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Ben-Shoshan SO, Kagan P, Sultan M, Barabash Z, Dor C, Jacob-Hirsch J, Harmelin A, Pappo O, Marcu-Malina V, Ben-Ari Z, Amariglio N, Rechavi G, Goldstein I, Safran M. ADAR1 deletion induces NFκB and interferon signaling dependent liver inflammation and fibrosis. RNA Biol 2016; 14:587-602. [PMID: 27362366 DOI: 10.1080/15476286.2016.1203501] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Adenosine deaminase acting on RNA (ADAR) 1 binds and edits double-stranded (ds) RNA secondary structures found mainly within untranslated regions of many transcripts. In the current research, our aim was to study the role of ADAR1 in liver homeostasis. As previous studies show a conserved immunoregulatory function for ADAR1 in mammalians, we focused on its role in preventing chronic hepatic inflammation and the associated activation of hepatic stellate cells to produce extracellular matrix and promote fibrosis. We show that hepatocytes specific ADAR1 knock out (KO) mice display massive liver damage with multifocal inflammation and fibrogenesis. The bioinformatics analysis of the microarray gene-expression datasets of ADAR1 KO livers reveled a type-I interferons signature and an enrichment for immune response genes compared to control littermate livers. Furthermore, we found that in vitro silencing of ADAR1 expression in HepG2 cells leads to enhanced transcription of NFκB target genes, foremost of the pro-inflammatory cytokines IL6 and IL8. We also discovered immune cell-independent paracrine signaling among ADAR1-depleted HepG2 cells and hepatic stellate cells, leading to the activation of the latter cell type to adopt a profibrogenic phenotype. This paracrine communication dependent mainly on the production and secretion of the cytokine IL6 induced by ADAR1 silencing in hepatocytes. Thus, our findings shed a new light on the vital regulatory role of ADAR1 in hepatic immune homeostasis, chiefly its inhibitory function on the crosstalk between the NFκB and type-I interferons signaling cascades, restraining the development of liver inflammation and fibrosis.
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Affiliation(s)
- Shirley Oren Ben-Shoshan
- a Sheba Cancer Research Center , Chaim Sheba Academic Medical Center, Tel Hashomer , Israel.,d Sackler Faculty of Medicine , Tel Aviv University , Israel
| | - Polina Kagan
- b Liver Research Laboratory , Chaim Sheba Academic Medical Center, Tel Hashomer , Israel.,d Sackler Faculty of Medicine , Tel Aviv University , Israel
| | - Maya Sultan
- b Liver Research Laboratory , Chaim Sheba Academic Medical Center, Tel Hashomer , Israel
| | - Zohar Barabash
- a Sheba Cancer Research Center , Chaim Sheba Academic Medical Center, Tel Hashomer , Israel
| | - Chen Dor
- a Sheba Cancer Research Center , Chaim Sheba Academic Medical Center, Tel Hashomer , Israel
| | - Jasmine Jacob-Hirsch
- a Sheba Cancer Research Center , Chaim Sheba Academic Medical Center, Tel Hashomer , Israel.,e The Mina and Everard Goodman Faculty of Life Sciences , Bar Ilan University , Ramat Gan , Israel
| | - Alon Harmelin
- f Department of Veterinary Resources , Weizmann Institute of Science , Rehovot , Israel
| | - Orit Pappo
- c Department of Pathology , Chaim Sheba Academic Medical Center, Tel Hashomer , Israel
| | - Victoria Marcu-Malina
- a Sheba Cancer Research Center , Chaim Sheba Academic Medical Center, Tel Hashomer , Israel
| | - Ziv Ben-Ari
- b Liver Research Laboratory , Chaim Sheba Academic Medical Center, Tel Hashomer , Israel.,d Sackler Faculty of Medicine , Tel Aviv University , Israel
| | - Ninette Amariglio
- a Sheba Cancer Research Center , Chaim Sheba Academic Medical Center, Tel Hashomer , Israel.,e The Mina and Everard Goodman Faculty of Life Sciences , Bar Ilan University , Ramat Gan , Israel
| | - Gideon Rechavi
- a Sheba Cancer Research Center , Chaim Sheba Academic Medical Center, Tel Hashomer , Israel.,d Sackler Faculty of Medicine , Tel Aviv University , Israel
| | - Itamar Goldstein
- a Sheba Cancer Research Center , Chaim Sheba Academic Medical Center, Tel Hashomer , Israel.,d Sackler Faculty of Medicine , Tel Aviv University , Israel
| | - Michal Safran
- b Liver Research Laboratory , Chaim Sheba Academic Medical Center, Tel Hashomer , Israel
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Ben-Shoshan SO, Simon AJ, Jacob-Hirsch J, Shaklai S, Paz-Yaacov N, Amariglio N, Rechavi G, Trakhtenbrot L. Induction of polyploidy by nuclear fusion mechanism upon decreased expression of the nuclear envelope protein LAP2β in the human osteosarcoma cell line U2OS. Mol Cytogenet 2014; 7:9. [PMID: 24472424 PMCID: PMC3926685 DOI: 10.1186/1755-8166-7-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 01/10/2014] [Indexed: 01/15/2023] Open
Abstract
Background Polyploidy has been recognized for many years as an important hallmark of cancer cells. Polyploid cells can arise through cell fusion, endoreplication and abortive cell cycle. The inner nuclear membrane protein LAP2β plays key roles in nuclear envelope breakdown and reassembly during mitosis, initiation of replication and transcriptional repression. Here we studied the function of LAP2β in the maintenance of cell ploidy state, a role which has not yet been assigned to this protein. Results By knocking down the expression of LAP2β, using both viral and non-viral RNAi approaches in osteosarcoma derived U2OS cells, we detected enlarged nuclear size, nearly doubling of DNA content and chromosomal duplications, as analyzed by fluorescent in situ hybridization and spectral karyotyping methodologies. Spectral karyotyping analyses revealed that near-hexaploid karyotypes of LAP2β knocked down cells consisted of not only seven duplicated chromosomal markers, as could be anticipated by genome duplication mechanism, but also of four single chromosomal markers. Furthermore, spectral karyotyping analysis revealed that both of two near-triploid U2OS sub-clones contained the seven markers that were duplicated in LAP2β knocked down cells, whereas the four single chromosomal markers were detected only in one of them. Gene expression profiling of LAP2β knocked down cells revealed that up to a third of the genes exhibiting significant changes in their expression are involved in cancer progression. Conclusions Our results suggest that nuclear fusion mechanism underlies the polyploidization induction upon LAP2β reduced expression. Our study implies on a novel role of LAP2β in the maintenance of cell ploidy status. LAP2β depleted U2OS cells can serve as a model to investigate polyploidy and aneuploidy formation by nuclear fusion mechanism and its involvement in cancerogenesis.
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Affiliation(s)
- Shirley Oren Ben-Shoshan
- Sheba Cancer Research Center, Chaim Sheba Medical Center, 52621, Tel-Hashomer, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Amos J Simon
- Sheba Cancer Research Center, Chaim Sheba Medical Center, 52621, Tel-Hashomer, Israel.,Institute of Hematology, Chaim Sheba Medical Center, 52621, Tel-Hashomer, Israel
| | - Jasmine Jacob-Hirsch
- Sheba Cancer Research Center, Chaim Sheba Medical Center, 52621, Tel-Hashomer, Israel
| | - Sigal Shaklai
- Sheba Cancer Research Center, Chaim Sheba Medical Center, 52621, Tel-Hashomer, Israel
| | - Nurit Paz-Yaacov
- Sheba Cancer Research Center, Chaim Sheba Medical Center, 52621, Tel-Hashomer, Israel
| | - Ninette Amariglio
- Sheba Cancer Research Center, Chaim Sheba Medical Center, 52621, Tel-Hashomer, Israel.,Institute of Hematology, Chaim Sheba Medical Center, 52621, Tel-Hashomer, Israel
| | - Gideon Rechavi
- Sheba Cancer Research Center, Chaim Sheba Medical Center, 52621, Tel-Hashomer, Israel.,Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Luba Trakhtenbrot
- Sheba Cancer Research Center, Chaim Sheba Medical Center, 52621, Tel-Hashomer, Israel.,Institute of Hematology, Chaim Sheba Medical Center, 52621, Tel-Hashomer, Israel
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