Hhex and Cer1 mediate the Sox17 pathway for cardiac mesoderm formation in embryonic stem cells

Area of Science:

• Developmental Biology
• Stem Cell Biology
• Molecular Biology

Background:

• Cardiac muscle differentiation is a complex process guided by growth factor signals.
• The transcription factor Sox17 (Sox17) plays a role in inducing Mesp1 during early cardiac development.
• Downstream targets of Sox17 in cardiac differentiation were not fully understood.

Purpose of the Study:

• To identify and functionally validate downstream effectors of Sox17 in mouse embryonic stem cells (mESCs).
• To elucidate the role of Sox17-regulated genes in cardiac myogenesis.
• To understand the sequential signaling pathway governing cardiac differentiation.

Main Methods:

• Genome-wide profiling of Sox17-dependent genes in mESCs.
• RNA interference (RNAi) to suppress gene function.
• Chromatin immunoprecipitation (ChIP) to assess DNA binding.
• Luciferase reporter assays to measure gene transcription.

Main Results:

• Sox17 regulates the expression of Hhex and Cer1, both critical for mesoderm patterning and cardiac fate.
• Hhex and Cer1 are required for cardiac myogenesis, acting downstream of Mesp1/2 induction.
• Sox17 directly induces Cer1 expression, and Cer1 can rescue cardiac differentiation in Hhex-deficient cells.

Conclusions:

• Hhex and Cer1 are indispensable downstream components of the Sox17 pathway for cardiac differentiation in mESCs.
• The Sox17-Hhex-Cer1 axis is essential for cardiopoiesis, acting after Mesp1/2 induction.
• This study clarifies a key molecular pathway regulating early cardiac development.