Mechanisms of lectin (phytohemagglutinin)-induced growth in small intestinal epithelial cells.
OBJECTIVE
The lectin phytohemagglutinin is a mitogen for intestinal epithelial cells in vivo. The mechanisms of action are unknown and were therefore analyzed in vitro.


METHODS
Human (Intestine-407) and rat (IEC-6; IEC-18) intestinal epithelial cell lines were stimulated with phytohemagglutinin. Proliferation was assayed by (3)H-thymidine incorporation, activation of mitogen-activated protein kinase (MAPK) by Western blotting, and induction of c-fos mRNA expression by semiquantitative polymerase chain reaction. Control experiments were performed with phenyl-N-acetyl-alpha-D-galactosaminide or the tyrosine kinase inhibitor tyrphostin A25.


RESULTS
Phytohemagglutinin (0.1 microg/ml) significantly stimulated proliferation in all three cell lines after 48-72 h. MAPK activation was detected after 15-30 min, and an induction of c-fos mRNA expression after 15- 30 min of stimulation. Mitogenic effects were blocked by preincubation with phenyl-N-acetyl-alpha-D-galactosaminide or tyrphostin A25.


CONCLUSIONS
Phytohemagglutinin stimulated proliferation, MAPK activation and induction of c-fos mRNA expression. The lectin may contribute to intestinal mucosal growth and regeneration thereby preventing gut atrophy.
Otte
J M
JM
1st Department of Internal Medicine, Christian Albrecht University, Schittenhelmstrasse 12, D-24105 Kiel, Germany.
Chen
C
C
Brunke
G
G
Kiehne
K
K
Schmitz
F
F
Fölsch
U R
UR
Herzig
K H
KH
D000818:Animals; D015153:Blotting, Western; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004247:DNA / Q000096:biosynthesis; D016762:Genes, fos / Q000235:genetics; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D007421:Intestine, Small / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D010835:Phytohemagglutinins / Q000302:isolation & purification / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects
D010835:Phytohemagglutinins; D012333:RNA, Messenger; D004247:DNA; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases