Mechanisms of toxicity by proinflammatory cytokines in a novel human pancreatic beta cell line, 1.1B4.

Srividya Vasu, Neville McClenaghan, Janie McCluskey, Peter Flatt

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

BACKGROUND: Molecular mechanisms of toxicity and cell damage were investigated in the novel human beta cell line, 1.1B4, after exposure to proinflammatory cytokines - IL-1β, IFN-γ, TNF-α.METHODS: MTT assay, insulin radioimmunoassay, glucokinase assay, real time reverse transcription PCR, western blotting, nitrite assay, caspase assay and comet assay were used to investigate mechanisms of cytokine toxicity.RESULTS: Viability of 1.1B4 cells decreased after 18h cytokine exposure. Cytokines significantly reduced cellular insulin content and impaired insulin secretion induced by glucose, alanine, KCl, elevated Ca2+, GLP-1 or forskolin. Glucokinase enzyme activity, regulation of intracellular Ca2+ and PDX1 protein expression were significantly reduced by cytokines. mRNA expression of genes involved in secretory function - INS, GCK, PCSK2 and GJA1 was downregulated in cytokine treated 1.1B4 cells. Upregulation of transcription of genes involved in antioxidant defence - SOD2 and GPX1 was observed, suggesting involvement of oxidative stress. Cytokines also upregulated transcriptions of NFKB1 and STAT1, which was accompanied by a significant increase in NOS2 transcription and accumulation of nitrite in culture medium, implicating nitrosative stress. Oxidative and nitrosative stresses induced apoptosis was evident from increased % tail DNA, DNA fragmentation, caspase 3/7 activity, apoptotic cells and lower BCL2 protein expression.CONCLUSIONS: This study delineates molecular mechanisms of cytokine toxicity in 1.1B4 cells, which agree with earlier observations using human islets and rodent beta cells.GENERAL SIGNIFICANCE: This study emphasizes the potential usefulness of this cell line as a human beta cell model for research investigating autoimmune destruction of pancreatic beta cells.
Original languageEnglish
Pages (from-to)136-145
Number of pages10
JournalBIOCHIMICA ET BIOPHYSICA ACTA
Volume1840
Issue number1
Early online date1 Sep 2013
DOIs
Publication statusPublished - 31 Jan 2014

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