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Updated: Jun 7, 2026
Isolation of Primary Patient-specific Aortic Smooth Muscle Cells and Semiquantitative Real-time Contraction Measurements In Vitro
Published on: February 15, 2022
Cardiac origin of smooth muscle cells in the inflow tract
Haruko Nakano1, Estrelania Williams, Masahiko Hoshijima
1Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA.
Insights
Multipotent Isl1(+) heart progenitors generate cardiac and smooth muscle cells. A transient Isl1(+)/SLN(+) cell population in the heart-vessel junction contributes to both cell types, revealing a shared developmental origin.
Area of Science:
- Developmental biology
- Cardiovascular research
- Stem cell biology
Background:
- Multipotent Isl1(+) heart progenitors are crucial for cardiovascular cell development.
- Understanding lineage decisions in cardiogenesis, particularly cardiac-vascular differentiation, is critical for coordinating heart and vessel growth.
Purpose of the Study:
- To investigate the developmental origin of cardiac and smooth muscle cells at the heart-vessel junction.
- To determine the timing and plasticity of lineage decisions made by Isl1(+) progenitors.
Main Methods:
- Utilized a novel atrial-specific SLN-Cre knockin mouse line.
- Tracked the contribution of Isl1(+) and SLN(+) progenitor cells to cardiovascular lineages.
Main Results:
- Identified a bipotent Isl1(+)/SLN(+) transient cell population.
- Demonstrated that this population contributes to both cardiac and smooth muscle cells at the heart-vessel junction in the cardiac inflow tract.
- Showed that these cells retain plasticity until late gestational stages.
Conclusions:
- Cardiac and smooth muscle cells in the cardiac inflow tract share a common developmental origin from Isl1(+)/SLN(+) progenitors.
- This finding sheds light on the coordinated development of the heart and its associated vasculature.
Abstract:
Multipotent Isl1(+) heart progenitors give rise to three major cardiovascular cell types: cardiac, smooth muscle, and endothelial cells, and play a pivotal role in lineage diversification during cardiogenesis. A critical question is pinpointing when this cardiac-vascular lineage decision is made, and how this plasticity serves to coordinate cardiac chamber and vessel growth. The posterior domain of the Isl1-positive second heart field contributes to the SLN-positive atrial myocardium and myocardial sleeves in the cardiac inflow tract, where myocardial and vascular smooth muscle layers form anatomical and functional continuity. Herein, using a new atrial specific SLN-Cre knockin mouse line, we report that bipotent Isl1(+)/SLN(+) transient cell population contributes to cardiac as well as smooth muscle cells at the heart-vessel junction in cardiac inflow tract. The Isl1(+)/SLN(+) cells are capable of giving rise to cardiac and smooth muscle cells until late gestational stages. These data suggest that the cardiac and smooth muscle cells in the cardiac inflow tract share a common developmental origin. This article is part of a special issue entitled, "Cardiovascular Stem Cells Revisited".
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