Recent studies have indicated that puerarin treatment improved sucrose preference and depression-like behavior in HFD/CUMS-induced rats by inhibiting toll-like receptor 4 (TLR4)-mediated intestinal mucus barrier dysfunction and neuroinflammation damage through the TLR4/cytosolic phospholipases A2 (cPLA2)/cyclooxygenase-2 (COX-2) pathway [74]. The gene discussed is TLR4; the disease is major depressive disorder.