Macrophage Dysfunction in Atherosclerosis and Cardiometabolic Diseases

Summary: Overall This Program Project grant has unveiled key roles for macrophage metabolism, depot- and cue-dependent molecular re-programming and intraorgan communications in cardiometabolic dysfunction. The Program Project team will build upon these discoveries and forge new directions. Macrophages mediate intraorgan communications and, through interorgan communications, macrophages and other bioactive mediators home to and infiltrate distinct sites, such as in the atherosclerotic plaque; in obese adipose tissue; and to be newly explored in this Cycle; in the liver. In cardiometabolic dysfunction, the liver is the recipient of increased endotoxin from the gut; accumulation of lipid from adipose tissue; and increased bioavailability of damage-associated molecular patterns. In each metabolic organ, the tissue-specific niche defines the myriad consequences, such as excess synthesis/deposition of pathological lipids; and recruitment of infiltrating bone marrow-derived immune cells. These delivered stimuli modulate endogenous signaling pathways in resident adipose tissue macrophages and liver Kupffer cells and impart immunometabolic imprints on macrophage subsets in atherosclerosis, obesity and non-alcoholic steatohepatitis (NASH). These concepts are clinically-significant, as atherosclerosis, obesity and NASH are established risk factors for cardiovascular diseases. The Program Project will explore three specific aims: First, Aim 1 (Project 1) will determine the mechanisms by which caloric restriction mediates macrophage intra- and interorgan communications in atherosclerosis, obesity and NASH, and define the impact of LXRα phosphorylation in liver immune cells on NASH-related factors under study in each Project. Second, Aim 2 (Project 2) will probe the mechanisms by which netrin-1 and its receptor network mediate macrophage intra- and interorgan communications in atherosclerosis, obesity and NASH. Third, Aim 3 (Project 3) will probe the mechanisms by which RAGE/DIAPH1 mediates macrophage intra- and interorgan communications in atherosclerosis, obesity and NASH. The Program Project will be supported by three cores: Core A (Administrative, which includes Biostatistics and Bioinformatics); Core B (Pathology and Biochemistry); and Core C (Mouse Breeding and Procedure Core). Collectively, this highly-motivated Program Project team continues to work together synergistically to interrogate novel mechanisms by which macrophage intraorgan and interorgan communications contribute to the mediation and remediation of cardiometabolic disease. Through the employment of state-of-the-art approaches and shared complementary examinations in human tissues and human transcriptome databases, this Program Project will discover new mechanistic insights that lead to therapeutic approaches to quench the exaggerated macrophage accumulation, inflammation and intra/interorgan communications that amplify cardiovascular risk.