Cell-permeable protein therapy for complex I dysfunction.

Complex I deficiency is difficult to treat because of the size and complexity of the multi-subunit enzyme complex. Mutations or deletions in the mitochondrial genome are not amenable to gene therapy. However, animal studies have shown that yeast-derived internal NADH quinone oxidoreductase (Ndi1) can be delivered as a cell-permeable recombinant protein (Tat-Ndi1) that can functionally replace complex I damaged by ischemia/reperfusion. Current and future treatment of disorders affecting complex I are discussed, including the use of Tat-Ndi1.