DiGeorge Syndrome Critical Region 8 (DGCR8) Protein-mediated microRNA Biogenesis Is Essential for Vascular Smooth Muscle Cell Development in Mice
DiGeorge Syndrome Critical Region 8 (DGCR8) Protein-mediated microRNA Biogenesis Is Essential for Vascular Smooth Muscle Cell Development in Mice
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DOI：
10.1074/jbc.m112.351791
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发表时间：
2012-06-01
影响因子：
4.8
通讯作者：
Yue, Junming
中科院分区：
文献类型：
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作者：
Chen, Zixuan;Wu, Jianmin;Yue, Junming
DiGeorge Critical Region 8（DGCR 8）是一种双链RNA结合蛋白，与Drosha相互作用，促进microRNA（miRNA）成熟。然而，DGCR 8在血管平滑肌细胞（VSMC）中的作用还不清楚。为了研究DGCR 8是否有助于VSMC中的miRNA成熟，我们通过将VSMC特异性Cre小鼠（SM 22-Cre）与DGCR 8（loxp/loxp）小鼠杂交来产生DGCR 8条件性敲除（cKO）小鼠。我们发现，VSMC中DGCR 8的缺失导致了广泛的肝出血和胚胎12.5至E13.5天之间的胚胎死亡。DGCR 8 cKO胚胎显示血管扩张和血管结构紊乱。E12.5后DGCR 8科斯的卵黄囊中不存在血管。在体外和体内，破坏VSMC中的DGCR 8降低VSMC增殖并促进凋亡。在DGCR 8 cKO胚胎和敲除VSMC中，分化标记基因，包括α SMA，SM 22和CNN 1，显著下调，ERK 1/2丝裂原活化蛋白激酶和磷脂酰肌醇3-激酶/AKT的存活途径减弱。VSMC中DGCR 8的敲除导致miR-17/92和miR-143/145簇的下调。我们进一步证明了miR-17/92簇促进VSMC增殖并增强VSMC标记基因表达，这可能有助于DGCR 8 cKO突变体的缺陷。我们的研究结果表明，DGCR 8基因是通过调节VSMC增殖，凋亡和分化的血管发育所必需的。
DiGeorge Critical Region 8 (DGCR8) is a double-stranded RNA-binding protein that interacts with Drosha and facilitates microRNA (miRNA) maturation. However, the role of DGCR8 in vascular smooth muscle cells (VSMCs) is not well understood. To investigate whether DGCR8 contributes to miRNA maturation in VSMCs, we generated DGCR8 conditional knockout (cKO) mice by crossing VSMC-specific Cre mice (SM22-Cre) with DGCR8(loxp/loxp) mice. We found that loss of DGCR8 in VSMCs resulted in extensive liver hemorrhage and embryonic mortality between embryonic days (E) 12.5 and E13.5. DGCR8 cKO embryos displayed dilated blood vessels and disarrayed vascular architecture. Blood vessels were absent in the yolk sac of DGCR8 KOs after E12.5. Disruption of DGCR8 in VSMCs reduced VSMC proliferation and promoted apoptosis in vitro and in vivo. In DGCR8 cKO embryos and knockout VSMCs, differentiation marker genes, including alpha SMA, SM22, and CNN1, were significantly down-regulated, and the survival pathways of ERK1/2 mitogen-activated protein kinase and the phosphatidylinositol 3-kinase/AKT were attenuated. Knock-out of DGCR8 in VSMCs has led to down-regulation of the miR-17/92 and miR-143/145 clusters. We further demonstrated that the miR-17/92 cluster promotes VSMC proliferation and enhances VSMC marker gene expression, which may contribute to the defects of DGCR8 cKO mutants. Our results indicate that the DGCR8 gene is required for vascular development through the regulation of VSMC proliferation, apoptosis, and differentiation.