ZO-1 expression and phosphorylation in diabetic nephropathy.
Cellular mechanisms responsible for the loss of capillary wall permselectivity in diabetic nephropathy are not well characterized. ZO-1 is a junctional protein involved in the assembly and proper function of a number of tight junctions and is also expressed at the junction of podocytes with the slit diaphragm. We investigated the effect of diabetes and high glucose concentration on the expression of ZO-1 in animal models of both type 1 and 2 diabetes and in rat glomerular epithelial cells. In diabetic animals, immunohistochemistry and Western blotting showed decreased expression of ZO-1 in glomeruli. Immunogold electron microscopy revealed redistribution of ZO-1 from the podocyte membrane to the cytoplasm in the diabetic animals. Exposure of rat glomerular epithelial cells to high glucose resulted in a decrease in the intensity of ZO-1 staining and redistribution of ZO-1 from the membrane to the cytoplasm, changes that are attenuated by blockade of the angiotensin II type 1 receptor. ZO-1 protein expression and serine and tyrosine phosphorylation of ZO-1 were also decreased in cells exposed to high glucose. These findings suggest that alterations in the content and localization of ZO-1 may be relevant to the pathogenesis of proteinuria in diabetes.
Rincon-Choles
Hernan
H
South Texas Veterans Health Care System, San Antonio, TX, USA. choles@uthscsa.edu
Vasylyeva
Tetyana L
TL
Pergola
Pablo E
PE
Bhandari
Basant
B
Bhandari
Kusum
K
Zhang
Jian-Hua
JH
Wang
Wen
W
Gorin
Yves
Y
Barnes
Jeffrey L
JL
Abboud
Hanna E
HE
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism; D003928:Diabetic Nephropathies / Q000378:metabolism*; D004195:Disease Models, Animal; D007672:Kidney Cortex / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism*; D010766:Phosphorylation; D050199:Podocytes / Q000378:metabolism; D021381:Protein Transport; D011507:Proteinuria; D051381:Rats; D017207:Rats, Sprague-Dawley; D062826:Zonula Occludens-1 Protein
D001786:Blood Glucose; D008565:Membrane Proteins; D010750:Phosphoproteins; C569043:Tjp1 protein, mouse; C569044:Tjp1 protein, rat; D062826:Zonula Occludens-1 Protein