CXCL2 and major depressive disorder: CXCL2, also recognized as macrophage inflammatory protein-2 alpha (MIP-2 α), growth-regulated protein beta (GRO-β), and growth oncogene-2 (Gro-2), is a small chemokine expressed in various cells, such as microglia, astrocytes, and neurons and plays an important role in inflammation [41] and depression [42].