PCSK5 and depressive disorder: Chronic social defeat stress (CSDS) causes depression in rodents, and RNA-seq analysis shows that this is associated with promoting the production of proprotein convertase subtilisin/kexin type 5 (Pcsk5) in LHb neurons, which activates the matrix metalloproteinase (MMP) 14-MMP2 pathway and promotes remodeling of the extracellular matrix to produce neuroinflammation [80].