Abstract 17202: Cross-Species Evaluation of Cellular TNF Receptor-Associated Factor (TRAF) Expression, Regulation and Function in Murine and Human Atherosclerosis
Mark Colin Gissler, Hauke Horstmann, Dirk Westermann, Dennis Wolf- Physiology (medical)
- Cardiology and Cardiovascular Medicine
Background: TNF receptor-associated factors (TRAFs) potently modulate immune cell function and activity in a variety of inflammatory diseases. However, due to the limited availability of viable animal models, the roles of TRAF3, TRAF4 and TRAF7 in atherosclerosis remain unknown to date. Here, we present a stepwise multiparametric approach to delineate cellular expression, regulation and implications on cardiovascular outcomes of TRAFs in murine and human atherosclerosis.
Methods: To induce atherosclerotic lesion formation, LDLR-/- mice were fed a high cholesterol diet for 20 weeks and expression of TRAF1-7 was determined in whole tissue lysates of the murine aorta as well as on sorted leukocytes. We then performed scRNAseq and bioinformatical integration of leukocytes from human and mouse atherosclerotic plaques to analyze and compare single cell TRAF expression in both species. Finally, potential significance of cellular TRAF3, 4 and 7 expression in human atherosclerosis was assessed in three independent clinical study cohorts.
Results: Aortic TRAF3 and TRAF4 expression was 2-fold higher in atherosclerotic mice compared to controls, whereas TRAF7 expression was significantly lower. Between species, humans exhibited higher cellular TRAF3 expression than mice. Further, TRAF7 blood expression was lower in patients with an unstable CAD angiogram than in patients with stable CAD while expression of TRAF3 in human atherosclerotic plaques was significantly higher in unstable compared to stable lesions. Finally, TRAF3 expression on circulating CD16+ monocytes determined by scRNAseq of PBMCs was substantially higher in atherosclerotic patients that died from a cardiovascular cause during 20 years of follow-up compared to survivors from the same study collective, indicating that cellular TRAF expression may predict cardiovascular long-term outcomes.
Conclusion: Here, we present the first cross-species assessment of cellular TRAF3, 4 and 7 expression in murine and human atherosclerosis by utilizing a multiparametric approach to circumvent the lack of viable knockout models. Finally, we provide first evidence that cellular TRAF expression assessed by scRNAseq may add to the clinicians armamentarium for MACE prediction in the future.