Development of an efficient single-cell cloning and expansion strategy for genome edited induced pluripotent stem cells.

BACKGROUND: Disease-specific human induced pluripotent stem cells (hiPSCs) can be generated directly from individuals with known disease characteristics or alternatively be modified using genome editing approaches to introduce disease causing genetic mutations to study the biological response of those mutations. The genome editing procedure in hiPSCs is still inefficient, particularly when it comes to homology directed repair (HDR) of genetic mutations or targeted transgene insertion in the genome and single cell cloning of edited cells. In addition, genome editing processes also involve additional cellular stresses such as poor cell viability and genetic stability of hiPSCs. Therefore, efficient workflows are desired to increase genome editing application to hiPSC disease models and therapeutic applications. METHODS AND RESULTS: To this end, we demonstrate an efficient workflow for feeder-free single cell clone generation and expansion in both CRISPR-mediated knock-out (KO) and knock-in (KI) hiPSC lines. Using StemFlex medium and CloneR supplement in conjunction with Matrigel cell culture matrix, we show that cell viability and expansion during single-cell cloning in edited and unedited cells is significantly enhanced. Keeping all factors into account, we have successfully achieved hiPSC single-cell survival and cloning in both edited and unedited cells with rates as maximum as 70% in less than 2 weeks. CONCLUSION: This simplified and efficient workflow will allow for a new level of sophistication in generating hiPSC-based disease models to promote rapid advancement in basic research and also the development of novel cellular therapeutics.

Establishment and characterization of induced pluripotent stem cell line (IGIBi002-A) from a ß-thalassemia patient with IVS1-5 mutation by non-integrating reprogramming approach.

ß-thalassemia (BT) is a hereditary blood disorder caused by mutations in the ß-globin (HBB) gene leading to severely reduced or no synthesis of the ß-chain of adult hemoglobin. IVS1-5 (G > C) is the most common BT mutation in Indian population and yet no patient-specific cellular models have been generated. Here, we have established an induced pluripotent stem cell (iPSC) line, IGIBi002-A from a thalassemia patient with a homozygous IVS1-5(G > C) mutation. Characterization of IGIBi002-A demonstrated that these iPSCs are free of exogenous reprogramming genes and expressed pluripotent stem cell markers, exhibited a normal karyotype and were potential of three germ layer differentiation.

Generation and characterization of induced pluripotent stem cell line (IGIBi001-A) from a sickle cell anemia patient with homozygous ß-globin mutation.

Sickle cell disease (SCD) is an autosomal recessive disorder caused by a mutation in ß-globin (HBB) gene. We have generated an induced pluripotent stem cell (iPSC) line, IGIBi001-A from an Indian sickle cell patient with a homozygous HBB gene mutation using Sendai virus reprogramming system. Characterization of IGIBi001-A showed that these iPSCs are transgene-free and expressed pluripotent stem cell markers. They had a normal karyotype and were able to differentiate into all three germ layers. This new SCD-iPSC line will contribute to better understanding of the disease biology of sickle cell anemia and for screening of small molecule drugs.