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

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

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

SIGNIFICANCE STATEMENT

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

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.

Short-fiber protein of ad40 confers enteric tropism and protection against acidic gastrointestinal conditions

The lack of vectors for selective gene delivery to the intestine has hampered the development of gene therapy strategies for intestinal diseases. We hypothesized that chimeric adenoviruses of Ad5 (species C) displaying proteins of the naturally enteric Ad40 (species F) might hold the intestinal tropism of the species F and thus be useful for gene delivery to the intestine. As oral-fecal dissemination of enteric adenovirus must withstand the conditions encountered in the gastrointestinal tract, we studied the resistance of chimeric Ad5 carrying the short-fiber protein of Ad40 to acid milieu and proteases and found that the Ad40 short fiber confers resistance to inactivation in acidic conditions and that AdF/40S was further activated upon exposure to low pH. In contrast, the chimeric AdF/40S exhibited only a slightly higher protease resistance compared with Ad5 to proteases present in simulated gastric juice. Then, the biodistribution of different chimeric adenoviruses by oral, rectal, and intravenous routes was tested. Expression of reporter β-galactosidase was measured in extracts of 15 different organs 3 days after administration. Our results indicate that among the chimeric viruses, only intrarectally given AdF/40S infected the colon (preferentially enteroendocrine cells and macrophages) and to a lesser extent, the small intestine, whereas Ad5 infectivity was very poor in all tissues. Additional in vitro experiments showed improved infectivity of AdF/40S also in different human epithelial cell lines. Therefore, our results point at the chimeric adenovirus AdF/40S as an interesting vector for selective gene delivery to treat intestinal diseases.

Intrarectal administration of mCRAMP-encoding plasmid reverses exacerbated colitis in Cnlp(-/-) mice

Cathelicidin is a pleiotropic host defense peptide secreted by epithelial and immune cells. Whether endogenous cathelicidin is protective against ulcerative colitis, however, is unclear. Here we sought to delineate the role of endogenous murine cathelicidin (mCRAMP) and the therapeutic efficacy of intrarectal administration of mCRAMP-encoding plasmid in ulcerative colitis using dextran sulfate sodium (DSS)-challenged cathelicidin-knockout (Cnlp(-/-)) mice as a model. Cnlp(-/-) mice had more severe symptoms and mucosal disruption than the wild-type mice in response to DSS challenge. The tissue levels of interleukin-1β and tumor necrosis factor-α, myeloperoxidase activity and the number of apoptotic cells were increased in the colon of DSS-challenged Cnlp(-/-) mice. Moreover, mucus secretion and mucin gene expression were impaired in Cnlp(-/-) mice. All these abnormalities were reversed by the intrarectal administration of mCRAMP or mCRAMP-encoding plasmid. Taken together, endogenous cathelicidin may protect against ulcerative colitis through modulation of inflammation and mucus secretion.

Effect of oral hepatocyte growth factor gene mediated by attenuated salmonella on 2-, 4-, 6-trinitro-benzene-sulfonic-acid-induced ulcerative colitis in rat

BACKGROUND AND AIM

In order to explore a new therapeutic method, we investigated the effects of exogenously expressed hepatocyte growth factor mediated by attenuated salmonella (TPH) on rats with ulcerative colitis (UC) induced by 2-, 4-, 6-trinitro-benzene-sulfonic acid.

METHODS

The UC rats were treated with TPH, attenuated salmonella with a eukaryotic expression vector (TP) or sodium bicarbonate (model control [MC]) every other day. Cluster of differentiation (CD)4(+) and CD8(+) T cells and immunoglobulins in the blood were analyzed by flow cytometry. The HGF expression was determined by immunohistochemistry. A macroscopic-scale observation of the colon and a histological assessment were also carried out.

RESULTS

The CD4(+) T counts and the CD4(+) /CD8(+) ratio in the TPH group were significantly lower than that in the MC group. The immunoglobulin M and immunoglobulin G(1) levels in the TPH group were significantly lower than that in the MC group and TP group. After treatment with TPH, the symptoms of the ulcerative rats were significantly alleviated. The colonic lesion grades in the TPH group were lower than that in the TP group and MC group. Significant improvement occurred after the TPH treatment, as evidenced by alleviated mucosal inflammation. At 7 days post-treatment, the HGF expression in the colonic tissues that were treated with TPH was stronger than that in the samples treated with TP.

CONCLUSIONS

TPH inhibits the proliferation of T lymphocytes and the antibody production of B lymphocytes. Furthermore, it ameliorates mucosal inflammation and promotes the regeneration of mucosa and the healing of the colonic ulceration.

Prebiotic treatment in experimental colitis reduces the risk of colitic cancer

BACKGROUND AND AIM

  Germinated barley foodstuff (GBF) is a prebiotic product that reduces colonic mucosal inflammation and the clinical symptoms observed in ulcerative colitis (UC). The risk of contracting colorectal cancer is higher in patients with UC than in that of the general population. The aim of this study is to apply this prebiotic approach to control chronic colitis and to reduce the incidence of colitic cancer.

METHODS

  Repeated and intermitted dextran sulfate sodium administration to male Sprague-Dawley rats was used for the chronic and subacute colitis models. GBF was added as the diet (10% w/v). The incidence of adenomatous high-grade dysplasia, and pathophysiological observations, including the proliferative cell nuclear antigen (PCNA) labeling index, and clinical score, cecal organic acid profile, and the accompanying β-glucosidase activity were determined.

RESULTS

  In the chronic phase, the incidence of adenomatous dysplasia was only confirmed in the control group, and the GBF group had no dysplasia in the entire colon; the stratified squamous epithelium area of GBF was significantly lower than that of the controls. GBF treatment significantly lowered the cecal succinate content and significantly increased β-glucosidase activity compared to the controls. In addition, colonic mucosal inflammatory damage was comparable between the two groups, while the PCNA labeling index of the colonic mucosa in the GBF group was significantly lower than that of the control group. However, in the subacute phase, the mucosal damage score of GBF was significantly attenuated, and the PCNA labeling index of the colonic mucosa in the GBF group was significantly higher than that of the control group.

CONCLUSION

  This preliminary study demonstrated that GBF effectively prevents colitis-related dysplasia and inflammatory change in chronic and subacute colitis models by modulating the intestinal environment as a prebiotic. This prebiotic might contribute to the prevention of mucosal damage, to show different proliferative effects on the epithelium in the regeneration and steady states.

Interleukin-10 and inflammatory bowel disease

The etiology of inflammatory bowel disease (IBD) has not been fully elucidated. Evidence indicates that dysregulation of intestinal mucosal immunity plays a critical role in the pathogenesis of IBD since it can cause overproduction of inflammatory cytokines and lead to uncontrolled intestinal inflammation. Cytokines play a pivotal role in modulating inflammation and may therefore be a good target for IBD therapy. Interleukin-10 (IL-10) is a regulatory cytokine which inhibits both antigen presentation and subsequent pro-inflammatory cytokine release and has been proposed as a potent anti-inflammatory biological therapy for chronic IBD. Many IL-10-based strategies have been developed for treatment of IBD, including recombinant IL-10, genetically modified bacteria expressing IL-10, adenoviral vectors encoding IL-10, and combination therapy with IL-10 and Treg cells. The use of IL-10-based strategies will provide new insights into cell- and gene-based treatment for IBD.

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

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

Distribution of attenuated salmonellae carrying hepatocyte growth factor genes in murine gastric ulcers

AIM: To highlight tissue distribution of attenuated salmonellae carrying hepatocyte growth factor (HGF) genes in murine gastric ulcers and thereby to provide a basis for HGF application in gene therapy for gastric ulcers.

METHODS: Eighty acetic acid-induced gastric ulcer rats were randomly divided into two groups: HGF treatment group (n = 40 rats) and green fluorescent protein (GFP) treatment group (n = 40 rats). Intragastric administration of attenuated salmonellae carrying HGF and GFP was performed on rats, each one with 0.2 mL, and once every two days for totally 3 times. Three rats in GFP group were killed each time on day 1, 3, 5, 7, 9 and frozen sections were made from stomach, liver, intestines, spleen and kidney to observe tissue distribution of target genes under fluorescence microscopy; 3 rats in HCF group were killed each time on day 1, 3, 5, 7, 9, 11, 13, 15, 17, 19 and 21 to obverse tissue expression using ELISA and to detect tissue distribution of eukaryotic expression vector using PCR.

RESULTS: In GFP group, some strong fluorescence was observed in the stomach and intestines under fluorescence microscopy, and weak fluorescence in liver, spleen and kidneys. The intensity of fluorescence reached its peak on day 5 and day 7. In HGF group, high-level HGF gene expression by ELISA was detected in stomach, liver, spleen, kidney and intestines with higher expression in the intestines and stomach. CMV promoter fragment of eukaryotic expression vectors was detected in stomach, liver, spleen, kidney, large intestine and small intestine.

CONCLUSION: As a cellular vector, orally-administrated attenuated salmonellae could transfer target genes eukaryotic expression vector into stomach and intestinal tissues for gastric ulcer treatment in rats.

Locally overexpressing hepatocyte growth factor prevents post-ischemic heart failure by inhibition of apoptosis via calcineurin-mediated pathway and angiogenesis

BACKGROUND

Myocardial infarction is a significant cause of heart failure. Currently, therapies are limited and novel revascularization methods may play a role. We investigated the effects of hepatocyte growth factor (HGF) expressed by bone marrow-derived mesenchymal stem cells (MSCs) on post-ischemic heart failure.

METHODS

Four weeks after myocardial infarction (MI), Sprague Dawley rats were randomly divided into saline control group, MSC-GFP group, MSC-HGF group, and MSC-HGF+CsA group. After another 4 weeks, hearts were analyzed for ventricular geometry, myocardial function, angiogenesis and endothelial cell density, apoptosis and the expression of calcineurin, Akt, and Bcl-2 protein.

RESULTS

In MSC-HGF group, rats exhibited better LV systolic and diastolic function compared with other groups after 8 weeks of MI. Angiogenesis was significantly enhanced by HGF through inducing proliferation of endothelial cells. The effects of HGF on apoptosis were associated with the expression level of calcineurin protein.

CONCLUSIONS

Our findings suggest that overexpression of HGF improved ischemic cardiac function through angiogenesis and reduction of apoptosis partly mediated by upregulation of calcineurin.

Insights from advances in research of chemically induced experimental models of human inflammatory bowel disease

Inflammatory bowel disease (IBD), the most important being Crohn's disease and ulcerative colitis, results from chronic dysregulation of the mucosal immune system in the gastrointestinal tract. Although the pathogenesis of IBD remains unclear, it is widely accepted that genetic, environmental, and immunological factors are involved. Recent studies suggest that intestinal epithelial defenses are important to prevent inflammation by protecting against microbial pathogens and oxidative stresses. To investigate the etiology of IBD, animal models of experimental colitis have been developed and are frequently used to evaluate new anti-inflammatory treatments for IBD. Several models of experimental colitis that demonstrate various pathophysiological aspects of the human disease have been described. In this manuscript, we review the characteristic features of IBD through a discussion of the various chemically induced experimental models of colitis (e.g., dextran sodium sulfate-, 2,4,6-trinitrobenzene sulfonic acid-, oxazolone-, acetic acid-, and indomethacin-induced models). We also summarize some regulatory and pathogenic factors demonstrated by these models that can, hopefully, be exploited to develop future therapeutic strategies against IBD.

Hepatocyte growth factor promotes colonic epithelial regeneration via Akt signaling

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