Science Bite (3 minute oral presentation with PPT in live session with pre-recorded e-poster) Lorne Infection and Immunity 2021

Characterisation of a novel type I interferon pathway and its implications in inflammatory disease (#113)

Stephanie Huang 1 , Bing Li 2 , Nicole De Weerd 1 , Eveline de Geus 1 , Jennifer Volaric 1 , Niamh Mangan 1 , Edward Giles 3 , Clare Bryant 4 , David Klenerman 2 , Paul Hertzog 1
  1. Hudson Institute of Medical Research, Clayton, VICTORIA, Australia
  2. Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
  3. Department of Paediatrics, Monash Children's Hospital, Melbourne, Victoria, Australia
  4. Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom

Type I interferon (IFN) signalling is integral to eliminating infections and cancer. Conventional signalling requires the binding of IFN to both transmembrane receptor subunits, IFNAR1 and IFNAR2, to activate the classical JAK-STAT pathway [1, 2]. Our lab recently demonstrated that IFNβ can bind to the IFNAR1 subunit in the absence of IFNAR2 and activate STAT-independent signalling and unique interferon-regulated genes [3]. Activation of this pathway using Ifnar2-/- mice has been shown to result in lethality following lipopolysaccharide (LPS) induced septic shock and exacerbate neuronal cell death in ischaemic stroke models [3, 4]. This project aims to characterise this novel, non-canonical IFN pathway at the cellular, tissue, and molecular levels to better understand its activation and involvement in pathogenesis, as well as its potential for therapeutic intervention.

Cellular: To investigate this novel pathway in vivo, Ifnar2-/- mice are administered intraperitoneal IFNβ, the IFN selectively produced in LPS sepsis, and peritoneal exudate cells are extracted for FACS analysis. A reduction in peritoneal B cell numbers is observed, with the induction of TREM1 (a non-canonical marker) expression detected on macrophages. Furthermore, Ifnar2-/- B cells and macrophages were found to down-regulate IFNAR1 following IFNβ stimulation in vitro, indicating their potential role as the populations participating in the pathogenesis of the septic shock model. Tissue: To establish the potential of non-canonical signalling in mucosal tissues, we used immunohistochemistry to reveal strong IFNAR1 expression throughout the cytoplasm of the stromal cells from gastrointestinal tract (GIT) tissues with the absence of IFNAR2, indicating a potential for independent receptor activation (non-canonical signalling). Conversely, expression of the subunits is reversed in the female reproductive tract (FRT), suggesting non-canonical signalling may be tissue specific. Molecular: Using single-molecule microscopy to characterise the receptor dynamics of non-canonical signalling, we showed that the presence of IFNAR2 slows down the mobility of IFNAR1 upon the addition of IFNβ, whereas no change in surface dynamics was observed for IFNAR1 expressed alone, revealing a different kinetic profile for the novel IFNβ:IFNAR1 axis.

  1. Hwang, S.Y., et al., A null mutation in the gene encoding a type I interferon receptor component eliminates antiproliferative and antiviral responses to interferons alpha and beta and alters macrophage responses. Proc Natl Acad Sci U S A, 1995. 92(24): p. 11284-8
  2. de Weerd, N.A. and T. Nguyen, The interferons and their receptors--distribution and regulation. Immunol Cell Biol, 2012. 90(5): p. 483-91
  3. de Weerd, N.A., et al., Structural basis of a unique interferon-b signaling axis mediated via the receptor IFNAR1. Nature Immunology, 2013. 14: p. 901-907
  4. Zhang, M., et al., Type-I interferon signalling through IFNAR1 plays a deleterious role in the outcome after stroke. Neurochemistry International, 2017. 108: p. 472-480