Over the last decade,a growing body of evidence has indicated that vitamin D is not only crucial in maintaining calcium-phosphorus homeostasis and bone density,but also implicated in the regulation of immune system and the maintenance of the normal function of central nervous system.A variety of neuropsychiatric disorders such as multiple sclerosis,Alzheimer's disease,Parkinson's disease,schizophrenia,and depression are suggested to be associated with vitamin D deficiency and immune activation.In this review,we summarize the recent key findings concerning the effect of vitamin D on neuroimmmune modulation and its potential role in those neuropsychiatric disorders.

Objective To explore the relationship between vitamin D and depression and the effects of chronic unpredictable mild stress (CUMS) plus sertraline on vitamin D metabolism in rat brain.Methods Male SD rats were randomly divided into normal control group,normal control + sertraline group,CUMS group and CUMS+sertraline group.CUMS was used to build the animal model of depression.After chronic exposure to CUMS or sertraline (8 mg·kg-1·d-1) for 6 weeks,behavioral response (sucrose preference test) and vitamin D metabolism in the prefrontal cortex were analyzed.Results Compared with normal control group,6 weeks of CUMS procedure induced the rats to a depression-like state,decreased weight and sucrose preference,and increased the expression of enzymes involved in vitamin D activation and catabolism (CYP27B1 and CYP24A1,respectively) and vitamin D receptor (VDR) in rat prefrontal cortex.As compared with CUMS group,CYP27B1,CYP24A1 and VDR were significantly decreased in CUMS+sertraline group (P<0.01 or P<0.05).Conclusion CUMS activates vitamin D signaling in the brain of the animal models of depression,while sertraline alleviates depressive behavior and relieves stress-induced activation of vitamin D signaling,indicating that vitamin D signaling may be involved in the stress-induced depression.