Arachidonic acid actions on functional integrity and attenuation of the negative effects of palmitic acid in a clonal pancreatic β-cell line

Chronic exposure of pancreatic β-cells to saturated non-esterified fatty acids can lead to inhibition of insulin secretion and apoptosis. Several previous studies have demonstrated that saturated fatty acids such as PA (palmitic acid) are detrimental to β-cell function compared with unsaturated fatty acids. In the present study, we describe the effect of the polyunsaturated AA (arachidonic acid) on the function of the clonal pancreatic β-cell line BRIN-BD11 and demonstrate AA-dependent attenuation of PA effects. When added to β-cell incubations at 100 μM, AA can stimulate cell proliferation and chronic (24 h) basal insulin secretion. Microarray analysis and/or real-time PCR indicated significant AA-dependent up-regulation of genes involved in proliferation and fatty acid metabolism [e.g. Angptl (angiopoietin-like protein 4), Ech1 (peroxisomal Δ3,5,Δ2,4-dienoyl-CoA isomerase), Cox-1 (cyclo-oxygenase-1) and Cox-2, P<0.05]. Experiments using specific COX and LOX (lipoxygenase) inhibitors demonstrated the importance of COX-1 activity for acute (20 min) stimulation of insulin secretion, suggesting that AA metabolites may be responsible for the insulinotropic effects. Moreover, concomitant incubation of AA with PA dose-dependently attenuated the detrimental effects of the saturated fatty acid, so reducing apoptosis and decreasing parameters of oxidative stress [ROS (reactive oxygen species) and NO levels] while improving the GSH/GSSG ratio. AA decreased the protein expression of iNOS (inducible NO synthase), the p65 subunit of NF-κB (nuclear factor κB) and the p47 subunit of NADPH oxidase in PA-treated cells. These findings indicate that AA has an important regulatory and protective β-cell action, which may be beneficial to function and survival in the ‘lipotoxic’ environment commonly associated with Type 2 diabetes mellitus.

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Effects of human serum albumin complexed with free fatty acids on cell viability and insulin secretion in the hamster pancreatic β-cell line HIT-T15

Life Sciences ◽

10.1016/j.lfs.2011.02.022 ◽

2011 ◽

Vol 88 (17-18) ◽

pp. 810-818 ◽

Cited By ~ 8

Author(s):

Vivian C. Tuei ◽

Ji-Sook Ha ◽

Chung-Eun Ha

Keyword(s):

Fatty Acids ◽

Insulin Secretion ◽

Human Serum Albumin ◽

Serum Albumin ◽

Cell Viability ◽

Free Fatty Acids ◽

Human Serum ◽

Cell Line ◽

Pancreatic Β Cell ◽

Β Cell

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Effects of pharmacological inhibition of NADPH oxidase or iNOS on pro-inflammatory cytokine, palmitic acid or H2O2-induced mouse islet or clonal pancreatic β-cell dysfunction

Bioscience Reports ◽

10.1042/bsr20090138 ◽

2010 ◽

Vol 30 (6) ◽

pp. 445-453 ◽

Cited By ~ 41

Author(s):

Marta Michalska ◽

Gabriele Wolf ◽

Reinhard Walther ◽

Philip Newsholme

Keyword(s):

Fatty Acids ◽

Insulin Secretion ◽

Nadph Oxidase ◽

Inflammatory Cytokine ◽

Pancreatic Β Cell ◽

Β Cells ◽

Β Cell ◽

Cell Dysfunction ◽

Mouse Islets ◽

Pro Inflammatory Cytokines

Various pancreatic β-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 β-cell insulin secretion, ATP, the NADPH oxidase (nicotinamide adenine dinucleotide phosphate oxidase) component p47phox and iNOS (inducible nitric oxide synthase) levels using primary mouse islets or clonal rat BRIN-BD11 β-cells. Addition of a pro-inflammatory cytokine mixture [IL-1β (interleukin-1β), TNF-α (tumour necrosis factor-α) and IFN-γ (interferon-γ)] 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. H2O2 decreased ATP levels in the cell line, but elevated p47phox 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, H2O2 or fatty acids in islets. While pro-inflammatory cytokines are known to increase p47phox and iNOS levels in β-cells, we now report that H2O2 can increase levels of the latter two proteins, suggesting a key role for positive-feedback redox sensitive regulation of β-cell dysfunction.

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Inhibition ol phosphatidylinositol 3-kinase by wonmannin enhances insulin secretion from the pancreatic β cell line MIN6

The Japanese Journal of Pharmacology ◽

10.1016/s0021-5198(19)46054-x ◽

1995 ◽

Vol 67 ◽

pp. 18

Author(s):

Takasin Sakurai ◽

Shinji Hagiwara ◽

Jun-ichi Miyazaki ◽

Ynshiaki Nonomura

Keyword(s):

Insulin Secretion ◽

Cell Line ◽

Pancreatic Β Cell ◽

Phosphatidylinositol 3 Kinase ◽

Β Cell ◽

Phosphatidylinositol 3

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Investigation of Ultrasound-Mediated Intracellular Ca2+ Oscillations in HIT-T15 Pancreatic β-Cell Line

Cells ◽

10.3390/cells9051129 ◽

2020 ◽

Vol 9 (5) ◽

pp. 1129

Author(s):

Chi Woo Yoon ◽

Nan Sook Lee ◽

Kweon Mo Koo ◽

Sunho Moon ◽

Kyosuk Goo ◽

...

Keyword(s):

Insulin Secretion ◽

Cell Line ◽

Purinergic Signaling ◽

Underlying Mechanism ◽

Resting Cells ◽

Pancreatic Β Cell ◽

Pulsed Ultrasound ◽

Β Cell ◽

Secretion Pathways ◽

Glucose Stimulated Insulin Secretion

In glucose-stimulated insulin secretion (GSIS) of pancreatic β-cells, the rise of free cytosolic Ca2+ concentration through voltage-gated calcium channels (VGCCs) triggers the exocytosis of insulin-containing granules. Recently, mechanically induced insulin secretion pathways were also reported, which utilize free cytosolic Ca2+ ions as a direct regulator of exocytosis. In this study, we aimed to investigate intracellular Ca2+ responses on the HIT-T15 pancreatic β-cell line upon low-intensity pulsed ultrasound (LIPUS) stimulation and found that ultrasound induces two distinct types of intracellular Ca2+ oscillation, fast-irregular and slow-periodic, from otherwise resting cells. Both Ca2+ patterns depend on the purinergic signaling activated by the rise of extracellular ATP or ADP concentration upon ultrasound stimulation, which facilitates the release through mechanosensitive hemichannels on the plasma membrane. Further study demonstrated that two subtypes of purinergic receptors, P2X and P2Y, are working in a competitive manner depending on the level of glucose in the cell media. The findings can serve as an essential groundwork providing an underlying mechanism for the development of a new therapeutic approach for diabetic conditions with further validation.

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