The Atherosclerosis Core (Core 3; C3) will be led by Dr. Edward Fisher and provide Program Project Grant (PPG) investigators with three complementary approaches for analyzing atherosclerotic lesions, lesion macrophages, and gene expression in myeloid cells and tissues investigated in the projects. First, C3 will provide histological staining, immunohistochemistry, and quantification of atherosclerotic lesions. Second, it will provide laser capture microdissection of macrophages and other types of cells in atherosclerotic lesions for analysis of gene expression changes. Third, C3 will provide expertise in aortic digestion to obtain specific cell compartments to provide samples to the NYU Genomic Technology Center (GTC) for RNA sequencing (RNA- seq) and single cell RNA-seq (scRNA-seq) analyses. These `omic' data will then undergo bioinformatic analyses under Core 1, which will oversee Administration, Data Management, Biostatistics, and Bioinformatics.By providing a central laboratory, C3 offers these services with optimal efficiency and cost- effectiveness, avoiding the need for PPG investigators to maintain the required instrumentation in their own laboratories or use expensive commercial services. By centralizing and standardizing procedures, C3 provides a common set of analytical tools to enable a unified understanding of molecular mechanisms involved in pathophysiologic processes of atherosclerosis and the biology of macrophages and endothelial cells. The Specific Aims of C3 are: 1. To provide comprehensive tissue analysis and quantification of atherosclerotic lesions; 2. To provide laser capture microdissection (LCM) of target cells, primarily macrophages, in atherosclerotic lesions for gene expression studies; 3. To prepare aortic tissue (by digestion and FACS) to provide samples to the GTC for RNA-seq and scRNA-seq (with the resulting data to be analyzed by Core 1).