Inhibition of heparin-binding epidermal growth factor-like growth factor increases albuminuria in puromycin aminonucleoside nephrosis.
BACKGROUND
Our previous work in the acute puromycin aminonucleoside nephrosis (PAN) model has demonstrated up-regulation of heparin-binding epidermal growth factor-like growth factor (HB-EGF) mRNA and protein within glomerular epithelial cells (GECs) prior to the onset of proteinuria.


METHODS
To determine whether increased HB-EGF expression in the acute PAN model contributes to the pathogenesis of proteinuria, a monoclonal antibody (DE10) was produced against recombinant human HB-EGF.


RESULTS
The specificity of DE10 for human HB-EGF was confirmed by enzyme-linked immunosorbent assay, immunohistochemical staining, and flow cytometry of transfected cells expressing human and rat HB-EGF, and inhibition of cell proliferation. DE10 also reacted with cells transfected with rat HB-EGF cDNA. Administration of 0.5 mg affinity-purified DE10 to normal rats did not cause significant albuminuria compared with controls. Five days after the induction of the acute PAN model, albuminuria was significantly greater in animals treated with 0.5 mg DE10 than a control mAb (162.6 +/- 32.4 vs. 64.8 +/- 10.2 mg/day, respectively, P < 0.01). Rats treated with DE10 had an earlier onset of severe albuminuria, but no increase in maximal albuminuria at later time points. Electron microscopy showed marked podocyte effacement in both DE10-treated and control animals, but no obvious difference between groups. However, adhesion of the human GEC line 56/10 A1 to laminin and fibronectin, but not to collagens I or IV, was reduced by DE10.


CONCLUSIONS
This study suggests that HB-EGF contributes to the integrity of the glomerular filtration barrier, particularly when the podocyte has been injured. Following podocyte injury, adhesion to laminin in the glomerular basement membrane by HB-EGF may be important in reducing albuminuria.
Khong
T F
TF
Immunology Research Center and the Department of Anatomical Pathology, St. Vincent's Hospital, Fitzroy, Victoria, Australia.
Fraser
S
S
Katerelos
M
M
Paizis
K
K
Hill
P A
PA
Power
D A
DA
D016475:3T3 Cells; D000199:Actins / Q000378:metabolism; D000419:Albuminuria / Q000139:chemically induced / Q000209:etiology / Q000503:physiopathology*; D000818:Animals; D000903:Antibiotics, Antineoplastic; D000911:Antibodies, Monoclonal / Q000032:analysis / Q000494:pharmacology*; D000918:Antibody Specificity; D016466:CHO Cells; D019556:COS Cells; D002448:Cell Adhesion / Q000276:immunology; D006224:Cricetinae; D004815:Epidermal Growth Factor / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D005919:Glomerular Filtration Rate; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D039201:Integrin alpha3beta1; D016023:Integrins / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins; D007668:Kidney / Q000166:cytology / Q000276:immunology / Q000648:ultrastructure; D051379:Mice; D008807:Mice, Inbred BALB C; D018613:Microscopy, Confocal; D008854:Microscopy, Electron; D009401:Nephrosis / Q000139:chemically induced / Q000209:etiology / Q000503:physiopathology*; D009500:Neutralization Tests; D011692:Puromycin Aminonucleoside; D051381:Rats; D014162:Transfection
D000199:Actins; D000903:Antibiotics, Antineoplastic; D000911:Antibodies, Monoclonal; C587883:HBEGF protein, human; C587884:Hbegf protein, mouse; C587885:Hbegf protein, rat; D066257:Heparin-binding EGF-like Growth Factor; D039201:Integrin alpha3beta1; D016023:Integrins; D036341:Intercellular Signaling Peptides and Proteins; D011692:Puromycin Aminonucleoside; D004815:Epidermal Growth Factor