Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
J Cell Biochem. 2012 Dec;113(12):3672-80. doi: 10.1002/jcb.24240.
Numerous studies with rodent cells and animal models indicate that noggin inhibits osteogenesis by antagonizing bone morphogenetic proteins (BMPs); however, the effect of noggin on osteogenesis of human cells remains ambiguous. This study aims to examine the effects of noggin suppression on viability and BMP-2-induced osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (MSCs) in vitro. Noggin expression in human MSCs was suppressed by noggin-specific small interfering RNA (siRNA), and viability of human MSCs was determined by measuring the mitochondrial dehydrogenase activity, cellular DNA content and protein amount. The BMP-2-induced osteogenic differentiation of human MSCs was assessed by analyzing the expression levels of several osteoblastic genes, enzymatic alkaline phosphatase (ALP) activity and calcification. Our study showed that noggin suppression significantly decreased human MSC metabolism and DNA content on Days 3 and 6, and decreased total protein amount on Day 14. Noggin suppression also reduced the expression levels of osteoblastic genes, ALP, integrin-binding sialoprotein (IBSP), muscle segment homeobox gene (MSX2), osteocalcin (OC), osteopontin (OPN), and runt-related transcription factor-2 (RUNX2). Significantly decreased enzymatic ALP activity in noggin-suppressed group was evident. Moreover, noggin suppression decreased calcium deposits by BMP-2-induced osteoblasts. Collectively, this study showed that noggin suppression decreased viability and BMP-2-induced osteogenic differentiation of human MSCs, which suggests that noggin is stimulatory to osteogenesis of human MSCs.
许多使用啮齿动物细胞和动物模型的研究表明，noggin 通过拮抗骨形态发生蛋白（BMPs）来抑制成骨作用；然而，noggin 对人细胞成骨作用的影响仍存在争议。本研究旨在体外研究 noggin 抑制对人骨髓间充质干细胞（MSCs）活力和 BMP-2 诱导的成骨分化的影响。通过 noggin 特异性小干扰 RNA（siRNA）抑制人 MSC 中的 noggin 表达，并通过测量线粒体脱氢酶活性、细胞 DNA 含量和蛋白质含量来确定人 MSC 的活力。通过分析几个成骨细胞基因的表达水平、碱性磷酸酶（ALP）活性和钙化来评估 BMP-2 诱导的人 MSC 成骨分化。我们的研究表明，noggin 抑制在第 3 天和第 6 天显著降低了人 MSC 的代谢和 DNA 含量，并在第 14 天降低了总蛋白含量。noggin 抑制还降低了成骨细胞基因、ALP、整合素结合唾液蛋白（IBSP）、肌肉节同源框基因（MSX2）、骨钙素（OC）、骨桥蛋白（OPN）和 runt 相关转录因子-2（RUNX2）的表达水平。在 noggin 抑制组中，明显降低的酶 ALP 活性是明显的。此外，noggin 抑制还减少了 BMP-2 诱导的成骨细胞的钙沉积。总的来说，这项研究表明，noggin 抑制降低了人 MSC 的活力和 BMP-2 诱导的成骨分化，这表明 noggin 对人 MSC 的成骨作用具有刺激作用。
