Heparin-binding epidermal growth factor and Src family kinases in proliferation of renal epithelial cells.
Our recent studies have shown that proliferation of renal proximal tubular cells (RPTC) in the absence of growth factors requires activation of the epidermal growth factor (EGF) receptor. We sought to identify the endogenous EGF receptor ligand and investigate the mechanism(s) by which RPTC proliferate in different models. RPTC expressed both pro- and cleaved forms of heparin-binding epidermal growth factor (HB-EGF) and several metalloproteinases (MMP-2, -3, -9, and ADAM10, ADAM17) that have been reported to cleave HB-EGF. Treatment of RPTC with CRM 197, an inhibitor of HB-EGF binding to the EGF receptor, or downregulation of HB-EGF with small interfering RNA inhibited RPTC proliferation following plating. Furthermore, GM6001 (pan-MMP inhibitor), tumor-necrosis factor protease inhibitor-1 (TAPI-1; MMP and ADAM17 inhibitor), and GW280264X (ADAM10 and -17 inhibitor), but not GI254023X (ADAM10 inhibitor), attenuated the proliferation after plating. Although EGF receptor activation is required for RPTC proliferation after oxidant injury, CRM197, GM6001, and TAPI-1 did not block this response. In contrast, inhibition of Src with PP1 blocked EGF receptor activation and RPTC proliferation after oxidant injury. In addition, PP1 treatment attenuated HB-EGF-enhanced RPTC proliferation. We suggest that RPTC proliferation after plating is mediated by HB-EGF produced through an autocrine/paracrine mechanism and RPTC proliferation following oxidant injury is mediated by Src without involvement of HB-EGF.
Zhuang
Shougang
S
Department of Medicine, Brown University School of Medicine, Rhode Island Hospital-Middle House 301, 593 Eddy St., Providence, RI 02903, USA. szhuang@lifespan.org
Kinsey
Gilbert R
GR
Rasbach
Kyle
K
Schnellmann
Rick G
RG
D051722:ADAM Proteins / Q000378:metabolism; D000818:Animals; D019898:Autocrine Communication / Q000502:physiology; D001426:Bacterial Proteins / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D004151:Dipeptides / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism* / Q000502:physiology; D066246:ErbB Receptors / Q000378:metabolism; D005260:Female; D066257:Heparin-binding EGF-like Growth Factor; D006877:Hydroxamic Acids; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D020782:Matrix Metalloproteinases / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology; D019899:Paracrine Communication / Q000502:physiology; D010766:Phosphorylation; D011799:Quinazolines; D034741:RNA, Small Interfering; D011817:Rabbits; D020032:Tyrphostins / Q000378:metabolism; D014945:Wound Healing / Q000502:physiology; D019061:src-Family Kinases / Q000378:metabolism*
D001426:Bacterial Proteins; D004151:Dipeptides; D066257:Heparin-binding EGF-like Growth Factor; D006877:Hydroxamic Acids; D036341:Intercellular Signaling Peptides and Proteins; C092152:N-((2-(hydroxyaminocarbonyl)methyl)-4-methylpentanoyl)-3-(2'-naphthyl)alanylalanine, 2-aminoethylamide; C078131:N-(2(R)-2-(hydroxamidocarbonylmethyl)-4-methylpentanoyl)-L-tryptophan methylamide; D011799:Quinazolines; D034741:RNA, Small Interfering; D020032:Tyrphostins; C028581:CRM197 (non-toxic variant of diphtheria toxin); C101044:RTKI cpd; D066246:ErbB Receptors; D019061:src-Family Kinases; D051722:ADAM Proteins; D020782:Matrix Metalloproteinases