202. Differential dietary regulation of placental and muscle myostatin in a transgenerational rat model of maternal under-nutrition
H. N. Peiris A , S. Tovey A , M. D. Mitchell A B , M. P. Green A B C and A. P. Ponnampalam AA Liggins Institute, The University of Auckland, Grafton, Auckland, New Zealand.
B National Research Centre for Growth and Development, Auckland, New Zealand.
C AgResearch Ltd, Hamilton, New Zealand.
Reproduction, Fertility and Development 20(9) 2-2 https://doi.org/10.1071/SRB08Abs202
Published: 28 August 2008
Abstract
Myostatin, a negative regulator of muscle growth, affects glucose uptake independent of insulin and also regulates placental glucose uptake in vitro in the human placenta. Maternal under-nutrition during early gestation has been associated with fetal programming for increased risk of metabolic disorders in later life. The aim of this project was to investigate changes in myostatin expression in placental and muscle samples in an established rat model of fetal programming. Pregnant rats were fed either a standard diet ad libitum (AD) or 30% of ad libitum (UN) throughout gestation. Female F1 offspring were in turn subjected to AD or UN conditions throughout pregnancy, giving three groups of F2 offspring: AD-AD, AD-UN and UN-AD. The F2 rats were then fed either a chow or a high fat (HF, 65% kcals fat) diet. Muscle and placental samples were collected at various time-points for analysis of myostatin and pro-myostatin expression. Myostatin mRNA expression was found to be significantly higher in placentae compared with skeletal muscle samples, and in UN-AD muscle compared with AD-AD muscle. At the protein level, expression of both myostatin dimer and precursor varied with time and across groups: particularly, placental myostatin dimer expression was significantly higher in UNAD females compared with ADUN and ADAD groups; muscle myostatin precursor expression was reduced in AD-UN and UN-AD females compared with the AD-AD group at embryonic day20; while at day140, there was a trend towards an increase in muscle myostatin dimer expression in UN-AD HF fed compared with UN-AD CHOW animals. Our data demonstrate that in response to maternal diet myostatin is differentially regulated in placentae compared with skeletal muscle, with both myostatin dimer and myostatin precursor levels affected. Modulation of placental myostatin activity through changes in relative expression of myostatin dimer and myostatin precursor in response to maternal diet may contribute to aberrant nutritional uptake by the fetus.
