OBJECTIVE: To investigate the role of Fpr2 in liver homeostasis and host resistance to bacterial infections.
METHODS: Transcriptome sequencing was performed on the livers of Fpr2-/- and wild-type (WT) mice. Differentially expressed genes (DEGs) were identified in the Fpr2-/- and WT mice, and the biological functions of DEGs were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) en-richment analysis. Quantitative real time-polymerase chain reaction (qRT-PCR) and western blot (WB) analyses were used to further validate the expression levels of differential genes. Cell counting kit-8 assay was employed to investigate cell survival. The cell cycle detection kit was used to measure the distribution of cell cycles. The Luminex assay was used to analyze cytokine levels in the liver. The serum biochemical indices and the number of neutrophils in the liver were measured, and hepatic histopathological analysis was performed.
RESULTS: Compared with the WT group, 445 DEGs, including 325 upregulated genes and 120 downregulated genes, were identified in the liver of Fpr2-/- mice. The enrichment analysis using GO and KEGG showed that these DEGs were mainly related to cell cycle. The qRT-PCR analysis confirmed that several key genes (CycA, CycB1, Cdc20, Cdc25c, and Cdk1) involved in the cell cycle had significant changes. The WB analysis confirmed a decrease in the expression of CDK1 protein. WRW4 (an antagonist of Fpr2) could inhibit the proliferation of HepG2 cells in a concentration dependent manner, with an increase in the number of cells in the G0/G1 phase, and a decrease in the number of cells in the S phase. Serum alanine aminotransferase levels increased in Fpr2-/- mice. The Luminex assay measurements showed that interleukin (IL)-10 and chemokine (C-X-C motif) ligand (CXCL)-1 levels were significantly reduced in the liver of Fpr2-/- mice. There was no difference in the number of neutrophils, serum C-reactive protein levels, and liver pathology between WT and Fpr2-/- mice.
CONCLUSIONS: Fpr2 participates in the regulation of cell cycle and cell proliferation, and affects the expression of IL-10 and CXCL-1, thus playing an important protective role in maintaining liver homeostasis.
目的:探讨Fpr2在肝脏稳态和宿主对细菌感染的耐药性中的作用。
方法:对Fpr2-/-和野生型(WT)小鼠的肝脏进行转录组测序。在Fpr2-/-和WT小鼠中鉴定了差异表达基因(DEGs),并通过基因本体论(GO)和京都基因和基因组百科全书(KEGG)富集分析分析了DEGs的生物学功能。定量实时聚合酶链反应(qRT-PCR)和蛋白质印迹(WB)分析用于进一步验证差异基因的表达水平。采用细胞计数试剂盒-8测定来研究细胞存活。细胞周期检测试剂盒用于测量细胞周期的分布。Luminex测定用于分析肝脏中的细胞因子水平。测定血清生化指标和肝脏中性粒细胞数量,并进行肝组织病理学分析。
结果:与WT组相比,445DEG,包括325个上调基因和120个下调基因,在Fpr2-/-小鼠的肝脏中鉴定。使用GO和KEGG的富集分析表明,这些DEGs主要与细胞周期有关。qRT-PCR分析证实了几个关键基因(CycA,CycB1,Cdc20,Cdc25c,而Cdk1)参与的细胞周期发生了显著的变化。WB分析证实了CDK1蛋白表达的降低。WRW4(Fpr2的拮抗剂)能够以浓度依赖的方式抑制HepG2细胞的增殖,随着G0/G1期细胞数量的增加,S期细胞数减少。Fpr2-/-小鼠血清丙氨酸转氨酶水平升高。Luminex分析测量显示,在Fpr2-/-小鼠的肝脏中,白细胞介素(IL)-10和趋化因子(C-X-C基序)配体(CXCL)-1水平显著降低。中性粒细胞的数量没有差异,血清C反应蛋白水平,和WT和Fpr2-/-小鼠之间的肝脏病理学。
结论:Fpr2参与细胞周期和细胞增殖的调节,并影响IL-10和CXCL-1的表达,从而对维持肝脏稳态发挥重要的保护作用。