Structure and mechanism of mitochondrial electron transport chain

Iron chelators as mitophagy agents: Potential and limitations

Mitochondrial autophagy (mitophagy) is very important process for the maintenance of cellular homeostasis, functionality and survival. Its dysregulation is associated with high risk and progression numerous serious diseases (e.g., oncological, neurodegenerative and cardiovascular ones). Therefore, targeting mitophagy mechanisms is very hot topic in the biological and medicinal research. The interrelationships between the regulation of mitophagy and iron homeostasis are now becoming apparent. In short, mitochondria are central point for the regulation of iron homeostasis, but change in intracellular cheatable iron level can induce/repress mitophagy. In this review, relationships between iron homeostasis and mitophagy are thoroughly discussed and described. Also, therapeutic applicability of mitophagy chelators in the context of individual diseases is comprehensively and critically evaluated.

Copper-loaded Milk-Protein Derived Microgel Preserves Cardiac Metabolic Homeostasis After Myocardial Infarction

Myocardial Infarction (MI) is a leading cause of death worldwide. Metabolic modulation is a promising therapeutic approach to prevent adverse remodeling after MI. However, whether material-derived cues can treat MI through metabolic regulation is mainly unexplored. Herein, a Cu2+ loaded casein microgel (CuCMG) aiming to rescue the pathological intramyocardial metabolism for MI amelioration is developed. Cu2+ is an important ion factor involved in metabolic pathways, and intracardiac copper drain is observed after MI. It is thus speculated that intramyocardial supplementation of Cu2+ can rescue myocardial metabolism. Casein, a milk-derived protein, is screened out as Cu2+ carrier through molecular-docking based on Cu2+ loading capacity and accessibility. CuCMGs notably attenuate MI-induced cardiac dysfunction and maladaptive remodeling, accompanied by increased angiogenesis. The results from unbiased transcriptome profiling and oxidative phosphorylation analyses support the hypothesis that CuCMG prominently rescued the metabolic homeostasis of myocardium after MI. These findings enhance the understanding of the design and application of metabolic-modulating biomaterials for ischemic cardiomyopathy therapy.

Pathophysiological Mechanisms of Psychosis-Induced Atrial Fibrillation: The Links between Mental Disorder and Arrhythmia

Atrial fibrillation (AF) is a common phenomenon of sustained arrhythmia leading to heart failure or stroke. Patients with mental disorders (MD), particularly schizophrenia and bipolar disorder, are at a high risk of AF triggered by the dysregulation of the autonomic nervous system, atrial stretch, oxidative stress, inflammation, and electrical or structural remodeling. Moreover, pathophysiological mechanisms underlying MD may also contribute to the genesis of AF. An overactivated hypothalamic-pituitary-adrenal axis, aberrant renin-angiotensin-aldosterone system, abnormal serotonin signaling, disturbed sleep, and genetic/epigenetic factors can adversely alter atrial electrophysiology and structural substrates, leading to the development of AF. In this review, we provide an update of our collective knowledge of the pathophysiological and molecular mechanisms that link MD and AF. Targeting the pathogenic mechanisms of MD-specific AF may facilitate the development of therapeutics that mitigate AF and cardiovascular mortality in this patient population.

Mitochondria: a breakthrough in combating rheumatoid arthritis

As a chronic autoimmune disease with complex aetiology, rheumatoid arthritis (RA) has been demonstrated to be associated with mitochondrial dysfunction since mitochondrial dysfunction can affect the survival, activation, and differentiation of immune and non-immune cells involved in the pathogenesis of RA. Nevertheless, the mechanism behind mitochondrial dysfunction in RA remains uncertain. Accordingly, this review addresses the possible role and mechanisms of mitochondrial dysfunction in RA and discusses the potential and challenges of mitochondria as a potential therapeutic strategy for RA, thereby providing a breakthrough point in the prevention and treatment of RA.

Linking mitochondrial dysfunction, neurotransmitter, neural network abnormalities and mania: Elucidating neurobiological mechanisms of the therapeutic effect of the ketogenic diet in Bipolar Disorder

There is growing interest in the ketogenic diet as a treatment for Bipolar Disorder (BD), with promising anecdotal and small case study reports of efficacy. Yet, the neurobiological mechanisms by which diet-induced ketosis might ameliorate BD symptoms remain to be determined, particularly in manic and hypomanic states - defining features of BD. Identifying these mechanisms will therefore provide new markers to guide personalized interventions and provide targets for novel treatment developments for individuals with BD. In this critical review, we describe recent findings highlighting two types of neurobiological abnormalities in BD: 1) mitochondrial dysfunction; and 2) neurotransmitter and neural network functional abnormalities. We will consequently link these abnormalities lead to mania/hypomania and depression in BD and then describe the biological underpinnings by which the ketogenic diet might have a beneficial effect in individuals with BD. We end the review by describing future approaches that can be employed to elucidate the neurobiology underlying the therapeutic effect of the ketogenic diet in BD. In so doing, this may provide marker predictors to identify individuals who will respond well to the ketogenic diet, as well as offer neural targets for novel treatment developments for BD.

BDNF-TrkB Signaling in Mitochondria: Implications for Neurodegenerative Diseases

Brain-derived neurotrophic factor (BDNF) plays a pivotal role in neuronal development, synaptic plasticity, and overall neuronal health by binding to its receptor, tyrosine receptor kinase B (TrkB). This review delves into the intricate mechanisms through which BDNF-TrkB signaling influences mitochondrial function and potentially influences pathology in neurodegenerative diseases. This review highlights the BDNF-TrkB signaling pathway which regulates mitochondrial bioenergetics, biogenesis, and dynamics, mitochondrial processes vital for synaptic transmission and plasticity. Furthermore, we explore how the BDNF-TrkB-PKA signaling in the cytosol and in mitochondria affects mitochondrial transport and distribution and mitochondrial content, which is crucial for supporting the energy demands of synapses. The dysregulation of this signaling pathway is linked to various neurodegenerative diseases, including Alzheimer's and Parkinson's disease, which are characterized by mitochondrial dysfunction and reduced BDNF expression. By examining seminal studies that have characterized this signaling pathway in health and disease, the present review underscores the potential of enhancing BDNF-TrkB signaling to mitigate mitochondrial dysfunction in neurodegenerative diseases, offering insights into therapeutic strategies to enhance neuronal resilience and function.

Crosstalk between gut-brain axis: unveiling the mysteries of gut ROS in progression of Parkinson's disease

"Path to a good mood lies through the gut." This statement seems to imply that it has long been believed that the gut is connected with the brain. Research has shown that eating food activates the reward system and releases dopamine (DA), establishing a link between the peripheral and central nervous system. At the same time, researchers also trust that the gut is involved in the onset of many diseases, including Parkinson's disease (PD), in which gastrointestinal dysfunction is considered a prevalent symptom. Reports suggest that PD starts from the gut and reaches the brain via the vagus nerve. Recent studies have revealed an intriguing interaction between the gut and brain, which links gut dysbiosis to the etiology of PD. This review aims to explore the mechanistic pathway how reactive oxygen species (ROS) generation in the gut affects the makeup and operation of the dopamine circuitry in the brain. Our primary concern is ROS generation in the gut, which disrupts the gut microbiome (GM), causing α-synuclein accumulation and inflammation. This trio contributes to the loss of DA neurons in the brain, resulting in PD development. This review also compiles pre-clinical and clinical studies on antioxidants, demonstrating that antioxidants reduce ROS and increase DA levels. Collectively, the study highlights the necessity of comprehending the gut-brain axis for unraveling the riddles of PD pathogenesis and considering new therapeutic approaches.

Using our understanding of interactions between helminth metabolism and host immunity to target worm survival

Helminths can adapt to environmental conditions in the host, utilising anaerobic processes like fermentation and malate dismutation to produce energy from carbohydrate. Although targeting carbohydrate metabolism is an established therapeutic strategy to combat helminth infection, questions remain over the metabolic pathways they employ as adults to survive and evade host immunity. Helminths also use amino acid, polyunsaturated fatty acid (PUFA), and cholesterol metabolism, a possible strategy favouring the production of immunomodulatory compounds that may influence survival in the host. Here, we discuss the significance of these differing metabolic pathways and whether targeting of helminth metabolic pathways may allow for the development of novel anthelmintics.

Pharmacological mechanism of natural antidepressants: The role of mitochondrial quality control

BACKGROUND

Depression is a mental illness characterized by persistent sadness and a reduced capacity for pleasure. In clinical practice, SSRIs and other medications are commonly used for therapy, despite their various side effects. Natural products present distinct advantages, including synergistic interactions among multiple components and targeting multiple pathways, suggesting their tremendous potential in depression treatment. Imbalance in mitochondrial quality control (MQC) plays a significant role in the pathology of depression, emphasizing the importance of regulating MQC as a potential intervention strategy in addressing the onset and progression of depression. However, the role and mechanism through which natural products regulate MQC in depression treatments still need to be comprehensively elucidated, particularly in clinical and preclinical settings.

PURPOSE

This review was aimed to summarize the findings of recent studies and outline the pharmacological mechanisms by which natural products modulate MQC to exert antidepressant effects. Additionally, it evaluated current research limitations and proposed new strategies for future preclinical and clinical applications in the depression domain.

METHODS

To study the main pharmacological mechanisms underlying the regulation of MQC by natural products in the treatment of depression, we conducted a thorough search across databases such as PubMed, Web of Science, and ScienceDirect databases to classify and summarize the relationship between MQC and depression, as well as the regulatory mechanisms of natural products.

RESULTS

Numerous studies have shown that irregularities in the MQC system play an important role in the pathology of depression, and the regulation of the MQC system is involved in antidepressant treatments. Natural products mainly regulate the MQC system to induce antidepressant effects by alleviating oxidative stress, balancing ATP levels, promoting mitophagy, maintaining calcium homeostasis, optimizing mitochondrial dynamics, regulating mitochondrial membrane potential, and enhancing mitochondrial biogenesis.

CONCLUSIONS

We comprehensively summarized the regulation of natural products on the MQC system in antidepressants, providing a unique perspective for the application of natural products within antidepressant therapy. However, extensive efforts are imperative in clinical and preclinical investigations to delve deeper into the mechanisms underlying how antidepressant medications impact MQC, which is crucial for the development of effective antidepressant treatments.

Roles of alcohol dehydrogenase 1 in the biological activities of Candida albicans

Candida albicans stands as the foremost prevalent human commensal pathogen and a significant contributor to nosocomial fungal infections. In the metabolism of C. albicans, alcohol dehydrogenase 1 (Adh1) is one of the important enzymes that converts acetaldehyde produced by pyruvate decarboxylation into ethanol at the end of glycolysis. Leveraging the foundational processes of alcoholic fermentation, Adh1 plays an active role in multiple biological phenomena, including biofilm formation, interactions between different species, the development of drug resistance, and the potential initiation of gastrointestinal cancer. Additionally, Adh1 within C. albicans has demonstrated associations with regulating the cell cycle, stress responses, and various intracellular states. Furthermore, Adh1 is extracellularly localized on the cell wall surface, where it plays roles in processes such as tissue invasion and host immune responses. Drawing from an analysis of ADH1 gene structure, expression patterns, and fundamental functions, this review elucidates the intricate connections between Adh1 and various biological processes within C. albicans, underscoring its potential implications for the prevention, diagnosis, and treatment of candidiasis.

Hybrid non-animal modeling: A mechanistic approach to predict chemical hepatotoxicity

Developing mechanistic non-animal testing methods based on the adverse outcome pathway (AOP) framework must incorporate molecular and cellular key events associated with target toxicity. Using data from an in vitro assay and chemical structures, we aimed to create a hybrid model to predict hepatotoxicants. We first curated a reference dataset of 869 compounds for hepatotoxicity modeling. Then, we profiled them against PubChem for existing in vitro toxicity data. Of the 2560 resulting assays, we selected the mitochondrial membrane potential (MMP) assay, a high-throughput screening (HTS) tool that can test chemical disruptors for mitochondrial function. Machine learning was applied to develop quantitative structure-activity relationship (QSAR) models with 2536 compounds tested in the MMP assay for screening new compounds. The MMP assay results, including QSAR model outputs, yielded hepatotoxicity predictions for reference set compounds with a Correct Classification Ratio (CCR) of 0.59. The predictivity improved by including 37 structural alerts (CCR = 0.8). We validated our model by testing 37 reference set compounds in human HepG2 hepatoma cells, and reliably predicting them for hepatotoxicity (CCR = 0.79). This study introduces a novel AOP modeling strategy that combines public HTS data, computational modeling, and experimental testing to predict chemical hepatotoxicity.

Neutralization of CX3CL1 Attenuates TGF-β-Induced Fibroblast Differentiation Through NF-κB Activation and Mitochondrial Dysfunction in Airway Fibrosis

BACKGROUND

Severe asthma, characterized by inflammation and airway remodeling, involves fibroblast differentiation into myofibroblasts expressing α-SMA. This process leads to the production of fibronectin and connective tissue growth factor (CTGF), driven by factors such as transforming growth factor (TGF)-β. Furthermore, the persistent presence of myofibroblasts is associated with resistance to apoptosis and mitochondrial dysfunction. The chemokine (C-X3-C motif) ligand 1 (CX3CL1) plays a role in tissue fibrosis. However, it is currently unknown whether neutralization of CX3CL1 decreases TGF-β-induced fibroblast differentiation and mitochondrial dysfunction in normal human lung fibroblasts (NHLFs).

METHODS

CX3CL1/C-X3-C motif chemokine receptor 1 (CX3CR1), CX3CL1 was analyzed by immunofluorescence (IF) or immunohistochemical (IHC) staining of ovalbumin-challenged mice. CX3CL1 release was detected by ELISA. TGF-β-induced CTGF, fibronectin, and α-SMA expression were evaluated in NHLFs following neutralization of CX3CL1 (TP213) treatment for the indicated times by Western blotting or IF staining. Mitochondrion function was detected by a JC-1 assay and seahorse assay. Cell apoptosis was observed by a terminal uridine nick-end labeling (TUNEL) assay.

RESULTS

An increase in CX3CL1 expression was observed in lung tissues from mice with ovalbumin-induced asthma by IF staining. CX3CR1 was increased in the subepithelial layer of the airway by IHC staining. Moreover, CX3CR1 small interfering (si)RNA downregulated TGF-β-induced CTGF and fibronectin expression in NHLFs. CX3CL1 induced CTGF and fibronectin expression in NHLFs. TGF-β-induced CX3CL1 secretion from NHLFs. Furthermore, TP213 decreased TGF-β-induced CTGF, fibronectin, and α-SMA expression in NHLFs. Mitochondrion-related differentially expressed genes (DEGs) were examined after CX3CL1 neutralization in TGF-β-treated NHLFs. TP213 alleviated TGF-β-induced mitochondrial dysfunction and apoptosis resistance in NHLFs. CX3CL1 induced p65, IκBα, and IKKα phosphorylation in a time-dependent manner. Furthermore, CX3CL1-induced fibronectin expression and JC-1 monomer were decreased by p65 siRNA. TP213 reduced TGF-β-induced p65 and α-SMA expression in NHLFs.

CONCLUSIONS

These findings suggest that neutralizing CX3CL1 attenuates lung fibroblast activation and mitochondrial dysfunction. Understanding the impacts of CX3CL1 neutralization on fibroblast mitochondrial function could contribute to the development of therapeutic strategies for managing airway remodeling in severe asthma.

Connection Between HIV and Mitochondria in Cardiovascular Disease and Implications for Treatments

HIV infection and antiretroviral therapy alter mitochondrial function, which can progressively lead to mitochondrial damage and accelerated aging. The interaction between persistent HIV reservoirs and mitochondria may provide insight into the relatively high rates of cardiovascular disease and mortality in persons living with HIV. In this review, we explore the intricate relationship between HIV and mitochondrial function, highlighting the potential for novel therapeutic strategies in the context of cardiovascular diseases. We reflect on mitochondrial dynamics, mitochondrial DNA, and mitochondrial antiviral signaling protein in the context of HIV. Furthermore, we summarize how toxicities related to early antiretroviral therapy and current highly active antiretroviral therapy can contribute to mitochondrial dysregulation, chronic inflammation, and poor clinical outcomes. There is a need to understand the mechanisms and develop new targeted therapies. We further consider current and potential future therapies for HIV and their interplay with mitochondria. We reflect on the next-generation antiretroviral therapies and HIV cure due to the direct and indirect effects of HIV persistence, associated comorbidities, coinfections, and the advancement of interdisciplinary research fields. This includes exploring novel and creative approaches to target mitochondria for therapeutic intervention.

Mitochondrial dysfunction: A promising therapeutic target for liver diseases

The liver is an important metabolic and detoxification organ and hence demands a large amount of energy, which is mainly produced by the mitochondria. Liver tissues of patients with alcohol-related or non-alcohol-related liver diseases contain ultrastructural mitochondrial lesions, mitochondrial DNA damage, disturbed mitochondrial dynamics, and compromised ATP production. Overproduction of mitochondrial reactive oxygen species induces oxidative damage to mitochondrial proteins and mitochondrial DNA, decreases mitochondrial membrane potential, triggers hepatocyte inflammation, and promotes programmed cell death, all of which impair liver function. Mitochondrial DNA may be a potential novel non-invasive biomarker of the risk of progression to liver cirrhosis and hepatocellular carcinoma in patients infected with the hepatitis B virus. We herein present a review of the mechanisms of mitochondrial dysfunction in the development of acute liver injury and chronic liver diseases, such as hepatocellular carcinoma, viral hepatitis, drug-induced liver injury, alcoholic liver disease, and non-alcoholic fatty liver disease. This review also discusses mitochondrion-centric therapies for treating liver diseases.

Up-regulation of MIC19 promotes growth and metastasis of hepatocellular carcinoma by activating ROS/NF-κB signaling

BACKGROUND

Mitochondrial malfunction has been well-recognized as a critical step in the pathogenesis of many types of diseases, including cancer. MIC19 is a core a subunit of the MICOS complex that plays a critical role in maintaining the normal function of mitochondria. However, the biological functions of MIC19 in human hepatocellular carcinoma (HCC) remain unclear.

METHODS

The expression level of MIC19 in HCC was evaluated by bioinformatics analysis, quantitative real-time PCR and immunohistochemistry staining assays. Cell growth and metastasis experiments were used to assess the biological functions of MIC19 in HCC cells.

FINDINGS

MIC19 expression was frequently upregulated in both human HCC specimens and cell lines, and its upregulation is closely associated with patients' survival. Results from loss-of-function and gain-of-function experiments demonstrated that knockdown of MIC19 significantly attenuated, while overexpression of MIC19 enhanced, the proliferation, colony formation, migration and invasion abilities of HCC cells. Mechanistically, we found that MIC19 has no effect on mitochondrial energy production, while activated ROS/NF-κB signaling, which was required for MIC19-promoted HCC growth and metastasis.

INTERPRETATION

Our findings suggest that MIC19 play a critical oncogenic role in HCC, implying that MIC19 may serve as a potential therapeutic target in the treatment of HCC.

[Effects of Oxidative Stress on Mitochondrial Functions and Intervertebral Disc Cells]

Intervertebral disc degeneration is widely recognized as one of the main causes of lower back pain. Intervertebral disc cells are the primary cellular components of the discs, responsible for synthesizing and secreting collagen and proteoglycans to maintain the structural and functional stability of the discs. Additionally, intervertebral disc cells are involved in maintaining the nutritional and metabolic balance, as well as exerting antioxidant and anti-inflammatory effects within the intervertebral discs. Consequently, intervertebral disc cells play a crucial role in the process of disc degeneration. When these cells are exposed to oxidative stress, mitochondria can be damaged, which may disrupt normal cellular function and accelerate degenerative changes. Mitochondria serve as the powerhouse of cells, being the primary energy-producing organelles that control a number of vital processes, such as cell death. On the other hand, mitochondrial dysfunction may be associated with various degenerative pathophysiological conditions. Moreover, mitochondria are the key site for oxidation-reduction reactions. Excessive oxidative stress and reactive oxygen species can negatively impact on mitochondrial function, potentially leading to mitochondrial damage and impaired functionality. These factors, in turn, triggers inflammatory responses, mitochondrial DNA damage, and cell apoptosis, playing a significant role in the pathological processes of intervertebral disc cell degeneration. This review is focused on exploring the impact of oxidative stress and reactive oxygen species on mitochondria and the crucial roles played by oxidative stress and reactive oxygen species in the pathological processes of intervertebral disc cells. In addition, we discussed current cutting-edge treatments and introduced the use of mitochondrial antioxidants and protectants as a potential method to slow down oxidative stress in the treatment of disc degeneration.

Novel sulfonamide-indolinone hybrids targeting mitochondrial respiration of breast cancer cells

Breast cancer (BC) still poses a threat worldwide which demands continuous efforts to present safer and efficacious treatment options via targeted therapy. Beside kinases' aberrations as Aurora B kinase which controls cell division, BC adopts distinct metabolic profiles to meet its high energy demands. Accordingly, targeting both aurora B kinase and/or metabolic vulnerability presents a promising approach to tackle BC. Based on a previously reported indolinone-based Aurora B kinase inhibitor (III), and guided by structural modification and SAR investigation, we initially synthesized 11 sulfonamide-indolinone hybrids (5a-k), which showed differential antiproliferative activities against the NCI-60 cell line panel with BC cells displaying preferential sensitivity. Nonetheless, modest activity against Aurora B kinase (18-49% inhibition) was noted at 100 nM. Screening of a representative derivative (5d) against 17 kinases, which are overexpressed in BC, failed to show significant activity at 1 μM concentration, suggesting that kinase inhibitory activity only played a partial role in targeting BC. Bioinformatic analyses of genome-wide transcriptomics (RNA-sequencing), metabolomics, and CRISPR loss-of-function screens datasets suggested that indolinone-completely responsive BC cell lines (MCF7, MDA-MB-468, and T-47D) were more dependent on mitochondrial oxidative phosphorylation (OXPHOS) compared to partially responsive BC cell lines (MDA-MB-231, BT-549, and HS 578 T). An optimized derivative, TC11, obtained by molecular hybridization of 5d with sunitinib polar tail, manifested superior antiproliferative activity and was used for further investigations. Indeed, TC11 significantly reduced/impaired the mitochondrial respiration, as well as mitochondria-dependent ROS production of MCF7 cells. Furthermore, TC11 induced G0/G1 cell cycle arrest and apoptosis of MCF7 BC cells. Notably, anticancer doses of TC11 did not elicit cytotoxic effects on normal cardiomyoblasts and hepatocytes. Altogether, these findings emphasize the therapeutic potential of targeting the metabolic vulnerability of OXPHOS-dependent BC cells using TC11 and its related sulfonamide-indolinone hybrids. Further investigation is warranted to identify their precise/exact molecular target.

Comparative studies on the chemical composition and pharmacological effects of vinegar-processed antler glue modified from Lei Gong Pao Zhi Lun and traditional water-processed antler glue

ETHNOPHARMACOLOGICAL RELEVANCE

Antler glue is a classic medicinal to enhance sexual function in traditional Chinese medicine (TCM), which was first recorded in Shen Nong Ben Cao Jing (Shennong's Classic of the Materia Medica). Vinegar-processing is a classic method of processing traditional Chinese medicine. The method of preparing antler glue by boiling antlers in vinegar and then concentrating them is recorded in Lei Gong Pao Zhi Lun (Master Lei's Discourse on Medicinal Processing). In modern times, the typical processing method of antler glue is water extraction and concentration. However, it is not clear whether there is a difference in the effect of these two processing methods on the chemical composition and pharmacological activity of antler glue.

AIM OF THE STUDY

The Chinese Pharmacopoeia (2020) records that the processing method of antler glue is water extraction and concentration. But Lei Gong Pao Zhi Lun differs in Chinese Pharmacopoeia (2020), which records the processing method of vinegar extraction and concentration. The effect of the two processing methods on antler glue's chemical composition and pharmacological activity is unknown. So this study aimed to elucidate the difference between different processing methods on the chemical composition and the treatment effect on oligoasthenospermia of antler glue.

MATERIALS AND METHODS

So the automatic amino acid analyzer is used to determine the amino acid content of two different processing methods of antler glue. Proteomics was performed to detect the protein components of two different processing methods of antler glue and analyze them. Cyclophosphamide-induced mice models of oligoasthenospermia were used to study the different pharmacological effects of antler glue in two different processing methods. An automatic sperm analyzer observed the quantity and quality of sperm in mice epididymis. Serum sex hormone testosterone (T), luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels in mice were tested using the enzyme-linked immunosorbent assay (ELISA) kits. Hematoxylin-eosin (H&E) staining was used to analyze pathological alterations in mouse testicular tissue. The transcriptome has been used to reveal the potential mechanism of antler glue in treating oligoasthenospermia. Mitochondrial complex activity assay kits were used to assay the activity of mitochondrial respiratory chain complex I-V in mouse testicular tissue. Western blot was used to determine the expression of related proteins in mouse testicular tissue.

RESULTS

Vinegar-processing can increase the alanine, proline, and glycine content in antler glue, reduce the length of protein peptides in antler glue, and produce a variety of unique proteins. Vinegar-processed antler glue (VAG) increased sperm density, sperm survival, sperm viability, and serum sex hormone levels in oligozoospermic mice. It reversed testicular damage caused by cyclophosphamide, and the effects were differently superior to those of water-processed antler glue (WAG). In addition, transcriptomics and related experiments have shown that VAG can increase the expression of Ndufa2, Uqcr11, Cox6b1, and Atp5i genes and proteins in mouse testis, thus promoting adenosine diphosphate (ATP) synthesis by increasing the activity of mitochondrial respiratory chain complexes I, III, IV and V. By promoting the oxidative phosphorylation process to produce more ATP, VAG can achieve the therapeutic effect of oligoasthenospermia.

CONCLUSION

Vinegar-processing method can increase the content of active ingredients in antler glue. VAG increases ATP levels in the testes by promoting the process of oxidative phosphorylation to treat oligozoospermia.

Nanosecond Pulsed Electric Fields (nsPEFs) Modulate Electron Transport in the Plasma Membrane and the Mitochondria

Nanosecond pulsed electric fields (nsPEFs) are a pulsed power technology known for ablating tumors, but they also modulate diverse biological mechanisms. Here we show that nsPEFs regulate trans-plasma membrane electron transport (tPMET) rates in the plasma membrane redox system (PMRS) shown as a reduction of the cell-impermeable, WST-8 tetrazolium dye. At lower charging conditions, nsPEFs enhance, and at higher charging conditions inhibit tPMET in H9c2 non-cancerous cardiac myoblasts and 4T1-luc breast cancer cells. This biphasic nsPEF-induced modulation of tPMET is typical of a hormetic stimulus that is beneficial and stress-adaptive at lower levels and damaging at higher levels. NsPEFs also attenuated mitochondrial electron transport system (ETS) activity (O2 consumption) at Complex I when coupled and uncoupled to oxidative phosphorylation. NsPEFs generated more reactive oxygen species (ROS) in mitochondria (mROS) than in the cytosol (cROS) in non-cancer H9c2 heart cells but more cROS than mROS in 4T1-luc cancer cells. Under lower charging conditions, nsPEFs support glycolysis while under higher charging conditions, nsPEFs inhibit electron transport in the PMRS and the mitochondrial ETS producing ROS, ultimately causing cell death. The impact of nsPEF on ETS presents a new paradigm for considering nsPEF modulation of redox functions, including redox homeostasis and metabolism.

Chlorogenic acid protects against intestinal inflammation and injury by inactivating the mtDNA-cGAS-STING signaling pathway in broilers under necrotic enteritis challenge

This study aimed to determine the effects of chlorogenic acid (CGA) on the growth performance, intestinal health, immune response, and mitochondrial DNA (mtDNA)-cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway in broilers under necrotic enteritis (NE) challenge. The 180 one-day-old male Cobb 500 broilers with similar body weight of 44.59 ± 1.39 g were randomly allocated into 3 groups. The groups were control diet (Control group), control diet + NE challenge (NE group), and control diet + 500 mg/kg CGA + NE challenge (NE + CGA group), with 6 replicates per treatment. All broilers except the Control group were given sporulated coccidian oocysts (d 14) and Clostridium perfringens (d 19-21) by oral gavage. Our findings showed that CGA improved the growth performance and intestinal morphology in broilers under NE challenge. CGA supplementation elevated the barrier function in broilers under NE challenge, which reflected in the decreased serum concentrations of D-lactate and diamine oxidase, and upregulated jejunal protein expression of occludin. CGA supplementation also improved the immune function, which reflected in the increased concentrations and gene expressions of anti-inflammatory factors, and decreased concentrations and gene expressions of proinflammatory factors. CGA supplementation further enhanced intestinal cell proliferation and differentiation, which manifested in the increased number of goblet cells and positive cells of proliferating cell nuclear antigen on d 28 and 42. Furthermore, CGA supplementation decreased the mtDNA (d 42) and mitochondrial reactive oxygen species levels (d 28 and 42), and increased the mitochondrial membrane potential (d 42) and mitochondrial complex I (d 28 and 42) or III (d 28) activity. Broilers challenged with NE had upregulated jejunal protein expressions of cGAS, phospho-TANK-binding kinase 1, and phospho-interferon regulatory factor 7 compared with the Control group, which were downregulated after CGA supplementation. In conclusion, dietary supplementation CGA could protect against intestinal inflammation and injury by reducing the leakage of mtDNA and inactivating the cGAS-STING signaling pathway in broilers under NE challenge.

Mitochondrial dysfunction in the pathogenesis of acute pancreatitis

The mechanism of cell damage during acute pancreatitis (AP) has not been fully elucidated, and there is still a lack of specific or effective treatments. Increasing evidence has implicated mitochondrial dysfunction as a key event in the pathophysiology of AP. Mitochondrial dysfunction is closely related to calcium (Ca2+) overload, intracellular adenosine triphosphate depletion, mitochondrial permeability transition pore openings, loss of mitochondrial membrane potential, mitophagy damage and inflammatory responses. Mitochondrial dysfunction is an early triggering event in the initiation and development of AP, and this organelle damage may precede the release of inflammatory cytokines, intracellular trypsin activation and vacuole formation of pancreatic acinar cells. This review provides further insight into the role of mitochondria in both physiological and pathophysiological aspects of AP, aiming to improve our understanding of the underlying mechanism which may lead to the development of therapeutic and preventive strategies for AP.

From diabetic hyperglycemia to cerebrovascular Damage: A narrative review

Diabetes mellitus is a globally significant disease that can lead to systemic complications, particularly vascular damage, including cardiovascular and cerebrovascular diseases of relevance. The physiological changes resulting from the imbalance in blood glucose levels play a crucial role in initiating vascular endothelial damage. Elevated glucose levels can also penetrate the central nervous system, triggering diabetic encephalopathy characterized by oxidative damage to brain components and activation of alternative and neurotoxic pathways. This brain damage increases the risk of ischemic stroke, a leading cause of mortality worldwide and a major cause of disability among surviving patients. The aim of this review is to highlight important pathways related to hyperglycemic damage that extend to the brain and result in vascular dysfunction, ultimately leading to the occurrence of a stroke. Understanding how diabetes mellitus contributes to the development of ischemic stroke and its impact on patient outcomes is crucial for implementing therapeutic strategies that reduce the incidence of diabetes mellitus and its complications, ultimately decreasing morbidity and mortality associated with the disease.

Coupled chemical reactions: Effects of electric field, diffusion, and boundary control

Chemical reactions involve the movement of charges, and this paper presents a mathematical model for describing chemical reactions in electrolytes. The model is developed using an energy variational method that aligns with classical thermodynamics principles. It encompasses both electrostatics and chemical reactions within consistently defined energetic and dissipative functionals. Furthermore, the energy variation method is extended to account for open systems that involve the input and output of charge and mass. Such open systems have the capability to convert one form of input energy into another form of output energy. In particular, a two-domain model is developed to study a reaction system with self-regulation and internal switching, which plays a vital role in the electron transport chain of mitochondria responsible for ATP generation-a crucial process for sustaining life. Simulations are conducted to explore the influence of electric potential on reaction rates and switching dynamics within the two-domain system. It shows that the electric potential inhibits the oxidation reaction while accelerating the reduction reaction.

Mitochondrial quality control in health and cardiovascular diseases

Cardiovascular diseases (CVDs) are one of the primary causes of mortality worldwide. An optimal mitochondrial function is central to supplying tissues with high energy demand, such as the cardiovascular system. In addition to producing ATP as a power source, mitochondria are also heavily involved in adaptation to environmental stress and fine-tuning tissue functions. Mitochondrial quality control (MQC) through fission, fusion, mitophagy, and biogenesis ensures the clearance of dysfunctional mitochondria and preserves mitochondrial homeostasis in cardiovascular tissues. Furthermore, mitochondria generate reactive oxygen species (ROS), which trigger the production of pro-inflammatory cytokines and regulate cell survival. Mitochondrial dysfunction has been implicated in multiple CVDs, including ischemia-reperfusion (I/R), atherosclerosis, heart failure, cardiac hypertrophy, hypertension, diabetic and genetic cardiomyopathies, and Kawasaki Disease (KD). Thus, MQC is pivotal in promoting cardiovascular health. Here, we outline the mechanisms of MQC and discuss the current literature on mitochondrial adaptation in CVDs.

Effects of Walnut and Pumpkin on Selective Neurophenotypes of Autism Spectrum Disorders: A Case Study

Special diets or nutritional supplements are regularly given to treat children with autism spectrum disorder (ASD). The increased consumption of particular foods has been demonstrated in numerous trials to lessen autism-related symptoms and comorbidities. A case study on a boy with moderate autism who significantly improved after three years of following a healthy diet consisting of pumpkin and walnuts was examined in this review in connection to a few different neurophenotypes of ASD. We are able to suggest that a diet high in pumpkin and walnuts was useful in improving the clinical presentation of the ASD case evaluated by reducing oxidative stress, neuroinflammation, glutamate excitotoxicity, mitochondrial dysfunction, and altered gut microbiota, all of which are etiological variables. Using illustrated figures, a full description of the ways by which a diet high in pumpkin and nuts could assist the included case is offered.

Mitochondrial dysfunction in neurodegenerative disorders: Potential therapeutic application of mitochondrial transfer to central nervous system-residing cells

Mitochondrial dysfunction is reiteratively involved in the pathogenesis of diverse neurodegenerative diseases. Current in vitro and in vivo approaches support that mitochondrial dysfunction is branded by several molecular and cellular defects, whose impact at different levels including the calcium and iron homeostasis, energetic balance and/or oxidative stress, makes it difficult to resolve them collectively given their multifactorial nature. Mitochondrial transfer offers an overall solution since it contains the replacement of damage mitochondria by healthy units. Therefore, this review provides an introducing view on the structure and energy-related functions of mitochondria as well as their dynamics. In turn, we summarize current knowledge on how these features are deregulated in different neurodegenerative diseases, including frontotemporal dementia, multiple sclerosis, amyotrophic lateral sclerosis, Friedreich ataxia, Alzheimer´s disease, Parkinson´s disease, and Huntington's disease. Finally, we analyzed current advances in mitochondrial transfer between diverse cell types that actively participate in neurodegenerative processes, and how they might be projected toward developing novel therapeutic strategies.

Mitochondrial dynamics in health and disease: mechanisms and potential targets

Mitochondria are organelles that are able to adjust and respond to different stressors and metabolic needs within a cell, showcasing their plasticity and dynamic nature. These abilities allow them to effectively coordinate various cellular functions. Mitochondrial dynamics refers to the changing process of fission, fusion, mitophagy and transport, which is crucial for optimal function in signal transduction and metabolism. An imbalance in mitochondrial dynamics can disrupt mitochondrial function, leading to abnormal cellular fate, and a range of diseases, including neurodegenerative disorders, metabolic diseases, cardiovascular diseases and cancers. Herein, we review the mechanism of mitochondrial dynamics, and its impacts on cellular function. We also delve into the changes that occur in mitochondrial dynamics during health and disease, and offer novel perspectives on how to target the modulation of mitochondrial dynamics.

The translocase of the inner mitochondrial membrane 22-2 is required for mitochondrial membrane function during Arabidopsis seed development

The carrier translocase (also known as translocase of the inner membrane 22; TIM22 complex) is an important component of the mitochondrial protein import apparatus. However, the biological functions of AtTIM22-2 in Arabidopsis remain poorly defined. Here, we report studies on two tim22-2 mutants that exhibit defects in embryo and endosperm development, leading to seed abortion. AtTIM22-2, which was localized in mitochondria, was widely expressed in embryos and in various seedling organs. Loss of AtTIM22-2 function resulted in irregular mitochondrial cristae, decreased respiratory activity, and a lower membrane potential, together with changes in gene expression and enzyme activity related to reactive oxygen species (ROS) metabolism, leading to increased accumulation of ROS in the embryo. The levels of transcripts encoding mitochondrial protein import components were also altered in the tim22-2 mutants. Furthermore, mass spectrometry, bimolecular fluorescence complementation and co-immunoprecipitation assays revealed that AtTIM22-2 interacted with AtTIM23-2, AtB14.7 (a member of Arabidopsis OEP16 family encoded by At2G42210), and AT5G27395 (mitochondrial inner membrane translocase complex, subunit TIM44-related protein). Taken together, these results demonstrate that AtTIM22-2 is essential for maintaining mitochondrial membrane functions during seed development. These findings lay the foundations for a new model of the composition and functions of the TIM22 complex in higher plants.

Luteolin induces apoptosis by impairing mitochondrial function and targeting the intrinsic apoptosis pathway in gastric cancer cells

Gastric cancer is one of the most lethal cancers worldwide. Research has focused on exploring natural medicines to improve the systematic chemotherapy for gastric cancer. Luteolin, a natural flavonoid, possesses anticancer activities. Nevertheless, the mechanism of the anticancer effects of luteolin is still not clear. The present study aimed to verify the inhibitory effect of luteolin on gastric cancer HGC-27, MFC and MKN-45 cells and to explore the underlying mechanism. A Cell Counting Kit-8 cell viability assay, flow cytometry, western blot, an ATP content assay and an enzyme activity testing assay were used. Luteolin inhibited the proliferation of gastric cancer HGC-27, MFC and MKN-45 cells. Further, it impaired mitochondrial integrity and function by destroying the mitochondrial membrane potential, downregulating the activities of mitochondrial electron transport chain complexes (mainly complexes I, III and V), and unbalancing the expression of B cell lymphoma-2 family member proteins, eventually leading to apoptosis of gastric cancer HGC-27, MFC and MKN-45 cells. The intrinsic apoptosis pathway was involved in luteolin's anti-gastric cancer effects. Furthermore, mitochondria were the main target in luteolin-induced gastric cancer apoptosis. The present study may provide a theoretical basis for the research on the effect of luteolin on the mitochondrial metabolism in cancer cells, and pave the way for its practical application in the future.

Recent advances in small molecules for improving mitochondrial disorders

Mitochondrial disorders are observed in various human diseases, including rare genetic disorders and complex acquired pathologies. Recent advances in molecular biological techniques have dramatically expanded the understanding of multiple pathomechanisms involving mitochondrial disorders. However, the therapeutic methods for mitochondrial disorders are limited. For this reason, there is increasing interest in identifying safe and effective strategies to mitigate mitochondrial impairments. Small-molecule therapies hold promise for improving mitochondrial performance. This review focuses on the latest advances in developing bioactive compounds for treating mitochondrial disease, aiming to provide a broader perspective of fundamental studies that have been carried out to evaluate the effects of small molecules in regulating mitochondrial function. Novel-designed small molecules ameliorating mitochondrial functions are urgent for further research.

Oxidative stress and mitochondrial dysfunction of granulosa cells in polycystic ovarian syndrome

Polycystic ovarian syndrome (PCOS) is one of the leading causes of anovulatory infertility in women, affecting 5%-15% of women of reproductive age worldwide. The clinical manifestations of patients include ovulation disorders, amenorrhea, hirsutism, and obesity. Life-threatening diseases, such as endometrial cancer, type 2 diabetes, hyperlipidaemia, hypertension, and cardiovascular disease, can be distant complications of PCOS. PCOS has diverse etiologies and oxidative stress (OS) plays an important role. Mitochondria, as the core organelles of energy production, are the main source of reactive oxygen species (ROS). The process of follicular growth and development is extremely complex, and the granulosa cells (GCs) are inextricably linked to follicular development. The abnormal function of GCs may directly affect follicular development and alter many symptoms of PCOS. Significantly higher levels of OS markers and abnormal mitochondrial function in GCs have been found in patients with PCOS compared to healthy subjects, suggesting that increased OS is associated with PCOS progression. Therefore, the aim of this review was to summarize and discuss the findings suggesting that OS and mitochondrial dysfunction in GCs impair ovarian function and induce PCOS.

Neopeltolide and its synthetic derivatives: a promising new class of anticancer agents

Being the first or second cause of death worldwide, cancer represents the most significant clinical, social, and financial burden of any human illness. Despite recent progresses in cancer diagnosis and management, traditional cancer chemotherapies have shown several adverse side effects and loss of potency due to increased resistance. As a result, one of the current approaches is on with the search of bioactive anticancer compounds from natural sources. Neopeltolide is a marine-derived macrolide isolated from deep-water sponges collected off Jamaica's north coast. Its mechanism of action is still under research but represents a potentially promising novel drug for cancer therapy. In this review, we first illustrate the general structural characterization of neopeltolide, the semi-synthetic derivatives, and current medical applications. In addition, we reviewed its anticancer properties, primarily based on in vitro studies, and the possible clinical trials. Finally, we summarize the recent progress in the mechanism of antitumor action of neopeltolide. According to the information presented, we identified two principal challenges in the research, i) the effective dose which acts neopeltolide as an anticancer compound, and ii) to unequivocally establish the mechanism of action by which the compound exerts its antiproliferative effect.

Effect of Sublethal Concentrations of Metal Nanomaterials on Cell Energy Metabolism

Metallic nanomaterials (MNMs) are widely used in the medical field because of their photocatalytic, optical, electrical, electronic, antibacterial, and bactericidal properties. Despite the advantages of MNMs, there is a lack of complete understanding of their toxicological behavior and their interactions with cellular mechanisms that determine cell fate. Most of the existing studies are acute toxicity studies with high doses, which is not conducive to understanding the toxic effects and mechanisms of homeostasis-dependent organelles, such as mitochondria, which are involved in many cellular functions. In this study, four types of MNMs were used to investigate the effects of metallic nanomaterials on mitochondrial function and structure. We first characterized the four MNMs and selected the appropriate sublethal concentration for application in cells. Mitochondrial characterization, energy metabolism, mitochondrial damage, mitochondrial complex activity, and expression levels were evaluated using various biological methods. The results showed that the four types of MNMs greatly inhibited mitochondrial function and cell energy metabolism and that the material entering the mitochondria damaged the mitochondrial structure. Additionally, the complex activity of mitochondrial electron transport chains is critical for assessing the mitochondrial toxicity of MNMs, which may serve as an early warning of MNM-induced mitochondrial dysfunction and cytotoxicity.

Mitochondrial metabolism of the facultative parasite Chilodonella uncinata (Alveolata, Ciliophora)

BACKGROUND

Chilodonella uncinata is an aerobic ciliate capable of switching between being free-living and parasitic on fish fins and gills, causing tissue damage and host mortality. It is widely used as a model organism for genetic studies, but its mitochondrial metabolism has never been studied. Therefore, we aimed to describe the morphological features and metabolic characteristics of its mitochondria.

METHODS

Fluorescence staining and transmission electron microscopy (TEM) were used to observe the morphology of mitochondria. Single-cell transcriptome data of C. uncinata were annotated by the Clusters of Orthologous Genes (COG) database. Meanwhile, the metabolic pathways were constructed based on the transcriptomes. The phylogenetic analysis was also made based on the sequenced cytochrome c oxidase subunit 1 (COX1) gene.

RESULTS

Mitochondria were stained red using Mito-tracker Red staining and were stained slightly blue by DAPI dye. The cristae and double membrane structures of the mitochondria were observed by TEM. Besides, many lipid droplets were evenly distributed around the macronucleus. A total of 2594 unigenes were assigned to 23 functional classifications of COG. Mitochondrial metabolic pathways were depicted. The mitochondria contained enzymes for the complete tricarboxylic acid (TCA) cycle, fatty acid metabolism, amino acid metabolism, and cytochrome-based electron transport chain (ETC), but only partial enzymes involved in the iron-sulfur clusters (ISCs).

CONCLUSIONS

Our results showed that C. uncinata possess typical mitochondria. Stored lipid droplets inside mitochondria may be the energy storage of C. uncinata that helps its transmission from a free-living to a parasitic lifestyle. These findings also have improved our knowledge of the mitochondrial metabolism of C. uncinata and increased the volume of molecular data for future studies of this facultative parasite.

Compartment specific mitochondrial dysfunction in Drosophila knock-in model of ALS reversed by altered gene expression of OXPHOS subunits and pro-fission factor Drp1

Amyotrophic Lateral Sclerosis (ALS) is a fatal multisystem neurodegenerative disease, characterized by a loss in motor function. ALS is genetically diverse, with mutations in genes ranging from those regulating RNA metabolism, like TAR DNA-binding protein (TDP-43) and Fused in sarcoma (FUS), to those that act to maintain cellular redox homeostasis, like superoxide dismutase 1 (SOD1). Although varied in genetic origin, pathogenic and clinical commonalities are clearly evident between cases of ALS. Defects in mitochondria is one such common pathology, thought to occur prior to, rather than as a consequence of symptom onset, making these organelles a promising therapeutic target for ALS, as well as other neurodegenerative diseases. Depending on the homeostatic needs of neurons throughout life, mitochondria are normally shuttled to different subcellular compartments to regulate metabolite and energy production, lipid metabolism, and buffer calcium. While originally considered a motor neuron disease due to the dramatic loss in motor function accompanied by motor neuron cell death in ALS patients, many studies have now implicated non-motor neurons and glial cells alike. Defects in non-motor neuron cell types often preceed motor neuron death suggesting their dysfunction may initiate and/or facilitate the decline in motor neuron health. Here, we investigate mitochondria in a Drosophila Sod1 knock-in model of ALS. In depth, in vivo, examination reveals mitochondrial dysfunction evident prior to onset of motor neuron degeneration. Genetically encoded redox biosensors identify a general disruption in the electron transport chain (ETC). Compartment specific abnormalities in mitochondrial morphology is observed in diseased sensory neurons, accompanied by no apparent defects in the axonal transport machinery, but instead an increase in mitophagy in synaptic regions. The decrease in networked mitochondria at the synapse is reversed upon downregulation of the pro-fission factor Drp1. Furthermore, altered expression of specific OXPHOS subunits reverses ALS-associated defects in mitochondrial morphology and function.

Targeting Mitochondrial Dysfunction in Neurodegenerative Diseases: Expanding the Therapeutic Approaches by Plant-Derived Natural Products

Mitochondria are the primary source of energy production in neurons, supporting the high energy consumption of the nervous system. Inefficient and dysfunctional mitochondria in the central nervous system have been implicated in neurodegenerative diseases. Therefore, targeting mitochondria offers a new therapeutic opportunity for neurodegenerative diseases. Many recent studies have proposed that plant-derived natural products, as pleiotropic, safe, and readily obtainable sources of new drugs, potentially treat neurodegenerative diseases by targeting mitochondria. In this review, we summarize recent advances in targeting mitochondria in neurotherapeutics by employing plant-derived natural products. We discuss the mechanism of plant-derived natural products according to their mechanism of action on mitochondria in terms of regulating biogenesis, fusion, fission, bioenergetics, oxidative stress, calcium homeostasis, membrane potential, and mitochondrial DNA stability, as well as repairing damaged mitochondria. In addition, we discuss the potential perspectives and challenges in developing plant-derived natural products to target mitochondria, highlighting the clinical value of phytochemicals as feasible candidates for future neurotherapeutics.

Role of reactive oxygen species and mitochondrial damage in rheumatoid arthritis and targeted drugs

Rheumatoid arthritis (RA) is an autoimmune disease characterized by synovial inflammation, pannus formation, and bone and cartilage damage. It has a high disability rate. The hypoxic microenvironment of RA joints can cause reactive oxygen species (ROS) accumulation and mitochondrial damage, which not only affect the metabolic processes of immune cells and pathological changes in fibroblastic synovial cells but also upregulate the expression of several inflammatory pathways, ultimately promoting inflammation. Additionally, ROS and mitochondrial damage are involved in angiogenesis and bone destruction, thereby accelerating RA progression. In this review, we highlighted the effects of ROS accumulation and mitochondrial damage on inflammatory response, angiogenesis, bone and cartilage damage in RA. Additionally, we summarized therapies that target ROS or mitochondria to relieve RA symptoms and discuss the gaps in research and existing controversies, hoping to provide new ideas for research in this area and insights for targeted drug development in RA.

The significance of bioelectricity on all levels of organization of an organism. Part 1: From the subcellular level to cells

Bioelectricity plays an essential role in the structural and functional organization of biological organisms. In this first article of our three-part series, we summarize the importance of bioelectricity for the basic structural level of biological organization, i.e. from the subcellular level (charges, ion channels, molecules and cell organelles) to cells.

Mitochondrial dysfunction in vascular endothelial cells and its role in atherosclerosis

The mitochondria are essential organelles that generate large amounts of ATP via the electron transport chain (ECT). Mitochondrial dysfunction causes reactive oxygen species accumulation, energy stress, and cell death. Endothelial mitochondrial dysfunction is an important factor causing abnormal function of the endothelium, which plays a central role during atherosclerosis development. Atherosclerosis-related risk factors, including high glucose levels, hypertension, ischemia, hypoxia, and diabetes, promote mitochondrial dysfunction in endothelial cells. This review summarizes the physiological and pathophysiological roles of endothelial mitochondria in endothelial function and atherosclerosis.

Mechanisms of mitochondrial respiratory adaptation

Mitochondrial energetic adaptations encompass a plethora of conserved processes that maintain cell and organismal fitness and survival in the changing environment by adjusting the respiratory capacity of mitochondria. These mitochondrial responses are governed by general principles of regulatory biology exemplified by changes in gene expression, protein translation, protein complex formation, transmembrane transport, enzymatic activities and metabolite levels. These changes can promote mitochondrial biogenesis and membrane dynamics that in turn support mitochondrial respiration. The main regulatory components of mitochondrial energetic adaptation include: the transcription coactivator peroxisome proliferator-activated receptor-γ (PPARγ) coactivator 1α (PGC1α) and associated transcription factors; mTOR and endoplasmic reticulum stress signalling; TOM70-dependent mitochondrial protein import; the cristae remodelling factors, including mitochondrial contact site and cristae organizing system (MICOS) and OPA1; lipid remodelling; and the assembly and metabolite-dependent regulation of respiratory complexes. These adaptive molecular and structural mechanisms increase respiration to maintain basic processes specific to cell types and tissues. Failure to execute these regulatory responses causes cell damage and inflammation or senescence, compromising cell survival and the ability to adapt to energetically demanding conditions. Thus, mitochondrial adaptive cellular processes are important for physiological responses, including to nutrient availability, temperature and physical activity, and their failure leads to diseases associated with mitochondrial dysfunction such as metabolic and age-associated diseases and cancer.

Characterization of Mitochondrial Alterations in Aicardi-Goutières Patients Mutated in RNASEH2A and RNASEH2B Genes

Aicardi-Goutières syndrome (AGS) is a rare encephalopathy characterized by neurological and immunological features. Mitochondrial dysfunctions may lead to mitochondrial DNA (mtDNA) release and consequent immune system activation. We investigated the role of mitochondria and mtDNA in AGS pathogenesis by studying patients mutated in RNASEH2B and RNASEH2A genes. Lymphoblastoid cell lines (LCLs) from RNASEH2A- and RNASEH2B-mutated patients and healthy control were used. Transmission Electron Microscopy (TEM) and flow cytometry were used to assess morphological alterations, reactive oxygen species (ROS) production and mitochondrial membrane potential variations. Seahorse Analyzer was used to investigate metabolic alterations, and mtDNA oxidation and VDAC1 oligomerization were assessed by immunofluorescence. Western blot and RT-qPCR were used to quantify mtTFA protein and mtDNA release. Morphological alterations of mitochondria were observed in both mutated LCLs, and loss of physiological membrane potential was mainly identified in RNASEH2A LCLs. ROS production and 8-oxoGuanine levels were increased in RNASEH2B LCLs. Additionally, the VDAC1 signal was increased, suggesting a mitochondrial pore formation possibly determining mtDNA release. Indeed, higher cytoplasmic mtDNA levels were found in RNASEH2B LCLs. Metabolic alterations confirmed mitochondrial damage in both LCLs. Data highlighted mitochondrial alterations in AGS patients' LCLs suggesting a pivotal role in AGS pathogenesis.

Mitochondrial Respiratory Chain Supercomplexes: From Structure to Function

Mitochondrial oxidative phospho rylation, the center of cellular metabolism, is pivotal for the energy production in eukaryotes. Mitochondrial oxidative phosphorylation relies on the mitochondrial respiratory chain, which consists of four main enzyme complexes and two mobile electron carriers. Mitochondrial enzyme complexes also assemble into respiratory chain supercomplexes (SCs) through specific interactions. The SCs not only have respiratory functions but also improve the efficiency of electron transfer and reduce the production of reactive oxygen species (ROS). Impaired assembly of SCs is closely related to various diseases, especially neurodegenerative diseases. Therefore, SCs play important roles in improving the efficiency of the mitochondrial respiratory chain, as well as maintaining the homeostasis of cellular metabolism. Here, we review the structure, assembly, and functions of SCs, as well as the relationship between mitochondrial SCs and diseases.

Altered Liver Metabolism, Mitochondrial Function, Oxidative Status, and Inflammatory Response in Intrauterine Growth Restriction Piglets with Different Growth Patterns before Weaning

Frequent occurrence of intrauterine growth restriction (IUGR) causes huge economic losses in the pig industry. Accelerated catch-up growth (CUG) in the early stage of life could restore multiple adverse outcomes of IUGR offspring; however, there is little knowledge about this beneficial phenomenon. We previously found that nutrient absorption related to intestinal function was globally promoted in CUG-IUGR piglets before weaning, which might be the dominant reason for CUG, but what this alteration could lead to in subsequent liver metabolism is still unknown. Firstly, a Normal, CUG, and non-catch-up growth (NCUG) piglet model before weaning was established by dividing eighty litters of newborn piglets into normal birth weight (NBW) and IUGR groups according to birth weight, and those piglets with IUGR but above-average weanling body weight were considered CUG, and the piglets with IUGR still below average body weight were considered NCUG at weaning day (d 26). Liver samples were collected and then systematically compared in glycolipid metabolism, mitochondrial function, antioxidant status, and inflammatory status among these three different growth models. Enhanced hepatic uptake of fatty acids, diminished de novo synthesis of fatty acids, and increased oxidation of fatty acids were observed in CUG livers compared to Normal and NCUG. In contrast, the NCUG liver showed enhanced glucose uptake and gluconeogenesis compared to Normal and CUG. We also observed deteriorating hepatic vacuolation in NCUG piglets, while increasing hepatic lipid deposition in CUG piglets. Besides, the expression of genes related to mitochondrial energy metabolism and biogenesis was reduced in CUG piglets and the phosphorylation level of AMPK was significantly higher compared to Normal (p < 0.05). Moreover, NCUG liver showed decreased T-AOC (p < 0.01) and GSH-PX (p < 0.05), increased MDA concentrations (p < 0.01), upregulated phosphorylation levels of ERK and NF-κB (p < 0.05), and elevated pro-inflammatory factors IL-1β, IL-6 and TNF-α (p < 0.05) compared to Normal. Furthermore, correlation analysis revealed a significant positive correlation between glucose metabolism and inflammatory factors, while a negative correlation between mitochondrial function-related genes and fatty acid transport. NGUG piglets showed simultaneous enhancement of glucose uptake and gluconeogenesis, as well as reduced antioxidant capacity and increased inflammatory status, whereas CUG comes at the expense of impaired hepatic mitochondrial function and pathological fat accumulation.

Effects of Noonan Syndrome-Germline Mutations on Mitochondria and Energy Metabolism

Noonan syndrome (NS) and related Noonan syndrome with multiple lentigines (NSML) contribute to the pathogenesis of human diseases in the RASopathy family. This family of genetic disorders constitute one of the largest groups of developmental disorders with variable penetrance and severity, associated with distinctive congenital disabilities, including facial features, cardiopathies, growth and skeletal abnormalities, developmental delay/mental retardation, and tumor predisposition. NS was first clinically described decades ago, and several genes have since been identified, providing a molecular foundation to understand their physiopathology and identify targets for therapeutic strategies. These genes encode proteins that participate in, or regulate, RAS/MAPK signalling. The RAS pathway regulates cellular metabolism by controlling mitochondrial homeostasis, dynamics, and energy production; however, little is known about the role of mitochondrial metabolism in NS and NSML. This manuscript comprehensively reviews the most frequently mutated genes responsible for NS and NSML, covering their role in the current knowledge of cellular signalling pathways, and focuses on the pathophysiological outcomes on mitochondria and energy metabolism.

Mitochondrial protein dysfunction in pathogenesis of neurological diseases

Mitochondria are essential organelles for neuronal function and cell survival. Besides the well-known bioenergetics, additional mitochondrial roles in calcium signaling, lipid biogenesis, regulation of reactive oxygen species, and apoptosis are pivotal in diverse cellular processes. The mitochondrial proteome encompasses about 1,500 proteins encoded by both the nuclear DNA and the maternally inherited mitochondrial DNA. Mutations in the nuclear or mitochondrial genome, or combinations of both, can result in mitochondrial protein deficiencies and mitochondrial malfunction. Therefore, mitochondrial quality control by proteins involved in various surveillance mechanisms is critical for neuronal integrity and viability. Abnormal proteins involved in mitochondrial bioenergetics, dynamics, mitophagy, import machinery, ion channels, and mitochondrial DNA maintenance have been linked to the pathogenesis of a number of neurological diseases. The goal of this review is to give an overview of these pathways and to summarize the interconnections between mitochondrial protein dysfunction and neurological diseases.

Activated TRPA1 plays a therapeutic role in TMZ resistance in glioblastoma by altering mitochondrial dynamics

Background

Glioblastoma (GBM) represents nearly one-half of primary brain tumors, and the median survival of patients with GBM is only 14.6 months. Surgery followed by radiation with concomitant temozolomide (TMZ) therapy is currently the standard of care. However, an increasing body of evidence suggests that GBM acquires resistance to TMZ, compromising the effect of the drug. Thus, further exploration into the mechanism underlying this resistance is urgently needed. Studies have demonstrated that TMZ resistance is associated with DNA damage, followed by altered reactive oxygen species (ROS) production in mitochondria. Studies have also showed that Ca2+-related transient receptor potential (TRP) channels participate in GBM cell proliferation and metastasis, but the detailed mechanism of their involvement remain to be studied. The present study demonstrates the role played by TRPA1 in TMZ resistance in GBM and elucidates the mechanism of resistance.

Methods

U251 and SHG-44 cells were analyzed in vitro. A CCK-8 assay was performed to verify the effect of TMZ toxicity on GBM cells. Intracellular ROS levels were detected by DCFH-DA assay. A MitoSOX Red assay was performed to determine the mitochondrial ROS levels. Intracellular Ca2+ levels in the cells were determined with a Fluo-4 AM calcium assay kit. Intracellular GSH levels were determined with GSH and GSSG Assay Kit. MGMT protein, Mitochondrial fission- and fusion-, apoptosis- and motility-related protein expression was detected by western blot assay. A recombinant lentiviral vector was used to infect human U251 cells to overexpress shRNA and generate TRPA1+/+ and negative control cells. All experiments were repeated.

Results

In the U251 and SHG-44 cells, TMZ induced a small increase in the apoptosis rate and intracellular and mitochondrial ROS levels. The expression of antioxidant genes and antioxidants in these cells was also increased by TMZ. However, pretreatment with a TRPA1 agonist significantly decreased the level of antioxidant gene and antioxidants expression and enhanced intracellular and mitochondrial ROS levels. Also TMZ induced the level of MGMT protein increased, and pretreatment with a TRPA1 agonist decreased the MGMT expression. Moreover, Ca2+ influx, mitochondrial damage and cell apoptosis were promoted, and the balance between mitochondrial fission and fusion protein expression was disrupted in these GBM cells. Pretreatment with a TRPA1 inhibitor slightly enhanced the level of antioxidant gene expression and reduced the apoptosis rate. TRPA1 gene overexpression in the U251 cells was similar to that after inhibitor intervention, confirming the aforementioned experimental results.

Conclusion

The present study proved that activating TRPA1 in glioma cells, which leads to mitochondrial damage and dysfunction and ultimately to apoptosis, may decrease the TMZ resistance of GBM cells.

Quantitative Proteomics and Network Analysis of Differentially Expressed Proteins in Proteomes of Icefish Muscle Mitochondria Compared with Closely Related Red-Blooded Species

Simple Summary

Antarctic icefish are unusual in that they are the only vertebrates that survive without the protein haemoglobin. One way to try and understand the biological processes that support this anomaly is to record how proteins are regulated in these animals and to compare what we find to closely related Antarctic fish that do still retain haemoglobin. The part of the cell that most clearly utilises oxygen, which is normally transported by haemoglobin, is the mitochondrion. Therefore, we chose to catalogue all the proteins and their relative quantities in the mitochondria (pl.) from two different muscle types in two species of icefish and two species of red-blooded notothenioids. We used an approach called mass spectrometry to reveal relative amounts of the proteins from the muscles of each fish. We present analysis that shows how the connections and relative quantities of proteins differ between these species.

Abstract

Antarctic icefish are extraordinary in their ability to thrive without haemoglobin. We wanted to understand how the mitochondrial proteome has adapted to the loss of this protein. Metabolic pathways that utilise oxygen are most likely to be rearranged in these species. Here, we have defined the mitochondrial proteomes of both the red and white muscle of two different icefish species (Champsocephalus gunnari and Chionodraco rastrospinosus) and compared these with two related red-blooded Notothenioids (Notothenia rossii, Trematomus bernacchii). Liquid Chromatography-Mass spectrometry (LC-MS/MS) was used to generate and examine the proteomic profiles of the two groups. We recorded a total of 91 differentially expressed proteins in the icefish red muscle mitochondria and 89 in the white muscle mitochondria when compared with the red-blooded related species. The icefish have a relatively higher abundance of proteins involved with Complex V of oxidative phosphorylation, RNA metabolism, and homeostasis, and fewer proteins for striated muscle contraction, haem, iron, creatine, and carbohydrate metabolism. Enrichment analyses showed that many important pathways were different in both red muscle and white muscle, including the citric acid cycle, ribosome machinery and fatty acid degradation. Life in the Antarctic waters poses extra challenges to the organisms that reside within them. Icefish have successfully inhabited this environment and we surmise that species without haemoglobin uniquely maintain their physiology. Our study highlights the mitochondrial protein pathway differences between similar fish species according to their specific tissue oxygenation idiosyncrasies.

Biliary Drainage Reduces Intestinal Barrier Damage in Obstructive Jaundice by Regulating Autophagy

This study aims to investigate the mechanism by which biliary drainage reduces intestinal barrier damage in obstructive jaundice (OJ). A biliary drainage model was established in rats with OJ to detect changes in inflammatory factors and diamine oxidase (DAO), a marker of intestinal mucosal damage. The expression of autophagy-related genes in the intestinal mucosa after biliary drainage was detected using a reverse transcription-polymerase chain reaction. The rats were separated into two groups that received the autophagy activator rapamycin (RAPA) or the autophagy inhibitor 3-methyladenine (3-MA) to further investigate whether biliary drainage could alleviate the inflammatory response, oxidative stress, mitochondrial complex IV damage, and thus barrier damage in rats with OJ. The expression levels of inflammatory factors and the serum DAO content were increased in rats with OJ (P < 0.05). Biliary drainage further induced autophagy, reduced the expression levels of inflammatory factors, decreased the serum DAO content (P < 0.05), and improved intestinal mucosal damage. Administration of RAPA to OJ rats with biliary drainage increased autophagy (P < 0.05); decreased inflammatory factor secretion (P < 0.05), the serum DAO content (P < 0.05), oxidative stress (P < 0.05), and mitochondrial respiratory chain complex IV damage (P < 0.05); and ameliorated intestinal mucosal injury in OJ rats. When OJ rats were treated with 3-MA, intestinal mucosal injury, intestinal mitochondrial injury, and oxidative stress were all aggravated (P < 0.05). Biliary drainage can reduce the expression of inflammatory factors, oxidative stress, and mitochondrial injury by inducing intestinal mucosal autophagy in OJ rats, thus suggesting its role in the alleviation of intestinal mucosal injury.

The Atomically Precise Gold/Captopril Nanocluster Au25(Capt)18 Gains Anticancer Activity by Inhibiting Mitochondrial Oxidative Phosphorylation

Atomically precise gold nanoclusters (AuNCs) are an emerging class of quantum-sized nanomaterials with well-defined molecular structures and unique biophysical properties, rendering them highly attractive for biological applications. We set out to study the impact of different ligand shells of atomically similar nanoclusters on cellular recognition and response. To understand the effects of atomically precise nanoclusters with identical composition on cells, we selected two different water-soluble gold nanoclusters protected with captopril (Capt) and glutathione (GSH): Au₂₅(Capt)₁₈ (CNC) and Au₂₅(GSH)₁₈ (GNC), respectively. We demonstrated that a change of the ligand of the cluster completely changes its biological functions. Whereas both nanoclusters are capable of internalization, only CNC exhibits remarkable cytotoxicity, more specifically on cancer cells. CNC shows enhanced cytotoxicity by inhibiting the OXPHOS of mitochondria, possibly by inhibiting the ATP synthase complex of the electron transport chain (ETC), and by initiating the leakage of electrons into the mitochondrial lumen. The resulting increase in both mitochondrial and total cellular ROS triggers cell death indicated by the appearance of cellular markers of apoptosis. Remarkably, this effect of nanoclusters is independent of any external light source excitation. Our findings point to the prevailing importance of the ligand shell for applications of atomically precise nanoclusters in biology and medicine.