Liposome-mediated extracellular superoxide dismutase gene delivery protects against acute liver injury in mice

KRT17 Promotes the Activation of HSCs via EMT in Liver Fibrosis

BACKGROUND AND AIMS

Although activation of hepatic stellate cells (HSCs) plays a central role in the development of liver fibrosis, the mechanism underlying the activation of HSCs remains unclear. Keratin 17 (KRT17), a member of the intermediate filament family, can regulate tumor cell proliferation and migration. The current study aimed to elucidate the role of KRT17 in the activation of HSCs and the mechanisms underlying liver fibrosis.

METHODS

The expression of KRT17 was determined using immunohistochemistry in tissue microarray. Western blotting and qRT-PCR assays were used to determine the KRT17 expression in fibrotic liver tissues obtained from human subjects and mice. LX-2 cells were treated with TGF-β1 recombinant protein and adipocyte differentiation mixture (MDI) mix to induce and reverse LX-2 cell activation, respectively, in order to explore the correlation between KRT17 and HSC activation. Additionally, cell proliferation and migration abilities of LX-2 cells transfected with KRT17-overexpressing plasmid or small interfering RNA were determined using CCK-8, flow cytometry, Transwell, and wound healing assays. Finally, rescue assay was used to explore the role of KRT17 in HSC activation and epithelial-mesenchymal transition (EMT).

RESULTS

The expression of KRT17 was higher in the human and mouse fibrotic liver tissues than in healthy liver tissues, and it was positively correlated with HSC activation. Upregulated KRT17 enhanced proliferation, migration, HSC activation and EMT in LX-2 cells, while knockdown of KRT17 reversed these effects. TGF-β1 recombinant protein accelerated KRT17-mediated EMT, HSC activation and proliferation, while TGF-β1 inhibitor counteracted the effect of KRT17 in vitro.

CONCLUSIONS

KRT17 promoted HSC activation, proliferation and EMT in hepatic fibrosis probably via TGF-β1 signaling, and KRT17 might serve as a therapeutic target for the treatment of liver fibrosis.

SOD3 deficiency induces liver fibrosis by promoting hepatic stellate cell activation and epithelial-mesenchymal transition

Hepatic stellate cell (HSC) activation plays an important role in the pathogenesis of liver fibrosis, and epithelial-mesenchymal transition (EMT) is suggested to potentially promote HSC activation. Superoxide dismutase 3 (SOD3) is an extracellular antioxidant defense against oxidative damage. Here, we found downregulation of SOD3 in a mouse model of liver fibrosis induced by carbon tetrachloride (CCl4 ). SOD3 deficiency induced spontaneous liver injury and fibrosis with increased collagen deposition, and further aggravated CCl4 -induced liver injury in mice. Depletion of SOD3 enhanced HSC activation marked by increased α-smooth muscle actin and subsequent collagen synthesis primarily collagen type I in vivo, and promoted transforming growth factor-β1 (TGF-β1)-induced HSC activation in vitro. SOD3 deficiency accelerated EMT process in the liver and TGF-β1-induced EMT of AML12 hepatocytes, as evidenced by loss of E-cadherin and gain of N-cadherin and vimentin. Notably, SOD3 expression and its pro-fibrogenic effect were positively associated with sirtuin 1 (SIRT1) expression. SOD3 deficiency inhibited adenosine monophosphate-activated protein kinase (AMPK) signaling to downregulate SIRT1 expression and thus involving in liver fibrosis. Enforced expression of SIRT1 inhibited SOD3 deficiency-induced HSC activation and EMT, whereas depletion of SIRT1 counteracted the inhibitory effect of SOD3 in vitro. These findings demonstrate that SOD3 deficiency contributes to liver fibrogenesis by promoting HSC activation and EMT process, and suggest a possibility that SOD3 may function through modulating SIRT1 via the AMPK pathway in liver fibrosis.

Antioxidant and C5a-blocking strategy for hepatic ischemia-reperfusion injury repair

BACKGROUND

Nonspecific liver uptake of nanomaterials after intravenous injection has hindered nanomedicine for clinical translation. However, nanomaterials' propensity for liver distribution might enable their use in hepatic ischemia-reperfusion injury (IRI) repair. During hepatic IRI, reactive oxygen species (ROS) are generated and the fifth component of complement (C5a) is activated. In addition, C5a is confirmed to exacerbate the vicious cycle of oxidative stress and inflammatory damage. For these reasons, we have investigated the development of nanomaterials with liver uptake to scavenge ROS and block C5a for hepatic IRI repair.

RESULTS

To achieve this goal, a traditional nanoantioxidant of nanoceria was surface conjugated with the anti-C5a aptamers (Ceria@Apt) to scavenge the ROS and reduce C5a-mediated inflammation. High uptake of Ceria@Apt in the liver was confirmed by preclinical positron emission tomography (PET) imaging. The clinical symptoms of hepatic IRI were effectively alleviated by Ceria@Apt with ROS scavenging and C5a blocking in mice model. The released pro-inflammatory cytokines were significantly reduced, and subsequent inflammatory reaction involved in the liver was inhibited.

CONCLUSIONS

The synthesized Ceria@Apt has great potential of medical application in hepatic IRI repair, which could also be applied for other ischemic-related diseases.

Oral delivery of antioxidant enzymes for effective treatment of inflammatory disease

Oral administration of protein is very challenging for therapeutic applications due to its instability and easy degradation in the gastrointestinal tract. Herein, we reported an approach to encapsulate native anti-inflammatory proteins in wind chimes like cyclodextrin (WCC) for efficient oral protein delivery. The amphiphilic WCC can self-assemble into nanoparticles in aqueous solution and achieve superior encapsulation of two antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT) by simply mixing with protein solution, avoiding any extra cumbersome steps that might inactivate protein. WCC nanovehicles can effectively protect enzyme activity and enhance their intracellular delivery. SOD and CAT co-loaded WCC nanoparticles (SC/WCC) can integrate the synergistic effect of SOD and CAT for enhancing the removal of reactive oxygen species (ROS), effectively inhibit the inflammatory response by reducing the secretion of proinflammatory factors and protect cells from ROS-induced oxidative damage. In the mouse colitis model, SC/WCC administered orally was able to efficiently accumulate in the inflamed colon, significantly inhibited the expression of proinflammatory mediators and notably alleviated the symptoms related to colitis. Therefore, we believe that the strategies we described here may provide a convenient and powerful platform for the treatment of other inflammatory diseases.

Virus-Mimicking Liposomal System Based on Dendritic Lipopeptides for Efficient Prevention Ischemia/Reperfusion Injury in the Mouse Liver

Hepatic ischemia-reperfusion injury (IRI) is a pathophysiological and huge challenge during liver surgical procedures. Herein, virus-mimicking liposomal system based on dendritic lipopeptides for efficient prevention of IRI is reported. These virus-mimicking liposomes not only have virus-like nanostructures and components, but also possess virus-like infections to liver tissue, liver cells, and organelles. The distinguished features for prevention of IRI of viral mimics are as follows: (i) viral envelope-like structure to help avoid the host immune system; (ii) well-defined nanostructure and surface to improve the accumulated efficiency in liver tissue; (iii) viral capsids mimic to enhance liver cell uptake and achieve mitochondrial targeting. This type of virus-mimicking design makes prevention of IRI by drug-loading greatly exceed the control groups with high biocompatibility and facile manufacturing.

Hepalatide ameliorated progression of nonalcoholic steatohepatitis in mice

BACKGROUND

No FDA-approved medications are available for the treatment of nonalcoholic steatohepatitis (NASH). The present study aimed to assess the effects of Hepalatide, a sodium taurocholate cotransporting polypeptide (NTCP) receptor-binding agent, on metabolic and histopathologic changes of a mouse model of NASH caused by high fat/calorie diet plus high fructose/glucose in drinking water (HFCD-HF/G) for 16 weeks.

METHODS

Male mice were randomly divided into 4 groups: controls (normal diet), HFCD-HF/G group, HFCD-HF/G plus low or high dose of Hepalatide (20 or 60 mg/kg, LH or HH, s.c. from 9 to 16 weeks).

RESULTS

Compared to HFCD-HF/G-fed mice, serum triglyceride and cholesterol levels in mice fed HFCD-HF/G plus LH or HH were decreased. The treatment with Hepalatide decreased serum alanine aminotransferase levels significantly. Liver histology and TUNEL staining showed that Hepalatide remarkably attenuated inflammation, hepatocellular steatosis and apoptosis. Hepalatide treatment decreased fasting blood glucose, serum insulin and HOMA insulin resistance index in the HH group. Moreover, Masson's staining, semi-quantitative score of fibrosis, and hydroxyproline content demonstrated that Hepalatide mitigated fibrotic progression in this murine NASH model. Additionally, most components of liver and few serum bile acids were increased in mice treated with HH.

CONCLUSION

Hepalatide effectively alleviated the pathological process, metabolic profile, hepatocellular steatosis and injury, insulin resistance, halted hepatic fibrotic progression in a mouse model of NASH, most likely through the increase of serum bile acids.

Ceria Nanoparticles Meet Hepatic Ischemia-Reperfusion Injury: The Perfect Imperfection

The mononuclear phagocyte system (MPS, e.g., liver, spleen) is often treated as a "blackbox" by nanoresearchers in translating nanomedicines. Often, most of the injected nanomaterials are sequestered by the MPS, preventing their delivery to the desired disease areas. Here, this imperfection is exploited by applying nano-antioxidants with preferential liver uptake to directly prevent hepatic ischemia-reperfusion injury (IRI), which is a reactive oxygen species (ROS)-related disease. Ceria nanoparticles (NPs) are selected as a representative nano-antioxidant and the detailed mechanism of preventing IRI is investigated. It is found that ceria NPs effectively alleviate the clinical symptoms of hepatic IRI by scavenging ROS, inhibiting activation of Kupffer cells and monocyte/macrophage cells. The released pro-inflammatory cytokines are then significantly reduced and the recruitment and infiltration of neutrophils are minimized, which suppress subsequent inflammatory reaction involved in the liver. The protective effect of nano-antioxidants against hepatic IRI in living animals and the revealed mechanism herein suggests their future use for the treatment of hepatic IRI in the clinic.

Characterization of a murine nonalcoholic steatohepatitis model induced by high fat high calorie diet plus fructose and glucose in drinking water

There are varieties of murine models of nonalcoholic steatohepatitis (NASH) with different pathophysiologic characteristics. For preclinical assessment, a standardized model would allow comparisons of various pharmacotherapeutic candidates in efficacy, pharmacokinetics, pharmaco-metabolism, and adverse effects under a same system. The present study aims to characterize murine NASH models by comparing end-points of major abnormalities. NASH was induced by feeding high fructose/glucose in drinking water (HF/G), high-fat/calorie diet (HFCD), and in combination (HFCD-HF/G) in mice for 8 or 16 weeks. HF/G feeding caused a minimal fat accumulation and increase in free fatty acids (FFA). In contrast, HFCD-HF/G feeding resulted in a remarkable increase in body weight, subcutaneous and visceral adipose tissue, macrosteatosis with a nearly seven-fold increase in triglyceride and FFA content, accompanied with marked hepatocellular injury, inflammatory responses, fibrosis, and insulin resistance, and represented as typical NASH in histopathology, metabolic, and adipokine profiles in a progressive manner. Meanwhile, mice fed HFCD displayed significant steatosis, necroptosis, fibrosis, insulin resistance, metabolic, and adipokine profiles, and the extent is less than those fed HFCD-HF/G. Significant MCP-1, CCR-2, and NLRP-1/3 activation were found in mice fed HFCD and HFCD-HF/G for 16 weeks, whereas gene expression of CPT-1 and ACOX-1 was down-regulated in these two groups in comparison to the controls. Nuclear receptors, such as SREBP-1c, FXR, LXR-α, PPAR-α, and PPAR-γ, were strikingly elevated in the HFCD-HF/G group. In conclusion, feeding HFCD-HF/G resulted in a reliable NASH model in mice with remarkable necroptosis, steatosis, fibrosis, and insulin resistance as well as a disordered profile of lipid metabolism and adipokine, and HFCD caused significant NASH features in histopathology and metabolic profiles only at a late stage. Whereas HF/G feeding barely led to minimal fat accumulation, some changes at molecular levels and metabolic disturbance in mice.

Hedgehog signaling pathway affects the sensitivity of hepatoma cells to drug therapy through the ABCC1 transporter

The poor response to drug therapy often seen in hepatocellular carcinoma requires insight into the molecular interplay responsible for intrinsic or acquired drug resistance. We previously demonstrated that the CD133^-/EpCAM^- subpopulation of the Huh-7 hepatoma cell line features aberrant activation of the hedgehog signaling (Hh) pathway and chemoresistance. The prevailing hypothesis of the present study is that hedgehog signaling may govern expression of ATP-binding cassette (ABC) transporters, which are responsible for drug resistance in the CD133^-/EpCAM^- subpopulation. Our aim is to reveal the molecular interplay in the mediation of drug resistance with a newly established Huh-7 subpopulation featuring high Hh signaling activity and drug resistance. In this study, chemoresistance was determined in a newly established Huh-7-DN subpopulation featuring the CD133^-/EpCAM^- surface marker profile, aberrant expression of Hh pathway, and epithelial-mesenchymal transition (EMT). Expression of ABC transporter proteins (ABCB1, ABCC1, and ABCG2) and Hh transcription factor Gli-1/2 was evaluated with and without Hh signaling antagonists LDE225 or itraconazole. We found that hedgehog signaling activity as determined by transfection with a Gli-Lux reporter cassette and gene expression levels tended to increase from Huh-7 CD133⁺/EpCAM⁺ to CD133^-/EpCAM^-, and the highest levels were found in Huh-7-DN cells. The Huh-7-DN subpopulation exhibited characteristics of EMT as evidenced by increased expression of vimentin and loss of E-cadherin. Sorafenib significantly inhibited the viability of all subpopulations except the Huh-7-DN subpopulation. Compared with other sorafenib-sensitive subpopulations, the Huh-7-DN subpopulation showed enhanced expression of Hh transcription factor Gli-2 and ABCC1 transporter protein. Silencing Gli-2 by lentivirus harboring shRNA against Gli-2 or LDE225 significantly suppressed expression of Gli-2 and ABCC1 genes in Huh-7-DN subpopulation. In conclusion, aberrant hedgehog signaling activation is linked to poor differentiation, epithelial-mesenchymal transition, and chemoresistance in the Huh-7-DN subpopulation. Hedgehog signaling transcription factor Gli-2 appears to be the primary regulator for drug sensitivity of hepatoma through the ABCC1 transporter.

Genetic polymorphisms in antioxidant enzyme genes and susceptibility to hepatocellular carcinoma in Chinese population: a case-control study

An increased oxidant burden has been implicated in hepatocarcinogenesis, and several antioxidant enzymes counteract potential oxidative damage. So, polymorphisms in the genes encoding antioxidant enzymes may play an important role in the development of hepatocellular carcinoma (HCC). To test this hypothesis, we investigated the association of polymorphisms in antioxidant enzyme genes, including three superoxide dismutases (SODs), catalase (CAT), and glutathione peroxidase (GPx), with HCC in a Chinese population consisting of 434 HCC patients and 480 control subjects. Genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Odds ratios (ORs) and 95 % confidence intervals (95 % CIs) were estimated by unconditional logistic regression. For the ECSOD Ala40Thr polymorphism, a significant association was observed between this polymorphism and HCC risk in non-hepatitis B virus (HBV) carriers but not in HBV carriers, and individuals with one 40Thr allele (Ala/Thr genotype) (OR = 2.13, 95 % CI = 1.25-3.64, P = 0.006) or at least one 40Thr allele (Ala/Thr and Thr/Thr genotype) (OR = 1.90, 95 % CI = 1.15-3.15, P = 0.012) showed significantly higher risk to HCC, compared with Ala/Ala genotype. No significant associations were observed between three other polymorphisms (MnSOD Ala16Val, CAT-262C/T, GPx Pro198Leu) and HCC susceptibility in both HBV carriers and non-HBV carriers. Furthermore, no other signs of combined effects, except for a combined effect of ECSOD Ala40Thr and MnSOD Val16Ala in non-HBV carriers, were observed for each combination of these four polymorphisms. In conclusion, our results indicate that the antioxidant enzyme gene polymorphisms at least partially contribute to the susceptibility to HCC.

Tumor necrosis factor-alpha-induced reduction of glomerular filtration rate in rats with fulminant hepatic failure

The mechanism of renal failure during fulminant hepatic failure (FHF) or end-stage of liver disease is not fully understood. The present study aims to delineate the mechanisms of decreased glomerular filtration rate (GFR) in acute hepatic failure. A rat model of renal insufficiency in severe liver injury was established by lipopolysaccharide (LPS) plus D-galactosamine (GalN) exposure. GFR was evaluated by continuous infusion of fluorescein isothiocyanate-inulin with implanted micro-osmotic pumps. GalN/LPS intoxication resulted in severe hepatocyte toxicity as evidenced by liver histology and biochemical tests, whereas renal morphology remained normal. GFR was reduced by 33% of the controls 12 h after GalN/LPS exposure, accompanied with a decreased serum sodium levels, a marked increase in serum TNF-α and ET-1 levels as well as significantly upregulated renal type 1 inositol 1,4,5-trisphosphate receptor (IP3R1) expression. The upregulated IP3R1 expression was abrogated by the treatment of anti-TNF-α antibodies, but not by 2-aminoethoxydiphenylborate (2-APB), which blocks the inositol 1,4,5-trisphosphate signaling pathway. Treatments with either TNF-α antibodies or 2-APB also significantly improved the compromised GFR, elevated serum urea nitrogen and creatinine levels, and reversed the decrease in glomerular inulin space and the increase in glomerular calcium content in GalN/LPS-exposed rats. The extent of acute liver injury as reflected by serum ALT levels was much more attenuated by anti-TNF-α antibodies than by 2-APB. Liver histology further confirmed that anti-TNF-α antibodies conferred better protection than 2-APB in GalN/LPS-exposed rats. LPS-elicited TNF-α over-production is responsible for decreased GFR through IP3R1 overexpression, and the compromised GFR resulted in the development of acute renal failure in rats with FHF.

A novel mouse model of nonalcoholic steatohepatitis with significant insulin resistance

Currently available models insufficiently reflect the pathogenic alternation of nonalcoholic steatohepatitis\NASH), such as insulin resistance. The present study aimed to characterize a novel NASH model caused by feeding the diet containing conjugated linoleic acid (CLA). In this study, mice were fed a control diet or the diet containing 0.5% CLA for 8 weeks. The insulin tolerance test (ITT) and homeostasis model assessment of insulin resistance (HOMA-IR) were used to determine the extent of insulin resistance. Liver lipotoxicity and inflammation were assessed by endoplasmic reticulum (ER) stress, autolipophagy, recruitment of Kupffer cells and hepatic stellate cell (HSC) activation. We found that liver weight was markedly increased, and histopathological examination showed marked macrosteatosis with focal hepatocellular death through apoptosis, and mild pericellular fibrosis with Kupffer cell recruitment and HSC activation, as well as light chain IIIβ-positive cells and enhanced ER stress in mice fed the CLA-containing diet. Enhanced synthesis and reduced β-oxidation of fatty acids resulted in their accumulation and lipotoxicity in hepatocytes. A biophotonic technology revealed lipid droplet accumulation in the liver from mice fed the CLA-containing diet, and Raman spectroscopic analysis indicated that these lipid droplets predominantly contained saturated fatty acids. Elevated fasting insulin levels, abnormal ITT and HOMA-IR confirmed the marked insulin resistance in these mice. Decreased phosphorylation of the insulin-signaling molecule Akt was partially responsible for the significant insulin resistance. In conclusion, Mice fed the diet containing CLA-developed steatohepatitis with marked insulin resistance, which is similar to the characteristics observed in NASH patients. The further characterization of this model would be particularly useful for revealing the critical role of insulin resistance in NASH development in conditions such as metabolic syndrome, diabetes and obesity.

Zein-based oral drug delivery system targeting activated macrophages

Reactive oxygen species (ROS) play an important role in the pathogenesis of rheumatoid arthritis (RA). ROS such as hydrogen peroxide and superoxide are overproduced by activated macrophages in RA. As scavengers of ROS, enzymatic proteins such as catalase and superoxide dismutase (SOD) have a great therapeutic potential; however, in vivo application is limited especially when they are orally administered. Although, the oral route is the most convenient for drug administration, therapeutic proteins are easily degraded in vivo by the harsh conditions of gastrointestinal (GI) tract. Here, we introduce a novel drug delivery system composed of zein, a plant storage protein derived from maize. We demonstrate that zein nanoparticles can protect therapeutic proteins, catalase and SOD, from the harsh conditions of GI tract. Folate-conjugated catalase or SOD in zein nanoparticles can target the activated macrophages and scavenge the ROS generated by macrophages in vitro. This novel drug delivery system will be applicable to other orally administered treatments based on the protective property in the harsh conditions of GI tract.

Therapeutic effect of liposomal-N-acetylcysteine against acetaminophen-induced hepatotoxicity

BACKGROUND

Acetaminophen (APAP) is an antipyretic analgesic drug that when taken in overdose causes depletion of glutathione (GSH) and hepatotoxicity. N-acetylcysteine (NAC) is the antidote of choice for the treatment of APAP toxicity; however, due to its short-half-life repeated dosing of NAC is required.

PURPOSE

To determine whether a NAC-loaded liposomal formulation (Lipo-NAC) is more effective than the conventional NAC in protecting against acute APAP-induced hepatotoxicity.

METHODS

Male Sprague-Dawley rats were challenged with an intragastric dose of APAP (850 mg/kg b.wt.); 4 h later, animals were administered saline, NAC, Lipo-NAC or empty liposomes and sacrificed 24 h post-APAP treatment.

RESULTS

APAP administration resulted in hepatic injury as evidenced by increases in plasma bilirubin, alanine (AST) and aspartate (ALT) aminotransferase levels and tissue levels of lipid peroxidation and myeloperoxidase as well as decreases in hepatic levels of reduced GSH, GSH peroxidase and GSH reductase. Treatment of animals with Lipo-NAC was significantly more effective than free NAC in reducing APAP-induced hepatotoxicity. Histological evaluation showed that APAP caused periacinar hepatocellular apoptosis and/or necrosis of hepatocytes around the terminal hepatic venules which was reduced by NAC treatment, the degree of reduction being greater for Lipo-NAC.

CONCLUSION

These data suggest that administration of Lipo-NAC ameliorated the APAP-induced hepatotoxicity.

SOD mimetic improves the function, growth, and survival of small-size liver grafts after transplantation in rats

BACKGROUND

Small-for-size syndrome (SFSS) may occur when graft volume is less than 45% of the standard liver volume, and it manifests as retarded growth and failure of the grafts and more mortality. However, its pathogenesis is poorly understood, and few effective interventions have been attempted.

AIMS

The present study aimed to delineate the critical role of oxidant stress in SFSS and protective effects of a superoxide dismutase mimetic, Mn(III)tetrakis(4-benzoic acid)porphyrin chloride (MnTBAP), on graft function, growth, and survival in the recipient rats.

METHODS

Small size graft liver transplantation (SSGLT) was performed to determine the survival, graft injury, and growth. MnTBAP was administered in SSGLT recipients (SSGLT+MnTBAP).

RESULTS

Serum alanine aminotransferase levels were sustained higher in SSGLT recipients, which were correlated with an increased apoptotic cell count and hepatocellular necrosis in liver sections. Malondialdehyde content, gene expression of tumor necrosis factor α and interleukin 1β, and DNA binding activity of nuclear factor-κB in the grafts were increased significantly in SSGLT recipients compared with sham-operated controls. Both phosphorylated p38 mitogen-activated protein kinase and nuclear c-Jun were increased in SSGLT. All these changes were strikingly reversed by the administration of MnTBAP, with an increase in serum superoxide dismutase activity. Moreover, in situ bromodeoxyuridine incorporation demonstrated that graft regeneration was much more profound in the SSGLT+MnTBAP group than in the SSGLT group. Finally, the survival of recipients with MnTBAP treatments was significantly improved.

CONCLUSIONS

Enhanced oxidant stress with activation of the p38/c-Jun/nuclear factor-κB signaling pathway contributes to SFSS-associated graft failure, retarded graft growth, and poor survival. MnTBAP effectively reversed the pathologic changes in SFSS-associated graft failure.

Pharmacokinetics, tissue distribution, and metabolites of a polyvinylpyrrolidone-coated norcantharidin chitosan nanoparticle formulation in rats and mice, using LC-MS/MS

A novel formulation containing polyvinylpyrrolidone (PVP) K₃₀-coated norcantharidin (NCTD) chitosan nanoparticles (PVP–NCTD–NPs) was prepared by ionic gelation between chitosan and sodium tripolyphosphate. The average particle size of the PVP–NCTD–NPs produced was 140.03 ± 6.23 nm; entrapment efficiency was 56.33% ± 1.41%; and drug-loading efficiency was 8.38% ± 0.56%. The surface morphology of NCTD nanoparticles (NPs) coated with PVP K₃₀ was characterized using various analytical techniques, including X-ray diffraction and atomic force microscopy. NCTD and its metabolites were analyzed using a sensitive and specific liquid chromatography-tandem mass spectrometry method with samples from mice and rats. The results indicated the importance of the PVP coating in controlling the shape and improving the entrapment efficiency of the NPs. Pharmacokinetic profiles of the NCTD group and PVP–NCTD–NP group, after oral and intravenous administration in rats, revealed that relative bioavailabilities were 173.3% and 325.5%, respectively. The elimination half-life increased, and there was an obvious decrease in clearance. The tissue distribution of NCTD in mice after the intravenous administration of both formulations was investigated. The drug was not quantifiable at 6 hours in all tissues except for the liver and kidneys. The distribution of the drug in the liver and bile was notably improved in the PVP–NCTD–NP group. The metabolites and excretion properties of NCTD were investigated by analyzing rat feces and urine samples, collected after oral administration. A prototype drug and two metabolites were found in the feces, and seven metabolites in the urine. The primary elimination route of NCTD was via the urine. The quantity of the parent drug eliminated in the feces of the PVP–NCTD–NP group, was 32 times greater than that of the NCTD group, indicating that the NPs dramatically increased the reduction quantity from liver to bile. We conclude that PVP–NCTD–NPs are an adequate formulation for enhancing the absorption of NCTD, and significantly improving therapeutic effects targeting the hepatic system. Decarboxylation and hydroxylation were the dominant metabolic pathways for NCTD. Metabolites were mainly excreted into rat kidney and finally into urine.

Nanotechnology for therapy and imaging of liver diseases

Nanotechnology has been considered for the improved delivery of various therapeutic agents, including drugs and genes. Indeed, liposomes and nanoparticles equipped with homing devices for the targeting of receptors over-expressed on the hepatic tissue have improved the treatment of various liver diseases. In this review, various nanotechnology approaches employed for the treatment/imaging of liver disease, either in preclinical or in clinic are discussed.

Hepatoprotective effects of IL-22 on fulminant hepatic failure induced by d-galactosamine and lipopolysaccharide in mice

Interleukin-22 (IL-22), a member of the IL-10 cytokine family that is produced by activated Th22, Th1 and Th17 cells as well as natural killer cells, plays an important role in increase of innate immunity, protection from damage and enhancement of regeneration. Here, we examined the effects of IL-22 on acute liver failure model induced by d-galactosamine (GalN) and lipopolysaccharide (LPS). Administration of recombinant human IL-22 (rhIL-22) reduced the death rate markedly and prevented mice from severe hepatic injury, as evidenced by decreased serum alanine aminotransferase (ALT) and total bilirubin (T.Bil) activity as well as improved histological signs in liver. Furthermore, IL-22 treatment decreased the hepatic malondialdehyde (MDA) contents and increased the reduced glutathione levels. Serum tumor necrosis factor α (TNF-α) level and hepatic caspase-3 activity were significantly lower in mice administrated with IL-22. Moreover, IL-22 treatment significantly enhanced activation of STAT3 and up-regulated the expression of Bcl-xL, heme oxygenase-1 (HO-1) and redox factor-1 (Ref-1) in the liver injury induced by GalN/LPS. Collectively, these data indicate that IL-22 can provide critical protection against GalN/LPS-induced liver injury through anti-apoptotic, anti-oxidant and anti-inflammatory actions.

Epithelial mesenchymal transition and hedgehog signaling activation are associated with chemoresistance and invasion of hepatoma subpopulations

BACKGROUND & AIMS

Our previous studies showed that CD133, EpCAM, and aldehyde dehydrogenase (ALDH) are useful markers to identify cancer stem cells (CSCs) in hepatocellular carcinoma (HCC) tissues. The present study aims to evaluate chemosensitivity and invasion capability of HCC based on CSC marker profiles, and to explore the underlying molecular mechanisms.

METHODS

Hepatoma cell lines were separated into subpopulations according to CD133, EpCAM, and ALDH expression profiles. Epithelial mesenchymal transition (EMT) and hedgehog (Hh) signaling were examined to identify their links with chemoresistance and aggressive invasion.

RESULTS

Well-differentiated cell lines were positive for CD133(+)/ALDH(high) and CD133(+)/EpCAM(+) at 1.5-15% and 2.3-8.3%; whereas, poorly-differentiated cells were almost all negative for these markers. FACS-enriched CD133(+)/ALDH(high) and CD133(+)/EpCAM(+) Hep3B and Huh-7 cells formed more spheroids in vitro. CD133(-)/ALDH(low) HLE cells were more resistant to cisplatin, doxorubicin or sorafenib than their positive counterparts. CD133(-)/EpCAM(-) Huh-7 cells or CD133(-)/ALDH(-) HLE cells exhibited a higher invasion rate than their positive counterparts. HLE and HLF cells acquired EMT in double negative subpopulations. Hh activity in Huh-7 CD133(-)/EpCAM(-) cells was higher than in their positive counterparts, and the inhibition of Hh activity by cyclopamine resulted in reduced cell proliferation.

CONCLUSIONS

Well-differentiated CD133(+)/ALDH(high) or CD133(+)/EpCAM(+) cells appear to be a CSC/initiating subpopulation; whereas, in poorly-differentiated hepatoma cells, EMT and enhanced hedgehog signaling activity may be responsible for their chemoresistance and invasion. These findings underscore the significance of EMT and enhanced Hh signaling in liver cancer stem or initiating cells.

Acute liver injury upregulates microRNA-491-5p in mice, and its overexpression sensitizes Hep G2 cells for tumour necrosis factor-alpha-induced apoptosis

BACKGROUND

MicroRNAs (miRNAs) have emerged as novel genetic regulators of cell functions such as proliferation, apoptosis and cancer.

AIMS

The aim of this study was to evaluate the role of a specific miRNA in modulating hepatic cell functions.

METHODS

C57Bl/6 mice were administered anti-fas receptor antibodies to induce liver cell apoptosis. miRNAs were purified from the liver tissue and evaluated using an miRNA microarray. The role of miRNA-491_5p, which was overexpressed in the model, in modulating hepatic cell functions was evaluated. miRNA-491_5p was overexpressed in Hep G2 cells, followed by the addition of tumour necrosis factor (TNF)-alpha, and induction of apoptosis as well as genes involved in apoptosis pathways were evaluated. The effect of miRNA-491_5p target genes on apoptosis was also analysed by inhibiting their expression by siRNA-induced gene silencing.

RESULTS

Upregulation of miRNA-491_5p was found in a high-dose anti-fas receptor antibody group. Overexpression of microRNA-491_5p sensitized Hep G2 cells for TNF-alpha-induced apoptosis, and also caused an inhibition of alpha-fetoprotein, (AFP), heat shock protein-90 (hsp-90) and nuclear factor-kappaB (NF-kappaB). Overexpression of miRNA-491_5p or inhibition of AFP and hsp-90 resulted in an increased apoptosis in TNF-alpha-treated Hep G2 cells.

CONCLUSIONS

One of the miRNAs that is associated with the acute liver injury mouse model, miRNA-491_5p, sensitizes Hep G2 cells for TNF-alpha-induced apoptosis, at least in part, by inhibiting AFP, hsp-90 and NF-kappaB.

Physico-chemical characterization of polylipid nanoparticles for gene delivery to the liver

Polylipid nanoparticles (PLNP) have been shown to be very effective in delivering antioxidative genes in the treatment of liver injury in mice. To build on our previous studies and to further characterize PLNP formulated from polycationic lipid (PCL) and cholesterol, we report here the synthesis of multigram quantities of PCL and employ analytical tools, such as Raman spectroscopy of single PLNP and live-cell imaging of lipofection, for the physicochemical characterization of PCL, PLNP, and the transfection process. Mass spectrometry demonstrates the characteristics of polymeric lipids. Raman spectrum of PCL reveals the polymeric structure of the polymers. The presence of cholesterol in PLNP formulation did not markedly change the Raman spectrum. PLNP-derived polyplexes exhibit Raman spectra very similar to PLNP except that the C-H out-of-plane deformation mode of the polymeric lipid is significantly suppressed, indicating the interaction with plasmid DNA. Zeta potential measurement indicates a large DNA-carrying capacity of PLNP and their stability for in vivo gene delivery. The live-cell fluorescent imaging dynamically shows that PLNP exerts transfection efficiency similar to lipofectamine in leading to early reporter gene expression in live hepatic cells. In conclusion, polylipid nanoparticles possess a high DNA carrying capacity and lipofection efficiency, rendering them suitable for testing in large animals. The employment of novel state-of-the-art technologies in the study of lipofection represents the level of physicochemical and biological characterization that is needed to best understand the key elements involved in the lipofection process.

The hepatic microcirculation: mechanistic contributions and therapeutic targets in liver injury and repair

The complex functions of the liver in biosynthesis, metabolism, clearance, and host defense are tightly dependent on an adequate microcirculation. To guarantee hepatic homeostasis, this requires not only a sufficient nutritive perfusion and oxygen supply, but also a balanced vasomotor control and an appropriate cell-cell communication. Deteriorations of the hepatic homeostasis, as observed in ischemia/reperfusion, cold preservation and transplantation, septic organ failure, and hepatic resection-induced hyperperfusion, are associated with a high morbidity and mortality. During the last two decades, experimental studies have demonstrated that microcirculatory disorders are determinants for organ failure in these disease states. Disorders include 1) a dysregulation of the vasomotor control with a deterioration of the endothelin-nitric oxide balance, an arterial and sinusoidal constriction, and a shutdown of the microcirculation as well as 2) an overwhelming inflammatory response with microvascular leukocyte accumulation, platelet adherence, and Kupffer cell activation. Within the sequelae of events, proinflammatory mediators, such as reactive oxygen species and tumor necrosis factor-alpha, are the key players, causing the microvascular dysfunction and perfusion failure. This review covers the morphological and functional characterization of the hepatic microcirculation, the mechanistic contributions in surgical disease states, and the therapeutic targets to attenuate tissue injury and organ dysfunction. It also indicates future directions to translate the knowledge achieved from experimental studies into clinical practice. By this, the use of the recently introduced techniques to monitor the hepatic microcirculation in humans, such as near-infrared spectroscopy or orthogonal polarized spectral imaging, may allow an early initiation of treatment, which should benefit the final outcome of these critically ill patients.

Norcantharidin-associated galactosylated chitosan nanoparticles for hepatocyte-targeted delivery

In this study a new chitosan (CS) derivative, galactosylated chitosan (GC), was synthesized and used to prepare norcantharidin-associated GC nanoparticles (NCTD-GC NPs) by taking advantage of the ionic cross-linkage between the molecules of the anti-hepatocarcinoma medicine NCTD and of the GC as carrier. NCTD-GC NPs were obtained with average particle size of 118.68 +/- 3.37 nm, entrapment efficiency of 57.92 +/- 0.40%, and drug-loading amount of 10.38 +/- 0.06%. Several important factors influencing the entrapment efficiency, drug-loading amount, and particle size of NCTD-GC NPs were studied. The characteristics of sustained and pH-sensitive release of NCTD from NCTD-GC NPs in vitro were studied. In addition, in vitro cellular uptake and cytotoxicity of nanoparticles to hepatoma cell lines SMMC-7721 and HepG2 were also investigated. In vitro, and compared to CS-based NCTD-CS NPs, NCTD-GC NPs demonstrated satisfactory compatibility with hepatoma cells and strong cytotoxicity against hepatocellular carcinoma cells. In vivo antitumor activity of NCTD-GC NPs was evaluated in mice bearing H22 liver tumors. NCTD-GC NPs displayed tumor inhibition effect in mice, better than either the free NCTD or the NCTD-CS NPs. As a hepatocyte-targeting carrier, GC NPs are potentially promising for clinical applications.

FROM THE CLINICAL EDITOR

In this paper, a galactosylated chitosan (GC), was synthesized and norcantharidin (NCTD)-associated galactosylated chitosan nanoparticles (NCTDGC NPs) were generated by coupling NCTD--an anti-hepatocarcinoma drug--and GC as carrier. Compared to chitosan nanoparticles, NCTD-GC-NPs demonstrated satisfactory compatibility with hepatoma cells and strong cytotoxicity against the cells.

Role of purines on hepatic ischemia-reperfusion lesions in rabbit

In this work, we evaluate the effects of adenosine 5' triphosphate (ATP) on hepatic lesions caused by ischemia/reperfusion (I/R) in liver rabbit. Rabbits were pretreated with ATP (15 mg/kg IV) or saline solution 0.9% (SS), before the hepatic I/R procedure. We evaluated the effects of ATP on hepatic injury before and after I/R. The warm hepatic I/R procedure caused profound acute liver injury, as indicated by elevated serum aspartate aminotransferase, alanine aminotransferase, and lactic dehydrogenase levels, as well as a high apoptotic cell count. All these changes were attenuate by ATP treatment before the hepatic I/R procedure. These results suggested that ATP exerted protective effects on hepatic I/R lesions in the rabbit. This ATP effect may be related to improved energy metabolism during reperfusion in ischemic livers protecting against functional damage of cellular and subcellular membranes during lipid peroxidation.

Current status of a hepatitis C vaccine: Encouraging results but significant challenges ahead

Persistent hepatitis C virus (HCV) infection affects 170 million people worldwide. Acute HCV infection is often asymptomatic, but many infected individuals develop persistent infections that may lead to development of end-stage liver diseases, including liver cirrhosis and hepatocellular carcinoma. Thus, an HCV vaccine that could significantly lower the chronicity rate would have a major impact on the disease burden. Unfortunately, HCV is a highly mutable virus, and escape mutations can undermine vaccine-induced virus-specific immunity. Also, HCV exists as multiple genotypes, and so genotype-specific vaccines might be required to achieve broad protection. Finally, vaccine development has been hampered by the lack of a small animal model and cell culture systems, but these are currently being established. Despite these obstacles, several vaccine candidates tested in the chimpanzee HCV model have shown some encouraging results.

Antioxidant enzyme gene transfer for ischemic diseases

The balance of redox is pivotal for normal function and integrity of tissues. Ischemic insults occur as results of a variety of conditions, leading to an accumulation of reactive oxygen species (ROS) and an imbalanced redox status in the tissues. The oxidant stress may activate signaling mechanisms provoking more toxic events, and eventually cause tissue damage. Therefore, treatments with antioxidants, free radical scavengers and their mimetics, as well as gene transfer approaches to overexpress antioxidant genes represent potential therapeutic options to correct the redox imbalance. Among them, antioxidant gene transfer may enhance the production of antioxidant scavengers, and has been employed to experimentally prevent or treat ischemic injury in cardiovascular, pulmonary, hepatic, intestinal, central nervous or other systems in animal models. With improvements in vector systems and delivery approaches, innovative antioxidant gene therapy has conferred better outcomes for myocardial infarction, reduced restenosis after coronary angioplasty, improved the quality and function of liver grafts, as well as outcome of intestinal and cerebral ischemic attacks. However, it is crucial to be mindful that like other therapeutic armentarium, the efficacy of antioxidant gene transfer requires extensive preclinical investigation before it can be used in patients, and that it may have unanticipated short- or long-term adverse effects. Thus, it is critical to balance between the therapeutic benefits and potential risks, to develop disease-specific antioxidant gene transfer strategies, to deliver the therapy with an optimal time window and in a safe manner. This review attempts to provide the rationale, the most effective approaches and the potential hurdles of available antioxidant gene transfer approaches for ischemic injury in various organs, as well as the possible directions of future preclinical and clinical investigations of this highly promising therapeutic modality.

Protective effects of apocynin and allopurinol on ischemia/reperfusion-induced liver injury in mice

AIM: To determine the effects of allopurinol, an inhibitor of xanthine oxidase, and apocynin, an inhibitor of NADPH oxidase, on oxidant stress and liver injury caused by hepatic ischemia/reperfusion (I/R) procedure in mice.

METHODS: Mice were pretreated with a xanthine oxidase inhibitor, allopurinol, or NADPH oxidase (NOX) inhibitor, apocynin before the hepatic I/R procedure. Then treated or untreated mice underwent the hepatic I/R procedure. The effects on hepatic injury and superoxide anions were determined after starting reperfusion.

RESULTS: A standard warm hepatic I/R procedure led to a marked increase in superoxide anion production as indicated by a superoxide anion tracer, MCLA. At the same time, the procedure caused profound acute liver injury, as indicated by elevated serum alanine aminotransferase and tumor necrosis factor-α levels, reduced liver glutathione levels and elevated malondialdehyde contents, as well as a high apoptotic cell count. All these changes were reversed by the use of apocynin or allopurinol prior to the hepatic I/R procedure.

CONCLUSION: Allopurinol and apocynin exerted protective effects on hepatic ischemia/reperfusion injury. The protection is associated with blocking the generation of superoxide anions during the hepatic I/R procedure by inhibiting xanthine oxidase and NADPH oxidase activity.

Extracellular superoxide dismutase (ecSOD) in vascular biology: an update on exogenous gene transfer and endogenous regulators of ecSOD

Extracellular superoxide dismutase (ecSOD) is the major extracellular scavenger of superoxide (O(2)(.-)) and a main regulator of nitric oxide (NO) bioactivity in the blood vessel wall, heart, lungs, kidney, and placenta. Involvement of O(2)(.-) has been implicated in many pathological processes, and removal of extracellular O(2)(.-) by ecSOD gene transfer has emerged as a promising experimental technique to treat vascular disorders associated with increased oxidant stress. In addition, recent studies have clarified mechanisms that regulate ecSOD expression, tissue binding, and activity, and they have provided new insight into how ecSOD interacts with other factors that regulate vascular function. Finally, studies of a common gene variant in humans associated with disruption of ecSOD tissue binding suggest that displacement of the enzyme from the blood vessel wall may contribute to vascular diseases. The purpose of this review is to summarize recent research findings related to ecSOD function and gene transfer and to stimulate other investigations into the role of this unique antioxidant enzyme in vascular pathophysiology and therapeutics.

Lentivirus-mediated superoxide dismutase1 gene delivery protects against oxidative stress-induced liver injury in mice

BACKGROUND

The exposure of liver to hepatotoxins, and their subsequent metabolism, results in increased reactive oxygen species (ROS), one of the major culprits in causing both acute liver cell injury and chronic liver diseases. The aim of this present study is to investigate the protective effects of lentiviral vector-mediated copper-zinc superoxide dismutase (LV-SOD1) gene transfer against ROS-induced cytotoxicity in Hep G2 cells and liver injury in mice.

METHODS

In vitro SOD1 efficacy was tested against two ROS-generating systems: hypoxanthine/xanthine oxidase (HX/XO) and hydroxyethyl radicals (HER), whereas in vivo SOD1 efficacy was evaluated in carbon tetrachloride (CCl4)-induced liver injury in C57BL/6 mice.

RESULTS

LV-SOD1 transduction in Hep G2 cells resulted in a significant increase in SOD activity in cell lysates, and it significantly decreased the toxicity induced by HX/XO and HER. High SOD1 expression in the liver was achieved via portal vein injection of LV-SOD1 in mice and these high levels were observed for 30 days, the length of the experiment to date. SOD1 overexpression significantly decreased the toxicity and restored liver function in the CCl4-treated mice.

CONCLUSIONS

These findings demonstrate for the first time that LV transduction led to the long-term expression of fully functional transgene expression in both in vitro and in vivo systems.

Gene modulation for treating liver fibrosis

Despite tremendous progress in our understanding of fibrogenesis, injury stimuli process, inflammation, and hepatic stellate cell (HSC) activation, there is still no standard treatment for liver fibrosis. Delivery of small molecular weight drugs, proteins, and nucleic acids to specific liver cell types remains a challenge due to the overexpression of extracellular matrix (ECM) and consequent closure of sinusoidal gaps. In addition, activation of HSCs and subsequent release of inflammatory cytokines and infiltration of immune cells are other major obstacles to the treatment of liver fibrosis. To overcome these barriers, different therapeutic approaches are being investigated. Among them, the modulation of certain aberrant protein production is quite promising for treating liver fibrosis. In this review, we describe the mechanism of antisense, antigene, and RNA interference (RNAi) therapies and discuss how the backbone modification of oligonucleotides affects their in vivo stability, biodistribution, and bioactivity. Strategies for delivering these nucleic acids to specific cell types are discussed. This review critically addresses various insights developed with each individual strategy and for multipronged approaches, which will be helpful in achieving more effective outcomes.

Role of MAPK phosphatase-1 in sustained activation of JNK during ethanol-induced apoptosis in hepatocyte-like VL-17A cells

Ethanol metabolism plays a central role in activating the mitogen-activated protein kinase (MAPK) cascade leading to inflammation and apoptosis. Sustained activation of c-Jun N-terminal kinase (JNK), one of the MAPKs, has been shown to induce apoptosis in hepatocytes. MAPK phosphatase-1 (MKP-1) has been shown to dephosphorylate MAPKs in several cells. The aim of the study is to evaluate the role of MKP-1 in sustained JNK activation as a mechanism to explain ethanol-induced hepatocyte apoptosis. VL-17A cells (HepG2 cells overexpressing alcohol dehydrogenase and cytochrome P450-2E1) were exposed to ethanol for different time periods. Western blots were performed for MKP-1, phospho-JNK, phosphotyrosine, and protein kinase Cdelta (PKCdelta). Electrophoretic mobility shift assays for AP-1 were performed. Apoptosis was measured by caspase-3 activity assay, TUNEL, and 4',6-diamidino-2-phenylindole staining. Reactive oxygen species were neutralized by overexpressing both superoxide dismutase-3 and catalase genes using lentiviral vectors in VL-17A cells. Ethanol incubation markedly decreased the MKP-1 protein levels to 15% of control levels and was associated with sustained phosphorylation of p46 JNK and p54 JNK, as well as increased apoptosis. VL-17A cells overexpressing superoxide dismutase-3 and catalase, treatment with a tyrosine kinase inhibitor, or incubation of the cells with PKCdelta small interference RNAs significantly inhibited the ethanol-induced MKP-1 degradation and apoptosis. Ethanol-induced oxidative stress enhanced the tyrosine phosphorylation of PKCdelta, which in turn caused the proteasomal degradation of MKP-1, leading to sustained JNK activation and increased apoptosis in VL-17A cells.

Targeted delivery of catalase and superoxide dismutase to macrophages using folate

Reactive oxygen species (ROS) secreted by activated macrophages play a central role in causing rheumatoid arthritis, and therapeutics that can inhibit the production of ROS by macrophages have great clinical potential. Superoxide dismutase (SOD) and catalase (CAT) are two enzymes that scavenge ROS and have great potential for treating rheumatoid arthritis. However, clinical trials with these enzymes have been ineffective, due to drug delivery problems, and effective SOD and CAT delivery vehicles are greatly needed. In this communication, we demonstrate that CAT and SOD can be effectively targeted to activated macrophages, via the folate receptor. Folate was conjugated to CAT and SOD using NHS/EDC chemistry with high efficiency. Cell culture experiments demonstrated that folate conjugation increased their ability to scavenge ROS, produced by the macrophages, and also enhanced their uptake into activated macrophages. We anticipate numerous applications of folate-conjugated CAT and SOD in treating inflammatory diseases, based on their efficacy and straightforward synthesis.

Hepatic tumor necrosis factor signaling and nuclear factor-kappaB: effects on liver homeostasis and beyond

The proinflammatory cytokine TNF has a pivotal role in liver pathophysiology because it holds the capacity to induce both hepatocyte cell death and hepatocyte proliferation. This dual effect of TNF on hepatocytes reflects its ability to induce both nuclear factor kappaB (NF-kappaB)-dependent gene expression and cell death. Multiple studies have demonstrated the crucial role of the transcription factor NF-kappaB in the decision between life and death of a hepatocyte. Massive hepatocyte apoptosis preceding embryonic lethality in NF-kappaB-deficient mice constituted the first indication of an essential antiapoptotic function of NF-kappaB in the liver. Although many studies confirmed this crucial cytoprotective role of NF-kappaB in adult liver, a number of genetic studies recently obtained conflicting results on the exact role of NF-kappaB in different mouse models of TNF hepatotoxicity, demonstrating that caution should be taken when interpreting studies using different NF-kappaB-deficient mice in distinct models of liver injury. Recent reports showing a role for hepatic NF-kappaB activation in the proliferation of malignant cells during hepatocarcinogenesis, and in the progression of fatty liver diseases to insulin resistance and type 2 diabetes mellitus demonstrate that NF-kappaB can also have more detrimental effects in the liver. Moreover, its role in the development of the metabolic syndrome emphasizes that hepatic NF-kappaB activation might also have adverse effects on the endocrine system. Therefore, understanding the regulation of hepatic TNF signaling and NF-kappaB activation is of critical therapeutic importance. In this review, we summarize how studies on the role of NF-kappaB in different mouse models of liver pathologies have contributed to this understanding.

Improvement of recipient survival after small size graft liver transplantation in rats with preischemic manipulation or administering antisense against nuclear factor-kappaB

The survival rate of small size graft liver transplantation (SSGLT) in rats is inversely related to graft volume. The present study aims to evaluate the protective effects of preischemic manipulation (PIM) and oligodeoxynucleotide (ODN) antisense against NF-kappaB on graft failure and animal survival. The protective effects of PIM and NF-kappaB ODN antisense were investigated in a rat SSGLT model. The graft function and survival of recipient animals over 3 weeks were monitored, and in situ staining for apoptotic cells in the graft tissue was examined. Both PIM and NF-kappaB antisense treatment significantly improved the survival of small graft-transplanted rats compared with the SSGLT group, lowered serum levels of alanine and aspartate aminotransferases, as well as tumor necrosis factor-alpha (TNF-alpha) levels, and minimized apoptotic cell counts in the liver sections. Moreover, the enhanced activation of NF-kappaB in the SSGLT group was diminished in both PIM and NF-kappaB antisense-treated groups. The findings suggest that enhanced NF-kappaB activation and TNF-alpha production may be involved in the ischemia/reperfusion-associated small size graft injury, and that PIM and antisense against NK-kappaB are effective in the attenuation of the small size graft injury, and improve the recipient animal survival.

Short hairpin RNA causes the methylation of transforming growth factor-beta receptor II promoter and silencing of the target gene in rat hepatic stellate cells

Small interfering RNA (siRNA) induces transcriptional gene silencing (TGS) in plant and animal cells. RNA dependent DNA methylation (RdDM) accounts for TGS in plants, but it is unclear whether siRNA induces RdDM in mammalian cells. To determine whether stable expression of short hairpin siRNA (shRNA) induces DNA methylation in mammalian cells, we transduced rat hepatic stellate SBC10 cells with lentiviral vectors which encode an U6 promoter-driven shRNA expression cassette homologous to the transforming growth factor-beta receptor (TGFbetaRII) promoter region. Sequencing analysis of bisulfite-modified genomic DNA showed the methylation of cytosine residues both in CpG dinucleotides and non-CpG sites around the target region of the TGFbetaRII promoter in SBC10 cells transduced with the promoter-targeting lentiviral vector. In these cells, real-time RT-PCR showed a decrease in TGFbetaRII mRNA levels which were reversed by treatment with 5-aza-2-deoxycytidine. Our results demonstrate that recombinant lentivirus-mediated shRNA delivery resulted in the methylation of the homologous promoter area in mammalian cells, and this approach may be used as a tool for transcriptional gene silencing by epigenetic modification of mammalian cell promoters.

Cyclic Arg-Gly-Asp peptide-labeled liposomes for targeting drug therapy of hepatic fibrosis in rats

Targeting hepatic stellate cells (HSCs) has been challenging due to the lack of specific receptors or motifs on the cells. The aim of the present study was to develop a HSC-specific system for improving drug delivery to HSCs. The affinity of a cyclic peptide containing Arg-Gly-Asp (cRGD) to collagen type VI receptor on HSCs was examined in both in vitro and in vivo experiments. Sterically stable liposomes (SSLs) were modified with this peptide to yield a new carrier, cRGD-SSL. The targeting efficiency of this carrier in delivering interferon (IFN)-alpha1b was investigated in a rat model of liver fibrosis induced by bile duct ligation (BDL). When incubating HSCs or hepatocytes with cyclic RGD peptide, the peptide was bound preferentially to activated HSCs. Biodistribution study showed that the accumulation of cRGD peptide-labeled liposomes in HSCs isolated from BDL rats was 10-fold more than unlabeled SSLs. BDL rats receiving injections of IFN-alpha1b entrapped in cRGD-SSL exhibited significantly reduced extent of liver fibrosis compared with BDL control rats or BDL rats treated with IFN-alpha1b entrapped in SSLs. Thus, cRGD-SSL is an efficient drug carrier, which selectively targets activated HSCs and improves drug therapy for liver fibrosis to a significant extent. This liposomal formulation represents a new means of targeting drug carrier for the treatment of liver fibrosis, and it may have potential clinical applications.

Delivery of antioxidative enzyme genes protects against ischemia/reperfusion-induced liver injury in mice

Hepatic ischemia/reperfusion (I/R) injury is characterized by the generation of reactive oxygen species (ROS), such as superoxide anions and hydrogen peroxide. The aim of this study is to investigate whether antioxidative gene delivery by our polylipid nanoparticles (PLNP) is an effective approach for prevention of the injury. Polyplexes of extracellular superoxide dismutase (EC-SOD) and/or catalase genes were injected via the portal vein 1 day prior to a warm I/R procedure in mice. The effects of the gene delivery were determined 6 hours after starting reperfusion. PLNP-mediated antioxidative gene delivery led to a marked increase in human EC-SOD and catalase gene expression in the liver. Liver superoxide dismutase (SOD) and catalase activity both increased approximately 10-fold. Increased liver superoxide anion levels caused by the I/R procedure were reduced to normal levels by EC-SOD gene delivery. The overexpression of these 2 antioxidative genes significantly suppressed the I/R-induced elevation of serum alanine aminotransferase (ALT) levels, decreased liver malondialdehyde content, restored glutathione reserve, and improved liver histology. In conclusion, EC-SOD or catalase gene delivery by PLNP resulted in high levels of the transgene activity in the liver, and markedly attenuated hepatic I/R injury. The protection is directly associated with elevated antioxidative enzyme activity as the result of the gene delivery. This novel approach may become a potential therapy to improve graft function and survival after liver transplantation.

Novel Action of Indoleamine 2,3-Dioxygenase Attenuating Acute Lung Allograft Injury

RATIONALE

Lung allografts are prone to reperfusion injury and acute rejection, which, in addition to infiltrating lymphocytes, are accompanied by neutrophil infiltration and neutrophil-associated oxidative stress. Indoleamine 2,3-dioxygenase (IDO) is a unique cytosolic enzyme that possesses T-cell-suppressive and antioxidant properties.

OBJECTIVES

The purpose of this study was to determine if genetic up-regulation of IDO could ameliorate acute lung allograft injury.

METHODS

Lung orthotopic transplants were performed using Lewis donors and Sprague-Dawley rat recipients (allografts) or the same strain (isografts). Plasmid-encoding human IDO was delivered to donor lungs in vivo using a nonviral gene-transfer vector, polyethylenimine. Transplanted lungs were evaluated at 6 d post-transplantation based on pulmonary function, histology, inflammatory responses, and their associated oxidative stress. Basic biology of the IDO-overexpressing lung cells was evaluated in vitro in response to external oxidant.

MEASUREMENTS AND MAIN RESULTS

This gene delivery method led to uniform transgene expression in lung tissue distributed in airway, alveolar epithelial, and endothelial cells. IDO overexpression in lung allografts resulted in a significant protective effect with improvement in functional properties (peak airway pressure and oxygenation) and histologic appearance. Although IDO was able to block local T-cell responses, it failed to abrogate neutrophilic infiltration and the inflammation-associated oxidative stress. IDO-enhanced lung cells were resistance to oxidant-induced necrosis and apoptosis by limiting intracellular reactive oxygen species formation.

CONCLUSIONS

These results demonstrate that IDO prevents acute lung allograft injury through augmenting the local antioxidant defense system and inhibiting alloreactive T-cell responses.

Molecular therapy for hepatic injury and fibrosis: Where are we?

Hepatic fibrosis is a wound healing response, involving pathways of inflammation and fibrogenesis. In response to various insults, such as alcohol, ischemia, viral agents, and medications or hepatotoxins, hepatocyte damage will cause the release of cytokines and other soluble factors by Kupffer cells and other cell types in the liver. These factors lead to activation of hepatic stellate cells, which synthesize large amounts of extracellular matrix components. With chronic injury and fibrosis, liver architecture and metabolism are disrupted, eventually manifesting as cirrhosis and its complications. In addition to eliminating etiology, such as antiviral therapy and pharmacological intervention, it is encouraging that novel strategies are being developed to directly address hepatic injury and fibrosis at the subcellular and molecular levels. With improvement in understanding these mechanisms and pathways, key steps in injury, signaling, activation, and gene expression are being targeted by molecular modalities and other molecular or gene therapy approaches. This article intends to provide an update in terms of the current status of molecular therapy for hepatic injury and fibrosis and how far we are from clinical utilization of these new therapeutic modalities.

Inhibition of hepatitis viral replication by siRNA

Small interfering RNA (siRNA)-mediated sequence-specific gene silencing is a powerful tool to inhibit endogenous and exogenous gene expression, and it holds great potential to prevent and eradicate viral infection, for which existing therapy is inadequate, such as HIV, hepatitis B virus (HBV) and hepatitis C virus (HCV). A number of studies have documented the effectiveness of siRNA against HBV or HCV at various regions of the viral genome in infected human hepatoma cell lines. Selected siRNA may reduce the production of viral replicons, as well as structural or non-structural proteins by > 90%. Only a few in vivo studies that demonstrated the efficacy of siRNA in the suppression of HBV replication in mice are available. Thus, reliable models of HBV and HCV infection in small animals or non-human primates are needed to evaluate the delivery and efficacy of siRNA as a therapeutic modality for viral hepatitis.