Activating PIK3CA mutation promotes osteogenesis of bone marrow mesenchymal stem cells in macrodactyly
Activating PIK3CA mutation promotes osteogenesis of bone marrow mesenchymal stem cells in macrodactyly
复制标题
激活PIK3CA突变促进巨指骨髓间充质干细胞成骨
DOI：
10.1038/s41419-020-2723-6
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发表时间：
2020-07-06
影响因子：
9
通讯作者：
Wang，Bin
中科院分区：
文献类型：
--
作者：
Cui，Hengqing;Han，Gang;Wang，Bin
巨指症是一种以软组织和骨骼过度生长为特征的致残性先天性疾病，会导致手指肥大和关节畸形。巨指畸形骨质疏松症的发生机制目前尚不清楚。本研究利用显微CT对三例巨指畸形患者的骨表现进行了分析。对肿瘤基因进行下一代测序，检测PIK3CA突变。分析PI3K/AKT/mTOR通路的激活和靶基因。比较大指骨来源的骨髓间充质干细胞(MAC-BMSCs)和多指来源的骨髓间充质干细胞(PD-BMSCs)的成骨能力。检测PIK3CA抑制剂对MAC-BMSCs增殖和成骨能力的影响。所有MAC-BMSCs均检测到PIK3CA的激活突变和PI3K/AKT/mTOR通路的激活。与PD-BMSCs相比，Mac-BMSCs具有更强的成骨能力。经shRNA或BYL719基因敲除的PIK3CA可显著降低MAC-BMSCs的成骨分化能力。RNA-Seq和qRT-PCR结果显示，与PD-BMSCs相比，MAC-BMSCs的DLX5基因表达上调。DLX5基因敲除可抑制MAC-BMSCs的成骨能力，提示DLX5是PIK3CA激活介导的成骨作用的下游靶点。本研究发现PIK3CA激活突变通过PI3K/AKT/mTOR信号通路促进MAC-BMSCs的成骨分化，而PIK3CA基因敲除或药物抑制可逆转其成骨分化作用。
Macrodactyly is a disabling congenital disease characterized by overgrowth of soft tissues and bones, which leads to finger enlargement and joint deformity. The mechanism of bone overgrowth in macrodactyly was rarely understood. In our study bone manifestations of three macrodactyly patients were analyzed by micro-CT. PIK3CA mutation was detected by next-generation sequencing (NGS) of a tumor gene-panel. The PI3K/AKT/mTOR pathway activation and target genes were analyzed. The osteogenic potential of macrodactyly-derived bone marrow mesenchymal stem cells (MAC-BMSCs) was compared with polydactyly-derived bone marrow mesenchymal stem cells (PD-BMSCs). PIK3CA inhibitors were tested for proliferation and osteogenesis potential of MAC-BMSCs. Activating PIK3CA mutations and activation of PI3K/AKT/mTOR pathway were detected in all MAC-BMSCs. MAC-BMSCs had enhanced osteogenesis potential compared with PD-BMSCs. PIK3CA knockdown by shRNA or BYL719 treatment significantly reduced osteogenic differentiation capacity of MAC-BMSCs. RNA-Seq and qRT-PCR revealed the upregulation of distal-less homeobox 5 (DLX5) in MAC-BMSCs compared with PD-BMSCs. The osteogenic potential of MAC-BMSCs was inhibited by DLX5 knockdown, indicating that DLX5 is a downstream target of PIK3CA activation-mediated osteogenesis. This study revealed that osteogenic differentiation in MAC-BMSCs is enhanced by PIK3CA activation mutation through PI3K/AKT/mTOR signaling pathway and can be reversed by PIK3CA knockdown or drug inhibition.