Department of Orthodontics, Peking University School and Hospital of Stomatology, 22 Zhongguancun Avenue South, Haidian District, Beijing, 100081, People's Republic of China.
Department of Stomatology, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China.
Stem Cell Res Ther. 2022 Jun 3;13(1):229. doi: 10.1186/s13287-022-02897-x.
A series of biochemical responses, including hypoxia and aseptic inflammation, occur in periodontal ligament cells (PDLCs) during periodontal tissue remodeling of orthodontic tooth movement (OTM). However, the role of long non-coding RNA (lncRNA) in these responses is still largely unknown. We investigated the role of the lncRNA SNHG8 in hypoxic and inflammatory responses during OTM and explored the underlying mechanisms.
The expression pattern of SNHG8, and hypoxic and inflammatory responses under compressive force were analyzed by qRT-PCR, immunohistochemistry, and western blotting, in vivo and in vitro. The effect of overexpression or knockdown of SNHG8 on the nuclear factor-kappaB (NF-κB) pathway was evaluated. RNA sequencing was performed for mechanistic analysis. The interaction between SNHG8 and hypoxia-inducible factor (HIF)-1α was studied using catRAPID, RNA immunoprecipitation, and RNA pulldown assays. The effect of the SNHG8-HIF-1α interaction on the NF-κB pathway was determined by western blotting.
The NF-κB pathway was activated, and HIF-1α release was stabilized, in PDLCs under compressive force as well as in OTM model rats. The SNHG8 level markedly decreased both in vivo and in vitro. Overexpression of SNHG8 decreased the expression levels of inflammatory cytokines, the phosphorylation of p65, and the degradation of IκBα in PDLCs, whereas knockdown of SNHG8 reversed these effects. Mechanically, RNA sequencing showed that differentially expressed genes were enriched in cellular response to hypoxia after SNHG8 overexpression. SNHG8 binds to HIF-1α, thus preventing HIF-1 from activating downstream genes, including those related to the NF-κB pathway.
SNHG8 binds to HIF-1α. During OTM, the expression of SNHG8 dramatically decreased, releasing free functional HIF-1α and activating the downstream NF-κB pathway. These data suggest a novel lncRNA-regulated mechanism during periodontal tissue remodeling in OTM.
在正畸牙齿移动（OTM）过程中牙周组织重塑期间，牙周韧带细胞（PDLC）中会发生一系列生化反应，包括缺氧和无菌性炎症。然而，长链非编码 RNA（lncRNA）在这些反应中的作用在很大程度上仍然未知。我们研究了 lncRNA SNHG8 在 OTM 期间缺氧和炎症反应中的作用，并探讨了潜在的机制。
通过 qRT-PCR、免疫组织化学和 Western blot，在体内和体外分析 SNHG8 的表达模式以及在压力下的缺氧和炎症反应。评估过表达或敲低 SNHG8 对核因子-κB（NF-κB）通路的影响。进行 RNA 测序以进行机制分析。使用 catRAPID、RNA 免疫沉淀和 RNA 下拉测定研究 SNHG8 与缺氧诱导因子（HIF）-1α之间的相互作用。通过 Western blot 确定 SNHG8-HIF-1α 相互作用对 NF-κB 通路的影响。
在 PDLC 中以及在 OTM 模型大鼠中，NF-κB 通路被激活，并且 HIF-1α的释放得到稳定。体内和体外 SNHG8 水平明显降低。SNHG8 的过表达降低了 PDLC 中炎症细胞因子的表达水平、p65 的磷酸化和 IκBα 的降解，而 SNHG8 的敲低则逆转了这些作用。在机制上，RNA 测序表明，SNHG8 过表达后差异表达的基因在细胞对缺氧的反应中富集。SNHG8 与 HIF-1α 结合，从而防止 HIF-1 激活下游基因，包括与 NF-κB 通路相关的基因。
SNHG8 与 HIF-1α 结合。在 OTM 期间，SNHG8 的表达显著降低，释放出游离的功能性 HIF-1α，激活下游的 NF-κB 通路。这些数据表明，在 OTM 过程中牙周组织重塑期间存在一种新的 lncRNA 调节机制。
