Maternal low protein diet-induced low birth weight in male, neonate Sprague-Dawley rats is mediated by altered brown adipose tissue thermogenesis

Authors: Larson, Kate; Dekrey, Emilie; Roemmich, James; RHEN, TURK - University Of North Dakota; GHRIBI, OTHMAN - University Of North Dakota

Submitted to: Keystone Symposia
Publication Type: Abstract Only
Publication Acceptance Date: 2/3/2015
Publication Date: 4/18/2015
Citation: Claycombe, K.J., Dekrey, E.E., Roemmich, J.N., Rhen, T., Ghribi, O. 2015. Maternal low protein diet-induced low birth weight in male, neonate Sprague-Dawley rats is mediated by altered brown adipose tissue thermogenesis [abstract]. Keystone Symposia. April 17-22, 2015. Snowbirth, Utah. p. 50.

Interpretive Summary: Brown adipose tissue (BAT) plays an important role in regulating body weight (BW) by modifying thermogenesis. Maternal low protein (LP) diets reduce offspring birth weight. Increased BAT thermogenesis in utero may be one mechanism for the lower BW. However, whether maternal LP nutrition alters BAT thermogenesis and BW of offspring in-utero is not yet known. We fed obese-prone Sprague-Dawley dams 8% low protein (LP) or 20% normal protein (NP) diets for 3 weeks prior to breeding and through pregnancy. BW and gene expression of interscapular BAT (iBAT) thermogenic markers were measured in male fetal (gestation day 18) and neonatal (day 0 or 1) offspring. BW of neonatal LP males was lower than NP males but no difference was observed in females. Gene and protein expression of UCP-1 and transcription factors PRDM16 and PPARa in iBAT were 2- to 6-fold greater in LP than NP male neonatal offspring. FNDC5, a precursor of irisin and activator of thermogenesis, was expressed 2-fold greater in neonatal LP iBAT than NP males. However, fetal iBAT UCP-1, PRDM16, PPARa and irisin mRNA did not differ between LP and NP groups. Maternal LP diet had no effects on placental irisin and UCP-2 expression. Deiodinase-2 (Dio2) and FNDC5 mRNA expressions were positively correlated with UCP-1 mRNA expression in male neonatal iBAT. These results suggest that prenatal protein restriction increases the risk for low BW through mechanisms affecting full-term offspring iBAT thermogenesis, but not greatly altering fetal iBAT or placental thermogenesis.

Technical Abstract: Brown adipose tissue (BAT) plays an important role in regulating body weight (BW) by modifying thermogenesis. Maternal low protein (LP) diets reduce offspring birth weight. Increased BAT thermogenesis in utero may be one mechanism for the lower BW. However, whether maternal LP nutrition alters BAT thermogenesis and BW of offspring in-utero is not yet known. We fed obese-prone Sprague-Dawley dams 8% low protein (LP) or 20% normal protein (NP) diets for 3 weeks prior to breeding and through pregnancy. BW and gene expression of interscapular BAT (iBAT) thermogenic markers were measured in male fetal (gestation day 18) and neonatal (day 0 or 1) offspring. BW of neonatal LP males was lower than NP males but no difference was observed in females. Gene and protein expression of UCP-1 and transcription factors PRDM16 and PPARa in iBAT were 2- to 6-fold greater in LP than NP male neonatal offspring. FNDC5, a precursor of irisin and activator of thermogenesis, was expressed 2-fold greater in neonatal LP iBAT than NP males. However, fetal iBAT UCP-1, PRDM16, PPARa and irisin mRNA did not differ between LP and NP groups. Maternal LP diet had no effects on placental irisin and UCP-2 expression. Deiodinase-2 (Dio2) and FNDC5 mRNA expressions were positively correlated with UCP-1 mRNA expression in male neonatal iBAT. These results suggest that prenatal protein restriction increases the risk for low BW through mechanisms affecting full-term offspring iBAT thermogenesis, but not greatly altering fetal iBAT or placental thermogenesis.