Internalization of Isolated Functional Mitochondria: Involvement of Macropinocytosis

J Cell Mol Med. 2014 Aug;18(8):1694-703. doi: 10.1111/jcmm.12316. Epub 2014 Jun 9.

Abstract

In eukaryotic cells, mitochondrial dysfunction is associated with a variety of human diseases. Delivery of exogenous functional mitochondria into damaged cells has been proposed as a mechanism of cell transplant and physiological repair for damaged tissue. We here demonstrated that isolated mitochondria can be transferred into homogeneic and xenogeneic cells by simple co-incubation using genetically labelled mitochondria, and elucidated the mechanism and the effect of direct mitochondrial transfer. Intracellular localization of exogenous mitochondria was confirmed by PCR, real-time PCR, live fluorescence imaging, three-dimensional reconstruction imaging, continuous time-lapse microscopic observation, flow cytometric analysis and immunoelectron microscopy. Isolated homogeneic mitochondria were transferred into human uterine endometrial gland-derived mesenchymal cells in a dose-dependent manner. Moreover, mitochondrial transfer rescued the mitochondrial respiratory function and improved the cellular viability in mitochondrial DNA-depleted cells and these effects lasted several days. Finally, we discovered that mitochondrial internalization involves macropinocytosis. In conclusion, these data support direct transfer of exogenous mitochondria as a promising approach for the treatment of various diseases.

Keywords: macropinocytosis; mitochondrial transfer; rho0 cells.

MeSH terms

  • Animals
  • Cell Survival
  • Cells, Cultured
  • Cervix Uteri / cytology
  • Cervix Uteri / physiology*
  • DNA, Mitochondrial / genetics
  • Endometrium / cytology
  • Endometrium / physiology*
  • Energy Metabolism
  • Female
  • Flow Cytometry
  • Humans
  • Imaging, Three-Dimensional
  • Mesoderm / cytology
  • Mesoderm / physiology*
  • Microscopy, Confocal
  • Microscopy, Immunoelectron
  • Mitochondria / metabolism
  • Mitochondria / transplantation*
  • Mitochondria / ultrastructure
  • Myocytes, Cardiac / cytology
  • Myocytes, Cardiac / physiology*
  • Pinocytosis*
  • Rats
  • Real-Time Polymerase Chain Reaction

Substances

  • DNA, Mitochondrial