Effects of pharmacological inhibition of NADPH oxidase or iNOS on pro-inflammatory cytokine, palmitic acid or H2O2-induced mouse islet or clonal pancreatic ß-cell dysfunction
MetadataShow full item record
Various pancreatic ß-cell stressors including cytokines and saturated fatty acids are known to induce oxidative stress, which results in metabolic disturbances and a reduction in insulin secretion. However, the key mechanisms underlying dysfunction are unknown. We investigated the effects of prolonged exposure (24 h) to pro-inflammatory cytokines, H2O2 or PA (palmitic acid) on ß-cell insulin secretion, ATP the NADPH oxidase (nicotinamide adenine dinucleotide phosphate oxidase) component p47 phox and iNOS (inducible nitric oxide synthase) levels using primary mouse islets or clonal rat BRIN-BD11 ß-cells. Addition of a pro-inflammatory cytokine mixture [IL-1ß (interleukin-1ß), TNF-a (tumour necrosis factor-a) and IFN-? (interferon-?)] or H2O2 (at sub-lethal concentrations) inhibited chronic (24 h) levels of insulin release by at least 50% (from islets and BRIN-BD11 cells), while addition of the saturated fatty acid palmitate inhibited acute (20 min) stimulated levels of insulin release from mouse islets. H2O 2 decreased ATP levels in the cell line, but elevated p47 phox and iNOS levels as did cytokine addition. Similar effects were observed in mouse islets with respect to elevation of p47phox and iNOS levels. Addition of antioxidants SOD (superoxide dismutase), Cat (catalase) and NAC (N-acetylcysteine) attenuated H2O2 or the saturated fatty acid palmitate-dependent effects, but not cytokine-induced dysfunction. However, specific chemical inhibitors of NADPH oxidase and/or iNOS appear to significantly attenuate the effects of cytokines, H2O 2 or fatty acids in islets. While pro-inflammatory cytokines are known to increase p47phox and iNOS levels in ß-ceils, we now report that H2O2 can increase levels of the latter two proteins, suggesting a key role for positive-feedback redox sensitive regulation of ß-cell dysfunction. ©The Authors Journal compilation ©2010 Biochemical Society.
Showing items related by title, author, creator and subject.
Pigment epithelium-derived factor (PEDF) regulates metabolism and insulin secretion from a clonal rat pancreatic beta cell line BRIN-BD11 and mouse isletsChen, Y.; Carlessi, Rodrigo; Walz, N.; Cruzat, Vinicius; Keane, Kevin; John, A.; Jiang, F.; Carnagarin, R.; Dass, C.; Newsholme, Philip (2016)Pigment epithelium-derived factor (PEDF) is a multifunctional glycoprotein, associated with lipid catabolism and insulin resistance. In the present study, PEDF increased chronic and acute insulin secretion in a clonal rat ...
Pallebage-Gamarallage, Menuka Madhavi Somapala (2012)Alzheimer’s disease (AD) is the most common cause of dementia pathologically characterised by neurovascular inflammation, extracellular proteinaceous deposits enriched in amyloid-β (Aβ) and formation of neurofibrillar ...
Elevated levels of branched-chain amino acids have little effect on pancreatic islet cells, but L-arginine impairs function through activation of the endoplasmic reticulum stress responseMullooly, N.; Vernon, W.; Smith, D.; Newsholme, Philip (2014)New Findings - What is the central question of this study?: Recent studies have demonstrated strong correlations between circulating branched-chain amino acid (AA) levels and insulin resistance, a predictor of susceptibility ...