Distinct Transcriptional Responses across Tissue-Resident Macrophages to Short-Term and Long-Term Metabolic Challenge.

The innate immune system safeguards the organism from both pathogenic and environmental stressors. Also, physiologic levels of nutrients affect organismal and intra-cellular metabolism and challenge the immune system. In the long term, over-nutrition leads to low-grade systemic inflammation. Here, we investigate tissue-resident components of the innate immune system (macrophages) and their response to short- and long-term nutritional challenges. We analyze the transcriptomes of six tissue-resident macrophage populations upon acute feeding and identify adipose tissue macrophages and the IL-1 pathway as early sensors of metabolic changes. Furthermore, by comparing functional responses between macrophage subtypes, we propose a regulatory, anti-inflammatory role of heat shock proteins of the HSP70 family in response to long- and short-term metabolic challenges. Our data provide a resource for assessing the impact of nutrition and over-nutrition on the spectrum of macrophages across tissues with a potential for identification of systemic responses.