NAD+ loss, a new player in AhR biology: Prevention of thymus atrophy and hepatosteatosis by NAD+ repletion Academic Article uri icon


MeSH Major

  • Air Pollution, Indoor
  • Asbestos
  • Neoplasms
  • Public Health


  • Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin, TCDD) is a carcinogenic and highly toxic industrial byproduct that persists in the environment and produces a pleiotropic toxicity syndrome across vertebrate species that includes wasting, hepatosteatosis, and thymus atrophy. Dioxin toxicities require binding and activation of the aryl hydrocarbon receptor (AhR), a ligand activated transcription factor. However, after nearly 50 years of study, it remains unknown how AhR activation by dioxin produces toxic effects. Here, using the chick embryo close to hatching, a well-accepted model for dioxin toxicity, we identify NAD(+) loss through PARP activation as a novel unifying mechanism for diverse effects of dioxin in vivo. We show that NAD(+) loss is attributable to increased PARP activity in thymus and liver, as cotreatment with dioxin and the PARP inhibitor PJ34 increased NAD(+) levels and prevented both thymus atrophy and hepatosteatosis. Our findings additionally support a role for decreased NAD(+) dependent Sirt6 activity in mediating dioxin toxicity following PARP activation. Strikingly, treatment in vivo with the NAD(+) repleting agent nicotinamide, a form of vitamin B3, prevented thymus atrophy and hepatosteatosis by dioxin and increased sirtuin activity, providing a therapeutic approach for preventing dioxin toxicities in vivo.

publication date

  • December 2017



  • Academic Article



  • eng

PubMed Central ID

  • PMC5442136

Digital Object Identifier (DOI)

  • 10.1038/s41598-017-02332-9

PubMed ID

  • 28536482

Additional Document Info

start page

  • 2268


  • 7


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