Fig. 4: Mitochondrial NADH and hypoxia signaling in complex I-deficient and NDI1-expressing glomus cells.

a Scheme representing the electron transport chain (ETC) in glomus cells and its dynamic changes in response to hypoxia (Hx, red lines and symbols). IMM, inner mitochondrial membrane. b Scheme representing the ETC of glomus cells in which MCI is replaced with NDI1. Dynamic changes in hypoxia are represented by red lines and symbols. c–e, Representative recordings of changes in NADH autofluorescence recorded in response to hypoxia (Hx, PO₂ ~15 mmHg) in dispersed glomus cells from WT (c), KO (d) and KO/NDI1 (e) mice. Calibration bars as indicated in (c). f–h Microfluorimetric recordings illustrating changes in NADH induced by hypoxia (Hx), rotenone (1 μM) and the application of hypoxia in the presence of rotenone in dispersed glomus cells from WT (f) KO (g) and KO/NDI1 (h) mice. Calibration bars as indicated in (c). i Average basal levels of NADH (in arbitrary units, a.u) recorded in glomus cells from WT mice (254 ± 28, n = 17/6 cells/mice), KO mice (372 ± 36, n = 31/6 cells/mice) and KO/NDI1 mice (234 ± 13, n = 32/6 cells/mice). Data are expressed as mean ± SEM. P values calculated by one-way ANOVA followed by Tukey’s multiple comparisons post hoc test. j–l Boxplots representing increase in NADH autofluorescence in response to hypoxia (j, n = panel i), rotenone (k, WT, n = 14/6; KO, n = 25/6, KO/NDI1, n = 28/6 cells/mice) and rotenone plus hypoxia (l, WT, n = 10/6; KO, n = 18/6, KO/NDI1, n = 28/6 cells/mice) recorded in dispersed glomus cells from WT (blue dots), KO (yellow dots) and KO/NDI1 (brown dots) mice. The boxplots in (j, k, l) indicate median (middle line), 25th, 75th percentile (box), and largest and smallest values range (whiskers). Indicated P values were calculated with Kruskal-Wallis test followed by Dunn’s multiple comparisons post hoc test. Source data are provided as a Source Data file.