Hepatocyte growth factor gene therapy of liver cirrhosis in rats

Fragmin/protamine microparticles to adsorb and protect HGF and to function as local HGF carriers in vivo

The clinical efficacy of hepatocyte growth factor (HGF) in tissue repair can be greatly enhanced by high affinity, biocompatible drug carriers that maintain the bioactivity and regulate release at the target site. We produced 0.5-3.0 μm fragmin (low molecular weight heparin)/protamine microparticles (F/P MPs) as carriers for the controlled release of HGF. F/P MPs immobilized more than 3 μg of HGF per mg of MPs and gradually released the absorbed HGF into the medium with a half-release time of approximately 5 days. Compared with HGF alone, HGF-containing F/P MPs substantially enhanced the mitogenic effect of HGF on cultured human microvascular endothelial cells, by prolonging the biological half-life, and its conjugation to F/P MPs protected HGF from heat and proteolytic inactivation. F/P MPs disappeared 8 days after subcutaneous injection in mice, suggesting that they are rapidly biodegraded. Furthermore, the number of large (diameter ≥200 μm or containing ≥ 100 erythrocytes) and medium (diameter 20-200 μm or containing 10-100 erythrocytes) lumen capillaries 8 days after injection of HGF-containing F/P MPs was significantly higher than that after injection of HGF or F/P MPs alone. Furthermore, the number of small (diameter ≤ 20 μm or containing 1-10 erythrocytes) lumen capillaries was significantly higher 4 days after injection of HGF-containing F/P MPs. This increased angiogenic activity of HGF in vivo is probably due to both sustained local release and protection against biodegradation by the F/P MPs. Thus, F/P MPs may be useful and safe HGF carriers that facilitate cell proliferation and vascularization at sites of tissue damage.

Pharmacokinetic modeling of hepatocyte growth factor in experimental animals and humans

Hepatocyte growth factor (HGF) is under development for treatment of renal failure. This study was designed to clarify changes in HGF pharmacokinetics in renal failure and to establish a pharmacokinetic model applicable to single and repeated doses. The plasma concentration profile in mice with glycerol-induced acute renal failure was similar to that in normal mice, indicating a minimal contribution of kidney to systemic clearance of HGF. Nevertheless, accumulation of fluorescein-4-isocyanate-labeled HGF in renal tubules in both cases suggests the occurrence of efficient endocytosis of HGF in kidney. A pharmacokinetic model including plasma and liver compartments was constructed, incorporating both high- and low-affinity receptors for association and subsequent endocytosis of HGF because HGF is eliminated via specific receptor c-Met and heparin-like substance. The model well explained the plasma concentration profiles at all doses examined after bolus injection in animals and humans, and those during infusion in rodents. It includes externalization of receptors, which is negatively regulated by HGF, and can explain the gradual increase in trough concentration during repeated dosing in monkeys. Overall pharmacokinetic profiles of HGF are governed by at least two receptors and are well described by this pharmacokinetic model, which should assist in safe management of clinical trials.

Differential expression of wound fibrotic factors between facial and trunk dermal fibroblasts

Clinically, wounds on the face tend to heal with less scarring than those on the trunk, but the causes of this difference have not been clarified. Fibroblasts obtained from different parts of the body are known to show different properties. To investigate whether the characteristic properties of facial and trunk wound healing are caused by differences in local fibroblasts, we comparatively analyzed the functional properties of superficial and deep dermal fibroblasts obtained from the facial and trunk skin of seven individuals, with an emphasis on tendency for fibrosis. Proliferation kinetics and mRNA and protein expression of 11 fibrosis-associated factors were investigated. The proliferation kinetics of facial and trunk fibroblasts were identical, but the expression and production levels of profibrotic factors, such as extracellular matrix, transforming growth factor-β1, and connective tissue growth factor mRNA, were lower in facial fibroblasts when compared with trunk fibroblasts, while the expression of antifibrotic factors, such as collagenase, basic fibroblast growth factor, and hepatocyte growth factor, showed no clear trends. The differences in functional properties of facial and trunk dermal fibroblasts were consistent with the clinical tendencies of healing of facial and trunk wounds. Thus, the differences between facial and trunk scarring are at least partly related to the intrinsic nature of the local dermal fibroblasts.

Coexpression of Smad7 and UPA attenuates carbon tetrachloride-induced rat liver fibrosis

BACKGROUND

There is a great need for developing novel therapies to treat liver fibrosis. Previous studies showed that both Smad7 and uPA were inhibitors of liver fibrosis. Therefore, we explored the therapeutic effects of combinational gene therapy with Smad7 and uPA on CCl4-induced liver fibrosis.

MATERIAL/METHODS

Smad7 and uPA genes were cloned into an adenovirus vector. To observe the therapeutic effects of coexpression of Smad7 and uPA genes, the recombinant adenovirus were delivered into CCL4-induced fibrosis models. Fibrillar collagen, hydroxyproline, α-SMA, TGF-β1, MMP-13, TIMP-1, HGF and PCNA were detected to evaluate the fibrosis and to explore the mechanisms underlying the treatment with Smad7 and uPA.

RESULTS

The results showed that single Smad7 or uPA adenovirus reduced CCL4 induced liver fibrosis significantly; while combination of Smad7 and uPA had more significant therapeutic effect on CCl4 induced liver fibrosis. Then the markers underlying the therapeutic effect of combination of Smad7 and uPA were also explored. Over-expression of Smad7 and uPA inhibited the expression of α-SMA and TGF- β1 significantly. Combinational gene therapy also enhanced extracellular matrix degradation by increasing the expression of MMP-13, inhibiting TIMP-1 expression, and promoted hepatocyte proliferation, while single Smad7 or uPA only induced part of these changes.

CONCLUSIONS

These results suggest that combinational gene therapy with Smad7 and uPA inhibited CCl4-induced rat liver fibrosis by simultaneously targeting multiple pathogenic pathways.

Low serum cultured adipose tissue-derived stromal cells ameliorate acute kidney injury in rats

Current studies suggest that mesenchymal stromal cells (MSCs) improve acute kidney injury (AKI) via paracrine/endocrine effects. We established human adipose tissue-derived stromal cells (hASCs) cultured in low (2%) serum (hLASCs), which have great potential of tissue regeneration. The present study was performed to investigate the therapeutic effects of hLASCs on AKI and to clarify the mechanisms involved. In low serum, hASCs proliferated well, while human bone marrow-derived stromal cells (hBMSCs) did not. hLASCs secreted higher levels of hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) than did hASCs cultured in high (20%) serum (hHASCs) or hBMSCs cultured in high serum (hHBMSCs). AKI was induced in nude rats by folic acid, and hLASCs, hHASCs or control medium were administered into the renal subcapsules. hLASCs significantly attenuated acute renal damage, while hHASCs showed far less effect. Furthermore, interstitial fibrosis observed on day 14 was less pronounced in the hLASCs group. Cell tracking experiment showed no evidence of transdifferentiation. Intravenous injection of hLASCs or hHBMSCs or subcapsular injection of hHBMSCs did not ameliorate AKI. Concerning the mechanisms, our in vivo experiments showed that HGF knockdown by siRNA impaired the ability of hLASCs to protect the kidney from acute injury whereas VEGF knockdown did not. In conclusion, hLASCs, but not hHASCs or hHBMSCs, ameliorated AKI via paracrine effects, and HGF is one of the key mediators.

Interleukin-22 induces hepatic stellate cell senescence and restricts liver fibrosis in mice

Interleukin (IL)-22 is known to play a key role in promoting antimicrobial immunity, inflammation, and tissue repair at barrier surfaces by binding to the receptors, IL-10R2 and IL-22R1. IL-22R1 is generally thought to be expressed exclusively in epithelial cells. In this study, we identified high levels of IL-10R2 and IL-22R1 expression on hepatic stellate cells (HSCs), the predominant cell type involved in liver fibrogenesis in response to liver damage. In vitro treatment with IL-22 induced the activation of signal transducer and activator of transcription (STAT) 3 in primary mouse and human HSCs. IL-22 administration prevented HSC apoptosis in vitro and in vivo, but surprisingly, the overexpression of IL-22 by either gene targeting (e.g., IL-22 transgenic mice) or exogenous administration of adenovirus expressing IL-22 reduced liver fibrosis and accelerated the resolution of liver fibrosis during recovery. Furthermore, IL-22 overexpression or treatment increased the number of senescence-associated beta-galactosidase-positive HSCs and decreased alpha-smooth muscle actin expression in fibrotic livers in vivo and cultured HSCs in vitro. Deletion of STAT3 prevented IL-22-induced HSC senescence in vitro, whereas the overexpression of a constitutively activated form of STAT3 promoted HSC senescence through p53- and p21-dependent pathways. Finally, IL-22 treatment up-regulated the suppressor of cytokine signaling (SOCS) 3 expression in HSCs. Immunoprecipitation analyses revealed that SOCS3 bound p53 and subsequently increased the expression of p53 and its target genes, contributing to IL-22-mediated HSC senescence.

CONCLUSION

IL-22 induces the senescence of HSCs, which express both IL-10R2 and IL-22R1, thereby ameliorating liver fibrogenesis. The antifibrotic effect of IL-22 is likely mediated by the induction of HSC senescence, in addition to the previously discovered hepatoprotective functions of IL-22.

An overview of the c-MET signaling pathway

c-MET is a receptor tyrosine kinase that, after binding with its ligand, hepatocyte growth factor, activates a wide range of different cellular signaling pathways, including those involved in proliferation, motility, migration and invasion. Although c-MET is important in the control of tissue homeostasis under normal physiological conditions, it has also been found to be aberrantly activated in human cancers via mutation, amplification or protein overexpression. This paper provides an overview of the c-MET signaling pathway, including its role in the development of cancers, and provides a rationale for targeting the pathway as a possible treatment option.

Prevention of liver fibrosis and liver reconstitution of DMN-treated rat liver by transplanted EPCs

BACKGROUND

  Using the dimethylnitrosamine (DMN) rat model of induced fibrosis, we investigated whether transfer of in vitro-expanded endothelial progenitor cells (EPCs) could reconstitute liver tissue and protect against liver fibrosis.

MATERIALS AND METHODS

  Low-density, adherent, rat bone marrow-derived mononuclear cells were cultured for one week in medium supporting the growth of chemokine (C-X-C motif) receptor 4 (CXCR4)-positive EPCs that were used for transplantation. Test rats were treated with weekly intraperitoneal injections of DMN over a period of 4 weeks. During that period, the rats were also transplanted weekly with in vivo-expanded EPCs.

RESULTS

  Transplanted CXCR4-positive expanded EPCs entered around the portal tracts, fibrous septa and hepatic sinusoids, locations at which stromal cell-derived factor 1 (SDF-1), a ligand attracting CXCR4-positive cells, was expressed nearby. In EPC-transplanted rats, we observed suppression of liver fibrogenesis, reduced deposition of type I collagen and fibronectin, fewer α-smooth muscle actin-positive cells and lower expression of transforming growth factor (TGF)-β. The expression of growth factors promoting hepatic regeneration (hepatocyte growth factor, transforming growth factor-α (TGF-α), epidermal growth factor and vascular endothelial growth factor) was significantly increased in EPC-transplanted rats, resulting in hepatocyte proliferation. Immunohistochemical analyses of eNOS and isolectin B4 demonstrated that the livers of EPC-transplanted animals had markedly increased vascular density, suggesting reconstitution of sinusoidal blood vessels with endothelium. Liver function tests of transaminase, total bilirubin, total protein and albumin demonstrated that normal levels were maintained in EPC-transplanted rats.

CONCLUSIONS

  EPC transplantation effectively promotes the remodelling of tissues damaged by liver fibrosis; it can also reconstitute sinusoids in chronic liver injury.

Autologous cell therapy for cisplatin-induced acute kidney injury by using non-expanded adipose tissue-derived cells

BACKGROUND AIMS

Recent studies have demonstrated that cultured mesenchymal stromal cells derived from adipose tissue are useful for regenerative cell therapy. The stromal vascular fraction (SVF) can be obtained readily without culturing and may be clinically applicable. We investigated the therapeutic effects of SVF and used it in the treatment of acute kidney injury (AKI).

METHODS

Liposuction aspirates were obtained from healthy donors who had provided written informed consent. We harvested the SVF and determined the growth factor secretion and anti-apoptotic ability with conditioned medium. To investigate the effect of SVF on AKI, cisplatin was injected into rats and SVF was administrated into the subcupsula of the kidney.

RESULTS

Both human and rat SVF cells secreted vascular endothelial growth factor-A (VEGF) and hepatocyte growth factor (HGF). Human SVF-conditioned media had an anti-apoptotic effect, which was inhibited by anti-HGF antibody (Ab) but not by anti-VEGF Ab. In vivo, SVF significantly ameliorated renal function, attenuated tubular damage and increased the cortical blood flow speed. In the SVF-treated group, VEGF levels in the cortex and HGF levels in both the cortex and medulla, especially tubules in the medulla, were significantly higher. Immunostaining revealed that SVF cells expressing VEGF and HGF and remained in the subcapsule on day 14.

CONCLUSIONS

The present study demonstrates that a subcapsular injection of non-expanded SVF cells ameliorates rat AKI, and that the mechanism probably involves secretion of renoprotective molecules. Administration of human SVF may be clinically applicable and useful as a novel autologous cell therapy against kidney diseases.

Attenuation of hepatic fibrosis through ultrasound-microbubble-mediated HGF gene transfer in rats

OBJECTIVE

The objective was to explore the feasibility of ultrasound-microbubble-mediated hepatocyte growth factor (HGF) gene transfer for treating rat hepatic fibrosis induced by CCl(4).

METHODS

Forty-eight male SD rats were divided into ultrasound-microbubble-HGF group (U-M-HGF group), ultrasound-HGF group (U-HGF group), microbubble-HGF group (M-HGF group), HGF group (HGF group), CCl(4) group (control group), and normal group. The serum levels of alanine transaminase (ALT), aspartate transaminase (AST), total protein, albumin (ALB), and globulin (GLB) and the ratio of ALB/GLB were determined after treatment. The degree of hepatic fibrosis was evaluated by histopathological numerical scores. The protein expressions of HGF, collagen I, collagen III, and α-smooth muscle antibody (α-SMA) were detected by immunohistochemistry.

RESULTS

Ultrasound-microbubble-mediated HGF therapy significantly reduced the serum level of ALT and AST to 59.88% and 49.18% of the control group, respectively. Ultrasound-microbubble-mediated HGF therapy prevented liver fibrosis, with an obvious decrease in fibrosis areas and extracellular matrix production of collagen I, collagen III, and α-SMA. The gene therapy could induce HGF delivery into the fibrotic liver effectively.

CONCLUSIONS

Ultrasound-microbubble-mediated HGF gene therapy can reduce liver fibrosis, which provides a novel strategy for gene therapy of chronic liver disease.

Influence of allogeneic bone marrow mesenchymal stem cell transplantation on serum levels of HMGB1 in mice with acute live failure

AIM: To explore the influence of allogeneic bone marrow mesenchymal stem cell (BMSC) transpantion on serum levels of high group box protein B1 (HMGB1) in an animal model of acute live failure (ALF).

METHODS: Balb/c mice were given D-galactosamine (D-GaIN) and lipopolysaccharide (LPS) to induce acute liver failure. BMSCs were cultured and purified. Ninety healthy Balb/c mice were randomly assigned to three groups: normal control group, ALF group, and BMSC treatment group. ALT/AST levels were tested 12, 24, and 48 h after treatment, and liver tissue pathological examination was performed after 48 h. The expression of HMGB1 in serum was detected by Western blot.

RESULTS: The survival rate was significantly higher in the BMSC treatment group than in the ALF group (83.3% vs 16.7%, P < 0.05). AST/ALT levels in the ALF group and BMSC treatment group rose significantly at 12 h, peaked at 24 h, and began to fall at 48 h. ALT/AST levels at 12, 24 and 48 h were significantly higher in the ALF group and BMSC treatment group than in the normal group (all P < 0.01), and in the ALF group than in the BMSC treatment group (all P < 0.01). The degeneration and necrosis in liver tissue were less obvious in the BMSC treatment group than in the ALF group. HMGB1 was almost not detectable in normal mouse serum. Serum levels of HMGB1 were significantly higher in the ALF group than in the BMSC treatment group (P < 0.01).

CONCLUSION: BMSC transplantation inhibits HMGB1 expression, reduces liver inflammation, and thereby lowers mortality in mice with ALF.

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.

Inhibition of collagen deposit in obstructed rat bladder outlet by transplantation of superparamagnetic iron oxide-labeled human mesenchymal stem cells as monitored by molecular magnetic resonance imaging (MRI)

Bladder outlet obstruction (BOO) caused by collagen deposit is one of the most common problems in elderly males. The present study is to investigate if human mesenchymal stem cells (MSCs) are capable of inhibiting collagen deposition and improve cystometric parameters in bladder outlet obstruction in rats. Human MSCs were labeled with nanoparticles containing superparamagnetic iron oxide (SPION), and transplanted in rat BOO lesion site. Forty 6-week-old female Sprague-Dawley rats were divided into four groups (group 1: control, group 2: sham operation, group 3: BOO, and group 4: BOO rats receiving SPION-hMSCs). Two weeks after the onset of BOO, 1 × 10(6) SPION-hMSCs were injected into the bladder wall. Serial T2-weighted MR images were taken immediately after transplantation of SPION-labeled human MSCs and at 4 weeks posttransplantation. T2-weighted MR images showed a clear hypointense signal induced by the SPION-labeled MSCs. While the expression of collagen and TGF-β protein increased after BOO, the expression of both returned to the original levels after MSC transplantation. Expression of HGF and c-met protein also increased in the group with MSC transplantation. Maximal voiding pressure and residual urine volume increased after BOO but they recovered after MSC transplantation. Human MSCs transplanted in rat BOO models inhibited the bladder fibrosis and mediated recovery of bladder dysfunction. Transplantation of MSC-based cell therapy could be a novel therapeutic strategy against bladder fibrosis in patients with bladder outlet obstruction.

A novel prostacyclin agonist protects against airway hyperresponsiveness and remodeling in mice

Airway remodeling in bronchial asthma results from chronic, persistent airway inflammation. The effects of the reversal of airway remodeling by drug interventions remain to be elucidated. We investigated the effects of ONO-1301, a novel prostacyclin agonist with thromboxane inhibitory activity, on the prevention and reversibility of airway remodeling in an experimental chronic asthma model. Mice sensitized and challenged to ovalbumin (OVA) three times a week for 5 consecutive weeks were administered ONO-1301 or vehicle twice a day from the fourth week of OVA challenges. Twenty-four hours after the final OVA challenge, airway hyperresponsiveness (AHR) was assessed, and bronchoalveolar lavage was performed. Lung specimens were excised for staining to detect goblet-cell metaplasia, airway smooth muscle, and submucosal fibrosis. Mice administered ONO-1301 showed limited increases in AHR compared with mice administered the vehicle. The histological findings of airway remodeling were improved in ONO-1301-treated mice compared with vehicle-treated mice. Presumably, these therapeutic effects of ONO-1301 are attributable to the up-regulation of production of hepatocyte growth factor (HGF) in lung tissue, because the neutralization of HGF by antibodies prevented the effects of ONO-1301 on AHR and airway remodeling. Mice administered ONO-1301 showed similar levels of AHR and airway remodeling as mice administered montelukast, a cysteinyl-leukotriene-1 receptor antagonist, and lower levels were observed in mice administered dexamethasone. These data suggest that ONO-1301 exerts the effect of reversing airway remodeling, at least in part through an elevation of HGF in the lungs, and may be effective as an anti-remodeling drug in the treatment of asthma.

Loss of c-Met accelerates development of liver fibrosis in response to CCl(4) exposure through deregulation of multiple molecular pathways

HGF/c-Met signaling plays a pivotal role in hepatocyte survival and tissue remodeling during liver regeneration. HGF treatment accelerates resolution of fibrosis in experimental animal models. Here, we utilized Met(fl/fl);Alb-Cre(+/-) conditional knockout mice and a carbon tetrachloride(CCl(4))-induced liver fibrosis model to formally address the role of c-Met signaling in hepatocytes in the context of chronic tissue injury. Histological changes during injury (4weeks) and healing phase (4weeks) were monitored by immunohistochemistry; expression levels of selected key fibrotic molecules were evaluated by western blotting, and time-dependent global transcriptomic changes were examined using a microarray platform. Loss of hepatocyte c-Met signaling altered hepatic microenvironment and aggravated hepatic fibrogenesis. Greater liver damage was associated with decreased hepatocyte proliferation, excessive stellate cell activation and rapid dystrophic calcification of necrotic areas. Global transcriptome analysis revealed a broad impact of c-Met on critical signaling pathways associated with fibrosis. Loss of hepatocyte c-Met caused a strong deregulation of chemotactic and inflammatory signaling (MCP-1, RANTES, Cxcl10) in addition to modulation of genes involved in reorganization of the cytoskeletal network (Actb, Tuba1a, Tuba8), intercellular communications and adhesion (Adam8, Icam1, Itgb2), control of cell proliferation (Ccng2, Csnk2a, Cdc6, cdk10), DNA damage and stress response (Rad9, Rad52, Ercc4, Gsta1 and 2, Jun). Our study demonstrates that deletion of c-Met receptor in hepatocytes results in pronounced changes in hepatic metabolism and microenvironment, and establishes an essential role for c-Met in maintaining the structural integrity and adaptive plasticity of the liver under adverse conditions.

Therapeutic potential of fibroblast growth factor-2 for hypertrophic scars: upregulation of MMP-1 and HGF expression

Although hypertrophic scars (HTSs) and keloids are challenging problems, their pathogenesis is not well understood, making therapy difficult. We showed that matrix metalloproteinase (MMP)-1 expression was downregulated in HTS compared with normal skin from the same patients, whereas type 1 and 3 collagen and transforming growth factor-β (TGF-β) were upregulated. These differences, however, were not seen in cultured fibroblasts, suggesting the involvement of microenvironmental factors in the pathogenesis of HTS. Fibroblast growth factor-2 (FGF-2) highly upregulated the expression of MMP-1 and hepatocyte growth factor (HGF) in both HTS-derived and control fibroblasts; the upregulation was reversed by extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) inhibitors. An animal study using human HTS tissue implanted into nude mice indicated that controlled-release FGF-2 resulted in significantly less weight and decreased hydroxyproline content in HTS. Degradation of collagen fibers in FGF-2-treated HTS was also confirmed histologically. Western blotting showed that FGF-2-treated HTS expressed significantly higher MMP-1 protein than control. Decreased MMP-1 expression may be an important transcriptional change in HTS, and its reversal as well as upregulation of HGF by FGF-2 could be a new therapeutic approach for HTS.

Hepatocyte growth factor in patients with coronary artery disease and its relation to periodontal condition

Hepatocyte growth factor (HGF) is an angiogenic, cardioprotective factor important for tissue and vascular repair. High levels of HGF are associated with chronic inflammatory diseases, such as coronary artery disease (CAD) and periodontitis, and are suggested as a marker of the ongoing atherosclerotic event in patients with CAD. Periodontal disease is more prevalent among patients with CAD than among healthy people. Recent studies indicate a reduced biological activity of HGF in different chronic inflammatory conditions. Biologically active HGF has high affinity to heparan sulfate proteoglycan (HSPG) on cell-membrane and extracellular matrix. The aim of the study was to investigate the serum concentration and the biological activity of HGF with ELISA and surface plasmon resonance (SPR), respectively, before and at various time points after percutaneous coronary intervention (PCI) in patients with CAD, and to examine the relationship with periodontal condition. The periodontal status of the CAD patients was examined, and the presence of P. gingivalis in periodontal pockets was analyzed with PCR. The HGF concentration was significantly higher, at all time-points, in patients with CAD compared to the age-matched controls (P< 0.001), but was independent of periodontal status. The HGF concentration and the affinity to HSPG adversely fluctuated over time, and the biological activity increased one month after intervention in patients without periodontitis. We conclude that elevated concentration of HGF but with reduced biological activity might indicate a chronic inflammatory profile in patients with CAD and periodontitis.

Expression of the c-Met oncogene by tumor cells predicts a favorable outcome in classical Hodgkin's lymphoma

BACKGROUND

The c-Met signaling pathway regulates a variety of biological processes, including proliferation, survival and migration. Deregulated c-Met activation has been implicated in the pathogenesis and prognosis of many human malignancies. We studied the function and prognostic significance of c-Met and hepatocyte growth factor protein expression in patients with classical Hodgkin's lymphoma.

DESIGN AND METHODS

Expression of c-Met and its ligand, hepatocyte growth factor, were determined by immunohistochemistry. Prognostic values were defined in cohorts of German and Dutch patients with classical Hodgkin's lymphoma. Functional studies were performed on Hodgkin's lymphoma cell lines.

RESULTS

Expression of c-Met was detected in the tumor cells of 52% (80/153) of the patients and expression of its ligand, hepatocyte growth factor, in 8% (10/121) of the patients. c-Met expression correlated with a 5-year freedom from tumor progression of 94%, whereas lack of expression correlated with a 5-year freedom from tumor progression of 73% (P<0.001) in the combined cohort. In multivariate analysis both c-Met (hazard ratio 5.0, 95% confidence interval 1.9-13.3, P<0.001) and stage (hazard ratio 2.8, 95% confidence interval 1.2-6.4, P=0.014) were independent predictors for freedom from tumor progression. In functional studies activation with hepatocyte growth factor did not affect cell growth, while the c-Met inhibitor SU11274 suppressed cell growth by inducing G2/M cell cycle arrest.

CONCLUSIONS

Although functional studies showed an oncogenic role of the hepatocyte growth factor/c-Met signaling pathway in cell cycle progression, expression of c-Met in tumor cells from patients with classical Hodgkin's lymphoma strongly correlated with a favorable prognosis in two independent cohorts.

Three dimensional cultures of rat liver cells using a natural self-assembling nanoscaffold in a clinically relevant bioreactor for bioartificial liver construction

Till date, no bioartificial liver (BAL) procedure has obtained FDA approval or widespread clinical acceptance, mainly because of multifactorial limitations such as the use of microscale or undefined biomaterials, indirect and lower oxygenation levels in liver cells, short-term undesirable functions, and a lack of 3D interaction of growth factor/cytokine signaling in liver cells. To overcome preclinical limitations, primary rat liver cells were cultured on a naturally self-assembling peptide nanoscaffold (SAPN) in a clinically relevant bioreactor for up to 35 days, under 3D interaction with suitable growth factors and cytokine signaling agents, alone or combination (e.g., Group I: EPO, Group II: Activin A, Group III: IL-6, Group IV: BMP-4, Group V: BMP4 + EPO, Group VI: EPO + IL-6, Group VII: BMP4 + IL-6, Group VIII: Activin A + EPO, Group IX: IL-6 + Activin A, Group X: Activin A + BMP4, Group XI: EPO + Activin A + BMP-4 + IL-6 + HGF, and Group XII: Control). Major liver specific functions such as albumin secretion, urea metabolism, ammonia detoxification, phase contrast microscopy, immunofluorescence of liver specific markers (Albumin and CYP3A1), mitochondrial status, glutamic oxaloacetic transaminase (GOT) activity, glutamic pyruvic transaminase (GPT) activity, and cell membrane stability by the lactate dehydrogenase (LDH) test were also examined and compared with the control over time. In addition, we examined the drug biotransformation potential of a diazepam drug in a two-compartment model (cell matrix phase and supernatant), which is clinically important. This present study demonstrates an optimized 3D signaling/scaffolding in a preclinical BAL model, as well as preclinical drug screening for better drug development.

Peroxisome proliferator-activated receptor-γ cross-regulation of signaling events implicated in liver fibrogenesis

Peroxisome proliferator-activated receptor-γ (PPARγ) is a nuclear receptor with transcriptional activity controlling multiple physical and pathological processes. Recently, PPARγ has been implicated in the pathogenesis of liver fibrosis. Its depleted expression has strong associations with the activation and transdifferentiation of hepatic stellate cells, the central event in liver fibrogenesis. Studies over the past decade demonstrate that PPARγ cross-regulates a number of signaling pathways mediated by growth factors and adipokines, and cellular events including apoptosis and senescence. These signaling and cellular events and their molecular interactions with PPARγ system are profoundly involved in liver fibrogenesis. We critically summarize these mechanistic insights into the PPARγ regulation in liver fibrogenesis based on the updated findings in this area. We conclude with a discussion of the impacts of these discoveries on the interpretation of liver fibrogenesis and their potential therapeutic implications. PPARγ activation could be a promising strategy for antifibrotic therapy.

Future directions in the evaluation of c-MET-driven malignancies

The c-MET (mesenchymal-epithelial transition factor) receptor tyrosine kinase is an exciting novel drug target in view of its key role in oncogenesis, as well as its association with disease prognosis in a number of malignancies. Several drugs targeting c-MET are currently showing promise in clinical trials and will hopefully validate positive observations from preclinical studies. The potential efficacy of these different therapeutic agents is expected to be influenced by the mechanism of aberrant hepatocyte growth factor (HGF)/c-MET signaling pathway activation in a particular cancer, but presents a promising strategy for cancer treatment either as a single agent or as part of a combination therapeutic approach. However, there is an ongoing need to improve and accelerate the transition of preclinical research into improved therapeutic strategies for patients with cancer. The main challenges facing the development of HGF/c-MET-targeted agents for cancer treatment include the discovery of rationally designed anticancer drugs and combination strategies, as well as the validation of predictive biomarkers. This paper discusses these issues, with a particular focus on future directions in the evaluation of c-MET-driven malignancies.

Association of hepatocyte growth factor promoter polymorphism with severity of interstitial lung disease in Japanese patients with systemic sclerosis

OBJECTIVE

To examine associations of single-nucleotide polymorphisms (SNPs) within genes for hepatocyte growth factor (HGF) and its receptor c-met with disease susceptibility and organ involvement in Japanese patients with systemic sclerosis (SSc).

METHODS

Four SNPs (HGF -1652 C/T, +44222 C/T, and +63555 G/T, and c-met -980 T/A) were analyzed in 159 SSc patients and 103 healthy control subjects with the use of a polymerase chain reaction-based assay. The influence of the HGF -1652 SNP on transcription activity was evaluated with a luciferase reporter assay and an electrophoretic mobility shift assay (EMSA).

RESULTS

There was no difference in the distribution of HGF/c-met SNPs between SSc patients and controls. HGF -1652 TT was found much more frequently in SSc patients with end-stage lung disease (ESLD) than in those without (41% versus 8%; P = 0.0004). This association was confirmed by a replication study involving a separate cohort of 155 SSc patients. Kaplan-Meyer analysis revealed that HGF -1652 TT carriers had a higher probability of developing ESLD than did CT or CC carriers. The HGF promoter carrying the HGF -1652 T allele had lower transcription activity than did the promoter carrying the C allele. EMSA showed the presence of a potential negative transcription regulator that binds specifically to the HGF promoter carrying a T allele at position -1652. Finally, TT carriers had a relative inability to increase circulating HGF levels even in the presence of advanced interstitial lung disease.

CONCLUSION

A SNP in the HGF promoter region may modulate the severity of interstitial lung disease by controlling the transcriptional efficiency of the HGF gene.

HVJ liposomes and HVJ envelope vectors

This protocol describes techniques for construction of fusion-mediated vectors based on inactivated HVJ (hemagglutinating virus of Japan; Sendai virus). HVJ liposomes are constructed by fusing liposomes containing DNA with inactivated HVJ. The HVJ envelope vector, a more simplified vector, incorporates DNA into inactivated HVJ particles without liposomes. Both vectors have many advantages. They can be used to introduce proteins, peptides, oligonucleotides (including antisense oligonucleotides, decoy oligonucleotides, and ribozymes), and short interfering RNA (siRNA), as well as plasmid DNA, into cultured cells in vitro and into organs in vivo. Fusion-mediated delivery avoids the degradation of therapeutic molecules before reaching the cytoplasm. Finally, repeated injection of the vector in vivo is not inhibited and even enhances the effects of the delivered molecules. These vectors have been used in many gene therapy experiments in animal models to address problems such as liver cirrhosis, hearing impairment, ischemic brain damage, peripheral arterial diseases, and cancers. This protocol describes methods for the preparation of HVJ liposomes and of HVJ envelope vectors and their use in delivery of plasmid DNA into various cells and tissues.

Hepatocyte growth factor (HGF) inhibits collagen I and IV synthesis in hepatic stellate cells by miRNA-29 induction

Background

In chronic liver disease, hepatic stellate cells (HSC) transdifferentiate into myofibroblasts, promoting extracellular matrix (ECM) synthesis and deposition. Stimulation of HSC by transforming growth factor-β (TGF-β) is a crucial event in liver fibrogenesis due to its impact on myofibroblastic transition and ECM induction. In contrast, hepatocyte growth factor (HGF), exerts antifibrotic activities. Recently, miR-29 has been reported to be involved in ECM synthesis. We therefore studied the influence of HGF and TGF-β on the miR-29 collagen axis in HSC.

Methodology

HSC, isolated from rats, were characterized for HGF and Met receptor expression by Real-Time PCR and Western blotting during culture induced myofibroblastic transition. Then, the levels of TGF-β, HGF, collagen-I and -IV mRNA, in addition to miR-29a and miR-29b were determined after HGF and TGF-β stimulation of HSC or after experimental fibrosis induced by bile-duct obstruction in rats. The interaction of miR-29 with 3′-untranslated mRNA regions (UTR) was analyzed by reporter assays. The repressive effect of miR-29 on collagen synthesis was studied in HSC treated with miR-29-mimicks by Real-Time PCR and immunoblotting.

Principal Findings

The 3′-UTR of the collagen-1 and −4 subtypes were identified to bind miR-29. Hence, miR-29a/b overexpression in HSC resulted in a marked reduction of collagen-I and -IV synthesis. Conversely, a decrease in miR-29 levels is observed during collagen accumulation upon experimental fibrosis, in vivo, and after TGF-β stimulation of HSC, in vitro. Finally, we show that during myofibroblastic transition and TGF-β exposure the HGF-receptor, Met, is upregulated in HSC. Thus, whereas TGF-β stimulation leads to a reduction in miR-29 expression and de-repression of collagen synthesis, stimulation with HGF was definitely associated with highly elevated miR-29 levels and markedly repressed collagen-I and -IV synthesis.

Conclusions

Upregulation of miRNA-29 by HGF and downregulation by TGF-β take part in the anti- or profibrogenic response of HSC, respectively.

Matrix metalloproteinase-13 promotes recovery from experimental liver cirrhosis in rats

OBJECTIVE

To evaluate the role of matrix metalloproteinase (MMP)-13 gene expression in the early phase of recovery from liver fibrosis/cirrhosis.

METHODS

Liver fibrosis was induced in male Wistar rats by administration of carbon tetrachloride (CCl(4)) for 10 weeks. Recombinant adenovirus-mediated human MMP-13 gene transfer (RAdMMP-13) was performed via the femoral vein on day 3 after the last CCl(4) injection. The role of MMP-13 in stably expressing cell lines was also analyzed.

RESULTS

Fibrous deposition in the liver was decreased in RAdMMP-13-injected rats by day 3 after gene transfer compared with empty vector RAd66-injected rats. Furthermore, MMP-2 and MMP-9 enzymatic activity was markedly enhanced in the liver of RAdMMP-13 injected rats. Hepatocyte growth factor (HGF) induction was also increased in RAdMMP-13 injected rats. In established stable HT-1080 cells transfected with MMP-13, HGF-α expression and MMP-2 and MMP-9 enzymatic activity were increased. The conversion of precursor HGF into mature HGF was also increased in the MMP-13 expressing cell lines.

CONCLUSION

Forced MMP-13 expression effectively accelerated recovery from liver cirrhosis via the effects of MMP-13-mediated HGF, MMP-2, and MMP-9 expression, which induced the degradation of collagen fibers and promoted hepatic regeneration.

Recombinant hepatocyte growth factor treatment in a canine model of congenital liver hypoplasia

BACKGROUND

Although the liver has a large regenerative capacity, in many hepatopathies, these repair mechanisms fail. The therapeutic potential of hepatocyte growth factor (HGF) has been proven in numerous toxin-induced liver failure models in rodents, but never in spontaneously occurring liver diseases in larger animal models.

AIM

The aim of this study was to induce liver growth in a hypoplastic liver by the administration of exogenous recombinant HGF. The natural hypoplastic liver model used is the canine congenital portosystemic shunt (CPSS) characterized by strongly reduced liver growth and function.

METHODS

Recombinant HGF (rHGF), 200 μg/kg, was given twice daily during 3 weeks by an intravenous injection in six dogs with CPSS. Liver volumes were determined by computed tomography before and at 1, 2, 3 and 7 weeks after the initiation of treatment. Portosystemic shunting was evaluated with an ammonia tolerance test and liver portal perfusion was quantified with scintigraphy. Simultaneously, blood parameters for liver function were assayed and liver biopsies were taken for histology, immunohistochemistry and gene-expression measurements.

RESULTS

During 3 weeks of HGF treatment, hepatocyte proliferation increased and an increase in liver volume up to 44% was seen, persisting in two dogs up to 4 weeks after the termination of treatment. Ki-67 expression, gene expression of E2F1 and CDC6, phosphorylated-c-MET and phosphorylated-ERK1/2 protein levels confirmed increased hepatocyte proliferation and HGF signalling. The aberrant portal perfusion did not change during treatment.

CONCLUSIONS

Transient in vivo liver growth is shown using CPPS as a naturally occurring large animal model, indicating the therapeutic potential of HGF in liver disease.

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.

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.

Differential expression of haptoglobin isoforms in chronic active hepatitis, cirrhosis and HCC related to HBV infection

The three main complications of hepatitis B virus (HBV) infection are chronic active hepatitis (CAH), liver cirrhosis, and hepatocellular carcinoma (HCC). The aim of this study was to identify differentially expressed serum proteins among the three liver complications in patients with HBV infection. Differentially expressed proteins have been shown to be potential biomarkers for disease diagnosis, prognosis and therapy guidance. Two-dimensional polyacrylamid gel electrophoresis (2DE) combined with liquid chromatography tandem mass spectrometry (LC-MS/MS) was performed on sera from CAH, cirrhosis and HCC patients with HBV infection, as well as those obtained from healthy individuals. Of 54 differentially expressed (≥1.5-fold and p<0.05) protein spots, 35 spots were identified by LC-MS/MS. The identified spots correlated to 13 proteins. The proteins included haptoglobolin α-2 and β isoforms, haptoglobin cleaved β isoforms, retinol-binding protein, transthyretin, ficolin, leucine-rich-α-2-glycoprotein, α-1-antitrypsin and clusterin. Of particular interest is the significant increase of haptoglobin α-2 isoforms in HCC patients compared to cirrhosis ones. In contrast, a significant decrease of the isoforms was noted among cirrhosis patients.

Novel therapy for myocardial infarction: can HGF/Met be beneficial?

Myocardial infarction (MI) is a leading cause of hospitalization worldwide. A recently developed strategy to improve the management of MI is based on the use of growth factors which are able to enhance the intrinsic capacity of the heart to repair itself or regenerate after damage. Among others, hepatocyte growth factor (HGF) has been proposed as a modulator of cardiac repair of damage due to the pleiotropic effects elicited by Met receptor stimulation. In this review we describe the mechanistic basis for autocrine and paracrine protection of HGF in the injured heart. We also analyse the role of HGF/Met in stem cell maintenance and in stem cell therapies for MI. Finally, we summarize the most significant results on the use of HGF in experimental models of heart injury and discuss the potential of the molecule for treating ischaemic heart disease in humans.

Hepatocyte growth factor incorporated chitosan nanoparticles augment the differentiation of stem cell into hepatocytes for the recovery of liver cirrhosis in mice

Background

Short half-life and low levels of growth factors in the niche of injured microenvironment necessitates the exogenous and sustainable delivery of growth factors along with stem cells to augment the regeneration of injured tissues.

Methods

Here, recombinant human hepatocyte growth factor (HGF) was incorporated into chitosan nanoparticles (CNP) by ionic gelation method and studied for its morphological and physiological characteristics. Cirrhotic mice received either hematopoietic stem cells (HSC) or mesenchymal stemcells (MSC) with or without HGF incorporated chitosan nanoparticles (HGF-CNP) and saline as control. Biochemical, histological, immunostaining and gene expression assays were carried out using serum and liver tissue samples. One way analysis of variance was used for statics application

Results

Serum levels of selected liver protein and enzymes were significantly increased in the combination of MSC and HGF-CNP (MSC+HGF-CNP) treated group. Immunopositive staining for albumin (Alb) and cytokeratin 18 (CK18), and reverse transcription-polymerase chain reaction (RT-PCR) for Alb, alpha fetoprotein (AFP), CK18, cytokeratin 19 (CK19) ascertained that MSC-HGF-CNP treatment could be an effective combination to repopulate liver parenchymal cells in the liver cirrhosis. Zymogram and western blotting for matrix metalloproteinases 2 and 9 (MMP2 and MMP9) revealed that MMP2 actively involved in the fibrolysis of cirrhotic tissue. Immunostaining for alpha smooth muscle actin (αSMA) and type I collagen showed decreased expression in the MSC+HGF-CNP treatment. These results indicated that HGF-CNP enhanced the differentiation of stem cells into hepatocytes and supported the reversal of fibrolysis of extracellular matrix (ECM).

Conclusion

Bone marrow stem cells were isolated, characterized and transplanted in mice model. Biodegradable biopolymeric nanoparticles were prepared with the pleotrophic protein molecule and it worked well for the differentiation of stem cells, especially mesenchymal phenotypic cells. Transplantation of bone marrow MSC in combination with HGF-CNP could be an ideal approach for the treatment of liver cirrhosis.

Cellular Injury of Cardiomyocytes during Hepatocyte Growth Factor Gene Transfection with Ultrasound-Triggered Bubble Liposome Destruction

We transfected naked HGF plasmid DNA into cultured cardiomyocytes using a sonoporation method consisting of ultrasound-triggered bubble liposome destruction. We examined the effects on transfection efficiency of three concentrations of bubble liposome (1 × 10⁶, 1 × 10⁷, 1 × 10⁸/mL), three concentrations of HGF DNA (60, 120, 180 μg/mL), two insonification times (30, 60 sec), and three incubation times (15, 60, 120 min). We found that low concentrations of bubble liposome and low concentrations of DNA provided the largest amount of the HGF protein expression by the sonoporated cardiomyocytes. Variation of insonification and incubation times did not affect the amount of product. Following insonification, cardiomyocytes showed cellular injury, as determined by a dye exclusion test. The extent of injury was most severe with the highest concentration of bubble liposome. In conclusion, there are some trade-offs between gene transfection efficiency and cellular injury using ultrasound-triggered bubble liposome destruction as a method for gene transfection.

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.

CXCL5 plasma levels decrease in patients with chronic liver disease

BACKGROUND AND AIMS

CXCL5 (chemokine [C-X-C motif] ligand 5, also known as epithelial neutrophil-activating peptide 78 [ENA78]) belongs to the CXC chemokine family and has been shown to have promitotic effects on hepatocytes. The aim of our study was to assess CXCL5 plasma levels in patients with chronic liver disease.

METHODS

CXCL5 plasma levels were measured in 111 patients with chronic liver disease and 98 healthy controls. The gene expression of CXCL5 and its main receptor, CXC receptor-2, were also determined in liver biopsies from 46 patients.

RESULTS

CXCL5 levels were correlated with clinical presentation, laboratory parameters, and liver histology. Plasma CXCL5 levels in patients with liver cirrhosis were lower than those in healthy controls, and correlated with hepatic biosynthetic capacity, Child-Pugh and model for end-stage liver disease scores. Patients with hepatic necroinflammation and fibrosis on liver histology showed lower plasma CXCL5 levels. In patients with typical clinical complications of cirrhosis, CXCL5 levels were found to be decreased. Intrahepatically, CXCL5 expression was increased in patients with advanced fibrosis and cirrhosis. The isolation of different cellular compartments from mouse livers suggested that hepatic stellate cells and sinusoidal endothelial cells are the main sources of hepatic CXCL5.

CONCLUSIONS

Plasma CXCL5 levels are lower in patients with chronic liver disease, suggesting that CXCL5 might be involved in the pathogenesis of chronic liver disease. CXCL5 could serve as an additional biomarker for hepatic necroinflammation and fibrosis.

Transplanted human amniotic membrane-derived mesenchymal stem cells ameliorate carbon tetrachloride-induced liver cirrhosis in mouse

Background

Human amniotic membrane-derived mesenchymal stem cells (hAMCs) have the potential to reduce heart and lung fibrosis, but whether could reduce liver fibrosis remains largely unknown.

Methodology/Principal Findings

Hepatic cirrhosis model was established by infusion of CCl₄ (1 ml/kg body weight twice a week for 8 weeks) in immunocompetent C57Bl/6J mice. hAMCs, isolated from term delivered placenta, were infused into the spleen at 4 weeks after mice were challenged with CCl₄. Control mice received only saline infusion. Animals were sacrificed at 4 weeks post-transplantation. Blood analysis was performed to evaluate alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Histological analysis of the livers for fibrosis, hepatic stellate cells activation, hepatocyte apoptosis, proliferation and senescence were performed. The donor cell engraftment was assessed using immunofluorescence and polymerase chain reaction. The areas of hepatic fibrosis were reduced (6.2%±2.1 vs. control 9.6%±1.7, p<0.05) and liver function parameters (ALT 539.6±545.1 U/dl, AST 589.7±342.8 U/dl,vs. control ALT 139.1±138.3 U/dl, p<0.05 and AST 212.3±110.7 U/dl, p<0.01) were markedly ameliorated in the hAMCs group compared to control group. The transplantation of hAMCs into liver-fibrotic mice suppressed activation of hepatic stellate cells, decreased hepatocyte apoptosis and promoted liver regeneration. More interesting, hepatocyte senescence was depressed significantly in hAMCs group compared to control group. Immunofluorescence and polymerase chain reaction revealed that hAMCs engraftment into host livers and expressed the hepatocyte-specific markers, human albumin and α-fetoproteinran.

Conclusions/Significance

The transplantation of hAMCs significantly decreased the fibrosis formation and progression of CCl₄-induced cirrhosis, providing a new approach for the treatment of fibrotic liver disease.

Stem cells and hepatocellular carcinoma

Stem cells are a class of special embryonic or adult cells that are able to self-renew and undergo multi-directional differentiation. Studies have shown that stem cells have selective tropism toward tumor tissue. Previous studies have shown that hepatic stem cells play an important role in hepatocarcinogenesis by participating in regulation of cell growth and differentiation. However, some other studies demonstrated that stem cells could inhibit cell growth in hepatocellular carcinoma. Elucidation of relationship between stem cells and hepatocellular carcinoma could provide new clues to the pathogenesis of hepatocellular carcinoma and help develop new therapeutic strategies for the disease.

MET signalling: principles and functions in development, organ regeneration and cancer

The MET tyrosine kinase receptor (also known as the HGF receptor) promotes tissue remodelling, which underlies developmental morphogenesis, wound repair, organ homeostasis and cancer metastasis, by integrating growth, survival and migration cues in response to environmental stimuli or cell-autonomous perturbations. The versatility of MET-mediated biological responses is sustained by qualitative and quantitative signal modulation. Qualitative mechanisms include the engagement of dedicated signal transducers and the subcellular compartmentalization of MET signalling pathways, whereas quantitative regulation involves MET partnering with adaptor amplifiers or being degraded through the shedding of its extracellular domain or through intracellular ubiquitylation. Controlled activation of MET signalling can be exploited in regenerative medicine, whereas MET inhibition might slow down tumour progression.

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.

Attenuation of N-nitrosodiethylamine-induced liver fibrosis by high-molecular-weight fucoidan derived from Cladosiphon okamuranus

BACKGROUND AND AIM

Liver fibrosis is closely associated with the progression of various chronic liver diseases. Fucoidan exhibits different biological properties such as anti-inflammatory, anti-oxidant and anti-fibrotic activities. The aim of this study was to determine whether oral fucoidan administration inhibits N-nitrosodiethylamine (DEN)-induced liver fibrosis.

METHODS

Liver fibrosis was induced in rats by injecting DEN (50 mg/kg). Rats were given 2% of crude fucoidan solution or 2% of high-molecular-weight (HMW) fucoidan solution. They were divided into a crude fucoidan group, an HMW fucoidan group, a DEN alone group, a DEN + crude fucoidan group, a DEN + HMW fucoidan group and a control group.

RESULTS

Liver fibrosis and hepatic hydroxyproline levels were significantly more decreased in the DEN + HMW fucoidan group than in the DEN-alone group. Anti-fibrogenesis was unremarkable in the DEN + crude fucoidan group. Hepatic messenger RNA levels and immunohistochemistry of transforming growth factor beta 1 were markedly increased by DEN. This increase was attenuated by HMW fucoidan. Hepatic chemokine ligand 12 expression was increased by DEN. This increase was suppressed by HMW fucoidan. HMW fucoidan significantly decreased the DEN-induced malondialdehyde levels. Also, fucoidan markedly increased metallothionein expression in the liver. Fucoidan was clearly observed in the liver by immunohistochemical staining in HMW fucoidan-treated rats, while it was faintly stained in the livers of crude fucoidan-treated rats.

CONCLUSION

These findings suggest that the HMW fucoidan treatment causes anti-fibrogenesis in DEN-induced liver cirrhosis through the downregulation of transforming growth factor beta 1 and chemokine ligand 12 expressions, and that scavenging lipid peroxidation is well-incorporated in the liver.

A tandem repeat of a fragment of Listeria monocytogenes internalin B protein induces cell survival and proliferation

Hepatocyte growth factor (HGF) is critical for tissue homeostasis and repair in many organs including the lung, heart, kidney, liver, nervous system, and skin. HGF is a heterodimeric protein containing 20 disulfide bonds distributed among an amino-terminal hairpin, four kringle domains, and a serine protease-like domain. Due to its complex structure, recombinant production of HGF in prokaryotes requires denaturation and refolding, processes that are impractical for large-scale manufacture. Thus, pharmaceutical quantities of HGF are not available despite its potential applications. A fragment of the Listeria monocytogenes internalin B protein from amino acids 36-321 (InlB₃₆₋₃₂₁) was demonstrated to bind to and partially activate the HGF receptor Met. InlB₃₆₋₃₂₁ has a stable β-sheet structure and is easily produced in its native conformation by Escherichia coli. We cloned InlB₃₆₋₃₂₁ (1×InlB₃₆₋₃₂₁) and engineered a head-to-tail repeat of InlB₃₆₋₃₂₁ with a linker peptide (2×InlB₃₆₋₃₂₁); 1×InlB₃₆₋₃₂₁ and 2×InlB₃₆₋₃₂₁ were purified from E. coli. Both 1× and 2×InlB₃₆₋₃₂₁ activated the Met tyrosine kinase. We subsequently compared signal transduction of the two proteins in primary lung endothelial cells. 2×InlB₃₆₋₃₂₁ activated ERK1/2, STAT3, and phosphatidylinositol 3-kinase/Akt pathways, whereas 1×InlB₃₆₋₃₂₁ activated only STAT3 and ERK1/2. The 2×InlB₃₆₋₃₂₁ promoted improved motility compared with 1×InlB₃₆₋₃₂₁ and additionally stimulated proliferation equivalent to full-length HGF. Both the 1× and 2×InlB₃₆₋₃₂₁ prevented apoptosis by the profibrotic peptide angiotensin II in cell culture and ex vivo lung slice cultures. The ease of large-scale production and capacity of 2×InlB₃₆₋₃₂₁ to mimic HGF make it a potential candidate as a pharmaceutical agent for tissue repair.