Study Of HPS Knockout Mice Phenotype

Hepatocin（HPS）,also known as Hepatocyte-derived Fibrinogen-Related Protein 1（HFREP-1）or Fibrinogen-Like 1（FGL1）,which is specifically expressed in the liver,is a liver-specific growth factor.Previous laboratory results showed that HNF-1α（Hepatocyte nuclear factor 1α）regulates HPS specifically expressed in the liver and is up-regulated during liver regeneration;HPS stimulates proliferation of normal hepatocytes by autocrine by activating MAPK and ERK signaling pathways.Exogenous HPS can effectively resist liver injury induced by carbon tetrachloride（CCl₄）;knocking down HPS in zebrafish inhibits hepatocyte proliferation,resulting in delayed liver growth.In this research project,HPS knockout mouse models were established using CRISPR/Cas9 technology,and the phenotypes of HPS knockout mice were studied systematically.HPS knockout mice were able to reproduce normally and no significant abnormality was observed overall.Detection of mouse body weight,liver index,blood biochemistry,basal metabolism,liver tissue structure found:HPS knockout mice were significantly heavier than wild-type mice,their liver weight was small,white adipose cells and brown Adipose tissue cells became significantly larger and no significant changes were found in other major organs.Blood biochemical analysis showed that serum ALT and AST levels were slightly elevated in HPS knockout mice,suggesting that HPS gene knockout may cause liver damage in mice.We used RNA-Seq to detect changes in gene expression profiles in the liver of HPS knockout mice.Compared with HPS^+/+mice,HPS knockout mice up-regulated 202genes in the liver and down-regulated 70 genes.The analysis of differentially expressed GO showed that the up-regulated genes were mainly enriched in endoplasmic reticulum stress and unfolded protein response pathways,and the down-regulated genes were mainly enriched in substance metabolism,liver development,and transcriptional regulatory pathways.This suggests that endoplasmic reticulum stress may be the cause of minor liver damage in HPS knockout mice.In order to detect the proliferation of hepatocytes after HPS knockout,we used a70%hepatectomy mouse model to observe the liver regeneration ability of HPS knockout mice after hepatectomy,and to detect BrdU incorporation rate and PCNA and P-HDAC3.The protein expression of HPS knockout mice was found to be weaker in liver regeneration than wild type mice.Further,we used immunohistochemical techniques to detect the expression of proliferating cell nuclear antigen（PCNA）and cell proliferation marker protein（Ki67）.The results are basically consistent with the results of BrdU labeling,suggesting that knockout of HPS knocks down the mice after 70%of liver resection The ability of liver regeneration.In order to confirm the role of HPS in liver injury,we studied the reactivity of HPS knockout mice to CCl₄-induced injury.Mice were injected intraperitoneally with 1%CCl₄（soluble in soybean oil）and sampled 24 hours after injection.H&E The staining results showed that compared with wild-type mice,HPS knockout mice showed large areas of hepatocyte necrosis.This result shows that HPS knockout will aggravate the damage of mouse hepatocytes,verifying that HPS is resistant to liver injury.Important role.In vitro experiments showed that the primary hepatocytes of HPS knockout mice released ALT and lactate dehydrogenase（LDH）levels after CCl₄ stimulation was significantly higher than that of wild mouse liver cells,supporting the conclusion that HPS plays an important role in anti-hepatic injury.In summary,this study systematically analyzed the phenotype of HPS knockout mouse models and found that HPS knockout resulted in slow liver growth,reduced liver regeneration,and increased CCl₄-induced liver injury,suggesting HPS in the liver It plays an important role in cell proliferation and anti-injury,providing experimental basis for the treatment of severe liver disease with recombinant HPS.