Regulation of type II collagen synthesis during osteoarthritis by prolyl-4-hydroxylases -: Possible influence of low oxygen levels
Regulation of type II collagen synthesis during osteoarthritis by prolyl-4-hydroxylases -: Possible influence of low oxygen levels
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DOI：
10.2353/ajpath.2006.050738
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发表时间：
2006-08-01
影响因子：
6
通讯作者：
Pfander, David
中科院分区：
文献类型：
--
作者：
Grimmer, Claudia;Balbus, Nadine;Pfander, David
骨关节炎（OA）软骨细胞代谢活跃，显示H型胶原合成增加。在这里，我们通过免疫组织化学和聚合酶链反应表明，与健康软骨相比，OA关节软骨细胞;表现出II型胶原蛋白脯氨酰-4-羟化酶（胶原蛋白三螺旋形成中的关键酶）的体内合成增加。原代人关节软骨细胞暴露于1%的氧气增强了天然H型胶原蛋白和稳定的缺氧诱导因子-la（HEF-1 α）的积累。这种作用通过添加HIF-1抑制剂2-甲氧基乙烯基吡咯烷酮而消除。对这些培养物的mRNA进行实时聚合酶链反应分析，发现脯氨酰-4-羟化酶（P4 HA 1，相似于2倍; P4 HA 2，相似于2.3倍）和经典HIF-1靶基因（葡萄糖转运蛋白-1，相似于2.1倍;磷酸甘油酸激酶-1，相似于2.2倍）的α亚基的转录水平均增加。缺氧软骨细胞的处理;与2-甲氧基乙醇一起降低HIT-1的转录活性和胶原蛋白脯氨酰-4-羟化酶α（H）亚基的合成，并在较小程度上降低α（I）亚基的合成。然而，H型胶原蛋白（Col 2A 1）和脯氨酰-4-羟化酶β亚基（P4 HB）的mRNA水平在1%氧气下仅显示出适度的变化。从这些结果和我们在体内的数据，我们推断，除了增加Col 2A 1 mRNA的表达OA软骨细胞，加速翻译后修饰过程可能有助于增加合成和积累的H型胶原在OA和实验缺氧。
Osteoarthritic (OA) chondrocytes are metabolically active, displaying increased synthesis of type H collagen. Here, we show by immunohistochemistry and polymerase chain reaction that in comparison with healthy cartilage, OA articular chondrocytes; exhibit increased in vivo synthesis of collagen prolyl-4-hydroxylase type II, a pivotal enzyme in collagen triple helix formation. Exposure of primary human articular chondrocytes to 1% oxygen enhanced accumulation of native type H collagen and stabilized hypoxia-inducible factor-la (HEF-1 alpha). This effect was abolished by addition of the HIF-1 inhibitor 2-methoxyestradiol. Real-time polymerase chain reaction analyses of mRNAs from these cultures revealed increased transcript levels of both alpha-subunits of prolyl-4-hydroxylase (P4HA1, similar to 2-fold; P4HA2, similar to 2.3-fold) and of classical HIF-1 target genes (glucosetransporter-1, similar to 2.1-fold; phosphoglyceratekinase-1, similar to 2.2-fold). Treatment of hypoxic chondrocytes; with 2-methoxyestradiol reduced transcriptional activity of HIT-1 and synthesis of a(H), and to a lesser extent alpha(I), subunits of collagen prolyl-4-hydroxylases. mRNA levels of type H collagen (Col2A1) and the beta-subunit (P4HB) of prolyl-4-hydroxylase, however, displayed only modest changes at 1% oxygen. From these results and our in vivo data, we inferred that besides increased Col2A1 mRNA expression by OA chondrocytes, accelerated posttranslational modification processes might contribute to the increased synthesis and accumulation of type H collagen during OA and experimental hypoxia.