Elucidation of the mechanism of crystal-cell interaction using fibronectin-overexpressing Madin-Darby canine kidney cells.
BACKGROUND
Attachment of newly formed crystals to renal epithelial cells is considered to be a critical step in stone formation. Previously, we reported that exogenous fibronectin (FN; 220-240 kDa) had an inhibitory effect against renal tubular cell injury in Madin-Darby canine kidney (MDCK) cells. However, the exact mechanism of FN is not fully understood. To examine the role of FN in crystal-cell interaction, we generated stably transfected MDCK cells that overexpress FN.


METHODS
MDCK cells were transfected with rat FN cDNA. First, we assessed cell injury by addition of calcium oxalate monohydrate (COM) crystals. Next, we examined the effect of FN on the adhesion of COM crystals. Finally, we studied the association of COM crystals by scanning electron microscopy.


RESULTS
Cell injury was significantly reduced in the transfected cells relative to control MDCK cells. In the inhibitory assay, crystal adhesion decreased markedly as compared with control MDCK cells. Morphological study showed that few crystals were attached to the surface of the transfected cells.


CONCLUSIONS
We elucidated the relationship between crystal-cell interaction and FN by using FN-overexpressing MDCK cells. We suppose that FN inhibits the adhesion of crystals to cells by coating the renal tubular epithelial cells.
Tsujikawa
Kozo
K
Department of Urology, Osaka University Graduate School of Medicine, Osaka, Japan.
Tsujihata
Masao
M
Tei
Norihide
N
Yoshimura
Kazuhiro
K
Nonomura
Norio
N
Okuyama
Akihiko
A
D000818:Animals; D002129:Calcium Oxalate / Q000494:pharmacology*; D002448:Cell Adhesion / Q000502:physiology; D002450:Cell Communication / Q000502:physiology; D002478:Cells, Cultured; D003460:Crystallization; D004285:Dogs; D004847:Epithelial Cells / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D005353:Fibronectins / Q000096:biosynthesis* / Q000235:genetics; D015870:Gene Expression; D007668:Kidney / Q000166:cytology; D008855:Microscopy, Electron, Scanning; D019999:Pharmaceutical Solutions / Q000494:pharmacology*; D051381:Rats; D014162:Transfection
D005353:Fibronectins; D019999:Pharmaceutical Solutions; D002129:Calcium Oxalate