Down-regulation of trypsinogen expression is associated with growth retardation in alpha1,6-fucosyltransferase-deficient mice: attenuation of proteinase-activated receptor 2 activity.
Alpha1,6-fucosyltransferase (Fut8) plays important roles in physiological and pathological conditions. Fut8-deficient (Fut8-/-) mice exhibit growth retardation, earlier postnatal death, and emphysema-like phenotype. To investigate the underlying molecular mechanism by which growth retardation occurs, we examined the mRNA expression levels of Fut8-/- embryos (18.5 days postcoitum [dpc]) using a cDNA microarray. The DNA microarray and real-time polymerase chain reaction (PCR) analysis showed that a group of genes, including trypsinogens 4, 7, 8, 11, 16, and 20, were down-regulated in Fut8-/- embryos. Consistently, the expression of trypsinogen proteins was found to be lower in Fut8-/- mice in the duodenum, small intestine, and pancreas. Trypsin, an active form of trypsinogen, regulates cell growth through a G-protein-coupled receptor, the proteinase-activated receptor 2 (PAR-2). In a cell culture system, a Fut8 knockdown mouse pancreatic acinar cell carcinoma, TGP49-Fut8-KDs, showed decreased growth rate, similar to that seen in Fut8-/- mice, and the decreased growth rate was rescued by the application of the PAR-2-activating peptide (SLIGRL-NH2). Moreover, epidermal growth factor (EGF)-induced receptor phosphorylation was attenuated in TGP49-Fut8-KDs, which was highly associated with a reduction of trypsinogens mRNA levels. The addition of exogenous EGF recovered c-fos, c-jun, and trypsinogen mRNA expression in TGP49-Fut8-KDs. Again, the EGF-induced up-regulation of c-fos and c-jun mRNA expression was significantly blocked by the protein kinase C (PKC) inhibitor. Our findings clearly demonstrate a relationship between Fut8 and the regulation of EGF receptor (EGFR)-trypsin-PAR-2 pathway in controlling cell growth and that the EGFR-trypsin-PAR-2 pathway is suppressed in TGP49-Fut8-KDs as well as in Fut8-/- mice.
Li
Wenzhe
W
Department of Glycotherapeutics, Osaka University Graduate School of Medicine, Osaka, Japan.
Nakagawa
Takatoshi
T
Koyama
Nobuto
N
Wang
Xiangchun
X
Jin
Jinhua
J
Mizuno-Horikawa
Yoko
Y
Gu
Jianguo
J
Miyoshi
Eiji
E
Kato
Ikunoshin
I
Honke
Koichi
K
Taniguchi
Naoyuki
N
Kondo
Akihiro
A
D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D015536:Down-Regulation; D004622:Embryo, Mammalian / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism; D005317:Fetal Growth Retardation / Q000378:metabolism*; D005647:Fucosyltransferases / Q000235:genetics*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009842:Oligopeptides / Q000494:pharmacology; D010766:Phosphorylation; D044464:Receptor, PAR-2 / Q000819:agonists / Q000378:metabolism*; D014362:Trypsinogen / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D009842:Oligopeptides; D044464:Receptor, PAR-2; C112356:seryl-leucyl-isoleucyl-glycyl--arginyl-leucinamide; D014362:Trypsinogen; D005647:Fucosyltransferases; C020559:Glycoprotein 6-alpha-L-fucosyltransferase; D066246:ErbB Receptors