FBXO10 prevents chronic unpredictable stress-induced behavioral despair and cognitive impairment through promoting RAGE degradation.

Aims: Depression is one of the leading causes of disability worldwide. The receptor for advanced glycosylation end products (RAGE) is closely related to chronic stress and is a target of F-box protein O10 (FBXO10) which promotes the degradation of RAGE by ubiquitination. Here, we explored the role of FBXO10 and RAGE in chronic unpredictable stress (CUS)-induced behavioral despair, cognitive impairment, neuroinflammation, and the polarization microglia.

Methods: Male C57BL/6 mice with or without infusion of viral in the medial prefrontal cortex (PFC) were subjected to CUS. Then the mice were exposed to forced swim test, sucrose consumption test, novelty-suppressed feeding test, and temporal object recognition task to assess the behavioral despair and cognitive impairment. Inflammatory cytokines and the neurotrophic factor brain-derived neurotrophic factor (BDNF) levels in PFC were assessed by enzyme-linked immunosorbent assay. Immunofluorescence and immunohistochemistry staining were performed to observe the activation and phenotypic transformation of microglia in PFC. LPS-induced cell model was constructed to explore the effect of FBXO10/RAGE axis in the polarization of microglia in vitro.

Results: FBXO10 promoted RAGE degradation by ubiquitination in BV2 cells. FBXO10 protein levels were reduced whereas RAGE protein levels were enhanced in CUS mice. FBXO10 overexpression or RAGE knockdown inhibited proinflammatory cytokine release, promoted BDNF expression, mitigated the depressive-like and cognitive impairment behaviors, and affected the polarization of microglia induced by CUS exposure. FBXO10/RAGE axis promoted the polarization of microglia from the M1 to the M2 phenotype in vitro. Moreover, p38 MAPK and NF-κΒ were identified to be the downstream effect factors for FBXO10/RAGE axis.

Conclusions: FBXO10 administration prevents CUS-induced behavioral despair, cognitive impairment, neuroinflammation, and the polarization of microglia through decreasing the accumulation of RAGE, p38 MAPK, and NF-κΒ, suggesting potential therapeutic strategies for the prevention and treatment of depression.