​​​​​EFFECTS OF PSILOCYBIN ON DAMPS-MEDIATED STERILE INFLAMMATION IN 3D NEURAL SPHEROIDS

Psilocybin, a serotonergic psychedelic, has shown promising antidepressant effects, particularly in treatment-resistant depression. However, its mechanisms remain unclear. The pathophysiology of depression is multifactorial, involving dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis impaired neuroplasticity, and neuroinflammation, including sterile inflammation mediated by damage-associated molecular patterns (DAMPs). This study investigated the effects of psilocybin on DAMPs-mediated sterile inflammation using a 3D neural spheroid model exposed to the synthetic glucocorticoid dexamethasone, which mimics stress-induced neuroplasticity deficits. Antidepressant- and anxiolytic-like effects of psilocybin were evaluated in mice using the open field test (OFT) and tail suspension test (TST). To explore mechanisms, 3D neural spheroids were treated with dexamethasone (100 µM) followed by psilocybin (0.1, 1, or 10 µM). BDNF and DAMPs-related inflammatory markers were measured at protein and mRNA levels using biochemical assays. In mouse behavioral tests, a single dose of psilocybin (1 mg/kg) produced significant anxiolytic-effects and antidepressant-like effects at 7 days post-administration (all p<0.05). In 3D neural spheroids treated with dexamethasone, BDNF expression was significantly reduced (p=0.009), while levels of DAMPs-related inflammatory markers, including HMGB1 (p=0.031), S100B (p=0.033), phosphorylated NF-κB (p=0.007), NLRP3 (p=0.041), TNF-α (all p<0.01), and IL-1β (p=0.003), were markedly elevated. Psilocybin treatment significantly restored BDNF expression (p=0.011) and suppressed the upregulation of these inflammatory markers (all p<0.05). Psilocybin exerts antidepressant- and anxiolytic-like effects in vivo and modulates DAMPs-mediated neuroinflammatory responses in a 3D neural spheroid model. This anti-inflammatory effect may serve as one of the mechanisms mediating the antidepressant effects of psilocybin.