筛选新的抗HBV药物及机制研究是国际研究的重点，前期研究中我们发现环庚三烯酚酮羟基化物的衍生物－β-thujaplicinol能作用HBV RNAseH而抑制病毒复制。本项目将利用前期建立的体外biochemical和cell culture药敏体系，从17种该类衍生物中筛选出几种能作用于HBV RNAseH而抑制病毒复制的抑制剂，围绕HBV RNAseH在HBV反转录复制中的作用，通过primer extension analysis等策略逐步弄清楚该类抑制剂在HBV反转录复制环节和cccDNA合成环节中的作用，解析其作用机制，并通过HBV转基因小鼠模型在体内评价该类药物对HBV复制及肝组织学的作用效应，其研究结果不仅阐明了环庚三烯酚酮羟基化物的衍生物中对HBV RNAseH的作用机制，同时通过体外和体内实验评价了该类药物对HBV RNAseH的抑制效应，为该类药物的研发提供了科学依据。

Hepatitis B Virus (HBV) is a hepatotropic DNA virus that replicates by reverse transcription. Therapy primarily employs nucleos(t)ide analogs that suppress viral DNA synthesis by the viral reverse transcriptase very well but rarely cure the infection, therefore, novel drugs against targets other than the reverse transcriptase activity are urgently needed. Reverse transcription requires the viral ribonuclease H (RNAseH) to destroy the viral RNA after it has been copied into DNA. Therefore inhibiting the HBV RNAseH would block both cccDNA replenishment and secretion of new virions. Consequently, RNAseH inhibitors could be used to augment the existing nucleos(t)ide analog drugs to improve suppression of the cccDNA. Previously, we had discovered β-thujaplicinol - a hydroxylated tropolone derivative isolated from the heartwood of Western Red Cedar trees that inhibits the HBV RNAseH with a 50% inhibitory activity of 5.9 ± 0.7 μM, It blocked replication of HBV genotypes A and D in culture by inhibiting the RNAseH activity with an estimated EC50 of 5 μM and a CC50 of 10.1 ± 1.7 μM. In this research, we would investigate the mechanism of hydroxylated tropolone derivative on the HBV RNAseH: first, we would screen the potential HBV RNAseH inhibitors based on a low throughput screening pipeline. then analysis whether these inhibitors would affect HBV reverse transcription such pgRNA encapsidation, the minus strand DNA initiation 、elongation, RNA primer translocation or elongation of plus strand DNA. In addition, we would analysis the inhibition for synthesis of cccDNA which is the key factor of HBV infection. Finally, we would evaluate the efficacy of inhibition by the transgenic mice. This research will reveal how the hydroxylated tropolone derivative affect HBV replication and cccDNA systhesis by blocking the activity of HBV RNAseH, in addition, this would provide essential guidance for developing anti HBV drugs for thses inhibitors.