bims-mitrat Biomed News
on Mitochondrial Transplantation and Transfer
Issue of 2024–10–06
fiveteen papers selected by
Gökhan Burçin Kubat, Gulhane Health Sciences Institute
  1. The Mitochondrial Transplantation: A New Frontier in Plastic Surgery.
  2. ROCK inhibitor enhances mitochondrial transfer via tunneling nanotubes in retinal pigment epithelium.
  3. Mitochondrial transplantation attenuates lipopolysaccharide-induced acute respiratory distress syndrome.
  4. Integrating Mitochondrial Biology into Innovative Cell Therapies for Neurodegenerative Diseases.
  5. Mitochondria: the beating heart of the eukaryotic cell.
  6. Targeting mitochondria with small molecules: A promising strategy for combating Parkinson's disease.
  7. Survival advantage of native and engineered T cells is acquired by mitochondrial transfer from mesenchymal stem cells.
  8. Heme deficiency in skeletal muscle exacerbates sarcopenia and impairs autophagy by reducing AMPK signaling.
  9. Mitochondrial antioxidant SkQ1 attenuates C26 cancer-induced muscle wasting in males and improves muscle contractility in female tumor-bearing mice.
  10. The effect of exogenous mitochondria in enhancing the survival and volume retention of transplanted fat tissue in a nude mice model.
  11. The MyoGravity project to study real microgravity effects on human muscle precursor cells and tissue.
  12. The role of PINK1-Parkin in mitochondrial quality control.
  13. Prenatal and progressive coenzyme Q10 administration to mitigate muscle dysfunction in mitochondrial disease.
  14. Mitochondrial dysfunction, cause or consequence in neurodegenerative diseases?
  15. Longitudinal autophagy profiling of the mammalian brain reveals sustained mitophagy throughout healthy aging.
  1. J Craniofac Surg. 2024 Sep 30.
    The Mitochondrial Transplantation: A New Frontier in Plastic Surgery.
    Haoran Li, Dali Mu.
      Challenges such as difficult wound healing, ischemic necrosis of skin flaps, and skin aging are prevalent in plastic surgery. Previous research has indeed suggested that these challenges in plastic surgery are often linked to cellular energy barriers. As the powerhouses of the cell, mitochondria play a critical role in sustaining cellular vitality and health. Fundamentally, issues like ischemic and hypoxic damage to organs and tissues, as well as aging, stem from mitochondrial dysfunction, which leads to a depletion of cellular energy. Hence, having an adequate number of high-quality, healthy mitochondria is vital for maintaining tissue stability and cell survival. In recent years, there has been preliminary exploration into the protective effects of mitochondrial transplantation against cellular damage in systems such as the nervous, cardiovascular, and respiratory systems. For plastic surgery, mitochondrial transplantation is an extremely advanced research topic. This review focuses on the novel applications and future prospects of mitochondrial transplantation in plastic surgery, providing insights for clinicians and researchers, and offering guidance to patients seeking innovative and effective treatment options.
    DOI:  https://doi.org/10.1097/SCS.0000000000010706
  2. Theranostics. 2024 ;14(15): 5762-5777
    ROCK inhibitor enhances mitochondrial transfer via tunneling nanotubes in retinal pigment epithelium.
    Jing Yuan, Fangxuan Chen, Dan Jiang, Zehua Xu, Hang Zhang, Zi-Bing Jin.
      Rationale: Tunnel nanotube (TNT)-mediated mitochondrial transport is crucial for the development and maintenance of multicellular organisms. Despite numerous studies highlighting the significance of this process in both physiological and pathological contexts, knowledge of the underlying mechanisms is still limited. This research focused on the role of the ROCK inhibitor Y-27632 in modulating TNT formation and mitochondrial transport in retinal pigment epithelial (RPE) cells. Methods: Two types of ARPE19 cells (a retinal pigment epithelial cell line) with distinct mitochondrial fluorescently labeled, were co-cultured and treated with ROCK inhibitor Y-27632. The formation of nanotubes and transport of mitochondria were assessed through cytoskeletal staining and live cell imaging. Mitochondrial dysfunction was induced by light damage to establish a model, while mitochondrial function was evaluated through measurement of oxygen consumption rate. The effects of Y-27632 on cytoskeletal and mitochondrial dynamics were further elucidated through detailed analysis. Results: Y-27632 treatment led to an increase in nanotube formation and enhanced mitochondrial transfer among ARPE19 cells, even following exposure to light-induced damage. Our analysis of cytoskeletal and mitochondrial distribution changes suggests that Y-27632 promotes nanotube-mediated mitochondrial transport by influencing cytoskeletal remodeling and mitochondrial movement. Conclusions: These results suggest that Y-27632 has the ability to enhance mitochondrial transfer via tunneling nanotubes in retinal pigment epithelium, and similarly predict that ROCK inhibitor can fulfill its therapeutic potential through promoting mitochondrial transport in the retinal pigment epithelium in the future.
    Keywords:  ARPE19; Y-27632; cytoskeletal remodeling; light damage; mitochondrial transfer; nanotubes
    DOI:  https://doi.org/10.7150/thno.96508
  3. BMC Pulm Med. 2024 Sep 27. 24(1): 477
    Mitochondrial transplantation attenuates lipopolysaccharide-induced acute respiratory distress syndrome.
    Seo-Eun Lee, In-Hyeon Kim, Young Cheol Kang, Yujin Kim, Shin-Hye Yu, Jeong Seon Yeo, Iksun Kwon, Jun Hyeok Lim, Je-Hein Kim, Kyuboem Han, Sung-Hwan Kim, Chun-Hyung Kim.
       BACKGROUND: The mitochondria are essential organelles not only providing cellular energy in the form of ATP, but also regulating the inflammatory response and the cell death program. Mitochondrial dysfunction has been associated with various human diseases, including metabolic syndromes as well as inflammatory and neurodegenerative diseases. Acute respiratory distress syndrome (ARDS) is an acute pulmonary disorder characterized by uncontrolled alveolar inflammation, apoptotic lung epithelial/endothelial cells, and pulmonary edema. Despite the high mortality of ARDS, an effective pharmacotherapy to treat this disease has not been established yet. Therefore, identifying a novel targeted therapy for ARDS is important. Recently, exogenous mitochondrial transplantation was reported to be beneficial for treating mitochondrial dysfunction. The current study aimed to investigate the therapeutic effect of mitochondrial transplantation on ARDS in vitro and in vivo.
    METHODS: Mitochondria were isolated from human stem cells. For in vitro efficacy of mitochondrial transplantation on the inflammation and cell death, murine alveolar macrophages MH-S and human pulmonary microvascular endothelial cells HPMECs were exposed to LPS, respectively. The ARDS mice model established by a single intratracheal instillation of LPS was used for in vivo efficacy of intravenously treated mitochondria.
    RESULTS: Our results showed that the mitochondria isolated from human stem cells exhibited an anti-inflammatory effect against alveolar macrophages and an anti-apoptotic effect against the alveolar epithelial cells. Furthermore, intravenous mitochondrial treatment was associated with the attenuation of lung injury in the LPS-induced ARDS mice.
    CONCLUSION: Dual effects of mitochondria on anti-inflammation and anti-apoptosis support the potential of mitochondrial transplantation as a novel therapeutic strategy for ARDS.
    Keywords:  Acute respiratory distress syndrome (ARDS); Anti-inflammation; Antiapoptosis; Lipopolysaccharide; Mitochondria; Stem cell; Transplantation
    DOI:  https://doi.org/10.1186/s12890-024-03304-2
  4. Brain Sci. 2024 Sep 05. pii: 899. [Epub ahead of print]14(9):
    Integrating Mitochondrial Biology into Innovative Cell Therapies for Neurodegenerative Diseases.
    Adaleiz Ore, James M Angelastro, Cecilia Giulivi.
      The role of mitochondria in neurodegenerative diseases is crucial, and recent developments have highlighted its significance in cell therapy. Mitochondrial dysfunction has been implicated in various neurodegenerative disorders, including Alzheimer's, Parkinson's, amyotrophic lateral sclerosis, and Huntington's diseases. Understanding the impact of mitochondrial biology on these conditions can provide valuable insights for developing targeted cell therapies. This mini-review refocuses on mitochondria and emphasizes the potential of therapies leveraging mesenchymal stem cells, embryonic stem cells, induced pluripotent stem cells, stem cell-derived secretions, and extracellular vesicles. Mesenchymal stem cell-mediated mitochondria transfer is highlighted for restoring mitochondrial health in cells with dysfunctional mitochondria. Additionally, attention is paid to gene-editing techniques such as mito-CRISPR, mitoTALENs, mito-ZNFs, and DdCBEs to ensure the safety and efficacy of stem cell treatments. Challenges and future directions are also discussed, including the possible tumorigenic effects of stem cells, off-target effects, disease targeting, immune rejection, and ethical issues.
    Keywords:  cell therapy; ethical concerns; exosomes; extracellular vesicles; mitochondrial dysfunction; mitochondrial medicine; neurodegenerative diseases; stem cells
    DOI:  https://doi.org/10.3390/brainsci14090899
  5. FEBS Open Bio. 2024 Oct;14(10): 1588-1590
    Mitochondria: the beating heart of the eukaryotic cell.
    Johannes M Herrmann.
      Mitochondria are essential organelles of eukaryotic cells. They consist of hundreds of proteins, which are synthesized in the cytosol and imported into mitochondria via different targeting routes. In addition, a small number of proteins are encoded by the organellar genome and synthesized by mitochondrial ribosomes. In this 'In the Limelight' special issue of FEBS Open Bio, five review articles describe these different biogenesis routes of mitochondrial proteins and provide a comprehensive overview of the structures and mechanisms by which mitochondrial proteins are synthesized and transported to their respective location within the organelle. These reviews, written by leading experts, provide a general overview, but also highlight current developments in the field of mitochondrial biogenesis.
    DOI:  https://doi.org/10.1002/2211-5463.13884
  6. Mitochondrion. 2024 Sep 30. pii: S1567-7249(24)00129-6. [Epub ahead of print] 101971
    Targeting mitochondria with small molecules: A promising strategy for combating Parkinson's disease.
    Chinmay Pal.
      Parkinson's disease (PD), a neurodegenerative disorder, is one of the most significant challenges confronting modern societies, affecting millions of patients globally each year. The pathophysiology of PD is significantly influenced by mitochondrial dysfunction, as evident by the contribution of altered mitochondrial dynamics, bioenergetics, and increased oxidative stress to neuronal death. This review examines the potential use of small molecules that target mitochondria as a therapeutic approach for treating PD. Progress in mitochondrial biology has revealed various mitochondrial targets that can be modulated to restore function and mitigate neurodegeneration. Small molecules that promote mitochondrial biogenesis, enhance mitochondrial dynamics, decrease oxidative stress, and prevent the opening of the mitochondrial permeability transition pore (mPTP) have shown promise in preclinical models. Additionally, targeting mitochondrial quality control mechanisms, such as mitophagy, provides another therapeutic approach. This review explores recent research on small molecules targeting mitochondria, examines their mechanisms of action, and assesses their potential efficacy and safety profiles. By highlighting the most promising candidates and addressing the challenges and future directions in this field, this review aims to offer a comprehensive overview of current and future prospects for mitochondrial-targeted therapies in PD. Ultimately, treating mitochondrial dysfunction holds significant promise for developing disease-modifying PD medications, giving patients hope for better outcomes and improved quality of life.
    Keywords:  Mitochondrial dysfunction; Oxidative Stress; Parkinson’s disease; Reactive oxygen species; Small molecule
    DOI:  https://doi.org/10.1016/j.mito.2024.101971
  7. J Transl Med. 2024 Sep 27. 22(1): 868
    Survival advantage of native and engineered T cells is acquired by mitochondrial transfer from mesenchymal stem cells.
    Angela C Court, Eliseo Parra-Crisóstomo, Pablo Castro-Córdova, Luiza Abdo, Emmanuel Arthur Albuquerque Aragão, Rocío Lorca, Fernando E Figueroa, Martín Hernán Bonamino, Maroun Khoury.
       BACKGROUND: Apoptosis, a form of programmed cell death, is critical for the development and homeostasis of the immune system. Chimeric antigen receptor T (CAR-T) cell therapy, approved for hematologic cancers, retains several limitations and challenges associated with ex vivo manipulation, including CAR T-cell susceptibility to apoptosis. Therefore, strategies to improve T-cell survival and persistence are required. Mesenchymal stem/stromal cells (MSCs) exhibit immunoregulatory and tissue-restoring potential. We have previously shown that the transfer of umbilical cord MSC (UC-MSC)-derived mitochondrial (MitoT) prompts the genetic reprogramming of CD3+ T cells towards a Treg cell lineage. The potency of T cells plays an important role in effective immunotherapy, underscoring the need for improving their metabolic fitness. In the present work, we evaluate the effect of MitoT on apoptotis of native T lymphocytes and engineered CAR-T cells.
    METHODS: We used a cell-free approach using artificial MitoT (Mitoception) of UC-MSC derived MT to peripheral blood mononuclear cells (PBMCs) followed by RNA-seq analysis of CD3+ MitoTpos and MitoTneg sorted cells. Target cell apoptosis was induced with Staurosporine (STS), and cell viability was evaluated with Annexin V/7AAD and TUNEL assays. Changes in apoptotic regulators were assessed by flow cytometry, western blot, and qRT-PCR. The effect of MitoT on 19BBz CAR T-cell apoptosis in response to electroporation with a non-viral transposon-based vector was assessed with Annexin V/7AAD.
    RESULTS: Gene expression related to apoptosis, cell death and/or responses to different stimuli was modified in CD3+ T cells after Mitoception. CD3+MitoTpos cells were resistant to STS-induced apoptosis compared to MitoTneg cells, showing a decreased percentage in apoptotic T cells as well as in TUNEL+ cells. Additionally, MitoT prevented the STS-induced collapse of the mitochondrial membrane potential (MMP) levels, decreased caspase-3 cleavage, increased BCL2 transcript levels and BCL-2-related BARD1 expression in FACS-sorted CD3+ T cells. Furthermore, UC-MSC-derived MitoT reduced both early and late apoptosis in CAR-T cells following electroporation, and exhibited an increasing trend in cytotoxic activity levels.
    CONCLUSIONS: Artificial MitoT prevents STS-induced apoptosis of human CD3+ T cells by interfering with the caspase pathway. Furthermore, we observed that MitoT confers protection to apoptosis induced by electroporation in MitoTpos CAR T-engineered cells, potentially improving their metabolic fitness and resistance to environmental stress. These results widen the physiological perspective of organelle-based therapies in immune conditions while offering potential avenues to enhance CAR-T treatment outcomes where their viability is compromised.
    Keywords:  Chimeric antigen receptor T (CAR-T) cells; Induced-apoptosis; Mesenchymal stromal/stem cells; Mitochondria transfer
    DOI:  https://doi.org/10.1186/s12967-024-05627-4
  8. Sci Rep. 2024 09 27. 14(1): 22147
    Heme deficiency in skeletal muscle exacerbates sarcopenia and impairs autophagy by reducing AMPK signaling.
    Takeru Akabane, Hiromori Sagae, Koen van Wijk, Shinichi Saitoh, Tomohiro Kimura, Satoshi Okano, Ken Kodama, Kiwamu Takahashi, Motowo Nakajima, Tohru Tanaka, Michiaki Takagi, Osamu Nakajima.
      Heme serves as a prosthetic group in hemoproteins, including subunits of the mammalian mitochondrial electron transfer chain. The first enzyme in vertebrate heme biosynthesis, 5-aminolevulinic acid synthase 1 (ALAS1), is ubiquitously expressed and essential for producing 5-aminolevulinic acid (ALA). We previously showed that Alas1 heterozygous mice at 20-35 weeks (aged-A1+/-s) manifested impaired glucose metabolism, mitochondrial malformation in skeletal muscle, and reduced exercise tolerance, potentially linked to autophagy dysfunction. In this study, we investigated autophagy in A1+/-s and a sarcopenic phenotype in A1+/-s at 75-95 weeks (senile-A1+/-s). Senile-A1+/-s exhibited significantly reduced body and gastrocnemius muscle weight, and muscle strength, indicating an accelerated sarcopenic phenotype. Decreases in total LC3 and LC3-II protein and Map1lc3a mRNA levels were observed in aged-A1+/-s under fasting conditions and in Alas1 knockdown myocyte-differentiated C2C12 cells (A1KD-C2C12s) cultured in high- or low-glucose medium. ALA treatment largely reversed these declines. Reduced AMP-activated protein kinase (AMPK) signaling was associated with decreased autophagy in aged-A1+/-s and A1KD-C2C12s. AMPK modulation using AICAR (activator) and dorsomorphin (inhibitor) affected LC3 protein levels in an AMPK-dependent manner. Our findings suggest that heme deficiency contributes to accelerated sarcopenia-like defects and reduced autophagy in skeletal muscle, primarily due to decreased AMPK signaling.
    Keywords:  5-aminolevulinic acid; 5-aminolevulinic acid synthase 1 (ALAS1); Autophagy; Heme; Sarcopenia; Skeletal muscle
    DOI:  https://doi.org/10.1038/s41598-024-73049-9
  9. Am J Physiol Cell Physiol. 2024 Sep 30.
    Mitochondrial antioxidant SkQ1 attenuates C26 cancer-induced muscle wasting in males and improves muscle contractility in female tumor-bearing mice.
    Stavroula Tsitkanou, Francielly Morena da Silva, Ana Regina Cabrera, Eleanor R Schrems, Ruqaiza Muhyudin, Pieter J Koopmans, Sabin Khadgi, Seongkyun Lim, Luca J Delfinis, Tyrone A Washington, Kevin A Murach, Christopher G R Perry, Nicholas P Greene.
      Mitochondrial dysfunction is a hallmark of cancer cachexia (CC). Mitochondrial reactive oxygen species (ROS) are elevated in muscle shortly after tumor onset. Targeting mitochondrial ROS may be a viable option to prevent CC. The aim of this study was to evaluate the efficacy of a mitochondria-targeted antioxidant, SkQ1, to mitigate CC in both biological sexes. Male and female Balb/c mice were injected bilaterally with colon 26 adenocarcinoma (C26) cells (total 1x106 cells) or PBS (equal volume control). SkQ1 was dissolved in drinking water (~250 nmol/kg body weight/day) and administered to mice beginning seven days following tumor induction, while control groups consumed normal drinking water. In vivo muscle contractility of dorsiflexors, deuterium oxide-based protein synthesis, mitochondrial respiration and mRNA content of mitochondrial, protein turnover and calcium channel-related markers were assessed at endpoint (25 days following tumor induction). Two-way ANOVAs, followed by Tukey's post-hoc test when interactions were significant (p≤0.05), were performed. SkQ1 attenuated cancer-induced atrophy, promoted protein synthesis and abated Redd1 and Atrogin induction in gastrocnemius of C26 male mice. In female mice, SkQ1 decreased muscle mass and increased catabolic signaling in the plantaris of tumor-bearing mice, as well as reduced mitochondrial oxygen consumption, regardless of tumor. However, in females SkQ1 enhanced muscle contractility of the dorsiflexors with concurrent induction of Ryr1, Serca1 and Serca2a in TA. In conclusion, the mitochondria-targeted antioxidant SkQ1 may attenuate CC-induced muscle loss in males, while improving muscle contractile function in tumor-bearing female mice, suggesting sexual dimorphism in the effects of this mitochondrial therapy in CC.
    Keywords:  cancer cachexia; protein turnover; reactive oxygen species; sexual dimorphism; skeletal muscle
    DOI:  https://doi.org/10.1152/ajpcell.00497.2024
  10. Stem Cell Res Ther. 2024 Sep 27. 15(1): 321
    The effect of exogenous mitochondria in enhancing the survival and volume retention of transplanted fat tissue in a nude mice model.
    Haoran Li, Zhengyao Li, Xiaoyu Zhang, Yan Lin, Tongtong Zhang, Leijuan Gan, Dali Mu.
       BACKGROUND: Despite the pivotal role of fat grafting in plastic, reconstructive, and aesthetic surgery, inconsistent survival rates of transplanted adipose tissue, primarily due to early ischemic and hypoxic insults, remain a significant challenge. The infusion of healthy mitochondria has emerged as a promising intervention to support tissue recovery from ischemic, hypoxic, and other types of damages across various organ systems.
    OBJECTIVES: This study aims to evaluate the impact of supplementing human adipose tissue grafts with healthy exogenous mitochondria on their volume and mass retention rates when transplanted into the subcutaneous layers of nude mice. This approach seeks to improve and optimize fat grafting techniques.
    METHODS: Human adipose tissues were preconditioned with exogenous mitochondria (10 µg/mL), a combination of exogenous mitochondria and the inhibitor Dyngo-4a, Dyngo-4a alone, or PBS, and then transplanted into the subcutaneous tissue of 24 nude mice. Samples were harvested at 1 and 3 months post-transplantation for analysis of mass and volume retention. The structural morphology and integrity of the adipose tissues were assessed using Hematoxylin and Eosin (H&E) staining.
    RESULTS: Mitochondrial preconditioning significantly enhanced the retention of mass and volume in fat grafts, demonstrating superior structural morphology and integrity compared to the control group.
    CONCLUSIONS: This study highlights the potential of exogenous mitochondrial augmentation in fat transplantation to significantly improve fat graft survival, thereby optimizing the success of fat grafting procedures.
    Keywords:  Exogenous mitochondria; Fat grafting; Hypoxic injury; Mitochondria transplantation
    DOI:  https://doi.org/10.1186/s13287-024-03938-3
  11. NPJ Microgravity. 2024 Oct 03. 10(1): 92
    The MyoGravity project to study real microgravity effects on human muscle precursor cells and tissue.
    Ester Sara Di Filippo, Sara Chiappalupi, Stefano Falone, Vincenza Dolo, Fernanda Amicarelli, Silvia Marchianò, Adriana Carino, Gabriele Mascetti, Giovanni Valentini, Sara Piccirillo, Michele Balsamo, Marco Vukich, Stefano Fiorucci, Guglielmo Sorci, Stefania Fulle.
      Microgravity (µG) experienced during space flights promotes adaptation in several astronauts' organs and tissues, with skeletal muscles being the most affected. In response to reduced gravitational loading, muscles (especially, lower limb and antigravity muscles) undergo progressive mass loss and alteration in metabolism, myofiber size, and composition. Skeletal muscle precursor cells (MPCs), also known as satellite cells, are responsible for the growth and maintenance of muscle mass in adult life as well as for muscle regeneration following damage and may have a major role in µG-induced muscle wasting. Despite the great relevance for astronaut health, very few data are available about the effects of real µG on human muscles. Based on the MyoGravity project, this study aimed to analyze: (i) the cellular and transcriptional alterations induced by real µG in human MPCs (huMPCs) and (ii) the response of human skeletal muscle to normal gravitational loading after prolonged exposure to µG. We evaluated the transcriptomic changes induced by µG on board the International Space Station (ISS) in differentiating huMPCs isolated from Vastus lateralis muscle biopsies of a pre-flight astronaut and an age- and sex-matched volunteer, in comparison with the same cells cultured on the ground in standard gravity (1×g) conditions. We found that huMPCs differentiated under real µG conditions showed: (i) upregulation of genes related to cell adhesion, plasma membrane components, and ion transport; (ii) strong downregulation of genes related to the muscle contraction machinery and sarcomere organization; and (iii) downregulation of muscle-specific microRNAs (myomiRs). Moreover, we had the unique opportunity to analyze huMPCs and skeletal muscle tissue of the same astronaut before and 30 h after a long-duration space flight on board the ISS. Prolonged exposure to real µG strongly affected the biology and functionality of the astronaut's satellite cells, which showed a dramatic reduction of responsiveness to activating stimuli and proliferation rate, morphological changes, and almost inability to fuse into myotubes. RNA-Seq analysis of post- vs. pre-flight muscle tissue showed that genes involved in muscle structure and remodeling are promptly activated after landing following a long-duration space mission. Conversely, genes involved in the myelination process or synapse and neuromuscular junction organization appeared downregulated. Although we have investigated only one astronaut, these results point to a prompt readaptation of the skeletal muscle mechanical components to the normal gravitational loading, but the inability to rapidly recover the physiological muscle myelination/innervation pattern after landing from a long-duration space flight. Together with the persistent functional deficit observed in the astronaut's satellite cells after prolonged exposure to real µG, these results lead us to hypothesize that a condition of inefficient regeneration is likely to occur in the muscles of post-flight astronauts following damage.
    DOI:  https://doi.org/10.1038/s41526-024-00432-1
  12. Nat Cell Biol. 2024 Oct 02.
    The role of PINK1-Parkin in mitochondrial quality control.
    Derek P Narendra, Richard J Youle.
      Mitophagy mediated by the recessive Parkinson's disease genes PINK1 and Parkin responds to mitochondrial damage to preserve mitochondrial function. In the pathway, PINK1 is the damage sensor, probing the integrity of the mitochondrial import pathway, and activating Parkin when import is blocked. Parkin is the effector, selectively marking damaged mitochondria with ubiquitin for mitophagy and other quality-control processes. This selective mitochondrial quality-control pathway may be especially critical for dopamine neurons affected in Parkinson's disease, in which the mitochondrial network is widely distributed throughout a highly branched axonal arbor. Here we review the current understanding of the role of PINK1-Parkin in the quality control of mitophagy, including sensing of mitochondrial distress by PINK1, activation of Parkin by PINK1 to induce mitophagy, and the physiological relevance of the PINK1-Parkin pathway.
    DOI:  https://doi.org/10.1038/s41556-024-01513-9
  13. J Cachexia Sarcopenia Muscle. 2024 Oct 02.
    Prenatal and progressive coenzyme Q10 administration to mitigate muscle dysfunction in mitochondrial disease.
    Juan Diego Hernández-Camacho, Cristina Vicente-García, Lorena Ardila-García, Ana Padilla-Campos, Guillermo López-Lluch, Carlos Santos-Ocaña, Peter S Zammit, Jaime J Carvajal, Plácido Navas, Daniel J M Fernández-Ayala.
       BACKGROUND: ADCK genes encode aarF domain-containing mitochondrial kinases involved in coenzyme Q (CoQ) biosynthesis and regulation. Haploinsufficiency of ADCK2 in humans leads to adult-onset physical incapacity with reduced mitochondrial CoQ levels in skeletal muscle, resulting in mitochondrial myopathy and alterations in fatty acid β-oxidation. The sole current treatment for CoQ deficiencies is oral administration of CoQ10, which causes only partial recovery with postnatal treatment, underscoring the importance of early diagnosis for successful intervention.
    METHODS: We used Adck2 heterozygous mice to examine the influence of this gene on muscle structure, function and regeneration throughout development, growth and ageing. This investigation involved techniques including immunohistochemistry, analysis of CoQ levels, mitochondrial respiratory content, muscle transcriptome analysis and functional tests.
    RESULTS: We demonstrated that Adck2 heterozygous mice exhibit defects from embryonic development, particularly in skeletal muscle (1102 genes deregulated). Adck2 heterozygous embryos were 7% smaller in size and displayed signs of delayed development. Prenatal administration of CoQ10 could mitigate these embryonic defects. Heterozygous Adck2 mice also showed a decrease in myogenic cell differentiation, with more severe consequences in 'aged' mice (41.63% smaller) (P < 0.01). Consequently, heterozygous Adck2 mice displayed accelerated muscle wasting associated with ageing in muscle structure (P < 0.05), muscle function (less grip strength capacity) (P < 0.001) and muscle mitochondrial respiration (P < 0.001). Furthermore, progressive CoQ10 administration conferred protective effects on mitochondrial function (P < 0.0001) and skeletal muscle (P < 0.05).
    CONCLUSIONS: Our work uncovered novel aspects of CoQ deficiencies, revealing defects during embryonic development in mammals for the first time. Additionally, we identified the gradual establishment and progression of the deleterious Adck2 mouse phenotype. Importantly, CoQ10 supplementation demonstrated a protective effect when initiated during development.
    Keywords:  ageing; coenzyme Q; development; mitochondria; satellite cell; skeletal muscle
    DOI:  https://doi.org/10.1002/jcsm.13574
  14. Bioessays. 2024 Oct 04. e2400023
    Mitochondrial dysfunction, cause or consequence in neurodegenerative diseases?
    Zoë P Van Acker, Thomas Leroy, Wim Annaert.
      Neurodegenerative diseases encompass a spectrum of conditions characterized by the gradual deterioration of neurons in the central and peripheral nervous system. While their origins are multifaceted, emerging data underscore the pivotal role of impaired mitochondrial functions and endolysosomal homeostasis to the onset and progression of pathology. This article explores whether mitochondrial dysfunctions act as causal factors or are intricately linked to the decline in endolysosomal function. As research delves deeper into the genetics of neurodegenerative diseases, an increasing number of risk loci and genes associated with the regulation of endolysosomal and autophagy functions are being identified, arguing for a downstream impact on mitochondrial health. Our hypothesis centers on the notion that disturbances in endolysosomal processes may propagate to other organelles, including mitochondria, through disrupted inter-organellar communication. We discuss these views in the context of major neurodegenerative diseases including Alzheimer's and Parkinson's diseases, and their relevance to potential therapeutic avenues.
    Keywords:  lysosomal homeostasis; mitochondrial homeostasis; neurodegenerative diseases
    DOI:  https://doi.org/10.1002/bies.202400023
  15. EMBO J. 2024 Oct 04.
    Longitudinal autophagy profiling of the mammalian brain reveals sustained mitophagy throughout healthy aging.
    Anna Rappe, Helena A Vihinen, Fumi Suomi, Antti J Hassinen, Homa Ehsan, Eija S Jokitalo, Thomas G McWilliams.
      Mitophagy neutralizes mitochondrial damage, thereby preventing cellular dysfunction and apoptosis. Defects in mitophagy have been strongly implicated in age-related neurodegenerative disorders such as Parkinson's and Alzheimer's disease. While mitophagy decreases throughout the lifespan of short-lived model organisms, it remains unknown whether such a decline occurs in the aging mammalian brain-a question of fundamental importance for understanding cell type- and region-specific susceptibility to neurodegeneration. Here, we define the longitudinal dynamics of basal mitophagy and macroautophagy across neuronal and non-neuronal cell types within the intact aging mouse brain in vivo. Quantitative profiling of reporter mouse cohorts from young to geriatric ages reveals cell- and tissue-specific alterations in mitophagy and macroautophagy between distinct subregions and cell populations, including dopaminergic neurons, cerebellar Purkinje cells, astrocytes, microglia and interneurons. We also find that healthy aging is hallmarked by the dynamic accumulation of differentially acidified lysosomes in several neural cell subsets. Our findings argue against any widespread age-related decline in mitophagic activity, instead demonstrating dynamic fluctuations in mitophagy across the aging trajectory, with strong implications for ongoing theragnostic development.
    Keywords:  Aging; Autophagy; Brain; Mitochondria; Mitophagy
    DOI:  https://doi.org/10.1038/s44318-024-00241-y
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