Attenuation of mouse acute colitis by naked hepatocyte growth factor gene transfer into the liver

Dental pulp stem cells overexpressing hepatocyte growth factor facilitate the repair of DSS-induced ulcerative colitis

Background

Ulcerative colitis (UC) is a chronic and recurrent disease without satisfactory treatment strategies. Dental pulp stem cell (DPSC) transplantation has been proposed as a potential therapy for UC. This study aimed to investigate the therapeutic effects of the rat hepatocyte growth factor (HGF) gene transduced into DPSCs for UC.

Methods

The therapeutic effects of HGF-DPSCs transplanted intravenously into a rat model of UC induced by 5% dextran sulphate sodium (DSS) were compared with the other treatment groups (LV-HGF group, DPSCs group and GFP-DPSCs group). Immunofluorescence and immunohistochemistry were used to observe the localization and proliferation of HGF-DPSCs at the site of colon injury. The expression levels of inflammatory factors were detected by real-time quantitative PCR (RT-PCR) and western blotting. The oxidative stress markers were detected by ELISA. DAI scores and body weight changes were used to macroscopically evaluate the treatment of rats in each group.

Results

Immunofluorescence and immunohistochemistry assays showed that HGF-DPSCs homed to colon injury sites and colocalized with intestinal stem cell (ISC) markers (Bmi1, Musashi1 and Sox9) and significantly promoted protein expression (Bmi1, Musashi1, Sox9 and PCNA). Anti-inflammatory cytokine (TGF-β and IL-10) expression was the highest in the HGF-DPSCs group compared with the other treatment groups, while the expression of pro-inflammatory cytokines (TNF-α and INF-γ) was the lowest. Additionally, the oxidative stress response results showed that malondialdehyde (MDA) and myeloperoxidase (MPO) expression decreased while superoxide dismutase (SOD) expression increased, especially in the HGF-DPSCs group. The DAI scores showed a downward trend with time in the five treatment groups, whereas body weight increased, and the changes were most prominent in the HGF-DPSCs group.

Conclusions

The study indicated that HGF-DPSCs can alleviate injuries to the intestinal mucosa by transdifferentiating into ISC-like cells, promoting ISC-like cell proliferation, suppressing inflammatory responses and reducing oxidative stress damage, which provides new ideas for the clinical treatment of UC.

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.

Pivotal Role of Carbohydrate Sulfotransferase 15 in Fibrosis and Mucosal Healing in Mouse Colitis

Induction of mucosal healing (MH) is an important treatment goal in inflammatory bowel disease (IBD). Although the molecular mechanisms underlying MH in IBD is not fully explored, local fibrosis would contribute to interfere mucosal repair. Carbohydrate sulfotransferase 15 (CHST15), which catalyzes sulfation of chondroitin sulfate to produce rare E-disaccharide units, is a novel mediator to create local fibrosis. Here we have used siRNA-based approach of silencing CHST15 in dextran sulfate sodium (DSS) induced colitis in mice, human colon fibroblasts and cancer cell lines. In a DSS-induced acute colitis model, CHST15 siRNA reduced CHST15 mRNA in the colon, serum IL-6, disease activity index (DAI) and accumulation of F4/80+ macrophages and ER-TR7+ fibroblasts, while increased Ki-67+ epithelial cells. In DSS-induced chronic colitis models, CHST15 siRNA reduced CHST15 mRNA in the colon, DAI, alpha-smooth muscle actin+ fibroblasts and collagen deposition, while enhanced MH as evidenced by reduced histological and endoscopic scores. We also found that endoscopic submucosal injection achieved effective pancolonic delivery of CHST15 siRNA in mice. In human CCD-18 Co cells, CHST15 siRNA inhibited the expression of CHST15 mRNA and selectively reduced E-units, a specific product biosynthesized by CHST15, in the culture supernatant. CHST15 siRNA significantly suppressed vimentin in both TGF-ß-stimulated CCD18-Co cells and HCT116 cells while up-regulated BMP7 and E-cadherin in HCT116 cells. The present study demonstrated that blockade CHST15 represses colonic fibrosis and enhances MH partly though reversing EMT pathway, illustrating a novel therapeutic opportunity to refractory and fibrotic lesions in IBD.

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.

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.

Mesenchymal stem cells overexpressing hepatocyte growth factor (HGF) inhibit collagen deposit and improve bladder function in rat model of bladder outlet obstruction

Bladder outlet obstruction (BOO) caused by collagen deposit is one of the most common problems in elderly male. This study was performed to examine the capability of human mesenchymal stem cells (MSCs) overexpressing hepatocyte growth factor (HGF) to inhibit collagen deposition in rat model of bladder outlet obstruction (BOO). HGF is known for its antifibrotic effect and the most promising agent for treating bladder fibrosis. BM3.B10 stable immortalized human MSC line (B10) was transduced to encode human HGF with a retroviral vector was prepared (B10.HGF). Two weeks after the onset of BOO, B10, and B10.HGF cells were injected into the rat's bladder wall. After 4 weeks, bladder tissues were harvested and Masson's trichrome staining was performed. Transgene expression in HGF-expressing B10 cells was demonstrated by reverse transcriptase polymerase chain reaction and immunohistochemical staining, and the high levels of HGF secreted by B10.HGF cells was confirmed by ELISA. The mean bladder weight in BOO rats was 5.8 times of the normal controls, while in animals grafted with B10.HGF cells, the weight was down to four times of the control [90.2 ± 1.6 (control), 89.9 ± 2.8 (sham), 527.9 ± 150.9 (BOO), 447.7 ± 41.0 (BOO + B10), and 362.7 ± 113.2 (BOO + B10.HGF)]. The mean percentage of collagen area increased in BOO rats, while in the animals transplanted with B10.HGF cells, the collagen area decreased to the normal control level [12.2 ± 1.3, (control), 12.8 ± 1.1 (sham), 26.6 ± 2.7 (BOO), 19.9 ± 6.0 (BOO + B10), and 13.3 ± 2.1 (BOO + B10.HGF)]. The expression of collagen and TGF-b protein increased after BOO, while the expression of HGF and c-met protein increased in the group with B10.HGF transplantation after BOO. Intercontraction interval decreased after BOO, but it recovered after B10.HGF transplantation. Maximal voiding pressure (MVP) increased after BOO, and it recovered to levels of the normal control after transplantation of B10.HGF cells. Residual urine volume (RU) increased after BOO, but the RU increase was not reversed by transplantation of B10.HGF cells. Human MSCs overexpressing HGF inhibited collagen deposition and improved cystometric parameters in bladder outlet obstruction of rats. The present study indicates that transplantation of MSCs modified to overexpress HGF could serve as a novel therapeutic strategy against bladder fibrosis in patients with bladder outlet obstruction.

Curcumin ameliorates cardiac inflammation in rats with autoimmune myocarditis

Curcumin is a natural polyphenolic compound abundant in the rhizome of the perennial herb turmeric, Curcuma longa. It is commonly used as a dietary spice and coloring agent in cooking, and is used anecdotally as an herb in traditional Indian and Chinese medicine. It has been reported that curcumin has the potential to protect against cardiac inflammation through suppression of GATA-4 and nuclear factor-κB (NF-κB); however, no study to date has addressed the effect of curcumin on experimental autoimmune myocarditis (EAM) in rats. In this study, 8-week-old male Lewis rats were immunized with cardiac myosin to induce EAM. They were then divided randomly into a treatment or vehicle group and orally administrated curcumin (50 mg/kg/d) or 1% gum arabic, respectively, for 3 weeks after myosin injection. We performed hemodynamic, echocardiographic, hematoxylin and eosin staining, mast cell staining and Western blotting studies to evaluate the protective effect of curcumin in the acute phase of EAM. Cardiac functional parameters measured by hemodynamic and echocardiographic studies were significantly improved by curcumin treatment. Furthermore, curcumin reduced the heart weight-to-body weight ratio, area of inflammatory lesions and the myocardial protein level of NF-κB, interleukin (IL)-1β, tumor necrosis factor (TNF)-α and GATA-4. Our results indicate that curcumin has the potential to protect against cardiac inflammation through suppression of IL-1β, TNF-α, GATA-4 and NF-κB expresses, and may provide a novel therapeutic strategy for autoimmune myocarditis.

Analysis of intestinal fibrosis in chronic colitis in mice induced by dextran sulfate sodium

Fibrogenic mesenchymal cells including fibroblasts and myofibroblasts play a key role in intestinal fibrosis, however, their precise role is largely unknown. To investigate their role in intestinal fibrosis, we analyzed the lesions of chronic colitis in C57BL/6 (B6) mice induced by dextran sulfate sodium (DSS). B6 mice exposed to single cycle administration of DSS for 5 days developed acute colitis that progressed to severe chronic inflammation with dense infiltrates of mononuclear cells, irregular epithelial structure, thickening of colonic wall, and persistent deposits of collagen. Increased mRNA expressions of proinflammatory cytokines are correlated with extensive cellular infiltration, and the mRNA expressions of collagen 1, transforming growth factor (TGF)-β, and matrix metalloproteinases were also enhanced in the colon. In the colon of chronic DSS colitis, fibroblasts (vimentin(+), α-smooth muscle actin (α-SMA)(-)) were increased in both mucosal and submucosal layers, while myofibroblasts (vimentin(+), α-SMA(+)) were increased in mucosal but not in submucosal layers. Primary mouse subcutaneous fibroblast cultures experiments revealed that exogenously added TGF-β 1 substantially augmented the expressions of both vimentin and α-SMA proteins with increased production of collagen. In conclusion, profibrogenic mesenchymal cells play an important role in the development of intestinal fibrosis in this chronic DSS-induced colitis model.

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.

Rectal administration of tranilast ameliorated acute colitis in mice through increased expression of heme oxygenase-1

Mast cells play a key role in the pathophysiology of inflammatory bowel disease (IBD). Tranilast, a mast cell stabilizer, has been empirically used for IBD in Japan, but its precise role in the treatment of IBD is largely unknown. To investigate the role of tranilast for the treatment of IBD, tranilast was administered intrarectally to mice with dextran sulfate sodium (DSS)-induced colitis. Tranilast ameliorated DSS colitis clinically and pathologically, as demonstrated by decreased number and degranulation of mast cells in the colon. mRNA expression was increased for tumor necrosis factor-alpha, interferon-gamma and interleukin (IL)-6, and decreased for IL-10 in the colon of DSS colitis mice. In contrast, tranilast markedly decreased expression of mRNAs for the pro-inflammatory cytokines, and increased that of the anti-inflammatory cytokines. Moreover, tranilast increased heme oxygenase (HO)-1 expression on colonic epithelial cells as well as on colon-infiltrating cells of DSS colitis. In conclusion, tranilast ameliorated DSS colitis by regulating mast cell degranulation, decreasing inflammatory cytokines and increasing anti-inflammatory cytokines. Tranilast might exert these effects partly through enhanced HO-1 expression in the colon, suggesting a potential adjunctive therapy for IBD.

Therapeutic effect of transplanting beta(2)m(-)/Thy1(+) bone marrow-derived hepatocyte stem cells transduced with lentiviral-mediated HGF gene into CCl(4)-injured rats

BACKGROUND

beta(2)m(-)/Thy1(+) bone marrow-derived hepatocyte stem cells (BDHSCs) isolated from the bone marrow of cholestatic rats by magnetic bead cell sorting consistently express characteristics of both stem and liver cells. These stem cells may be good vehicles for gene transfer. Administration of exogenous hepatocyte growth factor (HGF) may be potentially useful for the treatment of liver fibrosis. Because lentiviral vectors integrate stably into the host-cell genome of nondividing and dividing cells, it may efficiently transfect beta(2)m(-)/Thy1(+) BDHSCs in vitro and secrete high-level HGF consistently. Transplantation of beta(2)m(-)/Thy1(+) BDHSCs transduced with lentiviral vectors containing the HGF gene may reduce liver fibrosis in rats.

METHODS

Lentiviral vectors expressing HGF were constructed and used to transduce beta(2)m(-)/Thy1(+) BDHSCs sorted from cholestatic rats in vitro. Transduction efficiency was evaluated and then these cells were transplanted into rats through the portal vein. Liver function as well as histological and immunohistochemical examinations were carried out to assess the therapeutic efficacy on liver fibrosis.

RESULTS

We demonstrated that high-level exogenous HGF was detected in supernatants after beta(2)m(-)/Thy1(+) BDHSCs were transfected with lentiviral vectors expressing HGF. Transplantation of transduced beta(2)m(-)/Thy1(+) BDHSCs significantly enhanced liver function and attenuated liver fibrosis in vivo.

CONCLUSIONS

The present study indicates that transplantation of beta(2)m(-)/Thy1(+) BDHSCs overexpressing the HGF gene may offer a novel approach for promoting liver function and reverse liver fibrosis.

Distinct genetic risk based on association of MET in families with co-occurring autism and gastrointestinal conditions

OBJECTIVE

In addition to the core behavioral symptoms of autism spectrum disorder, many patients present with complex medical conditions including gastrointestinal dysfunction. A functional variant in the promoter of the gene encoding the MET receptor tyrosine kinase is associated with autism spectrum disorder, and MET protein expression is decreased in the temporal cortex of subjects with autism spectrum disorder. MET is a pleiotropic receptor that functions in both brain development and gastrointestinal repair. On the basis of these functions, we hypothesized that association of the autism spectrum disorder-associated MET promoter variant may be enriched in a subset of individuals with co-occurring autism spectrum disorder and gastrointestinal conditions.

PATIENTS AND METHODS

Subjects were 918 individuals from 214 Autism Genetics Resource Exchange families with a complete medical history including gastrointestinal condition report. Genotypes at the autism spectrum disorder-associated MET promoter variant rs1858830 were determined. Family-based association test and chi(2) analyses were used to determine the association of MET rs1858830 alleles with autism spectrum disorder and the presence of gastrointestinal conditions.

RESULTS

In the entire 214-family sample, the MET rs1858830 C allele was associated with both autism spectrum disorder and gastrointestinal conditions. Stratification by the presence of gastrointestinal conditions revealed that the MET C allele was associated with both autism spectrum disorder and gastrointestinal conditions in 118 families containing at least 1 child with co-occurring autism spectrum disorder and gastrointestinal conditions. In contrast, there was no association of the MET polymorphism with autism spectrum disorder in the 96 families lacking a child with co-occurring autism spectrum disorder and gastrointestinal conditions. chi(2) analyses of MET rs1858830 genotypes indicated over-representation of the C allele in individuals with co-occurring autism spectrum disorder and gastrointestinal conditions compared with non-autism spectrum disorder siblings, parents, and unrelated controls.

CONCLUSION

These results suggest that disrupted MET signaling may contribute to increased risk for autism spectrum disorder that includes familial gastrointestinal dysfunction.

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.

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.