Impact of Hyperinsulinemic Priming on Macrophage Activation
MetadataShow full item record
The impact of hyperinsulinemia on adipose tissue inflammation has been studied for decades in order to try and obtain a better understanding of the underlying effects of cardiovascular diseases and diabetes mellitus. Despite the medical interest in this subject and how adipose tissue macrophages are central to the development of adipose tissue inflammation, how these cells directly respond to the pathological dosages of insulin has yet to be proved. Inside adipose tissue macrophages (ATMs), despite the expression of the molecules mediating insulin signaling in other cell types, it is relatively unknown what direct impact insulin has on these ATMs who contribute to both systemic and adipose tissue inflammation and insulin resistance. In this study, the direct impacts of hyperinsulinemia are addressed by subjecting bone marrow derived macrophages (BMDMs) to a state of hyperinsulinemia in order to examine the direct impact that insulin has on macrophage activation through the comparison of the expression of genes related to macrophage activation by quantitative real time-polymerase chain reaction (qRT-PCR). Next the importance of prolonged exposure to pathological insulin dosages with regards to classical macrophage activation are examined by comparing the gene expression of BMDMs that were subjected to a 24 hour insulin priming period to that of BMDMs that were first exposed to insulin at the time of macrophage activation. Then, in order to understand how insulin enhances classical macrophage response, the expressions of Toll-Like Receptor genes are examined. Finally the results from BioPlex analysis are used to determine the cell signaling protein expression and phosphorylation through which insulin achieves this impact on the macrophage cell. The results showed that prolonged exposure to pathological insulin levels results in an increase in the expression of genes associated with classical, proinflammatory macrophage activation, and this effect does not appear to be the result of an increase in Toll-Like Receptors that respond to proinflammatory stimuli. Lastly an enhanced decrease in the phosphorylation ratio of the Protein Kinase B pathway suggests that insulin resistance applies to macrophages in a manner similar to other insulin targets in the body. This project proves how critical the understanding of insulin-regulated macrophage responses is to studying hyperinsulinemia-related metabolic disorders such as diabetes.
Jones, Benjamin T (2015). Impact of Hyperinsulinemic Priming on Macrophage Activation. Undergraduate Research Scholars Program. Available electronically from