Ameliorating effect of hepatocyte growth factor on inflammatory bowel disease in a murine model

Experimental and Clinical Evidence of Endothelial Dysfunction in Inflammatory Bowel Disease

The endothelium has a crucial role in proper hemodynamics. Inflammatory bowel disease (IBD) is mainly a chronic inflammatory condition of the gastrointestinal tract. However, considerable evidence points to high cardiovascular risk in patients with IBD. This review positions the basic mechanisms of endothelial dysfunction in the IBD setting (both clinical and experimental). Furthermore, we review the main effects of drugs used to treat IBD in endothelial (dys)function. Moreover, we leave challenging points for enlarging the therapeutic arsenal for IBD with new or repurposed drugs that target endothelial dysfunction besides inflammation.

Clinical Significance of Hepatocyte Growth Factor and Transforming Growth Factor-Beta-1 Levels in Assessing Disease Activity in Inflammatory Bowel Disease

Background. Transforming growth factor-beta (TGF-β) and hepatocyte growth factor (HGF) are inflammatory cytokines which function as key regulators of immunological homeostasis and inflammatory responses. They have been linked to inflammatory bowel diseases (IBD). In this study, we aim to assess the levels of TGF-β and HGF and other inflammatory markers in patients with IBD and correlate them with the disease activity. Study Design. A cross-sectional study involving 100 patients with ulcerative colitis (UC) and 100 patients with Crohn's disease (CD) and 50 control subjects. TGF-β and HGF levels were measured and correlated with disease activity. Results and Conclusion. Serum levels of TGF-β and HGF were significantly higher in IBD patients compared with the control group. In the UC group, the levels of HGF and TGF-β were significantly higher than in the CD group. Levels of TGF-β and HGF correlate with the activity of IBD.

Mesenchymal Stromal Cells Modulate Corneal Alloimmunity via Secretion of Hepatocyte Growth Factor

Mesenchymal stromal cells (MSCs) are multipotent stem cells that participate in tissue repair and possess considerable immunomodulatory potential. MSCs have been shown to promote allograft survival, yet the mechanisms behind this phenomenon have not been fully defined. Here, we investigate the capacity of MSCs to suppress the allogeneic immune response by secreting the pleiotropic molecule hepatocyte growth factor (HGF). Using an in vivo mouse model of corneal transplantation, we report that MSCs promote graft survival in an HGF‐dependent manner. Moreover, our data indicate that topically administered recombinant HGF (a) suppresses antigen‐presenting cell maturation in draining lymphoid tissue, (b) limits T‐helper type‐1 cell generation, (c) decreases inflammatory cell infiltration into grafted tissue, and (d) is itself sufficient to promote transplant survival. These findings have potential translational implications for the development of HGF‐based therapeutics. stem cells translational medicine2019;8:1030–1040

Anti-inflammatory activities of hepatocyte growth factor in post-ischemic heart failure

Hepatocyte growth factor (HGF) alleviates acute and chronic inflammation in experimental inflammatory bowel disease, glomerulonephritis, and airway inflammation. However, the anti-inflammatory effects of HGF on myocardial infarction are not defined. The current study assessed the anti-inflammatory effects of HGF in post-ischemic heart failure. The left anterior descending coronary artery was ligated in rats, and adenovirus containing human HGF (Ad-HGF) or control virus (Ad-GFP) was administered intramyocardially. The quantity of proinflammatory cytokines secreted by cardiomyocytes, such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1β, was evaluated. Cardiac function and LV remodeling were assessed using echocardiography and collagen deposition, respectively. Left ventricular fractional shortening (LVFS) and left ventricular ejection fraction (LVEF) four weeks after injection were significantly increased in Ad-HGF-treated animals compared to the Ad-GFP group. HGF gene therapy improved ventricular geometry with a significantly decreased left ventricular end-diastolic diameter (LVEDD) and markedly reduced myocardial collagen deposition. Treatment with Ad-HGF significantly decreased the mRNA levels of TNF-α, IL-6, and IL-1β in the non-infarcted region four weeks after injection. Changes of the TNF-α, IL-6, and IL-1β levels in the non-infarcted region positively correlated with the LVEDD 4 weeks after infarction. Treatment of acute myocardial infarction (AMI) with Ad-HGF in the early stage of MI reduced the pro-inflammatory cytokine levels and preserved cardiac function. These findings indicated that Ad-HGF gene therapy alleviated ventricular remodeling after infarction by reducing inflammation.

The Impact of the Epithelial-Mesenchymal Transition Regulator Hepatocyte Growth Factor Receptor/Met on Skin Immunity by Modulating Langerhans Cell Migration

Langerhans cells (LCs), the epidermal dendritic cell (DC) subset, express the transmembrane tyrosine kinase receptor Met also known as hepatocyte growth factor (HGF) receptor. HGF is the exclusive ligand of Met and upon binding executes mitogenic, morphogenic, and motogenic activities to various cells. HGF exerts anti-inflammatory activities via Met signaling and was found to regulate various functions of immune cells, including differentiation and maturation, cytokine production, cellular migration and adhesion, and T cell effector function. It has only recently become evident that a number of HGF-regulated functions in inflammatory processes and immune responses are imparted via DCs. However, the mechanisms by which Met signaling in DCs conveys its immunoregulatory effects have not yet been fully understood. In this review, we focus on the current knowledge of Met signaling in DCs with particular attention on the morphogenic and motogenic activities. Met signaling was shown to promote DC mobility by regulating matrix metalloproteinase activities and adhesion. This is a striking resemblance to the role of Met in regulating a cell fate program during embryonic development, wound healing, and in tumor invasion known as epithelial–mesenchymal transition (EMT). Hence, we propose the concept that an EMT program is executed by Met signaling in LCs.

Hepatocyte growth factor (HGF) optimizes oral traumatic ulcer healing of mice by reducing inflammation

OBJECTIVE

To evaluate the influence of overexpression HGF on the healing of traumatic ulcer of oral mucosa of mice.

MATERIAL AND METHODS

Mice were divided into two groups: wild type C57BL6(WT) and HGF high expression transgenic (HGF-Tg) mice. Traumatic ulcer of all mice were made by number 15 scalpel blade. Mice were sacrificed after 5days and the inflammation score and expression of TNFα, IFNγ, c-Met, apoptosis (TUNEL) and 40 serum inflammation cytokines were estimated.

RESULTS

HGF-Tg mice presented a lower inflammation score (p=0.011), Serum TNFα expression in HGF-Tg ulcers is 1.3 times than WT ulcer and the difference is statistical significance (t test, p=0.003). Serum c-Met protein in HGF-Tg mice were significantly higher than WT mice (t test, p=0.004). No statistical difference was observed in the serum IFNγ between WT ulcer and HGF-Tg ulcer (t test, p=0.268). TNFα positive cytoplasm expression cells in connective tissue of HGF-Tg mice is significantly lower than that of WT group (t test, p=0.029). C-Met positive cytoplasm expression cells in both epithelium and connective tissue of HGF-Tg group is significantly higher than that of WT group (t test, p=0.040, p=0.000). Samples in HGF-Tg group showed a lower number of positive cells of epithelium TUNEL staining compared with that in the WT group (t test, p=0.035).

CONCLUSIONS

HGF exhibited anti-inflammatory potential in oral traumatic ulcer through the reduction of epithelial apoptosis, connective tissue TNFα expression and induction of c-Met expression.

Hepatocyte growth factor, hepatocyte growth factor activator and arginine in a rat fulminant colitis model

Introduction

Dextran sodium sulfate (DSS) is commonly used to induce a murine fulminant colitis model. Hepatocyte growth factor (HGF) has been shown to decrease the symptoms of inflammatory bowel disease (IBD) but the effect of its activator, HGFA, is not well characterized. Arginine reduces effects of oxidative stress but its effect on IBD is not well known. The primary aim is to determine whether HGF and HGFA, or arginine will decrease IBD symptoms such as pain and diarrhea in a DSS-induced fulminant colitis murine model.

Methods

A severe colitis was induced in young, male Fischer 344 rats with 4% (w/v) DSS oral solution for seven days; rats were sacrificed on day 10. Rats were divided into five groups of 8 animals: control, HGF (700 mcg/kg/dose), HGF and HGFA (10 mcg/dose), HGF and arginine, and high dose HGF (2800 mcg/kg/dose). Main clinical outcomes were pain, diarrhea and weight loss. Blinded pathologists scored the terminal ileum and distal colon.

Results

DSS reliably induced severe active colitis in 90% of animals (n = 36/40). There were no differences in injury scores between control and treatment animals. HGF led to 1.38 fewer days in pain (p = 0.036), while arginine led to 1.88 fewer days of diarrhea (P = 0.017) compared to controls. 88% of HGFA-treated rats started regaining weight (P < 0.001).

Discussion/Conclusion

Although treatment was unable to reverse fulminant disease, HGF and arginine were associated with decreased days of pain and diarrhea. These clinical interventions may reduce associated symptoms for severe IBD patients, even when urgent surgical intervention remains the only viable option.

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We developed a fulminant colitis model in adolescent rats.

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The fulminant colitis model reproduces inflammatory bowel disease in humans.

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The rats were treated with hepatocyte growth factor, its activator, and arginine.

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The HGF treated rats had fewer days of pain.

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The arginine treated rats had fewer days of diarrhea.

Preclinical and clinical evaluation of MET functions in cancer cells and in the tumor stroma

A lot of attention has been dedicated to investigate the role of the tyrosine kinase receptor MET in tumors. The acquired notion that cancer cells from different histological origin strictly rely on the engagement of this specific oncogene for their growth and survival has certainly justified the development and the use of MET-targeted therapies in the clinic. However, the function and involvement of this pathway in the stroma (that often constitutes >50% of the global cellularity of the tumor) may offer the opportunity to conceive new patient stratification criteria, rational drug design and guided trials of new combination treatments. In this review, we will summarize and discuss the role of MET in cancer cells but especially in different stromal compartments, in light of the results showed by past and recent preclinical and clinical trials with anti-MET drugs.

Angiogenesis in Inflammatory Bowel Disease

Angiogenesis is an important component of pathogenesis of inflammatory bowel disease (IBD). Chronic inflammation and angiogenesis are two closely related processes. Chronic intestinal inflammation is dependent on angiogenesis and this angiogenesis is modulated by immune system in IBD. Angiogenesis is a very complex process which includes multiple cell types, growth factors, cytokines, adhesion molecules, and signal transduction. Lymphangiogenesis is a new research area in the pathogenesis of IBD. While angiogenesis supports inflammation via leukocyte migration, carrying oxygen and nutrients, on the other hand, it has a major role in wound healing. Angiogenic molecules look like perfect targets for the treatment of IBD, but they have risk for serious side effects because of their nature.

Hepatocyte Growth Factor and MET Support Mouse Enteric Nervous System Development, the Peristaltic Response, and Intestinal Epithelial Proliferation in Response to Injury

Factors providing trophic support to diverse enteric neuron subtypes remain poorly understood. We tested the hypothesis that hepatocyte growth factor (HGF) and the HGF receptor MET might support some types of enteric neurons. HGF and MET are expressed in fetal and adult enteric nervous system. In vitro, HGF increased enteric neuron differentiation and neurite length, but only if vanishingly small amounts (1 pg/ml) of glial cell line-derived neurotrophic factor were included in culture media. HGF effects were blocked by phosphatidylinositol-3 kinase inhibitor and by MET-blocking antibody. Both of these inhibitors and MEK inhibition reduced neurite length. In adult mice, MET was restricted to a subset of calcitonin gene-related peptide-immunoreactive (IR) myenteric plexus neurons thought to be intrinsic primary afferent neurons (IPANs). Conditional MET kinase domain inactivation (Met(fl/fl); Wnt1Cre+) caused a dramatic loss of myenteric plexus MET-IR neurites and 1-1'-dioctodecyl-3,3,3',3'-tetramethylindocarbocyamine perchlorate (DiI) labeling suggested reduced MET-IR neurite length. In vitro, Met(fl/fl); Wnt1Cre+ mouse bowel had markedly reduced peristalsis in response to mucosal deformation, but normal response to radial muscle stretch. However, whole-bowel transit, small-bowel transit, and colonic-bead expulsion were normal in Met(fl/fl); Wnt1Cre+ mice. Finally, Met(fl/fl); Wnt1Cre+ mice had more bowel injury and reduced epithelial cell proliferation compared with WT animals after dextran sodium sulfate treatment. These results suggest that HGF/MET signaling is important for development and function of a subset IPANs and that these cells regulate intestinal motility and epithelial cell proliferation in response to bowel injury.

SIGNIFICANCE STATEMENT

The enteric nervous system has many neuronal subtypes that coordinate and control intestinal activity. Trophic factors that support these neuron types and enhance neurite growth after fetal development are not well understood. We show that a subset of adult calcitonin gene-related peptide (CGRP)-expressing myenteric neurons produce MET, the receptor for hepatocyte growth factor, and that loss of MET activity affects peristalsis in response to mucosal stroking, reduces MET-immunoreactive neurites, and increases susceptibility to dextran sodium sulfate-induced bowel injury. These observations may be relevant for understanding and treating intestinal motility disorders and also suggest that enhancing the activity of MET-expressing CGRP neurons might be a useful strategy to reduce bowel inflammation.

Immune mediators in the brain and peripheral tissues in autism spectrum disorder

Increasing evidence points to a central role for immune dysregulation in autism spectrum disorder (ASD). Several ASD risk genes encode components of the immune system and many maternal immune system-related risk factors--including autoimmunity, infection and fetal reactive antibodies--are associated with ASD. In addition, there is evidence of ongoing immune dysregulation in individuals with ASD and in animal models of this disorder. Recently, several molecular signalling pathways--including pathways downstream of cytokines, the receptor MET, major histocompatibility complex class I molecules, microglia and complement factors--have been identified that link immune activation to ASD phenotypes. Together, these findings indicate that the immune system is a point of convergence for multiple ASD-related genetic and environmental risk factors.

Hepatocyte growth factor: A regulator of inflammation and autoimmunity

Hepatocyte growth factor (HGF) is a pleiotropic cytokine that has been extensively studied over several decades, but was only recently recognized as a key player in mediating protection of many types of inflammatory and autoimmune diseases. HGF was reported to prevent and attenuate disease progression by influencing multiple pathophysiological processes involved in inflammatory and immune response, including cell migration, maturation, cytokine production, antigen presentation, and T cell effector function. In this review, we discuss the actions and mechanisms of HGF in inflammation and immunity and the therapeutic potential of this factor for the treatment of inflammatory and autoimmune diseases.

Intramuscular injection of adenoviral hepatocyte growth factor at a distal site ameliorates dextran sodium sulfate-induced colitis in mice

Inflammatory bowel disease (IBD) severely affects the quality of life of patients. At present, there is no clinical solution for this condition; therefore, there is a need for innovative therapies for IBD. Hepatocyte growth factor (HGF) exerts various biological activities in various organs. However, a clinically applicable and effective HGF-based therapy for IBD has yet to be developed. In this study, we examined the therapeutic effect of injecting an adenoviral vector encoding the human HGF gene (Ad.HGF) into the hindlimbs of mice with dextran sodium sulfate (DSS)-induced colitis. Plasma levels of circulating human HGF (hHGF) were measured in injected mice. The results showed that weight loss and colon shortening were significantly lower in Ad.HGF-infected mice as compared to control (Ad.LacZ-infected) colitic mice. Additionally, inflammation and crypt scores were significantly reduced in the entire length of the colon, particularly in the distal section. This therapeutic effect was associated with increased cell proliferation and an antiapoptotic effect, as well as a reduction in the number of CD4+ cells and a decreased CD4/CD8 ratio. The levels of inflammatory, as well as Th1 and Th2 cytokines were higher in Ad.HGF-infected mice as compared to the control colitic mice. Thus, systemically circulating hHGF protein, produced by an adenovirally transduced hHGF gene introduced at distal sites in the limbs, significantly ameliorated DSS-induced colitis by promoting cell proliferation (i.e., regeneration), preventing apoptosis, and immunomodulation. Owing to its clinical feasibility and potent therapeutic effects, this method may be developed into a clinical therapy for treating IBD.

Anti-VEGF therapy reduces intestinal inflammation in Endoglin heterozygous mice subjected to experimental colitis

Chronic intestinal inflammation is associated with pathological angiogenesis that further amplifies the inflammatory response. Vascular endothelial growth factor (VEGF), is a major angiogenic cytokine that has been implicated in chronic colitis and inflammatory bowel diseases. Endoglin (CD105), a transforming growth factor-β superfamily co-receptor expressed on endothelial and some myeloid cells, is a modulator of angiogenesis involved in wound healing and potentially in resolution of inflammation. We showed previously that Endoglin heterozygous (Eng (+/-)) mice subjected to dextran sodium sulfate developed severe colitis, abnormal colonic vessels and high tissue VEGF. We therefore tested in the current study if treatment with a monoclonal antibody to VEGF could ameliorate chronic colitis in Eng (+/-) mice. Tissue inflammation and microvessel density (MVD) were quantified on histological slides. Colonic wall thickness, microvascular hemodynamics and targeted MAdCAM-1(+) inflamed vessels were assessed in vivo by ultrasound. Mediators of angiogenesis and inflammation were measured by Milliplex and ELISA assays. Colitic Eng (+/-) mice showed an increase in intestinal inflammation, MVD, colonic wall thickness, microvascular hemodynamics and the number of MAdCAM-1(+) microvessels relative to colitic Eng (+/+) mice; these parameters were all attenuated by anti-VEGF treatment. Of all factors up-regulated in the inflamed gut, granulocyte colony-stimulating factor (G-CSF) and amphiregulin were further increased in colitic Eng (+/-) versus Eng (+/+) mice. Anti-VEGF therapy decreased tissue VEGF and inflammation-induced endoglin, IL-1β and G-CSF in colitic Eng (+/-) mice. Our results suggest that endoglin modulates intestinal angiogenic and inflammatory responses in colitis. Furthermore, contrast-enhanced ultrasound provides an excellent non-invasive imaging modality to monitor gut angiogenesis, inflammation and responses to anti-angiogenic treatment.

In vivo genetic engineering of murine pancreatic beta cells mediated by single-stranded adeno-associated viral vectors of serotypes 6, 8 and 9

AIMS/HYPOTHESIS

The genetic engineering of pancreatic beta cells could be a powerful tool for examining the role of key genes in the cause and treatment of diabetes. Here we performed a comparative study of the ability of single-stranded (ss) adeno-associated viral vectors (AAV) of serotypes 6, 8 and 9 to transduce the pancreas in vivo.

METHODS

AAV6, AAV8 and AAV9 vectors encoding marker genes were delivered to the pancreas via intraductal or systemic administration. Transduced cells were analysed by immunostaining. AAV9 vectors encoding hepatocyte growth factor (HGF) were delivered intraductally to a transgenic mouse model of type 1 diabetes and glycaemia was monitored.

RESULTS

AAV6, AAV8 and AAV9 mediated efficient and long-term transduction of beta cells, with AAV6 and AAV8 showing the highest efficiency. However, alpha cells were poorly transduced. Acinar cells were transduced by the three serotypes tested and ductal cells only by AAV6. In addition, intraductal delivery resulted in higher AAV-mediated transduction of the pancreas than did systemic administration. As proof of concept, intraductal delivery of AAV9 vectors encoding for the beta cell anti-apoptotic and mitogenic HGF preserved beta cell mass, diminished lymphocytic infiltration of the islets and protected mice from autoimmune diabetes.

CONCLUSIONS/INTERPRETATION

Intraductal administration of AAV6, AAV8 and AAV9 is an efficient way to genetically manipulate the pancreas in vivo. This technology may prove useful in the study of islet physiopathology and in assessment of new gene therapy approaches designed to regenerate beta cell mass during diabetes.

The protective role of host Toll-like receptor-4 in acute graft-versus-host disease

BACKGROUND

Mutations in Toll-like receptor (TLR)-4 have been associated with the hyporesponsiveness of macrophages to lipopolysaccharide, possibly reducing the risk of acute graft-versus-host disease (GVHD). However, TLR-4 mutations may also increase the risk of intestinal damage and microbial infection, thereby accelerating acute GVHD.

METHODS

In this study, we investigated the role of TLR-4 in triggering acute GVHD using C3H/HeJ mice with disrupted TLR-4 and C3H/HeN mice with intact TLR-4 as recipients in an acute GVHD model.

RESULTS

TLR-4 expression was significantly increased in the intestines and livers from acute GVHD mice. TLR-4-mutant C3H/HeJ hosts that received C57BL/6 (B6) donor cells developed significantly more severe GVHD than TLR-4-intact C3H/HeN hosts receiving B6 donor cells. Antibiotic treatment prolonged the survival of C3H/HeN-host GVHD mice but reduced the survival of C3H/HeJ-host GVHD mice. C3H/HeJ-host GVHD mice showed increased lipopolysaccharide levels in the blood, donor cell and CD68+ cell infiltration, tumor necrosis factor-α mRNA expression, and more apoptotic cells in the intestine compared with C3H/HeN host GVHD mice. In contrast, intestinal cyclooxygenase-2, prostaglandin E2, and hepatocyte growth factor expression in C3H/HeJ-host GVHD mice were significantly decreased compared with C3H/HeN-host GVHD mice.

CONCLUSIONS

Our results indicated that host TLR-4 is crucial for the induction of tissue protective factors and for protection against intestinal cell apoptosis during acute GVHD.

Disruption of hepatocyte growth factor/c-Met signaling enhances pancreatic beta-cell death and accelerates the onset of diabetes

OBJECTIVE

To determine the role of hepatocyte growth factor (HGF)/c-Met on β-cell survival in diabetogenic conditions in vivo and in response to cytokines in vitro.

RESEARCH DESIGN AND METHODS

We generated pancreas-specific c-Met-null (PancMet KO) mice and characterized their response to diabetes induced by multiple low-dose streptozotocin (MLDS) administration. We also analyzed the effect of HGF/c-Met signaling in vitro on cytokine-induced β-cell death in mouse and human islets, specifically examining the role of nuclear factor (NF)-κB.

RESULTS

Islets exposed in vitro to cytokines or from MLDS-treated mice displayed significantly increased HGF and c-Met levels, suggesting a potential role for HGF/c-Met in β-cell survival against diabetogenic agents. Adult PancMet KO mice displayed normal glucose and β-cell homeostasis, indicating that pancreatic c-Met loss is not detrimental for β-cell growth and function under basal conditions. However, PancMet KO mice were more susceptible to MLDS-induced diabetes. They displayed higher blood glucose levels, marked hypoinsulinemia, and reduced β-cell mass compared with wild-type littermates. PancMet KO mice showed enhanced intraislet infiltration, islet nitric oxide (NO) and chemokine production, and β-cell apoptosis. c-Met-null β-cells were more sensitive to cytokine-induced cell death in vitro, an effect mediated by NF-κB activation and NO production. Conversely, HGF treatment decreased p65/NF-κB activation and fully protected mouse and, more important, human β-cells against cytokines.

CONCLUSIONS

These results show that HGF/c-Met is critical for β-cell survival by attenuating NF-κB signaling and suggest that activation of the HGF/c-Met signaling pathway represents a novel strategy for enhancing β-cell protection.

Can we protect the gut in critical illness? The role of growth factors and other novel approaches

The intestine plays a central role in the pathophysiology of critical illness and is frequently called the "motor" of the systemic inflammatory response. Perturbations to the intestinal barrier can lead to distant organ damage and multiple organ failure. Therefore, identifying ways to preserve intestinal integrity may be of paramount importance. Growth factors and other peptides have emerged as potential tools for modulation of intestinal inflammation and repair due to their roles in cellular proliferation, differentiation, migration, and survival. This review examines the involvement of growth factors and other peptides in intestinal epithelial repair during critical illness and their potential use as therapeutic targets.

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 suppresses proinflammatory NFkappaB activation through GSK3beta inactivation in renal tubular epithelial cells

Activation of NFkappaB is a fundamental cellular event central to all inflammatory diseases. Hepatocyte growth factor (HGF) ameliorates both acute and chronic inflammation in a multitude of organ systems through modulating NFkappaB activity; nevertheless, the exact molecular mechanism remains uncertain. Here we report that HGF through inactivation of GSK3beta suppresses NFkappaB p65 phosphorylation specifically at position Ser-468. The Ser-468 of RelA/p65 situates in a GSK3beta consensus motif and could be directly phosphorylated by GSK3beta both in vivo and in vitro, signifying Ser-468 of RelA/p65 as a putative substrate for GSK3beta. In addition, the C terminus of RelA/p65 harbors a highly conserved domain homologue of the consensus docking sequence for GSK3beta. Moreover, this domain was required for efficient phosphorylation of Ser-468 and was indispensable for the physical interaction between RelA/p65 and GSK3beta. HGF substantially intercepted this interaction by inactivating GSK3beta. Functionally, phosphorylation of Ser-468 of RelA/p65 was required for the induced expression of a particular subset of proinflammatory NFkappaB-dependent genes. Diminished phosphorylation at Ser-468 by HGF resulted in a gene-specific inhibition of these genes' expression. The action of HGF on proinflammatory NFkappaB activation was consistently mimicked by a selective GSK3beta inhibitor or GSK3beta knockdown by RNA interference but largely abrogated in cells expressing the mutant uninhibitable GSK3beta. Collectively, our findings suggest that HGF has a potent suppressive effect on NFkappaB activation, which is mediated by GSK3beta, an important signaling transducer controlling RelA/p65 phosphorylation specificity and directing the transcription of selective proinflammatory cytokines implicated in inflammatory kidney disease.

Allogeneic bone marrow transplantation for hepatocellular carcinoma: hepatocyte growth factor suppresses graft-vs.-host disease

Allogeneic bone-marrow transplantation (BMT) can induce a powerful graft-vs.-tumor (GVT) effect not only on hematological malignancies but also on solid tumors. However, graft-vs.-host disease (GVHD) is a major complication of allogeneic BMT. We assessed GVT effect on hepatocellular carcinoma (HCC) and the effects of hepatocyte growth factor (HGF) gene transduction on GVHD in HCC transplanted mice. (C57BL/6 x C3H/HeJ)F(1)(B6C3F1, H-2(bxk)) mice were used as recipients and C3H/HeJ(H-2(k)) mice were used as donors. Hepa1-a (a C57L mouse-derived hepatoma cell, H-2(b)) was subcutaneously injected into the recipient mice. Tumor bearing mice were treated in the following ways: group 1, no treatment; group 2, total body irradiation (TBI); group 3, TBI and BMT; group 4, TBI and BMT with empty vector; group 5, TBI and BMT with HGF gene transduction; group 6, TBI and BMT with administration of FK506, a representative immunosuppressive agent. Acute GVHD was assessed by histological examination of the liver, small intestines, and large intestines. Tumor growth was markedly suppressed in mice that received an allogeneic BMT. Donor-derived CD8(+) T cells had infiltrated into the tumor, and cytotoxic CD8(+) T cells against HCC were present. However, among the four groups that received a BMT, this suppressive effect was weaker in group 6 compared with the other three groups (groups 3, 4, and 5). HGF gene transduction improved GVHD while preserving the GVT effects. Allogeneic BMT markedly suppresses the growth of HCC. Simultaneous HGF gene transfer can suppress GVHD while preserving the GVT effect.

Hepatocyte growth factor promotes colonic epithelial regeneration via Akt signaling

Hepatocyte growth factor (HGF) can promote the regeneration of injured organs, including HGF gene therapy by electroporation (EP) for liver injury. In this study, we investigated the effect of HGF on dextran sulfate sodium-induced colitis and tried to clarify the regenerative mechanisms of colonic epithelial cells and the signaling pathway involved. Colitis was induced by dextran sulfate sodium in mice, together with HGF gene transfer by EP. On day 10, the colitis was evaluated histologically and by Western blot analysis. The colonic epithelial cell line MCE301 was exposed to HGF protein, and its proliferation and activated signaling pathway were analyzed. In vivo, the histological score improved and the number of Ki-67-positive epithelial cells increased in the HGF-treated mice compared with the controls. Western blot analysis showed enhanced expression of phospho-Akt in the HGF-treated mice compared with the controls. In vitro, HGF stimulated the proliferation of MCE301 cells. There was enhanced phospho-Akt expression for more than 48 h after HGF stimulation, although phospho-ERK1/2 was enhanced for only 10 min. LY-294002 or Akt small interfering RNA suppressed cell proliferation induced by HGF. Thus HGF induces the proliferation of colonic epithelial cells via the phosphatidylinositol 3-kinase/Akt signaling pathway. HGF gene therapy can attenuate acute colitis via epithelial cell proliferation through the PI3K/Akt pathway. These data suggested that HGF gene therapy by EP may be effective for the regeneration and repair of injured epithelial cells in inflammatory bowel disease.

Increased expression of midkine in the rat colon during healing of experimental colitis

Midkine (MK) is a unique growth and differentiation factor that modulates the proliferation and migration of various cells; however, little is known regarding its relationship to intestinal diseases. The aim of this study was to investigate MK expression and its role in dextran sulfate sodium (DSS)-induced colitis in rats. The expressions of MK, receptor-like protein-tyrosine phosphatase (RPTP)-beta, and proinflammatory cytokines were examined in rat colonic tissues after the development of DSS-induced colitis using Northern blotting, immunohistochemistry, and laser-capture microdissection (LCM) coupled with RT-PCR. The effects of MK on the migration of intestinal epithelial cells (IEC-6) were also evaluated in vitro using an intestinal wound repair model. MK expression was significantly increased in damaged colonic mucosa, mainly from day 3 to day 5 after the end of DSS administration, with abundant MK immunoreactive signals detected in submucosal fibroblasts. Expressions of proinflammatory cytokines were most strongly induced on day 1, which preceded the augmentation of MK expression. Results of LCM coupled with RT-PCR clearly indicated RPTP-beta expression in colonic epithelial cells. The migration assay showed that wound repair in the MK-treated groups was accelerated dose dependently. The present results showed for the first time that intestinal inflammation upregulates the MK-RPTP-beta system, which may stimulate mucosal regeneration during the process of healing of colitis. Additional investigations regarding the role of MK may contribute to the development of new options for the treatment of inflammatory bowel diseases.

Hepatocyte growth factor suppresses acute renal inflammation by inhibition of endothelial E-selectin

Vascular endothelial activation, marked by de novo expression of E-selectin, is an early and essential event in the process of leukocyte extravasation and inflammation. Evidence suggests that hepatocyte growth factor (HGF) ameliorates inflammation in animal models of renal disease, implying that HGF might inhibit specific components of the inflammatory response. This study examined the effect of HGF on endothelial E-selectin expression in acute inflammation induced by tumor necrosis factor (TNF)-α. In vitro, HGF suppressed TNF-α-induced cell surface expression of E-selectin in human umbilical vein endothelial cells (HUVEC) and inhibited E-selectin mediated monocytic adhesion to endothelial monolayers. HGF activated phosphatidylinositol 3-kinase (PI3K)–Akt that in turn inhibited its downstream transducer glycogen synthase kinase (GSK)3. Blockade of the PI3K–Akt pathway with specific inhibitors abrogated HGF induced inhibitory phosphorylation of GSK3 and suppression of E-selectin. In addition, selective inhibition of GSK3 activity by lithium suppressed TNF-α-induced E-selectin expression and monocytic adhesion, reminiscent of the action of HGF. Moreover, ectopic expression of an uninhibitable mutant GSK3β, in which the regulatory serine-9 is replaced by alanine, abolished HGF's suppressive effect on endothelial E-selectin. In vivo, administration of exogenous HGF reduced endothelial expression of E-selectin induced by bolus injection of TNF-α. This was associated with less sequestration of circulating fluorescence-labeled macrophages in the kidney. These findings suggest that HGF ameliorates acute renal inflammation in part by downregulating E-selectin mediated macrophage adhesion to the inflamed endothelium.

Anti-inflammatory effect of hepatocyte growth factor in chronic kidney disease: targeting the inflamed vascular endothelium

Recent studies show that hepatocyte growth factor (HGF) has potent anti-inflammatory effects in multiple animal models of disease in various organ systems, including the kidney, suggesting that HGF may suppress a common proinflammatory process. The aim of this study was to examine the molecular mechanism of HGF's anti-inflammatory actions in a model of chronic kidney disease. Beginning 2 wk after subtotal nephrectomy, rats received a continuous infusion of recombinant HGF, neutralization of endogenous HGF by daily injection of an anti-HGF antibody, or preimmune IgG for an additional 2 wk. The effects on inflammation and injury were examined. HGF administration ameliorated whereas neutralizing endogenous HGF worsened renal inflammation in remnant kidneys. This was accompanied by parallel alterations in endothelial activation and inflammation, marked respectively by de novo E-selectin expression in renal vascular endothelium and leukocyte adhesion to endothelium. In vitro, HGF abrogated monocyte adhesion to TNF-alpha-activated endothelial monolayers and suppressed endothelial expression of E-selectin, which depended on NF-kappaB signaling. In addition, HGF suppressed NF-kappaB reporter gene activity that was induced by TNF-alpha and counteracted TNF-alpha-elicited NF-kappaB interaction with kappaB elements at the E-selectin gene level. Dissection of the NF-kappaB signaling cascade revealed that suppression of NF-kappaB depended on HGF's inhibitory action on NF-kappaB and IkappaB phosphorylation and IkappaB degradation. In vivo, continuous infusion of exogenous HGF markedly diminished sequestration of circulating fluorescence-labeled macrophages in the remnant kidney, mimicking the action of an E-selectin blocking antibody. These findings suggest that HGF has potent and direct anti-inflammatory effects on the basis of suppression of NF-kappaB activation and downstream endothelial inflammation.

Role of angiogenesis in inflammatory bowel disease

Several studies have shown alterations in vascular anatomy and physiology in inflammatory bowel disease (IBD). These findings, together with the observed upregulation of the mediators of angiogenesis in IBD patients, suggest that angiogenesis possibly contributes to the initiation and perpetuation of IBD. There is considerable evidence of an interrelationship between the mechanisms of angiogenesis and chronic inflammation in IBD. The increased expression of endothelial junction adhesion molecules found in IBD patients indicates the presence of active angiogenesis. Evidence that angiogenesis is involved in IBD was also obtained from animal models of colitis, most notably from studies of angiogenesis inhibition. Serum levels of vascular endothelial growth factor (VEGF) correlate with disease activity in human IBD and fall with the use of steroids, thalidomide, or infliximab. Pharmacological inhibition of angiogenesis, therefore, has the potential to be a therapeutic strategy in IBD. This review outlines the evidence that the rate of angiogenesis is increased in the inflamed intestine in IBD and proposes lines for future research in this field.

Naked gene therapy of hepatocyte growth factor for dextran sulfate sodium-induced colitis in mice

Ulcerative colitis (UC) is progressive and relapsing disease. To explore the therapeutic effects of naked gene therapy of hepatocyte growth factor (HGF) on UC, the SRalpha promoter driving HGF gene was intrarectally administered to the mice in which colitis was induced by dextran sulfate sodium (DSS). Expression of the transgene was seen in surface epithelium, lamina propria, and muscularis mucosae. The HGF-treated mice showed reduced colonic mucosal damage and increased body weights, compared with control mice (P < 0.01 and P < 0.05, respectively). The HGF-treated mice displayed increased number of PCNA-positive cells and decreased number of apoptotic cells than in control mice (P < 0.01, each). Phosphorylated AKT was dramatically increased after HGF gene administration, however, phosphorylated ERK1/2 was not altered. Microarray analysis revealed that HGF induced expression of proliferation- and apoptosis-associated genes. These data suggest that naked HGF gene delivery causes therapeutic effects through regulation of many downstream genes.

Mucosal repair and growth factors: recombinant human hepatocyte growth factor as an innovative therapy for inflammatory bowel disease

The repair of intestinal mucosal injuries is a tightly regulated process involving epithelial restitution, cell proliferation and maturation, and the dedifferentiation of epithelial cells. Deeper injuries also require additional repair mechanisms, including inflammatory processes, angiogenesis, and extracellular-matrix deposition. Once intestinal mucosal injury occurs, numerous growth factors and cytokines, including hepatocyte growth factor (HGF), keratinocyte growth factor, endothelial growth factor, epidermal growth factor, transforming growth factor-beta1, intestinal trefoil factor, interleukin (IL)-1, and IL-2, are induced in both the intestinal lumen and submucosa, and these factors cooperatively stimulate epithelial mucosal repair. HGF, a major agent promoting hepatocyte proliferation, also modulates intestinal epithelial cell proliferation and migration, leading to the acceleration of intestinal mucosal repair. Additionally, the proteolytic activation of HGF, which is mediated by HGF activator, is essential for the regeneration of injured intestinal mucosa. Recently, several studies have shown that the administration of recombinant human HGF or HGF gene therapy abrogates disease severity in several animal models of inflammatory bowel disease (IBD). Recombinant human HGF will soon be available for administration to patients with fulminant hepatic failure. Although additional preclinical biological studies are required, HGF has the potential to be an important new treatment modality promoting intestinal mucosal repair in patients with IBD.