SIRT5 overexpression enhanced of bone marrow mesenchymal stem cells (BMSCs) and improved fracture healing in a rat model.
Increased alkaline phosphatase activity and mineralization were observed with SIRT5 overexpression in BMSCs.
SIRT5 overexpression upregulated osteogenic markers including osteopontin, runt-related transcription factor 2, osterix, and BMP2.
SIRT5 knockdown inhibited osteogenic differentiation processes in BMSCs.
SIRT5 was identified as a regulator of BMP2 , impacting its stability and function.
In a rat tibial fracture model, SIRT5 overexpression led to significant improvements in bone volume fraction, trabecular number, and thickness.
Simplified
BACKGROUND: Bone marrow mesenchymal stem cells (BMSCs) play a crucial role in bone repair and regeneration. The sirtuin family member sirtuin 5 (SIRT5) has been implicated in various cellular processes, including the regulation of . This study aimed to investigate the role of SIRT5 in osteogenic differentiation of BMSCs and its impact on fracture healing.
METHODS: BMSCs were characterized and induced to undergo osteogenic and adipogenic differentiation. The effects of SIRT5 modulation on osteogenic differentiation were assessed through alkaline phosphatase (ALP) staining, Alizarin Red S (ARS) staining, and osteogenic genes expression analysis. The role of SIRT5 in regulating bone morphogenetic protein 2 (BMP2) and stability was explored using Western blot, immunoprecipitation, and co-immunoprecipitation. A rat tibial fracture model was used to evaluate the in vivo effects of SIRT5 and BMP2 modulation on fracture healing, assessed by Micro-CT and histological analysis.
RESULTS: SIRT5 overexpression enhanced osteogenic differentiation of BMSCs, as evidenced by increased ALP activity and mineralization. It also upregulated the expression of osteogenic markers such as osteopontin (OPN), runt-related transcription factor 2 (RUNX2), osterix (OSX), and BMP2. Conversely, SIRT5 knockdown inhibited these processes. Mechanistically, SIRT5 was found to regulate BMP2 succinylation, affecting its stability and function. In vivo, overexpression of SIRT5 in a rat tibial fracture model significantly improved bone volume fraction, trabecular number, and thickness, while reducing trabecular separation. The beneficial effects of SIRT5 overexpression were counteracted by BMP2 knockdown, highlighting the importance of BMP2 in mediating SIRT5's actions on bone healing.
CONCLUSION: SIRT5 promotes osteogenic differentiation of BMSCs and enhances fracture healing by modulating BMP2 succinylation. These findings suggest that SIRT5 could be a potential therapeutic target for the treatment of bone fractures and other skeletal disorders.
Key numbers
3×
Increase in activity
activity measured post-osteogenic induction.
3 of 6 parameters
Bone healing improvement
Micro-CT analysis of tibial fracture healing.
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Declarations. Ethics approval and consent to participate: The animal study was approved by the Experimental Animal Welfare Ethics Committee of Beijing MDKN (code: MDKN-2024-246). All animal experiments should comply with the ARRIVE guidelines. All methods were carried out in accordance with relevant guidelines and regulations.The original source of the human cells (ATCC) has confirmed that there was initial ethical approval for collection of human cells, and that the donors had signed informed consent. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.
