Impaired nuclear translocation of glucocorticoid receptor (GR) has been implicated in hippocampal vulnerability in Alzheimer's disease (AD), yet the molecular basis of this defect remains poorly under Show more
Impaired nuclear translocation of glucocorticoid receptor (GR) has been implicated in hippocampal vulnerability in Alzheimer's disease (AD), yet the molecular basis of this defect remains poorly understood. This study identified Huntingtin-associated protein 1 (Hap1) as a critical regulator of GR nuclear translocation in the hippocampus. Specifically, Hap1 expression progressively declined in the hippocampus of APP/PS1 mice with advancing age and pathological burden. Hippocampal Hap1 knockdown induced pronounced cognitive deficits and synaptic deterioration, as indicated by reduced dendritic arborization, decreased spine density, impaired long-term potentiation, and exacerbated amyloid-β deposition. Mechanistic analyses showed that Hap1 deficiency increased GR ubiquitination and proteasomal degradation and, more importantly, disrupted ligand-dependent GR translocation to the nucleus, thereby attenuating GR-dependent brain-derived neurotrophic factor transcription. In parallel, Hap1 knockdown elevated corticosterone concentration and induced depression-like behavior, consistent with hypothalamic-pituitary-adrenal axis dysregulation. Collectively, these findings establish defective GR nuclear trafficking driven by loss of Hap1 function as a key pathomechanism linking intracellular transport failure to synaptic dysfunction in AD and highlight Hap1 as a potential therapeutic target. Show less
Inhye Park, Jung-Eun Lee, Minji Kim+5 more · 2026 · Phytomedicine : international journal of phytotherapy and phytopharmacology · Elsevier · added 2026-04-24
Depression imposes significant social, economic, and health burdens worldwide. Although phlorotannin-rich extract from Ecklonia cava (PS) and its active compound dieckol (DK) exhibit various biologica Show more
Depression imposes significant social, economic, and health burdens worldwide. Although phlorotannin-rich extract from Ecklonia cava (PS) and its active compound dieckol (DK) exhibit various biological activities, their antidepressant- and anxiolytic-like effects and underlying mechanisms remain unclear. This study investigated the antidepressant- and anxiolytic-like potential of PS and DK in a corticosterone (CORT)-induced mouse model of depression and anxiety, focusing on glucocorticoid receptor (GR) signaling. CORT-treated mice were orally administered PS or DK, and behavioral tests were performed to assess depressive- and anxiety-like behaviors. PS composition was analyzed using LC-MS/MS. Molecular docking predicted the binding of PS components to GR. GR nuclear translocation, target gene expression, and downstream signaling were examined using behavioral, molecular, and computational approaches. PS alleviated CORT-induced depressive- and anxiety-like behaviors, accompanied by reduced GR nuclear translocation, suppression of Mkp-1, and restoration of ERK-CREB-BDNF signaling. Molecular docking analysis predicted strong binding of DK to the GR ligand-binding domain. Consistently, DK reduced GR nuclear translocation and GRE binding, downregulated GR target genes (Mkp-1, Sgk-1, Fkbp5, and Bdnf), and restored ERK-CREB-BDNF signaling. In vivo, DK also improved CORT-induced behavioral deficits and normalized HPA axis activity and neurotransmitter levels. Collectively, our results suggest that DK, a major bioactive phlorotannin from E. cava, exerts antidepressant- and anxiolytic-like effects in association with modulation antagonism of GR signaling, highlighting its therapeutic potential as a natural GR-modulating agent for stress-related mood disorders. Show less