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

Hepatocyte growth factor/c-met promotes proliferation, suppresses apoptosis, and improves matrix metabolism in rabbit nucleus pulposus cells in vitro

The etiology of intervertebral disc (IVD) degeneration is closely related to apoptosis and extracellular matrix degradation in nucleus pulposus (NP) cells. These defects in NP cells are induced by excessive external stressors such as reactive oxygen species (ROS) and inflammatory cytokines. Recently, hepatocyte growth factor (HGF) has been shown to repair damage in various diseases through anti-apoptotic and anti-inflammatory activity. In this study, we investigated the effects of HGF on NP cell abnormality caused by ROS and inflammatory cytokines by using primary NP cells isolated from rabbit IVD. HGF significantly enhanced the proliferation of NP cells. Apoptosis of NP cells induced by H2 O2 or TNF-α was significantly inhibited by HGF. Induction of mRNA expression of the inflammation mediators cyclooxygenase-2 and matrix metalloproteinase-3 and -9 by TNF-α was significantly suppressed by HGF treatment. Expression of c-Met, a specific receptor for HGF, was confirmed in NP cells and was increased by TNF-α, suggesting that inflammatory cytokines increase sensitivity to HGF. These findings demonstrate that activation of HGF/c-Met signaling suppresses damage caused by ROS and inflammation in NP cells through multiple pathways. We further suggest the clinical potential of HGF for counteracting IVD degradation involved in NP cell abnormalities.

Recent Progress in Therapeutic Strategies for Ischemic Stroke

Possible strategies for treating stroke include neuroprotection in the acute phase of cerebral ischemia and stem cell therapy in the chronic phase of cerebral ischemia. Previously, we have studied the temporal and spatial expression patterns of c-fos, hypoxia inducible factor-1α (HIF-1α), heat shock protein 70 (HSP70), and annexin V after 90 min of transient middle cerebral occlusion in rats and concluded that there is a time window for neuroprotection from 12 to 48 h after ischemia. In addition, we have estimated the neuroprotective effect of glial cell line-derived neurotrophic factor (GDNF) by injecting Sendai viral vector containing the GDNF gene into the postischemic brain. This Sendai virus-mediated gene transfer of GDNF showed a significant neuroprotective effect in the ischemic brain. Additionally, we have administered GDNF and hepatocyte growth factor (HGF) protein into the postischemic rat brain and estimated the infarct size and antiapoptotic and antiautophagic effects. GDNF and HGF significantly reduced infarct size, the number of microtubule-associated protein 1 light chain 3 (LC3)-positive cells, and the number of terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick-end labeling (TUNEL)-positive cells, indicating that GDNF and HGF were greatly associated with not only the antiapoptotic effect but also the antiautophagic effects. Finally, we have previously transplanted undifferentiated iPSCs into the ipsilateral striatum and cortex at 24 h after cerebral ischemia. Histological analysis was performed at 14 and 28 days after cell transplantation, and we found that iPSCs could supply a great number of doublecortin-positive neuroblasts but also formed tridermal teratoma in the ischemic brain. Our results suggest that iPSCs have a potential to provide neural cells after ischemic brain injury if tumorigenesis is properly controlled. In the future, we will combine these strategies to develop more effective therapies for the treatment of strokes.

Importance of osteoprotegrin and receptor activator of nuclear factor κB in breast cancer response to hepatocyte growth factor and the bone microenvironment in vitro

Osteoprotegrin (OPG), receptor activator of nuclear factor κB (RANK) and RANK ligand (RANKL) are signal transducers which have pleiotropic actions. Each tumour necrosis factor receptor superfamily member has unique structural attributes which directly couples them to signalling pathways involved in cell proliferation, differentiation and survival. Previous studies have clinically linked OPG, RANK and RANKL to increasing tumour burden, metastatic bone involvement and estrogen status. This study aimed to establish the potential implications of targeting endogenously produced OPG and RANK in the osteotropic breast cancer cell line MDA-MB‑231 in vitro. Subsequently this study also aimed to explore the potential links between these molecules with regards to hepatocyte growth factor (HGF) signalling and extracted bone proteins (BME). OPG and RANK expression was successfully suppressed using hammerhead ribozyme technology. Subsequently effects were explored in MDA-MB‑231 cell proliferation, matrix adhesion, migration and invasion in vitro function assays. Reduced OPG expression resulted in increased breast cancer cell migration and invasion. These increases, particularly invasion, appeared to however be reduced under the influence of the exogenous stimuli (HGF and BME). In contrast, suppression of RANK in MDA-MB‑231 breast cancer cells resulted in decreased cancer cell proliferation, matrix-adhesion, motility and invasion with little cumulative effect being noted after the addition of exogenous stimuli. The complexity of the bone environment underpins the vast number of soluble factors and signalling pathways which can influence osteotropic cancer behaviour and progression. Further work into elucidating all the pathways affected could potentially lead to better identification of those patients most at risk.

Roles of c-Met and RON kinases in tumor progression and their potential as therapeutic targets

c-Met and receptor originated from nantes (RON) are structurally related transmembrane phosphotyrosine kinase receptors. c-Met and RON show increased expression or activity in a variety of tumors leading to tumor progression and may play a role in acquired resistance to therapy. Although often co-expressed, the distinct functional roles of c-Met and RON are not fully understood. c-Met and RON form both activated homodimers and heterodimers with themselves and other families of phosphotyrosine kinase receptors. Inhibitors for c-Met and RON including small molecular weigh kinase inhibitors and neutralizing antibodies are in pre-clinical investigation and clinical trials. Several of the tyrosine kinase inhibitors have activity against both c-Met and RON kinases whereas the antibodies generally are target specific. As with many targeted agents used to treat solid tumors, it is likely that c-Met/RON inhibitors will have greater benefit when used in combination with chemotherapy or other targeted agents. A careful analysis of c-Met/RON expression or activity and a better elucidation of how they influence cell signaling will be useful in predicting which tumors respond best to these inhibitors as well as determining which agents can be used with these inhibitors for combined therapy.

Cellular and molecular mechanisms of HGF/Met in the cardiovascular system

Met tyrosine kinase receptor, also known as c-Met, is the HGF (hepatocyte growth factor) receptor. The HGF/Met pathway has a prominent role in cardiovascular remodelling after tissue injury. The present review provides a synopsis of the cellular and molecular mechanisms underlying the effects of HGF/Met in the heart and blood vessels. In vivo, HGF/Met function is particularly important for the protection of the heart in response to both acute and chronic insults, including ischaemic injury and doxorubicin-induced cardiotoxicity. Accordingly, conditional deletion of Met in cardiomyocytes results in impaired organ defence against oxidative stress. After ischaemic injury, activation of Met provides strong anti-apoptotic stimuli for cardiomyocytes through PI3K (phosphoinositide 3-kinase)/Akt and MAPK (mitogen-activated protein kinase) cascades. Recently, we found that HGF/Met is also important for autophagy regulation in cardiomyocytes via the mTOR (mammalian target of rapamycin) pathway. HGF/Met induces proliferation and migration of endothelial cells through Rac1 (Ras-related C3 botulinum toxin substrate 1) activation. In fibroblasts, HGF/Met antagonizes the actions of TGFβ1 (transforming growth factor β1) and AngII (angiotensin II), thus preventing fibrosis. Moreover, HGF/Met influences the inflammatory response of macrophages and the immune response of dendritic cells, indicating its protective function against atherosclerotic and autoimmune diseases. The HGF/Met axis also plays an important role in regulating self-renewal and myocardial regeneration through the enhancement of cardiac progenitor cells. HGF/Met has beneficial effects against myocardial infarction and endothelial dysfunction: the cellular and molecular mechanisms underlying repair function in the heart and blood vessels are common and include pro-angiogenic, anti-inflammatory and anti-fibrotic actions. Thus administration of HGF or HGF mimetics may represent a promising therapeutic agent for the treatment of both coronary and peripheral artery disease.

Effects of SNPs and alternative splicing within HGF gene on its expression patterns in Qinchuan cattle

Background

Identification of genetic variants, including SNPs (Single Nucleotide Polymorphisms), CNVs (Copy Number Variations) and alternative splicing, within functional genes has received increasing attention in animal science research. HGF (Hepatocyte Growth Factor) is a very important growth factor that works as a mitogen or a morphogen during tissue growth, development and regeneration. However, to date, the functions of genetic variants within the bovine HGF gene, particularly their effects on mRNA expression, have not been determined well.

Results

The present study aimed to perform association analysis between genetic variants and mRNA expression for the bovine HGF gene in Qinchuan cattle using various strategies, including PCR-RFLP (Restriction Fragment Length Polymorphism), qPCR (Quantitative Real-time quantitative PCR), TA cloning, DNA sequencing and bioinformatics analysis. A total of five SNPs were identified and only SV1 locus significantly affected HGF mRNA expression in fetal skeletal muscle (P < 0.05). Heterozygous genotype individuals showed significantly higher HGF expression (P < 0.05), which was significantly greater in the “CTCCAGGGTT” combined genotype than that in the “CCCCGGGGTT” combined genotype (P < 0.05). In addition, two alternative splicing variations, HGF-W and HGF-M, were identified, which resulted from alternative 3′ splice sites of exon 5, and HGF-W showed higher mRNA levels than HGF-M in all tissues.

Conclusion

In summary, genetic variations within the HGF gene affected mRNA expression. These findings provide new insight into the molecular characteristics and functions of bovine HGF.

Overexpression of hepatocyte growth factor in SBMA model mice has an additive effect on combination therapy with castration

Spinal and bulbar muscular atrophy (SBMA) is an inherited motor neuron disease caused by the expansion of a polyglutamine (polyQ)-encoding tract within the androgen receptor (AR) gene. The pathologic features of SBMA are motor neuron loss in the spinal cord and brainstem and diffuse nuclear accumulation and nuclear inclusions of mutant AR in residual motor neurons and certain visceral organs. Hepatocyte growth factor (HGF) is a polypeptide growth factor which has neuroprotective properties. To investigate whether HGF overexpression can affect disease progression in a mouse model of SBMA, we crossed SBMA transgenic model mice expressing an AR gene with an expanded CAG repeat with mice overexpressing HGF. Here, we report that high expression of HGF induces Akt phosphorylation and modestly ameliorated motor symptoms in an SBMA transgenic mouse model treated with or without castration. These findings suggest that HGF overexpression can provide a potential therapeutic avenue as a combination therapy with disease-modifying therapies in SBMA.

Targeted delivery of HGF to the skeletal muscle improves glucose homeostasis in diet-induced obese mice

Hepatocyte growth factor (HGF) is a cytokine that increases glucose transport ex vivo in skeletal muscle. The aim of this work was to decipher the impact of whether conditional overexpression of HGF in vivo could improve glucose homeostasis and insulin sensitivity in mouse skeletal muscle. Following tetracyclin administration, muscle HGF levels were augmented threefold in transgenic mice (SK-HGF) compared to control mice without altering plasma HGF levels. In conditions of normal diet, SK-HGF mice showed no differences in body weight, plasma triglycerides, blood glucose, plasma insulin and glucose tolerance compared to control mice. Importantly, obese SK-HGF mice exhibited improved whole-body glucose tolerance independently of changes in body weight or plasma triglyceride levels compared to control mice. This effect on glucose homeostasis was associated with significantly higher (∼80%) levels of phosphorylated protein kinase B in muscles from SK-HGF mice compared to control mice. In conclusion, muscle expression of HGF counteracts obesity-mediated muscle insulin resistance and improves glucose tolerance in mice.

Decreased Phosphorylated Protein Kinase B (Akt) in Individuals with Autism Associated with High Epidermal Growth Factor Receptor (EGFR) and Low Gamma-Aminobutyric Acid (GABA)

Dysregulation of the PI3K/AKT/mammalian target of rapamycin (mTOR) pathway could contribute to the pathogenesis of autism spectrum disorders. In this study, phosphorylated Akt concentration was measured in 37 autistic children and 12, gender and age similar neurotypical, controls using an enzyme-linked immunosorbent assay. Akt levels were compared to biomarkers known to be associated with epidermal growth factor receptor (EGFR) and c-Met (hepatocyte growth factor (HGF) receptor) pathways and severity levels of 19 autism-related symptoms. We found phosphorylated Akt levels significantly lower in autistic children and low Akt levels correlated with high EGFR and HGF and low gamma-aminobutyric acid, but not other biomarkers. Low Akt levels also correlated significantly with increased severity of receptive language, conversational language, hypotonia, rocking and pacing, and stimming, These results suggest a relationship between decreased phosphorylated Akt and selected symptom severity in autistic children and support the suggestion that the AKT pathways may be associated with the etiology of autism.

Hepatocyte Growth Factor from a Clinical Perspective: A Pancreatic Cancer Challenge

Pancreatic cancer is the fourth leading cause of cancer-related deaths in the United States and incidence rates are rising. Both detection and treatment options for pancreatic cancer are limited, providing a less than 5% five-year survival advantage. The need for new biomarkers for early detection and treatment of pancreatic cancer demands the efficient translation of bench knowledge to provide clinical benefit. One source of therapeutic resistance is the pancreatic tumor microenvironment, which is characterized by desmoplasia and hypoxia making it less conducive to current therapies. A major factor regulating desmoplasia and subsequently promoting chemoresistance in pancreatic cancer is hepatocyte growth factor (HGF), the sole ligand for c-MET (mesenchymal-epithelial transition), an epithelial tyrosine kinase receptor. Binding of HGF to c-MET leads to receptor dimerization and autophosphorylation resulting in the activation of multiple cellular processes that support cancer progression. Inhibiting activation of c-MET in cancer cells, in combination with other approaches for reducing desmoplasia in the tumor microenvironment, might significantly improve the success of chemotherapy. Therefore, HGF makes a potent novel target for developing therapeutic strategies in combination with existing drugs for treating pancreatic adenocarcinoma. This review provides a comprehensive analysis of HGF and its promising potential as a chemotherapeutic target for pancreatic cancer.

The Effect of Granulocyte Colony-Stimulating Factor on Immune-Modulatory Cytokines in the Bone Marrow Microenvironment and Mesenchymal Stem Cells of Healthy Donors

Granulocyte colony stimulating factor (G-CSF) is sometimes administered to donors before bone marrow (BM) harvest. G-CSF-primed (G-BM) and unprimed BM (U-BM)-derived mesenchymal stem cells (MSC) were obtained from 16 healthy donors and were expanded in vitro. Their proliferative characteristics, morphology, and differentiation capacity were examined. Supernatants of the second passage of MSCs were evaluated for transforming growth factor β1, hepatocyte growth factor, and prostaglandin E2 (PGE2) levels and compared with controls. The analyses of cytokines in the G-BM- and U-BM-derived MSCs supernatants revealed that PGE2 levels were significantly lower in the G-CSF-primed samples. These cytokines were also measured in BM plasma. The level of hepatocyte growth factor in G-BM plasma was significantly increased. The current study is the first to show the effects of G-CSF on the BM microenvironment of healthy human donors. The preliminary data suggest that G-BM- and U-BM-derived MSCs have similar morphologic/phenotypic properties and differentiation capacity but differ in their secretory capacity. Significant changes in cytokine levels of BM plasma in G-CSF-primed donors were also demonstrated. These findings suggest that BM MSCs and changes in the BM microenvironment may contribute to the effects of G-CSF on inflammation and immunomodulation.

Trans-ethnic meta-analysis identifies common and rare variants associated with hepatocyte growth factor levels in the Multi-Ethnic Study of Atherosclerosis (MESA)

Hepatocyte growth factor (HGF) is a mesenchyme-derived pleiotropic factor that regulates cell growth, motility, mitogenesis, and morphogenesis in a variety of cells, and increased serum levels of HGF have been linked to a number of clinical and subclinical cardiovascular disease phenotypes. However, little is currently known regarding which genetic factors influence HGF levels, despite evidence of substantial genetic contributions to HGF variation. Based upon ethnicity-stratified single-variant association analysis and trans-ethnic meta-analysis of 6201 participants of the Multi-Ethnic Study of Atherosclerosis (MESA), we discovered five statistically significant common and low-frequency variants: HGF missense polymorphism rs5745687 (p.E299K) as well as four variants (rs16844364, rs4690098, rs114303452, rs3748034) within or in proximity to HGFAC. We also identified two significant ethnicity-specific gene-level associations (A1BG in African Americans; FASN in Chinese Americans) based upon low-frequency/rare variants, while meta-analysis of gene-level results identified a significant association for HGFAC. However, identified single-variant associations explained modest proportions of the total trait variation and were not significantly associated with coronary artery calcium or coronary heart disease. Our findings indicate that genetic factors influencing circulating HGF levels may be complex and ethnically diverse.

Recombinant human hepatocyte growth factor (HGF), but not rat HGF, elicits glomerular injury and albuminuria in normal rats via an immune complex-dependent mechanism

1. Hepatocyte growth factor (HGF) has the therapeutic potential to improve renal fibrosis and proteinuria in rodents with chronic kidney disease. In contrast, long-term administration of human HGF to normal rats reportedly elicits proteinuria. Thus, the role of HGF during proteinuria remains contentious. The aim of the present study was to demonstrate that human HGF is antigenic to rodents and that immune complex formation causes proteinuria. 2. We administered either human or rat HGF to normal rats for 28 days. Albuminuria was evaluated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The renal phenotypes of the two HGF treatments were examined using histological techniques. 3. Administration of human HGF (1 mg/kg per day, i.v.) to rats led to severe albuminuria and glomerular hypertrophy in association with increased blood levels of anti-human HGF IgG and IgG deposition in mesangial areas. Furthermore, an immune complex between human HGF and anti-human HGF IgG stimulated the production of proteinuric cytokines (including transforming growth factor-β) in rat cultured mesangial cells. In contrast, treatment of healthy rats with rat HGF for 4 weeks caused neither mesangial IgG deposition nor elevated anti-HGF IgG in the blood. Overall, rat HGF did not provoke albuminuria. 4. We conclude that human HGF produces pseudotoxic effects in normal rat kidneys via an immune complex-mediated pathway, whereas syngenic HGF is safe due to less deposition of glomerular IgG. Our results affirm the safety of the repeated use of syngenic HGF for the treatment of chronic organ diseases, such as renal fibrosis and liver cirrhosis.

The low levels of circulating hepatocyte growth factor in nephrolithiasis cases: independent from gene polymorphism

Environmental and genetic factors are important in development of nephrolithiasis. In a recent study, it has been demonstrated that hepatocyte growth factor (HGF) has an anti-apoptotic effect and thus can reduce the adhesion of calcium oxalate monohydrate crystals to renal epithelial cells. The aim of this study was to evaluate the HGF serum levels and its two gene polymorphisms and possible association of the two in patients with nephrolithiasis. One hundred and five patients with nephrolithiasis and 70 healthy volunteers with similar demographic features were included in this study. Serum HGF levels were measured, and HGF intron 13 C>A (in 102 stone patients and 68 healthy subjects) and intron 14 T>C (in 99 stone patients and 56 healthy subjects) polymorphisms were determined using real-time polymerase chain reaction with TaqMan allelic discrimination method. There were no statistically significant differences in HGF intron 13 C>A and intron 14 T>C polymorphisms between the control and patient groups (X (2) = 1.72 df = 2; p = 0.42, and X (2) = 0.68 df = 2; p = 0.71, respectively). Mean serum HGF concentration was significantly lower in the stone disease patients than in the control subjects (1.05 ± 0.63 pg/mL and 1.35 ± 0.58 ng/mL respectively, p = 0.0001). When allele distribution frequency between stone patients and healthy subjects was compared, there were no significant differences in intron 13 and intron 14 allele distributions between two groups (p = 0.43 and p = 0.44, respectively). It may be concluded from the findings that decrease in HGF levels may play a role in renal stone formation, independent from gene polymorphisms.

Increased c-Met phosphorylation is related to keloid pathogenesis: implications for the biological behaviour of keloid fibroblasts

Keloid is induced by a pathological wound healing response, and hepatocyte growth factor (HGF) is known to be involved in tissue repair via the activation of its primary receptor, c-Met. We aimed to investigate whether c-Met activation is implicated in keloid pathogenesis. HGF, c-Met, phosphorylated c-Met (p-Met), Ki-67, collagen I protein, and MET gene expression were detected in five normal skin and 30 keloid tissues by immunohistochemistry and quantitative real-time polymerase chain reaction analysis, respectively. The influence of p-Met expression on the biological behaviour of keloid fibroblasts was further investigated with regard to cell proliferation, motility, invasiveness, collagen I expression, and intracellular signaling in vitro. p-Met protein and MET gene expression but not HGF or c-Met protein expression showed significant increases in keloid tissues than dermal layer of normal skin tissues. In keloid tissues, p-Met expression was significantly associated with keloid size, Ki-67 and collagen I expression. Moreover, p-Met expression was also related to proliferation, migration, invasiveness, collagen I expression and activation of AKT and Erk in keloid fibroblasts in vitro. c-Met activation may have a strong influence on keloid pathogenesis, and it can be investigated further as a potential molecular target for keloid therapy.

c-MET receptor tyrosine kinase as a molecular target in advanced hepatocellular carcinoma

c-MET is the membrane receptor for hepatocyte growth factor (HGF), also known as scatter factor or tumor cytotoxic factor, a mitogenic growth factor for hepatocytes. HGF is mainly produced by cells of mesenchymal origin and it mainly acts on neighboring epidermal and endothelial cells, regulating epithelial growth and morphogenesis. HGF/MET signaling has been identified among the drivers of tumorigenesis in human cancers. As such, c-MET is a recognized druggable target, and against it, targeted agents are currently under clinical investigation. c-MET overexpression is a common event in a wide range of human malignancies, including gastric, lung, breast, ovary, colon, kidney, thyroid, and liver carcinomas. Despite c-MET overexpression being reported by a large majority of studies, no evidence for a c-MET oncogenic addiction exists in hepatocellular carcinoma (HCC). In particular, c-MET amplification is a rare event, accounting for 4%–5% of cases while no mutation has been identified in c-MET oncogene in HCC. Thus, the selection of patient subgroups more likely to benefit from c-MET inhibition is challenging. Notwithstanding, c-MET overexpression was reported to be associated with increased metastatic potential and poor prognosis in patients with HCC, providing a rationale for its therapeutic inhibition. Here we summarize the role of activated HGF/MET signaling in HCC, its prognostic relevance, and the implications for therapeutic approaches in HCC.

The clinical and functional significance of c-Met in breast cancer: a review

c-Met is a receptor tyrosine kinase that upon binding of its ligand, hepatocyte growth factor (HGF), activates downstream pathways with diverse cellular functions that are important in organ development and cancer progression. Anomalous c-Met signalling has been described in a variety of cancer types, and the receptor is regarded as a novel therapeutic target. In breast cancer there is a need to develop new treatments, particularly for the aggressive subtypes such as triple-negative and basal-like cancer, which currently lack targeted therapy. Over the last two decades, much has been learnt about the functional role of c-Met signalling in different models of breast development and cancer. This work has been complemented by clinical studies, establishing the prognostic significance of c-Met in tissue samples of breast cancer. While the clinical trials of anti-c-Met therapy in advanced breast cancer progress, there is a need to review the existing evidence so that the potential of these treatments can be better appreciated. The aim of this article is to examine the role of HGF/c-Met signalling in in vitro and in vivo models of breast cancer, to describe the mechanisms of aberrant c-Met signalling in human tissues, and to give a brief overview of the anti-c-Met therapies currently being evaluated in breast cancer patients. We will show that the HGF/c-Met pathway is associated with breast cancer progression and suggest that there is a firm basis for continued development of anti-c-Met treatment, particularly for patients with basal-like and triple-negative breast cancer.

Lysophosphatidic acid alters the expression profiles of angiogenic factors, cytokines, and chemokines in mouse liver sinusoidal endothelial cells

BACKGROUND AND AIMS

Lysophosphatidic acid (LPA) is a multi-function glycerophospholipid. LPA affects the proliferation of hepatocytes and stellate cells in vitro, and in a partial hepatectomy induced liver regeneration model, the circulating LPA levels and LPA receptor (LPAR) expression levels in liver tissue are significantly changed. Liver sinusoidal endothelial cells (Lsecs) play an important role during liver regeneration. However, the effects of LPA on Lsecs are not well known. Thus, we investigated the effects of LPA on the expression profiles of angiogenic factors, cytokines, and chemokines in Lsecs.

METHODS

Mouse Lsecs were isolated using CD31-coated magnetic beads. The mRNA expression levels of LPAR's and other target genes were determined by quantitative RT-PCR. The protein levels of angiogenesis factors, cytokines, and chemokines were determined using protein arrays and enzyme immunoassay (EIA). Critical LPAR related signal transduction was verified by using an appropriate chemical inhibitor.

RESULTS

LPAR1 and LPAR3 mRNA's were expressed in mouse LPA-treated Lsecs. Treating Lsecs with a physiological level of LPA significantly enhanced the protein levels of angiogenesis related proteins (cyr61 and TIMP-1), cytokines (C5/C5a, M-CSF, and SDF-1), and chemokines (MCP-5, gp130, CCL28, and CXCL16). The LPAR1 and LPAR3 antagonist ki16425 significantly inhibited the LPA-enhanced expression of cyr61, TIMP-1, SDF-1, MCP-5, gp130, CCL28, and CXCL16, but not that of C5/C5a or M-CSF. LPA-induced C5/C5a and M-CSF expression may have been through an indirect regulation mechanism.

CONCLUSION

LPA regulated the expression profiles of angiogenic factors, cytokines, and chemokines in Lsecs that was mediated via LPAR1 and LPAR3 signaling. Most of the factors that were enhanced by LPA have been found to play critical roles during liver regeneration. Thus, these results may prove useful for manipulating LPA effects on liver regeneration.

New therapies for chronic obstructive pulmonary disease, lung regeneration

Chronic obstructive pulmonary disease (COPD) is characterized by the presence of airflow limitations that are not fully reversible and is a major cause of chronic morbidity and mortality worldwide. Although there has been extensive research examining the molecular mechanisms underlying the development of COPD, there is no proven clinically effective treatment for promoting recovery from established COPD. At present, regeneration is the only hope for a cure in patients with COPD. In this article, we review current treatments for COPD, focusing particularly on recent advances in lung regeneration based on two major approaches: regeneration-promoting agents and cell therapy. Retinoic acids are the major focus among regeneration-promoting agents, while mesenchymal stem cells are the main topic in the field of cell-based therapy. This article aims to provide valuable information for developing new therapies for COPD.

Semi-synthesis of a HGF/SF kringle one (K1) domain scaffold generates a potent in vivo MET receptor agonist

The development of MET receptor agonists is an important goal in regenerative medicine, but is limited by the complexity and incomplete understanding of its interaction with HGF/SF (Hepatocyte Growth Factor/Scatter Factor). NK1 is a natural occurring agonist comprising the N-terminal (N) and the first kringle (K1) domains of HGF/SF. In the presence of heparin, NK1 can self-associate into a "head to tail" dimer which is considered as the minimal structural module able to trigger MET dimerization and activation whereas isolated K1 and N domains showed a weak or a complete lack of agonistic activity respectively. Starting from these structural and biological observations, we investigated whether it was possible to recapitulate the biological properties of NK1 using a new molecular architecture of isolated N or K1 domains. Therefore, we engineered multivalent N or K1 scaffolds by combining synthetic and homogeneous site-specifically biotinylated N and K1 domains (NB and K1B) and streptavidin (S). NB alone or in complex failed to activate MET signaling and to trigger cellular phenotypes. Importantly and to the contrary of K1B alone, the semi-synthetic K1B/S complex mimicked NK1 MET agonist activity in cell scattering, morphogenesis and survival phenotypic assays. Impressively, K1B/S complex stimulated in vivo angiogenesis and, when injected in mice, protected the liver against fulminant hepatitis in a MET dependent manner whereas NK1 and HGF were substantially less potent. These data reveal that without N domain, proper multimerization of K1 domain is a promising strategy for the rational design of powerful MET agonists.

Enhanced antioxidant capacity of dental pulp-derived iPSC-differentiated hepatocytes and liver regeneration by injectable HGF-releasing hydrogel in fulminant hepatic failure

Acute hepatic failure (AHF) is a severe liver injury leading to sustained damage and complications. Induced pluripotent stem cells (iPSCs) may be an alternative option for the treatment of AHF. In this study, we reprogrammed human dental pulp-derived fibroblasts into iPSCs, which exhibited pluripotency and the capacity to differentiate into tridermal lineages, including hepatocyte-like cells (iPSC-Heps). These iPSC-Heps resembled human embryonic stem cell-derived hepatocyte-like cells in gene signature and hepatic markers/functions. To improve iPSC-Heps engraftment, we next developed an injectable carboxymethyl-hexanoyl chitosan hydrogel (CHC) with sustained hepatocyte growth factor (HGF) release (HGF-CHC) and investigated the hepatoprotective activity of HGF-CHC-delivered iPSC-Heps in vitro and in an immunocompromised AHF mouse model induced by thioacetamide (TAA). Intrahepatic delivery of HGF-CHC-iPSC-Heps reduced the TAA-induced hepatic necrotic area and rescued liver function and recipient viability. Compared with PBS-delivered iPSC-Heps, the HGF-CHC-delivered iPSC-Heps exhibited higher antioxidant and antiapoptotic activities that reduced hepatic necrotic area. Importantly, these HGF-CHC-mediated responses could be abolished by administering anti-HGF neutralizing antibodies. In conclusion, our findings demonstrated that HGF mediated the enhancement of iPSC-Hep antioxidant/antiapoptotic capacities and hepatoprotection and that HGF-CHC is as an excellent vehicle for iPSC-Hep engraftment in iPSC-based therapy against AHF.

HGF Modulates Actin Cytoskeleton Remodeling and Contraction in Testicular Myoid Cells

The presence of the HGF/Met system in the testicular myoid cells was first discovered by our group. However, the physiological role of this pathway remains poorly understood. We previously reported that HGF increases uPA secretion and TGF-β activation in cultured tubular fragments and that HGF is maximally expressed at Stages VII–VIII of the seminiferous epithelium cycle, when myoid cell contraction occurs. It is well known that the HGF/Met pathway is involved in cytoskeletal remodeling; moreover, the interaction of uPA with its receptor, uPAR, as well as the activation of TGF-β have been reported to be related to the actin cytoskeleton contractility of smooth muscle cells. Herein, we report that HGF induces actin cytoskeleton remodeling in vitro in isolated myoid cells and myoid cell contraction in cultured seminiferous tubules. To better understand these phenomena, we evaluated: (1) the regulation of the uPA machinery in isolated myoid cells after HGF administration; and (2) the effect of uPA or Met inhibition on HGF-treated tubular fragments. Because uPA activates latent TGF-β, the secretion of this factor was also evaluated. We found that both uPA and TGF-β activation increase after HGF administration. In testicular tubular fragments, HGF-induced TGF-β activation and myoid cell contraction are abrogated by uPA or Met inhibitor administration.

Clinical significance of hepatocyte growth factor/c-Met expression in the assessment of gastric cancer progression

Among the mechanisms that control cancer progression, cell mobility is a significant factor required for cellular liberation from the primary focus and infiltration. Hepatocyte growth factor (HGF) has been shown to facilitate cell mobility. In the present study, the clinical significance of the HGF/c-Met pathway in the assessment of gastric cancer progression was evaluated. From a cohort of patients with gastric cancer who underwent surgical resection between April 1999 and March 2003, 110 subjects were randomly selected. Preoperative serum HGF levels were measured and various pathological factors were analyzed. Furthermore, 50 subjects were randomly selected from within this group and immunohistochemical staining of tissue preparations for HGF and its receptor c-Met were performed. In the infiltrative growth pattern [(INF)α,β vs. INFγ], advanced progression was associated with elevated preoperative serum HGF levels (P<0.001). No correlation was identified between serum HGF levels and immunostaining for HGF or c-Met in the tissue preparations. Immunostaining revealed a significant correlation between c-Met expression and lymphatic vessel invasion (ly0.1 vs. 2.3; P=0.0416), lymph node metastasis (n0.1 vs. 2; P=0.0184) and maximum tumor diameter (≤50 mm vs. >50 mm; P=0.0469). Furthermore, c-Met-positivity was associated with a significant difference in overall survival (P=0.0342), despite stage I and II cases accounting for 82% of the total cohort (41 of 50 cases). These results suggested that the expression of the HGF/c-Met pathway in gastric cancer may be a potential predictive factor for disease progression.

Therapeutic potential of hepatocyte growth factor against cerebral ischemia (Review)

The effective treatment for cerebral ischemia has not yet been established. Hepatocyte growth factor (HGF) is a potent pleiotropic cytokine that is involved in cell and tissue regeneration, including in the central nervous system. Studies have demonstrated that an exogenous administration of HGF protects brain tissue from ischemic damage. In response to binding to the receptor c-Met, HGF activates the downstream signaling pathways (including the phosphatidylinositol 3-kinase/Akt, Ras/MAPK and signal transducer and activator of transcription pathways) which leads to various cellular responses involved in angiogenesis, glial scar formation, anti-apoptosis and neurogenesis. The purpose of this review is to summarize the present understanding of the therapeutic potential of HGF in cerebral ischemia.

Adipose-derived stem cells inhibit epidermal melanocytes through an interleukin-6-mediated mechanism

BACKGROUND

Several investigators have postulated that human adipose-derived stem cells can be used for skin rejuvenation, but there have been few reports about their direct effects on human epidermal melanocytes. The authors studied the effects on melanocytes, and the causative agent of those effects was further investigated in this study.

METHODS

Human epidermal melanocytes were divided into three groups and cultured in adipose-derived stem cell-conditioned medium, human dermal fibroblast-conditioned medium, or control medium. Concentrations of melanogenic cytokines in these media were measured using enzyme-linked immunosorbent assay kits. After 3 and 7 days of incubation, cell proliferation, melanin content, tyrosinase activity, and melanogenic gene expression were measured. Interleukin-6-neutralizing antibodies were mixed with adipose-derived stem cell-conditioned medium in which human epidermal melanocytes were cultured, and melanocyte growth and melanogenesis were measured again.

RESULTS

Interleukin-6 concentrations in adipose-derived stem cell- and human epidermal melanocyte-conditioned media were 1373 and 495 pg/ml, respectively. Both types of medium suppressed melanocyte proliferation and melanin synthesis (p < 0.05), but adipose-derived stem cell-conditioned medium was more effective than human dermal fibroblast-conditioned medium in inhibition of human epidermal melanocyte proliferation, melanin synthesis, and tyrosinase activity (p < 0.05). Interleukin-6-neutralizing antibody sufficiently reversed the antimelanogenic effects of adipose-derived stem cell-conditioned medium such that human epidermal melanocyte proliferation, melanin content, tyrosinase activity, and tyrosinase mRNA levels were restored (p < 0.05).

CONCLUSIONS

Adipose-derived stem cell-conditioned medium inhibited melanocyte proliferation and melanin synthesis by down-regulating melanogenic enzymes. Interleukin-6 plays a pivotal role in inhibition of melanocytes.

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.

The development of small molecule angiotensin IV analogs to treat Alzheimer's and Parkinson's diseases

Alzheimer's (AD) and Parkinson's (PD) diseases are neurodegenerative diseases presently without effective drug treatments. AD is characterized by general cognitive impairment, difficulties with memory consolidation and retrieval, and with advanced stages episodes of agitation and anger. AD is increasing in frequency as life expectancy increases. Present FDA approved medications do little to slow disease progression and none address the underlying progressive loss of synaptic connections and neurons. New drug design approaches are needed beyond cholinesterase inhibitors and N-methyl-d-aspartate receptor antagonists. Patients with PD experience the symptomatic triad of bradykinesis, tremor-at-rest, and rigidity with the possibility of additional non-motor symptoms including sleep disturbances, depression, dementia, and autonomic nervous system failure. This review summarizes available information regarding the role of the brain renin-angiotensin system (RAS) in learning and memory and motor functions, with particular emphasis on research results suggesting a link between angiotensin IV (AngIV) interacting with the AT4 receptor subtype. Currently there is controversy over the identity of this AT4 receptor protein. Albiston and colleagues have offered convincing evidence that it is the insulin-regulated aminopeptidase (IRAP). Recently members of our laboratory have presented evidence that the brain AngIV/AT4 receptor system coincides with the brain hepatocyte growth factor/c-Met receptor system. In an effort to resolve this issue we have synthesized a number of small molecule AngIV-based compounds that are metabolically stable, penetrate the blood-brain barrier, and facilitate compromised memory and motor systems. These research efforts are described along with details concerning a recently synthesized molecule, Dihexa that shows promise in overcoming memory and motor dysfunctions by augmenting synaptic connectivity via the formation of new functional synapses.

[Thirty years of Met receptor research: from the discovery of an oncogene to the development of targeted therapies]

In 1984, the Met receptor and its ligand, the HGF/SF, were discovered thanks to their ability to induce cell transformation and proliferation. Thirty years of research highlighted their crucial role in the development and homeostasis of various structures, including many epithelial organs. This period also allowed unraveling the structural basis of their interaction and their complex signaling network. In parallel, Met was shown to be deregulated and associated with a poor prognosis in many cancers. Met involvement in resistance to current therapies is also being deciphered. Based on these data, pharmaceutical companies developed a variety of Met inhibitors, some of which are evaluated in phase III clinical trials. In this review, we trace the exemplary track record of research on Met receptor, which allowed moving from bench to bedside through the development of therapies targeting its activity. Many questions still remain unanswered such as the involvement of Met in several processes of development, the mechanisms involving Met in resistance to current therapies or the likely emergence of resistances to Met-targeted therapies.

Association between Hepatocyte Growth Factor (HGF) Gene Polymorphisms and Serum HGF Levels in Patients with Rheumatoid Arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by proliferation and insufficient apoptosis of synovial cell, inflammatory cell infiltration, angiogenesis, and destruction of joints. Hepatocyte growth factor (HGF) has many functions, such as regulation of inflammation, angiogenesis, and inhibition of apoptosis. The purpose of this study was to investigate the association between intron 13 C/A and intron 14 T/C HGF gene polymorphisms and serum HGF levels in patients with RA.

MATERIALS AND METHODS

100 patients with RA and 123 healthy controls were included in this study. Serum HGF concentrations were measured using ELISA kit. Gene polymorphisms were determined by allelic discrimination analysis using the real-time PCR method.

RESULTS

HGF levels, frequency of AA genotype and A allele for intron 13 C/A polymorphism and frequency of CC genotype and C allele for intron 14 T/C polymorphism were increased in patients with RA compared to healthy controls. There was no overall associations between genotypes and serum HGF concentrations in both patient and control groups.

CONCLUSION

Our results indicate that HGF protein and gene may play an important role in the etiopathogenesis of RA. However, further studies are required for a better understanding of mechanisms related to the disease process.

Improvement of peripheral nerve defects using a silicone conduit filled with hepatocyte growth factor

OBJECTIVE

To assess local effects of hepatocyte growth factor (HGF) on peripheral nerve repair in a rat sciatic nerve transection model.

STUDY DESIGN

Sixty male, healthy, white Wistar rats were randomized into 4 experimental groups: In the sham-operated group, sciatic nerve was exposed and manipulated. In the transected control group, the left sciatic nerve was transected. In the silicone graft group (SIL), a 10-mm defect was made and bridged using a silicone tube. The graft was filled with phosphate-buffered saline in the SIL group and with HGF in the SIL/HGF group.

RESULTS

Behavioral testing, sciatic nerve functional study, gastrocnemius muscle mass measurement, and morphometric indices found earlier regeneration of axons in the SIL/HGF than in the SIL group (P < .05). Immunohistochemical study clearly found more positive location of reactions to S-100 in the SIL/HGF group than in the SIL group.

CONCLUSIONS

HGF may have clinical implications for the surgical management of patients after facial nerve transection.

Role of kidney biomarkers of chronic kidney disease: An update

Chronic kidney disease (CKD) is a progressive pathological condition marked by deteriorating renal function over time. Diagnostic of kidney disease depend on serum creatinine level and glomerular filtration rate which is detectable when kidney function become half. The detection of kidney damage in an early stage needs robust biomarkers. Biomarkers allow monitoring the disease progression at initial stages of disease. On the onset of impairment in cellular organization there is perturbation in signaling molecules which are either up-regulated or down-regulated and act as an indicator or biomarker of diseased stage. This review compiled the cell signaling of different kidney biomarkers associated with the onset of chronic kidney diseases. Delay in diagnosis of CKD will cause deterioration of nephron function which leads to End stage renal disease and at that point patients require dialysis or kidney transplant. Detailed information on the complex network in signaling pathway leading to a coordinated pattern of gene expression and regulation in CKD will undoubtedly provide important clues to develop novel prognostic and therapeutic strategies for CKD.

Hepatocyte growth factor promotes long-term survival and axonal regeneration of retinal ganglion cells after optic nerve injury: comparison with CNTF and BDNF

AIMS

Different trophic factors are known to promote retinal ganglion cell survival and regeneration, but each had their own limitations. We report that hepatocyte growth factor (HGF) confers distinct advantages in supporting ganglion cell survival and axonal regeneration, when compared to two well-established trophic factors ciliary neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF).

METHODS

Ganglion cells in adult hamster were injured by cutting the optic nerve. HGF, CNTF, or BDNF was injected at different dosages intravitreally after injury. Ganglion cell survival was quantified at 7, 14, or 28 days postinjury. Peripheral nerve (PN) grafting to the cut optic nerve of the growth factor-injected eye was performed either immediately after injury or delayed until 7 days post-injury. Expression of heat-shock protein 27 and changes in microglia numbers were quantified in different growth factor groups. The cellular distribution of c-Met in the retina was examined by anti-c-Met immunostaining.

RESULTS

Hepatocyte Growth Factor (HGF) was equally potent as BDNF in promoting short-term survival (up to 14 days post-injury) and also supported survival at 28 days post-injury when ganglion cells treated by CNTF or BDNF failed to be sustained. When grafting was performed without delay, HGF stimulated twice the number of axons to regenerate compared with control but was less potent than CNTF. However, in PN grafting delayed for 7 days after optic nerve injury, HGF maintained a better propensity of ganglion cells to regenerate than CNTF. Unlike CNTF, HGF application did not increase HSP27 expression in ganglion cells. Microglia proliferation was prolonged in HGF-treated retinas compared with CNTF or BDNF. C-Met was localized to both ganglion cells and Muller cells, suggesting HGF could be neuroprotective via interacting with both neurons and glia.

CONCLUSION

Compared with CNTF or BDNF, HGF is advantageous in sustaining long-term ganglion cell survival and their propensity to respond to favorable stimuli.

The potential roles of hepatocyte growth factor (HGF)-MET pathway inhibitors in cancer treatment

MET is located on chromosome 7q31 and is a proto-oncogene that encodes for hepatocyte growth factor (HGF) receptor, a member of the receptor tyrosine kinase (RTK) family. HGF, also known as scatter factor (SF), is the only known ligand for MET. MET is a master regulator of cell growth and division (mitogenesis), mobility (motogenesis), and differentiation (morphogenesis); it plays an important role in normal development and tissue regeneration. The HGF-MET axis is frequently dysregulated in cancer by MET gene amplification, translocation, and mutation, or by MET or HGF protein overexpression. MET dysregulation is associated with an increased propensity for metastatic disease and poor overall prognosis across multiple tumor types. Targeting the dysregulated HGF-MET pathway is an area of active research; a number of monoclonal antibodies to HGF and MET, as well as small molecule inhibitors of MET, are under development. This review summarizes the key biological features of the HGF-MET axis, its dysregulation in cancer, and the therapeutic agents targeting the HGF-MET axis, which are in development.

Expression of growth‑regulated oncogene‑1, hepatocyte growth factor, platelet‑derived growth factor‑AA and soluble E‑selectin and their association with high‑risk human papillomavirus infection in squamous cell carcinoma of the uterine cervix

The aim of the present study was to evaluate the clinical significance and prognostic value of growth‑regulated oncogene‑1 (GRO‑1), hepatocyte growth factor (HGF), platelet‑derived growth factor‑AA (PDGF‑AA), soluble E‑selectin (sE‑selectin) and high‑risk human papillomavirus (HPV; types 16, 18/45, 31 and 33/52/58/67) infection in cervical squamous cell carcinoma (CSCC). A total of 426 cases were enrolled in the present study, of which 292 cases were patients with CSCC, 43 were patients with cervical intraepithelial neoplasia (CIN) and 91 were healthy controls. Luminex xMAP technology was used to detect the serum levels of GRO‑1, HGF, PDGF‑AA and sE‑selectin in all cases and two‑channel fluorescence quantitative polymerase chain reaction was used to determine HPV DNA in cervical scrapings from CSCC and CIN patients. The results demonstrated that the serum levels of GRO‑1, HGF and sE‑selectin were significantly higher in patients with CSCC compared with patients with CIN and the healthy controls (P<0.0001). Compared with the CIN patients, the HPV positive rate in the CSCC patients significantly increased (P=0.013). The four factors were correlated with certain clinicopathological variables of CSCC patients to a certain degree (P<0.05) and the levels of HGF were closely associated with HPV infection (P=0.039). The receiver operating characteristic curves demonstrated that HGF obtained the highest diagnostic value compared with the other three factors. Multivariate Cox regression analysis demonstrated that the serum levels of HGF (P<0.0001), FIGO stage (P<0.0001) and pelvic lymph node metastasis (P=0.001) were independent prognostic factors in patients with CSCC, while high‑risk HPV infection did not show any significance in this analysis. These results demonstrated that HGF may be a useful prognostic biomarker rather than high‑risk HPV types in patients with CSCC.

Synthesis of IL-6 by hepatocytes is a normal response to common hepatic stimuli

Exogenous interleukin 6 (IL-6), synthesized at the initiation of the acute phase response, is considered responsible for signaling hepatocytes to produce acute phase proteins. It is widely posited that IL-6 is either delivered to the liver in an endocrine fashion from immune cells at the site of injury, or alternatively, in a paracrine manner by hepatic immune cells within the liver. A recent publication showed there was a muted IL-6 response in lipopolysaccharide (LPS)-injured mice when nuclear NFκB was specifically inactivated in the hepatocytes. This indicates hepatocellular signaling is also involved in regulating the acute phase production of IL-6. Herein, we present extensive in vitro and in vivo evidence that normal hepatocytes are directly induced to synthesize IL-6 mRNAs and protein by challenge with LPS, a bacterial hepatotoxin, and by HGF, an important regulator of hepatic homeostasis. As the IL-6 receptor is found on the hepatocyte, these results reveal that induction of the acute phase response can be regulated in an autocrine as well as endocrine/paracrine fashion. Further, herein we provide data indicating that following partial hepatectomy (PHx), HGF differentially regulates IL-6 production in hepatocytes (induces) versus immune cells (suppresses), signifying disparate regulation of the cell sources involved in IL-6 production is a biologically relevant mechanism that has previously been overlooked. These findings have wide ranging ramifications regarding how we currently interpret a variety of in vivo and in vitro biological models involving elements of IL-6 signaling and the hepatic acute phase response.

Pleiotropic Activities of HGF/c-Met System in Testicular Physiology: Paracrine and Endocrine Implications

In the last decades, a growing body of evidence has been reported concerning the expression and functional role of hepatocyte growth factor (HGF) on different aspects of testicular physiology. This review has the aim to summarize what is currently known regarding this topic. From early embryonic development to adult age, HGF and its receptor c-Met appeared to be clearly detectable in the testis. These molecules acquire different distribution patterns and roles depending on the developmental stage or the post-natal age considered. HGF acts as a paracrine modulator of testicular functions promoting the epithelium-mesenchyme cross-talk as described even in other organs. Interestingly, it has been reported that testicular HGF acts even as an autocrine factor and that its receptor might be modulated by endocrine signals that change at puberty: HGF receptor expressed by Sertoli cells, in fact, is up-regulated by FSH administration. HGF is in turn able to modify endocrine state of the organism being able to increase testosterone secretion of both fetal and adult Leydig cells. Moreover, c-Met is expressed in mitotic and meiotic male germ cells as well as in spermatozoa. The distribution pattern of c-Met on sperm cell membrane changes in the caput and cauda epididymal sperms and HGF is able to maintain epididymal sperm motility in vitro suggesting a physiological role of this growth factor in the acquisition of sperm motility. Noteworthy changes in HGF concentration in seminal plasma have been reported in different andrological diseases. All together these data indicate that HGF has a role in the control of spermatogenesis and sperm quality either directly, acting on male germ cells, or indirectly acting on tubular and interstitial somatic cells of the testis.

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.

Targeting the hepatocyte growth factor/c-Met signaling pathway in renal cell carcinoma

The product of a proto-oncogene, the c-Met protein is a transmembrane receptor tyrosine kinase. Its only known ligand, hepatocyte growth factor/scatter factor, regulates cell growth, motility, migration, invasion, proliferation, and angiogenesis. Dysregulation of c-Met and hepatocyte growth factor have been observed in both clear cell and non-clear cell renal cell carcinomas (RCCs), although only papillary RCCs harbor activating mutations in the MET gene. In clear cell RCC, there is evidence of a direct link between loss of von Hippel-Lindau and up-regulation of c-Met. As in other cancers, high expression of c-Met correlates with worse outcomes in RCC. In vitro and in vivo preclinical RCC models demonstrate cancer control with small molecule and antibodies against c-Met. Given these findings, the c-Met pathway is a logical therapeutic target in RCC, and several agents are in clinical testing with early signs of efficacy.

Signal transduction in podocytes--spotlight on receptor tyrosine kinases

The mammalian kidney filtration barrier is a complex multicellular, multicomponent structure that maintains homeostasis by regulating electrolytes, acid-base balance, and blood pressure (via maintenance of salt and water balance). To perform these multiple functions, podocytes--an important component of the filtration apparatus--must process a series of intercellular signals. Integrating these signals with diverse cellular responses enables a coordinated response to various conditions. Although mature podocytes are terminally differentiated and cannot proliferate, they are able to respond to growth factors. It is possible that the initial response of podocytes to growth factors is beneficial and protective, and might include the induction of hypertrophic cell growth. However, extended and/or uncontrolled growth factor signalling might be maladaptive and could result in the induction of apoptosis and podocyte loss. Growth factors signal via the activation of receptor tyrosine kinases (RTKs) on their target cells and around a quarter of the 58 RTK family members that are encoded in the human genome have been identified in podocytes. Pharmacological inhibitors of many RTKs exist and are currently used in experimental and clinical cancer therapy. The identification of pathological RTK-mediated signal transduction pathways in podocytes could provide a starting point for the development of novel therapies for glomerular disorders.

Met as a therapeutic target in HCC: facts and hopes

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide, and its burden is expected to increase further in the next years. In spite of the advances of classical therapies, such as surgery, transplantation, use of radiofrequency and transarterial embolization, the prognosis of this neoplasm has not considerably improved over the past few years. The advent of targeted therapies and the approval of the systemic treatment of advanced HCC with the kinase inhibitor sorafenib have provided some hope for the future. Even if the molecular mechanisms responsible for the onset and progression of HCC are still largely unknown, new therapeutic targets have recently come to the spotlight. One of these targets is the tyrosine kinase receptor for the Hepatocyte Growth Factor, encoded by the MET gene, known to promote tumor growth and metastasis in many human organs. In this review we will summarize the contrasting results obtained in vitro (in HCC cell lines) and in animal experimental models and we will also try to analyze the reasons for the opposite findings, suggesting that the HGF/MET axis can have either a promoting or a suppressive role in the development of HCC. We will also reconsider the evidence of activation of this pathway in human HCCs and discuss the results of the clinical trials performed with MET inhibitors. The final purpose is to better clarify which can be the role of MET as a therapeutic target in HCC.

Analysis of HGF, MACC1, C-met and apoptosis-related genes in cervical carcinoma mice

To understand the underlying pharmacological basis and the molecular mechanism of Taxol in therapy of cervical carcinoma (CC) disease, we need to explore the effect of Taxol on CC-related genes and pro-apoptosis and anti-apoptosis genes expression. Immunohistochemistry, western blot and reverse transcription-polymerase chain reaction were applied to examine postive expression levels of Bcl-2, Bax and Caspase-3, HGF, MACC1, Caspase-3 and C-met proteins and MACC1 mRNA expression in tumour of CC mice. Results showed that treatment of Taxol could increase the inhibition rate of tumour growth, positive expression levels of Caspase-3, Bax and decrease positive expression levels of Bcl-2 and Bcl-2/Bax, expression levels of HGF, MACC1 and C-met proteins and MACC1 mRNA in tumour tissue of CC mice. It can be concluded that inhibitory activity of Taxol against tumour growth in CC mice is closely associated with its modulating positive expression of Bcl-2, Bax, Caspase-3, expression of HGF, MACC1, Caspase-3 and C-met proteins and MACC1 mRNA in tumour of CC mice. In conclusion, HGF, MACC1 and C-met genes involve into malignant cervical tumors occurrence, development and prognosis, and might become potential molecular target therapy site of cervical cancer. Taxol intervention may serve as a multi-targeted CC therapeutic capable of inducing selective cancer cell death.

Yhhu3813 is a novel selective inhibitor of c-Met kinase that inhibits c-Met-dependent neoplastic phenotypes of human cancer cells

AIM

c-Met kinase deregulation is strongly associated with the formation, progression and dissemination of human cancers. In this study we identified Yhhu3813 as a small-molecule inhibitor of c-Met kinase and characterized its antitumor properties both in vitro and in vivo.

METHODS

The activities of different kinases were measured using ELISA assays and signaling proteins in the cells were detected with Western blotting. Cell proliferation was assessed using SRB or MTT assay in twenty human cell lines and cell cycle distribution was determined with flow cytometry. Transwell-based assay was used to evaluate cell migration and invasion. Cell invasive growth was detected by a morphogenesis assay. c-Met overactivated human NSCLC cell line EBC-1 xenografts were used to evaluate the in vivo anti-tumor efficacy.

RESULTS

Yhhu3813 potently inhibited c-Met kinase activity in vitro with an IC50 value of 2.4±0.3 nmol/L, >400-fold higher than that for a panel of 15 different tyrosine kinases, suggesting a high selectivity of Yhhu3813. The compound (20, 100 and 500 nmol/L) dose-dependently inhibited the phosphorylation of c-Met and its key downstream Akt and Erk signal cascades in multiple c-Met aberrant human cancer cell lines, regardless of the mechanistic complexity in c-Met activation across different cellular contexts. In 20 human cancer cell lines harboring different backgrounds of c-Met expression/activation, Yhhu3813 potently inhibited c-Met-driven cell proliferation via arresting cells at G1/S phase. Furthermore, Yhhu3813 substantially impaired c-Met-mediated cell migration, invasion, scattering, and invasive growth. Oral administration of EBC-1 xenograft mice with Yhhu3813 (50 or 100 mg·kg(-1)·d(-1), qd, for 2 weeks) dose-dependently suppressed the tumor growth, which was correlated with a reduction in the intratumoral proliferation index and c-Met signaling.

CONCLUSION

Yhhu3813 is a potent selective inhibitor of c-Met that inhibits c-Met-dependent neoplastic phenotypes of human cancer cells in vitro and in vivo.

Peripheral nerve regeneration following transection injury to rat sciatic nerve by local application of adrenocorticotropic hormone

The objective of this study was to assess local effect of adrenocorticotropic hormone (ACTH) on the functional recovery of the sciatic nerve in a transection model. Sixty male healthy white Wistar rats were randomized into four experimental groups of 15 animals each: In the sham-operated group (SHAM), the sciatic nerve was exposed and manipulated. In the transected group (TC), the left sciatic nerve was transected and the cut nerve ends were fixed in the adjacent muscle. In the silicone graft group (SIL) a 10-mm defect was made and bridged using a silicone tube. The graft was filled with phosphated-buffer saline alone. In the treatment group a silicone tube (SIL/ACTH) was filled with 10 μL ACTH (0.1 mg/mL). Each group was subdivided into three subgroups of five animals each and regenerated nerve fibres were studied at 4, 8 and 12 weeks post operation. Behavioral testing, functional, gastrocnemius muscle mass and morphometric indices showed earlier regeneration of axons in SIL/ACTH than in SIL group (p < 0.05). Immunohistochemistry clearly showed more positive location of reactions to S-100 in SIL/ACTH than in SIL group. ACTH improved functional recovery and morphometric indices of sciatic nerve. This finding supports role of ACTH after peripheral nerve repair and may have clinical implications for the surgical management of patients after nerve transection.

Hepatocyte growth factor is an attractive target for the treatment of pulmonary fibrosis

INTRODUCTION

Pulmonary fibrosis (PF) is a progressive fatal disorder and is characterized by alveolar epithelial injury, myofibroblast proliferation, and extracellular matrix remodeling, resulting in irreversible distortion of lung's architecture. Available therapies are associated with side effects and show restricted efficacy. Therefore, there is an urgent need to find a therapeutic solution to PF. Therapeutic strategies interfering myofibroblast expansion, apoptosis of epithelial and endothelial cells might be beneficial for treatment of PF. Hepatocyte growth factor (HGF), a pleiotropic growth factor, plays an important role in lung development, inflammation, repair, and regeneration. In animal model of PF, administration of recombinant HGF protein or ectopic HGF expression ameliorates fibrosis.

AREAS COVERED

The focus of this review is to highlight HGF as a promising therapeutic approach for the treatment of PF. The review discusses the currently available treatment option for PF as well as highlights the possible beneficial effect of HGF as a drug target.

EXPERT OPINION

HGF with its anti-fibrotic effect provides a promising new therapeutic approach by protecting lung from fibrotic remodeling and also promoting normal regeneration of lung. The development of HGF mimetics may provide a potential attractive therapy for treatment of this devastating and complex disease.

Decreased Hepatocyte Growth Factor (HGF) and Gamma Aminobutyric Acid (GABA) in Individuals with Obsessive-Compulsive Disorder (OCD)

INTRODUCTION

There is support for the role of gamma aminobutyric acid (GABA) in the etiology of mood disorders. Recent research has shown that hepatocyte growth factor (HGF) modulates GABAergic inhibition and seizure susceptibility. This study was designed to determine and correlate plasma levels of HGF and GABA as well as symptom severity in individuals with obsessive-compulsive disorder (OCD).

SUBJECTS AND METHODS

Plasma from 15 individuals with OCD (9 males, 6 females;, mean age 38.7 years) and 17 neurotypical controls (10 males, 7 females; mean age 35.2 years) was assessed for HGF, GABA, urokinase plasminogen activator (uPA), and urokinase plasminogen activator receptor (uPAR) concentration using enzyme-linked immunosorbest assays ELISAs. Symptom severity was assessed in these OCD individuals and compared with HGF and GABA concentrations.

RESULTS

In this preliminary study, individuals with OCD had significantly decreased HGF levels, decreased plasma levels of GABA and decreased uPA. We found that both uPA and uPAR levels correlate with HGF. Both low uPA and low uPAR levels correlate with high symptom severity in individuals with OCD. Low GABA levels in OCD individuals also correlate with high symptom severity.

DISCUSSION

These results demonstrate a preliminary association between HGF, GABA, uPA levels, and OCD and suggest that plasma GABA and uPA levels are related to symptom severity in individuals with OCD.

Independent association of elevated serum hepatocyte growth factor levels with development of insulin resistance in a 10-year prospective study

OBJECTIVE

Hepatocyte growth factor (HGF) receptors form a hybrid complex with insulin receptors in the liver of mice, which lead to robust signalling to regulate glucose metabolism. Serum HGF levels are high in subjects with metabolic syndrome and/or obesity. Accordingly, we prospectively investigated the relationship between HGF and the development of insulin resistance (IR) in a general population without IR at baseline.

METHODS

A total of 1492 subjects received health examinations. After excluding subjects with diabetes and/or IR (n = 402) at baseline, the remaining subjects (n = 1090) were followed-up 10 years later. Complete data sets were available from 716 subjects for prospective analysis. Logistic regression was performed to determine factors associated with the development of IR after 10 years.

RESULTS

In subjects without diabetes at baseline, serum HGF levels were higher (0·26 ± 0·10 ng/ml, n = 259) in subjects with IR than without it (0·22 ± 0·09 ng/ml, n = 1090). After deleting subjects who developed liver disease during follow-up, 188 were found to have developed IR at 10 years after the original screening. HGF (P < 0·05), age (P < 0·001), homoeostasis model assessment index (P < 0·001), HDL-c (P < 0·05; inversely) and hypertensive medication (P < 0·05) were significantly associated with the development of IR by multivariate stepwise logistic regression analysis. A significant (P < 0·05) relative risk [1·75 (95%CI: 1·01-3·12)] for the development of IR was observed in the highest (≥0·30 ng/ml) vs the lowest categories (<0·15 ng/ml) of HGF after adjustments for confounders.

CONCLUSIONS

Our 10-year prospective study suggests that elevated serum HGF levels were significantly associated with the development of IR.

Correlation Between Hepatocyte Growth Factor (HGF) and Gamma-Aminobutyric Acid (GABA) Plasma Levels in Autistic Children

There is much support for the role of Gamma-Aminobutyric acid (GABA) in the etiology of autism. Recent research has shown that hepatocyte growth factor (HGF) modulates GABAergic inhibition and seizure susceptibility. This study was designed to determine and correlate plasma levels of HGF, GABA, as well as symptom severity, in autistic children and neurotypical controls. Plasma from 48 autistic children and 29 neurotypical controls was assessed for HGF and GABA concentration using ELISAs. Symptom severity was assessed in these autistic individuals and compared to HGF and GABA concentrations. We previously reported that autistic children had significantly decreased levels of HGF. In this study, the same autistic children had significantly increased plasma levels of GABA (P = 0.002) and decreased HGF levels correlated with these increased GABA levels (r = 0.3; P = 0.05). High GABA levels correlated with increasing hyperactivity (r = 0.6; P = 0.0007) and impulsivity severity (r = 0.5; P = 0.007), tip toeing severity (r = 0.35; P = 0.03), light sensitivity (r = 0.4; P = 0.02), and tactile sensitivity (r = 0.4; P = 0.01). HGF levels did not correlate significantly with any symptom severity. These results suggest an association between HGF and GABA levels and suggest that plasma GABA levels are related to symptom severity in autistic children.