Prevention of bleomycin-induced pulmonary fibrosis after adenovirus-mediated transfer of the bacterial bleomycin resistance gene

Attenuation of LPS-induced acute lung injury by continentalic acid in rodents through inhibition of inflammatory mediators correlates with increased Nrf2 protein expression

Background

Acute lung injury (ALI) together with acute respiratory distress syndrome (ARDS) are associated with high rate of mortality and morbidity in patients. In the current study, the anti-inflammatory effects of continentalic acid (CNT) in LPS-induced acute lung injury model was explored.

Methods

The acute lung injury model was established by administering LPS (5 mg/kg) intraperitonealy. Following LPS administration, the survival rate, temperature changes and lung Wet/Dry ratio were assessed. The antioxidants (GSH, GST, Catalase and SOD) and oxidative stress markers (MDA, NO, MPO) were evaluated in all the treated groups. Similarly, the cytokines such as IL-1β, IL-6 and TNF-α were analyzed using ELISA assay. The histological changes were determined using H and E staining, while Nrf2 and iNOS level were determined using immunohistochemistry analysis. The molecular docking analysis was performed to assess the pharmacokinetics parameters and interaction of the CNT with various protein targets.

Results

The results showed that CNT dose dependently (10, 50 and 100 mg/kg) reduced mortality rate, body temperature and lungs Wet/Dry ratio. CNT post-treatment significantly inhibited LPS-induced production of pro-inflammatory cytokines such as IL-1β, IL-6 and TNF-α. The CNT post-treatment markedly improved the hematological parameters, while significantly reduced the MPO (indicator of the neutrophilic infiltration) activity compared to the LPS treated group. Furthermore, the CNT (100 mg/kg) post-administration remarkably inhibited the lung Wet/Dry ratio. The CNT (100 mg/kg) treated group showed marked reduction in the oxidative stress markers such as malonaldehyde (MDA) and Nitric oxide (NO) concentration, while induced the level of the anti-oxidant enzymes such as GST, GSH, Catalase and SOD. Similarly, the CNT markedly reduced the iNOS expression level, while induced the Nrf2 protein expression. Additionally, the molecular docking study showed significant binding interaction with the Nrf2, p65, Keap1, HO-1, IL-1β, IL-6, TNF-α and COX-2, while exhibited excellent physicochemical properties.

Conclusion

The CNT showed marked protection against the LPS-induced lung injury and improved the behavioral, biochemical and histological parameters. Furthermore, the CNT showed significant interaction with several protein targets and exhibited better physicochemical properties.

Low-dose paclitaxel ameliorates pulmonary fibrosis by suppressing TGF-β1/Smad3 pathway via miR-140 upregulation

Abnormal TGF-β1/Smad3 activation plays an important role in the pathogenesis of pulmonary fibrosis, which can be prevented by paclitaxel (PTX). This study aimed to investigate an antifibrotic effect of the low-dose PTX (10 to 50 nM in vitro, and 0.6 mg/kg in vivo). PTX treatment resulted in phenotype reversion of epithelial-mesenchymal transition (EMT) in alveolar epithelial cells (AECs) with increase of miR-140. PTX resulted in an amelioration of bleomycin (BLM)-induced pulmonary fibrosis in rats with reduction of the wet lung weight to body weight ratios and the collagen deposition. Our results further demonstrated that PTX inhibited the effect of TGF-β1 on regulating the expression of Smad3 and phosphorylated Smad3 (p-Smad3), and restored the levels of E-cadherin, vimentin and α-SMA. Moreover, lower miR-140 levels were found in idiopathic pulmonary fibrosis (IPF) patients, TGF-β1-treated AECs and BLM-instilled rat lungs. Through decreasing Smad3/p-Smad3 expression and upregulating miR-140, PTX treatment could significantly reverse the EMT of AECs and prevent pulmonary fibrosis of rats. The action of PTX to ameliorate TGF-β1-induced EMT was promoted by miR-140, which increased E-cadherin levels and reduced the expression of vimentin, Smad3 and p-Smad3. Collectively, our results demonstrate that low-dose PTX prevents pulmonary fibrosis by suppressing the TGF-β1/Smad3 pathway via upregulating miR-140.

Static and dynamic mechanics of the murine lung after intratracheal bleomycin

Background

Despite its widespread use in pulmonary fibrosis research, the bleomycin mouse model has not been thoroughly validated from a pulmonary functional standpoint using new technologies. Purpose of this study was to systematically assess the functional alterations induced in murine lungs by fibrogenic agent bleomycin and to compare the forced oscillation technique with quasi-static pressure-volume curves in mice following bleomycin exposure.

Methods

Single intratracheal injections of saline (50 μL) or bleomycin (2 mg/Kg in 50 μL saline) were administered to C57BL/6 (n = 40) and Balb/c (n = 32) mice. Injury/fibrosis score, tissue volume density (TVD), collagen content, airway resistance (R_N), tissue damping (G) and elastance coefficient (H), hysteresivity (η), and area of pressure-volume curve (PV-A) were determined after 7 and 21 days (inflammation and fibrosis stage, respectively). Statistical hypothesis testing was performed using one-way ANOVA with LSD post hoc tests.

Results

Both C57BL/6 and Balb/c mice developed weight loss and lung inflammation after bleomycin. However, only C57BL/6 mice displayed cachexia and fibrosis, evidenced by increased fibrosis score, TVD, and collagen. At day 7, PV-A increased significantly and G and H non-significantly in bleomycin-exposed C57BL/6 mice compared to saline controls and further increase in all parameters was documented at day 21. G and H, but not PV-A, correlated well with the presence of fibrosis based on histology, TVD and collagen. In Balb/c mice, no change in collagen content, histology score, TVD, H and G was noted following bleomycin exposure, yet PV-A increased significantly compared to saline controls.

Conclusions

Lung dysfunction in the bleomycin model is more pronounced during the fibrosis stage rather than the inflammation stage. Forced oscillation mechanics are accurate indicators of experimental bleomycin-induced lung fibrosis. Quasi-static PV-curves may be more sensitive than forced oscillations at detecting inflammation and fibrosis.

Role of proinflammatory cytokines IL-18 and IL-1beta in bleomycin-induced lung injury in humans and mice

Administration of several chemotherapeutic drugs, such as bleomycin, busulfan, and gefitinib, often induces lethal lung injury. However, the precise mechanisms responsible for this drug-induced lung injury are still unclear. In the present study, we examined the role of the proinflammatory cytokines IL-18 and IL-1beta in the mechanism of bleomycin-induced lung injury. We performed immunohistochemical analysis of IL-18 and IL-18 receptor (R) alpha chain expression in the lungs of five patients with bleomycin-induced lethal lung injury. Enhanced expression of both IL-18 and IL-18Ralpha was observed in the lungs of all five patients with bleomycin-induced lung injury. To support the data obtained from patient samples, the levels of IL-1beta and IL-18 mRNA and protein, pulmonary inflammation, and lung fibrosis were examined in mouse models of bleomycin-induced lung injury. Intravenous administration of bleomycin induced the expression of IL-1beta and IL-18 in the serum and lungs of wild-type C57BL/6 mice. IL-18-producing F4/80(+) neutrophils, but not CD3(+) T cells, were greatly increased in the lungs of treated mice. Moreover, bleomycin-induced lung injury was significantly attenuated in caspase-1(-/-), IL-18(-/-), and IL-18Ralpha(-/-) mice in comparison with control mice. Thus, our results provide evidence for an important role of IL-1beta and IL-18 in chemotherapy-induced lung injury.

IL-6 cytoprotection in hyperoxic acute lung injury occurs via suppressor of cytokine signaling-1-induced apoptosis signal-regulating kinase-1 degradation

Hyperoxic acute lung injury (HALI) is characterized by a cell death response that is inhibited by IL-6. Suppressor of cytokine signaling-1 (SOCS-1) is an antiapoptotic negative regulator of the IL-6-mediated Janus kinase-signal transducer and activator of transcription signaling pathway. We hypothesized that SOCS-1 is a critical regulator and key mediator of IL-6-induced cytoprotection in HALI. To test this hypothesis, we characterized the expression of SOCS-1 and downstream apoptosis signal-regulating kinase (ASK)-1-Jun N-terminal kinase signaling molecules in small airway epithelial cells in the presence of H(2)O(2), which induces oxidative stress. We also examined these molecules in wild-type and lung-specific IL-6 transgenic (Tg(+)) mice exposed to 100% oxygen for 72 hours. In control small airway epithelial cells exposed to H(2)O(2) or in wild-type mice exposed to 100% oxygen, a marked induction of ASK-1 and pJun N-terminal kinase was observed. Both IL-6-stimulated endogenous SOCS-1 and SOCS-1 overexpression abolished H(2)O(2)-induced ASK-1 activation. In addition, IL-6 Tg(+) mice exposed to 100% oxygen exhibited reduced ASK-1 levels and enhanced SOCS-1 expression compared with wild-type mice. Interestingly, no significant changes in activation of the key ASK-1 activator, tumor necrosis factor receptor-1/tumor necrosis factor receptor-associated factor-2 were observed between wild-type and IL-6 Tg(+) mice. Furthermore, the interaction between SOCS-1 and ASK-1 promotes ubiquitin-mediated degradation both in vivo and in vitro. These studies demonstrate that SOCS-1 is an important regulator in IL-6-induced cytoprotection against HALI.

Viral Infections of the Lung

The lungs are among the most vulnerable to microbial assault of all organs in the body. From a contemporary vantage, lower respiratory tract infections are the greatest cause of infection-related mortality in the United States, and rank seventh among all causes of deaths in the United States.2,3 From a global and historic perspective, the scope and scale of lower respiratory tract infection is greater than any other infectious syndrome, and viral pneumonias have proven to be some of the most lethal and dramatic of human diseases. The 1918–1919 influenza pandemic, perhaps the most devastating infectious disease pandemic in recorded history, resulted in an estimated 40 million deaths worldwide, including 700,000 deaths in the U.S.4 The global outbreak of severe acute respiratory syndrome (SARS) during 2003, although considerably smaller in scale, resulted in 8098 cases and 774 deaths5 and is a dramatic contemporary example of the ability of viral pneumonias to rapidly disseminate and cause severe disease in human populations.

Antisense oligonucleotide inhibition of heat shock protein (HSP) 47 improves bleomycin-induced pulmonary fibrosis in rats

Background

The most common pathologic form of pulmonary fibrosis arises from excessive deposition of extracellular matrix proteins such as collagen. The 47 kDa heat shock protein 47 (HSP47) is a collagen-specific molecular chaperone that has been shown to play a major role during the processing and/or secretion of procollagen.

Objectives

To determine whether inhibition of HSP47 could have beneficial effects in mitigating bleomycin-induced pulmonary fibrosis in rats.

Methods

All experiments were performed with 250–300 g male Wistar rats. Animals were randomly divided into five experimental groups that were administered: 1) saline alone, 2) bleomycin alone, 3) antisense HSP47 oligonucleotides alone, 4) bleomycin + antisense HSP47 oligonucleotides, and 5) bleomycin + sense control oligonucleotides. We investigated lung histopathology and performed immunoblot and immunohistochemistry analyses.

Results

In rats treated with HSP47 antisense oligonucleotides, pulmonary fibrosis was significantly reduced. In addition, treatment with HSP47 antisense oligonucleotides significantly improved bleomycin-induced morphological changes. Treatment with HSP47 antisense oligonucleotides alone did not produce any significant changes to lung morphology. Immunoblot analyses of lung homogenates confirmed the inhibition of HSP47 protein by antisense oligonucleotides. The bleo + sense group, however, did not exhibit any improvement in lung pathology compared to bleomycin alone groups, and also had no effect on HSP47 expression.

Conclusion

These findings suggest that HSP47 antisense oligonucleotide inhibition of HSP47 improves bleomycin-induced pulmonary fibrosis pathology in rats.

An antisense oligonucleotide to HSP47 inhibits paraquat-induced pulmonary fibrosis in rats

The most common cause of death from poisoning by the widely used, but highly toxic herbicide paraquat is respiratory failure from pulmonary fibrosis, which develops through pathological overproduction of extracellular matrix proteins such as the collagens. Heat shock protein (HSP47) is a collagen-specific molecular chaperone that assists in the posttranslational modifications of procollagens during collagen biosynthesis. We investigated whether treatment with an HSP47-antisense oligonucleotide would inhibit paraquat-induced pulmonary fibrosis in Wistar rats. Rats randomized into three groups (control, paraquat, and paraquat+antisense). Paraquat (20 mg/kg/day) (n=16) or a saline control (n=10) was administered to groups of Wistar rats. Intratracheal administration of the antisense oligonucleotide (100 nmol/kg in saline) was performed after the initial paraquat treatment (n=16). Treatment with paraquat alone induced pulmonary fibrosis in the entire group, while treatment with the antisense oligonucleotide alone did not produce any substantial change in lung histology. Administration of antisense oligonucleotides produced a substantial reduction in paraquat-induced pulmonary fibrosis. An immunoblot analysis confirmed that the HSP47-antisense oligonucleotide inhibited HSP47 production. These findings indicate that the HSP47-antisense oligonucleotide inhibited paraquat-induced pulmonary fibrosis and pneumopathy in rats.

Inhibitory effect of recombinant adenovirus carrying immunocaspase-3 on hepatocellular carcinoma

Previously, Srinivasula devised a contiguous molecule (C-cp-3 or immunocaspase-3) containing the small and large subunits similar to that in the active form of caspas-3 and found C-cp-3 had similar cleavage activity to the active form of caspase-3. To search for a new clinical application of C-cp-3 to treat hepatocellular carcinoma, recombinant adenoviruses carrying the C-cp-3 and a-fetoprotein (AFP) promoter (Ad-rAFP-C-cp-3) were constructed through a bacterial homologous recombinant system. The efficiency of adenovirus-mediated gene transfer and the inhibitory effect of Ad-rAFP-C-cp-3 on the proliferation of hepatocarcinoma cells were determined by X-gal stain and MTT assay, respectively. The tumorigenicity of hepatocarcinoma cells transfected by Ad-rAFP-C-cp-3 and the antitumor effect of Ad-rAFP-C-cp-3 on transplanted tumor in nude mice were detected in vivo. The results suggested that Ad-rAFP-C-cp-3 can inhibit specifically proliferation of AFP-producing human hepatocarcinoma cells in vitro and in vivo and adenovirus-mediated C-cp-3 transfer could be used as a new method to treat human hepatocarcinoma.

Introduction of antisense oligonucleotides to heat shock protein 47 prevents pulmonary fibrosis in lipopolysaccharide-induced pneumopathy of the rat

Acute respiratory distress syndrome (ARDS) confers high morbidity, and in part due to pulmonary fibrosis. The 47-kDa heat shock protein 47 (HSP 47) is a collagen-specific molecular chaperone that has been shown to play a major role in the processing and secretion of procollagen. We examined the effect of antisense oligonucleotides against HSP 47 in Wistar rats with lipopolysaccharide (LPS)-induced pulmonary fibrosis. These rats expressed heat shock protein (HSP) 47 and collagen in response to LPS. The distribution of HSP 47 was similar to that of collagen, and all control rats displayed pulmonary fibrosis after intratracheal administration of 20 mg/kg LPS alone. Antisense oligonucleotides (100 nmol/kg dissolved in saline) were administered with the LPS among experimental subjects. Subsequent immunoblot analysis confirmed the inhibition of HSP 47 by the administration of antisense oligonucleotides. The oligonucleotides significantly improved pulmonary fibrosis among those rats administered LPS, but the oligonucletides themselves did not produce any significant changes in the behavior or histology of the lungs among control rats. These findings suggest that HSP 47 antisense oligonucleotides improve lung fibrosis among rats with LPS-induced pneumopathy.

Respective roles of TNF-alpha and IL-6 in the immune response-elicited by adenovirus-mediated gene transfer in mice

The immunogenicity of recombinant adenoviruses (Ad) constitutes a major concern for their use in gene therapy. Antibody- and cell-mediated immune responses triggered by adenoviral vectors hamper long-term transgene expression and efficient viral readministration. We previously reported that interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha play an essential role in both the acute phase and antibody response against Ad, respectively. As TNF-alpha controls the immune response and the development of the immune system, we examined here the consequence of blockade of TNF-alpha activity through Ad-mediated gene delivery of a dimeric mouse TNFR1-IgG fusion protein on transgene expression from a second Ad. Ad encoding TNFR1-IgG (AdTNFR1-Ig) was injected intravenously along with Ad encoding beta-galactosidase or alpha1-antitrypsin transgene in wild-type (IL-6(+/+)) but also in IL-6-deficient mice (IL-6(-/-)) to analyze how TNF-alpha and IL-6 diminish liver gene transfer efficacy. Blockade of TNF-alpha leads to increased transgene expression in both wild-type and IL-6(-/-) mice due to a reduced inflammatory response and to diminished recruitment of macrophages and NK cells towards the liver. Antibody responses against adenoviral particles and expressed transgenes were only delayed in AdTNFR1-Ig-treated wild-type mice, but were markedly reduced in AdTNFR1-Ig-treated IL-6(-/-) mice. Finally, treatment of mice with etanercept, a clinically approved anti-TNF-alpha drug, confirmed the importance of controlling proinflammatory cytokines during gene therapy by adenoviral vectors.

In vivo IL-10 gene delivery attenuates bleomycin induced pulmonary fibrosis by inhibiting the production and activation of TGF-beta in the lung

BACKGROUND

Idiopathic pulmonary fibrosis is a devastating disorder for which there is no effective treatment. Transforming growth factor (TGF)-beta plays a critical role in provoking fibrosis. Interleukin (IL)-10 is a potent immunosuppressive cytokine but its effect on the fibrosing process is unclear. A study was undertaken to examine whether IL-10 affects the production and activation of TGF-beta and thus can attenuate the fibrosis.

METHODS

Mice were given an intratracheal injection of bleomycin. On day 1 or 14, IL-10 gene was delivered by rapid intravenous injection of Ringer's solution containing plasmid. Two weeks after the plasmid injection the mice were examined for fibrosis. The effect of IL-10 on TGF-beta production by alveolar macrophages was assessed.

RESULTS

Even when delivered during the fibrosing phase, IL-10 gene significantly suppressed the pathological findings, hydroxyproline content, and production of both active and total forms of TGF-beta1 in the lung. Immunohistochemical analyses showed that alveolar macrophages were one of the major sources of TGF-beta1 and IL-10 diminished the intensity of the staining. IL-10 also suppressed the expression of alphaV beta6 integrin, a molecule that plays an important role in TGF-beta activation, on lung epithelial cells. Alveolar macrophages from bleomycin injected mice produced TGF-beta1 spontaneously ex vivo, which was significantly suppressed by treatment of the mice in vivo or by treatment of the explanted macrophages ex vivo with IL-10.

CONCLUSION

IL-10 suppresses the production and activation of TGF-beta in the lung and thus attenuates pulmonary fibrosis, even when delivered in the chronic phase.

Inhibitory effect of recombinant adenovirus carrying melittin gene on hepatocellular carcinoma

OBJECTIVES

To search for a new clinical application of melittin (Mel): treating hepatocellular carcinoma with Mel gene.

METHODS

Recombinant adenoviruses carrying the Mel gene and alpha-fetoprotein (AFP) promoter (Ad-rAFP-Mel) were constructed through a bacterial homologous recombinant system. The efficiency of adenovirus-mediated gene transfer and the inhibitory effect of Ad-rAFP-Mel on the proliferation of hepatocarcinoma cells were determined by X-gal stain and MTT assay, respectively. The tumorigenicity of hepatocarcinoma cells transfected by Ad-rAFP-Mel and the antitumor effect of Ad-rAFP-Mel on transplanted tumor in nude mice were detected in vivo.

RESULTS

The Mel mRNA was transcribed in BEL-7402 hepatocellular carcinoma cells transducted by Ad-rAFP-Mel. The efficiency of adenovirus-mediated gene transferred to BEL-7402 cells was 100% when the multiplicity of infection of Ad-rAFP-Mel was 10 in vitro, and was also high in vivo. The inhibitive rates of Ad-rAFP-Mel and Ad-rAFP for BEL7402 cells were 66.2 +/- 2.7% and 2.9 +/- 2.3% (t=30.83, P=6.6 x 10(-6)) by MTT assay. The inhibitive rates of Ad-CMV-Mel for BEL7402, SMMC7721 and L02 cells were 58.9 +/- 9.6%, 65.9 +/- 3.8% and 31.7 +/- 1.2%, respectively, and of Ad-rAFP-Mel were 66.2 +/- 2.7%, 16.1 +/- 6.6% and 7.5 +/- 3.3%, respectively (t=1.27, P=0.27; t=11.31, P=3.5 x 10(-4); and t=12.12, P=2.7 x 10(-4) versus the Ad-CMV-Mel group in the same cells). The tumorigenicity rates of hepatocarcinoma cells transfected by Ad-rAFP-Mel were decreased. A significant antineoplastic effect was detected on transplanted tumor in nude mice by intratumoral injection of Ad-rAFP-Mel.

CONCLUSIONS

Ad-rAFP-Mel can inhibit specifically proliferation of AFP-producing human hepatocarcinoma cells in vitro and in vivo. This suggests that animal toxin gene can be used as an antitumor gene.

Imatinib mesylate inhibits the profibrogenic activity of TGF-beta and prevents bleomycin-mediated lung fibrosis

Idiopathic pulmonary fibrosis is a progressive and fatal fibrotic disease of the lungs with unclear etiology. Prior efforts to treat idiopathic pulmonary fibrosis that focused on anti-inflammatory therapy have not proven to be effective. Recent insight suggests that the pathogenesis is mediated through foci of dysregulated fibroblasts driven by profibrotic cytokine signaling. TGF-beta and PDGF are 2 of the most potent of these cytokines. In the current study, we investigated the role of TGF-beta-induced fibrosis mediated by activation of the Abelson (Abl) tyrosine kinase. Our data indicate that fibroblasts respond to TGF-beta by stimulating c-Abl kinase activity independently of Smad2/3 phosphorylation or PDGFR activation. Moreover, inhibition of c-Abl by imatinib prevented TGF-beta-induced ECM gene expression, morphologic transformation, and cell proliferation independently of any effect on Smad signaling. Further, using a mouse model of bleomycin-induced pulmonary fibrosis, we found a significant inhibition of lung fibrosis by imatinib. Thus, Abl family members represent common targets for the modulation of profibrotic cytokine signaling.

Redox-active protein thioredoxin prevents proinflammatory cytokine- or bleomycin-induced lung injury

Thioredoxin (TRX) is a multifunctional redox (reduction/oxidation)-active protein that scavenges reactive oxygen species by itself or together with TRX-dependent peroxiredoxin. TRX also has chemotaxis-modulating functions and suppresses leukocyte infiltration into sites of inflammation. Leukocyte infiltration and oxidative stress may be involved in the pathogenesis of several diseases, including interstitial lung diseases (ILD). We examined the effects of TRX in two mouse models of human ILD. Recently, we established a new mouse model for human ILD in which daily administration of proinflammatory cytokine interleukin (IL)-18 with IL-2 induces lethal lung injury accompanied by acute interstitial inflammatory responses. Administration of recombinant TRX suppressed IL-18/IL-2-induced interstitial infiltration of cells and prevented death and lung tissue damage. TRX-transgenic mice also showed resistance to lethal lung injury caused by IL-18/IL-2. Administration of bleomycin induces the infiltration of polymorphonuclear and mononuclear leukocytes in the pulmonary interstitium, followed by progressive fibrosis. Wild-type mice given recombinant TRX treatment and TRX-transgenic mice demonstrated a decrease in bleomycin-induced cellular infiltrates and fibrotic changes in the lung tissue. These results suggest that TRX modulates pulmonary inflammatory responses and acts to prevent lung injury. TRX may have clinical benefits in human ILD, including lung fibrosis, for which no effective therapeutic strategy currently exists.

Gene therapy for hepatocellular carcinoma using non-viral vectors composed of bis guanidinium-tren-cholesterol and plasmids encoding the tissue inhibitors of metalloproteinases TIMP-2 and TIMP-3

Metalloproteinases (MMPs) and their natural inhibitors (TIMPs) contribute to the regulation of tumor microenvironment. Their expressions are deregulated in almost all human cancers. We report a novel approach to gene therapy of hepatocellular carcinoma (HCC), using repeated injections of DNA plasmids encoding the tissue inhibitors of metalloproteinases (TIMPs) TIMP-2 or TIMP-3, and a novel competent formulation of gene transfer based on nontoxic cationic cholesterol derivatives. The new gene delivery system was efficient in demonstrating the antitumor efficiency of TIMP-2 or TIMP-3 in inhibiting tumor growth of human HuH7 HCC cells xenografted into nude mice. We show, for the first time, an in vivo effect of TIMP-3 in delaying HCC tumor growth. No treatment-related toxicity was noted. An inhibition of angiogenesis and tumor necrosis accompanied the inhibitory effects of TIMP-2 or TIMP-3 on tumor expansion and invasion. We also report a bystander effect produced by transfected HuH7 tumor cells mixed with untransfected cells in 1:1 ratio in culture that resulted in killing 98% of cells within 96 h. In addition, the soluble forms of TIMP-2 and TIMP-3 expressed by transfected cells exerted a cytotoxic effect on untransfected HuH7 cell cultures. Taken together, these results demonstrate the potential efficacy of repeated treatment of secreted TIMP-2 and TIMP-3 for the design of nonviral gene therapy for hepatocarcinoma.

Adenovirus-mediated transfer and overexpression of heme oxygenase 1 cDNA in lung prevents bleomycin-induced pulmonary fibrosis via a Fas-Fas ligand-independent pathway

Heme oxygenase 1 (HO-1) is an inducible enzyme that catalyzes heme to generate bilirubin, ferritin, and carbon monoxide. Because enhanced expression of HO-1 confers protection against many types of cell and tissue damage by modulating apoptotic cell death or cytokine expression profiles, we hypothesized that adenovirus-mediated transfer of HO-1 cDNA and subsequent overexpression of the protein in lung would provide therapeutic benefit in a murine model of bleomycin-induced pulmonary fibrosis. In C57BL/6 mice, HO-1 overexpression clearly suppressed the development of fibrotic changes and was associated with enhanced interferon gamma production in lung and reduced numbers of respiratory epithelial cells with damaged DNA. However, HO-1 overexpression did not prevent pulmonary fibrosis induced by agonistic anti-Fas antibody inhalation in C57BL/6 or ICR mice, a strain known to develop pulmonary fibrosis via the Fas-Fas ligand (FasL) pathway. Consistent with the concept that HO-1 overexpression prevents fibrosis via a pathway independent of Fas-FasL interaction, Ad.HO-1 administration prevented bleomycin-induced pulmonary fibrosis in gld/gld mice, which express nonfunctional FasL. These observations suggest that using HO-1 overexpression strategies to treat idiopathic pulmonary fibrosis, or fibrotic disorders of other target organs, by attenuating apoptotic cell death likely would be effective in clinical situations.

Inhibition of rat hepatocellular carcinoma tumor growth after multiple infusions of recombinant Ad.AFPtk followed by ganciclovir treatment

BACKGROUND/AIMS

The antitumor efficiency of thymidine kinase (tk) in Herpes Simplex virus-tk-based gene therapy of rat hepatocellular carcinoma (HCC) was examined by specific transcriptional targeting of tk to tumor cells by the alpha-fetoprotein (AFP) gene promoter and by multiple infusions of recombinant adenovirus Ad.AFPtk.

METHODS

We developed a surgical procedure that allows efficient, non-invasive delivery (during 2 months) of recombinant Ad via the intra-hepatic artery (IHA) route.

RESULTS

Treatment of tumor-bearing rats with either three or five doses of 5x10(9)pfu Ad.AFPtk, administered every 3 days, and followed by intra-peritoneal treatment with ganciclovir (GCV), resulted in tumor growth inhibition and apoptosis, when compared to untreated tumor-bearing rats or animals treated with Ad.AFPlacZ or buffered saline. No treatment-related toxicity was noted. Antitumor efficacy, based on tumor size and number of tumors, was demonstrated in more than 50% of Ad.AFPtk+GCV-treated rats, as compared to control rats (P<0.0005).

CONCLUSIONS

Our results demonstrate the safety and potential of multiple Ad.AFPtk administrations by the IHA route to inhibit HCC tumor growth, and support further clinical investigation of Ad.AFPtk gene therapy for treatment of multifocal tumor lesions in most primary liver cancers.

A pivotal role of cytosolic phospholipase A(2) in bleomycin-induced pulmonary fibrosis

Pulmonary fibrosis is an interstitial disorder of the lung parenchyma whose mechanism is poorly understood. Potential mechanisms include the infiltration of inflammatory cells to the lungs and the generation of pro-inflammatory mediators. In particular, idiopathic pulmonary fibrosis is a progressive and fatal form of the disorder characterized by alveolar inflammation, fibroblast proliferation and collagen deposition. Here, we investigated the role of cytosolic phospholipase A(2) (cPLA(2)) in pulmonary fibrosis using cPLA(2)-null mutant mice, as cPLA(2) is a key enzyme in the generation of pro-inflammatory eicosanoids. Disruption of the gene encoding cPLA(2) (Pla2g4a) attenuated IPF and inflammation induced by bleomycin administration. Bleomycin-induced overproduction of thromboxanes and leukotrienes in lung was significantly reduced in cPLA(2)-null mice. Our data suggest that cPLA(2) has an important role in the pathogenesis of pulmonary fibrosis. The inhibition of cPLA(2)-initiated pathways might provide a novel therapeutic approach to pulmonary fibrosis, for which no pharmaceutical agents are currently available.

Smad3 deficiency attenuates bleomycin-induced pulmonary fibrosis in mice

Transforming growth factor-beta (TGF-beta) signaling plays an important regulatory role during lung fibrogenesis. Smad3 was identified in the pathway for transducing TGF-beta signals from the cell membrane to the nucleus. Using mice without Smad3 gene expression, we investigated whether Smad3 could regulate bleomycin-induced pulmonary fibrosis in vivo. Mice deficient in Smad3 demonstrated suppressed type I procollagen mRNA expression and reduced hydroxyproline content in the lungs compared with wild-type mice treated with bleomycin. Furthermore, loss of Smad3 greatly attenuated morphological fibrotic responses to bleomycin in the mouse lungs, suggesting that Smad3 is implicated in the pathogenesis of pulmonary fibrosis. These results show that Smad3 contributes to bleomycin-induced lung injury and that Smad3 may serve as a novel target for potential therapeutic treatment of lung fibrosis.

Bilirubin ameliorates bleomycin-induced pulmonary fibrosis in rats

Many possible treatments for pulmonary fibrosis have been investigated, but except for some current clinical trials, none have succeeded in clinical trials. On the basis of the antioxidant action of bilirubin (BIL), we examined the effects of hyperbilirubinemia on the development of bleomycin (BLM)-induced pulmonary fibrosis in rats. The animals' plasma BIL level was kept within 3 and 10 mg/dl by repeated intravenous infusion of a high dose of BIL. We studied the inhibitory effects of hyperbilirubinemia on BLM-induced pulmonary fibrosis through histopathologic and biochemical analyses. Mortality of rats with BLM-induced pulmonary fibrosis was significantly lower in the three groups with hyperbilirubinemia. The ameliorating effect of hyperbilirubinemia on pulmonary fibrosis was shown by lung histology, as well as by a decreased lung content of hydroxyproline and reduced bronchoalveolar lavage fluid (BALF) concentration of transforming growth factor (TGF)-beta(1). The number of polymorphonuclear leukocytes and lymphocytes in BALF was also decreased in the groups with hyperbilirubinemia. Furthermore, oxidative metabolites of BIL in urine were present at significantly higher levels in BLM-treated rats with hyperbilirubinemia than in those without hyperbilirubinemia. These data suggest that the antioxidative action of BIL can attenuate BLM-induced pulmonary fibrosis, partly by inhibiting lung inflammation and production of TGF-beta1.

Molecular monitoring of bleomycin-induced pulmonary fibrosis by cDNA microarray-based gene expression profiling

Pulmonary fibrosis is a progressive disorder whose molecular pathology is poorly understood. Here we developed an in-house cDNA microarray ("lung chip") originating from a lung-normalized cDNA library. By using this lung chip, we analyzed global gene expression in a murine model of bleomycin-induced fibrosis and selected 82 genes that differed by more than twofold intensity in at least one pairwise comparison with controls. Cluster analysis of these selected genes showed that the expression of genes associated with inflammation reached maximum levels at 5 days after bleomycin administration, while genes involved in the development of fibrosis increased gradually up to 14 days after bleomycin treatment. These changes in gene expression signature were well correlated with observed histopathological changes. The results show that microarray analysis of animal disease models is a powerful approach to understanding the gene expression programs that underlie these disorders.

Contribution of small GTPase Rho and its target protein rock in a murine model of lung fibrosis

Excess fibroblasts and inflammatory cells may play an important role in the pathogenesis of idiopathic pulmonary fibrosis (IPF). The small GTPase, Rho, and its target protein, Rho-associated coiled-coil-forming protein kinase (ROCK), have been recognized to be major regulators of cell locomotion mediated by reorganization of the actin cytoskelton. Activated ROCK inhibits myosin phosphatase, and this in turn induces phosphorylation of the myosin light chain (MLC). To determine the mechanisms underlying the deterioration process of IPF, we investigated the effect of Y-27632, a selective ROCK inhibitor, in a murine model of bleomycin (BLM)-induced lung fibrosis. The Aschcroft score and hydroxyproline content of the BLM-treated mouse lung decreased in response to Y-27632 treatment. The number of broncoalveolar cells was decreased by Y-27632, and migration of macrophages, neutrophils, and fibroblasts in vitro was inhibited by Y-27632 regardless of various stimuli. Although expression of ROCK-II mRNA in the lung homogenates of the BLM-treated mice was increased approximately 9-fold, expression of ROCK-II protein showed only a slight tendency to increase. BLM elevated MLC phosphorylation levels, and Y-27632 inhibited BLM response. These findings indicate that the Rho/ROCK-mediated pathway plays an important role in IPF, and that blocking of this pathway leads to inhibition of IPF development.

Antisense oligonucleotides to NF-kappaB improve survival in bleomycin-induced pneumopathy of the mouse

We examined the effect of antisense oligonucleotides to the p65 subunit of NF-kappaB on the survival of bleomycin (BLM)-induced pneumonitis in C57BL/6 mice (female, 8 wk of age, 17 to 20 g body weight). Fifty-three percent and all control mice died within 6 to 9 d after intravenous administration of 150 and 300 mg/kg BLM alone, respectively. The intravenous administration of the antisense oligonucleotides (900 microgram/animal dissolved in 200 microliter saline, 6 h before and 5 d after BLM administration) significantly improved the survival rate to 100 and 40% in 150- and 300-mg/kg-treated animals, respectively. The antisense oligonucleotides also significantly improved the loss of body weight, the increase in lung hydroxyproline, and histologic changes by BLM, whereas the antisense oligonucleotides themselves did not produce any significant changes in the behavior or lung histology. Both peripheral blood monocytes and alveolar macrophages were confirmed to contain large amounts of intracellular antisense oligonucleotides after BLM injection by FITC-labeled fluorescent microscopy. Further, Western blotting confirmed the inhibition of NF-kappaB in macrophages by the antisense oligonucleotides. These findings suggest that the antisense oligonucleotides are incorporated into activated alveolar macrophages and ameleriorate the lung injury and pneumonitis/fibrosis, thereby improving the survival of BLM-induced pneumopathy in mice.

Bleomycin-induced pulmonary injury in mice deficient in SPARC

SPARC (secreted protein, acidic and rich in cysteine) is a component of the matrix that appears to regulate tissue remodeling. There is evidence that it accumulates in the lung in the setting of pulmonary injury and fibrosis, but direct evidence of its involvement is only now emerging. We therefore investigated the development of pulmonary fibrosis induced by bleomycin administered either intratracheally or intraperitoneally in mice deficient in SPARC. Bleomycin (0.15 U/mouse) given intratracheally induced significantly more pulmonary fibrosis in mice deficient in SPARC compared with that in wild-type control mice, with the mutant mice demonstrating greater neutrophil accumulation in the lung. However, in wild-type and SPARC-deficient mice given intraperitoneal bleomycin (0.8 U/injection x 5 injections over 14 days), the pattern and severity of pulmonary fibrosis, as well as the levels of leukocyte recruitment, were similar in both strains of mice. These findings suggest that the involvement of SPARC in pulmonary injury is likely to be complex, dependent on several factors including the type, duration, and intensity of the insult. Furthermore, increased neutrophil accumulation in the peritoneal cavity was also observed in SPARC-null mice after acute chemical peritonitis. Together, these data suggest a possible role for SPARC in the recruitment of neutrophils to sites of acute inflammation.

The role of IL-6 in the inflammatory and humoral response to adenoviral vectors

BACKGROUND

The major concern for the use of adenoviral vectors for gene therapy is the viral-induced immune response that has been shown to be responsible for short-term transgene expression and inefficient viral readministration. In vivo studies and clinical trials with recombinant adenovirus have suggested a role for interleukin 6 (IL-6) in the inflammatory reaction that follows Ad-infection. IL-6 plays an important role in the acute-phase innate response, in the differentiation of B-cells and in the activation of the Th2 cell subsets.

METHODS

To clarify the role of IL-6 in the immune response to Ad-vectors, we used IL-6 knock-out mice (IL-6 -/- ). E1/E3 deleted recombinant adenoviruses encoding reporter genes were administered to wild type or IL-6-/- mice; transgene expression kinetics and immune response were analyzed.

RESULTS

Acute phase protein production was significantly diminished in IL-6 -/- mice after adenoviral injection. No significant difference between wild type and knock-out animals in the level or the nature of leucocyte recruitment in the liver was detectable. A minor decrease in the IgG response to Ad-recombinants was observed in knock-out mice. Gene transfer efficiency, both in terms of levels and duration of transgene expression, were comparable in IL-6+/+ and IL-6-/- mice. An increase in IL-1beta and tumor necrosis factor-alpha (TNF-alpha) levels was observed in the sera of IL-6 -/- mice as compared to wild type animals: this phenomenon represents a possible compensatory mechanism for the establishment of the immune phenotype observed in mutant mice.

CONCLUSIONS

IL-6 plays a role in the acute phase response to adenoviral vectors. Nevertheless, possibly due to a compensatory mechanism exerted by other cytokines, the antibody and cellular responses to adenoviruses are very similar in wild type and IL-6 -/- mice.

Gene transfer to adult human lung tissue ex vivo

The potential of gene therapy for treatment of lung disease remains unrealised. Early model systems often resulted in promising efficiency of gene transfer, only to prove irreproducible in the clinic. While problems such as induction of host immune responses and duration of expression also need to be addressed, it is now widely believed that alternative, relevant models which more accurately reflect gene transfer efficiencies in human lungs are urgently required. We report here on a human lung slice culture system to assess gene transfer to adult lung epithelium. A lacZ-expressing adenovirus (AdCA35lacZ) was used as a reporter vector. A solution of AdCA35lacZ was instilled via bronchioles into resected lung tissue, a route analogous to clinical administration. Following a 1 h incubation, the tissue was inflated with a 0.4% agarose solution, instilled via the same bronchioles. Once solidified, 500 microm slices of the tissue were prepared and cultured for 4 days. beta-Galactosidase staining revealed lacZ transgene expression in bronchiolar and alveolar cells of the lung slices throughout the 4 days in culture. This system, which can also be used to study other viral and liposome vectors, could prove to be a useful alternative model for assessing gene delivery to adult human lung epithelium.

Liver sinusoidal endothelial cells are not permissive for adenovirus type 5

Adenoviral vectors are known to transduce hepatocytes in normal liver tissue with high efficiency. The aim of this study was to investigate whether sinusoidal endothelial cells, which separate hepatocytes from the bloodstream in the sinusoidal lumen, are permissive for infection by adenoviruses. We show here that microvascular liver sinusoidal endothelial cells are not infected by adenovirus type 5 in vivo or in vitro unless high MOIs are used. In contrast, macrovascular endothelial cells from aorta are efficiently infected by adenovirus type 5. In addition, Kupffer cells, similar to sinusoidal endothelial cells, are not infected by adenovirus type 5. Liver sinusoidal endothelial cells do not express the integrin receptor alpha(v)beta3, which is required for efficient infection by adenoviruses. Our results demonstrate that hepatocytes are the main cell population of the liver that is infected by adenovirus type 5.

Transient gene transfer and expression of Smad7 prevents bleomycin-induced lung fibrosis in mice

TGF-beta plays an important role in lung fibrosis, which is a major cause of suffering and death seen in pulmonary disease. Smad7 has been recently identified as an antagonist of TGF-beta signaling. To investigate whether this novel molecule can be exploited for therapy of lung fibrosis, we determined the effect of exogenous Smad7, introduced by a recombinant human type 5 adenovirus vector, on bleomycin-induced lung fibrosis in mice. C57BL/6 mice with bleomycin-induced lungs received an intratracheal injection of a recombinant adenovirus carrying mice Smad7 cDNA. These mice demonstrated suppression of type I precollagen mRNA, reduced hydroxyproline content, and no morphological fibrotic responses in the lungs when compared with mice administered adenovirus carrying Smad6 cDNA. In addition, we found that expression of Smad7 transgene blocked Smad2 phosphorylation induced by bleomycin in mouse lungs. These data indicated that gene transfer of Smad7 (but not Smad6) prevented bleomycin-induced lung fibrosis, suggesting that Smad7 may have applicability in the treatment of pulmonary fibrosis.

Lipofectamine and related cationic lipids strongly improve adenoviral infection efficiency of primitive human hematopoietic cells

Adenoviral vectors have the potential to infect a large number of cell types including quiescent cells. Their use in hematopoietic cells is limited by the episomal form of their DNA, leading to transgene loss in the progeny cells. However, the use of this vector may be interesting for short-term in vitro modifications of primitive human hematopoietic cells. Therefore, we have investigated the ability of adenovirus to transduce cord blood CD34+ cells. Several promoters were tested using the lacZ reporter gene. The PGK and CMV promoters induced transgene expression in 18-25% of the cells, whereas the HTLV-I and especially the RSV promoter were almost inactive. To improve infection efficiency, adenovirus was complexed with cationic lipids. Lipofectamine, Cellfectin, and RPR120535b, but not Lipofectin, Lipofectace, or DOTAP, markedly improved transgene expression in CD34+ cells (from 19 to 35%). Lipofectamine strongly enhanced infection efficiency of the poorly infectable primitive CD34+CD38low cells (from 11 to 28%) whereas the more mature CD34+CD38+ cells were only slightly affected (from 24 to 31%). Lipofectamine tripled the infection of CFU-GMs and LTC-ICs derived from the CD34+CD38low cell fraction (from 4 to 12% and from 5 to 16%, respectively) and doubled that of BFU-Es (from 13 to 26%). We conclude that cationic lipids can markedly increase the efficiency of adenovirus-mediated gene transfer into primitive hematopoietic cells.