Departamento de Anatomía y Biología Celular and IDIVAL, Universidad de Cantabria, 39011 Santander, Spain.
Cells. 2022 Dec 31;12(1):175. doi: 10.3390/cells12010175.
Considering the importance of programmed cell death in the formation of the skeleton during embryonic development, the aim of the present study was to analyze whether regulated cell degeneration also accompanies the differentiation of embryonic limb skeletal progenitors in high-density tridimensional cultures (micromass cultures). Our results show that the formation of primary cartilage nodules in the micromass culture assay involves a patterned process of cell death and cell senescence, complementary to the pattern of chondrogenesis. As occurs in vivo, the degenerative events were preceded by DNA damage detectable by γH2AX immunolabeling and proceeded via apoptosis and cell senescence. Combined treatments of the cultures with growth factors active during limb skeletogenesis, including FGF, BMP, and WNT revealed that FGF signaling modulates the response of progenitors to signaling pathways implicated in cell death. Transcriptional changes induced by FGF treatments suggested that this function is mediated by the positive regulation of the genetic machinery responsible for apoptosis and cell senescence together with hypomethylation of the gene promoter. We propose that FGF signaling exerts a primordial function in the embryonic limb conferring chondroprogenitors with their biological properties.
考虑到程序性细胞死亡在胚胎发育过程中骨骼形成中的重要性，本研究的目的是分析在高密度三维培养（微团培养）中，调节细胞退化是否也伴随着胚胎肢骨祖细胞的分化。我们的结果表明，微团培养分析中初级软骨结节的形成涉及细胞死亡和细胞衰老的模式过程，与软骨发生的模式互补。与体内发生的情况一样，退行性事件发生在可通过 γH2AX 免疫标记检测到的 DNA 损伤之前，并通过细胞凋亡和细胞衰老进行。用在肢骨发生过程中起作用的生长因子（包括 FGF、BMP 和 WNT）联合处理培养物表明，FGF 信号转导调节祖细胞对涉及细胞死亡的信号通路的反应。FGF 处理诱导的转录变化表明，该功能是通过对负责细胞凋亡和细胞衰老的遗传机制的正调控以及基因启动子的低甲基化来介导的。我们提出，FGF 信号在胚胎肢中发挥原始功能，赋予软骨祖细胞其生物学特性。
