CXCL1 and major depressive disorder: Blockage of NLRP1 inflammasome-driven inflammatory signaling ameliorates depressive-like behaviors of the animals and reserves the up-regulation of hippocampal CXCL1/CXCR2 signaling and the down-regulation of BDNF signaling induced by stress stimuli, suggesting NLRP1 inflammasome is involved in the processes of MDD through regulating CXCL1/CXCR2-BDNF signaling pathway.