RFX1‐mediated CCN3 induction that may support chondrocyte survival under starved conditions
RFX1‐mediated CCN3 induction that may support chondrocyte survival under starved conditions
复制标题
DOI：
10.1002/jcp.30348
复制
发表时间：
2021-03
影响因子：
5.6
通讯作者：
Mizukawa Tomomi;Takashi Nishida;Sho Akashi;Kazumi Kawata;Sumire Kikuchi;Harumi Kawaki;M. Takigawa;H. Kamioka;S. Kubota
中科院分区：
文献类型：
--
作者：
Mizukawa Tomomi;Takashi Nishida;Sho Akashi;Kazumi Kawata;Sumire Kikuchi;Harumi Kawaki;M. Takigawa;H. Kamioka;S. Kubota
细胞通讯网络因子（CCN）家族成员是一种多功能的细胞外基质蛋白，可以调控和整合细胞外信号。在我们以前的研究中，我们发现了三个可能受能量代谢调节的CCN家族成员。在这项研究中，我们证实了CCN 2和CCN 3是人类软骨细胞中糖酵解严格调控的唯一成员。有趣的是，CCN 3在各种受损的糖酵解条件下被诱导。在两种具有不同表型的乳腺癌细胞系中也观察到这种CCN 3诱导，表明CCN 3在细胞代谢中的基本作用。报告基因分析表明，在近端启动子区域的增强子介导的转录调控。作为计算机模拟分析的结果，我们将与X-box 1（RFX 1）结合的调节因子指定为通过糖酵解受损介导转录激活的候选因子。事实上，糖酵解的抑制诱导RFX 1的表达，RFX 1沉默通过受损的糖酵解使CCN 3的诱导无效。随后用抗CCN 3抗体进行的实验表明，CCN 3支持糖酵解受损的软骨细胞的存活。与体外的这些发现一致，体内证实了发育中的骺软骨的深部区域中的软骨细胞产生丰富的CCN 3，所述深部区域远离滑液。我们目前的研究发现，RFX 1是在细胞饥饿时能够诱导CCN 3的介质，这可能最终有助于软骨细胞保持其活力，即使在能量供应短缺的情况下。
Cellular communication network factor (CCN) family members are multifunctional matricellular proteins that manipulate and integrate extracellular signals. In our previous studies investigating the role of CCN family members in cellular metabolism, we found three members that might be under the regulation of energy metabolism. In this study, we confirmed that CCN2 and CCN3 are the only members that are tightly regulated by glycolysis in human chondrocytic cells. Interestingly, CCN3 was induced under a variety of impaired glycolytic conditions. This CCN3 induction was also observed in two breast cancer cell lines with a distinct phenotype, suggesting a basic role of CCN3 in cellular metabolism. Reporter gene assays indicated a transcriptional regulation mediated by an enhancer in the proximal promoter region. As a result of analyses in silico, we specified regulatory factor binding to the X‐box 1 (RFX1) as a candidate that mediated the transcriptional activation by impaired glycolysis. Indeed, the inhibition of glycolysis induced the expression of RFX1, and RFX1 silencing nullified the CCN3 induction by impaired glycolysis. Subsequent experiments with an anti‐CCN3 antibody indicated that CCN3 supported the survival of chondrocytes under impaired glycolysis. Consistent with these findings in vitro, abundant CCN3 production by chondrocytes in the deep zones of developing epiphysial cartilage, which are located far away from the synovial fluid, was confirmed in vivo. Our present study uncovered that RFX1 is the mediator that enables CCN3 induction upon cellular starvation, which may eventually assist chondrocytes in retaining their viability, even when there is an energy supply shortage.