De novo NAD(+) synthesis enhances mitochondrial function and improves health

Nicotinamide adenine dinucleotide (NAD(+)) is a cosubstrate for several enzymes, including the sirtuin family of NAD(+)-dependent protein deacylases. Beneficial effects of increased NAD(+) levels and sirtuin activation on mitochondrial homeostasis, organismal metabolism and lifespan have been established across species. Here we show that α-amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD), the enzyme that limits the proportion of ACMS able to undergo spontaneous cyclisation in the de novo NAD(+) synthesis pathway, controls cellular NAD(+) levels via an evolutionary conserved mechanism from C. elegans to the mouse. Genetic and pharmacological inhibition of ACMSD boosts de novo NAD(+) synthesis and SIRT1 activity, ultimately enhancing mitochondrial function. We furthermore characterized a series of potent and selective ACMSD inhibitors, which, given the restricted ACMSD expression in kidney and liver, are of high therapeutic interest to protect these tissues from injury. ACMSD hence is a key modulator of cellular NAD(+) levels, sirtuin activity, and mitochondrial homeostasis in kidney and liver.