Gene expression profile of cardiac macrophages at different timepoints after myocardial infarction

Myocardial infarction (MI) causes sterile inflammation, which is characterized by recruitment and activation of innate and adaptive immune system cells. We have delineated the temporal dynamics of immune cell accumulation following MI by flow cytometry. Macrophages were numerically the predominant cells infiltrating the infarcted myocardium, increasing in number over the first week post-MI. Macrophages are functionally heterogeneous, and can be classified into M1 and M2 macrophages, respectively, based on surface-marker expression. M1 macrophages dominated at 1-3 days post-MI, whereas M2 macrophages represented the predominant macrophage subset after 5 days. We used microarrays to examine the gene expression profiles of the macrophages sorted from the hearts at different timepoints after MI. We identified the kinetics of gene expression of cardiac macrophage after MI. To examine the expression profile of cardiac macrophages after MI, CD11b+F4/80+Ly-6G- macrophages were sorted and pooled from the hearts (Sham operation, Day1 after MI, Day3 after MI, Day7 after MI, Day14 after MI), followed by RNA extraction and microarrays.