Near Completely Humanized Liver in Mice Shows Human-Type Metabolic Responses to Drugs

Tateno, Chise; Yoshizane, Yasumi; Saito, Naomi; Kataoka, Mikiko; Utoh, Rie; Yamasaki, Chihiro; Tachibana, Asato; Soeno, Yoshinori; Asahina, Kinji; Hino, Hiroshi; Asahara, Toshimasa; Yokoi, Tsuyoshi; Furukawa, Toshinori; Yoshizato, Katsutoshi

doi:10.1016/s0002-9440(10)63352-4

Cited by 514 publications

(616 citation statements)

References 23 publications

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“…Many recent publications have unambiguously demonstrated the value of humanized mouse livers for the study of drug metabolism and hepatitis research [7][8][9]21,[23][24][25][26][27][28][29] . However, the albumin-uPA transgenic mouse used for these studies has several major practical limitations.…”

Section: Discussionmentioning

confidence: 99%

“…It was suggested that human complement produced by the donor hepatocytes injured recipient kidneys 7 . We therefore observed several (n = 3) highly repopulated mice for 4 months off NTBC.…”

Section: Repopulation Of Frg Mouse Liver With Human Hepatocytesmentioning

confidence: 99%

“…In all of these reports, the animals used were immunodeficient transgenics that express uroplasminogen activator (uPA) under the transcriptional control of an albumin promoter, rendering it hepatotoxic [5][6][7][8][9] . Although engraftment levels of up to 70% have been reported in these models, the system has several major disadvantages that have prevented its widespread use.…”

mentioning

confidence: 99%

“…Although engraftment levels of up to 70% have been reported in these models, the system has several major disadvantages that have prevented its widespread use. These include poor breeding efficiency, a narrow time window for transplantation and renal disease in repopulated mice 7 . Thus, a more robust model of humanizing mouse liver is desirable.…”

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confidence: 99%

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Robust expansion of human hepatocytes in Fah−/−/Rag2−/−/Il2rg−/− mice

et al. 2007

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Mice that could be highly repopulated with human hepatocytes would have many potential uses in drug development and research applications. The best available model of liver humanization, the uroplasminogen-activator transgenic model, has major practical limitations. To provide a broadly useful hepatic xenorepopulation system, we generated severely immunodeficient, fumarylacetoacetate hydrolase (Fah)-deficient mice. After pretreatment with a urokinaseexpressing adenovirus, these animals could be highly engrafted (up to 90%) with human hepatocytes from multiple sources, including liver biopsies. Furthermore, human cells could be serially transplanted from primary donors and repopulate the liver for at least four sequential rounds. The expanded cells displayed typical human drug metabolism. This system provides a robust platform to produce high-quality human hepatocytes for tissue culture. It may also be useful for testing the toxicity of drug metabolites and for evaluating pathogens dependent on human liver cells for replication.The liver is the principal site for the metabolism of xenobiotic compounds, including medical drugs. Because many hepatic enzymes are species specific, it is necessary to evaluate the metabolism of candidate pharmaceuticals using cultured primary human hepatocytes 1,2 . Today, hepatocytes are isolated primarily from cadaveric organs and then shipped to the location where testing will be performed. The condition (viability and state of differentiation) of hepatocytes from cadaveric sources is highly variable, and many cell preparations are of marginal quality. The availability of high-quality human hepatocytes is further hampered by the fact that they cannot be substantially expanded in tissue culture 3,4 . Hepatocytes from readily available mammalian species, such as the mouse, are not suitable for drug testing because they have a different complement of metabolic enzymes and

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Section: Discussionmentioning

confidence: 99%

“…It was suggested that human complement produced by the donor hepatocytes injured recipient kidneys 7 . We therefore observed several (n = 3) highly repopulated mice for 4 months off NTBC.…”

Section: Repopulation Of Frg Mouse Liver With Human Hepatocytesmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Robust expansion of human hepatocytes in Fah−/−/Rag2−/−/Il2rg−/− mice

et al. 2007

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“…Finally, the efficacy of human hepatocyte engraftment is highly variable in these animals, ranging from around 2% 73 to 92% after additional treatment with an antibody to asialo-GM-1. 74 Nevertheless, the chimeric uPA mouse model has proven to be useful in studies to determine the efficacy of antiviral compounds. A genotype-dependent antiviral IFN effect in chimeric mice has been observed by several groups.…”

Section: Small-animal Models For Hcv Infectionmentioning

confidence: 99%

Experimental models for hepatitis C viral infection

Boonstra¹,

Laan²,

Vanwolleghem³

et al. 2009

Hepatology

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Hepatitis C virus (HCV) infection is a leading cause of chronic liver disease. The majority of infected individuals develop a persistent infection, which is associated with a high risk of liver cirrhosis and hepatocellular carcinoma. Since its discovery 20 years ago, progress in our understanding of this virus has been suboptimal due to the lack of good model systems. However, in the past decade this has greatly accelerated with the development of various in vitro cell culture systems and in vivo small-animal models. These systems have made a major impact on the field of HCV research, and have provided important breakthroughs in our understanding of HCV infection and replication. Importantly, the in vitro cell culture systems and the small-animal models have allowed preclinical testing of numerous novel antiviral compounds for the treatment of chronic HCV infection. In this article, we give an overview of current models, discuss their limitations, and provide future perspectives for research directed at the prevention and cure of hepatitis C. (HEPATOLOGY 2009;50:1646-1655.) Hepatitis C Virus Pathology and BiologyThe hepatitis C virus (HCV) is considered a successful pathogen in establishing persistent infections by evading the immune system. Only a fraction of acutely infected individuals are able to clear the infection spontaneously, whereas about 80% of the infected individuals develop a chronic infection. 1,2 The symptoms are initially mild in these persistently infected patients, and it may take decades before the serious consequences of chronic HCV infection become apparent. Patients with chronic HCV are at increased risk for developing liver fibrosis, cirrhosis, and/or hepatocellular carcinoma. Currently, these longterm complications of chronic HCV infection are the leading indication for liver transplantation. 3,4 Because of the high incidence of new infections by blood transfusions in the 1980s before discovery of the virus, and because morbidity associated with chronic HCV infections generally takes decades to develop, it is expected that the burden of disease in the near future will rise dramatically.HCV is an enveloped flavivirus, with a positivestranded RNA genome of approximately 9600 nucleotides and is composed of a single open reading frame, which encodes a polyprotein precursor of approximately 3000 amino acids. The coding region is flanked by 5Ј and 3Ј noncoding regions, which are important for the regulation of genomic duplication as well as initiation of translation. The single polyprotein is cleaved by host and viral proteases into individual structural and nonstructural (NS) proteins (Fig. 1A). Replication of the HCV genome involves the synthesis of a full-length negative-stranded RNA intermediate, which in turn provides a template for the de novo production of positive-stranded RNA. Both these synthesis steps are mediated by the viral RNA-dependent RNA polymerase NS5B. 5-7 NS5B lacks proofreading abilities, and this leads to a high mutation rate and the generation of numerous quasispecies. ...

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Cytochrome P450 ( CYP ) Gene Superfamily

Nelson¹,

Nebert²

2011

Encyclopedia of Life Sciences

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Cytochrome P450 , which was first named a ‘pigment in the cell’ having an absorption maximum of 450 nm when reduced and bound to carbon monoxide, was thought to be a single enzyme in the early 1960s. P450 was correlated with drug and steroid metabolism by the late 1960s and recognised eventually to comprise an ancient gene superfamily encoding numerous ubiquitous enzymes that participate in countless essential life processes. More than 12 000 P450 genes are named across all kingdoms of life. Nearly all eukaryotes require sterols in their membranes for essential fluidity and lipid‐packing characteristics. CYP51 is the sterol 14α‐demethylase that makes these sterols; thus, it is fundamental to eukaryotic life. Cytochromes P450 evolved novel functions in chordates leading to the origin of steroid hormones. In conjunction with steroid hormone receptors, these novel regulatory pathways distinguish chordates from other animals. Defects in many of the 57 human functional CYP genes are involved in some inborn errors of metabolism and other clinical diseases. Key Concepts: Cytochromes P450 (CYPs) are haeme‐containing membrane proteins in the endoplasmic reticulum (ER) or mitochondrial inner membrane. Most CYPs require a source of electrons from an electron transfer chain to function: NADPH‐cytochrome P450 oxidoreductase (POR) in the ER and ferredoxin (FDX) plus ferredoxin reductase (FDXR) in mitochondria. CYP functions can be divided into oxidation/reduction of endogenous or exogenous compounds (e.g. drugs, chemicals, pollutants, etc.). Endogenous P450 substrates are mainly lipids including steroids, lanosterol, bile acids, vitamin D, retinoic acid, eicosanoids, fatty acids and some haeme breakdown products. In 2010, 13 of 57 human P450s remain as orphans without known substrates. Cytochromes P450 in humans (and most vertebrates) are divided into 18 CYP gene families based on sequence similarity. Polymorphism in CYP genes can alter a person's ability to metabolise drugs (poor, intermediate, efficient or ultra‐rapid metaboliser). CYP2D6 and CYP3A4 are the major drug‐metabolising enzymes in humans. CYP2D6 appears to be the most polymorphic. Alterations in CYP drug metabolism are often responsible for adverse drug reactions – especially when multiple drugs are taken. The triazole antifungal drugs ketoconazole, fluconazole and itraconazole target the fungal CYP51 required for fungal sterol biosynthesis. Drug resistance may occur by mutations in this gene.

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Near Completely Humanized Liver in Mice Shows Human-Type Metabolic Responses to Drugs

Cited by 514 publications

References 23 publications

Robust expansion of human hepatocytes in Fah−/−/Rag2−/−/Il2rg−/− mice

Robust expansion of human hepatocytes in Fah−/−/Rag2−/−/Il2rg−/− mice

Experimental models for hepatitis C viral infection

Cytochrome P450 ( CYP ) Gene Superfamily

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