Abstract
The purpose of this study was to examine the hypothesis that excess maternal glucocorticoids in response to maternal undernutrition programs the expression of extracellular matrix (ECM) components potentially by miR-29c. We measured the expression of mRNA (qRT-PCR) and protein (Western blot) for collagen 3A1, collagen 4A5 and matrix metalloproteinase 2 (MMP2) in offspring carotid arteries from three groups of dams: 50% food-restricted in latter half of gestation [maternal undernutrition (MUN)], MUN dams who received metyrapone (MET) (500 mg/ml ) in drinking water from day 10 of gestation to term, and control dams fed an ad libitum diet. The expression of miR-29c was significantly decreased at 3 weeks, 3 months and 9 months in MUN carotid arteries, and these decreases in expression were partially blocked by treatment of dams with MET. The expression pattern of ECM genes that are targets of miR-29c correlated with miR-29c expression. Expression of mRNA was increased for elastin (ELN) and MMP2 mRNA in 3-week MUN carotids; in 9-month carotids there were also significant increases in expression of Col3A1 and Col4A5. These changes in mRNA expression of ECM genes at 3 weeks and 9 months were blocked by MET treatment. Similarly, the expression of ELN and MMP2 proteins at 3 weeks were increased in MUN carotids, and by 9 months there were also increases in expression of Col3A1 and Col4A5, which were blocked by MET in MUN carotids. Overall, the results demonstrate a close correlation between expression of miR-29c and the ECM proteins that are its targets thus supporting our central hypothesis.