Statement of Benefit to California:
Year 1During the reporting period, we have made significant progress toward the following research aims: (1) Screened small molecules and identified a robust and specific condition that can convert murine epiblast-stage pluripotent cells (that correspond to the conventional human embryonic stem/hES cells) to murine embryonic stem cell-like cells that exhibit similar cellular behaviors to various signaling pathway modulations and most importantly contribute to chimerism in vivo as mES cells. This validated the concept of and a chemically defined condition for converting later developmental stage (i.e., post-implantation, late epiblast) of pluripotency to earlier developmental stage (i.e., pre-implantation, inner cell mass) of pluripotency. (2). Established a series of reliable assays to examine hES cell conversion, including markers and cell behaviors under various signaling conditions. (3) Validated the concept that human cells could exhibit a different pluripotency state that is similar to mESC by combining the small molecules and the genetic reprogramming approach. Those novel human pluripotent cells generated from somatic cells share similar colony morphology and responses to signaling modulations as mESCs. This establishes a basis for identifying new small molecules and fine-tuning the converting as well as maintenance conditions for ultimately achieving derivation of ICM-stage, mESC-like hES cells.