Transcriptional landscape changes during human embryonic stem cell derivation.

Area of Science:

• * Developmental Biology
• * Stem Cell Biology
• * Genomics

Background:

• * Human embryonic stem cells (hESCs) are derived from the inner cell mass (ICM) of blastocysts.
• * The post-ICM intermediate (PICMI) stage represents a transitional phase during hESC derivation.
• * Understanding transcriptional changes during this transition is crucial for defining pluripotency states and differentiation potential.

Purpose of the Study:

• * To investigate the transcriptional landscape changes during hESC derivation from ICM to PICMI to hESC.
• * To elucidate the signaling mechanisms governing the ICM to PICMI to hESC transition.
• * To define the role of the PICMI in establishing pluripotent states and differentiation potential.

Main Methods:

• * Comparative RNA sequencing (RNA-seq) was performed on ICMs, PICMIs, and hESCs.
• * Samples were collected in biological and technical triplicates.
• * Statistical analysis was conducted using edgeR with a false discovery rate (FDR) < 0.05.

Main Results:

• * Significant differences in gene expression were observed between ICM, PICMI, and hESC stages.
• * The PICMI showed upregulation of primordial germ cell (PGC) markers and dependence on leukemia inhibitory factor (LIF) signaling.
• * Principle component analysis indicated distinct clustering of ICM, while PICMI and hESCs were in close proximity.
• * Upregulation of the PI3K/AKT/mTOR pathway and predisposition towards the germ cell lineage were observed in the PICMI.

Conclusions:

• * The PICMI represents a distinct intermediate pluripotency stage during hESC derivation.
• * The PICMI exhibits characteristics that may predispose it towards germ cell differentiation.
• * Understanding the PICMI stage can inform strategies for enhancing naïve hESC derivation and germ cell differentiation efficiency.