Project ID CM-HD2023_50

ThemeCM-HD

Co Supervisor 1A Department of Infectious Diseases/ School of Immunology & Microbial Sciences / Faculty of Life Sciences & MedicineWebsite

Co Supervisor 1B Department of Infectious Diseases/ School of Immunology & Microbial Sciences / Faculty of Life Sciences & MedicineWebsite

Regulation of the innate immune response by N4BP1

The innate immune system is the first line of defence against pathogens. When a bacteria or virus is sensed by our cells, there is potent upregulation of pro-inflammatory cytokines and other genes, which are critical to stop the infection. However, if inflammation is dysregulated, severe diseases such as COVID-19 or autoimmune syndromes can develop. To prevent this, our immune system has evolved control mechanisms that supress inflammatory gene expression. One of these is N4BP1, which is in a family of proteins containing an endoribonuclease domain that includes KHNYN and Regnase 1-4. These proteins negatively regulate inflammatory gene expression and also inhibit pathogen replication, often by degrading RNA. Highlighting its importance, N4BP1 knockout mice suffer from immune dysregulation and inflammation and have altered resistance to bacterial infection. N4BP1 has also been shown to restrict viral replication. However, how it inhibits inflammatory gene expression and pathogen replication is not clear. We hypothesise that N4BP1 is a critical component of the innate immune response to bacterial and viral pathogens.

Aim 1: Characterise the pathogen recognition signalling pathways and genes that are controlled by N4BP1.
Aim 2: Identify cellular proteins that N4BP1 interacts with to regulate the innate immune response.
Aim 3: Determine if N4BP1 directly targets viral or bacterial replication and whether viral or bacterial virulence factors inhibit its activity.

Techniques: RNA-seq, qRT-PCR, ELISA, western blotting, protein-protein interaction assays, recombinant DNA cloning, CRISPR-Cas gene editing, flow cytometry, microscopy, in vitro and in vivo viral and bacterial infection models.

One representative publication from each co-supervisor:

• A family of conserved bacterial virulence factors dampens interferon responses by blocking calcium signaling. Alphonse N, Wanford JJ, Voak AA, Gay J, Venkhaya S, Burroughs O, Mathew S, Lee T, Evans SL, Zhao W, Frowde K, Alrehaili A, Dickenson RE, Munk M, Panina S, Mahmood IF, Llorian M, Stanifer ML, Boulant S, Berchtold MW, Bergeron JRC, Wack A, Lesser CF, Odendall C. Cell. 2022 May 11:S0092-8674(22)00526-8.

• KHNYN is essential for the zinc finger antiviral protein (ZAP) to restrict HIV-1 containing clustered CpG dinucleotides. Ficarelli M, Wilson H, Pedro Galão R, Mazzon M, Antzin-Anduetza I, Marsh M, Neil SJ, Swanson CM. Elife. 2019 Jul 9;8:e46767.