Over-expression of uPA increases risk of liver injury in pAAV-HBV transfected mice.
ABSTRACT: To investigate the relationship between over-expression of urokinase plasminogen activator (uPA) and hepatitis B virus (HBV) related liver diseases in a transgenic mouse model.Albumin-tetracycline reverse transcriptional activator and tetO-uPA transgenic mice were generated respectively through pronuclear injection and crossed to produce the double transgenic in-alb-uPA mice, for which doxycycline (Dox)-inducible and liver-specific over-expression of uPA can be achieved. Hydrodynamic transfection of plasmid adeno-associated virus (AAV)-1.3 HBV was performed through the tail veins of the Dox-induced in-alb-uPA mice. Expression of uPA and HBV antigens were analyzed through double-staining immunohistochemical assay. Cytokine production was detected by enzyme linked immunosorbent assay and ?-fetoprotein (AFP) mRNA level was evaluated through real-time quantitative polymerase chain reaction.Plasmid AAV-1.3 HBV hydrodynamic transfection in Dox-induced transgenic mice not only resulted in severe liver injury with hepatocarcinoma-like histological changes and hepatic AFP production, but also showed an increased serum level of HBV antigens and cytokines like interleukin-6 and tumor necrosis factor-?, compared with the control group.Over-expression of uPA plays a synergistic role in the development of liver injury, inflammation and regeneration during acute HBV infection.
Project description:We have used homozygous albumin enhancer/promoter-driven urokinase-type plasminogen activator/severe combined immunodeficient (uPA/SCID) mice as hosts for chimeric mice with humanized livers. However, uPA/SCID mice show four disadvantages: the human hepatocytes (h-heps) replacement index in mouse liver is decreased due to deletion of uPA transgene by homologous recombination, kidney disorders are likely to develop, body size is small, and hemizygotes cannot be used as hosts as more frequent homologous recombination than homozygotes. To solve these disadvantages, we have established a novel host strain that has a transgene containing albumin promoter/enhancer and urokinase-type plasminogen activator cDNA and has a SCID background (cDNA-uPA/SCID). We applied the embryonic stem cell technique to simultaneously generate a number of transgenic lines, and found the line with the most appropriate levels of uPA expression-not detrimental but with a sufficiently damaged liver. We transplanted h-heps into homozygous and hemizygous cDNA-uPA/SCID mice via the spleen, and monitored their human albumin (h-alb) levels and body weight. Blood h-alb levels and body weight gradually increased in the hemizygous cDNA-uPA/SCID mice and were maintained until they were approximately 30 weeks old. By contrast, blood h-alb levels and body weight in uPA/SCID chimeric mice decreased from 16 weeks of age onwards. A similar decrease in body weight was observed in the homozygous cDNA-uPA/SCID genotype, but h-alb levels were maintained until they were approximately 30 weeks old. Microarray analyses revealed identical h-heps gene expression profiles in homozygous and hemizygous cDNA-uPA/SCID mice were identical to that observed in the uPA/SCID mice. Furthermore, like uPA/SCID chimeric mice, homozygous and hemizygous cDNA-uPA/SCID chimeric mice were successfully infected with hepatitis B virus and C virus. These results indicate that hemizygous cDNA-uPA/SCID mice may be novel and useful hosts for producing chimeric mice for use in future long-term studies, including hepatitis virus infection analysis or drug toxicity studies.
Project description:RNAseq analysis of liver tissue samples from uninfected (n=5) and HBV-infected (n=5) humanized chimeric liver (uPA/SCID) mice was performed to identify potential new host factors and pathways modulated by HBV infection Overall design: Human liver-chimeric uPA/SCID mice were generated by PhoenixBio Co., Ltd. (Higashi-Hiroshima, Japan). Human hepatocytes were derived from donor BD195 (BD Biosciences, Woburn, MA). Mice containing human hepatocytes with a mean estimated replacement index of 86% (range 83-90%), calculated based on the blood concentration of human albumin [h-Alb]), were infected with 1x105 copies/mouse of HBV genotype C and followed for eight weeks to establish persistent infection of the human hepatocytes in the chimeric liver. At baseline (day 0 post-infection), mean body weights across all randomized mice were 18.0 g (19.0 - 21.1 g) with average serum levels of h-Alb of 10.0 mg/mL (9.2 - 11.9 mg/mL). Throughout the infection, all mice maintained a body weight of more than 90% of the initial level (HBV-inoculated group ranged from 90% (17.6 g) to 110% (21.6 g) to that in the control group) and an average blood h-Alb concentration of more than 10 mg/mL (HBV-inoculated group ranged from 90% (9.7 mg/mL) to 110% (11.9 mg/mL) to that in the control group).
Project description:Mouse models of liver injury provide useful tools for studying hepatocyte engraftment and proliferation. A representative model of liver injury is the albumin-urokinase (Alb-uPA) transgenic model, but neonatal lethality hampers its widespread application. To overcome this problem, we generated a transgenic mouse in which transcription of the reverse tetracycline transactivator was (rtTA) driven by the mouse albumin promoter, and backcrossed the rtTA mice onto severe combined immunodeficient (SCID)/bg mice to generate immunodeficient rtTA/SCID mice. We then produced recombinant adenoviruses Ad.TRE-uPA, in which the urokinase was located downstream of the tetracycline response element (TRE). The rtTA/SCID mouse hepatocytes were then infected with Ad.TRE-uPA to establish an inducible liver injury mouse model. In the presence of doxycycline, uPA was exclusively expressed in endogenous hepatocytes and caused extensive liver injury. Enhanced green fluorescent protein-labeled mouse hepatocytes selectively repopulated the rtTA/SCID mouse liver and replaced over 80% of the recipient liver mass after repeated administration of Ad.TRE-uPA. Compared with the original uPA mice, rtTA/SCID mice did not exhibit problems regarding breeding efficiency, and the time window for transplantation was flexible. In addition, we could control the extent of liver injury to facilitate transplantation surgery by regulating the dose of Ad.TRE-uPA. Our inducible mouse model will be convenient for studies of hepatocyte transplantation and hepatic regeneration, and this system will facilitate screening for potential genetic factors critical for engraftment and proliferation of hepatocytes in vivo.
Project description:To investigate whether HBsAg intrauterine exposure affected the offspring's immune response against HBV and the relevant mechanism, the difference of fetal liver tissue transcriptome between the C57BL/6 mice and C57BL/6-Tg (HBV Alb-1) Bri44 HBV transgenic mice was analyzed. Overall design: The difference of fetal liver tissue transcriptome between the C57BL/6 mice and C57BL/6-Tg (HBV Alb-1) Bri44 HBV transgenic mice was analyzed.
Project description:Adeno-associated virus (AAV)-mediated RNA interference shows promise as a therapy for chronic hepatitis B virus (HBV) infection, but its low efficacy and hepatotoxicity pose major challenges. We have generated AAV vectors containing different promoters and a panel of HBV-specific short hairpin RNAs (shRNAs) to investigate factors that contribute to the efficacy and pathogenesis of AAV-mediated RNA interference. HBV transgenic mice injected with high doses of AAV vectors containing the U6 promoter produced abundant shRNAs, transiently inhibited HBV, but induced severe hepatotoxicity. Sustained HBV suppression without liver toxicity can be achieved by lowering the dose of AAV-U6 vectors. AAVs containing the weaker H1 promoter did not cause liver injury, but their therapeutic efficacy was highly dependent on the sequence of the shRNA. Mice treated with the toxic U6-promoter-driven shRNA showed little change in hepatic microRNA levels, but a dramatic increase in hepatic leukocytes and inflammatory cytokines and chemokines. Hepatotoxicity was completely absent in immunodeficient mice and significantly alleviated in wild-type mice depleted of macrophages and granulocytes, suggesting that host inflammatory responses are the major cause of liver injury induced by the overexpressed shRNAs from AAV-U6 vectors. Our results demonstrate that selection of a highly potent shRNA and control its expression level is critical to achieve sustained HBV suppression without inducing inflammatory side effects.
Project description:Hepatitis B virus (HBV) infects hepatocytes specifically and causes immune-mediated liver damage. How HBV interacts with the innate immunity at the early phase of infection, either with hepatocytes or other cells in the liver, remains controversial. To address this question, we utilized various human cell-culture models and humanized Alb-uPA/SCID mice. All these models were unable to mount an interferon (IFN) response despite robust HBV replication. To elucidate the mechanisms involved in the lack of IFN response, we examined whether HBV actively inhibits innate immune functions of hepatocytes. By treating HBV-infected cells with known inducers of the IFN signaling pathway, we observed no alteration of either sensing or downstream IFN response by HBV. We showed that the DNA innate sensing pathways are poorly active in hepatocytes, consistent with muted innate immune recognition of HBV. Upon exposure to high-level HBV, human macrophages could be activated with increased inflammatory cytokine expressions. CONCLUSION:HBV behaves like a "stealth" virus and is not sensed by, nor actively interferes with, the intrinsic innate immunity of infected hepatocytes. Macrophages are capable of sensing HBV, but require exposure to high HBV titers, potentially explaining the long "window period" during acute infection and HBV's propensity to chronic infection. (Hepatology 2017;66:1779-1793).
Project description:Fetal liver progenitor cell suspensions (FLPC) and hepatic precursor cells derived from embryonic stem cells (ES-HPC) represent a potential source for liver cell therapy. However, the relative capacity of these cell types to engraft and repopulate a recipient liver compared with adult hepatocytes (HC) has not been comprehensively assessed. We transplanted mouse and human HC, FLPC, and ES-HPC into a new immunodeficient mouse strain (Alb-uPA(tg(+/-))Rag2(-/-)gamma(c)(-/-) mice) and estimated the percentages of HC after 3 months. Adult mouse HC repopulated approximately half of the liver mass (46.6 +/- 8.0%, 1 x 10(6) transplanted cells), whereas mouse FLPC derived from day 13.5 and 11.5 post conception embryos generated only 12.1 +/- 3.0% and 5.1 +/- 1.1%, respectively, of the recipient liver and smaller cell clusters. Adult human HC and FLPC generated overall less liver tissue than mouse cells and repopulated 10.0 +/- 3.9% and 2.7 +/- 1.1% of the recipient livers, respectively. Mouse and human ES-HPC did not generate HC clusters in our animal model. We conclude that, in contrast to expectations, adult HC of human and mouse origin generate liver tissue more efficiently than cells derived from fetal tissue or embryonic stem cells in a highly immunodeficient Alb-uPA transgenic mouse model system. These results have important implications in the context of selecting the optimal strategy for human liver cell therapies.
Project description:Using a hepatitis B virus (HBV) transgenic mouse model, we previously showed that a single dose of double-stranded adeno-associated virus (dsAAV) vector serotype 8 carrying a small hairpin RNA (shRNA) effectively reduces HBV replication and gene expression, but the effect gradually decreases with time. In this report, we compared the anti-HBV RNA interference (RNAi) effect of dsAAV8 with those of dsAAV7 and dsAAV9, two other hepatotropic AAV vectors, and examined whether the sequential use of these heterologous AAV vectors could prolong the anti-HBV effect. Our results showed that shRNA delivered by each of the three dsAAV vectors profoundly reduced the serum HBV titer and liver HBV mRNA and DNA levels in the transgenic mice for up to 22 weeks, with dsAAV8 having the greatest inhibitory effect, followed by dsAAV9 and dsAAV7. The potency of dsAAV8 correlated with the presence of higher levels of vector DNA and anti-HBV shRNA in the liver. An in vivo cross-administration experiment showed that preexisting anti-AAV8 antibody completely blocked the anti-HBV RNAi effect of dsAAV8, but had no effect on the potency of dsAAV7 and dsAAV9. Moreover, we demonstrated that a longer anti-HBV effect could be achieved by the sequential use of dsAAV8 and dsAAV9. These results indicate that effective and persistent HBV suppression might be achieved by a combination of the power of RNAi silencing effect and multiple treatments with different AAV serotypes.Molecular Therapy (2009) 17 2, 352-359 doi:10.1038/mt.2008.245.
Project description:Therapeutic vaccination against chronic hepatitis B must overcome high viral antigen load and local regulatory mechanisms that promote immune-tolerance in the liver and curtail hepatitis B virus (HBV)-specific CD8 T cell immunity. Here, we report that therapeutic heterologous HBcore-protein-prime/Modified-Vaccinia-Virus-Ankara (MVA-HBcore) boost vaccination followed by CpG-application augmented vaccine-induced HBcAg-specific CD8 T cell-function in the liver. In HBV-transgenic as well as AAV-HBV-transduced mice with persistent high-level HBV-replication, the combination of therapeutic vaccination with subsequent CpG-application was synergistic to generate more potent HBV-specific CD8 T cell immunity that improved control of hepatocytes replicating HBV.
Project description:BACKGROUND:Hemophilia A, a bleeding disorder resulting from F8 mutations, can only be cured by gene therapy. A promising strategy is CRISPR-Cas9-mediated precise insertion of F8 in hepatocytes at highly expressed gene loci, such as albumin (Alb). Unfortunately, the precise in vivo integration efficiency of a long insert is very low (~?0.1%). RESULTS:We report that the use of a double-cut donor leads to a 10- to 20-fold increase in liver editing efficiency, thereby completely reconstituting serum F8 activity in a mouse model of hemophilia A after hydrodynamic injection of Cas9-sgAlb and B domain-deleted (BDD) F8 donor plasmids. We find that the integration of a double-cut donor at the Alb locus in mouse liver is mainly through non-homologous end joining (NHEJ)-mediated knock-in. We then target BDDF8 to multiple sites on introns 11 and 13 and find that NHEJ-mediated insertion of BDDF8 restores hemostasis. Finally, using 3 AAV8 vectors to deliver genome editing components, including Cas9, sgRNA, and BDDF8 donor, we observe the same therapeutic effects. A follow-up of 100 mice over 1 year shows no adverse effects. CONCLUSIONS:These findings lay the foundation for curing hemophilia A by NHEJ knock-in of BDDF8 at Alb introns after AAV-mediated delivery of editing components.