Ganguly Amit, Touma Marlin, Thamotharan Shanthie, De Vivo Darryl C, Devaskar Sherin U
Department of Pediatrics (A.G., M.T., S.T., S.U.D.), Division of Neonatology and Developmental Biology, and Neonatal Research Center at the UCLA Children's Discovery and Innovation Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095; and Department of Neurology (D.C.D.V.), Columbia University College of Physicians and Surgeons, New York, New York 10032.
Endocrinology. 2016 Oct;157(10):4041-4054. doi: 10.1210/en.2016-1259. Epub 2016 Aug 5.
We examined the effect of mild (Mi; ∼25%) and moderate (Mo; ∼50%) maternal calorie restriction (MCR) vs ad libitum-fed controls on placental glucose and leucine transport impacting fetal growth potential. We observed in MiMCR a compensatory increase in transplacental (TP) glucose transport due to increased placental glucose transporter isoform (GLUT)-3 but no change in GLUT1 protein concentrations. This change was paralleled by increased glut3 mRNA and 5-hydroxymethylated cytosines with enhanced recruitment of histone 3 lysine demethylase to the glut3 gene locus. To assess the biologic relevance of placental GLUT1, we also examined glut1 heterozygous null vs wild-type mice and observed no difference in placental GLUT3 and TP or intraplacental glucose and leucine transport. Both MCR states led to a graded decrease in TP and intraplacental leucine transport, with a decline in placental L amino acid transporter isoform 2 (LAT2) concentrations and increased microRNA-149 (targets LAT2) and microRNA-122 (targets GLUT3) expression in MoMCR alone. These changes were accompanied by a step-wise reduction in uterine and umbilical artery Doppler blood flow with decreased fetal left ventricular ejection fraction and fractional shortening. We conclude that MiMCR transactivates placental GLUT3 toward preserving TP glucose transport in the face of reduced leucine transport. This contrasts MoMCR in which a reduction in placental GLUT3 mediated glucose transport with a reciprocal increase in miR-122 expression was encountered. A posttranscriptional reduction in LAT2-mediated leucine transport also occurred with enhanced miR-149 expression. Both MCR states, although not affecting placental GLUT1, resulted in uteroplacental insufficiency and fetal growth restriction with compromised cardiovascular health.
我们研究了轻度(Mi;约25%)和中度(Mo;约50%)母体热量限制(MCR)与自由采食对照组相比,对胎盘葡萄糖和亮氨酸转运的影响,这会影响胎儿的生长潜力。我们观察到,在轻度母体热量限制组中,由于胎盘葡萄糖转运蛋白异构体(GLUT)-3增加,经胎盘(TP)葡萄糖转运出现代偿性增加,但GLUT1蛋白浓度没有变化。这种变化与glut3 mRNA和5-羟甲基化胞嘧啶的增加以及组蛋白3赖氨酸去甲基化酶向glut3基因位点的募集增强相平行。为了评估胎盘GLUT1的生物学相关性,我们还研究了glut1杂合缺失小鼠与野生型小鼠,并未观察到胎盘GLUT3和经胎盘转运或胎盘内葡萄糖和亮氨酸转运存在差异。两种母体热量限制状态均导致经胎盘和胎盘内亮氨酸转运呈分级下降,仅在中度母体热量限制组中,胎盘L氨基酸转运蛋白异构体2(LAT2)浓度下降,且微小RNA-14(靶向LAT2)和微小RNA-122(靶向GLUT3)表达增加。这些变化伴随着子宫和脐动脉多普勒血流的逐步减少,同时胎儿左心室射血分数和缩短分数降低。我们得出结论,在亮氨酸转运减少的情况下,轻度母体热量限制通过激活胎盘GLUT3来维持经胎盘葡萄糖转运。这与中度母体热量限制形成对比,在中度母体热量限制中,胎盘GLUT3介导的葡萄糖转运减少,同时miR-122表达相应增加。LAT2介导的亮氨酸转运在转录后也减少,同时miR-149表达增强。两种母体热量限制状态虽然不影响胎盘GLUT1,但均导致子宫胎盘功能不全和胎儿生长受限,并损害心血管健康。