Indoxyl sulfate-induced epithelial-to-mesenchymal transition and apoptosis of renal tubular cells as novel mechanisms of progression of renal disease.
Indoxyl sulfate (IS), one of the uremic toxins, is regarded to have a substantial role in the progression of chronic kidney disease (CKD). Epithelial-to-mesenchymal transition (EMT) and apoptosis of renal tubular cells are known to be the critical mechanisms of the development and aggravation of CKD. We investigated the effect of IS on EMT and apoptosis in renal proximal tubular cells, NRK-52E cells. IS significantly inhibited cell proliferation and induced cell migration with a morphological transition from cuboidal epithelial cells to spindle-shaped scattered fibroblast-like cells. IS downregulated the expressions of zonula occluden-1 and E-cadherin, whereas upregulated α-SMA expression at 48 h, which was blocked by a pretreatment of the organic anion transporter, probenecid. IS also induced apoptosis of NRK cells from a concentration of 25 μg/ml with an activation of ERK1/2 and p38 MAP kinase (MAPK). Pretreatment of ERK1/2 or p38 MAPK inhibitors, PD98059 or SB203580, resulted in no significant effect on IS-induced EMT, whereas it ameliorated IS-induced apoptosis of NRK cells. These findings suggested phenotypic transition and apoptosis as potential mechanisms of IS-induced renal damage and the differential role of MAPK activation in IS-induced EMT and apoptosis of renal tubular cells.
Division of Nephrology, Department of Internal Medicine, Chung-Ang University, Seoul, Korea.
Su Hyun
SH
Kim
Min-A
MA
Yu
Eun Sun
ES
Ryu
Yang-Hee
YH
Jang
Duk-Hee
DH
Kang
D000199:Actins / Q000378:metabolism; D000818:Animals; D017209:Apoptosis; D015820:Cadherins / Q000378:metabolism; D002460:Cell Line; D002465:Cell Movement; D049109:Cell Proliferation; D018450:Disease Progression; D004789:Enzyme Activation; D058750:Epithelial-Mesenchymal Transition; D007200:Indican / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D051381:Rats; D051436:Renal Insufficiency, Chronic / Q000378:metabolism*; D015398:Signal Transduction; D062826:Zonula Occludens-1 Protein; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D000199:Actins; D015820:Cadherins; D007200:Indican; D008565:Membrane Proteins; D019950:Mitogen-Activated Protein Kinase 1; D010750:Phosphoproteins; D062826:Zonula Occludens-1 Protein; D048051:p38 Mitogen-Activated Protein Kinases; C569044:Tjp1 protein, rat; C498862:Acta2 protein, rat