To confirm that mitochondrial biogenesis and function were impaired by Npm1 heterozygous deletion and that such impairment contributed to colitis severity, we used bezafibrate, an agonist of the transcription factors peroxisome proliferator-activated receptor (PPAR) γ coactivator 1α (PGC1α) that stimulates mitochondrial OXPHOS and biogenesis41,42. Here, NPM1 is linked to colitis.