Integrated network pharmacology and UHPLC-Q-TOF LC-MS/MS phytochemical profiling demonstrate tilianin-mediated restoration of PDE10A/cAMP/PKA/CREB signaling in an MK-801-induced schizophrenia-like model.

BACKGROUND: Schizophrenia is a complex neuropsychiatric disorder characterized by impairments in cognition, perception, and social behavior. Current antipsychotic medications primarily target dopaminergic signaling but often exhibit limited efficacy in treating negative and cognitive symptoms. Moreover, long-term antipsychotic therapy is frequently associated with clinically relevant adverse effects, including metabolic syndrome and extrapyramidal symptoms (EPS). Phosphodiesterase 10A (PDE10A) has emerged as a promising non-dopaminergic therapeutic target involved in regulating cyclic nucleotide signaling in the striatum. However, several synthetic PDE10A inhibitors have shown safety and tolerability limitations. This study therefore investigated the antipsychotic-like potential of the ethanol extract of Dracocephalum moldavica (EEDM) and its major flavone glycoside, tilianin, in an MK-801-induced schizophrenia-like mouse model and explored the underlying molecular mechanisms.

METHODS: Tilianin content in EEDM was quantified using HPLC, and phytochemical constituents were comprehensively characterized by UHPLC-Q-TOF LC-MS/MS. The inhibitory effect of EEDM and tilianin on PDE10A activity was evaluated using in vitro enzyme assays, supported by molecular docking. Behavioral tests, including the open field test (OFT), acoustic startle response (ASR), novel object recognition, and social interaction test (SIT), were performed in MK-801-induced schizophrenia-like mice. Mechanistic insights were explored through network pharmacology analysis and further validated by analyzing the cAMP/PKA/CREB signaling in the prefrontal cortex using Western blot analysis.

RESULTS: HPLC analysis identified tilianin as the major constituent of EEDM, while UHPLC-Q-TOF LC-MS/MS profiling revealed a diverse phytochemical profile comprising multiple flavonoids and phenolic compounds. Molecular docking predicted stable, high-affinity binding of tilianin to the PDE10A catalytic site (docking score: -11.857 kcal/mol), and this prediction was supported by an enzymatic assay showing PDE10A inhibition by both EEDM (IC50 = 346.6 μg/ml) and tilianin (IC50 = 11.25 μg/ml; 25.20 μM). Tilianin ameliorated MK-801-induced hyperlocomotion, rescued prepulse inhibition (PPI) deficits, and reversed impairments in cognitive and social functions. Network pharmacology identified PDE10A, CREB1, ESR1, and MAPK1 as key hubs modulating synaptic plasticity. Furthermore, tilianin restored the disrupted cAMP/PKA/CREB signaling in the prefrontal cortex.

CONCLUSION: These findings suggest that tilianin may act as a network-informed modulator associated with PDE10A inhibition and downstream neuroplastic signaling, providing a potential mechanistic basis for addressing the limited efficacy of conventional antipsychotic strategies in schizophrenia.