BMP-1-induced GBA1 nuclear accumulation provokes CCN2 mRNA expression via importin-β-mediated nucleocytoplasmic pathway

by Selleckchem | Aug 03 2023

Bone morphogenetic protein (BMP)-1 is expressed by odontoblasts in the dentin-pulp complex. Although the functional effects of BMP-1 on the maturation of various preforms of proteins and enzymes involved in initiating mineralization have been widely observed, how BMP-1 affects cellular molecules remains unknown. We performed a comprehensive analysis of BMP-1-altered glycome profiles and subsequent assays to identify the target glycoproteins in human dental pulp cells (hDPCs) by a glycomic approach. In the presence of BMP-1, a lectin microarray analysis and lectin-probed blotting showed that α2,6-sialylation was significantly attenuated in insoluble fractions from hDPCs. Six proteins were identified by a mass spectrometry analysis of α2,6-sialylated glycoproteins purified using a lectin column. Among them, glucosylceramidase (GBA1) was found to accumulate in the nuclei of hDPCs in the presence of BMP-1. Moreover, BMP-1-induced cellular communication network factor (CCN) 2 expression, which is well known as the osteogenesis/chondrogenesis marker, was significantly suppressed in the cells transfected with GBA1 siRNA. Furthermore, importazole, a potent inhibitor of importin-β-mediated nuclear import significantly suppressed BMP-1-induced GBA1 nuclear accumulation and BMP-1-induced CCN2 mRNA expression, respectively. Thus, BMP-1 facilitates the accumulation of GBA1 in the nucleus through the reduction of α2,6-sialic acid, which potentially contributes to the transcriptional regulation of the CCN2 gene via importin-β-mediated nuclear import pathway in hDPCs. Our results offer new insights into the role of the BMP-1-GBA1-CCN2 axis in the development, tissue remodeling, and pathology of dental/craniofacial diseases.

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The passage you provided describes a study that investigated the effects of bone morphogenetic protein-1 (BMP-1) on glycoproteins in human dental pulp cells (hDPCs) and its potential implications for dental and craniofacial diseases. Here is a breakdown of the key findings and implications of the study:

1. Expression of BMP-1 by odontoblasts: BMP-1 is expressed by odontoblasts in the dentin-pulp complex. Odontoblasts are cells responsible for the formation of dentin, which is a mineralized tissue in teeth.

2. BMP-1 and glycome profiles: The study aimed to understand how BMP-1 affects glycoproteins in hDPCs. Glycoproteins are proteins that have attached carbohydrate molecules. Analysis of glycome profiles revealed that the presence of BMP-1 led to a significant reduction in α2,6-sialylation, a specific type of carbohydrate modification, in insoluble fractions of hDPCs.

3. Identification of target glycoproteins: Through mass spectrometry analysis, the researchers identified six glycoproteins that were α2,6-sialylated and affected by BMP-1.

4. GBA1 and nuclear accumulation: One of the identified glycoproteins was glucosylceramidase (GBA1), which was found to accumulate in the nuclei of hDPCs when BMP-1 was present. This suggests that BMP-1 facilitates the nuclear accumulation of GBA1.

5. Role of GBA1 in CCN2 expression: The study found that BMP-1-induced cellular communication network factor 2 (CCN2) expression, a marker of osteogenesis and chondrogenesis, was significantly suppressed in hDPCs when GBA1 expression was silenced using small interfering RNA (siRNA). This implies that GBA1 plays a role in the regulation of CCN2 expression.

6. Involvement of importin-β-mediated nuclear import: Importazole, a potent inhibitor of importin-β-mediated nuclear import, was used in the study. It was found that importazole suppressed BMP-1-induced nuclear accumulation of GBA1 and CCN2 mRNA expression. This suggests that the importin-β-mediated nuclear import pathway is involved in the regulation of GBA1 and CCN2 by BMP-1 in hDPCs.

7. Implications for dental/craniofacial diseases: The findings of this study provide new insights into the role of the BMP-1-GBA1-CCN2 axis in the development, tissue remodeling, and pathology of dental and craniofacial diseases. Further research in this area may lead to a better understanding of the molecular mechanisms involved in these diseases and potential therapeutic targets.

Overall, this study suggests that BMP-1 influences glycoprotein profiles in hDPCs, leading to the nuclear accumulation of GBA1 and the regulation of CCN2 expression. These findings contribute to our understanding of the molecular processes involved in dental and craniofacial diseases and open up avenues for future research and potential therapeutic interventions.