Abstract
The notion of clonal cell populations in human atherosclerosis has been suggested but not demonstrated. Somatic mutations are used to define cellular clones in tumors. Here, we characterized the mutational landscape of human carotid plaques through whole-exome sequencing to explore the presence of clonal cell populations. Somatic mutations were identified in 12 of 13 investigated plaques, while no mutations were detected in 11 non-atherosclerotic arteries. Mutated clones often constituted over 10% of the sample cell population, with genes related to the contractile apparatus enriched for mutations. In carriers of clonal hematopoiesis of indeterminate potential (CHIP), hematopoietic clones had infiltrated the plaque tissue and constituted substantial fractions of the plaque cell population alongside locally expanded clones. Our findings establish somatic mutations as a common feature of human atherosclerosis and demonstrate the existence of mutated clones expanding locally, as well as CHIP clones invading from the circulation. While our data do not support plaque monoclonality, we observed a pattern suggesting the coexistence of multiple mutated clones of considerable size spanning different regions of plaques. Mutated clones are likely to be relevant to disease development, and somatic mutations will serve as a convenient tool to uncover novel pathological processes of atherosclerosis in future studies.
Authors
Lasse Bach Steffensen, Stephanie Kavan, Pia Søndergaard Jensen, Matilde Kvist Pedersen, Steffen Møller Bøttger, Martin Jakob Larsen, Maja Dembic, Otto Bergman, Ljubica Matic, Ulf Hedin, Lars van Brakel Andersen, Jes Sanddal Lindholt, Kim Christian Houlind, Lars Peter Riber, Mads Thomassen, Lars Melholt Rasmussen
Figure 4
Contribution of clonal hematopoiesis of indeterminate potential (CHIP) clones to the carotid plaque cell population.
