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Isolation of CD146+ Resident Lung Mesenchymal Stromal Cells from Rat Lungs
Published on: June 17, 2016
Mesenchymal stem cell marker Stro-1 is a 75 kd endothelial antigen
Hongxiu Ning1, Guiting Lin, Tom F Lue
1Knuppe Molecular Urology Laboratory, Department of Urology, School of Medicine, University of California, San Francisco, CA 94143-0738, USA.
Abstract:
Stro-1 is the best-known mesenchymal stem cell (MSC) marker. However, previous studies have observed its expression in the endothelium. In the present study we performed immunofluorescence (IF) staining for Stro-1, using endothelial marker vWF as reference. In the liver, both proteins were expressed in the endothelium of the central veins and hepatic sinusoids. In the lung, both were expressed in the endothelium of pulmonary blood vessels, but while vWF was absent in the alveolar capillaries, Stro-1 was present. In the kidney, both were expressed in the endothelium of renal arterial branches, but while vWF was strongly expressed in the glomeruli, Stro-1 only scantly. IF staining in cultured endothelial cells also showed extensive overlaps between Stro-1 and vWF. Western blot analysis with Stro-1 antibody detected a single protein band of 75 kd in endothelial cells but not smooth muscle cells, fibroblasts, or B cells. Cancer cell lines PC3, DU145, MCF7, and K562 were also positive. Adipose-derived stem cells (ADSCs) expressed higher levels of Stro-1 when cultured beyond the first passage or when induced to differentiate into endothelial cells. These data, together with previous studies, indicate that Stro-1 is intrinsically an endothelial antigen, and its expression in MSC is probably an induced event.
Insights
Stro-1 is identified as an endothelial antigen, not solely a mesenchymal stem cell (MSC) marker. Its expression in MSCs is likely induced, challenging its traditional role.
Area of Science:
- Immunology
- Cell Biology
- Histology
Background:
- Stro-1 is widely recognized as a marker for mesenchymal stem cells (MSCs).
- Previous research has indicated Stro-1 expression in endothelial cells, prompting further investigation.
Purpose of the Study:
- To clarify the expression pattern of Stro-1 in various tissues and cell types.
- To determine if Stro-1 is an intrinsic endothelial antigen or a marker primarily for MSCs.
Main Methods:
- Immunofluorescence (IF) staining for Stro-1 and von Willebrand Factor (vWF) in liver, lung, and kidney tissues.
- IF staining in cultured endothelial cells.
- Western blot analysis of Stro-1 expression in various cell lines (endothelial cells, smooth muscle cells, fibroblasts, B cells, cancer cell lines, ADSCs).
Main Results:
- Stro-1 and vWF co-expressed in the endothelium of central veins and hepatic sinusoids (liver).
- Stro-1 was present in lung alveolar capillaries where vWF was absent; both expressed in pulmonary blood vessels.
- Stro-1 expression was scant in renal glomeruli compared to strong vWF expression.
- Western blot confirmed a 75 kDa Stro-1 band in endothelial cells and cancer cell lines, but not in other cell types.
- Adipose-derived stem cells (ADSCs) showed increased Stro-1 expression post-culture or upon endothelial differentiation.
Conclusions:
- Stro-1 is intrinsically an endothelial antigen.
- Its expression in mesenchymal stem cells (MSCs) is likely an induced phenomenon, not a defining characteristic.
