Poster Presentation Lorne Infection and Immunity 2022

Characterisation of a novel non-canonical interferon pathway in macrophages (#166)

Stephanie Huang 1 , Nicole De Weerd 1 , Jamie Gearing 1 , Hani Hosseini Far 1 , Jodee Gould 1 , Niamh Mangan 1 , Paul Hertzog 1
  1. Hudson Institute of Medical Research, Clayton, VICTORIA, Australia

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, including TREM1 [3]. Activation of this pathway using Ifnar2-/- mice has been shown to result in lethality following lipopolysaccharide (LPS) induced septic shock and reduce neuronal cell death in ischaemic stroke models [3, 4]. This project aims to characterise this novel, non-canonical IFN pathway using in vivo and in vitro methods to better understand its activation and involvement in pathogenesis, as well as its potential for therapeutic intervention.

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. As the murine in vivo and in vitro work identified macrophages to be a candidate for non-canonical signalling, RNAseq was performed on iPSC macrophages to translate these findings into a human model. IFNAR2-/- iPSC macrophages were stimulated with IFNβ and LPS in vitro, with transcriptomic analysis revealing the induction of non-canonical genes identified in the mouse model. This finding suggests the physiological relevance of this novel pathway in sepsis pathogenesis, and the identification of macrophages as the population responsible may enable their therapeutic depletion in the clinic.

  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.