Nonalcoholic steatohepatitis (NASH) is the most prevalent cause of chronic liver disease in the Western world. However, an optimum therapy for NASH is yet to be established mandating more in-depth investigation into the molecular pathogenesis of NASH to identify novel regulatory molecules and develop targeted therapies. Here, we unravel a unique function of Astrocyte elevated gene-1/Metadherin (AEG-1/MTDH) in NASH using a transgenic mouse with hepatocyte-specific overexpression of AEG-1 (Alb/AEG-1) and a conditional hepatocyte-specific AEG-1 knockout mouse (AEG-1ΔHEP). Alb/AEG-1 mice developed spontaneous NASH while AEG-1ΔHEP mice were protected from high fat diet (HFD)-induced NASH. Intriguingly, AEG-1 overexpression was observed in livers of NASH patients and WT mice that developed steatosis upon feeding high fat diet. In-depth molecular analysis unraveled that inhibition of PPARα activity resulting in decreased fatty acid β-oxidation, augmentation of translation of fatty acid synthase resulting in de novo lipogenesis, and increased NF-κB-mediated inflammation act in concert to mediate AEG-1-induced NASH. Therapeutically, hepatocyte-specific nanoparticle-delivered AEG-1 siRNA provided marked protection from HFD-induced NASH in wild-type mice. Conclusion AEG-1 might be a key molecule regulating initiation and progression of NASH. AEG-1 inhibitory strategies might be developed as a potential therapeutic intervention in NASH patients.

Astrocyte elevated gene-1 (AEG-1) and c-Myc are overexpressed in human hepatocellular carcinoma (HCC) functioning as oncogenes. AEG-1 is transcriptionally regulated by c-Myc and AEG-1 itself induces c-Myc by activating Wnt/β-catenin signaling pathway. We now document cooperation of AEG-1 and c-Myc in promoting hepatocarcinogenesis by analyzing hepatocyte-specific transgenic mice expressing either AEG-1 (Alb/AEG-1), c-Myc (Alb/c-Myc) or both (Alb/AEG-1/c-Myc). WT and Alb/AEG-1 mice did not develop spontaneous HCC. Alb/c-Myc mice developed spontaneous HCC without distant metastasis while Alb/AEG-1/c-Myc mice developed highly aggressive HCC with frank metastasis to the lungs. Induction of carcinogenesis by N-nitrosodiethylamine (DEN) significantly accelerated the kinetics of tumor formation in all groups. However, in Alb/AEG-1/c-Myc the effect was markedly pronounced with lung metastasis. In vitro analysis showed that Alb/AEG-1/c-Myc hepatocytes acquired increased proliferation and transformative potential with sustained activation of pro-survival and epithelialmesenchymal transition (EMT) signaling pathways. RNA-sequencing analysis identified a unique gene signature in livers of Alb/AEG-1/c-Myc mice that was not observed when either AEG-1 or c-Myc was overexpressed. Specifically Alb/AEG-1/c-Myc mice overexpressed maternally imprinted non-coding RNAs, such as Rian, Meg-3 and Migr, which are implicated in hepatocarcinogenesis. Knocking down these ncRNAs significantly inhibited proliferation and invasion by Alb/AEG-1/c-Myc hepatocytes. Conclusion Our studies reveal a novel cooperative oncogenic effect of AEG-1 and c-Myc that might explain the mechanism of aggressive HCC. Alb/AEG-1/c-Myc mice provide a useful model to understand the molecular mechanism of cooperation between these two oncogenes and other molecules involved in hepatocarcinogenesis. This model might also be of use for evaluating novel therapeutic strategies targeting HCC.

Intrauterine adhesions (IUAs) are caused by endometrial damage and are associated with a poor pregnancy prognosis including infertility, oligomenorrhea and recurrent pregnancy loss. Understanding the pathogenesis of IUAs may help prevent and treat this condition more effectively. The aim of the current study was to investigate the function of microRNA-1291 (miR-1291) during the development of IUAs following endometrial damage and elucidate the potential molecular mechanisms involved. The expression of Rho GTPase activating protein 29 (ArhGAP29), a putative target mRNA of miR-1291, was determined by immunohistochemical staining of human endometrial tissue from patients with IUAs and compared with normal endometrial tissues. ArhGAP29 expression was significantly decreased in endometrial tissues with IUAs compared with normal endometrium. Additionally, a murine IUAs model was developed and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) demonstrated that miR-1291 levels were significantly increased in the uterine tissue and plasma of the IUAs group compared with the normal mice. Furthermore, an miR-1291 antagomir was injected into the uterine cavity of experimental IUAs mice to block miR-1291. Hematoxylin and eosin and Masson's stain revealed that blocking miR-1291 significantly ameliorated endometrial fibrosis. Furthermore, levels of epithelial mesenchymal transition (EMT)-associated proteins, and ArhGAP29-RhoA/Rho-associated coiled coil containing protein kinase 1 (ROCK1) were measured in uterine tissue by western blot, RT-qPCR analysis and immunofluorescence staining. Levels of the mesenchymal marker proteins, vimentin and N-cadherin, were increased in the IUAs group mice, accompanied by a relative decrease in the epithelial marker proteins, cytokeratin and E-cadherin compared with normal murine endometrium. miR-1291 inhibition decreased RhoA/ROCK1 expression in the EMT pathway, but increased ArhGAP29 expression. Taken together, the findings indicate that miR-1291 acts upstream of ArhGAP29 to negatively regulate the RhoA/ROCK1 EMT pathway, ultimately leading to endometrial fibrosis. These studies may provide new potential therapeutic options and pave the way to use circulating miR-1291 as a clinical biomarker of endometrial fibrosis.