Atherosclerosis is considered an inflammatory disease caused by the accumulation, modification and immune cell recognition of low-density lipoproteins in the arterial wall. Plaque macrophages are held to be the main drivers of disease activity, whereas smooth muscle cells (SMCs) have traditionally been considered protective by forming fibrous tissue that stabilises plaques from undergoing rupture and causing thrombosis. In the present project, we challenge this dichotomous view of cellular villains and heroes in atherosclerosis. Using lineage tracking techniques in mice, we and others have uncovered a large population of SMCs in plaques, which has escaped detection because the cells completely lose conventional SMC phenotype. Strikingly, we have found that the entire plaque SMC population derives from only few founder SMCs that undergo massive clonal expansion and phenotypic modulation during lesion formation. We hypothesise that the balance between the different modulated SMC subtypes and the functions they carry are central to lesion progression. In EXPLOSIA we will address this hypothesis in 3 steps. First, we will conduct a comparative analysis of clonal structure in mice, minipigs, and humans. Second, we will determine links between SMC subtypes, their gene expression programs, and atherosclerotic disease activity by combining single-cell transcriptomics with novel techniques to alter atherosclerotic disease activity in gene-modified mice and minipigs. Third, we will develop techniques for manipulating genes in modulated plaque SMCs and test the causal role of perturbing SMC subtypes and function for lesion progression. The aim of the project is to answer the following key questions for a deeper understanding of atherosclerosis: - What is the clonal architecture of SMCs in human atherosclerosis? - What is the SMC gene expression signature of atherosclerotic disease activity? - Can interventions targeting SMCs prevent dangerous lesion development?

The UNLIMITED project addresses the critical challenges of lipid immunometabolism, a rapidly emerging field with transformative potential for treating immune-mediated diseases such as cancer, autoimmunity and metabolic disorders. Lipid metabolism has been recently recognized as a regulator of immune cell function, yet the intricate interactions between lipid pathways and immune responses within tissue-specific microenvironments remain poorly understood. This knowledge gap hampers the development of precision therapies tailored to the metabolic needs of immune cells in diverse tissue niches. To tackle these challenges, UNLIMITED will train 15 Doctoral Candidates in cutting-edge interdisciplinary research, equipping them with expertise spanning immunology, bioinformatics, metabolism, and drug development. A key feature of UNLIMITED training programme is the integration of leading-edge methodologies, such as multi-omics machine learning, single-cell technologies, CRISPR-Cas9, and spatial metabolomics, alongside groundbreaking techniques pioneered by consortium partners, including SCENITH, Met-Flow, click-chemistry, LIPSTIC, and advanced lipidomics. UNLIMITED’s training program emphasizes a holistic, interdisciplinary approach, providing DCs with technical skills, unparalleled expertise, and transferable competencies to thrive in academic and industrial sectors. The project will unlock unprecedented insights into how lipid metabolic pathways regulate immune cell function and adapt to changes in the tissue microenvironment. This knowledge will enable the identification of novel therapeutic targets and pioneering precision therapies for immune-related diseases. This bold initiative strengthens Europe’s leadership in health innovation, creating a new generation of highly skilled researchers ready to transform global healthcare and advance therapeutic frontiers.