Effect of TNF-alpha on molecules related to the Iinsulin action in endometrial cells exposed to hyperandrogenic and hyperinsulinic conditions characteristics of polycystic ovary syndrome

Abstract

Polycystic ovary syndrome (PCOS) affects not only ovarian functions but is also able to affect endometrium metabolism. Around 80% of women with PCOS are obese. High tumor necrosis factor (TNF)- production and low adiponectin levels are characteristics of obesity. Interestingly, endometrium from obese women with PCOS presents an insulin-resistance condition, high TNF- levels, and low adiponectin levels. However, TNF- effect on molecules associated with insulin action in endometrial cells remains unclear. Therefore, the objective of this work was to evaluate TNF- effect on expression of molecules associated with adiponectin (insulin sensitizing) and TNF- signaling pathways and on Glucose Transporter type 4 (GLUT-4) levels in human endometrial cells under the characteristic conditions of hyperandrogenic/hyperinsulinic (HA/HI) PCOS. Two human endometrial stromal cell lines (T-HESC/St-T1b) under HA/HI conditions were used to assay the effect of high TNF- concentration (100 ng/mL) on adiponectin, AdipoR1-AdipoR2 receptors, Adaptor protein phosphotyrosine interacting with PH domain and leucine zipper 1 (APPL1), Phospho-AMP-activated protein kinase T172 (p-AMPKT172), GLUT-4, Tumor necrosis factor receptor 1 (TNFR1)-Tumor necrosis factor receptor 2 (TNFR2) receptors protein levels, and nuclear factor B (NFB) nuclear content, by Western blot or immunocytochemistry. The NFB participation in TNF- effect on adiponectin expression was assayed using an NFB inhibitor (pyrrolidine dithiocarbamate). The TNF- increases the expression of molecules associated with its own signaling pathway (P < .05) and decreases the protein levels of adiponectin and its associated molecules (P < .05). Moreover, TNF- increases NFB nuclear content (P < .001), whereas with NFB inhibition the decrease in adiponectin content induced by TNF- was not observed. GLUT-4 levels were lower with TNF- treatment (P < .01). Thus, in human endometrial stromal cells, high TNF- levels negatively affect the insulin action through decreased adiponectin signaling and GLUT-4 protein. This could explain the failures observed in endometrial function of obese women with PCOS.