Mitochondria, known as the “powerhouse of cells,” are critical to human health. Dysfunction of these organelles underlies a range of major diseases, including neurodegenerative disorders, diabetes, hepatic diseases, ophthalmic conditions, and aging. Mitochondrial diseases, a unique category of genetic disorders, can stem from defects in nuclear genes that encode mitochondrial proteins or mutations in mitochondrial DNA (mtDNA).
Beyond symptomatic management, effective treatment for mitochondrial diseases remains a global challenge. While mitochondrial transplantation—delivering healthy mitochondria to compensate for cellular defects and reduce mtDNA mutation load—is widely recognized as a promising therapeutic direction, achieving safe and efficient transplantation has long been an unsolved problem.
To address this challenge, a research team from the Guangzhou Institutes of Biomedicine and Health of the Chinese Academy of Sciences has developed a novel strategy. It involves encapsulating healthy mitochondria within vesicles derived from red blood cell membranes. Their findings were recently published in the journal Cell.
These “mitochondrial capsules,” approximately one micrometer in diameter, protect mitochondria during delivery and facilitate their efficient entry into target cells, achieving an estimated 80% transplantation efficiency in cultured cells. Donor mitochondria then fuse with the recipient cell’s endogenous mitochondrial network, ensuring long-term survival and functional integrity.
The team validated the approach using three classic mitochondrial defect cell models: Rho 0 cells (which completely lack mtDNA), and patient-derived cells carrying either mtDNA deletions or point mutations. Results showed that transplanted healthy mitochondria successfully integrated with the endogenous mitochondrial network in all models.
Treatment with the encapsulated mitochondria compensated for the loss, deletion, or mutation of mtDNA, thereby rescuing the associated bioenergetic and biochemical defects in patient-derived cells with mitochondrial disorders.
Furthermore, the researchers evaluated the therapeutic potential of mitochondrial capsule transplantation in vivo using murine and monkey models. In Ndufs4 knockout mice—a model of Leigh syndrome, a severe mitochondrial disorder—mitochondrial capsule transplantation significantly improved motor performance and extended survival. In Dguok knockout mice, which recapitulate mitochondrial DNA depletion syndrome, the treatment restored mtDNA copy number in hepatocytes and alleviated hepatic dysfunction.
In addition, in a pharmacologically induced mouse model of Parkinson’s disease, mitochondrial capsules rescued neuron loss, improved motor skills, and restored mitochondrial function in the affected brain regions.
This study demonstrates the potential of mitochondrial capsules as a treatment for mitochondrial disorders and proposes an “organelle therapy” strategy for regenerative medicine.