Chen Phang-Lang, Chen Chi-Fen, Lin Hugo Y-H, Riley Daniel J, Chen Yumay
Department of Biological Chemistry, University of California, Irvine, CA 92697, USA.
Division of Nephrology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
Int J Mol Sci. 2024 Mar 2;25(5):2936. doi: 10.3390/ijms25052936.
In autosomal dominant polycystic kidney disease (ADPKD) with germline mutations in a or 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 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.
在携带PKD1或PKD2基因种系突变的常染色体显性多囊肾病（ADPKD）中，肾小管会形成无数囊肿，肾功能也会恶化。第二次打击体细胞突变和肾小管上皮（RTE）细胞死亡是囊肿起始和疾病进展的关键特征。在此，我们使用已建立的RTE细胞系和带有疾病相关PKD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损伤的易感性增加以及检查点激活延迟。对人肾组织的免疫组化分析证实了在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，也未正确激活下游转导器（CHK1/CHK2）。ADPKD细胞也具有转化能力，因为它们能达到高饱和密度并在软琼脂中形成集落。我们的研究表明，有缺陷的DNA损伤修复途径及其导致的体细胞突变在根本上促成了ADPKD的发病机制。获得性突变可能会赋予克隆性扩增的细胞群体增殖优势或导致细胞凋亡。对ADPKD中异常DNA损伤反应分子细节的进一步了解正在进行中，有望实现靶向治疗。
