STAT3 and major depressive disorder: Activation of the HMGB1/signal transducer and activator of transcription 3 (STAT3)/nuclear factor-kappa B (NF-κB) p65 axis in microglia located in the medial prefrontal cortex (mPFC) facilitates microglial activation and autophagy, contributing to the pathophysiology and progression of depression (Xu et al., 2023).