GLS and major depressive disorder: Selective allosteric GLS1 inhibitors, such as bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl)ethyl sulfide (BPTES) and CB-839 (Telaglenastat), have mild GI side effects [44], but their poor brain penetration [45] poses a significant limitation to their clinical application for neuroinflammatory diseases such as depression.