Wang Yang, Che Yang, Wang ShanShan, Wang JinMing, Liu Xiaoni, Kou Buxin, Guan Yuanyue, Chen Dexi, Shi Ying
Beijing Institute of Hepatology, Beijing YouAn Hospital, Capital Medical University, Beijing, 100069, China.
Beijing Institute of Hepatology, Beijing YouAn Hospital, Capital Medical University, Beijing, 100069, China.
Biochem Biophys Res Commun. 2022 Jun 25;610:61-69. doi: 10.1016/j.bbrc.2022.03.109. Epub 2022 Apr 12.
BACKGROUND & AIM: P53 Apoptosis Stimulating Protein 2 (ASPP2) is confirmed to participate in cellular activities including apoptosis, proliferation, autophagy, injury and so on. However, the role of ASPP2 in Hepatitis B virus (HBV) infection has not been reported in detail. The study explored the role of ASPP2 in HBV induced chronic liver damage.
Transcriptome profiling of ASPP2-konckdown mouse liver were analyzed by RNA-sequencing. HBV-ASPP2-knockdown mice was the hybrid offspring of HBV transgenic mice and ASPP2 knockdown mice. Liver tissues were taken for the experiments such as western Blot (WB), PCR, Hematoxylin and Eosin (HE), Immunohistochemistry and high throughput sequencing of transcriptome.
Pathological and transcriptomic analysis of liver tissue from ASPP2 knockdown vs con mice showed that after ASPP2 knockdown, the pathological changes in the liver tissue of mice were not significant, but transcriptomics showed obvious changes in immune system process, and response to stimulus, metabolism, Human Diseases and other directions etc. In the HBV-ASPP2-knockdown mice, liver tissue HE staining found less cell swelling and necrosis foci; F4/80 and MPO staining showed less inflammatory cell infiltration; serum ALT and AST decreased than the HBV-ASPP2-con mice. Transcriptome results showed significantly changed in HBV-ASPP2-knockdown mice including immune system process, inflammatory response, and innate immune response etc. Further comparison of the two transcriptomes yielded 9 identical pathways related to inflammatory and cell injury. The PPAR pathway was verified, and found that the increase of PPARγ caused by the reduction of ASPP2 is likely to be the reason for the reduction of HBV-related liver injury. The expression of PPARγ was then analyzed by transcriptome and PCR, it was found that in the absence of HBV, ASPP2 knockdown resulted in a mild decrease in PPARγ, and in the presence of HBV infection, ASPP2 knockdown resulted in a marked increase in PPARγ.In addition, this study found that high expression of ASPP2 had opposite effects on HCC (HBV-none) and HCC (HBV-yes).
This study demonstrated that reduction of ASPP2 reduces HBV-induced hepatocyte damage during chronic HBV infection. This phenomenon is related to the different regulation of PPARγ by ASPP2 in the presence or absence of HBV stimulation.
p53凋亡刺激蛋白2（ASPP2）已被证实参与包括凋亡、增殖、自噬、损伤等细胞活动。然而，ASPP2在乙型肝炎病毒（HBV）感染中的作用尚未详细报道。本研究探讨ASPP2在HBV诱导的慢性肝损伤中的作用。
通过RNA测序分析ASPP2基因敲低小鼠肝脏的转录组图谱。HBV-ASPP2基因敲低小鼠是HBV转基因小鼠和ASPP2基因敲低小鼠的杂交后代。取肝脏组织进行蛋白质免疫印迹（WB）、聚合酶链反应（PCR）、苏木精-伊红（HE）染色、免疫组织化学及转录组高通量测序等实验。
ASPP2基因敲低小鼠与对照小鼠肝脏组织的病理和转录组分析表明，ASPP2基因敲低后，小鼠肝脏组织的病理变化不明显，但转录组学显示免疫系统过程、对刺激的反应、代谢、人类疾病等方向有明显变化。在HBV-ASPP2基因敲低小鼠中，肝脏组织HE染色发现细胞肿胀和坏死灶减少；F4/80和髓过氧化物酶（MPO）染色显示炎症细胞浸润减少；血清丙氨酸氨基转移酶（ALT）和天冬氨酸氨基转移酶（AST）水平低于HBV-ASPP2对照小鼠。转录组结果显示，HBV-ASPP2基因敲低小鼠在免疫系统过程、炎症反应和固有免疫反应等方面有显著变化。进一步比较两个转录组，发现9条与炎症和细胞损伤相关的相同通路。对过氧化物酶体增殖物激活受体（PPAR）通路进行验证，发现ASPP2减少导致PPARγ增加可能是HBV相关肝损伤减轻的原因。然后通过转录组和PCR分析PPARγ的表达，发现在无HBV情况下，ASPP2基因敲低导致PPARγ轻度下降，而在HBV感染情况下，ASPP2基因敲低导致PPARγ显著增加。此外，本研究发现ASPP2高表达对肝癌（无HBV）和肝癌（有HBV）有相反的影响。
本研究表明，在慢性HBV感染期间，ASPP2减少可减轻HBV诱导的肝细胞损伤。这种现象与ASPP2在有无HBV刺激下对PPARγ的不同调节有关。
