Elevated Carbohydrate Response Element-Binding Protein Beta (ChREBPβ) and Thioredoxin Interacting Protein (TXNIP) Levels in Human Adipocytes Differentiated in High Glucose Concentrations.

Abstract

Obesity and type 2 diabetes often coexist. The effect of hyperglycemia on adipose tissue is, therefore, of interest. Although studies have shown that high glucose (HG) concentrations do not inhibit adipocyte differentiation, the resulting adipocyte phenotype has not been investigated. In particular, the levels of the glucose-responsive transcription factor carbohydrate-responsive response element binding protein (ChREBP) isoforms have not been assessed. Human preadipocytes were differentiated into adipocytes in either normal glucose (NG) or HG conditions. RNA and protein analyses were used to measure the expression of ChREBP isoforms, thioredoxin interacting protein (TXNIP) and lipogenic genes. Insulin-stimulated glucose uptake was measured. HG- vs. NG-differentiated adipocytes expressed more ChREBPβ and more TXNIP at the mRNA and protein levels. There was no change in lipogenic gene expression. HG- vs. NG-differentiated adipocytes displayed an inhibition of insulin-stimulated glucose uptake. HG-differentiated human adipocytes have distinct molecular differences and are insulin resistant. More studies are warranted to investigate potential mechanisms linking changes in ChREBPβ and TXNIP to insulin responsiveness.