Loss of mitochondrial DNA helicase in retinal macroglia drives neovascular retinopathy.

Retinopathy is a common symptom in mitochondrial diseases, and a leading cause of blindness in working-age individuals, often arising as a consequence of diabetes. Here, we demonstrate that postnatal loss of the replicative helicase of mitochondrial DNA in the astrocytes and Müller glia induces neovascular retinopathy. In these retinas, the macroglia show pathological reactivation, leading to hallmark features of neovascularization with blood-retina-barrier leakage, secondary microgliosis, and complement cascade activation. Similar reactivation of astrocytes in the cerebral cortex does not compromise vascular integrity, indicating tissue-specific roles of mitochondrial metabolism in macroglia for vascular homeostasis. Three secreted angiogenic factors-Fgf2, Pgf, and Lcn2-known to contribute to diabetic retinopathy, were induced. Spike recordings of the most sensitive retinal ganglion cells revealed normal rod function and intact retinal coding. These findings highlight the critical role of glial mitochondrial metabolism in neovascular retinopathy, with important implications for therapy development for mitochondrial and common forms of vision loss.