Astroglial Connexin 43 sets the blood brain barrier immune quiescence. Mus musculus

In the brain, a unique homeostatic equilibrium strictly controls immune reactions. In healthy conditions, the immune system poorly communicates with the central nervous system (CNS), immune cell migration across the blood brain barrier (BBB) is kept at a very low level and the unique CNS microenvironment strictly restricts immune reactions. Here, we identified the astroglial gap junction protein Connexin 43 has a new actor of this homeostasis. We showed that genetic inactivation of astroglial Cx43 in the mouse induces expression of a specific set of chemokines and endothelial adhesion molecules leading to neutrophils, macrophages, B and T lymphocytes and mature plasmocytes infiltration at the BBB, and to the development of antigen presentation-related mechanisms, in sterile conditions. Thus, astroglial Cx43 by decreasing the expression of leukocytes adhesion and migration mediators, promotes the immune quiescence of the BBB Overall design: Comparison of 3 months-old Cx43 deleted mice against two distinct WT genetic background