Interaction between PGE2 and EGF receptor through MAPKs in mouse embryonic stem cell proliferation

Area of Science:

• Stem cell biology
• Molecular signaling
• Cell cycle regulation

Background:

• Embryonic stem (ES) cell self-renewal is crucial for development and regenerative medicine.
• Understanding the molecular mechanisms regulating ES cell proliferation is essential.

Purpose of the Study:

• To investigate the role of Prostaglandin E2 (PGE2) in regulating mouse embryonic stem cell proliferation.
• To identify the specific receptors and signaling pathways involved in PGE2-mediated ES cell growth.

Main Methods:

• Assessed [(3)H]-thymidine incorporation to measure DNA synthesis.
• Analyzed cell cycle regulatory protein expression and cell cycle phase distribution.
• Quantified E-type prostaglandin (EP) receptor mRNA expression.
• Utilized EP1 receptor antagonist and specific pathway inhibitors (PKC, Src, EGF receptor, PI3K/Akt, MAPK).

Main Results:

• PGE2 significantly increased thymidine incorporation, cell cycle protein expression, S-phase percentage, and total cell number in a dose- and time-dependent manner.
• PGE2 primarily upregulated EP1 receptor mRNA expression among EP receptor subtypes.
• EP1 receptor antagonist blocked PGE2-induced effects on cell cycle and proliferation.
• PGE2 triggered phosphorylation of PKC, Src, EGF receptor, PI3K/Akt, and MAPK, which were inhibited by specific blockers.

Conclusions:

• PGE2 stimulates mouse ES cell proliferation through the EP1 receptor.
• The signaling cascade involves MAPK activation, dependent on EP1 receptor-coupled PKC and EGF receptor-coupled PI3K/Akt pathways.