MAPK8 and major depressive disorder: Lacking CTRP3 exacerbated depression‐type behaviors (e.g., decreased sucrose consumption and locomotor activity), neuronal death, expression of cleaved caspase‐3, and pro‐inflammatory responses by inhibiting p38 and Jun N‐terminal kinase (JNK)/mitogen‐activated protein kinase (MAPK) pathways in a depression mouse model.33