New animal models for studying persistent hepatitis virus infections
Hepatotropic infections including hepatitis B (HBV) and C viruses (HCV) infect over 600 million people
worldwide and are major causative agents of liver disease including fibrosis, cirrhosis and liver cancer.
Development of more effective clinical therapies has been delayed by the lack of robust and suitable
animal models. Both HBV and HCV have an almost unique and mechanistically unexplained host tropism
limited to robust infections in humans and chimpanzees. We are pursuing three independent but
possibly complementary approaches to overcome current species barriers and generate a small animal
model for persistent HBV and HCV: 1. Adaptation of HCV and HBV genomes to infect hepatocytes of
non-human primates, with the long-term goal of a simian tropic HCV and HBV strains. 2. Humanization
of the mouse liver and immune system by transplanting human hematopoietic stem cells and
hepatocytes into a single murine recipient, thus allowing studies of pathology, immune correlates, and
mechanisms of HBV and HCV persistence. 3. Genetic host adaptation to create an inbred murine model
for HBV and HCV. Through the development and use of these platforms, we aim to shed light on HBV
and HCV molecular virology, to understand the associated liver disease, and to uncover novel avenues
for therapeutic intervention作者: 战天斗hbv 时间: 2015-3-22 19:46
Modeling human liver development, chronic hepatitis B virus infection, immunopathogenesis and
therapy in humanized mice
MT Bility1, F Li1, L Cheng1, C. Murphy1, Kouki Nio1, L Zhang2, and Lishan Su1, 2
1Department of Microbiology and Immunology, Lineberger Comprehensive Cancer Center, School of Medicine, The University
of North Carolina at Chapel Hill, NC 27599, USA; 2Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
Background: Chronic hepatitis B infection affects over 350 million individuals resulting in chronic liver
inflammation, cirrhosis and hepatocellular carcinoma. The mechanisms of chronic HBV infection and
immunopathogenesis are poorly understood, and its therapeutic option is limited, due to a lack of
relevant robust animal models.
Materials: We have recently developed novel humanized mouse models with both human immune
system and human liver cells by reconstituting highly immunodeficient mice with human hematopoietic
stem cells and liver progenitor cells (NBT-hu HSC/Hep mice). The NBT-hu HSC/Hep mouse supports
persistent HBV and HCV infection.
Results: We detect human immune responses to HBV in the spleen/LN but they are impaired in the liver.
Furthermore, we detect human liver-specific chronic liver inflammation and fibrosis/cirrhosis in the
infected humanized mice. Analysis of chronic HBV/HCV-induced liver inflammation showed high level of
infiltrated human macrophages with M2-like phenotypes. Additionally, HBV/HCV-induced M2-like
macrophages were associated with Th1 impairment and tissue fibrosis in infected animals. Importantly,
similar M2-like macrophage accumulation was confirmed in chronic hepatitis virus infected patients
with liver diseases. Furthermore, we demonstrate that HBV/HCV preferentially induced M2-related
genes in both M1 and M2 macrophages. Finally, HBV infection and its associated immunopathogenesis
were prevented by treatment with a novel anti-HBV neutralizing antibody or by modulating host
immune responses.
Conclusions: Our study demonstrates that humanized mice with both human immune and liver cells
provide a valuable in vivo platform for studying HBV infection, human immune
responses/immunopathogenesis and associated liver diseases, as well as for developing novel
therapeutics targeting viral and host factors.作者: 战天斗hbv 时间: 2015-3-22 19:47
墨尔本沃尔特与伊莉莎·霍尔研究所(Walter and Eliza Hall Institute)的佩莱格里尼博士(Marc Pellegrini)表示,新药有潜质改革慢性乙肝感染的治疗方式。临床试验将使用一款名叫birinapant的抗癌药物以及一款现存的抗乙肝病毒药物。“这款新药也许能首次治愈乙肝病毒感染。”佩莱格里尼博士说。
Study Rundown: Chronic HBV infection of the liver can cause severe liver disease. While current antiviral drugs such as entecavir prevent viral replication, they do not lead to full elimination of the virus and must be taken indefinitely. The authors of this study showed in a separate report that during chronic infection, cellular inhibitor of apoptosis proteins (cIAPs) in host cells prevented the controlled death of infected hepatocytes and clearance of HBV. This subsequent study investigated the ability of birinapant, a cIAP inhibitor undergoing clinical trial evaluation for cancer treatment, to eliminate HBV during chronic infection.
In a mouse model of chronic HBV infection, birinapant treatment resulted in rapid clearance of detectable HBV genetic material from serum. Moreover, controlled cell death was observed specifically in infected hepatocytes. Combination treatment with birinapant and entecavir led to quicker clearance than treatment with either drug alone. In addition to being effective, the combination therapy did not cause significant toxicity. Overall, this study demonstrated the potential of birinapant to treat chronic HBV infection. In contrast to current antiviral drugs that target HBV itself, birinapant modulated a host cell protein involved in viral persistence. This study showed the advantage of the latter strategy in eliminating rather than merely controlling infection.
Click to read the study in PNAS
Relevant Reading: Birinapant (TL32711), a Bivalent SMAC Mimetic, Targets TRAF2-Associated cIAPs, Abrogates TNF-Induced NF-κB Activation, and Is Active in Patient-Derived Xenograft Models
In-Depth [animal study]: This study evaluated the small molecule cIAP inhibitor birinapant for the treatment of chronic HBV infection. The C57BL/6 mouse model of chronic infection was generated by injecting the animals with plasmid that contained HBV DNA. Drug treatment was initiated one week after plasmid injection.
First, birinapant treatment was evaluated. Over the course of three weeks, animals received a weekly intraperitoneal injection of 30mg/kg birinapant or vehicle control (n=6-7 per group). Five weeks after the initial dose, there were no mice in the birinapant group with detectable serum HBV DNA. In contrast, in the group that received the vehicle control, 15% of mice (one mouse) had detectable serum HBV DNA at 12 weeks after the initial dose. Liver protein level measurements showed that birinapant decreased cIAP levels in both uninfected and infected mice. However, histology of liver tissue showed that controlled cell death promoted by birinapant occurred specifically in infected hepatocytes.
Second, birinapant and entecavir mono- and combination therapies were evaluated. During the one week of drug treatment, 30mg/kg birinapant was administered intraperitoneally at days 0 and 7 and/or 3.2mg/kg entecavir was administered orally daily (n=6 per group). Clearance of HBV DNA was significantly faster in the combination therapy group compared to birinapant alone (p<0.01), entecavir alone (p<0.001), or vehicle control (p<0.001). Specifically, no mice in the combination therapy group had detectable serum HBV DNA at two weeks after initial treatment. Notably, while both birinapant and entecavir monotherapies reduced serum HBV DNA levels below detectable levels, only birinapant also reduced serum HBV surface antigen levels below detectable levels.作者: 战天斗hbv 时间: 2015-4-30 10:18
Although we have had an effective hepatitis B vaccine for a number of years, a cure, or even a specific treatment, has continued to elude scientists. Consequently, in areas where vaccines are not widely available, such as sub-Saharan Africa, as many as 10% of the adult population is chronically infected. But hope could be on the way, as scientists in Australia may have finally found a long sought-after cure.
The promising new treatment, which involves a combination of an antiviral drug and a cancer drug, eliminated the virus in 100% of infected animals tested. And since the drugs are approved and on the market, human safety and efficacy trials are already underway across several cities in Australia. The promising findings have been published in Proceedings of the National Academy of Sciences.
Hepatitis B is a potentially life-threatening infection of the liver caused by the hepatitis B virus (HBV). Normally, healthy adults recover from infection within a year because the presence of the virus triggers a controlled cellular process called apoptosis, which is where cells commit suicide in order to stop the virus persisting and spreading. But unfortunately, the virus is able to interrupt the signals required for this process, and consequently some patients will go on to develop chronic infections that often lead to scarring of the liver or liver cancer, which can be fatal.
Armed with this knowledge, scientists from the Walter and Eliza Hall Institute set out to find a way to interfere with the signaling pathways employed by HBV to prevent cells from destroying themselves. After investigating the behavior of the virus in infected cells, the scientists identified a potential drug candidate: Birinapant.
This drug was actually originally developed as a cancer treatment, but the researchers discovered that it is also capable of flipping HBV’s survival ‘switch,’ thus allowing infected cells to undergo normal apoptosis. Interestingly, the researchers found that they could boost this process by using the drug in conjunction with an existing anti-HBV therapy.
“Birinapant enables the destruction of hepatitis-infected liver cells while leaving normal cells unharmed,” lead researcher Marc Pellegrini said in a statement. “Excitingly, when birinipant was administered in combination with current antiviral drug entecavir, the infection was cleared twice as fast compared with birinapant alone."
When the researchers tested out this combination therapy in infected animals, they were able to cure the virus 100% of the time. This impressive preclinical success led to the initiation of a human trial in December, which will first investigate safety in healthy volunteers and then efficacy in patients with the disease. Hopefully, because the cancer drug does not specifically target bits of the virus, resistance will be difficult to evolve, meaning the treatment should not be quickly rendered ineffective.
Alongside human trials, the researchers would like to continue their work by investigating whether the combination therapy could also be useful in treating other chronic viral diseases, such as herpes or perhaps dengue fever.
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home contact Advertising Privacy Policy Terms of Use 作者: 战天斗hbv 时间: 2015-5-3 20:14
标题是Cancer Drug Cures Mice Of Hepatitis B 作者: newchinabok 时间: 2015-5-3 21:02
战哥是我们的birinapant项目经理作者: 战天斗hbv 时间: 2015-5-3 21:20
This drug was actually originally developed as a cancer treatment, but the researchers discovered that it is also capable of flipping HBV’s survival ‘switch,’ t
我以前就很好奇、一个治疗癌症的药物、到底发生了什么、discover了能治疗hbv、我大胆的猜测、是不是治疗肝癌病人的时候、发现此人的hbv清楚了……理由、肝癌是常见癌症、在肝癌患者中、hbv很常见、所以发生这种事、我认为都不算巧合作者: Olivia123 时间: 2015-5-3 21:58