Wnt'er in liver: expression of Wnt and frizzled genes in mouse.
The Wnt signaling pathway is essential for a wide array of developmental and physiological processes. Wnts are extracellular ligands that bind to frizzled (Fz) receptors at the membrane, canonically inducing beta-catenin nuclear translocation and activation. Although beta-catenin has been shown to be critical in liver biology, the expression of the 19 Wnt and 10 Fz genes in liver remains undetermined. We report comprehensive analysis of Wnt and Fz expression in whole liver as well as individual cell types: freshly isolated and plated hepatocytes, biliary epithelial cells, normal and activated stellate and Kupffer cells, and sinusoidal endothelial cells (SECs). Oligonucleotides for the 19 Wnt, 10 frizzled receptors genes, and secreted Frizzled-related protein-1 (sFRP or Fzb) were synthesized based on the available sequences. A total of 11 Wnts and 8 Fz genes and Fzb were expressed in normal liver. Although only 6 Wnt and 5 Fz genes were expressed in freshly isolated hepatocytes, 8 Wnt genes, 7 Fz genes, and Fzb were expressed in plated hepatocytes. Although 12 Wnt and 7 Fz genes were expressed in biliary tree, additional Fz9 and Fzb were only expressed in cultured biliary epithelial cells. The same 14 Wnt and 7 Fz genes were expressed in both activated and normal stellate and Kupffer cells; only Fzb was expressed in their activated state. Also, 11 Wnt, seven Fz, and Fzb genes were expressed in SECs.


CONCLUSIONS
These data indicate that most Wnt and frizzled genes are expressed in the liver and might be playing important roles in liver pathobiology via canonical and noncanonical pathways.
Zeng
Gang
G
Department of Pathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15261, USA.
Awan
Farrukh
F
Otruba
Wade
W
Muller
Peggy
P
Apte
Udayan
U
Tan
Xinping
X
Gandhi
Chandrashekhar
C
Demetris
Anthony J
AJ
Monga
Satdarshan P S
SP
D000818:Animals; D042783:Endothelial Cells / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D051157:Frizzled Receptors / Q000235:genetics* / Q000378:metabolism*; D005786:Gene Expression Regulation; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism; D022781:Hepatocytes / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D007728:Kupffer Cells / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D051153:Wnt Proteins / Q000235:genetics* / Q000378:metabolism*; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism; D000099274:Frizzled-Related Proteins
D051157:Frizzled Receptors; D006023:Glycoproteins; D047908:Intracellular Signaling Peptides and Proteins; D051153:Wnt Proteins; D051176:beta Catenin; D000099274:Frizzled-Related Proteins