State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
Cell Prolif. 2021 Dec;54(12):e13156. doi: 10.1111/cpr.13156. Epub 2021 Nov 2.
Previous reports have proposed the importance of signalling and material exchange between cartilage and subchondral bone. However, the specific experimental evidence is still insufficient to support the effect of this interdependent relationship on mutual cell behaviours. In this study, we aimed to investigate cellular lipid metabolism in chondrocytes induced by osteoblasts.
Osteoblast-induced chondrocytes were established in a Transwell chamber. A cholesterol detection kit was used to detect cholesterol contents. RNA sequencing and qPCR were performed to assess changes in mRNA expression. Western blot analysis was performed to detect protein expression. Immunofluorescence staining was conducted to show the cellular distribution of proteins.
Cholesterol levels were significantly decreased in chondrocytes induced by osteoblasts. Osteoblasts reduced cholesterol synthesis in chondrocytes by reducing the expression of a series of synthetases, including Fdft1, Sqle, Lss, Cyp51, Msmo1, Nsdhl, Sc5d, Dhcr24 and Dhcr7. This modulatory process involves Notch1 signalling. The expression of ncstn and hey1, an activator and a specific downstream target of Notch signalling, respectively, were decreased in chondrocytes induced by osteoblasts.
For the first time, we elucidated that communication with osteoblasts reduces cholesterol synthesis in chondrocytes through Notch1 signalling. This result may provide a better understanding of the effect of subchondral bone signalling on chondrocytes.
先前的报告提出了软骨和软骨下骨之间信号传递和物质交换的重要性。然而，具体的实验证据仍然不足以支持这种相互依存关系对细胞相互作用的影响。在本研究中，我们旨在研究成骨细胞诱导的软骨细胞中的细胞脂质代谢。
在 Transwell 小室内建立成骨细胞诱导的软骨细胞。使用胆固醇检测试剂盒检测胆固醇含量。进行 RNA 测序和 qPCR 以评估 mRNA 表达的变化。通过 Western blot 分析检测蛋白表达。通过免疫荧光染色显示蛋白的细胞分布。
成骨细胞诱导的软骨细胞中的胆固醇水平显著降低。成骨细胞通过降低一系列合成酶的表达，包括 Fdft1、Sqle、Lss、Cyp51、Msmo1、Nsdhl、Sc5d、Dhcr24 和 Dhcr7，减少了软骨细胞中的胆固醇合成。这种调节过程涉及 Notch1 信号。成骨细胞诱导的软骨细胞中 Notch1 信号的激活剂 ncstn 和特异性下游靶标 hey1 的表达降低。
我们首次阐明了与成骨细胞的通讯通过 Notch1 信号降低软骨细胞中的胆固醇合成。这一结果可能更好地理解软骨下骨信号对软骨细胞的影响。
