title: Direct human mitochondrial transfer: a novel concept based on the endosymbiotic theory.
abstract: Mitochondria play an essential role in eukaryotes, and mitochondrial dysfunction is implicated in several diseases. Therefore, intercellular mitochondrial transfer has been proposed as a mechanism for cell-based therapy. In addition, internalization of isolated mitochondria cells by simple coincubation was reported to improve mitochondrial function in the recipient cells. However, substantial evidence for internalization of isolated mitochondria is still lacking, and its precise mechanism remains elusive. We tested whether enriched mitochondria can be internalized into cultured human cells by simple coincubation using fluorescence microscopy and flow cytometry. Mitochondria were isolated from endometrial gland-derived mesenchymal cells (EMCs) or EMCs stably expressing mitochondrial-targeted red fluorescent protein (EMCs-DsRed-mito), and enriched by anti-mitochondrial antibody-conjugated microbeads. They were coincubated with isogeneic EMCs stably expressing green fluorescent protein (GFP). Live fluorescence imaging clearly showed that DsRed-labeled mitochondria accumulated in the cytoplasm of EMCs stably expressing GFP around the nucleus. Flow cytometry confirmed the presence of a distinct population of GFP and DsRed double-positive cells within the recipient cells. In addition, transfer efficiency depended on mitochondrial concentration, indicating that human cells may possess the inherent ability to internalize mitochondria. Therefore, this study supports the application of direct transfer of isogeneic mitochondria as a novel approach for the treatment of diseases associated with mitochondrial dysfunction.
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kitani
authors.affiliation: Department of Regenerative Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: D
authors.initials: D
authors.lastname: Kami
authors.affiliation: Department of Regenerative Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kawasaki
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Nakata
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Matoba
authors.affiliation: Department of Regenerative Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan. Electronic address: gojos@koto.kpu-m.ac.jp.
authors.forename: S
authors.initials: S
authors.lastname: Gojo
mesh_terms: D002460:Cell Line; D004717:Endometrium / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D005260:Female; D005434:Flow Cytometry; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D006801:Humans; D008164:Luminescent Proteins / Q000096:biosynthesis / Q000235:genetics; D008648:Mesoderm / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism / Q000637:transplantation* / Q000648:ultrastructure; D014162:Transfection
chemical_list: D008164:Luminescent Proteins; C413663:fluorescent protein 583; D049452:Green Fluorescent Proteins