Fibronectin inhibits endocytosis of calcium oxalate crystals by renal tubular cells.
BACKGROUND
Fibronectin (FN; 230 kDa) is a multifunctional alpha2-glycoprotein distributed throughout the extracellular matrix and body fluids. We recently reported that FN has a protective effect against injury of renal tubular cells by exposure to oxalate and calcium oxalate (CaOX) crystals and inhibits the adhesion of CaOX crystals to renal tubular cells. In the study presented here, we investigated whether FN has inhibitory effect on crystal endocytosis by renal tubular cells.


METHODS
The inhibitory effect of FN on endocytosis of CaOX crystals by MDCK cells was examined by using a radioactivity uptake assay. Also, crystal endocytosis by cells was morphologically assessed by means of transmission electron microscopy (TEM).


RESULTS
FN had inhibitory effects on CaOX crystal endocytosis by MDCK cells. The morphological TEM study showed that few crystals were taken into cells when FN was added compared to the number of crystals when FN was not added.


CONCLUSIONS
We found that FN had the inhibitory effects on the interaction between crystals and renal tubular cells, including the adhesion or endocytosis of crystals by cells.
Tsujihata
Masao
M
Department of Urology, Osaka University Graduate School of Medicine, Suita, Japan. tsujihata@uro.med.osaka-u.ac.jp
Yoshimura
Kazuhiro
K
Tsujikawa
Kozo
K
Tei
Norihide
N
Okuyama
Akihiko
A
D000818:Animals; D001826:Body Fluids / Q000378:metabolism; D002129:Calcium Oxalate / Q000378:metabolism*; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D004285:Dogs; D004705:Endocytosis / Q000187:drug effects; D005109:Extracellular Matrix / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism* / Q000494:pharmacology; D007684:Kidney Tubules / Q000293:injuries / Q000378:metabolism* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission
D005353:Fibronectins; D002129:Calcium Oxalate