mir-374-5p, mir-379-5p, and mir-503-5p Regulate Proliferation and Hypertrophic Differentiation of Growth Plate Chondrocytes in Male Rats
mir-374-5p, mir-379-5p, and mir-503-5p Regulate Proliferation and Hypertrophic Differentiation of Growth Plate Chondrocytes in Male Rats
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DOI：
10.1210/en.2017-00780
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发表时间：
2018-03-01
期刊：
影响因子：
4.8
通讯作者：
Baron, Jeffrey
中科院分区：
文献类型：
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作者：
Jee, Youn Hee;Wang, Jinhee;Baron, Jeffrey
生长板软骨细胞依次分化形成休止区、增殖区和肥厚区。microRNAs （miRNAs）在生长板中的重要作用先前通过软骨特异性消融Dicer（许多miRNAs的生物发生所必需的酶）揭示。为了鉴定调节PZ软骨细胞向HZ软骨细胞分化的特异性miRNA，我们对幼年大鼠的单个生长板区进行了显微解剖，并使用溶液杂交法和miRNA测序进行了miRNA谱分析。34种mirna在PZ和HZ之间存在差异表达，我们假设PZ中优先表达的一些mirna可能促进增殖并抑制肥厚分化。与这一假设一致，转染这些mirna中的四种抑制剂（mir-369-3p, mir-374-5p， mir-379-5p和mir-503-5p）可降低原发性骺软骨细胞的增殖。其中三种mirna （mir-374-5p、mir-379-5p和mir-503-5p）的抑制剂也增加了与软骨细胞肥厚分化相关的多种基因的表达。接下来，我们假设这些mirna在PZ中的优先表达是由生长板上甲状旁腺激素相关蛋白（PTHrP）浓度梯度驱动的。与这一假设相一致，用甲状旁腺激素(PTH)/PTHrP受体激动剂PTH1-34治疗原发性软骨细胞可增加mir-374-5p、mir-379-5p和mir-503-5p的表达。综上所述，我们的研究结果表明，生长板上的PTHrP浓度梯度诱导了PZ和HZ之间mir-374-5p、mir-379-5p和mir-503-5p的差异表达。在PZ中，这些mirna的高表达水平促进增殖并抑制肥厚分化。在HZ中，这些mirna的下调抑制增殖并促进肥厚分化。
Growth plate chondrocytes undergo sequential differentiation to form the resting zone, the proliferative zone (PZ), and the hypertrophic zone (HZ). The important role of microRNAs (miRNAs) in the growth plate was previously revealed by cartilage-specific ablation of Dicer, an enzyme essential for biogenesis of many miRNAs. To identify specific miRNAs that regulate differentiation of PZ chondrocytes to HZ chondrocytes, we microdissected individual growth plate zones from juvenile rats and performed miRNA profiling using a solution hybridization method and miRNA sequencing. Thirty-four miRNAs were differentially expressed between the PZ and the HZ, and we hypothesized that some of the miRNAs that are preferentially expressed in the PZ may promote proliferation and inhibit hypertrophic differentiation. Consistent with this hypothesis, transfection of inhibitors for four of these miRNAs (mir-369-3p, mir-374-5p, mir-379-5p, and mir-503-5p) decreased proliferation in primary epiphyseal chondrocytes. The inhibitors for three of these miRNAs (mir-374-5p, mir-379-5p, and mir-503-5p) also increased expression of multiple genes that are associated with chondrocyte hypertrophic differentiation. We next hypothesized that preferential expression of these miRNAs in the PZ is driven by the parathyroid hormone-related protein (PTHrP) concentration gradient across the growth plate. Consistent with this hypothesis, treatment of primary chondrocytes with a parathyroid hormone (PTH)/PTHrP receptor agonist, PTH1-34, increased expression of mir-374-5p, mir-379-5p, and mir-503-5p. Taken together, our findings suggest that the PTHrP concentration gradient across the growth plate induces differential expression of mir-374-5p, mir-379-5p, and mir-503-5p between the PZ and the HZ. In the PZ, the higher expression levels of these miRNAs promote proliferation and inhibit hypertrophic differentiation. In the HZ, downregulation of these miRNAs inhibits proliferation and promotes hypertrophic differentiation.