Gut-derived IL-17A via STAT3/RORγt signaling underlies sleep disruption-induced depression: Targeting effects of Schisandrin B therapy.

BACKGROUNDCircadian rhythm disruption and chronic sleep deprivation are increasingly recognized as key contributors to depression, largely through gut-brain axis dysregulation and neuroinflammatory activation. IL-17A, a pro-inflammatory cytokine primarily derived from intestinal Th17 cells, has emerged as a pivotal mediator linking gut immune imbalance to central nervous system dysfunction.

PURPOSEThis study aimed to elucidate the gut-derived IL-17A-STAT3/RORγt signaling mechanism underlying sleep-deprivation-induced depression and to determine whether Schisandrin B, a lignan from Schisandra chinensis, can alleviate depressive phenotypes by restoring gut-brain axis homeostasis.

METHODSClinical analyses of plasma cytokines and metabolites were integrated with a mouse model of sleep-deprivation-induced depression. Behavioral tests, resting-state fMRI, gut microbiota 16S rDNA sequencing, Western blotting, ELISA, and network pharmacology with molecular docking were employed to comprehensively investigate neuroimmune, microbial, and neurofunctional alterations.

RESULTSPatients with circadian rhythm disorder-related depression exhibited elevated IL-17A and systemic inflammatory cytokines, accompanied by metabolic dysregulation. Sleep-deprived mice showed depressive-like behaviors, intestinal barrier disruption, Th17/IL-17A pathway activation, and abnormal RS-fMRI activity in mood-regulating brain regions. Schisandrin B treatment markedly reversed these changes-restoring gut microbial balance, enhancing barrier integrity, suppressing IL-17A-driven inflammation, and normalizing neural function. Mechanistically, Schisandrin B inhibited STAT3 phosphorylation and RORγt expression, while targeting MAPK1 and GSK3β as key regulatory nodes.

CONCLUSIONThis study identifies gut-derived IL-17A-STAT3/RORγt signaling as a mechanistic bridge between sleep deprivation and neuroinflammation, providing direct evidence for the immunological basis of circadian rhythm-related depression. By integrating multi-omics and neuroimaging validation, we demonstrate for the first time that Schisandrin B exerts antidepressant-like effects via coordinated modulation of the gut-brain-immune network. These findings highlight Schisandrin B as a promising natural immunomodulatory candidate for the treatment of mood disorders associated with disrupted circadian rhythms.