Igarashi Mamoru, Sakamoto Koji, Nagaoka Isao
Department of Host Defense and Biochemical Research, Graduate School of Medicine, Juntendo University, Tokyo 113-8421, Japan.
Int J Mol Med. 2017 Feb;39(2):472-478. doi: 10.3892/ijmm.2016.2842. Epub 2016 Dec 28.
Glucosamine (GlcN) has been widely used to treat osteoarthritis (OA) in humans. However, the effects of GlcN on genes related to cartilage metabolism are still unknown. In the present study, to elucidate the chondroprotective action of GlcN on OA, we examined the effects of GlcN (0.1-10 mM) on the expression of the sirtuin (SIRT) genes as well as type II collagen and matrix metalloproteinases (MMPs) using a human chondrocyte cell line SW 1353. SW 1353 cells were incubated in the absence or presence of GlcN. RT-PCR analyses revealed that GlcN markedly increased the mRNA expression of type II collagen (COL2A1). By contrast, the levels of MMP-1 and MMP-9 mRNA were only slightly increased by GlcN. Furthermore, western blot analyses revealed that GlcN significantly increased the protein level of COL2A1. Importantly, GlcN enhanced the mRNA expression and protein level of SIRT1, an upstream-regulating gene of COL2A1. Moreover, a SIRT1 inhibitor suppressed GlcN-induced COL2A1 gene expression. Together these observations suggest that GlcN enhances the mRNA expression and protein level of SIRT1 and its downstream gene COL2A1 in chondrocytes, thereby possibly exhibiting chondroprotective action on OA.
氨基葡萄糖（GlcN）已被广泛用于治疗人类骨关节炎（OA）。然而，GlcN对软骨代谢相关基因的影响仍不清楚。在本研究中，为了阐明GlcN对OA的软骨保护作用，我们使用人软骨细胞系SW 1353研究了GlcN（0.1 - 10 mM）对沉默调节蛋白（SIRT）基因以及II型胶原蛋白和基质金属蛋白酶（MMPs）表达的影响。SW 1353细胞在有无GlcN的情况下进行培养。逆转录聚合酶链反应（RT-PCR）分析显示，GlcN显著增加了II型胶原蛋白（COL2A1）的mRNA表达。相比之下，GlcN仅轻微增加了MMP - 1和MMP - 9 mRNA的水平。此外，蛋白质印迹分析显示，GlcN显著增加了COL2A1的蛋白质水平。重要的是，GlcN增强了COL2A1的上游调节基因SIRT1的mRNA表达和蛋白质水平。此外，一种SIRT1抑制剂抑制了GlcN诱导的COL2A1基因表达。这些观察结果共同表明，GlcN增强了软骨细胞中SIRT1及其下游基因COL2A1的mRNA表达和蛋白质水平，从而可能对OA发挥软骨保护作用。
