James Vince-Projects

James Vince-Projects

Researcher: 

Projects

Mechanisms of RIP1 and RIP3 kinase mediated IL-1β activation

RIP1 and RIP3 kinases form part of a complex termed the 'ripoptosome', which can induce necroptotic cell death. RIP3 kinase-dependent necroptotic signaling has been implicated in resistance to viral infection, but appears to be pathologic in models of tissue damage.
We have revealed a novel function of the “ripoptosome” complex in innate immune cells. We are now examining:

  • How the ripoptosome complex is repressed by IAP proteins
  • How the ripoptosome signals to activate the NLRP3 inflammasome
  • Physiological mechanisms and disease models that result from ripoptosome driven IL-1β inflammation

Reference: Vince JE, Wong WW, Gentle I, Lawlor KE, Allam R, O'Reilly L, Mason K, Gross O, Ma S, Guarda G, Anderton H, Castillo R, Hacker G, Silke J, Tschopp J. Inhibitor of apoptosis proteins limit RIP3 kinase-dependent interleukin-1 activation. Immunity. 2012 Feb 24;36(2):215-27. PMID: 22365665.

 

New roles for caspase-8 in inflammation

Caspase-1 cleavage of IL-1β is regarded as the dominant mechanism by which IL-1β is activated. However, surprisingly, we have found that caspase-8 can also cleave, and thereby activate, IL-1β. Our studies also suggest that RIP3 kinase signalling facilitates caspase-8 ubiquitylation and activation, and that caspase-8 can signal cytokine induction. We now aim to i) determine the mechanism by which RIP3 signals caspase-8 ubiquitylation and activation, ii) probe the role of caspase-8 in modulating cytokine production, and iii) understand the relevance and (disease) circumstances of caspase-8 mediated IL-1β activation and cytokine production in vivo. 

Reference: Allam R, Lawlor KE, Yu EC, Mildenhall AL, Moujalled DM, Lewis RS, Ke F, Mason KD, White MJ, Stacey KJ, Strasser A, O'Reilly LA, Alexander W, Kile BT, Vaux DL, Vince JE.Mitochondrial apoptosis is dispensable for NLRP3 inflammasome activation but non-apoptotic caspase-8 is required for inflammasome priming. EMBO Rep. 2014 Sep;15(9):982-90. doi: 10.15252/embr.201438463. 

Regulation of inflammasome function

Tumour necrosis factor (TNF) and IL-1 are both pivotal pro-inflammatory cytokines that when dysregulated contribute to a diverse range of diseases. As might be expected from their potential to adversely impact human health, a large body of work has demonstrated how many components required for TNF signalling are exquisitely controlled at multiple levels, including both transcriptional and post-translational regulatory mechanisms. In contrast, since the discovery of the inflammasome complex in 2002, the mechanisms that control inflammasome signalling to allow appropriate inflammatory responses, remains rudimentary. This project seeks to identify transcriptional and post-translational regulators of inflammasome signalling using targeted biochemical approaches as well as genetic and proteomic screening.