The Drp1-Mediated Mitochondrial Fission Protein Interactome as an Emerging Core Player in Mitochondrial Dynamics and Cardiovascular Disease Therapy

Icariin alleviates cellular injury induced by cardiac ischemia-reperfusion injury by inhibiting IRE1/JNK-induced ferroptosis

BACKGROUND

Ischemia-induced cellular damage and stress responses significantly impact cellular viability and function. Icariin (ICA), known for its protective effects, has been studied to understand its role in mitigating oxygen-glucose deprivation/reperfusion (OGD/R)-induced endoplasmic reticulum (ER) stress and ferroptosis in H9C2 cardiomyoblast cells.

METHODS

We employed an in vitro OGD/R model using H9C2 cells. ICA's effects were analyzed across multiple concentrations. Key indicators of ER stress, autophagy, and ferroptosis-including markers like Bip, PERK, IRE1, ATF6, P62, FTH1, LC3II/LC3I, and NCOA4-were assessed using Western blotting, electron microscopy, and biochemical assays. Additionally, the role of the IRE1/JNK pathway in mitochondrial dynamics and its influence on mitochondrial dynamics protein was explored through specific inhibition and activation experiments.

RESULTS

ICA significantly reduced the activation of UPR pathways, decreased autophagic vacuole formation, and maintained cell viability in response to OGD/R and Erastin-induced ferroptosis. These protective effects were associated with modulated autophagic processes, reduced lipid peroxidation, and decreased ferrous ion accumulation. Inhibition of the IRE1/JNK pathway and subsequent Drp1 activity demonstrated reduced mitochondrial recruitment and mitophagy, correlating with decreased ferroptosis markers and improved cell survival.

CONCLUSION

Our findings highlight ICA's potential in modulating IRE1/JNK pathway, autophagy, providing a therapeutic avenue for mitigating ferroptosis in myocardial ischemia-reperfusion injury (MIRI).

LC-Orbitrap HRMS-Based Proteomics Reveals Novel Mitochondrial Dynamics Regulatory Proteins Associated with RasV12-Induced Glioblastoma (GBM) of Drosophila

Glioblastoma multiforme (GBM) is the most prevalent and aggressive brain tumor found in adult humans with a poor prognosis and average survival of 14-15 months. In order to have a comprehensive understanding of proteome and identify novel therapeutic targets, this study focused mainly on the differentially abundant proteins (DAPs) of RasV12-induced GBM. RasV12 is a constitutively active Ras mutant form essential for tumor progression by continuously activating signaling pathways leading to uncontrolled tumor growth. This study used a transgenic Drosophila model with RasV12 overexpression using the repo-GAL4 driver line, specifically in glial cells, to study GBM. The high-resolution mass spectrometry (HRMS)-based proteomic analysis of the GBM larval central nervous system identified three novel DAPs specific to mitochondria. These DAPs, probable maleylacetoacetate isomerase 2 (Q9VHD2), bifunctional methylene tetrahydrofolate dehydrogenase (Q04448), and glutamine synthetase1 (P20477), identified through HRMS were further validated by qRT-PCR. The protein-protein interaction analysis revealed interactions between RasV12 and DAPs, with functional links to mitochondrial dynamics regulators such as Drp1, Marf, Parkin, and HtrA2. Notably, altered expressions of Q9VHD2, P20477, and Q04448 were observed during GBM progression, which offers new insights into the involvement of mitochondrial dynamic regulators in RasV12-induced GBM pathophysiology.

Ventilator-induced diaphragm dysfunction: phenomenology and mechanism(s) of pathogenesis

Mechanical ventilation (MV) is used to support ventilation and pulmonary gas exchange in patients during critical illness and surgery. Although MV is a life-saving intervention for patients in respiratory failure, an unintended side-effect of MV is the rapid development of diaphragmatic atrophy and contractile dysfunction. This MV-induced diaphragmatic weakness is labelled as 'ventilator-induced diaphragm dysfunction' (VIDD). VIDD is an important clinical problem because diaphragmatic weakness is a risk factor for the failure to wean patients from MV. Indeed, the inability to remove patients from ventilator support results in prolonged hospitalization and increased morbidity and mortality. The pathogenesis of VIDD has been extensively investigated, revealing that increased mitochondrial production of reactive oxygen species within diaphragm muscle fibres promotes a cascade of redox-regulated signalling events leading to both accelerated proteolysis and depressed protein synthesis. Together, these events promote the rapid development of diaphragmatic atrophy and contractile dysfunction. This review highlights the MV-induced changes in the structure/function of diaphragm muscle and discusses the cell-signalling mechanisms responsible for the pathogenesis of VIDD. This report concludes with a discussion of potential therapeutic opportunities to prevent VIDD and suggestions for future research in this exciting field.

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.

Mitochondrial fragmentation in early differentiation of human MB135 myoblasts: Role of mitochondrial ROS production in the absence of depolarization

AIMS

Study of the role of mitochondria-generated reactive oxygen species (mtROS) and mitochondrial polarization in mitochondrial fragmentation at the initial stages of myogenesis.

MAIN METHODS

Mitochondrial morphology, Drp1 protein phosphorylation, mitochondrial electron transport chain components content, mtROS and mitochondrial lipid peroxidation levels, and mitochondrial polarization were evaluated on days 1 and 2 of human MB135 myoblasts differentiation. A mitochondria-targeted antioxidant SkQ1 was used to elucidate the effect of mtROS on mitochondria.

KEY FINDINGS

In immortalized human MB135 myoblasts, mitochondrial fragmentation began on day 1 of differentiation before the myoblast fusion. This fragmentation was preceded by dephosphorylation of p-Drp1 (Ser-637). On day 2, an increase in the content of some mitochondrial proteins was observed, indicating mitochondrial biogenesis stimulation. Furthermore, we found that myogenic differentiation, even on day 1, was accompanied both by an increased production of mtROS, and lipid peroxidation of the inner mitochondrial membrane. SkQ1 blocked these effects and partially reduced the level of mitochondrial fragmentation, but did not affect the dephosphorylation of p-Drp1 (Ser-637). Importantly, mitochondrial fragmentation at early stages of MB135 differentiation was not accompanied by depolarization, as an important stimulus for mitochondrial fragmentation.

SIGNIFICANCE

Mitochondrial fragmentation during early myogenic differentiation depends on mtROS production rather than mitochondrial depolarization. SkQ1 only partially inhibited mitochondrial fragmentation, without significant effects on mitophagy or early myogenic differentiation.

Multifaceted role of dynamin-related protein 1 in cardiovascular disease: From mitochondrial fission to therapeutic interventions

Mitochondria are central to cellular energy production and metabolic regulation, particularly in cardiomyocytes. These organelles constantly undergo cycles of fusion and fission, orchestrated by key proteins like Dynamin-related Protein 1 (Drp-1). This review focuses on the intricate roles of Drp-1 in regulating mitochondrial dynamics, its implications in cardiovascular health, and particularly in myocardial infarction. Drp-1 is not merely a mediator of mitochondrial fission; it also plays pivotal roles in autophagy, mitophagy, apoptosis, and necrosis in cardiac cells. This multifaceted functionality is often modulated through various post-translational alterations, and Drp-1's interaction with intracellular calcium (Ca2 + ) adds another layer of complexity. We also explore the pathological consequences of Drp-1 dysregulation, including increased reactive oxygen species (ROS) production and endothelial dysfunction. Furthermore, this review delves into the potential therapeutic interventions targeting Drp-1 to modulate mitochondrial dynamics and improve cardiovascular outcomes. We highlight recent findings on the interaction between Drp-1 and sirtuin-3 and suggest that understanding this interaction may open new avenues for therapeutically modulating endothelial cells, fibroblasts, and cardiomyocytes. As the cardiovascular system increasingly becomes the focal point of aging and chronic disease research, understanding the nuances of Drp-1's functionality can lead to innovative therapeutic approaches.

Role of mitochondrial homeostasis in D-galactose-induced cardiovascular ageing from bench to bedside

Ageing is an inevitable phenomenon which affects the cellular to the organism level in the progression of the time. Oxidative stress and inflammation are now widely regarded as the key processes involved in the aging process, which may then cause significant harm to mitochondrial DNA, leading to apoptosis. Normal circulatory function is a significant predictor of disease-free life expectancy. Indeed, disorders affecting the cardiovascular system, which are becoming more common, are the primary cause of worldwide morbidity, disability, and mortality. Cardiovascular aging may precede or possibly underpin overall, age-related health decline. Numerous studies have foundmitochondrial mechanistc approachplays a vital role in the in the onset and development of aging. The D-galactose (D-gal)-induced aging model is well recognized and commonly used in the aging study. In this review we redeposit the association of the previous and current studies on mitochondrial homeostasis and its underlying mechanisms in D-galactose cardiovascular ageing. Further we focus the novel and the treatment strategies to combat the major complication leading to the cardiovascular ageing.

Bcl-2 Orthologues, Buffy and Debcl, Can Suppress Drp1-Dependent Age-Related Phenotypes in Drosophila

The relationship of Amyotrophic Lateral Sclerosis, Parkinson's disease, and other age-related neurodegenerative diseases with mitochondrial dysfunction has led to our study of the mitochondrial fission gene Drp1 in Drosophila melanogaster and aspects of aging. Previously, the Drp1 protein has been demonstrated to interact with the Drosophila Bcl-2 mitochondrial proteins, and Drp1 mutations can lead to mitochondrial dysfunction and neuronal loss. In this study, the Dopa decarboxylase-Gal4 (Ddc-Gal4) transgene was exploited to direct the expression of Drp1 and Drp1-RNAi transgenes in select neurons. Here, the knockdown of Drp1 seems to compromise locomotor function throughout life but does not alter longevity. The co-expression of Buffy suppresses the poor climbing induced by the knockdown of the Drp1 function. The consequences of Drp1 overexpression, which specifically reduced median lifespan and diminished climbing abilities over time, can be suppressed through the directed co-overexpression of pro-survival Bcl-2 gene Buffy or by the co-knockdown of the pro-cell death Bcl-2 homologue Debcl. Alteration of the expression of Drp1 acts to phenocopy neurodegenerative disease phenotypes in Drosophila, while overexpression of Buffy can counteract or rescue these phenotypes to improve overall health. The diminished healthy aging due to either the overexpression of Drp1 or the RNA interference of Drp1 has produced novel Drosophila models for investigating mechanisms underlying neurodegenerative disease.

Role of mitochondria in inflammatory lung diseases

Mitochondria play a significant and varied role in inflammatory lung disorders. Mitochondria, known as the powerhouse of the cell because of their role in producing energy, are now recognized as crucial regulators of inflammation and immunological responses. Asthma, chronic obstructive pulmonary disease, and acute respiratory distress syndrome are characterized by complex interactions between immune cells, inflammatory substances, and tissue damage. Dysfunctional mitochondria can increase the generation of reactive oxygen species (ROS), triggering inflammatory pathways. Moreover, mitochondrial failure impacts cellular signaling, which in turn affects the expression of molecules that promote inflammation. In addition, mitochondria have a crucial role in controlling the behavior of immune cells, such as their activation and differentiation, which is essential in the development of inflammatory lung diseases. Their dynamic behavior, encompassing fusion, fission, and mitophagy, also impacts cellular responses to inflammation and oxidative stress. Gaining a comprehensive understanding of the intricate correlation between mitochondria and lung inflammation is essential in order to develop accurate treatment strategies. Targeting ROS generation, dynamics, and mitochondrial function may offer novel approaches to treating inflammatory lung diseases while minimizing tissue damage. Additional investigation into the precise contributions of mitochondria to lung inflammation will provide significant knowledge regarding disease mechanisms and potential therapeutic approaches. This review will focus on how mitochondria in the lung regulate these processes and their involvement in acute and chronic lung diseases.

Nanobodies as novel tools to monitor the mitochondrial fission factor Drp1

In cells, mitochondria undergo constant fusion and fission. An essential factor for fission is the mammalian dynamin-related protein 1 (Drp1). Dysregulation of Drp1 is associated with neurodegenerative diseases including Parkinson's, cardiovascular diseases and cancer, making Drp1 a pivotal biomarker for monitoring mitochondrial status and potential pathophysiological conditions. Here, we developed nanobodies (Nbs) as versatile binding molecules for proteomics, advanced microscopy and live cell imaging of Drp1. To specifically enrich endogenous Drp1 with interacting proteins for proteomics, we functionalized high-affinity Nbs into advanced capture matrices. Furthermore, we detected Drp1 by bivalent Nbs combined with site-directed fluorophore labelling in super-resolution STORM microscopy. For real-time imaging of Drp1, we intracellularly expressed fluorescently labelled Nbs, so-called chromobodies (Cbs). To improve the signal-to-noise ratio, we further converted Cbs into a "turnover-accelerated" format. With these imaging probes, we visualized the dynamics of endogenous Drp1 upon compound-induced mitochondrial fission in living cells. Considering the wide range of research applications, the presented Nb toolset will open up new possibilities for advanced functional studies of Drp1 in disease-relevant models.

Mesenchymal Stem Cell Membrane-Camouflaged Liposomes for Biomimetic Delivery of Cyclosporine A for Hepatic Ischemia-Reperfusion Injury Prevention

Hepatic ischemia-reperfusion injury (HIRI) is a prevalent issue during liver resection and transplantation, with currently no cure or FDA-approved therapy. A promising drug, Cyclosporin A (CsA), ameliorates HIRI by maintaining mitochondrial homeostasis but has systemic side effects due to its low bioavailability and high dosage requirements. This study introduces a biomimetic CsA delivery system that directly targets hepatic lesions using mesenchymal stem cell (MSC) membrane-camouflaged liposomes. These hybrid nanovesicles (NVs), leveraging MSC-derived proteins, demonstrate efficient inflammatory chemotaxis, transendothelial migration, and drug-loading capacity. In a HIRI mouse model, the biomimetic NVs accumulated at liver injury sites entered hepatocytes, and significantly reduced liver damage and restore function using only one-tenth of the CsA dose typically required. Proteomic analysis verifies the protection mechanism, which includes reactive oxygen species inhibition, preservation of mitochondrial integrity, and reduced cellular apoptosis, suggesting potential for this biomimetic strategy in HIRI intervention.

Mitochondrial targeted antioxidants as potential therapy for huntington's disease

Huntington's disease (HD) is an inherited neurodegenerative disorder caused by an expansion in CAG repeat on huntington (Htt) gene, leading to a degeneration of GABAergic medium spiny neurons (MSNs) in the striatum, resulting in the generation of reactive oxygen species, and decrease antioxidant activity. These pathophysiological alterations impair mitochondrial functions, leading to an increase in involuntary hyperkinetic movement. However, researchers investigated the neuroprotective effect of antioxidants using various animal models. Still, their impact is strictly limited to curtailing oxidative stress and increasing the antioxidant enzyme in the brain, which is less effective in HD. Meanwhile, researchers discovered Mitochondria-targeted antioxidants (MTAXs) that can improve mitochondrial functions and antioxidant activity through the modulation of mitochondrial signaling pathways, including peroxisome proliferator-activated receptor (PPAR)-coactivator 1 (PGC-1α), dynamin-related protein 1 (Drp1), mitochondrial fission protein 1 (Fis1), and Silent mating type information regulation 2 homolog 1 (SIRT-1), showing neuroprotective effects in HD. The present review discusses the clinical and preclinical studies that investigate the neuroprotective effect of MTAXs (SS31, XJB-5-131, MitoQ, bezafibrate, rosiglitazone, meldonium, coenzyme Q10, etc.) in HD. This brief literature review will help to understand the relevance of MTAXs in HD and enlighten the importance of MTAXs in future drug discovery and development.

Altered Mitochondrial Function in MASLD: Key Features and Promising Therapeutic Approaches

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as nonalcoholic fatty liver disease (NAFLD), encompasses a range of liver conditions from steatosis to nonalcoholic steatohepatitis (NASH). Its prevalence, especially among patients with metabolic syndrome, highlights its growing global impact. The pathogenesis of MASLD involves metabolic dysregulation, inflammation, oxidative stress, genetic factors and, notably, mitochondrial dysfunction. Recent studies underscore the critical role of mitochondrial dysfunction in MASLD's progression. Therapeutically, enhancing mitochondrial function has gained interest, along with lifestyle changes and pharmacological interventions targeting mitochondrial processes. The FDA's approval of resmetirom for metabolic-associated steatohepatitis (MASH) with fibrosis marks a significant step. While resmetirom represents progress, further research is essential to understand MASLD-related mitochondrial dysfunction fully. Innovative strategies like gene editing and small-molecule modulators, alongside lifestyle interventions, can potentially improve MASLD treatment. Drug repurposing and new targets will advance MASLD therapy, addressing its increasing global burden. Therefore, this review aims to provide a better understanding of the role of mitochondrial dysfunction in MASLD and identify more effective preventive and treatment strategies.

Targeting Mitochondrial Dysfunction and Reactive Oxygen Species for Neurodegenerative Disease Treatment

Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common neurodegenerative diseases, and they affect millions of people worldwide, particularly older individuals. Therefore, there is a clear need to develop novel drug targets for the treatment of age-related neurodegenerative diseases. Emerging evidence suggests that mitochondrial dysfunction and reactive oxygen species (ROS) generation play central roles in the onset and progression of neurodegenerative diseases. Mitochondria are key regulators of respiratory function, cellular energy adenosine triphosphate production, and the maintenance of cellular redox homeostasis, which are essential for cell survival. Mitochondrial morphology and function are tightly regulated by maintaining a balance among mitochondrial fission, fusion, biogenesis, and mitophagy. In this review, we provide an overview of the main functions of mitochondria, with a focus on recent progress highlighting the critical role of ROS-induced oxidative stress, dysregulated mitochondrial dynamics, mitochondrial apoptosis, mitochondria-associated inflammation, and impaired mitochondrial function in the pathogenesis of age-related neurodegenerative diseases, such as AD and PD. We also discuss the potential of mitochondrial fusion and biogenesis enhancers, mitochondrial fission inhibitors, and mitochondria-targeted antioxidants as novel drugs for the treatment of these diseases.

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.

Serine 39 in the GTP-binding domain of Drp1 is involved in shaping mitochondrial morphology

Continuous fusion and fission are critical for mitochondrial health. In this study, we further characterize the role played by dynamin-related protein 1 (Drp1) in mitochondrial fission. We show that a single amino acid change in Drp1 at position 39 from serine to alanine (S39A) within the GTP-binding (GTPase) domain results in a fused mitochondrial network in human SH-SY5Y neuroblastoma cells. Interestingly, the phosphorylation of Ser-616 and Ser-637 of Drp1 remains unaffected by the S39A mutation, and mitochondrial bioenergetic profile and cell viability in the S39A mutant were comparable to those observed in the control. This leads us to propose that the serine 39 residue of Drp1 plays a crucial role in mitochondrial distribution through its involvement in the GTPase activity. Furthermore, this amino acid mutation leads to structural anomalies in the mitochondrial network. Taken together, our results contribute to a better understanding of the function of the Drp1 protein.

SS-31 treatment ameliorates cardiac mitochondrial morphology and defective mitophagy in a murine model of Barth syndrome

Barth syndrome (BTHS) is a lethal rare genetic disorder, which results in cardiac dysfunction, severe skeletal muscle weakness, immune issues and growth delay. Mutations in the TAFAZZIN gene, which is responsible for the remodeling of the phospholipid cardiolipin (CL), lead to abnormalities in mitochondrial membrane, including alteration of mature CL acyl composition and the presence of monolysocardiolipin (MLCL). The dramatic increase in the MLCL/CL ratio is the hallmark of patients with BTHS, which is associated with mitochondrial bioenergetics dysfunction and altered membrane ultrastructure. There are currently no specific therapies for BTHS. Here, we showed that cardiac mitochondria isolated from TAFAZZIN knockdown (TazKD) mice presented abnormal ultrastructural membrane morphology, accumulation of vacuoles, pro-fission conditions and defective mitophagy. Interestingly, we found that in vivo treatment of TazKD mice with a CL-targeted small peptide (named SS-31) was able to restore mitochondrial morphology in tafazzin-deficient heart by affecting specific proteins involved in dynamic process and mitophagy. This agrees with our previous data showing an improvement in mitochondrial respiratory efficiency associated with increased supercomplex organization in TazKD mice under the same pharmacological treatment. Taken together our findings confirm the beneficial effect of SS-31 in the amelioration of tafazzin-deficient dysfunctional mitochondria in a BTHS animal model.

Moderate-Intensity Exercise Enhances Mitochondrial Biogenesis Markers in the Skeletal Muscle of a Mouse Model Affected by Diet-Induced Obesity

Skeletal muscle is composed of bundles of muscle fibers with distinctive characteristics. Oxidative muscle fiber types contain higher mitochondrial content, relying primarily on oxidative phosphorylation for ATP generation. Notably, as a result of obesity, or following prolonged exposure to a high-fat diet, skeletal muscle undergoes a shift in fiber type toward a glycolytic type. Mitochondria are highly dynamic organelles, constantly undergoing mitochondrial biogenesis and dynamic processes. Our study aims to explore the impact of obesity on skeletal muscle mitochondrial biogenesis and dynamics and also ascertain whether the skeletal muscle fiber type shift occurs from the aberrant mitochondrial machinery. Furthermore, we investigated the impact of exercise in preserving the oxidative muscle fiber types despite obesity. Mice were subjected to a normal standard chow and water or high-fat diet with sugar water (HFS) with or without exercise training. After 12 weeks of treatment, the HFS diet resulted in a noteworthy reduction in the markers of mitochondrial content, which was recovered by exercise training. Furthermore, higher mitochondrial biogenesis markers were observed in the exercised group with a subsequent increase in the mitochondrial fission marker. In conclusion, these findings imply a beneficial impact of moderate-intensity exercise on the preservation of oxidative capacity in the muscle of obese mouse models.

Mitochondrial metabolism regulation and epigenetics in hypoxia

The complex and dynamic interaction between cellular energy control and gene expression modulation is shown by the intersection between mitochondrial metabolism and epigenetics in hypoxic environments. Poor oxygen delivery to tissues, or hypoxia, is a basic physiological stressor that sets off a series of reactions in cells to adapt and endure oxygen-starved environments. Often called the "powerhouse of the cell," mitochondria are essential to cellular metabolism, especially regarding producing energy through oxidative phosphorylation. The cellular response to hypoxia entails a change in mitochondrial metabolism to improve survival, including epigenetic modifications that control gene expression without altering the underlying genome. By altering the expression of genes involved in angiogenesis, cell survival, and metabolism, these epigenetic modifications help cells adapt to hypoxia. The sophisticated interplay between mitochondrial metabolism and epigenetics in hypoxia is highlighted by several important points, which have been summarized in the current article. Deciphering the relationship between mitochondrial metabolism and epigenetics during hypoxia is essential to understanding the molecular processes that regulate cellular adaptation to reduced oxygen concentrations.

Exploring neuroadaptive cellular pathways in chronic morphine exposure: An in-vitro analysis of cabergoline and Mdivi-1 co-treatment effects on the autophagy-apoptosis axis

The complex impacts of prolonged morphine exposure continue to be a significant focus in the expanding area of addiction studies. This research investigates the effectiveness of a combined treatment using Cabergoline and Mdivi-1 to counteract the neuroadaptive changes caused by in vitro morphine treatment. The impact of Methadone, Cabergoline, and a combination of Cabergoline and Mdivi-1 on the cellular and molecular responses associated with Morphine-induced changes was studied in human Neuroblastoma (SK-N-MC) and Glioblastoma (U87-MG) cell lines that were exposed to prolong Morphine treatment. Cabergoline and Mdivi-1 combined treatment effectively influenced the molecular alterations associated with neuroadaptation in chronic morphine-exposed neural cells. This combination therapy normalized autophagy and reduced oxidative stress by enhancing total-antioxidant capacity, mitigating apoptosis, restoring BDNF expression, and balancing apoptotic elements. Our research outlines morphine's dual role in modulating mitochondrial dynamics via the dysregulation of the autophagy-apoptosis axis. This emphasizes the significant involvement of DRP1 activity in neurological adaptation processes, as well as disturbances in the dopaminergic pathway during in vitro chronic exposure to morphine in neural cells. This study proposes a novel approach by recommending the potential effectiveness of combining Cabergoline and Mdivi-1 to modulate the neuroadaptations caused by morphine. Additionally, we identified BDNF and PCNA in neural cells as potential neuroprotective markers for assessing the effectiveness of drugs against opioid toxicity, emphasizing the need for further validation. The study uncovers diverse effects observed in pretreated morphine glioblastoma cells under treatment with Cabergoline and methadone. This highlights the potential for new treatments in the DRD2 pathway and underscores the importance of investigating the interplay between autophagy and apoptosis to advance research in managing cancer-related pain. The study necessitates an in-depth investigation into the relationship between autophagy and apoptosis, with a specific emphasis on protein interactions and the dynamics of cell signaling.

TMAO promotes vascular endothelial cell pyroptosis via the LPEAT-mitophagy pathway

Trimethylamine N-oxide (TMAO) is a novel risk factor for atherosclerosis, and its underlying regulatory mechanisms are under intensive investigation. Inflammation-related vascular endothelial damage is the major driver in atherogenic process. Pyroptosis, a type of proinflammatory programmed cell death, has been proved to promote the initiation and progression of atherosclerosis. In our study, we found that TMAO triggered endothelial cells excessive mitophagy, thereby facilitating pyroptosis. This process is mediated by the upexpression of phosphatidylethanolamine acyltransferase (LPEAT). These findings provide insights into TMAO-induced vascular endothelial cell damage and suggest that LPEAT may be a valuable target for the prevention and treatment of atherosclerosis.

Dysfunctional mitochondria elicit bioenergetic decline in the aged heart

Aging represents a complex biological progression affecting the entire body, marked by a gradual decline in tissue function, rendering organs more susceptible to stress and diseases. The human heart holds significant importance in this context, as its aging process poses life-threatening risks. It entails macroscopic morphological shifts and biochemical changes that collectively contribute to diminished cardiac function. Among the numerous pivotal factors in aging, mitochondria play a critical role, intersecting with various molecular pathways and housing several aging-related agents. In this comprehensive review, we provide an updated overview of the functional role of mitochondria in cardiac aging.

Current updates on metabolites and its interlinked pathways as biomarkers for diabetic kidney disease: A systematic review

Diabetic kidney disease (DKD) is a major microvascular complication of diabetes mellitus (DM) that poses a serious risk as it can lead to end-stage renal disease (ESRD). DKD is linked to changes in the diversity, composition, and functionality of the microbiota present in the gastrointestinal tract. The interplay between the gut microbiota and the host organism is primarily facilitated by metabolites generated by microbial metabolic processes from both dietary substrates and endogenous host compounds. The production of numerous metabolites by the gut microbiota is a crucial factor in the pathogenesis of DKD. However, a comprehensive understanding of the precise mechanisms by which gut microbiota and its metabolites contribute to the onset and progression of DKD remains incomplete. This review will provide a summary of the current scenario of metabolites in DKD and the impact of these metabolites on DKD progression. We will discuss in detail the primary and gut-derived metabolites in DKD, and the mechanisms of the metabolites involved in DKD progression. Further, we will address the importance of metabolomics in helping identify potential DKD markers. Furthermore, the possible therapeutic interventions and research gaps will be highlighted.

The role of DRP1 mediated mitophagy in HT22 cells apoptosis induced by silica nanoparticles

Silica nanoparticles (SiNPs) are widely used in the biomedical field and can enter the central nervous system through the blood-brain barrier, causing damage to hippocampal neurons. However, the specific mechanism remains unclear. In this experiment, HT22 cells were selected as the experimental model in vitro, and the survival rate of cells under the action of SiNPs was detected by MTT method, reactive oxygen species (ROS), lactate dehydrogenase (LDH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and adenosine triphosphate (ATP) were tested by the kit, the ultrastructure of the cells was observed by transmission electron microscope, membrane potential (MMP), calcium ion (Ca2+) and apoptosis rate were measured by flow cytometry, and the expressions of mitochondrial functional protein, mitochondrial dynein, mitochondrial autophagy protein as well as apoptosis related protein were detected by Western blot. The results showed that cell survival rate, SOD, CAT, GSH-Px, ATP and MMP gradually decreased with the increase of SiNPs concentration, while intracellular ROS, Ca2+, LDH and apoptosis rate increased with the increase of SiNPs concentration. In total cellular proteins,the expressions of mitochondrial functional proteins VDAC and UCP2 gradually increased, the expression of mitochondrial dynamic related protein DRP1 increased while the expressions of OPA1 and Mfn2 decreased. The expressions of mitophagy related proteins PINK1, Parkin and LC3Ⅱ/LC3Ⅰ increased and P62 gradually decreased, as well as the expressions of apoptosis related proteins Apaf-1, Cleaved-Caspase-3, Caspase-3, Caspase-9, Bax and Cyt-C. In mitochondrial proteins, the expressions of mitochondrial dynamic related proteins DRP1 and p-DRP1 were increased, while the expressions of OPA1 and Mfn2 were decreased. Expressions of mitochondrial autophagy associated proteins PINK1, Parkin, LC3II/LC3I increased, P62 decreased gradually, as well as the expressions of apoptosis related proteins Cleaved-Caspase-3, Caspase-3, and Caspase-9 increased, and Cyt-C expressions decreased. To further demonstrate the role of ROS and DRP1 in HT22 cell apoptosis induced by SiNPs, we selected the ROS inhibitor N-Acetylcysteine (NAC) and Dynamin-related protein 1 (DRP1) inhibitor Mdivi-1. The experimental results indicated that the above effects were remarkably improved after the use of inhibitors, further confirming that SiNPs induce the production of ROS in cells, activate DRP1, cause excessive mitochondrial division, induce mitophagy, destroy mitochondrial function and eventually lead to apoptosis.

Recent insights into the control of mitochondrial fission

Mitochondria are the powerhouse of the cell. They undergo fission and fusion to maintain cellular homeostasis. In this review, we explore the intricate regulation of mitochondrial fission at various levels, including the protein level, the post-translational modification level, and the organelle level. Malfunctions in mitochondrial fission can have detrimental effects on cells. Therefore, we also examine the association between mitochondrial fission with diseases such as breast cancer and cardiovascular disorders. We anticipate that a comprehensive investigation into the control of mitochondrial fission will pave the way for the development of innovative therapeutic strategies.

Mechanisms of mitochondrial reorganization

The cytoplasm of eukaryotes is dynamically zoned by membrane-bound and membraneless organelles. Cytoplasmic zoning allows various biochemical reactions to take place at the right time and place. Mitochondrion is a membrane-bound organelle that provides a zone for intracellular energy production and metabolism of lipids and iron. A key feature of mitochondria is their high dynamics: mitochondria constantly undergo fusion and fission, and excess or damaged mitochondria are selectively eliminated by mitophagy. Therefore, mitochondria are appropriate model systems to understand dynamic cytoplasmic zoning by membrane organelles. In this review, we summarize the molecular mechanisms of mitochondrial fusion and fission as well as mitophagy unveiled through studies using yeast and mammalian models.

Mitochondrial Dysfunction in Endothelial Progenitor Cells: Unraveling Insights from Vascular Endothelial Cells

Endothelial dysfunction is associated with several lifestyle-related diseases, including cardiovascular and neurodegenerative diseases, and it contributes significantly to the global health burden. Recent research indicates a link between cardiovascular risk factors (CVRFs), excessive production of reactive oxygen species (ROS), mitochondrial impairment, and endothelial dysfunction. Circulating endothelial progenitor cells (EPCs) are recruited into the vessel wall to maintain appropriate endothelial function, repair, and angiogenesis. After attachment, EPCs differentiate into mature endothelial cells (ECs). Like ECs, EPCs are also susceptible to CVRFs, including metabolic dysfunction and chronic inflammation. Therefore, mitochondrial dysfunction of EPCs may have long-term effects on the function of the mature ECs into which EPCs differentiate, particularly in the presence of endothelial damage. However, a link between CVRFs and impaired mitochondrial function in EPCs has hardly been investigated. In this review, we aim to consolidate existing knowledge on the development of mitochondrial and endothelial dysfunction in the vascular endothelium, place it in the context of recent studies investigating the consequences of CVRFs on EPCs, and discuss the role of mitochondrial dysfunction. Thus, we aim to gain a comprehensive understanding of mechanisms involved in EPC deterioration in relation to CVRFs and address potential therapeutic interventions targeting mitochondrial health to promote endothelial function.

Protective role of hesperetin in sorafenib-induced hepato- and neurotoxicity in mice via modulating apoptotic pathways and mitochondrial reprogramming

INTRODUCTION

Sorafenib, an FDA-approved standard chemotherapy for advanced hepatocellular carcinoma, is associated with numerous adverse effects that significantly impact patients' physiological well-being. Consequently, identifying agents that mitigate these side effects while enhancing efficacy is crucial. Hesperetin, a flavone present in fruits and vegetables, possesses antioxidant, anti-inflammatory, and anti-cancer properties. This study aimed to investigate the hepatotoxic and neurotoxic effects of sorafenib and the potential protective role of hesperetin.

MATERIALS AND METHODS

Swiss albino mice were orally administered sorafenib (100 mg/kg) alone or in combination with hesperetin (50 mg/kg) over 21 days. Behavioral assessments for anxiety and depressive-like behaviors were conducted. Additionally, evaluations encompassed apoptotic activity, mitochondrial integrity, liver enzyme levels, proliferation rates, and histopathological changes.

RESULTS

Combining hesperetin with sorafenib showed improvements in behavioral alterations, liver damage, brain mitochondrial dysfunction, and liver apoptosis compared to the sorafenib-only group in mice.

CONCLUSION

Hesperetin exhibits potential as an adjunct to sorafenib, mitigating its side effects by attenuating its toxicity, enhancing efficacy, and potentially reducing the occurrence of sorafenib-induced resistance through the downregulation of hepatocyte growth factor levels.

Selective inhibitors targeting Fis1/Mid51 protein-protein interactions protect against hypoxia-induced damage in cardiomyocytes

Cardiovascular diseases (CVDs) are the most common non-communicable diseases globally. An estimated 17.9 million people died from CVDs in 2019, representing 32% of all global deaths. Mitochondria play critical roles in cellular metabolic homeostasis, cell survival, and cell death, as well as producing most of the cell's energy. Protein-protein interactions (PPIs) have a significant role in physiological and pathological processes, and aberrant PPIs are associated with various diseases, therefore they are potential drug targets for a broad range of therapeutic areas. Due to their ability to mimic natural interaction motifs and cover relatively larger interaction region, peptides are very promising as PPI inhibitors. To expedite drug discovery, computational approaches are widely used for screening potential lead compounds. Here, we developed peptides that inhibit mitochondrial fission 1 (Fis1)/mitochondrial dynamics 51 kDa (Mid51) PPI to reduce the cellular damage that can lead to various human pathologies, such as CVDs. Based on a rational design approach we developed peptide inhibitors of the Fis1/Mid51 PPI. In silico and in vitro studies were done to evaluate the biological activity and molecular interactions of the peptides. Two peptides, CVP-241 and CVP-242 were identified based on low binding energy and molecular dynamics simulations. These peptides inhibit Fis1/Mid51 PPI (-1324.9 kcal mol-1) in docking calculations (CVP-241, -741.3 kcal mol-1, and CVP-242, -747.4 kcal mol-1), as well as in vitro experimental studies Fis1/Mid51 PPI (KD 0.054 µM) Fis1/Mid51 PPI + CVP-241 (KD 3.43 µM), and Fis1/Mid51 PPI + CVP-242 (KD 44.58 µM). Finally, these peptides have no toxicity to H9c2 cells, and they increase cell viability in cardiomyocytes (H9c2 cells). Consequently, the identified inhibitor peptides could serve as potent molecules in basic research and as leads for therapeutic development.

GLIS1 alleviates cell senescence and renal fibrosis through PGC1-α mediated mitochondrial quality control in kidney aging

Mitochondrial dysfunction is implied as a crucial factor in age-related chronic kidney disease. It is confirmed that Gli-like transcription factor 1 (GLIS1) is involved in age-related renal fibrosis, however, the correlation between mitochondrial disturbances and GLIS1-driven kidney aging are not clearly clarified. Thus, we investigated the regulatory mechanism of GLIS1 in the homeostasis of mitochondrial quality control both in vivo and in vitro. The lower expression of GLIS1 was identified in natural and accelerated kidney aged models, accompanied by the dysfunctions of mitochondrial quality control, including enhanced mitochondrial fission, reduced mitochondrial biogenesis and mitophagy, whereas, GLIS1 could maintain mitochondrial stability by interacting with peroxisome proliferator-activated receptor γ coactivator-1α (PGC1-α). Additionally, the over-expressed GLIS1 inhibited extracellular matrix accumulation and alleviated renal fibrosis while siGLIS1 inhibited PGC1-α transcription, as well as affecting its mitochondria-protective functions. Collectively, we demonstrated that GLIS1 mediated mitochondrial quality control through targeting PGC1-α in kidney aging, which might be a promising therapeutic target for attenuating cell senescence and age-related renal fibrosis.

Targeting mitochondrial shape: at the heart of cardioprotection

There remains an unmet need to identify novel therapeutic strategies capable of protecting the myocardium against the detrimental effects of acute ischemia-reperfusion injury (IRI), to reduce myocardial infarct (MI) size and prevent the onset of heart failure (HF) following acute myocardial infarction (AMI). In this regard, perturbations in mitochondrial morphology with an imbalance in mitochondrial fusion and fission can disrupt mitochondrial metabolism, calcium homeostasis, and reactive oxygen species production, factors which are all known to be critical determinants of cardiomyocyte death following acute myocardial IRI. As such, therapeutic approaches directed at preserving the morphology and functionality of mitochondria may provide an important strategy for cardioprotection. In this article, we provide an overview of the alterations in mitochondrial morphology which occur in response to acute myocardial IRI, and highlight the emerging therapeutic strategies for targeting mitochondrial shape to preserve mitochondrial function which have the future therapeutic potential to improve health outcomes in patients presenting with AMI.

Cardioprotective effects of Moku-boi-to and its impact on AngII-induced cardiomyocyte hypertrophy

Cardiomyocyte hypertrophy, induced by elevated levels of angiotensin II (AngII), plays a crucial role in cardiovascular diseases. Current therapeutic approaches aim to regress cardiac hypertrophy but have limited efficacy. Widely used Japanese Kampo medicines are highly safe and potential therapeutic agents. This study aims to explore the impact and mechanisms by which Moku-boi-to (MBT), a Japanese Kampo medicine, exerts its potential cardioprotective benefits against AngII-induced cardiomyocyte hypertrophy, bridging the knowledge gap and contributing to the development of novel therapeutic strategies. By evaluating the effects of six Japanese Kampo medicines with known cardiovascular efficiency on AngII-induced cardiomyocyte hypertrophy and cell death, we identified MBT as a promising candidate. MBT exhibited preventive effects against AngII-induced cardiomyocyte hypertrophy, cell death and demonstrated improvements in intracellular Ca2+ signaling regulation, ROS production, and mitochondrial function. Unexpectedly, experiments combining MBT with the AT1 receptor antagonist losartan suggested that MBT may target the AT1 receptor. In an isoproterenol-induced heart failure mouse model, MBT treatment demonstrated significant effects on cardiac function and hypertrophy. These findings highlight the cardioprotective potential of MBT through AT1 receptor-mediated mechanisms, offering valuable insights into its efficacy in alleviating AngII-induced dysfunction in cardiomyocytes. The study suggests that MBT holds promise as a safe and effective prophylactic agent for cardiac hypertrophy, providing a deeper understanding of its mechanisms for cardioprotection against AngII-induced dysfunction.

Therapeutic Potential of P110 Peptide: New Insights into Treatment of Alzheimer's Disease

Mitochondrial degeneration in various neurodegenerative diseases, specifically in Alzheimer's disease, involves excessive mitochondrial fission and reduced fusion, leading to cell damage. P110 is a seven-amino acid peptide that restores mitochondrial dynamics by acting as an inhibitor of mitochondrial fission. However, the role of P110 as a neuroprotective agent in AD remains unclear. Therefore, we performed cell culture studies to evaluate the neuroprotective effect of P110 on amyloid-β accumulation and mitochondrial functioning. Human SH-SY5Y neuronal cells were incubated with 1 µM and 10 µM of P110, and Real-Time PCR and Western blot analysis were done to quantify the expression of genes pertaining to AD and neuronal health. Exposure of SH-SY5Y cells to P110 significantly increased APP mRNA levels at 1 µM, while BACE1 mRNA levels were increased at both 1 µM and 10 µM. However, protein levels of both APP and BACE1 were significantly reduced at 10 µM of P110. Further, P110 treatment significantly increased ADAM10 and Klotho protein levels at 10 µM. In addition, P110 exposure significantly increased active mitochondria and reduced ROS in live SH-SY5Y cells at both 1 µM and 10 µM concentrations. Taken together, our results indicate that P110 might be useful in attenuating amyloid-β generation and improving neuronal health by maintaining mitochondrial function in neurons.

Therapeutic Effects of Mesenchymal Stromal Cells Require Mitochondrial Transfer and Quality Control

Due to their beneficial effects in an array of diseases, Mesenchymal Stromal Cells (MSCs) have been the focus of intense preclinical research and clinical implementation for decades. MSCs have multilineage differentiation capacity, support hematopoiesis, secrete pro-regenerative factors and exert immunoregulatory functions promoting homeostasis and the resolution of injury/inflammation. The main effects of MSCs include modulation of immune cells (macrophages, neutrophils, and lymphocytes), secretion of antimicrobial peptides, and transfer of mitochondria (Mt) to injured cells. These actions can be enhanced by priming (i.e., licensing) MSCs prior to exposure to deleterious microenvironments. Preclinical evidence suggests that MSCs can exert therapeutic effects in a variety of pathological states, including cardiac, respiratory, hepatic, renal, and neurological diseases. One of the key emerging beneficial actions of MSCs is the improvement of mitochondrial functions in the injured tissues by enhancing mitochondrial quality control (MQC). Recent advances in the understanding of cellular MQC, including mitochondrial biogenesis, mitophagy, fission, and fusion, helped uncover how MSCs enhance these processes. Specifically, MSCs have been suggested to regulate peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC1α)-dependent biogenesis, Parkin-dependent mitophagy, and Mitofusins (Mfn1/2) or Dynamin Related Protein-1 (Drp1)-mediated fission/fusion. In addition, previous studies also verified mitochondrial transfer from MSCs through tunneling nanotubes and via microvesicular transport. Combined, these effects improve mitochondrial functions, thereby contributing to the resolution of injury and inflammation. Thus, uncovering how MSCs affect MQC opens new therapeutic avenues for organ injury, and the transplantation of MSC-derived mitochondria to injured tissues might represent an attractive new therapeutic approach.

Mitochondrial dysfunction at the crossroad of cardiovascular diseases and cancer

A large body of evidence indicates the existence of a complex pathophysiological relationship between cardiovascular diseases and cancer. Mitochondria are crucial organelles whose optimal activity is determined by quality control systems, which regulate critical cellular events, ranging from intermediary metabolism and calcium signaling to mitochondrial dynamics, cell death and mitophagy. Emerging data indicate that impaired mitochondrial quality control drives myocardial dysfunction occurring in several heart diseases, including cardiac hypertrophy, myocardial infarction, ischaemia/reperfusion damage and metabolic cardiomyopathies. On the other hand, diverse human cancers also dysregulate mitochondrial quality control to promote their initiation and progression, suggesting that modulating mitochondrial homeostasis may represent a promising therapeutic strategy both in cardiology and oncology. In this review, first we briefly introduce the physiological mechanisms underlying the mitochondrial quality control system, and then summarize the current understanding about the impact of dysregulated mitochondrial functions in cardiovascular diseases and cancer. We also discuss key mitochondrial mechanisms underlying the increased risk of cardiovascular complications secondary to the main current anticancer strategies, highlighting the potential of strategies aimed at alleviating mitochondrial impairment-related cardiac dysfunction and tumorigenesis. It is hoped that this summary can provide novel insights into precision medicine approaches to reduce cardiovascular and cancer morbidities and mortalities.

Role of Mitochondria-ER Contact Sites in Mitophagy

Mitochondria are often referred to as the "powerhouse" of the cell. However, this organelle has many more functions than simply satisfying the cells' metabolic needs. Mitochondria are involved in calcium homeostasis and lipid metabolism, and they also regulate apoptotic processes. Many of these functions require contact with the ER, which is mediated by several tether proteins located on the respective organellar surfaces, enabling the formation of mitochondria-ER contact sites (MERCS). Upon damage, mitochondria produce reactive oxygen species (ROS) that can harm the surrounding cell. To circumvent toxicity and to maintain a functional pool of healthy organelles, damaged and excess mitochondria can be targeted for degradation via mitophagy, a form of selective autophagy. Defects in mitochondria-ER tethers and the accumulation of damaged mitochondria are found in several neurodegenerative diseases, including Parkinson's disease and amyotrophic lateral sclerosis, which argues that the interplay between the two organelles is vital for neuronal health. This review provides an overview of the different mechanisms of mitochondrial quality control that are implicated with the different mitochondria-ER tether proteins, and also provides a novel perspective on how MERCS are involved in mediating mitophagy upon mitochondrial damage.

Ischemia/reperfusion-induced MiD51 upregulation recruits Drp1 to mitochondria and contributes to myocardial injury

The translocation of Drp1 from the cytosol to mitochondria leads to Drp1 activation and mitochondrial fission in myocardial ischemia/reperfusion (MI/R). However, the molecular mechanism underlying mitochondrial Drp1 translocation remains poorly understood. Mitochondrial Drp1 recruitment relies on 4 binding partners including MiD49, MiD51, Mff and Fis1. This study was to elucidate which one facilitate mitochondrial Drp1 translocation and its role in MI/R injury. MI/R was induced by ligating the left anterior descending coronary artery for 30 min and subsequent reperfusion for 3 h. Primary neonatal cardiomyocytes were subjected to hypoxia for 2 h and reoxygenation for 4 h. SiRNA or Adeno-associated virus (AAV) expressing shRNA was used to knock down the key binding partner in vitro or in vivo respectively. The expression of MiD51 rather than other binding partners (MiD49, Mff or Fis1) was increased after MI/R. MiD51 knockdown inhibited hypoxia/reoxygenation (H/R) or ischemia/reperfusion (I/R)-induced mitochondrial Drp1 translocation. SiRNA-induced knockdown of MiD51 suppressed mitochondrial oxidative stress, improved mitochondrial function and alleviate cellular injury in H/R cardiomyocytes. AAV-mediated knockdown of MiD51 reduced myocardial injury and improved cardiac function in the I/R hearts, while mitochondrial Drp1 translocation and cardiac function were not affected by MiD51 knockdown in the hearts without I/R. MiD51 is identified as the binding partner that promotes mitochondrial Drp1 translocation and contributes to MI/R injury. Inhibition of MiD51 may be a potential therapeutic target to alleviate MI/R injury.