E-Poster with pre-recorded video presentation Lorne Infection and Immunity 2021

Activation of stimulator of interferon genes in dendritic cells induces interferon-lambda and subset- and species-specific dendritic cell death (#262)

Ee Shan Pang 1 , Ghazal Daraj 2 , Christophe Macri 3 , Hubertus Hochrein 4 , Kelly Anne Masterman 2 , Yifan Zhan 5 , Dominic Denardo 1 , Katherine Balka 1 , Benjamin Kile 1 , Kate Lawlor 6 , Kristen Radford 2 , Mark Wright 7 , Meredith O'Keeffe 1
  1. Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
  2. Mater Research-University of Queensland, Translational Research Institute, Woolloongabba, QLD, Australia
  3. Department of Biochemistry & Molecular Biology, Bio21 Institute, University of Melbourne, Parkville, VIC, Australia
  4. Department of Research, Bavarian Nordic, Fraunhoferstrasse 13, D-82152 Martinsried, Germany
  5. The Walter and Eliza Hall Institute, University of Melbourne, Parkville, VIC, Australia
  6. Hudson Institute of Medical Research, Clayton, VIC, Australia
  7. Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia

Stimulator of Interferon (IFN) Genes (STING) is a cytosolic DNA sensor that recognises cyclic dinucleotides (CDNs), such as the bacterial product cyclic-guanosine monophosphate-adenosine monophosphate (cGAMP). Other forms of cytosolic DNA from viruses or host cells can be converted into CDNs by an enzyme cGAMP synthase (cGAS). Activation of STING results in the production of Type I IFN through the phosphorylation of TANK-binding kinase 1 (TBK1) and IFN regulatory factor 3 (IRF3). As dendritic cells (DCs) are key antigen presenting cells that link the innate and adaptive immune systems, it is important to understand the role and effects STING activation have in DCs and how this subsequently mediates immunity against foreign or aberrant DNA insults. However, DCs interrogated in many studies investigating STING activation use in vitro-generated DCs instead of putative ex vivo DCs. We have previously shown that there is differential expression of STING among various DC subsets. However, the direct effects of STING activation on these DC subsets are incompletely understood. Here, we report that mouse and humanised mouse splenic DC subsets as well as human blood DCs are activated by CDN stimulation and all produce Type III IFN but only conventional DC2 (cDC2) and plasmacytoid DCs (pDCs) produce Type I IFN in response to CDN stimulation. However, only mouse pDCs aberrantly express extremely high levels of activation markers CD86 and CD80 and are ablated rapidly after STING activation. Some DC death was also observed in mouse and human cDC2s, but not in human pDCs. This ablation is STING-dependent and occurs via a cell-intrinsic mechanism involving intrinsic apoptosis. These observations demonstrate the differential effects STING activation has on DC subsets as well as highlight a discordance amongst mouse and human DCs during activation, which serve as an important consideration in future translational research and therapeutic design.