Expression dynamics of HAND1/2 in in vitro human cardiomyocyte differentiation

Area of Science:

• Cardiovascular Biology
• Stem Cell Biology
• Gene Regulation

Background:

• Hand1 and Hand2 transcription factors are essential for heart development in mice.
• Their specific roles and expression patterns during human cardiogenesis remain largely uncharacterized.

Purpose of the Study:

• To investigate the expression dynamics of HAND1 and HAND2 during human cardiac differentiation in vitro.
• To assess the function of HAND1 and HAND2 in human cardiomyocytes (CMs) and identify factors regulating CM proliferation.

Main Methods:

• Established triple-reporter human induced pluripotent stem cell lines for simultaneous tracking of HAND1, HAND2, and cardiac markers.
• Utilized RNA sequencing to profile cardiomyocyte subpopulations and identify regulatory gene networks.
• Investigated cell proliferation and identified surface markers using flow cytometry and immunofluorescence.

Main Results:

• HAND1 expression was detected in cardiac progenitor cells by day 5 of differentiation.
• RNA sequencing revealed that HAND1-expressing CMs (mCherry+) exhibited higher proliferative capacity.
• A gene network involving LEF1, HAND1, and HAND2 was identified as crucial for regulating CM proliferation.
• CD105 was identified as a surface marker for highly proliferative CMs.

Conclusions:

• HAND1 and HAND2 play significant roles in human cardiogenesis and cardiomyocyte proliferation.
• The LEF1-HAND1-HAND2 gene network is a key regulator of cardiomyocyte expansion.
• CD105 serves as a valuable marker for identifying and isolating proliferative cardiomyocytes for further study and therapeutic applications.