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- Title
Full-Length Adiponectin Attenuates Insulin Signaling and Inhibits Insulin-Stimulated Amino Acid Transport in Human Primary Trophoblast Cells.
- Authors
Jones, Helen N.; Jansson, Thomas; Powell, Theresa L.
- Abstract
OBJECTIVE--Maternal adiponectin levels are reduced and placental nutrient transporters are upregulated in obesity and gestational diabetes mellitus; however, the effects of adiponectin on placental function are unknown. We hypothesized that adiponectin regulates placental amino acid transport. RESEARCH DESIGN AND METHODS--Human primary trophoblast cells were cultured and incubated with globular adiponectin (gAd) or full-length adiponectin (fAd) alone or in combination with insulin. System A and L amino acid transport and SNAT1, SNAT2, and SNAT4 isoform expression was measured. The activity of the AMP-activated protein kinase (AMPK), phosphatidylinositol 3 kinase-AKT, and peroxisome proliferator--activated receptor-α (PPARα) signaling pathways was determined. RESULTS--In the absence of insulin, gAd stimulated AMPK Thr172 phosphorylation, SNAT2 protein expression, and system A activity. This effect appeared to be mediated by interleukin-6 release and signal transducer and activator of transcription 3 (STAT3) signaling because gAd failed to stimulate system A in cells in which STAT3 had been silenced using small interfering RNA. fAd alone had no effect on system A activity or SNAT expression. Insulin increased AKT and insulin receptor substrate 1 (IRS-1) phosphorylation, system A activity, and SNAT2 expression. When combined with insulin, gAd did not affect system A activity or SNAT expression. In contrast, fAd abolished insulin-stimulated AKT Thr308 and IRS-1 Tyr612 phosphorylation, system A activity, and SNAT2 expression. Furthermore, fAd increased PPARα expression and PPARα (Ser21) phosphorylation. CONCLUSIONS--In contrast to the insulin-sensitizing actions of adiponectin in liver and muscle reported in the literature, fAd attenuates insulin signaling in primary human trophoblast cells. As a result, fAd inhibits insulin-stimulated amino acid transport, which may have important implications for placental nutrient transport and fetal growth in pregnancy complications associated with altered maternal adiponectin levels. Diabetes 59: 1161-1170, 2010
- Subjects
AMINO acids; DIABETES; PROINSULIN; TROPHOBLAST; CARBOHYDRATE intolerance; PROTEIN kinases; PHOSPHORYLATION
- Publication
Diabetes, 2010, Vol 59, Issue 5, p1161
- ISSN
0012-1797
- Publication type
Article
- DOI
10.2337/db09-0824