Highly dynamic transcriptional signature of distinct macrophage subsets during sterile inflammation, resolution, and tissue repair

T Varga, R Mounier, A Horvath, S Cuvellier… - The Journal of …, 2016 - journals.aai.org
T Varga, R Mounier, A Horvath, S Cuvellier, F Dumont, S Poliska, H Ardjoune, G Juban…
The Journal of Immunology, 2016journals.aai.org
Macrophage gene expression determines phagocyte responses and effector functions.
Macrophage plasticity has been mainly addressed in in vitro models that do not account for
the environmental complexity observed in vivo. In this study, we show that microarray gene
expression profiling revealed a highly dynamic landscape of transcriptomic changes of Ly6C
pos CX3CR1 lo and Ly6C neg CX3CR1 hi macrophage populations during skeletal muscle
regeneration after a sterile damage. Systematic gene expression analysis revealed that the …
Abstract
Macrophage gene expression determines phagocyte responses and effector functions. Macrophage plasticity has been mainly addressed in in vitro models that do not account for the environmental complexity observed in vivo. In this study, we show that microarray gene expression profiling revealed a highly dynamic landscape of transcriptomic changes of Ly6C pos CX3CR1 lo and Ly6C neg CX3CR1 hi macrophage populations during skeletal muscle regeneration after a sterile damage. Systematic gene expression analysis revealed that the time elapsed, much more than Ly6C status, was correlated with the largest differential gene expression, indicating that the time course of inflammation was the predominant driving force of macrophage gene expression. Moreover, Ly6C pos/Ly6C neg subsets could not have been aligned to canonical M1/M2 profiles. Instead, a combination of analyses suggested the existence of four main features of muscle-derived macrophages specifying important steps of regeneration: 1) infiltrating Ly6C pos macrophages expressed acute-phase proteins and exhibited an inflammatory profile independent of IFN-γ, making them damage-associated macrophages; 2) metabolic changes of macrophages, characterized by a decreased glycolysis and an increased tricarboxylic acid cycle/oxidative pathway, preceded the switch to and sustained their anti-inflammatory profile; 3) Ly6C neg macrophages, originating from skewed Ly6C pos cells, actively proliferated; and 4) later on, restorative Ly6C neg macrophages were characterized by a novel profile, indicative of secretion of molecules involved in intercellular communications, notably matrix-related molecules. These results show the highly dynamic nature of the macrophage response at the molecular level after an acute tissue injury and subsequent repair, and associate a specific signature of macrophages to predictive specialized functions of macrophages at each step of tissue injury/repair.
journals.aai.org