Project description:To elucidate the function of Airn isoforms in the heart, we conducted loss-of-function experiments in murine cardiomoycyte cell line HL-1.
Project description:To elucidate the function of Airn isoforms in the heart, we conducted RNA immunoprecipitation experiment followed by microarray (RIP-chip) in murine cardiomoycyte cell line HL-1.
Project description:To test if the imprinted long non-coding RNA (lncRNA) Airn transcription or its product silences the protein-coding Igf2r gene, we shortened the endogenous lncRNA to four different lengths by inserting polyadenylation (polyA) cassettes on the paternal chromosome via homologous recombination in ES cells. ES cell differentiation was used to recapitulate the developmental onset of Airn and Igf2r imprinted expression and polyA cassettes inserted before (T3, T16, T27) or after (T31, T51) the Igf2r promoter successfully truncated Airn, with the exception of T27. RNA hybridization to a tiling array (MIRTA) demonstrated loss of Airn upstream of the Igf2r promoter (except T27) and absence of novel spliced variants in all truncation alleles. To further test the transcriptional overlap model we moved the Airn promoter ~700bp before the Igf2r TSS in ES cells that lack an endogenous paternal Airn promoter and called this cell line FAP (Forward-Airn-Promoter). RNA hybridization to a tiling array (MIRTA) demonstrated that the moved Airn promoter expresses Airn in wildtype orientation and terminates at the wildtype 3' end. ES cell lines expressing different Airn variants were differentiated on gelatinized dishes after feeder cell depletion and LIF withdrawal by 0.27M-BM-5M retinoic acid for 5 days and Airn length was assayed.
Project description:Long noncoding RNAs (lncRNAs) have emerged as important regulators in a variety of human diseases. It has been suggested that dysregulation of liver sinusoidal endothelial cells (LSECs) phenotype is a critical early event in the fibrotic process. However, the biological function of lncRNAs in LSECs still remains unclear. Here, we identified that lncRNA-Airn was significantly up-regulated in liver tissues and LSECs of CCl4-induced liver fibrosis. Moreover, the expression of AIRN in human cirrhotic liver tissues and serums was remarkably increased as compared with healthy controls. In vivo studies showed that Airn deficiency aggravated CCl4- and BDL-induced liver fibrosis, while Airn overexpression by adeno-associated viral vector serotype 8 vector alleviated CCl4-induced liver fibrosis. Furthermore, we revealed that Airn maintained LSECs differentiation in vivo and in vitro. Additionally, Airn inhibited hepatic stellate cells (HSCs) activation indirectly by regulating LSECs differentiation and promoted hepatocytes (HCs) proliferation by the increased paracrine secretion of Wnt2a and HGF from LSECs. Mechanistically, our results demonstrated that Airn maintained LSECs differentiation through KLF2-endothelial nitric oxide synthase (eNOS)-soluble guanylate cyclase (sGC) pathway, thereby promoting HSCs quiescence and HCs proliferation. In conclusion, our work identified that Airn is beneficial to liver fibrosis by maintaining LSECs differentiation and might be a novel serum biomarker for liver fibrogenesis.
Project description:To test if the imprinted long non-coding RNA (lncRNA) Airn transcription or its product silences the protein-coding Igf2r gene, we shortened the endogenous lncRNA to four different lengths by inserting polyadenylation (polyA) cassettes on the paternal chromosome via homologous recombination in ES cells. ES cell differentiation was used to recapitulate the developmental onset of Airn and Igf2r imprinted expression and polyA cassettes inserted before (T3, T16, T27) or after (T31, T51) the Igf2r promoter successfully truncated Airn, with the exception of T27. RNA hybridization to a tiling array (MIRTA) demonstrated loss of Airn upstream of the Igf2r promoter (except T27) and absence of novel spliced variants in all truncation alleles. To further test the transcriptional overlap model we moved the Airn promoter ~700bp before the Igf2r TSS in ES cells that lack an endogenous paternal Airn promoter and called this cell line FAP (Forward-Airn-Promoter). RNA hybridization to a tiling array (MIRTA) demonstrated that the moved Airn promoter expresses Airn in wildtype orientation and terminates at the wildtype 3' end.
Project description:The mechanisms and biological roles of Polycomb repressive complex (PRC) recruitment by lncRNAs remain unclear. To gain insight, we expressed two lncRNAs that recruit PRCs to multi-megabase domains, Airn and Xist, from an ectopic locus and compared effects. Unexpectedly, ectopic Airn recruited PRC1 and PRC2 to chromatin with a potency resembling Xist yet did not repress genes. Compared to PRC2, PRC1 was more proximal to Airn and Xist, where its enrichment over C-rich elements required the RNA-binding protein HNRNPK. Fusing Airn to Repeat A, the domain required for gene silencing by Xist, enabled gene silencing and altered local patterns but not relative levels of PRC-directed modifications. Our data suggest that endogenously, Airn recruits PRCs to maintain rather than initiate gene silencing; that PRC recruitment occurs independently of Xist Repeat A; and that protein-bridged interactions, not direct RNA contacts, underlie PRC recruitment by Airn, Xist, and other lncRNAs.