C/EBPbeta Promotes transition from proliferation to hypertrophic differentiation of chondrocytes through transactivation of p57.
C/EBPbeta Promotes transition from proliferation to hypertrophic differentiation of chondrocytes through transactivation of p57.
复制标题
DOI：
10.1371/journal.pone.0004543
复制
发表时间：
2009
期刊：
影响因子：
3.7
通讯作者：
Kawaguchi H
中科院分区：
文献类型：
--
作者：
Hirata M;Kugimiya F;Fukai A;Ohba S;Kawamura N;Ogasawara T;Kawasaki Y;Saito T;Yano F;Ikeda T;Nakamura K;Chung UI;Kawaguchi H
尽管软骨细胞从增殖到肥厚分化的转变是生理骨骼生长和骨关节炎等病理疾病中软骨内成骨的关键步骤，但其潜在机制仍是一个谜。本研究探讨了转录因子CCAAT/增强子结合蛋白β (C/EBPβ)在软骨细胞软骨内成骨过程中的作用。纯合缺乏C/EBPβ (C/EBPβ−/−)的小鼠胚胎在生长板软骨中表现出侏儒症，增生带延长，软骨细胞肥大延迟。在原代C/EBPβ - / -软骨细胞培养中，细胞增殖增强，肥厚分化受到抑制。相反，C/EBPβ逆转录病毒在软骨细胞中的过表达抑制了细胞增殖，增强了细胞肥大，提示C/EBPβ阻滞了细胞周期。事实上，DNA细胞周期直方图显示，C/EBPβ过表达导致了G0/G1部分细胞的积累。在细胞周期因子中，微阵列和实时RT-PCR分析发现周期蛋白依赖性激酶抑制剂p57Kip2是C/EBPβ的转录靶点。p57Kip2与C/EBPβ共定位于小鼠生长板增生晚期和增生性软骨细胞中，并因C/EBPβ缺乏而降低。荧光素酶报告子和电泳迁移率转移实验鉴定了p57Kip2启动子中C/EBPβ的核心响应元件，该元件位于−150和−130 bp之间，包含假定的C/EBP基元。siRNA敲低p57Kip2抑制C/ ebp β诱导的软骨细胞肥大。最后，我们通过诱导野生型成年小鼠和C/EBPβ+/−仔鼠膝关节不稳定建立实验性骨关节炎模型，C/EBPβ不足引起关节软骨破坏的抵抗。C/EBPβ可转激活p57Kip2，促进软骨内成骨过程中软骨细胞从增殖向肥厚分化的转变，提示C/EBPβ-p57Kip2信号可能是生长迟缓和骨关节炎等骨骼疾病的治疗靶点。
Although transition from proliferation to hypertrophic differentiation of chondrocytes is a crucial step for endochondral ossification in physiological skeletal growth and pathological disorders like osteoarthritis, the underlying mechanism remains an enigma. This study investigated the role of the transcription factor CCAAT/enhancer-binding protein β (C/EBPβ) in chondrocytes during endochondral ossification. Mouse embryos with homozygous deficiency in C/EBPβ (C/EBPβ−/−) exhibited dwarfism with elongated proliferative zone and delayed chondrocyte hypertrophy in the growth plate cartilage. In the cultures of primary C/EBPβ−/− chondrocytes, cell proliferation was enhanced while hypertrophic differentiation was suppressed. Contrarily, retroviral overexpression of C/EBPβ in chondrocytes suppressed the proliferation and enhanced the hypertrophy, suggesting the cell cycle arrest by C/EBPβ. In fact, a DNA cell cycle histogram revealed that the C/EBPβ overexpression caused accumulation of cells in the G0/G1 fraction. Among cell cycle factors, microarray and real-time RT-PCR analyses have identified the cyclin-dependent kinase inhibitor p57Kip2 as the transcriptional target of C/EBPβ. p57Kip2 was co-localized with C/EBPβ in late proliferative and pre-hypertrophic chondrocytes of the mouse growth plate, which was decreased by the C/EBPβ deficiency. Luciferase-reporter and electrophoretic mobility shift assays identified the core responsive element of C/EBPβ in the p57Kip2 promoter between −150 and −130 bp region containing a putative C/EBP motif. The knockdown of p57Kip2 by the siRNA inhibited the C/EBPβ-induced chondrocyte hypertrophy. Finally, when we created the experimental osteoarthritis model by inducing instability in the knee joints of adult mice of wild-type and C/EBPβ+/− littermates, the C/EBPβ insufficiency caused resistance to joint cartilage destruction. C/EBPβ transactivates p57Kip2 to promote transition from proliferation to hypertrophic differentiation of chondrocytes during endochondral ossification, suggesting that the C/EBPβ-p57Kip2 signal would be a therapeutic target of skeletal disorders like growth retardation and osteoarthritis.
登录
查看更多内容
影响因子：
4
作者：
Komori, T
通讯作者：
Komori, T
影响因子：
2.7
作者：
Guo, J;Chung, UI;Kronenberg, HM
通讯作者：
Kronenberg, HM
影响因子：
10.5
作者：
LIN, FT;LANE, MD
通讯作者：
LANE, MD
影响因子：
10.5
作者：
DESCOMBES, P;CHOJKIER, M;SCHIBLER, U
通讯作者：
SCHIBLER, U
影响因子：
10.5
作者：
LANDSCHULZ, WH;JOHNSON, PF;MCKNIGHT, SL
通讯作者：
MCKNIGHT, SL