Activation of placental insulin and mTOR signaling in a mouse model of maternal obesity associated with fetal overgrowth.
Am J Physiol Regul Integr Comp Physiol
; 310(1): R87-93, 2016 Jan 01.
Article
em En
| MEDLINE
| ID: mdl-26491103
ABSTRACT
Fetal overgrowth is common in obese women and is associated with perinatal complications and increased risk for the child to develop metabolic syndrome later in life. Placental nutrient transport capacity has been reported to be increased in obese women giving birth to large infants; however, the underlying mechanisms are not well established. Obesity in pregnancy is characterized by elevated maternal serum insulin and leptin, hormones that stimulate placental amino acid transporters in vitro. We hypothesized that maternal obesity activates placental insulin/IGF-I/mTOR and leptin signaling pathways. We tested this hypothesis in a mouse model of obesity in pregnancy that is associated with fetal overgrowth. C57BL/6J female mice were fed a control (C) or a high-fat/high-sugar (HF/HS) pelleted diet supplemented by ad libitum access to sucrose (20%) solution. Placentas were collected at embryonic day 18.5. Using Western blot analysis, placental mTOR activity was determined along with energy, inflammatory, leptin, and insulin signaling pathways (upstream modulators of mTOR). Phosphorylation of S6 ribosomal protein (S-235/236), 4E-BP1 (T-37/46), Insulin receptor substrate 1 (Y-608), Akt (T-308), and STAT-3 (Y-705) was increased in obese dams. In contrast, expression of placental caspase-1, IкBα, IL-1ß, and phosphorylated-JNK(p46/54-T183/Y185) was unaltered. Fetal amino acid availability is a key determinant of fetal growth. We propose that activation of placental insulin/IGF-I/mTOR and leptin signaling pathways in obese mice stimulates placental amino acid transport and contributes to increased fetal growth.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Placenta
/
Transdução de Sinais
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Estado Nutricional
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Peso Fetal
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Transtornos da Nutrição Fetal
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Serina-Treonina Quinases TOR
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Insulina
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Obesidade
Tipo de estudo:
Prognostic_studies
/
Risk_factors_studies
Limite:
Animals
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Pregnancy
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article