Loss or oncogenic mutation of DROSHA impairs kidney development and function, but is not sufficient for Wilms tumor formation
Loss or oncogenic mutation of DROSHA impairs kidney development and function, but is not sufficient for Wilms tumor formation
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DOI：
10.1002/ijc.31952
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发表时间：
2019-03-15
影响因子：
6.4
通讯作者：
Gessler, Manfred
中科院分区：
文献类型：
--
作者：
Kruber, Philip;Angay, Oguzhan;Gessler, Manfred
肾母细胞瘤是儿童最常见的肾癌。微处理器基因DROSHA和Dgcr8的突变已被确定为可能的致癌驱动因素，表明异常的miRNA处理在WT的形成中起着关键作用。为了研究DROSHA突变在肾脏发育中的体内作用及其致癌潜力，我们分析了靶向缺失DROSHA或可诱导表达携带肿瘤特异性E1147K突变的人DROSHA的小鼠品系，该突变以显性负向方式发挥作用。这两种类型的突变都会导致miRNA模式的显著变化。SIX2-cre介导的肾单位祖细胞DROSHA缺失可导致围产儿死亡，并导致前体细胞的凋亡丢失和肾脏发育的提前终止。通过Wt1-cre(ERT2)的嵌合体缺失导致了较温和的表型，存活的后代在2-4周后出现蛋白尿，但没有肿瘤形成的证据。另一方面，通过SIX2-cre激活DROSHA-E1147K转基因导致了更严重的表型，表现为祖细胞凋亡、蛋白尿和肾小球硬化。严重生长迟缓的小鼠在出生后的头两个月内死亡，证实了DROSHA-E1147K在体内预测的显性-负面效应。虽然我们的数据强调了可行的自我更新祖细胞池对肾脏发育的重要性，但没有证据表明DROSHA功能受损会导致肿瘤形成。这表明，恶性转化需要有丝分裂或抗凋亡途径的额外改变，或者过早失去敏感的靶细胞群和早期致死性阻止WT的形成。
Wilms tumor (WT) is the most common kidney cancer in childhood. Mutations in the microprocessor genes DROSHA and DGCR8 have been identified as putative oncogenic drivers, indicating a critical role of aberrant miRNA processing in WT formation. To characterize the in vivo role of DROSHA mutations during kidney development and their oncogenic potential, we analyzed mouse lines with either a targeted deletion of Drosha or an inducible expression of human DROSHA carrying a tumor-specific E1147K mutation that acts in a dominant negative manner. Both types of mutation induce striking changes in miRNA patterns. Six2-cre mediated deletion of Drosha in nephron progenitors led to perinatal lethality with apoptotic loss of progenitor cells and early termination of nephrogenesis. Mosaic deletions via Wt1-cre(ERT2) resulted in a milder phenotype with viable offspring that developed proteinuria after 2-4 weeks, but no evidence of tumor formation. Activation of the DROSHA-E1147K transgene via Six2-cre, on the other hand, induced a more severe phenotype with apoptosis of progenitor cells, proteinuria and glomerular sclerosis. The severely growth retarded mice died within the first 2 months of life, confirming the predicted dominant-negative effect of DROSHA-E1147K in vivo. While our data underscores the importance of a viable self-renewing progenitor pool for kidney development, there was no evidence of tumor formation through impaired DROSHA function. This suggests that either additional alterations in mitogenic or antiapoptotic pathways are needed for malignant transformation, or premature loss of a susceptible target cell population and early lethality prevent WT formation.