Growing evidence demonstrates that long noncoding RNAs (lncRNAs) are involved in the progression of various cancers, including hepatocellular carcinoma (HCC). The role of nuclear-enriched abundant transcript 1 (NEAT1), an essential lncRNA for the formation of nuclear body paraspeckles, has not been fully explored in HCC. We aimed to determine the expression, roles and functional mechanisms of NEAT1 in the proliferation and invasion of HCC. Based on real-time polymerase chain reaction data, we suggest that NEAT1 is upregulated in HCC tissues compared with noncancerous liver tissues. The knockdown of NEAT1 altered global gene expression patterns and reduced HCC cell proliferation, invasion and migration. RNA immunoprecipitation and RNA pull-down assays confirmed that U2AF65 binds to NEAT1. Furthermore, the study indicated that NEAT1 regulated hnRNP A2 expression and that this regulation may be associated with the NEAT1–U2AF65 protein complex. Thus, the NEAT1-hnRNP A2 regulation mechanism promotes HCC pathogenesis and may provide a potential target for the prognosis and treatment of HCC.

Background:To establish an animal model of pre-sensitization following liver transplantation either with or without immunosuppressors. To study whether accelerated liver rejection or acute antibody-mediated rejection (AMR) occurred and study the characteristics and potential mechanism in the animal model.Methods: Lewis (LEW) rats were subjected to liver [liver graft of Brown Norway (BN) rat] transplantation 2 weeks after lymphocyte injection (lymphocytes of BN rat; pre-sensitization). At 2 weeks after transplantation, serum samples of recipients were collected for antibody analysis to identify donor-specific alloantibody (DSA) level. The recipients were treated with or without a low dose of immunosuppressor (2 mg/kg). The liver grafts of each group were analyzed by hematoxylin and eosin (HE) stain, Masson stain, CK19, C4d, and CD20 immunohistochemical (IHC) stain, CD3, CD68, and CD86 immunofluorescence and transmission electron microscope (TEM) to study the characteristics of liver rejection. Moreover, cytotoxin-associated genes, M1 macrophages conversion-related proteins, and interleukin-6 (IL-6) signaling pathway proteins were detected by western blotting.Results: High level of DSA and accelerated liver rejection occurred in the pre-sensitized rat models following liver transplant. Accelerated liver graft rejection occurred in the pre-sensitized, post liver transplant rats regardless of whether a low dose immunosuppressor had been applied. Severe injury of the interlobular bile ducts and accelerated fibrosis could be observed. Moreover, evidence of endothelial injury, such as capillary inflammation, was found in the pre-sensitized, post-transplant rats. In addition, C4d deposition and M1 macrophages recruitment were also found in this sensitized followed transplant model, indicating that complement activation might occur in this model. The levels of IL-6, JAK1, STAT3, SHP2, and ERK1-2 were increased in the pre-sensitized, post-transplant rats.Conclusions: Pre-sensitized post liver transplant rats might be potential AMR models for further study.

Background: This study aimed to investigate the roles and functions of nuclear-enriched abundant transcript 1 (NEAT1) in exosome secretion and exosomal microRNA (miRNA) changes in hepatocellular carcinoma (HCC) cells.Methods: HepG2 and HuH-7 cells were divided into two groups: Lv-control (which were infected with lentivirus without NEAT1 expression) and Lv-NEAT1 (which were infected with lentivirus with NEAT1 overexpression). Each group was used to study cell function (proliferation, invasion, and apoptosis) and exosome secretion by nanoparticle tracking analysis (NTA), electron microscopy, and nanoflow cytometry (nanoFCM). Different levels of messenger RNA (mRNA), miRNA, and exosomal miRNA were detected by RNA sequencing. Next, potential target RNAs were verified by reverse transcription polymerase chain reaction (RT-PCR). Changed exosomal miRNAs were found and miRNA mimics were used to study cell function in NEAT1-overexpression and NEAT1-knockdown HCC cells. Results:The data showed that NEAT1-overexpression promoted exosome secretion. The overexpression of NEAT1 altered global genes, including exosome-related genes. Compared with the control group, we observed that several miRNAs changed in the exosomes secreted by NEAT1-overexpressing cells. Our study found that these changed exosomal miRNAs played a suppressor role in HCC. Transfection of miR-634, miR-638, and miR-3960 reversed the enhanced invasion and proliferation in HCC cells with a high level of NEAT1 expression.Conclusions: These results suggested that NEAT1 regulates exosome-related genes, which might be associated with increasing exosome secretion by NEAT1-overexpressing cells. Furthermore, NEAT1 promotes cell invasion and proliferation via downregulation of miR-634, miR-638, and miR-3960 in exosomes. This study may provide potential targets for exosome-mediated miRNA transfer in HCCs with a high level of NEAT1 expression therapy.