epidermal-growth-factor and Kidney-Diseases--Cystic

Renal insufficiency as a result of congenital obstructive nephropathy is a consequence of impaired renal growth: chronic unilateral ureteral obstruction (UUO) results in greater injury to the immature kidney than to the adult kidney. The neonatal kidney responds to UUO by marked activation of the renin-angiotensin system, which contributes to severe vasoconstriction and progressive interstitial fibrosis of the obstructed kidney. The latter results in part because of activation of transforming growth factor-beta 1 by angiotensin II. Chronic UUO in the neonatal rat delays maturation of the obstructed kidney, possibly in part through suppressed expression of epidermal growth factor. In addition to affecting growth factors, UUO stimulates apoptosis in the obstructed kidney, which is quantitatively greater in the neonate than in the adult. In contrast, expression of clusterin, a glycoprotein that may play a protective role in the response to UUO, is greater in the adult than in the neonatal obstructed kidney. The response of the developing kidney to UUO is similar in a number of respects to cystic kidney disease. This includes a reduction in epidermal growth factor, and increased apoptosis that may result from suppression of bcl-2, an oncoprotein that inhibits apoptosis. Improved knowledge of the cellular and molecular basis for cystic renal disorders should lead to specific intervention in fetuses and infants with congenital obstructive nephropathy, thereby improving renal growth and development.

Topics: Adult; Age Factors; Angiotensin II; Animals; Animals, Newborn; Apoptosis; Clusterin; Epidermal Growth Factor; Fibrosis; Gene Expression Regulation; Glycoproteins; Growth Substances; Hemodynamics; Humans; Infant; Infant, Newborn; Kidney; Kidney Diseases, Cystic; Mice; Mice, Knockout; Models, Biological; Molecular Chaperones; Proto-Oncogene Proteins c-bcl-2; Rats; Renin-Angiotensin System; Transforming Growth Factor beta; Ureteral Obstruction

Topics: Acute Kidney Injury; Animals; Epidermal Growth Factor; Humans; Kidney; Kidney Diseases, Cystic

Renal cyst formation is the hallmark of autosomal dominant polycystic kidney disease (ADPKD). ADPKD cyst-lining cells have an increased proliferation rate and are surrounded by an abnormal extracellular matrix (ECM). We have previously shown that Laminin 5 (Ln-5, a alpha(3)beta(3)gamma(2) trimer) is aberrantly expressed in the pericystic ECM of ADPKD kidneys. We report that ADPKD cells in primary cultures produce and secrete Ln-5 that is incorporated to the pericystic ECM in an in vitro model of cystogenesis. In monolayers, purified Ln-5 induces ERK activation and proliferation of ADPKD cells, whereas upon epidermal growth factor stimulation blocking endogenously produced Ln-5 with anti-gamma(2) chain antibody reduces the sustained ERK activation and inhibits proliferation. In three-dimensional gel culture, addition of purified Ln-5 stimulates cell proliferation and cyst formation, whereas blocking endogenous Ln-5 strongly inhibits cyst formation. Ligation of alpha(6)beta(4) integrin, a major Ln-5 receptor aberrantly expressed by ADPKD cells, induces beta(4) integrin phosphorylation, ERK activation, cell proliferation, and cyst formation. These findings indicate that Ln-5 is an important regulator of ADPKD cell proliferation and cystogenesis and suggest that Ln-5 gamma(2) chain and Ln-5-alpha(6)beta(4) integrin interaction both contribute to these phenotypic changes.

Topics: Cell Line; Cell Proliferation; Dimerization; Epidermal Growth Factor; Extracellular Signal-Regulated MAP Kinases; Gene Expression Regulation; Humans; Integrin alpha6beta4; Kidney Diseases, Cystic; Laminin; Microscopy, Phase-Contrast; Phosphorylation; Polycystic Kidney Diseases; Protein Binding

Transforming growth factor-alpha (TGF-alpha) is abnormally expressed in autosomal recessive polycystic kidney disease (ARPKD). Tumor necrosis factor-alpha converting enzyme (TACE), a metalloproteinase, mediates TGF-alpha processing. In this study, we sought to determine whether TGF-alpha was an absolute requirement for renal cystogenesis and whether its absence would modulate disease severity or related growth factors/receptors expression. Bpk heterozygotes were bred with TGF-alpha null mice to produce cystic and noncystic offspring with or without TGF-alpha. Assessments included kidney weight (KW), body weight (BW), blood urea nitrogen (BUN), and kidney and liver immunohistology. Western analysis assessed kidney expression of amphiregulin (AR), epidermal growth factor (EGF), heparin-binding EGF (HB-EGF), and their receptors, EGFR and ErbB4. A PCR-based methodology for genotyping bpk mice was also developed. No significant differences in KW, BW, KW/BW%, or BUN were seen in cystic mice with versus without TGF-alpha. Cystic kidney disease and liver disease histology were similar. AR, EGF, HB-EGF, EGFR, and ErbB4 were abnormally expressed to an equal degree in kidneys of mice with versus without TGF-alpha. Although previous data suggest a critical role of TGF-alpha in murine PKD, these data show that TGF-alpha is not required for renal cyst formation or kidney or liver disease progression. We speculate that the therapeutic effect of WTACE2 could have been due to effects on several TACE targets, including TGF-alpha, AR, and ErbB4, as well as metalloproteinases other than TACE.

Topics: ADAM Proteins; ADAM17 Protein; Alleles; Amphiregulin; Animals; Blood Urea Nitrogen; Body Weight; Disease Progression; EGF Family of Proteins; Epidermal Growth Factor; ErbB Receptors; Genes, Recessive; Genotype; Glycoproteins; Heparin-binding EGF-like Growth Factor; Intercellular Signaling Peptides and Proteins; Kidney; Kidney Diseases, Cystic; Liver; Metalloendopeptidases; Mice; Mice, Inbred C57BL; Mutation; Organ Size; Phenotype; Polycystic Kidney Diseases; Polymerase Chain Reaction; Receptor, ErbB-4; Transforming Growth Factor alpha

We compared cytokine levels in fluid from renal cysts with and without renal cell carcinoma.. Fluid was aspirated from 18 renal cysts without (benign) and 21 with renal cell carcinoma (malignant). Serum from patients with renal cell carcinoma and healthy controls was collected and cytokines were measured by enzyme-linked immunosorbent assay.. Interleukin-6 (IL-6) and basic fibroblast growth factor concentrations were higher in malignant than benign cysts or serum (p <0.006). Epidermal growth factor levels were significantly higher in malignant cysts and serum than in benign cysts (p <0.01). IL-6 levels in malignant cysts positively correlated with the erythrocyte sedimentation rate (R=0.80) and C-reactive protein (R=0.86), and they were higher in grade 3 than in grade 2 tumors. Basic fibroblast growth factor levels were significantly higher in malignant cysts associated with hypervascular than hypovascular tumors (p=0.029).. Cytokine levels in aspirated fluid may help to identify malignant renal cysts and indicate the characteristics of coexisting tumors.

Topics: Adult; Aged; Aged, 80 and over; Biomarkers; Carcinoma, Renal Cell; Cytokines; Epidermal Growth Factor; Female; Fibroblast Growth Factor 2; Humans; Interleukin-6; Kidney Diseases, Cystic; Kidney Neoplasms; Male; Middle Aged

Simple renal cysts are commonly observed in the elderly, but few examinations have been performed to study the mechanism of this disease. We have previously shown that simple renal cyst fluid contains some growth factors, including epidermal growth factor (EGF; less than 54 pg mL-1) and insulin-like growth factor I (IGF-I; 30-2070 pg mL-1) (M. Taide et al. Clin Chim Acta, 1993; 217:199-203). In this report, the biological significance of growth factors or of human simple renal cyst fluid on the formation of renal epithelial cyst was determined using Madin-Darby canine kidney (MDCK) cells cultured in collagen gel. Both EGF (200 pg mL-1 or more) and IGF-I (100 pg mL-1 or more) were found to stimulate cyst formation in MDCK cells. Additionally, 12/21 human simple renal cyst fluid samples were found to be capable of stimulating cyst formation in MDCK cells. This activity was due to a heat- and acid-labile protein and not inhibited by the anti-IGF-I neutralizing antibody. These results indicate that in some instances simple renal cyst fluid would thus appear to contain specific activity for cyst formation, which may affect cyst formation in vivo.

Topics: Animals; Cells, Cultured; Dogs; Epidermal Growth Factor; Extracellular Space; Hot Temperature; Hydrochloric Acid; Kidney Diseases, Cystic; Papain; Somatomedins; Transforming Growth Factor beta

Progressive human renal cystic diseases are characterized by proliferation of the epithelial cells lining the cyst. The kidney synthesizes epidermal growth factor and its presence in renal cyst fluid might contribute to renal epithelial cell proliferation. We screened autosomal dominant polycystic kidney disease, acquired renal cystic disease, the von Hippel-Lindau syndrome, multilocular cystic nephroma, multicystic dysplastic kidney disease and simple cyst fluids for the presence of epidermal growth factor by radioreceptor assay, specific radioimmunoassay, immunoprecipitation and immunoblotting. Multiple epidermal growth factor immunoreactive species of approximately 180 kD. and lower molecular weights were present in almost all cyst fluids examined, suggesting endogenous synthesis and limited proteolysis of epidermal growth factor precursor protein in cyst fluid. Tamm-Horsfall protein was detected by enzyme-linked immunosorbent assay in most cysts (for example 55 of 59 autosomal dominant polycystic kidney disease samples). The majority of simple and autosomal dominant polycystic kidney disease renal cysts contained high sodium ion concentration, epidermal growth factor precursor protein and Tamm-Horsfall protein, characteristic of the early thick ascending limb. Rather than the mere presence of epidermal growth factor in renal cyst fluids, increased sensitivity to epidermal growth factor or other mitogens present in renal cyst fluid may be pathogenic in progressive renal cystic disease.

Topics: Epidermal Growth Factor; Humans; Kidney Diseases, Cystic; Mucoproteins; Protein Precursors; Sodium; Uromodulin; von Hippel-Lindau Disease

Acquired renal cysts derive from terminally differentiated tubular epithelium in adults as a consequence of increased epithelial cell proliferation, fluid accumulation and extracellular matrix remodelling. To understand better how human epithelial cysts may be initiated and progressively expand, cells from primary cultures of normal human adult renal cortex were dispersed in polymerized type I collagen. The transparent matrix permitted repeated observation by light microscopy of cyst formation from individual renal cells. The cyst cells reacted strongly with distal nephron histochemical markers (cytokeratin antibodies AE1/AE3, epithelial membrane antigen, and Arachis hypogaea lectin) but inconsistently or not at all to markers of proximal tubules (Tetragonolobus purpureas lectin and Phaseolus vulgaris erthroagglutinin lectin). The number of spherical, fluid-filled epithelial cysts that developed in a standardized microscope field quantified cyst initiation. Cyst progression was determined from the increase in the diameter (surface area) of cysts and represents a hyperplastic event. EGF or TGF alpha, were required in serum-free defined medium to cause cysts to develop from individual epithelial cells dispersed in the matrix; insulin was required as a co-factor. The EC50 for EGF was approximately 0.1 ng/ml, and for insulin 1 microgram/ml. Early cultures of normal cortex formed cysts more efficiently when dispersed in collagen matrix than cells passaged several times before suspension in the gel. Agonists of adenylate cyclase (PGE1, AVP, VIP, PTH, forskolin, cholera toxin), methylisobutylxanthine, and 8-Br-cAMP, though incapable of causing cyst formation alone in defined medium, enhanced cyst initiation and progression in the presence of EGF and insulin. Angiotensin II, TNF alpha, beta-estradiol, and pertussis toxin had no effect in the absence or presence of EGF and insulin. Pertussis toxin inhibited cyst initiation and expansion caused by EGF and forskolin but potentiated cyst initiation and expansion caused by EGF and PGE1. Cyst formation and expansion were inhibited by TGF beta 1 and 2-chloroadenosine. Polarized monolayers of human renal cortical cells grown on permeable membranes were used to independently quantify the effects of agonists on the net secretion of solute and water from the basolateral to the apical surface of the cells. PGE1, forskolin, and 8-Br-cAMP stimulated net fluid secretion that was sustained for several days; EGF enhanced forskoli

Topics: Body Fluids; Collagen; Culture Media; Culture Techniques; Cyclic AMP; Epidermal Growth Factor; Epithelium; Humans; Insulin; Kidney Cortex; Kidney Diseases, Cystic; Transforming Growth Factors

Cystic kidneys of the C57BL/6J-cpk murine model of polycystic kidney disease show a marked overexpression of the proto-oncogenes c-fos, c-myc, and c-Ki-ras, consistent with an increased rate of cell proliferation and an altered state of differentiation. To determine if cystic cells have increased responsiveness to stimulation with mitogenic agents, quiescent primary cultures from normal and cystic cpk kidneys were treated with fetal bovine serum (FBS), 8-bromo-cAMP (cAMP), or epidermal growth factor (EGF). The level of c-fos induction following stimulation by FBS was found to be dramatically higher in cystic cells than in normal cells; whereas induction by cAMP or EGF was essentially the same in both cell types and much less than that seen in FBS-stimulated cells. To determine if this serum hypersensitivity reflects an increased proliferative state in vivo, c-fos induction was examined in cultures derived from normal kidneys stimulated to regenerate by folic acid-induced acute renal injury. As with cystic kidneys, the folic acid-injured kidneys showed increased c-fos responsiveness to FBS in cell culture. These experiments suggest that cystic and regenerating kidneys have an altered phenotypic state in vivo that is manifested in cell culture by serum hypersensitivity. However, whereas the folic acid-injured kidneys ultimately reestablish normal kidney function, cystic kidneys further progress to renal failure, suggesting that cystic epithelial cells are locked in this altered state of differentiation.

Topics: 8-Bromo Cyclic Adenosine Monophosphate; Animals; Blood; Cell Division; Cells, Cultured; Culture Media; Epidermal Growth Factor; Folic Acid; Gene Expression Regulation; Genes, fos; Kidney; Kidney Diseases, Cystic; Kidney Tubules, Collecting; Mice; Mice, Inbred C57BL; RNA, Messenger

Topics: Culture Media; Cyclic AMP; Epidermal Growth Factor; Epithelial Cells; Humans; In Vitro Techniques; Kidney Cortex; Kidney Diseases, Cystic