The Role Of Histone Acetyltransferase MOF In Mouse Liver Regeneration

The liver is an important metabolic organ and detoxification site of the body.It is the key organ to maintain the metabolic stability of the body which is responsible for the metabolism,synthesis,storage and redistribution of nutrients.Mature hepatocytes do not undergo cell division under normal conditions,but after liver damage or infection,they will rapidly regain proliferation ability.The process of liver regeneration resulting from Partial Hepatectomy(PH)is essentially self-replicating by mature hepatocytes.After liver resection,the structure of the remaining liver will change significantly.The process of liver regeneration mainly consists of three stages:initiation,proliferation and termination.After partial hepatectomy,a series of cytokines secreted by liver cells interact with cytokines secreted by other organs,activate the growth factor and metabolic pathway of hepatocytes,and initiate the proliferation of hepatocytes.When liver regeneration has restored the liver to normal liver weight before surgery,the inhibiting factors of liver regeneration can stop at the end of liver regeneration and prevent cell proliferation from out of control.Histone modification is a modality of epigenetic regulation.In eukaryotic cells,acetylation is the predominant form of covalent modification of core histones.Acetylation modification is a synergistic interaction between histone acetyltransferase(HATs)and histone deacetylase(HDACs),which makes histone acetylation level in a dynamic balance,thereby regulating gene expression.MOF,a histone acetyltransferase in the MYST family,acetylates the 16th lysine(H4K16)of histone H4.MOF plays an important role in the process of cell proliferation in mammalian embryogenesis and tumorigenesis,and plays an essential role in DNA damage repair.MOF plays an irreplaceable role in normal cell proliferation,differentiation,embryo development,DNA damage repair and tumor development,because of acetylation can activate gene transcription.Objective:By establishing a partial liver resection model of mice,the role of acetyltransferase MOF in liver regeneration was explored,and the regulation mechanism of MOF in liver regeneration was preliminarily explored,and the epigenetic regulation in liver regeneration was discussed.Research methods:1.Complete protein was extracted from the liver lobe of mice,and Western Blot was used to detect the protein levels of MOF in the normal state of wild type mice and after partial liver resection.2.A partial hepatectomy model was established in mice.After intraperitoneal injection of chloral hydrate in mice,the abdomen was dissected to expose the abdominal cavity,and the left outer lobe and the middle lobe of liver were excised by silk ligation.3.MOF gene expression deletion mouse model was established.MOFflox/flox genotype mice were mated with Alb-cre genotype mice,and two generations later,MOFfl/fl Alb-cre genotype mice with missing expression of liver MOF were obtained.4.After 70%liver resection in mice,the liver and body weight of mice were weighed at several points after surgery.The ratio of liver and body weight was calculated,and the change trend of liver weight in postoperative mice was detected to study the liver regeneration.5.Serum of mice was taken for detection of liver function indicators ALT and AST at 48h after 70%liver resection.6.The liver tissue of mice was extracted and embedded in paraffin.HE staining was used to verify the structural changes of the liver.7.The paraffin sections of liver tissue after liver resection were stained with Ki67 immunofluorescence to verify the proliferation status of hepatocytes;8.The regulation mechanism of MOF in liver regeneration was preliminarily discussed by real-time quantitative PCR at the transcriptional level.Results:1.Protein expression level of MOF in different liver lobe tissues of mice:Western Blot results showed that MOF expression was higher in the left lateral lobe(LLL)and middle lobe(ML)of the liver of wild-type mice,and lower in the right lobe(RL)and tail lobe(CL).Through the successful model of 30%partial liver resection in mice,it was found that the expression of MOF gradually increased with the regeneration process after 30%partial liver resection.2.Through the successful establishment of 70%partial liver resection model of mice,it was found that the liver tissue of mice can regenerate after surgery and recover the liver weight before surgery.The liver function indexes ALT and AST were significantly increased at 48h after operation,and the results of HE staining showed significant hepatic steatosis in liver tissues.The number of positive cells in Ki67 staining significantly increased,suggesting that liver cells have a significant ability to grow and proliferate.3.Through the successful establishment of the MOF knockout mouse model,it was found that the ALT level of the MOF mice was significantly reduced after the liver resection of 70%,and the changes of AST were not obvious.According to the relative liver weight index,the liver regeneration rate was significantly increased in the early postoperative period(within 6 days)compared with the control group,and the HE staining results showed that liver tissue showed a relatively light degree of hepatic steatosis in mice with normal MOF expression.4.Western Blot results showed that MOF protein expression gradually increased in the early stage of liver regeneration,suggesting that MOF plays a role in the early stage of liver regeneration.The results of real-time quantitative PCR indicated that the absence of MOF resulted in the increased mRNA level of SIRT1 and the decreased mRNA level of TGF?1.Conclusions:The expression of MOF in mouse liver was different.After partial liver resection in mice,MOF is involved in the regulation of liver regeneration and plays a role in the early stage of liver regeneration.The loss of MOF can reduce the liver injury after liver resection and reduce the changes of liver morphology and structure,and promote the liver regeneration process.The results also revealed that MOF may affect the liver regeneration process after liver resection by regulating the expression of TGF 1 and SIRT1.