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Published on: September 23, 2014
Heterogeneic nature of adult cardiac side population cells
Kenichi Yamahara1, Satsuki Fukushima, Steven R Coppen
1Harefield Heart Science Centre, Imperial College London, Middlesex, UK.
Insights
Cardiac side population (cSP) cells in adult mouse hearts are diverse. These cells include vascular, smooth muscle, and mesenchymal stem/progenitor cells, some with cardiomyogenic potential.
Area of Science:
- Cardiovascular Biology
- Stem Cell Biology
- Tissue Engineering
Background:
- Side population (SP) cells are found in adult tissues and are thought to be tissue-specific stem or progenitor cells.
- Cardiac side population (cSP) cells, characterized by Hoechst 33342 efflux and ABCG2 expression, are present in adult murine hearts.
Purpose of the Study:
- To investigate the heterogeneity and differentiation potential of cardiac side population (cSP) cells.
- To characterize the cell surface markers and localization of cSP cells within the adult murine heart.
Main Methods:
- Flow cytometry to analyze cell surface markers (VE-cadherin, alpha-smooth muscle actin, desmin) and ABCG2 expression.
- Immunohistochemistry to determine the localization of ABCG2(+) cells.
- Quantitative RT-PCR to assess gene expression (Nkx2.5, cardiac troponin T, mesodermal markers).
- In vitro cell culture to observe differentiation into osteocytes and adipocytes.
Main Results:
- Over half of cSP cells expressed endothelial (VE-cadherin) or smooth muscle markers (alpha-smooth muscle actin, desmin).
- ABCG2(+) cells were primarily located within vascular walls.
- VE-cadherin(-) cSP cells expressed cardiac-specific genes (Nkx2.5, cardiac troponin T) and mesodermal markers in culture.
- VE-cadherin(-) cSP cells differentiated into osteocytes and adipocytes.
Conclusions:
- Cardiac side population (cSP) cells are heterogeneous, comprising vascular endothelial cells, smooth muscle cells, and mesenchymal stem/progenitor cells.
- A subset of cSP cells possesses cardiomyogenic potential.
- These findings contribute to understanding cardiac stem cell populations and their therapeutic applications.
Abstract:
Side population cells have been found in various types of adult tissue including heart and are presumed to be tissue-specific stem/progenitor cells. In the present study, we confirmed the presence of cardiac side population (cSP) cells, which showed both the Hoechst 33342 efflux ability and ABCG2 expression, in adult murine heart. Flow cytometric analysis showed that more than half of cSP cells expressed the endothelial marker VE-cadherin or the smooth muscle markers, alpha-smooth muscle actin and desmin. In addition, immunohistochemical analysis demonstrated that ABCG2(+) cells were mainly localized within vascular walls. Quantitative RT-PCR analysis demonstrated that VE-cadherin(-) cSP cells progressively expressed Nkx2.5 and cardiac troponin T with time in culture. VE-cadherin(-) cSP cells also expressed mesodermal-mesenchymal-associated markers and differentiated into osteocytes and adipocytes. These results highlight the heterogeneic nature of cSP cells, consisting of vascular endothelial cells, smooth muscle cells, and mesenchymal stem/progenitor cells including potential cardiomyogenic cells.
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