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Myotubes from severely obese type 2 diabetic subjects accumulate less lipids and show higher lipolytic rate than myotubes from severely obese non-diabetic subjects.

Bakke SS, Feng YZ, Nikolić N, Kase ET, Moro C, Stensrud C, Damlien L, Ludahl MO, Sandbu R, Solheim BM, Rustan AC, Hjelmesæth J, Thoresen GH, Aas V - PLoS ONE (2015)

Bottom Line: There were no differences in lipid distribution and mRNA and protein expression of the lipases HSL and ATGL, the lipase cofactor CGI-58, or the lipid droplet proteins PLIN2 and PLIN3.Glucose and oleic acid oxidation were also similar in cells from the two groups.In conclusion, myotubes established from severely obese donors with established type 2 diabetes had lower ability for lipid accumulation and higher lipolysis rate than myotubes from severely obese donors without diabetes.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway.

ABSTRACT
About 80% of patients with type 2 diabetes are classified as overweight. However, only about 1/3 of severely obese subjects have type 2 diabetes. This indicates that several severely obese individuals may possess certain characteristics that protect them against type 2 diabetes. We therefore hypothesized that this apparent paradox could be related to fundamental differences in skeletal muscle lipid handling. Energy metabolism and metabolic flexibility were examined in human myotubes derived from severely obese subjects without (BMI 44±7 kg/m2) and with type 2 diabetes (BMI 43±6 kg/m2). Lower insulin sensitivity was observed in myotubes from severely obese subjects with type 2 diabetes. Lipolysis rate was higher, and oleic acid accumulation, triacylglycerol content, and fatty acid adaptability were lower in myotubes from severely obese subjects with type 2 diabetes compared to severely obese non-diabetic subjects. There were no differences in lipid distribution and mRNA and protein expression of the lipases HSL and ATGL, the lipase cofactor CGI-58, or the lipid droplet proteins PLIN2 and PLIN3. Glucose and oleic acid oxidation were also similar in cells from the two groups. In conclusion, myotubes established from severely obese donors with established type 2 diabetes had lower ability for lipid accumulation and higher lipolysis rate than myotubes from severely obese donors without diabetes. This indicates that a difference in intramyocellular lipid turnover might be fundamental in evolving type 2 diabetes.

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Decreased insulin-stimulated glucose uptake and Akt phosphorylation in myotubes from severely obese donors with type 2 diabetes.(A) Myotubes from severely obese non-diabetic donors (nD) and severely obese donors with type 2 diabetes (T2D) were incubated for 15 min with or without 100 nM insulin, before immunoblotting analysis with antibodies against phosho-Akt (Ser473) and total-Akt were performed. Data are shown as ratio phosho-Akt/total Akt and related to unstimulated cells (n = 4–5). Immunoblotting from one representative experiment. (B) Glucose uptake was measured by [3H]deoxyglucose with or without 100 nM insulin for 1 h. Basal glucose uptake was 251 ± 68 nmol/mg protein (nD) and 203 ± 34 nmol/mg protein (T2D). Data are presented as mean ± SEM normalized to unstimulated cells, n = 7–8, #p < 0.05 versus basal, *p < 0.05 versus nD.
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pone.0119556.g001: Decreased insulin-stimulated glucose uptake and Akt phosphorylation in myotubes from severely obese donors with type 2 diabetes.(A) Myotubes from severely obese non-diabetic donors (nD) and severely obese donors with type 2 diabetes (T2D) were incubated for 15 min with or without 100 nM insulin, before immunoblotting analysis with antibodies against phosho-Akt (Ser473) and total-Akt were performed. Data are shown as ratio phosho-Akt/total Akt and related to unstimulated cells (n = 4–5). Immunoblotting from one representative experiment. (B) Glucose uptake was measured by [3H]deoxyglucose with or without 100 nM insulin for 1 h. Basal glucose uptake was 251 ± 68 nmol/mg protein (nD) and 203 ± 34 nmol/mg protein (T2D). Data are presented as mean ± SEM normalized to unstimulated cells, n = 7–8, #p < 0.05 versus basal, *p < 0.05 versus nD.

Mentions: To confirm that the myotubes maintained their diabetic phenotype in culture, insulin-stimulated glucose uptake and Akt phosphorylation (Ser473) were measured. Insulin-stimulated phosphorylation of Akt tended to be lower in myotubes from severely obese donors with type 2 diabetes compared to severely obese donors with normal glucose tolerance (Fig. 1A, p = 0.11). Insulin-stimulated glucose uptake was abolished in myotubes from type 2 diabetics compared to cells from non-diabetics (Fig. 1B, p = 0.01), implying a conserved insulin resistance in cultured cells.


Myotubes from severely obese type 2 diabetic subjects accumulate less lipids and show higher lipolytic rate than myotubes from severely obese non-diabetic subjects.

Bakke SS, Feng YZ, Nikolić N, Kase ET, Moro C, Stensrud C, Damlien L, Ludahl MO, Sandbu R, Solheim BM, Rustan AC, Hjelmesæth J, Thoresen GH, Aas V - PLoS ONE (2015)

Decreased insulin-stimulated glucose uptake and Akt phosphorylation in myotubes from severely obese donors with type 2 diabetes.(A) Myotubes from severely obese non-diabetic donors (nD) and severely obese donors with type 2 diabetes (T2D) were incubated for 15 min with or without 100 nM insulin, before immunoblotting analysis with antibodies against phosho-Akt (Ser473) and total-Akt were performed. Data are shown as ratio phosho-Akt/total Akt and related to unstimulated cells (n = 4–5). Immunoblotting from one representative experiment. (B) Glucose uptake was measured by [3H]deoxyglucose with or without 100 nM insulin for 1 h. Basal glucose uptake was 251 ± 68 nmol/mg protein (nD) and 203 ± 34 nmol/mg protein (T2D). Data are presented as mean ± SEM normalized to unstimulated cells, n = 7–8, #p < 0.05 versus basal, *p < 0.05 versus nD.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4366103&req=5

pone.0119556.g001: Decreased insulin-stimulated glucose uptake and Akt phosphorylation in myotubes from severely obese donors with type 2 diabetes.(A) Myotubes from severely obese non-diabetic donors (nD) and severely obese donors with type 2 diabetes (T2D) were incubated for 15 min with or without 100 nM insulin, before immunoblotting analysis with antibodies against phosho-Akt (Ser473) and total-Akt were performed. Data are shown as ratio phosho-Akt/total Akt and related to unstimulated cells (n = 4–5). Immunoblotting from one representative experiment. (B) Glucose uptake was measured by [3H]deoxyglucose with or without 100 nM insulin for 1 h. Basal glucose uptake was 251 ± 68 nmol/mg protein (nD) and 203 ± 34 nmol/mg protein (T2D). Data are presented as mean ± SEM normalized to unstimulated cells, n = 7–8, #p < 0.05 versus basal, *p < 0.05 versus nD.
Mentions: To confirm that the myotubes maintained their diabetic phenotype in culture, insulin-stimulated glucose uptake and Akt phosphorylation (Ser473) were measured. Insulin-stimulated phosphorylation of Akt tended to be lower in myotubes from severely obese donors with type 2 diabetes compared to severely obese donors with normal glucose tolerance (Fig. 1A, p = 0.11). Insulin-stimulated glucose uptake was abolished in myotubes from type 2 diabetics compared to cells from non-diabetics (Fig. 1B, p = 0.01), implying a conserved insulin resistance in cultured cells.

Bottom Line: There were no differences in lipid distribution and mRNA and protein expression of the lipases HSL and ATGL, the lipase cofactor CGI-58, or the lipid droplet proteins PLIN2 and PLIN3.Glucose and oleic acid oxidation were also similar in cells from the two groups.In conclusion, myotubes established from severely obese donors with established type 2 diabetes had lower ability for lipid accumulation and higher lipolysis rate than myotubes from severely obese donors without diabetes.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway.

ABSTRACT
About 80% of patients with type 2 diabetes are classified as overweight. However, only about 1/3 of severely obese subjects have type 2 diabetes. This indicates that several severely obese individuals may possess certain characteristics that protect them against type 2 diabetes. We therefore hypothesized that this apparent paradox could be related to fundamental differences in skeletal muscle lipid handling. Energy metabolism and metabolic flexibility were examined in human myotubes derived from severely obese subjects without (BMI 44±7 kg/m2) and with type 2 diabetes (BMI 43±6 kg/m2). Lower insulin sensitivity was observed in myotubes from severely obese subjects with type 2 diabetes. Lipolysis rate was higher, and oleic acid accumulation, triacylglycerol content, and fatty acid adaptability were lower in myotubes from severely obese subjects with type 2 diabetes compared to severely obese non-diabetic subjects. There were no differences in lipid distribution and mRNA and protein expression of the lipases HSL and ATGL, the lipase cofactor CGI-58, or the lipid droplet proteins PLIN2 and PLIN3. Glucose and oleic acid oxidation were also similar in cells from the two groups. In conclusion, myotubes established from severely obese donors with established type 2 diabetes had lower ability for lipid accumulation and higher lipolysis rate than myotubes from severely obese donors without diabetes. This indicates that a difference in intramyocellular lipid turnover might be fundamental in evolving type 2 diabetes.

Show MeSH
Related in: MedlinePlus