Changes in acetyl-CoA mediate Sik3-induced maturation of chondrocytes in endochondral bone formation
Changes in acetyl-CoA mediate Sik3-induced maturation of chondrocytes in endochondral bone formation
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DOI：
10.1016/j.bbrc.2019.06.139
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发表时间：
2019-09-03
影响因子：
3.1
通讯作者：
Tsumaki, Noriyuki
中科院分区：
文献类型：
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作者：
Kosai, Azuma;Horike, Nanao;Tsumaki, Noriyuki
软骨细胞的成熟受到严格调节，以保证适当的软骨内骨形成。尽管最近的研究表明细胞内代谢过程调节细胞的增殖和分化，但人们对代谢物水平的变化如何调节软骨细胞成熟知之甚少。为了确定调节软骨细胞成熟的代谢物，我们对 Sik3 敲除小鼠的软骨细胞进行了代谢组分析，其中软骨细胞成熟延迟。在该模型中，代谢物中乙酰辅酶 A 减少。 Sik3 敲除软骨细胞的免疫组织化学分析表明，磷酸丙酮酸脱氢酶（磷酸-Pdh）（Pdh 的一种失活形式，将丙酮酸转化为乙酰辅酶 A 的酶）和 Pdh 激酶 4（Pdk4）（磷酸化 Pdh）的表达水平增加。用 CPI613 治疗抑制 Pdh 可延迟器官培养中跖骨原始软骨中的软骨细胞成熟。这些结果共同表明乙酰辅酶A水平降低是软骨细胞成熟延迟的原因而不是结果。 Sik3 似乎通过降低 Pdk4 的表达水平来增加乙酰辅酶 A 水平。通过用鱼藤酮处理来阻断 TCA 循环中的 ATP 合成也会延迟器官培养中跖骨原始软骨中的软骨细胞成熟，这表明剥夺乙酰辅酶 A 作为 TCA 循环底物可能是导致成熟延迟的原因。我们发现乙酰辅酶A作为软骨细胞成熟的调节剂，可能有助于理解代谢物控制软骨内骨形成的调节机制。 (C) 2019 年作者。由爱思唯尔公司出版
The maturation of chondrocytes is strictly regulated for proper endochondral bone formation. Although recent studies have revealed that intracellular metabolic processes regulate the proliferation and differentiation of cells, little is known about how changes in metabolite levels regulate chondrocyte maturation. To identify the metabolites which regulate chondrocyte maturation, we performed a metabolome analysis on chondrocytes of Sik3 knockout mice, in which chondrocyte maturation is delayed, Among the metabolites, acetyl-CoA was decreased in this model. Immunohistochemical analysis of the Sik3 knockout chondrocytes indicated that the expression levels of phospho-pyruvate dehydrogenase (phospho-Pdh), an inactivated form of Pdh, which is an enzyme that converts pyruvate to acetylCoA, and of Pdh kinase 4 (Pdk4), which phosphorylates Pdh, were increased. Inhibition of Pdh by treatment with CPI613 delayed chondrocyte maturation in metatarsal primordial cartilage in organ culture. These results collectively suggest that decreasing the acetyl-CoA level is a cause and not result of the delayed chondrocyte maturation. Sik3 appears to increase the acetyl-CoA level by decreasing the expression level of Pdk4. Blocking ATP synthesis in the TCA cycle by treatment with rotenone also delayed chondrocyte maturation in metatarsal primordial cartilage in organ culture, suggesting the possibility that depriving acetyl-CoA as a substrate for the TCA cycle is responsible for the delayed maturation. Our finding of acetyl-CoA as a regulator of chondrocyte maturation could contribute to understanding the regulatory mechanisms controlling endochondral bone formation by metabolites. (C) 2019 The Authors. Published by Elsevier Inc.