Inflammation

Abstract

The lecture presented the beneficial intervention of inflammatory processes in response to infectious or other types of aggression. The main families of molecules (" sensors ") capable of inducing such responses were recalled. The respective roles of neutrophils and monocytes/macrophages were discussed. The former, mobile cells, exert a pro-inflammatory action by projecting DNA filaments coated with effector proteins known as NET (neutrophil extra cellular trap), the importance of which has been better understood in recent years. The involvement of polynuclears in the crucial stage of resolving inflammation and the mechanisms involved were presented and discussed.

In recent years, the heterogeneity of monocyte populations has been identified, both in terms of ontogeny (for some, as components of cerebral microglia during embryonic or fetal life) and function. The mechanisms responsible for the mobilization and activation of the various monocyte populations were discussed. The function of a macromolecular entity : the inflammasome, an essential component in the induction of inflammatory responses - in particular the production of the cytokine IL-1 - was highlighted. Inflammation is not a static concept. For example, it has recently been shown that initial activation by microbial molecules induces a pre-activation state in monocytic cells through metabolic and epigenetic modification of hematopoietic precursors. This form of " memory " of inflammation is likely to participate in the development of chronic inflammatory pathologies. Finally, the lecture analyzed the state of knowledge of the mechanisms of resolution of inflammation, defects in which are also suspected to contribute to chronic inflammatory pathologies.