bims-mitrat Biomed News
on Mitochondrial transplantation and transfer
Issue of 2025–08–31
nine papers selected by
Gökhan Burçin Kubat, Gulhane Health Sciences Institute



  1. Antioxidants (Basel). 2025 Aug 18. pii: 1008. [Epub ahead of print]14(8):
      Intercellular mitochondrial transfer in the tumor microenvironment (TME) is a paradigm-shifting process that redefines cancer-T cell crosstalk. This review explores its dual nature as both a tumor immune evasion strategy and a promising therapeutic avenue. Crucially, oxidative stress acts as a key regulator, inducing tunneling nanotube (TNT) formation to facilitate this organelle exchange. Tumors exploit this by transferring dysfunctional, reactive oxygen species (ROS) generating mitochondria to T cells to induce senescence while simultaneously hijacking healthy mitochondria from T cells to empower their own metabolism. This directional exchange, quantified by computational tools like mitochondrial-enabled reconstruction of cellular interactions (MERCI), is linked to poor clinical outcomes. Transfer occurs via TNTs, extracellular vesicles, and direct contact. Conversely, the therapeutic transfer of healthy mitochondria from sources like mesenchymal stromal cells can revitalize exhausted T cells, improving chimeric antigen receptor T (CAR-T) cell efficacy. Clinical translation is guided by emerging biomarkers, including circulating mitochondrial DNA (mtDNA), mitochondrial haplogroups, and the tumor mitochondrial transfer (TMT) score. Harnessing this biological axis for next-generation immunotherapies requires overcoming challenges in transfer efficiency and standardization to effectively modulate the tumor redox landscape and immune response.
    Keywords:  MERCI methodology; T cell exhaustion; cancer metabolism; immune evasion; immunotherapy; mitochondrial transfer; oxidative stress; single-cell analysis; tumor microenvironment; tunneling nanotubes
    DOI:  https://doi.org/10.3390/antiox14081008
  2. Cell Prolif. 2025 Aug 27. e70121
      Macrophages and bone marrow mesenchymal stem cells (BMSCs) share a close relationship within the osteoimmune microenvironment. During mechanically induced bone formation, macrophages respond to stimuli and regulate this microenvironment, influencing BMSCs' proliferation and differentiation. However, the underlying mechanisms remain incompletely understood. In our study, we employed a cellular tension system and found that mechanical tension altered mitochondrial dynamics in macrophages, leading to increased mitochondrial fission. Using a macrophage-BMSC direct co-culture system, we demonstrated that macrophages transferred mitochondria to BMSCs, a process enhanced by tension. This enhancement was associated with Drp1-mediated mitochondrial fission, as Drp1 knockdown in macrophages abolished the effect. Additionally, using in vitro co-culture and in vivo tibial injection models, we found that mitochondria-rich extracellular vesicles (Mito-EVs) secreted by mechanically stretched macrophages promoted BMSCs' osteogenesis and enhanced bone formation via the CD200 receptor (CD200R)-CD200 interaction. Our findings reveal a pivotal role for mitochondrial transfer in promoting osteogenesis during mechanotransduction, highlighting a novel mechanism of intercellular communication in bone biology.
    Keywords:  bone marrow mesenchymal stem cell; macrophage; mechanical tension; mitochondria transfer; osteogenesis
    DOI:  https://doi.org/10.1111/cpr.70121
  3. J Thromb Haemost. 2025 Aug 20. pii: S1538-7836(25)00523-9. [Epub ahead of print]
       BACKGROUND: Platelet activation causes the release of extracellular vesicles, of which a small proportion contain respiratory competent mitochondria. Mitochondria are integral for energy production and in the regulation of apoptotic pathways, however the existence of extracellular mitochondria highlights a potential new role in intercellular communication. Indeed, mitochondrial transfer has gained significant research interest in recent years, highlighting mechanisms through which cellular function and metabolism may be augmented.
    OBJECTIVE: To characterise changes in neutrophil function and phenotype that occur because of interactions with mitochondria-positive or mitochondria-negative platelet extracellular vesicles.
    METHODS: Platelet extracellular vesicle subpopulations were separated based on mitochondrial content using cell sorting and subsequently incubated with isolated neutrophils. Alterations in surface receptor repertoire were analysed by flow cytometry, and functional characterisation performed by immunofluorescence, flow cytometry and Seahorse XF metabolic flux assays.
    RESULTS: In this work we demonstrate that platelet extracellular vesicles containing mitochondria interact with and are internalised by neutrophils, subsequently increasing their metabolic capacity. These interactions promote changes in neutrophil receptor repertoire, indicative of enhanced neutrophil activation, adhesion and migration pathways. The internalisation of platelet mitochondria renders neutrophils unable to subsequently engulf bacteria, demonstrating reduced phagocytic capacity, but enhances the formation of neutrophil extracellular traps, both alone and in the presence of additional stimuli.
    CONCLUSIONS: Our findings show that platelet mitochondria released in extracellular vesicles can be transferred into neutrophils, altering their metabolic function and activity. This research highlights an important role for platelet mitochondria as intercellular communicators and modulators of inflammatory and immune responses.
    Keywords:  Extracellular vesicles; NETs; mitochondria; mitochondrial transfer; neutrophils
    DOI:  https://doi.org/10.1016/j.jtha.2025.08.004
  4. Biol Methods Protoc. 2025 ;10(1): bpaf063
      Mitochondrial transplantation is a promising but still experimental strategy for treating ischemic and metabolic disorders. A key barrier to its advancement is the lack of scalable, non-invasive methods for tracking transplanted extracellular mitochondria in vivo. Technetium-99m (Tc-99m) radiopharmaceuticals, widely used in SPECT imaging, may offer a clinically compatible solution. Cryopreserved mitochondria derived from HEK-293 cells were incubated with Tc-99m sestamibi, tetrofosmin, pertechnetate, or control solutions. After brief incubation and washing, mitochondrial pellets were analyzed for retained radioactivity. ATP content was measured to assess metabolic function, and electron microscopy was used to evaluate ultrastructural integrity. Tc-99m sestamibi and tetrofosmin showed labeling efficiencies of 2.74% and 2.68%, respectively. Pertechnetate demonstrated minimal uptake (0.34%). Radiolabeled mitochondria retained ATP production comparable to controls. Electron microscopy showed preserved double membranes and cristae. Controls confirmed assay specificity and viability. To our knowledge, this is the first report of radiolabeling isolated mitochondria with clinically approved Tc-99m agents. This platform supports the development of SPECT-compatible protocols for visualizing viable transplanted mitochondria in recipient tissues.
    Keywords:  SPECT; Technetium-99m; electron microscopy; mitochondria; mitochondrial transplantation; radiopharmaceuticals
    DOI:  https://doi.org/10.1093/biomethods/bpaf063
  5. J Cell Physiol. 2025 Aug;240(8): e70086
      Connexin 43 (Cx43) is a transmembrane protein involved in the assembly of gap junctions (GJs) and hemichannels (HCs), organized structures that allow the transferring of ions and small signaling molecules between cells and/or extracellular environment, thereby contributing to tissue homeostasis intercellular communication. Cx43 has recently been identified within the mitochondria of cells, suggesting that it may have additional functions beyond its canonical role. Most studies of mitochondrial Cx43 (mt-Cx43) have been limited to cells of the cardiovascular system, where it appears to play a role in ATP production, calcium homeostasis, and the response to oxidative stress. However, its functions within the central nervous system (CNS) are not fully understood. Recently, it has been observed that Cx43-forming GJs is one of the key mechanisms that cells use for the transfer of organelles, including mitochondria. Cx43-mediated mitochondrial transfer is crucial in the CNS, supporting cellular homeostasis and neuroprotection under both physiological and pathological conditions. The dual roles of Cx43 in regulating mitochondrial function and in mediating mitochondrial transfer, raise important questions about how it coordinates these mechanisms. Herein, we reviewed recent findings on the importance of Cx43 and mt-Cx43 in the healthy and altered CNS environment, with the aim of shedding light on its potential role in CNS homeostasis and as a therapeutic target in neurological disorder in which Cx43 plays a predominant function.
    Keywords:  gap junction; homeostasis; intercellular communication; metabolism; neurological disorder
    DOI:  https://doi.org/10.1002/jcp.70086
  6. Biomolecules. 2025 Aug 08. pii: 1145. [Epub ahead of print]15(8):
      Mitochondria are central to cellular energy metabolism and play a key role in regulating important physiological processes, including apoptosis and oxidative stress. Mitochondrial quality control has recently garnered significant attention, with the underlying mechanisms traditionally considered to be mitophagy and its dynamics. Various studies have demonstrated that extracellular vesicles are crucial for the transmission of mitochondria and their components. These vesicles effectively transport mitochondria to target cells, facilitating intercellular material exchange and signal transmission, thereby enhancing cellular function and viability. This review explores the mechanisms of mitochondrial transfer through mitochondrial extracellular vesicles (MitoEVs), analyzes the novel roles of MitoEVs in mitochondrial quality control, and discusses their applications in disease treatment. We aim to provide new perspectives for future research and support the development of relevant therapeutic strategies.
    Keywords:  MitoEVs; extracellular vesicle; intercellular material exchange; mitochondria; mitochondrial quality control; signal transmission
    DOI:  https://doi.org/10.3390/biom15081145
  7. Exp Cell Res. 2025 Aug 20. pii: S0014-4827(25)00321-0. [Epub ahead of print]451(2): 114721
      In 1948, before the word 'mitochondrion' gained common parlance in the lexicon of cell biologists, Cyril Darlington published The Plasmagene Theory of the Origin of Cancer without referring to mitochondria per se. Reconsideration of Darlington's theory is warranted today because discoveries about the extraordinary capacities of mitochondria - the organelles that house Darlington's "plasmagenes" - have grown exponentially. If Darlington was right, if intracellular competition between mutant and wild-type mitochondria is the first cause of cancer, it may be the case that a general cure for cancer will include injection of: (A) nanoparticles carrying wild-type mitochondrial genes, and (B) copious amounts of wild-type mitochondria.
    Keywords:  Apoptosis; Cancer; Evolution; Experiment; Heteroplasmic; Homoplasmic; Mitochondria; Mitochondrial transfer; Mitophagy; Reproductive competition; Reversible reaction
    DOI:  https://doi.org/10.1016/j.yexcr.2025.114721
  8. Antioxidants (Basel). 2025 Aug 02. pii: 951. [Epub ahead of print]14(8):
      The administration of isolated mitochondria is a promising strategy for protecting cells from oxidative damage. This study aimed to identify mitochondrial characteristics that contribute to stronger protective effects. We compared two types of mitochondria isolated from C6 cells with similar ATP-producing capacity but differing in outer membrane integrity. To evaluate their stability in extracellular conditions, we examined their behavior in serum. Both types underwent mitochondrial permeability transition to a similar extent; however, under intracellular-like conditions after serum incubation, mitochondria with intact membranes retained more polarized mitochondria. Notably, mitochondria with intact outer membranes were internalized more efficiently than those with damaged membranes. In H9c2 cells, both types of mitochondria similarly increased intracellular ATP levels 1 h after administration under all tested conditions. When co-administered with H2O2, both suppressed oxidative damage to a comparable degree, as indicated by similar H2O2-scavenging activity in solution, comparable intracellular ROS levels, and equivalent preservation of electron transport chain activity. However, at higher H2O2 concentrations, cells treated with mitochondria possessing intact outer membranes exhibited greater survival 24 h after co-administration. Furthermore, when mitochondria were added after H2O2-induced damage and their removal, intact mitochondria conferred superior cell survival compared to damaged ones. These findings suggest that while both mitochondrial types exert comparable antioxidant effects, outer membrane integrity prior to administration plays a critical role in enhancing cell survival under conditions of oxidative stress.
    Keywords:  ROS; cryopreserved mitochondria; mitochondrial administration; oxidative damage
    DOI:  https://doi.org/10.3390/antiox14080951