PDF(Pubmed)
Abstract：
In autosomal dominant polycystic kidney disease (ADPKD) with germline mutations in a PKD1 or PKD2 gene, innumerable cysts develop from tubules, and renal function deteriorates. Second-hit somatic mutations and renal tubular epithelial (RTE) cell death are crucial features of cyst initiation and disease progression. Here, we use established RTE lines and primary ADPKD cells with disease-associated PKD1 mutations to investigate genomic instability and DNA damage responses. We found that ADPKD cells suffer severe chromosome breakage, aneuploidy, heightened susceptibility to DNA damage, and delayed checkpoint activation. Immunohistochemical analyses of human kidneys corroborated observations in cultured cells. DNA damage sensors (ATM/ATR) were activated but did not localize at nuclear sites of damaged DNA and did not properly activate downstream transducers (CHK1/CHK2). ADPKD cells also had the ability to transform, as they achieved high saturation density and formed colonies in soft agar. Our studies indicate that defective DNA damage repair pathways and the somatic mutagenesis they cause contribute fundamentally to the pathogenesis of ADPKD. Acquired mutations may alternatively confer proliferative advantages to the clonally expanded cell populations or lead to apoptosis. Further understanding of the molecular details of aberrant DNA damage responses in ADPKD is ongoing and holds promise for targeted therapies.
摘要：
在PKD1或PKD2基因中具有种系突变的常染色体显性多囊肾病（ADPKD）中，无数的囊肿是从小管发育而来的,肾功能恶化。二次体细胞突变和肾小管上皮（RTE）细胞死亡是囊肿发生和疾病进展的重要特征。这里,我们使用已建立的RTE细胞系和具有疾病相关PKD1突变的原代ADPKD细胞来研究基因组不稳定性和DNA损伤反应.我们发现ADPKD细胞遭受严重的染色体断裂,非整倍体,对DNA损伤的敏感性提高,和延迟的检查点激活。人肾脏的免疫组织化学分析证实了培养细胞中的观察结果。DNA损伤传感器（ATM/ATR）被激活，但未定位在受损DNA的核位点，也未正确激活下游换能器（CHK1/CHK2）。ADPKD细胞也有转化的能力，当它们达到高饱和密度并在软琼脂中形成菌落时。我们的研究表明，缺陷的DNA损伤修复途径及其引起的体细胞突变从根本上导致了ADPKD的发病机理。获得的突变可以可选地赋予克隆扩增的细胞群体增殖优势或导致细胞凋亡。对ADPKD中异常DNA损伤反应的分子细节的进一步了解正在进行中，并有望用于靶向治疗。
