scholarly journals Integrin-Linked Kinase Mediates Bone Morphogenetic Protein 7-Dependent Renal Epithelial Cell Morphogenesis

2005 ◽  
Vol 25 (9) ◽  
pp. 3648-3657 ◽  
Author(s):  
Chungyee Leung-Hagesteijn ◽  
Ming Chang Hu ◽  
Ahalya S. Mahendra ◽  
Sunny Hartwig ◽  
Henry J. Klamut ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Branching Morphogenesis ◽  
Mouse Kidney ◽  
Dominant Negative ◽  
Cell Morphogenesis ◽  
Renal Epithelial Cell ◽  
Embryonic Mouse ◽  
Morphogenetic Protein ◽  
Culture Model ◽  
Integrin Linked Kinase

ABSTRACT Bone morphogenetic protein 7 (BMP7) stimulates renal branching morphogenesis via p38 mitogen-activated protein kinase (p38MAPK) and activating transcription factor 2 (ATF-2) (M. C. Hu, D. Wasserman, S. Hartwig, and N. D. Rosenblum, J. Biol. Chem. 279:12051-12059, 2004). Here, we demonstrate a novel role for integrin-linked kinase (ILK) in mediating renal epithelial cell morphogenesis in embryonic kidney explants and identify p38MAPK as a target of ILK signaling in a cell culture model of renal epithelial morphogenesis. The spatial and temporal expression of ILK in embryonic mouse kidney cells suggested a role in branching morphogenesis. Adenovirus-mediated expression of ILK stimulated and expression of a dominant negative ILK mutant inhibited ureteric bud branching in embryonic mouse kidney explants. BMP7 increased ILK kinase activity in inner medullary collecting duct 3 (IMCD-3) cells, and adenovirus-mediated expression of ILK increased IMCD-3 cell morphogenesis in a three-dimensional culture model. In contrast, treatment with a small molecule ILK inhibitor or expression of a dominant negative-acting ILK (ILKE359K) inhibited epithelial cell morphogenesis. Further, expression of ILKE359K abrogated BMP7-dependent stimulation. To investigate the role of ILK in BMP7 signaling, we showed that ILK overexpression increased basal and BMP7-induced levels of phospho-p38MAPK and phospho-ATF-2. Consistent with its inhibitory effects on IMCD-3 cell morphogenesis, expression of ILKE359K blocked BMP7-dependent increases in phospho-p38MAPK and phospho-ATF-2. Inhibition of p38MAPK activity with the specific inhibitor, SB203580, failed to inhibit BMP7-dependent stimulation of ILK activity, suggesting that ILK functions upstream of p38MAPK during BMP7 signaling. We conclude that ILK functions in a BMP7/p38MAPK/ATF-2 signaling pathway and stimulates epithelial cell morphogenesis.

scholarly journals Nectin proteins are expressed at early stages of nephrogenesis and play a role in renal epithelial cell morphogenesis

2009 ◽  
Vol 296 (3) ◽  
pp. F564-F574 ◽  
Author(s):  
Paul R. Brakeman ◽  
Kathleen D. Liu ◽  
Kazuya Shimizu ◽  
Yoshimi Takai ◽  
Keith E. Mostov
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Cell Polarity ◽  
Mdck Cells ◽  
Three Dimensional ◽  
Dominant Negative ◽  
Cell Morphogenesis ◽  
Renal Epithelial Cell ◽  
Normal Epithelial Cell ◽  
Three Dimensional Culture

Development of the nephron requires conversion of the metanephric mesenchyme into tubular epithelial structures with specifically organized intercellular junctions. The nectin proteins are a family of transmembrane proteins that dimerize to form intercellular junctional complexes between epithelial cells. In this study, we demonstrate that nectin junctions appear during the earliest stages of epithelial cell morphogenesis in the murine nephron concurrently with the transition of mesenchymal cells into epithelial cells. We have defined the role of nectin during epithelial cell morphogenesis by studying nectin in a three-dimensional culture of Madin-Darby canine kidney (MDCK) cells. In a three-dimensional culture of MDCK cells grown in purified type 1 collagen, expression of a dominant negative form of nectin causes disruption of the formation of cell polarity and disruption of tight junction (TJ) formation, as measured by zonula occludens-1 (ZO-1) localization. In MDCK cells cultured in Matrigel, exogenous expression of nectin-1 causes disruption of normal epithelial cell cyst formation and decreased apoptosis. These data demonstrate that nectins play an important role in normal epithelial cell morphogenesis and may play a role in mesenchymal-to-epithelial transition during nephrogenesis by providing an antiapoptotic signal and promoting the formation of TJs and cell polarity.

scholarly journals A central role for Galectin 3 during renal epithelial cell morphogenesis after nephrectomy

Cilia ◽  
2012 ◽  
Vol 1 (S1) ◽  
Author(s):  
F Poirier ◽  
A Viau ◽  
J Magescas ◽  
M Burtin ◽  
F Terzi ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Cell Morphogenesis ◽  
Renal Epithelial Cell ◽  
Galectin 3

Overexpression of the integrin-linked kinase mesenchymally transforms mammary epithelial cells

2001 ◽  
Vol 114 (6) ◽  
pp. 1125-1136 ◽  
Author(s):  
A. Somasiri ◽  
A. Howarth ◽  
D. Goswami ◽  
S. Dedhar ◽  
C.D. Roskelley
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Mammary Epithelial Cell ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Cell Morphogenesis ◽  
Wild Type ◽  
Integrin Linked Kinase ◽  
E Cadherin ◽  
Cell Cell

Signals generated by the interaction of (β)1 integrins with laminin in the basement membrane contribute to mammary epithelial cell morphogenesis and differentiation. The integrin-linked kinase (ILK) is one of the signaling moieties that associates with the cytoplasmic domain of (β)1 integrin subunits with some specificity. Forced expression of a dominant negative, kinase-dead form of ILK subtly altered mouse mammary epithelial cell morphogenesis but it did not prevent differentiative milk protein expression. In contrast, forced overexpression of wild-type ILK strongly inhibited both morphogenesis and differentiation. Overexpression of wild-type ILK also caused the cells to lose the cell-cell adhesion molecule E-cadherin, become invasive, reorganize cortical actin into cytoplasmic stress fibers, and switch from an epithelial cytokeratin to a mesenchymal vimentin intermediate filament phenotype. Forced expression of E-cadherin in the latter mesenchymal cells rescued epithelial cytokeratin expression and it partially restored the ability of the cells to differentiate and undergo morphogenesis. These data demonstrate that ILK, which responds to interactions between cells and the extracellular matrix, induces a mesenchymal transformation in mammary epithelial cells, at least in part, by disrupting cell-cell junctions.

scholarly journals Colocalization and Redistribution of Dishevelled and Actin during WNT-Induced Mesenchymal Morphogenesis

2000 ◽  
Vol 149 (7) ◽  
pp. 1433-1442 ◽  
Author(s):  
Monica A. Torres ◽  
W. James Nelson
Keyword(s):  
Gene Expression ◽  
Wnt Signaling ◽  
Signaling Pathway ◽  
Wnt Signaling Pathway ◽  
Cell Spreading ◽  
Mesenchymal Cell ◽  
Mouse Kidney ◽  
Cell Morphogenesis ◽  
Embryonic Mouse ◽  
Stimulation Of

Activation of the Wnt signaling pathway is important for induction of gene expression and cell morphogenesis throughout embryonic development. We examined the subcellular localization of dishevelled, the immediate downstream component from the Wnt receptor, in the embryonic mouse kidney. Using immunofluorescence staining, confocal microscopy, and coimmunoprecipitation experiments, we show that dishevelled associates with actin fibers and focal adhesion plaques in metanephric mesenchymal cells. Stimulation of Wnt signaling leads to profound changes in metanephric mesenchymal cell morphology, including disruption of the actin cytoskeleton, increased cell spreading, and increased karyokinesis. Upon activation of Wnt signaling, dishevelled also accumulates in and around the nucleus. Casein kinase Iε colocalizes with dishevelled along actin fibers and in the perinuclear region, whereas axin and GSK-3 are only present around the nucleus. These data indicate a branched Wnt signaling pathway comprising a canonical signal that targets the nucleus and gene expression, and another signal that targets the cytoskeleton and regulates cell morphogenesis.

Electrophysiological Measurements of a Toad Renal Epithelial Cell Line (A6) as an Assay for Predicting Ocular Eye Irritancy

1992 ◽  
Vol 20 (2) ◽  
pp. 218-221
Author(s):  
Henning F. Bjerregaard
Keyword(s):  
Epithelial Cell ◽  
Cell Line ◽  
South African ◽  
Mdck Cells ◽  
Epithelial Cell Line ◽  
Renal Epithelial Cell ◽  
Electrophysiological Measurements ◽  
Renal Epithelial Cell Line ◽  
Darby Canine Kidney

An established epithelial cell line (A6) from a South African clawed toad (Xenopus laevis) kidney was used as a model for the corneal epithelium of the eye in order to determine ocular irritancy. When grown on Millipore filter inserts, A6 cells form a monolayer epithelium of high electrical resistance and generate a trans-epithelial potential difference. These two easily-measured electrophysiological endpoints showed a dose-related decrease after exposure for 24 hours to seven selected chemicals of different ocular irritancy potential. It was demonstrated that both trans-epithelial resistance and potential ranked closely with in vivo eye irritancy data and correlated well (r = 0.96) with loss of trans-epithelial impermeability of Madin-Darby canine kidney (MDCK) cells, detected by use of a fluorescein leakage assay.

scholarly journals Pak1 regulates branching morphogenesis in 3D MDCK cell culture by a PIX and β1-integrin-dependent mechanism

2010 ◽  
Vol 299 (1) ◽  
pp. C21-C32 ◽  
Author(s):  
Michael P. Hunter ◽  
Mirjam M. Zegers
Keyword(s):  
Cell Culture ◽  
Mdck Cell ◽  
Three Dimensional ◽  
3D Culture ◽  
Branching Morphogenesis ◽  
Dominant Negative ◽  
Β1 Integrin ◽  
Blocking Antibody ◽  
Important Regulator ◽  
P21 Activated Kinase

Branching morphogenesis is a fundamental process in the development of the kidney. This process gives rise to a network of ducts, which form the collecting system. Defective branching can lead to a multitude of kidney disorders including agenesis and reduced nephron number. The formation of branching tubules involves changes in cell shape, cell motility, and reorganization of the cytoskeleton. However, the exact intracellular mechanisms involved are far from understood. We have used the three-dimensional (3D) Madin-Darby canine kidney (MDCK) cell culture system to study how p21-activated kinase 1 (Pak1), which is an important regulator of the cytoskeleton, modulates branching. Our data reveal that Pak1 plays a crucial role in regulating branching morphogenesis. Expression of a dominant-negative Pak1 mutant (DN-Pak1) in MDCK cysts resulted in the spontaneous formation of extensions and branching tubules. Cellular contractility and levels of phosphorylated myosin light chain (pMLC) were increased in DN-Pak1 cells in collagen. Expression of a DN-Pak1 mutant that does not bind to PIX (DN-Pak1-ΔPIX) failed to form extensions in collagen and did not have increased contractility. This shows that the DN-Pak1 mutant requires PIX binding to generate extensions and increased contractility in 3D culture. Furthermore, a β1-integrin function-blocking antibody (AIIB2) inhibited the formation of branches and blocked the increased contractility in DN-Pak1 cysts. Taken together, our work shows that DN-Pak1-induced branching morphogenesis requires PIX binding and β1-integrin signaling.

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