The C-terminal peptide of connective tissue growth factor blocks the full molecule binding to tubular epithelial cell.
OBJECTIVE
Interstitial fibrosis is a critical pathologic change in chronic allograft nephropathy. The cytokine connective tissue growth factor (CTGF, also CCN2) plays an important role in epithelial-mesenchymal transformation (EMT) of tubular epithelial cells to renal interstitial fibrosis. The hexadeca-peptide within the C-terminal of CTGF (named P2) contains the unique binding domain of CTGF to its potential receptor, integrin alphavbeta3. This study examined whether P2 bound preferentially to the receptor and served as an inhibitor of CTGF.


METHODS
All studies used an established rat kidney tubular epithelial cell line NRK-52E. Chemically synthesized P2 was purified, and some of it labeled with FITC. The affinity of CTGF or P2 to NRK-52E cells was examined by a solid-phase cell adhesion assay. Competitive binding between P2 and CTGF to NRK-52E cells was examined with flow cytometric analysis.


RESULTS
Both P2 and CTGF bound to the NRK-52E cells, mediating cell adhesion. When the cells were incubated in the mixture of P2 and CTGF, P2 bound to the cells preferentially. Furthermore, when cells were preincubated with excessive CTGF, it became difficult for subsequent P2 binding to occur.


CONCLUSIONS
P2 and CTGF seemed to bind to cell membranes at the same binding domain. P2 competitively blocked CTGF binding, acting as a CTGF inhibitor.
Shi
Y
Y
Key Laboratory of Transplant Engineering and Immunology, Ministry of Health, West China Hospital, SiChuan University, Guoxuexiang 37, Chengdu 610041, P.R. China.
Wang
W
W
Tu
Z
Z
Zhang
L
L
Qiu
J
J
Li
Q
Q
Ye
F
F
Li
S
S
Bu
H
H
Li
Y
Y
D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D055513:Connective Tissue Growth Factor; D006801:Humans; D017874:Immediate-Early Proteins / Q000737:chemistry / Q000494:pharmacology*; D036341:Intercellular Signaling Peptides and Proteins / Q000737:chemistry / Q000494:pharmacology*; D007684:Kidney Tubules / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D019459:Urothelium / Q000187:drug effects / Q000502:physiology*
C526317:CCN2 protein, human; C526316:CCN2 protein, rat; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D010446:Peptide Fragments; D055513:Connective Tissue Growth Factor