Cure of ADPKD by Selection for Spontaneous Genetic Repair Events in Pkd1-Mutated iPS Cells

Induced pluripotent stem cells (iPSCs) generated by epigenetic reprogramming of personal somatic cells have limited therapeutic capacity for patients suffering from genetic disorders. Here we demonstrate restoration of a genomic mutation heterozygous for Pkd1 (polycystic kidney disease 1) deletion (Pkd1(+/−) to Pkd1(+/R+)) by spontaneous mitotic recombination. Notably, recombination between homologous chromosomes occurred at a frequency of 1∼2 per 10,000 iPSCs. Southern blot hybridization and genomic PCR analyses demonstrated that the genotype of the mutation-restored iPSCs was indistinguishable from that of the wild-type cells. Importantly, the frequency of cyst generation in kidneys of adult chimeric mice containing Pkd1(+/R+) iPSCs was significantly lower than that of adult chimeric mice with parental Pkd1(+/−) iPSCs, and indistinguishable from that of wild-type mice. This repair step could be directly incorporated into iPSC development programmes prior to cell transplantation, offering an invaluable step forward for patients carrying a wide range of genetic disorders.通过对个体体细胞进行表观重编程获得的诱导多能干细胞（induced pluripotent stem cells，iPSCs），对遗传性疾病患者的治疗潜能较为有限。本研究通过自发有丝分裂重组，成功修复了Pkd1（多囊肾病1，polycystic kidney disease 1）的杂合缺失突变（将Pkd1(+/−)修复为Pkd1(+/R+)）。值得注意的是，同源染色体间的重组频率约为每10000个iPSCs中发生1~2次。Southern印迹杂交与基因组PCR分析结果显示，突变修复后的iPSCs的基因型与野生型细胞几乎无差异。更为重要的是，携带Pkd1(+/R+) iPSCs的成年嵌合小鼠肾脏中囊肿生成频率，显著低于携带亲本Pkd1(+/−) iPSCs的成年嵌合小鼠，且与野生型小鼠的囊肿生成频率无显著差异。该修复步骤可在细胞移植前直接整合至iPSC制备流程中，为携带各类遗传性疾病的患者带来了极具价值的研究突破。