CCL2 and major depressive disorder: Previously, we found that oligodendrocytes could regulate neuronal activities and controlled food intake by its lactate production.[30] For depression, as mentioned above, a few small molecules produced from oligodendrocytes have been implicated in the pathology of depression.[18] In our study, after Ninj2 ablation, among the TNFα downstream cytokines, Ccl2 was the most significantly induced gene in oligodendrocytes.