Different role of saturated and unsaturated fatty acids in β-cell apoptosis

Eitel, Katrin; Staiger, Harald; Brendel, Mathias D.; Brandhorst, Daniel; Bretzel, Reinhard G.; Häring, Hans‐Ulrich; Kellerer, Monika

doi:10.1016/s0006-291x(02)02752-3

Cited by 119 publications

(114 citation statements)

References 13 publications

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“…Although the presence of unsaturated fatty acids alone did not enhance IL-6 mRNA levels, coincubation of myotubes with equimolar concentrations of linoleate and palmitate completely prevented the stimulatory action of the saturated FFAs. A protective effect of unsaturated FFAs on palmitate-mediated lipotoxicity has also been described recently for pancreatic ␤-cell apoptosis (43,44). In this report, it could be demonstrated that excess palmitate is poorly incorporated into triglyceride and causes apoptosis (43).…”

Section: Discussionsupporting

confidence: 67%

Palmitate, but Not Unsaturated Fatty Acids, Induces the Expression of Interleukin-6 in Human Myotubes through Proteasome-dependent Activation of Nuclear Factor-κB

Weigert

Brodbeck

Staiger

et al. 2004

Journal of Biological Chemistry

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243

189

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Circulating interleukin-6 (IL-6), insulin, and free fatty acid (FFA) concentrations are associated with impaired insulin action in obese and type 2 diabetic individuals. However, a causal relationship between elevated plasma FFAs and IL-6 has not been shown. Because skeletal muscle represents a major target of impaired insulin action, we studied whether FFAs may affect IL-6 expression in human myotubes. We demonstrate that specifically saturated FFAs, e.g. palmitate (0.25 mM), induce IL-6 mRNA expression and protein secretion by a proteasome-dependent mechanism that leads to a rapid and chronic activation of nuclear factor-B. Insulin, high glucose concentrations, or unsaturated FFAs did not activate IL-6 expression. In fact, the unsaturated FFA linoleate inhibited palmitate-induced IL-6 production. Because inhibition of palmitate metabolism by the acyl-CoA synthetase inhibitor triacsin C did not abolish IL-6 expression, it appears that the palmitate molecule per se exerts the observed effects. Furthermore, we show that in human myotubes, IL-6 activates the phosphorylation of signal transducer and activator of transcription 3 in concentrations similar to hepatocytes. However, no inhibitory effect of IL-6 on insulin action, determined as phosphatidylinositol 3-kinase association with insulin receptor substrate-1, Akt phosphorylation, and glycogen synthesis, was detected. We conclude that IL-6 expression may be modulated by the composition of circulating FFA, e.g. by diet, and that skeletal muscle cells could be target cells for IL-6.

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Section: Discussionsupporting

confidence: 67%

Palmitate, but Not Unsaturated Fatty Acids, Induces the Expression of Interleukin-6 in Human Myotubes through Proteasome-dependent Activation of Nuclear Factor-κB

Weigert

Brodbeck

Staiger

et al. 2004

Journal of Biological Chemistry

Self Cite

243

189

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“…41) MUFAs are generally less toxic than saturated fatty acids, and it was reported that MUFAs protected saturated fatty acids-induced apoptosis in cells. 42) Unbalanced accumulation of saturated fatty acids were reported in livers of mice fed with MCD diets concerned with decrease of SCD-1, suggesting that depletion of MUFAs contribute to liver injury. 42) Li et al reported that feeding of MCD diets to SCD-1 deficient mice increased hepatocellular apoptosis, liver injury and fibrosis although hepatic steatosis was ameliorated.…”

Section: -23)mentioning

confidence: 99%

A Novel Inhibitor of Stearoyl-CoA Desaturase-1 Attenuates Hepatic Lipid Accumulation, Liver Injury and Inflammation in Model of Nonalcoholic Steatohepatitis

Kurikawa

Takagi

Wakimoto

et al. 2013

Biological & Pharmaceutical Bulletin

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Stearoyl-CoA desaturase-1 (SCD-1) catalyzes the biosynthesis of monounsaturated fatty acids, and their abnormality is possibly responsible for obesity, insulin resistance, hepatic steatosis and nonalcoholic steatohepatitis (NASH). A novel SCD-1 inhibitor, N-(2-hydroxy-2-phenylethyl)-6-[4-(2-methyl benzoyl) piperi din-1-yl]pyridazine-3-carboxamide, has been obtained. The compound inhibited liver SCD-1 activity and increased liver triglyceride accumulation in mice fed with non-fat, high-sucrose diets. In order to evaluate the effects of the SCD-1 inhibitor on NASH development, rats were fed with lipogenic methionine and choline-deficient (MCD) diets for 8 weeks. The SCD-1 inhibitor was administered once-daily at a dose of 30 or 100 mg/kg/d by oral gavage. Administration of a high dose of the SCD-1 inhibitor decreased triglyceride accumulation in the liver of NASH rats by 80%. Administration of a high dose of the SCD-1 inhibitor attenuated the increase of aspartate aminotransferase (AST) and alanine transaminase (ALT) by 86% and 78%, respectively. Hepatic steatosis, hepatocellular degeneration and inflammatory cell infiltration were histologically observed in the liver of NASH rats, and administration of the SCD-1 inhibitor ameliorated these crucial observations in NASH. In summary, an SCD-1 inhibitor ameliorated hepatic triglyceride accumulation, liver injury, hepatocellular degeneration and inflammation in experimental NASH models. These results suggest that SCD-1 maybe a promising target for the treatment of NASH.Key words stearoyl-CoA desaturase-1; steatohepatitis; methionine choline-deficient diet Nonalcoholic fatty liver disease (NAFLD), which is identified with excess lipid accumulation in the liver, is strongly associated with obesity, insulin resistance, hypertension, dyslipidemia and metabolic syndrome.1,2) Most NAFLD are in prognosis, although some of these progress to nonalcoholic steatohepatitis (NASH), which is defined as a histological observation of hepatocellular degeneration, inflammation and fibrosis in liver with steatosis. Finally, some NASH patients progress to liver cirrhosis and hepatocellular carcinomas, which are at the end-stage of liver disease. It is postulated that 3 to 6% of the population indicates NASH in the United States, and it is expected that the population of NASH patients will increase in the future.2) Therefore, there is a pressing need for developing a therapeutic drug to treat NASH. There are however, no therapeutic drugs approved for treating NASH patients, although some clinical pilot studies have indicated that some compounds, including insulin sensitizers, anti-dyslipidemic drugs, anti-hypertensive drugs, anti-obesity drugs and antioxidants, were effective for NASH/NAFLD. 3-9)Stearoyl-CoA desaturase (SCD) is an endoplasmic reticulum enzyme that catalyzes the biosynthesis of monounsaturated fatty acids (MUFAs) from saturated fatty acyl-CoAs. 10)SCD in conjunction with the reduced nicotinamide adenine dinucleotide phosphate (NADPH), the flavoprotein cytochrome b5 reducta...

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“…Palmitate is the most prevalent saturated fatty acid in circulation, and its level is further elevated in patients with NASH (37). The lipotoxic effect has been observed in pancreatic b-cells (47,93), cardiomyocytes (77,101), and hepatic cell lines (50,72,84,128,140,154). Molina et al, recently described a role for mitochondrial dynamics in the progression of the lipotoxic effect, or lipidinduced apoptosis, of FFA incubation in pancreatic b-cells (91).…”

Section: Metabolic Insult and Mitochondrial Dynamicsmentioning

confidence: 99%

Mitochondrial Morphology in Metabolic Diseases

Galloway

Yoon

2013

Antioxidants & Redox Signaling

112

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Significance: Mitochondria are the cellular energy-producing organelles and are at the crossroad of determining cell life and death. As such, the function of mitochondria has been intensely studied in metabolic disorders, including diabetes and associated maladies commonly grouped under all-inclusive pathological condition of metabolic syndrome. More recently, the altered metabolic profiles and function of mitochondria in these ailments have been correlated with their aberrant morphologies. This review describes an overview of mitochondrial fission and fusion machineries, and discusses implications of mitochondrial morphology and function in these metabolic maladies. Recent Advances: Mitochondria undergo frequent morphological changes, altering the mitochondrial network organization in response to environmental cues, termed mitochondrial dynamics. Mitochondrial fission and fusion mediate morphological plasticity of mitochondria and are controlled by membrane-remodeling mechanochemical enzymes and accessory proteins. Growing evidence suggests that mitochondrial dynamics play an important role in diabetes establishment and progression as well as associated ailments, including, but not limited to, metabolism-secretion coupling in the pancreas, nonalcoholic fatty liver disease progression, and diabetic cardiomyopathy. Critical Issues: While mitochondrial dynamics are intimately associated with mitochondrial bioenergetics, their cause-and-effect correlation remains undefined in metabolic diseases. Future Directions: The involvement of mitochondrial dynamics in metabolic diseases is in its relatively early stages. Elucidating the role of mitochondrial dynamics in pathological metabolic conditions will aid in defining the intricate form-function correlation of mitochondria in metabolic pathologies and should provide not only important clues to metabolic disease progression, but also new therapeutic targets. Antioxid. Redox Signal. 19,[415][416][417][418][419][420][421][422][423][424][425][426][427][428][429][430]

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Different role of saturated and unsaturated fatty acids in β-cell apoptosis

Cited by 119 publications

References 13 publications

Palmitate, but Not Unsaturated Fatty Acids, Induces the Expression of Interleukin-6 in Human Myotubes through Proteasome-dependent Activation of Nuclear Factor-κB

Palmitate, but Not Unsaturated Fatty Acids, Induces the Expression of Interleukin-6 in Human Myotubes through Proteasome-dependent Activation of Nuclear Factor-κB

A Novel Inhibitor of Stearoyl-CoA Desaturase-1 Attenuates Hepatic Lipid Accumulation, Liver Injury and Inflammation in Model of Nonalcoholic Steatohepatitis

Mitochondrial Morphology in Metabolic Diseases

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