Department of Medicine, Laval University, Canada G1V 4G2.
Bone. 2010 Mar;46(3):598-603. doi: 10.1016/j.bone.2009.11.012. Epub 2009 Nov 17.
Paget's disease of bone (PDB) is a common metabolic bone disorder with a significant genetic component. To date, only one gene associated with PDB has been identified, the p62-Sequestosome1 gene (SQSTM1), and more than 20 mutations of this gene have been reported in PDB, the most common being the P392L substitution. In order to search for differentially expressed genes in PDB, we investigated the relative gene expression profile of candidate genes in osteoclast (OCL) cultures from 12 PDB patients and six unmatched healthy controls with known genetic status regarding p62, including healthy carriers of the P392L mutation. We selected 48 OCL-expressed candidate genes that may be involved in relevant pathways of PDB pathogenesis, such as OCL signaling, survival, bone resorption activity, or adhesion. In OCL cultures derived from peripheral blood mononuclear cells, total RNA extraction was performed, followed by real-time PCR experiments. Relative quantification analysis utilized the qBase method where relative expression levels were normalized with respect to a set of reference primer pairs for three housekeeping genes. When compared to non-mutated healthy controls, OCL cultures from PDB patients displayed a significant down-regulation in genes involved in apoptosis (CASP3 and TNFRSF10A), in cell signaling (TNFRSF11A), in the OCL bone resorbing function (ACP5 and CTSK) and in the gene coding for Tau protein (MAPT) (all comparisons, p<0.0001). Comparison of relative gene expression in PDB patients with P392L mutation versus PDB patients without SQSTM1 mutation did not provide significant differential gene expression. However, we observed a non-significant decrease in the expression of several genes such as IL6ST, HIF1A, OSTM1, TNFRSF-10B and -10D, PDK1, MAPT and CASP3 in healthy carriers of the P392L mutation. These results provide important information about the mis-regulated activities of pagetic OCL, and highlight the role of altered apoptosis pathways in these cells. They also suggest that the SQSTM1 P392L mutation plays a role in PDB pathogenesis, even at early preclinical stages in healthy carriers of the P392L mutation.
佩吉特病（PDB）是一种常见的代谢性骨病，具有显著的遗传成分。迄今为止，仅发现一个与 PDB 相关的基因，即 p62-自噬相关蛋白 1 基因（SQSTM1），并且已经在 PDB 中报告了超过 20 种该基因的突变，其中最常见的是 P392L 取代。为了寻找 PDB 中的差异表达基因，我们研究了来自 12 名 PDB 患者和 6 名具有已知 p62 遗传状态的配对健康对照者的破骨细胞（OCL）培养物中的候选基因相对基因表达谱，其中包括 P392L 突变的健康携带者。我们选择了 48 个可能参与 PDB 发病机制相关途径的 OCL 表达候选基因，如 OCL 信号、存活、骨吸收活性或粘附。在源自外周血单核细胞的 OCL 培养物中，进行总 RNA 提取，然后进行实时 PCR 实验。相对定量分析利用 qBase 方法，其中相对表达水平相对于一组用于三个管家基因的参考引物对进行归一化。与非突变的健康对照组相比，来自 PDB 患者的 OCL 培养物中涉及细胞凋亡的基因（CASP3 和 TNFRSF10A）、细胞信号（TNFRSF11A）、OCL 骨吸收功能（ACP5 和 CTSK）和编码 Tau 蛋白的基因（MAPT）表达明显下调（所有比较，p<0.0001）。与 PDB 患者的 SQSTM1 突变相比，与 PDB 患者的 P392L 突变相比，未观察到差异表达基因。然而，我们观察到 P392L 突变的健康携带者中一些基因如 IL6ST、HIF1A、OSTM1、TNFRSF-10B 和 -10D、PDK1、MAPT 和 CASP3 的表达水平降低，但没有统计学意义。这些结果提供了有关 pagetic OCL 中失调活动的重要信息，并强调了细胞凋亡途径改变在这些细胞中的作用。它们还表明，即使在 P392L 突变的健康携带者的早期临床前阶段，SQSTM1 P392L 突变也在 PDB 发病机制中起作用。
