Glycosylation of dentin matrix protein 1 is a novel key element for astrocyte maturation and BBB integrity

Protein & Cell

Min Pan¹  Yuteng Weng¹  Yao Sun¹  Zuolin Wang¹  Bo Jing²  Jie Liu²  Jiping Liu²  Yinan Yao²  Yi Eve Sun²  Chunxue Zhang²  Liqiang Zhou²  Xianjun Liu²  Juehua Yu² 

[1] Department of Oral Implantology, School of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration;Tongji University School of Medicine, Stem Cell Translational Research Center, Tongji Hospital;

关键词: blood-brain barrier;    dentin matrix protein1;    glycosylation;    astrocyte;    cell adhesion;    proteoglycan;   

DOI  :  10.1007/s13238-017-0449-8

来源: DOAJ

【 摘 要 】

Abstract The blood-brain barrier (BBB) is a tight boundary formed between endothelial cells and astrocytes, which separates and protects brain from most pathogens as well as neural toxins in circulation. However, detailed molecular players involved in formation of BBB are not completely known. Dentin matrix protein 1 (DMP1)-proteoglycan (PG), which is known to be involved in mineralization of bones and dentin, is also expressed in soft tissues including brain with unknown functions. In the present study, we reported that DMP1-PG was expressed in brain astrocytes and enriched in BBB units. The only glycosylation site of DMP1 is serine89 (S89) in the N-terminal domain of the protein in mouse. Mutant mice with DMP1 point mutations changing S89 to glycine (S89G), which completely eradicated glycosylation of the protein, demonstrated severe BBB disruption. Another breed of DMP1 mutant mice, which lacked the C-terminal domain of DMP1, manifested normal BBB function. The polarity of S89G-DMP1 astrocytes was disrupted and cell-cell adhesion was loosened. Through a battery of analyses, we found that DMP1 glycosylation was critically required for astrocyte maturation both in vitro and in vivo. S89G-DMP1 mutant astrocytes failed to express aquaporin 4 and had reduced laminin and ZO1 expression, which resulted in disruption of BBB. Interestingly, overexpression of wild-type DMP1-PG in mouse brain driven by the nestin promoter elevated laminin and ZO1 expression beyond wild type levels and could effectively resisted intravenous mannitol-induced BBB reversible opening. Taken together, our study not only revealed a novel element, i.e., DMP1-PG, that regulated BBB formation, but also assigned a new function to DMP1-PG.

【 授权许可】

Unknown