JMJD5 regulates cell cycle and pluripotency in human embryonic stem cells

Area of Science:

• Cell Biology
• Developmental Biology
• Stem Cell Research

Background:

• A shortened G1 phase in the cell cycle is characteristic of pluripotent stem cells, including human embryonic stem cells (hESCs).
• Understanding the molecular mechanisms regulating this shortened G1 phase is critical for maintaining pluripotency and controlling differentiation.

Purpose of the Study:

• To molecularly define the mechanisms underlying the shortened G1 phase in hESCs.
• To identify key regulators essential for maintaining pluripotency and preventing premature differentiation.

Main Methods:

• Comparative transcriptomic analysis between hESCs and derived endoderm cells.
• Depletion of candidate genes (e.g., JMJD5) in hESCs using genetic manipulation.
• Cell cycle analysis (G1 phase duration) and assessment of pluripotency markers.
• Investigation of downstream targets, including CDKN1A (p21).

Main Results:

• JMJD5 was identified as a critical protein maintaining the short G1 phase in hESCs.
• Depletion of JMJD5 in hESCs led to G1 phase accumulation, loss of pluripotency, and differentiation into ectoderm and trophectoderm.
• The JMJD5 phenotype was linked to the upregulation of CDKN1A (p21).
• Simultaneous depletion of JMJD5 and CDKN1A (p21) restored the rapid G1 phase and rescued pluripotency.

Conclusions:

• The JMJD5/CDKN1A (p21) axis is essential for maintaining the short G1 phase in hESCs.
• This short G1 phase is critical for preserving the pluripotent state of hESCs.
• JMJD5 acts as a key regulator preventing differentiation by controlling cell cycle progression in pluripotent stem cells.