Graduate Student Department of Fundamental Biosciences, Shiga University of Medical Science Otsu-shi, Japan
【Background】To understand the early inflammatory processes that leads to cardiac pathology in KD, we induced KD-like coronary arteritis in mice using FK565, a ligand for nucleotide-binding oligomerization domain containing protein 1 (Nod1). 【Method】Mice were primed by intraperitoneal injection of lipopolysaccharide (LPS) on day 0, and then were injected subcutaneously with FK565 on days 1 and 4. On day 7, the mice were euthanized and the hearts were perfused and dissected. 【Result】Microarray analysis of the aortic root of the mice injected with FK565 (FK565 mice) implied that CD8+ T cells or natural killer (NK) cells were involved in the development of coronary arteritis. To determine which cell subset is primarily involved in arteritis development, we injected FK565 into Rag2-deficient mice, which lack T and B cells but not NK cells, and found that these mice developed typical coronary arteritis, suggesting that CD8+ T cells were dispensable for coronary arteritis development. Flow cytometry analysis of heart cells confirmed that NK cells were infiltrated in the heart of FK565 mice. Furthermore, the depletion of NK cells by injecting anti-asialo GM1 antibody abrogated the development of coronary arteritis in FK565 mice, indicating a role for NK cells in inducing coronary inflammation. Heart-infiltrating NK cells in FK565 mice expressed KLRG1, an NK cell activation marker, and granzyme B. 【Conclusion】Activated NK cells infiltrating in the heart expressed CX3CR1 and contributed to the development of coronary arteritis in KD. The results suggest that activated NK cells infiltrate from the peripheral blood to the heart in the acute phase of KD.
