GJA1 and major depressive disorder: Two proteins expressed on astrocytes, connexin 30 (Cx30) and Cx43, have been linked to the pathogenesis of depression.162 Gap junctions that enable communication between astrocytes are formed by the membrane proteins Cx30 and Cx43.163 Chronic unpredictable stress (CUS) and acute stress both specifically reduce the expression of the gap junction-forming proteins Cx30 and Cx43,164 and the integrity of the BBB is weakened in mice lacking Cx30 and Cx43.165