Versican/PG-M Assembles Hyaluronan into Extracellular Matrix and Inhibits CD44-mediated Signaling toward Premature Senescence in Embryonic Fibroblasts*
Versican/PG-M Assembles Hyaluronan into Extracellular Matrix and Inhibits CD44-mediated Signaling toward Premature Senescence in Embryonic Fibroblasts*
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DOI：
10.1074/jbc.m806927200
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发表时间：
2009-03
影响因子：
4.8
通讯作者：
Keittisak Suwan;Kanyamas Choocheep;S. Hatano;P. Kongtawelert;K. Kimata;H. Watanabe
中科院分区：
文献类型：
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作者：
Keittisak Suwan;Kanyamas Choocheep;S. Hatano;P. Kongtawelert;K. Kimata;H. Watanabe
Versican/PG-M是细胞外基质的一种大的硫酸软骨素蛋白聚糖，其在由A、B和B′亚结构域组成的N-末端G1结构域与透明质酸相互作用。最近，我们产生了敲入小鼠Cspg 2 Δ3/Δ3，其多功能蛋白聚糖在没有A亚结构域的情况下具有降低的透明质酸（HA）结合亲和力，从而表现出多功能蛋白聚糖在细胞外基质中的沉积减少。在这里，我们表明Cspg 2 Δ3/Δ3成纤维细胞在20代内增殖更慢并获得衰老。而野生型成纤维细胞的细胞外基质表现出透明质酸和多功能蛋白聚糖的网络结构，Cspg 2 Δ3/Δ3成纤维细胞的细胞外基质表现出多功能蛋白聚糖和HA的1035%和1085%沉积，而没有这样的结构。Cspg 2 Δ3/Δ3成纤维细胞显示ERK 1/2磷酸化和衰老标记物p53、p21和p16表达的显著增加。用透明质酸酶和外源性透明质酸处理野生型成纤维细胞增强ERK 1/2磷酸化，用阻断HA-CD 44相互作用的抗CD 44抗体处理抑制磷酸化。这些结果表明，多功能蛋白聚糖是涉及透明质酸的基质组装所必需的，并且减少的多功能蛋白聚糖沉积增加了与CD 44相互作用的游离透明质酸片段，并增加了ERK 1/2的磷酸化，导致细胞衰老。
Versican/PG-M is a large chondroitin sulfate proteoglycan of the extracellular matrix which interacts with hyaluronan at the N-terminal G1 domain, composed of A, B, and B′ subdomains. Recently, we generated knock-in mice Cspg2Δ3/Δ3, whose versican, without the A subdomain, has decreased hyaluronan (HA) binding affinity, thereby exhibiting reduced deposition of versican in the extracellular matrix. Here, we show that the Cspg2Δ3/Δ3 fibroblasts within 20 passages proliferate more slowly and acquire senescence. Whereas the extracellular matrix of the wild type fibroblasts exhibited a network structure of hyaluronan and versican, that of the Cspg2Δ3/Δ3 fibroblasts exhibited ∼35 and ∼85% deposition of versican and HA, without such a structure. The Cspg2Δ3/Δ3 fibroblasts showed a substantial increase of ERK1/2 phosphorylation and expression of senescence markers p53, p21, and p16. Treatment of wild type fibroblasts with hyaluronidase and exogenous hyaluronan enhanced ERK1/2 phosphorylation, and treatment with an anti-CD44 antibody that blocks HA-CD44 interaction inhibited the phosphorylation. These results demonstrate that versican is essential for matrix assembly involving hyaluronan and that diminished versican deposition increases free hyaluronan fragments that interact with CD44 and increase phosphorylation of ERK1/2, leading to cellular senescence.