Identification of the Transcription Factors of CD200R1 and Its Potential Roles in Parkinson’s Disease

BackgroundNeuroinflammation is known to be involved in the pathogenesis of Parkinson's disease (PD). Abnormal activation of microglia plays a key role in this pathological process. CD200R1 is a membrane glycoprotein primarily expressed in microglia in central nervous system responsible for transducing signaling maintaining microglia in stationary status. Our previous studies have demonstrated the dysregulation of CD200R1 and its involvement in PD pathogenesis. The binding of transcription factors with promoter regions is the basic and essential step for the regulation of gene expression. However, little is known about the human CD200R1 promoter region and the mechanism of the dysregulated expression of CD200R1 in PD. MethodsLuciferase reporter system was initially employed to identify the core region of CD200R1 promoter and figure out its potential transcription factors. Subsequently, we investigated the interaction adopting electrophoretic mobility shift assay and chromatin immunoprecipitation assay. The regulatory function of the detected transcription factors were further proved through its down-regulation and overexpression. We then collected the peripheral blood mononuclear cells from both PD patients and their healthy counterparts with matched age and sex to evaluate whether consistent results existed under clinical setting. Ultimately, the mouse model was established through knocking-out the identified transcription factor and its role in neuroinflammation and pathogenesis of PD was explored. ResultsWe defined that the core promoter region of CD200R was located within -482 to -146 bp upstream of the translation initiation site (TIS). In addition, we demonstrated that NFKB1 directly bound to the CD200R1 core promoter region and regulated its transcriptional activity. Besides, the expression of NFKB1 and CD200R1 was significantly correlated in human peripheral blood mononuclear cells and knocking down NFKB1 significantly reduced CD200R1 expression. Moreover, both NFKB1 and CD200R1 were significantly downregulated in samples from PD patients. Furthermore, NFKB1-/- mice exhibited exacerbated microglia activation and dopaminergic neuron loss after MPTP treatment. ConclusionOur study provided novel understanding of the transcriptional regulation of CD200R1 and its role in microglia homeostasis in the pathogenesis of PD.