Activation of the NLRP1 inflammasome in human keratinocytes by the dsDNA mimetic poly(dA:dT)

Proc Natl Acad Sci U S A. 2023 Jan 31;120(5):e2213777120. doi: 10.1073/pnas.2213777120. Epub 2023 Jan 24.


The accrual of cytosolic DNA leads to transcription of type I IFNs, proteolytic maturation of the IL-1 family of cytokines, and pyroptotic cell death. Caspase-1 cleaves pro-IL1β to generate mature bioactive cytokine and gasdermin D which facilitates IL-1 release and pyroptotic cell death. Absent in melanoma-2 (AIM2) is a sensor of dsDNA leading to caspase-1 activation, although in human monocytes, cGAS-STING acting upstream of NLRP3 mediates the dsDNA-activated inflammasome response. In healthy human keratinocytes, AIM2 is not expressed yet caspase-1 is activated by the synthetic dsDNA mimetic poly(dA:dT). Here, we show that this response is not mediated by either AIM2 or the cGAS-STING-NLRP3 pathway and is instead dependent on NLRP1. Poly(dA:dT) is unique in its ability to activate NLRP1, as conventional linear dsDNAs fail to elicit NLRP1 activation. DsRNA was recently shown to activate NLRP1 and prior work has shown that poly(dA:dT) is transcribed into an RNA intermediate that stimulates the RNA sensor RIG-I. However, poly(dA:dT)-dependent RNA intermediates are insufficient to activate NLRP1. Instead, poly(dA:dT) results in oxidative nucleic acid damage and cellular stress, events which activate MAP3 kinases including ZAKα that converge on p38 to activate NLRP1. Collectively, this work defines a new activator of NLRP1, broadening our understanding of sensors that recognize poly(dA:dT) and advances the understanding of the immunostimulatory potential of this potent adjuvant.

Keywords: AIM2; NLRP1; inflammasome; keratinocyte; poly(dA:dT).

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Caspase 1 / metabolism
  • Cytokines / metabolism
  • DNA / metabolism
  • Humans
  • Inflammasomes* / metabolism
  • Interleukin-1 / metabolism
  • Keratinocytes / metabolism
  • NLR Family, Pyrin Domain-Containing 3 Protein* / metabolism
  • NLR Proteins / metabolism
  • RNA / metabolism


  • Inflammasomes
  • NLR Family, Pyrin Domain-Containing 3 Protein
  • Cytokines
  • DNA
  • Caspase 1
  • RNA
  • Interleukin-1
  • NLRP1 protein, human
  • NLR Proteins