Partial purification and characterization of hepatocyte growth factor from serum of hepatectomized rats

Effects of hepatocyte growth factor on collagen synthesis and matrix metalloproteinase production in keloids

Keloids are pathologic proliferations of the dermal layer of the skin resulting from excessive collagen production and deposition. Hepatocyte growth factor (HGF) increases the expression of matrix metalloproteinase (MMP)-1 and suppresses collagen synthesis to modulate extracellular matrix turnover. To investigate the anti-fibrotic effects of HGF, we examine the mRNA expression of collagen types I and III and matrix metalloproteinase (MMP-1, MMP-3) on human dermal fibroblast (HDF) cell lines and keloid fibroblasts (KFs, n = 5) after adding various amount of HGF protein. We also evaluated the enzymatic activity of MMP-2, MMP-9 by zymograghy. In HDFs treated with TGF-β1 and HGF protein simultaneously, both type I and III collagen mRNA expression significantly decreased (P < 0.05). Expression of MMP-1, MMP-3 mRNA also decreased. However, the mRNA expression of MMP-1, MMP-3 significantly increased in KFs with increasing amount of HGF in dose dependent manner (P < 0.05). The enzymatic activities of MMP-2 increased with increasing HGF protein in a dose-dependent manner. However, the enzymatic activity of MMP-9 did not change. These results suggest that the anti-fibrotic effects of HGF may have therapeutic effects on keloids by reversing pathologic fibrosis.

Ferritin/alanine aminotransferase ratio as a possible marker for predicting the prognosis of acute liver injury

BACKGROUND AND AIMS

  Serum levels of ferritin and heme oxygenase (HO)-1 are both markers of macrophage activation. We evaluated simple markers for predicting the prognosis of severe acute liver injury in which macrophage activation plays an important role.

METHODS

  Subjects comprised 114 patients with acute liver injury, admitted to the liver unit of Nagasaki Medical Center between January 2001 and September 2010. Subjects included 11 patients with fulminant hepatic failure (FHF), 82 patients with ordinary acute hepatitis (AH), and 21 patients with severe-form AH (AHS). We determined serum levels of ferritin, HO-1 and other biochemical makers, and analyzed relationships between clinical outcomes of patients and each of these parameters alone and in combination.

RESULTS

  Median serum ferritin levels were significantly higher in FHF (25900ng/mL) and AHS (3060ng/mL) than in AH (700ng/mL; P<0.01 each). Median HO-1 levels were also significantly higher in FHF (123ng/mL) and AHS (51ng/mL) than in AH (19ng/mL; P<0.01 each). Similarly, median ferritin/alanine aminotransferase (F/A) ratio was significantly higher in FHF (6.7) than in AHS (1.6, P<0.05) or AH (0.5, P<0.01). Among the 11 FHF patients, three recovered, seven died and one underwent liver transplantation. The ability of F/A ratio to distinguish non-survivors from survivors was analyzed using receiver operating characteristics curves. A cut-off level of 3.12 provided high sensitivity (87.5%) and specificity (81.2%).

CONCLUSION

  These results suggest that F/A ratio offer a quick and simple marker for predicting the prognosis of acute liver injury.

A novel role for Bruton's tyrosine kinase in hepatocyte growth factor-mediated immunoregulation of dendritic cells

The limited success of dendritic cell (DC)-based immunotherapy in multiple myeloma is partly due to hepatocyte growth factor (HGF)-induced DC dysfunction. From a therapeutic standpoint, it is important to understand the molecular events involved in inhibition of DC activation/maturation by HGF. Because Bruton's tyrosine kinase (Btk) negatively regulates maturation and immunostimulatory function of DCs, a role for Btk in HGF-induced inhibition of both murine and human DCs was investigated. We demonstrate that Btk is a novel proximal component of HGF-induced c-MET (HGF receptor) signaling. Following HGF treatment, Btk binds to c-MET and becomes activated. Btk activation in turn blocks the NF-κB pathway and subsequent DC activation via the c-Src-PI3K-AKT-mammalian target of rapamycin (mTOR) pathway. Notably, Btk activation is necessary for HGF-induced association of c-Src and PI3K with c-MET. Furthermore, we provide the first evidence that HGF inhibits DC activation by inducing autocrine interleukin (IL)-10 secretion, which requires activation of Btk. Blocking activation of Btk and its downstream the c-Src-PI3K-AKT-mTOR pathway prevents HGF-induced IL-10 secretion by DCs. In addition, neutralization of IL-10 secretion from DCs impaired the inhibitory effect of HGF on DCs. Thus, our study identifies a novel role for Btk in HGF-induced DC inhibition.

Development of c-MET pathway inhibitors

INTRODUCTION

The aberrantly upregulated c-mesenchymal-epithelia transition factor (c-MET) signaling pathway has been considered to be an attractive target for cancer intervention owing to the important roles it plays in tumor formation, progression, metastasis, angiogenesis and drug resistance. Based on the historical preclinical evidence, a number of c-MET pathway targeted agents are being developed in the clinic, and recent clinical data have begun to provide some insight into which tumor types and patient populations a c-MET pathway inhibitor may be beneficial for.

AREAS COVERED

Through reviewing recent publications in the literature and information disclosed in other public forums, we describe the current understanding of c-MET biology in human malignancies and discuss the latest progress in the development of c-MET pathway inhibitors for cancer treatment.

EXPERT OPINION

The c-MET pathway inhibitors currently being evaluated in the clinic have demonstrated compelling evidence of clinical activity in different cancer types and may provide significant therapeutic opportunities. The challenges, however, are to identify the tumor types and patient populations that benefit most, and find the most effective combinations of therapies while minimizing potential toxicity.

Promotion of rabbit ligament healing by local delivery of hepatocyte growth factor

BACKGROUND

Extracapsular ligament injuries of the knee and ankle are common injuries. Ligaments heal slowly, usually over months or longer by scar formation rather than by tissue regeneration. This study was performed to evaluate the therapeutic effect of locally delivered recombinant hepatocyte growth factor (HGF) on the early healing of ligaments in a rabbit model.

METHODS

Japanese white rabbits were subjected to a standardized gap injury in the medial collateral ligaments (MCLs) of both knees. Each rabbit underwent bilateral transection of the midsubstance of the MCL, which was not repaired. During postoperative days 0-6, the rabbits were injected with 10 μg human recombinant HGF into the right MCL, while the left MCL was injected with saline alone. One, 3, 6, and 12 weeks after surgery, experimental rabbits were sacrificed. The structural properties of the femur-MCL-tibia complex were then assessed and the tissue was subjected to histological evaluation. To see the distribution of cells that express c-Met receptor, the tissue was subjected to immunohistochemistry.

RESULTS

Immunohistochemical evaluation revealed that c-Met expression was observed particularly at opposing ligament ends in the HGF-treated limbs 1 week after surgery. Histological evaluation revealed earlier neovascularization and more aligned collagen fibers in the MCLs of the HGF-treated group than the control group. In mechanical evaluations, similar ligament failure modes were noted in the two groups. After 3 weeks, HGF-treated limbs had significantly improved structural properties than the paired control limbs.

CONCLUSIONS

Our findings indicate local administration of recombinant HGF promotes early steps in ligament healing and the repair of structural properties in a rabbit model. Local administration of HGF may represent a new therapeutic approach to accelerating healing and rehabilitation after ligament injury.

Motor neuron trophic factors: therapeutic use in ALS?

The modest effects of neurotrophic factor (NTF) treatment on lifespan in both animal models and clinical studies of Amyotropic Lateral Sclerosis (ALS) may result from any one or combination of the four following explanations: 1.) NTFs block cell death in some physiological contexts but not in ALS; 2.) NTFs do not rescue motoneurons (MNs) from death in any physiological context; 3.) NTFs block cell death in ALS but to no avail; and 4.) NTFs are physiologically effective but limited by pharmacokinetic constraints. The object of this review is to critically evaluate the role of both NTFs and the intracellular cell death pathway itself in regulating the survival of spinal and cranial (lower) MNs during development, after injury and in response to disease. Because the role of molecules mediating MN survival has been most clearly resolved by the in vivo analysis of genetically engineered mice, this review will focus on studies of such mice expressing reporter, null or other mutant alleles of NTFs, NTF receptors, cell death or ALS-associated genes.

Preservations of nephrin and synaptopodin by recombinant hepatocyte growth factor in podocytes for the attenuations of foot process injury and albuminuria in nephritic mice

AIM

Podocytes provide a slit diaphragm to inhibit proteinuria, and nephrin between podocytes functions as a barrier during glomerular filtration. Hepatocyte growth factor (HGF) can improve proteinuria in rodents with various renal injuries, but little is known about the role of HGF in podocyte-based events during glomerulonephritis. In the present study, we examined whether and how nephrin expression is sustained by podocytes during the HGF-mediated attenuation of albuminuria.

METHODS

Lipopolysaccharide (LPS)-treated mice were used as an animal model of albuminuria. We evaluated the effect of HGF on slit proteins using immunohistochemistry, western blotting and real-time polymerase chain reaction.

RESULTS

Albuminuria occurred 36 h after LPS treatment in mice. This albuminuria did not involve podocyte loss, but was associated with a decrease in nephrin and its key anchor, synaptopodin. In these processes, c-Met tyrosine phosphorylation, which represented HGF signal activation, occurred in glomerular cells including podocytes. When recombinant HGF was administrated to nephritic mice, c-Met tyrosine phosphorylation became evident in podocytes. The enhancement of the HGF-c-Met signal was associated with increases in nephrin and synaptopodin. An electron microscopic examination revealed that LPS induced the foot process effacement of podocytes, while HGF injections suppressed the foot process injury. Overall, albuminuria was attenuated in the LPS-treated mice after HGF administration.

CONCLUSION

HGF protects podocytes from a loss of nephrin, at least in part, through maintaining synaptopodin. As a result, HGF was shown to sustain foot process structure, and albuminuria was attenuated under inflammation.

Hepatocyte growth factor incorporated into herpes simplex virus vector accelerates facial nerve regeneration after crush injury

Hepatocyte growth factor (HGF) promotes regeneration of the central nervous system, but its effects on the peripheral nervous system remain unclear. This study was conducted to elucidate the effect of HGF on regeneration of the murine facial nerve after crush injury. To do so, a replication-defective herpes simplex virus vector that incorporated HGF was prepared (HSV-HGF). The main trunk of the facial nerve was compressed by mosquito hemostats, and HSV-HGF, control vector or medium was then applied to the compressed nerve. We found that mice in the HGF group required significantly fewer days for complete recovery from nerve compression. Furthermore, the amplitude of the evoked buccinator muscle compound action potential increased following HSV-HGF application. HGF expression in and around the compressed nerve was demonstrated by enzyme-linked immunoassay and immunohistochemistry. In addition, HSV-HGF introduction around the damaged nerve significantly accelerated recovery of function of the facial nerve. These data suggest a possible role of HGF in promoting facial nerve regeneration after nerve damage. Furthermore, this viral delivery method may be applied clinically for many types of severe facial palsy during facial nerve decompression surgery.

Is a regenerative approach viable for the treatment of COPD?

Degenerative lung diseases such as chronic obstructive pulmonary disease (COPD) are common with huge worldwide morbidity. Anti-inflammatory drug development strategies have proved disappointing and current treatment is aimed at symptomatic relief. Only lung transplantation with all its attendant difficulties offers hope of cure and the outlook for affected patients is bleak. Lung regeneration therapies aim to reverse the structural and functional deficits in COPD either by delivery of exogenous lung cells to replace lost tissue, delivery of exogenous stem cells to induce a local paracrine effect probably through an anti-inflammatory action or by the administration of small molecules to stimulate the endogenous regenerative ability of lung cells. In animal models of emphysema and disrupted alveolar development each of these strategies has shown some success but there are potential tumour-inducing dangers with a cellular approach. Small molecules such as all-trans retinoic acid have been successful in animal models although the mechanism is not completely understood. There are currently two Pharma-sponsored trials in progress concerning patients with COPD, one of a specific retinoic acid receptor gamma agonist and another using mesenchymal stem cells.

Hepatocyte growth factor-induced c-Src-phosphatidylinositol 3-kinase-AKT-mammalian target of rapamycin pathway inhibits dendritic cell activation by blocking IκB kinase activity

Hepatocyte growth factor modulates activation and antigen-presenting cell function of dendritic cells. However, the molecular basis for immunoregulation of dendritic cells by hepatocyte growth factor is undefined. In the current study, we demonstrate that hepatocyte growth factor exhibits inhibitory effect on dendritic cell activation by blocking IκB kinase activity and subsequent nuclear factor-κB activation. Inhibition of IκB kinase is mediated by hepatocyte growth factor-induced activation of c-Src. Proximal signaling events induced in dendritic cells by hepatocyte growth factor include a physical association of c-Src with the hepatocyte growth factor receptor c-MET and concomitant activation of c-Src. Activation of c-Src in turn establishes a complex consisting of phosphatidylinositol 3-kinase and c-MET, and promotes downstream activation of the phosphatidylinositol 3-kinase/AKT pathway and mammalian target of rapamycin. Blocking activation of c-Src, phosphatidylinositol 3-kinase and mammalian target of rapamycin prevents hepatocyte growth factor-induced inhibition of IκB kinase, nuclear factor-κB and dendritic cell activation. Notably, hepatocyte growth factor-stimulated c-Src activation results in induction of phosphatidylinositol 3-kinase complexes p85α/p110α and p85α/p110δ, which is required for activation of mammalian target of rapamycin, and consequent inhibition of IκB kinase and nuclear factor-κB activation. Our findings, for the first time, have identified the c-Src-phosphatidylinositol 3-kinase-AKT-mammalian target of rapamycin pathway that plays a pivotal role in mediating the inhibitory effects of hepatocyte growth factor on dendritic cell activation by blocking nuclear factor-κB signaling.

Met receptors induce Sam68-dependent cell migration by activation of alternate extracellular signal-regulated kinase family members

The hepatocyte growth factor (HGF)/Met receptor signaling pathway is deregulated in diverse human malignancies and plays a central role in oncogenesis, tumor progression, and invasive cancer growth. Similarly, altered expression and splicing (i.e. inclusion of variant exon 5, "v5") of the cell adhesion marker, CD44, is associated with advanced cancer phenotypes. We sought to further understand how HGF regulates CD44v5 expression. Immortalized nontumorigenic keratinocyte (HaCaT) cells abundantly express both Met receptors and CD44v5 transmembrane glycoproteins. HGF stimulated CD44v5 protein expression and HaCaT cell migration; these events required activation of the ERK1/2 MAPK module and Sam68, a protein involved in RNA processing, splicing, and v5 inclusion. Similar to HaCaT cells, highly migratory MDA-MB-231 breast cancer cells also required Sam68 expression for HGF-induced migration. However, MDA-MB-231 cell migration occurred independently of ERK1/2 and CD44v5 expression and instead required ERK5 signaling to Sam68. Phospho-mutant, but not WT-Sam68, blocked HGF-induced cell migration in both cell types; MDA-MB-435 cells behaved similarly. These results suggest that Sam68 acts as a convergence point for ERK signaling to cell migration; blockade of phospho-Sam68 may provide a new avenue for therapeutic inhibition of metastatic cancers.

Molecular basis of lung tissue regeneration

Recent advances have expanded our understanding of lung endogenous stem cells, and this knowledge provides us with new ideas for future regenerative therapy for lung diseases. In studies using animal models for lung regeneration, compensatory lung growth, and lung repair, promising reagents for lung regeneration have been discovered. Stem or progenitor cells are needed for alveolar regeneration, lung growth, and lung repair after injury. Endogenous progenitor cells mainly participate in alveologenesis. However, human lung endogenous progenitor cells have not yet been clearly defined. Recently discovered human alveolar epithelial progenitor cells may give us a new perspective for understanding the pathogenesis of lung diseases. In parallel with such basic research, projects geared toward clinical application are proceeding. Cell therapy using mesenchymal stem cells to treat acute lung injury is one of the promising areas for this research. The creation of bioartificial lungs, which are based on decellularized lungs, is another interesting approach for future clinical applications. Although lungs are the most challenging organ for regenerative medicine, our cumulative knowledge of lung regeneration and of endogenous progenitor cells makes clear the possibilities and limitations of regenerative medicine for lung diseases.

Minimally invasive colorectal resection is associated with a transient increase in plasma hepatocyte growth factor levels early after surgery for colon cancer

INTRODUCTION

Surgery's impact on blood levels of hepatocyte growth factor (HGF), a potent angiogenic factor, is unknown. Preoperative (PreOp) HGF blood levels are elevated in patients with colorectal cancer (CRC) and correlate with disease stage and prognosis. This study's purpose was to determine plasma HGF levels after minimally invasive colorectal resection (MICR) in patients with CRC.

METHODS

Clinical and operative data were collected. Blood samples were obtained in all patients PreOp and on postoperative day (POD) 1 and 3; in some, samples were taken during weeks 2 and 3 after MICR. Late samples were bundled into 7-day time blocks. HGF levels were determined via enzyme-linked immunosorbent assay in duplicate. Student's t test was used to analyze the data (significance, P < .0125 after Bonferroni correction).

RESULTS

A total of 28 CRC patients who underwent MICR were studied. Most had right, sigmoid, or left segmental colectomy. The mean plasma HGF level was higher on POD 1 (2417 ± 1476 pg/mL, P < .001) and POD 3 (2081 ± 1048 pg/mL, P < .001) when compared with PreOp levels (1045 ± 406 pg/mL). Plasma levels were back to baseline by the second (1100 ± 474 pg/mL, P = .64) and third postoperative weeks (1010 ± 327 pg/mL, P = .51).

CONCLUSION

MICR for CRC is associated with a 1.9- to 2.3-fold increase in plasma HGF levels during the first 3 PODs after which levels normalize. This transient increase may briefly promote angiogenesis and the growth of residual tumor cells.

Reaction of plasma hepatocyte growth factor levels in non-small cell lung cancer patients treated with EGFR-TKIs

Hepatocyte growth factor induces resistance to epidermal growth factor receptor tyrosine kinase inhibitors. It has been hypothesized that epidermal growth factor receptor tyrosine kinase inhibitors administration may influence the levels of plasma hepatocyte growth factor. Patients with advanced non-small cell lung cancer and relapsed after chemotherapies were eligible. Plasma hepatocyte growth factor levels were analyzed on pretreatment and post-treatment day 15 and 30. We also investigated the correlation between plasma hepatocyte growth factor levels and sensitivity to epidermal growth factor receptor tyrosine kinase inhibitors, tissue immunoreactivity for hepatocyte growth factor and MET gene status. Thirty-one patients were enrolled. Plasma hepatocyte growth factor levels on post-treatment day 15 (630.1 ± 366.9 pg/ml) were significantly higher (p = 0.029) than the pretreatment plasma hepatocyte growth factor levels (485.9 ± 230.2 pg/ml). Plasma hepatocyte growth factor levels on the post-treatment day 30 (581.5 ± 298.1 pg/ml) tend to be higher than those before treatment (p = 0.057). Pretreatment plasma hepatocyte growth factor levels in patients with progressive disease (724.1 ± 216.4 pg/ml) were significantly higher than those in patients with stable disease (396.5 ± 148.3 pg/ml; p = 0.0008) and partial response (381.7 ± 179.0 pg/ml; p = 0.0039). The optimal pretreatment plasma hepatocyte growth factor cut-off value for diagnosis of responder was 553.5 pg/ml, and its sensitivity and specificity were 90% and 65%, respectively. Pretreatment plasma hepatocyte growth factor levels had no correlation with tissue immunoreactivities for hepatocyte growth factor, MET gene status and active EGFR mutations. Administration of epidermal growth factor receptor tyrosine kinase inhibitors significantly increased plasma hepatocyte growth factor levels. High levels of pretreatment plasma hepatocyte growth factor indicated intrinsic resistance to epidermal growth factor receptor tyrosine kinase inhibitors. Plasma hepatocyte growth factor can serve as a useful biomarker for the early diagnosis of tumor relapse treated with epidermal growth factor receptor tyrosine kinase inhibitors.

Repeated gene transfection impairs the engraftment of transplanted porcine neonatal pancreatic cells

BACKGROUND

Previously, we reported that neonatal porcine pancreatic cells transfected with hepatocyte growth factor (HGF) gene in an Epstein-Barr virus (EBV)-based plasmid (pEBVHGF) showed improved proliferation and differentiation compared to those of the control. In this study, we examined if pancreatic cells transfected repeatedly with pEBVHGF can be successfully grafted to control blood glucose in a diabetes mouse model.

METHODS

Neonatal porcine pancreatic cells were cultured as a monolayer and were transfected with pEBVHGF every other day for a total of three transfections. The transfected pancreatic cells were re-aggregated and transplanted into kidney capsules of diabetic nude mice or normal nude mice. Blood glucose level and body weight were measured every other day after transplantation. The engraftment of the transplanted cells and differentiation into beta cells were assessed using immunohistochemistry.

RESULTS

Re-aggregation of the pancreatic cells before transplantation improved engraftment of the cells and facilitated neovascularization of the graft. Right before transplantation, pancreatic cells that were transfected with pEBVHGF and then re-aggregated showed ductal cell marker expression. However, ductal cells disappeared and the cells underwent fibrosis in a diabetes mouse model two to five weeks after transplantation; these mice also did not show controlled blood glucose levels. Furthermore, pancreatic cells transplanted into nude mice with normal blood glucose showed poor graft survival regardless of the type of transfected plasmid (pCEP4, pHGF, or pEBVHGF).

CONCLUSION

For clinical application of transfected neonatal porcine pancreatic cells, further studies are required to develop methods of overcoming the damage for the cells caused by repeated transfection and to re-aggregate them into islet-like structures.

shRNA-mediated decreases in c-Met levels affect the differentiation potential of human mesenchymal stem cells and reduce their capacity for tissue repair

Mesenchymal stem cells/marrow stromal cells (MSC) are adult multipotent cells that can augment tissue repair. We previously demonstrated that culturing MSC in hypoxic conditions causes upregulation of the hepatocyte growth factor (HGF) receptor c-Met, allowing them to respond more robustly to HGF. MSC preconditioned in hypoxic environments contributed to restoration of blood flow after an ischemic injury more rapidly than MSC cultured in normoxic conditions. We now investigated the specific role of HGF/c-Met signaling in MSC function. An shRNA-mediated knockdown (KD) of c-Met in MSC did not alter their phenotypic profile, proliferation, or viability in vitro. However, we determined that while HGF/c-Met signaling does not play a role in the adipogenic differentiation of the cells, the disruption of this signaling pathway inhibited the ability of MSC to differentiate into the osteogenic and chondrogenic lineages. We next assessed the impact of c-Met KD on human MSC function in a xenogeneic hindlimb ischemia injury model. A 70% KD of c-Met in MSC resulted in a significant decrease in their capacity to regenerate blood flow to the ischemic limb, as compared to the MSC transduced with control shRNA. MSC with only a 60% KD of c-Met exhibited an intermediate capacity to restore blood flow, suggesting that MSC function is sensitive to the dosage of c-Met signaling. The current study highlights the significance of HGF/c-Met signaling in the capacity of MSC to restore blood flow after an ischemic injury and in their ability to differentiate into the osteogenic and chondrogenic lineages.

Hepatocyte growth factor twenty years on: Much more than a growth factor

Liver regeneration depends on the proliferation of mature hepatocytes. In the 1980s, the method for the cultivation of mature hepatocytes provided an opportunity for the discovery of hepatocyte growth factor (HGF) as a protein that is structurally and functionally different from other growth factors. In 1991, the scatter factor, tumor cytotoxic factor, and 3-D epithelial morphogen were identified as HGF, and Met tyrosine kinase was identified as the receptor for HGF. Thus, the connection of apparently unrelated research projects rapidly enriched the research on HGF in different fields. The HGF-Met pathway plays important roles in the embryonic development of the liver and the placenta, in the migration of myogenic precursor cells, and in epithelial morphogenesis. The use of tissue-specific knockout mice demonstrated that in mature tissues the HGF-Met pathway plays a critical role in tissue protection and regeneration, and in providing less susceptibility to chronic inflammation and fibrosis. In various injury and disease models, HGF promotes cell survival, regeneration of tissues, and suppresses and improves chronic inflammation and fibrosis. Drug development using HGF has been challenging, but extensive preclinical studies to address its therapeutic effects have provided significant results sufficient for the development of HGF as a biological drug in the regeneration-based therapy of diseases. Clinical trials using recombinant human HGF protein, or HGF genes, are in progress for the treatment of diseases.

Decreased Serum Hepatocyte Growth Factor (HGF) in Individuals with Schizophrenia Normalizes after Zinc and B-6 Therapy

Aim

To assess serum HGF concentration in individuals with schizophrenia and investigate the efficacy of zinc and B-6 therapy on these levels.

Subjects and methods

Serum from 18 individuals diagnosed with schizophrenia and 19 age and gender similar controls ( P = 0.18) were tested for HGF concentration using ELISAs, and tested for copper and zinc plasma levels using inductively-coupled plasma-mass spectrometry.

Results

HGF serum levels of individuals with schizophrenia, before zinc and B-6 therapy, were significantly lower than age and gender similar controls ( P = 0.016), and significantly lower in schizophrenia patients pre-therapy compared to post therapy ( P = 0.028). HGF levels normalized (reached levels similar to controls) post-therapy. Zinc levels in these same individuals also normalized, and perceived symptoms, particularly anxiety ( P = 0.03), improved significantly after therapy.

Discussion

These results suggest an association between low HGF levels and schizophrenia and demonstrate that zinc and B-6 therapy may be associated with the normalization of HGF levels and perceived improvement in symptoms.

Tumor-stroma interactions reduce the efficacy of adenoviral therapy through the HGF-MET pathway

Many preclinical studies have shown the potential of adenovirus-based cancer gene therapy. However, successful translation of these promising results into the clinic has not yet been achieved. Pancreatic ductal adenocarcinoma (PDAC) is characterized by abundant desmoplastic stroma, and tumor-stromal cell interactions play a critical role in tumor progression. Therefore, we hypothesized that tumor-stroma interactions reduce the efficacy of adenoviral therapy. We investigated the effect of fibroblasts on adenovirus-based gene therapy using SUIT-2 and PANC-1 pancreatic cancer cells cultured with or without fibroblast-conditioned culture supernatant then infected with Ad-LacZ. After 48 h, the cells were stained for β-galactosidase. The results showed that the number of β-galactosidase-positive cells was significantly reduced after culture with fibroblast-conditioned supernatant (P < 0.05). Because the hepatocyte growth factor (HGF)/MET pathway plays an important role in tumor-stroma interactions we next investigated the involvement of this pathway in tumor-stroma interactions leading to the decreased efficacy of adenoviral therapy. SUIT-2 cells were cultured with or without SU11274 (a MET inhibitor) and/or fibroblast-conditioned culture supernatant, then infected with Ad-GFP. After 48 h, GFP-positive cells were counted. The number of GFP-positive cells in cultures containing fibroblast-conditioned supernatant plus SU11274 was significantly greater than in cultures without SU11274. In conclusion, our results suggest that stromal cells in PDAC reduce the efficacy of adenoviral therapy through a mechanism involving the HGF/MET pathway. Control of such tumor-stroma interactions may lead to improvements in adenoviral gene therapy for PDAC.

Growth factor- and cytokine-driven pathways governing liver stemness and differentiation

Liver is unique in its capacity to regenerate in response to injury or tissue loss. Hepatocytes and other liver cells are able to proliferate and repopulate the liver. However, when this response is impaired, the contribution of hepatic progenitors becomes very relevant. Here, we present an update of recent studies on growth factors and cytokine-driven intracellular pathways that govern liver stem/progenitor cell expansion and differentiation, and the relevance of these signals in liver development, regeneration and carcinogenesis. Tyrosine kinase receptor signaling, in particular, c-Met, epidermal growth factor receptors or fibroblast growth factor receptors, contribute to proliferation, survival and differentiation of liver stem/progenitor cells. Different evidence suggests a dual role for the transforming growth factor (TGF)-β signaling pathway in liver stemness and differentiation. On the one hand, TGF-β mediates progression of differentiation from a progenitor stage, but on the other hand, it contributes to the expansion of liver stem cells. Hedgehog family ligands are necessary to promote hepatoblast proliferation but need to be shut off to permit subsequent hepatoblast differentiation. In the same line, the Wnt family and β-catenin/T-cell factor pathway is clearly involved in the maintenance of liver stemness phenotype, and its repression is necessary for liver differentiation during development. Collectively, data indicate that liver stem/progenitor cells follow their own rules and regulations. The same signals that are essential for their activation, expansion and differentiation are good candidates to contribute, under adequate conditions, to the paradigm of transformation from a pro-regenerative to a pro-tumorigenic role. From a clinical perspective, this is a fundamental issue for liver stem/progenitor cell-based therapies.

Antiapoptotic and antiautophagic effects of glial cell line-derived neurotrophic factor and hepatocyte growth factor after transient middle cerebral artery occlusion in rats

Glial cell line-derived neurotrophic factor (GDNF) and hepatocyte growth factor (HGF) are strong neurotrophic factors, which function as antiapoptotic factors. However, the neuroprotective effect of GDNF and HGF in ameliorating ischemic brain injury via an antiautophagic effect has not been examined. Therefore, we investigated GDNF and HGF for changes of infarct size and antiapoptotic and antiautophagic effects after transient middle cerebral artery occlusion (tMCAO) in rats. For the estimation of ischemic brain injury, the infarct size was calculated at 24 hr after tMCAO by HE staining. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick end labeling (TUNEL) was performed for evaluating the antiapoptotic effect. Western blot analysis of microtubule-associated protein 1 light chain 3 (LC3) and immunofluorescence analysis of LC3 and phosphorylated mTOR/Ser(2448) (p-mTOR) were performed for evaluating the antiautophagic effect. GDNF and HGF significantly reduced infarct size after cerebral ischemia. The amounts of LC3-I plus LC3-II (relative to beta-tubulin) were significantly increased after tMCAO, and GDNF and HGF significantly decreased them. GDNF and HGF significantly increased p-mTOR-positive cells. GDNF and HGF significantly decreased the numbers of TUNEL-, LC3-, and LC3/TUNEL double-positive cells. LC3/TUNEL double-positive cells accounted for about 34.3% of LC3 plus TUNEL-positive cells. This study suggests that the protective effects of GDNF and HGF were greatly associated with not only the antiapoptotic but also the antiautophagic effects; maybe two types of cell death can occur in the same cell at the same time, and GDNF and HGF are capable of ameliorating these two pathways.

Decreased Serum Hepatocyte Growth Factor (HGF) in Individuals with Bipolar Disorder Normalizes after Zinc and Anti-oxidant Therapy

Aim:

To assess serum HGF concentration in individuals with bipolar disorder and investigate the efficacy of zinc therapy on these levels.

Subjects and methods:

Serum from 35 individuals diagnosed with bipolar disorder and 19 age and gender similar controls were tested for HGF concentration using ELISAs, and copper and zinc plasma levels using inductively-coupled plasma-mass spectrometry.

Results:

HGF serum levels of individuals with bipolar disorder were significantly lower than age and gender similar controls (P = 0.0021). HGF serum concentration was significantly lower in Bipolar patients pre-therapy (P = 0.0009) and HGF levels normalized post-therapy. Zinc levels in these same individuals also normalized (P = 0.0046) and patient’s perceived severity of Bipolar symptoms significantly decreased after therapy (P = 0.0003). We also found a significant direct correlation between Zinc and HGF serum concentration in the bipolar patients (P = 0.04).

Discussion:

These results suggest an association between low HGF levels and bipolar disorder and also demonstrate that zinc therapy may be associated with the normalization of HGF levels and decrease in severity of disease.

Experimental approaches for the treatment of malignant gliomas

Malignant gliomas, which include glioblastomas and anaplastic astrocytomas, are the most common primary tumors of the brain. Over the past 30 years, the standard treatment for these tumors has evolved to include maximal safe surgical resection, radiation therapy and temozolomide chemotherapy. While the median survival of patients with glioblastomas has improved from 6 months to 14.6 months, these tumors continue to be lethal for the vast majority of patients. There has, however, been recent substantial progress in our mechanistic understanding of tumor development and growth. The translation of these genetic, epigenetic and biochemical findings into therapies that have been tested in clinical trials is the subject of this review.

Protective effects of HGF-MSP chimer (metron factor-1) on liver ischemia-reperfusion injury in rat model

OBJECTIVE

It has been reported that metron factor-1 (MF-1), an engineered chimerical factor containing selected functional domains of hepatocyte growth factor and macrophage-stimulating protein (HGF-MSP), could prevent apoptosis and have an anti-inflammatory effect. In this study, we investigate the protective effect of MF-1 on liver ischemia-reperfusion (I/R) injury.

METHODS

Overall 30 Sprague Dawley rats were randomly divided into three groups: the I/R model group (n=12), the MF-1 treatment group (n=12), and the sham-operated group (n=6). Liver I/R injury was induced by clamping the blood supply to the left and median lobes of liver by an atraumatic clamp for 90 min, then removing the clamp and allowing reperfusion. Blood samples were obtained on days 1, 2, 3 and 7 to assess liver biochemistry and the histology of liver tissue. Levels of malondialdehyde (MDA), superoxide dismutase (SOD), nitric oxide (NO), endothelial nitric oxide synthase and inducible nitric oxide synthase were measured. In addition, the anti-oxidative effect of MF-1 on hepatocytes was assessed in vitro.

RESULTS

MF-1 treatment improved the rat survival rate significantly (P < 0.05). Liver biochemistry and histological changes were significantly ameliorated. MDA increased and SOD and NO decreased in the liver tissue. In vitro, MF-1 protected the human hepatic cell line HL-7702 from damage of oxidative stress.

CONCLUSION

MF-1 could protect the liver from I/R injury, which might involve the reduction of oxygen free radicals and the increase of NO synthesis in an injured liver.

Inhibition of Met/HGF receptor and angiogenesis by NK4 leads to suppression of tumor growth and migration in malignant pleural mesothelioma

NK4 exhibits two distinct biological actions: antagonistic inhibition of hepatocyte growth factor (HGF) through binding to the Met/HGF receptor, and antiangiogenic action through binding to perlecan. Here, the anti-tumor effect of NK4 on malignant pleural mesothelioma was investigated. Of the 7 human malignant mesothelioma cell lines (ACC-Meso-1, ACC-Meso-4, EHMES-1, EHMES-10, H28, H2052 and JMN-1B), only EHMES-10 cells formed subcutaneous tumors when implanted into mice. For EHMES-10 cells, HGF facilitated invasion of the cells in collagen gel, whereas NK4 and neutralizing anti-HGF antibody suppressed the HGF-induced invasion. In addition, NK4 but not anti-HGF antibody suppressed proliferation of EHMES-10 cells in collagen, suggesting that the suppression by NK4 was independent of the HGF-Met pathway. In the subcutaneous tumor model, recombinant adenovirus-mediated intratumoral expression of NK4 inhibited tumor growth, while the invasive characteristic of tumor cells was not observed. Analysis of Met receptor tyrosine phosphorylation, proliferation, apoptosis and blood vessels in the tumor tissues indicated that the inhibitory effect of NK4 expression might be primarily caused by the inhibition of tumor angiogenesis. In all the 7 mesothelioma lines, HGF stimulated Met tyrosine phosphorylation, and this was associated with enhanced cell migration. HGF-dependent Met activation and migration were inhibited by NK4. Since malignant pleural mesothelioma represents an aggressive neoplasm characterized by extensive invasive growth, suppression of invasive growth has therapeutic value. Thus, the simultaneous inhibition of the HGF-Met pathway and angiogenesis by NK4 for treatment of malignant pleural mesothelioma is significant, particularly to attenuate migration and invasive growth.

Decreased Serum Hepatocyte Growth Factor (HGF) in Individuals with Anxiety Increases After Zinc Therapy

Aim:

To assess serum Hepatocyte Growth Factor (HGF) levels in individuals with anxiety and to test the hypothesis that there is a relationship between HGF levels and zinc therapy.

Subjects and methods:

Serum from 19 individuals with anxiety and 19 controls were tested for serum HGF using ELISAs. HGF serum concentration in individuals with anxiety before zinc and anti-oxidant therapy was compared to levels after therapy. Zinc and copper levels in anxiety patients, pre and post therapy, were also measured and compared.

Results:

Individuals with anxiety had significantly lower serum levels of HGF compared to controls (P = 0.0005). HGF concentration rose significantly (normalized) after zinc therapy (P = 0.04) and zinc levels increased significantly in these same patients (P = 0.0002).

Discussion:

These results suggest an association between HGF serum levels and individuals with anxiety and demonstrate that zinc therapy is associated with increasing HGF levels.

Decreased Serum Hepatocyte Growth Factor (HGF) in Individuals with Depression Correlates with Severity of Disease

AIM

To assess serum Hepatocyte Growth Factor (HGF) levels in individuals with depression and to test the hypothesis that there is a relationship between severity of depression and HGF concentration.

SUBJECTS AND METHODS

Serum from 26 clinically depressed individuals and 19 controls were tested for serum HGF using ELISAs. Correlation was established between HGF concentration and disease severity.

RESULTS

Depressed individuals had significantly lower serum levels of HGF compared to controls (P < 0.0001). HGF concentration correlated with overall depressive behavior (P = 0.03) and specifically depression (P = 0.02), but not anxiety (P = 0.36).

DISCUSSION

These results suggest an association between HGF serum levels and clinically depressed individuals and demonstrate a correlation between severity of depression and HGF levels. Further studies of the predictive strength of HGF as a biomarker for depression may be warranted.

Growth factor signaling pathways as targets for prevention of epithelial carcinogenesis

Growth factor receptor (GFR) signaling controls epithelial cell growth by responding to various endogenous or exogenous stimuli and subsequently activating downstream signaling pathways including Stat3, PI3K/Akt/mTOR, MAPK, and c-Src. Environmental chemical toxicants and UVB irradiation cause enhanced and prolonged activation of GFR signaling and downstream pathways that contributes to epithelial cancer development including skin cancer. Recent studies, especially those with tissue-specific transgenic mouse models, have demonstrated that GFRs and their downstream signaling pathways contribute to all three stages of epithelial carcinogenesis by regulating a wide variety of biological functions including proliferation, apoptosis, angiogenesis, cell adhesion, and migration. Inhibiting these signaling pathways early in the carcinogenic process results in reduced cell proliferation and survival, leading to decreased tumor formation. Collectively, these studies suggest that GFR signaling and subsequent downstream signaling pathways are potential targets for the prevention of epithelial cancers including skin cancer.

Effects of hepatocyte growth factor on differentiation and cMET receptor expression in the promyelocytic HL60 cell line

Aim-To determine the effects of hepatocyte growth factor (HGF) on myeloid cell differentiation and cMET expression using the promyelocytic HL60 cell line.Methods-HL60 cells cultured with purified recombinant HGF, dimethyl sulphoxide (DMSO), or 12-O tetradecanoylphorbol-13-acetate (TPA) were immunostained for the differentiation markers, human neutrophil elastase (HNE), cathepsin B, MAC387, or the receptor for hepatocyte growth factor (cMET).Results-HGF treated cells were positive on staining for cathepsin B and MAC387, but were negative for HNE, indicating monocytic differentiation. HGF treated cells had the morphology of monocytes but continued to divide at the same rate as control cells and remained non-adherent. DMSO treated cells were positive for HNE and cell numbers were reduced, confirming myeloid differentiation. TPA treated cells were positive for cathepsin B and MAC387, cell numbers were reduced, and the cells became adherent, confirming terminal monocytic differentiation. Untreated HL60 cells were weakly positive for cMET at the start of the culture period and expression increased after 72 hours. Cells treated with HGF, DMSO, or TPA were also positive for cMET.Conclusions-These data suggest that HGF induced partial monocytic differentiation in HL60 cells. In addition, expression of cMET by HL60 cells occurs at an early stage in myelomonocytic cells and is maintained after differentiation along either the myeloid or monocytic pathways.

The PI3K-Akt mediates oncogenic Met-induced centrosome amplification and chromosome instability

The oncogenic ability of aberrant hepatocyte growth factor receptor (Met) signaling is thought to mainly rely on its mitogenic and anti-apoptotic effects. Recently, however, cumulating evidences suggest that genomic instability may be a crucial factor in tumorigenesis. Here, we address whether oncogenic Met receptor is linked to the centrosome abnormality and genomic instability. We showed that expression of the constitutive active Met (CA-Met) induced supernumerary centrosomes probably due to deregulated centrosome duplication, which was accompanied with multipolar spindle formation and aneuploidy. Interestingly, LY294002, a phosphoinositide 3-kinase (PI3K) inhibitor, significantly suppressed the appearance of supernumerary centrosomes. Moreover, knockdown of Akt with small interfering RNAs and overexpression of phosphatase and tensin homolog or dominant-negative Akt abrogated supernumerary centrosome formation, evidencing the involvement of PI3K signaling. We further showed that expression of CA-Met significantly increased aneuploidy in p53(-/-) HCT116 cells, but not in p53(+/+) HCT116 cells, indicating that the ability of CA-Met to induce chromosomal instability (CIN) phenotype is related with p53 status. Together, our data demonstrate that aberrant hepatocyte growth factor/Met signaling induces centrosome amplification and CIN via the PI3K-Akt pathway, providing an example that oncogenic growth factor signals prevalent in a wide variety of cancers have cross talks to centrosome abnormality and CIN.

Neurotrophic growth factors for the treatment of amyotrophic lateral sclerosis: where do we stand?

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease that results in progressive loss of motoneurons, motor weakness and death within 3–5 years after disease onset. Therapeutic options remain limited despite substantial number of approaches that have been tested clinically. Many neurotrophic growth factors are known to promote the survival of neurons and foster regeneration in the central nervous system. Various neurotrophic factors have been investigated pre-clinically and clinically for the treatment of ALS. Although pre-clinical data appeared promising, no neurotrophic factors succeeded yet in a clinical phase III trial. In this review we discuss the rationale behind those factors, possible reasons for clinical failures, and argue for a renewal of hope in this powerful class of drugs for the treatment of ALS.

The heparin-binding domain of HB-EGF mediates localization to sites of cell-cell contact and prevents HB-EGF proteolytic release

Heparin-binding EGF-like growth factor (HB-EGF) is a ligand for EGF receptor (EGFR) and possesses the ability to signal in juxtacrine, autocrine and/or paracrine mode, with these alternatives being governed by the degree of proteolytic release of the ligand. Although the spatial range of diffusion of released HB-EGF is restricted by binding heparan-sulfate proteoglycans (HSPGs) in the extracellular matrix and/or cellular glycocalyx, ascertaining mechanisms governing non-released HB-EGF localization is also important for understanding its effects. We have employed a new method for independently tracking the localization of the extracellular EGF-like domain of HB-EGF and the cytoplasmic C-terminus. A striking observation was the absence of the HB-EGF transmembrane pro-form from the leading edge of COS-7 cells in a wound-closure assay; instead, this protein localized in regions of cell-cell contact. A battery of detailed experiments found that this localization derives from a trans interaction between extracellular HSPGs and the HB-EGF heparin-binding domain, and that disruption of this interaction leads to increased release of soluble ligand and a switch in cell phenotype from juxtacrine-induced growth inhibition to autocrine-induced proliferation. Our results indicate that extracellular HSPGs serve to sequester the transmembrane pro-form of HB-EGF at the point of cell-cell contact, and that this plays a role in governing the balance between juxtacrine versus autocrine and paracrine signaling.

Knockdown of stromal interaction molecule 1 attenuates hepatocyte growth factor-induced endothelial progenitor cell proliferation

Increased Ca(2+) entry through store-operated Ca(2+) channels (SOCCs) plays an essential role in the regulation of hepatocyte growth factor (HGF)-induced cell proliferation. Stromal interaction molecule 1 (STIM1) is thought to transmit endoplasmic reticulum (ER) Ca(2+) store depletion signals to the plasma membrane (PM), causing the opening of SOCCs in the PM. However, the relationship between HGF and STIM1 in endothelial progenitor cell (EPC) proliferation remains uncharacterized. The objective of this study was to evaluate the potential involvement of STIM1 in HGF-induced EPC proliferation. For this purpose, we used cultured rat bone marrow-derived EPCs and found that HGF-induced EPC proliferation at low concentrations. Store-operated Ca(2+) entry (SOCE) was elevated in HGF-treated EPCs, and the SOCC inhibitors 2-aminoethoxydiphenyl borate (2-APB) and BTP-2 inhibited the HGF-induced proliferation response. Moreover, STIM1 mRNA and protein expression levels were increased in response to HGF stimulation and knockdown of STMI1 decreased SOCE and prevented HGF-induced EPC proliferation. In conclusion, our data suggest that HGF-induced EPC proliferation is mediated partly via activation of STIM1.

Hepatocyte growth factor and the risk of ischemic stroke developing among postmenopausal women: results from the Women's Health Initiative

BACKGROUND AND PURPOSE

Hepatocyte growth factor (HGF) is a potent angiogenic factor and may play a role in the development and progression of atherosclerotic lesions, the underlying mechanism of cardiovascular disease. However, there have been no prospective studies examining the relationship between HGF levels and risk of stroke.

METHODS

We conducted a nested case-control study (972 incident stroke cases and 1:1 age-matched and race-matched controls) to prospectively evaluate the association between plasma HGF and risk of ischemic stroke within the Women's Health Initiative Observational Study, a cohort of postmenopausal women aged 50 to 79 years.

RESULTS

Baseline HGF levels were correlated positively with body mass index, systolic blood pressure, low-density lipoprotein cholesterol, insulin resistance, and inflammatory markers, such as C-reactive protein, and inversely with high-density lipoprotein cholesterol (all P<0.05). Baseline HGF levels were higher among cases than controls (geometric means, 601.8 vs 523.2 pg/mL; P=0.003). Furthermore, the risk of incident ischemic stroke was significantly greater among women in the highest vs lowest quartile of plasma HGF levels (OR, 1.46; 95% CI, 1.12-1.91; P(trend)=0.003) in a conditional logistic regression model that adjusted for body mass index. These results were only slightly attenuated after further adjustment for additional stroke risk factors (OR, 1.39; 95% CI, 1.04-1.85; P(trend)=0.023).

CONCLUSIONS

Circulating levels of HGF are associated with an increased risk of incident ischemic stroke, independent of obesity and other risk factors for cardiovascular disease, among postmenopausal women aged 50 to 79 years.

Hepatocyte growth factor--a new marker for prognosis in acute coronary syndrome

This study was designed to check the properties of hepatocyte growth factor (HGF) as a new marker of myocardial necrosis.

MATERIALS AND METHOD

In one hundred and four patients with acute coronary syndrome (ACS), plasma human HGF (hHGF) concentrations were assessed twice, i.e. just after admission to hospital and 24 h afterwards. The primary composite endpoint was assessed at three-month follow-up.

RESULTS

The maximal concentration of hHGF (1902 pg/ml) was reached at the time of admission to hospital due to ACS with significant decrease 24 h after the first measurement (705 pg/ml p < 0.0001). hHGF levels in ST segment elevation myocardial infarction (STEMI) were higher than in non-ST segment elevation myocardial infarction (NSTEMI) and in patients who reached composite primary endpoint (33 patients-4211 pg/ml) vs. event-free 71 patients (1013 pg/ml p < 0.01). The correlation between values of hHGF and N-terminal prohormone B-type natriuretic peptide and cardiac troponin I was revealed.

CONCLUSION

HGF is a very early, good marker of myocardial necrosis and a sensitive short- and long-term prognostic factor in ACS.

Hepatocyte growth factor inhibits CNS autoimmunity by inducing tolerogenic dendritic cells and CD25+Foxp3+ regulatory T cells

Immune-mediated diseases of the CNS, such as multiple sclerosis and its animal model, experimental autoimmune encephalitis (EAE), are characterized by the activation of antigen-presenting cells and the infiltration of autoreactive lymphocytes within the CNS, leading to demyelination, axonal damage, and neurological deficits. Hepatocyte growth factor (HGF) is a pleiotropic factor known for both neuronal and oligodendrocytic protective properties. Here, we assess the effect of a selective overexpression of HGF by neurons in the CNS of C57BL/6 mice carrying an HGF transgene (HGF-Tg mice). EAE induced either by immunization with myelin oligodendrocyte glycoprotein peptide or by adoptive transfer of T cells was inhibited in HGF-Tg mice. Notably, the level of inflammatory cells infiltrating the CNS decreased, except for CD25(+)Foxp3(+) regulatory T (T(reg)) cells, which increased. A strong T-helper cell type 2 cytokine bias was observed: IFN-gamma and IL-12p70 decreased in the spinal cord of HGF-Tg mice, whereas IL-4 and IL-10 increased. Antigen-specific response assays showed that HGF is a potent immunomodulatory factor that inhibits dendritic cell (DC) function along with differentiation of IL-10-producing T(reg) cells, a decrease in IL-17-producing T cells, and down-regulation of surface markers of T-cell activation. These effects were reversed fully when DC were pretreated with anti-cMet (HGF receptor) antibodies. Our results suggest that, by combining both potentially neuroprotective and immunomodulatory effects, HGF is a promising candidate for the development of new treatments for immune-mediated demyelinating diseases associated with neurodegeneration such as multiple sclerosis.

Hepatocyte growth factor receptor, c-Met, in human embryo salivary glands. An immunohistochemical study

Salivary gland morphogenesis involves complex, coordinated events that include epithelial-mesenchymal interactions. Mesenchymal-epithelial transition factor (c-Met) is the hepatocyte growth factor (HGF) receptor. The latter is a hepatotropic factor originally identified in rat serum and platelets. It is essential in fetal tissue development, where it regulates complex morphogenetic processes including extracellular matrix invasion, cell migration, cell polarization and tubulogenesis. The c-Met/HGF system is believed to participate in epithelial-mesenchymal interactions during development. Twelve human embryonic minor salivary glands were studied by immunohistochemistry to investigate the role of c-Met in human salivary gland development. Strong c-Met immunopositivity in the glands demonstrated that the molecule is involved in their development and suggested a role for the c-Met/HGF system in this process.

Induction of hepatocyte growth factor by fucoidan and fucoidan-derived oligosaccharides

Fucoidan, which is extracted from brown seaweed, is a complex sulphated polysaccharide that is mostly composed of l-fucose and sulphated ester groups. The structural and anionic characteristics of fucoidan are similar to those of heparin. Heparin stimulates production of hepatocyte growth factor (HGF), which has key roles in tissue regeneration. We have shown that fucoidan and fucoidan-derived oligosaccharides have similar ability to stimulate production of HGF as heparin and heparin-derived oligosaccharides. This induction of HGF by heparin or fucoidan and their oligosaccharide derivates occurs primarily at the level of translation, probably via the same mechanism. Fucoidan may thus be useful to protect tissues and organs from various injuries and diseases, via mechanisms involving HGF.

A comparative study of carotid atherosclerotic plaque microvessel density and angiogenic growth factor expression in symptomatic versus asymptomatic patients

OBJECTIVE

A challenge facing clinicians is identifying patients with asymptomatic carotid disease at risk of plaque instability. We hypothesise that locally released angiogenic growth factors contribute to plaque instability.

METHODS

Carotid endarterectomy specimens from eight symptomatic and eight asymptomatic patients were interrogated for microvessel density and angiogenic growth factor expression histologically using immunofluorescence, and biochemically using quantitative real-time polymerase chain reaction (q-RT-PCR). Bio-Plex suspension array was used to assess circulating biomarkers in venous blood from the same patients and six healthy age-matched controls.

RESULTS

Immunofluorescence demonstrated significantly greater neovessel density in symptomatic plaques (P=0.010) with elevated expression of hepatocyte growth factor (HGF) (P=0.001) and its receptor MET (P=0.011) than in asymptomatic plaques. The q-RT-PCR demonstrated up-regulation of Endoglin (CD105), HGF (P=0.001) and MET (P=0.011) in the plaques of symptomatic versus asymptomatic patients. Bio-Plex suspension array demonstrated elevated HGF (P=0.002) serum levels in symptomatic versus asymptomatic patients and healthy controls, and decreased platelet-derived growth factor (PDGF) (P=0.036) serum levels in symptomatic versus asymptomatic patients.

CONCLUSION

Plaque instability may be mediated by HGF-induced formation of new microvessels, and decreased vessel stability resulting from decreased PDGF. Suspension array technology has the potential to identify circulating biomarkers that correlate with plaque rupture risk.

Facilitated tendon-bone healing by local delivery of recombinant hepatocyte growth factor in rabbits

PURPOSE

This study was performed to evaluate the therapeutic effect of hepatocyte growth factor (HGF) on tendon-bone healing in a rabbit model.

METHODS

In adult rabbits the long digital extensor tendon was detached from the lateral femoral condyle, and the free end of the tendon was inserted into a tunnel drilled into the proximal tibial metaphysis. Cancellous bone obtained during drilling of the tibial hole was soaked in saline solution or solution containing 100-microg/mL human recombinant HGF and then transplanted into the bone tunnel. Junctional healing between the tendon and the bone was evaluated by histologic analysis and uniaxial load-to-failure testing at 2, 4, 6, 8, and 12 weeks after surgery.

RESULTS

In the saline solution-treated control group, Sharpey-like fibers, which connected the tendon graft and the bone tissue, appeared 6 weeks after treatment. At 8 weeks after treatment, maturation of lamellar bone was seen, and at 12 weeks, the adhesion between tendon and bone appeared to be supported by indirect insertion of fibrocartilaginous tissue, wherein the border between the fibrocartilaginous tissue and tendon or bone was significant. In the HGF-treated group, the fibrous tissues were parallel to the load axis, and lamellar bone and Sharpey-like fibers appeared as early as 4 weeks after treatment. At 12 weeks, junctional tissue, characterized by a continuous 4-layer structure of bone, calcified cartilage, fibrocartilage, and tendon, was regenerated by a direct insertion. On biomechanical testing, the HGF-treated group had significantly better biomechanical properties than the control group at 2 and 4 weeks. The histologic improvement caused by HGF treatment was associated with the biomechanical improvement.

CONCLUSIONS

Local administration of recombinant HGF promotes the adhesive healing process at the tendon-bone junction, both histologically and mechanically, after ligament reconstruction in a rabbit model.

CLINICAL RELEVANCE

Application of HGF may be considered as a new therapeutic approach to accelerate healing and rehabilitation after ligament reconstruction.

The discovery of hepatocyte growth factor (HGF) and its significance for cell biology, life sciences and clinical medicine

It has been more than 25 years since HGF was discovered as a mitogen of hepatocytes. HGF is produced by stromal cells, and stimulates epithelial cell proliferation, motility, morphogenesis and angiogenesis in various organs via tyrosine phosphorylation of its receptor, c-Met. In fetal stages, HGF-neutralization, or c-Met gene destruction, leads to hypoplasia of many organs, indicating that HGF signals are essential for organ development. Endogenous HGF is required for self-repair of injured livers, kidneys, lungs and so on. In addition, HGF exerts protective effects on epithelial and non-epithelial organs (including the heart and brain) via anti-apoptotic and anti-inflammatory signals. During organ diseases, plasma HGF levels significantly increased, while anti-HGF antibody infusion accelerated tissue destruction in rodents. Thus, endogenous HGF is required for minimization of diseases, while insufficient production of HGF leads to organ failure. This is the reason why HGF supplementation produces therapeutic outcomes under pathological conditions. Moreover, emerging studies delineated key roles of HGF during tumor metastasis, while HGF-antagonism leads to anti-tumor outcomes. Taken together, HGF-based molecules, including HGF-variants, HGF-fragments and c-Met-binders are available as regenerative or anti-tumor drugs. Molecular analysis of the HGF-c-Met system could provide bridges between basic biology and clinical medicine.

Decreased Serum Hepatocyte Growth Factor (HGF) in Autistic Children with Severe Gastrointestinal Disease

Aim:

To assess serum Hepatocyte Growth Factor (HGF) levels in autistic children with severe gastrointestinal (GI) disease and to test the hypothesis that there is a relationship between GI pathology and HGF concentration.

Subjects and Methods:

Serum from 29 autistic children with chronic digestive disease (symptoms for a minimum of 6–12 months), most with ileo-colonic lymphoid nodular hyperplasia (LNH—markedly enlarged lymphoid nodules) and inflammation of the colorectum, small bowel and/or stomach), and 31 controls (11 age matched autistic children with no GI disease, 11 age matched non autistic children without GI disease and 9 age matched non autistic children with GI disease) were tested for HGF using ELISAs. HGF concentration of autistic children with GI disease was compared to GI disease severity.

Results:

Autistic children with GI disease had significantly lower serum levels of HGF compared to controls (autistic without GI disease; p = 0.0005, non autistic with no GI disease; p = 0.0001, and non autistic with GI disease; p = 0.001). Collectively, all autistic children had significantly lower HGF levels when compared to non autistic children (p < 0.0001). We did not find any relationship between severity of GI disease and HGF concentration in autistic children with GI disease.

Discussion:

These results suggest an association between HGF serum levels and the presence of GI disease in autistic children and explain a potential functional connection between the Met gene and autism. The concentration of serum HGF may be a useful biomarker for autistic children, especially those with severe GI disease.

The effect of timing in the administration of hepatocyte growth factor to modulate BMP-2-induced osteoblast differentiation

Development of bone morphogenetic protein (BMP) signaling modulators may provide useful therapeutic options for the treatment of large bony defects in clinical settings. Controversy remains over whether hepatocyte growth factor (HGF) is a positive or negative modulator of BMP-induced osteogenesis. This study analyzed osteogenic properties of HGF, particularly during BMP-2-induced bone formation. Using a mouse model of ectopic bone formation, HGF-impregnated gelatin sponges displayed significantly reduced bone formation induced by BMP-2, both radiologically and histologically. Abrogation of endogenous HGF production by knockdown of HGF mRNA resulted in upregulation of BMP-2-induced ALP activity for C2C12 myoblasts in vitro. In contrast, addition of exogenous HGF inhibited BMP-2-induced ALP activity and osteocalcin production by mouse embryonic fibroblasts (MEFs) through HGF-c-Met interactions. Inhibition of ALP activity by HGF was rescued by U0126, a MEK1/2 inhibitor, indicating that HGF suppresses the BMP-2-Smad axis via activation of ERK1/2. Importantly, treatment with HGF prior to administration of BMP-2 induced cellular proliferation of MEFs and did not influence subsequent osteoblast differentiation induced by BMP-2. The effects of HGF may differ according to the differentiation stage of mesenchymal stem cells, which would explain the inconsistencies seen in osteogenic properties of HGF in previous reports. The timing of HGF treatment is critical and should be carefully determined for successful induction of bone formation by BMPs.

Overproduction of recombinant human hepatocyte growth factor in Chinese hamster ovary cells

Hepatocyte growth factor (HGF) is a potent multi-functional protein that affects morphogenesis, cell migration, organ regeneration, and tumor invasion in various tissues, and has thus been considered to have potential as a therapeutic target in various diseases. In our current study, we established Chinese hamster ovary (CHO) cells overexpressing recombinant human HGF (rhHGF) protein and in a 5 day batch culture process using a 7.5l bioreactor (5l working volume) and serum-free medium these cells could produce over 13 mg/l of rhHGF protein. The recombinant protein was then purified to homogeneity from the culture supernatant using a two-step chromatographic procedure that resulted in about a 35% recovery rate. This purified rhHGF was found to be a mixture of inactive pro-HGF and an active heterodimeric form of this protein with a higher molecular weight than its counterpart expressed from insect cells. This finding suggests that the glycosylation of rhHGF protein in CHO cells differs from that in insect cells. Inactive pro-HGF was found to rapidly convert to the active heterodimeric form of HGF in the presence of FBS (Fetal Bovine Serum), suggesting that this process would occur also when injected into human body. We further demonstrate in cell proliferation and scattering activity assays that our purified rhHGF protein preparation is functionally active with a half-maximal effective concentration of 36.3 ng/ml.

Endogenous hepatocyte growth factor is a niche signal for subventricular zone neural stem cell amplification and self-renewal

Neural stem cells persist in the adult mammalian brain, within the subventricular zone (SVZ). The endogenous mechanisms underpinning SVZ neural stem cell proliferation, self-renewal, and differentiation are not fully elucidated. In the present report, we describe a growth-stimulatory activity of liver explant-conditioned media on SVZ cell cultures and identify hepatocyte growth factor (HGF) as a major player in this effect. HGF exhibited a mitogenic activity on SVZ cell cultures in a mitogen-activated protein kinase (MAPK) (ERK1/2)-dependent manner as U0126, a specific MAPK inhibitor, blocked it. Combining a functional neurosphere forming assay with immunostaining for c-Met, along with markers of SVZ cells subtypes, demonstrated that HGF promotes the expansion of neural stem-like cells that form neurospheres and self-renew. Immunostaining, HGF enzyme-linked immunosorbent assay and Madin-Darby canine kidney cell scattering assay indicated that SVZ cell cultures produce and release HGF. SVZ cell-conditioned media induced proliferation on SVZ cell cultures, which was blocked by HGF-neutralizing antibodies, hence implying that endogenously produced HGF accounts for a major part in SVZ mitogenic activity. Brain sections immunostaining revealed that HGF is produced by nestin-expressing cells and c-Met is expressed within the SVZ by immature cells. HGF intracerebroventricular injection promoted SVZ cell proliferation and increased the ability of these cells exposed in vivo to HGF to form neurospheres in vitro, whereas intracerebroventricular injection of HGF-neutralizing antibodies decreased SVZ cell proliferation. The present study unravels a major role, both in vitro and in vivo, for endogenous HGF in SVZ neural stem cell growth and self-renewal.

MCP-1 antibody treatment enhances damage and impedes repair of the alveolar epithelium in influenza pneumonitis

Recent studies have demonstrated an essential role of alveolar macrophages during influenza virus infection. Enhanced mortalities were observed in macrophage-depleted mice and pigs after influenza virus infection, but the basis for the enhanced pathogenesis is unclear. This study revealed that blocking macrophage recruitment into the lungs in a mouse model of influenza pneumonitis resulted in enhanced alveolar epithelial damage and apoptosis, as evaluated by histopathology, immunohistochemistry, Western blot, RT-PCR, and TUNEL assays. Abrogation of macrophage recruitment was achieved by treatment with monoclonal antibody against monocyte chemoattractant protein-1 (MCP-1) after sub-lethal challenge with mouse-adapted human influenza A/Aichi/2/68 virus. Interestingly, elevated levels of hepatocyte growth factor (HGF), a mitogen for alveolar epithelium, were detected in bronchoalveolar lavage samples and in lung homogenates of control untreated and nonimmune immunoglobulin (Ig)G-treated mice after infection compared with anti-MCP-1-treated infected mice. The lungs of control animals also displayed strongly positive HGF staining in alveolar macrophages as well as alveolar epithelial cell hyperplasia. Co-culture of influenza virus-infected alveolar epithelial cells with freshly isolated alveolar macrophages induced HGF production and phagocytic activity of macrophages. Recombinant HGF added to mouse lung explants after influenza virus infection resulted in enhanced BrdU labeling of alveolar type II epithelial cells, indicating their proliferation, in contrast with anti-HGF treatment showing significantly reduced epithelial regeneration. Our data indicate that inhibition of macrophage recruitment augmented alveolar epithelial damage and apoptosis during influenza pneumonitis, and that HGF produced by macrophages in response to influenza participates in the resolution of alveolar epithelium.