Parkinson's disease (PD) is the eponym attached to the most prevalent neurodegenerative
movement disorder of adults, derived from observations of an early nineteenth century physician and paleontologist, James Parkinson, and is now recognized to encompass much more than a
movement disorder clinically or dopamine neuron death pathologically. Most PD ( approximately 90%) is sporadic (sPD), is associated with mitochondrial deficiencies and has been studied in cell and animal models arising from the use of mitochondrial toxins that unfortunately have not predicted clinical efficacy to slow
disease progression in humans. We have extensively studied the cytoplasmic hybrid ("cybrid") model of sPD in which donor mtDNAs are introduced into and expressed in neural
tumor cells with identical nuclear genetic and environmental backgrounds. sPD cybrids demonstrate many abnormalities in which increased oxidative stress drives downstream
antioxidant response and cell death activating signaling pathways. sPD cybrids regulate mitochondrial ETC genes and gene ontology families like sPD brain. sPD cybrids spontaneously form Lewy bodies and Lewy neurites, linking
mtDNA expression to neuropathology, and demonstrate impaired organelle transport in processes and reduced mitochondrial respiration. Our recent studies show that near-infrared
laser light therapy normalizes mitochondrial movement and can stimulate respiration in sPD cybrid neurons, and mitochondrial gene
therapy can restore respiration and stimulate mitochondrial ETC gene and
protein expression. sPD cybrids have provided multiple lines of circumstantial evidence linking
mtDNA to sPD pathogenesis and can serve as platforms for
therapy development. sPD cybrid models can be improved by the use of non-
tumor human stem cell-derived neural precursor cells and by an introduction of postmortem brain
mtDNA to test its causality directly.