Since circulating lipoproteins routinely contain lipids that are structurally similar to lipid antigens, I hypothesized that circulating lipoproteins would also contain lipid antigens for iNKT cells. I developed CD1d-sortagging as a novel and innovative approach for lipid antigen identification. CD1d-sortagging employs bacterial sortase enzymes for site-specific cleavage and biotin labeling of CD1d-lipid antigen complexes, followed by isolation and potentially identification of the lipid antigens. Using CD1d-sortagging and state-of-the-art microscopy techniques, I have been able to show that circulating lipoproteins can indeed contain lipid antigens for iNKT cell function. Furthermore, I discovered that the containment of lipid antigens in lipoproteins affects iNKT cell function. Finally, I showed that manipulation of lipoprotein metabolism impacts the delivery of lipid antigens to antigen presenting cells, and thereby the function of iNKT cells. In conclusion, the MSCA Fellowship project showed that lipoproteins are not only involved in plaque development as lipid deposits, but also play a role in the activation of iNKT cells.
Exploitation of the results:
The MSCA Fellowship enabled the development of CD1d-sortagging in vitro, as a novel and promising tool to identify CD1d-associated lipid antigens. Though the use of CD1d-sortagging in vivo has yet to be shown, CD1d-sortagging may provide novel opportunities for lipid antigen identification in many other settings. We are in close communication with the Knowledge Transfer office at the University to exploit successful use in vivo, hopefully in the near future.
Dissemination of the results:
The study results have been disseminated in several ways:
- Scientific presentations: 2018 EULAR congress, 2019 ESC congress, 2020 internal seminar Kennedy Institute University of Oxford, 2020 Seminar at the Weatherall Institute of Molecular Medicine, University of Oxford, 2020 Oxford Metabolic Health Symposium.
- Scientific publications: 2 scientific publications have been submitted, 1 is currently under revision.
- Patient involvement: study plans and results were presented at the yearly Pulse meeting of the Dutch Heart foundation, which provides a platform for interaction with patients, industry, and policy makers.
- Public engagement: I have participated in the European Researcher’s night, and visited a primary school to present my research and inspire a passion for science.
Impact of COVID-19 on work performed:
- The generation of a CD1d-sortagging mouse model was delayed. Therefore, identification of lipoprotein-associated iNKT cell antigens in vivo could not yet be performed.
- There were no human plaques available during the COVID-19 epidemic. Therefore, human atheroma cell cultures could not be employed to study the impact of plaque-associated lipid antigens on the intra-lesional cytokine environment.
