulation and the chronic presence of several neurotoxic metabolites including 4-dihydroxy-L-phenylalanine, 3-methyldopa, and homocysteine, in the brain of subjects with AADC-DY, promote oxidative stress and reduce the cellular antioxidant and methylation capacities, leading to glial activation and mitochondrial dysfunction, culminating to neuronal injury and death. These pathophysiological processes have the potential to hinder the clinical efficacy of treatments aimed at increasing neurotransmitters' synthesis and or function. This review describes in detail the mechanisms involved in AADC-DY neurodegenerative etiology, highlighting the close similarities with those involved in other neurodegenerative diseases. We then offer novel strategies for the treatment of the disease with the objective to either reduce the level of the metabolites or counteract their prooxidant and neurotoxic effects. These treatment modalities used singly or in combination, early in the course of the disease, will minimize neuronal injury, preserving the functional integrity of neurons, hence improving the clinical outcomes of both conventional and unconventional interventions in AADC-DY. These modalities may not be limited to AADC-DY but also to other metabolic disorders where a specific mutation leads to the accumulation of prooxidant and neurotoxic metabolites.

Mitochondrial DNA Leakage and cGas/STING Pathway in Microglia: Crosstalk Between Neuroinflammation and Neurodegeneration

Neurodegenerative diseases, characterized by abnormal deposition of misfolded proteins, often present with progressive loss of neurons. Chronic neuroinflammation is a striking hallmark of neurodegeneration. Microglia, as the primary immune cells in the brain, is the main type of cells that participate in the formation of inflammatory microenvironment. Cytoplasmic free mitochondrial DNA (mtDNA), a common component of damage-associated molecular patterns (DAMPs), can activate the cGas/stimulator of interferon genes (STING) signalling, which subsequently produces type I interferon and proinflammatory cytokines. There are various sources of free mtDNA in microglial cytoplasm, but mitochondrial oxidative stress accumulation plays the vital role. The upregulation of cGas/STING pathway in microglia contributes to the abnormal and persistent microglial activation, accompanied by excessive secretion of neurotoxic inflammatory mediators such as interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), which exacerbates the damage of neurons and promotes the development of neurodegeneration. Currently, novel therapeutic approaches need to be found to delay the progression of neurodegenerative disorders, and regulation of the cGas/STING signaling in microglia may be a potential target.

Neuroglia targeting nano-therapeutic approaches to rescue aging and neurodegenerating brain

Despite intense efforts at the bench, the development of successful brain-targeting therapeutics to relieve malicious neural diseases remains primitive. The brain, being a beautifully intricate organ, consists of heterogeneous arrays of neuronal and glial cells. Primarily acting as the support system for neuronal functioning and maturation, glial cells have been observed to be engaged more apparently in the progression and worsening of various neural pathologies. The diseased state is often related to metabolic alterations in glial cells, thereby modulating their physiological homeostasis in conjunction with neuronal dysfunction. A plethora of data indicates the effect of oxidative stress, protein aggregation, and DNA damage in neuroglia impairments. Still, a deeper insight is needed to gain a conflict-free understanding in this arena. As a consequence, glial cells hold the potential to be identified as promising targets for novel therapeutic approaches aimed at brain protection. In this review, we describe the recent strides taken in the direction of understanding the impact of oxidative stress, protein aggregation, and DNA damage on neuroglia impairment and neuroglia-directed nanotherapeutic approaches to mitigate the burden of various neural disorders.

DNA Damage and Parkinson's Disease

The etiology underlying most sporadic Parkinson's' disease (PD) cases is unknown. Environmental exposures have been suggested as putative causes of the disease. In cell models and in animal studies, certain chemicals can destroy dopaminergic neurons. However, the mechanisms of how these chemicals cause the death of neurons is not understood. Several of these agents are mitochondrial toxins that inhibit the mitochondrial complex I of the electron transport chain. Familial PD genes also encode proteins with important functions in mitochondria. Mitochondrial dysfunction of the respiratory chain, in combination with the presence of redox active dopamine molecules in these cells, will lead to the accumulation of reactive oxygen species (ROS) in dopaminergic neurons. Here, I propose a mechanism regarding how ROS may lead to cell killing with a specificity for neurons. One rarely considered hypothesis is that ROS produced by defective mitochondria will lead to the formation of oxidative DNA damage in nuclear DNA. Many genes that encode proteins with neuron-specific functions are extraordinary long, ranging in size from several hundred kilobases to well over a megabase. It is predictable that such long genes will contain large numbers of damaged DNA bases, for example in the form of 8-oxoguanine (8-oxoG), which is a major DNA damage type produced by ROS. These DNA lesions will slow down or stall the progression of RNA polymerase II, which is a term referred to as transcription stress. Furthermore, ROS-induced DNA damage may cause mutations, even in postmitotic cells such as neurons. I propose that the impaired transcription and mutagenesis of long, neuron-specific genes will lead to a loss of neuronal integrity, eventually leading to the death of these cells during a human lifetime.

The role of DNA damage in neural stem cells ageing

Neural stem cells (NSCs) are pluripotent stem cells with the potential to differentiate into a variety of nerve cells. NSCs are susceptible to both intracellular and extracellular insults, thus causing DNA damage. Extracellular insults include ultraviolet, ionizing radiation, base analogs, modifiers, alkyl agents and others, while intracellular factors include Reactive oxygen species (ROS) radicals produced by mitochondria, mismatches that occur during DNA replication, deamination of bases, loss of bases, and more. When encountered with DNA damage, cells typically employ three coping strategies: DNA repair, damage tolerance, and apoptosis. NSCs, like many other stem cells, have the ability to divide, differentiate, and repair DNA damage to prevent mutations from being passed down to the next generation. However, when DNA damage accumulates over time, it will lead to a series of alterations in the metabolism of cells, which will cause cellular ageing. The ageing and exhaustion of neural stem cell will have serious effects on the body, such as neurodegenerative diseases. The purpose of this review is to examine the processes by which DNA damage leads to NSCs ageing and the mechanisms of DNA repair in NSCs.

Fragile X Messenger Ribonucleoprotein Protein and Its Multifunctionality: From Cytosol to Nucleolus and Back

Silencing of the fragile X messenger ribonucleoprotein 1 (FMR1) gene and a consequent lack of FMR protein (FMRP) synthesis are associated with fragile X syndrome, one of the most common inherited intellectual disabilities. FMRP is a multifunctional protein that is involved in many cellular functions in almost all subcellular compartments under both normal and cellular stress conditions in neuronal and non-neuronal cell types. This is achieved through its trafficking signals, nuclear localization signal (NLS), nuclear export signal (NES), and nucleolar localization signal (NoLS), as well as its RNA and protein binding domains, and it is modulated by various post-translational modifications such as phosphorylation, ubiquitination, sumoylation, and methylation. This review summarizes the recent advances in understanding the interaction networks of FMRP with a special focus on FMRP stress-related functions, including stress granule formation, mitochondrion and endoplasmic reticulum plasticity, ribosome biogenesis, cell cycle control, and DNA damage response.

Chronic hypoxia remodels the tumor microenvironment to support glioma stem cell growth

Cerebral organoids co-cultured with patient derived glioma stem cells (GLICOs) are an experimentally tractable research tool useful for investigating the role of the human brain tumor microenvironment in glioblastoma. Here we describe long-term GLICOs, a novel model in which COs are grown from embryonic stem cell cultures containing low levels of GSCs and tumor development is monitored over extended durations (ltGLICOs). Single-cell profiling of ltGLICOs revealed an unexpectedly long latency period prior to GSC expansion, and that normal organoid development was unimpaired by the presence of low numbers of GSCs. However, as organoids age they experience chronic hypoxia and oxidative stress which remodels the tumor microenvironment to promote GSC expansion. Receptor-ligand modelling identified astrocytes, which secreted various pro-tumorigenic ligands including FGF1, as the primary cell type for GSC crosstalk and single-cell multi-omic analysis revealed these astrocytes were under the control of ischemic regulatory networks. Functional validation confirmed hypoxia as a driver of pro-tumorigenic astrocytic ligand secretion and that GSC expansion was accelerated by pharmacological induction of oxidative stress. When controlled for genotype, the close association between glioma aggressiveness and patient age has very few proposed biological explanations. Our findings indicate that age-associated increases in cerebral vascular insufficiency and associated regional chronic cerebral hypoxia may contribute to this phenomenon.

Mitochondrial-targeting and NIR-responsive Mn3O4@PDA@Pd-SS31 nanozymes reduce oxidative stress and reverse mitochondrial dysfunction to alleviate osteoarthritis

Mitochondrial reactive oxygen species (mROS) play a crucial role in the process of osteoarthritis (OA), which may be a promising target for therapy of OA. In this study, novel mitochondrial-targeting and SOD-mimic Mn3O4@PDA@Pd-SS31 nanozymes with near-infrared (NIR) responsiveness and synergistic cascade to scavenge mROS were designed for the therapy of OA. Results showed that the nanozymes accelerated the release of Pd and Mn3O4 under NIR irradiation, exhibiting enhanced activities of SOD and CAT mimic enzymes with reversed mitochondrial dysfunction and promoted mitophagy to effectively scavenge mROS from chondrocytes, modulate the microenvironment of oxidative stress, and eventually inhibit the inflammatory response. Nanozymes were excreted in vivo through intestinal metabolic pathway and had good biocompatibility, effectively reducing the inflammatory response and relieving articular cartilage degeneration in OA joints, with a reduction of 93.7 % and 93.8 % in OARSCI scores for 4 and 8 weeks respectively. Thus, this study demonstrated that the mitochondria targeting and NIR responsive Mn3O4@PDA@Pd-SS31 nanozymes could efficiently scavenge mROS, repair damaged mitochondrial function and promote cartilage regeneration, which are promising for the treatment of OA in clinical applications.

Structure characterization of polysaccharides from Cistanche deserticola and their neuroprotective effects against oxidative stress in slow transit constipation mice

Oxidative stress-induced enteric neuropathy is an important factor in slow transit constipation (STC). Cistanche deserticola crude polysaccharides (CDCP) are natural antioxidants with various biological activities. We prepared CDCP through water-extract and alcohol-precipitation methods. The structural characteristics of CDCP were analyzed by infrared spectroscopy and methylation analysis. The results showed that CDCP was primarily composed of (1 → 4)-linked glucans with minor amounts of pectic polysaccharides. Different doses of CDCP (100, 200, and 400 mg/kg) were administered to loperamide-induced STC mice to explore the therapeutic effects of CDCP. Compared with the untreated group, CDCP treatment significantly improved constipation symptoms, relevant gut-regulating peptides levels, colonic pathological damage, and colonic myenteric nerons injury. CDCP enhanced the antioxidant capacity by decreasing Malondialdehyde (MDA) content, increasing Superoxide Dismutase (SOD) activity and Reduced Glutathione (GSH) content. CDCP significantly reduced oxidative stress-induced injury by preserving mitochondrial function in the colonic myenteric plexus. Furthermore, the neuroprotective effects of CDCP might be associated with the Nrf2/Keap1 pathway. Thus, our findings first revealed the potential of CDCP to protect the colonic myenteric plexus against oxidative stress-induced damage in STC, establishing CDCP as promising candidates for natural medicine in the clinical management of STC.

Probiotic Lactiplantibacillus plantarum KU210152 and its fermented soy milk attenuates oxidative stress in neuroblastoma cells

We evaluated the probiotic properties and neuroprotective effects of Lactiplantibacillus plantarum KU210152 and its application in soy milk. L. plantarum KU210152 exhibited high tolerance to artificial gastrointestinal conditions, high adhesion to intestinal cells (HT-29), and safe enzyme production. Conditioned medium acquired from HT-29 cells treated with heat-killed lactic acid bacteria (LAB-CM) was used to evaluate the neuroprotective effects. The CM exhibited neuroprotective effects via cell viability assay, morphological observations, and suppression of ROS production. Heat-killed L. plantarum KU210152 increased brain-derived neurotrophic factor (BDNF) and tyrosine hydroxylase (TH) expression in HT-29 cells. In SH-SY5Y cells, pretreatment with L. plantarum KU210152 CM decreased Bax/Bcl-2 ratio and upregulated BDNF and TH expression. The CM inhibited caspase-9 and caspase-3 activities. The neuroprotective effects of L. plantarum KU210152 were also confirmed in fermented soy milk. Therefore, both L. plantarum KU210152 and the fermented soy milk can be used as functional ingredients with neuroprotective effects against oxidative stress.