Hepatocyte growth factor gene transfer with naked plasmid DNA ameliorates dimethylnitrosamine-induced liver fibrosis in rats

New Progress of Adipose-derived Stem Cells in the Therapy of Hypertrophic Scars

Burns are a global public health issue of great concern. The formation of scars after burns and physical dysfunction of patients remain major challenges in the treatment of scars. Regenerative medicine based on cell therapy has become a hot topic in this century. Adipose-derived stem cells (ADSCs) play an important role in cellular therapy and have become a promising source of regenerative medicine and wound repair transplantation. However, the anti-scarring mechanism of ADSCs is still unclear yet. With the widespread application of ADSCs in medical, we firmly believe that it will bring great benefits to patients with hypertrophic scars.

CRISPR/Cas9-mediated correction of mutated copper transporter ATP7B

Wilson's disease (WD) is a monogenetic liver disease that is based on a mutation of the ATP7B gene and leads to a functional deterioration in copper (Cu) excretion in the liver. The excess Cu accumulates in various organs such as the liver and brain. WD patients show clinical heterogeneity, which can range from acute or chronic liver failure to neurological symptoms. The course of the disease can be improved by a life-long treatment with zinc or chelators such as D-penicillamine in a majority of patients, but serious side effects have been observed in a significant portion of patients, e.g. neurological deterioration and nephrotoxicity, so that a liver transplant would be inevitable. An alternative therapy option would be the genetic correction of the ATP7B gene. The novel gene therapy method CRISPR/Cas9, which has recently been used in the clinic, may represent a suitable therapeutic opportunity. In this study, we first initiated an artificial ATP7B point mutation in a human cell line using CRISPR/Cas9 gene editing, and corrected this mutation by the additional use of single-stranded oligo DNA nucleotides (ssODNs), simulating a gene correction of a WD point mutation in vitro. By the addition of 0.5 mM of Cu three days after lipofection, a high yield of CRISPR/Cas9-mediated ATP7B repaired cell clones was achieved (60%). Moreover, the repair efficiency was enhanced using ssODNs that incorporated three blocking mutations. The repaired cell clones showed a high resistance to Cu after exposure to increasing Cu concentrations. Our findings indicate that CRISPR/Cas9-mediated correction of ATP7B point mutations is feasible and may have the potential to be transferred to the clinic.

The Efficacy of Topical HGF on Corneal Fibrosis and Epithelial Healing after Scar-Producing PRK Injury in Rabbits

Purpose

To determine the effect of topical hepatocyte growth factor (HGF) on myofibroblast development and corneal opacity after fibrosis-producing photorefractive keratectomy (PRK).

Methods

Twelve New Zealand rabbits had transepithelial PRK. Six rabbits received topical recombinant human HGF (rhHGF) (50 µL of 0.1 mg/mL) 3 times a day for 1 week beginning 6 hours prior surgery and until full closure of the epithelium, and 6 control rabbits received vehicle by the same schedule. Slit lamp photos were taken immediately and at 43 to 45 hours after surgery to determine the rate of epithelial healing. Slit lamp photographs and immunohistochemistry for α-smooth muscle actin were analyzed at 1 month in masked fashion.

Results

The rhHGF group tended to have slower re-epithelization when compared with the controls, but no statistically significant difference was noted (P = 0.62). There was no significant difference in the density of myofibroblasts in the central stroma (P = 0.49) or corneal opacity (P = 0.84) between the HGF and control groups at 1 month after PRK.

Conclusions

Topical rhHGF applied three times a day during the early postoperative period prior to epithelial closure did not significantly change the corneal epithelial healing rate, myofibroblast density, or opacity compared with vehicle after transepithelial -9.0 D PRK injury of the central cornea in rabbits.

Translational Relevance

HGF has been reported to decrease myofibroblast generation and fibrosis in many organs, but topical HGF applied to the cornea until epithelial healing had no effect on scarring fibrosis in rabbit corneas.

The detection of trans gene fragments of hEPO in gene doping model mice by Taqman qPCR assay

Background

With the rapid progress of genetic engineering and gene therapy methods, the World Anti-Doping Agency has raised concerns regarding gene doping, which is prohibited in sports. However, there is no standard method available for detecting transgenes delivered by injection of naked plasmids. Here, we developed a detection method for detecting transgenes delivered by injection of naked plasmids in a mouse model that mimics gene doping.

Methods

Whole blood from the tail tip and one piece of stool were used as pre-samples of injection. Next, a plasmid vector containing the human erythropoietin (hEPO) gene was injected into mice through intravenous (IV), intraperitoneal (IP), or local muscular (IM) injection. At 1, 2, 3, 6, 12, 24, and 48 h after injection, approximately 50 µL whole blood was collected from the tail tip. One piece of stool was collected at 6, 12, 24, and 48 h. From each sample, total DNA was extracted and transgene fragments were analyzed by Taqman quantitative PCR (qPCR) and SYBR green qPCR.

Results

In whole blood DNA samples evaluated by Taqman qPCR, the transgene fragments were detected at all time points in the IP sample and at 1, 2, 3, 6, and 12 h in the IV and IM samples. In the stool-DNA samples, the transgene fragments were detected at 6, 12, 24, and 48 h in the IV and IM samples by Taqman qPCR. In the analysis by SYBR green qPCR, the transgene fragments were detected at some time point in both specimens; however, many non-specific amplicons were detected.

Conclusions

These results indicate that transgene fragments evaluated after each injection method of naked plasmids were detected in whole-blood and stool DNA samples. These findings may facilitate the development of methods for detecting gene doping.

c-Met Signaling Is Essential for Mouse Adult Liver Progenitor Cells Expansion After Transforming Growth Factor-β-Induced Epithelial-Mesenchymal Transition and Regulates Cell Phenotypic Switch

Adult hepatic progenitor cells (HPCs)/oval cells are bipotential progenitors that participate in liver repair responses upon chronic injury. Recent findings highlight HPCs plasticity and importance of the HPCs niche signals to determine their fate during the regenerative process, favoring either fibrogenesis or damage resolution. Transforming growth factor-β (TGF-β) and hepatocyte growth factor (HGF) are among the key signals involved in liver regeneration and as component of HPCs niche regulates HPCs biology. Here, we characterize the TGF-β-triggered epithelial-mesenchymal transition (EMT) response in oval cells, its effects on cell fate in vivo, and the regulatory effect of the HGF/c-Met signaling. Our data show that chronic treatment with TGF-β triggers a partial EMT in oval cells based on coexpression of epithelial and mesenchymal markers. The phenotypic and functional profiling indicates that TGF-β-induced EMT is not associated with stemness but rather represents a step forward along hepatic lineage. This phenotypic transition confers advantageous traits to HPCs including survival, migratory/invasive and metabolic benefit, overall enhancing the regenerative potential of oval cells upon transplantation into a carbon tetrachloride-damaged liver. We further uncover a key contribution of the HGF/c-Met pathway to modulate the TGF-β-mediated EMT response. It allows oval cells expansion after EMT by controlling oxidative stress and apoptosis, likely via Twist regulation, and it counterbalances EMT by maintaining epithelial properties. Our work provides evidence that a coordinated and balanced action of TGF-β and HGF are critical for achievement of the optimal regenerative potential of HPCs, opening new therapeutic perspectives. Stem Cells 2019;37:1108-1118.

Thymosin β4 Prevents Oxidative Stress, Inflammation, and Fibrosis in Ethanol- and LPS-Induced Liver Injury in Mice

Thymosin beta 4 (Tβ4), an actin-sequestering protein, is involved in tissue development and regeneration. It prevents inflammation and fibrosis in several tissues. We investigated the role of Tβ4 in chronic ethanol- and acute lipopolysaccharide- (LPS-) induced mouse liver injury. C57BL/6 mice were fed 5% ethanol in liquid diet for 4 weeks plus binge ethanol (5 g/kg, gavage) with or without LPS (2 mg/kg, intraperitoneal) for 6 hours. Tβ4 (1 mg/kg, intraperitoneal) was administered for 1 week. We demonstrated that Tβ4 prevented ethanol- and LPS-mediated increase in liver injury markers as well as changes in liver pathology. It also prevented ethanol- and LPS-mediated increase in oxidative stress by decreasing ROS and lipid peroxidation and increasing the antioxidants, reduced glutathione and manganese-dependent superoxide dismutase. It also prevented the activation of nuclear factor kappa B by blocking the phosphorylation of the inhibitory protein, IκB, thereby prevented proinflammatory cytokine production. Moreover, Tβ4 prevented fibrogenesis by suppressing the epigenetic repressor, methyl-CpG-binding protein 2, that coordinately reversed the expression of peroxisome proliferator-activated receptor-γ and downregulated fibrogenic genes, platelet-derived growth factor-β receptor, α-smooth muscle actin, collagen 1, and fibronectin, resulting in reduced fibrosis. Our data suggest that Tβ4 has antioxidant, anti-inflammatory, and antifibrotic potential during alcoholic liver injury.

Recent Updates on Treatment of Ocular Microbial Infections by Stem Cell Therapy: A Review

Ocular microbial infection has emerged as a major public health crisis during the past two decades. A variety of causative agents can cause ocular microbial infections; which are characterized by persistent and destructive inflammation of the ocular tissue; progressive visual disturbance; and may result in loss of visual function in patients if early and effective treatments are not received. The conventional therapeutic approaches to treat vision impairment and blindness resulting from microbial infections involve antimicrobial therapy to eliminate the offending pathogens or in severe cases; by surgical methods and retinal prosthesis replacing of the infected area. In cases where there is concurrent inflammation, once infection is controlled, anti-inflammatory agents are indicated to reduce ocular damage from inflammation which ensues. Despite advances in medical research; progress in the control of ocular microbial infections remains slow. The varying level of ocular tissue recovery in individuals and the incomplete visual functional restoration indicate the chief limitations of current strategies. The development of a more extensive therapy is needed to help in healing to regain vision in patients. Stem cells are multipotent stromal cells that can give rise to a vast variety of cell types following proper differentiation protocol. Stem cell therapy shows promise in reducing inflammation and repairing tissue damage on the eye caused by microbial infections by its ability to modulate immune response and promote tissue regeneration. This article reviews a selected list of common infectious agents affecting the eye; which include fungi; viruses; parasites and bacteria with the aim of discussing the current antimicrobial treatments and the associated therapeutic challenges. We also provide recent updates of the advances in stem cells studies on sepsis therapy as a suggestion of optimum treatment regime for ocular microbial infections.

Hepatic Stellate Cells in Liver Fibrosis and siRNA-Based Therapy

Hepatic fibrosis is a reversible wound-healing response to either acute or chronic liver injury caused by hepatitis B or C, alcohol, and toxic agents. Hepatic fibrosis is characterized by excessive accumulation and reduced degradation of extracellular matrix (ECM). Excessive accumulation of ECM alters the hepatic architecture leading to liver fibrosis and cirrhosis. Cirrhosis results in failure of common functions of the liver. Hepatic stellate cells (HSC) play a major role in the development of liver fibrosis as HSC are the main source of the excessive production of ECM in an injured liver. RNA interference (RNAi) is a recently discovered therapeutic tool that may provide a solution to manage multiple diseases including liver fibrosis through silencing of specific gene expression in diseased cells. However, gene silencing using small interfering RNA (siRNA) is encountering many challenges in the body after systemic administration. Efficient and stable siRNA delivery to the target cells is a key issue for the development of siRNA therapeutic. For that reason, various viral and non-viral carriers for liver-targeted siRNA delivery have been developed. This review will cover the current strategies for the treatment of liver fibrosis as well as discussing non-viral approaches such as cationic polymers and lipid-based nanoparticles for targeted delivery of siRNA to the liver.

Pharmacological Intervention in Hepatic Stellate Cell Activation and Hepatic Fibrosis

The activation and transdifferentiation of hepatic stellate cells (HSCs) into contractile, matrix-producing myofibroblasts (MFBs) are central events in hepatic fibrogenesis. These processes are driven by autocrine- and paracrine-acting soluble factors (i.e., cytokines and chemokines). Proof-of-concept studies of the last decades have shown that both the deactivation and removal of hepatic MFBs as well as antagonizing profibrogenic factors are in principle suitable to attenuate ongoing hepatic fibrosis. Although several drugs show potent antifibrotic activities in experimental models of hepatic fibrosis, there is presently no effective pharmaceutical intervention specifically approved for the treatment of liver fibrosis. Pharmaceutical interventions are generally hampered by insufficient supply of drugs to the diseased liver tissue and/or by adverse effects as a result of affecting non-target cells. Therefore, targeted delivery systems that bind specifically to receptors solely expressed on activated HSCs or transdifferentiated MFBs and delivery systems that can improve drug distribution to the liver in general are urgently needed. In this review, we summarize current strategies for targeted delivery of drugs to the liver and in particular to pro-fibrogenic liver cells. The applicability and efficacy of sequestering molecules, selective protein carriers, lipid-based drug vehicles, viral vectors, transcriptional targeting approaches, therapeutic liver- and HSC-specific nanoparticles, and miRNA-based strategies are discussed. Some of these delivery systems that had already been successfully tested in experimental animal models of ongoing hepatic fibrogenesis are expected to translate into clinically useful therapeutics specifically targeting HSCs.

Intralesional injection of adipose-derived stem cells reduces hypertrophic scarring in a rabbit ear model

INTRODUCTION

Redundant collagen deposition at sites of healing dermal wounds results in hypertrophic scars. Adipose-derived stem cells (ADSCs) exhibit promise in a variety of anti-fibrosis applications by attenuating collagen deposition. The objective of this study was to explore the influence of an intralesional injection of ADSCs on hypertrophic scar formation by using an established rabbit ear model.

METHODS

Twelve New Zealand albino rabbits were equally divided into three groups, and six identical punch defects were made on each ear. On postoperative day 14 when all wounds were completely re-epithelialized, the first group received an intralesional injection of ADSCs on their right ears and Dulbecco's modified Eagle's medium (DMEM) on their left ears as an internal control. Rabbits in the second group were injected with conditioned medium of the ADSCs (ADSCs-CM) on their right ears and DMEM on their left ears as an internal control. Right ears of the third group remained untreated, and left ears received DMEM. We quantified scar hypertrophy by measuring the scar elevation index (SEI) on postoperative days 14, 21, 28, and 35 with ultrasonography. Wounds were harvested 35 days later for histomorphometric and gene expression analysis.

RESULTS

Intralesional injections of ADSCs or ADSCs-CM both led to scars with a far more normal appearance and significantly decreased SEI (44.04 % and 32.48 %, respectively, both P <0.01) in the rabbit ears compared with their internal controls. Furthermore, we confirmed that collagen was organized more regularly and that there was a decreased expression of alpha-smooth muscle actin (α-SMA) and collagen type Ι in the ADSC- and ADSCs-CM-injected scars according to histomorphometric and real-time quantitative polymerase chain reaction analysis. There was no difference between DMEM-injected and untreated scars.

CONCLUSIONS

An intralesional injection of ADSCs reduces the formation of rabbit ear hypertrophic scars by decreasing the α-SMA and collagen type Ι gene expression and ameliorating collagen deposition and this may result in an effective and innovative anti-scarring therapy.

Epigenetic modifications by histone deacetylases: Biological implications and therapeutic potential in liver fibrosis

Liver fibrosis is an important pathological repair process in reaction to liver injury characterized by progressive accumulation of extracellular matrix (ECM) components. Mechanism that orchestrates this fibrotic disorder is the activation of hepatic stellate cell (HSC) that requires extensive alterations in gene expression. Reversible deacetylation of histone proteins is one of the most abundant epigenetic modifications and is crucial in modulating gene expression. Recent evidence has highlighted a pathological imbalance between the acetylation and deacetylation of histone proteins regulated by histone deacetylases (HDACs). In the past several years, the role of HDACs in liver fibrosis initiation and progression, as well as the therapeutic effects of HDAC inhibitors, has been well studied. Here, the innovative aspects of histone deacetylation will be presented, with respect to the roles of HDACs in liver fibrosis, the affected genes and signal pathways involved in HSCs activation, as well as significant data emerging from the field in support of HDAC inhibitors as potential therapeutic targets for the treatment of liver fibrosis.

Hepatocyte growth factor regulates the TGF-β1-induced proliferation, differentiation and secretory function of cardiac fibroblasts

Cardiac fibroblast (CF) proliferation and transformation into myofibroblasts play important roles in cardiac fibrosis during pathological myocardial remodeling. In this study, we demonstrate that hepatocyte growth factor (HGF), an antifibrotic factor in the process of pulmonary, renal and liver fibrosis, is a negative regulator of cardiac fibroblast transformation in response to transforming growth factor-β₁ (TGF-β₁). HGF expression levels were significantly reduced in the CFs following treatment with 5 ng/ml TGF-β₁ for 48 h. The overexpression of HGF suppressed the proliferation, transformation and the secretory function of the CFs following treatment with TGF-β₁, as indicated by the attenuated expression levels of α-smooth muscle actin (α-SMA) and collagen I and III, whereas the knockdown of HGF had the opposite effect. Mechanistically, we identified that the phosphorylation of c-Met, Akt and total protein of TGIF was significantly inhibited by the knockdown of HGF, but was significantly enhanced by HGF overexpression. Collectively, these results indicate that HGF activates the c-Met-Akt-TGIF signaling pathway, inhibiting CF proliferation and transformation in response to TGF-β₁ stimulation.

Hepatic stellate cell-targeted delivery of hepatocyte growth factor transgene via bile duct infusion enhances its expression at fibrotic foci to regress dimethylnitrosamine-induced liver fibrosis

Liver fibrosis generates fibrotic foci with abundant activated hepatic stellate cells and excessive collagen deposition juxtaposed with healthy regions. Targeted delivery of antifibrotic therapeutics to hepatic stellate cells (HSCs) might improve treatment outcomes and reduce adverse effects on healthy tissue. We delivered the hepatocyte growth factor (HGF) gene specifically to activated hepatic stellate cells in fibrotic liver using vitamin A-coupled liposomes by retrograde intrabiliary infusion to bypass capillarized hepatic sinusoids. The antifibrotic effects of DsRed2-HGF vector encapsulated within vitamin A-coupled liposomes were validated by decreases in fibrotic markers in vitro. Fibrotic cultures transfected with the targeted transgene showed a significant decrease in fibrotic markers such as transforming growth factor-β1. In rats, dimethylnitrosamine-induced liver fibrosis is manifested by an increase in collagen deposition and severe defenestration of sinusoidal endothelial cells. The HSC-targeted transgene, administered via retrograde intrabiliary infusion in fibrotic rats, successfully reduced liver fibrosis markers alpha-smooth muscle actin and collagen, accompanied by an increase in the expression of DsRed2-HGF near the fibrotic foci. Thus, targeted delivery of HGF gene to hepatic stellate cells increased the transgene expression at the fibrotic foci and strongly enhanced its antifibrotic effects.

Human platelets inhibit liver fibrosis in severe combined immunodeficiency mice

AIM: To investigate the role of human platelets in liver fibrosis.

METHODS: Severe combined immunodeficiency (SCID) mice were administered CCl₄ and either phosphate-buffered saline (PBS group) or human platelet transfusions (hPLT group). Concentrations of hepatocyte growth factor (HGF), matrix metallopeptidases (MMP)-9, and transforming growth factor-β (TGF-β) in the liver tissue were compared between the PBS and the hPLT groups by enzyme-linked immunosorbent assay (ELISA) and Western blotting. The effects of a human platelet transfusion on liver fibrosis included the fibrotic area, hydroxyproline content, and α-smooth muscle actin (α-SMA) expression, which were evaluated by picrosirius red staining, ELISA, and immunohistochemical staining using an anti-mouse α-SMA antibody, respectively. Phosphorylations of mesenchymal-epithelial transition factor (Met) and SMAD3, downstream signals of HGF and TGF-β, were compared between the two groups by Western blotting and were quantified using densitometry. Hepatocyte apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling. Furthermore, the accumulation of human platelets in the liver 2 h after platelet transfusion was compared between normal and fibrotic livers by immunohistochemical staining using an anti-human CD41 antibody.

RESULTS: The fibrotic area and hydroxyproline content in the liver were both significantly lower in the hPLT group when compared to the PBS group (fibrotic area, 1.7% ± 0.6% vs 2.5% ± 0.6%, P = 0.03; hydroxyproline content, 121 ± 26 ng/g liver vs 156 ± 47 ng/g liver, P = 0.04). There was less α-smooth muscle actin staining in the hPLT group than in the PBS group (0.5% ± 0.1% vs 0.8% ± 0.3%, P = 0.02). Hepatic expression levels of mouse HGF and MMP-9 were significantly higher in the hPLT group than in the PBS group (HGF, 109 ± 13 ng/g liver vs 88 ± 22 ng/g liver, P = 0.03; MMP-9, 113% ± 7%/GAPDH vs 92% ± 11%/GAPDH, P = 0.04). In contrast, the concentration of mouse TGF-β in the liver tissue was significantly lower in the hPLT group than in the PBS group (22 ± 5 ng/g liver vs 39 ± 6 ng/g liver, P = 0.02). Phosphorylation of Met was more prevalent in the hPLT group than in the PBS group (37% ± 4%/GAPDH vs 20% ± 8%/GAPDH, P = 0.03). Phosphorylation of SMAD3 was weaker in the hPLT group than in the PBS group (60% ± 12%/GAPDH vs 84% ± 12%/GAPDH, P = 0.1), although this difference was not significant. Furthermore, a lower rate of hepatocyte apoptosis was observed in the hPLT group than in the PBS group (5.9% ± 1.7% vs 2.9% ± 2.1%, P = 0.02). Significant human platelet accumulation was observed in the fibrotic liver tissues, whereas few platelets accumulated in the normal liver.

CONCLUSION: Human platelets inhibit liver fibrosis in SCID mice. Increased concentration of HGF in the liver suppresses hepatic stellate cell activation, induces MMPs, and inhibits hepatocyte apoptosis.

Mesenchymal stem cell therapy for attenuation of scar formation during wound healing

Scars are a consequence of cutaneous wound healing that can be both unsightly and detrimental to the function of the tissue. Scar tissue is generated by excessive deposition of extracellular matrix tissue by wound healing fibroblasts and myofibroblasts, and although it is inferior to the uninjured skin, it is able to restore integrity to the boundary between the body and its environment. Scarring is not a necessary process to repair the dermal tissues. Rather, scar tissue forms due to specific mechanisms that occur during the adult wound healing process and are modulated primarily by the inflammatory response at the site of injury. Adult tissue-derived mesenchymal stem cells, which participate in normal wound healing, are trophic mediators of tissue repair. These cells participate in attenuating inflammation in the wound and reprogramming the resident immune and wound healing cells to favor tissue regeneration and inhibit fibrotic tissue formation. As a result, these cells have been considered and tested as a likely candidate for a cellular therapy to promote scar-less wound healing. This review identifies specific mechanisms by which mesenchymal stem cells can limit tissue fibrosis and summarizes recent in vivo studies where these cells have been used successfully to limit scar formation.

Liver Anti-Fibrosis Therapy with Mesenchymal Stem Cells Secreting Hepatocyte Growth Factor

The objective of this study is to investigate the anti-fibrotic effect of combined mesencymal stem cells (MSCs) and gene therapy on liver fibrosis. When transfected by the complex with a plasmid DNA of hepatocyte growth factor (HGF) and the spermine-introduced pullulan of gene carrier, MSCs secreted HGF protein over 1 week. The HGF secreted from transfected MSC had the biological activity to promote the albumin production of hepatocytes. After intravenous injection, the HGF-secreting MSCs (HGF-MSC) accumulated in the liver. The injection of HGF-MSC decreased the fibrosis area in a rat model of liver fibrosis to a significantly great extent compared with that of original MSC. In the in vitro experiment, the higher number of HGF-transfected MSCs was migrated by stromal cell-derived factor (SDF)-1α more strongly than the original MSC. Considering the promotion of SDF-1α secretion in the liver fibrosis, it is possible that, when transplanted, genetically-engineered MSCs are accumulated in the liver due to their higher response to SDF-1α. It is concluded that the intravenous injection of genetically-engineered MSCs is a promising therapy for liver fibrosis.

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

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

Matrix metalloproteinase-9, -10, and -12, MDM2 and p53 expression in mouse liver during dimethylnitrosamine-induced oxidative stress and genomic injury

Treatment during early tumor development has greater success because tissue growth remains largely confined to its original locus. At later stages, malignant cells migrate from their original location, invade surrounding normal areas, and can disseminate widely throughout the body. Remodeling of the extracellular matrix (ECM) serves as a key facilitator of this dissemination. Proteolytic enzymes including plasmin and matrix metalloproteinases (MMPs) play an integral role in degrading the surrounding ECM proteins and clearing a path for tumor cell migration. Specific MMPs are highly expressed late during malignant tumor invasion. It is not understood whether early changes in MMPs influence apoptotic and necrotic cell death, processes known to govern the early stages of carcinogenesis. Similarly, the interaction between MDM2 and p53 is tightly controlled by a complex array of post-translational modifications, which in turn dictates the stability and activity of both p53 and MDM2. The present studies examine the hypothesis that model hepatotoxin dimethylnitrosamine (DMN), which is also a model carcinogen, will induce the MMP family of proteins after administration in hepatotoxic doses. Doses of 25, 50, and 100 mg/kg DMN were administered i.p. to male C3H mice. Changes in parameters associated with apoptotic and necrotic cell death, DNA damage, cell proliferation, and extracellular proteinases were examined in liver at 24 h. Serum ALT activity, oxidative stress [malondialdehyde], and caspase-activated DNAse mediated DNA laddering increased in a dose-dependent manner, as did the level of MDM2 protein. MMP-9, -10 and -12 (gelatinase-B, stromelysin-2, macrophage elastase), and p53 protein levels increased following 25 mg/kg DMN, but were successively decreased after higher DMN doses. The results of this study demonstrate changes in MDM2 and MMPs during DMN-induced acute liver injury and provide a plausible linkage between DMN-induced oxidative stress-mediated genomic injury and its likely involvement in setting the stage for initiating subsequent metastatic disease at later circumstances.

Concise review: clinical translation of wound healing therapies based on mesenchymal stem cells

There is enormous worldwide demand for therapies to promote the efficient resolution of hard-to-heal wounds with minimal appearance of scarring. Recent in vitro studies with mesenchymal stem cells (MSCs) have identified numerous mechanisms by which these cells can promote the process of wound healing, and there is significant interest in the clinical translation of an MSC-based therapy to promote dermal regeneration. This review provides a systematic analysis of recent preclinical and clinical research to evaluate the use of MSCs in wound healing applications. These in vivo studies provide overwhelming evidence that MSCs can accelerate wound closure by modulating the inflammatory environment, promoting the formation of a well-vascularized granulation matrix, encouraging the migration of keratinocytes, and inhibiting apoptosis of wound healing cells. The trophic effects of MSC therapy also appear to augment wound healing in diabetic tissues, thereby preventing the formation of nonhealing ulcers. Finally, a number of delivery systems have been evaluated and indicate that MSCs could be the basis of a versatile therapy to fulfill the clinical needs for dermal regeneration. However, despite the apparent advantages of MSC-based therapies, there have been only limited clinical investigations of this type of therapy in humans. Thus, our review concludes with a discussion of the translational barriers that are limiting the widespread clinical use of MSCs to enhance wound healing.

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

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

Prolonged amelioration of acute lung allograft rejection by sequential overexpression of human interleukin-10 and hepatocyte growth factor in rats

The effect of prolonged electroporation-mediated human interleukin-10 (hIL-10) overexpression 24 hours before transplantation, combined with sequential human hepatocyte growth factor (HGF) overexpression into skeletal muscle on day 5, on rat lung allograft rejection was evaluated. Left lung allotransplantation was performed from Brown-Norway to Fischer-F344 rats. Gene transfer into skeletal muscle was enhanced by electroporation. Three groups were studied: group I animals (n = 5) received 2.5 μg pCIK-hIL-10 (hIL-10/CMV [cytomegalovirus] early promoter enhancer) on day -1 and 80 μg pCIK-HGF (HGF/CMV early promoter enhancer) on day 5. Group II animals (n = 4) received 2.5 μg pCIK-hIL-10 and pUbC-hIL-10 (hIL-10/pUbC promoter) on day -1. Control group III animals (n = 4) were treated by sham electroporation on days -1 and 5. All animals received daily nontherapeutic intraperitoneal dose of cyclosporin A (2.5 mg/kg) and were sacrificed on day 15. Graft oxygenation and allograft rejection were evaluated. Significant differences were found between study groups in graft oxygenation (Pao(2)) (P = .0028; group I vs. groups II and III, P < .01 each). Pao(2) was low in group II (31 ± 1 mm Hg) and in group III controls (34 ± 10 mm Hg), without statistically significant difference between these 2 groups (P = .54). In contrast, in group I, Pao(2) of recipients sequentially transduced with IL-10 and HGF plasmids was much improved, with 112 ± 39 mm Hg (vs. groups II and III; P < .01 each), paralleled by reduced vascular and bronchial rejection (group I vs. groups II and III, P < .021 each). Sequential overexpression of anti-inflammatory cytokine IL-10, followed by sequential and overlapping HGF overexpression on day 5, preserves lung function and reduces acute lung allograft rejection up to day 15 post transplant as compared to prolonged IL-10 overexpression alone.

Thymosin-β4 (Tβ4) blunts PDGF-dependent phosphorylation and binding of AKT to actin in hepatic stellate cells

Hepatic stellate cell transdifferentiation is a key event in the fibrogenic cascade. Therefore, attempts to prevent and/or revert the myofibroblastic phenotype could result in novel therapeutic approaches to treat liver cirrhosis. The expression of platelet-derived growth factor (PDGF)-β receptor and the proliferative response to platelet-derived growth factor-ββ (PDGF-ββ) are hallmarks of the transdifferentiation of hepatic stellate cells (HSC). In this communication, we investigated whether thymosin-β4 (Tβ4), a chemokine expressed by HSC could prevent PDGF-BB-mediated proliferation and migration of cultured HSC. Using early passages of human HSC, we showed that Tβ4 inhibited cell proliferation and migration and prevented the expression of PDGF-β receptor (PDGF-βr), α-smooth muscle actin and α1(I) collagen mRNAs. Tβ4 also inhibited the reappearance of PDGF-βr after its PDGF-BB-dependent degradation. These PDGF-dependent events were associated with the inhibition of AKT phosphorylation at both T308 and S473 amino acid residues. The lack of AKT phosphorylation was not due to the inhibition of PDGF-βr phosphorylation, the activation of phosphoinositide 3-kinase (PI3K), pyruvate dehydrogenase kinase isozyme 1 (PDK1), and mammalian target of rapamycin (mTOR). We found that PDGF-BB induced AKT binding to actin, and that Tβ4 prevented this effect. Tβ4 also prevented the activation of freshly isolated HSC cultured in the presence of Dulbecco's modified Eagle's medium or Dulbecco's minimal essential medium containing 10% fetal bovine serum. In conclusion, overall, our findings suggest that Tβ4 by sequestering actin prevents binding of AKT, thus inhibiting its phosphorylation. Therefore, Tβ4 has the potential to be an antifibrogenic agent.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The treatment of liver fibrosis induced by hepatocyte growth factor-directed, ultrasound-targeted microbubble destruction in rats

OBJECTIVE

The purpose of this study was to explore the feasibility of using ultrasound-targeted microbubble destruction to treat liver fibrosis induced by hepatocyte growth factor (HGF).

METHODS

Forty Wistar rats were divided into five groups after the models of liver fibrosis were prepared: (1) HGF, ultrasound, and microbubbles (HGF+US/MB); (2) HGF and ultrasound (HGF+US); (3) HGF and microbubbles (HGF+MB); (4) HGF (HGF); and (5) model alone (MA). All rats were killed after being transfected for 14 days. Recovery of the liver was detect by diffusion-weighted imaging (DWI) and pathological methods. Collagen I expression was detected by immunohistochemistry. Hepatocyte growth factor expression in the liver was detect by western blotting.

RESULTS

The results of DWI and pathological examination showed the recovery of liver in HGF+US/MB group were better than those of other groups. In HGF+US/MB group, collagen I expression was less, and HGF protein was the highest among all the groups.

CONCLUSIONS

Ultrasound-targeted microbubble destruction could deliver HGF into the fibrotic liver and produce an antifibrosis effect, which could provide a novel strategy for gene therapy of liver fibrosis.