Transcriptional Profiling of Polarized Macrophages using RNA-Sequencing

Adipose tissue macrophages (ATMs) are pivotal regulators for adipose tissue function, specifically contributing to the homeostasis of the adipose niche. Significantly increased ATMs and their altered activation patterns are causal factors to the pathogenesis of adipose tissue inflammation, and subsequently, obesity associated cardiovascular risks, type II diabetes and other metabolic syndromes. Macrophages primarily display an anti-inflammatory M2 status in lean adipose tissues whereas a pro-inflammatory M1 state in adipose tissues of obese individuals. Modulatory networks governing ATMs polarized activation have been investigated but the full picture remains vague. To understand the genome wide signaling networks in controlling ATM polarization, we generated transcriptome profiles from macrophages with various activation statuses- M0, M1 and M2. Among 23400 aligned unique loci from the RNA-sequencing results, around 3500 displayed differential expression pattern during macrophage polarization. The most enriched Gene Ontology terms in the category of KEGG pathways are allograft rejection and Type I diabetes mellitus pathways in M1 macrophages. IFNg was found to be one of the top upstream regulator in M1 playing pivotal role in different functional pathways. In addition, the anti-inflammatory regulator miR-223 was found to be one of top upstream regulator in M2 datasets and playing role in important functional pathways. Understanding of the complex network of interactions among different factors involved in state of polarization of macrophages would be of great advantage in finding solutions to major health issues.