In the chronic unpredictable mild stress (CUMS) mouse model, human umbilical cord mesenchymal stromal cells reduced neuronal complement C3 receptors and thereby attenuated NLRP3 activation-induced neuroinflammation and ultimately ameliorated CUMS-induced depression-like behavior (Li J. et al., 2021). This evidence concerns the gene NLRP3 and major depressive disorder.