TY - JOUR
T1 - Enhanced podocalyxin expression alters the structure of podocyte basal surface
AU - Economou, Constantinos G.
AU - Kitsiou, Paraskevi V.
AU - Tzinia, Athina K.
AU - Panagopoulou, Evridiki
AU - Marinos, Evangelos
AU - Kershaw, David B.
AU - Kerjaschki, Dontscho
AU - Tsilibary, Effie C.
PY - 2004/7/1
Y1 - 2004/7/1
N2 - Glomerular basement membrane. (GBM) and podocalyxin are essential for podocyte morphology. We provide evidence of functional interconnections between basement membrane components (collagen IV and laminin), the expression of podocalyxin and the morphology of human glomerular epithelial cells (podocytes). We demonstrated that GBM and laminin, but not collagen IV, up-regulated the expression of podocalyxin. Scanning electron microscopy revealed that laminin induced a modified morphology of podocytes with process formation, which was more extensive in the presence of GBM. Under high magnification, podocytes appeared ruffled. Using transmission electron microscopy we observed that raised areas occurred in the basal cell surface. Furthermore, the presence of anti-podocalyxin antibody increased the extent of adhesion and spreading of podocytes to both collagen IV and laminin, thus podocalyxin apparently inhibits cell-matrix interactions. We also performed adhesion and spreading assays on podocytes grown under increased glucose concentration (25 mM). Under these conditions, the expression of podocalyxin was almost totally suppressed. The cells adhered and spread to basement membrane components but there was no increase in the extent of adhesion and spreading in the presence of anti-podocalyxin antibody, or ruffling of the cell edges. Additionally, in podocytes expressing podocalyxin, the presence of anti-podocalyxin antibody partially reversed the inhibition of adhesion to collagen IV provoked by anti-β1 integrin antibody, thus podocalyxin should compete with β1-related cell adhesion. We suggest that the observed podocalyxin-mediated inhibition of binding to the matrix could be in part responsible for the specialized conformation of the basal surface of podocytes.
AB - Glomerular basement membrane. (GBM) and podocalyxin are essential for podocyte morphology. We provide evidence of functional interconnections between basement membrane components (collagen IV and laminin), the expression of podocalyxin and the morphology of human glomerular epithelial cells (podocytes). We demonstrated that GBM and laminin, but not collagen IV, up-regulated the expression of podocalyxin. Scanning electron microscopy revealed that laminin induced a modified morphology of podocytes with process formation, which was more extensive in the presence of GBM. Under high magnification, podocytes appeared ruffled. Using transmission electron microscopy we observed that raised areas occurred in the basal cell surface. Furthermore, the presence of anti-podocalyxin antibody increased the extent of adhesion and spreading of podocytes to both collagen IV and laminin, thus podocalyxin apparently inhibits cell-matrix interactions. We also performed adhesion and spreading assays on podocytes grown under increased glucose concentration (25 mM). Under these conditions, the expression of podocalyxin was almost totally suppressed. The cells adhered and spread to basement membrane components but there was no increase in the extent of adhesion and spreading in the presence of anti-podocalyxin antibody, or ruffling of the cell edges. Additionally, in podocytes expressing podocalyxin, the presence of anti-podocalyxin antibody partially reversed the inhibition of adhesion to collagen IV provoked by anti-β1 integrin antibody, thus podocalyxin should compete with β1-related cell adhesion. We suggest that the observed podocalyxin-mediated inhibition of binding to the matrix could be in part responsible for the specialized conformation of the basal surface of podocytes.
KW - Collagen IV
KW - Glomerular basement membrane
KW - Human glomerular epithelial cells
KW - Integrins
KW - Laminin
KW - Podocalyxin
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U2 - 10.1242/jcs.01163
DO - 10.1242/jcs.01163
M3 - Review article
C2 - 15226400
AN - SCOPUS:4344662467
VL - 117
SP - 3281
EP - 3294
JO - The Quarterly journal of microscopical science
JF - The Quarterly journal of microscopical science
SN - 0021-9533
IS - 15
ER -