Leukemia inhibitory factor induces endothelial differentiation in cardiac stem cells

Area of Science:

• Cardiovascular Biology
• Stem Cell Biology
• Molecular Signaling

Background:

• Interleukin 6 (IL-6)-related cytokines are vital for cardiac homeostasis, but their role in cardiac stem cells remains unclear.
• Leukemia inhibitory factor (LIF) is a key cytokine in the IL-6 family.
• Cardiac stem cells (Sca-1+) are a potential source for cardiac regeneration.

Purpose of the Study:

• To investigate the role of LIF in cardiac stem cell differentiation.
• To elucidate the signaling pathways involved in LIF-mediated cardiac stem cell differentiation.
• To determine if LIF can induce cardiac stem cells to differentiate into endothelial cells.

Main Methods:

• Cardiac Sca-1+ stem cells were stimulated with LIF.
• Activation of STAT3 and ERK1/2 pathways was assessed.
• Gene expression of endothelial, smooth muscle, and cardiac muscle markers was analyzed.
• Immunocytochemistry and immunofluorescence microscopy were used to identify cell differentiation.
• Dominant-negative STAT3 and MEK1/2 inhibitor (U0126) were employed to block signaling pathways.

Main Results:

• LIF activated STAT3 and ERK1/2 in cardiac Sca-1+ stem cells.
• LIF induced expression of endothelial cell-specific genes (VE-cadherin, Flk-1, CD31) but not muscle markers.
• Approximately 25% of cells showed CD31 and von Willebrand factor expression, indicating endothelial differentiation.
• IL-6 did not induce endothelial differentiation.
• Inhibition of STAT3 or ERK1/2 abrogated LIF-induced endothelial differentiation.

Conclusions:

• LIF promotes the differentiation of cardiac stem cells into endothelial cells via STAT3 and ERK1/2 activation.
• LIF plays a significant role in regulating cardiac stem cell commitment to the endothelial lineage.
• This process contributes to neovascularization in cardiac tissue remodeling and regeneration.