L'influence du stress psychologique sur la réponse de l'hôte à une infection par le virus de la grippe : focus sur les macrophages pulmonaires

Abstract

Since November 16, 2019, our world has been plunged into a psychosis related to the emergence of a novel respiratory virus. Many pandemics have flouted our daily lives over the last century, and the SARS-COV2 virus will not be the last. In addition to potential viral emergence, humans are confronted, on a daily basis, to various sources of stress. Numerous studies have proven the profound effects of stress on the entire body and especially on the immune system. The host laboratory (GIGA Immunophysiology) pays particular attention to the influence of stress on the immune cells that populate the lungs infected by the Influenza A virus. Recent discoveries from the same laboratory have revealed a previously unknown macrophage population that expresses a marker of neutrophils, Ly6G. This macrophage acts in the early phase of tissue repair, allowing optimal differentiation of pneumocytes 2 into pneumocytes 1 in the perilesional alveolar areas, thereby licensing alveolar repair. In this study, we investigated whether exposing mice to psychological stress (using the WAS model) in addition to infecting them with the virus could modify the immune response, particulary the kinetics of Ly6G+ macrophages and, consequently impact lung tissue repair compared to mice that were only infected. First of all, our results showed that stress induces significant modifications in the progenitors of these Ly6G+ macrophages in both the bone marrow and blood. Furthermore, stress strongly reduced the number of Ly6G+ macrophages throughout the duration of their presence in the lungs. Finally, the analysis of epithelial cells during the pulmonary tissue repair phase revealed a significant reduction of type 1 and type 2 pneumocytes in the cohort of stressed mice compared to the cohort of stress-free mice, indicating a non-optimal tissue repair of the lungs in the presence of stress. These preliminary results pave the way to a doctoral project I will undertake in the host laboratory.