Negative Regulation of Inflammatory Responses Revealed with Camelid Nanobodies

Objectif

The innate immune system evokes inflammation to control pathogens or damage. Sophisticated mechanisms interpret molecular triggers to activate inflammasomes or transcription of pro-inflammatory genes. While numerous autoinflammatory conditions underline the need to control inflammation, we still rely on simplistic models to understand its negative regulation. I hypothesize that an intricate signaling network interprets information to prevent or downregulate inflammation. Understanding these so far elusive processes demands radically new cell biology tools, which I will develop and apply in ‘DEFLAMMATION’.

I propose to define signaling hubs that integrate cellular input and coordinate effectors to actively downregulate inflammation where beneficial to the organism. To yield unprecedented molecular insights, we will apply nanobodies to inhibit protein function, manipulate post-translation modifications, and visualize endogenous proteins and their binary interactions. I hypothesize that two poorly understood members of the NLR family, NLRC3 and NLRX1, act as signaling hubs that coordinate negative regulation of pro-inflammatory gene expression. No such coordinator is known for inflammasomes. In objective 1, we will pinpoint how NLRC3 controls inflammation and T cell activity. I hypothesize that NLRC3 forms anti-inflammatory signalosomes to control the ubiquitination status of pro-inflammatory signaling components. In objective 2, we will reveal how NLRX1 counteracts interferon responses, inflammation, and proliferation. We will explore whether NLRX1 activation coordinates organelle-specific autophagy to remove pro-inflammatory signaling complexes. In objective 3, we will identify novel regulatory circuits that control inflammasome activation using CRISPR/Cas9 and cDNA screens, taking advantage of a novel reporter we have developed.

The anticipated results will reveal entirely new layers of regulation of inflammation with implications for therapeutic interventio