Department of Cell Biology, Institute of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan.
Int J Mol Sci. 2020 Sep 11;21(18):6665. doi: 10.3390/ijms21186665.
Hedgehog (Hh) signaling is highly conserved among species and plays indispensable roles in various developmental processes. There are three Hh members in mammals; one of them, Indian hedgehog (Ihh), is expressed in prehypertrophic and hypertrophic chondrocytes during endochondral ossification. Based on mouse genetic studies, three major functions of Ihh have been proposed: (1) Regulation of chondrocyte differentiation via a negative feedback loop formed together with parathyroid hormone-related protein (PTHrP), (2) promotion of chondrocyte proliferation, and (3) specification of bone-forming osteoblasts. Gli transcription factors mediate the major aspect of Hh signaling in this context. Gli3 has dominant roles in the growth plate chondrocytes, whereas Gli1, Gli2, and Gli3 collectively mediate biological functions of Hh signaling in osteoblast specification. Recent studies have also highlighted postnatal roles of the signaling in maintenance and repair of skeletal tissues.
刺猬 (Hh) 信号在物种间高度保守，在各种发育过程中发挥不可或缺的作用。哺乳动物中有 3 种 Hh 成员；其中之一的印度刺猬 (Ihh) 在软骨内骨化过程中表达于预肥大和肥大软骨细胞中。基于小鼠遗传研究，提出了 Ihh 的三个主要功能：（1）通过与甲状旁腺激素相关蛋白 (PTHrP) 形成的负反馈环来调节软骨细胞分化，（2）促进软骨细胞增殖，以及（3）特异性骨形成成骨细胞。Gli 转录因子在这种情况下介导 Hh 信号的主要方面。Gli3 在生长板软骨细胞中起主要作用，而 Gli1、Gli2 和 Gli3 共同介导 Hh 信号在成骨细胞特化中的生物学功能。最近的研究还强调了信号在维持和修复骨骼组织中的出生后作用。
