| Part ? Role of IncRNA-MALAT1 in the regulation of hepatocyte proliferation during liver regenerationAim The purpose of our study is to investigate the biological role and mechanisms of IncRNA-MALAT1 in liver regeneration.Methods The expression levels of MALAT1 in liver tissues during liver regeneration in mice after 2/3 partial hepatectomy (PH) at various time-points or cell lines were detected by RT-qPCR. The apoptosis of hepatocytes in liver regeneration after 2/3 hepatectomy was detected by TUNEL immunohistochemical. Gene gain-loss assays was used to silence or overexpression MALAT1, CCK8 and Edu assay were used to detect the differences in the activity of hepatocyte lines, and flow cytometry analisis detect the cell cycle and apoptosis of hepatocyte lines. The expression changes of P-catenin destruction complex (Axinl, APC and GSK-3?), and downstream target genes(CyclinDl and C-MYC) after silence or overexpression MALATlwere detected by RT-qPCR and Western blotting. The changes of the expression of ?-catenin after silence MALAT1 was detected by immunofluorescence.Results We found MALAT1 was up-regulated during liver regeneration, and MALAT1 enhanced hepatocyte proliferation by promoting progression of the cell cycle and reduce apoptosis in vitro. Furthermore, we showed that MALAT1 was regulated by p53 during liver regeneration, and p53 maybe a key upstream mediator of MALAT1 activity. Mechanistically, we discovered that MALAT1 facilitated cyclin Dl expression through activation of Wnt/?-catenin signaling by way of suppression of Axin1 and APC.Conclusions MALAT1 promotes cell cycle progression and accelerates hepatocyte proliferation during liver regeneration by activating Wnt/?-catenin signaling. Pharmacological intervention targeting MALAT1 may be therapeutically beneficial in liver failure and liver transplantation by inducing liver regeneration.Part ? p53 and p21 dynamic regulation of liver regeneration after 2/3 partial hepatectomy in miceObjective To investigate the dynamic changes of p53 and p21 in the liver regeneration after 2/3 partial hepatectomy (PH) in mice and the regulation significance.Methods Mouses were operated 2/3 partial hepatectomy, then blood and liver tissue samples were collected at different time points after operation. The expression of serum alanine transaminase(ALT), aspartate aminotransferase(AST) and albumin (ALB) in different time points after hepatectomy was detected by enzyme linked immunosorbent assay (ELISA). The changes of p53, p21 mRNA and protein expression in mouse liver tissues at different time points after hepatectomy were detected by quantitative PCR, immunohistochemistry, and Westtern Blotting. Hepatocytes apoptosis were detected by Tunel immunohistochemical.Results All the mouses in each group had been successfully completed the operations. The ALT, AST and ALB in postoperative 24h,36h were higher comparing with Oh, the difference was statistically significant (P<0.01); the difference of ALT between 72h and Oh, AST between 48h and Oh were statistically significant (P<0.05). Compared with Oh, the proliferating cell nuclear antigen(PCNA) index was (10.28±1.08)%(P<0.01); PCNA index reaching the peak at 36h was(44.19±2.83)% (P<0.01). Compared with Oh, the expression of p53 mRNA was the lowest in 15h after hepatectomy (2-??CT=0.17±0.02, P<0.01), and the highest in 120h (2-??CT=1.68±0.36, P<0.05). After hepatectomy, the expression of p21 mRNA appeared two peak respectively in 36 h (2-??CT=3.49±0.24, P<0.01) and 120h (2-??CT=3.52±0.23, P<0.01). The levels of p53 and p21 protein were consistent with the change of the mRNA. At 120h after hepatectomy, in vascular endothelial cells, the positive rate of immunohistochemistry of p53 and p21 protein was as high as (98.29±1.57)% and (98.72±1.21)%.Conclusion p53 and p21 dynamic regulation of liver regeneration after 2/3 partial hepatectomy in mice. P53, p21 is expected to become prognosis assessment indicators of a variety of liver diseases and liver resection. |
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