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The glomerular mesangium: studies of its developmental origin and markers in vivo and in vitro
H Holthöfer1, K Sainio, A Miettinen
1Department of Bacteriology and Immunology, University of Helsinki, Finland.
Abstract:
Cultured mesangial cells are widely used to explore their role in kidney glomerular functions, but methods to reliably identify these cells in vivo and in vitro are lacking. Furthermore, the proposed relationship of mesangial cells to e.g. fibroblasts and smooth muscle cells has not been systematically studied. Here we wanted to search for markers of practical use also in identifying cultured mesangial cells, and to apply these markers in a study of the origin of glomerular mesangium. No epitopes specific for only mesangial cells could be identified, and no evidence of their true relationship with neural or lymphocytic lineages could be found. Findings with the variety of markers used suggest that mesangial cells may be indistinguishable from smooth muscle cells and fibroblasts. A panel of antibodies, including those against Thy1.1, smooth muscle actin, desmin, cellular fibronectin and beta 1 integrin alpha 1 and alpha 5 chains, and Wistaria floribunda (WFA) and Ricinus communis (RCA I) lectins, were found useful for mesangial cell detection in vivo and in vitro. The origin of glomerular mesangial cells could not be conclusively determined, although the results indirectly suggest that mesangial cells together with endothelial cells migrate to the glomerulus from the outside.
Insights
Identifying kidney mesangial cells is challenging. Researchers found that mesangial cells may be similar to smooth muscle cells and fibroblasts, using several markers for detection in vivo and in vitro.
Area of Science:
- Nephrology
- Cell Biology
- Immunohistochemistry
Background:
- Cultured mesangial cells are vital for studying kidney glomerular function.
- Reliable methods for identifying mesangial cells in vivo and in vitro are currently lacking.
- The relationship between mesangial cells and other cell types like fibroblasts and smooth muscle cells requires systematic investigation.
Purpose of the Study:
- To identify practical markers for detecting mesangial cells, both in vivo and in vitro.
- To investigate the origin of the glomerular mesangium using identified markers.
- To clarify the cellular relationships of mesangial cells.
Main Methods:
- Utilized a panel of antibodies against Thy1.1, smooth muscle actin, desmin, cellular fibronectin, and beta 1 integrin alpha 1 and alpha 5 chains.
- Employed Wistaria floribunda (WFA) and Ricinus communis (RCA I) lectins for cell detection.
- Applied these markers to study mesangial cell identification and origin in vivo and in vitro.
Main Results:
- No unique epitopes exclusively identifying mesangial cells were found.
- Evidence supporting a relationship with neural or lymphocytic lineages was absent.
- Mesangial cells demonstrated similarities to smooth muscle cells and fibroblasts based on marker expression.
- The panel of antibodies and lectins proved useful for mesangial cell detection.
Conclusions:
- The study did not definitively determine the origin of glomerular mesangial cells.
- Findings suggest mesangial cells might be indistinguishable from smooth muscle cells and fibroblasts.
- Results indirectly indicate a potential migration of mesangial and endothelial cells into the glomerulus from external sources.