Transgenic NADH dehydrogenase restores oxygen regulation of breathing in mitochondrial complex I-deficient mice.

Jiménez-Gómez, Blanca; Ortega-Sáenz, Patricia; Gao, Lin; González-Rodríguez, Patricia; García-Flores, Paula; Chandel, Navdeep; López-Barneo, José · Nat Commun · 2023

basic_science · Level V

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Abstract

The hypoxic ventilatory response (HVR) is a life-saving reflex, triggered by the activation of chemoreceptor glomus cells in the carotid body (CB) connected with the brainstem respiratory center. The molecular mechanisms underlying glomus cell acute oxygen (O<sub>2</sub>) sensing are unclear. Genetic disruption of mitochondrial complex I (MCI) selectively abolishes the HVR and glomus cell responsiveness to hypoxia. However, it is unknown what functions of MCI (metabolic, proton transport, or signaling) are essential for O<sub>2</sub> sensing. Here we show that transgenic mitochondrial expression of NDI1, a single-molecule yeast NADH/quinone oxidoreductase that does not directly contribute to proton pumping, fully recovers the HVR and glomus cell sensitivity to hypoxia in MCI-deficient mice. Therefore, maintenance of mitochondrial NADH dehydrogenase activity and the electron transport chain are absolutely necessary for O<sub>2</sub>-dependent regulation of breathing. NDI1 expression also rescues other systemic defects caused by MCI deficiency. These data explain the role of MCI in acute O<sub>2</sub> sensing by arterial chemoreceptors and demonstrate the optimal recovery of complex organismal functions by gene therapy.

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