Affiliation:
1. Department of Human Anatomy Research Centre for Bone and Stem Cells School of Basic Medical Sciences Key Laboratory for Aging & Disease School of Biomedical Engineering and Informatics Nanjing Medical University Nanjing Jiangsu 211166 China
2. Department of Oral and Maxillofacial Surgery The Affiliated Stomatological Hospital of Nanjing Medical University State Key Laboratory Cultivation Base of Research Prevention and Treatment for Oral Diseases Jiangsu Province Engineering Research Centre of Stomatological Translational Medicine Nanjing Medical University Nanjing Jiangsu 210029 China
3. School of Pharmacy Nanjing Medical University Nanjing Jiangsu 211166 China
Abstract
AbstractWith the increase in the aging population, senile osteoporosis (SOP) has become a major global public health concern. Here, it is found that Prx1 and Bmi‐1 co‐localized in trabecular bone, bone marrow cavity, endosteum, and periosteum. Prx1‐driven Bmi‐1 knockout in bone‐marrow mesenchymal stem cells (BMSCs) reduced bone mass and increased bone marrow adiposity by inhibiting osteoblastic bone formation, promoting osteoclastic bone resorption, downregulating the proliferation and osteogenic differentiation of BMSCs, and upregulating the adipogenic differentiation of BMSCs. However, Prx1‐driven Bmi‐1 overexpression showed a contrasting phenotype to Prx1‐driven Bmi‐1 knockout in BMSCs. Regarding mechanism, Bmi‐1‐RING1B bound to DNMT3A and promoted its ubiquitination and inhibited DNA methylation of Runx2 at the region from 45047012 to 45047313 bp, thus promoting the osteogenic differentiation of BMSCs. Moreover, Bmi‐1‐EZH2 repressed the transcription of Cebpa by promoting H3K27 trimethylation at the promoter region −1605 to −1596 bp, thus inhibiting the adipogenic differentiation of BMSCs. It is also found that Prx1‐driven Bmi‐1 overexpression rescued the SOP induced by Prx1‐driven Bmi‐1 knockout in BMSCs. Thus, Bmi‐1 functioned as a hub protein in the epigenetic regulation of BMSCs differentiation to delay bone aging. The Prx1‐driven Bmi‐1 overexpression in BMSCs can be used as an approach for the translational therapy of SOP.
Funder
National Natural Science Foundation of China
Qinglan Project of Jiangsu Province of China
Natural Science Foundation of Jiangsu Province