1. An siRNA screen identifies transmembrane 7 superfamily member 3 (TM7SF3), a seven transmembrane orphan receptor, as an inhibitor of cytokine-induced death of pancreatic beta cells
- Author
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Benjamin Geiger, Irena Lavelin, Yuval Hart, Tova Volberg, Hadas Shatz-Azoulay, Roi Isaac, Yehiel Zick, and Avital Beck
- Subjects
Male ,Ubiquitin-Protein Ligases ,Endocrinology, Diabetes and Metabolism ,medicine.medical_treatment ,Apoptosis ,Protein Serine-Threonine Kinases ,Biology ,Bioinformatics ,Cell Line ,Proinflammatory cytokine ,Tissue Culture Techniques ,Islets of Langerhans ,Mice ,Insulin-Secreting Cells ,Insulin Secretion ,Internal Medicine ,medicine ,Animals ,Humans ,Insulin ,RNA, Messenger ,RNA, Small Interfering ,Orphan receptor ,Membrane Glycoproteins ,Caspases, Effector ,Transmembrane protein ,Mice, Inbred C57BL ,Membrane glycoproteins ,Cytokine ,Cell culture ,Cancer research ,biology.protein ,Cytokines ,Female ,Signal transduction ,Apoptosis Regulatory Proteins ,Oxidation-Reduction ,Signal Transduction - Abstract
Pro-inflammatory cytokines induce death of pancreatic beta cells, leading to the development of type 1 diabetes. We sought to identify novel players and the underlying mechanisms involved in this process.A high-throughput screen of 3,850 mouse small interfering RNAs (siRNAs) was performed in cytokine-treated MIN6 beta cells. Cells were transfected with the different siRNAs and then treated with a combination of TNFα, IL-1β and IFNγ. Cellular apoptosis (caspase-3/7 activity), and changes in cellular reducing power and cell morphology were monitored. The resulting data were analysed and the corresponding z scores calculated.Several gene families were identified as promoting cytokine-induced beta cell apoptosis, the most prominent being those encoding ubiquitin ligases and serine/threonine kinases. Conversely, deubiquitinating enzymes appeared to reduce apoptosis, while protein phosphatases were mainly associated with lowering cellular reducing power. The screen suggested with high confidence the involvement of several novel genes in cytokine-induced beta cell death, including Camkk2, Epn3, Foxp3 and Tm7sf3, which encodes an orphan seven transmembrane receptor. siRNAs to Tm7sf3 promoted cytokine-induced death of MIN6 cells and human pancreatic islets, and abrogated insulin secretion in these cells. These findings implicate transmembrane 7 superfamily member 3 as a potential new player in the inhibition of cytokine-induced death and in the promotion of insulin secretion from pancreatic beta cells.The signalling pathways and novel genes that we identified in this screen and that mediate beta cell death offer new possible targets for therapeutic intervention in diabetes and its adverse complications.
- Published
- 2011