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6th ESACP Congress, Heidelberg, April 7-11, 1999 |
A061
Cytoskeleton is an essential network of filamentous proteins that contributes
to practically all cellular functions, cell-surface events, interactions with
extracellular matrices, and other processes undergoing during glomerulogenesis.
Complex ultrastructural and immunohistochemical investigation of dynamic
changes of the cytoskeleton along conversion of undifferentiated mesenchymal
cellular aggregates to an epithelial phenotype and further proceeding through
the well-known stages of the human kidney development is under the scope of
this study. Actin appears to be the most abundant element of the cytoskeleton
in the glomerular mesangial cells. A gradual decrease of cytoplasmic actins
along with an increase of muscle-specific actin, in fact, alpha-smooth muscle
actin, is going on during maturation of this glomerular cell that assumed to
be a pericyte for invading blood vessels lined by endothelium. These
phenotypic changes of the actin cytoskeleton in the mesangial cells are
transient, and disappear when the differentiation of glomerulus is complete
in the adult human kidney. In the podocyte the cytoskeleton is presented by
microfilaments and intermediate filaments as well as microtubules. Fused foot
processes reveal an abundant actin network interspersed with local densities
that disappear along the differentiation. The actin cytoskeleton and proteins
associated with it appear to be essential in maturation of the podocyte foot
processes. In conclusion, the peculiarities of the cytoskeleton dynamics
appear to be significant in cells' differentiation and cellular events
occurring during the kidney development.
DISTRIBUTION AND CHANGES OF CYTOSKELETON DURING DIFFERENTATION OF
GLOMERULAR CELLS OF THE DEVELOPING HUMAN KIDNEY
Groma V
Medical Academy of Latvia, Riga, Latvia