A Limited Number of Transducible Hepatocytes Restricts a Wide-Range Linear Vector Dose Response in Recombinant Adeno-Associated Virus-Mediated Liver Transduction

Nakai, Hiroyuki; Thomas, Clare E.; Storm, Theresa A.; Fuess, Sally; Powell, Stephen Joseph; Wright, J. Fraser; Kay, Mark A.

doi:10.1128/jvi.76.22.11343-11349.2002

Cited by 89 publications

(96 citation statements)

References 35 publications

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“…43,44 The decrease in Z-AAT in both in vitro and in vivo assays suggested that rAAV-3X-siRNA may be potent enough to decrease Z-AAT protein expression to a level similar to or lower than that observed in heterozygous PI*MZ individuals. These individuals do not experience severe AAT liver disease as observed in homozygous PI*ZZ patients.…”

Section: Discussionmentioning

confidence: 99%

In vivo post-transcriptional gene silencing of α-1 antitrypsin by adeno-associated virus vectors expressing siRNA

Cruz

Mueller

Cossette

et al. 2007

Laboratory Investigation

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a-1 Antitrypsin (AAT) deficiency is one of the most common genetic diseases in North America, with a carrier frequency of approximately 4% in the US population. Homozygosity for the most common mutation (Glu342Lys, PI*Z) leads to the synthesis of a mutant protein, which accumulates and polymerizes within hepatocytes rather than being efficiently secreted. This lack of secretion causes severe serum deficiency predisposing to chronic lung disease. Twelve to fifteen percent of patients with PI*ZZ also develop liver disease, which can be severe, even in infancy. This is thought to be due to toxic effects of the accumulated mutant Z-AAT within the hepatocyte. Thus, an approach to reduce AAT-deficient liver disease will likely require some mechanism to decrease the amount of Z-AAT within hepatocytes. In this report, we describe studies of small-interfering RNAs (siRNAs) designed to downregulate endogenous AAT within hepatocytes. Three different siRNA sequences were identified and cloned into a recombinant adeno-associated virus (rAAV) backbone, either singly or as a trifunctional (3X) construct. Each had activity independently, but the levels of AAT expression in cell culture models showed the greatest decrease with the 3X construct, resulting in levels that were five-fold lower than controls. The rAAV-3X-siRNA was then packaged into AAV8 capsids and used in vivo to transduce the livers of human Z-AAT overexpressing transgenic mice. Those studies showed a decrease in total human AAT, a clearing of Z-AAT accumulation by immunohistochemistry, and a decrease in monomer Z-AAT within the liver within 3 weeks after vector injection. The rAAV8-3X-siRNA vector may hold promise as a potential therapy for patients with AAT liver disease.

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Section: Discussionmentioning

confidence: 99%

In vivo post-transcriptional gene silencing of α-1 antitrypsin by adeno-associated virus vectors expressing siRNA

Cruz

Mueller

Cossette

et al. 2007

Laboratory Investigation

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“…However, neutralizing antibodies against AAV2 exist in a large human population, 22,23 and relative transduction efficiency of AAV2 in liver is less than 10% in hepatocytes. 24 Nevertheless, the existence of alternative AAV serotypes, which showed distinct transduction profiles in terms of tissue tropism, may circumvent these two shortcomings and expand the usefulness of AAV. In particular, the recently isolated AAV serotype 8, which showed low pre-existing immunity in the human population, and its preferred tropism to liver, might become the top priority for future AAV applications in liver.…”

Section: Introductionmentioning

confidence: 99%

Administration-route and gender-independent long-term therapeutic correction of phenylketonuria (PKU) in a mouse model by recombinant adeno-associated virus 8 pseudotyped vector-mediated gene transfer

2005

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Phenylketonuria (PKU) is an inborn error of metabolism caused by deficiency of the hepatic enzyme phenylalanine hydroxylase (PAH) which leads to high blood phenylalanine (Phe) levels and consequent damage of the developing brain with severe mental retardation if left untreated in early infancy. The current dietary Phe restriction treatment has certain clinical limitations. To explore a long-term nondietary restriction treatment, a somatic gene transfer approach in a PKU mouse model (C57Bl/6-Pah enu2 ) was employed to examine its preclinical feasibility. A recombinant adenoassociated virus (rAAV) vector containing the murine Pah-cDNA was generated, pseudotyped with capsids from AAV serotype 8, and delivered into the liver of PKU mice via single intraportal or tail vein injections. The blood Phe concentrations decreased to normal levels (p100 mM or 1.7 mg/dl) 2 weeks after vector application, independent of the sex of the PKU animals and the route of application. In particular, the therapeutic long-term correction in females was also dramatic, which had previously been shown to be difficult to achieve. Therapeutic ranges of Phe were accompanied by the phenotypic reversion from brown to black hair. In treated mice, PAH enzyme activity in whole liver extracts reversed to normal and neither hepatic toxicity nor immunogenicity was observed. In contrast, a lentiviral vector expressing the murine Pah-cDNA, delivered via intraportal vein injection into PKU mice, did not result in therapeutic levels of blood Phe. This study demonstrates the complete correction of hyperphenylalaninemia in both males and females with a rAAV serotype 8 vector. More importantly, the feasibility of a single intravenous injection may pave the way to develop a clinical gene therapy procedure for PKU patients.

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“…In the preliminary study, we examined the transduction efficiency with different dosages of AAV by means of intraportal injection and found that dosage higher than 5 3 10 11 could not increase transduction efficiency, presumably because of the saturated liver transduction 20 ; thus the dosage of 5 3 10 11 particles was used for the experiments through the whole study. To analyze genetransfer efficiency, liver samples were collected at 2, 28, 60 and 11 particles of AAVangiostatin viruses.…”

Section: Long-term and Persistent Expression Of Angiostatin Localizedmentioning

confidence: 99%

Antiangiogenic therapy enhances the efficacy of transcatheter arterial embolization for hepatocellular carcinomas

Jiang

Meng

Tan

et al. 2007

Intl Journal of Cancer

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Transcatheter arterial embolization (TAE) is a well-established technique for unresectable hepatic malignancies. However, TAE can temporally halt the growth of hepatic tumors by blocking their arterial supply, but often tumors rapidly develop collateral blood vessels via angiogenesis. We have previously demonstrated that intraportal delivery of adeno-associated viral particles expressing angiostatin leads to long-term expression of angiostatin capable of inhibiting angiogenesis and suppressing the outgrowth of tumors in the liver. Thus, we hypothesize that adeno-associated virus (AAV)-mediated antiangiogenic therapy could enhance the efficacy of TAE to combat liver cancers. To achieve this objective, we engineered a recombinant AAV vector encoding rat angiostatin. Intraportal delivery of this vector led to long term and stable transgenic expression of angiostatin locally in rat hepatocytes and suppressed the growth of CBRH7919 hepatocellular carcinomas established in rat livers by inhibiting formation of neovessels. Although TAE therapy led to necrosis of liver tumors and suppressed their growth, the neovessels of tumors were rapidly reformed 3 weeks after TAE. However, intraportal injection of AAV-angiostatin inhibited the angiogenesis stimulated by TAE, synergized with TAE in suppressing growth of tumors established in livers and prolonged the survival of rats. In conclusion, these encouraging results warrant future investigation of the use of antiangiogenic therapy for enhancing the therapeutic efficacy of TAE to treat unresectable liver cancers. ' 2007 Wiley-Liss, Inc.Key words: hepatocellular carcinoma; transcatheter arterial embolization; angiogenesis; adeno-associated virus; angiostatin; gene therapy Hepatocellular carcinoma (HCC) is one of the most common malignancies in the world with an estimated incidence of more than one million new cases per year.1,2 HCC has a very poor prognosis with less than a 6% 5-year survival rate. Only surgery offers a cure, but liver resection is feasible for less than 15% of patients, and recurrence rates remain high after tumor resection.3 Chemotherapy and radiotherapy offer unsatisfactory response rates. Therefore, new strategies to combat HCC are urgently needed.The application of transcatheter arterial embolization (TAE) to treat liver cancers has developed conceptually based on the observation that both primary and secondary liver tumors derive their blood supply mainly from the hepatic artery, 4 while blood supply to normal liver mainly depends on the portal system. 5,6 Thus, artery obstruction by embolization can cause extensive ischemic tumor necrosis, which provides the rational for its wide use as a standard treatment for unresectable HCC. 7,8 However, the effectiveness of TAE in treating HCC is debatable as any beneficial results are short-lived because collateral arterial circulations rapidly develop. It has been reported that TAE enhances the rate of intrahepatic and extrahepatic metastases, and even results in a shorter survival.9-11 Recanalization of the embo...

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A Limited Number of Transducible Hepatocytes Restricts a Wide-Range Linear Vector Dose Response in Recombinant Adeno-Associated Virus-Mediated Liver Transduction

Cited by 89 publications

References 35 publications

In vivo post-transcriptional gene silencing of α-1 antitrypsin by adeno-associated virus vectors expressing siRNA

In vivo post-transcriptional gene silencing of α-1 antitrypsin by adeno-associated virus vectors expressing siRNA

Administration-route and gender-independent long-term therapeutic correction of phenylketonuria (PKU) in a mouse model by recombinant adeno-associated virus 8 pseudotyped vector-mediated gene transfer

Antiangiogenic therapy enhances the efficacy of transcatheter arterial embolization for hepatocellular carcinomas

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