■针对乙型肝炎病毒(HBV)的新的和更有效的疗法的开发受到缺乏合适的小动物模型的限制。HBV转基因小鼠模型包含一个整合的超长1.3-mer构建体已经产生了重要的见解,但不幸的是,这个模型缺乏共价闭合的环状DNA(cccDNA),附加型HBV转录模板,鉴于HBV整合在每个细胞中,因此无法治愈。
■为了解决这两个问题,我们产生了一个新的转基因小鼠(HBV1.1X),使用Cre/LoxP技术生成可切除的环状HBV基因组。该模型具有敲入ROSA26基因座的HBV1.1-mer盒,设计用于从出生时稳定表达病毒蛋白,像目前的HBV转基因小鼠模型,在基因组切除前引入Cre重组酶。
■我们证明了通过病毒或转基因Cre表达在HBV1.1X小鼠中诱导重组cccDNA(rcccDNA)形成,以及用Cre调节小鼠HBsAg和HBc表达的能力。他莫昔芬诱导的Cre可以显着下调整合HBV基因组的基线HBsAg水平。为了证明HBV从HBV1.1X小鼠的清除,我们施用表达Cre的腺病毒,通过rcccDNA切除和随后的免疫反应,永久且显着降低了鼠肝脏中的HBsAg和核心抗原水平。
■HBV1.1X模型是第一个Cre可调节的HBV转基因小鼠模型,应该是有价值的模仿慢性HBV感染,与新生儿表达和HBV抗原的耐受性,和按需调节HBV表达。
■乙型肝炎病毒(HBV)只能自然感染人类和黑猩猩。小鼠模型已经开发与HBV基因组整合到小鼠染色体,但这会阻止老鼠被治愈。我们开发了一种新的转基因小鼠模型,允许HBV从小鼠染色体切除,形成类似于天然环状HBV基因组的重组环状DNA分子。HBV表达可以在这些小鼠中降低,使治愈疗法能够在这种新的小鼠模型中进行测试。
UNASSIGNED: Development of new and more effective therapies against hepatitis B virus (HBV) is limited by the lack of suitable small animal models. The HBV transgenic mouse model containing an integrated overlength 1.3-mer construct has yielded crucial insights, but this model unfortunately lacks covalently closed circular DNA (cccDNA), the episomal HBV transcriptional template, and cannot be cured given that HBV is integrated in every cell.
UNASSIGNED: To solve these 2 problems, we generated a novel transgenic mouse (HBV1.1X), which generates an excisable circular HBV genome using Cre/LoxP technology. This model possesses a HBV1.1-mer cassette knocked into the ROSA26 locus and is designed for stable expression of viral proteins from birth, like the current HBV transgenic mouse model, before genomic excision with the introduction of Cre recombinase.
UNASSIGNED: We demonstrated induction of recombinant cccDNA (rcccDNA) formation via viral or transgenic Cre expression in HBV1.1X mice, and the ability to regulate HBsAg and HBc expression with Cre in mice. Tamoxifen-inducible Cre could markedly downregulate baseline HBsAg levels from the integrated HBV genome. To demonstrate clearance of HBV from HBV1.1X mice, we administered adenovirus expressing Cre, which permanently and significantly reduced HBsAg and core antigen levels in the murine liver via rcccDNA excision and a subsequent immune response.
UNASSIGNED: The HBV1.1X model is the first Cre-regulatable HBV transgenic mouse model and should be of value to mimic chronic HBV infection, with neonatal expression and tolerance of HBV antigens, and on-demand modulation of HBV expression.
UNASSIGNED: Hepatitis B virus (HBV) can only naturally infect humans and chimpanzees. Mouse models have been developed with the HBV genome integrated into mouse chromosomes, but this prevents mice from being cured. We developed a new transgenic mouse model that allows for HBV to be excised from mouse chromosomes to form a recombinant circular DNA molecule resembling the natural circular HBV genome. HBV expression could be reduced in these mice, enabling curative therapies to be tested in this new mouse model.