promote the accumulation of deleterious mutations in their own mitochondria and long-term survival. Transfer of intact mitochondria can contribute to tissue repair in vivo. Bone marrow-derived stem cells (BMSCs) injected into mice with acute lung injury transfer their mitochondria to lung alveoli cells and protect them against injury. Overexpression of Miro1, a protein connecting mitochondria to cytoskeletal motor proteins, leads to enhanced transfer of mitochondria from MSCs into stressed epithelial cells via TNTs in mice. In vivo horizontal transfer of mitochondria can occur in cancer cells which upon mitochondrial damage acquire mtDNA from surrounding donor healthy cells. This process restores transcription and translation of mtDNA-encoded genes as well as respiration. References Mitochondria Cell anatomy