TY - JOUR
T1 - Mechanical stress reduces podocyte proliferation in vitro
AU - Petermann, Arndt T.
AU - Hiromura, Keiju
AU - Blonski, Mary
AU - Pippin, Jeffrey
AU - Monkawa, Toshi
AU - Durvasula, Raghu
AU - Couser, William G.
AU - Shankland, Stuart J.
N1 - Funding Information:
This study was supported by Public Health Service grants (DK34198, DK52121, DK51096, DK56799) and a George M. O'Brien Kidney Research Center Grant (DK47659). A.T. Petermann was supported by a grant from the Deutsche Forschungsgemeinschaft.
PY - 2002
Y1 - 2002
N2 - Background. Mechanical stretch, a consequence of capillary glomerular hypertension, is thought to be the common final pathway for glomerulosclerosis in systemic hypertension, diabetes, reduced nephron number and focal segmental glomerulosclerosis. However, the effects of stretch on podocyte growth and the mechanisms that underlie this have not been elucidated. Methods. Mouse podocyte growth (3H-thymidine, MTT-assay, FACS) was measured following the application of mechanical stretch created by vacuum. The expression of specific cell cycle regulatory proteins was examined by RNAse protection assay and Western blot analysis. Control cells were grown under similar conditions, but were not exposed to stretch. Results. Mechanical stretch decreased DNA-synthesis (3H-thymidine incorporation) and cell number (MTT-assay) in podocytes at 24, 48 and 72 hours (P lt; 0.001 vs. control non-stretched cells), which was not due to apoptosis (Hoechst staining) nor cell detachment. Stretch decreased the mRNA and protein levels of cyclins D1, A and B1 within 24 hours. Stretching cells decreased the activity of Cdk2 (measured by histone H1 kinase assay) at 48 and 72 hours and Cdc2 at 72 hours. In contrast, stretch increased the protein levels of the cyclin dependent kinase inhibitors (CKI) p21cip/Kip/waf (p21) and p27Kip1 (p27) within the first 24 hours, and increased the mRNA levels of p57Kip2 (p57) at 72 hours. To examine the role of p21 in inhibiting proliferation induced by stretch, we studied p21 -/- podocytes in culture. Stretch did not reduce proliferation in p21-/- podocytes (P > 0.05 vs. non-stretched podocytes; P < 0.001 vs. stretched p21 +/+ podocytes). Conclusions. In contrast to mesangial cells, mechanical stretch decreases the growth of podocytes. This effect is mediated through the regulation of specific cell cycle regulatory proteins. These events may explain the apparent lack of podocyte proliferation in diseases correlated with capillary glomerular hypertension.
AB - Background. Mechanical stretch, a consequence of capillary glomerular hypertension, is thought to be the common final pathway for glomerulosclerosis in systemic hypertension, diabetes, reduced nephron number and focal segmental glomerulosclerosis. However, the effects of stretch on podocyte growth and the mechanisms that underlie this have not been elucidated. Methods. Mouse podocyte growth (3H-thymidine, MTT-assay, FACS) was measured following the application of mechanical stretch created by vacuum. The expression of specific cell cycle regulatory proteins was examined by RNAse protection assay and Western blot analysis. Control cells were grown under similar conditions, but were not exposed to stretch. Results. Mechanical stretch decreased DNA-synthesis (3H-thymidine incorporation) and cell number (MTT-assay) in podocytes at 24, 48 and 72 hours (P lt; 0.001 vs. control non-stretched cells), which was not due to apoptosis (Hoechst staining) nor cell detachment. Stretch decreased the mRNA and protein levels of cyclins D1, A and B1 within 24 hours. Stretching cells decreased the activity of Cdk2 (measured by histone H1 kinase assay) at 48 and 72 hours and Cdc2 at 72 hours. In contrast, stretch increased the protein levels of the cyclin dependent kinase inhibitors (CKI) p21cip/Kip/waf (p21) and p27Kip1 (p27) within the first 24 hours, and increased the mRNA levels of p57Kip2 (p57) at 72 hours. To examine the role of p21 in inhibiting proliferation induced by stretch, we studied p21 -/- podocytes in culture. Stretch did not reduce proliferation in p21-/- podocytes (P > 0.05 vs. non-stretched podocytes; P < 0.001 vs. stretched p21 +/+ podocytes). Conclusions. In contrast to mesangial cells, mechanical stretch decreases the growth of podocytes. This effect is mediated through the regulation of specific cell cycle regulatory proteins. These events may explain the apparent lack of podocyte proliferation in diseases correlated with capillary glomerular hypertension.
KW - Capillary glomerular hypertension
KW - Cell cycle
KW - Cyclin dependent kinase
KW - Kidney
KW - Stretch
KW - Visceral glomerular epithelial cell podocyre
KW - p21
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U2 - 10.1046/j.1523-1755.2002.00102.x
DO - 10.1046/j.1523-1755.2002.00102.x
M3 - Article
C2 - 11786083
AN - SCOPUS:0036149007
SN - 0085-2538
VL - 61
SP - 40
EP - 50
JO - Kidney International
JF - Kidney International
IS - 1
ER -
