Derivation and characterization of two sibling human embryonic stem cell lines from discarded grade III embryos.

Human embryonic stem (hES) cells are a valuable tool for studying human development in addition to their potential applications in regenerative medicine and drug discovery. The role of genetic background and epigenetic influences in development as well as in response to external influences such as drugs and therapies is well recognized. The great ethnic diversity in the Indian subcontinent translates to interindividual variability in drug response and disease susceptibility. For these reasons, new hES cell lines representing Indian genetic diversity will be valuable in studies of tissue-differentiation, cellular-function and for aspects of characterization of responses to drugs. We have derived two new hES cell lines, BJNhem19 and BJNhem20 from the inner cell mass (ICM) of discarded grade III human embryos that were not suitable for in vitro fertility treatment. Human leukocyte antigen (HLA) isotype analysis shows that they are genetically distinct from existing hES cell lines. Short tandem repeat (STR) analysis shows that the two cell lines are derived from sibling embryos. These cell lines show an undifferentiated phenotype in culture for more than 65 passages, show normal karyotype and express pluripotency markers such as TRA-1-60, TRA-1-81, stage-specific embryonic antigen-4 (SSEA-4), alkaline phosphatase, DNMT3B, GABRB3, GDF3, OCT4, NANOG, SOX2, TERF1, TDGF, LEFTA, THY1, and REX1. While both cell lines can differentiate into derivatives of all three germ layers in vitro, only BJNhem20 can form teratomas when transplanted into mice. We observe an increased frequency of cardiomyocyte differentiation from BJNhem20 embryoid bodies in feeder-free cultures upon induction with DMSO. Cardiomyocytes purified from such cultures survive and show rhythmic contractions for several weeks in culture. These hES cell lines have been accepted for deposit in the U.K. Stem Cell Bank and will be a useful resource for the international stem cell community.