Hepatocyte growth factor prevents acute renal failure and accelerates renal regeneration in mice

Hepatocyte growth factor gene therapy prevents radiation-induced liver damage

AIM: To transfer human HGF gene into the liver of rats by direct electroporation as a means to prevent radiation-induced liver damage.

METHODS: Rat whole liver irradiation model was accomplished by intra-operative approach. HGF plasmid was injected into liver and transferred by electroporation using a pulse generator. Control rats (n = 8) received electrogene therapy (EGT) vehicle plasmid and another 8 rats received HGF-EGT 100 μg 48 h before WLIR. Expression of HGF in liver was examined by RT-PCR and ELISA methods. Apoptosis was determined by TUNEL assay. Histopathology was evaluated 10 wk after whole liver irradiation.

RESULTS: Marked decrease of apoptotic cells and down-regulation of transforming growth factor-beta 1 (TGF-β1) mRNA were observed in the HGF-EGT group 2 d after liver irradiation compared to control animals. Less evidence of radiation-induced liver damage was observed morphologically in liver specimen 10 wk after liver irradiation and longer median survival time was observed from HGF-EGT group (14 wk) compared to control rats (5 wk). (P = 0.031).

CONCLUSION: For the first time it has been demonstrated that HGF-EGT would prevent liver from radiation-induced liver damage by preventing apoptosis and down-regulation of TGF-β1.

Flavonoid ofDrynaria fortunei protects against acute renal failure

The flavonoid fraction (FF) from Drynaria fortunei was investigated to determine its biological activity expression in three acute renal failure animal models. Guinea pigs received 100 mg/kg of gentamicin (GM group), 100 mg/kg of GM plus 10 mg/kg of FF (GMFF group), 10 mg/kg of FF (FF group) or saline (saline group) intramuscularly for 14 days. The blood urea nitrogen (BUN) and creatinine levels were found to be significantly higher in the GM group (22.70+/-3.84 mg/dL, 0.68+/-0.05 mg/dL) than in the GMFF group (17.10+/-1.04 mg/dL, 0.58+/-0.09 mg/dL), the FF group (17.40+/-1.01 mg/dL, 0.49+/-0.20 mg/dL) and the saline group (17.50+/-1.22 mg/dL, 0.50+/-0.02 mg/dL). Mice were treated once with 6 mg/kg of mercuric chloride, followed by 10 mg/kg of FF or saline. On days 3, 4 and 5, BUN and creatinine levels were found to be significantly higher in the HgCl2-saline group (74.00+/-39.20 mg/dL, 59.30+/-31.20 mg/dL, 74.00+/-37.30 mg/dL and 0.53+/-0.17 mg/dL, 0.48+/-0.15 mg/dL 0.33+/-0.15 mg/dL) than in the HgCl2-FF group (19.50+/-4.90 mg/dL, 43.00+/-26.30 mg/dL, 38.50+/-13.80 mg/dL and 0.23+/-0.05 mg/dL, 0.30+/-0.12 mg/dL, 0.15+/-0.06 mg/dL).After surgery for 5/6-nephrectomy, ten mice received FF at a dose of 10 mg/kg/day and eight received saline for 42 days. The saline group survived for 12-62 days and the FF group survived for 20-320 days. The FF group had a significantly longer survival time than the saline group (p<0.05). Regeneration of kidney tubular cells and significantly enlarged convoluted tubules were noted in the pathology study of the FF group. In conclusion, the present study suggests that FF prevents nephrotoxicity, improves kidney function and promotes kidney primary epithelial tubular cell regeneration.

Hepatocyte growth factor attenuates airway hyperresponsiveness, inflammation, and remodeling

Hepatocyte growth factor (HGF) is known to influence a number of cell types and their production of regulatory cytokines. We investigated the potential of recombinant HGF to regulate not only the development of allergic airway inflammation and airway hyperresponsiveness (AHR), but also airway remodeling in a murine model. Administration of exogenous HGF after sensitization but during ovalbumin challenge significantly prevented AHR, as well as eosinophil and lymphocyte accumulation in the airways; interleukin (IL)-4, IL-5, and IL-13 levels in bronchoalveolar lavage (BAL) fluid were also significantly reduced. Further, treatment with HGF significantly suppressed transforming growth factor-beta (TGF-beta), platelet-derived growth factor, and nerve growth factor levels in BAL fluid. The expression of TGF-beta, the development of goblet cell hyperplasia and subepithelial collagenization, and the increases in contractile elements in the lung were also reduced by recombinant HGF. Neutralization of endogenous HGF resulted in increased AHR as well as the number of eosinophils, levels of Th2 cytokines (IL-4, IL-5, and IL-13) and TGF-beta in BAL fluid. These data indicate that HGF may play an important role in the regulation of allergic airway inflammation, hyperresponsiveness, and remodeling.

Effect of hematopoietic cytokines on renal function in cisplatin-induced ARF in mice

In this study, the effect of hematopoietic cytokines, i.e., granulocyte-colony stimulating factor (G-CSF), stem cell factor (SCF), and granulocyte-macrophage-colony stimulating factor (GM-CSF), on renal function was studied in cisplatin-induced acute renal failure in mice. Treatment with G-CSF significantly ameliorated both BUN and serum creatinine increase induced by cisplatin administration with concomitant alleviation in the degree of necrotic change, enhancement in DNA synthesis, and decrease in apoptosis of renal tubular cells. There was no significant change observed among these parameters following treatment with SCF or with GM-CSF. Serum hepatocyte growth factor level was significantly lower in mice treated with cisplatin and G-CSF compared with that in those treated with cisplatin only. In conclusion, G-CSF, but not SCF or GM-CSF, acts to accelerate regeneration and prevent apoptosis of renal tubular epithelial cells and leads to reduced renal injury in cisplatin-induced acute renal failure in mice.

Prostate cancer and the met hepatocyte growth factor receptor

The hepatocyte growth factor/scatter factor (HGF/SF) and its receptor, the Met protein tyrosine kinase, form a classic ligand-receptor system for epithelial-mesenchymal communications in the normal and cancerous prostate. This review illustrates the expression and activities of HGF/SF and Met during prostate development, homeostasis, and carcinogenesis. The participation of HGF/SF in the morphogenetic program of rodent prostate development, the role of Met in normal human prostate epithelium, and underlying mechanisms of deregulated Met expression in localized and metastatic prostate cancer are discussed. On the basis of the commonly observed overexpression of Met in metastatic prostate cancer, HGF/SF-Met-targeted imaging and therapeutic agents can now be applied toward diagnosis and treatment.

Recent advances in the treatment of graft-versus-host disease

Graft-versus-host disease (GVHD) is a lethal complication of allogeneic hematopoietic stem cell transplantation (HSCT) where immunocompetent donor T cells attack the genetically disparate host cells. The predominant symptoms of acute GVHD occur in the skin, liver, and intestine. Induction of acute GVHD can be divided into three phases: recipient conditioning, donor T cell activation, and effector cell-mediated GVHD. Chronic GVHD usually appears up to 100 days after HSCT and is characterized by symptoms similar to those observed for autoimmune disease. It is possible that chronic GVHD is the result of autoreactive T cells that escaped negative selection due to damage to the thymus from conditioning regimens, acute GVHD, and/or age related atrophy. Recent advances in the understanding of the basic mechanisms involved in GVHD pathophysiology have led to new strategies designed to block GVHD. This review focuses on recent developments in the treatment of GVHD, including insights gained from our own experimental studies.

Myocardial Protective Effect of Human Recombinant Hepatocyte Growth Factor for Prolonged Heart Graft Preservation in Rats

BACKGROUND

In heart transplantation, myocardial apoptosis during hypothermic storage contributes to graft dysfunction. On the other hand, hepatocyte growth factor (HGF) has been reported to be an antiapoptotic factor in the heart. Therefore, we assessed whether the administration of recombinant human HGF (rh-HGF) prevents apoptosis in the prolonged preserved myocardium, resulting in an improvement in the cardiac function of the graft.

METHODS

Isolated rat hearts were subjected to 4 hr (group A), 6 hr (group B), and 8 hr (group C: without rh-HGF vs. group D: with 100 microg of rh-HGF) of hypothermic storage followed by 60 min of normothermic reperfusion (n=5 in each group).

RESULTS

Compared with non-HGF-treated hearts (group C), HGF-treated hearts (group D) showed a significantly higher recovery rate of left ventricular developed pressure (38+/-5% vs. 58+/-6%, P<0.01) and maximum dp/dt (53+/-7% vs. 74+/-4%, P<0.01) and a lower rate of TUNEL-positive cardiomyocytes (7.8+/-6.0% vs. 25.3+/-8.9%, P<0.05) after 60 min of reperfusion. Western blot analysis revealed that c-Met/HGF receptor expression was stronger in the HGF-treated myocardium than in the non-HGF-treated myocardium after 8 hr of storage and was associated with a weaker expression of caspase-3 and a stronger expression of Bcl-xL after 60 min of reperfusion.

CONCLUSION

The administration of rh-HGF before storage improved cardiac function after prolonged myocardial preservation by preventing apoptosis through the c-Met/HGF receptor. Thus, the addition of rh-HGF in the storage solution may be a promising strategy for prolonged heart graft preservation.

Hepatocyte growth factor suppresses vascular medial hyperplasia and matrix accumulation in advanced pulmonary hypertension of rats

BACKGROUND

Pulmonary hypertension (PH) is a progressive disease characterized by raised pulmonary vascular resistance, thought to be curable only through lung transplantation. Pathophysiologically, proliferation of pulmonary artery smooth muscle cells triggers pulmonary arterial stenosis and/or regurgitation, especially in advanced PH.

METHODS AND RESULTS

Using a rat model of advanced pulmonary vascular disease produced by injecting monocrotaline, we show that hepatocyte growth factor (HGF) targets pulmonary arterioles and blocks the progression of PH. In these rats, endogenous HGF production was dramatically downregulated during developing experimental PH, but c-Met/HGF receptor was abundant in the medial layers of pulmonary arterioles. HGF gene transfection 2 weeks after the monocrotaline injection resulted in milder medial hyperplasia in lung arterioles and inhibited overgrowth of pulmonary artery smooth muscle cells. Notably, exogenous HGF reduced lung expression levels of endothelin-1 and transforming growth factor-beta, which are critically involved in PH-linked fibrogenic events. Overall, medial wall thickening of pulmonary arteries was almost completely prevented by HGF, and the total collagen deposition in the lung decreased; both effects contributed to the suppression of pulmonary artery hypertension.

CONCLUSIONS

Our results suggest that the loss of endogenous HGF may be a feature of the pathogenesis of PH and that HGF supplementation may minimize pathological lung conditions, even advanced PH.

Cisplatin up-regulates the in vivo biosynthesis and degradation of renal polyamines and c-Myc expression

Time-dependent changes in polyamine metabolism and c-Myc expression are reported in kidney of mice treated with cisplatin, a widely used anticancer drug. We show that cisplatin significantly induces the expression of two enzymes critical to proper homeostasis of cellular polyamines, ornithine decarboxylase (ODC) and spermidine/spermine N1-acetyltransferase (SSAT). We also document the cross-talk between signalling pathway(s) induced by cisplatin injury to renal tubules and the testosterone/androgen receptor pathway. Their interaction results in a decrease in testosterone-induced ODC activity and ODC mRNA level, and in differential modulation of SSAT expression. Moreover, cisplatin and antifolate CB 3717, another nephrotoxic drug examined, severalfold up-regulate expression of c-Myc mRNA, albeit with different kinetics. However, cisplatin, contrary to CB 3717, does not induce renal hepatocyte growth factor (HGF)/c-Met expression being without effect on HGF mRNA level and significantly down-regulating c-Met transmembrane receptor message. In conclusion, these in vivo studies document significant cisplatin-induced modulation of polyamine biosynthesis/degradation and up-regulation of c-Myc expression, and suggest that c-Myc transcription factor is involved in the induction of ODC in kidney injured with antifolate, but not with cisplatin.

Hepatocyte growth factor in kidney fibrosis: therapeutic potential and mechanisms of action

Hepatocyte growth factor (HGF) is a pleiotropic factor that plays an imperative role in tubular repair and regeneration after acute renal injury. Growing evidence indicates that HGF is also an endogenous renoprotective factor that possesses a potent antifibrotic ability. HGF prevents the initiation and progression of chronic renal fibrosis and inhibits transforming growth factor (TGF)-beta(1) expression in a wide variety of animal models. In vitro, HGF counteracts the action of TGF-beta(1) in different types of kidney cells, resulting in blockade of the myofibroblastic activation from interstitial fibroblasts and glomerular mesangial cells, as well as inhibition of the mesenchymal transition from tubular epithelial cells. Recent studies reveal that HGF antagonizes the profibrotic actions of TGF-beta(1) by intercepting Smad signal transduction through diverse mechanisms. In interstitial fibroblasts, HGF blocks activated Smad-2/3 nuclear translocation, whereas it specifically upregulates the expression of the Smad transcriptional corepressor SnoN in tubular epithelial cells. In glomerular mesangial cells, HGF stabilizes another Smad corepressor, TGIF, by preventing it from degradation. Smad corepressors bind to activated Smad-2/3 and sequester their ability to transcriptionally activate TGF-beta target genes. This article reviews recent advances in our understanding of the cellular and molecular mechanisms underlying HGF inhibition of renal fibrosis.

Transgene-derived hepatocyte growth factor attenuates reactive renal fibrosis in aristolochic acid nephrotoxicity

BACKGROUND

Hepatocyte growth factor (HGF) has been demonstrated to attenuate acute tubular necrosis and interstitial fibrosis in a variety of rodent models of kidney disease. We investigated how HGF could affect chronic toxic nephropathy/interstitial fibrosis caused by aristolochic acid (AA).

METHODS

Wild-type and HGF transgenic mice received daily intraperitoneal injections of AA for 14 days. At sacrifice, kidneys were removed and used for microscopy examination and in vitro studies. To determine the molecular mechanisms of anti-fibrotic effects of HGF, cultured murine tubular epithelial cells (mProx24) were employed.

RESULTS

Significant tubular degeneration was observed in both the transgenic and the wild-type mice to the same degree after 2 weeks treatment with AA. Interstitial fibrosis subsequently developed in the wild-type mice 4 weeks after cessation of AA administration. However, the transgenic mice manifested less fibrotic changes. Decreased expression of tissue inhibitor of metalloproteinase-1 (TIMP-1) and increased matrix metalloproteinase-9 activity could partially account for the attenuation of fibrogenesis in the transgenic mouse kidney. HGF at 10 and 100 ng/ml could block TIMP-1 gene expression in mProx24 induced by epidermal growth factor, but a decrease in the number of mProx24 via apoptosis induced by AA was blocked only by HGF at 100 ng/ml.

CONCLUSION

Circulating transgene-derived HGF (2-10 ng/ml) could not prevent tubular degeneration caused by AA, but attenuated interstitial fibrogenesis during tubular regeneration. These findings suggest a possible therapeutic efficacy for renal interstitial fibrosis following tubular degeneration even of low-dose HGF.

Regression of advanced diabetic nephropathy by hepatocyte growth factor gene therapy in rats

Diabetic nephropathy is the main cause of end-stage renal disease requiring dialysis in developed countries. In this study, we demonstrated the therapeutic effect of hepatocyte growth factor (HGF) on advanced rather than early diabetic nephropathy using a rat model of streptozotocin-induced diabetes. Early diabetic nephropathy (16 weeks after induction of diabetes) was characterized by albuminuria, hyperfiltration, and glomerular hypertrophy, whereas advanced diabetic nephropathy showed prominent transforming growth factor (TGF)-beta1 upregulation, mesangial expansion, and glomerulosclerosis. An SP1017-formulated human HGF (hHGF) plasmid was administered by intramuscular injection combined with electroporation over a 30-day follow-up in rats with early and advanced diabetic nephropathy. hHGF gene therapy upregulated endogenous rat HGF in the diabetic kidney (rat HGF by RT-PCR was threefold higher than in diabetic rats without therapy). hHGF gene therapy did not improve functional or morphologic abnormalities in early diabetic nephropathy. hHGF gene therapy reduced albuminuria and induced strong regression of mesangial expansion and glomerulosclerosis in advanced diabetic nephropathy. These findings were associated with suppression of renal TGF-beta1 and mesangial connective tissue growth factor (CTGF) upregulation, inhibition of renal tissue inhibitor of metalloproteinase (TIMP)-1 expression, and reduction of renal interstitial myofibroblasts. In conclusion, our results suggest that hHGF gene therapy may be considered as an innovative therapeutic strategy to treat advanced diabetic nephropathy.

Branching morphogenesis and kidney disease

Branching morphogenesis in the kidney is a tightly regulated, complex process and its disruption potentially can lead to a broad spectrum of diseases, ranging from rare hereditary syndromes to common conditions such as hypertension and chronic kidney failure. This review synthesizes data on branching during kidney development derived from in vitro and in vivo rodent studies and to apply them to human diseases. It discusses how the broad organization of molecular interactions during kidney development might provide a mechanistic framework for understanding disorders related to aberrant branching.

Isolation and expression of five-amino-acid-deleted variant of feline hepatocyte growth factor (HGF) cDNA

Hepatocyte growth factor (HGF) is a pleiotropic cytokine that stimulates a wide array of cellular targets, including hepatocytes and other epithelial cells, melanocytes, endothelial and hematopoietic cells. We have cloned a different form of cDNA, with a deletion of 15 base pairs predicted to result in the loss of 5 amino acids from the first kringle domain. To investigate the biological activity, original and deleted variant of feline HGF cDNAs were transiently expressed in COS-7 cells. Both recombinant feline HGFs showed almost the same dose-response curves in the stimulation of the growth of BNL CL.2 cells (a mouse hepatocyte cell line) and scatter activity of Madin-Darby canine kidney (MDCK) cells. The findings reported here suggest that the deleted variant of feline HGF has almost the same biological activity as the original in terms of the proliferation and scatter activity.

Hepatocyte growth factor both prevents and ameliorates the symptoms of dermal sclerosis in a mouse model of scleroderma

Systemic sclerosis (SSc) is a connective tissue disorder with an unknown etiology. There are currently no effective therapies for SSc. (In this study, working with a bleomycin(BLM)-induced scleroderma model mice, we performed two transfections of human hepatocyte growth factor (HGF) cDNA into the skeletal muscle and showed that this treatment not only helped to prevent the dermal sclerosis simultaneously injected BLM but also improved the symptoms of dermal sclerosis induced by BLM 4 weeks previously.) RT-PCR, ELISA and an immunohistochemical analysis revealed that both mRNA and protein of human HGF as well as murine HGF were enhanced in the skin, lung, muscle and the serum after two transfections of human HGF cDNA. These analyses also revealed that this treatment significantly reduced both the expression of the TGF-beta1 mRNA and the production of TGF-beta1 on macrophage-like cells that infiltrated the dermis and the fibroblastic cells in BLM-induced scleroderma. Furthermore, HGF-gene transfection both prevented and ameliorated the symptoms of not only dermal sclerosis but also of lung fibrosis induced by a subcutaneous BLM injection. These results indicated that gene therapy by the transfection of the human HGF cDNA may thus be a useful therapy for SSc and lung fibrosis involved with SSc.

Hepatocyte growth factor regulates angiotensin converting enzyme expression

Hepatocyte growth factor (HGF) is a mitogen, morphogen, and motogen that functions in tissue healing and acts as an anti-fibrotic factor. The mechanism for this is not well understood. Recent studies implicate somatic angiotensin-converting enzyme (ACE) in fibrosis. We examined the effects of HGF on ACE expression in bovine pulmonary artery endothelial cells (BPAEC). Short term treatment of BPAEC with HGF transiently increased both ACE mRNA (3 h) and activity (24 h), as determined by ACE protease assays and reverse transcription-PCR. Incubation of BPAEC with HGF for longer periods suppressed ACE mRNA (6 h) and activity (72 h). In contrast, phorbol ester (PMA) treatment produced sustained increase in ACE mRNA and activity. We examined the short term molecular effects of HGF on ACE using PMA for comparison. HGF and PMA increased transcription from a luciferase reporter with the core ACE promoter, which contains a composite binding site for SP1/3 and Egr-1. Immunocytochemistry and electrophoretic mobility shift assay showed that both HGF and PMA increased Egr-1 binding. HGF also increased SP3 binding, as measured by EMSA. However, HGF and PMA increased the cellular activity of only Egr-1, not SP3, as measured by luciferase reporter assays. Deletion of the Egr-1 site in the reporter construct completely abrogated HGF-induced transcription but only approximately 50% of PMA-induced activity. Expression of dominant negative Egr-1 and SP3 blocked up-regulation of the ACE promoter by HGF but only reduced up-regulation by PMA. These results show that HGF transiently increases gene transcription of ACE via activation of Egr-1, whereas PMA regulation involves Egr-1 and additional factor(s).

The chemokine KC regulates HGF-stimulated epithelial cell morphogenesis

Hepatocyte growth factor (HGF) induces migration, proliferation, and branching in renal epithelial cells from the inner medullary collecting duct (mIMCD-3 cells). Microarray analysis after HGF stimulation of these cells revealed upregulation of the chemokine KC. We found that both the message and protein levels of KC are increased after HGF treatment and that mIMCD-3 cells express the KC receptor CXCR2. Treatment with KC results in stimulation of mIMCD-3 cell proliferation but has no effect on basal rates of cell migration or branching morphogenesis. In contrast to its known stimulatory effect on neutrophil migration, KC markedly inhibits HGF-mediated cell migration and branching morphogenesis, resulting in shorter tubules with fewer branch points. Examination of the mechanism of this effect reveals that KC does not alter phosphorylation of the c-met receptor or the initial activation of the MAPK or phosphoinositide 3-kinase (PI 3-K) signaling pathways. However, sustained activation of the PI 3-K pathway by HGF was inhibited by treatment with KC, and mimicking this effect by treatment with LY-294002 2 h after HGF stimulation reproduced the inhibition of HGF-stimulated branching morphogenesis. These data demonstrate that HGF-mediated KC production can act in an autocrine fashion to downregulate excessive branching and migration of renal epithelial cells in response to HGF, while still supporting cell proliferation. These characteristics may play a role in modulating the response to HGF during developmental tubule formation and/or during the repair of the tubular architecture following injury.

Hepatocyte growth factor inhibits intrinsic antibacterial activity of Madin-Darby canine kidney cells

We investigated whether or not polarized renal epithelial cells produce antibacterial factors, which aid in host defense at the cell surface of renal epithelium. A model of polarized Madin-Darby canine kidney (MDCK) epithelial cells grown on filters was used to test for the presence of apically or basolaterally secreted factors on the growth of non-virulent (XL1-Blue) and uropathogenic (J96) strains of Escherichia coli (E. coli). Growth of both XL1-Blue and J96 strains of E. coli in medium on the apical and basolateral surface of MDCK cells was inhibited as compared to bacterial growth in medium not exposed to MDCK cells. The inhibition of bacterial growth was similar in both apical and basolateral surface medium. Pretreatment of MDCK cells with hepatocyte growth factor (HGF) blunted the inhibition of XL1-Blue and J96 growth in apical and basolateral surface medium as compared to growth in medium on the surfaces of untreated MDCK cells. Immunofluorescent analysis demonstrated the presence of beta-defensin isoforms 1-3 in MDCK cells, with isoform 1 being the most prevalent form observed. HGF treatment reduced the amount of immunoreactive beta-defensin-1 in MDCK cells. These data demonstrate that polarized renal epithelium produce antibacterial factors. The renotropic growth factor HGF inhibits these antibacterial factors. beta-defensins may contribute to this antibacterial activity and play an important role in renal epithelial resistance to bacterial infections.

Suppressions of chronic glomerular injuries and TGF-β1production by HGF in attenuation of murine diabetic nephropathy

Diabetic nephropathy is now the leading cause of end-stage renal diseases, and glomerular sclerotic injury is an initial event that provokes renal dysfunction during processes of diabetes-linked kidney disease. Growing evidence shows that transforming growth factor-β1(TGF-β1) plays a key role in this process, especially in eliciting hypertrophy and matrix overaccumulation. Thus it is important to find a ligand system to antagonize the TGF-β1-mediated pathogenesis under high-glucose conditions. Herein, we provide evidence that hepatocyte growth factor (HGF) targets mesangial cells, suppresses TGF-β1production, and minimizes glomerular sclerotic changes, using streptozotocin-induced diabetic mice. In our murine model, glomerular sclerogenesis (such as tuft area expansion and collagen deposition) progressed between 6 and 10 wk after the induction of hyperglycemia, during a natural course of diabetic disease. Glomerular HGF expression levels in the diabetic kidney transiently increased but then declined below a basal level, with manifestation of glomerular sclerogenesis. When anti-HGF IgG was injected into mice for 2 wk (i.e., from weeks 4 to 6 after onset of hyperglycemia), these glomerular changes were significantly aggravated. When recombinant HGF was injected into the mice for 4 wk (i.e., between 6 and 10 wk following streptozotocin treatment), the progression of glomerular hypertrophy and sclerosis was almost completely inhibited, even though glucose levels remained unchanged (>500 mg/dl). Even more important, HGF repressed TGF-β1production in glomerular mesangial cells even under hyperglycemic conditions both in vitro and in vivo. Consequently, not only albuminuria but also tubulointerstitial fibrogenesis were attenuated by HGF. Overall, HGF therapy inhibited the onset of renal dysfunction in the diabetic mice. On the basis of these findings, we wish to emphasize that HGF plays physiological and therapeutic roles in blocking renal fibrogenesis during a course of diabetic nephropathy.

Molecular cloning, genomic structure, and expression analysis of MUC20, a novel mucin protein, up-regulated in injured kidney

Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis in the world. Here, we identify a cDNA encoding a novel mucin protein, shown previously to be up-regulated in IgAN patients, from a human kidney cDNA library. This protein contains a mucin tandem repeat of 19 amino acids consisting of many threonine, serine, and proline residues and likely to be extensively O-glycosylated; thus, this gene was classified in the mucin family and named MUC20. The human MUC20 gene contains at least four exons and is localized close to MUC4 on chromosome 3q29. We found variations in repeat numbers in the mucin tandem domain, suggesting polymorphism of this region. Northern blot and reverse transcription-PCR analyses revealed that human MUC20 mRNA was expressed most highly in kidney and moderately in placenta, colon, lung, prostate, and liver. Immunohistochemical analysis of human kidney revealed that MUC20 protein was localized in the proximal tubules. Immunoblotting analysis of MUC20 proteins produced in Madin-Darby canine kidney and HEK293 cells indicated the localization of MUC20 protein in a membrane fraction and extensive posttranslational modification. Immunoelectron microscopy of MUC20-producing Madin-Darby canine kidney cells demonstrated that MUC20 protein was localized on the plasma membrane. Expression of MUC20 mRNA in a human kidney cell line was up-regulated by tumor necrosis factor-alpha, phorbol 12-myristate 13-acetate, or lipopolysaccharide. Two species of MUC20 mRNA (hMUC20-L and hMUC20-S), resulting from alternative transcription, were identified in human tissue, whereas only one variant was observed in mouse tissues. Mouse MUC20 mRNA was expressed in the epithelial cells of proximal tubules, and the expression increased dramatically with the progression of lupus nephritis in the kidney of MRL/MpJ-lpr/lpr mice. Moreover, the expression of mouse MUC20 was augmented in renal tissues acutely injured by cisplatin or unilateral ureteral obstruction. These characteristics suggest that the production of MUC20 is correlated with development and progression of IgAN and other renal injuries.

Canine hepatocyte growth factor: molecular cloning and characterization of the recombinant protein

Hepatocyte growth factor (HGF) is a pleiotropic cytokine originally identified and cloned as a potent mitogen for hepatocytes. The HGF receptor is the transmembrane tyrosine kinase encoded by c-MET proto-oncogene. Various lines of evidence suggest that the HGF/c-MET receptor system plays essential roles in monocyte-macrophage function, mammalian development, angiogenesis and organ regeneration. We have cloned canine HGF (CaHGF) cDNA from leukocytes by the methods of reverse transcription (RT)-polymerase chain reaction (PCR) and rapid amplification of cDNA ends (RACE). Canine HGF contains an open reading frame (ORF) of 2193 nucleotides, coding for 730 amino acids. The deduced amino acid sequence of canine HGF shows 97.5, 92.3, 92.1, and 92.0% homologies with those of feline, human, mouse, and rat, respectively. The possible glycosylation sites, cysteine residues linking the alpha and beta chains and the proteolytic processing site are conserved in all species. In addition, we have found a variant cDNA that deleted a sequence of 15 base pairs in the first kringle domain (K1) and resulted in the deletion of five amino acids. To confirm the biological activities of canine HGF cDNAs, both cDNAs were transiently expressed in COS-7 cells. The conditioned medium from the canine HGF-transfected COS-7 cells stimulated the growth of BNL CL.2 cells (a mouse hepatocyte cell) and scattering activity of Madin-Darby canine kidney (MDCK) cells. The materials reported here will be a crucial resource for further studies of canine HGF.

Reciprocal functions of hepatocyte growth factor and transforming growth factor-beta1 in the progression of renal diseases: a role for CD44?

Progressive renal fibrosis occurs via common pathophysiologic mechanisms, regardless of the primary underlying disease. This cascade includes release of cytokines/chemokines and toxic molecules, interstitial inflammation, tubular cell damage, accumulation of myofibroblasts, and finally, fibrosis. Hepatocyte growth factor (HGF) and transforming growth factor-beta1 (TGF-beta1) are key molecules in this cascade that, in general, exert opposite actions. Hepatocyte growth factor promotes, to some extent, inflammation, protects tubular epithelial cells, blocks myofibroblast transition, and contributes to tissue remodeling. In contrast, TGF-beta1 has powerful anti-inflammatory actions, promotes apoptosis, induces myofibroblast transition, and is a strong pro-fibrotic agent. The mechanisms which orchestrate the reciprocal actions of HGF and TGF-beta1 are still largely unknown and are probably multiple. One of these mechanisms involves the selective up-regulation of CD44 in damaged kidney. The glomerular and tubular expression of CD44 closely correlates with the degree of renal damage, and CD44 has been shown to facilitate the action of both HGF and TGF-beta1. Moreover, during chronic obstructive nephropathy CD44 knock-out mice display much more tubular damage but develop less fibrosis in the course of the renal disease. These histologic findings are associated with impairment of signaling pathways of both HGF and TGF-beta1. The development of new therapeutic strategies aimed at preventing progression of renal diseases that are based on HGF and/or TGF-beta1 may take in account the pivotal role of CD44 expression in the functions of both molecules.

Hepatocyte growth factor gene transfer into the liver via the portal vein using electroporation attenuates rat liver cirrhosis

Although a variety of gene transfer methods to the liver have been designed, there are some problems such as the transfection efficiency and safety. In the present study, we developed a modified method of gene transfer into the liver by infusion of plasmid DNA via the portal vein followed by electroporation. After green fluorescence protein gene transfer, transgene expressions were detected in 24 h, and then maximally at 3 days, and persisted for 3 weeks. Histological analysis revealed that very mild tissue damage was induced in the liver to which electroporation was applied. In the second study, human hepatocyte growth factor (HGF) was more detected in the liver injected with 500 microg of human HGF gene than 100 microg of human HGF gene. However, serum HGF did not increase with 100 or 500 microg of human HGF gene. Moreover, 500 microg of HGF gene transfer into the liver by using this method could achieve the long survival of all dimethylnitrosamine-treated rats and attenuate the fibrous regions in the liver. These results suggest that HGF gene transfer into the liver via the portal vein using electroporation might be one of the useful methods for the treatment of various liver diseases.

Molecular mechanisms of recovery from acute renal failure

OBJECTIVES

Despite technological advances in renal replacement therapy over the past few years, acute renal failure in the intensive care unit remains associated with high morbidity and mortality rates. In this article I review recent research aimed at elucidating mechanisms of renal recovery from acute injury.

DESIGN

Review of the literature.

CONCLUSIONS

A number of peptide growth hormones are reviewed, including epidermal growth factor, insulin-like growth factor-1, thyroxine, hepatocyte growth factor, and bone morphogenetic protein-7 promote renal regeneration in model systems. Unfortunately, despite promising studies in animal models of toxin and ischemia-induced acute tubular necrosis, human studies have not shown any clinical benefit. However, several of these molecules have not been studied in clinical trials. Existing pharmacologic strategies have a limited role in renal recovery. Finally, several recent studies have focused on the effects of renal replacement therapy on renal recovery, but additional studies are needed to confirm and extend these results.

ECM homeostasis in renal diseases: a genomic approach

Chronic renal disease is in general histologically accompanied by a vast amount of scar tissue, ie glomerulosclerosis and interstitial fibrosis. Scarring results from excessive accumulation of extracellular matrix (ECM) components, a process driven by a plethora of cytokines and growth factors. Studies in experimental renal disease which target these regulators using gene therapy limit or prevent the development of scarring. This review focuses specifically on the role of transforming growth factor-beta, platelet-derived growth factor, connective tissue growth factor, hepatocyte growth factor, and epidermal growth factor. The results obtained in animal models hold promise for molecular intervention strategies in human renal disease. Microarray technology allows large-scale gene expression profiling in kidney tissue to identify common molecular pathways in a step towards discovery of new drug targets. Molecular techniques are expected to be used for diagnostic and prognostic purposes in nephrological practice to supplement renal biopsy. Several studies already show that molecular techniques might be of use in routine diagnostic practice. Improvement of diagnosis and prediction of outcome in renal patients might lead to more efficient and earlier therapeutic intervention.

Counteractive effects of HGF on PDGF-induced mesangial cell proliferation in a rat model of glomerulonephritis

Activation and proliferation of glomerular mesangial cells play an important role in the development of mesangioproliferative glomerulonephritis. We investigated the role of hepatocyte growth factor (HGF) in regulating activated mesangial cell proliferation. In glomeruli of normal rats, mesangial cells barely expressed the c-Met/HGF receptor. However, when mesangioproliferative glomerulonephritis was induced in rats by the administration of an anti-Thy 1.1 antibody, glomerular HGF expression transiently decreased along with mesangiolysis, and activation of mesangial cells was associated with upregulation of the c-Met receptor. Activated mesangial cells in culture also expressed the c-Met/HGF receptor. Although addition of HGF to cultured mesangial cells did not increase DNA synthesis, HGF did diminish PDGF-induced DNA synthesis. PDGF induced activation of ERK, which continued for at least 48 h. When PDGF and HGF were simultaneously added, HGF inhibited the prolonged activation of ERK, which suggests that early inactivation of PDGF-induced ERK may be involved in the inhibitory effect of HGF on mesangial cell proliferation. Furthermore, administration of HGF to rats with anti-Thy 1.1 nephritis resulted in a selective suppression of activated mesangial cell proliferation, and this suppressive effect was associated with attenuation of phosphorylated glomerular ERK. These results indicate that HGF counteracts PDGF-induced mesangial cell proliferation and functions as a negative regulator of activated mesangial cell proliferation.

Role for growth factors and extracellular matrix in controlling differentiation of prospectively isolated hepatic stem cells

In liver development, a number of growth factors (GFs) and components of the extracellular matrix (ECMs) lead to differentiation of liver parenchymal cells. As the liver contains many cell types, specifically investigating their functional effects on hepatic stem cell populations is difficult. Prospective isolation and clonal assays for hepatic stem cells enable the examination of direct effects of GFs and ECMs on this rare cell fraction. Using previously purified cells that fulfill the criteria for hepatic stem cells, we examined how GFs and ECMs regulate differentiation in the developing liver. We show here that hepatocyte growth factor (HGF) induced early transition of albumin (ALB)-negative stem cells to ALB-positive hepatic precursors resembling hepatoblasts and then oncostatin M (OSM) promoted their differentiation to tryptophan-2, 3-dioxygenase (TO)-positive mature hepatocytes. During this transition, ECMs were necessary for the differentiation of stem cells and precursors, but their effects were only supportive. In the first step of stem cell differentiation induced by HGF, the expression of CCAAT/enhancer binding protein (C/EBP), a basic leucine zipper transcription factor, changed dramatically. When C/EBP function was inhibited in stem cells, they stopped differentiating to hepatocyte-lineage cells and proliferated actively. These are the first findings to illustrate the mechanism of hepatic stem cell differentiation in liver development.

Hepatocyte growth factor gene therapy accelerates regeneration in cirrhotic mouse livers after hepatectomy

BACKGROUND

Impaired regeneration and dysfunction of the cirrhotic liver following partial hepatectomy (PHx) are the most serious risk factors for postoperative liver failure.

AIMS

Using naked hepatocyte growth factor (HGF) plasmid by the electroporation (EP) in vivo method, we investigated HGF for its role and mechanism of proliferation and restoration of liver mass in cirrhotic mice following PHx.

ANIMALS

Eight week old female mice were used.

METHODS

HGF plasmid 50 micro g was injected intramuscularly and transferred by EP in vivo once a week for three weeks. After establishment of carbon tetrachloride induced cirrhosis, mice underwent PHx. The HGF treated group was given naked HGF plasmid four days before PHx, and additional HGF was given once a week until they were killed, while a control group was given only empty plasmid. Mice were killed 2, 4, 10, and 14 days after PHx. Morphological and functional restoration of the liver were examined, as well as activation of mitogen activated protein kinase (MAPK) and mRNA levels of HGF activator (HGFA).

RESULTS

The HGF treated group demonstrated a continuous threefold increase in HGF levels in plasma. Therapy with HGF in cirrhotic PHx resulted in effective liver regeneration via restoration of HGFA and activation of MAPK p44/p42, accelerated normalisation of liver function, and increased collagen degradation.

CONCLUSIONS

HGF gene therapy by in vivo EP may be useful for hepatic resection in cirrhotic livers by stimulating liver proliferative and collagenolytic capacities, as well as accelerating functional recovery.

Intestinal graft-versus-host disease: mechanisms and management

Allogeneic haematopoietic stem cell transplantation remains the treatment of choice for a number of malignancies. However, graft-versus-host disease (GVHD) has long been regarded as a serious complication of this procedure. Although GVHD may affect any organ, intestinal GVHD is particularly important because of its frequency, severity and impact on the general condition of the patient. Recent studies have led to progressive elucidation of the mechanism of GVHD. Donor T cells are critical for the induction of GVHD, because depletion of T cells from bone marrow grafts effectively prevents GVHD but also results in an increase of leukaemia relapse. It has been shown that the gastrointestinal tract plays a major role in the amplification of systemic disease because gastrointestinal damage increases the translocation of endotoxins, which promotes further inflammation and additional gastrointestinal damage. Consequently, the management of intestinal GVHD (and the intestine itself) is a subject that should be highlighted. In this article, approaches to the prevention of intestinal GVHD are discussed after being classified into three categories: regimens in common clinical use, regimens under investigation and original regimens used at our hospital. The standard regimen that is used most widely for prevention of GVHD is cyclosporin plus short-term methotrexate. Corticosteroids can be added to this regimen but careful consideration of the adverse effects of these hormones should be considered. Tacrolimus is a newer, more potent alternative to cyclosporin. T-cell depletion (TCD) after transplantation has been shown to prevent acute GVHD, however, the survival benefit of TCD has not been as great as expected. Mycophenolate mofetil can be useful for the treatment of acute GVHD as part of combination therapy. Regimens currently under investigation in animal experiments include suppression of inflammatory cytokines and inhibition of T-cell activation, and, specifically at our institution, hepatocyte growth factor gene therapy. The evidence-based therapy used at our institution includes systemic antibacterial therapy (including eradication of intestinal bacteria) to prevent the intestinal translocation of lipopolysaccharide and avoid the subsequent increase of various inflammatory cytokines. In addition, because of the similarities between intestinal GVHD and ulcerative colitis, sulfasalazine, betamethasone enemas and eicosapentaenoic acid have been used to treat intestinal GVHD in some patients.

Mechanisms of renal cell repair and regeneration after acute renal failure

In many cases, acute renal failure (ARF) is the result of proximal tubular cell injury and death and can arise in a variety of clinical situations, especially following renal ischemia and drug or toxicant exposure. Although much research has focused on the cellular events leading to ARF, less emphasis has been placed on the mechanisms of renal cell repair and regeneration, although ARF is reversed in over half of those who acquire it. Studies using in vivo and in vitro models have demonstrated the importance of proliferation, migration, and repair of physiological functions of injured renal proximal tubular cells (RPTC) in the reversal of ARF. Growth factors have been shown to produce migration and proliferation of injured RPTC, although the specific mechanisms through which growth factors promote renal regeneration in vivo are unclear. Recently, interactions between integrins and extracellular matrix proteins such as collagen IV were shown to promote the repair of physiological functions in injured RPTC. Specifically, collagen IV synthesis and deposition following cellular injury restored integrin polarity and promoted repair of mitochondrial function and active Na(+) transport. Furthermore, exogenous collagen IV, but not collagen I, fibronectin, or laminin, promoted the repair of physiological functions without stimulating proliferation. These findings suggest the importance of establishing and/or maintaining collagen IV-integrin interactions in the stimulation of repair of physiological functions following sublethal cellular injury. Furthermore, the pathway that stimulates repair is distinct from that of proliferation and migration and may be a viable target for pharmacological intervention.

Role of quercetin on hepatic urea production in acute renal failure

Acute renal failure (ARF) is a serious damage of renal function induced by various nephrotoxic drugs, ischemia, bilateral urethral obstruction, trauma and unilateral nephrectomy. Dramatic clinical syndrome, azotemia, develops as a result of hypovolemia, oliguria, reduced glomerular filtration and acidosis. In addition to classic medications recent studies give more attention to beneficial effect of natural plant products as bioflavonoids. We have studied the influence of bioflavonoid, quercetin, on hepatic urea production in glycerol induced ARF in the rats. Male Sprague Dawley rats were used in the experiment. The value of urea production in the liver was determined by measuring of liver arginase activity, the terminal enzyme of urea cycle. Arginase activity was increased (p < 0.01) as well as urea level (p < 0.001) 48 h after glycerol administration. Pretreatment by quercetin suppressed the arginase activity in the liver (p < 0.05) and plasma levels of urea (p < 0.01). So, we have concluded that quercetin may be beneficial in glycerol induced ARF.

A single administration of adenoviral-mediated HGF cDNA permits survival of mice from acute hepatic failure

Heptatocyte growth factor (HGF) having a variety of biological activity was suggested as a protective agent against acute toxic hepatic injury or a potentially therapeutic agent. For the efficient in vivo application of this factor, we employed adenoviral-mediated HGF gene delivery system. In this study, we constructed E1-deleted recombinant adenovirus carrying cDNA of human HGF (Ad.hHGF) and elucidated that HGF was efficiently expressed in the liver of C57/BL mice. A mouse model of acute hepatic failure was induced by high dose (1000mg/kg) of thioacetamide (TA) administration. Mice infected with Ad.hHGF showed a dramatic resistance to TA-induced acute hepatic injury. Serum ALT was increased transiently and then the level was normalized in Ad.hHGF-infected mice with TA administration. Furthermore, the survival rate was remarkably enhanced in the mice infected with Ad.hHGF. In the histological examination, massive hepatic necrosis induced by TA was almost completely protected by HGF produced by Ad.hHGF. Our results indicate that a single dose of HGF-encoding adenoviral vector maintained liver function and prevented the progression of liver necrosis in a mouse model of acute hepatic failure.

Hepatocyte growth factor: from diagnosis to clinical applications

Hepatocyte growth factor (HGF), initially identified and molecularly cloned as a potent mitogen of primary cultured hepatocytes, has multiple activities in a variety of tissues during the course of development and also in various disease states. HGF plays key roles in the attenuation of disease progression as an intrinsic repair factor. It is also evident that HGF levels are regulated under different conditions, for example, during the course of pregnancy, aging, and disease. This review focuses on the levels of HGF in normal and pathophysiological situations and examines the relationships between HGF levels and disease, disease stage, and disease prognosis. The clinical potential of HGF as a treatment for subjects with various diseases is also given attention.

Cisplatin nephrotoxicity: molecular mechanisms

Cisplatin is one of the most widely used chemotherapeutic agents for the treatment of several human malignancies. The efficacy of cisplatin is dose dependent, but the significant risk of nephrotoxicity frequently hinders the use of higher doses to maximize its antineoplastic effects. Several advances in our understanding of the biochemical and molecular mechanisms underlying cisplatin nephrotoxicity have recently emerged, and are reviewed in this article. Evidence is presented for distinct mechanisms of cisplatin toxicity in actively dividing tumor cells versus the normally quiescent renal proximal tubular epithelial cells. The unexpected role of gamma-glutamyl transpeptidase in cisplatin nephrotoxicity is elucidated. Recent studies demonstrating the ability of proximal tubular cells to metabolize cisplatin to a nephrotoxin are reviewed. The evidence for apoptosis as a major mechanism underlying cisplatin-induced renal cell injury is presented, along with the data exploring the role of specific intracellular pathways that may mediate the programmed cell death. The information gleaned from this review may provide critical clues to novel therapeutic interventions aimed at minimizing cisplatin-induced nephrotoxicity while enhancing its antineoplastic efficacy.

Ischemic rat brain extracts induce human marrow stromal cell growth factor production

Intravenous administration of human bone marrow stromal cells (hMSCs) after middle cerebral artery occlusion (MCAo) in rats provides functional benefit. We tested the hypothesis that these functional benefits are derived in part from hMSC production of growth and trophic factors. Quantitative sandwich enzyme-linked immunosorbent assay (ELISA) of hMSCs cultured with normal and MCAo brain extracts were performed. hMSCs cultured in supernatant derived from ischemic brain extracts increased production of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF). These neurotrophins and angiogenic growth factors increased in a post-ischemia time-dependent manner. The hMSC capacity to increase expression of growth and trophic factors may be the key to the benefit provided by transplanted hMSCs in the ischemic brain.

Gene transfer of human hepatocyte growth factor into rat skin wounds mediated by liposomes coated with the sendai virus (hemagglutinating virus of Japan)

Hepatocyte growth factor (HGF) regulates cell growth, cell motility, and morphogenesis in various types of cells, including epithelial and endothelial cells, indicating that it probably promotes epithelial repair and neovascularization during wound healing. To better understand the effects of HGF on wound healing, we performed human HGF-gene transfer into skin wounds in rats. The rat HGF mRNA levels, and human and rat HGF protein concentrations in the wounds in HGF gene-transfer rats were significantly elevated at 3 days, 3 to 14 days, and 3 and 14 days after gene transfer, respectively. An expression of human HGF mRNA and protein was revealed in squamous cells in the epidermis, in endothelial cells and smooth muscle cells in blood vessels, and in fibroblasts in granulation tissues at 3, 7, and 14 days after gene transfer in HGF gene-transfer rats. The wound lesion area in HGF gene-transfer rats was significantly less than that in control rats from 3 to 7 days after gene transfer. The re-epithelialization rate, microvessel counts in granulation tissues, proliferating cell nuclear antigen index of fibroblasts in granulation tissues, and the proliferating cell nuclear antigen index in the epidermis of HGF gene-transfer rats were significantly increased at 3 and 7 days after gene transfer. Semiquantitative reverse transcriptase-polymerase chain reaction revealed that the expression levels of transforming growth factor-beta1 and Colalpha2(I) mRNAs in the wounds of HGF gene-transfer rats were significantly decreased at 7 and 14 days, respectively. The hydroxyproline concentration in the wound was significantly less in HGF gene-transfer rats than in control rats at 3 days after gene transfer. These results suggest that HGF gene transfer into a skin wound may aid re-epithelialization and neovascularization in the early phase of wound healing, and that HGF may play a role in modulating cutaneous wound healing.

Expression of hepatocyte growth factor mRNA in rat liver cirrhosis induced by N-nitrosodimethylamine as evidenced by in situ RT-PCR

Hepatocyte growth factor (HGF) is a potent inducer of hepatocyte proliferation and is expressed during liver failure. In this study we used the in situ reverse transcriptase-polymerase chain reaction (RT-PCR) method to detect HGF mRNA expression in normal rat livers and cirrhotic rat livers induced by treatment with N-nitrosodimethylamine (DMN). In normal control livers, in situ RT-PCR detected HGF mRNA expression in Ito cells and Kupffer cells, both of which showed rounded morphologies. However, in the cirrhotic livers induced by DMN, HGF mRNA-positive cells were spindle-shaped and surrounded the hepatocytes located around the sinusoids. These cells appeared to be sinusoidal endothelial cells as well as Ito and Kupffer cells. Because it has been suggested that HGF expression is related to transforming growth factor-beta (TGF-beta) levels that may play an essential role in disease progression in cirrhotic livers, TGF-beta mRNA expression in normal and cirrhotic livers was also compared using in situ RT-PCR. Our results confirmed that expression of TGF-beta mRNA co-localized with HGF mRNA expression in the cirrhotic liver.

Hepatocyte growth factor gene therapy retards the progression of chronic obstructive nephropathy

BACKGROUND

Unilateral ureteral obstruction (UUO) is characterized by progressive tubular atrophy and interstitial fibrosis. Rupture of the balance between cell proliferation and apoptosis plays a critical role in renal atrophy. Hepatocyte growth factor (HGF) is a cytokine function on cell survival and tissue regeneration. We studied the effects and possible mechanisms of HGF gene therapy on tubular cell survival and anti-fibrosis in chronic obstructed nephropathy.

METHODS

An in vivo transfection procedure of repeatedly transducing skeletal muscles with the HGF gene using liposomes containing the hemagglutinating virus of Japan (HVJ liposome) was tested on UUO rats. Expression of HGF and c-Met were examined by in situ hybridization, ELISA, or immunohistochemical staining. Interstitial fibrosis and macrophage infiltration were evaluated by Masson's Trichrome staining, alpha-smooth muscle actin and ED-1 immunostaining. Cell survival indices including proliferating cell nuclear antigen (PCNA), Bcl-2, Bcl-xL and Bax were measured by immunohistochemistry and Western blots. Apoptosis was determined by the TUNEL method.

RESULTS

After HVJ-HGF gene transfer, endogenous HGF and c-Met were up-regulated in UUO kidneys. Renal fibrosis, macrophage infiltration and tubular atrophy were suppressed both at day 14 and 28 after UUO (P < 0.05 or 0.01). Tubular cell proliferation was activated while apoptosis was inhibited, especially at the late stage of UUO. Bcl-2 was enhanced in the HGF-transfected UUO rats, while no changes of Bcl-xL and Bax were found.

CONCLUSIONS

In vivo HGF gene transfection retards the progression of chronic obstructed nephropathy and protects tubular cell survival in the long-term UUO model. Bcl-2 rather than Bcl-xL or Bax may contribute to the anti-apoptotic function of HGF.

In vivo gene transfer of hepatocyte growth factor to skeletal muscle prevents changes in rat kidneys after 5/6 nephrectomy

Hepatocyte growth factor (HGF) has been reported to be a renal regeneration factor. We previously reported that HGF acts as a renotropic factor, inducing cell recovery from ischemic injury or drug toxicity. Gene transfer by electroporation, which uses plasmid DNA as the vector, has several advantages over the conventional gene transfer method using viral vectors, inducing the ability to perform repeated transfers without apparent immunologic responses to the DNA vector. We recently demonstrated that electroporation of the HGF gene into skeletal muscle was an effective treatment for liver injury in an animal model. We presently investigated prevention of development of chronic renal disease by repetitive HGF gene transfer in rats with 5/6 nephrectomy. Hepatocyte growth factor gene transfer-treated rats showed better growth in body weight than untreated rats. Histologic changes such as glomerulosclerosis and interstitial fibrosis were significantly ameliorated by HGF gene transfer compared with untreated rats. Hepatocyte growth factor gene transfer by electroporation into skeletal muscle is feasible and effective against morphologic injury in subtotally nephrectomized rats.

Hepatocyte growth factor may accelerate healing in chronic leg ulcers: a pilot study

BACKGROUND

Hepatocyte growth factor (HGF) is a heparin-binding protein with mitogenic, motogenic and morphogenic activities for various cell types. The regenerative properties of HGF have been the object of several animal and in vitro studies in recent years.

OBJECTIVE

To investigate the physiological and therapeutic effects of HGF on chronic leg ulcers.

METHODS

HGF in gel form was locally applied, once daily for 7 days, to 15 of 19 chronic leg ulcers in 11 elderly patients. All patients had previously been treated by conventional methods and their leg ulcers had been in stable conditions for between 1 and 14 years. Any signs of allergy, discomfort or pain were reported daily. Microcirculation perfusion in the ulcers, compared to the intact contiguous skin, was determined by laser Doppler at the beginning of the study, after 1 week and again after 3 months (in seven patients). Ulcer size and characteristics were also documented.

RESULTS

It was observed that microcirculatory perfusion, which might reflect the angiogenic effect of HGF, was statistically significantly correlated (r = 0.94, p < 0.002) to ulcer area reduction in the treated ulcers. Excellent (84-100% area reduction) or partial healing (58-59%) was seen in eight out of 11 patients. No control group was included in this pilot study, which must be completed by proper control studies.

CONCLUSION

This study suggests that HGF may heal chronic leg ulcers, possibly by improving the microcirculation. Proper control studies need to be performed.

Hepatocyte growth factor as cardiovascular hormone: role of HGF in the pathogenesis of cardiovascular disease

Hepatocyte growth factor (HGF) is a mesenchyme-derived pleiotropic factor which regulates cell growth, cell motility, and morphogenesis of various types of cells, and is thus considered a humoral mediator of epithelial-mesenchymal interactions responsible for morphogenic tissue interactions during embryonic development and organogenesis. Although HGF was originally identified as a potent mitogen for hepatocytes, HGF has also been identified as a member of angiogenic growth factors. Interestingly, the presence of its specific receptor, c-met, is observed in vascular cells, endothelial cells and cardiac myocytes. In addition, the mitogenic action of HGF on human endothelial cells was most potent among growth factors. Recent studies have demonstrated the potential application of HGF to treat cardiovascular disease such as peripheral vascular disease, myocardial infarction and restenosis after angioplasty. On the other hand, serum HGF concentration was significantly correlated with blood pressure. These results suggest that HGF secretion might be elevated in response to high blood pressure as a counter-system against endothelial dysfunction, and may be considered as an index of severity of hypertension. In this review, we discussed the potential role of HGF in cardiovascular disease.

An HGF-MSP chimera disassociates the trophic properties of scatter factors from their pro-invasive activity

Hepatocyte growth factor (HGF) and macrophage-stimulating protein (MSP) have an intrinsic dual nature: they are trophic cytokines preventing apoptosis on one side and scatter factors promoting invasion on the other. For therapeutic use, their anti-apoptotic activity must be separated from their pro-invasive activity. To this end, we engineered chimeric factors containing selected functional domains of HGF and/or MSP in different combinations, and tested their biological activity. Here we present a chimeric cytokine derived from the alpha-chains of HGF and MSP, named Metron factor 1 for its ability to concomitantly activate the HGF receptor (Met) and the MSP receptor (Ron). We provide evidence that Metron factor 1 prevents apoptosis and stimulates cell proliferation at nanomolar concentrations, but is devoid of any pro-invasive activity. In an in vivo murine model of drug-induced nephrotoxicity, intravenous injection of recombinant Metron factor 1 prevented renal damage and preserved tubular integrity.

alpha-Melanocyte-simulating hormone and interleukin-10 do not protect the kidney against mercuric chloride-induced injury

The anti-inflammatory cytokines alpha-melanocyte-stimulating hormone (MSH) and interleukin (IL)-10 inhibit acute renal failure (ARF) after ischemia or cisplatin administration; however, these agents have not been tested in a pure nephrotoxic model of ARF. Therefore, we examined the effects of alpha-MSH and IL-10 in HgCl(2)-induced ARF. Mice were injected subcutaneously with HgCl(2) and then given vehicle, alpha-MSH, or IL-10 by intravenous injection. Animals were killed to study serum creatinine, histology, and myeloperoxidase activity. Treatment with either alpha-MSH or IL-10 did not alter the increase in serum creatinine, tubular damage, or leukocyte accumulation at 48 h after HgCl(2) injection. Because alpha-MSH and IL-10 are active in other injury models that involve leukocytes, we studied the time course of tubular damage and leukocyte accumulation to investigate whether leukocytes caused the tubular damage or accumulated in response to the tubular damage. Tubular damage was present in the outer stripe 12 h after HgCl(2) injection. In contrast, the number of leukocytes and renal myleoperoxidase activity were normal at 12 h but were significantly increased at 24 and 48 h after injection. We conclude that neither alpha-MSH nor IL-10 altered the course of HgCl(2)-induced renal injury. Because the tubular damage preceded leukocyte infiltration, the delayed leukocyte accumulation may play a role in the removal of necrotic tissue and/or tissue repair in HgCl(2)-induced ARF.

Scatter-factor and semaphorin receptors: cell signalling for invasive growth

Malignant disease occurs when neoplastic cells abandon their primary site of accretion, cross tissue boundaries and penetrate the vasculature to colonize distant sites. This process --metastasis--is the aberrant counterpart of a physiological programme for organ regeneration and maintenance. Scatter factors and semaphorins, together with their receptors, help to orchestrate this programme. What are the differences between physiological and pathological activation of these signalling molecules, and can we exploit them therapeutically to prevent metastasis?

Hepatocyte growth factor prevents intimal hyperplasia in rabbit carotid expanded polytetrafluoroethylene grafting

PURPOSE

The major cause of vascular prosthesis failure is anastomotic intimal hyperplasia caused by the proliferation and migration of smooth muscle cells. Hepatocyte growth factor (HGF) is an endothelium-specific growth factor that exerts a mitogenic action on endothelial cells. This study was designed to examine the effect of HGF on the suppression of intimal hyperplasia after small-caliber expanded polytetrafluoroethylene (ePTFE) grafting.

METHODS

An ePTFE graft, 2 mm in diameter and 30 mm in length, was implanted in the left common carotid arteries of Japanese white rabbits, after which the animals were fed with a 1.0% cholesterol diet. HGF was infused intravenously immediately and then every day for 7 days at doses of 0.3 mg/body (the 0.3-mg HGF group; n = 20) or 1.0 mg/body (the 1.0-mg HGF group; n = 17). A control group (n = 20) underwent infusion with saline solution. The rabbits were killed on postoperative days (PODs) 1, 2, 3, 5, 7, and 28.

RESULTS

The patency rates on POD 28 were 33%, 55%, and 100% in the control, the 0.3-mg HGF, and the 1.0-mg HGF groups, respectively, with a significant difference between the control and the 1.0-mg HGF group (P <.05). Endothelial-like cells were seen on the intraluminal surface of the graft only near the anastomotic site on POD 5 in the 1.0-mg HGF group. Intimal thickness at the distal anastomosis was 284 +/- 140 microm, 106 +/- 18 microm, and 67 +/- 10 microm in the control, the 0.3-mg HGF, and the 1.0-mg HGF groups, respectively, with a significant difference between the control and both HGF groups (P <.05). The number of anti-embryonic smooth muscle antibody positive cells at the distal anastomosis was 28.6 +/- 0.8, 3.8 +/- 2.8, and 3.9 +/- 0.9 in the control, the 0.3-mg HGF, and the 1.0-mg HGF groups, respectively, with a significant difference between the control and both HGF groups (P <.01).

CONCLUSION

HGF might suppress intimal thickness at the anastomotic site and improve the patency rate via rapid reendothelialization by POD 28 in a rabbit carotid ePTFE grafting model.

Attenuated acute liver injury in mice by naked hepatocyte growth factor gene transfer into skeletal muscle with electroporation

BACKGROUND

Hepatocyte growth factor (HGF) plays an essential role in hepatic development and regeneration, and shows proliferative and antiapoptotic activity in hepatocytes.

AIMS

To establish an effective new method for HGF gene transfer in vivo and to investigate its effects in acute experimental liver injury.

ANIMALS

Eight week old female mice were used.

METHODS

Rat HGF gene in a modified pKSCX plasmid was transferred to the tibialis anterior muscle by electroporation using a pulse generator. Four days later, plasma HGF concentrations were determined by enzyme linked immunosorbent assay every two days for three weeks. To confirm the efficacy of electroporation, a plasmid bearing green fluorescence protein (GFP) was transferred similarly. Four days after electroporation, carbon tetrachloride (CCl(4)) was administered to mice to induce acute liver injury. Plasma alanine aminotransferase (ALT) activity was measured. Hepatic apoptosis was assessed by Hoechst 33258 staining and the TUNEL method.

RESULTS

Fluorescence microscopy showed strong green fluorescence where the GFP gene had been transferred into muscle. In mice given the HGF gene, HGF in plasma was increased up to fourfold from pretreatment amounts, peaking 6-9 days after electroporation and quickly decreasing within three weeks. Compared with the group without HGF transfer, the percentage of apoptotic hepatocytes after CCl(4) intoxication was significantly lower, as was ALT activity. In addition, ALT activity normalised more rapidly in the HGF gene transfer group.

CONCLUSIONS

Naked DNA injection and transfer by electroporation efficiently brings about HGF expression in vivo, which can attenuate acute liver injury.

CD44 expression in IgA nephropathy

Immunoglobulin A (IgA) nephropathy is a frequent, chronic renal disease characterized by a broad spectrum of clinical presentations and pathologic findings. CD44, a family of type I transmembrane glycoproteins involved in cell-cell and cell-matrix interactions, may orchestrate partially the cascade of inflammation, accumulation of myofibroblasts, and fibrosis leading to end-stage renal disease. To clarify the possible role of CD44 in the progression of IgA nephropathy, the expression of CD44 in glomeruli and the tubulointerstitial compartment was analyzed in 25 renal biopsy specimens of patients with IgA nephropathy and was correlated to histopathologic, serologic, and urinary parameters. The expression of CD44 correlated significantly with the degree of glomerular and interstitial damage, even better than the accumulation of alpha-smooth muscle actin-positive myofibroblasts, which is recognized as a reliable marker for the progression of IgA nephropathy. A positive correlation also was found between proteinuria and the expression of CD44 in the tubulointerstitial compartment. The glomerular and tubulointerstitial expression of CD44 correlated with the degree of renal damage in IgA nephropathy and could be a reliable marker of the progression of IgA nephropathy. CD44 may have a pivotal role in the cascade of renal inflammation and fibrosis.

Single injection of naked plasmid encoding hepatocyte growth factor prevents cell death and ameliorates acute renal failure in mice

Hepatocyte growth factor (HGF) is a pleiotrophic factor that plays an important role in tissue repair and regeneration after injury. The expression of both HGF and its c-met receptor genes is rapidly upregulated after acute renal injury induced by folic acid. In this study, the role of exogenous HGF in preventing acute renal failure by systemic administration of naked plasmid containing human HGF cDNA driven under the cytomegalovirus promoter (pCMV-HGF) was examined in mice. Intravenous injection of pCMV-HGF plasmid produced substantial levels of human HGF protein in mouse kidneys. Simultaneous injection of HGF plasmid DNA significantly ameliorated renal dysfunctions and accelerated recovery from the acute injury induced by folic acid. Of interest, preadministration of HGF plasmid 24 h before folic acid injection dramatically protected renal epithelial cells from both apoptotic and necrotic death and preserved the structural and functional integrity of renal tubules. Expression of HGF transgene activated protein kinase B/Akt kinase and preserved prosurvival Bcl-xL protein expression in vivo. These results indicate that a single, intravenous injection of naked plasmid containing HGF gene not only promotes renal regeneration after injury but also protects tubular epithelial cells from the initial injury and cell death in the first place. These data suggest that HGF gene therapy may provide a new avenue for exploring a novel therapeutic strategy for clinical acute renal failure.