Stomatological Hospital, Southern Medical University, Guangzhou, 510280, China.
Department of Stomatology, The Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510630, China.
Stem Cell Res Ther. 2022 Aug 13;13(1):417. doi: 10.1186/s13287-022-03093-7.
Periodontal ligament stem cells (PDLSCs) are the ideal seed cells for periodontal tissue regeneration. It is well established that persistent inflammation significantly impairs the osteogenic differentiation capability of PDLSCs. Therefore, maintaining PDLSC osteogenic potential under the inflammatory microenvironment is important for treating bone loss in periodontitis. The aim of our study was to explore the potential role of circular RNA BIRC6 (circBIRC6) in regulating osteogenic differentiation of PDLSCs in the inflammatory conditions.
Alkaline phosphatase staining, Alizarin Red staining, quantitative real-time polymerase chain reaction, western blotting and immunofluorescence staining were used to evaluated the effects of circBIRC6 on the osteogenic differentiation of PDLSCs. RNA pull-down and luciferase assays were performed to explore the interaction between circBIRC6 and miR-543. Then, the downstream signaling pathway affected by circBIRC6/miR-543 axis was further investigated.
The expression level of circBIRC6 was higher in PDLSCs exposed to inflammatory stimulus and in periodontitis tissues compared to the respective controls. Downregulation of circBIRC6 enhanced the osteogenic potential of PDLSCs under the inflammatory conditions, and upregulation of circBIRC6 led to opposite findings. Mechanistically, we found that circBIRC6 modulated PDLSC osteogenic differentiation through sponging miR-543. More importantly, we have demonstrated that circBIRC6/miR-543 axis regulated the mineralization capacity of PDLSCs via PTEN/PI3K/AKT/mTOR signaling pathway in the inflammatory microenvironment.
In summary, the expression of miR-543 is significantly increased following circBIRC6 downregulation, leading to inhibition of PTEN and subsequently activation of PI3K/AKT/mTOR signaling pathway. Therefore, targeting circBIRC6 might represent a potential therapeutic strategy for improving bone loss in periodontitis.
牙周膜干细胞（PDLSCs）是牙周组织再生的理想种子细胞。持续的炎症显著损害 PDLSCs 的成骨分化能力，这一点已得到充分证实。因此，在炎症微环境下维持 PDLSC 的成骨潜能对于治疗牙周炎中的骨丢失至关重要。本研究旨在探讨环状 RNA BIRC6（circBIRC6）在调节牙周膜干细胞在炎症条件下成骨分化中的潜在作用。
采用碱性磷酸酶染色、茜素红染色、实时定量聚合酶链反应、Western blot 和免疫荧光染色来评估 circBIRC6 对 PDLSCs 成骨分化的影响。采用 RNA 下拉和荧光素酶测定来探索 circBIRC6 与 miR-543 之间的相互作用。然后，进一步研究了 circBIRC6/miR-543 轴影响的下游信号通路。
与相应对照相比，暴露于炎症刺激的 PDLSCs 和牙周炎组织中的 circBIRC6 表达水平更高。circBIRC6 下调增强了炎症条件下 PDLSCs 的成骨潜能，而上调 circBIRC6 则产生相反的结果。机制上，我们发现 circBIRC6 通过海绵吸附 miR-543 调节 PDLSC 成骨分化。更重要的是，我们已经证明，circBIRC6/miR-543 轴通过炎症微环境中的 PTEN/PI3K/AKT/mTOR 信号通路调节 PDLSCs 的矿化能力。
总之，circBIRC6 下调后 miR-543 的表达显著增加，导致 PTEN 抑制，随后激活 PI3K/AKT/mTOR 信号通路。因此，靶向 circBIRC6 可能代表改善牙周炎中骨丢失的一种潜在治疗策略。
