Notably, the expression analysis of the main muscle genes involved in NAD+ biosynthesis pathways (salvage and Preiss–Handler pathways) revealed a strongly diminished muscle isoform of nicotinamide riboside kinase (Nrk), Nrk2, in PBS-treated TB-mice, and sACVR/c completely rescued it (P < 0.05; Figure 4D). Here, NRK is linked to tuberculosis.