Fig. 4

Loss of NMNAT2 reduces NAD⁺ levels and impairs the NAD redox potential in distal axons. A Levels of NAD⁺ and NADH and calculated NAD⁺/NADH ratios in DIV8 ctrl and KO cortical neurons as measured by the NAD⁺/NADH-Glo assay and normalized to protein amounts. Readings from 28 ctrl and 28 KO culture wells from 4 independent culture experiments; unpaired t-test was used for NADH while Mann–Whitney test was used for both NAD⁺ and NAD⁺/NADH ratios due to their distributions. B Representative images showing signals emitted from the SoNar (NAD⁺/NADH) ratiometric sensor for NAD.⁺ and NADH in the proximal and distal axons of DIV 8 ctrl or KO cortical neurons. Scale bar, 20 um. C NAD + /NADH ratios in soma, proximal and distal axons of DIV7 and 8 ctrl and KO cortical neurons revealed by F488/F440 ratiometric measurements of the SoNar sensor (Soma: 25 ctrl and 24 KO from 2 independent experiments; proximal axon segments: 19 ctrl and 20 KO from 3 independent experiments; distal axon segments: 26 ctrl and 30 KO from 3 independent experiments; two-way ANOVA with Tukey's multiple comparisons test). All above data represents mean ± SEM, ****p < 0.0001