bims-mitrat 2026-08-16 papers

J Vis Exp. 2026 Jul 21.

Isolation, Purification, and Characterization of Functional Mitochondria Derived from Mouse Skeletal Muscle for Mitochondrial Transplantation.

Lu Zhao, Ningning Da, Jing Wang, Shiping Chang, Lele Shi, Congcong Guan, Lei Tian, Taiqiang Dai.

Mitochondria are essential organelles that regulate energy metabolism, signal transduction, and cellular homeostasis in eukaryotic cells. Mitochondrial dysfunction contributes to the pathogenesis of numerous diseases and has prompted the development of mitochondrial transplantation as a regenerative therapeutic strategy. The successful application of mitochondrial transplantation depends on the availability of highly purified and functionally intact mitochondria. Skeletal muscle is a suitable donor source due to its high mitochondrial content, metabolic activity, and accessibility. This study established a standardized, reproducible protocol for the isolation, purification, and characterization of functional mitochondria from mouse skeletal muscle and evaluated their use in mitochondrial transplantation. The procedure consisted of two major stages. First, mitochondria were isolated from the skeletal muscle of C57BL/6 mice using trypsin digestion followed by differential centrifugation. Second, the isolated mitochondria were characterized to evaluate purity, ultrastructure, and functional activity. Mitochondrial purity was assessed by bicinchoninic acid (BCA) protein quantification and Western blot analysis. Ultrastructural integrity was examined by transmission electron microscopy. Functional activity was evaluated using JC-1 and mitochondrial fluorescent labeling together with measurements of oxygen consumption, ATP production capacity, and respiratory control ratio using a high-resolution respirometry system. The isolated mitochondria exhibited preserved membrane potential, intact ultrastructure, and stable respiratory activity, indicating suitability for downstream functional studies and mitochondrial transplantation applications.

DOI: https://doi.org/10.3791/71551

J Cell Biol. 2026 Sep 07. pii: e202607143. [Epub ahead of print]225(9):

Tunnel traffic: Import stress induces bidirectional mitochondrial transfer between cells.

Konstanze F Winklhofer, Johannes M Herrmann.

Stressed cells can exchange mitochondria through intercellular tunneling nanotubes. In this issue of the JCB, Glover et al. (https://doi.org/10.1083/jcb.202511211) describe two functionally different tunnels: one for exporting dysfunctional mitochondria and another for retrieving respiration-active healthy mitochondria.

DOI: https://doi.org/10.1083/jcb.202607143

J Transl Med. 2026 Aug 07. pii: 1036. [Epub ahead of print]24(1):

Umbilical cord-derived mitochondrial transplantation restores tendon structure and function in a preclinical model of achilles tendinopathy.

Da-Yoon Kim, Mi Jin Kim, Min-Jeong Park, Mina Lim, Eun-Seo Back, Chang-Koo Yun, Seong Hun Kim, Hyuk Nam Kwon, Chaeyoung Lee, Kyunghoon Min, Yong-Soo Choi.

BACKGROUND: Achilles tendinopathy is a degenerative musculoskeletal disorder for which disease-modifying therapies remain limited, largely due to the inability of current interventions to directly restore cellular bioenergetic function. Emerging evidence has identified mitochondrial dysfunction as a central contributor to tendon degeneration, highlighting mitochondria as a potential therapeutic target. Here, we evaluated umbilical cord-derived mitochondria (UC-MT) as a dose-defined, cell-free therapeutic strategy for tendinopathy.
METHODS: UC-MT were isolated from human umbilical cord-derived mesenchymal stem cells and characterized for mitochondrial integrity and bioenergetic activity. Therapeutic efficacy was evaluated in vitro using TNF-α-induced human tenocyte injury models and in vivo in a collagenase-induced rat model of Achilles tendinopathy. Dose-response effects were systematically assessed (5, 10, and 20 µg), and mitochondrial function, metabolic profiles, extracellular matrix remodeling, and functional recovery were analyzed using integrated molecular, histological, and functional assays, including transcriptomic and metabolomic profiling.
RESULTS: UC-MT treatment significantly restored mitochondrial membrane potential, ATP production, and respiratory complex activity in injured tenocytes, accompanied by attenuation of inflammatory signalling. Among the tested doses, 10 µg UC-MT consistently produced the most robust therapeutic effects across mitochondrial, metabolic, and structural outcome measures. In vivo, UC-MT administration improved tendon histoarchitecture, collagen organization, and functional performance, while integrated multi-omics analyses revealed coordinated metabolic reprogramming, including restoration of mitochondrial complex I-linked bioenergetic pathways.
CONCLUSIONS: Taken together, these findings position UC-MT as a dose-defined, cell-free therapeutic modality with translational potential for tendon regeneration. By directly targeting mitochondrial dysfunction, UC-MT restores mitochondrial bioenergetics and supports tendon regeneration in preclinical models of tendinopathy.

Keywords: Achilles tendinopathy; Cell-free regenerative therapy; Mitochondrial bioenergetics; Mitochondrial transplantation; Umbilical cord-derived mitochondria

DOI: https://doi.org/10.1186/s12967-026-08768-w

Bioact Mater. 2027 Jan;67 266-282

Orally activatable membrane fusion-mitochondria hitchhiking on intestinal macrophages for targeted therapy of bacterial meningitis and neuroinflammation.

Xingyou Wang, Xiaoqing Sun, Han Li, Jinyu Zhang, Qiangying Yi, Yao Wu.

Targeting the formidable physiological barriers and neuronal damage refractory to conventional bactericidal agents for bacterial meningitis, we engineered an infection microenvironment-activatable membrane fusion-mitochondrial formulation (Mito@MFL-Glu). This formulation integrates endogenous macrophage hitchhiking, lysosomal exocytosis-driven cargo release, and in situ mitochondrial transplantation. Orally administered, its glucan shell is recognized by microfold cells, enabling macrophage-mediated transport across the blood-brain barrier and chemotactic accumulation at infectious foci. During macrophage uptake, stimulation of the Dectin-1 by the glucan shell sustains intracellular Ca2+ levels. Upon reaching the infectious lesion, the pro-inflammatory microenvironment induces macrophage polarization toward an M1 phenotype, which further elevates intracellular Ca2+ levels. The synergy of these two sequential Ca2+ concentration events cooperatively triggers TFEB-mediated lysosomal exocytosis, resulting in a cargo efflux efficiency of 43.3%. Elevated local reactive oxygen species (ROS) cleave the ROS-responsive linker, detaching the glucan shell and exposing the fusogenic lipid bilayer. This activated layer then directly fuses with damaged neuron and microglial membranes, delivering exogenous mitochondria into the cytosol while bypassing lysosomal degradation and achieving a transplantation efficiency exceeding 36% within 1 h, whereas naked mitochondria show much lower efficiency. Concurrently, the liberated cefotaxime eliminates pathogens, culminating in a synergistic and non-invasive oral closed-loop bactericidal and neuroreparative strategy in a murine meningitis model.

Keywords: Membrane fusion; Meningitis; Mitochondrial transplantation; Neuroinflammation

DOI: https://doi.org/10.1016/j.bioactmat.2026.08.003