Recombinant Mitochondrial Transcription Factor A with N-terminal Mitochondrial Transduction Domain Increases Respiration and Mitochondrial Gene Expression in G11778A Leber's Hereditary Optic Neuropathy Cybrid Cells

Abstract Diseases involving mitochondrial defects usually manifest themselves in high-energy, post-mitotic tissues such as brain, retina, skeletal and cardiac muscle and frequently cause deficiencies in mitochondrial bioenergetics. We have developed a scalable procedure to produce recombinant human mitochondrial transcription factor A (TFAM) modified with an N-terminal protein transduction domain (PTD) and mitochondrial localization signal (MLS) that allow it to cross membranes and enter mitochondria through its "mitochondrial transduction domain" (MTD,=PTD+MLS). in vitro studies in a classic mitochondrial disease cell model demonstrated that Alexa488-labeled MTD-TFAM rapidly entered the mitochondrial compartment. MTD-TFAM treatment of these cell lines reversibly increased oxygen consumption (respiration) rates 3-fold, levels of respiratory proteins and mitochondrial gene expression. in vivo results demonstrated that respiration increased to lesser degrees in mitochondria from tissues of mice injected with MTD-TFAM. MTD-TFAM can alter mitochondrial bioenergetics and holds promise for treatment of mitochondrial diseases involving deficiencies of energy production.