Dullard/Ctdnep1 Regulates Endochondral Ossification via Suppression of TGF-β Signaling
Dullard/Ctdnep1 Regulates Endochondral Ossification via Suppression of TGF-β Signaling
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DOI：
10.1002/jbmr.2343
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发表时间：
2015-02-01
影响因子：
6.2
通讯作者：
Noda, Masaki
中科院分区：
文献类型：
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作者：
Hayata, Tadayoshi;Ezura, Yoichi;Noda, Masaki
转化生长因子（Transforming growth factor，TGF）信号转导在骨骼发育过程中起着关键作用，其过度信号转导导致结缔组织遗传性疾病，包括马凡氏综合征和肢端发育不良。然而，骨骼发生中过度TGF-β信号传导的潜在预防机制仍不清楚。我们以前报道过，Dullard/Ctdnep 1编码一种小磷酸酶，通过抑制骨形态发生蛋白（BMP）信号传导，在出生后维持肾单位是必需的。出乎意料的是，我们发现Dullard参与了软骨内骨化过程中TGF-β信号的抑制。条件Dullard缺陷小鼠的四肢和胸骨间充质Prx 1-Cre显示受损的生长和骨化的骨骼元素，导致出生后的死亡。Dullard在早期软骨凝聚和生长板软骨细胞中表达。新生Dullard突变小鼠胫骨生长板显示增殖和肥大软骨细胞层减少。胸骨软骨原基畸形，迟发性肥大。微团培养实验表明，Dullard缺陷增强早期软骨凝聚和分化，但抑制矿化肥大软骨细胞分化，这是逆转治疗与TGF-I型受体激酶阻断剂LY-364947。Dullard缺乏诱导微团培养中磷酸化Smad 2/3和总Smad 2/3蛋白水平上调，而Smad 2/3 mRNA水平不增加，表明Dullard可能影响Smad 2/3蛋白的稳定性。磷酸化Smad 2/3水平也上调软骨膜和肥大的软骨细胞在Dullard缺陷的胚胎。在Dullard缺陷的原代软骨细胞培养物中，对TGF-信号传导的反应在晚期而非早期时间点增强。此外，LY-364947的围产期给药改善了体内胸骨畸形。因此，我们确定Dullard作为一个新的负调节TGF-β信号转导内软骨骨化。(c)2014年美国骨与矿物质研究学会。
Transforming growth factor (TGF)- signaling plays critical roles during skeletal development and its excessive signaling causes genetic diseases of connective tissues including Marfan syndrome and acromelic dysplasia. However, the mechanisms underlying prevention of excessive TGF- signaling in skeletogenesis remain unclear. We previously reported that Dullard/Ctdnep1 encoding a small phosphatase is required for nephron maintenance after birth through suppression of bone morphogenetic protein (BMP) signaling. Unexpectedly, we found that Dullard is involved in suppression of TGF- signaling during endochondral ossification. Conditional Dullard-deficient mice in the limb and sternum mesenchyme by Prx1-Cre displayed the impaired growth and ossification of skeletal elements leading to postnatal lethality. Dullard was expressed in early cartilage condensations and later in growth plate chondrocytes. The tibia growth plate of newborn Dullard mutant mice showed reduction of the proliferative and hypertrophic chondrocyte layers. The sternum showed deformity of cartilage primordia and delayed hypertrophy. Micromass culture experiments revealed that Dullard deficiency enhanced early cartilage condensation and differentiation, but suppressed mineralized hypertrophic chondrocyte differentiation, which was reversed by treatment with TGF- type I receptor kinase blocker LY-364947. Dullard deficiency induced upregulation of protein levels of both phospho-Smad2/3 and total Smad2/3 in micromass cultures without increase of Smad2/3 mRNA levels, suggesting that Dullard may affect Smad2/3 protein stability. The phospho-Smad2/3 level was also upregulated in perichondrium and hypertrophic chondrocytes in Dullard-deficient embryos. Response to TGF- signaling was enhanced in Dullard-deficient primary chondrocyte cultures at late, but not early, time point. Moreover, perinatal administration of LY-364947 ameliorated the sternum deformity in vivo. Thus, we identified Dullard as a new negative regulator of TGF- signaling in endochondral ossification. (c) 2014 American Society for Bone and Mineral Research.