Ryynänen Jussi, Kriebitzsch Carsten, Meyer Mark B, Janssens Iris, Pike J Wesley, Verlinden Lieve, Verstuyf Annemieke
Clinical and Experimental Endocrinology, KULeuven, Herestraat 49, Bus 902, 3000 Leuven, Belgium.
Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA.
J Steroid Biochem Mol Biol. 2017 Oct;173:185-193. doi: 10.1016/j.jsbmb.2017.02.005. Epub 2017 Feb 9.
The vitamin D endocrine system is essential for calcium metabolism and skeletal integrity. 1,25-dihydroxyvitamin D [1,25(OH)D] regulates bone mineral homeostasis and acts directly on osteoblasts. In the present study we characterized the transcriptional regulation of the class 3 semaphorin (Sema3) gene family by 1,25(OH)D in osteoblastic cells. Class 3 semaphorins are secreted proteins that regulate cell growth, morphology and migration, and were recently shown to be involved in bone homeostasis. In ST2, MC3T3-E1 and primary calvarial osteoblast cell cultures we found that all members of the Sema3 gene family were expressed, and that Sema3e and Sema3f were the most strongly induced 1,25(OH)D target genes among the studied cell types. In addition, transcription of Sema3b and Sema3c was upregulated, whereas Sema3d and Sema3g was downregulated by 1,25(OH)D in different osteoblastic cells. Chromatin immunoprecipitation analysis linked to DNA sequencing (ChIP-seq analysis) revealed the presence of the vitamin D receptor at multiple genomic loci in the proximity of Sema3 genes, demonstrating that the genes are primary 1,25(OH)D targets. Furthermore, we showed that recombinant SEMA3E and SEMA3F protein were able to inhibit osteoblast proliferation. However, recombinant SEMA3s did not affect ST2 cell migration. The expression of class 3 semaphorins in osteoblasts together with their regulation by 1,25(OH)D suggests that these genes, involved in the regulation of bone homeostasis, are additional mediators for 1,25(OH)D signaling in osteoblasts.
维生素D内分泌系统对钙代谢和骨骼完整性至关重要。1,25-二羟基维生素D [1,25(OH)D] 调节骨矿物质稳态,并直接作用于成骨细胞。在本研究中,我们对成骨细胞中1,25(OH)D对3类信号素(Sema3)基因家族的转录调控进行了表征。3类信号素是分泌蛋白,可调节细胞生长、形态和迁移,最近被证明参与骨稳态。在ST2、MC3T3-E1和原代颅骨成骨细胞培养物中,我们发现Sema3基因家族的所有成员均有表达,并且在研究的细胞类型中,Sema3e和Sema3f是1,25(OH)D诱导最强的靶基因。此外,在不同的成骨细胞中,1,25(OH)D上调了Sema3b和Sema3c的转录,而下调了Sema3d和Sema3g的转录。与DNA测序相关的染色质免疫沉淀分析(ChIP-seq分析)显示,维生素D受体存在于Sema3基因附近的多个基因组位点,表明这些基因是1,25(OH)D的主要靶基因。此外,我们表明重组SEMA3E和SEMA3F蛋白能够抑制成骨细胞增殖。然而,重组SEMA3s不影响ST2细胞迁移。成骨细胞中3类信号素的表达及其受1,25(OH)D的调控表明,这些参与骨稳态调节的基因是1,25(OH)D在成骨细胞中信号传导的额外介质。