Journal of Periodontal Research · Sep 30, 2021

Sirtuin 3 deficiency exacerbates age-related periodontal disease

By Chen J, Zhang Y, Gao J et al.

BACKGROUND: Sirtuin 3 (SIRT3), a mitochondrial NAD⁺ -dependent deacetylase, has received much attention for its effect on metabolism and aging. However, the role of SIRT3 in periodontal disease remains unknown. OBJECTIVE: This study aimed to investigate the functional role of SIRT3 in age-related periodontal disease and underlying mechanisms. METHODS: Sixteen mice were randomly assigned into four groups: the young wild type (WT), the aged WT, the young SIRT3-knockout (KO), and the aged SIRT3-KO. SIRT3 and cyclophilin D (CypD) expression and protein lysine acetylation levels in alveolar bones were detected by western blot. The bone architecture and the distance of CEJ-ABC were assessed using micro-CT and HE staining. The osteoclast number was observed through tartrate-resistant acid phosphatase (TRAP) staining. Mitochondrial morphology in SIRT3 knockdown MC3T3-E1 osteoblastic cells was analyzed by Immunofluorescence staining. In gingival tissues, the NAD⁺ /NADH ratio was measured, and oxidative stress was detected by MitoSOX staining, HO-1 staining, and MnSOD expression. Mitochondrial biogenesis was measured by PGC-1α expression and oxygen consumption rate (OCR). RESULTS: In parallel with the imbalanced NAD⁺ /NADH ratio, the SIRT3 expression was significantly decreased in the alveolar bones of the aged mice, accompanied by a global elevation of protein acetylation levels. The aged SIRT3-KO group showed the highest rate of bone resorption and the largest number of TRAP-positive osteoclasts among the four groups. Moreover, the reactive oxygen species level was up-regulated in the young and the aged SIRT3-KO groups. SIRT3 deficiency promoted mitochondrial fission and increased the CypD expression. Furthermore, the lack of SIRT3 reduced the PGC-1α expression in gingival tissues and exhibited a significant reduction in maximal OCR. CONCLUSION: Reduced SIRT3 abundance contributes to aged-related periodontal disease via the exacerbation of oxidative stress and mitochondrial dysfunction.

doi.org/10.1111/jre.12930Open accessPubMed 34591326Mechanisms