CRBP-I in the renal tubulointerstitial compartment of healthy rats and rats with renal fibrosis.
BACKGROUND
Cellular retinol-binding protein I (CRBP-I), a member of the intracellular lipid-binding protein (iLBP) superfamily, is a specific marker of quiescent stellate cells in the healthy human liver. In the diseased fibrotic/cirrhotic liver, portal and septal myofibroblasts acquire CRBP-I expression, while activated hepatic stellate cells maintain their CRBP-I expression. Here, we investigate the distribution of CRBP-I in the renal cortex of healthy rats and rats with renal fibrosis.


METHODS
Kidneys of healthy and adriamycin-treated rats were studied by immunohistochemistry, using antibodies against CRBP-I, desmin, vimentin and alpha-smooth muscle actin (alpha-SMA). Double stainings were done with immunofluorescence. Western blotting was performed to semi-quantify the expression levels of vimentin, desmin, alpha-SMA and CRBP-I.


RESULTS
In the normal rat kidney, the convoluted proximal tubular epithelial cells express CRBP-I; no expression is found in the interstitium, nor in the glomeruli. In the adriamycin-induced fibrotic rat kidney, CRBP-I expression diminishes in the convoluted proximal tubular epithelial cells, whereas peritubular myofibroblasts in the interstitium acquire CRBP-I expression.


CONCLUSIONS
In the tubulointerstitial compartment of the adriamycin-induced fibrotic rat kidney, CRBP-I is expressed in a different pattern than in the healthy rat kidney. As the convoluted proximal tubular epithelial cells dedifferentiate during fibrosis, CRBP-I expression decreases. Furthermore, de novo expression of CRBP-I is found in activated myofibroblast-like cells in the interstitium of adriamycin-treated rats. CRBP-I is therefore a useful marker to identify a subpopulation of activated/ myodifferentiated fibroblasts in the rat kidney.
Van Beneden
Katrien
K
Vrije Universiteit Brussel, Menselijke Anatomie, Laarbeeklaan 103, B-1090 Brussels, Belgium. Katrien.Van.Beneden@vub.ac.be
van Grunsven
Leo A
LA
Geers
Caroline
C
Pauwels
Marina
M
Desmoulière
Alexis
A
Verbeelen
Dierik
D
Geerts
Albert
A
Van den Branden
Christiane
C
D000199:Actins / Q000378:metabolism; D000818:Animals; D000903:Antibiotics, Antineoplastic; D002454:Cell Differentiation; D003893:Desmin / Q000378:metabolism; D004195:Disease Models, Animal; D015536:Down-Regulation; D004317:Doxorubicin; D005355:Fibrosis; D007687:Kidney Tubules, Proximal / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D009400:Nephrosclerosis / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D054840:Retinol-Binding Proteins, Cellular / Q000378:metabolism*; D015854:Up-Regulation; D014746:Vimentin / Q000378:metabolism
D000199:Actins; D000903:Antibiotics, Antineoplastic; D003893:Desmin; D004317:Doxorubicin; D054840:Retinol-Binding Proteins, Cellular; D014746:Vimentin; C498862:Acta2 protein, rat