Spatio-temporal integration of skin inflammation

Project Information

4D-SkINFLAM

Grant agreement ID: 101098003

DOI

10.3030/101098003

EC signature date 12 September 2023

Start date 1 October 2023

End date 30 September 2028

Funded under

• European Research Council (ERC)

Total cost

€ 2 499 188,00

EU contribution

€ 2 499 188,00

Coordinated by

DEUTSCHES RHEUMA FORSCHUNGSZENTRUMBERLIN
Germany

Periodic Reporting for period 1 - 4D-SkINFLAM (Spatio-temporal integration of skin inflammation)

Reporting period: 2023-10-01 to 2026-03-31

Summary of the context and overall objectives of the project

Chronic inflammatory skin diseases such as psoriasis and atopic dermatitis are among the most common immune-mediated disorders worldwide. They cause major morbidity and are linked to systemic comorbidities, yet current therapies mostly target downstream cytokines and do not address the upstream events that initiate and spatially organise inflammation in the epidermis. Human genetics and functional data point to the inflammasome sensors NLRP1 and NLRP10 as key, layer-specific regulators of skin immune homeostasis, but their spatio-temporal activation and consequences in human skin remain poorly understood.
Our project aims to define how NLRP1 (and, in comparison, NLRP10) activation in keratinocytes drives skin inflammation. Specifically, we will: (i) map the spatio-temporal effects of inflammasome signalling in human 3D skin equivalents using optogenetic tools and digital spatial profiling; (ii) dissect how environmental and microbial stressors such as UV, irritants and pathogens activate NLRP1/NLRP10 in distinct epidermal layers; (iii) test how spatially confined inflammasome activity in vivo shapes local and systemic immune responses; and (iv) determine inflammasome pathway activity and associated tissue responses in skin biopsies from patients with psoriasis and atopic dermatitis.
We expect to provide a mechanistic framework for how upstream inflammasome sensors organise inflammatory and anti-inflammatory IL-1 family cytokine responses in space and time, how this affects barrier function, and how dysregulated signalling contributes to human skin disease. Beyond conceptual advances, the project will establish powerful methodological platforms (optogenetic inflammasome control, spatial transcriptomics/proteomics in skin) and identify candidate drug targets at the level of the most proximal drivers of skin inflammation, thus informing future strategies for precision diagnostics and more causally acting therapies.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

We show that pharmacological NLRP1 agonists, UVB and skin-tropic viruses all induce nuclear inflammasomes in human keratinocytes and multiple other human cell types, but not in mouse Nlrp1b-expressing cells, underscoring the need for human tissue and organoid models. Mechanistically, endogenous NLRP1 is enriched in nuclear fractions; intact NACHT/LRR domains, ATPase activity and the long DPP9 isoform are required for efficient nuclear recruitment, defining druggable regulatory nodes. Technologically, we have established Microscoop-based spatial optoproteomics to photo-label proteins at nuclear ASC specks in situ, followed by mass spectrometry. These studies reveal selective co-localisation with PML nuclear bodies and accumulation of SUMO-modified proteins, and pharmacological SUMO pathway inhibition modulates NLRP1 activation. Finally, NLRP1 activation in human monocytes drives extracellular trap formation with DNA and nuclear lamins, providing a plausible link between nuclear damage, autoantigen exposure and systemic autoimmunity. Together, these findings define a new nuclear inflammasome paradigm, establish powerful imaging and spatial proteomics pipelines, and create a strong platform for the ERC project to dissect how chronic NLRP1 activation shapes skin inflammation and to identify precision therapeutic strategies.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Scientifically, the project provides a mechanistic framework for how upstream inflammasomes organise pro- and anti-inflammatory IL-1 family responses in space and time, and how this contributes to skin immune homeostasis versus chronic inflammation. Methodologically, it delivers validated 3D human skin models, optogenetic inflammasome control, and spatial multi-omics workflows that are broadly applicable and reduce reliance on animal testing, in line with EU regulations.
Translationally, the work is expected to generate candidate biomarkers (spatial signatures of inflammasome activity) and upstream drug targets (e.g. NLRP1/NLRP10 and their regulators) that could support more causal and personalised therapies for inflammatory skin disease.
To move from mechanistic insight to patient benefit, the main needs are: Further research and demonstration: validation of inflammasome signatures and targets in larger, longitudinal patient cohorts and functional testing in preclinical models.
By the end of the project, we expect to have: (i) a multi-layered atlas of how NLRP1/NLRP10 inflammasome activity is organised in human epidermis; (ii) validated 3D skin models and spatial omics pipelines to interrogate these pathways; (iii) defined inflammasome-centric molecular signatures in patient skin; and (iv) a shortlist of upstream, mechanistically grounded targets and biomarkers ready for translational development in inflammatory skin disease.