Zaman G, Staines K A, Farquharson C, Newton P T, Dudhia J, Chenu C, Pitsillides A A, Dhoot G K
Department of Comparative Biomedical Sciences, RVC, University of London, London, NW1 OTU, UK.
The Roslin Institute, Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
Histochem Cell Biol. 2016 Jan;145(1):67-79. doi: 10.1007/s00418-015-1365-8. Epub 2015 Oct 14.
SULF1/SULF2 enzymes regulate cell signalling that impacts the growth and differentiation of many tissues. To determine their possible role in cartilage and bone growth or repair, their expression was examined during development and bone fracture healing using RT-PCR and immunochemical analyses. Examination of epiphyseal growth plates revealed differential, inverse patterns of SULF1 and SULF2 expressions, with the former enriched in quiescent and the latter in hypertrophic chondrocyte zones. Markedly higher levels of both SULFs, however, were expressed in osteoblasts actively forming bone when compared with proliferating pre-osteoblasts in the periosteum or the entombed osteocytes which express the lowest levels. The increased expression of Sulf1 and Sulf2 in differentiating osteoblasts was further confirmed by RT-PCR analysis of mRNA levels in rat calvarial osteoblast cultures. SULF1 and SULF2 were expressed in most foetal articular chondrocytes but down-regulated in a larger subset of cells in the post-natal articular cartilage. Unlike adult articular chondrocytes, SULF1/SULF2 expression varied markedly in post-natal hypertrophic chondrocytes in the growth plate, with very high SULF2 expression compared with SULF1 apparent during neonatal growth in both primary and secondary centres of ossification. Similarly, hypertrophic chondrocytes expressed greatly higher levels of SULF2 but not SULF1 during bone fracture healing. SULF2 expression unlike SULF1 also spread to the calcifying matrix around the hypertrophic chondrocytes indicating its possible ligand inhibiting role through HSPG desulphation. Higher levels of SULF2 in both developing and healing bone closely correlated with parallel increases in hedgehog signalling analysed by ptc1 receptor expression.
硫酸酯酶1/硫酸酯酶2（SULF1/SULF2）酶调节细胞信号传导，影响许多组织的生长和分化。为了确定它们在软骨和骨生长或修复中的可能作用，利用逆转录聚合酶链反应（RT-PCR）和免疫化学分析方法检测了它们在发育过程和骨折愈合过程中的表达情况。对骨骺生长板的检查显示，SULF1和SULF2的表达呈差异、相反模式，前者在静止区富集，后者在肥大软骨细胞区富集。然而，与骨膜中增殖的前成骨细胞或表达水平最低的包埋骨细胞相比，在积极形成骨的成骨细胞中，两种硫酸酯酶的表达水平明显更高。通过对大鼠颅骨成骨细胞培养物中mRNA水平的RT-PCR分析，进一步证实了分化中的成骨细胞中Sulf1和Sulf2表达的增加。SULF1和SULF2在大多数胎儿关节软骨细胞中表达，但在出生后关节软骨的较大细胞亚群中表达下调。与成年关节软骨细胞不同，生长板中出生后肥大软骨细胞中SULF1/SULF2的表达有明显差异，在初级和次级骨化中心的新生儿生长期间，与SULF1相比，SULF2的表达非常高。同样，在骨折愈合过程中，肥大软骨细胞中SULF2的表达水平大大高于SULF1。与SULF1不同，SULF2的表达也扩散到肥大软骨细胞周围的钙化基质，表明其可能通过硫酸乙酰肝素（HSPG）去硫酸化发挥配体抑制作用。在发育中和愈合中的骨中，较高水平的SULF2与通过ptc1受体表达分析的刺猬信号通路的平行增加密切相关。
