Peripheral immune cell-derived matrix metalloprotease 8 (MMP8): brain trafficking promotes depression-like behavior

In a study recently published in Nature , Cathomas et al. 1 report that social stress in mice increases the levels of matrix metalloprotease (MMP)8 in circulating immune cells, thereby altering extracellular space (ECS) and neuronal activity, and ultimately social behavior in susceptible animals. Behavioral deficits resembled those from major depressive disorder (MDD) raising the prospect of MMP8 as a new druggable target in tailored treatments.